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, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, 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, int);
  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 default_function_array_conversion (tree);
  84 static tree lookup_field (tree, tree);
  85 static tree convert_arguments (tree, tree, tree, tree);
  86 static tree pointer_diff (tree, tree);
  87 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  88                                     int);
  89 static tree valid_compound_expr_initializer (tree, tree);
  90 static void push_string (const char *);
  91 static void push_member_name (tree);
  92 static void push_array_bounds (int);
  93 static int spelling_length (void);
  94 static char *print_spelling (char *);
  95 static void warning_init (const char *);
  96 static tree digest_init (tree, tree, bool, int);
  97 static void output_init_element (tree, bool, tree, tree, int);
  98 static void output_pending_init_elements (int);
  99 static int set_designator (int);
 100 static void push_range_stack (tree);
 101 static void add_pending_init (tree, tree);
 102 static void set_nonincremental_init (void);
 103 static void set_nonincremental_init_from_string (tree);
 104 static tree find_init_member (tree);
 105 static void readonly_error (tree, enum lvalue_use);
 106 static int lvalue_or_else (tree, enum lvalue_use);
 107 static int lvalue_p (tree);
 108 static void record_maybe_used_decl (tree);
 109 \f
 110 /* Do `exp = require_complete_type (exp);' to make sure exp
 111    does not have an incomplete type.  (That includes void types.)  */
 112
 113 tree
 114 require_complete_type (tree value)
 115 {
 116   tree type = TREE_TYPE (value);
 117
 118   if (value == error_mark_node || type == error_mark_node)
 119     return error_mark_node;
 120
 121   /* First, detect a valid value with a complete type.  */
 122   if (COMPLETE_TYPE_P (type))
 123     return value;
 124
 125   c_incomplete_type_error (value, type);
 126   return error_mark_node;
 127 }
 128
 129 /* Print an error message for invalid use of an incomplete type.
 130    VALUE is the expression that was used (or 0 if that isn't known)
 131    and TYPE is the type that was invalid.  */
 132
 133 void
 134 c_incomplete_type_error (tree value, tree type)
 135 {
 136   const char *type_code_string;
 137
 138   /* Avoid duplicate error message.  */
 139   if (TREE_CODE (type) == ERROR_MARK)
 140     return;
 141
 142   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 143                      || TREE_CODE (value) == PARM_DECL))
 144     error ("%qD has an incomplete type", value);
 145   else
 146     {
 147     retry:
 148       /* We must print an error message.  Be clever about what it says.  */
 149
 150       switch (TREE_CODE (type))
 151         {
 152         case RECORD_TYPE:
 153           type_code_string = "struct";
 154           break;
 155
 156         case UNION_TYPE:
 157           type_code_string = "union";
 158           break;
 159
 160         case ENUMERAL_TYPE:
 161           type_code_string = "enum";
 162           break;
 163
 164         case VOID_TYPE:
 165           error ("invalid use of void expression");
 166           return;
 167
 168         case ARRAY_TYPE:
 169           if (TYPE_DOMAIN (type))
 170             {
 171               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 172                 {
 173                   error ("invalid use of flexible array member");
 174                   return;
 175                 }
 176               type = TREE_TYPE (type);
 177               goto retry;
 178             }
 179           error ("invalid use of array with unspecified bounds");
 180           return;
 181
 182         default:
 183           gcc_unreachable ();
 184         }
 185
 186       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 187         error ("invalid use of undefined type %<%s %E%>",
 188                type_code_string, TYPE_NAME (type));
 189       else
 190         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 191         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 192     }
 193 }
 194
 195 /* Given a type, apply default promotions wrt unnamed function
 196    arguments and return the new type.  */
 197
 198 tree
 199 c_type_promotes_to (tree type)
 200 {
 201   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 202     return double_type_node;
 203
 204   if (c_promoting_integer_type_p (type))
 205     {
 206       /* Preserve unsignedness if not really getting any wider.  */
 207       if (TYPE_UNSIGNED (type)
 208           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 209         return unsigned_type_node;
 210       return integer_type_node;
 211     }
 212
 213   return type;
 214 }
 215
 216 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 217    as well as those of TYPE.  */
 218
 219 static tree
 220 qualify_type (tree type, tree like)
 221 {
 222   return c_build_qualified_type (type,
 223                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 224 }
 225 \f
 226 /* Return the composite type of two compatible types.
 227
 228    We assume that comptypes has already been done and returned
 229    nonzero; if that isn't so, this may crash.  In particular, we
 230    assume that qualifiers match.  */
 231
 232 tree
 233 composite_type (tree t1, tree t2)
 234 {
 235   enum tree_code code1;
 236   enum tree_code code2;
 237   tree attributes;
 238
 239   /* Save time if the two types are the same.  */
 240
 241   if (t1 == t2) return t1;
 242
 243   /* If one type is nonsense, use the other.  */
 244   if (t1 == error_mark_node)
 245     return t2;
 246   if (t2 == error_mark_node)
 247     return t1;
 248
 249   code1 = TREE_CODE (t1);
 250   code2 = TREE_CODE (t2);
 251
 252   /* Merge the attributes.  */
 253   attributes = targetm.merge_type_attributes (t1, t2);
 254
 255   /* If one is an enumerated type and the other is the compatible
 256      integer type, the composite type might be either of the two
 257      (DR#013 question 3).  For consistency, use the enumerated type as
 258      the composite type.  */
 259
 260   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 261     return t1;
 262   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 263     return t2;
 264
 265   gcc_assert (code1 == code2);
 266
 267   switch (code1)
 268     {
 269     case POINTER_TYPE:
 270       /* For two pointers, do this recursively on the target type.  */
 271       {
 272         tree pointed_to_1 = TREE_TYPE (t1);
 273         tree pointed_to_2 = TREE_TYPE (t2);
 274         tree target = composite_type (pointed_to_1, pointed_to_2);
 275         t1 = build_pointer_type (target);
 276         t1 = build_type_attribute_variant (t1, attributes);
 277         return qualify_type (t1, t2);
 278       }
 279
 280     case ARRAY_TYPE:
 281       {
 282         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 283         int quals;
 284         tree unqual_elt;
 285
 286         /* We should not have any type quals on arrays at all.  */
 287         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 288
 289         /* Save space: see if the result is identical to one of the args.  */
 290         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
 291           return build_type_attribute_variant (t1, attributes);
 292         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
 293           return build_type_attribute_variant (t2, attributes);
 294
 295         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 296           return build_type_attribute_variant (t1, attributes);
 297         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 298           return build_type_attribute_variant (t2, attributes);
 299
 300         /* Merge the element types, and have a size if either arg has
 301            one.  We may have qualifiers on the element types.  To set
 302            up TYPE_MAIN_VARIANT correctly, we need to form the
 303            composite of the unqualified types and add the qualifiers
 304            back at the end.  */
 305         quals = TYPE_QUALS (strip_array_types (elt));
 306         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 307         t1 = build_array_type (unqual_elt,
 308                                TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
 309         t1 = c_build_qualified_type (t1, quals);
 310         return build_type_attribute_variant (t1, attributes);
 311       }
 312
 313     case FUNCTION_TYPE:
 314       /* Function types: prefer the one that specified arg types.
 315          If both do, merge the arg types.  Also merge the return types.  */
 316       {
 317         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 318         tree p1 = TYPE_ARG_TYPES (t1);
 319         tree p2 = TYPE_ARG_TYPES (t2);
 320         int len;
 321         tree newargs, n;
 322         int i;
 323
 324         /* Save space: see if the result is identical to one of the args.  */
 325         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 326           return build_type_attribute_variant (t1, attributes);
 327         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 328           return build_type_attribute_variant (t2, attributes);
 329
 330         /* Simple way if one arg fails to specify argument types.  */
 331         if (TYPE_ARG_TYPES (t1) == 0)
 332          {
 333             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 334             t1 = build_type_attribute_variant (t1, attributes);
 335             return qualify_type (t1, t2);
 336          }
 337         if (TYPE_ARG_TYPES (t2) == 0)
 338          {
 339            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 340            t1 = build_type_attribute_variant (t1, attributes);
 341            return qualify_type (t1, t2);
 342          }
 343
 344         /* If both args specify argument types, we must merge the two
 345            lists, argument by argument.  */
 346         /* Tell global_bindings_p to return false so that variable_size
 347            doesn't die on VLAs in parameter types.  */
 348         c_override_global_bindings_to_false = true;
 349
 350         len = list_length (p1);
 351         newargs = 0;
 352
 353         for (i = 0; i < len; i++)
 354           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 355
 356         n = newargs;
 357
 358         for (; p1;
 359              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 360           {
 361             /* A null type means arg type is not specified.
 362                Take whatever the other function type has.  */
 363             if (TREE_VALUE (p1) == 0)
 364               {
 365                 TREE_VALUE (n) = TREE_VALUE (p2);
 366                 goto parm_done;
 367               }
 368             if (TREE_VALUE (p2) == 0)
 369               {
 370                 TREE_VALUE (n) = TREE_VALUE (p1);
 371                 goto parm_done;
 372               }
 373
 374             /* Given  wait (union {union wait *u; int *i} *)
 375                and  wait (union wait *),
 376                prefer  union wait *  as type of parm.  */
 377             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 378                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 379               {
 380                 tree memb;
 381                 tree mv2 = TREE_VALUE (p2);
 382                 if (mv2 && mv2 != error_mark_node
 383                     && TREE_CODE (mv2) != ARRAY_TYPE)
 384                   mv2 = TYPE_MAIN_VARIANT (mv2);
 385                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 386                      memb; memb = TREE_CHAIN (memb))
 387                   {
 388                     tree mv3 = TREE_TYPE (memb);
 389                     if (mv3 && mv3 != error_mark_node
 390                         && TREE_CODE (mv3) != ARRAY_TYPE)
 391                       mv3 = TYPE_MAIN_VARIANT (mv3);
 392                     if (comptypes (mv3, mv2))
 393                       {
 394                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 395                                                          TREE_VALUE (p2));
 396                         if (pedantic)
 397                           pedwarn ("function types not truly compatible in ISO C");
 398                         goto parm_done;
 399                       }
 400                   }
 401               }
 402             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 403                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 404               {
 405                 tree memb;
 406                 tree mv1 = TREE_VALUE (p1);
 407                 if (mv1 && mv1 != error_mark_node
 408                     && TREE_CODE (mv1) != ARRAY_TYPE)
 409                   mv1 = TYPE_MAIN_VARIANT (mv1);
 410                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 411                      memb; memb = TREE_CHAIN (memb))
 412                   {
 413                     tree mv3 = TREE_TYPE (memb);
 414                     if (mv3 && mv3 != error_mark_node
 415                         && TREE_CODE (mv3) != ARRAY_TYPE)
 416                       mv3 = TYPE_MAIN_VARIANT (mv3);
 417                     if (comptypes (mv3, mv1))
 418                       {
 419                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 420                                                          TREE_VALUE (p1));
 421                         if (pedantic)
 422                           pedwarn ("function types not truly compatible in ISO C");
 423                         goto parm_done;
 424                       }
 425                   }
 426               }
 427             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 428           parm_done: ;
 429           }
 430
 431         c_override_global_bindings_to_false = false;
 432         t1 = build_function_type (valtype, newargs);
 433         t1 = qualify_type (t1, t2);
 434         /* ... falls through ...  */
 435       }
 436
 437     default:
 438       return build_type_attribute_variant (t1, attributes);
 439     }
 440
 441 }
 442
 443 /* Return the type of a conditional expression between pointers to
 444    possibly differently qualified versions of compatible types.
 445
 446    We assume that comp_target_types has already been done and returned
 447    nonzero; if that isn't so, this may crash.  */
 448
 449 static tree
 450 common_pointer_type (tree t1, tree t2)
 451 {
 452   tree attributes;
 453   tree pointed_to_1, mv1;
 454   tree pointed_to_2, mv2;
 455   tree target;
 456
 457   /* Save time if the two types are the same.  */
 458
 459   if (t1 == t2) return t1;
 460
 461   /* If one type is nonsense, use the other.  */
 462   if (t1 == error_mark_node)
 463     return t2;
 464   if (t2 == error_mark_node)
 465     return t1;
 466
 467   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 468               && TREE_CODE (t2) == POINTER_TYPE);
 469
 470   /* Merge the attributes.  */
 471   attributes = targetm.merge_type_attributes (t1, t2);
 472
 473   /* Find the composite type of the target types, and combine the
 474      qualifiers of the two types' targets.  Do not lose qualifiers on
 475      array element types by taking the TYPE_MAIN_VARIANT.  */
 476   mv1 = pointed_to_1 = TREE_TYPE (t1);
 477   mv2 = pointed_to_2 = TREE_TYPE (t2);
 478   if (TREE_CODE (mv1) != ARRAY_TYPE)
 479     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 480   if (TREE_CODE (mv2) != ARRAY_TYPE)
 481     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 482   target = composite_type (mv1, mv2);
 483   t1 = build_pointer_type (c_build_qualified_type
 484                            (target,
 485                             TYPE_QUALS (pointed_to_1) |
 486                             TYPE_QUALS (pointed_to_2)));
 487   return build_type_attribute_variant (t1, attributes);
 488 }
 489
 490 /* Return the common type for two arithmetic types under the usual
 491    arithmetic conversions.  The default conversions have already been
 492    applied, and enumerated types converted to their compatible integer
 493    types.  The resulting type is unqualified and has no attributes.
 494
 495    This is the type for the result of most arithmetic operations
 496    if the operands have the given two types.  */
 497
 498 static tree
 499 c_common_type (tree t1, tree t2)
 500 {
 501   enum tree_code code1;
 502   enum tree_code code2;
 503
 504   /* If one type is nonsense, use the other.  */
 505   if (t1 == error_mark_node)
 506     return t2;
 507   if (t2 == error_mark_node)
 508     return t1;
 509
 510   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 511     t1 = TYPE_MAIN_VARIANT (t1);
 512
 513   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 514     t2 = TYPE_MAIN_VARIANT (t2);
 515
 516   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 517     t1 = build_type_attribute_variant (t1, NULL_TREE);
 518
 519   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 520     t2 = build_type_attribute_variant (t2, NULL_TREE);
 521
 522   /* Save time if the two types are the same.  */
 523
 524   if (t1 == t2) return t1;
 525
 526   code1 = TREE_CODE (t1);
 527   code2 = TREE_CODE (t2);
 528
 529   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 530               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 531   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 532               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 533
 534   /* If one type is a vector type, return that type.  (How the usual
 535      arithmetic conversions apply to the vector types extension is not
 536      precisely specified.)  */
 537   if (code1 == VECTOR_TYPE)
 538     return t1;
 539
 540   if (code2 == VECTOR_TYPE)
 541     return t2;
 542
 543   /* If one type is complex, form the common type of the non-complex
 544      components, then make that complex.  Use T1 or T2 if it is the
 545      required type.  */
 546   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 547     {
 548       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 549       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 550       tree subtype = c_common_type (subtype1, subtype2);
 551
 552       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 553         return t1;
 554       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 555         return t2;
 556       else
 557         return build_complex_type (subtype);
 558     }
 559
 560   /* If only one is real, use it as the result.  */
 561
 562   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 563     return t1;
 564
 565   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 566     return t2;
 567
 568   /* Both real or both integers; use the one with greater precision.  */
 569
 570   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 571     return t1;
 572   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 573     return t2;
 574
 575   /* Same precision.  Prefer long longs to longs to ints when the
 576      same precision, following the C99 rules on integer type rank
 577      (which are equivalent to the C90 rules for C90 types).  */
 578
 579   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 580       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 581     return long_long_unsigned_type_node;
 582
 583   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 584       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 585     {
 586       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 587         return long_long_unsigned_type_node;
 588       else
 589         return long_long_integer_type_node;
 590     }
 591
 592   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 593       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 594     return long_unsigned_type_node;
 595
 596   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 597       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 598     {
 599       /* But preserve unsignedness from the other type,
 600          since long cannot hold all the values of an unsigned int.  */
 601       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 602         return long_unsigned_type_node;
 603       else
 604         return long_integer_type_node;
 605     }
 606
 607   /* Likewise, prefer long double to double even if same size.  */
 608   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 609       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 610     return long_double_type_node;
 611
 612   /* Otherwise prefer the unsigned one.  */
 613
 614   if (TYPE_UNSIGNED (t1))
 615     return t1;
 616   else
 617     return t2;
 618 }
 619 \f
 620 /* Wrapper around c_common_type that is used by c-common.c.  ENUMERAL_TYPEs
 621    are allowed here and are converted to their compatible integer types.  */
 622 tree
 623 common_type (tree t1, tree t2)
 624 {
 625   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 626     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 627   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 628     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 629   return c_common_type (t1, t2);
 630 }
 631 \f
 632 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 633    or various other operations.  Return 2 if they are compatible
 634    but a warning may be needed if you use them together.  */
 635
 636 int
 637 comptypes (tree type1, tree type2)
 638 {
 639   tree t1 = type1;
 640   tree t2 = type2;
 641   int attrval, val;
 642
 643   /* Suppress errors caused by previously reported errors.  */
 644
 645   if (t1 == t2 || !t1 || !t2
 646       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 647     return 1;
 648
 649   /* If either type is the internal version of sizetype, return the
 650      language version.  */
 651   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 652       && TYPE_ORIG_SIZE_TYPE (t1))
 653     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 654
 655   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 656       && TYPE_ORIG_SIZE_TYPE (t2))
 657     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 658
 659
 660   /* Enumerated types are compatible with integer types, but this is
 661      not transitive: two enumerated types in the same translation unit
 662      are compatible with each other only if they are the same type.  */
 663
 664   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 665     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 666   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 667     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 668
 669   if (t1 == t2)
 670     return 1;
 671
 672   /* Different classes of types can't be compatible.  */
 673
 674   if (TREE_CODE (t1) != TREE_CODE (t2))
 675     return 0;
 676
 677   /* Qualifiers must match. C99 6.7.3p9 */
 678
 679   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 680     return 0;
 681
 682   /* Allow for two different type nodes which have essentially the same
 683      definition.  Note that we already checked for equality of the type
 684      qualifiers (just above).  */
 685
 686   if (TREE_CODE (t1) != ARRAY_TYPE
 687       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 688     return 1;
 689
 690   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 691   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 692      return 0;
 693
 694   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 695   val = 0;
 696
 697   switch (TREE_CODE (t1))
 698     {
 699     case POINTER_TYPE:
 700       /* We must give ObjC the first crack at comparing pointers, since
 701            protocol qualifiers may be involved.  */
 702       if (c_dialect_objc () && (val = objc_comptypes (t1, t2, 0)) >= 0)
 703         break;
 704       /* Do not remove mode or aliasing information.  */
 705       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 706           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 707         break;
 708       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 709              ? 1 : comptypes (TREE_TYPE (t1), TREE_TYPE (t2)));
 710       break;
 711
 712     case FUNCTION_TYPE:
 713       val = function_types_compatible_p (t1, t2);
 714       break;
 715
 716     case ARRAY_TYPE:
 717       {
 718         tree d1 = TYPE_DOMAIN (t1);
 719         tree d2 = TYPE_DOMAIN (t2);
 720         bool d1_variable, d2_variable;
 721         bool d1_zero, d2_zero;
 722         val = 1;
 723
 724         /* Target types must match incl. qualifiers.  */
 725         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 726             && 0 == (val = comptypes (TREE_TYPE (t1), TREE_TYPE (t2))))
 727           return 0;
 728
 729         /* Sizes must match unless one is missing or variable.  */
 730         if (d1 == 0 || d2 == 0 || d1 == d2)
 731           break;
 732
 733         d1_zero = !TYPE_MAX_VALUE (d1);
 734         d2_zero = !TYPE_MAX_VALUE (d2);
 735
 736         d1_variable = (!d1_zero
 737                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 738                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 739         d2_variable = (!d2_zero
 740                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 741                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 742
 743         if (d1_variable || d2_variable)
 744           break;
 745         if (d1_zero && d2_zero)
 746           break;
 747         if (d1_zero || d2_zero
 748             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 749             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 750           val = 0;
 751
 752         break;
 753       }
 754
 755     case RECORD_TYPE:
 756       /* We are dealing with two distinct structs.  In assorted Objective-C
 757          corner cases, however, these can still be deemed equivalent.  */
 758       if (c_dialect_objc () && objc_comptypes (t1, t2, 0) == 1)
 759         val = 1;
 760
 761     case ENUMERAL_TYPE:
 762     case UNION_TYPE:
 763       if (val != 1 && !same_translation_unit_p (t1, t2))
 764         val = tagged_types_tu_compatible_p (t1, t2);
 765       break;
 766
 767     case VECTOR_TYPE:
 768       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 769             && comptypes (TREE_TYPE (t1), TREE_TYPE (t2));
 770       break;
 771
 772     default:
 773       break;
 774     }
 775   return attrval == 2 && val == 1 ? 2 : val;
 776 }
 777
 778 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 779    ignoring their qualifiers.  REFLEXIVE is only used by ObjC - set it
 780    to 1 or 0 depending if the check of the pointer types is meant to
 781    be reflexive or not (typically, assignments are not reflexive,
 782    while comparisons are reflexive).
 783 */
 784
 785 static int
 786 comp_target_types (tree ttl, tree ttr, int reflexive)
 787 {
 788   int val;
 789   tree mvl, mvr;
 790
 791   /* Give objc_comptypes a crack at letting these types through.  */
 792   if ((val = objc_comptypes (ttl, ttr, reflexive)) >= 0)
 793     return val;
 794
 795   /* Do not lose qualifiers on element types of array types that are
 796      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 797   mvl = TREE_TYPE (ttl);
 798   mvr = TREE_TYPE (ttr);
 799   if (TREE_CODE (mvl) != ARRAY_TYPE)
 800     mvl = TYPE_MAIN_VARIANT (mvl);
 801   if (TREE_CODE (mvr) != ARRAY_TYPE)
 802     mvr = TYPE_MAIN_VARIANT (mvr);
 803   val = comptypes (mvl, mvr);
 804
 805   if (val == 2 && pedantic)
 806     pedwarn ("types are not quite compatible");
 807   return val;
 808 }
 809 \f
 810 /* Subroutines of `comptypes'.  */
 811
 812 /* Determine whether two trees derive from the same translation unit.
 813    If the CONTEXT chain ends in a null, that tree's context is still
 814    being parsed, so if two trees have context chains ending in null,
 815    they're in the same translation unit.  */
 816 int
 817 same_translation_unit_p (tree t1, tree t2)
 818 {
 819   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 820     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 821       {
 822       case tcc_declaration:
 823         t1 = DECL_CONTEXT (t1); break;
 824       case tcc_type:
 825         t1 = TYPE_CONTEXT (t1); break;
 826       case tcc_exceptional:
 827         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 828       default: gcc_unreachable ();
 829       }
 830
 831   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 832     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 833       {
 834       case tcc_declaration:
 835         t2 = DECL_CONTEXT (t2); break;
 836       case tcc_type:
 837         t2 = TYPE_CONTEXT (t2); break;
 838       case tcc_exceptional:
 839         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 840       default: gcc_unreachable ();
 841       }
 842
 843   return t1 == t2;
 844 }
 845
 846 /* The C standard says that two structures in different translation
 847    units are compatible with each other only if the types of their
 848    fields are compatible (among other things).  So, consider two copies
 849    of this structure:  */
 850
 851 struct tagged_tu_seen {
 852   const struct tagged_tu_seen * next;
 853   tree t1;
 854   tree t2;
 855 };
 856
 857 /* Can they be compatible with each other?  We choose to break the
 858    recursion by allowing those types to be compatible.  */
 859
 860 static const struct tagged_tu_seen * tagged_tu_seen_base;
 861
 862 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 863    compatible.  If the two types are not the same (which has been
 864    checked earlier), this can only happen when multiple translation
 865    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 866    rules.  */
 867
 868 static int
 869 tagged_types_tu_compatible_p (tree t1, tree t2)
 870 {
 871   tree s1, s2;
 872   bool needs_warning = false;
 873
 874   /* We have to verify that the tags of the types are the same.  This
 875      is harder than it looks because this may be a typedef, so we have
 876      to go look at the original type.  It may even be a typedef of a
 877      typedef...
 878      In the case of compiler-created builtin structs the TYPE_DECL
 879      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 880   while (TYPE_NAME (t1)
 881          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 882          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 883     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 884
 885   while (TYPE_NAME (t2)
 886          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
 887          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
 888     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
 889
 890   /* C90 didn't have the requirement that the two tags be the same.  */
 891   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
 892     return 0;
 893
 894   /* C90 didn't say what happened if one or both of the types were
 895      incomplete; we choose to follow C99 rules here, which is that they
 896      are compatible.  */
 897   if (TYPE_SIZE (t1) == NULL
 898       || TYPE_SIZE (t2) == NULL)
 899     return 1;
 900
 901   {
 902     const struct tagged_tu_seen * tts_i;
 903     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
 904       if (tts_i->t1 == t1 && tts_i->t2 == t2)
 905         return 1;
 906   }
 907
 908   switch (TREE_CODE (t1))
 909     {
 910     case ENUMERAL_TYPE:
 911       {
 912
 913         /* Speed up the case where the type values are in the same order.  */
 914         tree tv1 = TYPE_VALUES (t1);
 915         tree tv2 = TYPE_VALUES (t2);
 916
 917         if (tv1 == tv2)
 918           return 1;
 919
 920         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
 921           {
 922             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
 923               break;
 924             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
 925               return 0;
 926           }
 927
 928         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
 929           return 1;
 930         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
 931           return 0;
 932
 933         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
 934           return 0;
 935
 936         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
 937           {
 938             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
 939             if (s2 == NULL
 940                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
 941               return 0;
 942           }
 943         return 1;
 944       }
 945
 946     case UNION_TYPE:
 947       {
 948         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
 949           return 0;
 950
 951         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
 952           {
 953             bool ok = false;
 954             struct tagged_tu_seen tts;
 955
 956             tts.next = tagged_tu_seen_base;
 957             tts.t1 = t1;
 958             tts.t2 = t2;
 959             tagged_tu_seen_base = &tts;
 960
 961             if (DECL_NAME (s1) != NULL)
 962               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
 963                 if (DECL_NAME (s1) == DECL_NAME (s2))
 964                   {
 965                     int result;
 966                     result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
 967                     if (result == 0)
 968                       break;
 969                     if (result == 2)
 970                       needs_warning = true;
 971
 972                     if (TREE_CODE (s1) == FIELD_DECL
 973                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
 974                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
 975                       break;
 976
 977                     ok = true;
 978                     break;
 979                   }
 980             tagged_tu_seen_base = tts.next;
 981             if (!ok)
 982               return 0;
 983           }
 984         return needs_warning ? 2 : 1;
 985       }
 986
 987     case RECORD_TYPE:
 988       {
 989         struct tagged_tu_seen tts;
 990
 991         tts.next = tagged_tu_seen_base;
 992         tts.t1 = t1;
 993         tts.t2 = t2;
 994         tagged_tu_seen_base = &tts;
 995
 996         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
 997              s1 && s2;
 998              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
 999           {
1000             int result;
1001             if (TREE_CODE (s1) != TREE_CODE (s2)
1002                 || DECL_NAME (s1) != DECL_NAME (s2))
1003               break;
1004             result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
1005             if (result == 0)
1006               break;
1007             if (result == 2)
1008               needs_warning = true;
1009
1010             if (TREE_CODE (s1) == FIELD_DECL
1011                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1012                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1013               break;
1014           }
1015         tagged_tu_seen_base = tts.next;
1016         if (s1 && s2)
1017           return 0;
1018         return needs_warning ? 2 : 1;
1019       }
1020
1021     default:
1022       gcc_unreachable ();
1023     }
1024 }
1025
1026 /* Return 1 if two function types F1 and F2 are compatible.
1027    If either type specifies no argument types,
1028    the other must specify a fixed number of self-promoting arg types.
1029    Otherwise, if one type specifies only the number of arguments,
1030    the other must specify that number of self-promoting arg types.
1031    Otherwise, the argument types must match.  */
1032
1033 static int
1034 function_types_compatible_p (tree f1, tree f2)
1035 {
1036   tree args1, args2;
1037   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1038   int val = 1;
1039   int val1;
1040   tree ret1, ret2;
1041
1042   ret1 = TREE_TYPE (f1);
1043   ret2 = TREE_TYPE (f2);
1044
1045   /* 'volatile' qualifiers on a function's return type used to mean
1046      the function is noreturn.  */
1047   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1048     pedwarn ("function return types not compatible due to %<volatile%>");
1049   if (TYPE_VOLATILE (ret1))
1050     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1051                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1052   if (TYPE_VOLATILE (ret2))
1053     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1054                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1055   val = comptypes (ret1, ret2);
1056   if (val == 0)
1057     return 0;
1058
1059   args1 = TYPE_ARG_TYPES (f1);
1060   args2 = TYPE_ARG_TYPES (f2);
1061
1062   /* An unspecified parmlist matches any specified parmlist
1063      whose argument types don't need default promotions.  */
1064
1065   if (args1 == 0)
1066     {
1067       if (!self_promoting_args_p (args2))
1068         return 0;
1069       /* If one of these types comes from a non-prototype fn definition,
1070          compare that with the other type's arglist.
1071          If they don't match, ask for a warning (0, but no error).  */
1072       if (TYPE_ACTUAL_ARG_TYPES (f1)
1073           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1074         val = 2;
1075       return val;
1076     }
1077   if (args2 == 0)
1078     {
1079       if (!self_promoting_args_p (args1))
1080         return 0;
1081       if (TYPE_ACTUAL_ARG_TYPES (f2)
1082           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1083         val = 2;
1084       return val;
1085     }
1086
1087   /* Both types have argument lists: compare them and propagate results.  */
1088   val1 = type_lists_compatible_p (args1, args2);
1089   return val1 != 1 ? val1 : val;
1090 }
1091
1092 /* Check two lists of types for compatibility,
1093    returning 0 for incompatible, 1 for compatible,
1094    or 2 for compatible with warning.  */
1095
1096 static int
1097 type_lists_compatible_p (tree args1, tree args2)
1098 {
1099   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1100   int val = 1;
1101   int newval = 0;
1102
1103   while (1)
1104     {
1105       tree a1, mv1, a2, mv2;
1106       if (args1 == 0 && args2 == 0)
1107         return val;
1108       /* If one list is shorter than the other,
1109          they fail to match.  */
1110       if (args1 == 0 || args2 == 0)
1111         return 0;
1112       mv1 = a1 = TREE_VALUE (args1);
1113       mv2 = a2 = TREE_VALUE (args2);
1114       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1115         mv1 = TYPE_MAIN_VARIANT (mv1);
1116       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1117         mv2 = TYPE_MAIN_VARIANT (mv2);
1118       /* A null pointer instead of a type
1119          means there is supposed to be an argument
1120          but nothing is specified about what type it has.
1121          So match anything that self-promotes.  */
1122       if (a1 == 0)
1123         {
1124           if (c_type_promotes_to (a2) != a2)
1125             return 0;
1126         }
1127       else if (a2 == 0)
1128         {
1129           if (c_type_promotes_to (a1) != a1)
1130             return 0;
1131         }
1132       /* If one of the lists has an error marker, ignore this arg.  */
1133       else if (TREE_CODE (a1) == ERROR_MARK
1134                || TREE_CODE (a2) == ERROR_MARK)
1135         ;
1136       else if (!(newval = comptypes (mv1, mv2)))
1137         {
1138           /* Allow  wait (union {union wait *u; int *i} *)
1139              and  wait (union wait *)  to be compatible.  */
1140           if (TREE_CODE (a1) == UNION_TYPE
1141               && (TYPE_NAME (a1) == 0
1142                   || TYPE_TRANSPARENT_UNION (a1))
1143               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1144               && tree_int_cst_equal (TYPE_SIZE (a1),
1145                                      TYPE_SIZE (a2)))
1146             {
1147               tree memb;
1148               for (memb = TYPE_FIELDS (a1);
1149                    memb; memb = TREE_CHAIN (memb))
1150                 {
1151                   tree mv3 = TREE_TYPE (memb);
1152                   if (mv3 && mv3 != error_mark_node
1153                       && TREE_CODE (mv3) != ARRAY_TYPE)
1154                     mv3 = TYPE_MAIN_VARIANT (mv3);
1155                   if (comptypes (mv3, mv2))
1156                     break;
1157                 }
1158               if (memb == 0)
1159                 return 0;
1160             }
1161           else if (TREE_CODE (a2) == UNION_TYPE
1162                    && (TYPE_NAME (a2) == 0
1163                        || TYPE_TRANSPARENT_UNION (a2))
1164                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1165                    && tree_int_cst_equal (TYPE_SIZE (a2),
1166                                           TYPE_SIZE (a1)))
1167             {
1168               tree memb;
1169               for (memb = TYPE_FIELDS (a2);
1170                    memb; memb = TREE_CHAIN (memb))
1171                 {
1172                   tree mv3 = TREE_TYPE (memb);
1173                   if (mv3 && mv3 != error_mark_node
1174                       && TREE_CODE (mv3) != ARRAY_TYPE)
1175                     mv3 = TYPE_MAIN_VARIANT (mv3);
1176                   if (comptypes (mv3, mv1))
1177                     break;
1178                 }
1179               if (memb == 0)
1180                 return 0;
1181             }
1182           else
1183             return 0;
1184         }
1185
1186       /* comptypes said ok, but record if it said to warn.  */
1187       if (newval > val)
1188         val = newval;
1189
1190       args1 = TREE_CHAIN (args1);
1191       args2 = TREE_CHAIN (args2);
1192     }
1193 }
1194 \f
1195 /* Compute the size to increment a pointer by.  */
1196
1197 static tree
1198 c_size_in_bytes (tree type)
1199 {
1200   enum tree_code code = TREE_CODE (type);
1201
1202   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1203     return size_one_node;
1204
1205   if (!COMPLETE_OR_VOID_TYPE_P (type))
1206     {
1207       error ("arithmetic on pointer to an incomplete type");
1208       return size_one_node;
1209     }
1210
1211   /* Convert in case a char is more than one unit.  */
1212   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1213                      size_int (TYPE_PRECISION (char_type_node)
1214                                / BITS_PER_UNIT));
1215 }
1216 \f
1217 /* Return either DECL or its known constant value (if it has one).  */
1218
1219 tree
1220 decl_constant_value (tree decl)
1221 {
1222   if (/* Don't change a variable array bound or initial value to a constant
1223          in a place where a variable is invalid.  Note that DECL_INITIAL
1224          isn't valid for a PARM_DECL.  */
1225       current_function_decl != 0
1226       && TREE_CODE (decl) != PARM_DECL
1227       && !TREE_THIS_VOLATILE (decl)
1228       && TREE_READONLY (decl)
1229       && DECL_INITIAL (decl) != 0
1230       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1231       /* This is invalid if initial value is not constant.
1232          If it has either a function call, a memory reference,
1233          or a variable, then re-evaluating it could give different results.  */
1234       && TREE_CONSTANT (DECL_INITIAL (decl))
1235       /* Check for cases where this is sub-optimal, even though valid.  */
1236       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1237     return DECL_INITIAL (decl);
1238   return decl;
1239 }
1240
1241 /* Return either DECL or its known constant value (if it has one), but
1242    return DECL if pedantic or DECL has mode BLKmode.  This is for
1243    bug-compatibility with the old behavior of decl_constant_value
1244    (before GCC 3.0); every use of this function is a bug and it should
1245    be removed before GCC 3.1.  It is not appropriate to use pedantic
1246    in a way that affects optimization, and BLKmode is probably not the
1247    right test for avoiding misoptimizations either.  */
1248
1249 static tree
1250 decl_constant_value_for_broken_optimization (tree decl)
1251 {
1252   if (pedantic || DECL_MODE (decl) == BLKmode)
1253     return decl;
1254   else
1255     return decl_constant_value (decl);
1256 }
1257
1258
1259 /* Perform the default conversion of arrays and functions to pointers.
1260    Return the result of converting EXP.  For any other expression, just
1261    return EXP.  */
1262
1263 static tree
1264 default_function_array_conversion (tree exp)
1265 {
1266   tree orig_exp;
1267   tree type = TREE_TYPE (exp);
1268   enum tree_code code = TREE_CODE (type);
1269   int not_lvalue = 0;
1270
1271   /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1272      an lvalue.
1273
1274      Do not use STRIP_NOPS here!  It will remove conversions from pointer
1275      to integer and cause infinite recursion.  */
1276   orig_exp = exp;
1277   while (TREE_CODE (exp) == NON_LVALUE_EXPR
1278          || (TREE_CODE (exp) == NOP_EXPR
1279              && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
1280     {
1281       if (TREE_CODE (exp) == NON_LVALUE_EXPR)
1282         not_lvalue = 1;
1283       exp = TREE_OPERAND (exp, 0);
1284     }
1285
1286   if (TREE_NO_WARNING (orig_exp))
1287     TREE_NO_WARNING (exp) = 1;
1288
1289   if (code == FUNCTION_TYPE)
1290     {
1291       return build_unary_op (ADDR_EXPR, exp, 0);
1292     }
1293   if (code == ARRAY_TYPE)
1294     {
1295       tree adr;
1296       tree restype = TREE_TYPE (type);
1297       tree ptrtype;
1298       int constp = 0;
1299       int volatilep = 0;
1300       int lvalue_array_p;
1301
1302       if (REFERENCE_CLASS_P (exp) || DECL_P (exp))
1303         {
1304           constp = TREE_READONLY (exp);
1305           volatilep = TREE_THIS_VOLATILE (exp);
1306         }
1307
1308       if (TYPE_QUALS (type) || constp || volatilep)
1309         restype
1310           = c_build_qualified_type (restype,
1311                                     TYPE_QUALS (type)
1312                                     | (constp * TYPE_QUAL_CONST)
1313                                     | (volatilep * TYPE_QUAL_VOLATILE));
1314
1315       if (TREE_CODE (exp) == INDIRECT_REF)
1316         return convert (build_pointer_type (restype),
1317                         TREE_OPERAND (exp, 0));
1318
1319       if (TREE_CODE (exp) == COMPOUND_EXPR)
1320         {
1321           tree op1 = default_conversion (TREE_OPERAND (exp, 1));
1322           return build2 (COMPOUND_EXPR, TREE_TYPE (op1),
1323                          TREE_OPERAND (exp, 0), op1);
1324         }
1325
1326       lvalue_array_p = !not_lvalue && lvalue_p (exp);
1327       if (!flag_isoc99 && !lvalue_array_p)
1328         {
1329           /* Before C99, non-lvalue arrays do not decay to pointers.
1330              Normally, using such an array would be invalid; but it can
1331              be used correctly inside sizeof or as a statement expression.
1332              Thus, do not give an error here; an error will result later.  */
1333           return exp;
1334         }
1335
1336       ptrtype = build_pointer_type (restype);
1337
1338       if (TREE_CODE (exp) == VAR_DECL)
1339         {
1340           /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1341              ADDR_EXPR because it's the best way of representing what
1342              happens in C when we take the address of an array and place
1343              it in a pointer to the element type.  */
1344           adr = build1 (ADDR_EXPR, ptrtype, exp);
1345           if (!c_mark_addressable (exp))
1346             return error_mark_node;
1347           TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1348           return adr;
1349         }
1350       /* This way is better for a COMPONENT_REF since it can
1351          simplify the offset for a component.  */
1352       adr = build_unary_op (ADDR_EXPR, exp, 1);
1353       return convert (ptrtype, adr);
1354     }
1355   return exp;
1356 }
1357
1358
1359 /* EXP is an expression of integer type.  Apply the integer promotions
1360    to it and return the promoted value.  */
1361
1362 tree
1363 perform_integral_promotions (tree exp)
1364 {
1365   tree type = TREE_TYPE (exp);
1366   enum tree_code code = TREE_CODE (type);
1367
1368   gcc_assert (INTEGRAL_TYPE_P (type));
1369
1370   /* Normally convert enums to int,
1371      but convert wide enums to something wider.  */
1372   if (code == ENUMERAL_TYPE)
1373     {
1374       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1375                                           TYPE_PRECISION (integer_type_node)),
1376                                      ((TYPE_PRECISION (type)
1377                                        >= TYPE_PRECISION (integer_type_node))
1378                                       && TYPE_UNSIGNED (type)));
1379
1380       return convert (type, exp);
1381     }
1382
1383   /* ??? This should no longer be needed now bit-fields have their
1384      proper types.  */
1385   if (TREE_CODE (exp) == COMPONENT_REF
1386       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1387       /* If it's thinner than an int, promote it like a
1388          c_promoting_integer_type_p, otherwise leave it alone.  */
1389       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1390                                TYPE_PRECISION (integer_type_node)))
1391     return convert (integer_type_node, exp);
1392
1393   if (c_promoting_integer_type_p (type))
1394     {
1395       /* Preserve unsignedness if not really getting any wider.  */
1396       if (TYPE_UNSIGNED (type)
1397           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1398         return convert (unsigned_type_node, exp);
1399
1400       return convert (integer_type_node, exp);
1401     }
1402
1403   return exp;
1404 }
1405
1406
1407 /* Perform default promotions for C data used in expressions.
1408    Arrays and functions are converted to pointers;
1409    enumeral types or short or char, to int.
1410    In addition, manifest constants symbols are replaced by their values.  */
1411
1412 tree
1413 default_conversion (tree exp)
1414 {
1415   tree orig_exp;
1416   tree type = TREE_TYPE (exp);
1417   enum tree_code code = TREE_CODE (type);
1418
1419   if (code == FUNCTION_TYPE || code == ARRAY_TYPE)
1420     return default_function_array_conversion (exp);
1421
1422   /* Constants can be used directly unless they're not loadable.  */
1423   if (TREE_CODE (exp) == CONST_DECL)
1424     exp = DECL_INITIAL (exp);
1425
1426   /* Replace a nonvolatile const static variable with its value unless
1427      it is an array, in which case we must be sure that taking the
1428      address of the array produces consistent results.  */
1429   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1430     {
1431       exp = decl_constant_value_for_broken_optimization (exp);
1432       type = TREE_TYPE (exp);
1433     }
1434
1435   /* Strip no-op conversions.  */
1436   orig_exp = exp;
1437   STRIP_TYPE_NOPS (exp);
1438
1439   if (TREE_NO_WARNING (orig_exp))
1440     TREE_NO_WARNING (exp) = 1;
1441
1442   if (INTEGRAL_TYPE_P (type))
1443     return perform_integral_promotions (exp);
1444
1445   if (code == VOID_TYPE)
1446     {
1447       error ("void value not ignored as it ought to be");
1448       return error_mark_node;
1449     }
1450   return exp;
1451 }
1452 \f
1453 /* Look up COMPONENT in a structure or union DECL.
1454
1455    If the component name is not found, returns NULL_TREE.  Otherwise,
1456    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1457    stepping down the chain to the component, which is in the last
1458    TREE_VALUE of the list.  Normally the list is of length one, but if
1459    the component is embedded within (nested) anonymous structures or
1460    unions, the list steps down the chain to the component.  */
1461
1462 static tree
1463 lookup_field (tree decl, tree component)
1464 {
1465   tree type = TREE_TYPE (decl);
1466   tree field;
1467
1468   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1469      to the field elements.  Use a binary search on this array to quickly
1470      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1471      will always be set for structures which have many elements.  */
1472
1473   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1474     {
1475       int bot, top, half;
1476       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1477
1478       field = TYPE_FIELDS (type);
1479       bot = 0;
1480       top = TYPE_LANG_SPECIFIC (type)->s->len;
1481       while (top - bot > 1)
1482         {
1483           half = (top - bot + 1) >> 1;
1484           field = field_array[bot+half];
1485
1486           if (DECL_NAME (field) == NULL_TREE)
1487             {
1488               /* Step through all anon unions in linear fashion.  */
1489               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1490                 {
1491                   field = field_array[bot++];
1492                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1493                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1494                     {
1495                       tree anon = lookup_field (field, component);
1496
1497                       if (anon)
1498                         return tree_cons (NULL_TREE, field, anon);
1499                     }
1500                 }
1501
1502               /* Entire record is only anon unions.  */
1503               if (bot > top)
1504                 return NULL_TREE;
1505
1506               /* Restart the binary search, with new lower bound.  */
1507               continue;
1508             }
1509
1510           if (DECL_NAME (field) == component)
1511             break;
1512           if (DECL_NAME (field) < component)
1513             bot += half;
1514           else
1515             top = bot + half;
1516         }
1517
1518       if (DECL_NAME (field_array[bot]) == component)
1519         field = field_array[bot];
1520       else if (DECL_NAME (field) != component)
1521         return NULL_TREE;
1522     }
1523   else
1524     {
1525       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1526         {
1527           if (DECL_NAME (field) == NULL_TREE
1528               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1529                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1530             {
1531               tree anon = lookup_field (field, component);
1532
1533               if (anon)
1534                 return tree_cons (NULL_TREE, field, anon);
1535             }
1536
1537           if (DECL_NAME (field) == component)
1538             break;
1539         }
1540
1541       if (field == NULL_TREE)
1542         return NULL_TREE;
1543     }
1544
1545   return tree_cons (NULL_TREE, field, NULL_TREE);
1546 }
1547
1548 /* Make an expression to refer to the COMPONENT field of
1549    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1550
1551 tree
1552 build_component_ref (tree datum, tree component)
1553 {
1554   tree type = TREE_TYPE (datum);
1555   enum tree_code code = TREE_CODE (type);
1556   tree field = NULL;
1557   tree ref;
1558
1559   if (!objc_is_public (datum, component))
1560     return error_mark_node;
1561
1562   /* See if there is a field or component with name COMPONENT.  */
1563
1564   if (code == RECORD_TYPE || code == UNION_TYPE)
1565     {
1566       if (!COMPLETE_TYPE_P (type))
1567         {
1568           c_incomplete_type_error (NULL_TREE, type);
1569           return error_mark_node;
1570         }
1571
1572       field = lookup_field (datum, component);
1573
1574       if (!field)
1575         {
1576           error ("%qT has no member named %qE", type, component);
1577           return error_mark_node;
1578         }
1579
1580       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1581          This might be better solved in future the way the C++ front
1582          end does it - by giving the anonymous entities each a
1583          separate name and type, and then have build_component_ref
1584          recursively call itself.  We can't do that here.  */
1585       do
1586         {
1587           tree subdatum = TREE_VALUE (field);
1588
1589           if (TREE_TYPE (subdatum) == error_mark_node)
1590             return error_mark_node;
1591
1592           ref = build3 (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1593                         NULL_TREE);
1594           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1595             TREE_READONLY (ref) = 1;
1596           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1597             TREE_THIS_VOLATILE (ref) = 1;
1598
1599           if (TREE_DEPRECATED (subdatum))
1600             warn_deprecated_use (subdatum);
1601
1602           datum = ref;
1603
1604           field = TREE_CHAIN (field);
1605         }
1606       while (field);
1607
1608       return ref;
1609     }
1610   else if (code != ERROR_MARK)
1611     error ("request for member %qE in something not a structure or union",
1612            component);
1613
1614   return error_mark_node;
1615 }
1616 \f
1617 /* Given an expression PTR for a pointer, return an expression
1618    for the value pointed to.
1619    ERRORSTRING is the name of the operator to appear in error messages.  */
1620
1621 tree
1622 build_indirect_ref (tree ptr, const char *errorstring)
1623 {
1624   tree pointer = default_conversion (ptr);
1625   tree type = TREE_TYPE (pointer);
1626
1627   if (TREE_CODE (type) == POINTER_TYPE)
1628     {
1629       if (TREE_CODE (pointer) == ADDR_EXPR
1630           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1631               == TREE_TYPE (type)))
1632         return TREE_OPERAND (pointer, 0);
1633       else
1634         {
1635           tree t = TREE_TYPE (type);
1636           tree mvt = t;
1637           tree ref;
1638
1639           if (TREE_CODE (mvt) != ARRAY_TYPE)
1640             mvt = TYPE_MAIN_VARIANT (mvt);
1641           ref = build1 (INDIRECT_REF, mvt, pointer);
1642
1643           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1644             {
1645               error ("dereferencing pointer to incomplete type");
1646               return error_mark_node;
1647             }
1648           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1649             warning (0, "dereferencing %<void *%> pointer");
1650
1651           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1652              so that we get the proper error message if the result is used
1653              to assign to.  Also, &* is supposed to be a no-op.
1654              And ANSI C seems to specify that the type of the result
1655              should be the const type.  */
1656           /* A de-reference of a pointer to const is not a const.  It is valid
1657              to change it via some other pointer.  */
1658           TREE_READONLY (ref) = TYPE_READONLY (t);
1659           TREE_SIDE_EFFECTS (ref)
1660             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1661           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1662           return ref;
1663         }
1664     }
1665   else if (TREE_CODE (pointer) != ERROR_MARK)
1666     error ("invalid type argument of %qs", errorstring);
1667   return error_mark_node;
1668 }
1669
1670 /* This handles expressions of the form "a[i]", which denotes
1671    an array reference.
1672
1673    This is logically equivalent in C to *(a+i), but we may do it differently.
1674    If A is a variable or a member, we generate a primitive ARRAY_REF.
1675    This avoids forcing the array out of registers, and can work on
1676    arrays that are not lvalues (for example, members of structures returned
1677    by functions).  */
1678
1679 tree
1680 build_array_ref (tree array, tree index)
1681 {
1682   bool swapped = false;
1683   if (TREE_TYPE (array) == error_mark_node
1684       || TREE_TYPE (index) == error_mark_node)
1685     return error_mark_node;
1686
1687   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1688       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1689     {
1690       tree temp;
1691       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1692           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1693         {
1694           error ("subscripted value is neither array nor pointer");
1695           return error_mark_node;
1696         }
1697       temp = array;
1698       array = index;
1699       index = temp;
1700       swapped = true;
1701     }
1702
1703   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1704     {
1705       error ("array subscript is not an integer");
1706       return error_mark_node;
1707     }
1708
1709   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1710     {
1711       error ("subscripted value is pointer to function");
1712       return error_mark_node;
1713     }
1714
1715   /* Subscripting with type char is likely to lose on a machine where
1716      chars are signed.  So warn on any machine, but optionally.  Don't
1717      warn for unsigned char since that type is safe.  Don't warn for
1718      signed char because anyone who uses that must have done so
1719      deliberately.  ??? Existing practice has also been to warn only
1720      when the char index is syntactically the index, not for
1721      char[array].  */
1722   if (warn_char_subscripts && !swapped
1723       && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1724     warning (0, "array subscript has type %<char%>");
1725
1726   /* Apply default promotions *after* noticing character types.  */
1727   index = default_conversion (index);
1728
1729   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1730
1731   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1732     {
1733       tree rval, type;
1734
1735       /* An array that is indexed by a non-constant
1736          cannot be stored in a register; we must be able to do
1737          address arithmetic on its address.
1738          Likewise an array of elements of variable size.  */
1739       if (TREE_CODE (index) != INTEGER_CST
1740           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1741               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1742         {
1743           if (!c_mark_addressable (array))
1744             return error_mark_node;
1745         }
1746       /* An array that is indexed by a constant value which is not within
1747          the array bounds cannot be stored in a register either; because we
1748          would get a crash in store_bit_field/extract_bit_field when trying
1749          to access a non-existent part of the register.  */
1750       if (TREE_CODE (index) == INTEGER_CST
1751           && TYPE_DOMAIN (TREE_TYPE (array))
1752           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1753         {
1754           if (!c_mark_addressable (array))
1755             return error_mark_node;
1756         }
1757
1758       if (pedantic)
1759         {
1760           tree foo = array;
1761           while (TREE_CODE (foo) == COMPONENT_REF)
1762             foo = TREE_OPERAND (foo, 0);
1763           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1764             pedwarn ("ISO C forbids subscripting %<register%> array");
1765           else if (!flag_isoc99 && !lvalue_p (foo))
1766             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1767         }
1768
1769       type = TREE_TYPE (TREE_TYPE (array));
1770       if (TREE_CODE (type) != ARRAY_TYPE)
1771         type = TYPE_MAIN_VARIANT (type);
1772       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1773       /* Array ref is const/volatile if the array elements are
1774          or if the array is.  */
1775       TREE_READONLY (rval)
1776         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1777             | TREE_READONLY (array));
1778       TREE_SIDE_EFFECTS (rval)
1779         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1780             | TREE_SIDE_EFFECTS (array));
1781       TREE_THIS_VOLATILE (rval)
1782         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1783             /* This was added by rms on 16 Nov 91.
1784                It fixes  vol struct foo *a;  a->elts[1]
1785                in an inline function.
1786                Hope it doesn't break something else.  */
1787             | TREE_THIS_VOLATILE (array));
1788       return require_complete_type (fold (rval));
1789     }
1790   else
1791     {
1792       tree ar = default_conversion (array);
1793
1794       if (ar == error_mark_node)
1795         return ar;
1796
1797       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1798       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1799
1800       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1801                                  "array indexing");
1802     }
1803 }
1804 \f
1805 /* Build an external reference to identifier ID.  FUN indicates
1806    whether this will be used for a function call.  LOC is the source
1807    location of the identifier.  */
1808 tree
1809 build_external_ref (tree id, int fun, location_t loc)
1810 {
1811   tree ref;
1812   tree decl = lookup_name (id);
1813
1814   /* In Objective-C, an instance variable (ivar) may be preferred to
1815      whatever lookup_name() found.  */
1816   decl = objc_lookup_ivar (decl, id);
1817
1818   if (decl && decl != error_mark_node)
1819     ref = decl;
1820   else if (fun)
1821     /* Implicit function declaration.  */
1822     ref = implicitly_declare (id);
1823   else if (decl == error_mark_node)
1824     /* Don't complain about something that's already been
1825        complained about.  */
1826     return error_mark_node;
1827   else
1828     {
1829       undeclared_variable (id, loc);
1830       return error_mark_node;
1831     }
1832
1833   if (TREE_TYPE (ref) == error_mark_node)
1834     return error_mark_node;
1835
1836   if (TREE_DEPRECATED (ref))
1837     warn_deprecated_use (ref);
1838
1839   if (!skip_evaluation)
1840     assemble_external (ref);
1841   TREE_USED (ref) = 1;
1842
1843   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
1844     {
1845       if (!in_sizeof && !in_typeof)
1846         C_DECL_USED (ref) = 1;
1847       else if (DECL_INITIAL (ref) == 0
1848                && DECL_EXTERNAL (ref)
1849                && !TREE_PUBLIC (ref))
1850         record_maybe_used_decl (ref);
1851     }
1852
1853   if (TREE_CODE (ref) == CONST_DECL)
1854     {
1855       ref = DECL_INITIAL (ref);
1856       TREE_CONSTANT (ref) = 1;
1857       TREE_INVARIANT (ref) = 1;
1858     }
1859   else if (current_function_decl != 0
1860            && !DECL_FILE_SCOPE_P (current_function_decl)
1861            && (TREE_CODE (ref) == VAR_DECL
1862                || TREE_CODE (ref) == PARM_DECL
1863                || TREE_CODE (ref) == FUNCTION_DECL))
1864     {
1865       tree context = decl_function_context (ref);
1866
1867       if (context != 0 && context != current_function_decl)
1868         DECL_NONLOCAL (ref) = 1;
1869     }
1870
1871   return ref;
1872 }
1873
1874 /* Record details of decls possibly used inside sizeof or typeof.  */
1875 struct maybe_used_decl
1876 {
1877   /* The decl.  */
1878   tree decl;
1879   /* The level seen at (in_sizeof + in_typeof).  */
1880   int level;
1881   /* The next one at this level or above, or NULL.  */
1882   struct maybe_used_decl *next;
1883 };
1884
1885 static struct maybe_used_decl *maybe_used_decls;
1886
1887 /* Record that DECL, an undefined static function reference seen
1888    inside sizeof or typeof, might be used if the operand of sizeof is
1889    a VLA type or the operand of typeof is a variably modified
1890    type.  */
1891
1892 static void
1893 record_maybe_used_decl (tree decl)
1894 {
1895   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
1896   t->decl = decl;
1897   t->level = in_sizeof + in_typeof;
1898   t->next = maybe_used_decls;
1899   maybe_used_decls = t;
1900 }
1901
1902 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
1903    USED is false, just discard them.  If it is true, mark them used
1904    (if no longer inside sizeof or typeof) or move them to the next
1905    level up (if still inside sizeof or typeof).  */
1906
1907 void
1908 pop_maybe_used (bool used)
1909 {
1910   struct maybe_used_decl *p = maybe_used_decls;
1911   int cur_level = in_sizeof + in_typeof;
1912   while (p && p->level > cur_level)
1913     {
1914       if (used)
1915         {
1916           if (cur_level == 0)
1917             C_DECL_USED (p->decl) = 1;
1918           else
1919             p->level = cur_level;
1920         }
1921       p = p->next;
1922     }
1923   if (!used || cur_level == 0)
1924     maybe_used_decls = p;
1925 }
1926
1927 /* Return the result of sizeof applied to EXPR.  */
1928
1929 struct c_expr
1930 c_expr_sizeof_expr (struct c_expr expr)
1931 {
1932   struct c_expr ret;
1933   if (expr.value == error_mark_node)
1934     {
1935       ret.value = error_mark_node;
1936       ret.original_code = ERROR_MARK;
1937       pop_maybe_used (false);
1938     }
1939   else
1940     {
1941       ret.value = c_sizeof (TREE_TYPE (expr.value));
1942       ret.original_code = ERROR_MARK;
1943       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
1944     }
1945   return ret;
1946 }
1947
1948 /* Return the result of sizeof applied to T, a structure for the type
1949    name passed to sizeof (rather than the type itself).  */
1950
1951 struct c_expr
1952 c_expr_sizeof_type (struct c_type_name *t)
1953 {
1954   tree type;
1955   struct c_expr ret;
1956   type = groktypename (t);
1957   ret.value = c_sizeof (type);
1958   ret.original_code = ERROR_MARK;
1959   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
1960   return ret;
1961 }
1962
1963 /* Build a function call to function FUNCTION with parameters PARAMS.
1964    PARAMS is a list--a chain of TREE_LIST nodes--in which the
1965    TREE_VALUE of each node is a parameter-expression.
1966    FUNCTION's data type may be a function type or a pointer-to-function.  */
1967
1968 tree
1969 build_function_call (tree function, tree params)
1970 {
1971   tree fntype, fundecl = 0;
1972   tree coerced_params;
1973   tree name = NULL_TREE, result;
1974   tree tem;
1975
1976   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
1977   STRIP_TYPE_NOPS (function);
1978
1979   /* Convert anything with function type to a pointer-to-function.  */
1980   if (TREE_CODE (function) == FUNCTION_DECL)
1981     {
1982       /* Implement type-directed function overloading for builtins.
1983          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
1984          handle all the type checking.  The result is a complete expression
1985          that implements this function call.  */
1986       tem = resolve_overloaded_builtin (function, params);
1987       if (tem)
1988         return tem;
1989
1990       name = DECL_NAME (function);
1991
1992       /* Differs from default_conversion by not setting TREE_ADDRESSABLE
1993          (because calling an inline function does not mean the function
1994          needs to be separately compiled).  */
1995       fntype = build_type_variant (TREE_TYPE (function),
1996                                    TREE_READONLY (function),
1997                                    TREE_THIS_VOLATILE (function));
1998       fundecl = function;
1999       function = build1 (ADDR_EXPR, build_pointer_type (fntype), function);
2000     }
2001   else
2002     function = default_conversion (function);
2003
2004   fntype = TREE_TYPE (function);
2005
2006   if (TREE_CODE (fntype) == ERROR_MARK)
2007     return error_mark_node;
2008
2009   if (!(TREE_CODE (fntype) == POINTER_TYPE
2010         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2011     {
2012       error ("called object %qE is not a function", function);
2013       return error_mark_node;
2014     }
2015
2016   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2017     current_function_returns_abnormally = 1;
2018
2019   /* fntype now gets the type of function pointed to.  */
2020   fntype = TREE_TYPE (fntype);
2021
2022   /* Check that the function is called through a compatible prototype.
2023      If it is not, replace the call by a trap, wrapped up in a compound
2024      expression if necessary.  This has the nice side-effect to prevent
2025      the tree-inliner from generating invalid assignment trees which may
2026      blow up in the RTL expander later.
2027
2028      ??? This doesn't work for Objective-C because objc_comptypes
2029      refuses to compare function prototypes, yet the compiler appears
2030      to build calls that are flagged as invalid by C's comptypes.  */
2031   if (!c_dialect_objc ()
2032       && TREE_CODE (function) == NOP_EXPR
2033       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2034       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2035       && !comptypes (fntype, TREE_TYPE (tem)))
2036     {
2037       tree return_type = TREE_TYPE (fntype);
2038       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2039                                        NULL_TREE);
2040
2041       /* This situation leads to run-time undefined behavior.  We can't,
2042          therefore, simply error unless we can prove that all possible
2043          executions of the program must execute the code.  */
2044       warning (0, "function called through a non-compatible type");
2045
2046       /* We can, however, treat "undefined" any way we please.
2047          Call abort to encourage the user to fix the program.  */
2048       inform ("if this code is reached, the program will abort");
2049
2050       if (VOID_TYPE_P (return_type))
2051         return trap;
2052       else
2053         {
2054           tree rhs;
2055
2056           if (AGGREGATE_TYPE_P (return_type))
2057             rhs = build_compound_literal (return_type,
2058                                           build_constructor (return_type,
2059                                                              NULL_TREE));
2060           else
2061             rhs = fold (build1 (NOP_EXPR, return_type, integer_zero_node));
2062
2063           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2064         }
2065     }
2066
2067   /* Convert the parameters to the types declared in the
2068      function prototype, or apply default promotions.  */
2069
2070   coerced_params
2071     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2072
2073   if (coerced_params == error_mark_node)
2074     return error_mark_node;
2075
2076   /* Check that the arguments to the function are valid.  */
2077
2078   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params);
2079
2080   result = build3 (CALL_EXPR, TREE_TYPE (fntype),
2081                    function, coerced_params, NULL_TREE);
2082   TREE_SIDE_EFFECTS (result) = 1;
2083
2084   if (require_constant_value)
2085     {
2086       result = fold_initializer (result);
2087
2088       if (TREE_CONSTANT (result)
2089           && (name == NULL_TREE
2090               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2091         pedwarn_init ("initializer element is not constant");
2092     }
2093   else
2094     result = fold (result);
2095
2096   if (VOID_TYPE_P (TREE_TYPE (result)))
2097     return result;
2098   return require_complete_type (result);
2099 }
2100 \f
2101 /* Convert the argument expressions in the list VALUES
2102    to the types in the list TYPELIST.  The result is a list of converted
2103    argument expressions, unless there are too few arguments in which
2104    case it is error_mark_node.
2105
2106    If TYPELIST is exhausted, or when an element has NULL as its type,
2107    perform the default conversions.
2108
2109    PARMLIST is the chain of parm decls for the function being called.
2110    It may be 0, if that info is not available.
2111    It is used only for generating error messages.
2112
2113    FUNCTION is a tree for the called function.  It is used only for
2114    error messages, where it is formatted with %qE.
2115
2116    This is also where warnings about wrong number of args are generated.
2117
2118    Both VALUES and the returned value are chains of TREE_LIST nodes
2119    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2120
2121 static tree
2122 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2123 {
2124   tree typetail, valtail;
2125   tree result = NULL;
2126   int parmnum;
2127   tree selector;
2128
2129   /* Change pointer to function to the function itself for
2130      diagnostics.  */
2131   if (TREE_CODE (function) == ADDR_EXPR
2132       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2133     function = TREE_OPERAND (function, 0);
2134
2135   /* Handle an ObjC selector specially for diagnostics.  */
2136   selector = objc_message_selector ();
2137
2138   /* Scan the given expressions and types, producing individual
2139      converted arguments and pushing them on RESULT in reverse order.  */
2140
2141   for (valtail = values, typetail = typelist, parmnum = 0;
2142        valtail;
2143        valtail = TREE_CHAIN (valtail), parmnum++)
2144     {
2145       tree type = typetail ? TREE_VALUE (typetail) : 0;
2146       tree val = TREE_VALUE (valtail);
2147       tree rname = function;
2148       int argnum = parmnum + 1;
2149       const char *invalid_func_diag;
2150
2151       if (type == void_type_node)
2152         {
2153           error ("too many arguments to function %qE", function);
2154           break;
2155         }
2156
2157       if (selector && argnum > 2)
2158         {
2159           rname = selector;
2160           argnum -= 2;
2161         }
2162
2163       STRIP_TYPE_NOPS (val);
2164
2165       val = default_function_array_conversion (val);
2166
2167       val = require_complete_type (val);
2168
2169       if (type != 0)
2170         {
2171           /* Formal parm type is specified by a function prototype.  */
2172           tree parmval;
2173
2174           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2175             {
2176               error ("type of formal parameter %d is incomplete", parmnum + 1);
2177               parmval = val;
2178             }
2179           else
2180             {
2181               /* Optionally warn about conversions that
2182                  differ from the default conversions.  */
2183               if (warn_conversion || warn_traditional)
2184                 {
2185                   unsigned int formal_prec = TYPE_PRECISION (type);
2186
2187                   if (INTEGRAL_TYPE_P (type)
2188                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2189                     warning (0, "passing argument %d of %qE as integer "
2190                              "rather than floating due to prototype",
2191                              argnum, rname);
2192                   if (INTEGRAL_TYPE_P (type)
2193                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2194                     warning (0, "passing argument %d of %qE as integer "
2195                              "rather than complex due to prototype",
2196                              argnum, rname);
2197                   else if (TREE_CODE (type) == COMPLEX_TYPE
2198                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2199                     warning (0, "passing argument %d of %qE as complex "
2200                              "rather than floating due to prototype",
2201                              argnum, rname);
2202                   else if (TREE_CODE (type) == REAL_TYPE
2203                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2204                     warning (0, "passing argument %d of %qE as floating "
2205                              "rather than integer due to prototype",
2206                              argnum, rname);
2207                   else if (TREE_CODE (type) == COMPLEX_TYPE
2208                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2209                     warning (0, "passing argument %d of %qE as complex "
2210                              "rather than integer due to prototype",
2211                              argnum, rname);
2212                   else if (TREE_CODE (type) == REAL_TYPE
2213                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2214                     warning (0, "passing argument %d of %qE as floating "
2215                              "rather than complex due to prototype",
2216                              argnum, rname);
2217                   /* ??? At some point, messages should be written about
2218                      conversions between complex types, but that's too messy
2219                      to do now.  */
2220                   else if (TREE_CODE (type) == REAL_TYPE
2221                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2222                     {
2223                       /* Warn if any argument is passed as `float',
2224                          since without a prototype it would be `double'.  */
2225                       if (formal_prec == TYPE_PRECISION (float_type_node))
2226                         warning (0, "passing argument %d of %qE as %<float%> "
2227                                  "rather than %<double%> due to prototype",
2228                                  argnum, rname);
2229                     }
2230                   /* Detect integer changing in width or signedness.
2231                      These warnings are only activated with
2232                      -Wconversion, not with -Wtraditional.  */
2233                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2234                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2235                     {
2236                       tree would_have_been = default_conversion (val);
2237                       tree type1 = TREE_TYPE (would_have_been);
2238
2239                       if (TREE_CODE (type) == ENUMERAL_TYPE
2240                           && (TYPE_MAIN_VARIANT (type)
2241                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2242                         /* No warning if function asks for enum
2243                            and the actual arg is that enum type.  */
2244                         ;
2245                       else if (formal_prec != TYPE_PRECISION (type1))
2246                         warning (0, "passing argument %d of %qE with different "
2247                                  "width due to prototype", argnum, rname);
2248                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2249                         ;
2250                       /* Don't complain if the formal parameter type
2251                          is an enum, because we can't tell now whether
2252                          the value was an enum--even the same enum.  */
2253                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2254                         ;
2255                       else if (TREE_CODE (val) == INTEGER_CST
2256                                && int_fits_type_p (val, type))
2257                         /* Change in signedness doesn't matter
2258                            if a constant value is unaffected.  */
2259                         ;
2260                       /* If the value is extended from a narrower
2261                          unsigned type, it doesn't matter whether we
2262                          pass it as signed or unsigned; the value
2263                          certainly is the same either way.  */
2264                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2265                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2266                         ;
2267                       else if (TYPE_UNSIGNED (type))
2268                         warning (0, "passing argument %d of %qE as unsigned "
2269                                  "due to prototype", argnum, rname);
2270                       else
2271                         warning (0, "passing argument %d of %qE as signed "
2272                                  "due to prototype", argnum, rname);
2273                     }
2274                 }
2275
2276               parmval = convert_for_assignment (type, val, ic_argpass,
2277                                                 fundecl, function,
2278                                                 parmnum + 1);
2279
2280               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2281                   && INTEGRAL_TYPE_P (type)
2282                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2283                 parmval = default_conversion (parmval);
2284             }
2285           result = tree_cons (NULL_TREE, parmval, result);
2286         }
2287       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2288                && (TYPE_PRECISION (TREE_TYPE (val))
2289                    < TYPE_PRECISION (double_type_node)))
2290         /* Convert `float' to `double'.  */
2291         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2292       else if ((invalid_func_diag =
2293                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2294         {
2295           error (invalid_func_diag);
2296           return error_mark_node;
2297         }
2298       else
2299         /* Convert `short' and `char' to full-size `int'.  */
2300         result = tree_cons (NULL_TREE, default_conversion (val), result);
2301
2302       if (typetail)
2303         typetail = TREE_CHAIN (typetail);
2304     }
2305
2306   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2307     {
2308       error ("too few arguments to function %qE", function);
2309       return error_mark_node;
2310     }
2311
2312   return nreverse (result);
2313 }
2314 \f
2315 /* This is the entry point used by the parser to build unary operators
2316    in the input.  CODE, a tree_code, specifies the unary operator, and
2317    ARG is the operand.  For unary plus, the C parser currently uses
2318    CONVERT_EXPR for code.  */
2319
2320 struct c_expr
2321 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2322 {
2323   struct c_expr result;
2324
2325   result.original_code = ERROR_MARK;
2326   result.value = build_unary_op (code, arg.value, 0);
2327   overflow_warning (result.value);
2328   return result;
2329 }
2330
2331 /* This is the entry point used by the parser to build binary operators
2332    in the input.  CODE, a tree_code, specifies the binary operator, and
2333    ARG1 and ARG2 are the operands.  In addition to constructing the
2334    expression, we check for operands that were written with other binary
2335    operators in a way that is likely to confuse the user.  */
2336
2337 struct c_expr
2338 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2339                         struct c_expr arg2)
2340 {
2341   struct c_expr result;
2342
2343   enum tree_code code1 = arg1.original_code;
2344   enum tree_code code2 = arg2.original_code;
2345
2346   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2347   result.original_code = code;
2348
2349   if (TREE_CODE (result.value) == ERROR_MARK)
2350     return result;
2351
2352   /* Check for cases such as x+y<<z which users are likely
2353      to misinterpret.  */
2354   if (warn_parentheses)
2355     {
2356       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2357         {
2358           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2359               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2360             warning (0, "suggest parentheses around + or - inside shift");
2361         }
2362
2363       if (code == TRUTH_ORIF_EXPR)
2364         {
2365           if (code1 == TRUTH_ANDIF_EXPR
2366               || code2 == TRUTH_ANDIF_EXPR)
2367             warning (0, "suggest parentheses around && within ||");
2368         }
2369
2370       if (code == BIT_IOR_EXPR)
2371         {
2372           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2373               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2374               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2375               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2376             warning (0, "suggest parentheses around arithmetic in operand of |");
2377           /* Check cases like x|y==z */
2378           if (TREE_CODE_CLASS (code1) == tcc_comparison
2379               || TREE_CODE_CLASS (code2) == tcc_comparison)
2380             warning (0, "suggest parentheses around comparison in operand of |");
2381         }
2382
2383       if (code == BIT_XOR_EXPR)
2384         {
2385           if (code1 == BIT_AND_EXPR
2386               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2387               || code2 == BIT_AND_EXPR
2388               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2389             warning (0, "suggest parentheses around arithmetic in operand of ^");
2390           /* Check cases like x^y==z */
2391           if (TREE_CODE_CLASS (code1) == tcc_comparison
2392               || TREE_CODE_CLASS (code2) == tcc_comparison)
2393             warning (0, "suggest parentheses around comparison in operand of ^");
2394         }
2395
2396       if (code == BIT_AND_EXPR)
2397         {
2398           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2399               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2400             warning (0, "suggest parentheses around + or - in operand of &");
2401           /* Check cases like x&y==z */
2402           if (TREE_CODE_CLASS (code1) == tcc_comparison
2403               || TREE_CODE_CLASS (code2) == tcc_comparison)
2404             warning (0, "suggest parentheses around comparison in operand of &");
2405         }
2406       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2407       if (TREE_CODE_CLASS (code) == tcc_comparison
2408           && (TREE_CODE_CLASS (code1) == tcc_comparison
2409               || TREE_CODE_CLASS (code2) == tcc_comparison))
2410         warning (0, "comparisons like X<=Y<=Z do not have their mathematical meaning");
2411
2412     }
2413
2414   unsigned_conversion_warning (result.value, arg1.value);
2415   unsigned_conversion_warning (result.value, arg2.value);
2416   overflow_warning (result.value);
2417
2418   return result;
2419 }
2420 \f
2421 /* Return a tree for the difference of pointers OP0 and OP1.
2422    The resulting tree has type int.  */
2423
2424 static tree
2425 pointer_diff (tree op0, tree op1)
2426 {
2427   tree restype = ptrdiff_type_node;
2428
2429   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2430   tree con0, con1, lit0, lit1;
2431   tree orig_op1 = op1;
2432
2433   if (pedantic || warn_pointer_arith)
2434     {
2435       if (TREE_CODE (target_type) == VOID_TYPE)
2436         pedwarn ("pointer of type %<void *%> used in subtraction");
2437       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2438         pedwarn ("pointer to a function used in subtraction");
2439     }
2440
2441   /* If the conversion to ptrdiff_type does anything like widening or
2442      converting a partial to an integral mode, we get a convert_expression
2443      that is in the way to do any simplifications.
2444      (fold-const.c doesn't know that the extra bits won't be needed.
2445      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2446      different mode in place.)
2447      So first try to find a common term here 'by hand'; we want to cover
2448      at least the cases that occur in legal static initializers.  */
2449   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2450   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2451
2452   if (TREE_CODE (con0) == PLUS_EXPR)
2453     {
2454       lit0 = TREE_OPERAND (con0, 1);
2455       con0 = TREE_OPERAND (con0, 0);
2456     }
2457   else
2458     lit0 = integer_zero_node;
2459
2460   if (TREE_CODE (con1) == PLUS_EXPR)
2461     {
2462       lit1 = TREE_OPERAND (con1, 1);
2463       con1 = TREE_OPERAND (con1, 0);
2464     }
2465   else
2466     lit1 = integer_zero_node;
2467
2468   if (operand_equal_p (con0, con1, 0))
2469     {
2470       op0 = lit0;
2471       op1 = lit1;
2472     }
2473
2474
2475   /* First do the subtraction as integers;
2476      then drop through to build the divide operator.
2477      Do not do default conversions on the minus operator
2478      in case restype is a short type.  */
2479
2480   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2481                          convert (restype, op1), 0);
2482   /* This generates an error if op1 is pointer to incomplete type.  */
2483   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2484     error ("arithmetic on pointer to an incomplete type");
2485
2486   /* This generates an error if op0 is pointer to incomplete type.  */
2487   op1 = c_size_in_bytes (target_type);
2488
2489   /* Divide by the size, in easiest possible way.  */
2490   return fold (build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1)));
2491 }
2492 \f
2493 /* Construct and perhaps optimize a tree representation
2494    for a unary operation.  CODE, a tree_code, specifies the operation
2495    and XARG is the operand.
2496    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2497    the default promotions (such as from short to int).
2498    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2499    allows non-lvalues; this is only used to handle conversion of non-lvalue
2500    arrays to pointers in C99.  */
2501
2502 tree
2503 build_unary_op (enum tree_code code, tree xarg, int flag)
2504 {
2505   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2506   tree arg = xarg;
2507   tree argtype = 0;
2508   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2509   tree val;
2510   int noconvert = flag;
2511
2512   if (typecode == ERROR_MARK)
2513     return error_mark_node;
2514   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2515     typecode = INTEGER_TYPE;
2516
2517   switch (code)
2518     {
2519     case CONVERT_EXPR:
2520       /* This is used for unary plus, because a CONVERT_EXPR
2521          is enough to prevent anybody from looking inside for
2522          associativity, but won't generate any code.  */
2523       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2524             || typecode == COMPLEX_TYPE
2525             || typecode == VECTOR_TYPE))
2526         {
2527           error ("wrong type argument to unary plus");
2528           return error_mark_node;
2529         }
2530       else if (!noconvert)
2531         arg = default_conversion (arg);
2532       arg = non_lvalue (arg);
2533       break;
2534
2535     case NEGATE_EXPR:
2536       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2537             || typecode == COMPLEX_TYPE
2538             || typecode == VECTOR_TYPE))
2539         {
2540           error ("wrong type argument to unary minus");
2541           return error_mark_node;
2542         }
2543       else if (!noconvert)
2544         arg = default_conversion (arg);
2545       break;
2546
2547     case BIT_NOT_EXPR:
2548       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2549         {
2550           if (!noconvert)
2551             arg = default_conversion (arg);
2552         }
2553       else if (typecode == COMPLEX_TYPE)
2554         {
2555           code = CONJ_EXPR;
2556           if (pedantic)
2557             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2558           if (!noconvert)
2559             arg = default_conversion (arg);
2560         }
2561       else
2562         {
2563           error ("wrong type argument to bit-complement");
2564           return error_mark_node;
2565         }
2566       break;
2567
2568     case ABS_EXPR:
2569       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2570         {
2571           error ("wrong type argument to abs");
2572           return error_mark_node;
2573         }
2574       else if (!noconvert)
2575         arg = default_conversion (arg);
2576       break;
2577
2578     case CONJ_EXPR:
2579       /* Conjugating a real value is a no-op, but allow it anyway.  */
2580       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2581             || typecode == COMPLEX_TYPE))
2582         {
2583           error ("wrong type argument to conjugation");
2584           return error_mark_node;
2585         }
2586       else if (!noconvert)
2587         arg = default_conversion (arg);
2588       break;
2589
2590     case TRUTH_NOT_EXPR:
2591       /* ??? Why do most validation here but that for non-lvalue arrays
2592          in c_objc_common_truthvalue_conversion?  */
2593       if (typecode != INTEGER_TYPE
2594           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2595           && typecode != COMPLEX_TYPE
2596           /* These will convert to a pointer.  */
2597           && typecode != ARRAY_TYPE && typecode != FUNCTION_TYPE)
2598         {
2599           error ("wrong type argument to unary exclamation mark");
2600           return error_mark_node;
2601         }
2602       arg = c_objc_common_truthvalue_conversion (arg);
2603       return invert_truthvalue (arg);
2604
2605     case NOP_EXPR:
2606       break;
2607
2608     case REALPART_EXPR:
2609       if (TREE_CODE (arg) == COMPLEX_CST)
2610         return TREE_REALPART (arg);
2611       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2612         return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2613       else
2614         return arg;
2615
2616     case IMAGPART_EXPR:
2617       if (TREE_CODE (arg) == COMPLEX_CST)
2618         return TREE_IMAGPART (arg);
2619       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2620         return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2621       else
2622         return convert (TREE_TYPE (arg), integer_zero_node);
2623
2624     case PREINCREMENT_EXPR:
2625     case POSTINCREMENT_EXPR:
2626     case PREDECREMENT_EXPR:
2627     case POSTDECREMENT_EXPR:
2628
2629       /* Increment or decrement the real part of the value,
2630          and don't change the imaginary part.  */
2631       if (typecode == COMPLEX_TYPE)
2632         {
2633           tree real, imag;
2634
2635           if (pedantic)
2636             pedwarn ("ISO C does not support %<++%> and %<--%>"
2637                      " on complex types");
2638
2639           arg = stabilize_reference (arg);
2640           real = build_unary_op (REALPART_EXPR, arg, 1);
2641           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2642           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2643                          build_unary_op (code, real, 1), imag);
2644         }
2645
2646       /* Report invalid types.  */
2647
2648       if (typecode != POINTER_TYPE
2649           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2650         {
2651           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2652             error ("wrong type argument to increment");
2653           else
2654             error ("wrong type argument to decrement");
2655
2656           return error_mark_node;
2657         }
2658
2659       {
2660         tree inc;
2661         tree result_type = TREE_TYPE (arg);
2662
2663         arg = get_unwidened (arg, 0);
2664         argtype = TREE_TYPE (arg);
2665
2666         /* Compute the increment.  */
2667
2668         if (typecode == POINTER_TYPE)
2669           {
2670             /* If pointer target is an undefined struct,
2671                we just cannot know how to do the arithmetic.  */
2672             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2673               {
2674                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2675                   error ("increment of pointer to unknown structure");
2676                 else
2677                   error ("decrement of pointer to unknown structure");
2678               }
2679             else if ((pedantic || warn_pointer_arith)
2680                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2681                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2682               {
2683                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2684                   pedwarn ("wrong type argument to increment");
2685                 else
2686                   pedwarn ("wrong type argument to decrement");
2687               }
2688
2689             inc = c_size_in_bytes (TREE_TYPE (result_type));
2690           }
2691         else
2692           inc = integer_one_node;
2693
2694         inc = convert (argtype, inc);
2695
2696         /* Complain about anything else that is not a true lvalue.  */
2697         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2698                                     || code == POSTINCREMENT_EXPR)
2699                                    ? lv_increment
2700                                    : lv_decrement)))
2701           return error_mark_node;
2702
2703         /* Report a read-only lvalue.  */
2704         if (TREE_READONLY (arg))
2705           readonly_error (arg,
2706                           ((code == PREINCREMENT_EXPR
2707                             || code == POSTINCREMENT_EXPR)
2708                            ? lv_increment : lv_decrement));
2709
2710         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2711           val = boolean_increment (code, arg);
2712         else
2713           val = build2 (code, TREE_TYPE (arg), arg, inc);
2714         TREE_SIDE_EFFECTS (val) = 1;
2715         val = convert (result_type, val);
2716         if (TREE_CODE (val) != code)
2717           TREE_NO_WARNING (val) = 1;
2718         return val;
2719       }
2720
2721     case ADDR_EXPR:
2722       /* Note that this operation never does default_conversion.  */
2723
2724       /* Let &* cancel out to simplify resulting code.  */
2725       if (TREE_CODE (arg) == INDIRECT_REF)
2726         {
2727           /* Don't let this be an lvalue.  */
2728           if (lvalue_p (TREE_OPERAND (arg, 0)))
2729             return non_lvalue (TREE_OPERAND (arg, 0));
2730           return TREE_OPERAND (arg, 0);
2731         }
2732
2733       /* For &x[y], return x+y */
2734       if (TREE_CODE (arg) == ARRAY_REF)
2735         {
2736           if (!c_mark_addressable (TREE_OPERAND (arg, 0)))
2737             return error_mark_node;
2738           return build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
2739                                   TREE_OPERAND (arg, 1), 1);
2740         }
2741
2742       /* Anything not already handled and not a true memory reference
2743          or a non-lvalue array is an error.  */
2744       else if (typecode != FUNCTION_TYPE && !flag
2745                && !lvalue_or_else (arg, lv_addressof))
2746         return error_mark_node;
2747
2748       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2749       argtype = TREE_TYPE (arg);
2750
2751       /* If the lvalue is const or volatile, merge that into the type
2752          to which the address will point.  Note that you can't get a
2753          restricted pointer by taking the address of something, so we
2754          only have to deal with `const' and `volatile' here.  */
2755       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2756           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2757           argtype = c_build_type_variant (argtype,
2758                                           TREE_READONLY (arg),
2759                                           TREE_THIS_VOLATILE (arg));
2760
2761       if (!c_mark_addressable (arg))
2762         return error_mark_node;
2763
2764       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2765                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2766
2767       argtype = build_pointer_type (argtype);
2768
2769       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2770          when we have proper support for integer constant expressions.  */
2771       val = get_base_address (arg);
2772       if (val && TREE_CODE (val) == INDIRECT_REF
2773           && integer_zerop (TREE_OPERAND (val, 0)))
2774         return fold_convert (argtype, fold_offsetof (arg));
2775
2776       val = build1 (ADDR_EXPR, argtype, arg);
2777
2778       if (TREE_CODE (arg) == COMPOUND_LITERAL_EXPR)
2779         TREE_INVARIANT (val) = TREE_CONSTANT (val) = 1;
2780
2781       return val;
2782
2783     default:
2784       break;
2785     }
2786
2787   if (argtype == 0)
2788     argtype = TREE_TYPE (arg);
2789   val = build1 (code, argtype, arg);
2790   return require_constant_value ? fold_initializer (val) : fold (val);
2791 }
2792
2793 /* Return nonzero if REF is an lvalue valid for this language.
2794    Lvalues can be assigned, unless their type has TYPE_READONLY.
2795    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2796
2797 static int
2798 lvalue_p (tree ref)
2799 {
2800   enum tree_code code = TREE_CODE (ref);
2801
2802   switch (code)
2803     {
2804     case REALPART_EXPR:
2805     case IMAGPART_EXPR:
2806     case COMPONENT_REF:
2807       return lvalue_p (TREE_OPERAND (ref, 0));
2808
2809     case COMPOUND_LITERAL_EXPR:
2810     case STRING_CST:
2811       return 1;
2812
2813     case INDIRECT_REF:
2814     case ARRAY_REF:
2815     case VAR_DECL:
2816     case PARM_DECL:
2817     case RESULT_DECL:
2818     case ERROR_MARK:
2819       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2820               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2821
2822     case BIND_EXPR:
2823       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2824
2825     default:
2826       return 0;
2827     }
2828 }
2829 \f
2830 /* Give an error for storing in something that is 'const'.  */
2831
2832 static void
2833 readonly_error (tree arg, enum lvalue_use use)
2834 {
2835   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement);
2836   /* Using this macro rather than (for example) arrays of messages
2837      ensures that all the format strings are checked at compile
2838      time.  */
2839 #define READONLY_MSG(A, I, D) (use == lv_assign                         \
2840                                ? (A)                                    \
2841                                : (use == lv_increment ? (I) : (D)))
2842   if (TREE_CODE (arg) == COMPONENT_REF)
2843     {
2844       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2845         readonly_error (TREE_OPERAND (arg, 0), use);
2846       else
2847         error (READONLY_MSG (N_("assignment of read-only member %qD"),
2848                              N_("increment of read-only member %qD"),
2849                              N_("decrement of read-only member %qD")),
2850                TREE_OPERAND (arg, 1));
2851     }
2852   else if (TREE_CODE (arg) == VAR_DECL)
2853     error (READONLY_MSG (N_("assignment of read-only variable %qD"),
2854                          N_("increment of read-only variable %qD"),
2855                          N_("decrement of read-only variable %qD")),
2856            arg);
2857   else
2858     error (READONLY_MSG (N_("assignment of read-only location"),
2859                          N_("increment of read-only location"),
2860                          N_("decrement of read-only location")));
2861 }
2862
2863
2864 /* Return nonzero if REF is an lvalue valid for this language;
2865    otherwise, print an error message and return zero.  USE says
2866    how the lvalue is being used and so selects the error message.  */
2867
2868 static int
2869 lvalue_or_else (tree ref, enum lvalue_use use)
2870 {
2871   int win = lvalue_p (ref);
2872
2873   if (!win)
2874     lvalue_error (use);
2875
2876   return win;
2877 }
2878 \f
2879 /* Mark EXP saying that we need to be able to take the
2880    address of it; it should not be allocated in a register.
2881    Returns true if successful.  */
2882
2883 bool
2884 c_mark_addressable (tree exp)
2885 {
2886   tree x = exp;
2887
2888   while (1)
2889     switch (TREE_CODE (x))
2890       {
2891       case COMPONENT_REF:
2892         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2893           {
2894             error
2895               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
2896             return false;
2897           }
2898
2899         /* ... fall through ...  */
2900
2901       case ADDR_EXPR:
2902       case ARRAY_REF:
2903       case REALPART_EXPR:
2904       case IMAGPART_EXPR:
2905         x = TREE_OPERAND (x, 0);
2906         break;
2907
2908       case COMPOUND_LITERAL_EXPR:
2909       case CONSTRUCTOR:
2910         TREE_ADDRESSABLE (x) = 1;
2911         return true;
2912
2913       case VAR_DECL:
2914       case CONST_DECL:
2915       case PARM_DECL:
2916       case RESULT_DECL:
2917         if (C_DECL_REGISTER (x)
2918             && DECL_NONLOCAL (x))
2919           {
2920             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2921               {
2922                 error
2923                   ("global register variable %qD used in nested function", x);
2924                 return false;
2925               }
2926             pedwarn ("register variable %qD used in nested function", x);
2927           }
2928         else if (C_DECL_REGISTER (x))
2929           {
2930             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2931               error ("address of global register variable %qD requested", x);
2932             else
2933               error ("address of register variable %qD requested", x);
2934             return false;
2935           }
2936
2937         /* drops in */
2938       case FUNCTION_DECL:
2939         TREE_ADDRESSABLE (x) = 1;
2940         /* drops out */
2941       default:
2942         return true;
2943     }
2944 }
2945 \f
2946 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2947
2948 tree
2949 build_conditional_expr (tree ifexp, tree op1, tree op2)
2950 {
2951   tree type1;
2952   tree type2;
2953   enum tree_code code1;
2954   enum tree_code code2;
2955   tree result_type = NULL;
2956   tree orig_op1 = op1, orig_op2 = op2;
2957
2958   /* Promote both alternatives.  */
2959
2960   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
2961     op1 = default_conversion (op1);
2962   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
2963     op2 = default_conversion (op2);
2964
2965   if (TREE_CODE (ifexp) == ERROR_MARK
2966       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
2967       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
2968     return error_mark_node;
2969
2970   type1 = TREE_TYPE (op1);
2971   code1 = TREE_CODE (type1);
2972   type2 = TREE_TYPE (op2);
2973   code2 = TREE_CODE (type2);
2974
2975   /* C90 does not permit non-lvalue arrays in conditional expressions.
2976      In C99 they will be pointers by now.  */
2977   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
2978     {
2979       error ("non-lvalue array in conditional expression");
2980       return error_mark_node;
2981     }
2982
2983   /* Quickly detect the usual case where op1 and op2 have the same type
2984      after promotion.  */
2985   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
2986     {
2987       if (type1 == type2)
2988         result_type = type1;
2989       else
2990         result_type = TYPE_MAIN_VARIANT (type1);
2991     }
2992   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
2993             || code1 == COMPLEX_TYPE)
2994            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
2995                || code2 == COMPLEX_TYPE))
2996     {
2997       result_type = c_common_type (type1, type2);
2998
2999       /* If -Wsign-compare, warn here if type1 and type2 have
3000          different signedness.  We'll promote the signed to unsigned
3001          and later code won't know it used to be different.
3002          Do this check on the original types, so that explicit casts
3003          will be considered, but default promotions won't.  */
3004       if (warn_sign_compare && !skip_evaluation)
3005         {
3006           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3007           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3008
3009           if (unsigned_op1 ^ unsigned_op2)
3010             {
3011               /* Do not warn if the result type is signed, since the
3012                  signed type will only be chosen if it can represent
3013                  all the values of the unsigned type.  */
3014               if (!TYPE_UNSIGNED (result_type))
3015                 /* OK */;
3016               /* Do not warn if the signed quantity is an unsuffixed
3017                  integer literal (or some static constant expression
3018                  involving such literals) and it is non-negative.  */
3019               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3020                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3021                 /* OK */;
3022               else
3023                 warning (0, "signed and unsigned type in conditional expression");
3024             }
3025         }
3026     }
3027   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3028     {
3029       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3030         pedwarn ("ISO C forbids conditional expr with only one void side");
3031       result_type = void_type_node;
3032     }
3033   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3034     {
3035       if (comp_target_types (type1, type2, 1))
3036         result_type = common_pointer_type (type1, type2);
3037       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3038                && TREE_CODE (orig_op1) != NOP_EXPR)
3039         result_type = qualify_type (type2, type1);
3040       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3041                && TREE_CODE (orig_op2) != NOP_EXPR)
3042         result_type = qualify_type (type1, type2);
3043       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3044         {
3045           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3046             pedwarn ("ISO C forbids conditional expr between "
3047                      "%<void *%> and function pointer");
3048           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3049                                                           TREE_TYPE (type2)));
3050         }
3051       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3052         {
3053           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3054             pedwarn ("ISO C forbids conditional expr between "
3055                      "%<void *%> and function pointer");
3056           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3057                                                           TREE_TYPE (type1)));
3058         }
3059       else
3060         {
3061           pedwarn ("pointer type mismatch in conditional expression");
3062           result_type = build_pointer_type (void_type_node);
3063         }
3064     }
3065   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3066     {
3067       if (!integer_zerop (op2))
3068         pedwarn ("pointer/integer type mismatch in conditional expression");
3069       else
3070         {
3071           op2 = null_pointer_node;
3072         }
3073       result_type = type1;
3074     }
3075   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3076     {
3077       if (!integer_zerop (op1))
3078         pedwarn ("pointer/integer type mismatch in conditional expression");
3079       else
3080         {
3081           op1 = null_pointer_node;
3082         }
3083       result_type = type2;
3084     }
3085
3086   if (!result_type)
3087     {
3088       if (flag_cond_mismatch)
3089         result_type = void_type_node;
3090       else
3091         {
3092           error ("type mismatch in conditional expression");
3093           return error_mark_node;
3094         }
3095     }
3096
3097   /* Merge const and volatile flags of the incoming types.  */
3098   result_type
3099     = build_type_variant (result_type,
3100                           TREE_READONLY (op1) || TREE_READONLY (op2),
3101                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3102
3103   if (result_type != TREE_TYPE (op1))
3104     op1 = convert_and_check (result_type, op1);
3105   if (result_type != TREE_TYPE (op2))
3106     op2 = convert_and_check (result_type, op2);
3107
3108   if (TREE_CODE (ifexp) == INTEGER_CST)
3109     return non_lvalue (integer_zerop (ifexp) ? op2 : op1);
3110
3111   return fold (build3 (COND_EXPR, result_type, ifexp, op1, op2));
3112 }
3113 \f
3114 /* Return a compound expression that performs two expressions and
3115    returns the value of the second of them.  */
3116
3117 tree
3118 build_compound_expr (tree expr1, tree expr2)
3119 {
3120   /* Convert arrays and functions to pointers.  */
3121   expr2 = default_function_array_conversion (expr2);
3122
3123   if (!TREE_SIDE_EFFECTS (expr1))
3124     {
3125       /* The left-hand operand of a comma expression is like an expression
3126          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3127          any side-effects, unless it was explicitly cast to (void).  */
3128       if (warn_unused_value)
3129         {
3130           if (VOID_TYPE_P (TREE_TYPE (expr1))
3131               && TREE_CODE (expr1) == CONVERT_EXPR)
3132             ; /* (void) a, b */
3133           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3134                    && TREE_CODE (expr1) == COMPOUND_EXPR
3135                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3136             ; /* (void) a, (void) b, c */
3137           else
3138             warning (0, "left-hand operand of comma expression has no effect");
3139         }
3140     }
3141
3142   /* With -Wunused, we should also warn if the left-hand operand does have
3143      side-effects, but computes a value which is not used.  For example, in
3144      `foo() + bar(), baz()' the result of the `+' operator is not used,
3145      so we should issue a warning.  */
3146   else if (warn_unused_value)
3147     warn_if_unused_value (expr1, input_location);
3148
3149   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3150 }
3151
3152 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3153
3154 tree
3155 build_c_cast (tree type, tree expr)
3156 {
3157   tree value = expr;
3158
3159   if (type == error_mark_node || expr == error_mark_node)
3160     return error_mark_node;
3161
3162   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3163      only in <protocol> qualifications.  But when constructing cast expressions,
3164      the protocols do matter and must be kept around.  */
3165   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3166     return build1 (NOP_EXPR, type, expr);
3167
3168   type = TYPE_MAIN_VARIANT (type);
3169
3170   if (TREE_CODE (type) == ARRAY_TYPE)
3171     {
3172       error ("cast specifies array type");
3173       return error_mark_node;
3174     }
3175
3176   if (TREE_CODE (type) == FUNCTION_TYPE)
3177     {
3178       error ("cast specifies function type");
3179       return error_mark_node;
3180     }
3181
3182   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3183     {
3184       if (pedantic)
3185         {
3186           if (TREE_CODE (type) == RECORD_TYPE
3187               || TREE_CODE (type) == UNION_TYPE)
3188             pedwarn ("ISO C forbids casting nonscalar to the same type");
3189         }
3190     }
3191   else if (TREE_CODE (type) == UNION_TYPE)
3192     {
3193       tree field;
3194       value = default_function_array_conversion (value);
3195
3196       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3197         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3198                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3199           break;
3200
3201       if (field)
3202         {
3203           tree t;
3204
3205           if (pedantic)
3206             pedwarn ("ISO C forbids casts to union type");
3207           t = digest_init (type,
3208                            build_constructor (type,
3209                                               build_tree_list (field, value)),
3210                            true, 0);
3211           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3212           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3213           return t;
3214         }
3215       error ("cast to union type from type not present in union");
3216       return error_mark_node;
3217     }
3218   else
3219     {
3220       tree otype, ovalue;
3221
3222       /* If casting to void, avoid the error that would come
3223          from default_conversion in the case of a non-lvalue array.  */
3224       if (type == void_type_node)
3225         return build1 (CONVERT_EXPR, type, value);
3226
3227       /* Convert functions and arrays to pointers,
3228          but don't convert any other types.  */
3229       value = default_function_array_conversion (value);
3230       otype = TREE_TYPE (value);
3231
3232       /* Optionally warn about potentially worrisome casts.  */
3233
3234       if (warn_cast_qual
3235           && TREE_CODE (type) == POINTER_TYPE
3236           && TREE_CODE (otype) == POINTER_TYPE)
3237         {
3238           tree in_type = type;
3239           tree in_otype = otype;
3240           int added = 0;
3241           int discarded = 0;
3242
3243           /* Check that the qualifiers on IN_TYPE are a superset of
3244              the qualifiers of IN_OTYPE.  The outermost level of
3245              POINTER_TYPE nodes is uninteresting and we stop as soon
3246              as we hit a non-POINTER_TYPE node on either type.  */
3247           do
3248             {
3249               in_otype = TREE_TYPE (in_otype);
3250               in_type = TREE_TYPE (in_type);
3251
3252               /* GNU C allows cv-qualified function types.  'const'
3253                  means the function is very pure, 'volatile' means it
3254                  can't return.  We need to warn when such qualifiers
3255                  are added, not when they're taken away.  */
3256               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3257                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3258                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3259               else
3260                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3261             }
3262           while (TREE_CODE (in_type) == POINTER_TYPE
3263                  && TREE_CODE (in_otype) == POINTER_TYPE);
3264
3265           if (added)
3266             warning (0, "cast adds new qualifiers to function type");
3267
3268           if (discarded)
3269             /* There are qualifiers present in IN_OTYPE that are not
3270                present in IN_TYPE.  */
3271             warning (0, "cast discards qualifiers from pointer target type");
3272         }
3273
3274       /* Warn about possible alignment problems.  */
3275       if (STRICT_ALIGNMENT && warn_cast_align
3276           && TREE_CODE (type) == POINTER_TYPE
3277           && TREE_CODE (otype) == POINTER_TYPE
3278           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3279           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3280           /* Don't warn about opaque types, where the actual alignment
3281              restriction is unknown.  */
3282           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3283                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3284                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3285           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3286         warning (0, "cast increases required alignment of target type");
3287
3288       if (warn_pointer_to_int_cast
3289           && TREE_CODE (type) == INTEGER_TYPE
3290           && TREE_CODE (otype) == POINTER_TYPE
3291           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3292           && !TREE_CONSTANT (value))
3293         warning (0, "cast from pointer to integer of different size");
3294
3295       if (warn_bad_function_cast
3296           && TREE_CODE (value) == CALL_EXPR
3297           && TREE_CODE (type) != TREE_CODE (otype))
3298         warning (0, "cast from function call of type %qT to non-matching "
3299                  "type %qT", otype, type);
3300
3301       if (warn_int_to_pointer_cast
3302           && TREE_CODE (type) == POINTER_TYPE
3303           && TREE_CODE (otype) == INTEGER_TYPE
3304           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3305           /* Don't warn about converting any constant.  */
3306           && !TREE_CONSTANT (value))
3307         warning (0, "cast to pointer from integer of different size");
3308
3309       if (TREE_CODE (type) == POINTER_TYPE
3310           && TREE_CODE (otype) == POINTER_TYPE
3311           && TREE_CODE (expr) == ADDR_EXPR
3312           && DECL_P (TREE_OPERAND (expr, 0))
3313           && flag_strict_aliasing && warn_strict_aliasing
3314           && !VOID_TYPE_P (TREE_TYPE (type)))
3315         {
3316           /* Casting the address of a decl to non void pointer. Warn
3317              if the cast breaks type based aliasing.  */
3318           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3319             warning (0, "type-punning to incomplete type might break strict-aliasing rules");
3320           else
3321             {
3322               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3323               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3324
3325               if (!alias_sets_conflict_p (set1, set2))
3326                 warning (0, "dereferencing type-punned pointer will break strict-aliasing rules");
3327               else if (warn_strict_aliasing > 1
3328                        && !alias_sets_might_conflict_p (set1, set2))
3329                 warning (0, "dereferencing type-punned pointer might break strict-aliasing rules");
3330             }
3331         }
3332
3333       /* If pedantic, warn for conversions between function and object
3334          pointer types, except for converting a null pointer constant
3335          to function pointer type.  */
3336       if (pedantic
3337           && TREE_CODE (type) == POINTER_TYPE
3338           && TREE_CODE (otype) == POINTER_TYPE
3339           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3340           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3341         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3342
3343       if (pedantic
3344           && TREE_CODE (type) == POINTER_TYPE
3345           && TREE_CODE (otype) == POINTER_TYPE
3346           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3347           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3348           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3349                && TREE_CODE (expr) != NOP_EXPR))
3350         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3351
3352       ovalue = value;
3353       value = convert (type, value);
3354
3355       /* Ignore any integer overflow caused by the cast.  */
3356       if (TREE_CODE (value) == INTEGER_CST)
3357         {
3358           if (EXPR_P (ovalue))
3359             /* If OVALUE had overflow set, then so will VALUE, so it
3360                is safe to overwrite.  */
3361             TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3362           else
3363             TREE_OVERFLOW (value) = 0;
3364
3365           if (CONSTANT_CLASS_P (ovalue))
3366             /* Similarly, constant_overflow cannot have become
3367                cleared.  */
3368             TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3369         }
3370     }
3371
3372   /* Don't let a cast be an lvalue.  */
3373   if (value == expr)
3374     value = non_lvalue (value);
3375
3376   return value;
3377 }
3378
3379 /* Interpret a cast of expression EXPR to type TYPE.  */
3380 tree
3381 c_cast_expr (struct c_type_name *type_name, tree expr)
3382 {
3383   tree type;
3384   int saved_wsp = warn_strict_prototypes;
3385
3386   /* This avoids warnings about unprototyped casts on
3387      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3388   if (TREE_CODE (expr) == INTEGER_CST)
3389     warn_strict_prototypes = 0;
3390   type = groktypename (type_name);
3391   warn_strict_prototypes = saved_wsp;
3392
3393   return build_c_cast (type, expr);
3394 }
3395
3396 \f
3397 /* Build an assignment expression of lvalue LHS from value RHS.
3398    MODIFYCODE is the code for a binary operator that we use
3399    to combine the old value of LHS with RHS to get the new value.
3400    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3401
3402 tree
3403 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3404 {
3405   tree result;
3406   tree newrhs;
3407   tree lhstype = TREE_TYPE (lhs);
3408   tree olhstype = lhstype;
3409
3410   /* Types that aren't fully specified cannot be used in assignments.  */
3411   lhs = require_complete_type (lhs);
3412
3413   /* Avoid duplicate error messages from operands that had errors.  */
3414   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3415     return error_mark_node;
3416
3417   STRIP_TYPE_NOPS (rhs);
3418
3419   newrhs = rhs;
3420
3421   /* If a binary op has been requested, combine the old LHS value with the RHS
3422      producing the value we should actually store into the LHS.  */
3423
3424   if (modifycode != NOP_EXPR)
3425     {
3426       lhs = stabilize_reference (lhs);
3427       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3428     }
3429
3430   if (!lvalue_or_else (lhs, lv_assign))
3431     return error_mark_node;
3432
3433   /* Give an error for storing in something that is 'const'.  */
3434
3435   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3436       || ((TREE_CODE (lhstype) == RECORD_TYPE
3437            || TREE_CODE (lhstype) == UNION_TYPE)
3438           && C_TYPE_FIELDS_READONLY (lhstype)))
3439     readonly_error (lhs, lv_assign);
3440
3441   /* If storing into a structure or union member,
3442      it has probably been given type `int'.
3443      Compute the type that would go with
3444      the actual amount of storage the member occupies.  */
3445
3446   if (TREE_CODE (lhs) == COMPONENT_REF
3447       && (TREE_CODE (lhstype) == INTEGER_TYPE
3448           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3449           || TREE_CODE (lhstype) == REAL_TYPE
3450           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3451     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3452
3453   /* If storing in a field that is in actuality a short or narrower than one,
3454      we must store in the field in its actual type.  */
3455
3456   if (lhstype != TREE_TYPE (lhs))
3457     {
3458       lhs = copy_node (lhs);
3459       TREE_TYPE (lhs) = lhstype;
3460     }
3461
3462   /* Convert new value to destination type.  */
3463
3464   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3465                                    NULL_TREE, NULL_TREE, 0);
3466   if (TREE_CODE (newrhs) == ERROR_MARK)
3467     return error_mark_node;
3468
3469   /* Scan operands.  */
3470
3471   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3472   TREE_SIDE_EFFECTS (result) = 1;
3473
3474   /* If we got the LHS in a different type for storing in,
3475      convert the result back to the nominal type of LHS
3476      so that the value we return always has the same type
3477      as the LHS argument.  */
3478
3479   if (olhstype == TREE_TYPE (result))
3480     return result;
3481   return convert_for_assignment (olhstype, result, ic_assign,
3482                                  NULL_TREE, NULL_TREE, 0);
3483 }
3484 \f
3485 /* Convert value RHS to type TYPE as preparation for an assignment
3486    to an lvalue of type TYPE.
3487    The real work of conversion is done by `convert'.
3488    The purpose of this function is to generate error messages
3489    for assignments that are not allowed in C.
3490    ERRTYPE says whether it is argument passing, assignment,
3491    initialization or return.
3492
3493    FUNCTION is a tree for the function being called.
3494    PARMNUM is the number of the argument, for printing in error messages.  */
3495
3496 static tree
3497 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3498                         tree fundecl, tree function, int parmnum)
3499 {
3500   enum tree_code codel = TREE_CODE (type);
3501   tree rhstype;
3502   enum tree_code coder;
3503   tree rname = NULL_TREE;
3504
3505   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3506     {
3507       tree selector;
3508       /* Change pointer to function to the function itself for
3509          diagnostics.  */
3510       if (TREE_CODE (function) == ADDR_EXPR
3511           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3512         function = TREE_OPERAND (function, 0);
3513
3514       /* Handle an ObjC selector specially for diagnostics.  */
3515       selector = objc_message_selector ();
3516       rname = function;
3517       if (selector && parmnum > 2)
3518         {
3519           rname = selector;
3520           parmnum -= 2;
3521         }
3522     }
3523
3524   /* This macro is used to emit diagnostics to ensure that all format
3525      strings are complete sentences, visible to gettext and checked at
3526      compile time.  */
3527 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3528   do {                                          \
3529     switch (errtype)                            \
3530       {                                         \
3531       case ic_argpass:                          \
3532         pedwarn (AR, parmnum, rname);           \
3533         break;                                  \
3534       case ic_argpass_nonproto:                 \
3535         warning (0, AR, parmnum, rname);                \
3536         break;                                  \
3537       case ic_assign:                           \
3538         pedwarn (AS);                           \
3539         break;                                  \
3540       case ic_init:                             \
3541         pedwarn (IN);                           \
3542         break;                                  \
3543       case ic_return:                           \
3544         pedwarn (RE);                           \
3545         break;                                  \
3546       default:                                  \
3547         gcc_unreachable ();                     \
3548       }                                         \
3549   } while (0)
3550
3551   STRIP_TYPE_NOPS (rhs);
3552
3553   if (TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
3554       || TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE)
3555     rhs = default_conversion (rhs);
3556   else if (optimize && TREE_CODE (rhs) == VAR_DECL)
3557     rhs = decl_constant_value_for_broken_optimization (rhs);
3558
3559   rhstype = TREE_TYPE (rhs);
3560   coder = TREE_CODE (rhstype);
3561
3562   if (coder == ERROR_MARK)
3563     return error_mark_node;
3564
3565   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3566     {
3567       overflow_warning (rhs);
3568       /* Check for Objective-C protocols.  This will automatically
3569          issue a warning if there are protocol violations.  No need to
3570          use the return value.  */
3571       if (c_dialect_objc ())
3572         objc_comptypes (type, rhstype, 0);
3573       return rhs;
3574     }
3575
3576   if (coder == VOID_TYPE)
3577     {
3578       /* Except for passing an argument to an unprototyped function,
3579          this is a constraint violation.  When passing an argument to
3580          an unprototyped function, it is compile-time undefined;
3581          making it a constraint in that case was rejected in
3582          DR#252.  */
3583       error ("void value not ignored as it ought to be");
3584       return error_mark_node;
3585     }
3586   /* A type converts to a reference to it.
3587      This code doesn't fully support references, it's just for the
3588      special case of va_start and va_copy.  */
3589   if (codel == REFERENCE_TYPE
3590       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3591     {
3592       if (!lvalue_p (rhs))
3593         {
3594           error ("cannot pass rvalue to reference parameter");
3595           return error_mark_node;
3596         }
3597       if (!c_mark_addressable (rhs))
3598         return error_mark_node;
3599       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3600
3601       /* We already know that these two types are compatible, but they
3602          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3603          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3604          likely to be va_list, a typedef to __builtin_va_list, which
3605          is different enough that it will cause problems later.  */
3606       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3607         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3608
3609       rhs = build1 (NOP_EXPR, type, rhs);
3610       return rhs;
3611     }
3612   /* Some types can interconvert without explicit casts.  */
3613   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3614            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3615     return convert (type, rhs);
3616   /* Arithmetic types all interconvert, and enum is treated like int.  */
3617   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3618             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3619             || codel == BOOLEAN_TYPE)
3620            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3621                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3622                || coder == BOOLEAN_TYPE))
3623     return convert_and_check (type, rhs);
3624
3625   /* Conversion to a transparent union from its member types.
3626      This applies only to function arguments.  */
3627   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3628            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3629     {
3630       tree memb_types;
3631       tree marginal_memb_type = 0;
3632
3633       for (memb_types = TYPE_FIELDS (type); memb_types;
3634            memb_types = TREE_CHAIN (memb_types))
3635         {
3636           tree memb_type = TREE_TYPE (memb_types);
3637
3638           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3639                          TYPE_MAIN_VARIANT (rhstype)))
3640             break;
3641
3642           if (TREE_CODE (memb_type) != POINTER_TYPE)
3643             continue;
3644
3645           if (coder == POINTER_TYPE)
3646             {
3647               tree ttl = TREE_TYPE (memb_type);
3648               tree ttr = TREE_TYPE (rhstype);
3649
3650               /* Any non-function converts to a [const][volatile] void *
3651                  and vice versa; otherwise, targets must be the same.
3652                  Meanwhile, the lhs target must have all the qualifiers of
3653                  the rhs.  */
3654               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3655                   || comp_target_types (memb_type, rhstype, 0))
3656                 {
3657                   /* If this type won't generate any warnings, use it.  */
3658                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3659                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3660                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3661                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3662                              == TYPE_QUALS (ttr))
3663                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3664                              == TYPE_QUALS (ttl))))
3665                     break;
3666
3667                   /* Keep looking for a better type, but remember this one.  */
3668                   if (!marginal_memb_type)
3669                     marginal_memb_type = memb_type;
3670                 }
3671             }
3672
3673           /* Can convert integer zero to any pointer type.  */
3674           if (integer_zerop (rhs)
3675               || (TREE_CODE (rhs) == NOP_EXPR
3676                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3677             {
3678               rhs = null_pointer_node;
3679               break;
3680             }
3681         }
3682
3683       if (memb_types || marginal_memb_type)
3684         {
3685           if (!memb_types)
3686             {
3687               /* We have only a marginally acceptable member type;
3688                  it needs a warning.  */
3689               tree ttl = TREE_TYPE (marginal_memb_type);
3690               tree ttr = TREE_TYPE (rhstype);
3691
3692               /* Const and volatile mean something different for function
3693                  types, so the usual warnings are not appropriate.  */
3694               if (TREE_CODE (ttr) == FUNCTION_TYPE
3695                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3696                 {
3697                   /* Because const and volatile on functions are
3698                      restrictions that say the function will not do
3699                      certain things, it is okay to use a const or volatile
3700                      function where an ordinary one is wanted, but not
3701                      vice-versa.  */
3702                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3703                     WARN_FOR_ASSIGNMENT (N_("passing argument %d of %qE "
3704                                             "makes qualified function "
3705                                             "pointer from unqualified"),
3706                                          N_("assignment makes qualified "
3707                                             "function pointer from "
3708                                             "unqualified"),
3709                                          N_("initialization makes qualified "
3710                                             "function pointer from "
3711                                             "unqualified"),
3712                                          N_("return makes qualified function "
3713                                             "pointer from unqualified"));
3714                 }
3715               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3716                 WARN_FOR_ASSIGNMENT (N_("passing argument %d of %qE discards "
3717                                         "qualifiers from pointer target type"),
3718                                      N_("assignment discards qualifiers "
3719                                         "from pointer target type"),
3720                                      N_("initialization discards qualifiers "
3721                                         "from pointer target type"),
3722                                      N_("return discards qualifiers from "
3723                                         "pointer target type"));
3724             }
3725
3726           if (pedantic && !DECL_IN_SYSTEM_HEADER (fundecl))
3727             pedwarn ("ISO C prohibits argument conversion to union type");
3728
3729           return build1 (NOP_EXPR, type, rhs);
3730         }
3731     }
3732
3733   /* Conversions among pointers */
3734   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3735            && (coder == codel))
3736     {
3737       tree ttl = TREE_TYPE (type);
3738       tree ttr = TREE_TYPE (rhstype);
3739       tree mvl = ttl;
3740       tree mvr = ttr;
3741       bool is_opaque_pointer;
3742       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3743
3744       if (TREE_CODE (mvl) != ARRAY_TYPE)
3745         mvl = TYPE_MAIN_VARIANT (mvl);
3746       if (TREE_CODE (mvr) != ARRAY_TYPE)
3747         mvr = TYPE_MAIN_VARIANT (mvr);
3748       /* Opaque pointers are treated like void pointers.  */
3749       is_opaque_pointer = (targetm.vector_opaque_p (type)
3750                            || targetm.vector_opaque_p (rhstype))
3751         && TREE_CODE (ttl) == VECTOR_TYPE
3752         && TREE_CODE (ttr) == VECTOR_TYPE;
3753
3754       /* Any non-function converts to a [const][volatile] void *
3755          and vice versa; otherwise, targets must be the same.
3756          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3757       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3758           || (target_cmp = comp_target_types (type, rhstype, 0))
3759           || is_opaque_pointer
3760           || (c_common_unsigned_type (mvl)
3761               == c_common_unsigned_type (mvr)))
3762         {
3763           if (pedantic
3764               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3765                   ||
3766                   (VOID_TYPE_P (ttr)
3767                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3768                       which are not ANSI null ptr constants.  */
3769                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3770                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3771             WARN_FOR_ASSIGNMENT (N_("ISO C forbids passing argument %d of "
3772                                     "%qE between function pointer "
3773                                     "and %<void *%>"),
3774                                  N_("ISO C forbids assignment between "
3775                                     "function pointer and %<void *%>"),
3776                                  N_("ISO C forbids initialization between "
3777                                     "function pointer and %<void *%>"),
3778                                  N_("ISO C forbids return between function "
3779                                     "pointer and %<void *%>"));
3780           /* Const and volatile mean something different for function types,
3781              so the usual warnings are not appropriate.  */
3782           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3783                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3784             {
3785               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3786                 WARN_FOR_ASSIGNMENT (N_("passing argument %d of %qE discards "
3787                                         "qualifiers from pointer target type"),
3788                                      N_("assignment discards qualifiers "
3789                                         "from pointer target type"),
3790                                      N_("initialization discards qualifiers "
3791                                         "from pointer target type"),
3792                                      N_("return discards qualifiers from "
3793                                         "pointer target type"));
3794               /* If this is not a case of ignoring a mismatch in signedness,
3795                  no warning.  */
3796               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3797                        || target_cmp)
3798                 ;
3799               /* If there is a mismatch, do warn.  */
3800               else if (warn_pointer_sign)
3801                 WARN_FOR_ASSIGNMENT (N_("pointer targets in passing argument "
3802                                         "%d of %qE differ in signedness"),
3803                                      N_("pointer targets in assignment "
3804                                         "differ in signedness"),
3805                                      N_("pointer targets in initialization "
3806                                         "differ in signedness"),
3807                                      N_("pointer targets in return differ "
3808                                         "in signedness"));
3809             }
3810           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3811                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3812             {
3813               /* Because const and volatile on functions are restrictions
3814                  that say the function will not do certain things,
3815                  it is okay to use a const or volatile function
3816                  where an ordinary one is wanted, but not vice-versa.  */
3817               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3818                 WARN_FOR_ASSIGNMENT (N_("passing argument %d of %qE makes "
3819                                         "qualified function pointer "
3820                                         "from unqualified"),
3821                                      N_("assignment makes qualified function "
3822                                         "pointer from unqualified"),
3823                                      N_("initialization makes qualified "
3824                                         "function pointer from unqualified"),
3825                                      N_("return makes qualified function "
3826                                         "pointer from unqualified"));
3827             }
3828         }
3829       else
3830         WARN_FOR_ASSIGNMENT (N_("passing argument %d of %qE from "
3831                                 "incompatible pointer type"),
3832                              N_("assignment from incompatible pointer type"),
3833                              N_("initialization from incompatible "
3834                                 "pointer type"),
3835                              N_("return from incompatible pointer type"));
3836       return convert (type, rhs);
3837     }
3838   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3839     {
3840       /* ??? This should not be an error when inlining calls to
3841          unprototyped functions.  */
3842       error ("invalid use of non-lvalue array");
3843       return error_mark_node;
3844     }
3845   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3846     {
3847       /* An explicit constant 0 can convert to a pointer,
3848          or one that results from arithmetic, even including
3849          a cast to integer type.  */
3850       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3851           &&
3852           !(TREE_CODE (rhs) == NOP_EXPR
3853             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3854             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3855             && integer_zerop (TREE_OPERAND (rhs, 0))))
3856         WARN_FOR_ASSIGNMENT (N_("passing argument %d of %qE makes "
3857                                 "pointer from integer without a cast"),
3858                              N_("assignment makes pointer from integer "
3859                                 "without a cast"),
3860                              N_("initialization makes pointer from "
3861                                 "integer without a cast"),
3862                              N_("return makes pointer from integer "
3863                                 "without a cast"));
3864
3865       return convert (type, rhs);
3866     }
3867   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3868     {
3869       WARN_FOR_ASSIGNMENT (N_("passing argument %d of %qE makes integer "
3870                               "from pointer without a cast"),
3871                            N_("assignment makes integer from pointer "
3872                               "without a cast"),
3873                            N_("initialization makes integer from pointer "
3874                               "without a cast"),
3875                            N_("return makes integer from pointer "
3876                               "without a cast"));
3877       return convert (type, rhs);
3878     }
3879   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3880     return convert (type, rhs);
3881
3882   switch (errtype)
3883     {
3884     case ic_argpass:
3885     case ic_argpass_nonproto:
3886       /* ??? This should not be an error when inlining calls to
3887          unprototyped functions.  */
3888       error ("incompatible type for argument %d of %qE", parmnum, rname);
3889       break;
3890     case ic_assign:
3891       error ("incompatible types in assignment");
3892       break;
3893     case ic_init:
3894       error ("incompatible types in initialization");
3895       break;
3896     case ic_return:
3897       error ("incompatible types in return");
3898       break;
3899     default:
3900       gcc_unreachable ();
3901     }
3902
3903   return error_mark_node;
3904 }
3905
3906 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
3907    is used for error and waring reporting and indicates which argument
3908    is being processed.  */
3909
3910 tree
3911 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
3912 {
3913   tree ret, type;
3914
3915   /* If FN was prototyped, the value has been converted already
3916      in convert_arguments.  */
3917   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
3918     return value;
3919
3920   type = TREE_TYPE (parm);
3921   ret = convert_for_assignment (type, value,
3922                                 ic_argpass_nonproto, fn,
3923                                 fn, argnum);
3924   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
3925       && INTEGRAL_TYPE_P (type)
3926       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3927     ret = default_conversion (ret);
3928   return ret;
3929 }
3930 \f
3931 /* If VALUE is a compound expr all of whose expressions are constant, then
3932    return its value.  Otherwise, return error_mark_node.
3933
3934    This is for handling COMPOUND_EXPRs as initializer elements
3935    which is allowed with a warning when -pedantic is specified.  */
3936
3937 static tree
3938 valid_compound_expr_initializer (tree value, tree endtype)
3939 {
3940   if (TREE_CODE (value) == COMPOUND_EXPR)
3941     {
3942       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
3943           == error_mark_node)
3944         return error_mark_node;
3945       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
3946                                               endtype);
3947     }
3948   else if (!initializer_constant_valid_p (value, endtype))
3949     return error_mark_node;
3950   else
3951     return value;
3952 }
3953 \f
3954 /* Perform appropriate conversions on the initial value of a variable,
3955    store it in the declaration DECL,
3956    and print any error messages that are appropriate.
3957    If the init is invalid, store an ERROR_MARK.  */
3958
3959 void
3960 store_init_value (tree decl, tree init)
3961 {
3962   tree value, type;
3963
3964   /* If variable's type was invalidly declared, just ignore it.  */
3965
3966   type = TREE_TYPE (decl);
3967   if (TREE_CODE (type) == ERROR_MARK)
3968     return;
3969
3970   /* Digest the specified initializer into an expression.  */
3971
3972   value = digest_init (type, init, true, TREE_STATIC (decl));
3973
3974   /* Store the expression if valid; else report error.  */
3975
3976   if (warn_traditional && !in_system_header
3977       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
3978     warning (0, "traditional C rejects automatic aggregate initialization");
3979
3980   DECL_INITIAL (decl) = value;
3981
3982   /* ANSI wants warnings about out-of-range constant initializers.  */
3983   STRIP_TYPE_NOPS (value);
3984   constant_expression_warning (value);
3985
3986   /* Check if we need to set array size from compound literal size.  */
3987   if (TREE_CODE (type) == ARRAY_TYPE
3988       && TYPE_DOMAIN (type) == 0
3989       && value != error_mark_node)
3990     {
3991       tree inside_init = init;
3992
3993       STRIP_TYPE_NOPS (inside_init);
3994       inside_init = fold (inside_init);
3995
3996       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
3997         {
3998           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
3999
4000           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4001             {
4002               /* For int foo[] = (int [3]){1}; we need to set array size
4003                  now since later on array initializer will be just the
4004                  brace enclosed list of the compound literal.  */
4005               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4006               layout_type (type);
4007               layout_decl (decl, 0);
4008             }
4009         }
4010     }
4011 }
4012 \f
4013 /* Methods for storing and printing names for error messages.  */
4014
4015 /* Implement a spelling stack that allows components of a name to be pushed
4016    and popped.  Each element on the stack is this structure.  */
4017
4018 struct spelling
4019 {
4020   int kind;
4021   union
4022     {
4023       int i;
4024       const char *s;
4025     } u;
4026 };
4027
4028 #define SPELLING_STRING 1
4029 #define SPELLING_MEMBER 2
4030 #define SPELLING_BOUNDS 3
4031
4032 static struct spelling *spelling;       /* Next stack element (unused).  */
4033 static struct spelling *spelling_base;  /* Spelling stack base.  */
4034 static int spelling_size;               /* Size of the spelling stack.  */
4035
4036 /* Macros to save and restore the spelling stack around push_... functions.
4037    Alternative to SAVE_SPELLING_STACK.  */
4038
4039 #define SPELLING_DEPTH() (spelling - spelling_base)
4040 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4041
4042 /* Push an element on the spelling stack with type KIND and assign VALUE
4043    to MEMBER.  */
4044
4045 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4046 {                                                                       \
4047   int depth = SPELLING_DEPTH ();                                        \
4048                                                                         \
4049   if (depth >= spelling_size)                                           \
4050     {                                                                   \
4051       spelling_size += 10;                                              \
4052       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4053                                   spelling_size);                       \
4054       RESTORE_SPELLING_DEPTH (depth);                                   \
4055     }                                                                   \
4056                                                                         \
4057   spelling->kind = (KIND);                                              \
4058   spelling->MEMBER = (VALUE);                                           \
4059   spelling++;                                                           \
4060 }
4061
4062 /* Push STRING on the stack.  Printed literally.  */
4063
4064 static void
4065 push_string (const char *string)
4066 {
4067   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4068 }
4069
4070 /* Push a member name on the stack.  Printed as '.' STRING.  */
4071
4072 static void
4073 push_member_name (tree decl)
4074 {
4075   const char *const string
4076     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4077   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4078 }
4079
4080 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4081
4082 static void
4083 push_array_bounds (int bounds)
4084 {
4085   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4086 }
4087
4088 /* Compute the maximum size in bytes of the printed spelling.  */
4089
4090 static int
4091 spelling_length (void)
4092 {
4093   int size = 0;
4094   struct spelling *p;
4095
4096   for (p = spelling_base; p < spelling; p++)
4097     {
4098       if (p->kind == SPELLING_BOUNDS)
4099         size += 25;
4100       else
4101         size += strlen (p->u.s) + 1;
4102     }
4103
4104   return size;
4105 }
4106
4107 /* Print the spelling to BUFFER and return it.  */
4108
4109 static char *
4110 print_spelling (char *buffer)
4111 {
4112   char *d = buffer;
4113   struct spelling *p;
4114
4115   for (p = spelling_base; p < spelling; p++)
4116     if (p->kind == SPELLING_BOUNDS)
4117       {
4118         sprintf (d, "[%d]", p->u.i);
4119         d += strlen (d);
4120       }
4121     else
4122       {
4123         const char *s;
4124         if (p->kind == SPELLING_MEMBER)
4125           *d++ = '.';
4126         for (s = p->u.s; (*d = *s++); d++)
4127           ;
4128       }
4129   *d++ = '\0';
4130   return buffer;
4131 }
4132
4133 /* Issue an error message for a bad initializer component.
4134    MSGID identifies the message.
4135    The component name is taken from the spelling stack.  */
4136
4137 void
4138 error_init (const char *msgid)
4139 {
4140   char *ofwhat;
4141
4142   error ("%s", _(msgid));
4143   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4144   if (*ofwhat)
4145     error ("(near initialization for %qs)", ofwhat);
4146 }
4147
4148 /* Issue a pedantic warning for a bad initializer component.
4149    MSGID identifies the message.
4150    The component name is taken from the spelling stack.  */
4151
4152 void
4153 pedwarn_init (const char *msgid)
4154 {
4155   char *ofwhat;
4156
4157   pedwarn ("%s", _(msgid));
4158   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4159   if (*ofwhat)
4160     pedwarn ("(near initialization for %qs)", ofwhat);
4161 }
4162
4163 /* Issue a warning for a bad initializer component.
4164    MSGID identifies the message.
4165    The component name is taken from the spelling stack.  */
4166
4167 static void
4168 warning_init (const char *msgid)
4169 {
4170   char *ofwhat;
4171
4172   warning (0, "%s", _(msgid));
4173   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4174   if (*ofwhat)
4175     warning (0, "(near initialization for %qs)", ofwhat);
4176 }
4177 \f
4178 /* If TYPE is an array type and EXPR is a parenthesized string
4179    constant, warn if pedantic that EXPR is being used to initialize an
4180    object of type TYPE.  */
4181
4182 void
4183 maybe_warn_string_init (tree type, struct c_expr expr)
4184 {
4185   if (pedantic
4186       && TREE_CODE (type) == ARRAY_TYPE
4187       && TREE_CODE (expr.value) == STRING_CST
4188       && expr.original_code != STRING_CST)
4189     pedwarn_init ("array initialized from parenthesized string constant");
4190 }
4191
4192 /* Digest the parser output INIT as an initializer for type TYPE.
4193    Return a C expression of type TYPE to represent the initial value.
4194
4195    If INIT is a string constant, STRICT_STRING is true if it is
4196    unparenthesized or we should not warn here for it being parenthesized.
4197    For other types of INIT, STRICT_STRING is not used.
4198
4199    REQUIRE_CONSTANT requests an error if non-constant initializers or
4200    elements are seen.  */
4201
4202 static tree
4203 digest_init (tree type, tree init, bool strict_string, int require_constant)
4204 {
4205   enum tree_code code = TREE_CODE (type);
4206   tree inside_init = init;
4207
4208   if (type == error_mark_node
4209       || init == error_mark_node
4210       || TREE_TYPE (init) == error_mark_node)
4211     return error_mark_node;
4212
4213   STRIP_TYPE_NOPS (inside_init);
4214
4215   inside_init = fold (inside_init);
4216
4217   /* Initialization of an array of chars from a string constant
4218      optionally enclosed in braces.  */
4219
4220   if (code == ARRAY_TYPE && inside_init
4221       && TREE_CODE (inside_init) == STRING_CST)
4222     {
4223       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4224       /* Note that an array could be both an array of character type
4225          and an array of wchar_t if wchar_t is signed char or unsigned
4226          char.  */
4227       bool char_array = (typ1 == char_type_node
4228                          || typ1 == signed_char_type_node
4229                          || typ1 == unsigned_char_type_node);
4230       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4231       if (char_array || wchar_array)
4232         {
4233           struct c_expr expr;
4234           bool char_string;
4235           expr.value = inside_init;
4236           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4237           maybe_warn_string_init (type, expr);
4238
4239           char_string
4240             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4241                == char_type_node);
4242
4243           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4244                          TYPE_MAIN_VARIANT (type)))
4245             return inside_init;
4246
4247           if (!wchar_array && !char_string)
4248             {
4249               error_init ("char-array initialized from wide string");
4250               return error_mark_node;
4251             }
4252           if (char_string && !char_array)
4253             {
4254               error_init ("wchar_t-array initialized from non-wide string");
4255               return error_mark_node;
4256             }
4257
4258           TREE_TYPE (inside_init) = type;
4259           if (TYPE_DOMAIN (type) != 0
4260               && TYPE_SIZE (type) != 0
4261               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4262               /* Subtract 1 (or sizeof (wchar_t))
4263                  because it's ok to ignore the terminating null char
4264                  that is counted in the length of the constant.  */
4265               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4266                                        TREE_STRING_LENGTH (inside_init)
4267                                        - ((TYPE_PRECISION (typ1)
4268                                            != TYPE_PRECISION (char_type_node))
4269                                           ? (TYPE_PRECISION (wchar_type_node)
4270                                              / BITS_PER_UNIT)
4271                                           : 1)))
4272             pedwarn_init ("initializer-string for array of chars is too long");
4273
4274           return inside_init;
4275         }
4276       else if (INTEGRAL_TYPE_P (typ1))
4277         {
4278           error_init ("array of inappropriate type initialized "
4279                       "from string constant");
4280           return error_mark_node;
4281         }
4282     }
4283
4284   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4285      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4286      below and handle as a constructor.  */
4287   if (code == VECTOR_TYPE
4288       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4289       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4290       && TREE_CONSTANT (inside_init))
4291     {
4292       if (TREE_CODE (inside_init) == VECTOR_CST
4293           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4294                         TYPE_MAIN_VARIANT (type)))
4295         return inside_init;
4296
4297       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4298         {
4299           tree link;
4300
4301           /* Iterate through elements and check if all constructor
4302              elements are *_CSTs.  */
4303           for (link = CONSTRUCTOR_ELTS (inside_init);
4304                link;
4305                link = TREE_CHAIN (link))
4306             if (! CONSTANT_CLASS_P (TREE_VALUE (link)))
4307               break;
4308
4309           if (link == NULL)
4310             return build_vector (type, CONSTRUCTOR_ELTS (inside_init));
4311         }
4312     }
4313
4314   /* Any type can be initialized
4315      from an expression of the same type, optionally with braces.  */
4316
4317   if (inside_init && TREE_TYPE (inside_init) != 0
4318       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4319                      TYPE_MAIN_VARIANT (type))
4320           || (code == ARRAY_TYPE
4321               && comptypes (TREE_TYPE (inside_init), type))
4322           || (code == VECTOR_TYPE
4323               && comptypes (TREE_TYPE (inside_init), type))
4324           || (code == POINTER_TYPE
4325               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4326               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4327                             TREE_TYPE (type)))
4328           || (code == POINTER_TYPE
4329               && TREE_CODE (TREE_TYPE (inside_init)) == FUNCTION_TYPE
4330               && comptypes (TREE_TYPE (inside_init),
4331                             TREE_TYPE (type)))))
4332     {
4333       if (code == POINTER_TYPE)
4334         {
4335           inside_init = default_function_array_conversion (inside_init);
4336
4337           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4338             {
4339               error_init ("invalid use of non-lvalue array");
4340               return error_mark_node;
4341             }
4342          }
4343
4344       if (code == VECTOR_TYPE)
4345         /* Although the types are compatible, we may require a
4346            conversion.  */
4347         inside_init = convert (type, inside_init);
4348
4349       if (require_constant && !flag_isoc99
4350           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4351         {
4352           /* As an extension, allow initializing objects with static storage
4353              duration with compound literals (which are then treated just as
4354              the brace enclosed list they contain).  */
4355           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4356           inside_init = DECL_INITIAL (decl);
4357         }
4358
4359       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4360           && TREE_CODE (inside_init) != CONSTRUCTOR)
4361         {
4362           error_init ("array initialized from non-constant array expression");
4363           return error_mark_node;
4364         }
4365
4366       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4367         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4368
4369       /* Compound expressions can only occur here if -pedantic or
4370          -pedantic-errors is specified.  In the later case, we always want
4371          an error.  In the former case, we simply want a warning.  */
4372       if (require_constant && pedantic
4373           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4374         {
4375           inside_init
4376             = valid_compound_expr_initializer (inside_init,
4377                                                TREE_TYPE (inside_init));
4378           if (inside_init == error_mark_node)
4379             error_init ("initializer element is not constant");
4380           else
4381             pedwarn_init ("initializer element is not constant");
4382           if (flag_pedantic_errors)
4383             inside_init = error_mark_node;
4384         }
4385       else if (require_constant
4386                && !initializer_constant_valid_p (inside_init,
4387                                                  TREE_TYPE (inside_init)))
4388         {
4389           error_init ("initializer element is not constant");
4390           inside_init = error_mark_node;
4391         }
4392
4393       return inside_init;
4394     }
4395
4396   /* Handle scalar types, including conversions.  */
4397
4398   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4399       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4400       || code == VECTOR_TYPE)
4401     {
4402       /* Note that convert_for_assignment calls default_conversion
4403          for arrays and functions.  We must not call it in the
4404          case where inside_init is a null pointer constant.  */
4405       inside_init
4406         = convert_for_assignment (type, init, ic_init,
4407                                   NULL_TREE, NULL_TREE, 0);
4408
4409       /* Check to see if we have already given an error message.  */
4410       if (inside_init == error_mark_node)
4411         ;
4412       else if (require_constant && !TREE_CONSTANT (inside_init))
4413         {
4414           error_init ("initializer element is not constant");
4415           inside_init = error_mark_node;
4416         }
4417       else if (require_constant
4418                && !initializer_constant_valid_p (inside_init,
4419                                                  TREE_TYPE (inside_init)))
4420         {
4421           error_init ("initializer element is not computable at load time");
4422           inside_init = error_mark_node;
4423         }
4424
4425       return inside_init;
4426     }
4427
4428   /* Come here only for records and arrays.  */
4429
4430   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4431     {
4432       error_init ("variable-sized object may not be initialized");
4433       return error_mark_node;
4434     }
4435
4436   error_init ("invalid initializer");
4437   return error_mark_node;
4438 }
4439 \f
4440 /* Handle initializers that use braces.  */
4441
4442 /* Type of object we are accumulating a constructor for.
4443    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4444 static tree constructor_type;
4445
4446 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4447    left to fill.  */
4448 static tree constructor_fields;
4449
4450 /* For an ARRAY_TYPE, this is the specified index
4451    at which to store the next element we get.  */
4452 static tree constructor_index;
4453
4454 /* For an ARRAY_TYPE, this is the maximum index.  */
4455 static tree constructor_max_index;
4456
4457 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4458 static tree constructor_unfilled_fields;
4459
4460 /* For an ARRAY_TYPE, this is the index of the first element
4461    not yet written out.  */
4462 static tree constructor_unfilled_index;
4463
4464 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4465    This is so we can generate gaps between fields, when appropriate.  */
4466 static tree constructor_bit_index;
4467
4468 /* If we are saving up the elements rather than allocating them,
4469    this is the list of elements so far (in reverse order,
4470    most recent first).  */
4471 static tree constructor_elements;
4472
4473 /* 1 if constructor should be incrementally stored into a constructor chain,
4474    0 if all the elements should be kept in AVL tree.  */
4475 static int constructor_incremental;
4476
4477 /* 1 if so far this constructor's elements are all compile-time constants.  */
4478 static int constructor_constant;
4479
4480 /* 1 if so far this constructor's elements are all valid address constants.  */
4481 static int constructor_simple;
4482
4483 /* 1 if this constructor is erroneous so far.  */
4484 static int constructor_erroneous;
4485
4486 /* Structure for managing pending initializer elements, organized as an
4487    AVL tree.  */
4488
4489 struct init_node
4490 {
4491   struct init_node *left, *right;
4492   struct init_node *parent;
4493   int balance;
4494   tree purpose;
4495   tree value;
4496 };
4497
4498 /* Tree of pending elements at this constructor level.
4499    These are elements encountered out of order
4500    which belong at places we haven't reached yet in actually
4501    writing the output.
4502    Will never hold tree nodes across GC runs.  */
4503 static struct init_node *constructor_pending_elts;
4504
4505 /* The SPELLING_DEPTH of this constructor.  */
4506 static int constructor_depth;
4507
4508 /* DECL node for which an initializer is being read.
4509    0 means we are reading a constructor expression
4510    such as (struct foo) {...}.  */
4511 static tree constructor_decl;
4512
4513 /* Nonzero if this is an initializer for a top-level decl.  */
4514 static int constructor_top_level;
4515
4516 /* Nonzero if there were any member designators in this initializer.  */
4517 static int constructor_designated;
4518
4519 /* Nesting depth of designator list.  */
4520 static int designator_depth;
4521
4522 /* Nonzero if there were diagnosed errors in this designator list.  */
4523 static int designator_errorneous;
4524
4525 \f
4526 /* This stack has a level for each implicit or explicit level of
4527    structuring in the initializer, including the outermost one.  It
4528    saves the values of most of the variables above.  */
4529
4530 struct constructor_range_stack;
4531
4532 struct constructor_stack
4533 {
4534   struct constructor_stack *next;
4535   tree type;
4536   tree fields;
4537   tree index;
4538   tree max_index;
4539   tree unfilled_index;
4540   tree unfilled_fields;
4541   tree bit_index;
4542   tree elements;
4543   struct init_node *pending_elts;
4544   int offset;
4545   int depth;
4546   /* If value nonzero, this value should replace the entire
4547      constructor at this level.  */
4548   struct c_expr replacement_value;
4549   struct constructor_range_stack *range_stack;
4550   char constant;
4551   char simple;
4552   char implicit;
4553   char erroneous;
4554   char outer;
4555   char incremental;
4556   char designated;
4557 };
4558
4559 static struct constructor_stack *constructor_stack;
4560
4561 /* This stack represents designators from some range designator up to
4562    the last designator in the list.  */
4563
4564 struct constructor_range_stack
4565 {
4566   struct constructor_range_stack *next, *prev;
4567   struct constructor_stack *stack;
4568   tree range_start;
4569   tree index;
4570   tree range_end;
4571   tree fields;
4572 };
4573
4574 static struct constructor_range_stack *constructor_range_stack;
4575
4576 /* This stack records separate initializers that are nested.
4577    Nested initializers can't happen in ANSI C, but GNU C allows them
4578    in cases like { ... (struct foo) { ... } ... }.  */
4579
4580 struct initializer_stack
4581 {
4582   struct initializer_stack *next;
4583   tree decl;
4584   struct constructor_stack *constructor_stack;
4585   struct constructor_range_stack *constructor_range_stack;
4586   tree elements;
4587   struct spelling *spelling;
4588   struct spelling *spelling_base;
4589   int spelling_size;
4590   char top_level;
4591   char require_constant_value;
4592   char require_constant_elements;
4593 };
4594
4595 static struct initializer_stack *initializer_stack;
4596 \f
4597 /* Prepare to parse and output the initializer for variable DECL.  */
4598
4599 void
4600 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4601 {
4602   const char *locus;
4603   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4604
4605   p->decl = constructor_decl;
4606   p->require_constant_value = require_constant_value;
4607   p->require_constant_elements = require_constant_elements;
4608   p->constructor_stack = constructor_stack;
4609   p->constructor_range_stack = constructor_range_stack;
4610   p->elements = constructor_elements;
4611   p->spelling = spelling;
4612   p->spelling_base = spelling_base;
4613   p->spelling_size = spelling_size;
4614   p->top_level = constructor_top_level;
4615   p->next = initializer_stack;
4616   initializer_stack = p;
4617
4618   constructor_decl = decl;
4619   constructor_designated = 0;
4620   constructor_top_level = top_level;
4621
4622   if (decl != 0 && decl != error_mark_node)
4623     {
4624       require_constant_value = TREE_STATIC (decl);
4625       require_constant_elements
4626         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4627            /* For a scalar, you can always use any value to initialize,
4628               even within braces.  */
4629            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4630                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4631                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4632                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4633       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4634     }
4635   else
4636     {
4637       require_constant_value = 0;
4638       require_constant_elements = 0;
4639       locus = "(anonymous)";
4640     }
4641
4642   constructor_stack = 0;
4643   constructor_range_stack = 0;
4644
4645   missing_braces_mentioned = 0;
4646
4647   spelling_base = 0;
4648   spelling_size = 0;
4649   RESTORE_SPELLING_DEPTH (0);
4650
4651   if (locus)
4652     push_string (locus);
4653 }
4654
4655 void
4656 finish_init (void)
4657 {
4658   struct initializer_stack *p = initializer_stack;
4659
4660   /* Free the whole constructor stack of this initializer.  */
4661   while (constructor_stack)
4662     {
4663       struct constructor_stack *q = constructor_stack;
4664       constructor_stack = q->next;
4665       free (q);
4666     }
4667
4668   gcc_assert (!constructor_range_stack);
4669
4670   /* Pop back to the data of the outer initializer (if any).  */
4671   free (spelling_base);
4672
4673   constructor_decl = p->decl;
4674   require_constant_value = p->require_constant_value;
4675   require_constant_elements = p->require_constant_elements;
4676   constructor_stack = p->constructor_stack;
4677   constructor_range_stack = p->constructor_range_stack;
4678   constructor_elements = p->elements;
4679   spelling = p->spelling;
4680   spelling_base = p->spelling_base;
4681   spelling_size = p->spelling_size;
4682   constructor_top_level = p->top_level;
4683   initializer_stack = p->next;
4684   free (p);
4685 }
4686 \f
4687 /* Call here when we see the initializer is surrounded by braces.
4688    This is instead of a call to push_init_level;
4689    it is matched by a call to pop_init_level.
4690
4691    TYPE is the type to initialize, for a constructor expression.
4692    For an initializer for a decl, TYPE is zero.  */
4693
4694 void
4695 really_start_incremental_init (tree type)
4696 {
4697   struct constructor_stack *p = XNEW (struct constructor_stack);
4698
4699   if (type == 0)
4700     type = TREE_TYPE (constructor_decl);
4701
4702   if (targetm.vector_opaque_p (type))
4703     error ("opaque vector types cannot be initialized");
4704
4705   p->type = constructor_type;
4706   p->fields = constructor_fields;
4707   p->index = constructor_index;
4708   p->max_index = constructor_max_index;
4709   p->unfilled_index = constructor_unfilled_index;
4710   p->unfilled_fields = constructor_unfilled_fields;
4711   p->bit_index = constructor_bit_index;
4712   p->elements = constructor_elements;
4713   p->constant = constructor_constant;
4714   p->simple = constructor_simple;
4715   p->erroneous = constructor_erroneous;
4716   p->pending_elts = constructor_pending_elts;
4717   p->depth = constructor_depth;
4718   p->replacement_value.value = 0;
4719   p->replacement_value.original_code = ERROR_MARK;
4720   p->implicit = 0;
4721   p->range_stack = 0;
4722   p->outer = 0;
4723   p->incremental = constructor_incremental;
4724   p->designated = constructor_designated;
4725   p->next = 0;
4726   constructor_stack = p;
4727
4728   constructor_constant = 1;
4729   constructor_simple = 1;
4730   constructor_depth = SPELLING_DEPTH ();
4731   constructor_elements = 0;
4732   constructor_pending_elts = 0;
4733   constructor_type = type;
4734   constructor_incremental = 1;
4735   constructor_designated = 0;
4736   designator_depth = 0;
4737   designator_errorneous = 0;
4738
4739   if (TREE_CODE (constructor_type) == RECORD_TYPE
4740       || TREE_CODE (constructor_type) == UNION_TYPE)
4741     {
4742       constructor_fields = TYPE_FIELDS (constructor_type);
4743       /* Skip any nameless bit fields at the beginning.  */
4744       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4745              && DECL_NAME (constructor_fields) == 0)
4746         constructor_fields = TREE_CHAIN (constructor_fields);
4747
4748       constructor_unfilled_fields = constructor_fields;
4749       constructor_bit_index = bitsize_zero_node;
4750     }
4751   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4752     {
4753       if (TYPE_DOMAIN (constructor_type))
4754         {
4755           constructor_max_index
4756             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4757
4758           /* Detect non-empty initializations of zero-length arrays.  */
4759           if (constructor_max_index == NULL_TREE
4760               && TYPE_SIZE (constructor_type))
4761             constructor_max_index = build_int_cst (NULL_TREE, -1);
4762
4763           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4764              to initialize VLAs will cause a proper error; avoid tree
4765              checking errors as well by setting a safe value.  */
4766           if (constructor_max_index
4767               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4768             constructor_max_index = build_int_cst (NULL_TREE, -1);
4769
4770           constructor_index
4771             = convert (bitsizetype,
4772                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4773         }
4774       else
4775         {
4776           constructor_index = bitsize_zero_node;
4777           constructor_max_index = NULL_TREE;
4778         }
4779
4780       constructor_unfilled_index = constructor_index;
4781     }
4782   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4783     {
4784       /* Vectors are like simple fixed-size arrays.  */
4785       constructor_max_index =
4786         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4787       constructor_index = convert (bitsizetype, bitsize_zero_node);
4788       constructor_unfilled_index = constructor_index;
4789     }
4790   else
4791     {
4792       /* Handle the case of int x = {5}; */
4793       constructor_fields = constructor_type;
4794       constructor_unfilled_fields = constructor_type;
4795     }
4796 }
4797 \f
4798 /* Push down into a subobject, for initialization.
4799    If this is for an explicit set of braces, IMPLICIT is 0.
4800    If it is because the next element belongs at a lower level,
4801    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4802
4803 void
4804 push_init_level (int implicit)
4805 {
4806   struct constructor_stack *p;
4807   tree value = NULL_TREE;
4808
4809   /* If we've exhausted any levels that didn't have braces,
4810      pop them now.  */
4811   while (constructor_stack->implicit)
4812     {
4813       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4814            || TREE_CODE (constructor_type) == UNION_TYPE)
4815           && constructor_fields == 0)
4816         process_init_element (pop_init_level (1));
4817       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4818                && constructor_max_index
4819                && tree_int_cst_lt (constructor_max_index, constructor_index))
4820         process_init_element (pop_init_level (1));
4821       else
4822         break;
4823     }
4824
4825   /* Unless this is an explicit brace, we need to preserve previous
4826      content if any.  */
4827   if (implicit)
4828     {
4829       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4830            || TREE_CODE (constructor_type) == UNION_TYPE)
4831           && constructor_fields)
4832         value = find_init_member (constructor_fields);
4833       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4834         value = find_init_member (constructor_index);
4835     }
4836
4837   p = XNEW (struct constructor_stack);
4838   p->type = constructor_type;
4839   p->fields = constructor_fields;
4840   p->index = constructor_index;
4841   p->max_index = constructor_max_index;
4842   p->unfilled_index = constructor_unfilled_index;
4843   p->unfilled_fields = constructor_unfilled_fields;
4844   p->bit_index = constructor_bit_index;
4845   p->elements = constructor_elements;
4846   p->constant = constructor_constant;
4847   p->simple = constructor_simple;
4848   p->erroneous = constructor_erroneous;
4849   p->pending_elts = constructor_pending_elts;
4850   p->depth = constructor_depth;
4851   p->replacement_value.value = 0;
4852   p->replacement_value.original_code = ERROR_MARK;
4853   p->implicit = implicit;
4854   p->outer = 0;
4855   p->incremental = constructor_incremental;
4856   p->designated = constructor_designated;
4857   p->next = constructor_stack;
4858   p->range_stack = 0;
4859   constructor_stack = p;
4860
4861   constructor_constant = 1;
4862   constructor_simple = 1;
4863   constructor_depth = SPELLING_DEPTH ();
4864   constructor_elements = 0;
4865   constructor_incremental = 1;
4866   constructor_designated = 0;
4867   constructor_pending_elts = 0;
4868   if (!implicit)
4869     {
4870       p->range_stack = constructor_range_stack;
4871       constructor_range_stack = 0;
4872       designator_depth = 0;
4873       designator_errorneous = 0;
4874     }
4875
4876   /* Don't die if an entire brace-pair level is superfluous
4877      in the containing level.  */
4878   if (constructor_type == 0)
4879     ;
4880   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4881            || TREE_CODE (constructor_type) == UNION_TYPE)
4882     {
4883       /* Don't die if there are extra init elts at the end.  */
4884       if (constructor_fields == 0)
4885         constructor_type = 0;
4886       else
4887         {
4888           constructor_type = TREE_TYPE (constructor_fields);
4889           push_member_name (constructor_fields);
4890           constructor_depth++;
4891         }
4892     }
4893   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4894     {
4895       constructor_type = TREE_TYPE (constructor_type);
4896       push_array_bounds (tree_low_cst (constructor_index, 0));
4897       constructor_depth++;
4898     }
4899
4900   if (constructor_type == 0)
4901     {
4902       error_init ("extra brace group at end of initializer");
4903       constructor_fields = 0;
4904       constructor_unfilled_fields = 0;
4905       return;
4906     }
4907
4908   if (value && TREE_CODE (value) == CONSTRUCTOR)
4909     {
4910       constructor_constant = TREE_CONSTANT (value);
4911       constructor_simple = TREE_STATIC (value);
4912       constructor_elements = CONSTRUCTOR_ELTS (value);
4913       if (constructor_elements
4914           && (TREE_CODE (constructor_type) == RECORD_TYPE
4915               || TREE_CODE (constructor_type) == ARRAY_TYPE))
4916         set_nonincremental_init ();
4917     }
4918
4919   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
4920     {
4921       missing_braces_mentioned = 1;
4922       warning_init ("missing braces around initializer");
4923     }
4924
4925   if (TREE_CODE (constructor_type) == RECORD_TYPE
4926            || TREE_CODE (constructor_type) == UNION_TYPE)
4927     {
4928       constructor_fields = TYPE_FIELDS (constructor_type);
4929       /* Skip any nameless bit fields at the beginning.  */
4930       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4931              && DECL_NAME (constructor_fields) == 0)
4932         constructor_fields = TREE_CHAIN (constructor_fields);
4933
4934       constructor_unfilled_fields = constructor_fields;
4935       constructor_bit_index = bitsize_zero_node;
4936     }
4937   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4938     {
4939       /* Vectors are like simple fixed-size arrays.  */
4940       constructor_max_index =
4941         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4942       constructor_index = convert (bitsizetype, integer_zero_node);
4943       constructor_unfilled_index = constructor_index;
4944     }
4945   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4946     {
4947       if (TYPE_DOMAIN (constructor_type))
4948         {
4949           constructor_max_index
4950             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4951
4952           /* Detect non-empty initializations of zero-length arrays.  */
4953           if (constructor_max_index == NULL_TREE
4954               && TYPE_SIZE (constructor_type))
4955             constructor_max_index = build_int_cst (NULL_TREE, -1);
4956
4957           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4958              to initialize VLAs will cause a proper error; avoid tree
4959              checking errors as well by setting a safe value.  */
4960           if (constructor_max_index
4961               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4962             constructor_max_index = build_int_cst (NULL_TREE, -1);
4963
4964           constructor_index
4965             = convert (bitsizetype,
4966                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4967         }
4968       else
4969         constructor_index = bitsize_zero_node;
4970
4971       constructor_unfilled_index = constructor_index;
4972       if (value && TREE_CODE (value) == STRING_CST)
4973         {
4974           /* We need to split the char/wchar array into individual
4975              characters, so that we don't have to special case it
4976              everywhere.  */
4977           set_nonincremental_init_from_string (value);
4978         }
4979     }
4980   else
4981     {
4982       if (constructor_type != error_mark_node)
4983         warning_init ("braces around scalar initializer");
4984       constructor_fields = constructor_type;
4985       constructor_unfilled_fields = constructor_type;
4986     }
4987 }
4988
4989 /* At the end of an implicit or explicit brace level,
4990    finish up that level of constructor.  If a single expression
4991    with redundant braces initialized that level, return the
4992    c_expr structure for that expression.  Otherwise, the original_code
4993    element is set to ERROR_MARK.
4994    If we were outputting the elements as they are read, return 0 as the value
4995    from inner levels (process_init_element ignores that),
4996    but return error_mark_node as the value from the outermost level
4997    (that's what we want to put in DECL_INITIAL).
4998    Otherwise, return a CONSTRUCTOR expression as the value.  */
4999
5000 struct c_expr
5001 pop_init_level (int implicit)
5002 {
5003   struct constructor_stack *p;
5004   struct c_expr ret;
5005   ret.value = 0;
5006   ret.original_code = ERROR_MARK;
5007
5008   if (implicit == 0)
5009     {
5010       /* When we come to an explicit close brace,
5011          pop any inner levels that didn't have explicit braces.  */
5012       while (constructor_stack->implicit)
5013         process_init_element (pop_init_level (1));
5014
5015       gcc_assert (!constructor_range_stack);
5016     }
5017
5018   /* Now output all pending elements.  */
5019   constructor_incremental = 1;
5020   output_pending_init_elements (1);
5021
5022   p = constructor_stack;
5023
5024   /* Error for initializing a flexible array member, or a zero-length
5025      array member in an inappropriate context.  */
5026   if (constructor_type && constructor_fields
5027       && TREE_CODE (constructor_type) == ARRAY_TYPE
5028       && TYPE_DOMAIN (constructor_type)
5029       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5030     {
5031       /* Silently discard empty initializations.  The parser will
5032          already have pedwarned for empty brackets.  */
5033       if (integer_zerop (constructor_unfilled_index))
5034         constructor_type = NULL_TREE;
5035       else
5036         {
5037           gcc_assert (!TYPE_SIZE (constructor_type));
5038
5039           if (constructor_depth > 2)
5040             error_init ("initialization of flexible array member in a nested context");
5041           else if (pedantic)
5042             pedwarn_init ("initialization of a flexible array member");
5043
5044           /* We have already issued an error message for the existence
5045              of a flexible array member not at the end of the structure.
5046              Discard the initializer so that we do not die later.  */
5047           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5048             constructor_type = NULL_TREE;
5049         }
5050     }
5051
5052   /* Warn when some struct elements are implicitly initialized to zero.  */
5053   if (warn_missing_field_initializers
5054       && constructor_type
5055       && TREE_CODE (constructor_type) == RECORD_TYPE
5056       && constructor_unfilled_fields)
5057     {
5058         /* Do not warn for flexible array members or zero-length arrays.  */
5059         while (constructor_unfilled_fields
5060                && (!DECL_SIZE (constructor_unfilled_fields)
5061                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5062           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5063
5064         /* Do not warn if this level of the initializer uses member
5065            designators; it is likely to be deliberate.  */
5066         if (constructor_unfilled_fields && !constructor_designated)
5067           {
5068             push_member_name (constructor_unfilled_fields);
5069             warning_init ("missing initializer");
5070             RESTORE_SPELLING_DEPTH (constructor_depth);
5071           }
5072     }
5073
5074   /* Pad out the end of the structure.  */
5075   if (p->replacement_value.value)
5076     /* If this closes a superfluous brace pair,
5077        just pass out the element between them.  */
5078     ret = p->replacement_value;
5079   else if (constructor_type == 0)
5080     ;
5081   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5082            && TREE_CODE (constructor_type) != UNION_TYPE
5083            && TREE_CODE (constructor_type) != ARRAY_TYPE
5084            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5085     {
5086       /* A nonincremental scalar initializer--just return
5087          the element, after verifying there is just one.  */
5088       if (constructor_elements == 0)
5089         {
5090           if (!constructor_erroneous)
5091             error_init ("empty scalar initializer");
5092           ret.value = error_mark_node;
5093         }
5094       else if (TREE_CHAIN (constructor_elements) != 0)
5095         {
5096           error_init ("extra elements in scalar initializer");
5097           ret.value = TREE_VALUE (constructor_elements);
5098         }
5099       else
5100         ret.value = TREE_VALUE (constructor_elements);
5101     }
5102   else
5103     {
5104       if (constructor_erroneous)
5105         ret.value = error_mark_node;
5106       else
5107         {
5108           ret.value = build_constructor (constructor_type,
5109                                          nreverse (constructor_elements));
5110           if (constructor_constant)
5111             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5112           if (constructor_constant && constructor_simple)
5113             TREE_STATIC (ret.value) = 1;
5114         }
5115     }
5116
5117   constructor_type = p->type;
5118   constructor_fields = p->fields;
5119   constructor_index = p->index;
5120   constructor_max_index = p->max_index;
5121   constructor_unfilled_index = p->unfilled_index;
5122   constructor_unfilled_fields = p->unfilled_fields;
5123   constructor_bit_index = p->bit_index;
5124   constructor_elements = p->elements;
5125   constructor_constant = p->constant;
5126   constructor_simple = p->simple;
5127   constructor_erroneous = p->erroneous;
5128   constructor_incremental = p->incremental;
5129   constructor_designated = p->designated;
5130   constructor_pending_elts = p->pending_elts;
5131   constructor_depth = p->depth;
5132   if (!p->implicit)
5133     constructor_range_stack = p->range_stack;
5134   RESTORE_SPELLING_DEPTH (constructor_depth);
5135
5136   constructor_stack = p->next;
5137   free (p);
5138
5139   if (ret.value == 0)
5140     {
5141       if (constructor_stack == 0)
5142         {
5143           ret.value = error_mark_node;
5144           return ret;
5145         }
5146       return ret;
5147     }
5148   return ret;
5149 }
5150
5151 /* Common handling for both array range and field name designators.
5152    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5153
5154 static int
5155 set_designator (int array)
5156 {
5157   tree subtype;
5158   enum tree_code subcode;
5159
5160   /* Don't die if an entire brace-pair level is superfluous
5161      in the containing level.  */
5162   if (constructor_type == 0)
5163     return 1;
5164
5165   /* If there were errors in this designator list already, bail out
5166      silently.  */
5167   if (designator_errorneous)
5168     return 1;
5169
5170   if (!designator_depth)
5171     {
5172       gcc_assert (!constructor_range_stack);
5173
5174       /* Designator list starts at the level of closest explicit
5175          braces.  */
5176       while (constructor_stack->implicit)
5177         process_init_element (pop_init_level (1));
5178       constructor_designated = 1;
5179       return 0;
5180     }
5181
5182   switch (TREE_CODE (constructor_type))
5183     {
5184     case  RECORD_TYPE:
5185     case  UNION_TYPE:
5186       subtype = TREE_TYPE (constructor_fields);
5187       if (subtype != error_mark_node)
5188         subtype = TYPE_MAIN_VARIANT (subtype);
5189       break;
5190     case ARRAY_TYPE:
5191       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5192       break;
5193     default:
5194       gcc_unreachable ();
5195     }
5196
5197   subcode = TREE_CODE (subtype);
5198   if (array && subcode != ARRAY_TYPE)
5199     {
5200       error_init ("array index in non-array initializer");
5201       return 1;
5202     }
5203   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5204     {
5205       error_init ("field name not in record or union initializer");
5206       return 1;
5207     }
5208
5209   constructor_designated = 1;
5210   push_init_level (2);
5211   return 0;
5212 }
5213
5214 /* If there are range designators in designator list, push a new designator
5215    to constructor_range_stack.  RANGE_END is end of such stack range or
5216    NULL_TREE if there is no range designator at this level.  */
5217
5218 static void
5219 push_range_stack (tree range_end)
5220 {
5221   struct constructor_range_stack *p;
5222
5223   p = GGC_NEW (struct constructor_range_stack);
5224   p->prev = constructor_range_stack;
5225   p->next = 0;
5226   p->fields = constructor_fields;
5227   p->range_start = constructor_index;
5228   p->index = constructor_index;
5229   p->stack = constructor_stack;
5230   p->range_end = range_end;
5231   if (constructor_range_stack)
5232     constructor_range_stack->next = p;
5233   constructor_range_stack = p;
5234 }
5235
5236 /* Within an array initializer, specify the next index to be initialized.
5237    FIRST is that index.  If LAST is nonzero, then initialize a range
5238    of indices, running from FIRST through LAST.  */
5239
5240 void
5241 set_init_index (tree first, tree last)
5242 {
5243   if (set_designator (1))
5244     return;
5245
5246   designator_errorneous = 1;
5247
5248   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5249       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5250     {
5251       error_init ("array index in initializer not of integer type");
5252       return;
5253     }
5254
5255   if (TREE_CODE (first) != INTEGER_CST)
5256     error_init ("nonconstant array index in initializer");
5257   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5258     error_init ("nonconstant array index in initializer");
5259   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5260     error_init ("array index in non-array initializer");
5261   else if (tree_int_cst_sgn (first) == -1)
5262     error_init ("array index in initializer exceeds array bounds");
5263   else if (constructor_max_index
5264            && tree_int_cst_lt (constructor_max_index, first))
5265     error_init ("array index in initializer exceeds array bounds");
5266   else
5267     {
5268       constructor_index = convert (bitsizetype, first);
5269
5270       if (last)
5271         {
5272           if (tree_int_cst_equal (first, last))
5273             last = 0;
5274           else if (tree_int_cst_lt (last, first))
5275             {
5276               error_init ("empty index range in initializer");
5277               last = 0;
5278             }
5279           else
5280             {
5281               last = convert (bitsizetype, last);
5282               if (constructor_max_index != 0
5283                   && tree_int_cst_lt (constructor_max_index, last))
5284                 {
5285                   error_init ("array index range in initializer exceeds array bounds");
5286                   last = 0;
5287                 }
5288             }
5289         }
5290
5291       designator_depth++;
5292       designator_errorneous = 0;
5293       if (constructor_range_stack || last)
5294         push_range_stack (last);
5295     }
5296 }
5297
5298 /* Within a struct initializer, specify the next field to be initialized.  */
5299
5300 void
5301 set_init_label (tree fieldname)
5302 {
5303   tree tail;
5304
5305   if (set_designator (0))
5306     return;
5307
5308   designator_errorneous = 1;
5309
5310   if (TREE_CODE (constructor_type) != RECORD_TYPE
5311       && TREE_CODE (constructor_type) != UNION_TYPE)
5312     {
5313       error_init ("field name not in record or union initializer");
5314       return;
5315     }
5316
5317   for (tail = TYPE_FIELDS (constructor_type); tail;
5318        tail = TREE_CHAIN (tail))
5319     {
5320       if (DECL_NAME (tail) == fieldname)
5321         break;
5322     }
5323
5324   if (tail == 0)
5325     error ("unknown field %qE specified in initializer", fieldname);
5326   else
5327     {
5328       constructor_fields = tail;
5329       designator_depth++;
5330       designator_errorneous = 0;
5331       if (constructor_range_stack)
5332         push_range_stack (NULL_TREE);
5333     }
5334 }
5335 \f
5336 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5337    identifies the initializer, either array index or field in a structure.
5338    VALUE is the value of that index or field.  */
5339
5340 static void
5341 add_pending_init (tree purpose, tree value)
5342 {
5343   struct init_node *p, **q, *r;
5344
5345   q = &constructor_pending_elts;
5346   p = 0;
5347
5348   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5349     {
5350       while (*q != 0)
5351         {
5352           p = *q;
5353           if (tree_int_cst_lt (purpose, p->purpose))
5354             q = &p->left;
5355           else if (tree_int_cst_lt (p->purpose, purpose))
5356             q = &p->right;
5357           else
5358             {
5359               if (TREE_SIDE_EFFECTS (p->value))
5360                 warning_init ("initialized field with side-effects overwritten");
5361               p->value = value;
5362               return;
5363             }
5364         }
5365     }
5366   else
5367     {
5368       tree bitpos;
5369
5370       bitpos = bit_position (purpose);
5371       while (*q != NULL)
5372         {
5373           p = *q;
5374           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5375             q = &p->left;
5376           else if (p->purpose != purpose)
5377             q = &p->right;
5378           else
5379             {
5380               if (TREE_SIDE_EFFECTS (p->value))
5381                 warning_init ("initialized field with side-effects overwritten");
5382               p->value = value;
5383               return;
5384             }
5385         }
5386     }
5387
5388   r = GGC_NEW (struct init_node);
5389   r->purpose = purpose;
5390   r->value = value;
5391
5392   *q = r;
5393   r->parent = p;
5394   r->left = 0;
5395   r->right = 0;
5396   r->balance = 0;
5397
5398   while (p)
5399     {
5400       struct init_node *s;
5401
5402       if (r == p->left)
5403         {
5404           if (p->balance == 0)
5405             p->balance = -1;
5406           else if (p->balance < 0)
5407             {
5408               if (r->balance < 0)
5409                 {
5410                   /* L rotation.  */
5411                   p->left = r->right;
5412                   if (p->left)
5413                     p->left->parent = p;
5414                   r->right = p;
5415
5416                   p->balance = 0;
5417                   r->balance = 0;
5418
5419                   s = p->parent;
5420                   p->parent = r;
5421                   r->parent = s;
5422                   if (s)
5423                     {
5424                       if (s->left == p)
5425                         s->left = r;
5426                       else
5427                         s->right = r;
5428                     }
5429                   else
5430                     constructor_pending_elts = r;
5431                 }
5432               else
5433                 {
5434                   /* LR rotation.  */
5435                   struct init_node *t = r->right;
5436
5437                   r->right = t->left;
5438                   if (r->right)
5439                     r->right->parent = r;
5440                   t->left = r;
5441
5442                   p->left = t->right;
5443                   if (p->left)
5444                     p->left->parent = p;
5445                   t->right = p;
5446
5447                   p->balance = t->balance < 0;
5448                   r->balance = -(t->balance > 0);
5449                   t->balance = 0;
5450
5451                   s = p->parent;
5452                   p->parent = t;
5453                   r->parent = t;
5454                   t->parent = s;
5455                   if (s)
5456                     {
5457                       if (s->left == p)
5458                         s->left = t;
5459                       else
5460                         s->right = t;
5461                     }
5462                   else
5463                     constructor_pending_elts = t;
5464                 }
5465               break;
5466             }
5467           else
5468             {
5469               /* p->balance == +1; growth of left side balances the node.  */
5470               p->balance = 0;
5471               break;
5472             }
5473         }
5474       else /* r == p->right */
5475         {
5476           if (p->balance == 0)
5477             /* Growth propagation from right side.  */
5478             p->balance++;
5479           else if (p->balance > 0)
5480             {
5481               if (r->balance > 0)
5482                 {
5483                   /* R rotation.  */
5484                   p->right = r->left;
5485                   if (p->right)
5486                     p->right->parent = p;
5487                   r->left = p;
5488
5489                   p->balance = 0;
5490                   r->balance = 0;
5491
5492                   s = p->parent;
5493                   p->parent = r;
5494                   r->parent = s;
5495                   if (s)
5496                     {
5497                       if (s->left == p)
5498                         s->left = r;
5499                       else
5500                         s->right = r;
5501                     }
5502                   else
5503                     constructor_pending_elts = r;
5504                 }
5505               else /* r->balance == -1 */
5506                 {
5507                   /* RL rotation */
5508                   struct init_node *t = r->left;
5509
5510                   r->left = t->right;
5511                   if (r->left)
5512                     r->left->parent = r;
5513                   t->right = r;
5514
5515                   p->right = t->left;
5516                   if (p->right)
5517                     p->right->parent = p;
5518                   t->left = p;
5519
5520                   r->balance = (t->balance < 0);
5521                   p->balance = -(t->balance > 0);
5522                   t->balance = 0;
5523
5524                   s = p->parent;
5525                   p->parent = t;
5526                   r->parent = t;
5527                   t->parent = s;
5528                   if (s)
5529                     {
5530                       if (s->left == p)
5531                         s->left = t;
5532                       else
5533                         s->right = t;
5534                     }
5535                   else
5536                     constructor_pending_elts = t;
5537                 }
5538               break;
5539             }
5540           else
5541             {
5542               /* p->balance == -1; growth of right side balances the node.  */
5543               p->balance = 0;
5544               break;
5545             }
5546         }
5547
5548       r = p;
5549       p = p->parent;
5550     }
5551 }
5552
5553 /* Build AVL tree from a sorted chain.  */
5554
5555 static void
5556 set_nonincremental_init (void)
5557 {
5558   tree chain;
5559
5560   if (TREE_CODE (constructor_type) != RECORD_TYPE
5561       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5562     return;
5563
5564   for (chain = constructor_elements; chain; chain = TREE_CHAIN (chain))
5565     add_pending_init (TREE_PURPOSE (chain), TREE_VALUE (chain));
5566   constructor_elements = 0;
5567   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5568     {
5569       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5570       /* Skip any nameless bit fields at the beginning.  */
5571       while (constructor_unfilled_fields != 0
5572              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5573              && DECL_NAME (constructor_unfilled_fields) == 0)
5574         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5575
5576     }
5577   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5578     {
5579       if (TYPE_DOMAIN (constructor_type))
5580         constructor_unfilled_index
5581             = convert (bitsizetype,
5582                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5583       else
5584         constructor_unfilled_index = bitsize_zero_node;
5585     }
5586   constructor_incremental = 0;
5587 }
5588
5589 /* Build AVL tree from a string constant.  */
5590
5591 static void
5592 set_nonincremental_init_from_string (tree str)
5593 {
5594   tree value, purpose, type;
5595   HOST_WIDE_INT val[2];
5596   const char *p, *end;
5597   int byte, wchar_bytes, charwidth, bitpos;
5598
5599   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5600
5601   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5602       == TYPE_PRECISION (char_type_node))
5603     wchar_bytes = 1;
5604   else
5605     {
5606       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5607                   == TYPE_PRECISION (wchar_type_node));
5608       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5609     }
5610   charwidth = TYPE_PRECISION (char_type_node);
5611   type = TREE_TYPE (constructor_type);
5612   p = TREE_STRING_POINTER (str);
5613   end = p + TREE_STRING_LENGTH (str);
5614
5615   for (purpose = bitsize_zero_node;
5616        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5617        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5618     {
5619       if (wchar_bytes == 1)
5620         {
5621           val[1] = (unsigned char) *p++;
5622           val[0] = 0;
5623         }
5624       else
5625         {
5626           val[0] = 0;
5627           val[1] = 0;
5628           for (byte = 0; byte < wchar_bytes; byte++)
5629             {
5630               if (BYTES_BIG_ENDIAN)
5631                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5632               else
5633                 bitpos = byte * charwidth;
5634               val[bitpos < HOST_BITS_PER_WIDE_INT]
5635                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5636                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5637             }
5638         }
5639
5640       if (!TYPE_UNSIGNED (type))
5641         {
5642           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5643           if (bitpos < HOST_BITS_PER_WIDE_INT)
5644             {
5645               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5646                 {
5647                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5648                   val[0] = -1;
5649                 }
5650             }
5651           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5652             {
5653               if (val[1] < 0)
5654                 val[0] = -1;
5655             }
5656           else if (val[0] & (((HOST_WIDE_INT) 1)
5657                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5658             val[0] |= ((HOST_WIDE_INT) -1)
5659                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5660         }
5661
5662       value = build_int_cst_wide (type, val[1], val[0]);
5663       add_pending_init (purpose, value);
5664     }
5665
5666   constructor_incremental = 0;
5667 }
5668
5669 /* Return value of FIELD in pending initializer or zero if the field was
5670    not initialized yet.  */
5671
5672 static tree
5673 find_init_member (tree field)
5674 {
5675   struct init_node *p;
5676
5677   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5678     {
5679       if (constructor_incremental
5680           && tree_int_cst_lt (field, constructor_unfilled_index))
5681         set_nonincremental_init ();
5682
5683       p = constructor_pending_elts;
5684       while (p)
5685         {
5686           if (tree_int_cst_lt (field, p->purpose))
5687             p = p->left;
5688           else if (tree_int_cst_lt (p->purpose, field))
5689             p = p->right;
5690           else
5691             return p->value;
5692         }
5693     }
5694   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5695     {
5696       tree bitpos = bit_position (field);
5697
5698       if (constructor_incremental
5699           && (!constructor_unfilled_fields
5700               || tree_int_cst_lt (bitpos,
5701                                   bit_position (constructor_unfilled_fields))))
5702         set_nonincremental_init ();
5703
5704       p = constructor_pending_elts;
5705       while (p)
5706         {
5707           if (field == p->purpose)
5708             return p->value;
5709           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5710             p = p->left;
5711           else
5712             p = p->right;
5713         }
5714     }
5715   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5716     {
5717       if (constructor_elements
5718           && TREE_PURPOSE (constructor_elements) == field)
5719         return TREE_VALUE (constructor_elements);
5720     }
5721   return 0;
5722 }
5723
5724 /* "Output" the next constructor element.
5725    At top level, really output it to assembler code now.
5726    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5727    TYPE is the data type that the containing data type wants here.
5728    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5729    If VALUE is a string constant, STRICT_STRING is true if it is
5730    unparenthesized or we should not warn here for it being parenthesized.
5731    For other types of VALUE, STRICT_STRING is not used.
5732
5733    PENDING if non-nil means output pending elements that belong
5734    right after this element.  (PENDING is normally 1;
5735    it is 0 while outputting pending elements, to avoid recursion.)  */
5736
5737 static void
5738 output_init_element (tree value, bool strict_string, tree type, tree field,
5739                      int pending)
5740 {
5741   if (type == error_mark_node || value == error_mark_node)
5742     {
5743       constructor_erroneous = 1;
5744       return;
5745     }
5746   if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
5747       || (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5748           && !(TREE_CODE (value) == STRING_CST
5749                && TREE_CODE (type) == ARRAY_TYPE
5750                && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5751           && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5752                          TYPE_MAIN_VARIANT (type))))
5753     value = default_conversion (value);
5754
5755   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5756       && require_constant_value && !flag_isoc99 && pending)
5757     {
5758       /* As an extension, allow initializing objects with static storage
5759          duration with compound literals (which are then treated just as
5760          the brace enclosed list they contain).  */
5761       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5762       value = DECL_INITIAL (decl);
5763     }
5764
5765   if (value == error_mark_node)
5766     constructor_erroneous = 1;
5767   else if (!TREE_CONSTANT (value))
5768     constructor_constant = 0;
5769   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
5770            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5771                 || TREE_CODE (constructor_type) == UNION_TYPE)
5772                && DECL_C_BIT_FIELD (field)
5773                && TREE_CODE (value) != INTEGER_CST))
5774     constructor_simple = 0;
5775
5776   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
5777     {
5778       if (require_constant_value)
5779         {
5780           error_init ("initializer element is not constant");
5781           value = error_mark_node;
5782         }
5783       else if (require_constant_elements)
5784         pedwarn ("initializer element is not computable at load time");
5785     }
5786
5787   /* If this field is empty (and not at the end of structure),
5788      don't do anything other than checking the initializer.  */
5789   if (field
5790       && (TREE_TYPE (field) == error_mark_node
5791           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5792               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5793               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5794                   || TREE_CHAIN (field)))))
5795     return;
5796
5797   value = digest_init (type, value, strict_string, require_constant_value);
5798   if (value == error_mark_node)
5799     {
5800       constructor_erroneous = 1;
5801       return;
5802     }
5803
5804   /* If this element doesn't come next in sequence,
5805      put it on constructor_pending_elts.  */
5806   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5807       && (!constructor_incremental
5808           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5809     {
5810       if (constructor_incremental
5811           && tree_int_cst_lt (field, constructor_unfilled_index))
5812         set_nonincremental_init ();
5813
5814       add_pending_init (field, value);
5815       return;
5816     }
5817   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5818            && (!constructor_incremental
5819                || field != constructor_unfilled_fields))
5820     {
5821       /* We do this for records but not for unions.  In a union,
5822          no matter which field is specified, it can be initialized
5823          right away since it starts at the beginning of the union.  */
5824       if (constructor_incremental)
5825         {
5826           if (!constructor_unfilled_fields)
5827             set_nonincremental_init ();
5828           else
5829             {
5830               tree bitpos, unfillpos;
5831
5832               bitpos = bit_position (field);
5833               unfillpos = bit_position (constructor_unfilled_fields);
5834
5835               if (tree_int_cst_lt (bitpos, unfillpos))
5836                 set_nonincremental_init ();
5837             }
5838         }
5839
5840       add_pending_init (field, value);
5841       return;
5842     }
5843   else if (TREE_CODE (constructor_type) == UNION_TYPE
5844            && constructor_elements)
5845     {
5846       if (TREE_SIDE_EFFECTS (TREE_VALUE (constructor_elements)))
5847         warning_init ("initialized field with side-effects overwritten");
5848
5849       /* We can have just one union field set.  */
5850       constructor_elements = 0;
5851     }
5852
5853   /* Otherwise, output this element either to
5854      constructor_elements or to the assembler file.  */
5855
5856   if (field && TREE_CODE (field) == INTEGER_CST)
5857     field = copy_node (field);
5858   constructor_elements
5859     = tree_cons (field, value, constructor_elements);
5860
5861   /* Advance the variable that indicates sequential elements output.  */
5862   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5863     constructor_unfilled_index
5864       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5865                     bitsize_one_node);
5866   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5867     {
5868       constructor_unfilled_fields
5869         = TREE_CHAIN (constructor_unfilled_fields);
5870
5871       /* Skip any nameless bit fields.  */
5872       while (constructor_unfilled_fields != 0
5873              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5874              && DECL_NAME (constructor_unfilled_fields) == 0)
5875         constructor_unfilled_fields =
5876           TREE_CHAIN (constructor_unfilled_fields);
5877     }
5878   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5879     constructor_unfilled_fields = 0;
5880
5881   /* Now output any pending elements which have become next.  */
5882   if (pending)
5883     output_pending_init_elements (0);
5884 }
5885
5886 /* Output any pending elements which have become next.
5887    As we output elements, constructor_unfilled_{fields,index}
5888    advances, which may cause other elements to become next;
5889    if so, they too are output.
5890
5891    If ALL is 0, we return when there are
5892    no more pending elements to output now.
5893
5894    If ALL is 1, we output space as necessary so that
5895    we can output all the pending elements.  */
5896
5897 static void
5898 output_pending_init_elements (int all)
5899 {
5900   struct init_node *elt = constructor_pending_elts;
5901   tree next;
5902
5903  retry:
5904
5905   /* Look through the whole pending tree.
5906      If we find an element that should be output now,
5907      output it.  Otherwise, set NEXT to the element
5908      that comes first among those still pending.  */
5909
5910   next = 0;
5911   while (elt)
5912     {
5913       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5914         {
5915           if (tree_int_cst_equal (elt->purpose,
5916                                   constructor_unfilled_index))
5917             output_init_element (elt->value, true,
5918                                  TREE_TYPE (constructor_type),
5919                                  constructor_unfilled_index, 0);
5920           else if (tree_int_cst_lt (constructor_unfilled_index,
5921                                     elt->purpose))
5922             {
5923               /* Advance to the next smaller node.  */
5924               if (elt->left)
5925                 elt = elt->left;
5926               else
5927                 {
5928                   /* We have reached the smallest node bigger than the
5929                      current unfilled index.  Fill the space first.  */
5930                   next = elt->purpose;
5931                   break;
5932                 }
5933             }
5934           else
5935             {
5936               /* Advance to the next bigger node.  */
5937               if (elt->right)
5938                 elt = elt->right;
5939               else
5940                 {
5941                   /* We have reached the biggest node in a subtree.  Find
5942                      the parent of it, which is the next bigger node.  */
5943                   while (elt->parent && elt->parent->right == elt)
5944                     elt = elt->parent;
5945                   elt = elt->parent;
5946                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
5947                                               elt->purpose))
5948                     {
5949                       next = elt->purpose;
5950                       break;
5951                     }
5952                 }
5953             }
5954         }
5955       else if (TREE_CODE (constructor_type) == RECORD_TYPE
5956                || TREE_CODE (constructor_type) == UNION_TYPE)
5957         {
5958           tree ctor_unfilled_bitpos, elt_bitpos;
5959
5960           /* If the current record is complete we are done.  */
5961           if (constructor_unfilled_fields == 0)
5962             break;
5963
5964           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
5965           elt_bitpos = bit_position (elt->purpose);
5966           /* We can't compare fields here because there might be empty
5967              fields in between.  */
5968           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
5969             {
5970               constructor_unfilled_fields = elt->purpose;
5971               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
5972                                    elt->purpose, 0);
5973             }
5974           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
5975             {
5976               /* Advance to the next smaller node.  */
5977               if (elt->left)
5978                 elt = elt->left;
5979               else
5980                 {
5981                   /* We have reached the smallest node bigger than the
5982                      current unfilled field.  Fill the space first.  */
5983                   next = elt->purpose;
5984                   break;
5985                 }
5986             }
5987           else
5988             {
5989               /* Advance to the next bigger node.  */
5990               if (elt->right)
5991                 elt = elt->right;
5992               else
5993                 {
5994                   /* We have reached the biggest node in a subtree.  Find
5995                      the parent of it, which is the next bigger node.  */
5996                   while (elt->parent && elt->parent->right == elt)
5997                     elt = elt->parent;
5998                   elt = elt->parent;
5999                   if (elt
6000                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6001                                            bit_position (elt->purpose))))
6002                     {
6003                       next = elt->purpose;
6004                       break;
6005                     }
6006                 }
6007             }
6008         }
6009     }
6010
6011   /* Ordinarily return, but not if we want to output all
6012      and there are elements left.  */
6013   if (!(all && next != 0))
6014     return;
6015
6016   /* If it's not incremental, just skip over the gap, so that after
6017      jumping to retry we will output the next successive element.  */
6018   if (TREE_CODE (constructor_type) == RECORD_TYPE
6019       || TREE_CODE (constructor_type) == UNION_TYPE)
6020     constructor_unfilled_fields = next;
6021   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6022     constructor_unfilled_index = next;
6023
6024   /* ELT now points to the node in the pending tree with the next
6025      initializer to output.  */
6026   goto retry;
6027 }
6028 \f
6029 /* Add one non-braced element to the current constructor level.
6030    This adjusts the current position within the constructor's type.
6031    This may also start or terminate implicit levels
6032    to handle a partly-braced initializer.
6033
6034    Once this has found the correct level for the new element,
6035    it calls output_init_element.  */
6036
6037 void
6038 process_init_element (struct c_expr value)
6039 {
6040   tree orig_value = value.value;
6041   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6042   bool strict_string = value.original_code == STRING_CST;
6043
6044   designator_depth = 0;
6045   designator_errorneous = 0;
6046
6047   /* Handle superfluous braces around string cst as in
6048      char x[] = {"foo"}; */
6049   if (string_flag
6050       && constructor_type
6051       && TREE_CODE (constructor_type) == ARRAY_TYPE
6052       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6053       && integer_zerop (constructor_unfilled_index))
6054     {
6055       if (constructor_stack->replacement_value.value)
6056         error_init ("excess elements in char array initializer");
6057       constructor_stack->replacement_value = value;
6058       return;
6059     }
6060
6061   if (constructor_stack->replacement_value.value != 0)
6062     {
6063       error_init ("excess elements in struct initializer");
6064       return;
6065     }
6066
6067   /* Ignore elements of a brace group if it is entirely superfluous
6068      and has already been diagnosed.  */
6069   if (constructor_type == 0)
6070     return;
6071
6072   /* If we've exhausted any levels that didn't have braces,
6073      pop them now.  */
6074   while (constructor_stack->implicit)
6075     {
6076       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6077            || TREE_CODE (constructor_type) == UNION_TYPE)
6078           && constructor_fields == 0)
6079         process_init_element (pop_init_level (1));
6080       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6081                && (constructor_max_index == 0
6082                    || tree_int_cst_lt (constructor_max_index,
6083                                        constructor_index)))
6084         process_init_element (pop_init_level (1));
6085       else
6086         break;
6087     }
6088
6089   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6090   if (constructor_range_stack)
6091     {
6092       /* If value is a compound literal and we'll be just using its
6093          content, don't put it into a SAVE_EXPR.  */
6094       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6095           || !require_constant_value
6096           || flag_isoc99)
6097         value.value = save_expr (value.value);
6098     }
6099
6100   while (1)
6101     {
6102       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6103         {
6104           tree fieldtype;
6105           enum tree_code fieldcode;
6106
6107           if (constructor_fields == 0)
6108             {
6109               pedwarn_init ("excess elements in struct initializer");
6110               break;
6111             }
6112
6113           fieldtype = TREE_TYPE (constructor_fields);
6114           if (fieldtype != error_mark_node)
6115             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6116           fieldcode = TREE_CODE (fieldtype);
6117
6118           /* Error for non-static initialization of a flexible array member.  */
6119           if (fieldcode == ARRAY_TYPE
6120               && !require_constant_value
6121               && TYPE_SIZE (fieldtype) == NULL_TREE
6122               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6123             {
6124               error_init ("non-static initialization of a flexible array member");
6125               break;
6126             }
6127
6128           /* Accept a string constant to initialize a subarray.  */
6129           if (value.value != 0
6130               && fieldcode == ARRAY_TYPE
6131               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6132               && string_flag)
6133             value.value = orig_value;
6134           /* Otherwise, if we have come to a subaggregate,
6135              and we don't have an element of its type, push into it.  */
6136           else if (value.value != 0
6137                    && value.value != error_mark_node
6138                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6139                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6140                        || fieldcode == UNION_TYPE))
6141             {
6142               push_init_level (1);
6143               continue;
6144             }
6145
6146           if (value.value)
6147             {
6148               push_member_name (constructor_fields);
6149               output_init_element (value.value, strict_string,
6150                                    fieldtype, constructor_fields, 1);
6151               RESTORE_SPELLING_DEPTH (constructor_depth);
6152             }
6153           else
6154             /* Do the bookkeeping for an element that was
6155                directly output as a constructor.  */
6156             {
6157               /* For a record, keep track of end position of last field.  */
6158               if (DECL_SIZE (constructor_fields))
6159                 constructor_bit_index
6160                   = size_binop (PLUS_EXPR,
6161                                 bit_position (constructor_fields),
6162                                 DECL_SIZE (constructor_fields));
6163
6164               /* If the current field was the first one not yet written out,
6165                  it isn't now, so update.  */
6166               if (constructor_unfilled_fields == constructor_fields)
6167                 {
6168                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6169                   /* Skip any nameless bit fields.  */
6170                   while (constructor_unfilled_fields != 0
6171                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6172                          && DECL_NAME (constructor_unfilled_fields) == 0)
6173                     constructor_unfilled_fields =
6174                       TREE_CHAIN (constructor_unfilled_fields);
6175                 }
6176             }
6177
6178           constructor_fields = TREE_CHAIN (constructor_fields);
6179           /* Skip any nameless bit fields at the beginning.  */
6180           while (constructor_fields != 0
6181                  && DECL_C_BIT_FIELD (constructor_fields)
6182                  && DECL_NAME (constructor_fields) == 0)
6183             constructor_fields = TREE_CHAIN (constructor_fields);
6184         }
6185       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6186         {
6187           tree fieldtype;
6188           enum tree_code fieldcode;
6189
6190           if (constructor_fields == 0)
6191             {
6192               pedwarn_init ("excess elements in union initializer");
6193               break;
6194             }
6195
6196           fieldtype = TREE_TYPE (constructor_fields);
6197           if (fieldtype != error_mark_node)
6198             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6199           fieldcode = TREE_CODE (fieldtype);
6200
6201           /* Warn that traditional C rejects initialization of unions.
6202              We skip the warning if the value is zero.  This is done
6203              under the assumption that the zero initializer in user
6204              code appears conditioned on e.g. __STDC__ to avoid
6205              "missing initializer" warnings and relies on default
6206              initialization to zero in the traditional C case.
6207              We also skip the warning if the initializer is designated,
6208              again on the assumption that this must be conditional on
6209              __STDC__ anyway (and we've already complained about the
6210              member-designator already).  */
6211           if (warn_traditional && !in_system_header && !constructor_designated
6212               && !(value.value && (integer_zerop (value.value)
6213                                    || real_zerop (value.value))))
6214             warning (0, "traditional C rejects initialization of unions");
6215
6216           /* Accept a string constant to initialize a subarray.  */
6217           if (value.value != 0
6218               && fieldcode == ARRAY_TYPE
6219               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6220               && string_flag)
6221             value.value = orig_value;
6222           /* Otherwise, if we have come to a subaggregate,
6223              and we don't have an element of its type, push into it.  */
6224           else if (value.value != 0
6225                    && value.value != error_mark_node
6226                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6227                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6228                        || fieldcode == UNION_TYPE))
6229             {
6230               push_init_level (1);
6231               continue;
6232             }
6233
6234           if (value.value)
6235             {
6236               push_member_name (constructor_fields);
6237               output_init_element (value.value, strict_string,
6238                                    fieldtype, constructor_fields, 1);
6239               RESTORE_SPELLING_DEPTH (constructor_depth);
6240             }
6241           else
6242             /* Do the bookkeeping for an element that was
6243                directly output as a constructor.  */
6244             {
6245               constructor_bit_index = DECL_SIZE (constructor_fields);
6246               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6247             }
6248
6249           constructor_fields = 0;
6250         }
6251       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6252         {
6253           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6254           enum tree_code eltcode = TREE_CODE (elttype);
6255
6256           /* Accept a string constant to initialize a subarray.  */
6257           if (value.value != 0
6258               && eltcode == ARRAY_TYPE
6259               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6260               && string_flag)
6261             value.value = orig_value;
6262           /* Otherwise, if we have come to a subaggregate,
6263              and we don't have an element of its type, push into it.  */
6264           else if (value.value != 0
6265                    && value.value != error_mark_node
6266                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6267                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6268                        || eltcode == UNION_TYPE))
6269             {
6270               push_init_level (1);
6271               continue;
6272             }
6273
6274           if (constructor_max_index != 0
6275               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6276                   || integer_all_onesp (constructor_max_index)))
6277             {
6278               pedwarn_init ("excess elements in array initializer");
6279               break;
6280             }
6281
6282           /* Now output the actual element.  */
6283           if (value.value)
6284             {
6285               push_array_bounds (tree_low_cst (constructor_index, 0));
6286               output_init_element (value.value, strict_string,
6287                                    elttype, constructor_index, 1);
6288               RESTORE_SPELLING_DEPTH (constructor_depth);
6289             }
6290
6291           constructor_index
6292             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6293
6294           if (!value.value)
6295             /* If we are doing the bookkeeping for an element that was
6296                directly output as a constructor, we must update
6297                constructor_unfilled_index.  */
6298             constructor_unfilled_index = constructor_index;
6299         }
6300       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6301         {
6302           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6303
6304          /* Do a basic check of initializer size.  Note that vectors
6305             always have a fixed size derived from their type.  */
6306           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6307             {
6308               pedwarn_init ("excess elements in vector initializer");
6309               break;
6310             }
6311
6312           /* Now output the actual element.  */
6313           if (value.value)
6314             output_init_element (value.value, strict_string,
6315                                  elttype, constructor_index, 1);
6316
6317           constructor_index
6318             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6319
6320           if (!value.value)
6321             /* If we are doing the bookkeeping for an element that was
6322                directly output as a constructor, we must update
6323                constructor_unfilled_index.  */
6324             constructor_unfilled_index = constructor_index;
6325         }
6326
6327       /* Handle the sole element allowed in a braced initializer
6328          for a scalar variable.  */
6329       else if (constructor_type != error_mark_node
6330                && constructor_fields == 0)
6331         {
6332           pedwarn_init ("excess elements in scalar initializer");
6333           break;
6334         }
6335       else
6336         {
6337           if (value.value)
6338             output_init_element (value.value, strict_string,
6339                                  constructor_type, NULL_TREE, 1);
6340           constructor_fields = 0;
6341         }
6342
6343       /* Handle range initializers either at this level or anywhere higher
6344          in the designator stack.  */
6345       if (constructor_range_stack)
6346         {
6347           struct constructor_range_stack *p, *range_stack;
6348           int finish = 0;
6349
6350           range_stack = constructor_range_stack;
6351           constructor_range_stack = 0;
6352           while (constructor_stack != range_stack->stack)
6353             {
6354               gcc_assert (constructor_stack->implicit);
6355               process_init_element (pop_init_level (1));
6356             }
6357           for (p = range_stack;
6358                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6359                p = p->prev)
6360             {
6361               gcc_assert (constructor_stack->implicit);
6362               process_init_element (pop_init_level (1));
6363             }
6364
6365           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6366           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6367             finish = 1;
6368
6369           while (1)
6370             {
6371               constructor_index = p->index;
6372               constructor_fields = p->fields;
6373               if (finish && p->range_end && p->index == p->range_start)
6374                 {
6375                   finish = 0;
6376                   p->prev = 0;
6377                 }
6378               p = p->next;
6379               if (!p)
6380                 break;
6381               push_init_level (2);
6382               p->stack = constructor_stack;
6383               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6384                 p->index = p->range_start;
6385             }
6386
6387           if (!finish)
6388             constructor_range_stack = range_stack;
6389           continue;
6390         }
6391
6392       break;
6393     }
6394
6395   constructor_range_stack = 0;
6396 }
6397 \f
6398 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6399    (guaranteed to be 'volatile' or null) and ARGS (represented using
6400    an ASM_EXPR node).  */
6401 tree
6402 build_asm_stmt (tree cv_qualifier, tree args)
6403 {
6404   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6405     ASM_VOLATILE_P (args) = 1;
6406   return add_stmt (args);
6407 }
6408
6409 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6410    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6411    SIMPLE indicates whether there was anything at all after the
6412    string in the asm expression -- asm("blah") and asm("blah" : )
6413    are subtly different.  We use a ASM_EXPR node to represent this.  */
6414 tree
6415 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6416                 bool simple)
6417 {
6418   tree tail;
6419   tree args;
6420   int i;
6421   const char *constraint;
6422   const char **oconstraints;
6423   bool allows_mem, allows_reg, is_inout;
6424   int ninputs, noutputs;
6425
6426   ninputs = list_length (inputs);
6427   noutputs = list_length (outputs);
6428   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6429
6430   string = resolve_asm_operand_names (string, outputs, inputs);
6431
6432   /* Remove output conversions that change the type but not the mode.  */
6433   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6434     {
6435       tree output = TREE_VALUE (tail);
6436
6437       /* ??? Really, this should not be here.  Users should be using a
6438          proper lvalue, dammit.  But there's a long history of using casts
6439          in the output operands.  In cases like longlong.h, this becomes a
6440          primitive form of typechecking -- if the cast can be removed, then
6441          the output operand had a type of the proper width; otherwise we'll
6442          get an error.  Gross, but ...  */
6443       STRIP_NOPS (output);
6444
6445       if (!lvalue_or_else (output, lv_asm))
6446         output = error_mark_node;
6447
6448       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6449       oconstraints[i] = constraint;
6450
6451       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6452                                    &allows_mem, &allows_reg, &is_inout))
6453         {
6454           /* If the operand is going to end up in memory,
6455              mark it addressable.  */
6456           if (!allows_reg && !c_mark_addressable (output))
6457             output = error_mark_node;
6458         }
6459       else
6460         output = error_mark_node;
6461
6462       TREE_VALUE (tail) = output;
6463     }
6464
6465   /* Perform default conversions on array and function inputs.
6466      Don't do this for other types as it would screw up operands
6467      expected to be in memory.  */
6468   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6469     {
6470       tree input;
6471
6472       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6473       input = TREE_VALUE (tail);
6474
6475       input = default_function_array_conversion (input);
6476
6477       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6478                                   oconstraints, &allows_mem, &allows_reg))
6479         {
6480           /* If the operand is going to end up in memory,
6481              mark it addressable.  */
6482           if (!allows_reg && allows_mem)
6483             {
6484               /* Strip the nops as we allow this case.  FIXME, this really
6485                  should be rejected or made deprecated.  */
6486               STRIP_NOPS (input);
6487               if (!c_mark_addressable (input))
6488                 input = error_mark_node;
6489           }
6490         }
6491       else
6492         input = error_mark_node;
6493
6494       TREE_VALUE (tail) = input;
6495     }
6496
6497   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6498
6499   /* Simple asm statements are treated as volatile.  */
6500   if (simple)
6501     {
6502       ASM_VOLATILE_P (args) = 1;
6503       ASM_INPUT_P (args) = 1;
6504     }
6505
6506   return args;
6507 }
6508 \f
6509 /* Generate a goto statement to LABEL.  */
6510
6511 tree
6512 c_finish_goto_label (tree label)
6513 {
6514   tree decl = lookup_label (label);
6515   if (!decl)
6516     return NULL_TREE;
6517
6518   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6519     {
6520       error ("jump into statement expression");
6521       return NULL_TREE;
6522     }
6523
6524   if (C_DECL_UNJUMPABLE_VM (decl))
6525     {
6526       error ("jump into scope of identifier with variably modified type");
6527       return NULL_TREE;
6528     }
6529
6530   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6531     {
6532       /* No jump from outside this statement expression context, so
6533          record that there is a jump from within this context.  */
6534       struct c_label_list *nlist;
6535       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6536       nlist->next = label_context_stack_se->labels_used;
6537       nlist->label = decl;
6538       label_context_stack_se->labels_used = nlist;
6539     }
6540
6541   if (!C_DECL_UNDEFINABLE_VM (decl))
6542     {
6543       /* No jump from outside this context context of identifiers with
6544          variably modified type, so record that there is a jump from
6545          within this context.  */
6546       struct c_label_list *nlist;
6547       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6548       nlist->next = label_context_stack_vm->labels_used;
6549       nlist->label = decl;
6550       label_context_stack_vm->labels_used = nlist;
6551     }
6552
6553   TREE_USED (decl) = 1;
6554   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6555 }
6556
6557 /* Generate a computed goto statement to EXPR.  */
6558
6559 tree
6560 c_finish_goto_ptr (tree expr)
6561 {
6562   if (pedantic)
6563     pedwarn ("ISO C forbids %<goto *expr;%>");
6564   expr = convert (ptr_type_node, expr);
6565   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6566 }
6567
6568 /* Generate a C `return' statement.  RETVAL is the expression for what
6569    to return, or a null pointer for `return;' with no value.  */
6570
6571 tree
6572 c_finish_return (tree retval)
6573 {
6574   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6575
6576   if (TREE_THIS_VOLATILE (current_function_decl))
6577     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6578
6579   if (!retval)
6580     {
6581       current_function_returns_null = 1;
6582       if ((warn_return_type || flag_isoc99)
6583           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6584         pedwarn_c99 ("%<return%> with no value, in "
6585                      "function returning non-void");
6586     }
6587   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6588     {
6589       current_function_returns_null = 1;
6590       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6591         pedwarn ("%<return%> with a value, in function returning void");
6592     }
6593   else
6594     {
6595       tree t = convert_for_assignment (valtype, retval, ic_return,
6596                                        NULL_TREE, NULL_TREE, 0);
6597       tree res = DECL_RESULT (current_function_decl);
6598       tree inner;
6599
6600       current_function_returns_value = 1;
6601       if (t == error_mark_node)
6602         return NULL_TREE;
6603
6604       inner = t = convert (TREE_TYPE (res), t);
6605
6606       /* Strip any conversions, additions, and subtractions, and see if
6607          we are returning the address of a local variable.  Warn if so.  */
6608       while (1)
6609         {
6610           switch (TREE_CODE (inner))
6611             {
6612             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6613             case PLUS_EXPR:
6614               inner = TREE_OPERAND (inner, 0);
6615               continue;
6616
6617             case MINUS_EXPR:
6618               /* If the second operand of the MINUS_EXPR has a pointer
6619                  type (or is converted from it), this may be valid, so
6620                  don't give a warning.  */
6621               {
6622                 tree op1 = TREE_OPERAND (inner, 1);
6623
6624                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6625                        && (TREE_CODE (op1) == NOP_EXPR
6626                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6627                            || TREE_CODE (op1) == CONVERT_EXPR))
6628                   op1 = TREE_OPERAND (op1, 0);
6629
6630                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6631                   break;
6632
6633                 inner = TREE_OPERAND (inner, 0);
6634                 continue;
6635               }
6636
6637             case ADDR_EXPR:
6638               inner = TREE_OPERAND (inner, 0);
6639
6640               while (REFERENCE_CLASS_P (inner)
6641                      && TREE_CODE (inner) != INDIRECT_REF)
6642                 inner = TREE_OPERAND (inner, 0);
6643
6644               if (DECL_P (inner)
6645                   && !DECL_EXTERNAL (inner)
6646                   && !TREE_STATIC (inner)
6647                   && DECL_CONTEXT (inner) == current_function_decl)
6648                 warning (0, "function returns address of local variable");
6649               break;
6650
6651             default:
6652               break;
6653             }
6654
6655           break;
6656         }
6657
6658       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6659     }
6660
6661   return add_stmt (build_stmt (RETURN_EXPR, retval));
6662 }
6663 \f
6664 struct c_switch {
6665   /* The SWITCH_EXPR being built.  */
6666   tree switch_expr;
6667
6668   /* The original type of the testing expression, i.e. before the
6669      default conversion is applied.  */
6670   tree orig_type;
6671
6672   /* A splay-tree mapping the low element of a case range to the high
6673      element, or NULL_TREE if there is no high element.  Used to
6674      determine whether or not a new case label duplicates an old case
6675      label.  We need a tree, rather than simply a hash table, because
6676      of the GNU case range extension.  */
6677   splay_tree cases;
6678
6679   /* Number of nested statement expressions within this switch
6680      statement; if nonzero, case and default labels may not
6681      appear.  */
6682   unsigned int blocked_stmt_expr;
6683
6684   /* Scope of outermost declarations of identifiers with variably
6685      modified type within this switch statement; if nonzero, case and
6686      default labels may not appear.  */
6687   unsigned int blocked_vm;
6688
6689   /* The next node on the stack.  */
6690   struct c_switch *next;
6691 };
6692
6693 /* A stack of the currently active switch statements.  The innermost
6694    switch statement is on the top of the stack.  There is no need to
6695    mark the stack for garbage collection because it is only active
6696    during the processing of the body of a function, and we never
6697    collect at that point.  */
6698
6699 struct c_switch *c_switch_stack;
6700
6701 /* Start a C switch statement, testing expression EXP.  Return the new
6702    SWITCH_EXPR.  */
6703
6704 tree
6705 c_start_case (tree exp)
6706 {
6707   enum tree_code code;
6708   tree type, orig_type = error_mark_node;
6709   struct c_switch *cs;
6710
6711   if (exp != error_mark_node)
6712     {
6713       code = TREE_CODE (TREE_TYPE (exp));
6714       orig_type = TREE_TYPE (exp);
6715
6716       if (!INTEGRAL_TYPE_P (orig_type)
6717           && code != ERROR_MARK)
6718         {
6719           error ("switch quantity not an integer");
6720           exp = integer_zero_node;
6721           orig_type = error_mark_node;
6722         }
6723       else
6724         {
6725           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6726
6727           if (warn_traditional && !in_system_header
6728               && (type == long_integer_type_node
6729                   || type == long_unsigned_type_node))
6730             warning (0, "%<long%> switch expression not converted to "
6731                      "%<int%> in ISO C");
6732
6733           exp = default_conversion (exp);
6734           type = TREE_TYPE (exp);
6735         }
6736     }
6737
6738   /* Add this new SWITCH_EXPR to the stack.  */
6739   cs = XNEW (struct c_switch);
6740   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6741   cs->orig_type = orig_type;
6742   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6743   cs->blocked_stmt_expr = 0;
6744   cs->blocked_vm = 0;
6745   cs->next = c_switch_stack;
6746   c_switch_stack = cs;
6747
6748   return add_stmt (cs->switch_expr);
6749 }
6750
6751 /* Process a case label.  */
6752
6753 tree
6754 do_case (tree low_value, tree high_value)
6755 {
6756   tree label = NULL_TREE;
6757
6758   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
6759       && !c_switch_stack->blocked_vm)
6760     {
6761       label = c_add_case_label (c_switch_stack->cases,
6762                                 SWITCH_COND (c_switch_stack->switch_expr),
6763                                 c_switch_stack->orig_type,
6764                                 low_value, high_value);
6765       if (label == error_mark_node)
6766         label = NULL_TREE;
6767     }
6768   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
6769     {
6770       if (low_value)
6771         error ("case label in statement expression not containing "
6772                "enclosing switch statement");
6773       else
6774         error ("%<default%> label in statement expression not containing "
6775                "enclosing switch statement");
6776     }
6777   else if (c_switch_stack && c_switch_stack->blocked_vm)
6778     {
6779       if (low_value)
6780         error ("case label in scope of identifier with variably modified "
6781                "type not containing enclosing switch statement");
6782       else
6783         error ("%<default%> label in scope of identifier with variably "
6784                "modified type not containing enclosing switch statement");
6785     }
6786   else if (low_value)
6787     error ("case label not within a switch statement");
6788   else
6789     error ("%<default%> label not within a switch statement");
6790
6791   return label;
6792 }
6793
6794 /* Finish the switch statement.  */
6795
6796 void
6797 c_finish_case (tree body)
6798 {
6799   struct c_switch *cs = c_switch_stack;
6800   location_t switch_location;
6801
6802   SWITCH_BODY (cs->switch_expr) = body;
6803
6804   /* We must not be within a statement expression nested in the switch
6805      at this point; we might, however, be within the scope of an
6806      identifier with variably modified type nested in the switch.  */
6807   gcc_assert (!cs->blocked_stmt_expr);
6808
6809   /* Emit warnings as needed.  */
6810   if (EXPR_HAS_LOCATION (cs->switch_expr))
6811     switch_location = EXPR_LOCATION (cs->switch_expr);
6812   else
6813     switch_location = input_location;
6814   c_do_switch_warnings (cs->cases, switch_location,
6815                         TREE_TYPE (cs->switch_expr),
6816                         SWITCH_COND (cs->switch_expr));
6817
6818   /* Pop the stack.  */
6819   c_switch_stack = cs->next;
6820   splay_tree_delete (cs->cases);
6821   XDELETE (cs);
6822 }
6823 \f
6824 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6825    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6826    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6827    statement, and was not surrounded with parenthesis.  */
6828
6829 void
6830 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6831                   tree else_block, bool nested_if)
6832 {
6833   tree stmt;
6834
6835   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6836   if (warn_parentheses && nested_if && else_block == NULL)
6837     {
6838       tree inner_if = then_block;
6839
6840       /* We know from the grammar productions that there is an IF nested
6841          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6842          it might not be exactly THEN_BLOCK, but should be the last
6843          non-container statement within.  */
6844       while (1)
6845         switch (TREE_CODE (inner_if))
6846           {
6847           case COND_EXPR:
6848             goto found;
6849           case BIND_EXPR:
6850             inner_if = BIND_EXPR_BODY (inner_if);
6851             break;
6852           case STATEMENT_LIST:
6853             inner_if = expr_last (then_block);
6854             break;
6855           case TRY_FINALLY_EXPR:
6856           case TRY_CATCH_EXPR:
6857             inner_if = TREE_OPERAND (inner_if, 0);
6858             break;
6859           default:
6860             gcc_unreachable ();
6861           }
6862     found:
6863
6864       if (COND_EXPR_ELSE (inner_if))
6865          warning (0, "%Hsuggest explicit braces to avoid ambiguous %<else%>",
6866                   &if_locus);
6867     }
6868
6869   /* Diagnose ";" via the special empty statement node that we create.  */
6870   if (extra_warnings)
6871     {
6872       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
6873         {
6874           if (!else_block)
6875             warning (0, "%Hempty body in an if-statement",
6876                      EXPR_LOCUS (then_block));
6877           then_block = alloc_stmt_list ();
6878         }
6879       if (else_block
6880           && TREE_CODE (else_block) == NOP_EXPR
6881           && !TREE_TYPE (else_block))
6882         {
6883           warning (0, "%Hempty body in an else-statement",
6884                    EXPR_LOCUS (else_block));
6885           else_block = alloc_stmt_list ();
6886         }
6887     }
6888
6889   stmt = build3 (COND_EXPR, NULL_TREE, cond, then_block, else_block);
6890   SET_EXPR_LOCATION (stmt, if_locus);
6891   add_stmt (stmt);
6892 }
6893
6894 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
6895    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
6896    is false for DO loops.  INCR is the FOR increment expression.  BODY is
6897    the statement controlled by the loop.  BLAB is the break label.  CLAB is
6898    the continue label.  Everything is allowed to be NULL.  */
6899
6900 void
6901 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
6902                tree blab, tree clab, bool cond_is_first)
6903 {
6904   tree entry = NULL, exit = NULL, t;
6905
6906   /* If the condition is zero don't generate a loop construct.  */
6907   if (cond && integer_zerop (cond))
6908     {
6909       if (cond_is_first)
6910         {
6911           t = build_and_jump (&blab);
6912           SET_EXPR_LOCATION (t, start_locus);
6913           add_stmt (t);
6914         }
6915     }
6916   else
6917     {
6918       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6919
6920       /* If we have an exit condition, then we build an IF with gotos either
6921          out of the loop, or to the top of it.  If there's no exit condition,
6922          then we just build a jump back to the top.  */
6923       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
6924
6925       if (cond && !integer_nonzerop (cond))
6926         {
6927           /* Canonicalize the loop condition to the end.  This means
6928              generating a branch to the loop condition.  Reuse the
6929              continue label, if possible.  */
6930           if (cond_is_first)
6931             {
6932               if (incr || !clab)
6933                 {
6934                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6935                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
6936                 }
6937               else
6938                 t = build1 (GOTO_EXPR, void_type_node, clab);
6939               SET_EXPR_LOCATION (t, start_locus);
6940               add_stmt (t);
6941             }
6942
6943           t = build_and_jump (&blab);
6944           exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
6945           exit = fold (exit);
6946           if (cond_is_first)
6947             SET_EXPR_LOCATION (exit, start_locus);
6948           else
6949             SET_EXPR_LOCATION (exit, input_location);
6950         }
6951
6952       add_stmt (top);
6953     }
6954
6955   if (body)
6956     add_stmt (body);
6957   if (clab)
6958     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
6959   if (incr)
6960     add_stmt (incr);
6961   if (entry)
6962     add_stmt (entry);
6963   if (exit)
6964     add_stmt (exit);
6965   if (blab)
6966     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
6967 }
6968
6969 tree
6970 c_finish_bc_stmt (tree *label_p, bool is_break)
6971 {
6972   bool skip;
6973   tree label = *label_p;
6974
6975   /* In switch statements break is sometimes stylistically used after
6976      a return statement.  This can lead to spurious warnings about
6977      control reaching the end of a non-void function when it is
6978      inlined.  Note that we are calling block_may_fallthru with
6979      language specific tree nodes; this works because
6980      block_may_fallthru returns true when given something it does not
6981      understand.  */
6982   skip = !block_may_fallthru (cur_stmt_list);
6983
6984   if (!label)
6985     {
6986       if (!skip)
6987         *label_p = label = create_artificial_label ();
6988     }
6989   else if (TREE_CODE (label) != LABEL_DECL)
6990     {
6991       if (is_break)
6992         error ("break statement not within loop or switch");
6993       else
6994         error ("continue statement not within a loop");
6995       return NULL_TREE;
6996     }
6997
6998   if (skip)
6999     return NULL_TREE;
7000
7001   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7002 }
7003
7004 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7005
7006 static void
7007 emit_side_effect_warnings (tree expr)
7008 {
7009   if (expr == error_mark_node)
7010     ;
7011   else if (!TREE_SIDE_EFFECTS (expr))
7012     {
7013       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7014         warning (0, "%Hstatement with no effect",
7015                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7016     }
7017   else if (warn_unused_value)
7018     warn_if_unused_value (expr, input_location);
7019 }
7020
7021 /* Process an expression as if it were a complete statement.  Emit
7022    diagnostics, but do not call ADD_STMT.  */
7023
7024 tree
7025 c_process_expr_stmt (tree expr)
7026 {
7027   if (!expr)
7028     return NULL_TREE;
7029
7030   /* Do default conversion if safe and possibly important,
7031      in case within ({...}).  */
7032   if ((TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE
7033        && (flag_isoc99 || lvalue_p (expr)))
7034       || TREE_CODE (TREE_TYPE (expr)) == FUNCTION_TYPE)
7035     expr = default_conversion (expr);
7036
7037   if (warn_sequence_point)
7038     verify_sequence_points (expr);
7039
7040   if (TREE_TYPE (expr) != error_mark_node
7041       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7042       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7043     error ("expression statement has incomplete type");
7044
7045   /* If we're not processing a statement expression, warn about unused values.
7046      Warnings for statement expressions will be emitted later, once we figure
7047      out which is the result.  */
7048   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7049       && (extra_warnings || warn_unused_value))
7050     emit_side_effect_warnings (expr);
7051
7052   /* If the expression is not of a type to which we cannot assign a line
7053      number, wrap the thing in a no-op NOP_EXPR.  */
7054   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7055     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7056
7057   if (EXPR_P (expr))
7058     SET_EXPR_LOCATION (expr, input_location);
7059
7060   return expr;
7061 }
7062
7063 /* Emit an expression as a statement.  */
7064
7065 tree
7066 c_finish_expr_stmt (tree expr)
7067 {
7068   if (expr)
7069     return add_stmt (c_process_expr_stmt (expr));
7070   else
7071     return NULL;
7072 }
7073
7074 /* Do the opposite and emit a statement as an expression.  To begin,
7075    create a new binding level and return it.  */
7076
7077 tree
7078 c_begin_stmt_expr (void)
7079 {
7080   tree ret;
7081   struct c_label_context_se *nstack;
7082   struct c_label_list *glist;
7083
7084   /* We must force a BLOCK for this level so that, if it is not expanded
7085      later, there is a way to turn off the entire subtree of blocks that
7086      are contained in it.  */
7087   keep_next_level ();
7088   ret = c_begin_compound_stmt (true);
7089   if (c_switch_stack)
7090     {
7091       c_switch_stack->blocked_stmt_expr++;
7092       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7093     }
7094   for (glist = label_context_stack_se->labels_used;
7095        glist != NULL;
7096        glist = glist->next)
7097     {
7098       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7099     }
7100   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7101   nstack->labels_def = NULL;
7102   nstack->labels_used = NULL;
7103   nstack->next = label_context_stack_se;
7104   label_context_stack_se = nstack;
7105
7106   /* Mark the current statement list as belonging to a statement list.  */
7107   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7108
7109   return ret;
7110 }
7111
7112 tree
7113 c_finish_stmt_expr (tree body)
7114 {
7115   tree last, type, tmp, val;
7116   tree *last_p;
7117   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7118
7119   body = c_end_compound_stmt (body, true);
7120   if (c_switch_stack)
7121     {
7122       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7123       c_switch_stack->blocked_stmt_expr--;
7124     }
7125   /* It is no longer possible to jump to labels defined within this
7126      statement expression.  */
7127   for (dlist = label_context_stack_se->labels_def;
7128        dlist != NULL;
7129        dlist = dlist->next)
7130     {
7131       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7132     }
7133   /* It is again possible to define labels with a goto just outside
7134      this statement expression.  */
7135   for (glist = label_context_stack_se->next->labels_used;
7136        glist != NULL;
7137        glist = glist->next)
7138     {
7139       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7140       glist_prev = glist;
7141     }
7142   if (glist_prev != NULL)
7143     glist_prev->next = label_context_stack_se->labels_used;
7144   else
7145     label_context_stack_se->next->labels_used
7146       = label_context_stack_se->labels_used;
7147   label_context_stack_se = label_context_stack_se->next;
7148
7149   /* Locate the last statement in BODY.  See c_end_compound_stmt
7150      about always returning a BIND_EXPR.  */
7151   last_p = &BIND_EXPR_BODY (body);
7152   last = BIND_EXPR_BODY (body);
7153
7154  continue_searching:
7155   if (TREE_CODE (last) == STATEMENT_LIST)
7156     {
7157       tree_stmt_iterator i;
7158
7159       /* This can happen with degenerate cases like ({ }).  No value.  */
7160       if (!TREE_SIDE_EFFECTS (last))
7161         return body;
7162
7163       /* If we're supposed to generate side effects warnings, process
7164          all of the statements except the last.  */
7165       if (extra_warnings || warn_unused_value)
7166         {
7167           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7168             emit_side_effect_warnings (tsi_stmt (i));
7169         }
7170       else
7171         i = tsi_last (last);
7172       last_p = tsi_stmt_ptr (i);
7173       last = *last_p;
7174     }
7175
7176   /* If the end of the list is exception related, then the list was split
7177      by a call to push_cleanup.  Continue searching.  */
7178   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7179       || TREE_CODE (last) == TRY_CATCH_EXPR)
7180     {
7181       last_p = &TREE_OPERAND (last, 0);
7182       last = *last_p;
7183       goto continue_searching;
7184     }
7185
7186   /* In the case that the BIND_EXPR is not necessary, return the
7187      expression out from inside it.  */
7188   if (last == error_mark_node
7189       || (last == BIND_EXPR_BODY (body)
7190           && BIND_EXPR_VARS (body) == NULL))
7191     return last;
7192
7193   /* Extract the type of said expression.  */
7194   type = TREE_TYPE (last);
7195
7196   /* If we're not returning a value at all, then the BIND_EXPR that
7197      we already have is a fine expression to return.  */
7198   if (!type || VOID_TYPE_P (type))
7199     return body;
7200
7201   /* Now that we've located the expression containing the value, it seems
7202      silly to make voidify_wrapper_expr repeat the process.  Create a
7203      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7204   tmp = create_tmp_var_raw (type, NULL);
7205
7206   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7207      tree_expr_nonnegative_p giving up immediately.  */
7208   val = last;
7209   if (TREE_CODE (val) == NOP_EXPR
7210       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7211     val = TREE_OPERAND (val, 0);
7212
7213   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7214   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7215
7216   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7217 }
7218
7219 /* Begin the scope of an identifier of variably modified type, scope
7220    number SCOPE.  Jumping from outside this scope to inside it is not
7221    permitted.  */
7222
7223 void
7224 c_begin_vm_scope (unsigned int scope)
7225 {
7226   struct c_label_context_vm *nstack;
7227   struct c_label_list *glist;
7228
7229   gcc_assert (scope > 0);
7230   if (c_switch_stack && !c_switch_stack->blocked_vm)
7231     c_switch_stack->blocked_vm = scope;
7232   for (glist = label_context_stack_vm->labels_used;
7233        glist != NULL;
7234        glist = glist->next)
7235     {
7236       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7237     }
7238   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7239   nstack->labels_def = NULL;
7240   nstack->labels_used = NULL;
7241   nstack->scope = scope;
7242   nstack->next = label_context_stack_vm;
7243   label_context_stack_vm = nstack;
7244 }
7245
7246 /* End a scope which may contain identifiers of variably modified
7247    type, scope number SCOPE.  */
7248
7249 void
7250 c_end_vm_scope (unsigned int scope)
7251 {
7252   if (label_context_stack_vm == NULL)
7253     return;
7254   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7255     c_switch_stack->blocked_vm = 0;
7256   /* We may have a number of nested scopes of identifiers with
7257      variably modified type, all at this depth.  Pop each in turn.  */
7258   while (label_context_stack_vm->scope == scope)
7259     {
7260       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7261
7262       /* It is no longer possible to jump to labels defined within this
7263          scope.  */
7264       for (dlist = label_context_stack_vm->labels_def;
7265            dlist != NULL;
7266            dlist = dlist->next)
7267         {
7268           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7269         }
7270       /* It is again possible to define labels with a goto just outside
7271          this scope.  */
7272       for (glist = label_context_stack_vm->next->labels_used;
7273            glist != NULL;
7274            glist = glist->next)
7275         {
7276           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7277           glist_prev = glist;
7278         }
7279       if (glist_prev != NULL)
7280         glist_prev->next = label_context_stack_vm->labels_used;
7281       else
7282         label_context_stack_vm->next->labels_used
7283           = label_context_stack_vm->labels_used;
7284       label_context_stack_vm = label_context_stack_vm->next;
7285     }
7286 }
7287 \f
7288 /* Begin and end compound statements.  This is as simple as pushing
7289    and popping new statement lists from the tree.  */
7290
7291 tree
7292 c_begin_compound_stmt (bool do_scope)
7293 {
7294   tree stmt = push_stmt_list ();
7295   if (do_scope)
7296     push_scope ();
7297   return stmt;
7298 }
7299
7300 tree
7301 c_end_compound_stmt (tree stmt, bool do_scope)
7302 {
7303   tree block = NULL;
7304
7305   if (do_scope)
7306     {
7307       if (c_dialect_objc ())
7308         objc_clear_super_receiver ();
7309       block = pop_scope ();
7310     }
7311
7312   stmt = pop_stmt_list (stmt);
7313   stmt = c_build_bind_expr (block, stmt);
7314
7315   /* If this compound statement is nested immediately inside a statement
7316      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7317      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7318      STATEMENT_LISTs merge, and thus we can lose track of what statement
7319      was really last.  */
7320   if (cur_stmt_list
7321       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7322       && TREE_CODE (stmt) != BIND_EXPR)
7323     {
7324       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7325       TREE_SIDE_EFFECTS (stmt) = 1;
7326     }
7327
7328   return stmt;
7329 }
7330
7331 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7332    when the current scope is exited.  EH_ONLY is true when this is not
7333    meant to apply to normal control flow transfer.  */
7334
7335 void
7336 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7337 {
7338   enum tree_code code;
7339   tree stmt, list;
7340   bool stmt_expr;
7341
7342   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7343   stmt = build_stmt (code, NULL, cleanup);
7344   add_stmt (stmt);
7345   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7346   list = push_stmt_list ();
7347   TREE_OPERAND (stmt, 0) = list;
7348   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7349 }
7350 \f
7351 /* Build a binary-operation expression without default conversions.
7352    CODE is the kind of expression to build.
7353    This function differs from `build' in several ways:
7354    the data type of the result is computed and recorded in it,
7355    warnings are generated if arg data types are invalid,
7356    special handling for addition and subtraction of pointers is known,
7357    and some optimization is done (operations on narrow ints
7358    are done in the narrower type when that gives the same result).
7359    Constant folding is also done before the result is returned.
7360
7361    Note that the operands will never have enumeral types, or function
7362    or array types, because either they will have the default conversions
7363    performed or they have both just been converted to some other type in which
7364    the arithmetic is to be done.  */
7365
7366 tree
7367 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7368                  int convert_p)
7369 {
7370   tree type0, type1;
7371   enum tree_code code0, code1;
7372   tree op0, op1;
7373
7374   /* Expression code to give to the expression when it is built.
7375      Normally this is CODE, which is what the caller asked for,
7376      but in some special cases we change it.  */
7377   enum tree_code resultcode = code;
7378
7379   /* Data type in which the computation is to be performed.
7380      In the simplest cases this is the common type of the arguments.  */
7381   tree result_type = NULL;
7382
7383   /* Nonzero means operands have already been type-converted
7384      in whatever way is necessary.
7385      Zero means they need to be converted to RESULT_TYPE.  */
7386   int converted = 0;
7387
7388   /* Nonzero means create the expression with this type, rather than
7389      RESULT_TYPE.  */
7390   tree build_type = 0;
7391
7392   /* Nonzero means after finally constructing the expression
7393      convert it to this type.  */
7394   tree final_type = 0;
7395
7396   /* Nonzero if this is an operation like MIN or MAX which can
7397      safely be computed in short if both args are promoted shorts.
7398      Also implies COMMON.
7399      -1 indicates a bitwise operation; this makes a difference
7400      in the exact conditions for when it is safe to do the operation
7401      in a narrower mode.  */
7402   int shorten = 0;
7403
7404   /* Nonzero if this is a comparison operation;
7405      if both args are promoted shorts, compare the original shorts.
7406      Also implies COMMON.  */
7407   int short_compare = 0;
7408
7409   /* Nonzero if this is a right-shift operation, which can be computed on the
7410      original short and then promoted if the operand is a promoted short.  */
7411   int short_shift = 0;
7412
7413   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7414   int common = 0;
7415
7416   if (convert_p)
7417     {
7418       op0 = default_conversion (orig_op0);
7419       op1 = default_conversion (orig_op1);
7420     }
7421   else
7422     {
7423       op0 = orig_op0;
7424       op1 = orig_op1;
7425     }
7426
7427   type0 = TREE_TYPE (op0);
7428   type1 = TREE_TYPE (op1);
7429
7430   /* The expression codes of the data types of the arguments tell us
7431      whether the arguments are integers, floating, pointers, etc.  */
7432   code0 = TREE_CODE (type0);
7433   code1 = TREE_CODE (type1);
7434
7435   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7436   STRIP_TYPE_NOPS (op0);
7437   STRIP_TYPE_NOPS (op1);
7438
7439   /* If an error was already reported for one of the arguments,
7440      avoid reporting another error.  */
7441
7442   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7443     return error_mark_node;
7444
7445   switch (code)
7446     {
7447     case PLUS_EXPR:
7448       /* Handle the pointer + int case.  */
7449       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7450         return pointer_int_sum (PLUS_EXPR, op0, op1);
7451       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7452         return pointer_int_sum (PLUS_EXPR, op1, op0);
7453       else
7454         common = 1;
7455       break;
7456
7457     case MINUS_EXPR:
7458       /* Subtraction of two similar pointers.
7459          We must subtract them as integers, then divide by object size.  */
7460       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7461           && comp_target_types (type0, type1, 1))
7462         return pointer_diff (op0, op1);
7463       /* Handle pointer minus int.  Just like pointer plus int.  */
7464       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7465         return pointer_int_sum (MINUS_EXPR, op0, op1);
7466       else
7467         common = 1;
7468       break;
7469
7470     case MULT_EXPR:
7471       common = 1;
7472       break;
7473
7474     case TRUNC_DIV_EXPR:
7475     case CEIL_DIV_EXPR:
7476     case FLOOR_DIV_EXPR:
7477     case ROUND_DIV_EXPR:
7478     case EXACT_DIV_EXPR:
7479       /* Floating point division by zero is a legitimate way to obtain
7480          infinities and NaNs.  */
7481       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
7482         warning (0, "division by zero");
7483
7484       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7485            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7486           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7487               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7488         {
7489           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7490             code0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7491           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7492             code1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7493
7494           if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
7495             resultcode = RDIV_EXPR;
7496           else
7497             /* Although it would be tempting to shorten always here, that
7498                loses on some targets, since the modulo instruction is
7499                undefined if the quotient can't be represented in the
7500                computation mode.  We shorten only if unsigned or if
7501                dividing by something we know != -1.  */
7502             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7503                        || (TREE_CODE (op1) == INTEGER_CST
7504                            && !integer_all_onesp (op1)));
7505           common = 1;
7506         }
7507       break;
7508
7509     case BIT_AND_EXPR:
7510     case BIT_IOR_EXPR:
7511     case BIT_XOR_EXPR:
7512       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7513         shorten = -1;
7514       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7515         common = 1;
7516       break;
7517
7518     case TRUNC_MOD_EXPR:
7519     case FLOOR_MOD_EXPR:
7520       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
7521         warning (0, "division by zero");
7522
7523       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7524         {
7525           /* Although it would be tempting to shorten always here, that loses
7526              on some targets, since the modulo instruction is undefined if the
7527              quotient can't be represented in the computation mode.  We shorten
7528              only if unsigned or if dividing by something we know != -1.  */
7529           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7530                      || (TREE_CODE (op1) == INTEGER_CST
7531                          && !integer_all_onesp (op1)));
7532           common = 1;
7533         }
7534       break;
7535
7536     case TRUTH_ANDIF_EXPR:
7537     case TRUTH_ORIF_EXPR:
7538     case TRUTH_AND_EXPR:
7539     case TRUTH_OR_EXPR:
7540     case TRUTH_XOR_EXPR:
7541       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7542            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7543           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7544               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7545         {
7546           /* Result of these operations is always an int,
7547              but that does not mean the operands should be
7548              converted to ints!  */
7549           result_type = integer_type_node;
7550           op0 = c_common_truthvalue_conversion (op0);
7551           op1 = c_common_truthvalue_conversion (op1);
7552           converted = 1;
7553         }
7554       break;
7555
7556       /* Shift operations: result has same type as first operand;
7557          always convert second operand to int.
7558          Also set SHORT_SHIFT if shifting rightward.  */
7559
7560     case RSHIFT_EXPR:
7561       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7562         {
7563           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7564             {
7565               if (tree_int_cst_sgn (op1) < 0)
7566                 warning (0, "right shift count is negative");
7567               else
7568                 {
7569                   if (!integer_zerop (op1))
7570                     short_shift = 1;
7571
7572                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7573                     warning (0, "right shift count >= width of type");
7574                 }
7575             }
7576
7577           /* Use the type of the value to be shifted.  */
7578           result_type = type0;
7579           /* Convert the shift-count to an integer, regardless of size
7580              of value being shifted.  */
7581           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7582             op1 = convert (integer_type_node, op1);
7583           /* Avoid converting op1 to result_type later.  */
7584           converted = 1;
7585         }
7586       break;
7587
7588     case LSHIFT_EXPR:
7589       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7590         {
7591           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7592             {
7593               if (tree_int_cst_sgn (op1) < 0)
7594                 warning (0, "left shift count is negative");
7595
7596               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7597                 warning (0, "left shift count >= width of type");
7598             }
7599
7600           /* Use the type of the value to be shifted.  */
7601           result_type = type0;
7602           /* Convert the shift-count to an integer, regardless of size
7603              of value being shifted.  */
7604           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7605             op1 = convert (integer_type_node, op1);
7606           /* Avoid converting op1 to result_type later.  */
7607           converted = 1;
7608         }
7609       break;
7610
7611     case EQ_EXPR:
7612     case NE_EXPR:
7613       if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
7614         warning (0, "comparing floating point with == or != is unsafe");
7615       /* Result of comparison is always int,
7616          but don't convert the args to int!  */
7617       build_type = integer_type_node;
7618       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7619            || code0 == COMPLEX_TYPE)
7620           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7621               || code1 == COMPLEX_TYPE))
7622         short_compare = 1;
7623       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7624         {
7625           tree tt0 = TREE_TYPE (type0);
7626           tree tt1 = TREE_TYPE (type1);
7627           /* Anything compares with void *.  void * compares with anything.
7628              Otherwise, the targets must be compatible
7629              and both must be object or both incomplete.  */
7630           if (comp_target_types (type0, type1, 1))
7631             result_type = common_pointer_type (type0, type1);
7632           else if (VOID_TYPE_P (tt0))
7633             {
7634               /* op0 != orig_op0 detects the case of something
7635                  whose value is 0 but which isn't a valid null ptr const.  */
7636               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7637                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7638                 pedwarn ("ISO C forbids comparison of %<void *%>"
7639                          " with function pointer");
7640             }
7641           else if (VOID_TYPE_P (tt1))
7642             {
7643               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7644                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7645                 pedwarn ("ISO C forbids comparison of %<void *%>"
7646                          " with function pointer");
7647             }
7648           else
7649             pedwarn ("comparison of distinct pointer types lacks a cast");
7650
7651           if (result_type == NULL_TREE)
7652             result_type = ptr_type_node;
7653         }
7654       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7655                && integer_zerop (op1))
7656         result_type = type0;
7657       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7658                && integer_zerop (op0))
7659         result_type = type1;
7660       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7661         {
7662           result_type = type0;
7663           pedwarn ("comparison between pointer and integer");
7664         }
7665       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7666         {
7667           result_type = type1;
7668           pedwarn ("comparison between pointer and integer");
7669         }
7670       break;
7671
7672     case LE_EXPR:
7673     case GE_EXPR:
7674     case LT_EXPR:
7675     case GT_EXPR:
7676       build_type = integer_type_node;
7677       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7678           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7679         short_compare = 1;
7680       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7681         {
7682           if (comp_target_types (type0, type1, 1))
7683             {
7684               result_type = common_pointer_type (type0, type1);
7685               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7686                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7687                 pedwarn ("comparison of complete and incomplete pointers");
7688               else if (pedantic
7689                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7690                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7691             }
7692           else
7693             {
7694               result_type = ptr_type_node;
7695               pedwarn ("comparison of distinct pointer types lacks a cast");
7696             }
7697         }
7698       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7699                && integer_zerop (op1))
7700         {
7701           result_type = type0;
7702           if (pedantic || extra_warnings)
7703             pedwarn ("ordered comparison of pointer with integer zero");
7704         }
7705       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7706                && integer_zerop (op0))
7707         {
7708           result_type = type1;
7709           if (pedantic)
7710             pedwarn ("ordered comparison of pointer with integer zero");
7711         }
7712       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7713         {
7714           result_type = type0;
7715           pedwarn ("comparison between pointer and integer");
7716         }
7717       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7718         {
7719           result_type = type1;
7720           pedwarn ("comparison between pointer and integer");
7721         }
7722       break;
7723
7724     default:
7725       gcc_unreachable ();
7726     }
7727
7728   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7729     return error_mark_node;
7730
7731   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7732        || code0 == VECTOR_TYPE)
7733       &&
7734       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7735        || code1 == VECTOR_TYPE))
7736     {
7737       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7738
7739       if (shorten || common || short_compare)
7740         result_type = c_common_type (type0, type1);
7741
7742       /* For certain operations (which identify themselves by shorten != 0)
7743          if both args were extended from the same smaller type,
7744          do the arithmetic in that type and then extend.
7745
7746          shorten !=0 and !=1 indicates a bitwise operation.
7747          For them, this optimization is safe only if
7748          both args are zero-extended or both are sign-extended.
7749          Otherwise, we might change the result.
7750          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7751          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7752
7753       if (shorten && none_complex)
7754         {
7755           int unsigned0, unsigned1;
7756           tree arg0 = get_narrower (op0, &unsigned0);
7757           tree arg1 = get_narrower (op1, &unsigned1);
7758           /* UNS is 1 if the operation to be done is an unsigned one.  */
7759           int uns = TYPE_UNSIGNED (result_type);
7760           tree type;
7761
7762           final_type = result_type;
7763
7764           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7765              but it *requires* conversion to FINAL_TYPE.  */
7766
7767           if ((TYPE_PRECISION (TREE_TYPE (op0))
7768                == TYPE_PRECISION (TREE_TYPE (arg0)))
7769               && TREE_TYPE (op0) != final_type)
7770             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7771           if ((TYPE_PRECISION (TREE_TYPE (op1))
7772                == TYPE_PRECISION (TREE_TYPE (arg1)))
7773               && TREE_TYPE (op1) != final_type)
7774             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7775
7776           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7777
7778           /* For bitwise operations, signedness of nominal type
7779              does not matter.  Consider only how operands were extended.  */
7780           if (shorten == -1)
7781             uns = unsigned0;
7782
7783           /* Note that in all three cases below we refrain from optimizing
7784              an unsigned operation on sign-extended args.
7785              That would not be valid.  */
7786
7787           /* Both args variable: if both extended in same way
7788              from same width, do it in that width.
7789              Do it unsigned if args were zero-extended.  */
7790           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7791                < TYPE_PRECISION (result_type))
7792               && (TYPE_PRECISION (TREE_TYPE (arg1))
7793                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7794               && unsigned0 == unsigned1
7795               && (unsigned0 || !uns))
7796             result_type
7797               = c_common_signed_or_unsigned_type
7798               (unsigned0, c_common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7799           else if (TREE_CODE (arg0) == INTEGER_CST
7800                    && (unsigned1 || !uns)
7801                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7802                        < TYPE_PRECISION (result_type))
7803                    && (type
7804                        = c_common_signed_or_unsigned_type (unsigned1,
7805                                                            TREE_TYPE (arg1)),
7806                        int_fits_type_p (arg0, type)))
7807             result_type = type;
7808           else if (TREE_CODE (arg1) == INTEGER_CST
7809                    && (unsigned0 || !uns)
7810                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7811                        < TYPE_PRECISION (result_type))
7812                    && (type
7813                        = c_common_signed_or_unsigned_type (unsigned0,
7814                                                            TREE_TYPE (arg0)),
7815                        int_fits_type_p (arg1, type)))
7816             result_type = type;
7817         }
7818
7819       /* Shifts can be shortened if shifting right.  */
7820
7821       if (short_shift)
7822         {
7823           int unsigned_arg;
7824           tree arg0 = get_narrower (op0, &unsigned_arg);
7825
7826           final_type = result_type;
7827
7828           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7829             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7830
7831           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7832               /* We can shorten only if the shift count is less than the
7833                  number of bits in the smaller type size.  */
7834               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7835               /* We cannot drop an unsigned shift after sign-extension.  */
7836               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7837             {
7838               /* Do an unsigned shift if the operand was zero-extended.  */
7839               result_type
7840                 = c_common_signed_or_unsigned_type (unsigned_arg,
7841                                                     TREE_TYPE (arg0));
7842               /* Convert value-to-be-shifted to that type.  */
7843               if (TREE_TYPE (op0) != result_type)
7844                 op0 = convert (result_type, op0);
7845               converted = 1;
7846             }
7847         }
7848
7849       /* Comparison operations are shortened too but differently.
7850          They identify themselves by setting short_compare = 1.  */
7851
7852       if (short_compare)
7853         {
7854           /* Don't write &op0, etc., because that would prevent op0
7855              from being kept in a register.
7856              Instead, make copies of the our local variables and
7857              pass the copies by reference, then copy them back afterward.  */
7858           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7859           enum tree_code xresultcode = resultcode;
7860           tree val
7861             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7862
7863           if (val != 0)
7864             return val;
7865
7866           op0 = xop0, op1 = xop1;
7867           converted = 1;
7868           resultcode = xresultcode;
7869
7870           if (warn_sign_compare && skip_evaluation == 0)
7871             {
7872               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
7873               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
7874               int unsignedp0, unsignedp1;
7875               tree primop0 = get_narrower (op0, &unsignedp0);
7876               tree primop1 = get_narrower (op1, &unsignedp1);
7877
7878               xop0 = orig_op0;
7879               xop1 = orig_op1;
7880               STRIP_TYPE_NOPS (xop0);
7881               STRIP_TYPE_NOPS (xop1);
7882
7883               /* Give warnings for comparisons between signed and unsigned
7884                  quantities that may fail.
7885
7886                  Do the checking based on the original operand trees, so that
7887                  casts will be considered, but default promotions won't be.
7888
7889                  Do not warn if the comparison is being done in a signed type,
7890                  since the signed type will only be chosen if it can represent
7891                  all the values of the unsigned type.  */
7892               if (!TYPE_UNSIGNED (result_type))
7893                 /* OK */;
7894               /* Do not warn if both operands are the same signedness.  */
7895               else if (op0_signed == op1_signed)
7896                 /* OK */;
7897               else
7898                 {
7899                   tree sop, uop;
7900
7901                   if (op0_signed)
7902                     sop = xop0, uop = xop1;
7903                   else
7904                     sop = xop1, uop = xop0;
7905
7906                   /* Do not warn if the signed quantity is an
7907                      unsuffixed integer literal (or some static
7908                      constant expression involving such literals or a
7909                      conditional expression involving such literals)
7910                      and it is non-negative.  */
7911                   if (tree_expr_nonnegative_p (sop))
7912                     /* OK */;
7913                   /* Do not warn if the comparison is an equality operation,
7914                      the unsigned quantity is an integral constant, and it
7915                      would fit in the result if the result were signed.  */
7916                   else if (TREE_CODE (uop) == INTEGER_CST
7917                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
7918                            && int_fits_type_p
7919                            (uop, c_common_signed_type (result_type)))
7920                     /* OK */;
7921                   /* Do not warn if the unsigned quantity is an enumeration
7922                      constant and its maximum value would fit in the result
7923                      if the result were signed.  */
7924                   else if (TREE_CODE (uop) == INTEGER_CST
7925                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
7926                            && int_fits_type_p
7927                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
7928                             c_common_signed_type (result_type)))
7929                     /* OK */;
7930                   else
7931                     warning (0, "comparison between signed and unsigned");
7932                 }
7933
7934               /* Warn if two unsigned values are being compared in a size
7935                  larger than their original size, and one (and only one) is the
7936                  result of a `~' operator.  This comparison will always fail.
7937
7938                  Also warn if one operand is a constant, and the constant
7939                  does not have all bits set that are set in the ~ operand
7940                  when it is extended.  */
7941
7942               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
7943                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
7944                 {
7945                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
7946                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
7947                                             &unsignedp0);
7948                   else
7949                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
7950                                             &unsignedp1);
7951
7952                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
7953                     {
7954                       tree primop;
7955                       HOST_WIDE_INT constant, mask;
7956                       int unsignedp, bits;
7957
7958                       if (host_integerp (primop0, 0))
7959                         {
7960                           primop = primop1;
7961                           unsignedp = unsignedp1;
7962                           constant = tree_low_cst (primop0, 0);
7963                         }
7964                       else
7965                         {
7966                           primop = primop0;
7967                           unsignedp = unsignedp0;
7968                           constant = tree_low_cst (primop1, 0);
7969                         }
7970
7971                       bits = TYPE_PRECISION (TREE_TYPE (primop));
7972                       if (bits < TYPE_PRECISION (result_type)
7973                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
7974                         {
7975                           mask = (~(HOST_WIDE_INT) 0) << bits;
7976                           if ((mask & constant) != mask)
7977                             warning (0, "comparison of promoted ~unsigned with constant");
7978                         }
7979                     }
7980                   else if (unsignedp0 && unsignedp1
7981                            && (TYPE_PRECISION (TREE_TYPE (primop0))
7982                                < TYPE_PRECISION (result_type))
7983                            && (TYPE_PRECISION (TREE_TYPE (primop1))
7984                                < TYPE_PRECISION (result_type)))
7985                     warning (0, "comparison of promoted ~unsigned with unsigned");
7986                 }
7987             }
7988         }
7989     }
7990
7991   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
7992      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
7993      Then the expression will be built.
7994      It will be given type FINAL_TYPE if that is nonzero;
7995      otherwise, it will be given type RESULT_TYPE.  */
7996
7997   if (!result_type)
7998     {
7999       binary_op_error (code);
8000       return error_mark_node;
8001     }
8002
8003   if (!converted)
8004     {
8005       if (TREE_TYPE (op0) != result_type)
8006         op0 = convert (result_type, op0);
8007       if (TREE_TYPE (op1) != result_type)
8008         op1 = convert (result_type, op1);
8009
8010       /* This can happen if one operand has a vector type, and the other
8011          has a different type.  */
8012       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8013         return error_mark_node;
8014     }
8015
8016   if (build_type == NULL_TREE)
8017     build_type = result_type;
8018
8019   {
8020     tree result = build2 (resultcode, build_type, op0, op1);
8021
8022     /* Treat expressions in initializers specially as they can't trap.  */
8023     result = require_constant_value ? fold_initializer (result)
8024                                     : fold (result);
8025
8026     if (final_type != 0)
8027       result = convert (final_type, result);
8028     return result;
8029   }
8030 }
8031
8032
8033 /* Convert EXPR to be a truth-value, validating its type for this
8034    purpose.  Passes EXPR to default_function_array_conversion.  */
8035
8036 tree
8037 c_objc_common_truthvalue_conversion (tree expr)
8038 {
8039   expr = default_function_array_conversion (expr);
8040   switch (TREE_CODE (TREE_TYPE (expr)))
8041     {
8042     case ARRAY_TYPE:
8043       error ("used array that cannot be converted to pointer where scalar is required");
8044       return error_mark_node;
8045
8046     case RECORD_TYPE:
8047       error ("used struct type value where scalar is required");
8048       return error_mark_node;
8049
8050     case UNION_TYPE:
8051       error ("used union type value where scalar is required");
8052       return error_mark_node;
8053
8054     default:
8055       break;
8056     }
8057
8058   /* ??? Should we also give an error for void and vectors rather than
8059      leaving those to give errors later?  */
8060   return c_common_truthvalue_conversion (expr);
8061 }