gcc/c-typeck.c

   1 /* Build expressions with type checking for C compiler.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "tree-gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static tree qualify_type (tree, tree);
  78 static int tagged_types_tu_compatible_p (tree, tree);
  79 static int comp_target_types (tree, tree);
  80 static int function_types_compatible_p (tree, tree);
  81 static int type_lists_compatible_p (tree, tree);
  82 static tree decl_constant_value_for_broken_optimization (tree);
  83 static tree lookup_field (tree, tree);
  84 static tree convert_arguments (tree, tree, tree, tree);
  85 static tree pointer_diff (tree, tree);
  86 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  87                                     int);
  88 static tree valid_compound_expr_initializer (tree, tree);
  89 static void push_string (const char *);
  90 static void push_member_name (tree);
  91 static void push_array_bounds (int);
  92 static int spelling_length (void);
  93 static char *print_spelling (char *);
  94 static void warning_init (const char *);
  95 static tree digest_init (tree, tree, bool, int);
  96 static void output_init_element (tree, bool, tree, tree, int);
  97 static void output_pending_init_elements (int);
  98 static int set_designator (int);
  99 static void push_range_stack (tree);
 100 static void add_pending_init (tree, tree);
 101 static void set_nonincremental_init (void);
 102 static void set_nonincremental_init_from_string (tree);
 103 static tree find_init_member (tree);
 104 static void readonly_error (tree, enum lvalue_use);
 105 static int lvalue_or_else (tree, enum lvalue_use);
 106 static int lvalue_p (tree);
 107 static void record_maybe_used_decl (tree);
 108 \f
 109 /* Do `exp = require_complete_type (exp);' to make sure exp
 110    does not have an incomplete type.  (That includes void types.)  */
 111
 112 tree
 113 require_complete_type (tree value)
 114 {
 115   tree type = TREE_TYPE (value);
 116
 117   if (value == error_mark_node || type == error_mark_node)
 118     return error_mark_node;
 119
 120   /* First, detect a valid value with a complete type.  */
 121   if (COMPLETE_TYPE_P (type))
 122     return value;
 123
 124   c_incomplete_type_error (value, type);
 125   return error_mark_node;
 126 }
 127
 128 /* Print an error message for invalid use of an incomplete type.
 129    VALUE is the expression that was used (or 0 if that isn't known)
 130    and TYPE is the type that was invalid.  */
 131
 132 void
 133 c_incomplete_type_error (tree value, tree type)
 134 {
 135   const char *type_code_string;
 136
 137   /* Avoid duplicate error message.  */
 138   if (TREE_CODE (type) == ERROR_MARK)
 139     return;
 140
 141   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 142                      || TREE_CODE (value) == PARM_DECL))
 143     error ("%qD has an incomplete type", value);
 144   else
 145     {
 146     retry:
 147       /* We must print an error message.  Be clever about what it says.  */
 148
 149       switch (TREE_CODE (type))
 150         {
 151         case RECORD_TYPE:
 152           type_code_string = "struct";
 153           break;
 154
 155         case UNION_TYPE:
 156           type_code_string = "union";
 157           break;
 158
 159         case ENUMERAL_TYPE:
 160           type_code_string = "enum";
 161           break;
 162
 163         case VOID_TYPE:
 164           error ("invalid use of void expression");
 165           return;
 166
 167         case ARRAY_TYPE:
 168           if (TYPE_DOMAIN (type))
 169             {
 170               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 171                 {
 172                   error ("invalid use of flexible array member");
 173                   return;
 174                 }
 175               type = TREE_TYPE (type);
 176               goto retry;
 177             }
 178           error ("invalid use of array with unspecified bounds");
 179           return;
 180
 181         default:
 182           gcc_unreachable ();
 183         }
 184
 185       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 186         error ("invalid use of undefined type %<%s %E%>",
 187                type_code_string, TYPE_NAME (type));
 188       else
 189         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 190         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 191     }
 192 }
 193
 194 /* Given a type, apply default promotions wrt unnamed function
 195    arguments and return the new type.  */
 196
 197 tree
 198 c_type_promotes_to (tree type)
 199 {
 200   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 201     return double_type_node;
 202
 203   if (c_promoting_integer_type_p (type))
 204     {
 205       /* Preserve unsignedness if not really getting any wider.  */
 206       if (TYPE_UNSIGNED (type)
 207           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 208         return unsigned_type_node;
 209       return integer_type_node;
 210     }
 211
 212   return type;
 213 }
 214
 215 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 216    as well as those of TYPE.  */
 217
 218 static tree
 219 qualify_type (tree type, tree like)
 220 {
 221   return c_build_qualified_type (type,
 222                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 223 }
 224 \f
 225 /* Return the composite type of two compatible types.
 226
 227    We assume that comptypes has already been done and returned
 228    nonzero; if that isn't so, this may crash.  In particular, we
 229    assume that qualifiers match.  */
 230
 231 tree
 232 composite_type (tree t1, tree t2)
 233 {
 234   enum tree_code code1;
 235   enum tree_code code2;
 236   tree attributes;
 237
 238   /* Save time if the two types are the same.  */
 239
 240   if (t1 == t2) return t1;
 241
 242   /* If one type is nonsense, use the other.  */
 243   if (t1 == error_mark_node)
 244     return t2;
 245   if (t2 == error_mark_node)
 246     return t1;
 247
 248   code1 = TREE_CODE (t1);
 249   code2 = TREE_CODE (t2);
 250
 251   /* Merge the attributes.  */
 252   attributes = targetm.merge_type_attributes (t1, t2);
 253
 254   /* If one is an enumerated type and the other is the compatible
 255      integer type, the composite type might be either of the two
 256      (DR#013 question 3).  For consistency, use the enumerated type as
 257      the composite type.  */
 258
 259   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 260     return t1;
 261   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 262     return t2;
 263
 264   gcc_assert (code1 == code2);
 265
 266   switch (code1)
 267     {
 268     case POINTER_TYPE:
 269       /* For two pointers, do this recursively on the target type.  */
 270       {
 271         tree pointed_to_1 = TREE_TYPE (t1);
 272         tree pointed_to_2 = TREE_TYPE (t2);
 273         tree target = composite_type (pointed_to_1, pointed_to_2);
 274         t1 = build_pointer_type (target);
 275         t1 = build_type_attribute_variant (t1, attributes);
 276         return qualify_type (t1, t2);
 277       }
 278
 279     case ARRAY_TYPE:
 280       {
 281         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 282         int quals;
 283         tree unqual_elt;
 284
 285         /* We should not have any type quals on arrays at all.  */
 286         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 287
 288         /* Save space: see if the result is identical to one of the args.  */
 289         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
 290           return build_type_attribute_variant (t1, attributes);
 291         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
 292           return build_type_attribute_variant (t2, attributes);
 293
 294         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 295           return build_type_attribute_variant (t1, attributes);
 296         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 297           return build_type_attribute_variant (t2, attributes);
 298
 299         /* Merge the element types, and have a size if either arg has
 300            one.  We may have qualifiers on the element types.  To set
 301            up TYPE_MAIN_VARIANT correctly, we need to form the
 302            composite of the unqualified types and add the qualifiers
 303            back at the end.  */
 304         quals = TYPE_QUALS (strip_array_types (elt));
 305         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 306         t1 = build_array_type (unqual_elt,
 307                                TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
 308         t1 = c_build_qualified_type (t1, quals);
 309         return build_type_attribute_variant (t1, attributes);
 310       }
 311
 312     case FUNCTION_TYPE:
 313       /* Function types: prefer the one that specified arg types.
 314          If both do, merge the arg types.  Also merge the return types.  */
 315       {
 316         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 317         tree p1 = TYPE_ARG_TYPES (t1);
 318         tree p2 = TYPE_ARG_TYPES (t2);
 319         int len;
 320         tree newargs, n;
 321         int i;
 322
 323         /* Save space: see if the result is identical to one of the args.  */
 324         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 325           return build_type_attribute_variant (t1, attributes);
 326         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 327           return build_type_attribute_variant (t2, attributes);
 328
 329         /* Simple way if one arg fails to specify argument types.  */
 330         if (TYPE_ARG_TYPES (t1) == 0)
 331          {
 332             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 333             t1 = build_type_attribute_variant (t1, attributes);
 334             return qualify_type (t1, t2);
 335          }
 336         if (TYPE_ARG_TYPES (t2) == 0)
 337          {
 338            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 339            t1 = build_type_attribute_variant (t1, attributes);
 340            return qualify_type (t1, t2);
 341          }
 342
 343         /* If both args specify argument types, we must merge the two
 344            lists, argument by argument.  */
 345         /* Tell global_bindings_p to return false so that variable_size
 346            doesn't die on VLAs in parameter types.  */
 347         c_override_global_bindings_to_false = true;
 348
 349         len = list_length (p1);
 350         newargs = 0;
 351
 352         for (i = 0; i < len; i++)
 353           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 354
 355         n = newargs;
 356
 357         for (; p1;
 358              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 359           {
 360             /* A null type means arg type is not specified.
 361                Take whatever the other function type has.  */
 362             if (TREE_VALUE (p1) == 0)
 363               {
 364                 TREE_VALUE (n) = TREE_VALUE (p2);
 365                 goto parm_done;
 366               }
 367             if (TREE_VALUE (p2) == 0)
 368               {
 369                 TREE_VALUE (n) = TREE_VALUE (p1);
 370                 goto parm_done;
 371               }
 372
 373             /* Given  wait (union {union wait *u; int *i} *)
 374                and  wait (union wait *),
 375                prefer  union wait *  as type of parm.  */
 376             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 377                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 378               {
 379                 tree memb;
 380                 tree mv2 = TREE_VALUE (p2);
 381                 if (mv2 && mv2 != error_mark_node
 382                     && TREE_CODE (mv2) != ARRAY_TYPE)
 383                   mv2 = TYPE_MAIN_VARIANT (mv2);
 384                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 385                      memb; memb = TREE_CHAIN (memb))
 386                   {
 387                     tree mv3 = TREE_TYPE (memb);
 388                     if (mv3 && mv3 != error_mark_node
 389                         && TREE_CODE (mv3) != ARRAY_TYPE)
 390                       mv3 = TYPE_MAIN_VARIANT (mv3);
 391                     if (comptypes (mv3, mv2))
 392                       {
 393                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 394                                                          TREE_VALUE (p2));
 395                         if (pedantic)
 396                           pedwarn ("function types not truly compatible in ISO C");
 397                         goto parm_done;
 398                       }
 399                   }
 400               }
 401             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 402                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 403               {
 404                 tree memb;
 405                 tree mv1 = TREE_VALUE (p1);
 406                 if (mv1 && mv1 != error_mark_node
 407                     && TREE_CODE (mv1) != ARRAY_TYPE)
 408                   mv1 = TYPE_MAIN_VARIANT (mv1);
 409                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 410                      memb; memb = TREE_CHAIN (memb))
 411                   {
 412                     tree mv3 = TREE_TYPE (memb);
 413                     if (mv3 && mv3 != error_mark_node
 414                         && TREE_CODE (mv3) != ARRAY_TYPE)
 415                       mv3 = TYPE_MAIN_VARIANT (mv3);
 416                     if (comptypes (mv3, mv1))
 417                       {
 418                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 419                                                          TREE_VALUE (p1));
 420                         if (pedantic)
 421                           pedwarn ("function types not truly compatible in ISO C");
 422                         goto parm_done;
 423                       }
 424                   }
 425               }
 426             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 427           parm_done: ;
 428           }
 429
 430         c_override_global_bindings_to_false = false;
 431         t1 = build_function_type (valtype, newargs);
 432         t1 = qualify_type (t1, t2);
 433         /* ... falls through ...  */
 434       }
 435
 436     default:
 437       return build_type_attribute_variant (t1, attributes);
 438     }
 439
 440 }
 441
 442 /* Return the type of a conditional expression between pointers to
 443    possibly differently qualified versions of compatible types.
 444
 445    We assume that comp_target_types has already been done and returned
 446    nonzero; if that isn't so, this may crash.  */
 447
 448 static tree
 449 common_pointer_type (tree t1, tree t2)
 450 {
 451   tree attributes;
 452   tree pointed_to_1, mv1;
 453   tree pointed_to_2, mv2;
 454   tree target;
 455
 456   /* Save time if the two types are the same.  */
 457
 458   if (t1 == t2) return t1;
 459
 460   /* If one type is nonsense, use the other.  */
 461   if (t1 == error_mark_node)
 462     return t2;
 463   if (t2 == error_mark_node)
 464     return t1;
 465
 466   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 467               && TREE_CODE (t2) == POINTER_TYPE);
 468
 469   /* Merge the attributes.  */
 470   attributes = targetm.merge_type_attributes (t1, t2);
 471
 472   /* Find the composite type of the target types, and combine the
 473      qualifiers of the two types' targets.  Do not lose qualifiers on
 474      array element types by taking the TYPE_MAIN_VARIANT.  */
 475   mv1 = pointed_to_1 = TREE_TYPE (t1);
 476   mv2 = pointed_to_2 = TREE_TYPE (t2);
 477   if (TREE_CODE (mv1) != ARRAY_TYPE)
 478     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 479   if (TREE_CODE (mv2) != ARRAY_TYPE)
 480     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 481   target = composite_type (mv1, mv2);
 482   t1 = build_pointer_type (c_build_qualified_type
 483                            (target,
 484                             TYPE_QUALS (pointed_to_1) |
 485                             TYPE_QUALS (pointed_to_2)));
 486   return build_type_attribute_variant (t1, attributes);
 487 }
 488
 489 /* Return the common type for two arithmetic types under the usual
 490    arithmetic conversions.  The default conversions have already been
 491    applied, and enumerated types converted to their compatible integer
 492    types.  The resulting type is unqualified and has no attributes.
 493
 494    This is the type for the result of most arithmetic operations
 495    if the operands have the given two types.  */
 496
 497 static tree
 498 c_common_type (tree t1, tree t2)
 499 {
 500   enum tree_code code1;
 501   enum tree_code code2;
 502
 503   /* If one type is nonsense, use the other.  */
 504   if (t1 == error_mark_node)
 505     return t2;
 506   if (t2 == error_mark_node)
 507     return t1;
 508
 509   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 510     t1 = TYPE_MAIN_VARIANT (t1);
 511
 512   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 513     t2 = TYPE_MAIN_VARIANT (t2);
 514
 515   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 516     t1 = build_type_attribute_variant (t1, NULL_TREE);
 517
 518   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 519     t2 = build_type_attribute_variant (t2, NULL_TREE);
 520
 521   /* Save time if the two types are the same.  */
 522
 523   if (t1 == t2) return t1;
 524
 525   code1 = TREE_CODE (t1);
 526   code2 = TREE_CODE (t2);
 527
 528   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 529               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 530   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 531               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 532
 533   /* If one type is a vector type, return that type.  (How the usual
 534      arithmetic conversions apply to the vector types extension is not
 535      precisely specified.)  */
 536   if (code1 == VECTOR_TYPE)
 537     return t1;
 538
 539   if (code2 == VECTOR_TYPE)
 540     return t2;
 541
 542   /* If one type is complex, form the common type of the non-complex
 543      components, then make that complex.  Use T1 or T2 if it is the
 544      required type.  */
 545   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 546     {
 547       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 548       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 549       tree subtype = c_common_type (subtype1, subtype2);
 550
 551       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 552         return t1;
 553       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 554         return t2;
 555       else
 556         return build_complex_type (subtype);
 557     }
 558
 559   /* If only one is real, use it as the result.  */
 560
 561   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 562     return t1;
 563
 564   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 565     return t2;
 566
 567   /* Both real or both integers; use the one with greater precision.  */
 568
 569   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 570     return t1;
 571   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 572     return t2;
 573
 574   /* Same precision.  Prefer long longs to longs to ints when the
 575      same precision, following the C99 rules on integer type rank
 576      (which are equivalent to the C90 rules for C90 types).  */
 577
 578   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 579       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 580     return long_long_unsigned_type_node;
 581
 582   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 583       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 584     {
 585       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 586         return long_long_unsigned_type_node;
 587       else
 588         return long_long_integer_type_node;
 589     }
 590
 591   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 592       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 593     return long_unsigned_type_node;
 594
 595   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 596       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 597     {
 598       /* But preserve unsignedness from the other type,
 599          since long cannot hold all the values of an unsigned int.  */
 600       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 601         return long_unsigned_type_node;
 602       else
 603         return long_integer_type_node;
 604     }
 605
 606   /* Likewise, prefer long double to double even if same size.  */
 607   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 608       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 609     return long_double_type_node;
 610
 611   /* Otherwise prefer the unsigned one.  */
 612
 613   if (TYPE_UNSIGNED (t1))
 614     return t1;
 615   else
 616     return t2;
 617 }
 618 \f
 619 /* Wrapper around c_common_type that is used by c-common.c.  ENUMERAL_TYPEs
 620    are allowed here and are converted to their compatible integer types.
 621    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 622    preferably a non-Boolean type as the common type.  */
 623 tree
 624 common_type (tree t1, tree t2)
 625 {
 626   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 627     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 628   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 629     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 630
 631   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 632   if (TREE_CODE (t1) == BOOLEAN_TYPE
 633       && TREE_CODE (t2) == BOOLEAN_TYPE)
 634     return boolean_type_node;
 635
 636   /* If either type is BOOLEAN_TYPE, then return the other.  */
 637   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 638     return t2;
 639   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 640     return t1;
 641
 642   return c_common_type (t1, t2);
 643 }
 644 \f
 645 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 646    or various other operations.  Return 2 if they are compatible
 647    but a warning may be needed if you use them together.  */
 648
 649 int
 650 comptypes (tree type1, tree type2)
 651 {
 652   tree t1 = type1;
 653   tree t2 = type2;
 654   int attrval, val;
 655
 656   /* Suppress errors caused by previously reported errors.  */
 657
 658   if (t1 == t2 || !t1 || !t2
 659       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 660     return 1;
 661
 662   /* If either type is the internal version of sizetype, return the
 663      language version.  */
 664   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 665       && TYPE_ORIG_SIZE_TYPE (t1))
 666     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 667
 668   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 669       && TYPE_ORIG_SIZE_TYPE (t2))
 670     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 671
 672
 673   /* Enumerated types are compatible with integer types, but this is
 674      not transitive: two enumerated types in the same translation unit
 675      are compatible with each other only if they are the same type.  */
 676
 677   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 678     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 679   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 680     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 681
 682   if (t1 == t2)
 683     return 1;
 684
 685   /* Different classes of types can't be compatible.  */
 686
 687   if (TREE_CODE (t1) != TREE_CODE (t2))
 688     return 0;
 689
 690   /* Qualifiers must match. C99 6.7.3p9 */
 691
 692   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 693     return 0;
 694
 695   /* Allow for two different type nodes which have essentially the same
 696      definition.  Note that we already checked for equality of the type
 697      qualifiers (just above).  */
 698
 699   if (TREE_CODE (t1) != ARRAY_TYPE
 700       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 701     return 1;
 702
 703   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 704   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 705      return 0;
 706
 707   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 708   val = 0;
 709
 710   switch (TREE_CODE (t1))
 711     {
 712     case POINTER_TYPE:
 713       /* Do not remove mode or aliasing information.  */
 714       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 715           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 716         break;
 717       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 718              ? 1 : comptypes (TREE_TYPE (t1), TREE_TYPE (t2)));
 719       break;
 720
 721     case FUNCTION_TYPE:
 722       val = function_types_compatible_p (t1, t2);
 723       break;
 724
 725     case ARRAY_TYPE:
 726       {
 727         tree d1 = TYPE_DOMAIN (t1);
 728         tree d2 = TYPE_DOMAIN (t2);
 729         bool d1_variable, d2_variable;
 730         bool d1_zero, d2_zero;
 731         val = 1;
 732
 733         /* Target types must match incl. qualifiers.  */
 734         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 735             && 0 == (val = comptypes (TREE_TYPE (t1), TREE_TYPE (t2))))
 736           return 0;
 737
 738         /* Sizes must match unless one is missing or variable.  */
 739         if (d1 == 0 || d2 == 0 || d1 == d2)
 740           break;
 741
 742         d1_zero = !TYPE_MAX_VALUE (d1);
 743         d2_zero = !TYPE_MAX_VALUE (d2);
 744
 745         d1_variable = (!d1_zero
 746                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 747                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 748         d2_variable = (!d2_zero
 749                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 750                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 751
 752         if (d1_variable || d2_variable)
 753           break;
 754         if (d1_zero && d2_zero)
 755           break;
 756         if (d1_zero || d2_zero
 757             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 758             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 759           val = 0;
 760
 761         break;
 762       }
 763
 764     case ENUMERAL_TYPE:
 765     case RECORD_TYPE:
 766     case UNION_TYPE:
 767       if (val != 1 && !same_translation_unit_p (t1, t2))
 768         val = tagged_types_tu_compatible_p (t1, t2);
 769       break;
 770
 771     case VECTOR_TYPE:
 772       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 773             && comptypes (TREE_TYPE (t1), TREE_TYPE (t2));
 774       break;
 775
 776     default:
 777       break;
 778     }
 779   return attrval == 2 && val == 1 ? 2 : val;
 780 }
 781
 782 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 783    ignoring their qualifiers.  */
 784
 785 static int
 786 comp_target_types (tree ttl, tree ttr)
 787 {
 788   int val;
 789   tree mvl, mvr;
 790
 791   /* Do not lose qualifiers on element types of array types that are
 792      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 793   mvl = TREE_TYPE (ttl);
 794   mvr = TREE_TYPE (ttr);
 795   if (TREE_CODE (mvl) != ARRAY_TYPE)
 796     mvl = TYPE_MAIN_VARIANT (mvl);
 797   if (TREE_CODE (mvr) != ARRAY_TYPE)
 798     mvr = TYPE_MAIN_VARIANT (mvr);
 799   val = comptypes (mvl, mvr);
 800
 801   if (val == 2 && pedantic)
 802     pedwarn ("types are not quite compatible");
 803   return val;
 804 }
 805 \f
 806 /* Subroutines of `comptypes'.  */
 807
 808 /* Determine whether two trees derive from the same translation unit.
 809    If the CONTEXT chain ends in a null, that tree's context is still
 810    being parsed, so if two trees have context chains ending in null,
 811    they're in the same translation unit.  */
 812 int
 813 same_translation_unit_p (tree t1, tree t2)
 814 {
 815   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 816     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 817       {
 818       case tcc_declaration:
 819         t1 = DECL_CONTEXT (t1); break;
 820       case tcc_type:
 821         t1 = TYPE_CONTEXT (t1); break;
 822       case tcc_exceptional:
 823         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 824       default: gcc_unreachable ();
 825       }
 826
 827   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 828     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 829       {
 830       case tcc_declaration:
 831         t2 = DECL_CONTEXT (t2); break;
 832       case tcc_type:
 833         t2 = TYPE_CONTEXT (t2); break;
 834       case tcc_exceptional:
 835         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 836       default: gcc_unreachable ();
 837       }
 838
 839   return t1 == t2;
 840 }
 841
 842 /* The C standard says that two structures in different translation
 843    units are compatible with each other only if the types of their
 844    fields are compatible (among other things).  So, consider two copies
 845    of this structure:  */
 846
 847 struct tagged_tu_seen {
 848   const struct tagged_tu_seen * next;
 849   tree t1;
 850   tree t2;
 851 };
 852
 853 /* Can they be compatible with each other?  We choose to break the
 854    recursion by allowing those types to be compatible.  */
 855
 856 static const struct tagged_tu_seen * tagged_tu_seen_base;
 857
 858 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 859    compatible.  If the two types are not the same (which has been
 860    checked earlier), this can only happen when multiple translation
 861    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 862    rules.  */
 863
 864 static int
 865 tagged_types_tu_compatible_p (tree t1, tree t2)
 866 {
 867   tree s1, s2;
 868   bool needs_warning = false;
 869
 870   /* We have to verify that the tags of the types are the same.  This
 871      is harder than it looks because this may be a typedef, so we have
 872      to go look at the original type.  It may even be a typedef of a
 873      typedef...
 874      In the case of compiler-created builtin structs the TYPE_DECL
 875      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 876   while (TYPE_NAME (t1)
 877          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 878          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 879     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 880
 881   while (TYPE_NAME (t2)
 882          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
 883          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
 884     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
 885
 886   /* C90 didn't have the requirement that the two tags be the same.  */
 887   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
 888     return 0;
 889
 890   /* C90 didn't say what happened if one or both of the types were
 891      incomplete; we choose to follow C99 rules here, which is that they
 892      are compatible.  */
 893   if (TYPE_SIZE (t1) == NULL
 894       || TYPE_SIZE (t2) == NULL)
 895     return 1;
 896
 897   {
 898     const struct tagged_tu_seen * tts_i;
 899     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
 900       if (tts_i->t1 == t1 && tts_i->t2 == t2)
 901         return 1;
 902   }
 903
 904   switch (TREE_CODE (t1))
 905     {
 906     case ENUMERAL_TYPE:
 907       {
 908
 909         /* Speed up the case where the type values are in the same order.  */
 910         tree tv1 = TYPE_VALUES (t1);
 911         tree tv2 = TYPE_VALUES (t2);
 912
 913         if (tv1 == tv2)
 914           return 1;
 915
 916         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
 917           {
 918             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
 919               break;
 920             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
 921               return 0;
 922           }
 923
 924         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
 925           return 1;
 926         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
 927           return 0;
 928
 929         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
 930           return 0;
 931
 932         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
 933           {
 934             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
 935             if (s2 == NULL
 936                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
 937               return 0;
 938           }
 939         return 1;
 940       }
 941
 942     case UNION_TYPE:
 943       {
 944         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
 945           return 0;
 946
 947         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
 948           {
 949             bool ok = false;
 950             struct tagged_tu_seen tts;
 951
 952             tts.next = tagged_tu_seen_base;
 953             tts.t1 = t1;
 954             tts.t2 = t2;
 955             tagged_tu_seen_base = &tts;
 956
 957             if (DECL_NAME (s1) != NULL)
 958               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
 959                 if (DECL_NAME (s1) == DECL_NAME (s2))
 960                   {
 961                     int result;
 962                     result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
 963                     if (result == 0)
 964                       break;
 965                     if (result == 2)
 966                       needs_warning = true;
 967
 968                     if (TREE_CODE (s1) == FIELD_DECL
 969                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
 970                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
 971                       break;
 972
 973                     ok = true;
 974                     break;
 975                   }
 976             tagged_tu_seen_base = tts.next;
 977             if (!ok)
 978               return 0;
 979           }
 980         return needs_warning ? 2 : 1;
 981       }
 982
 983     case RECORD_TYPE:
 984       {
 985         struct tagged_tu_seen tts;
 986
 987         tts.next = tagged_tu_seen_base;
 988         tts.t1 = t1;
 989         tts.t2 = t2;
 990         tagged_tu_seen_base = &tts;
 991
 992         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
 993              s1 && s2;
 994              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
 995           {
 996             int result;
 997             if (TREE_CODE (s1) != TREE_CODE (s2)
 998                 || DECL_NAME (s1) != DECL_NAME (s2))
 999               break;
1000             result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
1001             if (result == 0)
1002               break;
1003             if (result == 2)
1004               needs_warning = true;
1005
1006             if (TREE_CODE (s1) == FIELD_DECL
1007                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1008                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1009               break;
1010           }
1011         tagged_tu_seen_base = tts.next;
1012         if (s1 && s2)
1013           return 0;
1014         return needs_warning ? 2 : 1;
1015       }
1016
1017     default:
1018       gcc_unreachable ();
1019     }
1020 }
1021
1022 /* Return 1 if two function types F1 and F2 are compatible.
1023    If either type specifies no argument types,
1024    the other must specify a fixed number of self-promoting arg types.
1025    Otherwise, if one type specifies only the number of arguments,
1026    the other must specify that number of self-promoting arg types.
1027    Otherwise, the argument types must match.  */
1028
1029 static int
1030 function_types_compatible_p (tree f1, tree f2)
1031 {
1032   tree args1, args2;
1033   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1034   int val = 1;
1035   int val1;
1036   tree ret1, ret2;
1037
1038   ret1 = TREE_TYPE (f1);
1039   ret2 = TREE_TYPE (f2);
1040
1041   /* 'volatile' qualifiers on a function's return type used to mean
1042      the function is noreturn.  */
1043   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1044     pedwarn ("function return types not compatible due to %<volatile%>");
1045   if (TYPE_VOLATILE (ret1))
1046     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1047                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1048   if (TYPE_VOLATILE (ret2))
1049     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1050                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1051   val = comptypes (ret1, ret2);
1052   if (val == 0)
1053     return 0;
1054
1055   args1 = TYPE_ARG_TYPES (f1);
1056   args2 = TYPE_ARG_TYPES (f2);
1057
1058   /* An unspecified parmlist matches any specified parmlist
1059      whose argument types don't need default promotions.  */
1060
1061   if (args1 == 0)
1062     {
1063       if (!self_promoting_args_p (args2))
1064         return 0;
1065       /* If one of these types comes from a non-prototype fn definition,
1066          compare that with the other type's arglist.
1067          If they don't match, ask for a warning (0, but no error).  */
1068       if (TYPE_ACTUAL_ARG_TYPES (f1)
1069           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1070         val = 2;
1071       return val;
1072     }
1073   if (args2 == 0)
1074     {
1075       if (!self_promoting_args_p (args1))
1076         return 0;
1077       if (TYPE_ACTUAL_ARG_TYPES (f2)
1078           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1079         val = 2;
1080       return val;
1081     }
1082
1083   /* Both types have argument lists: compare them and propagate results.  */
1084   val1 = type_lists_compatible_p (args1, args2);
1085   return val1 != 1 ? val1 : val;
1086 }
1087
1088 /* Check two lists of types for compatibility,
1089    returning 0 for incompatible, 1 for compatible,
1090    or 2 for compatible with warning.  */
1091
1092 static int
1093 type_lists_compatible_p (tree args1, tree args2)
1094 {
1095   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1096   int val = 1;
1097   int newval = 0;
1098
1099   while (1)
1100     {
1101       tree a1, mv1, a2, mv2;
1102       if (args1 == 0 && args2 == 0)
1103         return val;
1104       /* If one list is shorter than the other,
1105          they fail to match.  */
1106       if (args1 == 0 || args2 == 0)
1107         return 0;
1108       mv1 = a1 = TREE_VALUE (args1);
1109       mv2 = a2 = TREE_VALUE (args2);
1110       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1111         mv1 = TYPE_MAIN_VARIANT (mv1);
1112       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1113         mv2 = TYPE_MAIN_VARIANT (mv2);
1114       /* A null pointer instead of a type
1115          means there is supposed to be an argument
1116          but nothing is specified about what type it has.
1117          So match anything that self-promotes.  */
1118       if (a1 == 0)
1119         {
1120           if (c_type_promotes_to (a2) != a2)
1121             return 0;
1122         }
1123       else if (a2 == 0)
1124         {
1125           if (c_type_promotes_to (a1) != a1)
1126             return 0;
1127         }
1128       /* If one of the lists has an error marker, ignore this arg.  */
1129       else if (TREE_CODE (a1) == ERROR_MARK
1130                || TREE_CODE (a2) == ERROR_MARK)
1131         ;
1132       else if (!(newval = comptypes (mv1, mv2)))
1133         {
1134           /* Allow  wait (union {union wait *u; int *i} *)
1135              and  wait (union wait *)  to be compatible.  */
1136           if (TREE_CODE (a1) == UNION_TYPE
1137               && (TYPE_NAME (a1) == 0
1138                   || TYPE_TRANSPARENT_UNION (a1))
1139               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1140               && tree_int_cst_equal (TYPE_SIZE (a1),
1141                                      TYPE_SIZE (a2)))
1142             {
1143               tree memb;
1144               for (memb = TYPE_FIELDS (a1);
1145                    memb; memb = TREE_CHAIN (memb))
1146                 {
1147                   tree mv3 = TREE_TYPE (memb);
1148                   if (mv3 && mv3 != error_mark_node
1149                       && TREE_CODE (mv3) != ARRAY_TYPE)
1150                     mv3 = TYPE_MAIN_VARIANT (mv3);
1151                   if (comptypes (mv3, mv2))
1152                     break;
1153                 }
1154               if (memb == 0)
1155                 return 0;
1156             }
1157           else if (TREE_CODE (a2) == UNION_TYPE
1158                    && (TYPE_NAME (a2) == 0
1159                        || TYPE_TRANSPARENT_UNION (a2))
1160                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1161                    && tree_int_cst_equal (TYPE_SIZE (a2),
1162                                           TYPE_SIZE (a1)))
1163             {
1164               tree memb;
1165               for (memb = TYPE_FIELDS (a2);
1166                    memb; memb = TREE_CHAIN (memb))
1167                 {
1168                   tree mv3 = TREE_TYPE (memb);
1169                   if (mv3 && mv3 != error_mark_node
1170                       && TREE_CODE (mv3) != ARRAY_TYPE)
1171                     mv3 = TYPE_MAIN_VARIANT (mv3);
1172                   if (comptypes (mv3, mv1))
1173                     break;
1174                 }
1175               if (memb == 0)
1176                 return 0;
1177             }
1178           else
1179             return 0;
1180         }
1181
1182       /* comptypes said ok, but record if it said to warn.  */
1183       if (newval > val)
1184         val = newval;
1185
1186       args1 = TREE_CHAIN (args1);
1187       args2 = TREE_CHAIN (args2);
1188     }
1189 }
1190 \f
1191 /* Compute the size to increment a pointer by.  */
1192
1193 static tree
1194 c_size_in_bytes (tree type)
1195 {
1196   enum tree_code code = TREE_CODE (type);
1197
1198   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1199     return size_one_node;
1200
1201   if (!COMPLETE_OR_VOID_TYPE_P (type))
1202     {
1203       error ("arithmetic on pointer to an incomplete type");
1204       return size_one_node;
1205     }
1206
1207   /* Convert in case a char is more than one unit.  */
1208   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1209                      size_int (TYPE_PRECISION (char_type_node)
1210                                / BITS_PER_UNIT));
1211 }
1212 \f
1213 /* Return either DECL or its known constant value (if it has one).  */
1214
1215 tree
1216 decl_constant_value (tree decl)
1217 {
1218   if (/* Don't change a variable array bound or initial value to a constant
1219          in a place where a variable is invalid.  Note that DECL_INITIAL
1220          isn't valid for a PARM_DECL.  */
1221       current_function_decl != 0
1222       && TREE_CODE (decl) != PARM_DECL
1223       && !TREE_THIS_VOLATILE (decl)
1224       && TREE_READONLY (decl)
1225       && DECL_INITIAL (decl) != 0
1226       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1227       /* This is invalid if initial value is not constant.
1228          If it has either a function call, a memory reference,
1229          or a variable, then re-evaluating it could give different results.  */
1230       && TREE_CONSTANT (DECL_INITIAL (decl))
1231       /* Check for cases where this is sub-optimal, even though valid.  */
1232       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1233     return DECL_INITIAL (decl);
1234   return decl;
1235 }
1236
1237 /* Return either DECL or its known constant value (if it has one), but
1238    return DECL if pedantic or DECL has mode BLKmode.  This is for
1239    bug-compatibility with the old behavior of decl_constant_value
1240    (before GCC 3.0); every use of this function is a bug and it should
1241    be removed before GCC 3.1.  It is not appropriate to use pedantic
1242    in a way that affects optimization, and BLKmode is probably not the
1243    right test for avoiding misoptimizations either.  */
1244
1245 static tree
1246 decl_constant_value_for_broken_optimization (tree decl)
1247 {
1248   tree ret;
1249
1250   if (pedantic || DECL_MODE (decl) == BLKmode)
1251     return decl;
1252
1253   ret = decl_constant_value (decl);
1254   /* Avoid unwanted tree sharing between the initializer and current
1255      function's body where the tree can be modified e.g. by the
1256      gimplifier.  */
1257   if (ret != decl && TREE_STATIC (decl))
1258     ret = unshare_expr (ret);
1259   return ret;
1260 }
1261
1262
1263 /* Perform the default conversion of arrays and functions to pointers.
1264    Return the result of converting EXP.  For any other expression, just
1265    return EXP after removing NOPs.  */
1266
1267 tree
1268 default_function_array_conversion (tree exp)
1269 {
1270   tree orig_exp;
1271   tree type = TREE_TYPE (exp);
1272   enum tree_code code = TREE_CODE (type);
1273   int not_lvalue = 0;
1274
1275   /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1276      an lvalue.
1277
1278      Do not use STRIP_NOPS here!  It will remove conversions from pointer
1279      to integer and cause infinite recursion.  */
1280   orig_exp = exp;
1281   while (TREE_CODE (exp) == NON_LVALUE_EXPR
1282          || (TREE_CODE (exp) == NOP_EXPR
1283              && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
1284     {
1285       if (TREE_CODE (exp) == NON_LVALUE_EXPR)
1286         not_lvalue = 1;
1287       exp = TREE_OPERAND (exp, 0);
1288     }
1289
1290   if (TREE_NO_WARNING (orig_exp))
1291     TREE_NO_WARNING (exp) = 1;
1292
1293   if (code == FUNCTION_TYPE)
1294     {
1295       return build_unary_op (ADDR_EXPR, exp, 0);
1296     }
1297   if (code == ARRAY_TYPE)
1298     {
1299       tree adr;
1300       tree restype = TREE_TYPE (type);
1301       tree ptrtype;
1302       int constp = 0;
1303       int volatilep = 0;
1304       int lvalue_array_p;
1305
1306       if (REFERENCE_CLASS_P (exp) || DECL_P (exp))
1307         {
1308           constp = TREE_READONLY (exp);
1309           volatilep = TREE_THIS_VOLATILE (exp);
1310         }
1311
1312       if (TYPE_QUALS (type) || constp || volatilep)
1313         restype
1314           = c_build_qualified_type (restype,
1315                                     TYPE_QUALS (type)
1316                                     | (constp * TYPE_QUAL_CONST)
1317                                     | (volatilep * TYPE_QUAL_VOLATILE));
1318
1319       if (TREE_CODE (exp) == INDIRECT_REF)
1320         return convert (build_pointer_type (restype),
1321                         TREE_OPERAND (exp, 0));
1322
1323       if (TREE_CODE (exp) == COMPOUND_EXPR)
1324         {
1325           tree op1 = default_conversion (TREE_OPERAND (exp, 1));
1326           return build2 (COMPOUND_EXPR, TREE_TYPE (op1),
1327                          TREE_OPERAND (exp, 0), op1);
1328         }
1329
1330       lvalue_array_p = !not_lvalue && lvalue_p (exp);
1331       if (!flag_isoc99 && !lvalue_array_p)
1332         {
1333           /* Before C99, non-lvalue arrays do not decay to pointers.
1334              Normally, using such an array would be invalid; but it can
1335              be used correctly inside sizeof or as a statement expression.
1336              Thus, do not give an error here; an error will result later.  */
1337           return exp;
1338         }
1339
1340       ptrtype = build_pointer_type (restype);
1341
1342       if (TREE_CODE (exp) == VAR_DECL)
1343         {
1344           /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1345              ADDR_EXPR because it's the best way of representing what
1346              happens in C when we take the address of an array and place
1347              it in a pointer to the element type.  */
1348           adr = build1 (ADDR_EXPR, ptrtype, exp);
1349           if (!c_mark_addressable (exp))
1350             return error_mark_node;
1351           TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1352           return adr;
1353         }
1354       /* This way is better for a COMPONENT_REF since it can
1355          simplify the offset for a component.  */
1356       adr = build_unary_op (ADDR_EXPR, exp, 1);
1357       return convert (ptrtype, adr);
1358     }
1359   return exp;
1360 }
1361
1362
1363 /* EXP is an expression of integer type.  Apply the integer promotions
1364    to it and return the promoted value.  */
1365
1366 tree
1367 perform_integral_promotions (tree exp)
1368 {
1369   tree type = TREE_TYPE (exp);
1370   enum tree_code code = TREE_CODE (type);
1371
1372   gcc_assert (INTEGRAL_TYPE_P (type));
1373
1374   /* Normally convert enums to int,
1375      but convert wide enums to something wider.  */
1376   if (code == ENUMERAL_TYPE)
1377     {
1378       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1379                                           TYPE_PRECISION (integer_type_node)),
1380                                      ((TYPE_PRECISION (type)
1381                                        >= TYPE_PRECISION (integer_type_node))
1382                                       && TYPE_UNSIGNED (type)));
1383
1384       return convert (type, exp);
1385     }
1386
1387   /* ??? This should no longer be needed now bit-fields have their
1388      proper types.  */
1389   if (TREE_CODE (exp) == COMPONENT_REF
1390       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1391       /* If it's thinner than an int, promote it like a
1392          c_promoting_integer_type_p, otherwise leave it alone.  */
1393       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1394                                TYPE_PRECISION (integer_type_node)))
1395     return convert (integer_type_node, exp);
1396
1397   if (c_promoting_integer_type_p (type))
1398     {
1399       /* Preserve unsignedness if not really getting any wider.  */
1400       if (TYPE_UNSIGNED (type)
1401           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1402         return convert (unsigned_type_node, exp);
1403
1404       return convert (integer_type_node, exp);
1405     }
1406
1407   return exp;
1408 }
1409
1410
1411 /* Perform default promotions for C data used in expressions.
1412    Enumeral types or short or char are converted to int.
1413    In addition, manifest constants symbols are replaced by their values.  */
1414
1415 tree
1416 default_conversion (tree exp)
1417 {
1418   tree orig_exp;
1419   tree type = TREE_TYPE (exp);
1420   enum tree_code code = TREE_CODE (type);
1421
1422   /* Functions and arrays have been converted during parsing.  */
1423   gcc_assert (code != FUNCTION_TYPE);
1424   if (code == ARRAY_TYPE)
1425     return exp;
1426
1427   /* Constants can be used directly unless they're not loadable.  */
1428   if (TREE_CODE (exp) == CONST_DECL)
1429     exp = DECL_INITIAL (exp);
1430
1431   /* Replace a nonvolatile const static variable with its value unless
1432      it is an array, in which case we must be sure that taking the
1433      address of the array produces consistent results.  */
1434   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1435     {
1436       exp = decl_constant_value_for_broken_optimization (exp);
1437       type = TREE_TYPE (exp);
1438     }
1439
1440   /* Strip no-op conversions.  */
1441   orig_exp = exp;
1442   STRIP_TYPE_NOPS (exp);
1443
1444   if (TREE_NO_WARNING (orig_exp))
1445     TREE_NO_WARNING (exp) = 1;
1446
1447   if (INTEGRAL_TYPE_P (type))
1448     return perform_integral_promotions (exp);
1449
1450   if (code == VOID_TYPE)
1451     {
1452       error ("void value not ignored as it ought to be");
1453       return error_mark_node;
1454     }
1455   return exp;
1456 }
1457 \f
1458 /* Look up COMPONENT in a structure or union DECL.
1459
1460    If the component name is not found, returns NULL_TREE.  Otherwise,
1461    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1462    stepping down the chain to the component, which is in the last
1463    TREE_VALUE of the list.  Normally the list is of length one, but if
1464    the component is embedded within (nested) anonymous structures or
1465    unions, the list steps down the chain to the component.  */
1466
1467 static tree
1468 lookup_field (tree decl, tree component)
1469 {
1470   tree type = TREE_TYPE (decl);
1471   tree field;
1472
1473   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1474      to the field elements.  Use a binary search on this array to quickly
1475      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1476      will always be set for structures which have many elements.  */
1477
1478   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1479     {
1480       int bot, top, half;
1481       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1482
1483       field = TYPE_FIELDS (type);
1484       bot = 0;
1485       top = TYPE_LANG_SPECIFIC (type)->s->len;
1486       while (top - bot > 1)
1487         {
1488           half = (top - bot + 1) >> 1;
1489           field = field_array[bot+half];
1490
1491           if (DECL_NAME (field) == NULL_TREE)
1492             {
1493               /* Step through all anon unions in linear fashion.  */
1494               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1495                 {
1496                   field = field_array[bot++];
1497                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1498                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1499                     {
1500                       tree anon = lookup_field (field, component);
1501
1502                       if (anon)
1503                         return tree_cons (NULL_TREE, field, anon);
1504                     }
1505                 }
1506
1507               /* Entire record is only anon unions.  */
1508               if (bot > top)
1509                 return NULL_TREE;
1510
1511               /* Restart the binary search, with new lower bound.  */
1512               continue;
1513             }
1514
1515           if (DECL_NAME (field) == component)
1516             break;
1517           if (DECL_NAME (field) < component)
1518             bot += half;
1519           else
1520             top = bot + half;
1521         }
1522
1523       if (DECL_NAME (field_array[bot]) == component)
1524         field = field_array[bot];
1525       else if (DECL_NAME (field) != component)
1526         return NULL_TREE;
1527     }
1528   else
1529     {
1530       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1531         {
1532           if (DECL_NAME (field) == NULL_TREE
1533               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1534                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1535             {
1536               tree anon = lookup_field (field, component);
1537
1538               if (anon)
1539                 return tree_cons (NULL_TREE, field, anon);
1540             }
1541
1542           if (DECL_NAME (field) == component)
1543             break;
1544         }
1545
1546       if (field == NULL_TREE)
1547         return NULL_TREE;
1548     }
1549
1550   return tree_cons (NULL_TREE, field, NULL_TREE);
1551 }
1552
1553 /* Make an expression to refer to the COMPONENT field of
1554    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1555
1556 tree
1557 build_component_ref (tree datum, tree component)
1558 {
1559   tree type = TREE_TYPE (datum);
1560   enum tree_code code = TREE_CODE (type);
1561   tree field = NULL;
1562   tree ref;
1563
1564   if (!objc_is_public (datum, component))
1565     return error_mark_node;
1566
1567   /* See if there is a field or component with name COMPONENT.  */
1568
1569   if (code == RECORD_TYPE || code == UNION_TYPE)
1570     {
1571       if (!COMPLETE_TYPE_P (type))
1572         {
1573           c_incomplete_type_error (NULL_TREE, type);
1574           return error_mark_node;
1575         }
1576
1577       field = lookup_field (datum, component);
1578
1579       if (!field)
1580         {
1581           error ("%qT has no member named %qE", type, component);
1582           return error_mark_node;
1583         }
1584
1585       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1586          This might be better solved in future the way the C++ front
1587          end does it - by giving the anonymous entities each a
1588          separate name and type, and then have build_component_ref
1589          recursively call itself.  We can't do that here.  */
1590       do
1591         {
1592           tree subdatum = TREE_VALUE (field);
1593
1594           if (TREE_TYPE (subdatum) == error_mark_node)
1595             return error_mark_node;
1596
1597           ref = build3 (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1598                         NULL_TREE);
1599           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1600             TREE_READONLY (ref) = 1;
1601           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1602             TREE_THIS_VOLATILE (ref) = 1;
1603
1604           if (TREE_DEPRECATED (subdatum))
1605             warn_deprecated_use (subdatum);
1606
1607           datum = ref;
1608
1609           field = TREE_CHAIN (field);
1610         }
1611       while (field);
1612
1613       return ref;
1614     }
1615   else if (code != ERROR_MARK)
1616     error ("request for member %qE in something not a structure or union",
1617            component);
1618
1619   return error_mark_node;
1620 }
1621 \f
1622 /* Given an expression PTR for a pointer, return an expression
1623    for the value pointed to.
1624    ERRORSTRING is the name of the operator to appear in error messages.  */
1625
1626 tree
1627 build_indirect_ref (tree ptr, const char *errorstring)
1628 {
1629   tree pointer = default_conversion (ptr);
1630   tree type = TREE_TYPE (pointer);
1631
1632   if (TREE_CODE (type) == POINTER_TYPE)
1633     {
1634       if (TREE_CODE (pointer) == ADDR_EXPR
1635           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1636               == TREE_TYPE (type)))
1637         return TREE_OPERAND (pointer, 0);
1638       else
1639         {
1640           tree t = TREE_TYPE (type);
1641           tree ref;
1642
1643           ref = build1 (INDIRECT_REF, t, pointer);
1644
1645           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1646             {
1647               error ("dereferencing pointer to incomplete type");
1648               return error_mark_node;
1649             }
1650           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1651             warning (0, "dereferencing %<void *%> pointer");
1652
1653           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1654              so that we get the proper error message if the result is used
1655              to assign to.  Also, &* is supposed to be a no-op.
1656              And ANSI C seems to specify that the type of the result
1657              should be the const type.  */
1658           /* A de-reference of a pointer to const is not a const.  It is valid
1659              to change it via some other pointer.  */
1660           TREE_READONLY (ref) = TYPE_READONLY (t);
1661           TREE_SIDE_EFFECTS (ref)
1662             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1663           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1664           return ref;
1665         }
1666     }
1667   else if (TREE_CODE (pointer) != ERROR_MARK)
1668     error ("invalid type argument of %qs", errorstring);
1669   return error_mark_node;
1670 }
1671
1672 /* This handles expressions of the form "a[i]", which denotes
1673    an array reference.
1674
1675    This is logically equivalent in C to *(a+i), but we may do it differently.
1676    If A is a variable or a member, we generate a primitive ARRAY_REF.
1677    This avoids forcing the array out of registers, and can work on
1678    arrays that are not lvalues (for example, members of structures returned
1679    by functions).  */
1680
1681 tree
1682 build_array_ref (tree array, tree index)
1683 {
1684   bool swapped = false;
1685   if (TREE_TYPE (array) == error_mark_node
1686       || TREE_TYPE (index) == error_mark_node)
1687     return error_mark_node;
1688
1689   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1690       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1691     {
1692       tree temp;
1693       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1694           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1695         {
1696           error ("subscripted value is neither array nor pointer");
1697           return error_mark_node;
1698         }
1699       temp = array;
1700       array = index;
1701       index = temp;
1702       swapped = true;
1703     }
1704
1705   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1706     {
1707       error ("array subscript is not an integer");
1708       return error_mark_node;
1709     }
1710
1711   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1712     {
1713       error ("subscripted value is pointer to function");
1714       return error_mark_node;
1715     }
1716
1717   /* Subscripting with type char is likely to lose on a machine where
1718      chars are signed.  So warn on any machine, but optionally.  Don't
1719      warn for unsigned char since that type is safe.  Don't warn for
1720      signed char because anyone who uses that must have done so
1721      deliberately.  ??? Existing practice has also been to warn only
1722      when the char index is syntactically the index, not for
1723      char[array].  */
1724   if (warn_char_subscripts && !swapped
1725       && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1726     warning (0, "array subscript has type %<char%>");
1727
1728   /* Apply default promotions *after* noticing character types.  */
1729   index = default_conversion (index);
1730
1731   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1732
1733   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1734     {
1735       tree rval, type;
1736
1737       /* An array that is indexed by a non-constant
1738          cannot be stored in a register; we must be able to do
1739          address arithmetic on its address.
1740          Likewise an array of elements of variable size.  */
1741       if (TREE_CODE (index) != INTEGER_CST
1742           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1743               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1744         {
1745           if (!c_mark_addressable (array))
1746             return error_mark_node;
1747         }
1748       /* An array that is indexed by a constant value which is not within
1749          the array bounds cannot be stored in a register either; because we
1750          would get a crash in store_bit_field/extract_bit_field when trying
1751          to access a non-existent part of the register.  */
1752       if (TREE_CODE (index) == INTEGER_CST
1753           && TYPE_DOMAIN (TREE_TYPE (array))
1754           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1755         {
1756           if (!c_mark_addressable (array))
1757             return error_mark_node;
1758         }
1759
1760       if (pedantic)
1761         {
1762           tree foo = array;
1763           while (TREE_CODE (foo) == COMPONENT_REF)
1764             foo = TREE_OPERAND (foo, 0);
1765           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1766             pedwarn ("ISO C forbids subscripting %<register%> array");
1767           else if (!flag_isoc99 && !lvalue_p (foo))
1768             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1769         }
1770
1771       type = TREE_TYPE (TREE_TYPE (array));
1772       if (TREE_CODE (type) != ARRAY_TYPE)
1773         type = TYPE_MAIN_VARIANT (type);
1774       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1775       /* Array ref is const/volatile if the array elements are
1776          or if the array is.  */
1777       TREE_READONLY (rval)
1778         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1779             | TREE_READONLY (array));
1780       TREE_SIDE_EFFECTS (rval)
1781         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1782             | TREE_SIDE_EFFECTS (array));
1783       TREE_THIS_VOLATILE (rval)
1784         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1785             /* This was added by rms on 16 Nov 91.
1786                It fixes  vol struct foo *a;  a->elts[1]
1787                in an inline function.
1788                Hope it doesn't break something else.  */
1789             | TREE_THIS_VOLATILE (array));
1790       return require_complete_type (fold (rval));
1791     }
1792   else
1793     {
1794       tree ar = default_conversion (array);
1795
1796       if (ar == error_mark_node)
1797         return ar;
1798
1799       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1800       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1801
1802       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1803                                  "array indexing");
1804     }
1805 }
1806 \f
1807 /* Build an external reference to identifier ID.  FUN indicates
1808    whether this will be used for a function call.  LOC is the source
1809    location of the identifier.  */
1810 tree
1811 build_external_ref (tree id, int fun, location_t loc)
1812 {
1813   tree ref;
1814   tree decl = lookup_name (id);
1815
1816   /* In Objective-C, an instance variable (ivar) may be preferred to
1817      whatever lookup_name() found.  */
1818   decl = objc_lookup_ivar (decl, id);
1819
1820   if (decl && decl != error_mark_node)
1821     ref = decl;
1822   else if (fun)
1823     /* Implicit function declaration.  */
1824     ref = implicitly_declare (id);
1825   else if (decl == error_mark_node)
1826     /* Don't complain about something that's already been
1827        complained about.  */
1828     return error_mark_node;
1829   else
1830     {
1831       undeclared_variable (id, loc);
1832       return error_mark_node;
1833     }
1834
1835   if (TREE_TYPE (ref) == error_mark_node)
1836     return error_mark_node;
1837
1838   if (TREE_DEPRECATED (ref))
1839     warn_deprecated_use (ref);
1840
1841   if (!skip_evaluation)
1842     assemble_external (ref);
1843   TREE_USED (ref) = 1;
1844
1845   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
1846     {
1847       if (!in_sizeof && !in_typeof)
1848         C_DECL_USED (ref) = 1;
1849       else if (DECL_INITIAL (ref) == 0
1850                && DECL_EXTERNAL (ref)
1851                && !TREE_PUBLIC (ref))
1852         record_maybe_used_decl (ref);
1853     }
1854
1855   if (TREE_CODE (ref) == CONST_DECL)
1856     {
1857       ref = DECL_INITIAL (ref);
1858       TREE_CONSTANT (ref) = 1;
1859       TREE_INVARIANT (ref) = 1;
1860     }
1861   else if (current_function_decl != 0
1862            && !DECL_FILE_SCOPE_P (current_function_decl)
1863            && (TREE_CODE (ref) == VAR_DECL
1864                || TREE_CODE (ref) == PARM_DECL
1865                || TREE_CODE (ref) == FUNCTION_DECL))
1866     {
1867       tree context = decl_function_context (ref);
1868
1869       if (context != 0 && context != current_function_decl)
1870         DECL_NONLOCAL (ref) = 1;
1871     }
1872
1873   return ref;
1874 }
1875
1876 /* Record details of decls possibly used inside sizeof or typeof.  */
1877 struct maybe_used_decl
1878 {
1879   /* The decl.  */
1880   tree decl;
1881   /* The level seen at (in_sizeof + in_typeof).  */
1882   int level;
1883   /* The next one at this level or above, or NULL.  */
1884   struct maybe_used_decl *next;
1885 };
1886
1887 static struct maybe_used_decl *maybe_used_decls;
1888
1889 /* Record that DECL, an undefined static function reference seen
1890    inside sizeof or typeof, might be used if the operand of sizeof is
1891    a VLA type or the operand of typeof is a variably modified
1892    type.  */
1893
1894 static void
1895 record_maybe_used_decl (tree decl)
1896 {
1897   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
1898   t->decl = decl;
1899   t->level = in_sizeof + in_typeof;
1900   t->next = maybe_used_decls;
1901   maybe_used_decls = t;
1902 }
1903
1904 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
1905    USED is false, just discard them.  If it is true, mark them used
1906    (if no longer inside sizeof or typeof) or move them to the next
1907    level up (if still inside sizeof or typeof).  */
1908
1909 void
1910 pop_maybe_used (bool used)
1911 {
1912   struct maybe_used_decl *p = maybe_used_decls;
1913   int cur_level = in_sizeof + in_typeof;
1914   while (p && p->level > cur_level)
1915     {
1916       if (used)
1917         {
1918           if (cur_level == 0)
1919             C_DECL_USED (p->decl) = 1;
1920           else
1921             p->level = cur_level;
1922         }
1923       p = p->next;
1924     }
1925   if (!used || cur_level == 0)
1926     maybe_used_decls = p;
1927 }
1928
1929 /* Return the result of sizeof applied to EXPR.  */
1930
1931 struct c_expr
1932 c_expr_sizeof_expr (struct c_expr expr)
1933 {
1934   struct c_expr ret;
1935   if (expr.value == error_mark_node)
1936     {
1937       ret.value = error_mark_node;
1938       ret.original_code = ERROR_MARK;
1939       pop_maybe_used (false);
1940     }
1941   else
1942     {
1943       ret.value = c_sizeof (TREE_TYPE (expr.value));
1944       ret.original_code = ERROR_MARK;
1945       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
1946     }
1947   return ret;
1948 }
1949
1950 /* Return the result of sizeof applied to T, a structure for the type
1951    name passed to sizeof (rather than the type itself).  */
1952
1953 struct c_expr
1954 c_expr_sizeof_type (struct c_type_name *t)
1955 {
1956   tree type;
1957   struct c_expr ret;
1958   type = groktypename (t);
1959   ret.value = c_sizeof (type);
1960   ret.original_code = ERROR_MARK;
1961   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
1962   return ret;
1963 }
1964
1965 /* Build a function call to function FUNCTION with parameters PARAMS.
1966    PARAMS is a list--a chain of TREE_LIST nodes--in which the
1967    TREE_VALUE of each node is a parameter-expression.
1968    FUNCTION's data type may be a function type or a pointer-to-function.  */
1969
1970 tree
1971 build_function_call (tree function, tree params)
1972 {
1973   tree fntype, fundecl = 0;
1974   tree coerced_params;
1975   tree name = NULL_TREE, result;
1976   tree tem;
1977
1978   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
1979   STRIP_TYPE_NOPS (function);
1980
1981   /* Convert anything with function type to a pointer-to-function.  */
1982   if (TREE_CODE (function) == FUNCTION_DECL)
1983     {
1984       /* Implement type-directed function overloading for builtins.
1985          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
1986          handle all the type checking.  The result is a complete expression
1987          that implements this function call.  */
1988       tem = resolve_overloaded_builtin (function, params);
1989       if (tem)
1990         return tem;
1991
1992       name = DECL_NAME (function);
1993       fundecl = function;
1994     }
1995   function = default_function_array_conversion (function);
1996
1997   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
1998      expressions, like those used for ObjC messenger dispatches.  */
1999   function = objc_rewrite_function_call (function, params);
2000
2001   fntype = TREE_TYPE (function);
2002
2003   if (TREE_CODE (fntype) == ERROR_MARK)
2004     return error_mark_node;
2005
2006   if (!(TREE_CODE (fntype) == POINTER_TYPE
2007         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2008     {
2009       error ("called object %qE is not a function", function);
2010       return error_mark_node;
2011     }
2012
2013   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2014     current_function_returns_abnormally = 1;
2015
2016   /* fntype now gets the type of function pointed to.  */
2017   fntype = TREE_TYPE (fntype);
2018
2019   /* Check that the function is called through a compatible prototype.
2020      If it is not, replace the call by a trap, wrapped up in a compound
2021      expression if necessary.  This has the nice side-effect to prevent
2022      the tree-inliner from generating invalid assignment trees which may
2023      blow up in the RTL expander later.  */
2024   if (TREE_CODE (function) == NOP_EXPR
2025       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2026       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2027       && !comptypes (fntype, TREE_TYPE (tem)))
2028     {
2029       tree return_type = TREE_TYPE (fntype);
2030       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2031                                        NULL_TREE);
2032
2033       /* This situation leads to run-time undefined behavior.  We can't,
2034          therefore, simply error unless we can prove that all possible
2035          executions of the program must execute the code.  */
2036       warning (0, "function called through a non-compatible type");
2037
2038       /* We can, however, treat "undefined" any way we please.
2039          Call abort to encourage the user to fix the program.  */
2040       inform ("if this code is reached, the program will abort");
2041
2042       if (VOID_TYPE_P (return_type))
2043         return trap;
2044       else
2045         {
2046           tree rhs;
2047
2048           if (AGGREGATE_TYPE_P (return_type))
2049             rhs = build_compound_literal (return_type,
2050                                           build_constructor (return_type,
2051                                                              NULL_TREE));
2052           else
2053             rhs = fold (build1 (NOP_EXPR, return_type, integer_zero_node));
2054
2055           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2056         }
2057     }
2058
2059   /* Convert the parameters to the types declared in the
2060      function prototype, or apply default promotions.  */
2061
2062   coerced_params
2063     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2064
2065   if (coerced_params == error_mark_node)
2066     return error_mark_node;
2067
2068   /* Check that the arguments to the function are valid.  */
2069
2070   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params);
2071
2072   result = build3 (CALL_EXPR, TREE_TYPE (fntype),
2073                    function, coerced_params, NULL_TREE);
2074   TREE_SIDE_EFFECTS (result) = 1;
2075
2076   if (require_constant_value)
2077     {
2078       result = fold_initializer (result);
2079
2080       if (TREE_CONSTANT (result)
2081           && (name == NULL_TREE
2082               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2083         pedwarn_init ("initializer element is not constant");
2084     }
2085   else
2086     result = fold (result);
2087
2088   if (VOID_TYPE_P (TREE_TYPE (result)))
2089     return result;
2090   return require_complete_type (result);
2091 }
2092 \f
2093 /* Convert the argument expressions in the list VALUES
2094    to the types in the list TYPELIST.  The result is a list of converted
2095    argument expressions, unless there are too few arguments in which
2096    case it is error_mark_node.
2097
2098    If TYPELIST is exhausted, or when an element has NULL as its type,
2099    perform the default conversions.
2100
2101    PARMLIST is the chain of parm decls for the function being called.
2102    It may be 0, if that info is not available.
2103    It is used only for generating error messages.
2104
2105    FUNCTION is a tree for the called function.  It is used only for
2106    error messages, where it is formatted with %qE.
2107
2108    This is also where warnings about wrong number of args are generated.
2109
2110    Both VALUES and the returned value are chains of TREE_LIST nodes
2111    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2112
2113 static tree
2114 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2115 {
2116   tree typetail, valtail;
2117   tree result = NULL;
2118   int parmnum;
2119   tree selector;
2120
2121   /* Change pointer to function to the function itself for
2122      diagnostics.  */
2123   if (TREE_CODE (function) == ADDR_EXPR
2124       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2125     function = TREE_OPERAND (function, 0);
2126
2127   /* Handle an ObjC selector specially for diagnostics.  */
2128   selector = objc_message_selector ();
2129
2130   /* Scan the given expressions and types, producing individual
2131      converted arguments and pushing them on RESULT in reverse order.  */
2132
2133   for (valtail = values, typetail = typelist, parmnum = 0;
2134        valtail;
2135        valtail = TREE_CHAIN (valtail), parmnum++)
2136     {
2137       tree type = typetail ? TREE_VALUE (typetail) : 0;
2138       tree val = TREE_VALUE (valtail);
2139       tree rname = function;
2140       int argnum = parmnum + 1;
2141       const char *invalid_func_diag;
2142
2143       if (type == void_type_node)
2144         {
2145           error ("too many arguments to function %qE", function);
2146           break;
2147         }
2148
2149       if (selector && argnum > 2)
2150         {
2151           rname = selector;
2152           argnum -= 2;
2153         }
2154
2155       STRIP_TYPE_NOPS (val);
2156
2157       val = require_complete_type (val);
2158
2159       if (type != 0)
2160         {
2161           /* Formal parm type is specified by a function prototype.  */
2162           tree parmval;
2163
2164           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2165             {
2166               error ("type of formal parameter %d is incomplete", parmnum + 1);
2167               parmval = val;
2168             }
2169           else
2170             {
2171               /* Optionally warn about conversions that
2172                  differ from the default conversions.  */
2173               if (warn_conversion || warn_traditional)
2174                 {
2175                   unsigned int formal_prec = TYPE_PRECISION (type);
2176
2177                   if (INTEGRAL_TYPE_P (type)
2178                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2179                     warning (0, "passing argument %d of %qE as integer "
2180                              "rather than floating due to prototype",
2181                              argnum, rname);
2182                   if (INTEGRAL_TYPE_P (type)
2183                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2184                     warning (0, "passing argument %d of %qE as integer "
2185                              "rather than complex due to prototype",
2186                              argnum, rname);
2187                   else if (TREE_CODE (type) == COMPLEX_TYPE
2188                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2189                     warning (0, "passing argument %d of %qE as complex "
2190                              "rather than floating due to prototype",
2191                              argnum, rname);
2192                   else if (TREE_CODE (type) == REAL_TYPE
2193                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2194                     warning (0, "passing argument %d of %qE as floating "
2195                              "rather than integer due to prototype",
2196                              argnum, rname);
2197                   else if (TREE_CODE (type) == COMPLEX_TYPE
2198                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2199                     warning (0, "passing argument %d of %qE as complex "
2200                              "rather than integer due to prototype",
2201                              argnum, rname);
2202                   else if (TREE_CODE (type) == REAL_TYPE
2203                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2204                     warning (0, "passing argument %d of %qE as floating "
2205                              "rather than complex due to prototype",
2206                              argnum, rname);
2207                   /* ??? At some point, messages should be written about
2208                      conversions between complex types, but that's too messy
2209                      to do now.  */
2210                   else if (TREE_CODE (type) == REAL_TYPE
2211                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2212                     {
2213                       /* Warn if any argument is passed as `float',
2214                          since without a prototype it would be `double'.  */
2215                       if (formal_prec == TYPE_PRECISION (float_type_node))
2216                         warning (0, "passing argument %d of %qE as %<float%> "
2217                                  "rather than %<double%> due to prototype",
2218                                  argnum, rname);
2219                     }
2220                   /* Detect integer changing in width or signedness.
2221                      These warnings are only activated with
2222                      -Wconversion, not with -Wtraditional.  */
2223                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2224                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2225                     {
2226                       tree would_have_been = default_conversion (val);
2227                       tree type1 = TREE_TYPE (would_have_been);
2228
2229                       if (TREE_CODE (type) == ENUMERAL_TYPE
2230                           && (TYPE_MAIN_VARIANT (type)
2231                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2232                         /* No warning if function asks for enum
2233                            and the actual arg is that enum type.  */
2234                         ;
2235                       else if (formal_prec != TYPE_PRECISION (type1))
2236                         warning (0, "passing argument %d of %qE with different "
2237                                  "width due to prototype", argnum, rname);
2238                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2239                         ;
2240                       /* Don't complain if the formal parameter type
2241                          is an enum, because we can't tell now whether
2242                          the value was an enum--even the same enum.  */
2243                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2244                         ;
2245                       else if (TREE_CODE (val) == INTEGER_CST
2246                                && int_fits_type_p (val, type))
2247                         /* Change in signedness doesn't matter
2248                            if a constant value is unaffected.  */
2249                         ;
2250                       /* If the value is extended from a narrower
2251                          unsigned type, it doesn't matter whether we
2252                          pass it as signed or unsigned; the value
2253                          certainly is the same either way.  */
2254                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2255                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2256                         ;
2257                       else if (TYPE_UNSIGNED (type))
2258                         warning (0, "passing argument %d of %qE as unsigned "
2259                                  "due to prototype", argnum, rname);
2260                       else
2261                         warning (0, "passing argument %d of %qE as signed "
2262                                  "due to prototype", argnum, rname);
2263                     }
2264                 }
2265
2266               parmval = convert_for_assignment (type, val, ic_argpass,
2267                                                 fundecl, function,
2268                                                 parmnum + 1);
2269
2270               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2271                   && INTEGRAL_TYPE_P (type)
2272                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2273                 parmval = default_conversion (parmval);
2274             }
2275           result = tree_cons (NULL_TREE, parmval, result);
2276         }
2277       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2278                && (TYPE_PRECISION (TREE_TYPE (val))
2279                    < TYPE_PRECISION (double_type_node)))
2280         /* Convert `float' to `double'.  */
2281         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2282       else if ((invalid_func_diag =
2283                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2284         {
2285           error (invalid_func_diag);
2286           return error_mark_node;
2287         }
2288       else
2289         /* Convert `short' and `char' to full-size `int'.  */
2290         result = tree_cons (NULL_TREE, default_conversion (val), result);
2291
2292       if (typetail)
2293         typetail = TREE_CHAIN (typetail);
2294     }
2295
2296   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2297     {
2298       error ("too few arguments to function %qE", function);
2299       return error_mark_node;
2300     }
2301
2302   return nreverse (result);
2303 }
2304 \f
2305 /* This is the entry point used by the parser to build unary operators
2306    in the input.  CODE, a tree_code, specifies the unary operator, and
2307    ARG is the operand.  For unary plus, the C parser currently uses
2308    CONVERT_EXPR for code.  */
2309
2310 struct c_expr
2311 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2312 {
2313   struct c_expr result;
2314
2315   result.original_code = ERROR_MARK;
2316   result.value = build_unary_op (code, arg.value, 0);
2317   overflow_warning (result.value);
2318   return result;
2319 }
2320
2321 /* This is the entry point used by the parser to build binary operators
2322    in the input.  CODE, a tree_code, specifies the binary operator, and
2323    ARG1 and ARG2 are the operands.  In addition to constructing the
2324    expression, we check for operands that were written with other binary
2325    operators in a way that is likely to confuse the user.  */
2326
2327 struct c_expr
2328 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2329                         struct c_expr arg2)
2330 {
2331   struct c_expr result;
2332
2333   enum tree_code code1 = arg1.original_code;
2334   enum tree_code code2 = arg2.original_code;
2335
2336   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2337   result.original_code = code;
2338
2339   if (TREE_CODE (result.value) == ERROR_MARK)
2340     return result;
2341
2342   /* Check for cases such as x+y<<z which users are likely
2343      to misinterpret.  */
2344   if (warn_parentheses)
2345     {
2346       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2347         {
2348           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2349               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2350             warning (0, "suggest parentheses around + or - inside shift");
2351         }
2352
2353       if (code == TRUTH_ORIF_EXPR)
2354         {
2355           if (code1 == TRUTH_ANDIF_EXPR
2356               || code2 == TRUTH_ANDIF_EXPR)
2357             warning (0, "suggest parentheses around && within ||");
2358         }
2359
2360       if (code == BIT_IOR_EXPR)
2361         {
2362           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2363               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2364               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2365               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2366             warning (0, "suggest parentheses around arithmetic in operand of |");
2367           /* Check cases like x|y==z */
2368           if (TREE_CODE_CLASS (code1) == tcc_comparison
2369               || TREE_CODE_CLASS (code2) == tcc_comparison)
2370             warning (0, "suggest parentheses around comparison in operand of |");
2371         }
2372
2373       if (code == BIT_XOR_EXPR)
2374         {
2375           if (code1 == BIT_AND_EXPR
2376               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2377               || code2 == BIT_AND_EXPR
2378               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2379             warning (0, "suggest parentheses around arithmetic in operand of ^");
2380           /* Check cases like x^y==z */
2381           if (TREE_CODE_CLASS (code1) == tcc_comparison
2382               || TREE_CODE_CLASS (code2) == tcc_comparison)
2383             warning (0, "suggest parentheses around comparison in operand of ^");
2384         }
2385
2386       if (code == BIT_AND_EXPR)
2387         {
2388           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2389               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2390             warning (0, "suggest parentheses around + or - in operand of &");
2391           /* Check cases like x&y==z */
2392           if (TREE_CODE_CLASS (code1) == tcc_comparison
2393               || TREE_CODE_CLASS (code2) == tcc_comparison)
2394             warning (0, "suggest parentheses around comparison in operand of &");
2395         }
2396       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2397       if (TREE_CODE_CLASS (code) == tcc_comparison
2398           && (TREE_CODE_CLASS (code1) == tcc_comparison
2399               || TREE_CODE_CLASS (code2) == tcc_comparison))
2400         warning (0, "comparisons like X<=Y<=Z do not have their mathematical meaning");
2401
2402     }
2403
2404   unsigned_conversion_warning (result.value, arg1.value);
2405   unsigned_conversion_warning (result.value, arg2.value);
2406   overflow_warning (result.value);
2407
2408   return result;
2409 }
2410 \f
2411 /* Return a tree for the difference of pointers OP0 and OP1.
2412    The resulting tree has type int.  */
2413
2414 static tree
2415 pointer_diff (tree op0, tree op1)
2416 {
2417   tree restype = ptrdiff_type_node;
2418
2419   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2420   tree con0, con1, lit0, lit1;
2421   tree orig_op1 = op1;
2422
2423   if (pedantic || warn_pointer_arith)
2424     {
2425       if (TREE_CODE (target_type) == VOID_TYPE)
2426         pedwarn ("pointer of type %<void *%> used in subtraction");
2427       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2428         pedwarn ("pointer to a function used in subtraction");
2429     }
2430
2431   /* If the conversion to ptrdiff_type does anything like widening or
2432      converting a partial to an integral mode, we get a convert_expression
2433      that is in the way to do any simplifications.
2434      (fold-const.c doesn't know that the extra bits won't be needed.
2435      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2436      different mode in place.)
2437      So first try to find a common term here 'by hand'; we want to cover
2438      at least the cases that occur in legal static initializers.  */
2439   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2440   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2441
2442   if (TREE_CODE (con0) == PLUS_EXPR)
2443     {
2444       lit0 = TREE_OPERAND (con0, 1);
2445       con0 = TREE_OPERAND (con0, 0);
2446     }
2447   else
2448     lit0 = integer_zero_node;
2449
2450   if (TREE_CODE (con1) == PLUS_EXPR)
2451     {
2452       lit1 = TREE_OPERAND (con1, 1);
2453       con1 = TREE_OPERAND (con1, 0);
2454     }
2455   else
2456     lit1 = integer_zero_node;
2457
2458   if (operand_equal_p (con0, con1, 0))
2459     {
2460       op0 = lit0;
2461       op1 = lit1;
2462     }
2463
2464
2465   /* First do the subtraction as integers;
2466      then drop through to build the divide operator.
2467      Do not do default conversions on the minus operator
2468      in case restype is a short type.  */
2469
2470   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2471                          convert (restype, op1), 0);
2472   /* This generates an error if op1 is pointer to incomplete type.  */
2473   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2474     error ("arithmetic on pointer to an incomplete type");
2475
2476   /* This generates an error if op0 is pointer to incomplete type.  */
2477   op1 = c_size_in_bytes (target_type);
2478
2479   /* Divide by the size, in easiest possible way.  */
2480   return fold (build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1)));
2481 }
2482 \f
2483 /* Construct and perhaps optimize a tree representation
2484    for a unary operation.  CODE, a tree_code, specifies the operation
2485    and XARG is the operand.
2486    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2487    the default promotions (such as from short to int).
2488    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2489    allows non-lvalues; this is only used to handle conversion of non-lvalue
2490    arrays to pointers in C99.  */
2491
2492 tree
2493 build_unary_op (enum tree_code code, tree xarg, int flag)
2494 {
2495   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2496   tree arg = xarg;
2497   tree argtype = 0;
2498   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2499   tree val;
2500   int noconvert = flag;
2501
2502   if (typecode == ERROR_MARK)
2503     return error_mark_node;
2504   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2505     typecode = INTEGER_TYPE;
2506
2507   switch (code)
2508     {
2509     case CONVERT_EXPR:
2510       /* This is used for unary plus, because a CONVERT_EXPR
2511          is enough to prevent anybody from looking inside for
2512          associativity, but won't generate any code.  */
2513       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2514             || typecode == COMPLEX_TYPE
2515             || typecode == VECTOR_TYPE))
2516         {
2517           error ("wrong type argument to unary plus");
2518           return error_mark_node;
2519         }
2520       else if (!noconvert)
2521         arg = default_conversion (arg);
2522       arg = non_lvalue (arg);
2523       break;
2524
2525     case NEGATE_EXPR:
2526       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2527             || typecode == COMPLEX_TYPE
2528             || typecode == VECTOR_TYPE))
2529         {
2530           error ("wrong type argument to unary minus");
2531           return error_mark_node;
2532         }
2533       else if (!noconvert)
2534         arg = default_conversion (arg);
2535       break;
2536
2537     case BIT_NOT_EXPR:
2538       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2539         {
2540           if (!noconvert)
2541             arg = default_conversion (arg);
2542         }
2543       else if (typecode == COMPLEX_TYPE)
2544         {
2545           code = CONJ_EXPR;
2546           if (pedantic)
2547             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2548           if (!noconvert)
2549             arg = default_conversion (arg);
2550         }
2551       else
2552         {
2553           error ("wrong type argument to bit-complement");
2554           return error_mark_node;
2555         }
2556       break;
2557
2558     case ABS_EXPR:
2559       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2560         {
2561           error ("wrong type argument to abs");
2562           return error_mark_node;
2563         }
2564       else if (!noconvert)
2565         arg = default_conversion (arg);
2566       break;
2567
2568     case CONJ_EXPR:
2569       /* Conjugating a real value is a no-op, but allow it anyway.  */
2570       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2571             || typecode == COMPLEX_TYPE))
2572         {
2573           error ("wrong type argument to conjugation");
2574           return error_mark_node;
2575         }
2576       else if (!noconvert)
2577         arg = default_conversion (arg);
2578       break;
2579
2580     case TRUTH_NOT_EXPR:
2581       if (typecode != INTEGER_TYPE
2582           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2583           && typecode != COMPLEX_TYPE)
2584         {
2585           error ("wrong type argument to unary exclamation mark");
2586           return error_mark_node;
2587         }
2588       arg = c_objc_common_truthvalue_conversion (arg);
2589       return invert_truthvalue (arg);
2590
2591     case NOP_EXPR:
2592       break;
2593
2594     case REALPART_EXPR:
2595       if (TREE_CODE (arg) == COMPLEX_CST)
2596         return TREE_REALPART (arg);
2597       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2598         return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2599       else
2600         return arg;
2601
2602     case IMAGPART_EXPR:
2603       if (TREE_CODE (arg) == COMPLEX_CST)
2604         return TREE_IMAGPART (arg);
2605       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2606         return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2607       else
2608         return convert (TREE_TYPE (arg), integer_zero_node);
2609
2610     case PREINCREMENT_EXPR:
2611     case POSTINCREMENT_EXPR:
2612     case PREDECREMENT_EXPR:
2613     case POSTDECREMENT_EXPR:
2614
2615       /* Increment or decrement the real part of the value,
2616          and don't change the imaginary part.  */
2617       if (typecode == COMPLEX_TYPE)
2618         {
2619           tree real, imag;
2620
2621           if (pedantic)
2622             pedwarn ("ISO C does not support %<++%> and %<--%>"
2623                      " on complex types");
2624
2625           arg = stabilize_reference (arg);
2626           real = build_unary_op (REALPART_EXPR, arg, 1);
2627           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2628           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2629                          build_unary_op (code, real, 1), imag);
2630         }
2631
2632       /* Report invalid types.  */
2633
2634       if (typecode != POINTER_TYPE
2635           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2636         {
2637           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2638             error ("wrong type argument to increment");
2639           else
2640             error ("wrong type argument to decrement");
2641
2642           return error_mark_node;
2643         }
2644
2645       {
2646         tree inc;
2647         tree result_type = TREE_TYPE (arg);
2648
2649         arg = get_unwidened (arg, 0);
2650         argtype = TREE_TYPE (arg);
2651
2652         /* Compute the increment.  */
2653
2654         if (typecode == POINTER_TYPE)
2655           {
2656             /* If pointer target is an undefined struct,
2657                we just cannot know how to do the arithmetic.  */
2658             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2659               {
2660                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2661                   error ("increment of pointer to unknown structure");
2662                 else
2663                   error ("decrement of pointer to unknown structure");
2664               }
2665             else if ((pedantic || warn_pointer_arith)
2666                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2667                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2668               {
2669                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2670                   pedwarn ("wrong type argument to increment");
2671                 else
2672                   pedwarn ("wrong type argument to decrement");
2673               }
2674
2675             inc = c_size_in_bytes (TREE_TYPE (result_type));
2676           }
2677         else
2678           inc = integer_one_node;
2679
2680         inc = convert (argtype, inc);
2681
2682         /* Complain about anything else that is not a true lvalue.  */
2683         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2684                                     || code == POSTINCREMENT_EXPR)
2685                                    ? lv_increment
2686                                    : lv_decrement)))
2687           return error_mark_node;
2688
2689         /* Report a read-only lvalue.  */
2690         if (TREE_READONLY (arg))
2691           readonly_error (arg,
2692                           ((code == PREINCREMENT_EXPR
2693                             || code == POSTINCREMENT_EXPR)
2694                            ? lv_increment : lv_decrement));
2695
2696         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2697           val = boolean_increment (code, arg);
2698         else
2699           val = build2 (code, TREE_TYPE (arg), arg, inc);
2700         TREE_SIDE_EFFECTS (val) = 1;
2701         val = convert (result_type, val);
2702         if (TREE_CODE (val) != code)
2703           TREE_NO_WARNING (val) = 1;
2704         return val;
2705       }
2706
2707     case ADDR_EXPR:
2708       /* Note that this operation never does default_conversion.  */
2709
2710       /* Let &* cancel out to simplify resulting code.  */
2711       if (TREE_CODE (arg) == INDIRECT_REF)
2712         {
2713           /* Don't let this be an lvalue.  */
2714           if (lvalue_p (TREE_OPERAND (arg, 0)))
2715             return non_lvalue (TREE_OPERAND (arg, 0));
2716           return TREE_OPERAND (arg, 0);
2717         }
2718
2719       /* For &x[y], return x+y */
2720       if (TREE_CODE (arg) == ARRAY_REF)
2721         {
2722           if (!c_mark_addressable (TREE_OPERAND (arg, 0)))
2723             return error_mark_node;
2724           return build_binary_op (PLUS_EXPR,
2725                                   default_function_array_conversion
2726                                     (TREE_OPERAND (arg, 0)),
2727                                   TREE_OPERAND (arg, 1), 1);
2728         }
2729
2730       /* Anything not already handled and not a true memory reference
2731          or a non-lvalue array is an error.  */
2732       else if (typecode != FUNCTION_TYPE && !flag
2733                && !lvalue_or_else (arg, lv_addressof))
2734         return error_mark_node;
2735
2736       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2737       argtype = TREE_TYPE (arg);
2738
2739       /* If the lvalue is const or volatile, merge that into the type
2740          to which the address will point.  Note that you can't get a
2741          restricted pointer by taking the address of something, so we
2742          only have to deal with `const' and `volatile' here.  */
2743       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2744           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2745           argtype = c_build_type_variant (argtype,
2746                                           TREE_READONLY (arg),
2747                                           TREE_THIS_VOLATILE (arg));
2748
2749       if (!c_mark_addressable (arg))
2750         return error_mark_node;
2751
2752       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2753                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2754
2755       argtype = build_pointer_type (argtype);
2756
2757       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2758          when we have proper support for integer constant expressions.  */
2759       val = get_base_address (arg);
2760       if (val && TREE_CODE (val) == INDIRECT_REF
2761           && integer_zerop (TREE_OPERAND (val, 0)))
2762         return fold_convert (argtype, fold_offsetof (arg));
2763
2764       val = build1 (ADDR_EXPR, argtype, arg);
2765
2766       if (TREE_CODE (arg) == COMPOUND_LITERAL_EXPR)
2767         TREE_INVARIANT (val) = TREE_CONSTANT (val) = 1;
2768
2769       return val;
2770
2771     default:
2772       break;
2773     }
2774
2775   if (argtype == 0)
2776     argtype = TREE_TYPE (arg);
2777   val = build1 (code, argtype, arg);
2778   return require_constant_value ? fold_initializer (val) : fold (val);
2779 }
2780
2781 /* Return nonzero if REF is an lvalue valid for this language.
2782    Lvalues can be assigned, unless their type has TYPE_READONLY.
2783    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2784
2785 static int
2786 lvalue_p (tree ref)
2787 {
2788   enum tree_code code = TREE_CODE (ref);
2789
2790   switch (code)
2791     {
2792     case REALPART_EXPR:
2793     case IMAGPART_EXPR:
2794     case COMPONENT_REF:
2795       return lvalue_p (TREE_OPERAND (ref, 0));
2796
2797     case COMPOUND_LITERAL_EXPR:
2798     case STRING_CST:
2799       return 1;
2800
2801     case INDIRECT_REF:
2802     case ARRAY_REF:
2803     case VAR_DECL:
2804     case PARM_DECL:
2805     case RESULT_DECL:
2806     case ERROR_MARK:
2807       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2808               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2809
2810     case BIND_EXPR:
2811       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2812
2813     default:
2814       return 0;
2815     }
2816 }
2817 \f
2818 /* Give an error for storing in something that is 'const'.  */
2819
2820 static void
2821 readonly_error (tree arg, enum lvalue_use use)
2822 {
2823   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement);
2824   /* Using this macro rather than (for example) arrays of messages
2825      ensures that all the format strings are checked at compile
2826      time.  */
2827 #define READONLY_MSG(A, I, D) (use == lv_assign                         \
2828                                ? (A)                                    \
2829                                : (use == lv_increment ? (I) : (D)))
2830   if (TREE_CODE (arg) == COMPONENT_REF)
2831     {
2832       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2833         readonly_error (TREE_OPERAND (arg, 0), use);
2834       else
2835         error (READONLY_MSG (G_("assignment of read-only member %qD"),
2836                              G_("increment of read-only member %qD"),
2837                              G_("decrement of read-only member %qD")),
2838                TREE_OPERAND (arg, 1));
2839     }
2840   else if (TREE_CODE (arg) == VAR_DECL)
2841     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
2842                          G_("increment of read-only variable %qD"),
2843                          G_("decrement of read-only variable %qD")),
2844            arg);
2845   else
2846     error (READONLY_MSG (G_("assignment of read-only location"),
2847                          G_("increment of read-only location"),
2848                          G_("decrement of read-only location")));
2849 }
2850
2851
2852 /* Return nonzero if REF is an lvalue valid for this language;
2853    otherwise, print an error message and return zero.  USE says
2854    how the lvalue is being used and so selects the error message.  */
2855
2856 static int
2857 lvalue_or_else (tree ref, enum lvalue_use use)
2858 {
2859   int win = lvalue_p (ref);
2860
2861   if (!win)
2862     lvalue_error (use);
2863
2864   return win;
2865 }
2866 \f
2867 /* Mark EXP saying that we need to be able to take the
2868    address of it; it should not be allocated in a register.
2869    Returns true if successful.  */
2870
2871 bool
2872 c_mark_addressable (tree exp)
2873 {
2874   tree x = exp;
2875
2876   while (1)
2877     switch (TREE_CODE (x))
2878       {
2879       case COMPONENT_REF:
2880         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2881           {
2882             error
2883               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
2884             return false;
2885           }
2886
2887         /* ... fall through ...  */
2888
2889       case ADDR_EXPR:
2890       case ARRAY_REF:
2891       case REALPART_EXPR:
2892       case IMAGPART_EXPR:
2893         x = TREE_OPERAND (x, 0);
2894         break;
2895
2896       case COMPOUND_LITERAL_EXPR:
2897       case CONSTRUCTOR:
2898         TREE_ADDRESSABLE (x) = 1;
2899         return true;
2900
2901       case VAR_DECL:
2902       case CONST_DECL:
2903       case PARM_DECL:
2904       case RESULT_DECL:
2905         if (C_DECL_REGISTER (x)
2906             && DECL_NONLOCAL (x))
2907           {
2908             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2909               {
2910                 error
2911                   ("global register variable %qD used in nested function", x);
2912                 return false;
2913               }
2914             pedwarn ("register variable %qD used in nested function", x);
2915           }
2916         else if (C_DECL_REGISTER (x))
2917           {
2918             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2919               error ("address of global register variable %qD requested", x);
2920             else
2921               error ("address of register variable %qD requested", x);
2922             return false;
2923           }
2924
2925         /* drops in */
2926       case FUNCTION_DECL:
2927         TREE_ADDRESSABLE (x) = 1;
2928         /* drops out */
2929       default:
2930         return true;
2931     }
2932 }
2933 \f
2934 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2935
2936 tree
2937 build_conditional_expr (tree ifexp, tree op1, tree op2)
2938 {
2939   tree type1;
2940   tree type2;
2941   enum tree_code code1;
2942   enum tree_code code2;
2943   tree result_type = NULL;
2944   tree orig_op1 = op1, orig_op2 = op2;
2945
2946   /* Promote both alternatives.  */
2947
2948   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
2949     op1 = default_conversion (op1);
2950   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
2951     op2 = default_conversion (op2);
2952
2953   if (TREE_CODE (ifexp) == ERROR_MARK
2954       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
2955       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
2956     return error_mark_node;
2957
2958   type1 = TREE_TYPE (op1);
2959   code1 = TREE_CODE (type1);
2960   type2 = TREE_TYPE (op2);
2961   code2 = TREE_CODE (type2);
2962
2963   /* C90 does not permit non-lvalue arrays in conditional expressions.
2964      In C99 they will be pointers by now.  */
2965   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
2966     {
2967       error ("non-lvalue array in conditional expression");
2968       return error_mark_node;
2969     }
2970
2971   /* Quickly detect the usual case where op1 and op2 have the same type
2972      after promotion.  */
2973   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
2974     {
2975       if (type1 == type2)
2976         result_type = type1;
2977       else
2978         result_type = TYPE_MAIN_VARIANT (type1);
2979     }
2980   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
2981             || code1 == COMPLEX_TYPE)
2982            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
2983                || code2 == COMPLEX_TYPE))
2984     {
2985       result_type = c_common_type (type1, type2);
2986
2987       /* If -Wsign-compare, warn here if type1 and type2 have
2988          different signedness.  We'll promote the signed to unsigned
2989          and later code won't know it used to be different.
2990          Do this check on the original types, so that explicit casts
2991          will be considered, but default promotions won't.  */
2992       if (warn_sign_compare && !skip_evaluation)
2993         {
2994           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
2995           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
2996
2997           if (unsigned_op1 ^ unsigned_op2)
2998             {
2999               /* Do not warn if the result type is signed, since the
3000                  signed type will only be chosen if it can represent
3001                  all the values of the unsigned type.  */
3002               if (!TYPE_UNSIGNED (result_type))
3003                 /* OK */;
3004               /* Do not warn if the signed quantity is an unsuffixed
3005                  integer literal (or some static constant expression
3006                  involving such literals) and it is non-negative.  */
3007               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3008                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3009                 /* OK */;
3010               else
3011                 warning (0, "signed and unsigned type in conditional expression");
3012             }
3013         }
3014     }
3015   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3016     {
3017       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3018         pedwarn ("ISO C forbids conditional expr with only one void side");
3019       result_type = void_type_node;
3020     }
3021   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3022     {
3023       if (comp_target_types (type1, type2))
3024         result_type = common_pointer_type (type1, type2);
3025       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3026                && TREE_CODE (orig_op1) != NOP_EXPR)
3027         result_type = qualify_type (type2, type1);
3028       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3029                && TREE_CODE (orig_op2) != NOP_EXPR)
3030         result_type = qualify_type (type1, type2);
3031       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3032         {
3033           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3034             pedwarn ("ISO C forbids conditional expr between "
3035                      "%<void *%> and function pointer");
3036           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3037                                                           TREE_TYPE (type2)));
3038         }
3039       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3040         {
3041           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3042             pedwarn ("ISO C forbids conditional expr between "
3043                      "%<void *%> and function pointer");
3044           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3045                                                           TREE_TYPE (type1)));
3046         }
3047       else
3048         {
3049           pedwarn ("pointer type mismatch in conditional expression");
3050           result_type = build_pointer_type (void_type_node);
3051         }
3052     }
3053   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3054     {
3055       if (!integer_zerop (op2))
3056         pedwarn ("pointer/integer type mismatch in conditional expression");
3057       else
3058         {
3059           op2 = null_pointer_node;
3060         }
3061       result_type = type1;
3062     }
3063   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3064     {
3065       if (!integer_zerop (op1))
3066         pedwarn ("pointer/integer type mismatch in conditional expression");
3067       else
3068         {
3069           op1 = null_pointer_node;
3070         }
3071       result_type = type2;
3072     }
3073
3074   if (!result_type)
3075     {
3076       if (flag_cond_mismatch)
3077         result_type = void_type_node;
3078       else
3079         {
3080           error ("type mismatch in conditional expression");
3081           return error_mark_node;
3082         }
3083     }
3084
3085   /* Merge const and volatile flags of the incoming types.  */
3086   result_type
3087     = build_type_variant (result_type,
3088                           TREE_READONLY (op1) || TREE_READONLY (op2),
3089                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3090
3091   if (result_type != TREE_TYPE (op1))
3092     op1 = convert_and_check (result_type, op1);
3093   if (result_type != TREE_TYPE (op2))
3094     op2 = convert_and_check (result_type, op2);
3095
3096   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3097 }
3098 \f
3099 /* Return a compound expression that performs two expressions and
3100    returns the value of the second of them.  */
3101
3102 tree
3103 build_compound_expr (tree expr1, tree expr2)
3104 {
3105   if (!TREE_SIDE_EFFECTS (expr1))
3106     {
3107       /* The left-hand operand of a comma expression is like an expression
3108          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3109          any side-effects, unless it was explicitly cast to (void).  */
3110       if (warn_unused_value)
3111         {
3112           if (VOID_TYPE_P (TREE_TYPE (expr1))
3113               && TREE_CODE (expr1) == CONVERT_EXPR)
3114             ; /* (void) a, b */
3115           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3116                    && TREE_CODE (expr1) == COMPOUND_EXPR
3117                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3118             ; /* (void) a, (void) b, c */
3119           else
3120             warning (0, "left-hand operand of comma expression has no effect");
3121         }
3122     }
3123
3124   /* With -Wunused, we should also warn if the left-hand operand does have
3125      side-effects, but computes a value which is not used.  For example, in
3126      `foo() + bar(), baz()' the result of the `+' operator is not used,
3127      so we should issue a warning.  */
3128   else if (warn_unused_value)
3129     warn_if_unused_value (expr1, input_location);
3130
3131   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3132 }
3133
3134 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3135
3136 tree
3137 build_c_cast (tree type, tree expr)
3138 {
3139   tree value = expr;
3140
3141   if (type == error_mark_node || expr == error_mark_node)
3142     return error_mark_node;
3143
3144   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3145      only in <protocol> qualifications.  But when constructing cast expressions,
3146      the protocols do matter and must be kept around.  */
3147   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3148     return build1 (NOP_EXPR, type, expr);
3149
3150   type = TYPE_MAIN_VARIANT (type);
3151
3152   if (TREE_CODE (type) == ARRAY_TYPE)
3153     {
3154       error ("cast specifies array type");
3155       return error_mark_node;
3156     }
3157
3158   if (TREE_CODE (type) == FUNCTION_TYPE)
3159     {
3160       error ("cast specifies function type");
3161       return error_mark_node;
3162     }
3163
3164   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3165     {
3166       if (pedantic)
3167         {
3168           if (TREE_CODE (type) == RECORD_TYPE
3169               || TREE_CODE (type) == UNION_TYPE)
3170             pedwarn ("ISO C forbids casting nonscalar to the same type");
3171         }
3172     }
3173   else if (TREE_CODE (type) == UNION_TYPE)
3174     {
3175       tree field;
3176
3177       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3178         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3179                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3180           break;
3181
3182       if (field)
3183         {
3184           tree t;
3185
3186           if (pedantic)
3187             pedwarn ("ISO C forbids casts to union type");
3188           t = digest_init (type,
3189                            build_constructor (type,
3190                                               build_tree_list (field, value)),
3191                            true, 0);
3192           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3193           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3194           return t;
3195         }
3196       error ("cast to union type from type not present in union");
3197       return error_mark_node;
3198     }
3199   else
3200     {
3201       tree otype, ovalue;
3202
3203       if (type == void_type_node)
3204         return build1 (CONVERT_EXPR, type, value);
3205
3206       otype = TREE_TYPE (value);
3207
3208       /* Optionally warn about potentially worrisome casts.  */
3209
3210       if (warn_cast_qual
3211           && TREE_CODE (type) == POINTER_TYPE
3212           && TREE_CODE (otype) == POINTER_TYPE)
3213         {
3214           tree in_type = type;
3215           tree in_otype = otype;
3216           int added = 0;
3217           int discarded = 0;
3218
3219           /* Check that the qualifiers on IN_TYPE are a superset of
3220              the qualifiers of IN_OTYPE.  The outermost level of
3221              POINTER_TYPE nodes is uninteresting and we stop as soon
3222              as we hit a non-POINTER_TYPE node on either type.  */
3223           do
3224             {
3225               in_otype = TREE_TYPE (in_otype);
3226               in_type = TREE_TYPE (in_type);
3227
3228               /* GNU C allows cv-qualified function types.  'const'
3229                  means the function is very pure, 'volatile' means it
3230                  can't return.  We need to warn when such qualifiers
3231                  are added, not when they're taken away.  */
3232               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3233                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3234                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3235               else
3236                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3237             }
3238           while (TREE_CODE (in_type) == POINTER_TYPE
3239                  && TREE_CODE (in_otype) == POINTER_TYPE);
3240
3241           if (added)
3242             warning (0, "cast adds new qualifiers to function type");
3243
3244           if (discarded)
3245             /* There are qualifiers present in IN_OTYPE that are not
3246                present in IN_TYPE.  */
3247             warning (0, "cast discards qualifiers from pointer target type");
3248         }
3249
3250       /* Warn about possible alignment problems.  */
3251       if (STRICT_ALIGNMENT && warn_cast_align
3252           && TREE_CODE (type) == POINTER_TYPE
3253           && TREE_CODE (otype) == POINTER_TYPE
3254           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3255           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3256           /* Don't warn about opaque types, where the actual alignment
3257              restriction is unknown.  */
3258           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3259                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3260                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3261           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3262         warning (0, "cast increases required alignment of target type");
3263
3264       if (warn_pointer_to_int_cast
3265           && TREE_CODE (type) == INTEGER_TYPE
3266           && TREE_CODE (otype) == POINTER_TYPE
3267           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3268           && !TREE_CONSTANT (value))
3269         warning (0, "cast from pointer to integer of different size");
3270
3271       if (warn_bad_function_cast
3272           && TREE_CODE (value) == CALL_EXPR
3273           && TREE_CODE (type) != TREE_CODE (otype))
3274         warning (0, "cast from function call of type %qT to non-matching "
3275                  "type %qT", otype, type);
3276
3277       if (warn_int_to_pointer_cast
3278           && TREE_CODE (type) == POINTER_TYPE
3279           && TREE_CODE (otype) == INTEGER_TYPE
3280           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3281           /* Don't warn about converting any constant.  */
3282           && !TREE_CONSTANT (value))
3283         warning (0, "cast to pointer from integer of different size");
3284
3285       if (flag_strict_aliasing && warn_strict_aliasing
3286           && TREE_CODE (type) == POINTER_TYPE
3287           && TREE_CODE (otype) == POINTER_TYPE
3288           && TREE_CODE (expr) == ADDR_EXPR
3289           && (DECL_P (TREE_OPERAND (expr, 0))
3290               || TREE_CODE (TREE_OPERAND (expr, 0)) == COMPONENT_REF)
3291           && !VOID_TYPE_P (TREE_TYPE (type)))
3292         {
3293           /* Casting the address of an object to non void pointer. Warn
3294              if the cast breaks type based aliasing.  */
3295           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3296             warning (0, "type-punning to incomplete type might break strict-aliasing rules");
3297           else
3298             {
3299               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3300               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3301
3302               if (!alias_sets_conflict_p (set1, set2))
3303                 warning (0, "dereferencing type-punned pointer will break strict-aliasing rules");
3304               else if (warn_strict_aliasing > 1
3305                        && !alias_sets_might_conflict_p (set1, set2))
3306                 warning (0, "dereferencing type-punned pointer might break strict-aliasing rules");
3307             }
3308         }
3309
3310       /* If pedantic, warn for conversions between function and object
3311          pointer types, except for converting a null pointer constant
3312          to function pointer type.  */
3313       if (pedantic
3314           && TREE_CODE (type) == POINTER_TYPE
3315           && TREE_CODE (otype) == POINTER_TYPE
3316           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3317           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3318         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3319
3320       if (pedantic
3321           && TREE_CODE (type) == POINTER_TYPE
3322           && TREE_CODE (otype) == POINTER_TYPE
3323           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3324           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3325           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3326                && TREE_CODE (expr) != NOP_EXPR))
3327         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3328
3329       ovalue = value;
3330       value = convert (type, value);
3331
3332       /* Ignore any integer overflow caused by the cast.  */
3333       if (TREE_CODE (value) == INTEGER_CST)
3334         {
3335           /* If OVALUE had overflow set, then so will VALUE, so it
3336              is safe to overwrite.  */
3337           if (CONSTANT_CLASS_P (ovalue))
3338             {
3339               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3340               /* Similarly, constant_overflow cannot have become cleared.  */
3341               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3342             }
3343           else
3344             TREE_OVERFLOW (value) = 0;
3345         }
3346     }
3347
3348   /* Don't let a cast be an lvalue.  */
3349   if (value == expr)
3350     value = non_lvalue (value);
3351
3352   return value;
3353 }
3354
3355 /* Interpret a cast of expression EXPR to type TYPE.  */
3356 tree
3357 c_cast_expr (struct c_type_name *type_name, tree expr)
3358 {
3359   tree type;
3360   int saved_wsp = warn_strict_prototypes;
3361
3362   /* This avoids warnings about unprototyped casts on
3363      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3364   if (TREE_CODE (expr) == INTEGER_CST)
3365     warn_strict_prototypes = 0;
3366   type = groktypename (type_name);
3367   warn_strict_prototypes = saved_wsp;
3368
3369   return build_c_cast (type, expr);
3370 }
3371
3372 \f
3373 /* Build an assignment expression of lvalue LHS from value RHS.
3374    MODIFYCODE is the code for a binary operator that we use
3375    to combine the old value of LHS with RHS to get the new value.
3376    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3377
3378 tree
3379 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3380 {
3381   tree result;
3382   tree newrhs;
3383   tree lhstype = TREE_TYPE (lhs);
3384   tree olhstype = lhstype;
3385
3386   /* Types that aren't fully specified cannot be used in assignments.  */
3387   lhs = require_complete_type (lhs);
3388
3389   /* Avoid duplicate error messages from operands that had errors.  */
3390   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3391     return error_mark_node;
3392
3393   STRIP_TYPE_NOPS (rhs);
3394
3395   newrhs = rhs;
3396
3397   /* If a binary op has been requested, combine the old LHS value with the RHS
3398      producing the value we should actually store into the LHS.  */
3399
3400   if (modifycode != NOP_EXPR)
3401     {
3402       lhs = stabilize_reference (lhs);
3403       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3404     }
3405
3406   if (!lvalue_or_else (lhs, lv_assign))
3407     return error_mark_node;
3408
3409   /* Give an error for storing in something that is 'const'.  */
3410
3411   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3412       || ((TREE_CODE (lhstype) == RECORD_TYPE
3413            || TREE_CODE (lhstype) == UNION_TYPE)
3414           && C_TYPE_FIELDS_READONLY (lhstype)))
3415     readonly_error (lhs, lv_assign);
3416
3417   /* If storing into a structure or union member,
3418      it has probably been given type `int'.
3419      Compute the type that would go with
3420      the actual amount of storage the member occupies.  */
3421
3422   if (TREE_CODE (lhs) == COMPONENT_REF
3423       && (TREE_CODE (lhstype) == INTEGER_TYPE
3424           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3425           || TREE_CODE (lhstype) == REAL_TYPE
3426           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3427     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3428
3429   /* If storing in a field that is in actuality a short or narrower than one,
3430      we must store in the field in its actual type.  */
3431
3432   if (lhstype != TREE_TYPE (lhs))
3433     {
3434       lhs = copy_node (lhs);
3435       TREE_TYPE (lhs) = lhstype;
3436     }
3437
3438   /* Convert new value to destination type.  */
3439
3440   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3441                                    NULL_TREE, NULL_TREE, 0);
3442   if (TREE_CODE (newrhs) == ERROR_MARK)
3443     return error_mark_node;
3444
3445   /* Emit ObjC write barrier, if necessary.  */
3446   if (c_dialect_objc () && flag_objc_gc)
3447     {
3448       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3449       if (result)
3450         return result;
3451     }
3452
3453   /* Scan operands.  */
3454
3455   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3456   TREE_SIDE_EFFECTS (result) = 1;
3457
3458   /* If we got the LHS in a different type for storing in,
3459      convert the result back to the nominal type of LHS
3460      so that the value we return always has the same type
3461      as the LHS argument.  */
3462
3463   if (olhstype == TREE_TYPE (result))
3464     return result;
3465   return convert_for_assignment (olhstype, result, ic_assign,
3466                                  NULL_TREE, NULL_TREE, 0);
3467 }
3468 \f
3469 /* Convert value RHS to type TYPE as preparation for an assignment
3470    to an lvalue of type TYPE.
3471    The real work of conversion is done by `convert'.
3472    The purpose of this function is to generate error messages
3473    for assignments that are not allowed in C.
3474    ERRTYPE says whether it is argument passing, assignment,
3475    initialization or return.
3476
3477    FUNCTION is a tree for the function being called.
3478    PARMNUM is the number of the argument, for printing in error messages.  */
3479
3480 static tree
3481 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3482                         tree fundecl, tree function, int parmnum)
3483 {
3484   enum tree_code codel = TREE_CODE (type);
3485   tree rhstype;
3486   enum tree_code coder;
3487   tree rname = NULL_TREE;
3488   bool objc_ok = false;
3489
3490   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3491     {
3492       tree selector;
3493       /* Change pointer to function to the function itself for
3494          diagnostics.  */
3495       if (TREE_CODE (function) == ADDR_EXPR
3496           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3497         function = TREE_OPERAND (function, 0);
3498
3499       /* Handle an ObjC selector specially for diagnostics.  */
3500       selector = objc_message_selector ();
3501       rname = function;
3502       if (selector && parmnum > 2)
3503         {
3504           rname = selector;
3505           parmnum -= 2;
3506         }
3507     }
3508
3509   /* This macro is used to emit diagnostics to ensure that all format
3510      strings are complete sentences, visible to gettext and checked at
3511      compile time.  */
3512 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3513   do {                                          \
3514     switch (errtype)                            \
3515       {                                         \
3516       case ic_argpass:                          \
3517         pedwarn (AR, parmnum, rname);           \
3518         break;                                  \
3519       case ic_argpass_nonproto:                 \
3520         warning (0, AR, parmnum, rname);                \
3521         break;                                  \
3522       case ic_assign:                           \
3523         pedwarn (AS);                           \
3524         break;                                  \
3525       case ic_init:                             \
3526         pedwarn (IN);                           \
3527         break;                                  \
3528       case ic_return:                           \
3529         pedwarn (RE);                           \
3530         break;                                  \
3531       default:                                  \
3532         gcc_unreachable ();                     \
3533       }                                         \
3534   } while (0)
3535
3536   STRIP_TYPE_NOPS (rhs);
3537
3538   if (optimize && TREE_CODE (rhs) == VAR_DECL
3539            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3540     rhs = decl_constant_value_for_broken_optimization (rhs);
3541
3542   rhstype = TREE_TYPE (rhs);
3543   coder = TREE_CODE (rhstype);
3544
3545   if (coder == ERROR_MARK)
3546     return error_mark_node;
3547
3548   if (c_dialect_objc ())
3549     {
3550       int parmno;
3551
3552       switch (errtype)
3553         {
3554         case ic_return:
3555           parmno = 0;
3556           break;
3557
3558         case ic_assign:
3559           parmno = -1;
3560           break;
3561
3562         case ic_init:
3563           parmno = -2;
3564           break;
3565
3566         default:
3567           parmno = parmnum;
3568           break;
3569         }
3570
3571       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3572     }
3573
3574   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3575     {
3576       overflow_warning (rhs);
3577       return rhs;
3578     }
3579
3580   if (coder == VOID_TYPE)
3581     {
3582       /* Except for passing an argument to an unprototyped function,
3583          this is a constraint violation.  When passing an argument to
3584          an unprototyped function, it is compile-time undefined;
3585          making it a constraint in that case was rejected in
3586          DR#252.  */
3587       error ("void value not ignored as it ought to be");
3588       return error_mark_node;
3589     }
3590   /* A type converts to a reference to it.
3591      This code doesn't fully support references, it's just for the
3592      special case of va_start and va_copy.  */
3593   if (codel == REFERENCE_TYPE
3594       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3595     {
3596       if (!lvalue_p (rhs))
3597         {
3598           error ("cannot pass rvalue to reference parameter");
3599           return error_mark_node;
3600         }
3601       if (!c_mark_addressable (rhs))
3602         return error_mark_node;
3603       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3604
3605       /* We already know that these two types are compatible, but they
3606          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3607          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3608          likely to be va_list, a typedef to __builtin_va_list, which
3609          is different enough that it will cause problems later.  */
3610       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3611         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3612
3613       rhs = build1 (NOP_EXPR, type, rhs);
3614       return rhs;
3615     }
3616   /* Some types can interconvert without explicit casts.  */
3617   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3618            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3619     return convert (type, rhs);
3620   /* Arithmetic types all interconvert, and enum is treated like int.  */
3621   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3622             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3623             || codel == BOOLEAN_TYPE)
3624            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3625                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3626                || coder == BOOLEAN_TYPE))
3627     return convert_and_check (type, rhs);
3628
3629   /* Conversion to a transparent union from its member types.
3630      This applies only to function arguments.  */
3631   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3632            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3633     {
3634       tree memb_types;
3635       tree marginal_memb_type = 0;
3636
3637       for (memb_types = TYPE_FIELDS (type); memb_types;
3638            memb_types = TREE_CHAIN (memb_types))
3639         {
3640           tree memb_type = TREE_TYPE (memb_types);
3641
3642           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3643                          TYPE_MAIN_VARIANT (rhstype)))
3644             break;
3645
3646           if (TREE_CODE (memb_type) != POINTER_TYPE)
3647             continue;
3648
3649           if (coder == POINTER_TYPE)
3650             {
3651               tree ttl = TREE_TYPE (memb_type);
3652               tree ttr = TREE_TYPE (rhstype);
3653
3654               /* Any non-function converts to a [const][volatile] void *
3655                  and vice versa; otherwise, targets must be the same.
3656                  Meanwhile, the lhs target must have all the qualifiers of
3657                  the rhs.  */
3658               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3659                   || comp_target_types (memb_type, rhstype))
3660                 {
3661                   /* If this type won't generate any warnings, use it.  */
3662                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3663                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3664                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3665                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3666                              == TYPE_QUALS (ttr))
3667                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3668                              == TYPE_QUALS (ttl))))
3669                     break;
3670
3671                   /* Keep looking for a better type, but remember this one.  */
3672                   if (!marginal_memb_type)
3673                     marginal_memb_type = memb_type;
3674                 }
3675             }
3676
3677           /* Can convert integer zero to any pointer type.  */
3678           if (integer_zerop (rhs)
3679               || (TREE_CODE (rhs) == NOP_EXPR
3680                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3681             {
3682               rhs = null_pointer_node;
3683               break;
3684             }
3685         }
3686
3687       if (memb_types || marginal_memb_type)
3688         {
3689           if (!memb_types)
3690             {
3691               /* We have only a marginally acceptable member type;
3692                  it needs a warning.  */
3693               tree ttl = TREE_TYPE (marginal_memb_type);
3694               tree ttr = TREE_TYPE (rhstype);
3695
3696               /* Const and volatile mean something different for function
3697                  types, so the usual warnings are not appropriate.  */
3698               if (TREE_CODE (ttr) == FUNCTION_TYPE
3699                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3700                 {
3701                   /* Because const and volatile on functions are
3702                      restrictions that say the function will not do
3703                      certain things, it is okay to use a const or volatile
3704                      function where an ordinary one is wanted, but not
3705                      vice-versa.  */
3706                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3707                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3708                                             "makes qualified function "
3709                                             "pointer from unqualified"),
3710                                          G_("assignment makes qualified "
3711                                             "function pointer from "
3712                                             "unqualified"),
3713                                          G_("initialization makes qualified "
3714                                             "function pointer from "
3715                                             "unqualified"),
3716                                          G_("return makes qualified function "
3717                                             "pointer from unqualified"));
3718                 }
3719               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3720                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3721                                         "qualifiers from pointer target type"),
3722                                      G_("assignment discards qualifiers "
3723                                         "from pointer target type"),
3724                                      G_("initialization discards qualifiers "
3725                                         "from pointer target type"),
3726                                      G_("return discards qualifiers from "
3727                                         "pointer target type"));
3728             }
3729
3730           if (pedantic && !DECL_IN_SYSTEM_HEADER (fundecl))
3731             pedwarn ("ISO C prohibits argument conversion to union type");
3732
3733           return build1 (NOP_EXPR, type, rhs);
3734         }
3735     }
3736
3737   /* Conversions among pointers */
3738   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3739            && (coder == codel))
3740     {
3741       tree ttl = TREE_TYPE (type);
3742       tree ttr = TREE_TYPE (rhstype);
3743       tree mvl = ttl;
3744       tree mvr = ttr;
3745       bool is_opaque_pointer;
3746       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3747
3748       if (TREE_CODE (mvl) != ARRAY_TYPE)
3749         mvl = TYPE_MAIN_VARIANT (mvl);
3750       if (TREE_CODE (mvr) != ARRAY_TYPE)
3751         mvr = TYPE_MAIN_VARIANT (mvr);
3752       /* Opaque pointers are treated like void pointers.  */
3753       is_opaque_pointer = (targetm.vector_opaque_p (type)
3754                            || targetm.vector_opaque_p (rhstype))
3755         && TREE_CODE (ttl) == VECTOR_TYPE
3756         && TREE_CODE (ttr) == VECTOR_TYPE;
3757
3758       /* C++ does not allow the implicit conversion void* -> T*.  However,
3759          for the purpose of reducing the number of false positives, we
3760          tolerate the special case of
3761
3762                 int *p = NULL;
3763
3764          where NULL is typically defined in C to be '(void *) 0'.  */
3765       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3766         warning (OPT_Wc___compat, "request for implicit conversion from "
3767                  "%qT to %qT not permitted in C++", rhstype, type);
3768
3769       /* Any non-function converts to a [const][volatile] void *
3770          and vice versa; otherwise, targets must be the same.
3771          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3772       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3773           || (target_cmp = comp_target_types (type, rhstype))
3774           || is_opaque_pointer
3775           || (c_common_unsigned_type (mvl)
3776               == c_common_unsigned_type (mvr)))
3777         {
3778           if (pedantic
3779               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3780                   ||
3781                   (VOID_TYPE_P (ttr)
3782                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3783                       which are not ANSI null ptr constants.  */
3784                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3785                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3786             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3787                                     "%qE between function pointer "
3788                                     "and %<void *%>"),
3789                                  G_("ISO C forbids assignment between "
3790                                     "function pointer and %<void *%>"),
3791                                  G_("ISO C forbids initialization between "
3792                                     "function pointer and %<void *%>"),
3793                                  G_("ISO C forbids return between function "
3794                                     "pointer and %<void *%>"));
3795           /* Const and volatile mean something different for function types,
3796              so the usual warnings are not appropriate.  */
3797           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3798                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3799             {
3800               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3801                 {
3802                   /* Types differing only by the presence of the 'volatile'
3803                      qualifier are acceptable if the 'volatile' has been added
3804                      in by the Objective-C EH machinery.  */
3805                   if (!objc_type_quals_match (ttl, ttr))
3806                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3807                                             "qualifiers from pointer target type"),
3808                                          G_("assignment discards qualifiers "
3809                                             "from pointer target type"),
3810                                          G_("initialization discards qualifiers "
3811                                             "from pointer target type"),
3812                                          G_("return discards qualifiers from "
3813                                             "pointer target type"));
3814                 }
3815               /* If this is not a case of ignoring a mismatch in signedness,
3816                  no warning.  */
3817               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3818                        || target_cmp)
3819                 ;
3820               /* If there is a mismatch, do warn.  */
3821               else if (warn_pointer_sign)
3822                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
3823                                         "%d of %qE differ in signedness"),
3824                                      G_("pointer targets in assignment "
3825                                         "differ in signedness"),
3826                                      G_("pointer targets in initialization "
3827                                         "differ in signedness"),
3828                                      G_("pointer targets in return differ "
3829                                         "in signedness"));
3830             }
3831           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3832                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3833             {
3834               /* Because const and volatile on functions are restrictions
3835                  that say the function will not do certain things,
3836                  it is okay to use a const or volatile function
3837                  where an ordinary one is wanted, but not vice-versa.  */
3838               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3839                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3840                                         "qualified function pointer "
3841                                         "from unqualified"),
3842                                      G_("assignment makes qualified function "
3843                                         "pointer from unqualified"),
3844                                      G_("initialization makes qualified "
3845                                         "function pointer from unqualified"),
3846                                      G_("return makes qualified function "
3847                                         "pointer from unqualified"));
3848             }
3849         }
3850       else
3851         /* Avoid warning about the volatile ObjC EH puts on decls.  */
3852         if (!objc_ok)
3853           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
3854                                   "incompatible pointer type"),
3855                                G_("assignment from incompatible pointer type"),
3856                                G_("initialization from incompatible "
3857                                   "pointer type"),
3858                                G_("return from incompatible pointer type"));
3859
3860       return convert (type, rhs);
3861     }
3862   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3863     {
3864       /* ??? This should not be an error when inlining calls to
3865          unprototyped functions.  */
3866       error ("invalid use of non-lvalue array");
3867       return error_mark_node;
3868     }
3869   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3870     {
3871       /* An explicit constant 0 can convert to a pointer,
3872          or one that results from arithmetic, even including
3873          a cast to integer type.  */
3874       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3875           &&
3876           !(TREE_CODE (rhs) == NOP_EXPR
3877             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3878             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3879             && integer_zerop (TREE_OPERAND (rhs, 0))))
3880         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3881                                 "pointer from integer without a cast"),
3882                              G_("assignment makes pointer from integer "
3883                                 "without a cast"),
3884                              G_("initialization makes pointer from "
3885                                 "integer without a cast"),
3886                              G_("return makes pointer from integer "
3887                                 "without a cast"));
3888
3889       return convert (type, rhs);
3890     }
3891   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3892     {
3893       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
3894                               "from pointer without a cast"),
3895                            G_("assignment makes integer from pointer "
3896                               "without a cast"),
3897                            G_("initialization makes integer from pointer "
3898                               "without a cast"),
3899                            G_("return makes integer from pointer "
3900                               "without a cast"));
3901       return convert (type, rhs);
3902     }
3903   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3904     return convert (type, rhs);
3905
3906   switch (errtype)
3907     {
3908     case ic_argpass:
3909     case ic_argpass_nonproto:
3910       /* ??? This should not be an error when inlining calls to
3911          unprototyped functions.  */
3912       error ("incompatible type for argument %d of %qE", parmnum, rname);
3913       break;
3914     case ic_assign:
3915       error ("incompatible types in assignment");
3916       break;
3917     case ic_init:
3918       error ("incompatible types in initialization");
3919       break;
3920     case ic_return:
3921       error ("incompatible types in return");
3922       break;
3923     default:
3924       gcc_unreachable ();
3925     }
3926
3927   return error_mark_node;
3928 }
3929
3930 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
3931    is used for error and waring reporting and indicates which argument
3932    is being processed.  */
3933
3934 tree
3935 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
3936 {
3937   tree ret, type;
3938
3939   /* If FN was prototyped, the value has been converted already
3940      in convert_arguments.  */
3941   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
3942     return value;
3943
3944   type = TREE_TYPE (parm);
3945   ret = convert_for_assignment (type, value,
3946                                 ic_argpass_nonproto, fn,
3947                                 fn, argnum);
3948   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
3949       && INTEGRAL_TYPE_P (type)
3950       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3951     ret = default_conversion (ret);
3952   return ret;
3953 }
3954 \f
3955 /* If VALUE is a compound expr all of whose expressions are constant, then
3956    return its value.  Otherwise, return error_mark_node.
3957
3958    This is for handling COMPOUND_EXPRs as initializer elements
3959    which is allowed with a warning when -pedantic is specified.  */
3960
3961 static tree
3962 valid_compound_expr_initializer (tree value, tree endtype)
3963 {
3964   if (TREE_CODE (value) == COMPOUND_EXPR)
3965     {
3966       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
3967           == error_mark_node)
3968         return error_mark_node;
3969       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
3970                                               endtype);
3971     }
3972   else if (!initializer_constant_valid_p (value, endtype))
3973     return error_mark_node;
3974   else
3975     return value;
3976 }
3977 \f
3978 /* Perform appropriate conversions on the initial value of a variable,
3979    store it in the declaration DECL,
3980    and print any error messages that are appropriate.
3981    If the init is invalid, store an ERROR_MARK.  */
3982
3983 void
3984 store_init_value (tree decl, tree init)
3985 {
3986   tree value, type;
3987
3988   /* If variable's type was invalidly declared, just ignore it.  */
3989
3990   type = TREE_TYPE (decl);
3991   if (TREE_CODE (type) == ERROR_MARK)
3992     return;
3993
3994   /* Digest the specified initializer into an expression.  */
3995
3996   value = digest_init (type, init, true, TREE_STATIC (decl));
3997
3998   /* Store the expression if valid; else report error.  */
3999
4000   if (warn_traditional && !in_system_header
4001       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4002     warning (0, "traditional C rejects automatic aggregate initialization");
4003
4004   DECL_INITIAL (decl) = value;
4005
4006   /* ANSI wants warnings about out-of-range constant initializers.  */
4007   STRIP_TYPE_NOPS (value);
4008   constant_expression_warning (value);
4009
4010   /* Check if we need to set array size from compound literal size.  */
4011   if (TREE_CODE (type) == ARRAY_TYPE
4012       && TYPE_DOMAIN (type) == 0
4013       && value != error_mark_node)
4014     {
4015       tree inside_init = init;
4016
4017       STRIP_TYPE_NOPS (inside_init);
4018       inside_init = fold (inside_init);
4019
4020       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4021         {
4022           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4023
4024           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4025             {
4026               /* For int foo[] = (int [3]){1}; we need to set array size
4027                  now since later on array initializer will be just the
4028                  brace enclosed list of the compound literal.  */
4029               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4030               layout_type (type);
4031               layout_decl (decl, 0);
4032             }
4033         }
4034     }
4035 }
4036 \f
4037 /* Methods for storing and printing names for error messages.  */
4038
4039 /* Implement a spelling stack that allows components of a name to be pushed
4040    and popped.  Each element on the stack is this structure.  */
4041
4042 struct spelling
4043 {
4044   int kind;
4045   union
4046     {
4047       int i;
4048       const char *s;
4049     } u;
4050 };
4051
4052 #define SPELLING_STRING 1
4053 #define SPELLING_MEMBER 2
4054 #define SPELLING_BOUNDS 3
4055
4056 static struct spelling *spelling;       /* Next stack element (unused).  */
4057 static struct spelling *spelling_base;  /* Spelling stack base.  */
4058 static int spelling_size;               /* Size of the spelling stack.  */
4059
4060 /* Macros to save and restore the spelling stack around push_... functions.
4061    Alternative to SAVE_SPELLING_STACK.  */
4062
4063 #define SPELLING_DEPTH() (spelling - spelling_base)
4064 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4065
4066 /* Push an element on the spelling stack with type KIND and assign VALUE
4067    to MEMBER.  */
4068
4069 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4070 {                                                                       \
4071   int depth = SPELLING_DEPTH ();                                        \
4072                                                                         \
4073   if (depth >= spelling_size)                                           \
4074     {                                                                   \
4075       spelling_size += 10;                                              \
4076       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4077                                   spelling_size);                       \
4078       RESTORE_SPELLING_DEPTH (depth);                                   \
4079     }                                                                   \
4080                                                                         \
4081   spelling->kind = (KIND);                                              \
4082   spelling->MEMBER = (VALUE);                                           \
4083   spelling++;                                                           \
4084 }
4085
4086 /* Push STRING on the stack.  Printed literally.  */
4087
4088 static void
4089 push_string (const char *string)
4090 {
4091   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4092 }
4093
4094 /* Push a member name on the stack.  Printed as '.' STRING.  */
4095
4096 static void
4097 push_member_name (tree decl)
4098 {
4099   const char *const string
4100     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4101   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4102 }
4103
4104 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4105
4106 static void
4107 push_array_bounds (int bounds)
4108 {
4109   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4110 }
4111
4112 /* Compute the maximum size in bytes of the printed spelling.  */
4113
4114 static int
4115 spelling_length (void)
4116 {
4117   int size = 0;
4118   struct spelling *p;
4119
4120   for (p = spelling_base; p < spelling; p++)
4121     {
4122       if (p->kind == SPELLING_BOUNDS)
4123         size += 25;
4124       else
4125         size += strlen (p->u.s) + 1;
4126     }
4127
4128   return size;
4129 }
4130
4131 /* Print the spelling to BUFFER and return it.  */
4132
4133 static char *
4134 print_spelling (char *buffer)
4135 {
4136   char *d = buffer;
4137   struct spelling *p;
4138
4139   for (p = spelling_base; p < spelling; p++)
4140     if (p->kind == SPELLING_BOUNDS)
4141       {
4142         sprintf (d, "[%d]", p->u.i);
4143         d += strlen (d);
4144       }
4145     else
4146       {
4147         const char *s;
4148         if (p->kind == SPELLING_MEMBER)
4149           *d++ = '.';
4150         for (s = p->u.s; (*d = *s++); d++)
4151           ;
4152       }
4153   *d++ = '\0';
4154   return buffer;
4155 }
4156
4157 /* Issue an error message for a bad initializer component.
4158    MSGID identifies the message.
4159    The component name is taken from the spelling stack.  */
4160
4161 void
4162 error_init (const char *msgid)
4163 {
4164   char *ofwhat;
4165
4166   error ("%s", _(msgid));
4167   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4168   if (*ofwhat)
4169     error ("(near initialization for %qs)", ofwhat);
4170 }
4171
4172 /* Issue a pedantic warning for a bad initializer component.
4173    MSGID identifies the message.
4174    The component name is taken from the spelling stack.  */
4175
4176 void
4177 pedwarn_init (const char *msgid)
4178 {
4179   char *ofwhat;
4180
4181   pedwarn ("%s", _(msgid));
4182   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4183   if (*ofwhat)
4184     pedwarn ("(near initialization for %qs)", ofwhat);
4185 }
4186
4187 /* Issue a warning for a bad initializer component.
4188    MSGID identifies the message.
4189    The component name is taken from the spelling stack.  */
4190
4191 static void
4192 warning_init (const char *msgid)
4193 {
4194   char *ofwhat;
4195
4196   warning (0, "%s", _(msgid));
4197   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4198   if (*ofwhat)
4199     warning (0, "(near initialization for %qs)", ofwhat);
4200 }
4201 \f
4202 /* If TYPE is an array type and EXPR is a parenthesized string
4203    constant, warn if pedantic that EXPR is being used to initialize an
4204    object of type TYPE.  */
4205
4206 void
4207 maybe_warn_string_init (tree type, struct c_expr expr)
4208 {
4209   if (pedantic
4210       && TREE_CODE (type) == ARRAY_TYPE
4211       && TREE_CODE (expr.value) == STRING_CST
4212       && expr.original_code != STRING_CST)
4213     pedwarn_init ("array initialized from parenthesized string constant");
4214 }
4215
4216 /* Digest the parser output INIT as an initializer for type TYPE.
4217    Return a C expression of type TYPE to represent the initial value.
4218
4219    If INIT is a string constant, STRICT_STRING is true if it is
4220    unparenthesized or we should not warn here for it being parenthesized.
4221    For other types of INIT, STRICT_STRING is not used.
4222
4223    REQUIRE_CONSTANT requests an error if non-constant initializers or
4224    elements are seen.  */
4225
4226 static tree
4227 digest_init (tree type, tree init, bool strict_string, int require_constant)
4228 {
4229   enum tree_code code = TREE_CODE (type);
4230   tree inside_init = init;
4231
4232   if (type == error_mark_node
4233       || init == error_mark_node
4234       || TREE_TYPE (init) == error_mark_node)
4235     return error_mark_node;
4236
4237   STRIP_TYPE_NOPS (inside_init);
4238
4239   inside_init = fold (inside_init);
4240
4241   /* Initialization of an array of chars from a string constant
4242      optionally enclosed in braces.  */
4243
4244   if (code == ARRAY_TYPE && inside_init
4245       && TREE_CODE (inside_init) == STRING_CST)
4246     {
4247       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4248       /* Note that an array could be both an array of character type
4249          and an array of wchar_t if wchar_t is signed char or unsigned
4250          char.  */
4251       bool char_array = (typ1 == char_type_node
4252                          || typ1 == signed_char_type_node
4253                          || typ1 == unsigned_char_type_node);
4254       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4255       if (char_array || wchar_array)
4256         {
4257           struct c_expr expr;
4258           bool char_string;
4259           expr.value = inside_init;
4260           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4261           maybe_warn_string_init (type, expr);
4262
4263           char_string
4264             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4265                == char_type_node);
4266
4267           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4268                          TYPE_MAIN_VARIANT (type)))
4269             return inside_init;
4270
4271           if (!wchar_array && !char_string)
4272             {
4273               error_init ("char-array initialized from wide string");
4274               return error_mark_node;
4275             }
4276           if (char_string && !char_array)
4277             {
4278               error_init ("wchar_t-array initialized from non-wide string");
4279               return error_mark_node;
4280             }
4281
4282           TREE_TYPE (inside_init) = type;
4283           if (TYPE_DOMAIN (type) != 0
4284               && TYPE_SIZE (type) != 0
4285               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4286               /* Subtract 1 (or sizeof (wchar_t))
4287                  because it's ok to ignore the terminating null char
4288                  that is counted in the length of the constant.  */
4289               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4290                                        TREE_STRING_LENGTH (inside_init)
4291                                        - ((TYPE_PRECISION (typ1)
4292                                            != TYPE_PRECISION (char_type_node))
4293                                           ? (TYPE_PRECISION (wchar_type_node)
4294                                              / BITS_PER_UNIT)
4295                                           : 1)))
4296             pedwarn_init ("initializer-string for array of chars is too long");
4297
4298           return inside_init;
4299         }
4300       else if (INTEGRAL_TYPE_P (typ1))
4301         {
4302           error_init ("array of inappropriate type initialized "
4303                       "from string constant");
4304           return error_mark_node;
4305         }
4306     }
4307
4308   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4309      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4310      below and handle as a constructor.  */
4311   if (code == VECTOR_TYPE
4312       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4313       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4314       && TREE_CONSTANT (inside_init))
4315     {
4316       if (TREE_CODE (inside_init) == VECTOR_CST
4317           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4318                         TYPE_MAIN_VARIANT (type)))
4319         return inside_init;
4320
4321       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4322         {
4323           tree link;
4324
4325           /* Iterate through elements and check if all constructor
4326              elements are *_CSTs.  */
4327           for (link = CONSTRUCTOR_ELTS (inside_init);
4328                link;
4329                link = TREE_CHAIN (link))
4330             if (! CONSTANT_CLASS_P (TREE_VALUE (link)))
4331               break;
4332
4333           if (link == NULL)
4334             return build_vector (type, CONSTRUCTOR_ELTS (inside_init));
4335         }
4336     }
4337
4338   /* Any type can be initialized
4339      from an expression of the same type, optionally with braces.  */
4340
4341   if (inside_init && TREE_TYPE (inside_init) != 0
4342       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4343                      TYPE_MAIN_VARIANT (type))
4344           || (code == ARRAY_TYPE
4345               && comptypes (TREE_TYPE (inside_init), type))
4346           || (code == VECTOR_TYPE
4347               && comptypes (TREE_TYPE (inside_init), type))
4348           || (code == POINTER_TYPE
4349               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4350               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4351                             TREE_TYPE (type)))))
4352     {
4353       if (code == POINTER_TYPE)
4354         {
4355           if (TREE_CODE (inside_init) == STRING_CST
4356               || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4357             inside_init = default_function_array_conversion (inside_init);
4358
4359           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4360             {
4361               error_init ("invalid use of non-lvalue array");
4362               return error_mark_node;
4363             }
4364          }
4365
4366       if (code == VECTOR_TYPE)
4367         /* Although the types are compatible, we may require a
4368            conversion.  */
4369         inside_init = convert (type, inside_init);
4370
4371       if (require_constant && !flag_isoc99
4372           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4373         {
4374           /* As an extension, allow initializing objects with static storage
4375              duration with compound literals (which are then treated just as
4376              the brace enclosed list they contain).  */
4377           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4378           inside_init = DECL_INITIAL (decl);
4379         }
4380
4381       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4382           && TREE_CODE (inside_init) != CONSTRUCTOR)
4383         {
4384           error_init ("array initialized from non-constant array expression");
4385           return error_mark_node;
4386         }
4387
4388       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4389         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4390
4391       /* Compound expressions can only occur here if -pedantic or
4392          -pedantic-errors is specified.  In the later case, we always want
4393          an error.  In the former case, we simply want a warning.  */
4394       if (require_constant && pedantic
4395           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4396         {
4397           inside_init
4398             = valid_compound_expr_initializer (inside_init,
4399                                                TREE_TYPE (inside_init));
4400           if (inside_init == error_mark_node)
4401             error_init ("initializer element is not constant");
4402           else
4403             pedwarn_init ("initializer element is not constant");
4404           if (flag_pedantic_errors)
4405             inside_init = error_mark_node;
4406         }
4407       else if (require_constant
4408                && !initializer_constant_valid_p (inside_init,
4409                                                  TREE_TYPE (inside_init)))
4410         {
4411           error_init ("initializer element is not constant");
4412           inside_init = error_mark_node;
4413         }
4414
4415       return inside_init;
4416     }
4417
4418   /* Handle scalar types, including conversions.  */
4419
4420   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4421       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4422       || code == VECTOR_TYPE)
4423     {
4424       if (TREE_CODE (init) == STRING_CST
4425           || TREE_CODE (init) == COMPOUND_LITERAL_EXPR)
4426         init = default_function_array_conversion (init);
4427       inside_init
4428         = convert_for_assignment (type, init, ic_init,
4429                                   NULL_TREE, NULL_TREE, 0);
4430
4431       /* Check to see if we have already given an error message.  */
4432       if (inside_init == error_mark_node)
4433         ;
4434       else if (require_constant && !TREE_CONSTANT (inside_init))
4435         {
4436           error_init ("initializer element is not constant");
4437           inside_init = error_mark_node;
4438         }
4439       else if (require_constant
4440                && !initializer_constant_valid_p (inside_init,
4441                                                  TREE_TYPE (inside_init)))
4442         {
4443           error_init ("initializer element is not computable at load time");
4444           inside_init = error_mark_node;
4445         }
4446
4447       return inside_init;
4448     }
4449
4450   /* Come here only for records and arrays.  */
4451
4452   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4453     {
4454       error_init ("variable-sized object may not be initialized");
4455       return error_mark_node;
4456     }
4457
4458   error_init ("invalid initializer");
4459   return error_mark_node;
4460 }
4461 \f
4462 /* Handle initializers that use braces.  */
4463
4464 /* Type of object we are accumulating a constructor for.
4465    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4466 static tree constructor_type;
4467
4468 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4469    left to fill.  */
4470 static tree constructor_fields;
4471
4472 /* For an ARRAY_TYPE, this is the specified index
4473    at which to store the next element we get.  */
4474 static tree constructor_index;
4475
4476 /* For an ARRAY_TYPE, this is the maximum index.  */
4477 static tree constructor_max_index;
4478
4479 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4480 static tree constructor_unfilled_fields;
4481
4482 /* For an ARRAY_TYPE, this is the index of the first element
4483    not yet written out.  */
4484 static tree constructor_unfilled_index;
4485
4486 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4487    This is so we can generate gaps between fields, when appropriate.  */
4488 static tree constructor_bit_index;
4489
4490 /* If we are saving up the elements rather than allocating them,
4491    this is the list of elements so far (in reverse order,
4492    most recent first).  */
4493 static tree constructor_elements;
4494
4495 /* 1 if constructor should be incrementally stored into a constructor chain,
4496    0 if all the elements should be kept in AVL tree.  */
4497 static int constructor_incremental;
4498
4499 /* 1 if so far this constructor's elements are all compile-time constants.  */
4500 static int constructor_constant;
4501
4502 /* 1 if so far this constructor's elements are all valid address constants.  */
4503 static int constructor_simple;
4504
4505 /* 1 if this constructor is erroneous so far.  */
4506 static int constructor_erroneous;
4507
4508 /* Structure for managing pending initializer elements, organized as an
4509    AVL tree.  */
4510
4511 struct init_node
4512 {
4513   struct init_node *left, *right;
4514   struct init_node *parent;
4515   int balance;
4516   tree purpose;
4517   tree value;
4518 };
4519
4520 /* Tree of pending elements at this constructor level.
4521    These are elements encountered out of order
4522    which belong at places we haven't reached yet in actually
4523    writing the output.
4524    Will never hold tree nodes across GC runs.  */
4525 static struct init_node *constructor_pending_elts;
4526
4527 /* The SPELLING_DEPTH of this constructor.  */
4528 static int constructor_depth;
4529
4530 /* DECL node for which an initializer is being read.
4531    0 means we are reading a constructor expression
4532    such as (struct foo) {...}.  */
4533 static tree constructor_decl;
4534
4535 /* Nonzero if this is an initializer for a top-level decl.  */
4536 static int constructor_top_level;
4537
4538 /* Nonzero if there were any member designators in this initializer.  */
4539 static int constructor_designated;
4540
4541 /* Nesting depth of designator list.  */
4542 static int designator_depth;
4543
4544 /* Nonzero if there were diagnosed errors in this designator list.  */
4545 static int designator_errorneous;
4546
4547 \f
4548 /* This stack has a level for each implicit or explicit level of
4549    structuring in the initializer, including the outermost one.  It
4550    saves the values of most of the variables above.  */
4551
4552 struct constructor_range_stack;
4553
4554 struct constructor_stack
4555 {
4556   struct constructor_stack *next;
4557   tree type;
4558   tree fields;
4559   tree index;
4560   tree max_index;
4561   tree unfilled_index;
4562   tree unfilled_fields;
4563   tree bit_index;
4564   tree elements;
4565   struct init_node *pending_elts;
4566   int offset;
4567   int depth;
4568   /* If value nonzero, this value should replace the entire
4569      constructor at this level.  */
4570   struct c_expr replacement_value;
4571   struct constructor_range_stack *range_stack;
4572   char constant;
4573   char simple;
4574   char implicit;
4575   char erroneous;
4576   char outer;
4577   char incremental;
4578   char designated;
4579 };
4580
4581 static struct constructor_stack *constructor_stack;
4582
4583 /* This stack represents designators from some range designator up to
4584    the last designator in the list.  */
4585
4586 struct constructor_range_stack
4587 {
4588   struct constructor_range_stack *next, *prev;
4589   struct constructor_stack *stack;
4590   tree range_start;
4591   tree index;
4592   tree range_end;
4593   tree fields;
4594 };
4595
4596 static struct constructor_range_stack *constructor_range_stack;
4597
4598 /* This stack records separate initializers that are nested.
4599    Nested initializers can't happen in ANSI C, but GNU C allows them
4600    in cases like { ... (struct foo) { ... } ... }.  */
4601
4602 struct initializer_stack
4603 {
4604   struct initializer_stack *next;
4605   tree decl;
4606   struct constructor_stack *constructor_stack;
4607   struct constructor_range_stack *constructor_range_stack;
4608   tree elements;
4609   struct spelling *spelling;
4610   struct spelling *spelling_base;
4611   int spelling_size;
4612   char top_level;
4613   char require_constant_value;
4614   char require_constant_elements;
4615 };
4616
4617 static struct initializer_stack *initializer_stack;
4618 \f
4619 /* Prepare to parse and output the initializer for variable DECL.  */
4620
4621 void
4622 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4623 {
4624   const char *locus;
4625   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4626
4627   p->decl = constructor_decl;
4628   p->require_constant_value = require_constant_value;
4629   p->require_constant_elements = require_constant_elements;
4630   p->constructor_stack = constructor_stack;
4631   p->constructor_range_stack = constructor_range_stack;
4632   p->elements = constructor_elements;
4633   p->spelling = spelling;
4634   p->spelling_base = spelling_base;
4635   p->spelling_size = spelling_size;
4636   p->top_level = constructor_top_level;
4637   p->next = initializer_stack;
4638   initializer_stack = p;
4639
4640   constructor_decl = decl;
4641   constructor_designated = 0;
4642   constructor_top_level = top_level;
4643
4644   if (decl != 0 && decl != error_mark_node)
4645     {
4646       require_constant_value = TREE_STATIC (decl);
4647       require_constant_elements
4648         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4649            /* For a scalar, you can always use any value to initialize,
4650               even within braces.  */
4651            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4652                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4653                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4654                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4655       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4656     }
4657   else
4658     {
4659       require_constant_value = 0;
4660       require_constant_elements = 0;
4661       locus = "(anonymous)";
4662     }
4663
4664   constructor_stack = 0;
4665   constructor_range_stack = 0;
4666
4667   missing_braces_mentioned = 0;
4668
4669   spelling_base = 0;
4670   spelling_size = 0;
4671   RESTORE_SPELLING_DEPTH (0);
4672
4673   if (locus)
4674     push_string (locus);
4675 }
4676
4677 void
4678 finish_init (void)
4679 {
4680   struct initializer_stack *p = initializer_stack;
4681
4682   /* Free the whole constructor stack of this initializer.  */
4683   while (constructor_stack)
4684     {
4685       struct constructor_stack *q = constructor_stack;
4686       constructor_stack = q->next;
4687       free (q);
4688     }
4689
4690   gcc_assert (!constructor_range_stack);
4691
4692   /* Pop back to the data of the outer initializer (if any).  */
4693   free (spelling_base);
4694
4695   constructor_decl = p->decl;
4696   require_constant_value = p->require_constant_value;
4697   require_constant_elements = p->require_constant_elements;
4698   constructor_stack = p->constructor_stack;
4699   constructor_range_stack = p->constructor_range_stack;
4700   constructor_elements = p->elements;
4701   spelling = p->spelling;
4702   spelling_base = p->spelling_base;
4703   spelling_size = p->spelling_size;
4704   constructor_top_level = p->top_level;
4705   initializer_stack = p->next;
4706   free (p);
4707 }
4708 \f
4709 /* Call here when we see the initializer is surrounded by braces.
4710    This is instead of a call to push_init_level;
4711    it is matched by a call to pop_init_level.
4712
4713    TYPE is the type to initialize, for a constructor expression.
4714    For an initializer for a decl, TYPE is zero.  */
4715
4716 void
4717 really_start_incremental_init (tree type)
4718 {
4719   struct constructor_stack *p = XNEW (struct constructor_stack);
4720
4721   if (type == 0)
4722     type = TREE_TYPE (constructor_decl);
4723
4724   if (targetm.vector_opaque_p (type))
4725     error ("opaque vector types cannot be initialized");
4726
4727   p->type = constructor_type;
4728   p->fields = constructor_fields;
4729   p->index = constructor_index;
4730   p->max_index = constructor_max_index;
4731   p->unfilled_index = constructor_unfilled_index;
4732   p->unfilled_fields = constructor_unfilled_fields;
4733   p->bit_index = constructor_bit_index;
4734   p->elements = constructor_elements;
4735   p->constant = constructor_constant;
4736   p->simple = constructor_simple;
4737   p->erroneous = constructor_erroneous;
4738   p->pending_elts = constructor_pending_elts;
4739   p->depth = constructor_depth;
4740   p->replacement_value.value = 0;
4741   p->replacement_value.original_code = ERROR_MARK;
4742   p->implicit = 0;
4743   p->range_stack = 0;
4744   p->outer = 0;
4745   p->incremental = constructor_incremental;
4746   p->designated = constructor_designated;
4747   p->next = 0;
4748   constructor_stack = p;
4749
4750   constructor_constant = 1;
4751   constructor_simple = 1;
4752   constructor_depth = SPELLING_DEPTH ();
4753   constructor_elements = 0;
4754   constructor_pending_elts = 0;
4755   constructor_type = type;
4756   constructor_incremental = 1;
4757   constructor_designated = 0;
4758   designator_depth = 0;
4759   designator_errorneous = 0;
4760
4761   if (TREE_CODE (constructor_type) == RECORD_TYPE
4762       || TREE_CODE (constructor_type) == UNION_TYPE)
4763     {
4764       constructor_fields = TYPE_FIELDS (constructor_type);
4765       /* Skip any nameless bit fields at the beginning.  */
4766       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4767              && DECL_NAME (constructor_fields) == 0)
4768         constructor_fields = TREE_CHAIN (constructor_fields);
4769
4770       constructor_unfilled_fields = constructor_fields;
4771       constructor_bit_index = bitsize_zero_node;
4772     }
4773   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4774     {
4775       if (TYPE_DOMAIN (constructor_type))
4776         {
4777           constructor_max_index
4778             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4779
4780           /* Detect non-empty initializations of zero-length arrays.  */
4781           if (constructor_max_index == NULL_TREE
4782               && TYPE_SIZE (constructor_type))
4783             constructor_max_index = build_int_cst (NULL_TREE, -1);
4784
4785           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4786              to initialize VLAs will cause a proper error; avoid tree
4787              checking errors as well by setting a safe value.  */
4788           if (constructor_max_index
4789               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4790             constructor_max_index = build_int_cst (NULL_TREE, -1);
4791
4792           constructor_index
4793             = convert (bitsizetype,
4794                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4795         }
4796       else
4797         {
4798           constructor_index = bitsize_zero_node;
4799           constructor_max_index = NULL_TREE;
4800         }
4801
4802       constructor_unfilled_index = constructor_index;
4803     }
4804   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4805     {
4806       /* Vectors are like simple fixed-size arrays.  */
4807       constructor_max_index =
4808         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4809       constructor_index = convert (bitsizetype, bitsize_zero_node);
4810       constructor_unfilled_index = constructor_index;
4811     }
4812   else
4813     {
4814       /* Handle the case of int x = {5}; */
4815       constructor_fields = constructor_type;
4816       constructor_unfilled_fields = constructor_type;
4817     }
4818 }
4819 \f
4820 /* Push down into a subobject, for initialization.
4821    If this is for an explicit set of braces, IMPLICIT is 0.
4822    If it is because the next element belongs at a lower level,
4823    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4824
4825 void
4826 push_init_level (int implicit)
4827 {
4828   struct constructor_stack *p;
4829   tree value = NULL_TREE;
4830
4831   /* If we've exhausted any levels that didn't have braces,
4832      pop them now.  If implicit == 1, this will have been done in
4833      process_init_element; do not repeat it here because in the case
4834      of excess initializers for an empty aggregate this leads to an
4835      infinite cycle of popping a level and immediately recreating
4836      it.  */
4837   if (implicit != 1)
4838     {
4839       while (constructor_stack->implicit)
4840         {
4841           if ((TREE_CODE (constructor_type) == RECORD_TYPE
4842                || TREE_CODE (constructor_type) == UNION_TYPE)
4843               && constructor_fields == 0)
4844             process_init_element (pop_init_level (1));
4845           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4846                    && constructor_max_index
4847                    && tree_int_cst_lt (constructor_max_index,
4848                                        constructor_index))
4849             process_init_element (pop_init_level (1));
4850           else
4851             break;
4852         }
4853     }
4854
4855   /* Unless this is an explicit brace, we need to preserve previous
4856      content if any.  */
4857   if (implicit)
4858     {
4859       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4860            || TREE_CODE (constructor_type) == UNION_TYPE)
4861           && constructor_fields)
4862         value = find_init_member (constructor_fields);
4863       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4864         value = find_init_member (constructor_index);
4865     }
4866
4867   p = XNEW (struct constructor_stack);
4868   p->type = constructor_type;
4869   p->fields = constructor_fields;
4870   p->index = constructor_index;
4871   p->max_index = constructor_max_index;
4872   p->unfilled_index = constructor_unfilled_index;
4873   p->unfilled_fields = constructor_unfilled_fields;
4874   p->bit_index = constructor_bit_index;
4875   p->elements = constructor_elements;
4876   p->constant = constructor_constant;
4877   p->simple = constructor_simple;
4878   p->erroneous = constructor_erroneous;
4879   p->pending_elts = constructor_pending_elts;
4880   p->depth = constructor_depth;
4881   p->replacement_value.value = 0;
4882   p->replacement_value.original_code = ERROR_MARK;
4883   p->implicit = implicit;
4884   p->outer = 0;
4885   p->incremental = constructor_incremental;
4886   p->designated = constructor_designated;
4887   p->next = constructor_stack;
4888   p->range_stack = 0;
4889   constructor_stack = p;
4890
4891   constructor_constant = 1;
4892   constructor_simple = 1;
4893   constructor_depth = SPELLING_DEPTH ();
4894   constructor_elements = 0;
4895   constructor_incremental = 1;
4896   constructor_designated = 0;
4897   constructor_pending_elts = 0;
4898   if (!implicit)
4899     {
4900       p->range_stack = constructor_range_stack;
4901       constructor_range_stack = 0;
4902       designator_depth = 0;
4903       designator_errorneous = 0;
4904     }
4905
4906   /* Don't die if an entire brace-pair level is superfluous
4907      in the containing level.  */
4908   if (constructor_type == 0)
4909     ;
4910   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4911            || TREE_CODE (constructor_type) == UNION_TYPE)
4912     {
4913       /* Don't die if there are extra init elts at the end.  */
4914       if (constructor_fields == 0)
4915         constructor_type = 0;
4916       else
4917         {
4918           constructor_type = TREE_TYPE (constructor_fields);
4919           push_member_name (constructor_fields);
4920           constructor_depth++;
4921         }
4922     }
4923   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4924     {
4925       constructor_type = TREE_TYPE (constructor_type);
4926       push_array_bounds (tree_low_cst (constructor_index, 0));
4927       constructor_depth++;
4928     }
4929
4930   if (constructor_type == 0)
4931     {
4932       error_init ("extra brace group at end of initializer");
4933       constructor_fields = 0;
4934       constructor_unfilled_fields = 0;
4935       return;
4936     }
4937
4938   if (value && TREE_CODE (value) == CONSTRUCTOR)
4939     {
4940       constructor_constant = TREE_CONSTANT (value);
4941       constructor_simple = TREE_STATIC (value);
4942       constructor_elements = CONSTRUCTOR_ELTS (value);
4943       if (constructor_elements
4944           && (TREE_CODE (constructor_type) == RECORD_TYPE
4945               || TREE_CODE (constructor_type) == ARRAY_TYPE))
4946         set_nonincremental_init ();
4947     }
4948
4949   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
4950     {
4951       missing_braces_mentioned = 1;
4952       warning_init ("missing braces around initializer");
4953     }
4954
4955   if (TREE_CODE (constructor_type) == RECORD_TYPE
4956            || TREE_CODE (constructor_type) == UNION_TYPE)
4957     {
4958       constructor_fields = TYPE_FIELDS (constructor_type);
4959       /* Skip any nameless bit fields at the beginning.  */
4960       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4961              && DECL_NAME (constructor_fields) == 0)
4962         constructor_fields = TREE_CHAIN (constructor_fields);
4963
4964       constructor_unfilled_fields = constructor_fields;
4965       constructor_bit_index = bitsize_zero_node;
4966     }
4967   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4968     {
4969       /* Vectors are like simple fixed-size arrays.  */
4970       constructor_max_index =
4971         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4972       constructor_index = convert (bitsizetype, integer_zero_node);
4973       constructor_unfilled_index = constructor_index;
4974     }
4975   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4976     {
4977       if (TYPE_DOMAIN (constructor_type))
4978         {
4979           constructor_max_index
4980             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4981
4982           /* Detect non-empty initializations of zero-length arrays.  */
4983           if (constructor_max_index == NULL_TREE
4984               && TYPE_SIZE (constructor_type))
4985             constructor_max_index = build_int_cst (NULL_TREE, -1);
4986
4987           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4988              to initialize VLAs will cause a proper error; avoid tree
4989              checking errors as well by setting a safe value.  */
4990           if (constructor_max_index
4991               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4992             constructor_max_index = build_int_cst (NULL_TREE, -1);
4993
4994           constructor_index
4995             = convert (bitsizetype,
4996                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4997         }
4998       else
4999         constructor_index = bitsize_zero_node;
5000
5001       constructor_unfilled_index = constructor_index;
5002       if (value && TREE_CODE (value) == STRING_CST)
5003         {
5004           /* We need to split the char/wchar array into individual
5005              characters, so that we don't have to special case it
5006              everywhere.  */
5007           set_nonincremental_init_from_string (value);
5008         }
5009     }
5010   else
5011     {
5012       if (constructor_type != error_mark_node)
5013         warning_init ("braces around scalar initializer");
5014       constructor_fields = constructor_type;
5015       constructor_unfilled_fields = constructor_type;
5016     }
5017 }
5018
5019 /* At the end of an implicit or explicit brace level,
5020    finish up that level of constructor.  If a single expression
5021    with redundant braces initialized that level, return the
5022    c_expr structure for that expression.  Otherwise, the original_code
5023    element is set to ERROR_MARK.
5024    If we were outputting the elements as they are read, return 0 as the value
5025    from inner levels (process_init_element ignores that),
5026    but return error_mark_node as the value from the outermost level
5027    (that's what we want to put in DECL_INITIAL).
5028    Otherwise, return a CONSTRUCTOR expression as the value.  */
5029
5030 struct c_expr
5031 pop_init_level (int implicit)
5032 {
5033   struct constructor_stack *p;
5034   struct c_expr ret;
5035   ret.value = 0;
5036   ret.original_code = ERROR_MARK;
5037
5038   if (implicit == 0)
5039     {
5040       /* When we come to an explicit close brace,
5041          pop any inner levels that didn't have explicit braces.  */
5042       while (constructor_stack->implicit)
5043         process_init_element (pop_init_level (1));
5044
5045       gcc_assert (!constructor_range_stack);
5046     }
5047
5048   /* Now output all pending elements.  */
5049   constructor_incremental = 1;
5050   output_pending_init_elements (1);
5051
5052   p = constructor_stack;
5053
5054   /* Error for initializing a flexible array member, or a zero-length
5055      array member in an inappropriate context.  */
5056   if (constructor_type && constructor_fields
5057       && TREE_CODE (constructor_type) == ARRAY_TYPE
5058       && TYPE_DOMAIN (constructor_type)
5059       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5060     {
5061       /* Silently discard empty initializations.  The parser will
5062          already have pedwarned for empty brackets.  */
5063       if (integer_zerop (constructor_unfilled_index))
5064         constructor_type = NULL_TREE;
5065       else
5066         {
5067           gcc_assert (!TYPE_SIZE (constructor_type));
5068
5069           if (constructor_depth > 2)
5070             error_init ("initialization of flexible array member in a nested context");
5071           else if (pedantic)
5072             pedwarn_init ("initialization of a flexible array member");
5073
5074           /* We have already issued an error message for the existence
5075              of a flexible array member not at the end of the structure.
5076              Discard the initializer so that we do not die later.  */
5077           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5078             constructor_type = NULL_TREE;
5079         }
5080     }
5081
5082   /* Warn when some struct elements are implicitly initialized to zero.  */
5083   if (warn_missing_field_initializers
5084       && constructor_type
5085       && TREE_CODE (constructor_type) == RECORD_TYPE
5086       && constructor_unfilled_fields)
5087     {
5088         /* Do not warn for flexible array members or zero-length arrays.  */
5089         while (constructor_unfilled_fields
5090                && (!DECL_SIZE (constructor_unfilled_fields)
5091                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5092           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5093
5094         /* Do not warn if this level of the initializer uses member
5095            designators; it is likely to be deliberate.  */
5096         if (constructor_unfilled_fields && !constructor_designated)
5097           {
5098             push_member_name (constructor_unfilled_fields);
5099             warning_init ("missing initializer");
5100             RESTORE_SPELLING_DEPTH (constructor_depth);
5101           }
5102     }
5103
5104   /* Pad out the end of the structure.  */
5105   if (p->replacement_value.value)
5106     /* If this closes a superfluous brace pair,
5107        just pass out the element between them.  */
5108     ret = p->replacement_value;
5109   else if (constructor_type == 0)
5110     ;
5111   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5112            && TREE_CODE (constructor_type) != UNION_TYPE
5113            && TREE_CODE (constructor_type) != ARRAY_TYPE
5114            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5115     {
5116       /* A nonincremental scalar initializer--just return
5117          the element, after verifying there is just one.  */
5118       if (constructor_elements == 0)
5119         {
5120           if (!constructor_erroneous)
5121             error_init ("empty scalar initializer");
5122           ret.value = error_mark_node;
5123         }
5124       else if (TREE_CHAIN (constructor_elements) != 0)
5125         {
5126           error_init ("extra elements in scalar initializer");
5127           ret.value = TREE_VALUE (constructor_elements);
5128         }
5129       else
5130         ret.value = TREE_VALUE (constructor_elements);
5131     }
5132   else
5133     {
5134       if (constructor_erroneous)
5135         ret.value = error_mark_node;
5136       else
5137         {
5138           ret.value = build_constructor (constructor_type,
5139                                          nreverse (constructor_elements));
5140           if (constructor_constant)
5141             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5142           if (constructor_constant && constructor_simple)
5143             TREE_STATIC (ret.value) = 1;
5144         }
5145     }
5146
5147   constructor_type = p->type;
5148   constructor_fields = p->fields;
5149   constructor_index = p->index;
5150   constructor_max_index = p->max_index;
5151   constructor_unfilled_index = p->unfilled_index;
5152   constructor_unfilled_fields = p->unfilled_fields;
5153   constructor_bit_index = p->bit_index;
5154   constructor_elements = p->elements;
5155   constructor_constant = p->constant;
5156   constructor_simple = p->simple;
5157   constructor_erroneous = p->erroneous;
5158   constructor_incremental = p->incremental;
5159   constructor_designated = p->designated;
5160   constructor_pending_elts = p->pending_elts;
5161   constructor_depth = p->depth;
5162   if (!p->implicit)
5163     constructor_range_stack = p->range_stack;
5164   RESTORE_SPELLING_DEPTH (constructor_depth);
5165
5166   constructor_stack = p->next;
5167   free (p);
5168
5169   if (ret.value == 0)
5170     {
5171       if (constructor_stack == 0)
5172         {
5173           ret.value = error_mark_node;
5174           return ret;
5175         }
5176       return ret;
5177     }
5178   return ret;
5179 }
5180
5181 /* Common handling for both array range and field name designators.
5182    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5183
5184 static int
5185 set_designator (int array)
5186 {
5187   tree subtype;
5188   enum tree_code subcode;
5189
5190   /* Don't die if an entire brace-pair level is superfluous
5191      in the containing level.  */
5192   if (constructor_type == 0)
5193     return 1;
5194
5195   /* If there were errors in this designator list already, bail out
5196      silently.  */
5197   if (designator_errorneous)
5198     return 1;
5199
5200   if (!designator_depth)
5201     {
5202       gcc_assert (!constructor_range_stack);
5203
5204       /* Designator list starts at the level of closest explicit
5205          braces.  */
5206       while (constructor_stack->implicit)
5207         process_init_element (pop_init_level (1));
5208       constructor_designated = 1;
5209       return 0;
5210     }
5211
5212   switch (TREE_CODE (constructor_type))
5213     {
5214     case  RECORD_TYPE:
5215     case  UNION_TYPE:
5216       subtype = TREE_TYPE (constructor_fields);
5217       if (subtype != error_mark_node)
5218         subtype = TYPE_MAIN_VARIANT (subtype);
5219       break;
5220     case ARRAY_TYPE:
5221       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5222       break;
5223     default:
5224       gcc_unreachable ();
5225     }
5226
5227   subcode = TREE_CODE (subtype);
5228   if (array && subcode != ARRAY_TYPE)
5229     {
5230       error_init ("array index in non-array initializer");
5231       return 1;
5232     }
5233   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5234     {
5235       error_init ("field name not in record or union initializer");
5236       return 1;
5237     }
5238
5239   constructor_designated = 1;
5240   push_init_level (2);
5241   return 0;
5242 }
5243
5244 /* If there are range designators in designator list, push a new designator
5245    to constructor_range_stack.  RANGE_END is end of such stack range or
5246    NULL_TREE if there is no range designator at this level.  */
5247
5248 static void
5249 push_range_stack (tree range_end)
5250 {
5251   struct constructor_range_stack *p;
5252
5253   p = GGC_NEW (struct constructor_range_stack);
5254   p->prev = constructor_range_stack;
5255   p->next = 0;
5256   p->fields = constructor_fields;
5257   p->range_start = constructor_index;
5258   p->index = constructor_index;
5259   p->stack = constructor_stack;
5260   p->range_end = range_end;
5261   if (constructor_range_stack)
5262     constructor_range_stack->next = p;
5263   constructor_range_stack = p;
5264 }
5265
5266 /* Within an array initializer, specify the next index to be initialized.
5267    FIRST is that index.  If LAST is nonzero, then initialize a range
5268    of indices, running from FIRST through LAST.  */
5269
5270 void
5271 set_init_index (tree first, tree last)
5272 {
5273   if (set_designator (1))
5274     return;
5275
5276   designator_errorneous = 1;
5277
5278   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5279       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5280     {
5281       error_init ("array index in initializer not of integer type");
5282       return;
5283     }
5284
5285   if (TREE_CODE (first) != INTEGER_CST)
5286     error_init ("nonconstant array index in initializer");
5287   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5288     error_init ("nonconstant array index in initializer");
5289   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5290     error_init ("array index in non-array initializer");
5291   else if (tree_int_cst_sgn (first) == -1)
5292     error_init ("array index in initializer exceeds array bounds");
5293   else if (constructor_max_index
5294            && tree_int_cst_lt (constructor_max_index, first))
5295     error_init ("array index in initializer exceeds array bounds");
5296   else
5297     {
5298       constructor_index = convert (bitsizetype, first);
5299
5300       if (last)
5301         {
5302           if (tree_int_cst_equal (first, last))
5303             last = 0;
5304           else if (tree_int_cst_lt (last, first))
5305             {
5306               error_init ("empty index range in initializer");
5307               last = 0;
5308             }
5309           else
5310             {
5311               last = convert (bitsizetype, last);
5312               if (constructor_max_index != 0
5313                   && tree_int_cst_lt (constructor_max_index, last))
5314                 {
5315                   error_init ("array index range in initializer exceeds array bounds");
5316                   last = 0;
5317                 }
5318             }
5319         }
5320
5321       designator_depth++;
5322       designator_errorneous = 0;
5323       if (constructor_range_stack || last)
5324         push_range_stack (last);
5325     }
5326 }
5327
5328 /* Within a struct initializer, specify the next field to be initialized.  */
5329
5330 void
5331 set_init_label (tree fieldname)
5332 {
5333   tree tail;
5334
5335   if (set_designator (0))
5336     return;
5337
5338   designator_errorneous = 1;
5339
5340   if (TREE_CODE (constructor_type) != RECORD_TYPE
5341       && TREE_CODE (constructor_type) != UNION_TYPE)
5342     {
5343       error_init ("field name not in record or union initializer");
5344       return;
5345     }
5346
5347   for (tail = TYPE_FIELDS (constructor_type); tail;
5348        tail = TREE_CHAIN (tail))
5349     {
5350       if (DECL_NAME (tail) == fieldname)
5351         break;
5352     }
5353
5354   if (tail == 0)
5355     error ("unknown field %qE specified in initializer", fieldname);
5356   else
5357     {
5358       constructor_fields = tail;
5359       designator_depth++;
5360       designator_errorneous = 0;
5361       if (constructor_range_stack)
5362         push_range_stack (NULL_TREE);
5363     }
5364 }
5365 \f
5366 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5367    identifies the initializer, either array index or field in a structure.
5368    VALUE is the value of that index or field.  */
5369
5370 static void
5371 add_pending_init (tree purpose, tree value)
5372 {
5373   struct init_node *p, **q, *r;
5374
5375   q = &constructor_pending_elts;
5376   p = 0;
5377
5378   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5379     {
5380       while (*q != 0)
5381         {
5382           p = *q;
5383           if (tree_int_cst_lt (purpose, p->purpose))
5384             q = &p->left;
5385           else if (tree_int_cst_lt (p->purpose, purpose))
5386             q = &p->right;
5387           else
5388             {
5389               if (TREE_SIDE_EFFECTS (p->value))
5390                 warning_init ("initialized field with side-effects overwritten");
5391               p->value = value;
5392               return;
5393             }
5394         }
5395     }
5396   else
5397     {
5398       tree bitpos;
5399
5400       bitpos = bit_position (purpose);
5401       while (*q != NULL)
5402         {
5403           p = *q;
5404           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5405             q = &p->left;
5406           else if (p->purpose != purpose)
5407             q = &p->right;
5408           else
5409             {
5410               if (TREE_SIDE_EFFECTS (p->value))
5411                 warning_init ("initialized field with side-effects overwritten");
5412               p->value = value;
5413               return;
5414             }
5415         }
5416     }
5417
5418   r = GGC_NEW (struct init_node);
5419   r->purpose = purpose;
5420   r->value = value;
5421
5422   *q = r;
5423   r->parent = p;
5424   r->left = 0;
5425   r->right = 0;
5426   r->balance = 0;
5427
5428   while (p)
5429     {
5430       struct init_node *s;
5431
5432       if (r == p->left)
5433         {
5434           if (p->balance == 0)
5435             p->balance = -1;
5436           else if (p->balance < 0)
5437             {
5438               if (r->balance < 0)
5439                 {
5440                   /* L rotation.  */
5441                   p->left = r->right;
5442                   if (p->left)
5443                     p->left->parent = p;
5444                   r->right = p;
5445
5446                   p->balance = 0;
5447                   r->balance = 0;
5448
5449                   s = p->parent;
5450                   p->parent = r;
5451                   r->parent = s;
5452                   if (s)
5453                     {
5454                       if (s->left == p)
5455                         s->left = r;
5456                       else
5457                         s->right = r;
5458                     }
5459                   else
5460                     constructor_pending_elts = r;
5461                 }
5462               else
5463                 {
5464                   /* LR rotation.  */
5465                   struct init_node *t = r->right;
5466
5467                   r->right = t->left;
5468                   if (r->right)
5469                     r->right->parent = r;
5470                   t->left = r;
5471
5472                   p->left = t->right;
5473                   if (p->left)
5474                     p->left->parent = p;
5475                   t->right = p;
5476
5477                   p->balance = t->balance < 0;
5478                   r->balance = -(t->balance > 0);
5479                   t->balance = 0;
5480
5481                   s = p->parent;
5482                   p->parent = t;
5483                   r->parent = t;
5484                   t->parent = s;
5485                   if (s)
5486                     {
5487                       if (s->left == p)
5488                         s->left = t;
5489                       else
5490                         s->right = t;
5491                     }
5492                   else
5493                     constructor_pending_elts = t;
5494                 }
5495               break;
5496             }
5497           else
5498             {
5499               /* p->balance == +1; growth of left side balances the node.  */
5500               p->balance = 0;
5501               break;
5502             }
5503         }
5504       else /* r == p->right */
5505         {
5506           if (p->balance == 0)
5507             /* Growth propagation from right side.  */
5508             p->balance++;
5509           else if (p->balance > 0)
5510             {
5511               if (r->balance > 0)
5512                 {
5513                   /* R rotation.  */
5514                   p->right = r->left;
5515                   if (p->right)
5516                     p->right->parent = p;
5517                   r->left = p;
5518
5519                   p->balance = 0;
5520                   r->balance = 0;
5521
5522                   s = p->parent;
5523                   p->parent = r;
5524                   r->parent = s;
5525                   if (s)
5526                     {
5527                       if (s->left == p)
5528                         s->left = r;
5529                       else
5530                         s->right = r;
5531                     }
5532                   else
5533                     constructor_pending_elts = r;
5534                 }
5535               else /* r->balance == -1 */
5536                 {
5537                   /* RL rotation */
5538                   struct init_node *t = r->left;
5539
5540                   r->left = t->right;
5541                   if (r->left)
5542                     r->left->parent = r;
5543                   t->right = r;
5544
5545                   p->right = t->left;
5546                   if (p->right)
5547                     p->right->parent = p;
5548                   t->left = p;
5549
5550                   r->balance = (t->balance < 0);
5551                   p->balance = -(t->balance > 0);
5552                   t->balance = 0;
5553
5554                   s = p->parent;
5555                   p->parent = t;
5556                   r->parent = t;
5557                   t->parent = s;
5558                   if (s)
5559                     {
5560                       if (s->left == p)
5561                         s->left = t;
5562                       else
5563                         s->right = t;
5564                     }
5565                   else
5566                     constructor_pending_elts = t;
5567                 }
5568               break;
5569             }
5570           else
5571             {
5572               /* p->balance == -1; growth of right side balances the node.  */
5573               p->balance = 0;
5574               break;
5575             }
5576         }
5577
5578       r = p;
5579       p = p->parent;
5580     }
5581 }
5582
5583 /* Build AVL tree from a sorted chain.  */
5584
5585 static void
5586 set_nonincremental_init (void)
5587 {
5588   tree chain;
5589
5590   if (TREE_CODE (constructor_type) != RECORD_TYPE
5591       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5592     return;
5593
5594   for (chain = constructor_elements; chain; chain = TREE_CHAIN (chain))
5595     add_pending_init (TREE_PURPOSE (chain), TREE_VALUE (chain));
5596   constructor_elements = 0;
5597   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5598     {
5599       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5600       /* Skip any nameless bit fields at the beginning.  */
5601       while (constructor_unfilled_fields != 0
5602              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5603              && DECL_NAME (constructor_unfilled_fields) == 0)
5604         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5605
5606     }
5607   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5608     {
5609       if (TYPE_DOMAIN (constructor_type))
5610         constructor_unfilled_index
5611             = convert (bitsizetype,
5612                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5613       else
5614         constructor_unfilled_index = bitsize_zero_node;
5615     }
5616   constructor_incremental = 0;
5617 }
5618
5619 /* Build AVL tree from a string constant.  */
5620
5621 static void
5622 set_nonincremental_init_from_string (tree str)
5623 {
5624   tree value, purpose, type;
5625   HOST_WIDE_INT val[2];
5626   const char *p, *end;
5627   int byte, wchar_bytes, charwidth, bitpos;
5628
5629   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5630
5631   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5632       == TYPE_PRECISION (char_type_node))
5633     wchar_bytes = 1;
5634   else
5635     {
5636       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5637                   == TYPE_PRECISION (wchar_type_node));
5638       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5639     }
5640   charwidth = TYPE_PRECISION (char_type_node);
5641   type = TREE_TYPE (constructor_type);
5642   p = TREE_STRING_POINTER (str);
5643   end = p + TREE_STRING_LENGTH (str);
5644
5645   for (purpose = bitsize_zero_node;
5646        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5647        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5648     {
5649       if (wchar_bytes == 1)
5650         {
5651           val[1] = (unsigned char) *p++;
5652           val[0] = 0;
5653         }
5654       else
5655         {
5656           val[0] = 0;
5657           val[1] = 0;
5658           for (byte = 0; byte < wchar_bytes; byte++)
5659             {
5660               if (BYTES_BIG_ENDIAN)
5661                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5662               else
5663                 bitpos = byte * charwidth;
5664               val[bitpos < HOST_BITS_PER_WIDE_INT]
5665                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5666                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5667             }
5668         }
5669
5670       if (!TYPE_UNSIGNED (type))
5671         {
5672           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5673           if (bitpos < HOST_BITS_PER_WIDE_INT)
5674             {
5675               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5676                 {
5677                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5678                   val[0] = -1;
5679                 }
5680             }
5681           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5682             {
5683               if (val[1] < 0)
5684                 val[0] = -1;
5685             }
5686           else if (val[0] & (((HOST_WIDE_INT) 1)
5687                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5688             val[0] |= ((HOST_WIDE_INT) -1)
5689                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5690         }
5691
5692       value = build_int_cst_wide (type, val[1], val[0]);
5693       add_pending_init (purpose, value);
5694     }
5695
5696   constructor_incremental = 0;
5697 }
5698
5699 /* Return value of FIELD in pending initializer or zero if the field was
5700    not initialized yet.  */
5701
5702 static tree
5703 find_init_member (tree field)
5704 {
5705   struct init_node *p;
5706
5707   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5708     {
5709       if (constructor_incremental
5710           && tree_int_cst_lt (field, constructor_unfilled_index))
5711         set_nonincremental_init ();
5712
5713       p = constructor_pending_elts;
5714       while (p)
5715         {
5716           if (tree_int_cst_lt (field, p->purpose))
5717             p = p->left;
5718           else if (tree_int_cst_lt (p->purpose, field))
5719             p = p->right;
5720           else
5721             return p->value;
5722         }
5723     }
5724   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5725     {
5726       tree bitpos = bit_position (field);
5727
5728       if (constructor_incremental
5729           && (!constructor_unfilled_fields
5730               || tree_int_cst_lt (bitpos,
5731                                   bit_position (constructor_unfilled_fields))))
5732         set_nonincremental_init ();
5733
5734       p = constructor_pending_elts;
5735       while (p)
5736         {
5737           if (field == p->purpose)
5738             return p->value;
5739           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5740             p = p->left;
5741           else
5742             p = p->right;
5743         }
5744     }
5745   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5746     {
5747       if (constructor_elements
5748           && TREE_PURPOSE (constructor_elements) == field)
5749         return TREE_VALUE (constructor_elements);
5750     }
5751   return 0;
5752 }
5753
5754 /* "Output" the next constructor element.
5755    At top level, really output it to assembler code now.
5756    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5757    TYPE is the data type that the containing data type wants here.
5758    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5759    If VALUE is a string constant, STRICT_STRING is true if it is
5760    unparenthesized or we should not warn here for it being parenthesized.
5761    For other types of VALUE, STRICT_STRING is not used.
5762
5763    PENDING if non-nil means output pending elements that belong
5764    right after this element.  (PENDING is normally 1;
5765    it is 0 while outputting pending elements, to avoid recursion.)  */
5766
5767 static void
5768 output_init_element (tree value, bool strict_string, tree type, tree field,
5769                      int pending)
5770 {
5771   if (type == error_mark_node || value == error_mark_node)
5772     {
5773       constructor_erroneous = 1;
5774       return;
5775     }
5776   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5777       && (TREE_CODE (value) == STRING_CST
5778           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5779       && !(TREE_CODE (value) == STRING_CST
5780            && TREE_CODE (type) == ARRAY_TYPE
5781            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5782       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5783                      TYPE_MAIN_VARIANT (type)))
5784     value = default_function_array_conversion (value);
5785
5786   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5787       && require_constant_value && !flag_isoc99 && pending)
5788     {
5789       /* As an extension, allow initializing objects with static storage
5790          duration with compound literals (which are then treated just as
5791          the brace enclosed list they contain).  */
5792       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5793       value = DECL_INITIAL (decl);
5794     }
5795
5796   if (value == error_mark_node)
5797     constructor_erroneous = 1;
5798   else if (!TREE_CONSTANT (value))
5799     constructor_constant = 0;
5800   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
5801            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5802                 || TREE_CODE (constructor_type) == UNION_TYPE)
5803                && DECL_C_BIT_FIELD (field)
5804                && TREE_CODE (value) != INTEGER_CST))
5805     constructor_simple = 0;
5806
5807   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
5808     {
5809       if (require_constant_value)
5810         {
5811           error_init ("initializer element is not constant");
5812           value = error_mark_node;
5813         }
5814       else if (require_constant_elements)
5815         pedwarn ("initializer element is not computable at load time");
5816     }
5817
5818   /* If this field is empty (and not at the end of structure),
5819      don't do anything other than checking the initializer.  */
5820   if (field
5821       && (TREE_TYPE (field) == error_mark_node
5822           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5823               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5824               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5825                   || TREE_CHAIN (field)))))
5826     return;
5827
5828   value = digest_init (type, value, strict_string, require_constant_value);
5829   if (value == error_mark_node)
5830     {
5831       constructor_erroneous = 1;
5832       return;
5833     }
5834
5835   /* If this element doesn't come next in sequence,
5836      put it on constructor_pending_elts.  */
5837   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5838       && (!constructor_incremental
5839           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5840     {
5841       if (constructor_incremental
5842           && tree_int_cst_lt (field, constructor_unfilled_index))
5843         set_nonincremental_init ();
5844
5845       add_pending_init (field, value);
5846       return;
5847     }
5848   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5849            && (!constructor_incremental
5850                || field != constructor_unfilled_fields))
5851     {
5852       /* We do this for records but not for unions.  In a union,
5853          no matter which field is specified, it can be initialized
5854          right away since it starts at the beginning of the union.  */
5855       if (constructor_incremental)
5856         {
5857           if (!constructor_unfilled_fields)
5858             set_nonincremental_init ();
5859           else
5860             {
5861               tree bitpos, unfillpos;
5862
5863               bitpos = bit_position (field);
5864               unfillpos = bit_position (constructor_unfilled_fields);
5865
5866               if (tree_int_cst_lt (bitpos, unfillpos))
5867                 set_nonincremental_init ();
5868             }
5869         }
5870
5871       add_pending_init (field, value);
5872       return;
5873     }
5874   else if (TREE_CODE (constructor_type) == UNION_TYPE
5875            && constructor_elements)
5876     {
5877       if (TREE_SIDE_EFFECTS (TREE_VALUE (constructor_elements)))
5878         warning_init ("initialized field with side-effects overwritten");
5879
5880       /* We can have just one union field set.  */
5881       constructor_elements = 0;
5882     }
5883
5884   /* Otherwise, output this element either to
5885      constructor_elements or to the assembler file.  */
5886
5887   if (field && TREE_CODE (field) == INTEGER_CST)
5888     field = copy_node (field);
5889   constructor_elements
5890     = tree_cons (field, value, constructor_elements);
5891
5892   /* Advance the variable that indicates sequential elements output.  */
5893   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5894     constructor_unfilled_index
5895       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5896                     bitsize_one_node);
5897   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5898     {
5899       constructor_unfilled_fields
5900         = TREE_CHAIN (constructor_unfilled_fields);
5901
5902       /* Skip any nameless bit fields.  */
5903       while (constructor_unfilled_fields != 0
5904              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5905              && DECL_NAME (constructor_unfilled_fields) == 0)
5906         constructor_unfilled_fields =
5907           TREE_CHAIN (constructor_unfilled_fields);
5908     }
5909   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5910     constructor_unfilled_fields = 0;
5911
5912   /* Now output any pending elements which have become next.  */
5913   if (pending)
5914     output_pending_init_elements (0);
5915 }
5916
5917 /* Output any pending elements which have become next.
5918    As we output elements, constructor_unfilled_{fields,index}
5919    advances, which may cause other elements to become next;
5920    if so, they too are output.
5921
5922    If ALL is 0, we return when there are
5923    no more pending elements to output now.
5924
5925    If ALL is 1, we output space as necessary so that
5926    we can output all the pending elements.  */
5927
5928 static void
5929 output_pending_init_elements (int all)
5930 {
5931   struct init_node *elt = constructor_pending_elts;
5932   tree next;
5933
5934  retry:
5935
5936   /* Look through the whole pending tree.
5937      If we find an element that should be output now,
5938      output it.  Otherwise, set NEXT to the element
5939      that comes first among those still pending.  */
5940
5941   next = 0;
5942   while (elt)
5943     {
5944       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5945         {
5946           if (tree_int_cst_equal (elt->purpose,
5947                                   constructor_unfilled_index))
5948             output_init_element (elt->value, true,
5949                                  TREE_TYPE (constructor_type),
5950                                  constructor_unfilled_index, 0);
5951           else if (tree_int_cst_lt (constructor_unfilled_index,
5952                                     elt->purpose))
5953             {
5954               /* Advance to the next smaller node.  */
5955               if (elt->left)
5956                 elt = elt->left;
5957               else
5958                 {
5959                   /* We have reached the smallest node bigger than the
5960                      current unfilled index.  Fill the space first.  */
5961                   next = elt->purpose;
5962                   break;
5963                 }
5964             }
5965           else
5966             {
5967               /* Advance to the next bigger node.  */
5968               if (elt->right)
5969                 elt = elt->right;
5970               else
5971                 {
5972                   /* We have reached the biggest node in a subtree.  Find
5973                      the parent of it, which is the next bigger node.  */
5974                   while (elt->parent && elt->parent->right == elt)
5975                     elt = elt->parent;
5976                   elt = elt->parent;
5977                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
5978                                               elt->purpose))
5979                     {
5980                       next = elt->purpose;
5981                       break;
5982                     }
5983                 }
5984             }
5985         }
5986       else if (TREE_CODE (constructor_type) == RECORD_TYPE
5987                || TREE_CODE (constructor_type) == UNION_TYPE)
5988         {
5989           tree ctor_unfilled_bitpos, elt_bitpos;
5990
5991           /* If the current record is complete we are done.  */
5992           if (constructor_unfilled_fields == 0)
5993             break;
5994
5995           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
5996           elt_bitpos = bit_position (elt->purpose);
5997           /* We can't compare fields here because there might be empty
5998              fields in between.  */
5999           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6000             {
6001               constructor_unfilled_fields = elt->purpose;
6002               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6003                                    elt->purpose, 0);
6004             }
6005           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6006             {
6007               /* Advance to the next smaller node.  */
6008               if (elt->left)
6009                 elt = elt->left;
6010               else
6011                 {
6012                   /* We have reached the smallest node bigger than the
6013                      current unfilled field.  Fill the space first.  */
6014                   next = elt->purpose;
6015                   break;
6016                 }
6017             }
6018           else
6019             {
6020               /* Advance to the next bigger node.  */
6021               if (elt->right)
6022                 elt = elt->right;
6023               else
6024                 {
6025                   /* We have reached the biggest node in a subtree.  Find
6026                      the parent of it, which is the next bigger node.  */
6027                   while (elt->parent && elt->parent->right == elt)
6028                     elt = elt->parent;
6029                   elt = elt->parent;
6030                   if (elt
6031                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6032                                            bit_position (elt->purpose))))
6033                     {
6034                       next = elt->purpose;
6035                       break;
6036                     }
6037                 }
6038             }
6039         }
6040     }
6041
6042   /* Ordinarily return, but not if we want to output all
6043      and there are elements left.  */
6044   if (!(all && next != 0))
6045     return;
6046
6047   /* If it's not incremental, just skip over the gap, so that after
6048      jumping to retry we will output the next successive element.  */
6049   if (TREE_CODE (constructor_type) == RECORD_TYPE
6050       || TREE_CODE (constructor_type) == UNION_TYPE)
6051     constructor_unfilled_fields = next;
6052   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6053     constructor_unfilled_index = next;
6054
6055   /* ELT now points to the node in the pending tree with the next
6056      initializer to output.  */
6057   goto retry;
6058 }
6059 \f
6060 /* Add one non-braced element to the current constructor level.
6061    This adjusts the current position within the constructor's type.
6062    This may also start or terminate implicit levels
6063    to handle a partly-braced initializer.
6064
6065    Once this has found the correct level for the new element,
6066    it calls output_init_element.  */
6067
6068 void
6069 process_init_element (struct c_expr value)
6070 {
6071   tree orig_value = value.value;
6072   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6073   bool strict_string = value.original_code == STRING_CST;
6074
6075   designator_depth = 0;
6076   designator_errorneous = 0;
6077
6078   /* Handle superfluous braces around string cst as in
6079      char x[] = {"foo"}; */
6080   if (string_flag
6081       && constructor_type
6082       && TREE_CODE (constructor_type) == ARRAY_TYPE
6083       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6084       && integer_zerop (constructor_unfilled_index))
6085     {
6086       if (constructor_stack->replacement_value.value)
6087         error_init ("excess elements in char array initializer");
6088       constructor_stack->replacement_value = value;
6089       return;
6090     }
6091
6092   if (constructor_stack->replacement_value.value != 0)
6093     {
6094       error_init ("excess elements in struct initializer");
6095       return;
6096     }
6097
6098   /* Ignore elements of a brace group if it is entirely superfluous
6099      and has already been diagnosed.  */
6100   if (constructor_type == 0)
6101     return;
6102
6103   /* If we've exhausted any levels that didn't have braces,
6104      pop them now.  */
6105   while (constructor_stack->implicit)
6106     {
6107       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6108            || TREE_CODE (constructor_type) == UNION_TYPE)
6109           && constructor_fields == 0)
6110         process_init_element (pop_init_level (1));
6111       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6112                && (constructor_max_index == 0
6113                    || tree_int_cst_lt (constructor_max_index,
6114                                        constructor_index)))
6115         process_init_element (pop_init_level (1));
6116       else
6117         break;
6118     }
6119
6120   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6121   if (constructor_range_stack)
6122     {
6123       /* If value is a compound literal and we'll be just using its
6124          content, don't put it into a SAVE_EXPR.  */
6125       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6126           || !require_constant_value
6127           || flag_isoc99)
6128         value.value = save_expr (value.value);
6129     }
6130
6131   while (1)
6132     {
6133       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6134         {
6135           tree fieldtype;
6136           enum tree_code fieldcode;
6137
6138           if (constructor_fields == 0)
6139             {
6140               pedwarn_init ("excess elements in struct initializer");
6141               break;
6142             }
6143
6144           fieldtype = TREE_TYPE (constructor_fields);
6145           if (fieldtype != error_mark_node)
6146             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6147           fieldcode = TREE_CODE (fieldtype);
6148
6149           /* Error for non-static initialization of a flexible array member.  */
6150           if (fieldcode == ARRAY_TYPE
6151               && !require_constant_value
6152               && TYPE_SIZE (fieldtype) == NULL_TREE
6153               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6154             {
6155               error_init ("non-static initialization of a flexible array member");
6156               break;
6157             }
6158
6159           /* Accept a string constant to initialize a subarray.  */
6160           if (value.value != 0
6161               && fieldcode == ARRAY_TYPE
6162               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6163               && string_flag)
6164             value.value = orig_value;
6165           /* Otherwise, if we have come to a subaggregate,
6166              and we don't have an element of its type, push into it.  */
6167           else if (value.value != 0
6168                    && value.value != error_mark_node
6169                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6170                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6171                        || fieldcode == UNION_TYPE))
6172             {
6173               push_init_level (1);
6174               continue;
6175             }
6176
6177           if (value.value)
6178             {
6179               push_member_name (constructor_fields);
6180               output_init_element (value.value, strict_string,
6181                                    fieldtype, constructor_fields, 1);
6182               RESTORE_SPELLING_DEPTH (constructor_depth);
6183             }
6184           else
6185             /* Do the bookkeeping for an element that was
6186                directly output as a constructor.  */
6187             {
6188               /* For a record, keep track of end position of last field.  */
6189               if (DECL_SIZE (constructor_fields))
6190                 constructor_bit_index
6191                   = size_binop (PLUS_EXPR,
6192                                 bit_position (constructor_fields),
6193                                 DECL_SIZE (constructor_fields));
6194
6195               /* If the current field was the first one not yet written out,
6196                  it isn't now, so update.  */
6197               if (constructor_unfilled_fields == constructor_fields)
6198                 {
6199                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6200                   /* Skip any nameless bit fields.  */
6201                   while (constructor_unfilled_fields != 0
6202                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6203                          && DECL_NAME (constructor_unfilled_fields) == 0)
6204                     constructor_unfilled_fields =
6205                       TREE_CHAIN (constructor_unfilled_fields);
6206                 }
6207             }
6208
6209           constructor_fields = TREE_CHAIN (constructor_fields);
6210           /* Skip any nameless bit fields at the beginning.  */
6211           while (constructor_fields != 0
6212                  && DECL_C_BIT_FIELD (constructor_fields)
6213                  && DECL_NAME (constructor_fields) == 0)
6214             constructor_fields = TREE_CHAIN (constructor_fields);
6215         }
6216       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6217         {
6218           tree fieldtype;
6219           enum tree_code fieldcode;
6220
6221           if (constructor_fields == 0)
6222             {
6223               pedwarn_init ("excess elements in union initializer");
6224               break;
6225             }
6226
6227           fieldtype = TREE_TYPE (constructor_fields);
6228           if (fieldtype != error_mark_node)
6229             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6230           fieldcode = TREE_CODE (fieldtype);
6231
6232           /* Warn that traditional C rejects initialization of unions.
6233              We skip the warning if the value is zero.  This is done
6234              under the assumption that the zero initializer in user
6235              code appears conditioned on e.g. __STDC__ to avoid
6236              "missing initializer" warnings and relies on default
6237              initialization to zero in the traditional C case.
6238              We also skip the warning if the initializer is designated,
6239              again on the assumption that this must be conditional on
6240              __STDC__ anyway (and we've already complained about the
6241              member-designator already).  */
6242           if (warn_traditional && !in_system_header && !constructor_designated
6243               && !(value.value && (integer_zerop (value.value)
6244                                    || real_zerop (value.value))))
6245             warning (0, "traditional C rejects initialization of unions");
6246
6247           /* Accept a string constant to initialize a subarray.  */
6248           if (value.value != 0
6249               && fieldcode == ARRAY_TYPE
6250               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6251               && string_flag)
6252             value.value = orig_value;
6253           /* Otherwise, if we have come to a subaggregate,
6254              and we don't have an element of its type, push into it.  */
6255           else if (value.value != 0
6256                    && value.value != error_mark_node
6257                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6258                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6259                        || fieldcode == UNION_TYPE))
6260             {
6261               push_init_level (1);
6262               continue;
6263             }
6264
6265           if (value.value)
6266             {
6267               push_member_name (constructor_fields);
6268               output_init_element (value.value, strict_string,
6269                                    fieldtype, constructor_fields, 1);
6270               RESTORE_SPELLING_DEPTH (constructor_depth);
6271             }
6272           else
6273             /* Do the bookkeeping for an element that was
6274                directly output as a constructor.  */
6275             {
6276               constructor_bit_index = DECL_SIZE (constructor_fields);
6277               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6278             }
6279
6280           constructor_fields = 0;
6281         }
6282       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6283         {
6284           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6285           enum tree_code eltcode = TREE_CODE (elttype);
6286
6287           /* Accept a string constant to initialize a subarray.  */
6288           if (value.value != 0
6289               && eltcode == ARRAY_TYPE
6290               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6291               && string_flag)
6292             value.value = orig_value;
6293           /* Otherwise, if we have come to a subaggregate,
6294              and we don't have an element of its type, push into it.  */
6295           else if (value.value != 0
6296                    && value.value != error_mark_node
6297                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6298                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6299                        || eltcode == UNION_TYPE))
6300             {
6301               push_init_level (1);
6302               continue;
6303             }
6304
6305           if (constructor_max_index != 0
6306               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6307                   || integer_all_onesp (constructor_max_index)))
6308             {
6309               pedwarn_init ("excess elements in array initializer");
6310               break;
6311             }
6312
6313           /* Now output the actual element.  */
6314           if (value.value)
6315             {
6316               push_array_bounds (tree_low_cst (constructor_index, 0));
6317               output_init_element (value.value, strict_string,
6318                                    elttype, constructor_index, 1);
6319               RESTORE_SPELLING_DEPTH (constructor_depth);
6320             }
6321
6322           constructor_index
6323             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6324
6325           if (!value.value)
6326             /* If we are doing the bookkeeping for an element that was
6327                directly output as a constructor, we must update
6328                constructor_unfilled_index.  */
6329             constructor_unfilled_index = constructor_index;
6330         }
6331       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6332         {
6333           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6334
6335          /* Do a basic check of initializer size.  Note that vectors
6336             always have a fixed size derived from their type.  */
6337           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6338             {
6339               pedwarn_init ("excess elements in vector initializer");
6340               break;
6341             }
6342
6343           /* Now output the actual element.  */
6344           if (value.value)
6345             output_init_element (value.value, strict_string,
6346                                  elttype, constructor_index, 1);
6347
6348           constructor_index
6349             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6350
6351           if (!value.value)
6352             /* If we are doing the bookkeeping for an element that was
6353                directly output as a constructor, we must update
6354                constructor_unfilled_index.  */
6355             constructor_unfilled_index = constructor_index;
6356         }
6357
6358       /* Handle the sole element allowed in a braced initializer
6359          for a scalar variable.  */
6360       else if (constructor_type != error_mark_node
6361                && constructor_fields == 0)
6362         {
6363           pedwarn_init ("excess elements in scalar initializer");
6364           break;
6365         }
6366       else
6367         {
6368           if (value.value)
6369             output_init_element (value.value, strict_string,
6370                                  constructor_type, NULL_TREE, 1);
6371           constructor_fields = 0;
6372         }
6373
6374       /* Handle range initializers either at this level or anywhere higher
6375          in the designator stack.  */
6376       if (constructor_range_stack)
6377         {
6378           struct constructor_range_stack *p, *range_stack;
6379           int finish = 0;
6380
6381           range_stack = constructor_range_stack;
6382           constructor_range_stack = 0;
6383           while (constructor_stack != range_stack->stack)
6384             {
6385               gcc_assert (constructor_stack->implicit);
6386               process_init_element (pop_init_level (1));
6387             }
6388           for (p = range_stack;
6389                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6390                p = p->prev)
6391             {
6392               gcc_assert (constructor_stack->implicit);
6393               process_init_element (pop_init_level (1));
6394             }
6395
6396           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6397           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6398             finish = 1;
6399
6400           while (1)
6401             {
6402               constructor_index = p->index;
6403               constructor_fields = p->fields;
6404               if (finish && p->range_end && p->index == p->range_start)
6405                 {
6406                   finish = 0;
6407                   p->prev = 0;
6408                 }
6409               p = p->next;
6410               if (!p)
6411                 break;
6412               push_init_level (2);
6413               p->stack = constructor_stack;
6414               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6415                 p->index = p->range_start;
6416             }
6417
6418           if (!finish)
6419             constructor_range_stack = range_stack;
6420           continue;
6421         }
6422
6423       break;
6424     }
6425
6426   constructor_range_stack = 0;
6427 }
6428 \f
6429 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6430    (guaranteed to be 'volatile' or null) and ARGS (represented using
6431    an ASM_EXPR node).  */
6432 tree
6433 build_asm_stmt (tree cv_qualifier, tree args)
6434 {
6435   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6436     ASM_VOLATILE_P (args) = 1;
6437   return add_stmt (args);
6438 }
6439
6440 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6441    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6442    SIMPLE indicates whether there was anything at all after the
6443    string in the asm expression -- asm("blah") and asm("blah" : )
6444    are subtly different.  We use a ASM_EXPR node to represent this.  */
6445 tree
6446 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6447                 bool simple)
6448 {
6449   tree tail;
6450   tree args;
6451   int i;
6452   const char *constraint;
6453   const char **oconstraints;
6454   bool allows_mem, allows_reg, is_inout;
6455   int ninputs, noutputs;
6456
6457   ninputs = list_length (inputs);
6458   noutputs = list_length (outputs);
6459   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6460
6461   string = resolve_asm_operand_names (string, outputs, inputs);
6462
6463   /* Remove output conversions that change the type but not the mode.  */
6464   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6465     {
6466       tree output = TREE_VALUE (tail);
6467
6468       /* ??? Really, this should not be here.  Users should be using a
6469          proper lvalue, dammit.  But there's a long history of using casts
6470          in the output operands.  In cases like longlong.h, this becomes a
6471          primitive form of typechecking -- if the cast can be removed, then
6472          the output operand had a type of the proper width; otherwise we'll
6473          get an error.  Gross, but ...  */
6474       STRIP_NOPS (output);
6475
6476       if (!lvalue_or_else (output, lv_asm))
6477         output = error_mark_node;
6478
6479       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6480       oconstraints[i] = constraint;
6481
6482       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6483                                    &allows_mem, &allows_reg, &is_inout))
6484         {
6485           /* If the operand is going to end up in memory,
6486              mark it addressable.  */
6487           if (!allows_reg && !c_mark_addressable (output))
6488             output = error_mark_node;
6489         }
6490       else
6491         output = error_mark_node;
6492
6493       TREE_VALUE (tail) = output;
6494     }
6495
6496   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6497     {
6498       tree input;
6499
6500       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6501       input = TREE_VALUE (tail);
6502
6503       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6504                                   oconstraints, &allows_mem, &allows_reg))
6505         {
6506           /* If the operand is going to end up in memory,
6507              mark it addressable.  */
6508           if (!allows_reg && allows_mem)
6509             {
6510               /* Strip the nops as we allow this case.  FIXME, this really
6511                  should be rejected or made deprecated.  */
6512               STRIP_NOPS (input);
6513               if (!c_mark_addressable (input))
6514                 input = error_mark_node;
6515           }
6516         }
6517       else
6518         input = error_mark_node;
6519
6520       TREE_VALUE (tail) = input;
6521     }
6522
6523   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6524
6525   /* Simple asm statements are treated as volatile.  */
6526   if (simple)
6527     {
6528       ASM_VOLATILE_P (args) = 1;
6529       ASM_INPUT_P (args) = 1;
6530     }
6531
6532   return args;
6533 }
6534 \f
6535 /* Generate a goto statement to LABEL.  */
6536
6537 tree
6538 c_finish_goto_label (tree label)
6539 {
6540   tree decl = lookup_label (label);
6541   if (!decl)
6542     return NULL_TREE;
6543
6544   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6545     {
6546       error ("jump into statement expression");
6547       return NULL_TREE;
6548     }
6549
6550   if (C_DECL_UNJUMPABLE_VM (decl))
6551     {
6552       error ("jump into scope of identifier with variably modified type");
6553       return NULL_TREE;
6554     }
6555
6556   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6557     {
6558       /* No jump from outside this statement expression context, so
6559          record that there is a jump from within this context.  */
6560       struct c_label_list *nlist;
6561       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6562       nlist->next = label_context_stack_se->labels_used;
6563       nlist->label = decl;
6564       label_context_stack_se->labels_used = nlist;
6565     }
6566
6567   if (!C_DECL_UNDEFINABLE_VM (decl))
6568     {
6569       /* No jump from outside this context context of identifiers with
6570          variably modified type, so record that there is a jump from
6571          within this context.  */
6572       struct c_label_list *nlist;
6573       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6574       nlist->next = label_context_stack_vm->labels_used;
6575       nlist->label = decl;
6576       label_context_stack_vm->labels_used = nlist;
6577     }
6578
6579   TREE_USED (decl) = 1;
6580   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6581 }
6582
6583 /* Generate a computed goto statement to EXPR.  */
6584
6585 tree
6586 c_finish_goto_ptr (tree expr)
6587 {
6588   if (pedantic)
6589     pedwarn ("ISO C forbids %<goto *expr;%>");
6590   expr = convert (ptr_type_node, expr);
6591   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6592 }
6593
6594 /* Generate a C `return' statement.  RETVAL is the expression for what
6595    to return, or a null pointer for `return;' with no value.  */
6596
6597 tree
6598 c_finish_return (tree retval)
6599 {
6600   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6601
6602   if (TREE_THIS_VOLATILE (current_function_decl))
6603     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6604
6605   if (!retval)
6606     {
6607       current_function_returns_null = 1;
6608       if ((warn_return_type || flag_isoc99)
6609           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6610         pedwarn_c99 ("%<return%> with no value, in "
6611                      "function returning non-void");
6612     }
6613   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6614     {
6615       current_function_returns_null = 1;
6616       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6617         pedwarn ("%<return%> with a value, in function returning void");
6618     }
6619   else
6620     {
6621       tree t = convert_for_assignment (valtype, retval, ic_return,
6622                                        NULL_TREE, NULL_TREE, 0);
6623       tree res = DECL_RESULT (current_function_decl);
6624       tree inner;
6625
6626       current_function_returns_value = 1;
6627       if (t == error_mark_node)
6628         return NULL_TREE;
6629
6630       inner = t = convert (TREE_TYPE (res), t);
6631
6632       /* Strip any conversions, additions, and subtractions, and see if
6633          we are returning the address of a local variable.  Warn if so.  */
6634       while (1)
6635         {
6636           switch (TREE_CODE (inner))
6637             {
6638             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6639             case PLUS_EXPR:
6640               inner = TREE_OPERAND (inner, 0);
6641               continue;
6642
6643             case MINUS_EXPR:
6644               /* If the second operand of the MINUS_EXPR has a pointer
6645                  type (or is converted from it), this may be valid, so
6646                  don't give a warning.  */
6647               {
6648                 tree op1 = TREE_OPERAND (inner, 1);
6649
6650                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6651                        && (TREE_CODE (op1) == NOP_EXPR
6652                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6653                            || TREE_CODE (op1) == CONVERT_EXPR))
6654                   op1 = TREE_OPERAND (op1, 0);
6655
6656                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6657                   break;
6658
6659                 inner = TREE_OPERAND (inner, 0);
6660                 continue;
6661               }
6662
6663             case ADDR_EXPR:
6664               inner = TREE_OPERAND (inner, 0);
6665
6666               while (REFERENCE_CLASS_P (inner)
6667                      && TREE_CODE (inner) != INDIRECT_REF)
6668                 inner = TREE_OPERAND (inner, 0);
6669
6670               if (DECL_P (inner)
6671                   && !DECL_EXTERNAL (inner)
6672                   && !TREE_STATIC (inner)
6673                   && DECL_CONTEXT (inner) == current_function_decl)
6674                 warning (0, "function returns address of local variable");
6675               break;
6676
6677             default:
6678               break;
6679             }
6680
6681           break;
6682         }
6683
6684       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6685     }
6686
6687   return add_stmt (build_stmt (RETURN_EXPR, retval));
6688 }
6689 \f
6690 struct c_switch {
6691   /* The SWITCH_EXPR being built.  */
6692   tree switch_expr;
6693
6694   /* The original type of the testing expression, i.e. before the
6695      default conversion is applied.  */
6696   tree orig_type;
6697
6698   /* A splay-tree mapping the low element of a case range to the high
6699      element, or NULL_TREE if there is no high element.  Used to
6700      determine whether or not a new case label duplicates an old case
6701      label.  We need a tree, rather than simply a hash table, because
6702      of the GNU case range extension.  */
6703   splay_tree cases;
6704
6705   /* Number of nested statement expressions within this switch
6706      statement; if nonzero, case and default labels may not
6707      appear.  */
6708   unsigned int blocked_stmt_expr;
6709
6710   /* Scope of outermost declarations of identifiers with variably
6711      modified type within this switch statement; if nonzero, case and
6712      default labels may not appear.  */
6713   unsigned int blocked_vm;
6714
6715   /* The next node on the stack.  */
6716   struct c_switch *next;
6717 };
6718
6719 /* A stack of the currently active switch statements.  The innermost
6720    switch statement is on the top of the stack.  There is no need to
6721    mark the stack for garbage collection because it is only active
6722    during the processing of the body of a function, and we never
6723    collect at that point.  */
6724
6725 struct c_switch *c_switch_stack;
6726
6727 /* Start a C switch statement, testing expression EXP.  Return the new
6728    SWITCH_EXPR.  */
6729
6730 tree
6731 c_start_case (tree exp)
6732 {
6733   enum tree_code code;
6734   tree type, orig_type = error_mark_node;
6735   struct c_switch *cs;
6736
6737   if (exp != error_mark_node)
6738     {
6739       code = TREE_CODE (TREE_TYPE (exp));
6740       orig_type = TREE_TYPE (exp);
6741
6742       if (!INTEGRAL_TYPE_P (orig_type)
6743           && code != ERROR_MARK)
6744         {
6745           error ("switch quantity not an integer");
6746           exp = integer_zero_node;
6747           orig_type = error_mark_node;
6748         }
6749       else
6750         {
6751           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6752
6753           if (warn_traditional && !in_system_header
6754               && (type == long_integer_type_node
6755                   || type == long_unsigned_type_node))
6756             warning (0, "%<long%> switch expression not converted to "
6757                      "%<int%> in ISO C");
6758
6759           exp = default_conversion (exp);
6760           type = TREE_TYPE (exp);
6761         }
6762     }
6763
6764   /* Add this new SWITCH_EXPR to the stack.  */
6765   cs = XNEW (struct c_switch);
6766   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6767   cs->orig_type = orig_type;
6768   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6769   cs->blocked_stmt_expr = 0;
6770   cs->blocked_vm = 0;
6771   cs->next = c_switch_stack;
6772   c_switch_stack = cs;
6773
6774   return add_stmt (cs->switch_expr);
6775 }
6776
6777 /* Process a case label.  */
6778
6779 tree
6780 do_case (tree low_value, tree high_value)
6781 {
6782   tree label = NULL_TREE;
6783
6784   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
6785       && !c_switch_stack->blocked_vm)
6786     {
6787       label = c_add_case_label (c_switch_stack->cases,
6788                                 SWITCH_COND (c_switch_stack->switch_expr),
6789                                 c_switch_stack->orig_type,
6790                                 low_value, high_value);
6791       if (label == error_mark_node)
6792         label = NULL_TREE;
6793     }
6794   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
6795     {
6796       if (low_value)
6797         error ("case label in statement expression not containing "
6798                "enclosing switch statement");
6799       else
6800         error ("%<default%> label in statement expression not containing "
6801                "enclosing switch statement");
6802     }
6803   else if (c_switch_stack && c_switch_stack->blocked_vm)
6804     {
6805       if (low_value)
6806         error ("case label in scope of identifier with variably modified "
6807                "type not containing enclosing switch statement");
6808       else
6809         error ("%<default%> label in scope of identifier with variably "
6810                "modified type not containing enclosing switch statement");
6811     }
6812   else if (low_value)
6813     error ("case label not within a switch statement");
6814   else
6815     error ("%<default%> label not within a switch statement");
6816
6817   return label;
6818 }
6819
6820 /* Finish the switch statement.  */
6821
6822 void
6823 c_finish_case (tree body)
6824 {
6825   struct c_switch *cs = c_switch_stack;
6826   location_t switch_location;
6827
6828   SWITCH_BODY (cs->switch_expr) = body;
6829
6830   /* We must not be within a statement expression nested in the switch
6831      at this point; we might, however, be within the scope of an
6832      identifier with variably modified type nested in the switch.  */
6833   gcc_assert (!cs->blocked_stmt_expr);
6834
6835   /* Emit warnings as needed.  */
6836   if (EXPR_HAS_LOCATION (cs->switch_expr))
6837     switch_location = EXPR_LOCATION (cs->switch_expr);
6838   else
6839     switch_location = input_location;
6840   c_do_switch_warnings (cs->cases, switch_location,
6841                         TREE_TYPE (cs->switch_expr),
6842                         SWITCH_COND (cs->switch_expr));
6843
6844   /* Pop the stack.  */
6845   c_switch_stack = cs->next;
6846   splay_tree_delete (cs->cases);
6847   XDELETE (cs);
6848 }
6849 \f
6850 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6851    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6852    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6853    statement, and was not surrounded with parenthesis.  */
6854
6855 void
6856 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6857                   tree else_block, bool nested_if)
6858 {
6859   tree stmt;
6860
6861   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6862   if (warn_parentheses && nested_if && else_block == NULL)
6863     {
6864       tree inner_if = then_block;
6865
6866       /* We know from the grammar productions that there is an IF nested
6867          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6868          it might not be exactly THEN_BLOCK, but should be the last
6869          non-container statement within.  */
6870       while (1)
6871         switch (TREE_CODE (inner_if))
6872           {
6873           case COND_EXPR:
6874             goto found;
6875           case BIND_EXPR:
6876             inner_if = BIND_EXPR_BODY (inner_if);
6877             break;
6878           case STATEMENT_LIST:
6879             inner_if = expr_last (then_block);
6880             break;
6881           case TRY_FINALLY_EXPR:
6882           case TRY_CATCH_EXPR:
6883             inner_if = TREE_OPERAND (inner_if, 0);
6884             break;
6885           default:
6886             gcc_unreachable ();
6887           }
6888     found:
6889
6890       if (COND_EXPR_ELSE (inner_if))
6891          warning (0, "%Hsuggest explicit braces to avoid ambiguous %<else%>",
6892                   &if_locus);
6893     }
6894
6895   /* Diagnose ";" via the special empty statement node that we create.  */
6896   if (extra_warnings)
6897     {
6898       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
6899         {
6900           if (!else_block)
6901             warning (0, "%Hempty body in an if-statement",
6902                      EXPR_LOCUS (then_block));
6903           then_block = alloc_stmt_list ();
6904         }
6905       if (else_block
6906           && TREE_CODE (else_block) == NOP_EXPR
6907           && !TREE_TYPE (else_block))
6908         {
6909           warning (0, "%Hempty body in an else-statement",
6910                    EXPR_LOCUS (else_block));
6911           else_block = alloc_stmt_list ();
6912         }
6913     }
6914
6915   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
6916   SET_EXPR_LOCATION (stmt, if_locus);
6917   add_stmt (stmt);
6918 }
6919
6920 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
6921    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
6922    is false for DO loops.  INCR is the FOR increment expression.  BODY is
6923    the statement controlled by the loop.  BLAB is the break label.  CLAB is
6924    the continue label.  Everything is allowed to be NULL.  */
6925
6926 void
6927 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
6928                tree blab, tree clab, bool cond_is_first)
6929 {
6930   tree entry = NULL, exit = NULL, t;
6931
6932   /* If the condition is zero don't generate a loop construct.  */
6933   if (cond && integer_zerop (cond))
6934     {
6935       if (cond_is_first)
6936         {
6937           t = build_and_jump (&blab);
6938           SET_EXPR_LOCATION (t, start_locus);
6939           add_stmt (t);
6940         }
6941     }
6942   else
6943     {
6944       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6945
6946       /* If we have an exit condition, then we build an IF with gotos either
6947          out of the loop, or to the top of it.  If there's no exit condition,
6948          then we just build a jump back to the top.  */
6949       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
6950
6951       if (cond && !integer_nonzerop (cond))
6952         {
6953           /* Canonicalize the loop condition to the end.  This means
6954              generating a branch to the loop condition.  Reuse the
6955              continue label, if possible.  */
6956           if (cond_is_first)
6957             {
6958               if (incr || !clab)
6959                 {
6960                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6961                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
6962                 }
6963               else
6964                 t = build1 (GOTO_EXPR, void_type_node, clab);
6965               SET_EXPR_LOCATION (t, start_locus);
6966               add_stmt (t);
6967             }
6968
6969           t = build_and_jump (&blab);
6970           exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
6971           exit = fold (exit);
6972           if (cond_is_first)
6973             SET_EXPR_LOCATION (exit, start_locus);
6974           else
6975             SET_EXPR_LOCATION (exit, input_location);
6976         }
6977
6978       add_stmt (top);
6979     }
6980
6981   if (body)
6982     add_stmt (body);
6983   if (clab)
6984     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
6985   if (incr)
6986     add_stmt (incr);
6987   if (entry)
6988     add_stmt (entry);
6989   if (exit)
6990     add_stmt (exit);
6991   if (blab)
6992     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
6993 }
6994
6995 tree
6996 c_finish_bc_stmt (tree *label_p, bool is_break)
6997 {
6998   bool skip;
6999   tree label = *label_p;
7000
7001   /* In switch statements break is sometimes stylistically used after
7002      a return statement.  This can lead to spurious warnings about
7003      control reaching the end of a non-void function when it is
7004      inlined.  Note that we are calling block_may_fallthru with
7005      language specific tree nodes; this works because
7006      block_may_fallthru returns true when given something it does not
7007      understand.  */
7008   skip = !block_may_fallthru (cur_stmt_list);
7009
7010   if (!label)
7011     {
7012       if (!skip)
7013         *label_p = label = create_artificial_label ();
7014     }
7015   else if (TREE_CODE (label) != LABEL_DECL)
7016     {
7017       if (is_break)
7018         error ("break statement not within loop or switch");
7019       else
7020         error ("continue statement not within a loop");
7021       return NULL_TREE;
7022     }
7023
7024   if (skip)
7025     return NULL_TREE;
7026
7027   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7028 }
7029
7030 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7031
7032 static void
7033 emit_side_effect_warnings (tree expr)
7034 {
7035   if (expr == error_mark_node)
7036     ;
7037   else if (!TREE_SIDE_EFFECTS (expr))
7038     {
7039       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7040         warning (0, "%Hstatement with no effect",
7041                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7042     }
7043   else if (warn_unused_value)
7044     warn_if_unused_value (expr, input_location);
7045 }
7046
7047 /* Process an expression as if it were a complete statement.  Emit
7048    diagnostics, but do not call ADD_STMT.  */
7049
7050 tree
7051 c_process_expr_stmt (tree expr)
7052 {
7053   if (!expr)
7054     return NULL_TREE;
7055
7056   if (warn_sequence_point)
7057     verify_sequence_points (expr);
7058
7059   if (TREE_TYPE (expr) != error_mark_node
7060       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7061       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7062     error ("expression statement has incomplete type");
7063
7064   /* If we're not processing a statement expression, warn about unused values.
7065      Warnings for statement expressions will be emitted later, once we figure
7066      out which is the result.  */
7067   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7068       && (extra_warnings || warn_unused_value))
7069     emit_side_effect_warnings (expr);
7070
7071   /* If the expression is not of a type to which we cannot assign a line
7072      number, wrap the thing in a no-op NOP_EXPR.  */
7073   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7074     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7075
7076   if (EXPR_P (expr))
7077     SET_EXPR_LOCATION (expr, input_location);
7078
7079   return expr;
7080 }
7081
7082 /* Emit an expression as a statement.  */
7083
7084 tree
7085 c_finish_expr_stmt (tree expr)
7086 {
7087   if (expr)
7088     return add_stmt (c_process_expr_stmt (expr));
7089   else
7090     return NULL;
7091 }
7092
7093 /* Do the opposite and emit a statement as an expression.  To begin,
7094    create a new binding level and return it.  */
7095
7096 tree
7097 c_begin_stmt_expr (void)
7098 {
7099   tree ret;
7100   struct c_label_context_se *nstack;
7101   struct c_label_list *glist;
7102
7103   /* We must force a BLOCK for this level so that, if it is not expanded
7104      later, there is a way to turn off the entire subtree of blocks that
7105      are contained in it.  */
7106   keep_next_level ();
7107   ret = c_begin_compound_stmt (true);
7108   if (c_switch_stack)
7109     {
7110       c_switch_stack->blocked_stmt_expr++;
7111       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7112     }
7113   for (glist = label_context_stack_se->labels_used;
7114        glist != NULL;
7115        glist = glist->next)
7116     {
7117       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7118     }
7119   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7120   nstack->labels_def = NULL;
7121   nstack->labels_used = NULL;
7122   nstack->next = label_context_stack_se;
7123   label_context_stack_se = nstack;
7124
7125   /* Mark the current statement list as belonging to a statement list.  */
7126   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7127
7128   return ret;
7129 }
7130
7131 tree
7132 c_finish_stmt_expr (tree body)
7133 {
7134   tree last, type, tmp, val;
7135   tree *last_p;
7136   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7137
7138   body = c_end_compound_stmt (body, true);
7139   if (c_switch_stack)
7140     {
7141       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7142       c_switch_stack->blocked_stmt_expr--;
7143     }
7144   /* It is no longer possible to jump to labels defined within this
7145      statement expression.  */
7146   for (dlist = label_context_stack_se->labels_def;
7147        dlist != NULL;
7148        dlist = dlist->next)
7149     {
7150       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7151     }
7152   /* It is again possible to define labels with a goto just outside
7153      this statement expression.  */
7154   for (glist = label_context_stack_se->next->labels_used;
7155        glist != NULL;
7156        glist = glist->next)
7157     {
7158       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7159       glist_prev = glist;
7160     }
7161   if (glist_prev != NULL)
7162     glist_prev->next = label_context_stack_se->labels_used;
7163   else
7164     label_context_stack_se->next->labels_used
7165       = label_context_stack_se->labels_used;
7166   label_context_stack_se = label_context_stack_se->next;
7167
7168   /* Locate the last statement in BODY.  See c_end_compound_stmt
7169      about always returning a BIND_EXPR.  */
7170   last_p = &BIND_EXPR_BODY (body);
7171   last = BIND_EXPR_BODY (body);
7172
7173  continue_searching:
7174   if (TREE_CODE (last) == STATEMENT_LIST)
7175     {
7176       tree_stmt_iterator i;
7177
7178       /* This can happen with degenerate cases like ({ }).  No value.  */
7179       if (!TREE_SIDE_EFFECTS (last))
7180         return body;
7181
7182       /* If we're supposed to generate side effects warnings, process
7183          all of the statements except the last.  */
7184       if (extra_warnings || warn_unused_value)
7185         {
7186           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7187             emit_side_effect_warnings (tsi_stmt (i));
7188         }
7189       else
7190         i = tsi_last (last);
7191       last_p = tsi_stmt_ptr (i);
7192       last = *last_p;
7193     }
7194
7195   /* If the end of the list is exception related, then the list was split
7196      by a call to push_cleanup.  Continue searching.  */
7197   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7198       || TREE_CODE (last) == TRY_CATCH_EXPR)
7199     {
7200       last_p = &TREE_OPERAND (last, 0);
7201       last = *last_p;
7202       goto continue_searching;
7203     }
7204
7205   /* In the case that the BIND_EXPR is not necessary, return the
7206      expression out from inside it.  */
7207   if (last == error_mark_node
7208       || (last == BIND_EXPR_BODY (body)
7209           && BIND_EXPR_VARS (body) == NULL))
7210     return last;
7211
7212   /* Extract the type of said expression.  */
7213   type = TREE_TYPE (last);
7214
7215   /* If we're not returning a value at all, then the BIND_EXPR that
7216      we already have is a fine expression to return.  */
7217   if (!type || VOID_TYPE_P (type))
7218     return body;
7219
7220   /* Now that we've located the expression containing the value, it seems
7221      silly to make voidify_wrapper_expr repeat the process.  Create a
7222      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7223   tmp = create_tmp_var_raw (type, NULL);
7224
7225   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7226      tree_expr_nonnegative_p giving up immediately.  */
7227   val = last;
7228   if (TREE_CODE (val) == NOP_EXPR
7229       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7230     val = TREE_OPERAND (val, 0);
7231
7232   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7233   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7234
7235   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7236 }
7237
7238 /* Begin the scope of an identifier of variably modified type, scope
7239    number SCOPE.  Jumping from outside this scope to inside it is not
7240    permitted.  */
7241
7242 void
7243 c_begin_vm_scope (unsigned int scope)
7244 {
7245   struct c_label_context_vm *nstack;
7246   struct c_label_list *glist;
7247
7248   gcc_assert (scope > 0);
7249   if (c_switch_stack && !c_switch_stack->blocked_vm)
7250     c_switch_stack->blocked_vm = scope;
7251   for (glist = label_context_stack_vm->labels_used;
7252        glist != NULL;
7253        glist = glist->next)
7254     {
7255       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7256     }
7257   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7258   nstack->labels_def = NULL;
7259   nstack->labels_used = NULL;
7260   nstack->scope = scope;
7261   nstack->next = label_context_stack_vm;
7262   label_context_stack_vm = nstack;
7263 }
7264
7265 /* End a scope which may contain identifiers of variably modified
7266    type, scope number SCOPE.  */
7267
7268 void
7269 c_end_vm_scope (unsigned int scope)
7270 {
7271   if (label_context_stack_vm == NULL)
7272     return;
7273   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7274     c_switch_stack->blocked_vm = 0;
7275   /* We may have a number of nested scopes of identifiers with
7276      variably modified type, all at this depth.  Pop each in turn.  */
7277   while (label_context_stack_vm->scope == scope)
7278     {
7279       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7280
7281       /* It is no longer possible to jump to labels defined within this
7282          scope.  */
7283       for (dlist = label_context_stack_vm->labels_def;
7284            dlist != NULL;
7285            dlist = dlist->next)
7286         {
7287           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7288         }
7289       /* It is again possible to define labels with a goto just outside
7290          this scope.  */
7291       for (glist = label_context_stack_vm->next->labels_used;
7292            glist != NULL;
7293            glist = glist->next)
7294         {
7295           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7296           glist_prev = glist;
7297         }
7298       if (glist_prev != NULL)
7299         glist_prev->next = label_context_stack_vm->labels_used;
7300       else
7301         label_context_stack_vm->next->labels_used
7302           = label_context_stack_vm->labels_used;
7303       label_context_stack_vm = label_context_stack_vm->next;
7304     }
7305 }
7306 \f
7307 /* Begin and end compound statements.  This is as simple as pushing
7308    and popping new statement lists from the tree.  */
7309
7310 tree
7311 c_begin_compound_stmt (bool do_scope)
7312 {
7313   tree stmt = push_stmt_list ();
7314   if (do_scope)
7315     push_scope ();
7316   return stmt;
7317 }
7318
7319 tree
7320 c_end_compound_stmt (tree stmt, bool do_scope)
7321 {
7322   tree block = NULL;
7323
7324   if (do_scope)
7325     {
7326       if (c_dialect_objc ())
7327         objc_clear_super_receiver ();
7328       block = pop_scope ();
7329     }
7330
7331   stmt = pop_stmt_list (stmt);
7332   stmt = c_build_bind_expr (block, stmt);
7333
7334   /* If this compound statement is nested immediately inside a statement
7335      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7336      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7337      STATEMENT_LISTs merge, and thus we can lose track of what statement
7338      was really last.  */
7339   if (cur_stmt_list
7340       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7341       && TREE_CODE (stmt) != BIND_EXPR)
7342     {
7343       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7344       TREE_SIDE_EFFECTS (stmt) = 1;
7345     }
7346
7347   return stmt;
7348 }
7349
7350 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7351    when the current scope is exited.  EH_ONLY is true when this is not
7352    meant to apply to normal control flow transfer.  */
7353
7354 void
7355 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7356 {
7357   enum tree_code code;
7358   tree stmt, list;
7359   bool stmt_expr;
7360
7361   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7362   stmt = build_stmt (code, NULL, cleanup);
7363   add_stmt (stmt);
7364   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7365   list = push_stmt_list ();
7366   TREE_OPERAND (stmt, 0) = list;
7367   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7368 }
7369 \f
7370 /* Build a binary-operation expression without default conversions.
7371    CODE is the kind of expression to build.
7372    This function differs from `build' in several ways:
7373    the data type of the result is computed and recorded in it,
7374    warnings are generated if arg data types are invalid,
7375    special handling for addition and subtraction of pointers is known,
7376    and some optimization is done (operations on narrow ints
7377    are done in the narrower type when that gives the same result).
7378    Constant folding is also done before the result is returned.
7379
7380    Note that the operands will never have enumeral types, or function
7381    or array types, because either they will have the default conversions
7382    performed or they have both just been converted to some other type in which
7383    the arithmetic is to be done.  */
7384
7385 tree
7386 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7387                  int convert_p)
7388 {
7389   tree type0, type1;
7390   enum tree_code code0, code1;
7391   tree op0, op1;
7392
7393   /* Expression code to give to the expression when it is built.
7394      Normally this is CODE, which is what the caller asked for,
7395      but in some special cases we change it.  */
7396   enum tree_code resultcode = code;
7397
7398   /* Data type in which the computation is to be performed.
7399      In the simplest cases this is the common type of the arguments.  */
7400   tree result_type = NULL;
7401
7402   /* Nonzero means operands have already been type-converted
7403      in whatever way is necessary.
7404      Zero means they need to be converted to RESULT_TYPE.  */
7405   int converted = 0;
7406
7407   /* Nonzero means create the expression with this type, rather than
7408      RESULT_TYPE.  */
7409   tree build_type = 0;
7410
7411   /* Nonzero means after finally constructing the expression
7412      convert it to this type.  */
7413   tree final_type = 0;
7414
7415   /* Nonzero if this is an operation like MIN or MAX which can
7416      safely be computed in short if both args are promoted shorts.
7417      Also implies COMMON.
7418      -1 indicates a bitwise operation; this makes a difference
7419      in the exact conditions for when it is safe to do the operation
7420      in a narrower mode.  */
7421   int shorten = 0;
7422
7423   /* Nonzero if this is a comparison operation;
7424      if both args are promoted shorts, compare the original shorts.
7425      Also implies COMMON.  */
7426   int short_compare = 0;
7427
7428   /* Nonzero if this is a right-shift operation, which can be computed on the
7429      original short and then promoted if the operand is a promoted short.  */
7430   int short_shift = 0;
7431
7432   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7433   int common = 0;
7434
7435   /* True means types are compatible as far as ObjC is concerned.  */
7436   bool objc_ok;
7437
7438   if (convert_p)
7439     {
7440       op0 = default_conversion (orig_op0);
7441       op1 = default_conversion (orig_op1);
7442     }
7443   else
7444     {
7445       op0 = orig_op0;
7446       op1 = orig_op1;
7447     }
7448
7449   type0 = TREE_TYPE (op0);
7450   type1 = TREE_TYPE (op1);
7451
7452   /* The expression codes of the data types of the arguments tell us
7453      whether the arguments are integers, floating, pointers, etc.  */
7454   code0 = TREE_CODE (type0);
7455   code1 = TREE_CODE (type1);
7456
7457   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7458   STRIP_TYPE_NOPS (op0);
7459   STRIP_TYPE_NOPS (op1);
7460
7461   /* If an error was already reported for one of the arguments,
7462      avoid reporting another error.  */
7463
7464   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7465     return error_mark_node;
7466
7467   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7468
7469   switch (code)
7470     {
7471     case PLUS_EXPR:
7472       /* Handle the pointer + int case.  */
7473       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7474         return pointer_int_sum (PLUS_EXPR, op0, op1);
7475       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7476         return pointer_int_sum (PLUS_EXPR, op1, op0);
7477       else
7478         common = 1;
7479       break;
7480
7481     case MINUS_EXPR:
7482       /* Subtraction of two similar pointers.
7483          We must subtract them as integers, then divide by object size.  */
7484       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7485           && comp_target_types (type0, type1))
7486         return pointer_diff (op0, op1);
7487       /* Handle pointer minus int.  Just like pointer plus int.  */
7488       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7489         return pointer_int_sum (MINUS_EXPR, op0, op1);
7490       else
7491         common = 1;
7492       break;
7493
7494     case MULT_EXPR:
7495       common = 1;
7496       break;
7497
7498     case TRUNC_DIV_EXPR:
7499     case CEIL_DIV_EXPR:
7500     case FLOOR_DIV_EXPR:
7501     case ROUND_DIV_EXPR:
7502     case EXACT_DIV_EXPR:
7503       /* Floating point division by zero is a legitimate way to obtain
7504          infinities and NaNs.  */
7505       if (skip_evaluation == 0 && integer_zerop (op1))
7506         warning (OPT_Wdiv_by_zero, "division by zero");
7507
7508       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7509            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7510           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7511               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7512         {
7513           enum tree_code tcode0 = code0, tcode1 = code1;
7514
7515           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7516             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7517           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7518             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7519
7520           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7521             resultcode = RDIV_EXPR;
7522           else
7523             /* Although it would be tempting to shorten always here, that
7524                loses on some targets, since the modulo instruction is
7525                undefined if the quotient can't be represented in the
7526                computation mode.  We shorten only if unsigned or if
7527                dividing by something we know != -1.  */
7528             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7529                        || (TREE_CODE (op1) == INTEGER_CST
7530                            && !integer_all_onesp (op1)));
7531           common = 1;
7532         }
7533       break;
7534
7535     case BIT_AND_EXPR:
7536     case BIT_IOR_EXPR:
7537     case BIT_XOR_EXPR:
7538       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7539         shorten = -1;
7540       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7541         common = 1;
7542       break;
7543
7544     case TRUNC_MOD_EXPR:
7545     case FLOOR_MOD_EXPR:
7546       if (skip_evaluation == 0 && integer_zerop (op1))
7547         warning (OPT_Wdiv_by_zero, "division by zero");
7548
7549       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7550         {
7551           /* Although it would be tempting to shorten always here, that loses
7552              on some targets, since the modulo instruction is undefined if the
7553              quotient can't be represented in the computation mode.  We shorten
7554              only if unsigned or if dividing by something we know != -1.  */
7555           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7556                      || (TREE_CODE (op1) == INTEGER_CST
7557                          && !integer_all_onesp (op1)));
7558           common = 1;
7559         }
7560       break;
7561
7562     case TRUTH_ANDIF_EXPR:
7563     case TRUTH_ORIF_EXPR:
7564     case TRUTH_AND_EXPR:
7565     case TRUTH_OR_EXPR:
7566     case TRUTH_XOR_EXPR:
7567       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7568            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7569           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7570               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7571         {
7572           /* Result of these operations is always an int,
7573              but that does not mean the operands should be
7574              converted to ints!  */
7575           result_type = integer_type_node;
7576           op0 = c_common_truthvalue_conversion (op0);
7577           op1 = c_common_truthvalue_conversion (op1);
7578           converted = 1;
7579         }
7580       break;
7581
7582       /* Shift operations: result has same type as first operand;
7583          always convert second operand to int.
7584          Also set SHORT_SHIFT if shifting rightward.  */
7585
7586     case RSHIFT_EXPR:
7587       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7588         {
7589           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7590             {
7591               if (tree_int_cst_sgn (op1) < 0)
7592                 warning (0, "right shift count is negative");
7593               else
7594                 {
7595                   if (!integer_zerop (op1))
7596                     short_shift = 1;
7597
7598                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7599                     warning (0, "right shift count >= width of type");
7600                 }
7601             }
7602
7603           /* Use the type of the value to be shifted.  */
7604           result_type = type0;
7605           /* Convert the shift-count to an integer, regardless of size
7606              of value being shifted.  */
7607           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7608             op1 = convert (integer_type_node, op1);
7609           /* Avoid converting op1 to result_type later.  */
7610           converted = 1;
7611         }
7612       break;
7613
7614     case LSHIFT_EXPR:
7615       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7616         {
7617           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7618             {
7619               if (tree_int_cst_sgn (op1) < 0)
7620                 warning (0, "left shift count is negative");
7621
7622               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7623                 warning (0, "left shift count >= width of type");
7624             }
7625
7626           /* Use the type of the value to be shifted.  */
7627           result_type = type0;
7628           /* Convert the shift-count to an integer, regardless of size
7629              of value being shifted.  */
7630           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7631             op1 = convert (integer_type_node, op1);
7632           /* Avoid converting op1 to result_type later.  */
7633           converted = 1;
7634         }
7635       break;
7636
7637     case EQ_EXPR:
7638     case NE_EXPR:
7639       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7640         warning (OPT_Wfloat_equal,
7641                  "comparing floating point with == or != is unsafe");
7642       /* Result of comparison is always int,
7643          but don't convert the args to int!  */
7644       build_type = integer_type_node;
7645       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7646            || code0 == COMPLEX_TYPE)
7647           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7648               || code1 == COMPLEX_TYPE))
7649         short_compare = 1;
7650       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7651         {
7652           tree tt0 = TREE_TYPE (type0);
7653           tree tt1 = TREE_TYPE (type1);
7654           /* Anything compares with void *.  void * compares with anything.
7655              Otherwise, the targets must be compatible
7656              and both must be object or both incomplete.  */
7657           if (comp_target_types (type0, type1))
7658             result_type = common_pointer_type (type0, type1);
7659           else if (VOID_TYPE_P (tt0))
7660             {
7661               /* op0 != orig_op0 detects the case of something
7662                  whose value is 0 but which isn't a valid null ptr const.  */
7663               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7664                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7665                 pedwarn ("ISO C forbids comparison of %<void *%>"
7666                          " with function pointer");
7667             }
7668           else if (VOID_TYPE_P (tt1))
7669             {
7670               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7671                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7672                 pedwarn ("ISO C forbids comparison of %<void *%>"
7673                          " with function pointer");
7674             }
7675           else
7676             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7677             if (!objc_ok)
7678               pedwarn ("comparison of distinct pointer types lacks a cast");
7679
7680           if (result_type == NULL_TREE)
7681             result_type = ptr_type_node;
7682         }
7683       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7684                && integer_zerop (op1))
7685         result_type = type0;
7686       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7687                && integer_zerop (op0))
7688         result_type = type1;
7689       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7690         {
7691           result_type = type0;
7692           pedwarn ("comparison between pointer and integer");
7693         }
7694       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7695         {
7696           result_type = type1;
7697           pedwarn ("comparison between pointer and integer");
7698         }
7699       break;
7700
7701     case LE_EXPR:
7702     case GE_EXPR:
7703     case LT_EXPR:
7704     case GT_EXPR:
7705       build_type = integer_type_node;
7706       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7707           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7708         short_compare = 1;
7709       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7710         {
7711           if (comp_target_types (type0, type1))
7712             {
7713               result_type = common_pointer_type (type0, type1);
7714               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7715                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7716                 pedwarn ("comparison of complete and incomplete pointers");
7717               else if (pedantic
7718                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7719                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7720             }
7721           else
7722             {
7723               result_type = ptr_type_node;
7724               pedwarn ("comparison of distinct pointer types lacks a cast");
7725             }
7726         }
7727       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7728                && integer_zerop (op1))
7729         {
7730           result_type = type0;
7731           if (pedantic || extra_warnings)
7732             pedwarn ("ordered comparison of pointer with integer zero");
7733         }
7734       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7735                && integer_zerop (op0))
7736         {
7737           result_type = type1;
7738           if (pedantic)
7739             pedwarn ("ordered comparison of pointer with integer zero");
7740         }
7741       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7742         {
7743           result_type = type0;
7744           pedwarn ("comparison between pointer and integer");
7745         }
7746       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7747         {
7748           result_type = type1;
7749           pedwarn ("comparison between pointer and integer");
7750         }
7751       break;
7752
7753     default:
7754       gcc_unreachable ();
7755     }
7756
7757   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7758     return error_mark_node;
7759
7760   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
7761       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
7762           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
7763                                                     TREE_TYPE (type1))))
7764     {
7765       binary_op_error (code);
7766       return error_mark_node;
7767     }
7768
7769   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7770        || code0 == VECTOR_TYPE)
7771       &&
7772       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7773        || code1 == VECTOR_TYPE))
7774     {
7775       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7776
7777       if (shorten || common || short_compare)
7778         result_type = c_common_type (type0, type1);
7779
7780       /* For certain operations (which identify themselves by shorten != 0)
7781          if both args were extended from the same smaller type,
7782          do the arithmetic in that type and then extend.
7783
7784          shorten !=0 and !=1 indicates a bitwise operation.
7785          For them, this optimization is safe only if
7786          both args are zero-extended or both are sign-extended.
7787          Otherwise, we might change the result.
7788          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7789          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7790
7791       if (shorten && none_complex)
7792         {
7793           int unsigned0, unsigned1;
7794           tree arg0 = get_narrower (op0, &unsigned0);
7795           tree arg1 = get_narrower (op1, &unsigned1);
7796           /* UNS is 1 if the operation to be done is an unsigned one.  */
7797           int uns = TYPE_UNSIGNED (result_type);
7798           tree type;
7799
7800           final_type = result_type;
7801
7802           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7803              but it *requires* conversion to FINAL_TYPE.  */
7804
7805           if ((TYPE_PRECISION (TREE_TYPE (op0))
7806                == TYPE_PRECISION (TREE_TYPE (arg0)))
7807               && TREE_TYPE (op0) != final_type)
7808             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7809           if ((TYPE_PRECISION (TREE_TYPE (op1))
7810                == TYPE_PRECISION (TREE_TYPE (arg1)))
7811               && TREE_TYPE (op1) != final_type)
7812             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7813
7814           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7815
7816           /* For bitwise operations, signedness of nominal type
7817              does not matter.  Consider only how operands were extended.  */
7818           if (shorten == -1)
7819             uns = unsigned0;
7820
7821           /* Note that in all three cases below we refrain from optimizing
7822              an unsigned operation on sign-extended args.
7823              That would not be valid.  */
7824
7825           /* Both args variable: if both extended in same way
7826              from same width, do it in that width.
7827              Do it unsigned if args were zero-extended.  */
7828           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7829                < TYPE_PRECISION (result_type))
7830               && (TYPE_PRECISION (TREE_TYPE (arg1))
7831                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7832               && unsigned0 == unsigned1
7833               && (unsigned0 || !uns))
7834             result_type
7835               = c_common_signed_or_unsigned_type
7836               (unsigned0, c_common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7837           else if (TREE_CODE (arg0) == INTEGER_CST
7838                    && (unsigned1 || !uns)
7839                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7840                        < TYPE_PRECISION (result_type))
7841                    && (type
7842                        = c_common_signed_or_unsigned_type (unsigned1,
7843                                                            TREE_TYPE (arg1)),
7844                        int_fits_type_p (arg0, type)))
7845             result_type = type;
7846           else if (TREE_CODE (arg1) == INTEGER_CST
7847                    && (unsigned0 || !uns)
7848                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7849                        < TYPE_PRECISION (result_type))
7850                    && (type
7851                        = c_common_signed_or_unsigned_type (unsigned0,
7852                                                            TREE_TYPE (arg0)),
7853                        int_fits_type_p (arg1, type)))
7854             result_type = type;
7855         }
7856
7857       /* Shifts can be shortened if shifting right.  */
7858
7859       if (short_shift)
7860         {
7861           int unsigned_arg;
7862           tree arg0 = get_narrower (op0, &unsigned_arg);
7863
7864           final_type = result_type;
7865
7866           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7867             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7868
7869           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7870               /* We can shorten only if the shift count is less than the
7871                  number of bits in the smaller type size.  */
7872               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7873               /* We cannot drop an unsigned shift after sign-extension.  */
7874               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7875             {
7876               /* Do an unsigned shift if the operand was zero-extended.  */
7877               result_type
7878                 = c_common_signed_or_unsigned_type (unsigned_arg,
7879                                                     TREE_TYPE (arg0));
7880               /* Convert value-to-be-shifted to that type.  */
7881               if (TREE_TYPE (op0) != result_type)
7882                 op0 = convert (result_type, op0);
7883               converted = 1;
7884             }
7885         }
7886
7887       /* Comparison operations are shortened too but differently.
7888          They identify themselves by setting short_compare = 1.  */
7889
7890       if (short_compare)
7891         {
7892           /* Don't write &op0, etc., because that would prevent op0
7893              from being kept in a register.
7894              Instead, make copies of the our local variables and
7895              pass the copies by reference, then copy them back afterward.  */
7896           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7897           enum tree_code xresultcode = resultcode;
7898           tree val
7899             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7900
7901           if (val != 0)
7902             return val;
7903
7904           op0 = xop0, op1 = xop1;
7905           converted = 1;
7906           resultcode = xresultcode;
7907
7908           if (warn_sign_compare && skip_evaluation == 0)
7909             {
7910               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
7911               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
7912               int unsignedp0, unsignedp1;
7913               tree primop0 = get_narrower (op0, &unsignedp0);
7914               tree primop1 = get_narrower (op1, &unsignedp1);
7915
7916               xop0 = orig_op0;
7917               xop1 = orig_op1;
7918               STRIP_TYPE_NOPS (xop0);
7919               STRIP_TYPE_NOPS (xop1);
7920
7921               /* Give warnings for comparisons between signed and unsigned
7922                  quantities that may fail.
7923
7924                  Do the checking based on the original operand trees, so that
7925                  casts will be considered, but default promotions won't be.
7926
7927                  Do not warn if the comparison is being done in a signed type,
7928                  since the signed type will only be chosen if it can represent
7929                  all the values of the unsigned type.  */
7930               if (!TYPE_UNSIGNED (result_type))
7931                 /* OK */;
7932               /* Do not warn if both operands are the same signedness.  */
7933               else if (op0_signed == op1_signed)
7934                 /* OK */;
7935               else
7936                 {
7937                   tree sop, uop;
7938
7939                   if (op0_signed)
7940                     sop = xop0, uop = xop1;
7941                   else
7942                     sop = xop1, uop = xop0;
7943
7944                   /* Do not warn if the signed quantity is an
7945                      unsuffixed integer literal (or some static
7946                      constant expression involving such literals or a
7947                      conditional expression involving such literals)
7948                      and it is non-negative.  */
7949                   if (tree_expr_nonnegative_p (sop))
7950                     /* OK */;
7951                   /* Do not warn if the comparison is an equality operation,
7952                      the unsigned quantity is an integral constant, and it
7953                      would fit in the result if the result were signed.  */
7954                   else if (TREE_CODE (uop) == INTEGER_CST
7955                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
7956                            && int_fits_type_p
7957                            (uop, c_common_signed_type (result_type)))
7958                     /* OK */;
7959                   /* Do not warn if the unsigned quantity is an enumeration
7960                      constant and its maximum value would fit in the result
7961                      if the result were signed.  */
7962                   else if (TREE_CODE (uop) == INTEGER_CST
7963                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
7964                            && int_fits_type_p
7965                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
7966                             c_common_signed_type (result_type)))
7967                     /* OK */;
7968                   else
7969                     warning (0, "comparison between signed and unsigned");
7970                 }
7971
7972               /* Warn if two unsigned values are being compared in a size
7973                  larger than their original size, and one (and only one) is the
7974                  result of a `~' operator.  This comparison will always fail.
7975
7976                  Also warn if one operand is a constant, and the constant
7977                  does not have all bits set that are set in the ~ operand
7978                  when it is extended.  */
7979
7980               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
7981                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
7982                 {
7983                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
7984                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
7985                                             &unsignedp0);
7986                   else
7987                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
7988                                             &unsignedp1);
7989
7990                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
7991                     {
7992                       tree primop;
7993                       HOST_WIDE_INT constant, mask;
7994                       int unsignedp, bits;
7995
7996                       if (host_integerp (primop0, 0))
7997                         {
7998                           primop = primop1;
7999                           unsignedp = unsignedp1;
8000                           constant = tree_low_cst (primop0, 0);
8001                         }
8002                       else
8003                         {
8004                           primop = primop0;
8005                           unsignedp = unsignedp0;
8006                           constant = tree_low_cst (primop1, 0);
8007                         }
8008
8009                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8010                       if (bits < TYPE_PRECISION (result_type)
8011                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8012                         {
8013                           mask = (~(HOST_WIDE_INT) 0) << bits;
8014                           if ((mask & constant) != mask)
8015                             warning (0, "comparison of promoted ~unsigned with constant");
8016                         }
8017                     }
8018                   else if (unsignedp0 && unsignedp1
8019                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8020                                < TYPE_PRECISION (result_type))
8021                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8022                                < TYPE_PRECISION (result_type)))
8023                     warning (0, "comparison of promoted ~unsigned with unsigned");
8024                 }
8025             }
8026         }
8027     }
8028
8029   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8030      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8031      Then the expression will be built.
8032      It will be given type FINAL_TYPE if that is nonzero;
8033      otherwise, it will be given type RESULT_TYPE.  */
8034
8035   if (!result_type)
8036     {
8037       binary_op_error (code);
8038       return error_mark_node;
8039     }
8040
8041   if (!converted)
8042     {
8043       if (TREE_TYPE (op0) != result_type)
8044         op0 = convert (result_type, op0);
8045       if (TREE_TYPE (op1) != result_type)
8046         op1 = convert (result_type, op1);
8047
8048       /* This can happen if one operand has a vector type, and the other
8049          has a different type.  */
8050       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8051         return error_mark_node;
8052     }
8053
8054   if (build_type == NULL_TREE)
8055     build_type = result_type;
8056
8057   {
8058     tree result = build2 (resultcode, build_type, op0, op1);
8059
8060     /* Treat expressions in initializers specially as they can't trap.  */
8061     result = require_constant_value ? fold_initializer (result)
8062                                     : fold (result);
8063
8064     if (final_type != 0)
8065       result = convert (final_type, result);
8066     return result;
8067   }
8068 }
8069
8070
8071 /* Convert EXPR to be a truth-value, validating its type for this
8072    purpose.  */
8073
8074 tree
8075 c_objc_common_truthvalue_conversion (tree expr)
8076 {
8077   switch (TREE_CODE (TREE_TYPE (expr)))
8078     {
8079     case ARRAY_TYPE:
8080       error ("used array that cannot be converted to pointer where scalar is required");
8081       return error_mark_node;
8082
8083     case RECORD_TYPE:
8084       error ("used struct type value where scalar is required");
8085       return error_mark_node;
8086
8087     case UNION_TYPE:
8088       error ("used union type value where scalar is required");
8089       return error_mark_node;
8090
8091     case FUNCTION_TYPE:
8092       gcc_unreachable ();
8093
8094     default:
8095       break;
8096     }
8097
8098   /* ??? Should we also give an error for void and vectors rather than
8099      leaving those to give errors later?  */
8100   return c_common_truthvalue_conversion (expr);
8101 }