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 (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 /* Convert the array expression EXP to a pointer.  */
1263 static tree
1264 array_to_pointer_conversion (tree exp)
1265 {
1266   tree orig_exp = exp;
1267   tree type = TREE_TYPE (exp);
1268   tree adr;
1269   tree restype = TREE_TYPE (type);
1270   tree ptrtype;
1271
1272   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1273
1274   STRIP_TYPE_NOPS (exp);
1275
1276   if (TREE_NO_WARNING (orig_exp))
1277     TREE_NO_WARNING (exp) = 1;
1278
1279   ptrtype = build_pointer_type (restype);
1280
1281   if (TREE_CODE (exp) == INDIRECT_REF)
1282     return convert (ptrtype, TREE_OPERAND (exp, 0));
1283
1284   if (TREE_CODE (exp) == VAR_DECL)
1285     {
1286       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1287          ADDR_EXPR because it's the best way of representing what
1288          happens in C when we take the address of an array and place
1289          it in a pointer to the element type.  */
1290       adr = build1 (ADDR_EXPR, ptrtype, exp);
1291       if (!c_mark_addressable (exp))
1292         return error_mark_node;
1293       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1294       return adr;
1295     }
1296
1297   /* This way is better for a COMPONENT_REF since it can
1298      simplify the offset for a component.  */
1299   adr = build_unary_op (ADDR_EXPR, exp, 1);
1300   return convert (ptrtype, adr);
1301 }
1302
1303 /* Convert the function expression EXP to a pointer.  */
1304 static tree
1305 function_to_pointer_conversion (tree exp)
1306 {
1307   tree orig_exp = exp;
1308
1309   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1310
1311   STRIP_TYPE_NOPS (exp);
1312
1313   if (TREE_NO_WARNING (orig_exp))
1314     TREE_NO_WARNING (exp) = 1;
1315
1316   return build_unary_op (ADDR_EXPR, exp, 0);
1317 }
1318
1319 /* Perform the default conversion of arrays and functions to pointers.
1320    Return the result of converting EXP.  For any other expression, just
1321    return EXP after removing NOPs.  */
1322
1323 struct c_expr
1324 default_function_array_conversion (struct c_expr exp)
1325 {
1326   tree orig_exp = exp.value;
1327   tree type = TREE_TYPE (exp.value);
1328   enum tree_code code = TREE_CODE (type);
1329
1330   switch (code)
1331     {
1332     case ARRAY_TYPE:
1333       {
1334         bool not_lvalue = false;
1335         bool lvalue_array_p;
1336
1337         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1338                 || TREE_CODE (exp.value) == NOP_EXPR)
1339                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1340           {
1341             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1342               not_lvalue = true;
1343             exp.value = TREE_OPERAND (exp.value, 0);
1344           }
1345
1346         if (TREE_NO_WARNING (orig_exp))
1347           TREE_NO_WARNING (exp.value) = 1;
1348
1349         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1350         if (!flag_isoc99 && !lvalue_array_p)
1351           {
1352             /* Before C99, non-lvalue arrays do not decay to pointers.
1353                Normally, using such an array would be invalid; but it can
1354                be used correctly inside sizeof or as a statement expression.
1355                Thus, do not give an error here; an error will result later.  */
1356             return exp;
1357           }
1358
1359         exp.value = array_to_pointer_conversion (exp.value);
1360       }
1361       break;
1362     case FUNCTION_TYPE:
1363       exp.value = function_to_pointer_conversion (exp.value);
1364       break;
1365     default:
1366       STRIP_TYPE_NOPS (exp.value);
1367       if (TREE_NO_WARNING (orig_exp))
1368         TREE_NO_WARNING (exp.value) = 1;
1369       break;
1370     }
1371
1372   return exp;
1373 }
1374
1375
1376 /* EXP is an expression of integer type.  Apply the integer promotions
1377    to it and return the promoted value.  */
1378
1379 tree
1380 perform_integral_promotions (tree exp)
1381 {
1382   tree type = TREE_TYPE (exp);
1383   enum tree_code code = TREE_CODE (type);
1384
1385   gcc_assert (INTEGRAL_TYPE_P (type));
1386
1387   /* Normally convert enums to int,
1388      but convert wide enums to something wider.  */
1389   if (code == ENUMERAL_TYPE)
1390     {
1391       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1392                                           TYPE_PRECISION (integer_type_node)),
1393                                      ((TYPE_PRECISION (type)
1394                                        >= TYPE_PRECISION (integer_type_node))
1395                                       && TYPE_UNSIGNED (type)));
1396
1397       return convert (type, exp);
1398     }
1399
1400   /* ??? This should no longer be needed now bit-fields have their
1401      proper types.  */
1402   if (TREE_CODE (exp) == COMPONENT_REF
1403       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1404       /* If it's thinner than an int, promote it like a
1405          c_promoting_integer_type_p, otherwise leave it alone.  */
1406       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1407                                TYPE_PRECISION (integer_type_node)))
1408     return convert (integer_type_node, exp);
1409
1410   if (c_promoting_integer_type_p (type))
1411     {
1412       /* Preserve unsignedness if not really getting any wider.  */
1413       if (TYPE_UNSIGNED (type)
1414           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1415         return convert (unsigned_type_node, exp);
1416
1417       return convert (integer_type_node, exp);
1418     }
1419
1420   return exp;
1421 }
1422
1423
1424 /* Perform default promotions for C data used in expressions.
1425    Enumeral types or short or char are converted to int.
1426    In addition, manifest constants symbols are replaced by their values.  */
1427
1428 tree
1429 default_conversion (tree exp)
1430 {
1431   tree orig_exp;
1432   tree type = TREE_TYPE (exp);
1433   enum tree_code code = TREE_CODE (type);
1434
1435   /* Functions and arrays have been converted during parsing.  */
1436   gcc_assert (code != FUNCTION_TYPE);
1437   if (code == ARRAY_TYPE)
1438     return exp;
1439
1440   /* Constants can be used directly unless they're not loadable.  */
1441   if (TREE_CODE (exp) == CONST_DECL)
1442     exp = DECL_INITIAL (exp);
1443
1444   /* Replace a nonvolatile const static variable with its value unless
1445      it is an array, in which case we must be sure that taking the
1446      address of the array produces consistent results.  */
1447   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1448     {
1449       exp = decl_constant_value_for_broken_optimization (exp);
1450       type = TREE_TYPE (exp);
1451     }
1452
1453   /* Strip no-op conversions.  */
1454   orig_exp = exp;
1455   STRIP_TYPE_NOPS (exp);
1456
1457   if (TREE_NO_WARNING (orig_exp))
1458     TREE_NO_WARNING (exp) = 1;
1459
1460   if (INTEGRAL_TYPE_P (type))
1461     return perform_integral_promotions (exp);
1462
1463   if (code == VOID_TYPE)
1464     {
1465       error ("void value not ignored as it ought to be");
1466       return error_mark_node;
1467     }
1468   return exp;
1469 }
1470 \f
1471 /* Look up COMPONENT in a structure or union DECL.
1472
1473    If the component name is not found, returns NULL_TREE.  Otherwise,
1474    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1475    stepping down the chain to the component, which is in the last
1476    TREE_VALUE of the list.  Normally the list is of length one, but if
1477    the component is embedded within (nested) anonymous structures or
1478    unions, the list steps down the chain to the component.  */
1479
1480 static tree
1481 lookup_field (tree decl, tree component)
1482 {
1483   tree type = TREE_TYPE (decl);
1484   tree field;
1485
1486   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1487      to the field elements.  Use a binary search on this array to quickly
1488      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1489      will always be set for structures which have many elements.  */
1490
1491   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1492     {
1493       int bot, top, half;
1494       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1495
1496       field = TYPE_FIELDS (type);
1497       bot = 0;
1498       top = TYPE_LANG_SPECIFIC (type)->s->len;
1499       while (top - bot > 1)
1500         {
1501           half = (top - bot + 1) >> 1;
1502           field = field_array[bot+half];
1503
1504           if (DECL_NAME (field) == NULL_TREE)
1505             {
1506               /* Step through all anon unions in linear fashion.  */
1507               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1508                 {
1509                   field = field_array[bot++];
1510                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1511                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1512                     {
1513                       tree anon = lookup_field (field, component);
1514
1515                       if (anon)
1516                         return tree_cons (NULL_TREE, field, anon);
1517                     }
1518                 }
1519
1520               /* Entire record is only anon unions.  */
1521               if (bot > top)
1522                 return NULL_TREE;
1523
1524               /* Restart the binary search, with new lower bound.  */
1525               continue;
1526             }
1527
1528           if (DECL_NAME (field) == component)
1529             break;
1530           if (DECL_NAME (field) < component)
1531             bot += half;
1532           else
1533             top = bot + half;
1534         }
1535
1536       if (DECL_NAME (field_array[bot]) == component)
1537         field = field_array[bot];
1538       else if (DECL_NAME (field) != component)
1539         return NULL_TREE;
1540     }
1541   else
1542     {
1543       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1544         {
1545           if (DECL_NAME (field) == NULL_TREE
1546               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1547                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1548             {
1549               tree anon = lookup_field (field, component);
1550
1551               if (anon)
1552                 return tree_cons (NULL_TREE, field, anon);
1553             }
1554
1555           if (DECL_NAME (field) == component)
1556             break;
1557         }
1558
1559       if (field == NULL_TREE)
1560         return NULL_TREE;
1561     }
1562
1563   return tree_cons (NULL_TREE, field, NULL_TREE);
1564 }
1565
1566 /* Make an expression to refer to the COMPONENT field of
1567    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1568
1569 tree
1570 build_component_ref (tree datum, tree component)
1571 {
1572   tree type = TREE_TYPE (datum);
1573   enum tree_code code = TREE_CODE (type);
1574   tree field = NULL;
1575   tree ref;
1576
1577   if (!objc_is_public (datum, component))
1578     return error_mark_node;
1579
1580   /* See if there is a field or component with name COMPONENT.  */
1581
1582   if (code == RECORD_TYPE || code == UNION_TYPE)
1583     {
1584       if (!COMPLETE_TYPE_P (type))
1585         {
1586           c_incomplete_type_error (NULL_TREE, type);
1587           return error_mark_node;
1588         }
1589
1590       field = lookup_field (datum, component);
1591
1592       if (!field)
1593         {
1594           error ("%qT has no member named %qE", type, component);
1595           return error_mark_node;
1596         }
1597
1598       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1599          This might be better solved in future the way the C++ front
1600          end does it - by giving the anonymous entities each a
1601          separate name and type, and then have build_component_ref
1602          recursively call itself.  We can't do that here.  */
1603       do
1604         {
1605           tree subdatum = TREE_VALUE (field);
1606
1607           if (TREE_TYPE (subdatum) == error_mark_node)
1608             return error_mark_node;
1609
1610           ref = build3 (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1611                         NULL_TREE);
1612           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1613             TREE_READONLY (ref) = 1;
1614           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1615             TREE_THIS_VOLATILE (ref) = 1;
1616
1617           if (TREE_DEPRECATED (subdatum))
1618             warn_deprecated_use (subdatum);
1619
1620           datum = ref;
1621
1622           field = TREE_CHAIN (field);
1623         }
1624       while (field);
1625
1626       return ref;
1627     }
1628   else if (code != ERROR_MARK)
1629     error ("request for member %qE in something not a structure or union",
1630            component);
1631
1632   return error_mark_node;
1633 }
1634 \f
1635 /* Given an expression PTR for a pointer, return an expression
1636    for the value pointed to.
1637    ERRORSTRING is the name of the operator to appear in error messages.  */
1638
1639 tree
1640 build_indirect_ref (tree ptr, const char *errorstring)
1641 {
1642   tree pointer = default_conversion (ptr);
1643   tree type = TREE_TYPE (pointer);
1644
1645   if (TREE_CODE (type) == POINTER_TYPE)
1646     {
1647       if (TREE_CODE (pointer) == ADDR_EXPR
1648           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1649               == TREE_TYPE (type)))
1650         return TREE_OPERAND (pointer, 0);
1651       else
1652         {
1653           tree t = TREE_TYPE (type);
1654           tree ref;
1655
1656           ref = build1 (INDIRECT_REF, t, pointer);
1657
1658           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1659             {
1660               error ("dereferencing pointer to incomplete type");
1661               return error_mark_node;
1662             }
1663           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1664             warning (0, "dereferencing %<void *%> pointer");
1665
1666           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1667              so that we get the proper error message if the result is used
1668              to assign to.  Also, &* is supposed to be a no-op.
1669              And ANSI C seems to specify that the type of the result
1670              should be the const type.  */
1671           /* A de-reference of a pointer to const is not a const.  It is valid
1672              to change it via some other pointer.  */
1673           TREE_READONLY (ref) = TYPE_READONLY (t);
1674           TREE_SIDE_EFFECTS (ref)
1675             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1676           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1677           return ref;
1678         }
1679     }
1680   else if (TREE_CODE (pointer) != ERROR_MARK)
1681     error ("invalid type argument of %qs", errorstring);
1682   return error_mark_node;
1683 }
1684
1685 /* This handles expressions of the form "a[i]", which denotes
1686    an array reference.
1687
1688    This is logically equivalent in C to *(a+i), but we may do it differently.
1689    If A is a variable or a member, we generate a primitive ARRAY_REF.
1690    This avoids forcing the array out of registers, and can work on
1691    arrays that are not lvalues (for example, members of structures returned
1692    by functions).  */
1693
1694 tree
1695 build_array_ref (tree array, tree index)
1696 {
1697   bool swapped = false;
1698   if (TREE_TYPE (array) == error_mark_node
1699       || TREE_TYPE (index) == error_mark_node)
1700     return error_mark_node;
1701
1702   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1703       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1704     {
1705       tree temp;
1706       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1707           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1708         {
1709           error ("subscripted value is neither array nor pointer");
1710           return error_mark_node;
1711         }
1712       temp = array;
1713       array = index;
1714       index = temp;
1715       swapped = true;
1716     }
1717
1718   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1719     {
1720       error ("array subscript is not an integer");
1721       return error_mark_node;
1722     }
1723
1724   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1725     {
1726       error ("subscripted value is pointer to function");
1727       return error_mark_node;
1728     }
1729
1730   /* Subscripting with type char is likely to lose on a machine where
1731      chars are signed.  So warn on any machine, but optionally.  Don't
1732      warn for unsigned char since that type is safe.  Don't warn for
1733      signed char because anyone who uses that must have done so
1734      deliberately.  ??? Existing practice has also been to warn only
1735      when the char index is syntactically the index, not for
1736      char[array].  */
1737   if (!swapped
1738       && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1739     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
1740
1741   /* Apply default promotions *after* noticing character types.  */
1742   index = default_conversion (index);
1743
1744   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1745
1746   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1747     {
1748       tree rval, type;
1749
1750       /* An array that is indexed by a non-constant
1751          cannot be stored in a register; we must be able to do
1752          address arithmetic on its address.
1753          Likewise an array of elements of variable size.  */
1754       if (TREE_CODE (index) != INTEGER_CST
1755           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1756               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1757         {
1758           if (!c_mark_addressable (array))
1759             return error_mark_node;
1760         }
1761       /* An array that is indexed by a constant value which is not within
1762          the array bounds cannot be stored in a register either; because we
1763          would get a crash in store_bit_field/extract_bit_field when trying
1764          to access a non-existent part of the register.  */
1765       if (TREE_CODE (index) == INTEGER_CST
1766           && TYPE_DOMAIN (TREE_TYPE (array))
1767           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1768         {
1769           if (!c_mark_addressable (array))
1770             return error_mark_node;
1771         }
1772
1773       if (pedantic)
1774         {
1775           tree foo = array;
1776           while (TREE_CODE (foo) == COMPONENT_REF)
1777             foo = TREE_OPERAND (foo, 0);
1778           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1779             pedwarn ("ISO C forbids subscripting %<register%> array");
1780           else if (!flag_isoc99 && !lvalue_p (foo))
1781             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1782         }
1783
1784       type = TREE_TYPE (TREE_TYPE (array));
1785       if (TREE_CODE (type) != ARRAY_TYPE)
1786         type = TYPE_MAIN_VARIANT (type);
1787       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1788       /* Array ref is const/volatile if the array elements are
1789          or if the array is.  */
1790       TREE_READONLY (rval)
1791         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1792             | TREE_READONLY (array));
1793       TREE_SIDE_EFFECTS (rval)
1794         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1795             | TREE_SIDE_EFFECTS (array));
1796       TREE_THIS_VOLATILE (rval)
1797         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1798             /* This was added by rms on 16 Nov 91.
1799                It fixes  vol struct foo *a;  a->elts[1]
1800                in an inline function.
1801                Hope it doesn't break something else.  */
1802             | TREE_THIS_VOLATILE (array));
1803       return require_complete_type (fold (rval));
1804     }
1805   else
1806     {
1807       tree ar = default_conversion (array);
1808
1809       if (ar == error_mark_node)
1810         return ar;
1811
1812       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1813       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1814
1815       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1816                                  "array indexing");
1817     }
1818 }
1819 \f
1820 /* Build an external reference to identifier ID.  FUN indicates
1821    whether this will be used for a function call.  LOC is the source
1822    location of the identifier.  */
1823 tree
1824 build_external_ref (tree id, int fun, location_t loc)
1825 {
1826   tree ref;
1827   tree decl = lookup_name (id);
1828
1829   /* In Objective-C, an instance variable (ivar) may be preferred to
1830      whatever lookup_name() found.  */
1831   decl = objc_lookup_ivar (decl, id);
1832
1833   if (decl && decl != error_mark_node)
1834     ref = decl;
1835   else if (fun)
1836     /* Implicit function declaration.  */
1837     ref = implicitly_declare (id);
1838   else if (decl == error_mark_node)
1839     /* Don't complain about something that's already been
1840        complained about.  */
1841     return error_mark_node;
1842   else
1843     {
1844       undeclared_variable (id, loc);
1845       return error_mark_node;
1846     }
1847
1848   if (TREE_TYPE (ref) == error_mark_node)
1849     return error_mark_node;
1850
1851   if (TREE_DEPRECATED (ref))
1852     warn_deprecated_use (ref);
1853
1854   if (!skip_evaluation)
1855     assemble_external (ref);
1856   TREE_USED (ref) = 1;
1857
1858   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
1859     {
1860       if (!in_sizeof && !in_typeof)
1861         C_DECL_USED (ref) = 1;
1862       else if (DECL_INITIAL (ref) == 0
1863                && DECL_EXTERNAL (ref)
1864                && !TREE_PUBLIC (ref))
1865         record_maybe_used_decl (ref);
1866     }
1867
1868   if (TREE_CODE (ref) == CONST_DECL)
1869     {
1870       ref = DECL_INITIAL (ref);
1871       TREE_CONSTANT (ref) = 1;
1872       TREE_INVARIANT (ref) = 1;
1873     }
1874   else if (current_function_decl != 0
1875            && !DECL_FILE_SCOPE_P (current_function_decl)
1876            && (TREE_CODE (ref) == VAR_DECL
1877                || TREE_CODE (ref) == PARM_DECL
1878                || TREE_CODE (ref) == FUNCTION_DECL))
1879     {
1880       tree context = decl_function_context (ref);
1881
1882       if (context != 0 && context != current_function_decl)
1883         DECL_NONLOCAL (ref) = 1;
1884     }
1885
1886   return ref;
1887 }
1888
1889 /* Record details of decls possibly used inside sizeof or typeof.  */
1890 struct maybe_used_decl
1891 {
1892   /* The decl.  */
1893   tree decl;
1894   /* The level seen at (in_sizeof + in_typeof).  */
1895   int level;
1896   /* The next one at this level or above, or NULL.  */
1897   struct maybe_used_decl *next;
1898 };
1899
1900 static struct maybe_used_decl *maybe_used_decls;
1901
1902 /* Record that DECL, an undefined static function reference seen
1903    inside sizeof or typeof, might be used if the operand of sizeof is
1904    a VLA type or the operand of typeof is a variably modified
1905    type.  */
1906
1907 static void
1908 record_maybe_used_decl (tree decl)
1909 {
1910   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
1911   t->decl = decl;
1912   t->level = in_sizeof + in_typeof;
1913   t->next = maybe_used_decls;
1914   maybe_used_decls = t;
1915 }
1916
1917 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
1918    USED is false, just discard them.  If it is true, mark them used
1919    (if no longer inside sizeof or typeof) or move them to the next
1920    level up (if still inside sizeof or typeof).  */
1921
1922 void
1923 pop_maybe_used (bool used)
1924 {
1925   struct maybe_used_decl *p = maybe_used_decls;
1926   int cur_level = in_sizeof + in_typeof;
1927   while (p && p->level > cur_level)
1928     {
1929       if (used)
1930         {
1931           if (cur_level == 0)
1932             C_DECL_USED (p->decl) = 1;
1933           else
1934             p->level = cur_level;
1935         }
1936       p = p->next;
1937     }
1938   if (!used || cur_level == 0)
1939     maybe_used_decls = p;
1940 }
1941
1942 /* Return the result of sizeof applied to EXPR.  */
1943
1944 struct c_expr
1945 c_expr_sizeof_expr (struct c_expr expr)
1946 {
1947   struct c_expr ret;
1948   if (expr.value == error_mark_node)
1949     {
1950       ret.value = error_mark_node;
1951       ret.original_code = ERROR_MARK;
1952       pop_maybe_used (false);
1953     }
1954   else
1955     {
1956       ret.value = c_sizeof (TREE_TYPE (expr.value));
1957       ret.original_code = ERROR_MARK;
1958       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
1959     }
1960   return ret;
1961 }
1962
1963 /* Return the result of sizeof applied to T, a structure for the type
1964    name passed to sizeof (rather than the type itself).  */
1965
1966 struct c_expr
1967 c_expr_sizeof_type (struct c_type_name *t)
1968 {
1969   tree type;
1970   struct c_expr ret;
1971   type = groktypename (t);
1972   ret.value = c_sizeof (type);
1973   ret.original_code = ERROR_MARK;
1974   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
1975   return ret;
1976 }
1977
1978 /* Build a function call to function FUNCTION with parameters PARAMS.
1979    PARAMS is a list--a chain of TREE_LIST nodes--in which the
1980    TREE_VALUE of each node is a parameter-expression.
1981    FUNCTION's data type may be a function type or a pointer-to-function.  */
1982
1983 tree
1984 build_function_call (tree function, tree params)
1985 {
1986   tree fntype, fundecl = 0;
1987   tree coerced_params;
1988   tree name = NULL_TREE, result;
1989   tree tem;
1990
1991   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
1992   STRIP_TYPE_NOPS (function);
1993
1994   /* Convert anything with function type to a pointer-to-function.  */
1995   if (TREE_CODE (function) == FUNCTION_DECL)
1996     {
1997       /* Implement type-directed function overloading for builtins.
1998          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
1999          handle all the type checking.  The result is a complete expression
2000          that implements this function call.  */
2001       tem = resolve_overloaded_builtin (function, params);
2002       if (tem)
2003         return tem;
2004
2005       name = DECL_NAME (function);
2006       fundecl = function;
2007     }
2008   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2009     function = function_to_pointer_conversion (function);
2010
2011   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2012      expressions, like those used for ObjC messenger dispatches.  */
2013   function = objc_rewrite_function_call (function, params);
2014
2015   fntype = TREE_TYPE (function);
2016
2017   if (TREE_CODE (fntype) == ERROR_MARK)
2018     return error_mark_node;
2019
2020   if (!(TREE_CODE (fntype) == POINTER_TYPE
2021         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2022     {
2023       error ("called object %qE is not a function", function);
2024       return error_mark_node;
2025     }
2026
2027   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2028     current_function_returns_abnormally = 1;
2029
2030   /* fntype now gets the type of function pointed to.  */
2031   fntype = TREE_TYPE (fntype);
2032
2033   /* Check that the function is called through a compatible prototype.
2034      If it is not, replace the call by a trap, wrapped up in a compound
2035      expression if necessary.  This has the nice side-effect to prevent
2036      the tree-inliner from generating invalid assignment trees which may
2037      blow up in the RTL expander later.  */
2038   if (TREE_CODE (function) == NOP_EXPR
2039       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2040       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2041       && !comptypes (fntype, TREE_TYPE (tem)))
2042     {
2043       tree return_type = TREE_TYPE (fntype);
2044       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2045                                        NULL_TREE);
2046
2047       /* This situation leads to run-time undefined behavior.  We can't,
2048          therefore, simply error unless we can prove that all possible
2049          executions of the program must execute the code.  */
2050       warning (0, "function called through a non-compatible type");
2051
2052       /* We can, however, treat "undefined" any way we please.
2053          Call abort to encourage the user to fix the program.  */
2054       inform ("if this code is reached, the program will abort");
2055
2056       if (VOID_TYPE_P (return_type))
2057         return trap;
2058       else
2059         {
2060           tree rhs;
2061
2062           if (AGGREGATE_TYPE_P (return_type))
2063             rhs = build_compound_literal (return_type,
2064                                           build_constructor (return_type,
2065                                                              NULL_TREE));
2066           else
2067             rhs = fold_build1 (NOP_EXPR, return_type, integer_zero_node);
2068
2069           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2070         }
2071     }
2072
2073   /* Convert the parameters to the types declared in the
2074      function prototype, or apply default promotions.  */
2075
2076   coerced_params
2077     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2078
2079   if (coerced_params == error_mark_node)
2080     return error_mark_node;
2081
2082   /* Check that the arguments to the function are valid.  */
2083
2084   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2085                             TYPE_ARG_TYPES (fntype));
2086
2087   result = build3 (CALL_EXPR, TREE_TYPE (fntype),
2088                    function, coerced_params, NULL_TREE);
2089   TREE_SIDE_EFFECTS (result) = 1;
2090
2091   if (require_constant_value)
2092     {
2093       result = fold_initializer (result);
2094
2095       if (TREE_CONSTANT (result)
2096           && (name == NULL_TREE
2097               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2098         pedwarn_init ("initializer element is not constant");
2099     }
2100   else
2101     result = fold (result);
2102
2103   if (VOID_TYPE_P (TREE_TYPE (result)))
2104     return result;
2105   return require_complete_type (result);
2106 }
2107 \f
2108 /* Convert the argument expressions in the list VALUES
2109    to the types in the list TYPELIST.  The result is a list of converted
2110    argument expressions, unless there are too few arguments in which
2111    case it is error_mark_node.
2112
2113    If TYPELIST is exhausted, or when an element has NULL as its type,
2114    perform the default conversions.
2115
2116    PARMLIST is the chain of parm decls for the function being called.
2117    It may be 0, if that info is not available.
2118    It is used only for generating error messages.
2119
2120    FUNCTION is a tree for the called function.  It is used only for
2121    error messages, where it is formatted with %qE.
2122
2123    This is also where warnings about wrong number of args are generated.
2124
2125    Both VALUES and the returned value are chains of TREE_LIST nodes
2126    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2127
2128 static tree
2129 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2130 {
2131   tree typetail, valtail;
2132   tree result = NULL;
2133   int parmnum;
2134   tree selector;
2135
2136   /* Change pointer to function to the function itself for
2137      diagnostics.  */
2138   if (TREE_CODE (function) == ADDR_EXPR
2139       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2140     function = TREE_OPERAND (function, 0);
2141
2142   /* Handle an ObjC selector specially for diagnostics.  */
2143   selector = objc_message_selector ();
2144
2145   /* Scan the given expressions and types, producing individual
2146      converted arguments and pushing them on RESULT in reverse order.  */
2147
2148   for (valtail = values, typetail = typelist, parmnum = 0;
2149        valtail;
2150        valtail = TREE_CHAIN (valtail), parmnum++)
2151     {
2152       tree type = typetail ? TREE_VALUE (typetail) : 0;
2153       tree val = TREE_VALUE (valtail);
2154       tree rname = function;
2155       int argnum = parmnum + 1;
2156       const char *invalid_func_diag;
2157
2158       if (type == void_type_node)
2159         {
2160           error ("too many arguments to function %qE", function);
2161           break;
2162         }
2163
2164       if (selector && argnum > 2)
2165         {
2166           rname = selector;
2167           argnum -= 2;
2168         }
2169
2170       STRIP_TYPE_NOPS (val);
2171
2172       val = require_complete_type (val);
2173
2174       if (type != 0)
2175         {
2176           /* Formal parm type is specified by a function prototype.  */
2177           tree parmval;
2178
2179           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2180             {
2181               error ("type of formal parameter %d is incomplete", parmnum + 1);
2182               parmval = val;
2183             }
2184           else
2185             {
2186               /* Optionally warn about conversions that
2187                  differ from the default conversions.  */
2188               if (warn_conversion || warn_traditional)
2189                 {
2190                   unsigned int formal_prec = TYPE_PRECISION (type);
2191
2192                   if (INTEGRAL_TYPE_P (type)
2193                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2194                     warning (0, "passing argument %d of %qE as integer "
2195                              "rather than floating due to prototype",
2196                              argnum, rname);
2197                   if (INTEGRAL_TYPE_P (type)
2198                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2199                     warning (0, "passing argument %d of %qE as integer "
2200                              "rather than complex due to prototype",
2201                              argnum, rname);
2202                   else if (TREE_CODE (type) == COMPLEX_TYPE
2203                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2204                     warning (0, "passing argument %d of %qE as complex "
2205                              "rather than floating due to prototype",
2206                              argnum, rname);
2207                   else if (TREE_CODE (type) == REAL_TYPE
2208                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2209                     warning (0, "passing argument %d of %qE as floating "
2210                              "rather than integer due to prototype",
2211                              argnum, rname);
2212                   else if (TREE_CODE (type) == COMPLEX_TYPE
2213                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2214                     warning (0, "passing argument %d of %qE as complex "
2215                              "rather than integer due to prototype",
2216                              argnum, rname);
2217                   else if (TREE_CODE (type) == REAL_TYPE
2218                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2219                     warning (0, "passing argument %d of %qE as floating "
2220                              "rather than complex due to prototype",
2221                              argnum, rname);
2222                   /* ??? At some point, messages should be written about
2223                      conversions between complex types, but that's too messy
2224                      to do now.  */
2225                   else if (TREE_CODE (type) == REAL_TYPE
2226                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2227                     {
2228                       /* Warn if any argument is passed as `float',
2229                          since without a prototype it would be `double'.  */
2230                       if (formal_prec == TYPE_PRECISION (float_type_node))
2231                         warning (0, "passing argument %d of %qE as %<float%> "
2232                                  "rather than %<double%> due to prototype",
2233                                  argnum, rname);
2234                     }
2235                   /* Detect integer changing in width or signedness.
2236                      These warnings are only activated with
2237                      -Wconversion, not with -Wtraditional.  */
2238                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2239                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2240                     {
2241                       tree would_have_been = default_conversion (val);
2242                       tree type1 = TREE_TYPE (would_have_been);
2243
2244                       if (TREE_CODE (type) == ENUMERAL_TYPE
2245                           && (TYPE_MAIN_VARIANT (type)
2246                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2247                         /* No warning if function asks for enum
2248                            and the actual arg is that enum type.  */
2249                         ;
2250                       else if (formal_prec != TYPE_PRECISION (type1))
2251                         warning (OPT_Wconversion, "passing argument %d of %qE "
2252                                  "with different width due to prototype",
2253                                  argnum, rname);
2254                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2255                         ;
2256                       /* Don't complain if the formal parameter type
2257                          is an enum, because we can't tell now whether
2258                          the value was an enum--even the same enum.  */
2259                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2260                         ;
2261                       else if (TREE_CODE (val) == INTEGER_CST
2262                                && int_fits_type_p (val, type))
2263                         /* Change in signedness doesn't matter
2264                            if a constant value is unaffected.  */
2265                         ;
2266                       /* If the value is extended from a narrower
2267                          unsigned type, it doesn't matter whether we
2268                          pass it as signed or unsigned; the value
2269                          certainly is the same either way.  */
2270                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2271                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2272                         ;
2273                       else if (TYPE_UNSIGNED (type))
2274                         warning (OPT_Wconversion, "passing argument %d of %qE "
2275                                  "as unsigned due to prototype",
2276                                  argnum, rname);
2277                       else
2278                         warning (OPT_Wconversion, "passing argument %d of %qE "
2279                                  "as signed due to prototype", argnum, rname);
2280                     }
2281                 }
2282
2283               parmval = convert_for_assignment (type, val, ic_argpass,
2284                                                 fundecl, function,
2285                                                 parmnum + 1);
2286
2287               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2288                   && INTEGRAL_TYPE_P (type)
2289                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2290                 parmval = default_conversion (parmval);
2291             }
2292           result = tree_cons (NULL_TREE, parmval, result);
2293         }
2294       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2295                && (TYPE_PRECISION (TREE_TYPE (val))
2296                    < TYPE_PRECISION (double_type_node)))
2297         /* Convert `float' to `double'.  */
2298         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2299       else if ((invalid_func_diag =
2300                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2301         {
2302           error (invalid_func_diag);
2303           return error_mark_node;
2304         }
2305       else
2306         /* Convert `short' and `char' to full-size `int'.  */
2307         result = tree_cons (NULL_TREE, default_conversion (val), result);
2308
2309       if (typetail)
2310         typetail = TREE_CHAIN (typetail);
2311     }
2312
2313   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2314     {
2315       error ("too few arguments to function %qE", function);
2316       return error_mark_node;
2317     }
2318
2319   return nreverse (result);
2320 }
2321 \f
2322 /* This is the entry point used by the parser to build unary operators
2323    in the input.  CODE, a tree_code, specifies the unary operator, and
2324    ARG is the operand.  For unary plus, the C parser currently uses
2325    CONVERT_EXPR for code.  */
2326
2327 struct c_expr
2328 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2329 {
2330   struct c_expr result;
2331
2332   result.original_code = ERROR_MARK;
2333   result.value = build_unary_op (code, arg.value, 0);
2334   overflow_warning (result.value);
2335   return result;
2336 }
2337
2338 /* This is the entry point used by the parser to build binary operators
2339    in the input.  CODE, a tree_code, specifies the binary operator, and
2340    ARG1 and ARG2 are the operands.  In addition to constructing the
2341    expression, we check for operands that were written with other binary
2342    operators in a way that is likely to confuse the user.  */
2343
2344 struct c_expr
2345 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2346                         struct c_expr arg2)
2347 {
2348   struct c_expr result;
2349
2350   enum tree_code code1 = arg1.original_code;
2351   enum tree_code code2 = arg2.original_code;
2352
2353   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2354   result.original_code = code;
2355
2356   if (TREE_CODE (result.value) == ERROR_MARK)
2357     return result;
2358
2359   /* Check for cases such as x+y<<z which users are likely
2360      to misinterpret.  */
2361   if (warn_parentheses)
2362     {
2363       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2364         {
2365           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2366               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2367             warning (0, "suggest parentheses around + or - inside shift");
2368         }
2369
2370       if (code == TRUTH_ORIF_EXPR)
2371         {
2372           if (code1 == TRUTH_ANDIF_EXPR
2373               || code2 == TRUTH_ANDIF_EXPR)
2374             warning (0, "suggest parentheses around && within ||");
2375         }
2376
2377       if (code == BIT_IOR_EXPR)
2378         {
2379           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2380               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2381               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2382               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2383             warning (0, "suggest parentheses around arithmetic in operand of |");
2384           /* Check cases like x|y==z */
2385           if (TREE_CODE_CLASS (code1) == tcc_comparison
2386               || TREE_CODE_CLASS (code2) == tcc_comparison)
2387             warning (0, "suggest parentheses around comparison in operand of |");
2388         }
2389
2390       if (code == BIT_XOR_EXPR)
2391         {
2392           if (code1 == BIT_AND_EXPR
2393               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2394               || code2 == BIT_AND_EXPR
2395               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2396             warning (0, "suggest parentheses around arithmetic in operand of ^");
2397           /* Check cases like x^y==z */
2398           if (TREE_CODE_CLASS (code1) == tcc_comparison
2399               || TREE_CODE_CLASS (code2) == tcc_comparison)
2400             warning (0, "suggest parentheses around comparison in operand of ^");
2401         }
2402
2403       if (code == BIT_AND_EXPR)
2404         {
2405           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2406               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2407             warning (0, "suggest parentheses around + or - in operand of &");
2408           /* Check cases like x&y==z */
2409           if (TREE_CODE_CLASS (code1) == tcc_comparison
2410               || TREE_CODE_CLASS (code2) == tcc_comparison)
2411             warning (0, "suggest parentheses around comparison in operand of &");
2412         }
2413       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2414       if (TREE_CODE_CLASS (code) == tcc_comparison
2415           && (TREE_CODE_CLASS (code1) == tcc_comparison
2416               || TREE_CODE_CLASS (code2) == tcc_comparison))
2417         warning (0, "comparisons like X<=Y<=Z do not have their mathematical meaning");
2418
2419     }
2420
2421   unsigned_conversion_warning (result.value, arg1.value);
2422   unsigned_conversion_warning (result.value, arg2.value);
2423   overflow_warning (result.value);
2424
2425   return result;
2426 }
2427 \f
2428 /* Return a tree for the difference of pointers OP0 and OP1.
2429    The resulting tree has type int.  */
2430
2431 static tree
2432 pointer_diff (tree op0, tree op1)
2433 {
2434   tree restype = ptrdiff_type_node;
2435
2436   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2437   tree con0, con1, lit0, lit1;
2438   tree orig_op1 = op1;
2439
2440   if (pedantic || warn_pointer_arith)
2441     {
2442       if (TREE_CODE (target_type) == VOID_TYPE)
2443         pedwarn ("pointer of type %<void *%> used in subtraction");
2444       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2445         pedwarn ("pointer to a function used in subtraction");
2446     }
2447
2448   /* If the conversion to ptrdiff_type does anything like widening or
2449      converting a partial to an integral mode, we get a convert_expression
2450      that is in the way to do any simplifications.
2451      (fold-const.c doesn't know that the extra bits won't be needed.
2452      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2453      different mode in place.)
2454      So first try to find a common term here 'by hand'; we want to cover
2455      at least the cases that occur in legal static initializers.  */
2456   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2457   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2458
2459   if (TREE_CODE (con0) == PLUS_EXPR)
2460     {
2461       lit0 = TREE_OPERAND (con0, 1);
2462       con0 = TREE_OPERAND (con0, 0);
2463     }
2464   else
2465     lit0 = integer_zero_node;
2466
2467   if (TREE_CODE (con1) == PLUS_EXPR)
2468     {
2469       lit1 = TREE_OPERAND (con1, 1);
2470       con1 = TREE_OPERAND (con1, 0);
2471     }
2472   else
2473     lit1 = integer_zero_node;
2474
2475   if (operand_equal_p (con0, con1, 0))
2476     {
2477       op0 = lit0;
2478       op1 = lit1;
2479     }
2480
2481
2482   /* First do the subtraction as integers;
2483      then drop through to build the divide operator.
2484      Do not do default conversions on the minus operator
2485      in case restype is a short type.  */
2486
2487   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2488                          convert (restype, op1), 0);
2489   /* This generates an error if op1 is pointer to incomplete type.  */
2490   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2491     error ("arithmetic on pointer to an incomplete type");
2492
2493   /* This generates an error if op0 is pointer to incomplete type.  */
2494   op1 = c_size_in_bytes (target_type);
2495
2496   /* Divide by the size, in easiest possible way.  */
2497   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2498 }
2499 \f
2500 /* Construct and perhaps optimize a tree representation
2501    for a unary operation.  CODE, a tree_code, specifies the operation
2502    and XARG is the operand.
2503    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2504    the default promotions (such as from short to int).
2505    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2506    allows non-lvalues; this is only used to handle conversion of non-lvalue
2507    arrays to pointers in C99.  */
2508
2509 tree
2510 build_unary_op (enum tree_code code, tree xarg, int flag)
2511 {
2512   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2513   tree arg = xarg;
2514   tree argtype = 0;
2515   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2516   tree val;
2517   int noconvert = flag;
2518   const char *invalid_op_diag;
2519
2520   if (typecode == ERROR_MARK)
2521     return error_mark_node;
2522   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2523     typecode = INTEGER_TYPE;
2524
2525   if ((invalid_op_diag
2526        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2527     {
2528       error (invalid_op_diag);
2529       return error_mark_node;
2530     }
2531
2532   switch (code)
2533     {
2534     case CONVERT_EXPR:
2535       /* This is used for unary plus, because a CONVERT_EXPR
2536          is enough to prevent anybody from looking inside for
2537          associativity, but won't generate any code.  */
2538       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2539             || typecode == COMPLEX_TYPE
2540             || typecode == VECTOR_TYPE))
2541         {
2542           error ("wrong type argument to unary plus");
2543           return error_mark_node;
2544         }
2545       else if (!noconvert)
2546         arg = default_conversion (arg);
2547       arg = non_lvalue (arg);
2548       break;
2549
2550     case NEGATE_EXPR:
2551       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2552             || typecode == COMPLEX_TYPE
2553             || typecode == VECTOR_TYPE))
2554         {
2555           error ("wrong type argument to unary minus");
2556           return error_mark_node;
2557         }
2558       else if (!noconvert)
2559         arg = default_conversion (arg);
2560       break;
2561
2562     case BIT_NOT_EXPR:
2563       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2564         {
2565           if (!noconvert)
2566             arg = default_conversion (arg);
2567         }
2568       else if (typecode == COMPLEX_TYPE)
2569         {
2570           code = CONJ_EXPR;
2571           if (pedantic)
2572             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2573           if (!noconvert)
2574             arg = default_conversion (arg);
2575         }
2576       else
2577         {
2578           error ("wrong type argument to bit-complement");
2579           return error_mark_node;
2580         }
2581       break;
2582
2583     case ABS_EXPR:
2584       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2585         {
2586           error ("wrong type argument to abs");
2587           return error_mark_node;
2588         }
2589       else if (!noconvert)
2590         arg = default_conversion (arg);
2591       break;
2592
2593     case CONJ_EXPR:
2594       /* Conjugating a real value is a no-op, but allow it anyway.  */
2595       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2596             || typecode == COMPLEX_TYPE))
2597         {
2598           error ("wrong type argument to conjugation");
2599           return error_mark_node;
2600         }
2601       else if (!noconvert)
2602         arg = default_conversion (arg);
2603       break;
2604
2605     case TRUTH_NOT_EXPR:
2606       if (typecode != INTEGER_TYPE
2607           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2608           && typecode != COMPLEX_TYPE)
2609         {
2610           error ("wrong type argument to unary exclamation mark");
2611           return error_mark_node;
2612         }
2613       arg = c_objc_common_truthvalue_conversion (arg);
2614       return invert_truthvalue (arg);
2615
2616     case NOP_EXPR:
2617       break;
2618
2619     case REALPART_EXPR:
2620       if (TREE_CODE (arg) == COMPLEX_CST)
2621         return TREE_REALPART (arg);
2622       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2623         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2624       else
2625         return arg;
2626
2627     case IMAGPART_EXPR:
2628       if (TREE_CODE (arg) == COMPLEX_CST)
2629         return TREE_IMAGPART (arg);
2630       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2631         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2632       else
2633         return convert (TREE_TYPE (arg), integer_zero_node);
2634
2635     case PREINCREMENT_EXPR:
2636     case POSTINCREMENT_EXPR:
2637     case PREDECREMENT_EXPR:
2638     case POSTDECREMENT_EXPR:
2639
2640       /* Increment or decrement the real part of the value,
2641          and don't change the imaginary part.  */
2642       if (typecode == COMPLEX_TYPE)
2643         {
2644           tree real, imag;
2645
2646           if (pedantic)
2647             pedwarn ("ISO C does not support %<++%> and %<--%>"
2648                      " on complex types");
2649
2650           arg = stabilize_reference (arg);
2651           real = build_unary_op (REALPART_EXPR, arg, 1);
2652           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2653           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2654                          build_unary_op (code, real, 1), imag);
2655         }
2656
2657       /* Report invalid types.  */
2658
2659       if (typecode != POINTER_TYPE
2660           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2661         {
2662           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2663             error ("wrong type argument to increment");
2664           else
2665             error ("wrong type argument to decrement");
2666
2667           return error_mark_node;
2668         }
2669
2670       {
2671         tree inc;
2672         tree result_type = TREE_TYPE (arg);
2673
2674         arg = get_unwidened (arg, 0);
2675         argtype = TREE_TYPE (arg);
2676
2677         /* Compute the increment.  */
2678
2679         if (typecode == POINTER_TYPE)
2680           {
2681             /* If pointer target is an undefined struct,
2682                we just cannot know how to do the arithmetic.  */
2683             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2684               {
2685                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2686                   error ("increment of pointer to unknown structure");
2687                 else
2688                   error ("decrement of pointer to unknown structure");
2689               }
2690             else if ((pedantic || warn_pointer_arith)
2691                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2692                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2693               {
2694                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2695                   pedwarn ("wrong type argument to increment");
2696                 else
2697                   pedwarn ("wrong type argument to decrement");
2698               }
2699
2700             inc = c_size_in_bytes (TREE_TYPE (result_type));
2701           }
2702         else
2703           inc = integer_one_node;
2704
2705         inc = convert (argtype, inc);
2706
2707         /* Complain about anything else that is not a true lvalue.  */
2708         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2709                                     || code == POSTINCREMENT_EXPR)
2710                                    ? lv_increment
2711                                    : lv_decrement)))
2712           return error_mark_node;
2713
2714         /* Report a read-only lvalue.  */
2715         if (TREE_READONLY (arg))
2716           readonly_error (arg,
2717                           ((code == PREINCREMENT_EXPR
2718                             || code == POSTINCREMENT_EXPR)
2719                            ? lv_increment : lv_decrement));
2720
2721         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2722           val = boolean_increment (code, arg);
2723         else
2724           val = build2 (code, TREE_TYPE (arg), arg, inc);
2725         TREE_SIDE_EFFECTS (val) = 1;
2726         val = convert (result_type, val);
2727         if (TREE_CODE (val) != code)
2728           TREE_NO_WARNING (val) = 1;
2729         return val;
2730       }
2731
2732     case ADDR_EXPR:
2733       /* Note that this operation never does default_conversion.  */
2734
2735       /* Let &* cancel out to simplify resulting code.  */
2736       if (TREE_CODE (arg) == INDIRECT_REF)
2737         {
2738           /* Don't let this be an lvalue.  */
2739           if (lvalue_p (TREE_OPERAND (arg, 0)))
2740             return non_lvalue (TREE_OPERAND (arg, 0));
2741           return TREE_OPERAND (arg, 0);
2742         }
2743
2744       /* For &x[y], return x+y */
2745       if (TREE_CODE (arg) == ARRAY_REF)
2746         {
2747           tree op0 = TREE_OPERAND (arg, 0);
2748           if (!c_mark_addressable (op0))
2749             return error_mark_node;
2750           return build_binary_op (PLUS_EXPR,
2751                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2752                                    ? array_to_pointer_conversion (op0)
2753                                    : op0),
2754                                   TREE_OPERAND (arg, 1), 1);
2755         }
2756
2757       /* Anything not already handled and not a true memory reference
2758          or a non-lvalue array is an error.  */
2759       else if (typecode != FUNCTION_TYPE && !flag
2760                && !lvalue_or_else (arg, lv_addressof))
2761         return error_mark_node;
2762
2763       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2764       argtype = TREE_TYPE (arg);
2765
2766       /* If the lvalue is const or volatile, merge that into the type
2767          to which the address will point.  Note that you can't get a
2768          restricted pointer by taking the address of something, so we
2769          only have to deal with `const' and `volatile' here.  */
2770       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2771           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2772           argtype = c_build_type_variant (argtype,
2773                                           TREE_READONLY (arg),
2774                                           TREE_THIS_VOLATILE (arg));
2775
2776       if (!c_mark_addressable (arg))
2777         return error_mark_node;
2778
2779       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2780                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2781
2782       argtype = build_pointer_type (argtype);
2783
2784       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2785          when we have proper support for integer constant expressions.  */
2786       val = get_base_address (arg);
2787       if (val && TREE_CODE (val) == INDIRECT_REF
2788           && integer_zerop (TREE_OPERAND (val, 0)))
2789         return fold_convert (argtype, fold_offsetof (arg));
2790
2791       val = build1 (ADDR_EXPR, argtype, arg);
2792
2793       return val;
2794
2795     default:
2796       break;
2797     }
2798
2799   if (argtype == 0)
2800     argtype = TREE_TYPE (arg);
2801   val = build1 (code, argtype, arg);
2802   return require_constant_value ? fold_initializer (val) : fold (val);
2803 }
2804
2805 /* Return nonzero if REF is an lvalue valid for this language.
2806    Lvalues can be assigned, unless their type has TYPE_READONLY.
2807    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2808
2809 static int
2810 lvalue_p (tree ref)
2811 {
2812   enum tree_code code = TREE_CODE (ref);
2813
2814   switch (code)
2815     {
2816     case REALPART_EXPR:
2817     case IMAGPART_EXPR:
2818     case COMPONENT_REF:
2819       return lvalue_p (TREE_OPERAND (ref, 0));
2820
2821     case COMPOUND_LITERAL_EXPR:
2822     case STRING_CST:
2823       return 1;
2824
2825     case INDIRECT_REF:
2826     case ARRAY_REF:
2827     case VAR_DECL:
2828     case PARM_DECL:
2829     case RESULT_DECL:
2830     case ERROR_MARK:
2831       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2832               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2833
2834     case BIND_EXPR:
2835       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2836
2837     default:
2838       return 0;
2839     }
2840 }
2841 \f
2842 /* Give an error for storing in something that is 'const'.  */
2843
2844 static void
2845 readonly_error (tree arg, enum lvalue_use use)
2846 {
2847   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement);
2848   /* Using this macro rather than (for example) arrays of messages
2849      ensures that all the format strings are checked at compile
2850      time.  */
2851 #define READONLY_MSG(A, I, D) (use == lv_assign                         \
2852                                ? (A)                                    \
2853                                : (use == lv_increment ? (I) : (D)))
2854   if (TREE_CODE (arg) == COMPONENT_REF)
2855     {
2856       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2857         readonly_error (TREE_OPERAND (arg, 0), use);
2858       else
2859         error (READONLY_MSG (G_("assignment of read-only member %qD"),
2860                              G_("increment of read-only member %qD"),
2861                              G_("decrement of read-only member %qD")),
2862                TREE_OPERAND (arg, 1));
2863     }
2864   else if (TREE_CODE (arg) == VAR_DECL)
2865     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
2866                          G_("increment of read-only variable %qD"),
2867                          G_("decrement of read-only variable %qD")),
2868            arg);
2869   else
2870     error (READONLY_MSG (G_("assignment of read-only location"),
2871                          G_("increment of read-only location"),
2872                          G_("decrement of read-only location")));
2873 }
2874
2875
2876 /* Return nonzero if REF is an lvalue valid for this language;
2877    otherwise, print an error message and return zero.  USE says
2878    how the lvalue is being used and so selects the error message.  */
2879
2880 static int
2881 lvalue_or_else (tree ref, enum lvalue_use use)
2882 {
2883   int win = lvalue_p (ref);
2884
2885   if (!win)
2886     lvalue_error (use);
2887
2888   return win;
2889 }
2890 \f
2891 /* Mark EXP saying that we need to be able to take the
2892    address of it; it should not be allocated in a register.
2893    Returns true if successful.  */
2894
2895 bool
2896 c_mark_addressable (tree exp)
2897 {
2898   tree x = exp;
2899
2900   while (1)
2901     switch (TREE_CODE (x))
2902       {
2903       case COMPONENT_REF:
2904         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2905           {
2906             error
2907               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
2908             return false;
2909           }
2910
2911         /* ... fall through ...  */
2912
2913       case ADDR_EXPR:
2914       case ARRAY_REF:
2915       case REALPART_EXPR:
2916       case IMAGPART_EXPR:
2917         x = TREE_OPERAND (x, 0);
2918         break;
2919
2920       case COMPOUND_LITERAL_EXPR:
2921       case CONSTRUCTOR:
2922         TREE_ADDRESSABLE (x) = 1;
2923         return true;
2924
2925       case VAR_DECL:
2926       case CONST_DECL:
2927       case PARM_DECL:
2928       case RESULT_DECL:
2929         if (C_DECL_REGISTER (x)
2930             && DECL_NONLOCAL (x))
2931           {
2932             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2933               {
2934                 error
2935                   ("global register variable %qD used in nested function", x);
2936                 return false;
2937               }
2938             pedwarn ("register variable %qD used in nested function", x);
2939           }
2940         else if (C_DECL_REGISTER (x))
2941           {
2942             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2943               error ("address of global register variable %qD requested", x);
2944             else
2945               error ("address of register variable %qD requested", x);
2946             return false;
2947           }
2948
2949         /* drops in */
2950       case FUNCTION_DECL:
2951         TREE_ADDRESSABLE (x) = 1;
2952         /* drops out */
2953       default:
2954         return true;
2955     }
2956 }
2957 \f
2958 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2959
2960 tree
2961 build_conditional_expr (tree ifexp, tree op1, tree op2)
2962 {
2963   tree type1;
2964   tree type2;
2965   enum tree_code code1;
2966   enum tree_code code2;
2967   tree result_type = NULL;
2968   tree orig_op1 = op1, orig_op2 = op2;
2969
2970   /* Promote both alternatives.  */
2971
2972   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
2973     op1 = default_conversion (op1);
2974   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
2975     op2 = default_conversion (op2);
2976
2977   if (TREE_CODE (ifexp) == ERROR_MARK
2978       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
2979       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
2980     return error_mark_node;
2981
2982   type1 = TREE_TYPE (op1);
2983   code1 = TREE_CODE (type1);
2984   type2 = TREE_TYPE (op2);
2985   code2 = TREE_CODE (type2);
2986
2987   /* C90 does not permit non-lvalue arrays in conditional expressions.
2988      In C99 they will be pointers by now.  */
2989   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
2990     {
2991       error ("non-lvalue array in conditional expression");
2992       return error_mark_node;
2993     }
2994
2995   /* Quickly detect the usual case where op1 and op2 have the same type
2996      after promotion.  */
2997   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
2998     {
2999       if (type1 == type2)
3000         result_type = type1;
3001       else
3002         result_type = TYPE_MAIN_VARIANT (type1);
3003     }
3004   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3005             || code1 == COMPLEX_TYPE)
3006            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3007                || code2 == COMPLEX_TYPE))
3008     {
3009       result_type = c_common_type (type1, type2);
3010
3011       /* If -Wsign-compare, warn here if type1 and type2 have
3012          different signedness.  We'll promote the signed to unsigned
3013          and later code won't know it used to be different.
3014          Do this check on the original types, so that explicit casts
3015          will be considered, but default promotions won't.  */
3016       if (warn_sign_compare && !skip_evaluation)
3017         {
3018           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3019           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3020
3021           if (unsigned_op1 ^ unsigned_op2)
3022             {
3023               /* Do not warn if the result type is signed, since the
3024                  signed type will only be chosen if it can represent
3025                  all the values of the unsigned type.  */
3026               if (!TYPE_UNSIGNED (result_type))
3027                 /* OK */;
3028               /* Do not warn if the signed quantity is an unsuffixed
3029                  integer literal (or some static constant expression
3030                  involving such literals) and it is non-negative.  */
3031               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3032                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3033                 /* OK */;
3034               else
3035                 warning (0, "signed and unsigned type in conditional expression");
3036             }
3037         }
3038     }
3039   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3040     {
3041       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3042         pedwarn ("ISO C forbids conditional expr with only one void side");
3043       result_type = void_type_node;
3044     }
3045   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3046     {
3047       if (comp_target_types (type1, type2))
3048         result_type = common_pointer_type (type1, type2);
3049       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3050                && TREE_CODE (orig_op1) != NOP_EXPR)
3051         result_type = qualify_type (type2, type1);
3052       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3053                && TREE_CODE (orig_op2) != NOP_EXPR)
3054         result_type = qualify_type (type1, type2);
3055       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3056         {
3057           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3058             pedwarn ("ISO C forbids conditional expr between "
3059                      "%<void *%> and function pointer");
3060           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3061                                                           TREE_TYPE (type2)));
3062         }
3063       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3064         {
3065           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3066             pedwarn ("ISO C forbids conditional expr between "
3067                      "%<void *%> and function pointer");
3068           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3069                                                           TREE_TYPE (type1)));
3070         }
3071       else
3072         {
3073           pedwarn ("pointer type mismatch in conditional expression");
3074           result_type = build_pointer_type (void_type_node);
3075         }
3076     }
3077   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3078     {
3079       if (!integer_zerop (op2))
3080         pedwarn ("pointer/integer type mismatch in conditional expression");
3081       else
3082         {
3083           op2 = null_pointer_node;
3084         }
3085       result_type = type1;
3086     }
3087   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3088     {
3089       if (!integer_zerop (op1))
3090         pedwarn ("pointer/integer type mismatch in conditional expression");
3091       else
3092         {
3093           op1 = null_pointer_node;
3094         }
3095       result_type = type2;
3096     }
3097
3098   if (!result_type)
3099     {
3100       if (flag_cond_mismatch)
3101         result_type = void_type_node;
3102       else
3103         {
3104           error ("type mismatch in conditional expression");
3105           return error_mark_node;
3106         }
3107     }
3108
3109   /* Merge const and volatile flags of the incoming types.  */
3110   result_type
3111     = build_type_variant (result_type,
3112                           TREE_READONLY (op1) || TREE_READONLY (op2),
3113                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3114
3115   if (result_type != TREE_TYPE (op1))
3116     op1 = convert_and_check (result_type, op1);
3117   if (result_type != TREE_TYPE (op2))
3118     op2 = convert_and_check (result_type, op2);
3119
3120   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3121 }
3122 \f
3123 /* Return a compound expression that performs two expressions and
3124    returns the value of the second of them.  */
3125
3126 tree
3127 build_compound_expr (tree expr1, tree expr2)
3128 {
3129   if (!TREE_SIDE_EFFECTS (expr1))
3130     {
3131       /* The left-hand operand of a comma expression is like an expression
3132          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3133          any side-effects, unless it was explicitly cast to (void).  */
3134       if (warn_unused_value)
3135         {
3136           if (VOID_TYPE_P (TREE_TYPE (expr1))
3137               && TREE_CODE (expr1) == CONVERT_EXPR)
3138             ; /* (void) a, b */
3139           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3140                    && TREE_CODE (expr1) == COMPOUND_EXPR
3141                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3142             ; /* (void) a, (void) b, c */
3143           else
3144             warning (0, "left-hand operand of comma expression has no effect");
3145         }
3146     }
3147
3148   /* With -Wunused, we should also warn if the left-hand operand does have
3149      side-effects, but computes a value which is not used.  For example, in
3150      `foo() + bar(), baz()' the result of the `+' operator is not used,
3151      so we should issue a warning.  */
3152   else if (warn_unused_value)
3153     warn_if_unused_value (expr1, input_location);
3154
3155   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3156 }
3157
3158 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3159
3160 tree
3161 build_c_cast (tree type, tree expr)
3162 {
3163   tree value = expr;
3164
3165   if (type == error_mark_node || expr == error_mark_node)
3166     return error_mark_node;
3167
3168   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3169      only in <protocol> qualifications.  But when constructing cast expressions,
3170      the protocols do matter and must be kept around.  */
3171   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3172     return build1 (NOP_EXPR, type, expr);
3173
3174   type = TYPE_MAIN_VARIANT (type);
3175
3176   if (TREE_CODE (type) == ARRAY_TYPE)
3177     {
3178       error ("cast specifies array type");
3179       return error_mark_node;
3180     }
3181
3182   if (TREE_CODE (type) == FUNCTION_TYPE)
3183     {
3184       error ("cast specifies function type");
3185       return error_mark_node;
3186     }
3187
3188   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3189     {
3190       if (pedantic)
3191         {
3192           if (TREE_CODE (type) == RECORD_TYPE
3193               || TREE_CODE (type) == UNION_TYPE)
3194             pedwarn ("ISO C forbids casting nonscalar to the same type");
3195         }
3196     }
3197   else if (TREE_CODE (type) == UNION_TYPE)
3198     {
3199       tree field;
3200
3201       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3202         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3203                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3204           break;
3205
3206       if (field)
3207         {
3208           tree t;
3209
3210           if (pedantic)
3211             pedwarn ("ISO C forbids casts to union type");
3212           t = digest_init (type,
3213                            build_constructor (type,
3214                                               build_tree_list (field, value)),
3215                            true, 0);
3216           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3217           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3218           return t;
3219         }
3220       error ("cast to union type from type not present in union");
3221       return error_mark_node;
3222     }
3223   else
3224     {
3225       tree otype, ovalue;
3226
3227       if (type == void_type_node)
3228         return build1 (CONVERT_EXPR, type, value);
3229
3230       otype = TREE_TYPE (value);
3231
3232       /* Optionally warn about potentially worrisome casts.  */
3233
3234       if (warn_cast_qual
3235           && TREE_CODE (type) == POINTER_TYPE
3236           && TREE_CODE (otype) == POINTER_TYPE)
3237         {
3238           tree in_type = type;
3239           tree in_otype = otype;
3240           int added = 0;
3241           int discarded = 0;
3242
3243           /* Check that the qualifiers on IN_TYPE are a superset of
3244              the qualifiers of IN_OTYPE.  The outermost level of
3245              POINTER_TYPE nodes is uninteresting and we stop as soon
3246              as we hit a non-POINTER_TYPE node on either type.  */
3247           do
3248             {
3249               in_otype = TREE_TYPE (in_otype);
3250               in_type = TREE_TYPE (in_type);
3251
3252               /* GNU C allows cv-qualified function types.  'const'
3253                  means the function is very pure, 'volatile' means it
3254                  can't return.  We need to warn when such qualifiers
3255                  are added, not when they're taken away.  */
3256               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3257                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3258                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3259               else
3260                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3261             }
3262           while (TREE_CODE (in_type) == POINTER_TYPE
3263                  && TREE_CODE (in_otype) == POINTER_TYPE);
3264
3265           if (added)
3266             warning (0, "cast adds new qualifiers to function type");
3267
3268           if (discarded)
3269             /* There are qualifiers present in IN_OTYPE that are not
3270                present in IN_TYPE.  */
3271             warning (0, "cast discards qualifiers from pointer target type");
3272         }
3273
3274       /* Warn about possible alignment problems.  */
3275       if (STRICT_ALIGNMENT
3276           && TREE_CODE (type) == POINTER_TYPE
3277           && TREE_CODE (otype) == POINTER_TYPE
3278           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3279           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3280           /* Don't warn about opaque types, where the actual alignment
3281              restriction is unknown.  */
3282           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3283                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3284                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3285           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3286         warning (OPT_Wcast_align,
3287                  "cast increases required alignment of target type");
3288
3289       if (TREE_CODE (type) == INTEGER_TYPE
3290           && TREE_CODE (otype) == POINTER_TYPE
3291           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3292           && !TREE_CONSTANT (value))
3293         warning (OPT_Wpointer_to_int_cast,
3294                  "cast from pointer to integer of different size");
3295
3296       if (TREE_CODE (value) == CALL_EXPR
3297           && TREE_CODE (type) != TREE_CODE (otype))
3298         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3299                  "to non-matching type %qT", otype, type);
3300
3301       if (TREE_CODE (type) == POINTER_TYPE
3302           && TREE_CODE (otype) == INTEGER_TYPE
3303           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3304           /* Don't warn about converting any constant.  */
3305           && !TREE_CONSTANT (value))
3306         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3307                  "of different size");
3308
3309       if (flag_strict_aliasing && warn_strict_aliasing
3310           && TREE_CODE (type) == POINTER_TYPE
3311           && TREE_CODE (otype) == POINTER_TYPE
3312           && TREE_CODE (expr) == ADDR_EXPR
3313           && (DECL_P (TREE_OPERAND (expr, 0))
3314               || TREE_CODE (TREE_OPERAND (expr, 0)) == COMPONENT_REF)
3315           && !VOID_TYPE_P (TREE_TYPE (type)))
3316         {
3317           /* Casting the address of an object to non void pointer. Warn
3318              if the cast breaks type based aliasing.  */
3319           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3320             warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
3321                      "might break strict-aliasing rules");
3322           else
3323             {
3324               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3325               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3326
3327               if (!alias_sets_conflict_p (set1, set2))
3328                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3329                          "pointer will break strict-aliasing rules");
3330               else if (warn_strict_aliasing > 1
3331                        && !alias_sets_might_conflict_p (set1, set2))
3332                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3333                          "pointer might break strict-aliasing rules");
3334             }
3335         }
3336
3337       /* If pedantic, warn for conversions between function and object
3338          pointer types, except for converting a null pointer constant
3339          to function pointer type.  */
3340       if (pedantic
3341           && TREE_CODE (type) == POINTER_TYPE
3342           && TREE_CODE (otype) == POINTER_TYPE
3343           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3344           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3345         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3346
3347       if (pedantic
3348           && TREE_CODE (type) == POINTER_TYPE
3349           && TREE_CODE (otype) == POINTER_TYPE
3350           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3351           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3352           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3353                && TREE_CODE (expr) != NOP_EXPR))
3354         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3355
3356       ovalue = value;
3357       value = convert (type, value);
3358
3359       /* Ignore any integer overflow caused by the cast.  */
3360       if (TREE_CODE (value) == INTEGER_CST)
3361         {
3362           /* If OVALUE had overflow set, then so will VALUE, so it
3363              is safe to overwrite.  */
3364           if (CONSTANT_CLASS_P (ovalue))
3365             {
3366               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3367               /* Similarly, constant_overflow cannot have become cleared.  */
3368               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3369             }
3370           else
3371             TREE_OVERFLOW (value) = 0;
3372         }
3373     }
3374
3375   /* Don't let a cast be an lvalue.  */
3376   if (value == expr)
3377     value = non_lvalue (value);
3378
3379   return value;
3380 }
3381
3382 /* Interpret a cast of expression EXPR to type TYPE.  */
3383 tree
3384 c_cast_expr (struct c_type_name *type_name, tree expr)
3385 {
3386   tree type;
3387   int saved_wsp = warn_strict_prototypes;
3388
3389   /* This avoids warnings about unprototyped casts on
3390      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3391   if (TREE_CODE (expr) == INTEGER_CST)
3392     warn_strict_prototypes = 0;
3393   type = groktypename (type_name);
3394   warn_strict_prototypes = saved_wsp;
3395
3396   return build_c_cast (type, expr);
3397 }
3398
3399 \f
3400 /* Build an assignment expression of lvalue LHS from value RHS.
3401    MODIFYCODE is the code for a binary operator that we use
3402    to combine the old value of LHS with RHS to get the new value.
3403    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3404
3405 tree
3406 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3407 {
3408   tree result;
3409   tree newrhs;
3410   tree lhstype = TREE_TYPE (lhs);
3411   tree olhstype = lhstype;
3412
3413   /* Types that aren't fully specified cannot be used in assignments.  */
3414   lhs = require_complete_type (lhs);
3415
3416   /* Avoid duplicate error messages from operands that had errors.  */
3417   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3418     return error_mark_node;
3419
3420   STRIP_TYPE_NOPS (rhs);
3421
3422   newrhs = rhs;
3423
3424   /* If a binary op has been requested, combine the old LHS value with the RHS
3425      producing the value we should actually store into the LHS.  */
3426
3427   if (modifycode != NOP_EXPR)
3428     {
3429       lhs = stabilize_reference (lhs);
3430       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3431     }
3432
3433   if (!lvalue_or_else (lhs, lv_assign))
3434     return error_mark_node;
3435
3436   /* Give an error for storing in something that is 'const'.  */
3437
3438   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3439       || ((TREE_CODE (lhstype) == RECORD_TYPE
3440            || TREE_CODE (lhstype) == UNION_TYPE)
3441           && C_TYPE_FIELDS_READONLY (lhstype)))
3442     readonly_error (lhs, lv_assign);
3443
3444   /* If storing into a structure or union member,
3445      it has probably been given type `int'.
3446      Compute the type that would go with
3447      the actual amount of storage the member occupies.  */
3448
3449   if (TREE_CODE (lhs) == COMPONENT_REF
3450       && (TREE_CODE (lhstype) == INTEGER_TYPE
3451           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3452           || TREE_CODE (lhstype) == REAL_TYPE
3453           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3454     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3455
3456   /* If storing in a field that is in actuality a short or narrower than one,
3457      we must store in the field in its actual type.  */
3458
3459   if (lhstype != TREE_TYPE (lhs))
3460     {
3461       lhs = copy_node (lhs);
3462       TREE_TYPE (lhs) = lhstype;
3463     }
3464
3465   /* Convert new value to destination type.  */
3466
3467   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3468                                    NULL_TREE, NULL_TREE, 0);
3469   if (TREE_CODE (newrhs) == ERROR_MARK)
3470     return error_mark_node;
3471
3472   /* Emit ObjC write barrier, if necessary.  */
3473   if (c_dialect_objc () && flag_objc_gc)
3474     {
3475       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3476       if (result)
3477         return result;
3478     }
3479
3480   /* Scan operands.  */
3481
3482   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3483   TREE_SIDE_EFFECTS (result) = 1;
3484
3485   /* If we got the LHS in a different type for storing in,
3486      convert the result back to the nominal type of LHS
3487      so that the value we return always has the same type
3488      as the LHS argument.  */
3489
3490   if (olhstype == TREE_TYPE (result))
3491     return result;
3492   return convert_for_assignment (olhstype, result, ic_assign,
3493                                  NULL_TREE, NULL_TREE, 0);
3494 }
3495 \f
3496 /* Convert value RHS to type TYPE as preparation for an assignment
3497    to an lvalue of type TYPE.
3498    The real work of conversion is done by `convert'.
3499    The purpose of this function is to generate error messages
3500    for assignments that are not allowed in C.
3501    ERRTYPE says whether it is argument passing, assignment,
3502    initialization or return.
3503
3504    FUNCTION is a tree for the function being called.
3505    PARMNUM is the number of the argument, for printing in error messages.  */
3506
3507 static tree
3508 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3509                         tree fundecl, tree function, int parmnum)
3510 {
3511   enum tree_code codel = TREE_CODE (type);
3512   tree rhstype;
3513   enum tree_code coder;
3514   tree rname = NULL_TREE;
3515   bool objc_ok = false;
3516
3517   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3518     {
3519       tree selector;
3520       /* Change pointer to function to the function itself for
3521          diagnostics.  */
3522       if (TREE_CODE (function) == ADDR_EXPR
3523           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3524         function = TREE_OPERAND (function, 0);
3525
3526       /* Handle an ObjC selector specially for diagnostics.  */
3527       selector = objc_message_selector ();
3528       rname = function;
3529       if (selector && parmnum > 2)
3530         {
3531           rname = selector;
3532           parmnum -= 2;
3533         }
3534     }
3535
3536   /* This macro is used to emit diagnostics to ensure that all format
3537      strings are complete sentences, visible to gettext and checked at
3538      compile time.  */
3539 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3540   do {                                          \
3541     switch (errtype)                            \
3542       {                                         \
3543       case ic_argpass:                          \
3544         pedwarn (AR, parmnum, rname);           \
3545         break;                                  \
3546       case ic_argpass_nonproto:                 \
3547         warning (0, AR, parmnum, rname);                \
3548         break;                                  \
3549       case ic_assign:                           \
3550         pedwarn (AS);                           \
3551         break;                                  \
3552       case ic_init:                             \
3553         pedwarn (IN);                           \
3554         break;                                  \
3555       case ic_return:                           \
3556         pedwarn (RE);                           \
3557         break;                                  \
3558       default:                                  \
3559         gcc_unreachable ();                     \
3560       }                                         \
3561   } while (0)
3562
3563   STRIP_TYPE_NOPS (rhs);
3564
3565   if (optimize && TREE_CODE (rhs) == VAR_DECL
3566            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3567     rhs = decl_constant_value_for_broken_optimization (rhs);
3568
3569   rhstype = TREE_TYPE (rhs);
3570   coder = TREE_CODE (rhstype);
3571
3572   if (coder == ERROR_MARK)
3573     return error_mark_node;
3574
3575   if (c_dialect_objc ())
3576     {
3577       int parmno;
3578
3579       switch (errtype)
3580         {
3581         case ic_return:
3582           parmno = 0;
3583           break;
3584
3585         case ic_assign:
3586           parmno = -1;
3587           break;
3588
3589         case ic_init:
3590           parmno = -2;
3591           break;
3592
3593         default:
3594           parmno = parmnum;
3595           break;
3596         }
3597
3598       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3599     }
3600
3601   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3602     {
3603       overflow_warning (rhs);
3604       return rhs;
3605     }
3606
3607   if (coder == VOID_TYPE)
3608     {
3609       /* Except for passing an argument to an unprototyped function,
3610          this is a constraint violation.  When passing an argument to
3611          an unprototyped function, it is compile-time undefined;
3612          making it a constraint in that case was rejected in
3613          DR#252.  */
3614       error ("void value not ignored as it ought to be");
3615       return error_mark_node;
3616     }
3617   /* A type converts to a reference to it.
3618      This code doesn't fully support references, it's just for the
3619      special case of va_start and va_copy.  */
3620   if (codel == REFERENCE_TYPE
3621       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3622     {
3623       if (!lvalue_p (rhs))
3624         {
3625           error ("cannot pass rvalue to reference parameter");
3626           return error_mark_node;
3627         }
3628       if (!c_mark_addressable (rhs))
3629         return error_mark_node;
3630       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3631
3632       /* We already know that these two types are compatible, but they
3633          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3634          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3635          likely to be va_list, a typedef to __builtin_va_list, which
3636          is different enough that it will cause problems later.  */
3637       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3638         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3639
3640       rhs = build1 (NOP_EXPR, type, rhs);
3641       return rhs;
3642     }
3643   /* Some types can interconvert without explicit casts.  */
3644   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3645            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3646     return convert (type, rhs);
3647   /* Arithmetic types all interconvert, and enum is treated like int.  */
3648   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3649             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3650             || codel == BOOLEAN_TYPE)
3651            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3652                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3653                || coder == BOOLEAN_TYPE))
3654     return convert_and_check (type, rhs);
3655
3656   /* Conversion to a transparent union from its member types.
3657      This applies only to function arguments.  */
3658   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3659            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3660     {
3661       tree memb_types;
3662       tree marginal_memb_type = 0;
3663
3664       for (memb_types = TYPE_FIELDS (type); memb_types;
3665            memb_types = TREE_CHAIN (memb_types))
3666         {
3667           tree memb_type = TREE_TYPE (memb_types);
3668
3669           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3670                          TYPE_MAIN_VARIANT (rhstype)))
3671             break;
3672
3673           if (TREE_CODE (memb_type) != POINTER_TYPE)
3674             continue;
3675
3676           if (coder == POINTER_TYPE)
3677             {
3678               tree ttl = TREE_TYPE (memb_type);
3679               tree ttr = TREE_TYPE (rhstype);
3680
3681               /* Any non-function converts to a [const][volatile] void *
3682                  and vice versa; otherwise, targets must be the same.
3683                  Meanwhile, the lhs target must have all the qualifiers of
3684                  the rhs.  */
3685               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3686                   || comp_target_types (memb_type, rhstype))
3687                 {
3688                   /* If this type won't generate any warnings, use it.  */
3689                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3690                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3691                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3692                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3693                              == TYPE_QUALS (ttr))
3694                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3695                              == TYPE_QUALS (ttl))))
3696                     break;
3697
3698                   /* Keep looking for a better type, but remember this one.  */
3699                   if (!marginal_memb_type)
3700                     marginal_memb_type = memb_type;
3701                 }
3702             }
3703
3704           /* Can convert integer zero to any pointer type.  */
3705           if (integer_zerop (rhs)
3706               || (TREE_CODE (rhs) == NOP_EXPR
3707                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3708             {
3709               rhs = null_pointer_node;
3710               break;
3711             }
3712         }
3713
3714       if (memb_types || marginal_memb_type)
3715         {
3716           if (!memb_types)
3717             {
3718               /* We have only a marginally acceptable member type;
3719                  it needs a warning.  */
3720               tree ttl = TREE_TYPE (marginal_memb_type);
3721               tree ttr = TREE_TYPE (rhstype);
3722
3723               /* Const and volatile mean something different for function
3724                  types, so the usual warnings are not appropriate.  */
3725               if (TREE_CODE (ttr) == FUNCTION_TYPE
3726                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3727                 {
3728                   /* Because const and volatile on functions are
3729                      restrictions that say the function will not do
3730                      certain things, it is okay to use a const or volatile
3731                      function where an ordinary one is wanted, but not
3732                      vice-versa.  */
3733                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3734                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3735                                             "makes qualified function "
3736                                             "pointer from unqualified"),
3737                                          G_("assignment makes qualified "
3738                                             "function pointer from "
3739                                             "unqualified"),
3740                                          G_("initialization makes qualified "
3741                                             "function pointer from "
3742                                             "unqualified"),
3743                                          G_("return makes qualified function "
3744                                             "pointer from unqualified"));
3745                 }
3746               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3747                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3748                                         "qualifiers from pointer target type"),
3749                                      G_("assignment discards qualifiers "
3750                                         "from pointer target type"),
3751                                      G_("initialization discards qualifiers "
3752                                         "from pointer target type"),
3753                                      G_("return discards qualifiers from "
3754                                         "pointer target type"));
3755             }
3756
3757           if (pedantic && !DECL_IN_SYSTEM_HEADER (fundecl))
3758             pedwarn ("ISO C prohibits argument conversion to union type");
3759
3760           return build1 (NOP_EXPR, type, rhs);
3761         }
3762     }
3763
3764   /* Conversions among pointers */
3765   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3766            && (coder == codel))
3767     {
3768       tree ttl = TREE_TYPE (type);
3769       tree ttr = TREE_TYPE (rhstype);
3770       tree mvl = ttl;
3771       tree mvr = ttr;
3772       bool is_opaque_pointer;
3773       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3774
3775       if (TREE_CODE (mvl) != ARRAY_TYPE)
3776         mvl = TYPE_MAIN_VARIANT (mvl);
3777       if (TREE_CODE (mvr) != ARRAY_TYPE)
3778         mvr = TYPE_MAIN_VARIANT (mvr);
3779       /* Opaque pointers are treated like void pointers.  */
3780       is_opaque_pointer = (targetm.vector_opaque_p (type)
3781                            || targetm.vector_opaque_p (rhstype))
3782         && TREE_CODE (ttl) == VECTOR_TYPE
3783         && TREE_CODE (ttr) == VECTOR_TYPE;
3784
3785       /* C++ does not allow the implicit conversion void* -> T*.  However,
3786          for the purpose of reducing the number of false positives, we
3787          tolerate the special case of
3788
3789                 int *p = NULL;
3790
3791          where NULL is typically defined in C to be '(void *) 0'.  */
3792       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3793         warning (OPT_Wc___compat, "request for implicit conversion from "
3794                  "%qT to %qT not permitted in C++", rhstype, type);
3795
3796       /* Any non-function converts to a [const][volatile] void *
3797          and vice versa; otherwise, targets must be the same.
3798          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3799       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3800           || (target_cmp = comp_target_types (type, rhstype))
3801           || is_opaque_pointer
3802           || (c_common_unsigned_type (mvl)
3803               == c_common_unsigned_type (mvr)))
3804         {
3805           if (pedantic
3806               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3807                   ||
3808                   (VOID_TYPE_P (ttr)
3809                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3810                       which are not ANSI null ptr constants.  */
3811                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3812                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3813             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3814                                     "%qE between function pointer "
3815                                     "and %<void *%>"),
3816                                  G_("ISO C forbids assignment between "
3817                                     "function pointer and %<void *%>"),
3818                                  G_("ISO C forbids initialization between "
3819                                     "function pointer and %<void *%>"),
3820                                  G_("ISO C forbids return between function "
3821                                     "pointer and %<void *%>"));
3822           /* Const and volatile mean something different for function types,
3823              so the usual warnings are not appropriate.  */
3824           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3825                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3826             {
3827               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3828                 {
3829                   /* Types differing only by the presence of the 'volatile'
3830                      qualifier are acceptable if the 'volatile' has been added
3831                      in by the Objective-C EH machinery.  */
3832                   if (!objc_type_quals_match (ttl, ttr))
3833                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3834                                             "qualifiers from pointer target type"),
3835                                          G_("assignment discards qualifiers "
3836                                             "from pointer target type"),
3837                                          G_("initialization discards qualifiers "
3838                                             "from pointer target type"),
3839                                          G_("return discards qualifiers from "
3840                                             "pointer target type"));
3841                 }
3842               /* If this is not a case of ignoring a mismatch in signedness,
3843                  no warning.  */
3844               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3845                        || target_cmp)
3846                 ;
3847               /* If there is a mismatch, do warn.  */
3848               else if (warn_pointer_sign)
3849                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
3850                                         "%d of %qE differ in signedness"),
3851                                      G_("pointer targets in assignment "
3852                                         "differ in signedness"),
3853                                      G_("pointer targets in initialization "
3854                                         "differ in signedness"),
3855                                      G_("pointer targets in return differ "
3856                                         "in signedness"));
3857             }
3858           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3859                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3860             {
3861               /* Because const and volatile on functions are restrictions
3862                  that say the function will not do certain things,
3863                  it is okay to use a const or volatile function
3864                  where an ordinary one is wanted, but not vice-versa.  */
3865               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3866                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3867                                         "qualified function pointer "
3868                                         "from unqualified"),
3869                                      G_("assignment makes qualified function "
3870                                         "pointer from unqualified"),
3871                                      G_("initialization makes qualified "
3872                                         "function pointer from unqualified"),
3873                                      G_("return makes qualified function "
3874                                         "pointer from unqualified"));
3875             }
3876         }
3877       else
3878         /* Avoid warning about the volatile ObjC EH puts on decls.  */
3879         if (!objc_ok)
3880           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
3881                                   "incompatible pointer type"),
3882                                G_("assignment from incompatible pointer type"),
3883                                G_("initialization from incompatible "
3884                                   "pointer type"),
3885                                G_("return from incompatible pointer type"));
3886
3887       return convert (type, rhs);
3888     }
3889   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3890     {
3891       /* ??? This should not be an error when inlining calls to
3892          unprototyped functions.  */
3893       error ("invalid use of non-lvalue array");
3894       return error_mark_node;
3895     }
3896   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3897     {
3898       /* An explicit constant 0 can convert to a pointer,
3899          or one that results from arithmetic, even including
3900          a cast to integer type.  */
3901       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3902           &&
3903           !(TREE_CODE (rhs) == NOP_EXPR
3904             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3905             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3906             && integer_zerop (TREE_OPERAND (rhs, 0))))
3907         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3908                                 "pointer from integer without a cast"),
3909                              G_("assignment makes pointer from integer "
3910                                 "without a cast"),
3911                              G_("initialization makes pointer from "
3912                                 "integer without a cast"),
3913                              G_("return makes pointer from integer "
3914                                 "without a cast"));
3915
3916       return convert (type, rhs);
3917     }
3918   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3919     {
3920       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
3921                               "from pointer without a cast"),
3922                            G_("assignment makes integer from pointer "
3923                               "without a cast"),
3924                            G_("initialization makes integer from pointer "
3925                               "without a cast"),
3926                            G_("return makes integer from pointer "
3927                               "without a cast"));
3928       return convert (type, rhs);
3929     }
3930   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3931     return convert (type, rhs);
3932
3933   switch (errtype)
3934     {
3935     case ic_argpass:
3936     case ic_argpass_nonproto:
3937       /* ??? This should not be an error when inlining calls to
3938          unprototyped functions.  */
3939       error ("incompatible type for argument %d of %qE", parmnum, rname);
3940       break;
3941     case ic_assign:
3942       error ("incompatible types in assignment");
3943       break;
3944     case ic_init:
3945       error ("incompatible types in initialization");
3946       break;
3947     case ic_return:
3948       error ("incompatible types in return");
3949       break;
3950     default:
3951       gcc_unreachable ();
3952     }
3953
3954   return error_mark_node;
3955 }
3956
3957 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
3958    is used for error and waring reporting and indicates which argument
3959    is being processed.  */
3960
3961 tree
3962 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
3963 {
3964   tree ret, type;
3965
3966   /* If FN was prototyped, the value has been converted already
3967      in convert_arguments.  */
3968   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
3969     return value;
3970
3971   type = TREE_TYPE (parm);
3972   ret = convert_for_assignment (type, value,
3973                                 ic_argpass_nonproto, fn,
3974                                 fn, argnum);
3975   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
3976       && INTEGRAL_TYPE_P (type)
3977       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3978     ret = default_conversion (ret);
3979   return ret;
3980 }
3981 \f
3982 /* If VALUE is a compound expr all of whose expressions are constant, then
3983    return its value.  Otherwise, return error_mark_node.
3984
3985    This is for handling COMPOUND_EXPRs as initializer elements
3986    which is allowed with a warning when -pedantic is specified.  */
3987
3988 static tree
3989 valid_compound_expr_initializer (tree value, tree endtype)
3990 {
3991   if (TREE_CODE (value) == COMPOUND_EXPR)
3992     {
3993       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
3994           == error_mark_node)
3995         return error_mark_node;
3996       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
3997                                               endtype);
3998     }
3999   else if (!initializer_constant_valid_p (value, endtype))
4000     return error_mark_node;
4001   else
4002     return value;
4003 }
4004 \f
4005 /* Perform appropriate conversions on the initial value of a variable,
4006    store it in the declaration DECL,
4007    and print any error messages that are appropriate.
4008    If the init is invalid, store an ERROR_MARK.  */
4009
4010 void
4011 store_init_value (tree decl, tree init)
4012 {
4013   tree value, type;
4014
4015   /* If variable's type was invalidly declared, just ignore it.  */
4016
4017   type = TREE_TYPE (decl);
4018   if (TREE_CODE (type) == ERROR_MARK)
4019     return;
4020
4021   /* Digest the specified initializer into an expression.  */
4022
4023   value = digest_init (type, init, true, TREE_STATIC (decl));
4024
4025   /* Store the expression if valid; else report error.  */
4026
4027   if (!in_system_header
4028       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4029     warning (OPT_Wtraditional, "traditional C rejects automatic "
4030              "aggregate initialization");
4031
4032   DECL_INITIAL (decl) = value;
4033
4034   /* ANSI wants warnings about out-of-range constant initializers.  */
4035   STRIP_TYPE_NOPS (value);
4036   constant_expression_warning (value);
4037
4038   /* Check if we need to set array size from compound literal size.  */
4039   if (TREE_CODE (type) == ARRAY_TYPE
4040       && TYPE_DOMAIN (type) == 0
4041       && value != error_mark_node)
4042     {
4043       tree inside_init = init;
4044
4045       STRIP_TYPE_NOPS (inside_init);
4046       inside_init = fold (inside_init);
4047
4048       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4049         {
4050           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4051
4052           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4053             {
4054               /* For int foo[] = (int [3]){1}; we need to set array size
4055                  now since later on array initializer will be just the
4056                  brace enclosed list of the compound literal.  */
4057               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4058               layout_type (type);
4059               layout_decl (decl, 0);
4060             }
4061         }
4062     }
4063 }
4064 \f
4065 /* Methods for storing and printing names for error messages.  */
4066
4067 /* Implement a spelling stack that allows components of a name to be pushed
4068    and popped.  Each element on the stack is this structure.  */
4069
4070 struct spelling
4071 {
4072   int kind;
4073   union
4074     {
4075       int i;
4076       const char *s;
4077     } u;
4078 };
4079
4080 #define SPELLING_STRING 1
4081 #define SPELLING_MEMBER 2
4082 #define SPELLING_BOUNDS 3
4083
4084 static struct spelling *spelling;       /* Next stack element (unused).  */
4085 static struct spelling *spelling_base;  /* Spelling stack base.  */
4086 static int spelling_size;               /* Size of the spelling stack.  */
4087
4088 /* Macros to save and restore the spelling stack around push_... functions.
4089    Alternative to SAVE_SPELLING_STACK.  */
4090
4091 #define SPELLING_DEPTH() (spelling - spelling_base)
4092 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4093
4094 /* Push an element on the spelling stack with type KIND and assign VALUE
4095    to MEMBER.  */
4096
4097 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4098 {                                                                       \
4099   int depth = SPELLING_DEPTH ();                                        \
4100                                                                         \
4101   if (depth >= spelling_size)                                           \
4102     {                                                                   \
4103       spelling_size += 10;                                              \
4104       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4105                                   spelling_size);                       \
4106       RESTORE_SPELLING_DEPTH (depth);                                   \
4107     }                                                                   \
4108                                                                         \
4109   spelling->kind = (KIND);                                              \
4110   spelling->MEMBER = (VALUE);                                           \
4111   spelling++;                                                           \
4112 }
4113
4114 /* Push STRING on the stack.  Printed literally.  */
4115
4116 static void
4117 push_string (const char *string)
4118 {
4119   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4120 }
4121
4122 /* Push a member name on the stack.  Printed as '.' STRING.  */
4123
4124 static void
4125 push_member_name (tree decl)
4126 {
4127   const char *const string
4128     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4129   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4130 }
4131
4132 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4133
4134 static void
4135 push_array_bounds (int bounds)
4136 {
4137   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4138 }
4139
4140 /* Compute the maximum size in bytes of the printed spelling.  */
4141
4142 static int
4143 spelling_length (void)
4144 {
4145   int size = 0;
4146   struct spelling *p;
4147
4148   for (p = spelling_base; p < spelling; p++)
4149     {
4150       if (p->kind == SPELLING_BOUNDS)
4151         size += 25;
4152       else
4153         size += strlen (p->u.s) + 1;
4154     }
4155
4156   return size;
4157 }
4158
4159 /* Print the spelling to BUFFER and return it.  */
4160
4161 static char *
4162 print_spelling (char *buffer)
4163 {
4164   char *d = buffer;
4165   struct spelling *p;
4166
4167   for (p = spelling_base; p < spelling; p++)
4168     if (p->kind == SPELLING_BOUNDS)
4169       {
4170         sprintf (d, "[%d]", p->u.i);
4171         d += strlen (d);
4172       }
4173     else
4174       {
4175         const char *s;
4176         if (p->kind == SPELLING_MEMBER)
4177           *d++ = '.';
4178         for (s = p->u.s; (*d = *s++); d++)
4179           ;
4180       }
4181   *d++ = '\0';
4182   return buffer;
4183 }
4184
4185 /* Issue an error message for a bad initializer component.
4186    MSGID identifies the message.
4187    The component name is taken from the spelling stack.  */
4188
4189 void
4190 error_init (const char *msgid)
4191 {
4192   char *ofwhat;
4193
4194   error ("%s", _(msgid));
4195   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4196   if (*ofwhat)
4197     error ("(near initialization for %qs)", ofwhat);
4198 }
4199
4200 /* Issue a pedantic warning for a bad initializer component.
4201    MSGID identifies the message.
4202    The component name is taken from the spelling stack.  */
4203
4204 void
4205 pedwarn_init (const char *msgid)
4206 {
4207   char *ofwhat;
4208
4209   pedwarn ("%s", _(msgid));
4210   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4211   if (*ofwhat)
4212     pedwarn ("(near initialization for %qs)", ofwhat);
4213 }
4214
4215 /* Issue a warning for a bad initializer component.
4216    MSGID identifies the message.
4217    The component name is taken from the spelling stack.  */
4218
4219 static void
4220 warning_init (const char *msgid)
4221 {
4222   char *ofwhat;
4223
4224   warning (0, "%s", _(msgid));
4225   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4226   if (*ofwhat)
4227     warning (0, "(near initialization for %qs)", ofwhat);
4228 }
4229 \f
4230 /* If TYPE is an array type and EXPR is a parenthesized string
4231    constant, warn if pedantic that EXPR is being used to initialize an
4232    object of type TYPE.  */
4233
4234 void
4235 maybe_warn_string_init (tree type, struct c_expr expr)
4236 {
4237   if (pedantic
4238       && TREE_CODE (type) == ARRAY_TYPE
4239       && TREE_CODE (expr.value) == STRING_CST
4240       && expr.original_code != STRING_CST)
4241     pedwarn_init ("array initialized from parenthesized string constant");
4242 }
4243
4244 /* Digest the parser output INIT as an initializer for type TYPE.
4245    Return a C expression of type TYPE to represent the initial value.
4246
4247    If INIT is a string constant, STRICT_STRING is true if it is
4248    unparenthesized or we should not warn here for it being parenthesized.
4249    For other types of INIT, STRICT_STRING is not used.
4250
4251    REQUIRE_CONSTANT requests an error if non-constant initializers or
4252    elements are seen.  */
4253
4254 static tree
4255 digest_init (tree type, tree init, bool strict_string, int require_constant)
4256 {
4257   enum tree_code code = TREE_CODE (type);
4258   tree inside_init = init;
4259
4260   if (type == error_mark_node
4261       || init == error_mark_node
4262       || TREE_TYPE (init) == error_mark_node)
4263     return error_mark_node;
4264
4265   STRIP_TYPE_NOPS (inside_init);
4266
4267   inside_init = fold (inside_init);
4268
4269   /* Initialization of an array of chars from a string constant
4270      optionally enclosed in braces.  */
4271
4272   if (code == ARRAY_TYPE && inside_init
4273       && TREE_CODE (inside_init) == STRING_CST)
4274     {
4275       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4276       /* Note that an array could be both an array of character type
4277          and an array of wchar_t if wchar_t is signed char or unsigned
4278          char.  */
4279       bool char_array = (typ1 == char_type_node
4280                          || typ1 == signed_char_type_node
4281                          || typ1 == unsigned_char_type_node);
4282       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4283       if (char_array || wchar_array)
4284         {
4285           struct c_expr expr;
4286           bool char_string;
4287           expr.value = inside_init;
4288           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4289           maybe_warn_string_init (type, expr);
4290
4291           char_string
4292             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4293                == char_type_node);
4294
4295           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4296                          TYPE_MAIN_VARIANT (type)))
4297             return inside_init;
4298
4299           if (!wchar_array && !char_string)
4300             {
4301               error_init ("char-array initialized from wide string");
4302               return error_mark_node;
4303             }
4304           if (char_string && !char_array)
4305             {
4306               error_init ("wchar_t-array initialized from non-wide string");
4307               return error_mark_node;
4308             }
4309
4310           TREE_TYPE (inside_init) = type;
4311           if (TYPE_DOMAIN (type) != 0
4312               && TYPE_SIZE (type) != 0
4313               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4314               /* Subtract 1 (or sizeof (wchar_t))
4315                  because it's ok to ignore the terminating null char
4316                  that is counted in the length of the constant.  */
4317               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4318                                        TREE_STRING_LENGTH (inside_init)
4319                                        - ((TYPE_PRECISION (typ1)
4320                                            != TYPE_PRECISION (char_type_node))
4321                                           ? (TYPE_PRECISION (wchar_type_node)
4322                                              / BITS_PER_UNIT)
4323                                           : 1)))
4324             pedwarn_init ("initializer-string for array of chars is too long");
4325
4326           return inside_init;
4327         }
4328       else if (INTEGRAL_TYPE_P (typ1))
4329         {
4330           error_init ("array of inappropriate type initialized "
4331                       "from string constant");
4332           return error_mark_node;
4333         }
4334     }
4335
4336   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4337      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4338      below and handle as a constructor.  */
4339   if (code == VECTOR_TYPE
4340       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4341       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4342       && TREE_CONSTANT (inside_init))
4343     {
4344       if (TREE_CODE (inside_init) == VECTOR_CST
4345           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4346                         TYPE_MAIN_VARIANT (type)))
4347         return inside_init;
4348
4349       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4350         {
4351           tree link;
4352
4353           /* Iterate through elements and check if all constructor
4354              elements are *_CSTs.  */
4355           for (link = CONSTRUCTOR_ELTS (inside_init);
4356                link;
4357                link = TREE_CHAIN (link))
4358             if (! CONSTANT_CLASS_P (TREE_VALUE (link)))
4359               break;
4360
4361           if (link == NULL)
4362             return build_vector (type, CONSTRUCTOR_ELTS (inside_init));
4363         }
4364     }
4365
4366   /* Any type can be initialized
4367      from an expression of the same type, optionally with braces.  */
4368
4369   if (inside_init && TREE_TYPE (inside_init) != 0
4370       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4371                      TYPE_MAIN_VARIANT (type))
4372           || (code == ARRAY_TYPE
4373               && comptypes (TREE_TYPE (inside_init), type))
4374           || (code == VECTOR_TYPE
4375               && comptypes (TREE_TYPE (inside_init), type))
4376           || (code == POINTER_TYPE
4377               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4378               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4379                             TREE_TYPE (type)))))
4380     {
4381       if (code == POINTER_TYPE)
4382         {
4383           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4384             {
4385               if (TREE_CODE (inside_init) == STRING_CST
4386                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4387                 inside_init = array_to_pointer_conversion (inside_init);
4388               else
4389                 {
4390                   error_init ("invalid use of non-lvalue array");
4391                   return error_mark_node;
4392                 }
4393             }
4394         }
4395
4396       if (code == VECTOR_TYPE)
4397         /* Although the types are compatible, we may require a
4398            conversion.  */
4399         inside_init = convert (type, inside_init);
4400
4401       if (require_constant && !flag_isoc99
4402           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4403         {
4404           /* As an extension, allow initializing objects with static storage
4405              duration with compound literals (which are then treated just as
4406              the brace enclosed list they contain).  */
4407           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4408           inside_init = DECL_INITIAL (decl);
4409         }
4410
4411       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4412           && TREE_CODE (inside_init) != CONSTRUCTOR)
4413         {
4414           error_init ("array initialized from non-constant array expression");
4415           return error_mark_node;
4416         }
4417
4418       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4419         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4420
4421       /* Compound expressions can only occur here if -pedantic or
4422          -pedantic-errors is specified.  In the later case, we always want
4423          an error.  In the former case, we simply want a warning.  */
4424       if (require_constant && pedantic
4425           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4426         {
4427           inside_init
4428             = valid_compound_expr_initializer (inside_init,
4429                                                TREE_TYPE (inside_init));
4430           if (inside_init == error_mark_node)
4431             error_init ("initializer element is not constant");
4432           else
4433             pedwarn_init ("initializer element is not constant");
4434           if (flag_pedantic_errors)
4435             inside_init = error_mark_node;
4436         }
4437       else if (require_constant
4438                && !initializer_constant_valid_p (inside_init,
4439                                                  TREE_TYPE (inside_init)))
4440         {
4441           error_init ("initializer element is not constant");
4442           inside_init = error_mark_node;
4443         }
4444
4445       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4446       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4447         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4448                                               NULL_TREE, 0);
4449       return inside_init;
4450     }
4451
4452   /* Handle scalar types, including conversions.  */
4453
4454   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4455       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4456       || code == VECTOR_TYPE)
4457     {
4458       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4459           && (TREE_CODE (init) == STRING_CST
4460               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4461         init = array_to_pointer_conversion (init);
4462       inside_init
4463         = convert_for_assignment (type, init, ic_init,
4464                                   NULL_TREE, NULL_TREE, 0);
4465
4466       /* Check to see if we have already given an error message.  */
4467       if (inside_init == error_mark_node)
4468         ;
4469       else if (require_constant && !TREE_CONSTANT (inside_init))
4470         {
4471           error_init ("initializer element is not constant");
4472           inside_init = error_mark_node;
4473         }
4474       else if (require_constant
4475                && !initializer_constant_valid_p (inside_init,
4476                                                  TREE_TYPE (inside_init)))
4477         {
4478           error_init ("initializer element is not computable at load time");
4479           inside_init = error_mark_node;
4480         }
4481
4482       return inside_init;
4483     }
4484
4485   /* Come here only for records and arrays.  */
4486
4487   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4488     {
4489       error_init ("variable-sized object may not be initialized");
4490       return error_mark_node;
4491     }
4492
4493   error_init ("invalid initializer");
4494   return error_mark_node;
4495 }
4496 \f
4497 /* Handle initializers that use braces.  */
4498
4499 /* Type of object we are accumulating a constructor for.
4500    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4501 static tree constructor_type;
4502
4503 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4504    left to fill.  */
4505 static tree constructor_fields;
4506
4507 /* For an ARRAY_TYPE, this is the specified index
4508    at which to store the next element we get.  */
4509 static tree constructor_index;
4510
4511 /* For an ARRAY_TYPE, this is the maximum index.  */
4512 static tree constructor_max_index;
4513
4514 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4515 static tree constructor_unfilled_fields;
4516
4517 /* For an ARRAY_TYPE, this is the index of the first element
4518    not yet written out.  */
4519 static tree constructor_unfilled_index;
4520
4521 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4522    This is so we can generate gaps between fields, when appropriate.  */
4523 static tree constructor_bit_index;
4524
4525 /* If we are saving up the elements rather than allocating them,
4526    this is the list of elements so far (in reverse order,
4527    most recent first).  */
4528 static tree constructor_elements;
4529
4530 /* 1 if constructor should be incrementally stored into a constructor chain,
4531    0 if all the elements should be kept in AVL tree.  */
4532 static int constructor_incremental;
4533
4534 /* 1 if so far this constructor's elements are all compile-time constants.  */
4535 static int constructor_constant;
4536
4537 /* 1 if so far this constructor's elements are all valid address constants.  */
4538 static int constructor_simple;
4539
4540 /* 1 if this constructor is erroneous so far.  */
4541 static int constructor_erroneous;
4542
4543 /* Structure for managing pending initializer elements, organized as an
4544    AVL tree.  */
4545
4546 struct init_node
4547 {
4548   struct init_node *left, *right;
4549   struct init_node *parent;
4550   int balance;
4551   tree purpose;
4552   tree value;
4553 };
4554
4555 /* Tree of pending elements at this constructor level.
4556    These are elements encountered out of order
4557    which belong at places we haven't reached yet in actually
4558    writing the output.
4559    Will never hold tree nodes across GC runs.  */
4560 static struct init_node *constructor_pending_elts;
4561
4562 /* The SPELLING_DEPTH of this constructor.  */
4563 static int constructor_depth;
4564
4565 /* DECL node for which an initializer is being read.
4566    0 means we are reading a constructor expression
4567    such as (struct foo) {...}.  */
4568 static tree constructor_decl;
4569
4570 /* Nonzero if this is an initializer for a top-level decl.  */
4571 static int constructor_top_level;
4572
4573 /* Nonzero if there were any member designators in this initializer.  */
4574 static int constructor_designated;
4575
4576 /* Nesting depth of designator list.  */
4577 static int designator_depth;
4578
4579 /* Nonzero if there were diagnosed errors in this designator list.  */
4580 static int designator_errorneous;
4581
4582 \f
4583 /* This stack has a level for each implicit or explicit level of
4584    structuring in the initializer, including the outermost one.  It
4585    saves the values of most of the variables above.  */
4586
4587 struct constructor_range_stack;
4588
4589 struct constructor_stack
4590 {
4591   struct constructor_stack *next;
4592   tree type;
4593   tree fields;
4594   tree index;
4595   tree max_index;
4596   tree unfilled_index;
4597   tree unfilled_fields;
4598   tree bit_index;
4599   tree elements;
4600   struct init_node *pending_elts;
4601   int offset;
4602   int depth;
4603   /* If value nonzero, this value should replace the entire
4604      constructor at this level.  */
4605   struct c_expr replacement_value;
4606   struct constructor_range_stack *range_stack;
4607   char constant;
4608   char simple;
4609   char implicit;
4610   char erroneous;
4611   char outer;
4612   char incremental;
4613   char designated;
4614 };
4615
4616 static struct constructor_stack *constructor_stack;
4617
4618 /* This stack represents designators from some range designator up to
4619    the last designator in the list.  */
4620
4621 struct constructor_range_stack
4622 {
4623   struct constructor_range_stack *next, *prev;
4624   struct constructor_stack *stack;
4625   tree range_start;
4626   tree index;
4627   tree range_end;
4628   tree fields;
4629 };
4630
4631 static struct constructor_range_stack *constructor_range_stack;
4632
4633 /* This stack records separate initializers that are nested.
4634    Nested initializers can't happen in ANSI C, but GNU C allows them
4635    in cases like { ... (struct foo) { ... } ... }.  */
4636
4637 struct initializer_stack
4638 {
4639   struct initializer_stack *next;
4640   tree decl;
4641   struct constructor_stack *constructor_stack;
4642   struct constructor_range_stack *constructor_range_stack;
4643   tree elements;
4644   struct spelling *spelling;
4645   struct spelling *spelling_base;
4646   int spelling_size;
4647   char top_level;
4648   char require_constant_value;
4649   char require_constant_elements;
4650 };
4651
4652 static struct initializer_stack *initializer_stack;
4653 \f
4654 /* Prepare to parse and output the initializer for variable DECL.  */
4655
4656 void
4657 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4658 {
4659   const char *locus;
4660   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4661
4662   p->decl = constructor_decl;
4663   p->require_constant_value = require_constant_value;
4664   p->require_constant_elements = require_constant_elements;
4665   p->constructor_stack = constructor_stack;
4666   p->constructor_range_stack = constructor_range_stack;
4667   p->elements = constructor_elements;
4668   p->spelling = spelling;
4669   p->spelling_base = spelling_base;
4670   p->spelling_size = spelling_size;
4671   p->top_level = constructor_top_level;
4672   p->next = initializer_stack;
4673   initializer_stack = p;
4674
4675   constructor_decl = decl;
4676   constructor_designated = 0;
4677   constructor_top_level = top_level;
4678
4679   if (decl != 0 && decl != error_mark_node)
4680     {
4681       require_constant_value = TREE_STATIC (decl);
4682       require_constant_elements
4683         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4684            /* For a scalar, you can always use any value to initialize,
4685               even within braces.  */
4686            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4687                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4688                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4689                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4690       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4691     }
4692   else
4693     {
4694       require_constant_value = 0;
4695       require_constant_elements = 0;
4696       locus = "(anonymous)";
4697     }
4698
4699   constructor_stack = 0;
4700   constructor_range_stack = 0;
4701
4702   missing_braces_mentioned = 0;
4703
4704   spelling_base = 0;
4705   spelling_size = 0;
4706   RESTORE_SPELLING_DEPTH (0);
4707
4708   if (locus)
4709     push_string (locus);
4710 }
4711
4712 void
4713 finish_init (void)
4714 {
4715   struct initializer_stack *p = initializer_stack;
4716
4717   /* Free the whole constructor stack of this initializer.  */
4718   while (constructor_stack)
4719     {
4720       struct constructor_stack *q = constructor_stack;
4721       constructor_stack = q->next;
4722       free (q);
4723     }
4724
4725   gcc_assert (!constructor_range_stack);
4726
4727   /* Pop back to the data of the outer initializer (if any).  */
4728   free (spelling_base);
4729
4730   constructor_decl = p->decl;
4731   require_constant_value = p->require_constant_value;
4732   require_constant_elements = p->require_constant_elements;
4733   constructor_stack = p->constructor_stack;
4734   constructor_range_stack = p->constructor_range_stack;
4735   constructor_elements = p->elements;
4736   spelling = p->spelling;
4737   spelling_base = p->spelling_base;
4738   spelling_size = p->spelling_size;
4739   constructor_top_level = p->top_level;
4740   initializer_stack = p->next;
4741   free (p);
4742 }
4743 \f
4744 /* Call here when we see the initializer is surrounded by braces.
4745    This is instead of a call to push_init_level;
4746    it is matched by a call to pop_init_level.
4747
4748    TYPE is the type to initialize, for a constructor expression.
4749    For an initializer for a decl, TYPE is zero.  */
4750
4751 void
4752 really_start_incremental_init (tree type)
4753 {
4754   struct constructor_stack *p = XNEW (struct constructor_stack);
4755
4756   if (type == 0)
4757     type = TREE_TYPE (constructor_decl);
4758
4759   if (targetm.vector_opaque_p (type))
4760     error ("opaque vector types cannot be initialized");
4761
4762   p->type = constructor_type;
4763   p->fields = constructor_fields;
4764   p->index = constructor_index;
4765   p->max_index = constructor_max_index;
4766   p->unfilled_index = constructor_unfilled_index;
4767   p->unfilled_fields = constructor_unfilled_fields;
4768   p->bit_index = constructor_bit_index;
4769   p->elements = constructor_elements;
4770   p->constant = constructor_constant;
4771   p->simple = constructor_simple;
4772   p->erroneous = constructor_erroneous;
4773   p->pending_elts = constructor_pending_elts;
4774   p->depth = constructor_depth;
4775   p->replacement_value.value = 0;
4776   p->replacement_value.original_code = ERROR_MARK;
4777   p->implicit = 0;
4778   p->range_stack = 0;
4779   p->outer = 0;
4780   p->incremental = constructor_incremental;
4781   p->designated = constructor_designated;
4782   p->next = 0;
4783   constructor_stack = p;
4784
4785   constructor_constant = 1;
4786   constructor_simple = 1;
4787   constructor_depth = SPELLING_DEPTH ();
4788   constructor_elements = 0;
4789   constructor_pending_elts = 0;
4790   constructor_type = type;
4791   constructor_incremental = 1;
4792   constructor_designated = 0;
4793   designator_depth = 0;
4794   designator_errorneous = 0;
4795
4796   if (TREE_CODE (constructor_type) == RECORD_TYPE
4797       || TREE_CODE (constructor_type) == UNION_TYPE)
4798     {
4799       constructor_fields = TYPE_FIELDS (constructor_type);
4800       /* Skip any nameless bit fields at the beginning.  */
4801       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4802              && DECL_NAME (constructor_fields) == 0)
4803         constructor_fields = TREE_CHAIN (constructor_fields);
4804
4805       constructor_unfilled_fields = constructor_fields;
4806       constructor_bit_index = bitsize_zero_node;
4807     }
4808   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4809     {
4810       if (TYPE_DOMAIN (constructor_type))
4811         {
4812           constructor_max_index
4813             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4814
4815           /* Detect non-empty initializations of zero-length arrays.  */
4816           if (constructor_max_index == NULL_TREE
4817               && TYPE_SIZE (constructor_type))
4818             constructor_max_index = build_int_cst (NULL_TREE, -1);
4819
4820           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4821              to initialize VLAs will cause a proper error; avoid tree
4822              checking errors as well by setting a safe value.  */
4823           if (constructor_max_index
4824               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4825             constructor_max_index = build_int_cst (NULL_TREE, -1);
4826
4827           constructor_index
4828             = convert (bitsizetype,
4829                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4830         }
4831       else
4832         {
4833           constructor_index = bitsize_zero_node;
4834           constructor_max_index = NULL_TREE;
4835         }
4836
4837       constructor_unfilled_index = constructor_index;
4838     }
4839   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4840     {
4841       /* Vectors are like simple fixed-size arrays.  */
4842       constructor_max_index =
4843         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4844       constructor_index = convert (bitsizetype, bitsize_zero_node);
4845       constructor_unfilled_index = constructor_index;
4846     }
4847   else
4848     {
4849       /* Handle the case of int x = {5}; */
4850       constructor_fields = constructor_type;
4851       constructor_unfilled_fields = constructor_type;
4852     }
4853 }
4854 \f
4855 /* Push down into a subobject, for initialization.
4856    If this is for an explicit set of braces, IMPLICIT is 0.
4857    If it is because the next element belongs at a lower level,
4858    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4859
4860 void
4861 push_init_level (int implicit)
4862 {
4863   struct constructor_stack *p;
4864   tree value = NULL_TREE;
4865
4866   /* If we've exhausted any levels that didn't have braces,
4867      pop them now.  If implicit == 1, this will have been done in
4868      process_init_element; do not repeat it here because in the case
4869      of excess initializers for an empty aggregate this leads to an
4870      infinite cycle of popping a level and immediately recreating
4871      it.  */
4872   if (implicit != 1)
4873     {
4874       while (constructor_stack->implicit)
4875         {
4876           if ((TREE_CODE (constructor_type) == RECORD_TYPE
4877                || TREE_CODE (constructor_type) == UNION_TYPE)
4878               && constructor_fields == 0)
4879             process_init_element (pop_init_level (1));
4880           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4881                    && constructor_max_index
4882                    && tree_int_cst_lt (constructor_max_index,
4883                                        constructor_index))
4884             process_init_element (pop_init_level (1));
4885           else
4886             break;
4887         }
4888     }
4889
4890   /* Unless this is an explicit brace, we need to preserve previous
4891      content if any.  */
4892   if (implicit)
4893     {
4894       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4895            || TREE_CODE (constructor_type) == UNION_TYPE)
4896           && constructor_fields)
4897         value = find_init_member (constructor_fields);
4898       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4899         value = find_init_member (constructor_index);
4900     }
4901
4902   p = XNEW (struct constructor_stack);
4903   p->type = constructor_type;
4904   p->fields = constructor_fields;
4905   p->index = constructor_index;
4906   p->max_index = constructor_max_index;
4907   p->unfilled_index = constructor_unfilled_index;
4908   p->unfilled_fields = constructor_unfilled_fields;
4909   p->bit_index = constructor_bit_index;
4910   p->elements = constructor_elements;
4911   p->constant = constructor_constant;
4912   p->simple = constructor_simple;
4913   p->erroneous = constructor_erroneous;
4914   p->pending_elts = constructor_pending_elts;
4915   p->depth = constructor_depth;
4916   p->replacement_value.value = 0;
4917   p->replacement_value.original_code = ERROR_MARK;
4918   p->implicit = implicit;
4919   p->outer = 0;
4920   p->incremental = constructor_incremental;
4921   p->designated = constructor_designated;
4922   p->next = constructor_stack;
4923   p->range_stack = 0;
4924   constructor_stack = p;
4925
4926   constructor_constant = 1;
4927   constructor_simple = 1;
4928   constructor_depth = SPELLING_DEPTH ();
4929   constructor_elements = 0;
4930   constructor_incremental = 1;
4931   constructor_designated = 0;
4932   constructor_pending_elts = 0;
4933   if (!implicit)
4934     {
4935       p->range_stack = constructor_range_stack;
4936       constructor_range_stack = 0;
4937       designator_depth = 0;
4938       designator_errorneous = 0;
4939     }
4940
4941   /* Don't die if an entire brace-pair level is superfluous
4942      in the containing level.  */
4943   if (constructor_type == 0)
4944     ;
4945   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4946            || TREE_CODE (constructor_type) == UNION_TYPE)
4947     {
4948       /* Don't die if there are extra init elts at the end.  */
4949       if (constructor_fields == 0)
4950         constructor_type = 0;
4951       else
4952         {
4953           constructor_type = TREE_TYPE (constructor_fields);
4954           push_member_name (constructor_fields);
4955           constructor_depth++;
4956         }
4957     }
4958   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4959     {
4960       constructor_type = TREE_TYPE (constructor_type);
4961       push_array_bounds (tree_low_cst (constructor_index, 0));
4962       constructor_depth++;
4963     }
4964
4965   if (constructor_type == 0)
4966     {
4967       error_init ("extra brace group at end of initializer");
4968       constructor_fields = 0;
4969       constructor_unfilled_fields = 0;
4970       return;
4971     }
4972
4973   if (value && TREE_CODE (value) == CONSTRUCTOR)
4974     {
4975       constructor_constant = TREE_CONSTANT (value);
4976       constructor_simple = TREE_STATIC (value);
4977       constructor_elements = CONSTRUCTOR_ELTS (value);
4978       if (constructor_elements
4979           && (TREE_CODE (constructor_type) == RECORD_TYPE
4980               || TREE_CODE (constructor_type) == ARRAY_TYPE))
4981         set_nonincremental_init ();
4982     }
4983
4984   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
4985     {
4986       missing_braces_mentioned = 1;
4987       warning_init ("missing braces around initializer");
4988     }
4989
4990   if (TREE_CODE (constructor_type) == RECORD_TYPE
4991            || TREE_CODE (constructor_type) == UNION_TYPE)
4992     {
4993       constructor_fields = TYPE_FIELDS (constructor_type);
4994       /* Skip any nameless bit fields at the beginning.  */
4995       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4996              && DECL_NAME (constructor_fields) == 0)
4997         constructor_fields = TREE_CHAIN (constructor_fields);
4998
4999       constructor_unfilled_fields = constructor_fields;
5000       constructor_bit_index = bitsize_zero_node;
5001     }
5002   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5003     {
5004       /* Vectors are like simple fixed-size arrays.  */
5005       constructor_max_index =
5006         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5007       constructor_index = convert (bitsizetype, integer_zero_node);
5008       constructor_unfilled_index = constructor_index;
5009     }
5010   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5011     {
5012       if (TYPE_DOMAIN (constructor_type))
5013         {
5014           constructor_max_index
5015             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5016
5017           /* Detect non-empty initializations of zero-length arrays.  */
5018           if (constructor_max_index == NULL_TREE
5019               && TYPE_SIZE (constructor_type))
5020             constructor_max_index = build_int_cst (NULL_TREE, -1);
5021
5022           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5023              to initialize VLAs will cause a proper error; avoid tree
5024              checking errors as well by setting a safe value.  */
5025           if (constructor_max_index
5026               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5027             constructor_max_index = build_int_cst (NULL_TREE, -1);
5028
5029           constructor_index
5030             = convert (bitsizetype,
5031                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5032         }
5033       else
5034         constructor_index = bitsize_zero_node;
5035
5036       constructor_unfilled_index = constructor_index;
5037       if (value && TREE_CODE (value) == STRING_CST)
5038         {
5039           /* We need to split the char/wchar array into individual
5040              characters, so that we don't have to special case it
5041              everywhere.  */
5042           set_nonincremental_init_from_string (value);
5043         }
5044     }
5045   else
5046     {
5047       if (constructor_type != error_mark_node)
5048         warning_init ("braces around scalar initializer");
5049       constructor_fields = constructor_type;
5050       constructor_unfilled_fields = constructor_type;
5051     }
5052 }
5053
5054 /* At the end of an implicit or explicit brace level,
5055    finish up that level of constructor.  If a single expression
5056    with redundant braces initialized that level, return the
5057    c_expr structure for that expression.  Otherwise, the original_code
5058    element is set to ERROR_MARK.
5059    If we were outputting the elements as they are read, return 0 as the value
5060    from inner levels (process_init_element ignores that),
5061    but return error_mark_node as the value from the outermost level
5062    (that's what we want to put in DECL_INITIAL).
5063    Otherwise, return a CONSTRUCTOR expression as the value.  */
5064
5065 struct c_expr
5066 pop_init_level (int implicit)
5067 {
5068   struct constructor_stack *p;
5069   struct c_expr ret;
5070   ret.value = 0;
5071   ret.original_code = ERROR_MARK;
5072
5073   if (implicit == 0)
5074     {
5075       /* When we come to an explicit close brace,
5076          pop any inner levels that didn't have explicit braces.  */
5077       while (constructor_stack->implicit)
5078         process_init_element (pop_init_level (1));
5079
5080       gcc_assert (!constructor_range_stack);
5081     }
5082
5083   /* Now output all pending elements.  */
5084   constructor_incremental = 1;
5085   output_pending_init_elements (1);
5086
5087   p = constructor_stack;
5088
5089   /* Error for initializing a flexible array member, or a zero-length
5090      array member in an inappropriate context.  */
5091   if (constructor_type && constructor_fields
5092       && TREE_CODE (constructor_type) == ARRAY_TYPE
5093       && TYPE_DOMAIN (constructor_type)
5094       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5095     {
5096       /* Silently discard empty initializations.  The parser will
5097          already have pedwarned for empty brackets.  */
5098       if (integer_zerop (constructor_unfilled_index))
5099         constructor_type = NULL_TREE;
5100       else
5101         {
5102           gcc_assert (!TYPE_SIZE (constructor_type));
5103
5104           if (constructor_depth > 2)
5105             error_init ("initialization of flexible array member in a nested context");
5106           else if (pedantic)
5107             pedwarn_init ("initialization of a flexible array member");
5108
5109           /* We have already issued an error message for the existence
5110              of a flexible array member not at the end of the structure.
5111              Discard the initializer so that we do not die later.  */
5112           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5113             constructor_type = NULL_TREE;
5114         }
5115     }
5116
5117   /* Warn when some struct elements are implicitly initialized to zero.  */
5118   if (warn_missing_field_initializers
5119       && constructor_type
5120       && TREE_CODE (constructor_type) == RECORD_TYPE
5121       && constructor_unfilled_fields)
5122     {
5123         /* Do not warn for flexible array members or zero-length arrays.  */
5124         while (constructor_unfilled_fields
5125                && (!DECL_SIZE (constructor_unfilled_fields)
5126                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5127           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5128
5129         /* Do not warn if this level of the initializer uses member
5130            designators; it is likely to be deliberate.  */
5131         if (constructor_unfilled_fields && !constructor_designated)
5132           {
5133             push_member_name (constructor_unfilled_fields);
5134             warning_init ("missing initializer");
5135             RESTORE_SPELLING_DEPTH (constructor_depth);
5136           }
5137     }
5138
5139   /* Pad out the end of the structure.  */
5140   if (p->replacement_value.value)
5141     /* If this closes a superfluous brace pair,
5142        just pass out the element between them.  */
5143     ret = p->replacement_value;
5144   else if (constructor_type == 0)
5145     ;
5146   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5147            && TREE_CODE (constructor_type) != UNION_TYPE
5148            && TREE_CODE (constructor_type) != ARRAY_TYPE
5149            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5150     {
5151       /* A nonincremental scalar initializer--just return
5152          the element, after verifying there is just one.  */
5153       if (constructor_elements == 0)
5154         {
5155           if (!constructor_erroneous)
5156             error_init ("empty scalar initializer");
5157           ret.value = error_mark_node;
5158         }
5159       else if (TREE_CHAIN (constructor_elements) != 0)
5160         {
5161           error_init ("extra elements in scalar initializer");
5162           ret.value = TREE_VALUE (constructor_elements);
5163         }
5164       else
5165         ret.value = TREE_VALUE (constructor_elements);
5166     }
5167   else
5168     {
5169       if (constructor_erroneous)
5170         ret.value = error_mark_node;
5171       else
5172         {
5173           ret.value = build_constructor (constructor_type,
5174                                          nreverse (constructor_elements));
5175           if (constructor_constant)
5176             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5177           if (constructor_constant && constructor_simple)
5178             TREE_STATIC (ret.value) = 1;
5179         }
5180     }
5181
5182   constructor_type = p->type;
5183   constructor_fields = p->fields;
5184   constructor_index = p->index;
5185   constructor_max_index = p->max_index;
5186   constructor_unfilled_index = p->unfilled_index;
5187   constructor_unfilled_fields = p->unfilled_fields;
5188   constructor_bit_index = p->bit_index;
5189   constructor_elements = p->elements;
5190   constructor_constant = p->constant;
5191   constructor_simple = p->simple;
5192   constructor_erroneous = p->erroneous;
5193   constructor_incremental = p->incremental;
5194   constructor_designated = p->designated;
5195   constructor_pending_elts = p->pending_elts;
5196   constructor_depth = p->depth;
5197   if (!p->implicit)
5198     constructor_range_stack = p->range_stack;
5199   RESTORE_SPELLING_DEPTH (constructor_depth);
5200
5201   constructor_stack = p->next;
5202   free (p);
5203
5204   if (ret.value == 0)
5205     {
5206       if (constructor_stack == 0)
5207         {
5208           ret.value = error_mark_node;
5209           return ret;
5210         }
5211       return ret;
5212     }
5213   return ret;
5214 }
5215
5216 /* Common handling for both array range and field name designators.
5217    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5218
5219 static int
5220 set_designator (int array)
5221 {
5222   tree subtype;
5223   enum tree_code subcode;
5224
5225   /* Don't die if an entire brace-pair level is superfluous
5226      in the containing level.  */
5227   if (constructor_type == 0)
5228     return 1;
5229
5230   /* If there were errors in this designator list already, bail out
5231      silently.  */
5232   if (designator_errorneous)
5233     return 1;
5234
5235   if (!designator_depth)
5236     {
5237       gcc_assert (!constructor_range_stack);
5238
5239       /* Designator list starts at the level of closest explicit
5240          braces.  */
5241       while (constructor_stack->implicit)
5242         process_init_element (pop_init_level (1));
5243       constructor_designated = 1;
5244       return 0;
5245     }
5246
5247   switch (TREE_CODE (constructor_type))
5248     {
5249     case  RECORD_TYPE:
5250     case  UNION_TYPE:
5251       subtype = TREE_TYPE (constructor_fields);
5252       if (subtype != error_mark_node)
5253         subtype = TYPE_MAIN_VARIANT (subtype);
5254       break;
5255     case ARRAY_TYPE:
5256       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5257       break;
5258     default:
5259       gcc_unreachable ();
5260     }
5261
5262   subcode = TREE_CODE (subtype);
5263   if (array && subcode != ARRAY_TYPE)
5264     {
5265       error_init ("array index in non-array initializer");
5266       return 1;
5267     }
5268   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5269     {
5270       error_init ("field name not in record or union initializer");
5271       return 1;
5272     }
5273
5274   constructor_designated = 1;
5275   push_init_level (2);
5276   return 0;
5277 }
5278
5279 /* If there are range designators in designator list, push a new designator
5280    to constructor_range_stack.  RANGE_END is end of such stack range or
5281    NULL_TREE if there is no range designator at this level.  */
5282
5283 static void
5284 push_range_stack (tree range_end)
5285 {
5286   struct constructor_range_stack *p;
5287
5288   p = GGC_NEW (struct constructor_range_stack);
5289   p->prev = constructor_range_stack;
5290   p->next = 0;
5291   p->fields = constructor_fields;
5292   p->range_start = constructor_index;
5293   p->index = constructor_index;
5294   p->stack = constructor_stack;
5295   p->range_end = range_end;
5296   if (constructor_range_stack)
5297     constructor_range_stack->next = p;
5298   constructor_range_stack = p;
5299 }
5300
5301 /* Within an array initializer, specify the next index to be initialized.
5302    FIRST is that index.  If LAST is nonzero, then initialize a range
5303    of indices, running from FIRST through LAST.  */
5304
5305 void
5306 set_init_index (tree first, tree last)
5307 {
5308   if (set_designator (1))
5309     return;
5310
5311   designator_errorneous = 1;
5312
5313   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5314       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5315     {
5316       error_init ("array index in initializer not of integer type");
5317       return;
5318     }
5319
5320   if (TREE_CODE (first) != INTEGER_CST)
5321     error_init ("nonconstant array index in initializer");
5322   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5323     error_init ("nonconstant array index in initializer");
5324   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5325     error_init ("array index in non-array initializer");
5326   else if (tree_int_cst_sgn (first) == -1)
5327     error_init ("array index in initializer exceeds array bounds");
5328   else if (constructor_max_index
5329            && tree_int_cst_lt (constructor_max_index, first))
5330     error_init ("array index in initializer exceeds array bounds");
5331   else
5332     {
5333       constructor_index = convert (bitsizetype, first);
5334
5335       if (last)
5336         {
5337           if (tree_int_cst_equal (first, last))
5338             last = 0;
5339           else if (tree_int_cst_lt (last, first))
5340             {
5341               error_init ("empty index range in initializer");
5342               last = 0;
5343             }
5344           else
5345             {
5346               last = convert (bitsizetype, last);
5347               if (constructor_max_index != 0
5348                   && tree_int_cst_lt (constructor_max_index, last))
5349                 {
5350                   error_init ("array index range in initializer exceeds array bounds");
5351                   last = 0;
5352                 }
5353             }
5354         }
5355
5356       designator_depth++;
5357       designator_errorneous = 0;
5358       if (constructor_range_stack || last)
5359         push_range_stack (last);
5360     }
5361 }
5362
5363 /* Within a struct initializer, specify the next field to be initialized.  */
5364
5365 void
5366 set_init_label (tree fieldname)
5367 {
5368   tree tail;
5369
5370   if (set_designator (0))
5371     return;
5372
5373   designator_errorneous = 1;
5374
5375   if (TREE_CODE (constructor_type) != RECORD_TYPE
5376       && TREE_CODE (constructor_type) != UNION_TYPE)
5377     {
5378       error_init ("field name not in record or union initializer");
5379       return;
5380     }
5381
5382   for (tail = TYPE_FIELDS (constructor_type); tail;
5383        tail = TREE_CHAIN (tail))
5384     {
5385       if (DECL_NAME (tail) == fieldname)
5386         break;
5387     }
5388
5389   if (tail == 0)
5390     error ("unknown field %qE specified in initializer", fieldname);
5391   else
5392     {
5393       constructor_fields = tail;
5394       designator_depth++;
5395       designator_errorneous = 0;
5396       if (constructor_range_stack)
5397         push_range_stack (NULL_TREE);
5398     }
5399 }
5400 \f
5401 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5402    identifies the initializer, either array index or field in a structure.
5403    VALUE is the value of that index or field.  */
5404
5405 static void
5406 add_pending_init (tree purpose, tree value)
5407 {
5408   struct init_node *p, **q, *r;
5409
5410   q = &constructor_pending_elts;
5411   p = 0;
5412
5413   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5414     {
5415       while (*q != 0)
5416         {
5417           p = *q;
5418           if (tree_int_cst_lt (purpose, p->purpose))
5419             q = &p->left;
5420           else if (tree_int_cst_lt (p->purpose, purpose))
5421             q = &p->right;
5422           else
5423             {
5424               if (TREE_SIDE_EFFECTS (p->value))
5425                 warning_init ("initialized field with side-effects overwritten");
5426               p->value = value;
5427               return;
5428             }
5429         }
5430     }
5431   else
5432     {
5433       tree bitpos;
5434
5435       bitpos = bit_position (purpose);
5436       while (*q != NULL)
5437         {
5438           p = *q;
5439           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5440             q = &p->left;
5441           else if (p->purpose != purpose)
5442             q = &p->right;
5443           else
5444             {
5445               if (TREE_SIDE_EFFECTS (p->value))
5446                 warning_init ("initialized field with side-effects overwritten");
5447               p->value = value;
5448               return;
5449             }
5450         }
5451     }
5452
5453   r = GGC_NEW (struct init_node);
5454   r->purpose = purpose;
5455   r->value = value;
5456
5457   *q = r;
5458   r->parent = p;
5459   r->left = 0;
5460   r->right = 0;
5461   r->balance = 0;
5462
5463   while (p)
5464     {
5465       struct init_node *s;
5466
5467       if (r == p->left)
5468         {
5469           if (p->balance == 0)
5470             p->balance = -1;
5471           else if (p->balance < 0)
5472             {
5473               if (r->balance < 0)
5474                 {
5475                   /* L rotation.  */
5476                   p->left = r->right;
5477                   if (p->left)
5478                     p->left->parent = p;
5479                   r->right = p;
5480
5481                   p->balance = 0;
5482                   r->balance = 0;
5483
5484                   s = p->parent;
5485                   p->parent = r;
5486                   r->parent = s;
5487                   if (s)
5488                     {
5489                       if (s->left == p)
5490                         s->left = r;
5491                       else
5492                         s->right = r;
5493                     }
5494                   else
5495                     constructor_pending_elts = r;
5496                 }
5497               else
5498                 {
5499                   /* LR rotation.  */
5500                   struct init_node *t = r->right;
5501
5502                   r->right = t->left;
5503                   if (r->right)
5504                     r->right->parent = r;
5505                   t->left = r;
5506
5507                   p->left = t->right;
5508                   if (p->left)
5509                     p->left->parent = p;
5510                   t->right = p;
5511
5512                   p->balance = t->balance < 0;
5513                   r->balance = -(t->balance > 0);
5514                   t->balance = 0;
5515
5516                   s = p->parent;
5517                   p->parent = t;
5518                   r->parent = t;
5519                   t->parent = s;
5520                   if (s)
5521                     {
5522                       if (s->left == p)
5523                         s->left = t;
5524                       else
5525                         s->right = t;
5526                     }
5527                   else
5528                     constructor_pending_elts = t;
5529                 }
5530               break;
5531             }
5532           else
5533             {
5534               /* p->balance == +1; growth of left side balances the node.  */
5535               p->balance = 0;
5536               break;
5537             }
5538         }
5539       else /* r == p->right */
5540         {
5541           if (p->balance == 0)
5542             /* Growth propagation from right side.  */
5543             p->balance++;
5544           else if (p->balance > 0)
5545             {
5546               if (r->balance > 0)
5547                 {
5548                   /* R rotation.  */
5549                   p->right = r->left;
5550                   if (p->right)
5551                     p->right->parent = p;
5552                   r->left = p;
5553
5554                   p->balance = 0;
5555                   r->balance = 0;
5556
5557                   s = p->parent;
5558                   p->parent = r;
5559                   r->parent = s;
5560                   if (s)
5561                     {
5562                       if (s->left == p)
5563                         s->left = r;
5564                       else
5565                         s->right = r;
5566                     }
5567                   else
5568                     constructor_pending_elts = r;
5569                 }
5570               else /* r->balance == -1 */
5571                 {
5572                   /* RL rotation */
5573                   struct init_node *t = r->left;
5574
5575                   r->left = t->right;
5576                   if (r->left)
5577                     r->left->parent = r;
5578                   t->right = r;
5579
5580                   p->right = t->left;
5581                   if (p->right)
5582                     p->right->parent = p;
5583                   t->left = p;
5584
5585                   r->balance = (t->balance < 0);
5586                   p->balance = -(t->balance > 0);
5587                   t->balance = 0;
5588
5589                   s = p->parent;
5590                   p->parent = t;
5591                   r->parent = t;
5592                   t->parent = s;
5593                   if (s)
5594                     {
5595                       if (s->left == p)
5596                         s->left = t;
5597                       else
5598                         s->right = t;
5599                     }
5600                   else
5601                     constructor_pending_elts = t;
5602                 }
5603               break;
5604             }
5605           else
5606             {
5607               /* p->balance == -1; growth of right side balances the node.  */
5608               p->balance = 0;
5609               break;
5610             }
5611         }
5612
5613       r = p;
5614       p = p->parent;
5615     }
5616 }
5617
5618 /* Build AVL tree from a sorted chain.  */
5619
5620 static void
5621 set_nonincremental_init (void)
5622 {
5623   tree chain;
5624
5625   if (TREE_CODE (constructor_type) != RECORD_TYPE
5626       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5627     return;
5628
5629   for (chain = constructor_elements; chain; chain = TREE_CHAIN (chain))
5630     add_pending_init (TREE_PURPOSE (chain), TREE_VALUE (chain));
5631   constructor_elements = 0;
5632   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5633     {
5634       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5635       /* Skip any nameless bit fields at the beginning.  */
5636       while (constructor_unfilled_fields != 0
5637              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5638              && DECL_NAME (constructor_unfilled_fields) == 0)
5639         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5640
5641     }
5642   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5643     {
5644       if (TYPE_DOMAIN (constructor_type))
5645         constructor_unfilled_index
5646             = convert (bitsizetype,
5647                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5648       else
5649         constructor_unfilled_index = bitsize_zero_node;
5650     }
5651   constructor_incremental = 0;
5652 }
5653
5654 /* Build AVL tree from a string constant.  */
5655
5656 static void
5657 set_nonincremental_init_from_string (tree str)
5658 {
5659   tree value, purpose, type;
5660   HOST_WIDE_INT val[2];
5661   const char *p, *end;
5662   int byte, wchar_bytes, charwidth, bitpos;
5663
5664   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5665
5666   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5667       == TYPE_PRECISION (char_type_node))
5668     wchar_bytes = 1;
5669   else
5670     {
5671       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5672                   == TYPE_PRECISION (wchar_type_node));
5673       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5674     }
5675   charwidth = TYPE_PRECISION (char_type_node);
5676   type = TREE_TYPE (constructor_type);
5677   p = TREE_STRING_POINTER (str);
5678   end = p + TREE_STRING_LENGTH (str);
5679
5680   for (purpose = bitsize_zero_node;
5681        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5682        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5683     {
5684       if (wchar_bytes == 1)
5685         {
5686           val[1] = (unsigned char) *p++;
5687           val[0] = 0;
5688         }
5689       else
5690         {
5691           val[0] = 0;
5692           val[1] = 0;
5693           for (byte = 0; byte < wchar_bytes; byte++)
5694             {
5695               if (BYTES_BIG_ENDIAN)
5696                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5697               else
5698                 bitpos = byte * charwidth;
5699               val[bitpos < HOST_BITS_PER_WIDE_INT]
5700                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5701                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5702             }
5703         }
5704
5705       if (!TYPE_UNSIGNED (type))
5706         {
5707           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5708           if (bitpos < HOST_BITS_PER_WIDE_INT)
5709             {
5710               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5711                 {
5712                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5713                   val[0] = -1;
5714                 }
5715             }
5716           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5717             {
5718               if (val[1] < 0)
5719                 val[0] = -1;
5720             }
5721           else if (val[0] & (((HOST_WIDE_INT) 1)
5722                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5723             val[0] |= ((HOST_WIDE_INT) -1)
5724                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5725         }
5726
5727       value = build_int_cst_wide (type, val[1], val[0]);
5728       add_pending_init (purpose, value);
5729     }
5730
5731   constructor_incremental = 0;
5732 }
5733
5734 /* Return value of FIELD in pending initializer or zero if the field was
5735    not initialized yet.  */
5736
5737 static tree
5738 find_init_member (tree field)
5739 {
5740   struct init_node *p;
5741
5742   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5743     {
5744       if (constructor_incremental
5745           && tree_int_cst_lt (field, constructor_unfilled_index))
5746         set_nonincremental_init ();
5747
5748       p = constructor_pending_elts;
5749       while (p)
5750         {
5751           if (tree_int_cst_lt (field, p->purpose))
5752             p = p->left;
5753           else if (tree_int_cst_lt (p->purpose, field))
5754             p = p->right;
5755           else
5756             return p->value;
5757         }
5758     }
5759   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5760     {
5761       tree bitpos = bit_position (field);
5762
5763       if (constructor_incremental
5764           && (!constructor_unfilled_fields
5765               || tree_int_cst_lt (bitpos,
5766                                   bit_position (constructor_unfilled_fields))))
5767         set_nonincremental_init ();
5768
5769       p = constructor_pending_elts;
5770       while (p)
5771         {
5772           if (field == p->purpose)
5773             return p->value;
5774           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5775             p = p->left;
5776           else
5777             p = p->right;
5778         }
5779     }
5780   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5781     {
5782       if (constructor_elements
5783           && TREE_PURPOSE (constructor_elements) == field)
5784         return TREE_VALUE (constructor_elements);
5785     }
5786   return 0;
5787 }
5788
5789 /* "Output" the next constructor element.
5790    At top level, really output it to assembler code now.
5791    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5792    TYPE is the data type that the containing data type wants here.
5793    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5794    If VALUE is a string constant, STRICT_STRING is true if it is
5795    unparenthesized or we should not warn here for it being parenthesized.
5796    For other types of VALUE, STRICT_STRING is not used.
5797
5798    PENDING if non-nil means output pending elements that belong
5799    right after this element.  (PENDING is normally 1;
5800    it is 0 while outputting pending elements, to avoid recursion.)  */
5801
5802 static void
5803 output_init_element (tree value, bool strict_string, tree type, tree field,
5804                      int pending)
5805 {
5806   if (type == error_mark_node || value == error_mark_node)
5807     {
5808       constructor_erroneous = 1;
5809       return;
5810     }
5811   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5812       && (TREE_CODE (value) == STRING_CST
5813           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5814       && !(TREE_CODE (value) == STRING_CST
5815            && TREE_CODE (type) == ARRAY_TYPE
5816            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5817       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5818                      TYPE_MAIN_VARIANT (type)))
5819     value = array_to_pointer_conversion (value);
5820
5821   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5822       && require_constant_value && !flag_isoc99 && pending)
5823     {
5824       /* As an extension, allow initializing objects with static storage
5825          duration with compound literals (which are then treated just as
5826          the brace enclosed list they contain).  */
5827       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5828       value = DECL_INITIAL (decl);
5829     }
5830
5831   if (value == error_mark_node)
5832     constructor_erroneous = 1;
5833   else if (!TREE_CONSTANT (value))
5834     constructor_constant = 0;
5835   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
5836            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5837                 || TREE_CODE (constructor_type) == UNION_TYPE)
5838                && DECL_C_BIT_FIELD (field)
5839                && TREE_CODE (value) != INTEGER_CST))
5840     constructor_simple = 0;
5841
5842   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
5843     {
5844       if (require_constant_value)
5845         {
5846           error_init ("initializer element is not constant");
5847           value = error_mark_node;
5848         }
5849       else if (require_constant_elements)
5850         pedwarn ("initializer element is not computable at load time");
5851     }
5852
5853   /* If this field is empty (and not at the end of structure),
5854      don't do anything other than checking the initializer.  */
5855   if (field
5856       && (TREE_TYPE (field) == error_mark_node
5857           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5858               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5859               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5860                   || TREE_CHAIN (field)))))
5861     return;
5862
5863   value = digest_init (type, value, strict_string, require_constant_value);
5864   if (value == error_mark_node)
5865     {
5866       constructor_erroneous = 1;
5867       return;
5868     }
5869
5870   /* If this element doesn't come next in sequence,
5871      put it on constructor_pending_elts.  */
5872   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5873       && (!constructor_incremental
5874           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5875     {
5876       if (constructor_incremental
5877           && tree_int_cst_lt (field, constructor_unfilled_index))
5878         set_nonincremental_init ();
5879
5880       add_pending_init (field, value);
5881       return;
5882     }
5883   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5884            && (!constructor_incremental
5885                || field != constructor_unfilled_fields))
5886     {
5887       /* We do this for records but not for unions.  In a union,
5888          no matter which field is specified, it can be initialized
5889          right away since it starts at the beginning of the union.  */
5890       if (constructor_incremental)
5891         {
5892           if (!constructor_unfilled_fields)
5893             set_nonincremental_init ();
5894           else
5895             {
5896               tree bitpos, unfillpos;
5897
5898               bitpos = bit_position (field);
5899               unfillpos = bit_position (constructor_unfilled_fields);
5900
5901               if (tree_int_cst_lt (bitpos, unfillpos))
5902                 set_nonincremental_init ();
5903             }
5904         }
5905
5906       add_pending_init (field, value);
5907       return;
5908     }
5909   else if (TREE_CODE (constructor_type) == UNION_TYPE
5910            && constructor_elements)
5911     {
5912       if (TREE_SIDE_EFFECTS (TREE_VALUE (constructor_elements)))
5913         warning_init ("initialized field with side-effects overwritten");
5914
5915       /* We can have just one union field set.  */
5916       constructor_elements = 0;
5917     }
5918
5919   /* Otherwise, output this element either to
5920      constructor_elements or to the assembler file.  */
5921
5922   if (field && TREE_CODE (field) == INTEGER_CST)
5923     field = copy_node (field);
5924   constructor_elements
5925     = tree_cons (field, value, constructor_elements);
5926
5927   /* Advance the variable that indicates sequential elements output.  */
5928   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5929     constructor_unfilled_index
5930       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5931                     bitsize_one_node);
5932   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5933     {
5934       constructor_unfilled_fields
5935         = TREE_CHAIN (constructor_unfilled_fields);
5936
5937       /* Skip any nameless bit fields.  */
5938       while (constructor_unfilled_fields != 0
5939              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5940              && DECL_NAME (constructor_unfilled_fields) == 0)
5941         constructor_unfilled_fields =
5942           TREE_CHAIN (constructor_unfilled_fields);
5943     }
5944   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5945     constructor_unfilled_fields = 0;
5946
5947   /* Now output any pending elements which have become next.  */
5948   if (pending)
5949     output_pending_init_elements (0);
5950 }
5951
5952 /* Output any pending elements which have become next.
5953    As we output elements, constructor_unfilled_{fields,index}
5954    advances, which may cause other elements to become next;
5955    if so, they too are output.
5956
5957    If ALL is 0, we return when there are
5958    no more pending elements to output now.
5959
5960    If ALL is 1, we output space as necessary so that
5961    we can output all the pending elements.  */
5962
5963 static void
5964 output_pending_init_elements (int all)
5965 {
5966   struct init_node *elt = constructor_pending_elts;
5967   tree next;
5968
5969  retry:
5970
5971   /* Look through the whole pending tree.
5972      If we find an element that should be output now,
5973      output it.  Otherwise, set NEXT to the element
5974      that comes first among those still pending.  */
5975
5976   next = 0;
5977   while (elt)
5978     {
5979       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5980         {
5981           if (tree_int_cst_equal (elt->purpose,
5982                                   constructor_unfilled_index))
5983             output_init_element (elt->value, true,
5984                                  TREE_TYPE (constructor_type),
5985                                  constructor_unfilled_index, 0);
5986           else if (tree_int_cst_lt (constructor_unfilled_index,
5987                                     elt->purpose))
5988             {
5989               /* Advance to the next smaller node.  */
5990               if (elt->left)
5991                 elt = elt->left;
5992               else
5993                 {
5994                   /* We have reached the smallest node bigger than the
5995                      current unfilled index.  Fill the space first.  */
5996                   next = elt->purpose;
5997                   break;
5998                 }
5999             }
6000           else
6001             {
6002               /* Advance to the next bigger node.  */
6003               if (elt->right)
6004                 elt = elt->right;
6005               else
6006                 {
6007                   /* We have reached the biggest node in a subtree.  Find
6008                      the parent of it, which is the next bigger node.  */
6009                   while (elt->parent && elt->parent->right == elt)
6010                     elt = elt->parent;
6011                   elt = elt->parent;
6012                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6013                                               elt->purpose))
6014                     {
6015                       next = elt->purpose;
6016                       break;
6017                     }
6018                 }
6019             }
6020         }
6021       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6022                || TREE_CODE (constructor_type) == UNION_TYPE)
6023         {
6024           tree ctor_unfilled_bitpos, elt_bitpos;
6025
6026           /* If the current record is complete we are done.  */
6027           if (constructor_unfilled_fields == 0)
6028             break;
6029
6030           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6031           elt_bitpos = bit_position (elt->purpose);
6032           /* We can't compare fields here because there might be empty
6033              fields in between.  */
6034           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6035             {
6036               constructor_unfilled_fields = elt->purpose;
6037               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6038                                    elt->purpose, 0);
6039             }
6040           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6041             {
6042               /* Advance to the next smaller node.  */
6043               if (elt->left)
6044                 elt = elt->left;
6045               else
6046                 {
6047                   /* We have reached the smallest node bigger than the
6048                      current unfilled field.  Fill the space first.  */
6049                   next = elt->purpose;
6050                   break;
6051                 }
6052             }
6053           else
6054             {
6055               /* Advance to the next bigger node.  */
6056               if (elt->right)
6057                 elt = elt->right;
6058               else
6059                 {
6060                   /* We have reached the biggest node in a subtree.  Find
6061                      the parent of it, which is the next bigger node.  */
6062                   while (elt->parent && elt->parent->right == elt)
6063                     elt = elt->parent;
6064                   elt = elt->parent;
6065                   if (elt
6066                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6067                                            bit_position (elt->purpose))))
6068                     {
6069                       next = elt->purpose;
6070                       break;
6071                     }
6072                 }
6073             }
6074         }
6075     }
6076
6077   /* Ordinarily return, but not if we want to output all
6078      and there are elements left.  */
6079   if (!(all && next != 0))
6080     return;
6081
6082   /* If it's not incremental, just skip over the gap, so that after
6083      jumping to retry we will output the next successive element.  */
6084   if (TREE_CODE (constructor_type) == RECORD_TYPE
6085       || TREE_CODE (constructor_type) == UNION_TYPE)
6086     constructor_unfilled_fields = next;
6087   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6088     constructor_unfilled_index = next;
6089
6090   /* ELT now points to the node in the pending tree with the next
6091      initializer to output.  */
6092   goto retry;
6093 }
6094 \f
6095 /* Add one non-braced element to the current constructor level.
6096    This adjusts the current position within the constructor's type.
6097    This may also start or terminate implicit levels
6098    to handle a partly-braced initializer.
6099
6100    Once this has found the correct level for the new element,
6101    it calls output_init_element.  */
6102
6103 void
6104 process_init_element (struct c_expr value)
6105 {
6106   tree orig_value = value.value;
6107   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6108   bool strict_string = value.original_code == STRING_CST;
6109
6110   designator_depth = 0;
6111   designator_errorneous = 0;
6112
6113   /* Handle superfluous braces around string cst as in
6114      char x[] = {"foo"}; */
6115   if (string_flag
6116       && constructor_type
6117       && TREE_CODE (constructor_type) == ARRAY_TYPE
6118       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6119       && integer_zerop (constructor_unfilled_index))
6120     {
6121       if (constructor_stack->replacement_value.value)
6122         error_init ("excess elements in char array initializer");
6123       constructor_stack->replacement_value = value;
6124       return;
6125     }
6126
6127   if (constructor_stack->replacement_value.value != 0)
6128     {
6129       error_init ("excess elements in struct initializer");
6130       return;
6131     }
6132
6133   /* Ignore elements of a brace group if it is entirely superfluous
6134      and has already been diagnosed.  */
6135   if (constructor_type == 0)
6136     return;
6137
6138   /* If we've exhausted any levels that didn't have braces,
6139      pop them now.  */
6140   while (constructor_stack->implicit)
6141     {
6142       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6143            || TREE_CODE (constructor_type) == UNION_TYPE)
6144           && constructor_fields == 0)
6145         process_init_element (pop_init_level (1));
6146       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6147                && (constructor_max_index == 0
6148                    || tree_int_cst_lt (constructor_max_index,
6149                                        constructor_index)))
6150         process_init_element (pop_init_level (1));
6151       else
6152         break;
6153     }
6154
6155   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6156   if (constructor_range_stack)
6157     {
6158       /* If value is a compound literal and we'll be just using its
6159          content, don't put it into a SAVE_EXPR.  */
6160       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6161           || !require_constant_value
6162           || flag_isoc99)
6163         value.value = save_expr (value.value);
6164     }
6165
6166   while (1)
6167     {
6168       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6169         {
6170           tree fieldtype;
6171           enum tree_code fieldcode;
6172
6173           if (constructor_fields == 0)
6174             {
6175               pedwarn_init ("excess elements in struct initializer");
6176               break;
6177             }
6178
6179           fieldtype = TREE_TYPE (constructor_fields);
6180           if (fieldtype != error_mark_node)
6181             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6182           fieldcode = TREE_CODE (fieldtype);
6183
6184           /* Error for non-static initialization of a flexible array member.  */
6185           if (fieldcode == ARRAY_TYPE
6186               && !require_constant_value
6187               && TYPE_SIZE (fieldtype) == NULL_TREE
6188               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6189             {
6190               error_init ("non-static initialization of a flexible array member");
6191               break;
6192             }
6193
6194           /* Accept a string constant to initialize a subarray.  */
6195           if (value.value != 0
6196               && fieldcode == ARRAY_TYPE
6197               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6198               && string_flag)
6199             value.value = orig_value;
6200           /* Otherwise, if we have come to a subaggregate,
6201              and we don't have an element of its type, push into it.  */
6202           else if (value.value != 0
6203                    && value.value != error_mark_node
6204                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6205                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6206                        || fieldcode == UNION_TYPE))
6207             {
6208               push_init_level (1);
6209               continue;
6210             }
6211
6212           if (value.value)
6213             {
6214               push_member_name (constructor_fields);
6215               output_init_element (value.value, strict_string,
6216                                    fieldtype, constructor_fields, 1);
6217               RESTORE_SPELLING_DEPTH (constructor_depth);
6218             }
6219           else
6220             /* Do the bookkeeping for an element that was
6221                directly output as a constructor.  */
6222             {
6223               /* For a record, keep track of end position of last field.  */
6224               if (DECL_SIZE (constructor_fields))
6225                 constructor_bit_index
6226                   = size_binop (PLUS_EXPR,
6227                                 bit_position (constructor_fields),
6228                                 DECL_SIZE (constructor_fields));
6229
6230               /* If the current field was the first one not yet written out,
6231                  it isn't now, so update.  */
6232               if (constructor_unfilled_fields == constructor_fields)
6233                 {
6234                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6235                   /* Skip any nameless bit fields.  */
6236                   while (constructor_unfilled_fields != 0
6237                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6238                          && DECL_NAME (constructor_unfilled_fields) == 0)
6239                     constructor_unfilled_fields =
6240                       TREE_CHAIN (constructor_unfilled_fields);
6241                 }
6242             }
6243
6244           constructor_fields = TREE_CHAIN (constructor_fields);
6245           /* Skip any nameless bit fields at the beginning.  */
6246           while (constructor_fields != 0
6247                  && DECL_C_BIT_FIELD (constructor_fields)
6248                  && DECL_NAME (constructor_fields) == 0)
6249             constructor_fields = TREE_CHAIN (constructor_fields);
6250         }
6251       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6252         {
6253           tree fieldtype;
6254           enum tree_code fieldcode;
6255
6256           if (constructor_fields == 0)
6257             {
6258               pedwarn_init ("excess elements in union initializer");
6259               break;
6260             }
6261
6262           fieldtype = TREE_TYPE (constructor_fields);
6263           if (fieldtype != error_mark_node)
6264             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6265           fieldcode = TREE_CODE (fieldtype);
6266
6267           /* Warn that traditional C rejects initialization of unions.
6268              We skip the warning if the value is zero.  This is done
6269              under the assumption that the zero initializer in user
6270              code appears conditioned on e.g. __STDC__ to avoid
6271              "missing initializer" warnings and relies on default
6272              initialization to zero in the traditional C case.
6273              We also skip the warning if the initializer is designated,
6274              again on the assumption that this must be conditional on
6275              __STDC__ anyway (and we've already complained about the
6276              member-designator already).  */
6277           if (!in_system_header && !constructor_designated
6278               && !(value.value && (integer_zerop (value.value)
6279                                    || real_zerop (value.value))))
6280             warning (OPT_Wtraditional, "traditional C rejects initialization "
6281                      "of unions");
6282
6283           /* Accept a string constant to initialize a subarray.  */
6284           if (value.value != 0
6285               && fieldcode == ARRAY_TYPE
6286               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6287               && string_flag)
6288             value.value = orig_value;
6289           /* Otherwise, if we have come to a subaggregate,
6290              and we don't have an element of its type, push into it.  */
6291           else if (value.value != 0
6292                    && value.value != error_mark_node
6293                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6294                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6295                        || fieldcode == UNION_TYPE))
6296             {
6297               push_init_level (1);
6298               continue;
6299             }
6300
6301           if (value.value)
6302             {
6303               push_member_name (constructor_fields);
6304               output_init_element (value.value, strict_string,
6305                                    fieldtype, constructor_fields, 1);
6306               RESTORE_SPELLING_DEPTH (constructor_depth);
6307             }
6308           else
6309             /* Do the bookkeeping for an element that was
6310                directly output as a constructor.  */
6311             {
6312               constructor_bit_index = DECL_SIZE (constructor_fields);
6313               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6314             }
6315
6316           constructor_fields = 0;
6317         }
6318       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6319         {
6320           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6321           enum tree_code eltcode = TREE_CODE (elttype);
6322
6323           /* Accept a string constant to initialize a subarray.  */
6324           if (value.value != 0
6325               && eltcode == ARRAY_TYPE
6326               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6327               && string_flag)
6328             value.value = orig_value;
6329           /* Otherwise, if we have come to a subaggregate,
6330              and we don't have an element of its type, push into it.  */
6331           else if (value.value != 0
6332                    && value.value != error_mark_node
6333                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6334                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6335                        || eltcode == UNION_TYPE))
6336             {
6337               push_init_level (1);
6338               continue;
6339             }
6340
6341           if (constructor_max_index != 0
6342               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6343                   || integer_all_onesp (constructor_max_index)))
6344             {
6345               pedwarn_init ("excess elements in array initializer");
6346               break;
6347             }
6348
6349           /* Now output the actual element.  */
6350           if (value.value)
6351             {
6352               push_array_bounds (tree_low_cst (constructor_index, 0));
6353               output_init_element (value.value, strict_string,
6354                                    elttype, constructor_index, 1);
6355               RESTORE_SPELLING_DEPTH (constructor_depth);
6356             }
6357
6358           constructor_index
6359             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6360
6361           if (!value.value)
6362             /* If we are doing the bookkeeping for an element that was
6363                directly output as a constructor, we must update
6364                constructor_unfilled_index.  */
6365             constructor_unfilled_index = constructor_index;
6366         }
6367       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6368         {
6369           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6370
6371          /* Do a basic check of initializer size.  Note that vectors
6372             always have a fixed size derived from their type.  */
6373           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6374             {
6375               pedwarn_init ("excess elements in vector initializer");
6376               break;
6377             }
6378
6379           /* Now output the actual element.  */
6380           if (value.value)
6381             output_init_element (value.value, strict_string,
6382                                  elttype, constructor_index, 1);
6383
6384           constructor_index
6385             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6386
6387           if (!value.value)
6388             /* If we are doing the bookkeeping for an element that was
6389                directly output as a constructor, we must update
6390                constructor_unfilled_index.  */
6391             constructor_unfilled_index = constructor_index;
6392         }
6393
6394       /* Handle the sole element allowed in a braced initializer
6395          for a scalar variable.  */
6396       else if (constructor_type != error_mark_node
6397                && constructor_fields == 0)
6398         {
6399           pedwarn_init ("excess elements in scalar initializer");
6400           break;
6401         }
6402       else
6403         {
6404           if (value.value)
6405             output_init_element (value.value, strict_string,
6406                                  constructor_type, NULL_TREE, 1);
6407           constructor_fields = 0;
6408         }
6409
6410       /* Handle range initializers either at this level or anywhere higher
6411          in the designator stack.  */
6412       if (constructor_range_stack)
6413         {
6414           struct constructor_range_stack *p, *range_stack;
6415           int finish = 0;
6416
6417           range_stack = constructor_range_stack;
6418           constructor_range_stack = 0;
6419           while (constructor_stack != range_stack->stack)
6420             {
6421               gcc_assert (constructor_stack->implicit);
6422               process_init_element (pop_init_level (1));
6423             }
6424           for (p = range_stack;
6425                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6426                p = p->prev)
6427             {
6428               gcc_assert (constructor_stack->implicit);
6429               process_init_element (pop_init_level (1));
6430             }
6431
6432           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6433           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6434             finish = 1;
6435
6436           while (1)
6437             {
6438               constructor_index = p->index;
6439               constructor_fields = p->fields;
6440               if (finish && p->range_end && p->index == p->range_start)
6441                 {
6442                   finish = 0;
6443                   p->prev = 0;
6444                 }
6445               p = p->next;
6446               if (!p)
6447                 break;
6448               push_init_level (2);
6449               p->stack = constructor_stack;
6450               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6451                 p->index = p->range_start;
6452             }
6453
6454           if (!finish)
6455             constructor_range_stack = range_stack;
6456           continue;
6457         }
6458
6459       break;
6460     }
6461
6462   constructor_range_stack = 0;
6463 }
6464 \f
6465 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6466    (guaranteed to be 'volatile' or null) and ARGS (represented using
6467    an ASM_EXPR node).  */
6468 tree
6469 build_asm_stmt (tree cv_qualifier, tree args)
6470 {
6471   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6472     ASM_VOLATILE_P (args) = 1;
6473   return add_stmt (args);
6474 }
6475
6476 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6477    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6478    SIMPLE indicates whether there was anything at all after the
6479    string in the asm expression -- asm("blah") and asm("blah" : )
6480    are subtly different.  We use a ASM_EXPR node to represent this.  */
6481 tree
6482 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6483                 bool simple)
6484 {
6485   tree tail;
6486   tree args;
6487   int i;
6488   const char *constraint;
6489   const char **oconstraints;
6490   bool allows_mem, allows_reg, is_inout;
6491   int ninputs, noutputs;
6492
6493   ninputs = list_length (inputs);
6494   noutputs = list_length (outputs);
6495   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6496
6497   string = resolve_asm_operand_names (string, outputs, inputs);
6498
6499   /* Remove output conversions that change the type but not the mode.  */
6500   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6501     {
6502       tree output = TREE_VALUE (tail);
6503
6504       /* ??? Really, this should not be here.  Users should be using a
6505          proper lvalue, dammit.  But there's a long history of using casts
6506          in the output operands.  In cases like longlong.h, this becomes a
6507          primitive form of typechecking -- if the cast can be removed, then
6508          the output operand had a type of the proper width; otherwise we'll
6509          get an error.  Gross, but ...  */
6510       STRIP_NOPS (output);
6511
6512       if (!lvalue_or_else (output, lv_asm))
6513         output = error_mark_node;
6514
6515       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6516       oconstraints[i] = constraint;
6517
6518       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6519                                    &allows_mem, &allows_reg, &is_inout))
6520         {
6521           /* If the operand is going to end up in memory,
6522              mark it addressable.  */
6523           if (!allows_reg && !c_mark_addressable (output))
6524             output = error_mark_node;
6525         }
6526       else
6527         output = error_mark_node;
6528
6529       TREE_VALUE (tail) = output;
6530     }
6531
6532   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6533     {
6534       tree input;
6535
6536       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6537       input = TREE_VALUE (tail);
6538
6539       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6540                                   oconstraints, &allows_mem, &allows_reg))
6541         {
6542           /* If the operand is going to end up in memory,
6543              mark it addressable.  */
6544           if (!allows_reg && allows_mem)
6545             {
6546               /* Strip the nops as we allow this case.  FIXME, this really
6547                  should be rejected or made deprecated.  */
6548               STRIP_NOPS (input);
6549               if (!c_mark_addressable (input))
6550                 input = error_mark_node;
6551           }
6552         }
6553       else
6554         input = error_mark_node;
6555
6556       TREE_VALUE (tail) = input;
6557     }
6558
6559   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6560
6561   /* Simple asm statements are treated as volatile.  */
6562   if (simple)
6563     {
6564       ASM_VOLATILE_P (args) = 1;
6565       ASM_INPUT_P (args) = 1;
6566     }
6567
6568   return args;
6569 }
6570 \f
6571 /* Generate a goto statement to LABEL.  */
6572
6573 tree
6574 c_finish_goto_label (tree label)
6575 {
6576   tree decl = lookup_label (label);
6577   if (!decl)
6578     return NULL_TREE;
6579
6580   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6581     {
6582       error ("jump into statement expression");
6583       return NULL_TREE;
6584     }
6585
6586   if (C_DECL_UNJUMPABLE_VM (decl))
6587     {
6588       error ("jump into scope of identifier with variably modified type");
6589       return NULL_TREE;
6590     }
6591
6592   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6593     {
6594       /* No jump from outside this statement expression context, so
6595          record that there is a jump from within this context.  */
6596       struct c_label_list *nlist;
6597       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6598       nlist->next = label_context_stack_se->labels_used;
6599       nlist->label = decl;
6600       label_context_stack_se->labels_used = nlist;
6601     }
6602
6603   if (!C_DECL_UNDEFINABLE_VM (decl))
6604     {
6605       /* No jump from outside this context context of identifiers with
6606          variably modified type, so record that there is a jump from
6607          within this context.  */
6608       struct c_label_list *nlist;
6609       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6610       nlist->next = label_context_stack_vm->labels_used;
6611       nlist->label = decl;
6612       label_context_stack_vm->labels_used = nlist;
6613     }
6614
6615   TREE_USED (decl) = 1;
6616   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6617 }
6618
6619 /* Generate a computed goto statement to EXPR.  */
6620
6621 tree
6622 c_finish_goto_ptr (tree expr)
6623 {
6624   if (pedantic)
6625     pedwarn ("ISO C forbids %<goto *expr;%>");
6626   expr = convert (ptr_type_node, expr);
6627   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6628 }
6629
6630 /* Generate a C `return' statement.  RETVAL is the expression for what
6631    to return, or a null pointer for `return;' with no value.  */
6632
6633 tree
6634 c_finish_return (tree retval)
6635 {
6636   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6637
6638   if (TREE_THIS_VOLATILE (current_function_decl))
6639     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6640
6641   if (!retval)
6642     {
6643       current_function_returns_null = 1;
6644       if ((warn_return_type || flag_isoc99)
6645           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6646         pedwarn_c99 ("%<return%> with no value, in "
6647                      "function returning non-void");
6648     }
6649   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6650     {
6651       current_function_returns_null = 1;
6652       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6653         pedwarn ("%<return%> with a value, in function returning void");
6654     }
6655   else
6656     {
6657       tree t = convert_for_assignment (valtype, retval, ic_return,
6658                                        NULL_TREE, NULL_TREE, 0);
6659       tree res = DECL_RESULT (current_function_decl);
6660       tree inner;
6661
6662       current_function_returns_value = 1;
6663       if (t == error_mark_node)
6664         return NULL_TREE;
6665
6666       inner = t = convert (TREE_TYPE (res), t);
6667
6668       /* Strip any conversions, additions, and subtractions, and see if
6669          we are returning the address of a local variable.  Warn if so.  */
6670       while (1)
6671         {
6672           switch (TREE_CODE (inner))
6673             {
6674             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6675             case PLUS_EXPR:
6676               inner = TREE_OPERAND (inner, 0);
6677               continue;
6678
6679             case MINUS_EXPR:
6680               /* If the second operand of the MINUS_EXPR has a pointer
6681                  type (or is converted from it), this may be valid, so
6682                  don't give a warning.  */
6683               {
6684                 tree op1 = TREE_OPERAND (inner, 1);
6685
6686                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6687                        && (TREE_CODE (op1) == NOP_EXPR
6688                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6689                            || TREE_CODE (op1) == CONVERT_EXPR))
6690                   op1 = TREE_OPERAND (op1, 0);
6691
6692                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6693                   break;
6694
6695                 inner = TREE_OPERAND (inner, 0);
6696                 continue;
6697               }
6698
6699             case ADDR_EXPR:
6700               inner = TREE_OPERAND (inner, 0);
6701
6702               while (REFERENCE_CLASS_P (inner)
6703                      && TREE_CODE (inner) != INDIRECT_REF)
6704                 inner = TREE_OPERAND (inner, 0);
6705
6706               if (DECL_P (inner)
6707                   && !DECL_EXTERNAL (inner)
6708                   && !TREE_STATIC (inner)
6709                   && DECL_CONTEXT (inner) == current_function_decl)
6710                 warning (0, "function returns address of local variable");
6711               break;
6712
6713             default:
6714               break;
6715             }
6716
6717           break;
6718         }
6719
6720       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6721     }
6722
6723   return add_stmt (build_stmt (RETURN_EXPR, retval));
6724 }
6725 \f
6726 struct c_switch {
6727   /* The SWITCH_EXPR being built.  */
6728   tree switch_expr;
6729
6730   /* The original type of the testing expression, i.e. before the
6731      default conversion is applied.  */
6732   tree orig_type;
6733
6734   /* A splay-tree mapping the low element of a case range to the high
6735      element, or NULL_TREE if there is no high element.  Used to
6736      determine whether or not a new case label duplicates an old case
6737      label.  We need a tree, rather than simply a hash table, because
6738      of the GNU case range extension.  */
6739   splay_tree cases;
6740
6741   /* Number of nested statement expressions within this switch
6742      statement; if nonzero, case and default labels may not
6743      appear.  */
6744   unsigned int blocked_stmt_expr;
6745
6746   /* Scope of outermost declarations of identifiers with variably
6747      modified type within this switch statement; if nonzero, case and
6748      default labels may not appear.  */
6749   unsigned int blocked_vm;
6750
6751   /* The next node on the stack.  */
6752   struct c_switch *next;
6753 };
6754
6755 /* A stack of the currently active switch statements.  The innermost
6756    switch statement is on the top of the stack.  There is no need to
6757    mark the stack for garbage collection because it is only active
6758    during the processing of the body of a function, and we never
6759    collect at that point.  */
6760
6761 struct c_switch *c_switch_stack;
6762
6763 /* Start a C switch statement, testing expression EXP.  Return the new
6764    SWITCH_EXPR.  */
6765
6766 tree
6767 c_start_case (tree exp)
6768 {
6769   enum tree_code code;
6770   tree type, orig_type = error_mark_node;
6771   struct c_switch *cs;
6772
6773   if (exp != error_mark_node)
6774     {
6775       code = TREE_CODE (TREE_TYPE (exp));
6776       orig_type = TREE_TYPE (exp);
6777
6778       if (!INTEGRAL_TYPE_P (orig_type)
6779           && code != ERROR_MARK)
6780         {
6781           error ("switch quantity not an integer");
6782           exp = integer_zero_node;
6783           orig_type = error_mark_node;
6784         }
6785       else
6786         {
6787           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6788
6789           if (!in_system_header
6790               && (type == long_integer_type_node
6791                   || type == long_unsigned_type_node))
6792             warning (OPT_Wtraditional, "%<long%> switch expression not "
6793                      "converted to %<int%> in ISO C");
6794
6795           exp = default_conversion (exp);
6796           type = TREE_TYPE (exp);
6797         }
6798     }
6799
6800   /* Add this new SWITCH_EXPR to the stack.  */
6801   cs = XNEW (struct c_switch);
6802   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6803   cs->orig_type = orig_type;
6804   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6805   cs->blocked_stmt_expr = 0;
6806   cs->blocked_vm = 0;
6807   cs->next = c_switch_stack;
6808   c_switch_stack = cs;
6809
6810   return add_stmt (cs->switch_expr);
6811 }
6812
6813 /* Process a case label.  */
6814
6815 tree
6816 do_case (tree low_value, tree high_value)
6817 {
6818   tree label = NULL_TREE;
6819
6820   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
6821       && !c_switch_stack->blocked_vm)
6822     {
6823       label = c_add_case_label (c_switch_stack->cases,
6824                                 SWITCH_COND (c_switch_stack->switch_expr),
6825                                 c_switch_stack->orig_type,
6826                                 low_value, high_value);
6827       if (label == error_mark_node)
6828         label = NULL_TREE;
6829     }
6830   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
6831     {
6832       if (low_value)
6833         error ("case label in statement expression not containing "
6834                "enclosing switch statement");
6835       else
6836         error ("%<default%> label in statement expression not containing "
6837                "enclosing switch statement");
6838     }
6839   else if (c_switch_stack && c_switch_stack->blocked_vm)
6840     {
6841       if (low_value)
6842         error ("case label in scope of identifier with variably modified "
6843                "type not containing enclosing switch statement");
6844       else
6845         error ("%<default%> label in scope of identifier with variably "
6846                "modified type not containing enclosing switch statement");
6847     }
6848   else if (low_value)
6849     error ("case label not within a switch statement");
6850   else
6851     error ("%<default%> label not within a switch statement");
6852
6853   return label;
6854 }
6855
6856 /* Finish the switch statement.  */
6857
6858 void
6859 c_finish_case (tree body)
6860 {
6861   struct c_switch *cs = c_switch_stack;
6862   location_t switch_location;
6863
6864   SWITCH_BODY (cs->switch_expr) = body;
6865
6866   /* We must not be within a statement expression nested in the switch
6867      at this point; we might, however, be within the scope of an
6868      identifier with variably modified type nested in the switch.  */
6869   gcc_assert (!cs->blocked_stmt_expr);
6870
6871   /* Emit warnings as needed.  */
6872   if (EXPR_HAS_LOCATION (cs->switch_expr))
6873     switch_location = EXPR_LOCATION (cs->switch_expr);
6874   else
6875     switch_location = input_location;
6876   c_do_switch_warnings (cs->cases, switch_location,
6877                         TREE_TYPE (cs->switch_expr),
6878                         SWITCH_COND (cs->switch_expr));
6879
6880   /* Pop the stack.  */
6881   c_switch_stack = cs->next;
6882   splay_tree_delete (cs->cases);
6883   XDELETE (cs);
6884 }
6885 \f
6886 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6887    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6888    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6889    statement, and was not surrounded with parenthesis.  */
6890
6891 void
6892 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6893                   tree else_block, bool nested_if)
6894 {
6895   tree stmt;
6896
6897   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6898   if (warn_parentheses && nested_if && else_block == NULL)
6899     {
6900       tree inner_if = then_block;
6901
6902       /* We know from the grammar productions that there is an IF nested
6903          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6904          it might not be exactly THEN_BLOCK, but should be the last
6905          non-container statement within.  */
6906       while (1)
6907         switch (TREE_CODE (inner_if))
6908           {
6909           case COND_EXPR:
6910             goto found;
6911           case BIND_EXPR:
6912             inner_if = BIND_EXPR_BODY (inner_if);
6913             break;
6914           case STATEMENT_LIST:
6915             inner_if = expr_last (then_block);
6916             break;
6917           case TRY_FINALLY_EXPR:
6918           case TRY_CATCH_EXPR:
6919             inner_if = TREE_OPERAND (inner_if, 0);
6920             break;
6921           default:
6922             gcc_unreachable ();
6923           }
6924     found:
6925
6926       if (COND_EXPR_ELSE (inner_if))
6927          warning (0, "%Hsuggest explicit braces to avoid ambiguous %<else%>",
6928                   &if_locus);
6929     }
6930
6931   /* Diagnose ";" via the special empty statement node that we create.  */
6932   if (extra_warnings)
6933     {
6934       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
6935         {
6936           if (!else_block)
6937             warning (0, "%Hempty body in an if-statement",
6938                      EXPR_LOCUS (then_block));
6939           then_block = alloc_stmt_list ();
6940         }
6941       if (else_block
6942           && TREE_CODE (else_block) == NOP_EXPR
6943           && !TREE_TYPE (else_block))
6944         {
6945           warning (0, "%Hempty body in an else-statement",
6946                    EXPR_LOCUS (else_block));
6947           else_block = alloc_stmt_list ();
6948         }
6949     }
6950
6951   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
6952   SET_EXPR_LOCATION (stmt, if_locus);
6953   add_stmt (stmt);
6954 }
6955
6956 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
6957    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
6958    is false for DO loops.  INCR is the FOR increment expression.  BODY is
6959    the statement controlled by the loop.  BLAB is the break label.  CLAB is
6960    the continue label.  Everything is allowed to be NULL.  */
6961
6962 void
6963 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
6964                tree blab, tree clab, bool cond_is_first)
6965 {
6966   tree entry = NULL, exit = NULL, t;
6967
6968   /* If the condition is zero don't generate a loop construct.  */
6969   if (cond && integer_zerop (cond))
6970     {
6971       if (cond_is_first)
6972         {
6973           t = build_and_jump (&blab);
6974           SET_EXPR_LOCATION (t, start_locus);
6975           add_stmt (t);
6976         }
6977     }
6978   else
6979     {
6980       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6981
6982       /* If we have an exit condition, then we build an IF with gotos either
6983          out of the loop, or to the top of it.  If there's no exit condition,
6984          then we just build a jump back to the top.  */
6985       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
6986
6987       if (cond && !integer_nonzerop (cond))
6988         {
6989           /* Canonicalize the loop condition to the end.  This means
6990              generating a branch to the loop condition.  Reuse the
6991              continue label, if possible.  */
6992           if (cond_is_first)
6993             {
6994               if (incr || !clab)
6995                 {
6996                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6997                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
6998                 }
6999               else
7000                 t = build1 (GOTO_EXPR, void_type_node, clab);
7001               SET_EXPR_LOCATION (t, start_locus);
7002               add_stmt (t);
7003             }
7004
7005           t = build_and_jump (&blab);
7006           exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
7007           exit = fold (exit);
7008           if (cond_is_first)
7009             SET_EXPR_LOCATION (exit, start_locus);
7010           else
7011             SET_EXPR_LOCATION (exit, input_location);
7012         }
7013
7014       add_stmt (top);
7015     }
7016
7017   if (body)
7018     add_stmt (body);
7019   if (clab)
7020     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7021   if (incr)
7022     add_stmt (incr);
7023   if (entry)
7024     add_stmt (entry);
7025   if (exit)
7026     add_stmt (exit);
7027   if (blab)
7028     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7029 }
7030
7031 tree
7032 c_finish_bc_stmt (tree *label_p, bool is_break)
7033 {
7034   bool skip;
7035   tree label = *label_p;
7036
7037   /* In switch statements break is sometimes stylistically used after
7038      a return statement.  This can lead to spurious warnings about
7039      control reaching the end of a non-void function when it is
7040      inlined.  Note that we are calling block_may_fallthru with
7041      language specific tree nodes; this works because
7042      block_may_fallthru returns true when given something it does not
7043      understand.  */
7044   skip = !block_may_fallthru (cur_stmt_list);
7045
7046   if (!label)
7047     {
7048       if (!skip)
7049         *label_p = label = create_artificial_label ();
7050     }
7051   else if (TREE_CODE (label) != LABEL_DECL)
7052     {
7053       if (is_break)
7054         error ("break statement not within loop or switch");
7055       else
7056         error ("continue statement not within a loop");
7057       return NULL_TREE;
7058     }
7059
7060   if (skip)
7061     return NULL_TREE;
7062
7063   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7064 }
7065
7066 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7067
7068 static void
7069 emit_side_effect_warnings (tree expr)
7070 {
7071   if (expr == error_mark_node)
7072     ;
7073   else if (!TREE_SIDE_EFFECTS (expr))
7074     {
7075       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7076         warning (0, "%Hstatement with no effect",
7077                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7078     }
7079   else if (warn_unused_value)
7080     warn_if_unused_value (expr, input_location);
7081 }
7082
7083 /* Process an expression as if it were a complete statement.  Emit
7084    diagnostics, but do not call ADD_STMT.  */
7085
7086 tree
7087 c_process_expr_stmt (tree expr)
7088 {
7089   if (!expr)
7090     return NULL_TREE;
7091
7092   if (warn_sequence_point)
7093     verify_sequence_points (expr);
7094
7095   if (TREE_TYPE (expr) != error_mark_node
7096       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7097       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7098     error ("expression statement has incomplete type");
7099
7100   /* If we're not processing a statement expression, warn about unused values.
7101      Warnings for statement expressions will be emitted later, once we figure
7102      out which is the result.  */
7103   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7104       && (extra_warnings || warn_unused_value))
7105     emit_side_effect_warnings (expr);
7106
7107   /* If the expression is not of a type to which we cannot assign a line
7108      number, wrap the thing in a no-op NOP_EXPR.  */
7109   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7110     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7111
7112   if (EXPR_P (expr))
7113     SET_EXPR_LOCATION (expr, input_location);
7114
7115   return expr;
7116 }
7117
7118 /* Emit an expression as a statement.  */
7119
7120 tree
7121 c_finish_expr_stmt (tree expr)
7122 {
7123   if (expr)
7124     return add_stmt (c_process_expr_stmt (expr));
7125   else
7126     return NULL;
7127 }
7128
7129 /* Do the opposite and emit a statement as an expression.  To begin,
7130    create a new binding level and return it.  */
7131
7132 tree
7133 c_begin_stmt_expr (void)
7134 {
7135   tree ret;
7136   struct c_label_context_se *nstack;
7137   struct c_label_list *glist;
7138
7139   /* We must force a BLOCK for this level so that, if it is not expanded
7140      later, there is a way to turn off the entire subtree of blocks that
7141      are contained in it.  */
7142   keep_next_level ();
7143   ret = c_begin_compound_stmt (true);
7144   if (c_switch_stack)
7145     {
7146       c_switch_stack->blocked_stmt_expr++;
7147       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7148     }
7149   for (glist = label_context_stack_se->labels_used;
7150        glist != NULL;
7151        glist = glist->next)
7152     {
7153       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7154     }
7155   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7156   nstack->labels_def = NULL;
7157   nstack->labels_used = NULL;
7158   nstack->next = label_context_stack_se;
7159   label_context_stack_se = nstack;
7160
7161   /* Mark the current statement list as belonging to a statement list.  */
7162   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7163
7164   return ret;
7165 }
7166
7167 tree
7168 c_finish_stmt_expr (tree body)
7169 {
7170   tree last, type, tmp, val;
7171   tree *last_p;
7172   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7173
7174   body = c_end_compound_stmt (body, true);
7175   if (c_switch_stack)
7176     {
7177       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7178       c_switch_stack->blocked_stmt_expr--;
7179     }
7180   /* It is no longer possible to jump to labels defined within this
7181      statement expression.  */
7182   for (dlist = label_context_stack_se->labels_def;
7183        dlist != NULL;
7184        dlist = dlist->next)
7185     {
7186       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7187     }
7188   /* It is again possible to define labels with a goto just outside
7189      this statement expression.  */
7190   for (glist = label_context_stack_se->next->labels_used;
7191        glist != NULL;
7192        glist = glist->next)
7193     {
7194       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7195       glist_prev = glist;
7196     }
7197   if (glist_prev != NULL)
7198     glist_prev->next = label_context_stack_se->labels_used;
7199   else
7200     label_context_stack_se->next->labels_used
7201       = label_context_stack_se->labels_used;
7202   label_context_stack_se = label_context_stack_se->next;
7203
7204   /* Locate the last statement in BODY.  See c_end_compound_stmt
7205      about always returning a BIND_EXPR.  */
7206   last_p = &BIND_EXPR_BODY (body);
7207   last = BIND_EXPR_BODY (body);
7208
7209  continue_searching:
7210   if (TREE_CODE (last) == STATEMENT_LIST)
7211     {
7212       tree_stmt_iterator i;
7213
7214       /* This can happen with degenerate cases like ({ }).  No value.  */
7215       if (!TREE_SIDE_EFFECTS (last))
7216         return body;
7217
7218       /* If we're supposed to generate side effects warnings, process
7219          all of the statements except the last.  */
7220       if (extra_warnings || warn_unused_value)
7221         {
7222           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7223             emit_side_effect_warnings (tsi_stmt (i));
7224         }
7225       else
7226         i = tsi_last (last);
7227       last_p = tsi_stmt_ptr (i);
7228       last = *last_p;
7229     }
7230
7231   /* If the end of the list is exception related, then the list was split
7232      by a call to push_cleanup.  Continue searching.  */
7233   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7234       || TREE_CODE (last) == TRY_CATCH_EXPR)
7235     {
7236       last_p = &TREE_OPERAND (last, 0);
7237       last = *last_p;
7238       goto continue_searching;
7239     }
7240
7241   /* In the case that the BIND_EXPR is not necessary, return the
7242      expression out from inside it.  */
7243   if (last == error_mark_node
7244       || (last == BIND_EXPR_BODY (body)
7245           && BIND_EXPR_VARS (body) == NULL))
7246     return last;
7247
7248   /* Extract the type of said expression.  */
7249   type = TREE_TYPE (last);
7250
7251   /* If we're not returning a value at all, then the BIND_EXPR that
7252      we already have is a fine expression to return.  */
7253   if (!type || VOID_TYPE_P (type))
7254     return body;
7255
7256   /* Now that we've located the expression containing the value, it seems
7257      silly to make voidify_wrapper_expr repeat the process.  Create a
7258      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7259   tmp = create_tmp_var_raw (type, NULL);
7260
7261   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7262      tree_expr_nonnegative_p giving up immediately.  */
7263   val = last;
7264   if (TREE_CODE (val) == NOP_EXPR
7265       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7266     val = TREE_OPERAND (val, 0);
7267
7268   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7269   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7270
7271   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7272 }
7273
7274 /* Begin the scope of an identifier of variably modified type, scope
7275    number SCOPE.  Jumping from outside this scope to inside it is not
7276    permitted.  */
7277
7278 void
7279 c_begin_vm_scope (unsigned int scope)
7280 {
7281   struct c_label_context_vm *nstack;
7282   struct c_label_list *glist;
7283
7284   gcc_assert (scope > 0);
7285   if (c_switch_stack && !c_switch_stack->blocked_vm)
7286     c_switch_stack->blocked_vm = scope;
7287   for (glist = label_context_stack_vm->labels_used;
7288        glist != NULL;
7289        glist = glist->next)
7290     {
7291       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7292     }
7293   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7294   nstack->labels_def = NULL;
7295   nstack->labels_used = NULL;
7296   nstack->scope = scope;
7297   nstack->next = label_context_stack_vm;
7298   label_context_stack_vm = nstack;
7299 }
7300
7301 /* End a scope which may contain identifiers of variably modified
7302    type, scope number SCOPE.  */
7303
7304 void
7305 c_end_vm_scope (unsigned int scope)
7306 {
7307   if (label_context_stack_vm == NULL)
7308     return;
7309   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7310     c_switch_stack->blocked_vm = 0;
7311   /* We may have a number of nested scopes of identifiers with
7312      variably modified type, all at this depth.  Pop each in turn.  */
7313   while (label_context_stack_vm->scope == scope)
7314     {
7315       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7316
7317       /* It is no longer possible to jump to labels defined within this
7318          scope.  */
7319       for (dlist = label_context_stack_vm->labels_def;
7320            dlist != NULL;
7321            dlist = dlist->next)
7322         {
7323           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7324         }
7325       /* It is again possible to define labels with a goto just outside
7326          this scope.  */
7327       for (glist = label_context_stack_vm->next->labels_used;
7328            glist != NULL;
7329            glist = glist->next)
7330         {
7331           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7332           glist_prev = glist;
7333         }
7334       if (glist_prev != NULL)
7335         glist_prev->next = label_context_stack_vm->labels_used;
7336       else
7337         label_context_stack_vm->next->labels_used
7338           = label_context_stack_vm->labels_used;
7339       label_context_stack_vm = label_context_stack_vm->next;
7340     }
7341 }
7342 \f
7343 /* Begin and end compound statements.  This is as simple as pushing
7344    and popping new statement lists from the tree.  */
7345
7346 tree
7347 c_begin_compound_stmt (bool do_scope)
7348 {
7349   tree stmt = push_stmt_list ();
7350   if (do_scope)
7351     push_scope ();
7352   return stmt;
7353 }
7354
7355 tree
7356 c_end_compound_stmt (tree stmt, bool do_scope)
7357 {
7358   tree block = NULL;
7359
7360   if (do_scope)
7361     {
7362       if (c_dialect_objc ())
7363         objc_clear_super_receiver ();
7364       block = pop_scope ();
7365     }
7366
7367   stmt = pop_stmt_list (stmt);
7368   stmt = c_build_bind_expr (block, stmt);
7369
7370   /* If this compound statement is nested immediately inside a statement
7371      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7372      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7373      STATEMENT_LISTs merge, and thus we can lose track of what statement
7374      was really last.  */
7375   if (cur_stmt_list
7376       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7377       && TREE_CODE (stmt) != BIND_EXPR)
7378     {
7379       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7380       TREE_SIDE_EFFECTS (stmt) = 1;
7381     }
7382
7383   return stmt;
7384 }
7385
7386 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7387    when the current scope is exited.  EH_ONLY is true when this is not
7388    meant to apply to normal control flow transfer.  */
7389
7390 void
7391 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7392 {
7393   enum tree_code code;
7394   tree stmt, list;
7395   bool stmt_expr;
7396
7397   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7398   stmt = build_stmt (code, NULL, cleanup);
7399   add_stmt (stmt);
7400   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7401   list = push_stmt_list ();
7402   TREE_OPERAND (stmt, 0) = list;
7403   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7404 }
7405 \f
7406 /* Build a binary-operation expression without default conversions.
7407    CODE is the kind of expression to build.
7408    This function differs from `build' in several ways:
7409    the data type of the result is computed and recorded in it,
7410    warnings are generated if arg data types are invalid,
7411    special handling for addition and subtraction of pointers is known,
7412    and some optimization is done (operations on narrow ints
7413    are done in the narrower type when that gives the same result).
7414    Constant folding is also done before the result is returned.
7415
7416    Note that the operands will never have enumeral types, or function
7417    or array types, because either they will have the default conversions
7418    performed or they have both just been converted to some other type in which
7419    the arithmetic is to be done.  */
7420
7421 tree
7422 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7423                  int convert_p)
7424 {
7425   tree type0, type1;
7426   enum tree_code code0, code1;
7427   tree op0, op1;
7428   const char *invalid_op_diag;
7429
7430   /* Expression code to give to the expression when it is built.
7431      Normally this is CODE, which is what the caller asked for,
7432      but in some special cases we change it.  */
7433   enum tree_code resultcode = code;
7434
7435   /* Data type in which the computation is to be performed.
7436      In the simplest cases this is the common type of the arguments.  */
7437   tree result_type = NULL;
7438
7439   /* Nonzero means operands have already been type-converted
7440      in whatever way is necessary.
7441      Zero means they need to be converted to RESULT_TYPE.  */
7442   int converted = 0;
7443
7444   /* Nonzero means create the expression with this type, rather than
7445      RESULT_TYPE.  */
7446   tree build_type = 0;
7447
7448   /* Nonzero means after finally constructing the expression
7449      convert it to this type.  */
7450   tree final_type = 0;
7451
7452   /* Nonzero if this is an operation like MIN or MAX which can
7453      safely be computed in short if both args are promoted shorts.
7454      Also implies COMMON.
7455      -1 indicates a bitwise operation; this makes a difference
7456      in the exact conditions for when it is safe to do the operation
7457      in a narrower mode.  */
7458   int shorten = 0;
7459
7460   /* Nonzero if this is a comparison operation;
7461      if both args are promoted shorts, compare the original shorts.
7462      Also implies COMMON.  */
7463   int short_compare = 0;
7464
7465   /* Nonzero if this is a right-shift operation, which can be computed on the
7466      original short and then promoted if the operand is a promoted short.  */
7467   int short_shift = 0;
7468
7469   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7470   int common = 0;
7471
7472   /* True means types are compatible as far as ObjC is concerned.  */
7473   bool objc_ok;
7474
7475   if (convert_p)
7476     {
7477       op0 = default_conversion (orig_op0);
7478       op1 = default_conversion (orig_op1);
7479     }
7480   else
7481     {
7482       op0 = orig_op0;
7483       op1 = orig_op1;
7484     }
7485
7486   type0 = TREE_TYPE (op0);
7487   type1 = TREE_TYPE (op1);
7488
7489   /* The expression codes of the data types of the arguments tell us
7490      whether the arguments are integers, floating, pointers, etc.  */
7491   code0 = TREE_CODE (type0);
7492   code1 = TREE_CODE (type1);
7493
7494   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7495   STRIP_TYPE_NOPS (op0);
7496   STRIP_TYPE_NOPS (op1);
7497
7498   /* If an error was already reported for one of the arguments,
7499      avoid reporting another error.  */
7500
7501   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7502     return error_mark_node;
7503
7504   if ((invalid_op_diag
7505        = targetm.invalid_binary_op (code, type0, type1)))
7506     {
7507       error (invalid_op_diag);
7508       return error_mark_node;
7509     }
7510
7511   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7512
7513   switch (code)
7514     {
7515     case PLUS_EXPR:
7516       /* Handle the pointer + int case.  */
7517       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7518         return pointer_int_sum (PLUS_EXPR, op0, op1);
7519       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7520         return pointer_int_sum (PLUS_EXPR, op1, op0);
7521       else
7522         common = 1;
7523       break;
7524
7525     case MINUS_EXPR:
7526       /* Subtraction of two similar pointers.
7527          We must subtract them as integers, then divide by object size.  */
7528       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7529           && comp_target_types (type0, type1))
7530         return pointer_diff (op0, op1);
7531       /* Handle pointer minus int.  Just like pointer plus int.  */
7532       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7533         return pointer_int_sum (MINUS_EXPR, op0, op1);
7534       else
7535         common = 1;
7536       break;
7537
7538     case MULT_EXPR:
7539       common = 1;
7540       break;
7541
7542     case TRUNC_DIV_EXPR:
7543     case CEIL_DIV_EXPR:
7544     case FLOOR_DIV_EXPR:
7545     case ROUND_DIV_EXPR:
7546     case EXACT_DIV_EXPR:
7547       /* Floating point division by zero is a legitimate way to obtain
7548          infinities and NaNs.  */
7549       if (skip_evaluation == 0 && integer_zerop (op1))
7550         warning (OPT_Wdiv_by_zero, "division by zero");
7551
7552       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7553            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7554           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7555               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7556         {
7557           enum tree_code tcode0 = code0, tcode1 = code1;
7558
7559           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7560             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7561           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7562             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7563
7564           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7565             resultcode = RDIV_EXPR;
7566           else
7567             /* Although it would be tempting to shorten always here, that
7568                loses on some targets, since the modulo instruction is
7569                undefined if the quotient can't be represented in the
7570                computation mode.  We shorten only if unsigned or if
7571                dividing by something we know != -1.  */
7572             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7573                        || (TREE_CODE (op1) == INTEGER_CST
7574                            && !integer_all_onesp (op1)));
7575           common = 1;
7576         }
7577       break;
7578
7579     case BIT_AND_EXPR:
7580     case BIT_IOR_EXPR:
7581     case BIT_XOR_EXPR:
7582       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7583         shorten = -1;
7584       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7585         common = 1;
7586       break;
7587
7588     case TRUNC_MOD_EXPR:
7589     case FLOOR_MOD_EXPR:
7590       if (skip_evaluation == 0 && integer_zerop (op1))
7591         warning (OPT_Wdiv_by_zero, "division by zero");
7592
7593       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7594         {
7595           /* Although it would be tempting to shorten always here, that loses
7596              on some targets, since the modulo instruction is undefined if the
7597              quotient can't be represented in the computation mode.  We shorten
7598              only if unsigned or if dividing by something we know != -1.  */
7599           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7600                      || (TREE_CODE (op1) == INTEGER_CST
7601                          && !integer_all_onesp (op1)));
7602           common = 1;
7603         }
7604       break;
7605
7606     case TRUTH_ANDIF_EXPR:
7607     case TRUTH_ORIF_EXPR:
7608     case TRUTH_AND_EXPR:
7609     case TRUTH_OR_EXPR:
7610     case TRUTH_XOR_EXPR:
7611       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7612            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7613           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7614               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7615         {
7616           /* Result of these operations is always an int,
7617              but that does not mean the operands should be
7618              converted to ints!  */
7619           result_type = integer_type_node;
7620           op0 = c_common_truthvalue_conversion (op0);
7621           op1 = c_common_truthvalue_conversion (op1);
7622           converted = 1;
7623         }
7624       break;
7625
7626       /* Shift operations: result has same type as first operand;
7627          always convert second operand to int.
7628          Also set SHORT_SHIFT if shifting rightward.  */
7629
7630     case RSHIFT_EXPR:
7631       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7632         {
7633           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7634             {
7635               if (tree_int_cst_sgn (op1) < 0)
7636                 warning (0, "right shift count is negative");
7637               else
7638                 {
7639                   if (!integer_zerop (op1))
7640                     short_shift = 1;
7641
7642                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7643                     warning (0, "right shift count >= width of type");
7644                 }
7645             }
7646
7647           /* Use the type of the value to be shifted.  */
7648           result_type = type0;
7649           /* Convert the shift-count to an integer, regardless of size
7650              of value being shifted.  */
7651           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7652             op1 = convert (integer_type_node, op1);
7653           /* Avoid converting op1 to result_type later.  */
7654           converted = 1;
7655         }
7656       break;
7657
7658     case LSHIFT_EXPR:
7659       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7660         {
7661           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7662             {
7663               if (tree_int_cst_sgn (op1) < 0)
7664                 warning (0, "left shift count is negative");
7665
7666               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7667                 warning (0, "left shift count >= width of type");
7668             }
7669
7670           /* Use the type of the value to be shifted.  */
7671           result_type = type0;
7672           /* Convert the shift-count to an integer, regardless of size
7673              of value being shifted.  */
7674           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7675             op1 = convert (integer_type_node, op1);
7676           /* Avoid converting op1 to result_type later.  */
7677           converted = 1;
7678         }
7679       break;
7680
7681     case EQ_EXPR:
7682     case NE_EXPR:
7683       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7684         warning (OPT_Wfloat_equal,
7685                  "comparing floating point with == or != is unsafe");
7686       /* Result of comparison is always int,
7687          but don't convert the args to int!  */
7688       build_type = integer_type_node;
7689       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7690            || code0 == COMPLEX_TYPE)
7691           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7692               || code1 == COMPLEX_TYPE))
7693         short_compare = 1;
7694       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7695         {
7696           tree tt0 = TREE_TYPE (type0);
7697           tree tt1 = TREE_TYPE (type1);
7698           /* Anything compares with void *.  void * compares with anything.
7699              Otherwise, the targets must be compatible
7700              and both must be object or both incomplete.  */
7701           if (comp_target_types (type0, type1))
7702             result_type = common_pointer_type (type0, type1);
7703           else if (VOID_TYPE_P (tt0))
7704             {
7705               /* op0 != orig_op0 detects the case of something
7706                  whose value is 0 but which isn't a valid null ptr const.  */
7707               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7708                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7709                 pedwarn ("ISO C forbids comparison of %<void *%>"
7710                          " with function pointer");
7711             }
7712           else if (VOID_TYPE_P (tt1))
7713             {
7714               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7715                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7716                 pedwarn ("ISO C forbids comparison of %<void *%>"
7717                          " with function pointer");
7718             }
7719           else
7720             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7721             if (!objc_ok)
7722               pedwarn ("comparison of distinct pointer types lacks a cast");
7723
7724           if (result_type == NULL_TREE)
7725             result_type = ptr_type_node;
7726         }
7727       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7728                && integer_zerop (op1))
7729         result_type = type0;
7730       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7731                && integer_zerop (op0))
7732         result_type = type1;
7733       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7734         {
7735           result_type = type0;
7736           pedwarn ("comparison between pointer and integer");
7737         }
7738       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7739         {
7740           result_type = type1;
7741           pedwarn ("comparison between pointer and integer");
7742         }
7743       break;
7744
7745     case LE_EXPR:
7746     case GE_EXPR:
7747     case LT_EXPR:
7748     case GT_EXPR:
7749       build_type = integer_type_node;
7750       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7751           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7752         short_compare = 1;
7753       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7754         {
7755           if (comp_target_types (type0, type1))
7756             {
7757               result_type = common_pointer_type (type0, type1);
7758               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7759                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7760                 pedwarn ("comparison of complete and incomplete pointers");
7761               else if (pedantic
7762                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7763                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7764             }
7765           else
7766             {
7767               result_type = ptr_type_node;
7768               pedwarn ("comparison of distinct pointer types lacks a cast");
7769             }
7770         }
7771       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7772                && integer_zerop (op1))
7773         {
7774           result_type = type0;
7775           if (pedantic || extra_warnings)
7776             pedwarn ("ordered comparison of pointer with integer zero");
7777         }
7778       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7779                && integer_zerop (op0))
7780         {
7781           result_type = type1;
7782           if (pedantic)
7783             pedwarn ("ordered comparison of pointer with integer zero");
7784         }
7785       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7786         {
7787           result_type = type0;
7788           pedwarn ("comparison between pointer and integer");
7789         }
7790       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7791         {
7792           result_type = type1;
7793           pedwarn ("comparison between pointer and integer");
7794         }
7795       break;
7796
7797     default:
7798       gcc_unreachable ();
7799     }
7800
7801   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7802     return error_mark_node;
7803
7804   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
7805       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
7806           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
7807                                                     TREE_TYPE (type1))))
7808     {
7809       binary_op_error (code);
7810       return error_mark_node;
7811     }
7812
7813   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7814        || code0 == VECTOR_TYPE)
7815       &&
7816       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7817        || code1 == VECTOR_TYPE))
7818     {
7819       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7820
7821       if (shorten || common || short_compare)
7822         result_type = c_common_type (type0, type1);
7823
7824       /* For certain operations (which identify themselves by shorten != 0)
7825          if both args were extended from the same smaller type,
7826          do the arithmetic in that type and then extend.
7827
7828          shorten !=0 and !=1 indicates a bitwise operation.
7829          For them, this optimization is safe only if
7830          both args are zero-extended or both are sign-extended.
7831          Otherwise, we might change the result.
7832          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7833          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7834
7835       if (shorten && none_complex)
7836         {
7837           int unsigned0, unsigned1;
7838           tree arg0 = get_narrower (op0, &unsigned0);
7839           tree arg1 = get_narrower (op1, &unsigned1);
7840           /* UNS is 1 if the operation to be done is an unsigned one.  */
7841           int uns = TYPE_UNSIGNED (result_type);
7842           tree type;
7843
7844           final_type = result_type;
7845
7846           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7847              but it *requires* conversion to FINAL_TYPE.  */
7848
7849           if ((TYPE_PRECISION (TREE_TYPE (op0))
7850                == TYPE_PRECISION (TREE_TYPE (arg0)))
7851               && TREE_TYPE (op0) != final_type)
7852             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7853           if ((TYPE_PRECISION (TREE_TYPE (op1))
7854                == TYPE_PRECISION (TREE_TYPE (arg1)))
7855               && TREE_TYPE (op1) != final_type)
7856             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7857
7858           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7859
7860           /* For bitwise operations, signedness of nominal type
7861              does not matter.  Consider only how operands were extended.  */
7862           if (shorten == -1)
7863             uns = unsigned0;
7864
7865           /* Note that in all three cases below we refrain from optimizing
7866              an unsigned operation on sign-extended args.
7867              That would not be valid.  */
7868
7869           /* Both args variable: if both extended in same way
7870              from same width, do it in that width.
7871              Do it unsigned if args were zero-extended.  */
7872           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7873                < TYPE_PRECISION (result_type))
7874               && (TYPE_PRECISION (TREE_TYPE (arg1))
7875                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7876               && unsigned0 == unsigned1
7877               && (unsigned0 || !uns))
7878             result_type
7879               = c_common_signed_or_unsigned_type
7880               (unsigned0, c_common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7881           else if (TREE_CODE (arg0) == INTEGER_CST
7882                    && (unsigned1 || !uns)
7883                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7884                        < TYPE_PRECISION (result_type))
7885                    && (type
7886                        = c_common_signed_or_unsigned_type (unsigned1,
7887                                                            TREE_TYPE (arg1)),
7888                        int_fits_type_p (arg0, type)))
7889             result_type = type;
7890           else if (TREE_CODE (arg1) == INTEGER_CST
7891                    && (unsigned0 || !uns)
7892                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7893                        < TYPE_PRECISION (result_type))
7894                    && (type
7895                        = c_common_signed_or_unsigned_type (unsigned0,
7896                                                            TREE_TYPE (arg0)),
7897                        int_fits_type_p (arg1, type)))
7898             result_type = type;
7899         }
7900
7901       /* Shifts can be shortened if shifting right.  */
7902
7903       if (short_shift)
7904         {
7905           int unsigned_arg;
7906           tree arg0 = get_narrower (op0, &unsigned_arg);
7907
7908           final_type = result_type;
7909
7910           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7911             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7912
7913           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7914               /* We can shorten only if the shift count is less than the
7915                  number of bits in the smaller type size.  */
7916               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7917               /* We cannot drop an unsigned shift after sign-extension.  */
7918               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7919             {
7920               /* Do an unsigned shift if the operand was zero-extended.  */
7921               result_type
7922                 = c_common_signed_or_unsigned_type (unsigned_arg,
7923                                                     TREE_TYPE (arg0));
7924               /* Convert value-to-be-shifted to that type.  */
7925               if (TREE_TYPE (op0) != result_type)
7926                 op0 = convert (result_type, op0);
7927               converted = 1;
7928             }
7929         }
7930
7931       /* Comparison operations are shortened too but differently.
7932          They identify themselves by setting short_compare = 1.  */
7933
7934       if (short_compare)
7935         {
7936           /* Don't write &op0, etc., because that would prevent op0
7937              from being kept in a register.
7938              Instead, make copies of the our local variables and
7939              pass the copies by reference, then copy them back afterward.  */
7940           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7941           enum tree_code xresultcode = resultcode;
7942           tree val
7943             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7944
7945           if (val != 0)
7946             return val;
7947
7948           op0 = xop0, op1 = xop1;
7949           converted = 1;
7950           resultcode = xresultcode;
7951
7952           if (warn_sign_compare && skip_evaluation == 0)
7953             {
7954               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
7955               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
7956               int unsignedp0, unsignedp1;
7957               tree primop0 = get_narrower (op0, &unsignedp0);
7958               tree primop1 = get_narrower (op1, &unsignedp1);
7959
7960               xop0 = orig_op0;
7961               xop1 = orig_op1;
7962               STRIP_TYPE_NOPS (xop0);
7963               STRIP_TYPE_NOPS (xop1);
7964
7965               /* Give warnings for comparisons between signed and unsigned
7966                  quantities that may fail.
7967
7968                  Do the checking based on the original operand trees, so that
7969                  casts will be considered, but default promotions won't be.
7970
7971                  Do not warn if the comparison is being done in a signed type,
7972                  since the signed type will only be chosen if it can represent
7973                  all the values of the unsigned type.  */
7974               if (!TYPE_UNSIGNED (result_type))
7975                 /* OK */;
7976               /* Do not warn if both operands are the same signedness.  */
7977               else if (op0_signed == op1_signed)
7978                 /* OK */;
7979               else
7980                 {
7981                   tree sop, uop;
7982
7983                   if (op0_signed)
7984                     sop = xop0, uop = xop1;
7985                   else
7986                     sop = xop1, uop = xop0;
7987
7988                   /* Do not warn if the signed quantity is an
7989                      unsuffixed integer literal (or some static
7990                      constant expression involving such literals or a
7991                      conditional expression involving such literals)
7992                      and it is non-negative.  */
7993                   if (tree_expr_nonnegative_p (sop))
7994                     /* OK */;
7995                   /* Do not warn if the comparison is an equality operation,
7996                      the unsigned quantity is an integral constant, and it
7997                      would fit in the result if the result were signed.  */
7998                   else if (TREE_CODE (uop) == INTEGER_CST
7999                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8000                            && int_fits_type_p
8001                            (uop, c_common_signed_type (result_type)))
8002                     /* OK */;
8003                   /* Do not warn if the unsigned quantity is an enumeration
8004                      constant and its maximum value would fit in the result
8005                      if the result were signed.  */
8006                   else if (TREE_CODE (uop) == INTEGER_CST
8007                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8008                            && int_fits_type_p
8009                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8010                             c_common_signed_type (result_type)))
8011                     /* OK */;
8012                   else
8013                     warning (0, "comparison between signed and unsigned");
8014                 }
8015
8016               /* Warn if two unsigned values are being compared in a size
8017                  larger than their original size, and one (and only one) is the
8018                  result of a `~' operator.  This comparison will always fail.
8019
8020                  Also warn if one operand is a constant, and the constant
8021                  does not have all bits set that are set in the ~ operand
8022                  when it is extended.  */
8023
8024               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8025                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8026                 {
8027                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8028                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8029                                             &unsignedp0);
8030                   else
8031                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8032                                             &unsignedp1);
8033
8034                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8035                     {
8036                       tree primop;
8037                       HOST_WIDE_INT constant, mask;
8038                       int unsignedp, bits;
8039
8040                       if (host_integerp (primop0, 0))
8041                         {
8042                           primop = primop1;
8043                           unsignedp = unsignedp1;
8044                           constant = tree_low_cst (primop0, 0);
8045                         }
8046                       else
8047                         {
8048                           primop = primop0;
8049                           unsignedp = unsignedp0;
8050                           constant = tree_low_cst (primop1, 0);
8051                         }
8052
8053                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8054                       if (bits < TYPE_PRECISION (result_type)
8055                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8056                         {
8057                           mask = (~(HOST_WIDE_INT) 0) << bits;
8058                           if ((mask & constant) != mask)
8059                             warning (0, "comparison of promoted ~unsigned with constant");
8060                         }
8061                     }
8062                   else if (unsignedp0 && unsignedp1
8063                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8064                                < TYPE_PRECISION (result_type))
8065                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8066                                < TYPE_PRECISION (result_type)))
8067                     warning (0, "comparison of promoted ~unsigned with unsigned");
8068                 }
8069             }
8070         }
8071     }
8072
8073   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8074      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8075      Then the expression will be built.
8076      It will be given type FINAL_TYPE if that is nonzero;
8077      otherwise, it will be given type RESULT_TYPE.  */
8078
8079   if (!result_type)
8080     {
8081       binary_op_error (code);
8082       return error_mark_node;
8083     }
8084
8085   if (!converted)
8086     {
8087       if (TREE_TYPE (op0) != result_type)
8088         op0 = convert (result_type, op0);
8089       if (TREE_TYPE (op1) != result_type)
8090         op1 = convert (result_type, op1);
8091
8092       /* This can happen if one operand has a vector type, and the other
8093          has a different type.  */
8094       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8095         return error_mark_node;
8096     }
8097
8098   if (build_type == NULL_TREE)
8099     build_type = result_type;
8100
8101   {
8102     tree result = build2 (resultcode, build_type, op0, op1);
8103
8104     /* Treat expressions in initializers specially as they can't trap.  */
8105     result = require_constant_value ? fold_initializer (result)
8106                                     : fold (result);
8107
8108     if (final_type != 0)
8109       result = convert (final_type, result);
8110     return result;
8111   }
8112 }
8113
8114
8115 /* Convert EXPR to be a truth-value, validating its type for this
8116    purpose.  */
8117
8118 tree
8119 c_objc_common_truthvalue_conversion (tree expr)
8120 {
8121   switch (TREE_CODE (TREE_TYPE (expr)))
8122     {
8123     case ARRAY_TYPE:
8124       error ("used array that cannot be converted to pointer where scalar is required");
8125       return error_mark_node;
8126
8127     case RECORD_TYPE:
8128       error ("used struct type value where scalar is required");
8129       return error_mark_node;
8130
8131     case UNION_TYPE:
8132       error ("used union type value where scalar is required");
8133       return error_mark_node;
8134
8135     case FUNCTION_TYPE:
8136       gcc_unreachable ();
8137
8138     default:
8139       break;
8140     }
8141
8142   /* ??? Should we also give an error for void and vectors rather than
8143      leaving those to give errors later?  */
8144   return c_common_truthvalue_conversion (expr);
8145 }
8146 \f
8147
8148 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8149    required.  */
8150
8151 tree
8152 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8153                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8154 {
8155   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8156     {
8157       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8158       /* Executing a compound literal inside a function reinitializes
8159          it.  */
8160       if (!TREE_STATIC (decl))
8161         *se = true;
8162       return decl;
8163     }
8164   else
8165     return expr;
8166 }