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, 0));
2065           else
2066             rhs = fold_build1 (NOP_EXPR, return_type, integer_zero_node);
2067
2068           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2069         }
2070     }
2071
2072   /* Convert the parameters to the types declared in the
2073      function prototype, or apply default promotions.  */
2074
2075   coerced_params
2076     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2077
2078   if (coerced_params == error_mark_node)
2079     return error_mark_node;
2080
2081   /* Check that the arguments to the function are valid.  */
2082
2083   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2084                             TYPE_ARG_TYPES (fntype));
2085
2086   result = build3 (CALL_EXPR, TREE_TYPE (fntype),
2087                    function, coerced_params, NULL_TREE);
2088   TREE_SIDE_EFFECTS (result) = 1;
2089
2090   if (require_constant_value)
2091     {
2092       result = fold_initializer (result);
2093
2094       if (TREE_CONSTANT (result)
2095           && (name == NULL_TREE
2096               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2097         pedwarn_init ("initializer element is not constant");
2098     }
2099   else
2100     result = fold (result);
2101
2102   if (VOID_TYPE_P (TREE_TYPE (result)))
2103     return result;
2104   return require_complete_type (result);
2105 }
2106 \f
2107 /* Convert the argument expressions in the list VALUES
2108    to the types in the list TYPELIST.  The result is a list of converted
2109    argument expressions, unless there are too few arguments in which
2110    case it is error_mark_node.
2111
2112    If TYPELIST is exhausted, or when an element has NULL as its type,
2113    perform the default conversions.
2114
2115    PARMLIST is the chain of parm decls for the function being called.
2116    It may be 0, if that info is not available.
2117    It is used only for generating error messages.
2118
2119    FUNCTION is a tree for the called function.  It is used only for
2120    error messages, where it is formatted with %qE.
2121
2122    This is also where warnings about wrong number of args are generated.
2123
2124    Both VALUES and the returned value are chains of TREE_LIST nodes
2125    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2126
2127 static tree
2128 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2129 {
2130   tree typetail, valtail;
2131   tree result = NULL;
2132   int parmnum;
2133   tree selector;
2134
2135   /* Change pointer to function to the function itself for
2136      diagnostics.  */
2137   if (TREE_CODE (function) == ADDR_EXPR
2138       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2139     function = TREE_OPERAND (function, 0);
2140
2141   /* Handle an ObjC selector specially for diagnostics.  */
2142   selector = objc_message_selector ();
2143
2144   /* Scan the given expressions and types, producing individual
2145      converted arguments and pushing them on RESULT in reverse order.  */
2146
2147   for (valtail = values, typetail = typelist, parmnum = 0;
2148        valtail;
2149        valtail = TREE_CHAIN (valtail), parmnum++)
2150     {
2151       tree type = typetail ? TREE_VALUE (typetail) : 0;
2152       tree val = TREE_VALUE (valtail);
2153       tree rname = function;
2154       int argnum = parmnum + 1;
2155       const char *invalid_func_diag;
2156
2157       if (type == void_type_node)
2158         {
2159           error ("too many arguments to function %qE", function);
2160           break;
2161         }
2162
2163       if (selector && argnum > 2)
2164         {
2165           rname = selector;
2166           argnum -= 2;
2167         }
2168
2169       STRIP_TYPE_NOPS (val);
2170
2171       val = require_complete_type (val);
2172
2173       if (type != 0)
2174         {
2175           /* Formal parm type is specified by a function prototype.  */
2176           tree parmval;
2177
2178           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2179             {
2180               error ("type of formal parameter %d is incomplete", parmnum + 1);
2181               parmval = val;
2182             }
2183           else
2184             {
2185               /* Optionally warn about conversions that
2186                  differ from the default conversions.  */
2187               if (warn_conversion || warn_traditional)
2188                 {
2189                   unsigned int formal_prec = TYPE_PRECISION (type);
2190
2191                   if (INTEGRAL_TYPE_P (type)
2192                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2193                     warning (0, "passing argument %d of %qE as integer "
2194                              "rather than floating due to prototype",
2195                              argnum, rname);
2196                   if (INTEGRAL_TYPE_P (type)
2197                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2198                     warning (0, "passing argument %d of %qE as integer "
2199                              "rather than complex due to prototype",
2200                              argnum, rname);
2201                   else if (TREE_CODE (type) == COMPLEX_TYPE
2202                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2203                     warning (0, "passing argument %d of %qE as complex "
2204                              "rather than floating due to prototype",
2205                              argnum, rname);
2206                   else if (TREE_CODE (type) == REAL_TYPE
2207                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2208                     warning (0, "passing argument %d of %qE as floating "
2209                              "rather than integer due to prototype",
2210                              argnum, rname);
2211                   else if (TREE_CODE (type) == COMPLEX_TYPE
2212                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2213                     warning (0, "passing argument %d of %qE as complex "
2214                              "rather than integer due to prototype",
2215                              argnum, rname);
2216                   else if (TREE_CODE (type) == REAL_TYPE
2217                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2218                     warning (0, "passing argument %d of %qE as floating "
2219                              "rather than complex due to prototype",
2220                              argnum, rname);
2221                   /* ??? At some point, messages should be written about
2222                      conversions between complex types, but that's too messy
2223                      to do now.  */
2224                   else if (TREE_CODE (type) == REAL_TYPE
2225                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2226                     {
2227                       /* Warn if any argument is passed as `float',
2228                          since without a prototype it would be `double'.  */
2229                       if (formal_prec == TYPE_PRECISION (float_type_node))
2230                         warning (0, "passing argument %d of %qE as %<float%> "
2231                                  "rather than %<double%> due to prototype",
2232                                  argnum, rname);
2233                     }
2234                   /* Detect integer changing in width or signedness.
2235                      These warnings are only activated with
2236                      -Wconversion, not with -Wtraditional.  */
2237                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2238                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2239                     {
2240                       tree would_have_been = default_conversion (val);
2241                       tree type1 = TREE_TYPE (would_have_been);
2242
2243                       if (TREE_CODE (type) == ENUMERAL_TYPE
2244                           && (TYPE_MAIN_VARIANT (type)
2245                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2246                         /* No warning if function asks for enum
2247                            and the actual arg is that enum type.  */
2248                         ;
2249                       else if (formal_prec != TYPE_PRECISION (type1))
2250                         warning (OPT_Wconversion, "passing argument %d of %qE "
2251                                  "with different width due to prototype",
2252                                  argnum, rname);
2253                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2254                         ;
2255                       /* Don't complain if the formal parameter type
2256                          is an enum, because we can't tell now whether
2257                          the value was an enum--even the same enum.  */
2258                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2259                         ;
2260                       else if (TREE_CODE (val) == INTEGER_CST
2261                                && int_fits_type_p (val, type))
2262                         /* Change in signedness doesn't matter
2263                            if a constant value is unaffected.  */
2264                         ;
2265                       /* If the value is extended from a narrower
2266                          unsigned type, it doesn't matter whether we
2267                          pass it as signed or unsigned; the value
2268                          certainly is the same either way.  */
2269                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2270                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2271                         ;
2272                       else if (TYPE_UNSIGNED (type))
2273                         warning (OPT_Wconversion, "passing argument %d of %qE "
2274                                  "as unsigned due to prototype",
2275                                  argnum, rname);
2276                       else
2277                         warning (OPT_Wconversion, "passing argument %d of %qE "
2278                                  "as signed due to prototype", argnum, rname);
2279                     }
2280                 }
2281
2282               parmval = convert_for_assignment (type, val, ic_argpass,
2283                                                 fundecl, function,
2284                                                 parmnum + 1);
2285
2286               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2287                   && INTEGRAL_TYPE_P (type)
2288                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2289                 parmval = default_conversion (parmval);
2290             }
2291           result = tree_cons (NULL_TREE, parmval, result);
2292         }
2293       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2294                && (TYPE_PRECISION (TREE_TYPE (val))
2295                    < TYPE_PRECISION (double_type_node)))
2296         /* Convert `float' to `double'.  */
2297         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2298       else if ((invalid_func_diag =
2299                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2300         {
2301           error (invalid_func_diag);
2302           return error_mark_node;
2303         }
2304       else
2305         /* Convert `short' and `char' to full-size `int'.  */
2306         result = tree_cons (NULL_TREE, default_conversion (val), result);
2307
2308       if (typetail)
2309         typetail = TREE_CHAIN (typetail);
2310     }
2311
2312   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2313     {
2314       error ("too few arguments to function %qE", function);
2315       return error_mark_node;
2316     }
2317
2318   return nreverse (result);
2319 }
2320 \f
2321 /* This is the entry point used by the parser to build unary operators
2322    in the input.  CODE, a tree_code, specifies the unary operator, and
2323    ARG is the operand.  For unary plus, the C parser currently uses
2324    CONVERT_EXPR for code.  */
2325
2326 struct c_expr
2327 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2328 {
2329   struct c_expr result;
2330
2331   result.original_code = ERROR_MARK;
2332   result.value = build_unary_op (code, arg.value, 0);
2333   overflow_warning (result.value);
2334   return result;
2335 }
2336
2337 /* This is the entry point used by the parser to build binary operators
2338    in the input.  CODE, a tree_code, specifies the binary operator, and
2339    ARG1 and ARG2 are the operands.  In addition to constructing the
2340    expression, we check for operands that were written with other binary
2341    operators in a way that is likely to confuse the user.  */
2342
2343 struct c_expr
2344 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2345                         struct c_expr arg2)
2346 {
2347   struct c_expr result;
2348
2349   enum tree_code code1 = arg1.original_code;
2350   enum tree_code code2 = arg2.original_code;
2351
2352   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2353   result.original_code = code;
2354
2355   if (TREE_CODE (result.value) == ERROR_MARK)
2356     return result;
2357
2358   /* Check for cases such as x+y<<z which users are likely
2359      to misinterpret.  */
2360   if (warn_parentheses)
2361     {
2362       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2363         {
2364           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2365               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2366             warning (OPT_Wparentheses,
2367                      "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 (OPT_Wparentheses,
2375                      "suggest parentheses around && within ||");
2376         }
2377
2378       if (code == BIT_IOR_EXPR)
2379         {
2380           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2381               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2382               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2383               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2384             warning (OPT_Wparentheses,
2385                      "suggest parentheses around arithmetic in operand of |");
2386           /* Check cases like x|y==z */
2387           if (TREE_CODE_CLASS (code1) == tcc_comparison
2388               || TREE_CODE_CLASS (code2) == tcc_comparison)
2389             warning (OPT_Wparentheses,
2390                      "suggest parentheses around comparison in operand of |");
2391         }
2392
2393       if (code == BIT_XOR_EXPR)
2394         {
2395           if (code1 == BIT_AND_EXPR
2396               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2397               || code2 == BIT_AND_EXPR
2398               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2399             warning (OPT_Wparentheses,
2400                      "suggest parentheses around arithmetic in operand of ^");
2401           /* Check cases like x^y==z */
2402           if (TREE_CODE_CLASS (code1) == tcc_comparison
2403               || TREE_CODE_CLASS (code2) == tcc_comparison)
2404             warning (OPT_Wparentheses,
2405                      "suggest parentheses around comparison in operand of ^");
2406         }
2407
2408       if (code == BIT_AND_EXPR)
2409         {
2410           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2411               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2412             warning (OPT_Wparentheses,
2413                      "suggest parentheses around + or - in operand of &");
2414           /* Check cases like x&y==z */
2415           if (TREE_CODE_CLASS (code1) == tcc_comparison
2416               || TREE_CODE_CLASS (code2) == tcc_comparison)
2417             warning (OPT_Wparentheses,
2418                      "suggest parentheses around comparison in operand of &");
2419         }
2420       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2421       if (TREE_CODE_CLASS (code) == tcc_comparison
2422           && (TREE_CODE_CLASS (code1) == tcc_comparison
2423               || TREE_CODE_CLASS (code2) == tcc_comparison))
2424         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
2425                  "have their mathematical meaning");
2426
2427     }
2428
2429   unsigned_conversion_warning (result.value, arg1.value);
2430   unsigned_conversion_warning (result.value, arg2.value);
2431   overflow_warning (result.value);
2432
2433   return result;
2434 }
2435 \f
2436 /* Return a tree for the difference of pointers OP0 and OP1.
2437    The resulting tree has type int.  */
2438
2439 static tree
2440 pointer_diff (tree op0, tree op1)
2441 {
2442   tree restype = ptrdiff_type_node;
2443
2444   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2445   tree con0, con1, lit0, lit1;
2446   tree orig_op1 = op1;
2447
2448   if (pedantic || warn_pointer_arith)
2449     {
2450       if (TREE_CODE (target_type) == VOID_TYPE)
2451         pedwarn ("pointer of type %<void *%> used in subtraction");
2452       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2453         pedwarn ("pointer to a function used in subtraction");
2454     }
2455
2456   /* If the conversion to ptrdiff_type does anything like widening or
2457      converting a partial to an integral mode, we get a convert_expression
2458      that is in the way to do any simplifications.
2459      (fold-const.c doesn't know that the extra bits won't be needed.
2460      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2461      different mode in place.)
2462      So first try to find a common term here 'by hand'; we want to cover
2463      at least the cases that occur in legal static initializers.  */
2464   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2465   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2466
2467   if (TREE_CODE (con0) == PLUS_EXPR)
2468     {
2469       lit0 = TREE_OPERAND (con0, 1);
2470       con0 = TREE_OPERAND (con0, 0);
2471     }
2472   else
2473     lit0 = integer_zero_node;
2474
2475   if (TREE_CODE (con1) == PLUS_EXPR)
2476     {
2477       lit1 = TREE_OPERAND (con1, 1);
2478       con1 = TREE_OPERAND (con1, 0);
2479     }
2480   else
2481     lit1 = integer_zero_node;
2482
2483   if (operand_equal_p (con0, con1, 0))
2484     {
2485       op0 = lit0;
2486       op1 = lit1;
2487     }
2488
2489
2490   /* First do the subtraction as integers;
2491      then drop through to build the divide operator.
2492      Do not do default conversions on the minus operator
2493      in case restype is a short type.  */
2494
2495   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2496                          convert (restype, op1), 0);
2497   /* This generates an error if op1 is pointer to incomplete type.  */
2498   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2499     error ("arithmetic on pointer to an incomplete type");
2500
2501   /* This generates an error if op0 is pointer to incomplete type.  */
2502   op1 = c_size_in_bytes (target_type);
2503
2504   /* Divide by the size, in easiest possible way.  */
2505   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2506 }
2507 \f
2508 /* Construct and perhaps optimize a tree representation
2509    for a unary operation.  CODE, a tree_code, specifies the operation
2510    and XARG is the operand.
2511    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2512    the default promotions (such as from short to int).
2513    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2514    allows non-lvalues; this is only used to handle conversion of non-lvalue
2515    arrays to pointers in C99.  */
2516
2517 tree
2518 build_unary_op (enum tree_code code, tree xarg, int flag)
2519 {
2520   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2521   tree arg = xarg;
2522   tree argtype = 0;
2523   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2524   tree val;
2525   int noconvert = flag;
2526   const char *invalid_op_diag;
2527
2528   if (typecode == ERROR_MARK)
2529     return error_mark_node;
2530   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2531     typecode = INTEGER_TYPE;
2532
2533   if ((invalid_op_diag
2534        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2535     {
2536       error (invalid_op_diag);
2537       return error_mark_node;
2538     }
2539
2540   switch (code)
2541     {
2542     case CONVERT_EXPR:
2543       /* This is used for unary plus, because a CONVERT_EXPR
2544          is enough to prevent anybody from looking inside for
2545          associativity, but won't generate any code.  */
2546       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2547             || typecode == COMPLEX_TYPE
2548             || typecode == VECTOR_TYPE))
2549         {
2550           error ("wrong type argument to unary plus");
2551           return error_mark_node;
2552         }
2553       else if (!noconvert)
2554         arg = default_conversion (arg);
2555       arg = non_lvalue (arg);
2556       break;
2557
2558     case NEGATE_EXPR:
2559       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2560             || typecode == COMPLEX_TYPE
2561             || typecode == VECTOR_TYPE))
2562         {
2563           error ("wrong type argument to unary minus");
2564           return error_mark_node;
2565         }
2566       else if (!noconvert)
2567         arg = default_conversion (arg);
2568       break;
2569
2570     case BIT_NOT_EXPR:
2571       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2572         {
2573           if (!noconvert)
2574             arg = default_conversion (arg);
2575         }
2576       else if (typecode == COMPLEX_TYPE)
2577         {
2578           code = CONJ_EXPR;
2579           if (pedantic)
2580             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2581           if (!noconvert)
2582             arg = default_conversion (arg);
2583         }
2584       else
2585         {
2586           error ("wrong type argument to bit-complement");
2587           return error_mark_node;
2588         }
2589       break;
2590
2591     case ABS_EXPR:
2592       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2593         {
2594           error ("wrong type argument to abs");
2595           return error_mark_node;
2596         }
2597       else if (!noconvert)
2598         arg = default_conversion (arg);
2599       break;
2600
2601     case CONJ_EXPR:
2602       /* Conjugating a real value is a no-op, but allow it anyway.  */
2603       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2604             || typecode == COMPLEX_TYPE))
2605         {
2606           error ("wrong type argument to conjugation");
2607           return error_mark_node;
2608         }
2609       else if (!noconvert)
2610         arg = default_conversion (arg);
2611       break;
2612
2613     case TRUTH_NOT_EXPR:
2614       if (typecode != INTEGER_TYPE
2615           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2616           && typecode != COMPLEX_TYPE)
2617         {
2618           error ("wrong type argument to unary exclamation mark");
2619           return error_mark_node;
2620         }
2621       arg = c_objc_common_truthvalue_conversion (arg);
2622       return invert_truthvalue (arg);
2623
2624     case NOP_EXPR:
2625       break;
2626
2627     case REALPART_EXPR:
2628       if (TREE_CODE (arg) == COMPLEX_CST)
2629         return TREE_REALPART (arg);
2630       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2631         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2632       else
2633         return arg;
2634
2635     case IMAGPART_EXPR:
2636       if (TREE_CODE (arg) == COMPLEX_CST)
2637         return TREE_IMAGPART (arg);
2638       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2639         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2640       else
2641         return convert (TREE_TYPE (arg), integer_zero_node);
2642
2643     case PREINCREMENT_EXPR:
2644     case POSTINCREMENT_EXPR:
2645     case PREDECREMENT_EXPR:
2646     case POSTDECREMENT_EXPR:
2647
2648       /* Increment or decrement the real part of the value,
2649          and don't change the imaginary part.  */
2650       if (typecode == COMPLEX_TYPE)
2651         {
2652           tree real, imag;
2653
2654           if (pedantic)
2655             pedwarn ("ISO C does not support %<++%> and %<--%>"
2656                      " on complex types");
2657
2658           arg = stabilize_reference (arg);
2659           real = build_unary_op (REALPART_EXPR, arg, 1);
2660           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2661           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2662                          build_unary_op (code, real, 1), imag);
2663         }
2664
2665       /* Report invalid types.  */
2666
2667       if (typecode != POINTER_TYPE
2668           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2669         {
2670           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2671             error ("wrong type argument to increment");
2672           else
2673             error ("wrong type argument to decrement");
2674
2675           return error_mark_node;
2676         }
2677
2678       {
2679         tree inc;
2680         tree result_type = TREE_TYPE (arg);
2681
2682         arg = get_unwidened (arg, 0);
2683         argtype = TREE_TYPE (arg);
2684
2685         /* Compute the increment.  */
2686
2687         if (typecode == POINTER_TYPE)
2688           {
2689             /* If pointer target is an undefined struct,
2690                we just cannot know how to do the arithmetic.  */
2691             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2692               {
2693                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2694                   error ("increment of pointer to unknown structure");
2695                 else
2696                   error ("decrement of pointer to unknown structure");
2697               }
2698             else if ((pedantic || warn_pointer_arith)
2699                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2700                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2701               {
2702                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2703                   pedwarn ("wrong type argument to increment");
2704                 else
2705                   pedwarn ("wrong type argument to decrement");
2706               }
2707
2708             inc = c_size_in_bytes (TREE_TYPE (result_type));
2709           }
2710         else
2711           inc = integer_one_node;
2712
2713         inc = convert (argtype, inc);
2714
2715         /* Complain about anything else that is not a true lvalue.  */
2716         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2717                                     || code == POSTINCREMENT_EXPR)
2718                                    ? lv_increment
2719                                    : lv_decrement)))
2720           return error_mark_node;
2721
2722         /* Report a read-only lvalue.  */
2723         if (TREE_READONLY (arg))
2724           readonly_error (arg,
2725                           ((code == PREINCREMENT_EXPR
2726                             || code == POSTINCREMENT_EXPR)
2727                            ? lv_increment : lv_decrement));
2728
2729         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2730           val = boolean_increment (code, arg);
2731         else
2732           val = build2 (code, TREE_TYPE (arg), arg, inc);
2733         TREE_SIDE_EFFECTS (val) = 1;
2734         val = convert (result_type, val);
2735         if (TREE_CODE (val) != code)
2736           TREE_NO_WARNING (val) = 1;
2737         return val;
2738       }
2739
2740     case ADDR_EXPR:
2741       /* Note that this operation never does default_conversion.  */
2742
2743       /* Let &* cancel out to simplify resulting code.  */
2744       if (TREE_CODE (arg) == INDIRECT_REF)
2745         {
2746           /* Don't let this be an lvalue.  */
2747           if (lvalue_p (TREE_OPERAND (arg, 0)))
2748             return non_lvalue (TREE_OPERAND (arg, 0));
2749           return TREE_OPERAND (arg, 0);
2750         }
2751
2752       /* For &x[y], return x+y */
2753       if (TREE_CODE (arg) == ARRAY_REF)
2754         {
2755           tree op0 = TREE_OPERAND (arg, 0);
2756           if (!c_mark_addressable (op0))
2757             return error_mark_node;
2758           return build_binary_op (PLUS_EXPR,
2759                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2760                                    ? array_to_pointer_conversion (op0)
2761                                    : op0),
2762                                   TREE_OPERAND (arg, 1), 1);
2763         }
2764
2765       /* Anything not already handled and not a true memory reference
2766          or a non-lvalue array is an error.  */
2767       else if (typecode != FUNCTION_TYPE && !flag
2768                && !lvalue_or_else (arg, lv_addressof))
2769         return error_mark_node;
2770
2771       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2772       argtype = TREE_TYPE (arg);
2773
2774       /* If the lvalue is const or volatile, merge that into the type
2775          to which the address will point.  Note that you can't get a
2776          restricted pointer by taking the address of something, so we
2777          only have to deal with `const' and `volatile' here.  */
2778       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2779           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2780           argtype = c_build_type_variant (argtype,
2781                                           TREE_READONLY (arg),
2782                                           TREE_THIS_VOLATILE (arg));
2783
2784       if (!c_mark_addressable (arg))
2785         return error_mark_node;
2786
2787       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2788                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2789
2790       argtype = build_pointer_type (argtype);
2791
2792       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2793          when we have proper support for integer constant expressions.  */
2794       val = get_base_address (arg);
2795       if (val && TREE_CODE (val) == INDIRECT_REF
2796           && integer_zerop (TREE_OPERAND (val, 0)))
2797         return fold_convert (argtype, fold_offsetof (arg));
2798
2799       val = build1 (ADDR_EXPR, argtype, arg);
2800
2801       return val;
2802
2803     default:
2804       break;
2805     }
2806
2807   if (argtype == 0)
2808     argtype = TREE_TYPE (arg);
2809   val = build1 (code, argtype, arg);
2810   return require_constant_value ? fold_initializer (val) : fold (val);
2811 }
2812
2813 /* Return nonzero if REF is an lvalue valid for this language.
2814    Lvalues can be assigned, unless their type has TYPE_READONLY.
2815    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2816
2817 static int
2818 lvalue_p (tree ref)
2819 {
2820   enum tree_code code = TREE_CODE (ref);
2821
2822   switch (code)
2823     {
2824     case REALPART_EXPR:
2825     case IMAGPART_EXPR:
2826     case COMPONENT_REF:
2827       return lvalue_p (TREE_OPERAND (ref, 0));
2828
2829     case COMPOUND_LITERAL_EXPR:
2830     case STRING_CST:
2831       return 1;
2832
2833     case INDIRECT_REF:
2834     case ARRAY_REF:
2835     case VAR_DECL:
2836     case PARM_DECL:
2837     case RESULT_DECL:
2838     case ERROR_MARK:
2839       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2840               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2841
2842     case BIND_EXPR:
2843       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2844
2845     default:
2846       return 0;
2847     }
2848 }
2849 \f
2850 /* Give an error for storing in something that is 'const'.  */
2851
2852 static void
2853 readonly_error (tree arg, enum lvalue_use use)
2854 {
2855   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement);
2856   /* Using this macro rather than (for example) arrays of messages
2857      ensures that all the format strings are checked at compile
2858      time.  */
2859 #define READONLY_MSG(A, I, D) (use == lv_assign                         \
2860                                ? (A)                                    \
2861                                : (use == lv_increment ? (I) : (D)))
2862   if (TREE_CODE (arg) == COMPONENT_REF)
2863     {
2864       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2865         readonly_error (TREE_OPERAND (arg, 0), use);
2866       else
2867         error (READONLY_MSG (G_("assignment of read-only member %qD"),
2868                              G_("increment of read-only member %qD"),
2869                              G_("decrement of read-only member %qD")),
2870                TREE_OPERAND (arg, 1));
2871     }
2872   else if (TREE_CODE (arg) == VAR_DECL)
2873     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
2874                          G_("increment of read-only variable %qD"),
2875                          G_("decrement of read-only variable %qD")),
2876            arg);
2877   else
2878     error (READONLY_MSG (G_("assignment of read-only location"),
2879                          G_("increment of read-only location"),
2880                          G_("decrement of read-only location")));
2881 }
2882
2883
2884 /* Return nonzero if REF is an lvalue valid for this language;
2885    otherwise, print an error message and return zero.  USE says
2886    how the lvalue is being used and so selects the error message.  */
2887
2888 static int
2889 lvalue_or_else (tree ref, enum lvalue_use use)
2890 {
2891   int win = lvalue_p (ref);
2892
2893   if (!win)
2894     lvalue_error (use);
2895
2896   return win;
2897 }
2898 \f
2899 /* Mark EXP saying that we need to be able to take the
2900    address of it; it should not be allocated in a register.
2901    Returns true if successful.  */
2902
2903 bool
2904 c_mark_addressable (tree exp)
2905 {
2906   tree x = exp;
2907
2908   while (1)
2909     switch (TREE_CODE (x))
2910       {
2911       case COMPONENT_REF:
2912         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2913           {
2914             error
2915               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
2916             return false;
2917           }
2918
2919         /* ... fall through ...  */
2920
2921       case ADDR_EXPR:
2922       case ARRAY_REF:
2923       case REALPART_EXPR:
2924       case IMAGPART_EXPR:
2925         x = TREE_OPERAND (x, 0);
2926         break;
2927
2928       case COMPOUND_LITERAL_EXPR:
2929       case CONSTRUCTOR:
2930         TREE_ADDRESSABLE (x) = 1;
2931         return true;
2932
2933       case VAR_DECL:
2934       case CONST_DECL:
2935       case PARM_DECL:
2936       case RESULT_DECL:
2937         if (C_DECL_REGISTER (x)
2938             && DECL_NONLOCAL (x))
2939           {
2940             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2941               {
2942                 error
2943                   ("global register variable %qD used in nested function", x);
2944                 return false;
2945               }
2946             pedwarn ("register variable %qD used in nested function", x);
2947           }
2948         else if (C_DECL_REGISTER (x))
2949           {
2950             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2951               error ("address of global register variable %qD requested", x);
2952             else
2953               error ("address of register variable %qD requested", x);
2954             return false;
2955           }
2956
2957         /* drops in */
2958       case FUNCTION_DECL:
2959         TREE_ADDRESSABLE (x) = 1;
2960         /* drops out */
2961       default:
2962         return true;
2963     }
2964 }
2965 \f
2966 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2967
2968 tree
2969 build_conditional_expr (tree ifexp, tree op1, tree op2)
2970 {
2971   tree type1;
2972   tree type2;
2973   enum tree_code code1;
2974   enum tree_code code2;
2975   tree result_type = NULL;
2976   tree orig_op1 = op1, orig_op2 = op2;
2977
2978   /* Promote both alternatives.  */
2979
2980   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
2981     op1 = default_conversion (op1);
2982   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
2983     op2 = default_conversion (op2);
2984
2985   if (TREE_CODE (ifexp) == ERROR_MARK
2986       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
2987       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
2988     return error_mark_node;
2989
2990   type1 = TREE_TYPE (op1);
2991   code1 = TREE_CODE (type1);
2992   type2 = TREE_TYPE (op2);
2993   code2 = TREE_CODE (type2);
2994
2995   /* C90 does not permit non-lvalue arrays in conditional expressions.
2996      In C99 they will be pointers by now.  */
2997   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
2998     {
2999       error ("non-lvalue array in conditional expression");
3000       return error_mark_node;
3001     }
3002
3003   /* Quickly detect the usual case where op1 and op2 have the same type
3004      after promotion.  */
3005   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3006     {
3007       if (type1 == type2)
3008         result_type = type1;
3009       else
3010         result_type = TYPE_MAIN_VARIANT (type1);
3011     }
3012   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3013             || code1 == COMPLEX_TYPE)
3014            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3015                || code2 == COMPLEX_TYPE))
3016     {
3017       result_type = c_common_type (type1, type2);
3018
3019       /* If -Wsign-compare, warn here if type1 and type2 have
3020          different signedness.  We'll promote the signed to unsigned
3021          and later code won't know it used to be different.
3022          Do this check on the original types, so that explicit casts
3023          will be considered, but default promotions won't.  */
3024       if (warn_sign_compare && !skip_evaluation)
3025         {
3026           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3027           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3028
3029           if (unsigned_op1 ^ unsigned_op2)
3030             {
3031               /* Do not warn if the result type is signed, since the
3032                  signed type will only be chosen if it can represent
3033                  all the values of the unsigned type.  */
3034               if (!TYPE_UNSIGNED (result_type))
3035                 /* OK */;
3036               /* Do not warn if the signed quantity is an unsuffixed
3037                  integer literal (or some static constant expression
3038                  involving such literals) and it is non-negative.  */
3039               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3040                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3041                 /* OK */;
3042               else
3043                 warning (0, "signed and unsigned type in conditional expression");
3044             }
3045         }
3046     }
3047   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3048     {
3049       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3050         pedwarn ("ISO C forbids conditional expr with only one void side");
3051       result_type = void_type_node;
3052     }
3053   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3054     {
3055       if (comp_target_types (type1, type2))
3056         result_type = common_pointer_type (type1, type2);
3057       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3058                && TREE_CODE (orig_op1) != NOP_EXPR)
3059         result_type = qualify_type (type2, type1);
3060       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3061                && TREE_CODE (orig_op2) != NOP_EXPR)
3062         result_type = qualify_type (type1, type2);
3063       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3064         {
3065           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == 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 (type1),
3069                                                           TREE_TYPE (type2)));
3070         }
3071       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3072         {
3073           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3074             pedwarn ("ISO C forbids conditional expr between "
3075                      "%<void *%> and function pointer");
3076           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3077                                                           TREE_TYPE (type1)));
3078         }
3079       else
3080         {
3081           pedwarn ("pointer type mismatch in conditional expression");
3082           result_type = build_pointer_type (void_type_node);
3083         }
3084     }
3085   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3086     {
3087       if (!integer_zerop (op2))
3088         pedwarn ("pointer/integer type mismatch in conditional expression");
3089       else
3090         {
3091           op2 = null_pointer_node;
3092         }
3093       result_type = type1;
3094     }
3095   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3096     {
3097       if (!integer_zerop (op1))
3098         pedwarn ("pointer/integer type mismatch in conditional expression");
3099       else
3100         {
3101           op1 = null_pointer_node;
3102         }
3103       result_type = type2;
3104     }
3105
3106   if (!result_type)
3107     {
3108       if (flag_cond_mismatch)
3109         result_type = void_type_node;
3110       else
3111         {
3112           error ("type mismatch in conditional expression");
3113           return error_mark_node;
3114         }
3115     }
3116
3117   /* Merge const and volatile flags of the incoming types.  */
3118   result_type
3119     = build_type_variant (result_type,
3120                           TREE_READONLY (op1) || TREE_READONLY (op2),
3121                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3122
3123   if (result_type != TREE_TYPE (op1))
3124     op1 = convert_and_check (result_type, op1);
3125   if (result_type != TREE_TYPE (op2))
3126     op2 = convert_and_check (result_type, op2);
3127
3128   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3129 }
3130 \f
3131 /* Return a compound expression that performs two expressions and
3132    returns the value of the second of them.  */
3133
3134 tree
3135 build_compound_expr (tree expr1, tree expr2)
3136 {
3137   if (!TREE_SIDE_EFFECTS (expr1))
3138     {
3139       /* The left-hand operand of a comma expression is like an expression
3140          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3141          any side-effects, unless it was explicitly cast to (void).  */
3142       if (warn_unused_value)
3143         {
3144           if (VOID_TYPE_P (TREE_TYPE (expr1))
3145               && TREE_CODE (expr1) == CONVERT_EXPR)
3146             ; /* (void) a, b */
3147           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3148                    && TREE_CODE (expr1) == COMPOUND_EXPR
3149                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3150             ; /* (void) a, (void) b, c */
3151           else
3152             warning (0, "left-hand operand of comma expression has no effect");
3153         }
3154     }
3155
3156   /* With -Wunused, we should also warn if the left-hand operand does have
3157      side-effects, but computes a value which is not used.  For example, in
3158      `foo() + bar(), baz()' the result of the `+' operator is not used,
3159      so we should issue a warning.  */
3160   else if (warn_unused_value)
3161     warn_if_unused_value (expr1, input_location);
3162
3163   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3164 }
3165
3166 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3167
3168 tree
3169 build_c_cast (tree type, tree expr)
3170 {
3171   tree value = expr;
3172
3173   if (type == error_mark_node || expr == error_mark_node)
3174     return error_mark_node;
3175
3176   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3177      only in <protocol> qualifications.  But when constructing cast expressions,
3178      the protocols do matter and must be kept around.  */
3179   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3180     return build1 (NOP_EXPR, type, expr);
3181
3182   type = TYPE_MAIN_VARIANT (type);
3183
3184   if (TREE_CODE (type) == ARRAY_TYPE)
3185     {
3186       error ("cast specifies array type");
3187       return error_mark_node;
3188     }
3189
3190   if (TREE_CODE (type) == FUNCTION_TYPE)
3191     {
3192       error ("cast specifies function type");
3193       return error_mark_node;
3194     }
3195
3196   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3197     {
3198       if (pedantic)
3199         {
3200           if (TREE_CODE (type) == RECORD_TYPE
3201               || TREE_CODE (type) == UNION_TYPE)
3202             pedwarn ("ISO C forbids casting nonscalar to the same type");
3203         }
3204     }
3205   else if (TREE_CODE (type) == UNION_TYPE)
3206     {
3207       tree field;
3208
3209       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3210         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3211                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3212           break;
3213
3214       if (field)
3215         {
3216           tree t;
3217
3218           if (pedantic)
3219             pedwarn ("ISO C forbids casts to union type");
3220           t = digest_init (type,
3221                            build_constructor_single (type, field, value),
3222                            true, 0);
3223           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3224           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3225           return t;
3226         }
3227       error ("cast to union type from type not present in union");
3228       return error_mark_node;
3229     }
3230   else
3231     {
3232       tree otype, ovalue;
3233
3234       if (type == void_type_node)
3235         return build1 (CONVERT_EXPR, type, value);
3236
3237       otype = TREE_TYPE (value);
3238
3239       /* Optionally warn about potentially worrisome casts.  */
3240
3241       if (warn_cast_qual
3242           && TREE_CODE (type) == POINTER_TYPE
3243           && TREE_CODE (otype) == POINTER_TYPE)
3244         {
3245           tree in_type = type;
3246           tree in_otype = otype;
3247           int added = 0;
3248           int discarded = 0;
3249
3250           /* Check that the qualifiers on IN_TYPE are a superset of
3251              the qualifiers of IN_OTYPE.  The outermost level of
3252              POINTER_TYPE nodes is uninteresting and we stop as soon
3253              as we hit a non-POINTER_TYPE node on either type.  */
3254           do
3255             {
3256               in_otype = TREE_TYPE (in_otype);
3257               in_type = TREE_TYPE (in_type);
3258
3259               /* GNU C allows cv-qualified function types.  'const'
3260                  means the function is very pure, 'volatile' means it
3261                  can't return.  We need to warn when such qualifiers
3262                  are added, not when they're taken away.  */
3263               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3264                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3265                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3266               else
3267                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3268             }
3269           while (TREE_CODE (in_type) == POINTER_TYPE
3270                  && TREE_CODE (in_otype) == POINTER_TYPE);
3271
3272           if (added)
3273             warning (0, "cast adds new qualifiers to function type");
3274
3275           if (discarded)
3276             /* There are qualifiers present in IN_OTYPE that are not
3277                present in IN_TYPE.  */
3278             warning (0, "cast discards qualifiers from pointer target type");
3279         }
3280
3281       /* Warn about possible alignment problems.  */
3282       if (STRICT_ALIGNMENT
3283           && TREE_CODE (type) == POINTER_TYPE
3284           && TREE_CODE (otype) == POINTER_TYPE
3285           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3286           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3287           /* Don't warn about opaque types, where the actual alignment
3288              restriction is unknown.  */
3289           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3290                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3291                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3292           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3293         warning (OPT_Wcast_align,
3294                  "cast increases required alignment of target type");
3295
3296       if (TREE_CODE (type) == INTEGER_TYPE
3297           && TREE_CODE (otype) == POINTER_TYPE
3298           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3299           && !TREE_CONSTANT (value))
3300         warning (OPT_Wpointer_to_int_cast,
3301                  "cast from pointer to integer of different size");
3302
3303       if (TREE_CODE (value) == CALL_EXPR
3304           && TREE_CODE (type) != TREE_CODE (otype))
3305         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3306                  "to non-matching type %qT", otype, type);
3307
3308       if (TREE_CODE (type) == POINTER_TYPE
3309           && TREE_CODE (otype) == INTEGER_TYPE
3310           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3311           /* Don't warn about converting any constant.  */
3312           && !TREE_CONSTANT (value))
3313         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3314                  "of different size");
3315
3316       if (flag_strict_aliasing && warn_strict_aliasing
3317           && TREE_CODE (type) == POINTER_TYPE
3318           && TREE_CODE (otype) == POINTER_TYPE
3319           && TREE_CODE (expr) == ADDR_EXPR
3320           && (DECL_P (TREE_OPERAND (expr, 0))
3321               || TREE_CODE (TREE_OPERAND (expr, 0)) == COMPONENT_REF)
3322           && !VOID_TYPE_P (TREE_TYPE (type)))
3323         {
3324           /* Casting the address of an object to non void pointer. Warn
3325              if the cast breaks type based aliasing.  */
3326           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3327             warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
3328                      "might break strict-aliasing rules");
3329           else
3330             {
3331               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3332               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3333
3334               if (!alias_sets_conflict_p (set1, set2))
3335                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3336                          "pointer will break strict-aliasing rules");
3337               else if (warn_strict_aliasing > 1
3338                        && !alias_sets_might_conflict_p (set1, set2))
3339                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3340                          "pointer might break strict-aliasing rules");
3341             }
3342         }
3343
3344       /* If pedantic, warn for conversions between function and object
3345          pointer types, except for converting a null pointer constant
3346          to function pointer type.  */
3347       if (pedantic
3348           && TREE_CODE (type) == POINTER_TYPE
3349           && TREE_CODE (otype) == POINTER_TYPE
3350           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3351           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3352         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3353
3354       if (pedantic
3355           && TREE_CODE (type) == POINTER_TYPE
3356           && TREE_CODE (otype) == POINTER_TYPE
3357           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3358           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3359           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3360                && TREE_CODE (expr) != NOP_EXPR))
3361         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3362
3363       ovalue = value;
3364       value = convert (type, value);
3365
3366       /* Ignore any integer overflow caused by the cast.  */
3367       if (TREE_CODE (value) == INTEGER_CST)
3368         {
3369           /* If OVALUE had overflow set, then so will VALUE, so it
3370              is safe to overwrite.  */
3371           if (CONSTANT_CLASS_P (ovalue))
3372             {
3373               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3374               /* Similarly, constant_overflow cannot have become cleared.  */
3375               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3376             }
3377           else
3378             TREE_OVERFLOW (value) = 0;
3379         }
3380     }
3381
3382   /* Don't let a cast be an lvalue.  */
3383   if (value == expr)
3384     value = non_lvalue (value);
3385
3386   return value;
3387 }
3388
3389 /* Interpret a cast of expression EXPR to type TYPE.  */
3390 tree
3391 c_cast_expr (struct c_type_name *type_name, tree expr)
3392 {
3393   tree type;
3394   int saved_wsp = warn_strict_prototypes;
3395
3396   /* This avoids warnings about unprototyped casts on
3397      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3398   if (TREE_CODE (expr) == INTEGER_CST)
3399     warn_strict_prototypes = 0;
3400   type = groktypename (type_name);
3401   warn_strict_prototypes = saved_wsp;
3402
3403   return build_c_cast (type, expr);
3404 }
3405
3406 \f
3407 /* Build an assignment expression of lvalue LHS from value RHS.
3408    MODIFYCODE is the code for a binary operator that we use
3409    to combine the old value of LHS with RHS to get the new value.
3410    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3411
3412 tree
3413 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3414 {
3415   tree result;
3416   tree newrhs;
3417   tree lhstype = TREE_TYPE (lhs);
3418   tree olhstype = lhstype;
3419
3420   /* Types that aren't fully specified cannot be used in assignments.  */
3421   lhs = require_complete_type (lhs);
3422
3423   /* Avoid duplicate error messages from operands that had errors.  */
3424   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3425     return error_mark_node;
3426
3427   STRIP_TYPE_NOPS (rhs);
3428
3429   newrhs = rhs;
3430
3431   /* If a binary op has been requested, combine the old LHS value with the RHS
3432      producing the value we should actually store into the LHS.  */
3433
3434   if (modifycode != NOP_EXPR)
3435     {
3436       lhs = stabilize_reference (lhs);
3437       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3438     }
3439
3440   if (!lvalue_or_else (lhs, lv_assign))
3441     return error_mark_node;
3442
3443   /* Give an error for storing in something that is 'const'.  */
3444
3445   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3446       || ((TREE_CODE (lhstype) == RECORD_TYPE
3447            || TREE_CODE (lhstype) == UNION_TYPE)
3448           && C_TYPE_FIELDS_READONLY (lhstype)))
3449     readonly_error (lhs, lv_assign);
3450
3451   /* If storing into a structure or union member,
3452      it has probably been given type `int'.
3453      Compute the type that would go with
3454      the actual amount of storage the member occupies.  */
3455
3456   if (TREE_CODE (lhs) == COMPONENT_REF
3457       && (TREE_CODE (lhstype) == INTEGER_TYPE
3458           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3459           || TREE_CODE (lhstype) == REAL_TYPE
3460           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3461     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3462
3463   /* If storing in a field that is in actuality a short or narrower than one,
3464      we must store in the field in its actual type.  */
3465
3466   if (lhstype != TREE_TYPE (lhs))
3467     {
3468       lhs = copy_node (lhs);
3469       TREE_TYPE (lhs) = lhstype;
3470     }
3471
3472   /* Convert new value to destination type.  */
3473
3474   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3475                                    NULL_TREE, NULL_TREE, 0);
3476   if (TREE_CODE (newrhs) == ERROR_MARK)
3477     return error_mark_node;
3478
3479   /* Emit ObjC write barrier, if necessary.  */
3480   if (c_dialect_objc () && flag_objc_gc)
3481     {
3482       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3483       if (result)
3484         return result;
3485     }
3486
3487   /* Scan operands.  */
3488
3489   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3490   TREE_SIDE_EFFECTS (result) = 1;
3491
3492   /* If we got the LHS in a different type for storing in,
3493      convert the result back to the nominal type of LHS
3494      so that the value we return always has the same type
3495      as the LHS argument.  */
3496
3497   if (olhstype == TREE_TYPE (result))
3498     return result;
3499   return convert_for_assignment (olhstype, result, ic_assign,
3500                                  NULL_TREE, NULL_TREE, 0);
3501 }
3502 \f
3503 /* Convert value RHS to type TYPE as preparation for an assignment
3504    to an lvalue of type TYPE.
3505    The real work of conversion is done by `convert'.
3506    The purpose of this function is to generate error messages
3507    for assignments that are not allowed in C.
3508    ERRTYPE says whether it is argument passing, assignment,
3509    initialization or return.
3510
3511    FUNCTION is a tree for the function being called.
3512    PARMNUM is the number of the argument, for printing in error messages.  */
3513
3514 static tree
3515 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3516                         tree fundecl, tree function, int parmnum)
3517 {
3518   enum tree_code codel = TREE_CODE (type);
3519   tree rhstype;
3520   enum tree_code coder;
3521   tree rname = NULL_TREE;
3522   bool objc_ok = false;
3523
3524   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3525     {
3526       tree selector;
3527       /* Change pointer to function to the function itself for
3528          diagnostics.  */
3529       if (TREE_CODE (function) == ADDR_EXPR
3530           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3531         function = TREE_OPERAND (function, 0);
3532
3533       /* Handle an ObjC selector specially for diagnostics.  */
3534       selector = objc_message_selector ();
3535       rname = function;
3536       if (selector && parmnum > 2)
3537         {
3538           rname = selector;
3539           parmnum -= 2;
3540         }
3541     }
3542
3543   /* This macro is used to emit diagnostics to ensure that all format
3544      strings are complete sentences, visible to gettext and checked at
3545      compile time.  */
3546 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3547   do {                                          \
3548     switch (errtype)                            \
3549       {                                         \
3550       case ic_argpass:                          \
3551         pedwarn (AR, parmnum, rname);           \
3552         break;                                  \
3553       case ic_argpass_nonproto:                 \
3554         warning (0, AR, parmnum, rname);                \
3555         break;                                  \
3556       case ic_assign:                           \
3557         pedwarn (AS);                           \
3558         break;                                  \
3559       case ic_init:                             \
3560         pedwarn (IN);                           \
3561         break;                                  \
3562       case ic_return:                           \
3563         pedwarn (RE);                           \
3564         break;                                  \
3565       default:                                  \
3566         gcc_unreachable ();                     \
3567       }                                         \
3568   } while (0)
3569
3570   STRIP_TYPE_NOPS (rhs);
3571
3572   if (optimize && TREE_CODE (rhs) == VAR_DECL
3573            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3574     rhs = decl_constant_value_for_broken_optimization (rhs);
3575
3576   rhstype = TREE_TYPE (rhs);
3577   coder = TREE_CODE (rhstype);
3578
3579   if (coder == ERROR_MARK)
3580     return error_mark_node;
3581
3582   if (c_dialect_objc ())
3583     {
3584       int parmno;
3585
3586       switch (errtype)
3587         {
3588         case ic_return:
3589           parmno = 0;
3590           break;
3591
3592         case ic_assign:
3593           parmno = -1;
3594           break;
3595
3596         case ic_init:
3597           parmno = -2;
3598           break;
3599
3600         default:
3601           parmno = parmnum;
3602           break;
3603         }
3604
3605       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3606     }
3607
3608   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3609     {
3610       overflow_warning (rhs);
3611       return rhs;
3612     }
3613
3614   if (coder == VOID_TYPE)
3615     {
3616       /* Except for passing an argument to an unprototyped function,
3617          this is a constraint violation.  When passing an argument to
3618          an unprototyped function, it is compile-time undefined;
3619          making it a constraint in that case was rejected in
3620          DR#252.  */
3621       error ("void value not ignored as it ought to be");
3622       return error_mark_node;
3623     }
3624   /* A type converts to a reference to it.
3625      This code doesn't fully support references, it's just for the
3626      special case of va_start and va_copy.  */
3627   if (codel == REFERENCE_TYPE
3628       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3629     {
3630       if (!lvalue_p (rhs))
3631         {
3632           error ("cannot pass rvalue to reference parameter");
3633           return error_mark_node;
3634         }
3635       if (!c_mark_addressable (rhs))
3636         return error_mark_node;
3637       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3638
3639       /* We already know that these two types are compatible, but they
3640          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3641          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3642          likely to be va_list, a typedef to __builtin_va_list, which
3643          is different enough that it will cause problems later.  */
3644       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3645         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3646
3647       rhs = build1 (NOP_EXPR, type, rhs);
3648       return rhs;
3649     }
3650   /* Some types can interconvert without explicit casts.  */
3651   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3652            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3653     return convert (type, rhs);
3654   /* Arithmetic types all interconvert, and enum is treated like int.  */
3655   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3656             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3657             || codel == BOOLEAN_TYPE)
3658            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3659                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3660                || coder == BOOLEAN_TYPE))
3661     return convert_and_check (type, rhs);
3662
3663   /* Conversion to a transparent union from its member types.
3664      This applies only to function arguments.  */
3665   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3666            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3667     {
3668       tree memb_types;
3669       tree marginal_memb_type = 0;
3670
3671       for (memb_types = TYPE_FIELDS (type); memb_types;
3672            memb_types = TREE_CHAIN (memb_types))
3673         {
3674           tree memb_type = TREE_TYPE (memb_types);
3675
3676           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3677                          TYPE_MAIN_VARIANT (rhstype)))
3678             break;
3679
3680           if (TREE_CODE (memb_type) != POINTER_TYPE)
3681             continue;
3682
3683           if (coder == POINTER_TYPE)
3684             {
3685               tree ttl = TREE_TYPE (memb_type);
3686               tree ttr = TREE_TYPE (rhstype);
3687
3688               /* Any non-function converts to a [const][volatile] void *
3689                  and vice versa; otherwise, targets must be the same.
3690                  Meanwhile, the lhs target must have all the qualifiers of
3691                  the rhs.  */
3692               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3693                   || comp_target_types (memb_type, rhstype))
3694                 {
3695                   /* If this type won't generate any warnings, use it.  */
3696                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3697                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3698                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3699                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3700                              == TYPE_QUALS (ttr))
3701                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3702                              == TYPE_QUALS (ttl))))
3703                     break;
3704
3705                   /* Keep looking for a better type, but remember this one.  */
3706                   if (!marginal_memb_type)
3707                     marginal_memb_type = memb_type;
3708                 }
3709             }
3710
3711           /* Can convert integer zero to any pointer type.  */
3712           if (integer_zerop (rhs)
3713               || (TREE_CODE (rhs) == NOP_EXPR
3714                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3715             {
3716               rhs = null_pointer_node;
3717               break;
3718             }
3719         }
3720
3721       if (memb_types || marginal_memb_type)
3722         {
3723           if (!memb_types)
3724             {
3725               /* We have only a marginally acceptable member type;
3726                  it needs a warning.  */
3727               tree ttl = TREE_TYPE (marginal_memb_type);
3728               tree ttr = TREE_TYPE (rhstype);
3729
3730               /* Const and volatile mean something different for function
3731                  types, so the usual warnings are not appropriate.  */
3732               if (TREE_CODE (ttr) == FUNCTION_TYPE
3733                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3734                 {
3735                   /* Because const and volatile on functions are
3736                      restrictions that say the function will not do
3737                      certain things, it is okay to use a const or volatile
3738                      function where an ordinary one is wanted, but not
3739                      vice-versa.  */
3740                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3741                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3742                                             "makes qualified function "
3743                                             "pointer from unqualified"),
3744                                          G_("assignment makes qualified "
3745                                             "function pointer from "
3746                                             "unqualified"),
3747                                          G_("initialization makes qualified "
3748                                             "function pointer from "
3749                                             "unqualified"),
3750                                          G_("return makes qualified function "
3751                                             "pointer from unqualified"));
3752                 }
3753               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3754                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3755                                         "qualifiers from pointer target type"),
3756                                      G_("assignment discards qualifiers "
3757                                         "from pointer target type"),
3758                                      G_("initialization discards qualifiers "
3759                                         "from pointer target type"),
3760                                      G_("return discards qualifiers from "
3761                                         "pointer target type"));
3762             }
3763
3764           if (pedantic && !DECL_IN_SYSTEM_HEADER (fundecl))
3765             pedwarn ("ISO C prohibits argument conversion to union type");
3766
3767           return build1 (NOP_EXPR, type, rhs);
3768         }
3769     }
3770
3771   /* Conversions among pointers */
3772   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3773            && (coder == codel))
3774     {
3775       tree ttl = TREE_TYPE (type);
3776       tree ttr = TREE_TYPE (rhstype);
3777       tree mvl = ttl;
3778       tree mvr = ttr;
3779       bool is_opaque_pointer;
3780       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3781
3782       if (TREE_CODE (mvl) != ARRAY_TYPE)
3783         mvl = TYPE_MAIN_VARIANT (mvl);
3784       if (TREE_CODE (mvr) != ARRAY_TYPE)
3785         mvr = TYPE_MAIN_VARIANT (mvr);
3786       /* Opaque pointers are treated like void pointers.  */
3787       is_opaque_pointer = (targetm.vector_opaque_p (type)
3788                            || targetm.vector_opaque_p (rhstype))
3789         && TREE_CODE (ttl) == VECTOR_TYPE
3790         && TREE_CODE (ttr) == VECTOR_TYPE;
3791
3792       /* C++ does not allow the implicit conversion void* -> T*.  However,
3793          for the purpose of reducing the number of false positives, we
3794          tolerate the special case of
3795
3796                 int *p = NULL;
3797
3798          where NULL is typically defined in C to be '(void *) 0'.  */
3799       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3800         warning (OPT_Wc___compat, "request for implicit conversion from "
3801                  "%qT to %qT not permitted in C++", rhstype, type);
3802
3803       /* Check if the right-hand side has a format attribute but the
3804          left-hand side doesn't.  */
3805       if (warn_missing_format_attribute
3806           && check_missing_format_attribute (type, rhstype))
3807         {
3808           switch (errtype)
3809           {
3810           case ic_argpass:
3811           case ic_argpass_nonproto:
3812             warning (OPT_Wmissing_format_attribute,
3813                      "argument %d of %qE might be "
3814                      "a candidate for a format attribute",
3815                      parmnum, rname);
3816             break;
3817           case ic_assign:
3818             warning (OPT_Wmissing_format_attribute,
3819                      "assignment left-hand side might be "
3820                      "a candidate for a format attribute");
3821             break;
3822           case ic_init:
3823             warning (OPT_Wmissing_format_attribute,
3824                      "initialization left-hand side might be "
3825                      "a candidate for a format attribute");
3826             break;
3827           case ic_return:
3828             warning (OPT_Wmissing_format_attribute,
3829                      "return type might be "
3830                      "a candidate for a format attribute");
3831             break;
3832           default:
3833             gcc_unreachable ();
3834           }
3835         }
3836
3837       /* Any non-function converts to a [const][volatile] void *
3838          and vice versa; otherwise, targets must be the same.
3839          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3840       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3841           || (target_cmp = comp_target_types (type, rhstype))
3842           || is_opaque_pointer
3843           || (c_common_unsigned_type (mvl)
3844               == c_common_unsigned_type (mvr)))
3845         {
3846           if (pedantic
3847               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3848                   ||
3849                   (VOID_TYPE_P (ttr)
3850                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3851                       which are not ANSI null ptr constants.  */
3852                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3853                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3854             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3855                                     "%qE between function pointer "
3856                                     "and %<void *%>"),
3857                                  G_("ISO C forbids assignment between "
3858                                     "function pointer and %<void *%>"),
3859                                  G_("ISO C forbids initialization between "
3860                                     "function pointer and %<void *%>"),
3861                                  G_("ISO C forbids return between function "
3862                                     "pointer and %<void *%>"));
3863           /* Const and volatile mean something different for function types,
3864              so the usual warnings are not appropriate.  */
3865           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3866                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3867             {
3868               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3869                 {
3870                   /* Types differing only by the presence of the 'volatile'
3871                      qualifier are acceptable if the 'volatile' has been added
3872                      in by the Objective-C EH machinery.  */
3873                   if (!objc_type_quals_match (ttl, ttr))
3874                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3875                                             "qualifiers from pointer target type"),
3876                                          G_("assignment discards qualifiers "
3877                                             "from pointer target type"),
3878                                          G_("initialization discards qualifiers "
3879                                             "from pointer target type"),
3880                                          G_("return discards qualifiers from "
3881                                             "pointer target type"));
3882                 }
3883               /* If this is not a case of ignoring a mismatch in signedness,
3884                  no warning.  */
3885               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3886                        || target_cmp)
3887                 ;
3888               /* If there is a mismatch, do warn.  */
3889               else if (warn_pointer_sign)
3890                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
3891                                         "%d of %qE differ in signedness"),
3892                                      G_("pointer targets in assignment "
3893                                         "differ in signedness"),
3894                                      G_("pointer targets in initialization "
3895                                         "differ in signedness"),
3896                                      G_("pointer targets in return differ "
3897                                         "in signedness"));
3898             }
3899           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3900                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3901             {
3902               /* Because const and volatile on functions are restrictions
3903                  that say the function will not do certain things,
3904                  it is okay to use a const or volatile function
3905                  where an ordinary one is wanted, but not vice-versa.  */
3906               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3907                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3908                                         "qualified function pointer "
3909                                         "from unqualified"),
3910                                      G_("assignment makes qualified function "
3911                                         "pointer from unqualified"),
3912                                      G_("initialization makes qualified "
3913                                         "function pointer from unqualified"),
3914                                      G_("return makes qualified function "
3915                                         "pointer from unqualified"));
3916             }
3917         }
3918       else
3919         /* Avoid warning about the volatile ObjC EH puts on decls.  */
3920         if (!objc_ok)
3921           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
3922                                   "incompatible pointer type"),
3923                                G_("assignment from incompatible pointer type"),
3924                                G_("initialization from incompatible "
3925                                   "pointer type"),
3926                                G_("return from incompatible pointer type"));
3927
3928       return convert (type, rhs);
3929     }
3930   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3931     {
3932       /* ??? This should not be an error when inlining calls to
3933          unprototyped functions.  */
3934       error ("invalid use of non-lvalue array");
3935       return error_mark_node;
3936     }
3937   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3938     {
3939       /* An explicit constant 0 can convert to a pointer,
3940          or one that results from arithmetic, even including
3941          a cast to integer type.  */
3942       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3943           &&
3944           !(TREE_CODE (rhs) == NOP_EXPR
3945             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3946             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3947             && integer_zerop (TREE_OPERAND (rhs, 0))))
3948         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3949                                 "pointer from integer without a cast"),
3950                              G_("assignment makes pointer from integer "
3951                                 "without a cast"),
3952                              G_("initialization makes pointer from "
3953                                 "integer without a cast"),
3954                              G_("return makes pointer from integer "
3955                                 "without a cast"));
3956
3957       return convert (type, rhs);
3958     }
3959   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3960     {
3961       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
3962                               "from pointer without a cast"),
3963                            G_("assignment makes integer from pointer "
3964                               "without a cast"),
3965                            G_("initialization makes integer from pointer "
3966                               "without a cast"),
3967                            G_("return makes integer from pointer "
3968                               "without a cast"));
3969       return convert (type, rhs);
3970     }
3971   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3972     return convert (type, rhs);
3973
3974   switch (errtype)
3975     {
3976     case ic_argpass:
3977     case ic_argpass_nonproto:
3978       /* ??? This should not be an error when inlining calls to
3979          unprototyped functions.  */
3980       error ("incompatible type for argument %d of %qE", parmnum, rname);
3981       break;
3982     case ic_assign:
3983       error ("incompatible types in assignment");
3984       break;
3985     case ic_init:
3986       error ("incompatible types in initialization");
3987       break;
3988     case ic_return:
3989       error ("incompatible types in return");
3990       break;
3991     default:
3992       gcc_unreachable ();
3993     }
3994
3995   return error_mark_node;
3996 }
3997
3998 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
3999    is used for error and waring reporting and indicates which argument
4000    is being processed.  */
4001
4002 tree
4003 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4004 {
4005   tree ret, type;
4006
4007   /* If FN was prototyped, the value has been converted already
4008      in convert_arguments.  */
4009   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4010     return value;
4011
4012   type = TREE_TYPE (parm);
4013   ret = convert_for_assignment (type, value,
4014                                 ic_argpass_nonproto, fn,
4015                                 fn, argnum);
4016   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4017       && INTEGRAL_TYPE_P (type)
4018       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4019     ret = default_conversion (ret);
4020   return ret;
4021 }
4022 \f
4023 /* If VALUE is a compound expr all of whose expressions are constant, then
4024    return its value.  Otherwise, return error_mark_node.
4025
4026    This is for handling COMPOUND_EXPRs as initializer elements
4027    which is allowed with a warning when -pedantic is specified.  */
4028
4029 static tree
4030 valid_compound_expr_initializer (tree value, tree endtype)
4031 {
4032   if (TREE_CODE (value) == COMPOUND_EXPR)
4033     {
4034       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4035           == error_mark_node)
4036         return error_mark_node;
4037       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4038                                               endtype);
4039     }
4040   else if (!initializer_constant_valid_p (value, endtype))
4041     return error_mark_node;
4042   else
4043     return value;
4044 }
4045 \f
4046 /* Perform appropriate conversions on the initial value of a variable,
4047    store it in the declaration DECL,
4048    and print any error messages that are appropriate.
4049    If the init is invalid, store an ERROR_MARK.  */
4050
4051 void
4052 store_init_value (tree decl, tree init)
4053 {
4054   tree value, type;
4055
4056   /* If variable's type was invalidly declared, just ignore it.  */
4057
4058   type = TREE_TYPE (decl);
4059   if (TREE_CODE (type) == ERROR_MARK)
4060     return;
4061
4062   /* Digest the specified initializer into an expression.  */
4063
4064   value = digest_init (type, init, true, TREE_STATIC (decl));
4065
4066   /* Store the expression if valid; else report error.  */
4067
4068   if (!in_system_header
4069       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4070     warning (OPT_Wtraditional, "traditional C rejects automatic "
4071              "aggregate initialization");
4072
4073   DECL_INITIAL (decl) = value;
4074
4075   /* ANSI wants warnings about out-of-range constant initializers.  */
4076   STRIP_TYPE_NOPS (value);
4077   constant_expression_warning (value);
4078
4079   /* Check if we need to set array size from compound literal size.  */
4080   if (TREE_CODE (type) == ARRAY_TYPE
4081       && TYPE_DOMAIN (type) == 0
4082       && value != error_mark_node)
4083     {
4084       tree inside_init = init;
4085
4086       STRIP_TYPE_NOPS (inside_init);
4087       inside_init = fold (inside_init);
4088
4089       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4090         {
4091           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4092
4093           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4094             {
4095               /* For int foo[] = (int [3]){1}; we need to set array size
4096                  now since later on array initializer will be just the
4097                  brace enclosed list of the compound literal.  */
4098               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4099               layout_type (type);
4100               layout_decl (decl, 0);
4101             }
4102         }
4103     }
4104 }
4105 \f
4106 /* Methods for storing and printing names for error messages.  */
4107
4108 /* Implement a spelling stack that allows components of a name to be pushed
4109    and popped.  Each element on the stack is this structure.  */
4110
4111 struct spelling
4112 {
4113   int kind;
4114   union
4115     {
4116       int i;
4117       const char *s;
4118     } u;
4119 };
4120
4121 #define SPELLING_STRING 1
4122 #define SPELLING_MEMBER 2
4123 #define SPELLING_BOUNDS 3
4124
4125 static struct spelling *spelling;       /* Next stack element (unused).  */
4126 static struct spelling *spelling_base;  /* Spelling stack base.  */
4127 static int spelling_size;               /* Size of the spelling stack.  */
4128
4129 /* Macros to save and restore the spelling stack around push_... functions.
4130    Alternative to SAVE_SPELLING_STACK.  */
4131
4132 #define SPELLING_DEPTH() (spelling - spelling_base)
4133 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4134
4135 /* Push an element on the spelling stack with type KIND and assign VALUE
4136    to MEMBER.  */
4137
4138 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4139 {                                                                       \
4140   int depth = SPELLING_DEPTH ();                                        \
4141                                                                         \
4142   if (depth >= spelling_size)                                           \
4143     {                                                                   \
4144       spelling_size += 10;                                              \
4145       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4146                                   spelling_size);                       \
4147       RESTORE_SPELLING_DEPTH (depth);                                   \
4148     }                                                                   \
4149                                                                         \
4150   spelling->kind = (KIND);                                              \
4151   spelling->MEMBER = (VALUE);                                           \
4152   spelling++;                                                           \
4153 }
4154
4155 /* Push STRING on the stack.  Printed literally.  */
4156
4157 static void
4158 push_string (const char *string)
4159 {
4160   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4161 }
4162
4163 /* Push a member name on the stack.  Printed as '.' STRING.  */
4164
4165 static void
4166 push_member_name (tree decl)
4167 {
4168   const char *const string
4169     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4170   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4171 }
4172
4173 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4174
4175 static void
4176 push_array_bounds (int bounds)
4177 {
4178   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4179 }
4180
4181 /* Compute the maximum size in bytes of the printed spelling.  */
4182
4183 static int
4184 spelling_length (void)
4185 {
4186   int size = 0;
4187   struct spelling *p;
4188
4189   for (p = spelling_base; p < spelling; p++)
4190     {
4191       if (p->kind == SPELLING_BOUNDS)
4192         size += 25;
4193       else
4194         size += strlen (p->u.s) + 1;
4195     }
4196
4197   return size;
4198 }
4199
4200 /* Print the spelling to BUFFER and return it.  */
4201
4202 static char *
4203 print_spelling (char *buffer)
4204 {
4205   char *d = buffer;
4206   struct spelling *p;
4207
4208   for (p = spelling_base; p < spelling; p++)
4209     if (p->kind == SPELLING_BOUNDS)
4210       {
4211         sprintf (d, "[%d]", p->u.i);
4212         d += strlen (d);
4213       }
4214     else
4215       {
4216         const char *s;
4217         if (p->kind == SPELLING_MEMBER)
4218           *d++ = '.';
4219         for (s = p->u.s; (*d = *s++); d++)
4220           ;
4221       }
4222   *d++ = '\0';
4223   return buffer;
4224 }
4225
4226 /* Issue an error message for a bad initializer component.
4227    MSGID identifies the message.
4228    The component name is taken from the spelling stack.  */
4229
4230 void
4231 error_init (const char *msgid)
4232 {
4233   char *ofwhat;
4234
4235   error ("%s", _(msgid));
4236   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4237   if (*ofwhat)
4238     error ("(near initialization for %qs)", ofwhat);
4239 }
4240
4241 /* Issue a pedantic warning for a bad initializer component.
4242    MSGID identifies the message.
4243    The component name is taken from the spelling stack.  */
4244
4245 void
4246 pedwarn_init (const char *msgid)
4247 {
4248   char *ofwhat;
4249
4250   pedwarn ("%s", _(msgid));
4251   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4252   if (*ofwhat)
4253     pedwarn ("(near initialization for %qs)", ofwhat);
4254 }
4255
4256 /* Issue a warning for a bad initializer component.
4257    MSGID identifies the message.
4258    The component name is taken from the spelling stack.  */
4259
4260 static void
4261 warning_init (const char *msgid)
4262 {
4263   char *ofwhat;
4264
4265   warning (0, "%s", _(msgid));
4266   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4267   if (*ofwhat)
4268     warning (0, "(near initialization for %qs)", ofwhat);
4269 }
4270 \f
4271 /* If TYPE is an array type and EXPR is a parenthesized string
4272    constant, warn if pedantic that EXPR is being used to initialize an
4273    object of type TYPE.  */
4274
4275 void
4276 maybe_warn_string_init (tree type, struct c_expr expr)
4277 {
4278   if (pedantic
4279       && TREE_CODE (type) == ARRAY_TYPE
4280       && TREE_CODE (expr.value) == STRING_CST
4281       && expr.original_code != STRING_CST)
4282     pedwarn_init ("array initialized from parenthesized string constant");
4283 }
4284
4285 /* Digest the parser output INIT as an initializer for type TYPE.
4286    Return a C expression of type TYPE to represent the initial value.
4287
4288    If INIT is a string constant, STRICT_STRING is true if it is
4289    unparenthesized or we should not warn here for it being parenthesized.
4290    For other types of INIT, STRICT_STRING is not used.
4291
4292    REQUIRE_CONSTANT requests an error if non-constant initializers or
4293    elements are seen.  */
4294
4295 static tree
4296 digest_init (tree type, tree init, bool strict_string, int require_constant)
4297 {
4298   enum tree_code code = TREE_CODE (type);
4299   tree inside_init = init;
4300
4301   if (type == error_mark_node
4302       || init == error_mark_node
4303       || TREE_TYPE (init) == error_mark_node)
4304     return error_mark_node;
4305
4306   STRIP_TYPE_NOPS (inside_init);
4307
4308   inside_init = fold (inside_init);
4309
4310   /* Initialization of an array of chars from a string constant
4311      optionally enclosed in braces.  */
4312
4313   if (code == ARRAY_TYPE && inside_init
4314       && TREE_CODE (inside_init) == STRING_CST)
4315     {
4316       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4317       /* Note that an array could be both an array of character type
4318          and an array of wchar_t if wchar_t is signed char or unsigned
4319          char.  */
4320       bool char_array = (typ1 == char_type_node
4321                          || typ1 == signed_char_type_node
4322                          || typ1 == unsigned_char_type_node);
4323       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4324       if (char_array || wchar_array)
4325         {
4326           struct c_expr expr;
4327           bool char_string;
4328           expr.value = inside_init;
4329           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4330           maybe_warn_string_init (type, expr);
4331
4332           char_string
4333             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4334                == char_type_node);
4335
4336           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4337                          TYPE_MAIN_VARIANT (type)))
4338             return inside_init;
4339
4340           if (!wchar_array && !char_string)
4341             {
4342               error_init ("char-array initialized from wide string");
4343               return error_mark_node;
4344             }
4345           if (char_string && !char_array)
4346             {
4347               error_init ("wchar_t-array initialized from non-wide string");
4348               return error_mark_node;
4349             }
4350
4351           TREE_TYPE (inside_init) = type;
4352           if (TYPE_DOMAIN (type) != 0
4353               && TYPE_SIZE (type) != 0
4354               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4355               /* Subtract 1 (or sizeof (wchar_t))
4356                  because it's ok to ignore the terminating null char
4357                  that is counted in the length of the constant.  */
4358               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4359                                        TREE_STRING_LENGTH (inside_init)
4360                                        - ((TYPE_PRECISION (typ1)
4361                                            != TYPE_PRECISION (char_type_node))
4362                                           ? (TYPE_PRECISION (wchar_type_node)
4363                                              / BITS_PER_UNIT)
4364                                           : 1)))
4365             pedwarn_init ("initializer-string for array of chars is too long");
4366
4367           return inside_init;
4368         }
4369       else if (INTEGRAL_TYPE_P (typ1))
4370         {
4371           error_init ("array of inappropriate type initialized "
4372                       "from string constant");
4373           return error_mark_node;
4374         }
4375     }
4376
4377   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4378      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4379      below and handle as a constructor.  */
4380   if (code == VECTOR_TYPE
4381       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4382       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4383       && TREE_CONSTANT (inside_init))
4384     {
4385       if (TREE_CODE (inside_init) == VECTOR_CST
4386           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4387                         TYPE_MAIN_VARIANT (type)))
4388         return inside_init;
4389
4390       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4391         {
4392           unsigned HOST_WIDE_INT ix;
4393           tree value;
4394           bool constant_p = true;
4395
4396           /* Iterate through elements and check if all constructor
4397              elements are *_CSTs.  */
4398           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4399             if (!CONSTANT_CLASS_P (value))
4400               {
4401                 constant_p = false;
4402                 break;
4403               }
4404
4405           if (constant_p)
4406             return build_vector_from_ctor (type,
4407                                            CONSTRUCTOR_ELTS (inside_init));
4408         }
4409     }
4410
4411   /* Any type can be initialized
4412      from an expression of the same type, optionally with braces.  */
4413
4414   if (inside_init && TREE_TYPE (inside_init) != 0
4415       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4416                      TYPE_MAIN_VARIANT (type))
4417           || (code == ARRAY_TYPE
4418               && comptypes (TREE_TYPE (inside_init), type))
4419           || (code == VECTOR_TYPE
4420               && comptypes (TREE_TYPE (inside_init), type))
4421           || (code == POINTER_TYPE
4422               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4423               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4424                             TREE_TYPE (type)))))
4425     {
4426       if (code == POINTER_TYPE)
4427         {
4428           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4429             {
4430               if (TREE_CODE (inside_init) == STRING_CST
4431                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4432                 inside_init = array_to_pointer_conversion (inside_init);
4433               else
4434                 {
4435                   error_init ("invalid use of non-lvalue array");
4436                   return error_mark_node;
4437                 }
4438             }
4439         }
4440
4441       if (code == VECTOR_TYPE)
4442         /* Although the types are compatible, we may require a
4443            conversion.  */
4444         inside_init = convert (type, inside_init);
4445
4446       if (require_constant && !flag_isoc99
4447           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4448         {
4449           /* As an extension, allow initializing objects with static storage
4450              duration with compound literals (which are then treated just as
4451              the brace enclosed list they contain).  */
4452           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4453           inside_init = DECL_INITIAL (decl);
4454         }
4455
4456       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4457           && TREE_CODE (inside_init) != CONSTRUCTOR)
4458         {
4459           error_init ("array initialized from non-constant array expression");
4460           return error_mark_node;
4461         }
4462
4463       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4464         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4465
4466       /* Compound expressions can only occur here if -pedantic or
4467          -pedantic-errors is specified.  In the later case, we always want
4468          an error.  In the former case, we simply want a warning.  */
4469       if (require_constant && pedantic
4470           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4471         {
4472           inside_init
4473             = valid_compound_expr_initializer (inside_init,
4474                                                TREE_TYPE (inside_init));
4475           if (inside_init == error_mark_node)
4476             error_init ("initializer element is not constant");
4477           else
4478             pedwarn_init ("initializer element is not constant");
4479           if (flag_pedantic_errors)
4480             inside_init = error_mark_node;
4481         }
4482       else if (require_constant
4483                && !initializer_constant_valid_p (inside_init,
4484                                                  TREE_TYPE (inside_init)))
4485         {
4486           error_init ("initializer element is not constant");
4487           inside_init = error_mark_node;
4488         }
4489
4490       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4491       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4492         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4493                                               NULL_TREE, 0);
4494       return inside_init;
4495     }
4496
4497   /* Handle scalar types, including conversions.  */
4498
4499   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4500       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4501       || code == VECTOR_TYPE)
4502     {
4503       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4504           && (TREE_CODE (init) == STRING_CST
4505               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4506         init = array_to_pointer_conversion (init);
4507       inside_init
4508         = convert_for_assignment (type, init, ic_init,
4509                                   NULL_TREE, NULL_TREE, 0);
4510
4511       /* Check to see if we have already given an error message.  */
4512       if (inside_init == error_mark_node)
4513         ;
4514       else if (require_constant && !TREE_CONSTANT (inside_init))
4515         {
4516           error_init ("initializer element is not constant");
4517           inside_init = error_mark_node;
4518         }
4519       else if (require_constant
4520                && !initializer_constant_valid_p (inside_init,
4521                                                  TREE_TYPE (inside_init)))
4522         {
4523           error_init ("initializer element is not computable at load time");
4524           inside_init = error_mark_node;
4525         }
4526
4527       return inside_init;
4528     }
4529
4530   /* Come here only for records and arrays.  */
4531
4532   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4533     {
4534       error_init ("variable-sized object may not be initialized");
4535       return error_mark_node;
4536     }
4537
4538   error_init ("invalid initializer");
4539   return error_mark_node;
4540 }
4541 \f
4542 /* Handle initializers that use braces.  */
4543
4544 /* Type of object we are accumulating a constructor for.
4545    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4546 static tree constructor_type;
4547
4548 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4549    left to fill.  */
4550 static tree constructor_fields;
4551
4552 /* For an ARRAY_TYPE, this is the specified index
4553    at which to store the next element we get.  */
4554 static tree constructor_index;
4555
4556 /* For an ARRAY_TYPE, this is the maximum index.  */
4557 static tree constructor_max_index;
4558
4559 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4560 static tree constructor_unfilled_fields;
4561
4562 /* For an ARRAY_TYPE, this is the index of the first element
4563    not yet written out.  */
4564 static tree constructor_unfilled_index;
4565
4566 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4567    This is so we can generate gaps between fields, when appropriate.  */
4568 static tree constructor_bit_index;
4569
4570 /* If we are saving up the elements rather than allocating them,
4571    this is the list of elements so far (in reverse order,
4572    most recent first).  */
4573 static VEC(constructor_elt,gc) *constructor_elements;
4574
4575 /* 1 if constructor should be incrementally stored into a constructor chain,
4576    0 if all the elements should be kept in AVL tree.  */
4577 static int constructor_incremental;
4578
4579 /* 1 if so far this constructor's elements are all compile-time constants.  */
4580 static int constructor_constant;
4581
4582 /* 1 if so far this constructor's elements are all valid address constants.  */
4583 static int constructor_simple;
4584
4585 /* 1 if this constructor is erroneous so far.  */
4586 static int constructor_erroneous;
4587
4588 /* Structure for managing pending initializer elements, organized as an
4589    AVL tree.  */
4590
4591 struct init_node
4592 {
4593   struct init_node *left, *right;
4594   struct init_node *parent;
4595   int balance;
4596   tree purpose;
4597   tree value;
4598 };
4599
4600 /* Tree of pending elements at this constructor level.
4601    These are elements encountered out of order
4602    which belong at places we haven't reached yet in actually
4603    writing the output.
4604    Will never hold tree nodes across GC runs.  */
4605 static struct init_node *constructor_pending_elts;
4606
4607 /* The SPELLING_DEPTH of this constructor.  */
4608 static int constructor_depth;
4609
4610 /* DECL node for which an initializer is being read.
4611    0 means we are reading a constructor expression
4612    such as (struct foo) {...}.  */
4613 static tree constructor_decl;
4614
4615 /* Nonzero if this is an initializer for a top-level decl.  */
4616 static int constructor_top_level;
4617
4618 /* Nonzero if there were any member designators in this initializer.  */
4619 static int constructor_designated;
4620
4621 /* Nesting depth of designator list.  */
4622 static int designator_depth;
4623
4624 /* Nonzero if there were diagnosed errors in this designator list.  */
4625 static int designator_errorneous;
4626
4627 \f
4628 /* This stack has a level for each implicit or explicit level of
4629    structuring in the initializer, including the outermost one.  It
4630    saves the values of most of the variables above.  */
4631
4632 struct constructor_range_stack;
4633
4634 struct constructor_stack
4635 {
4636   struct constructor_stack *next;
4637   tree type;
4638   tree fields;
4639   tree index;
4640   tree max_index;
4641   tree unfilled_index;
4642   tree unfilled_fields;
4643   tree bit_index;
4644   VEC(constructor_elt,gc) *elements;
4645   struct init_node *pending_elts;
4646   int offset;
4647   int depth;
4648   /* If value nonzero, this value should replace the entire
4649      constructor at this level.  */
4650   struct c_expr replacement_value;
4651   struct constructor_range_stack *range_stack;
4652   char constant;
4653   char simple;
4654   char implicit;
4655   char erroneous;
4656   char outer;
4657   char incremental;
4658   char designated;
4659 };
4660
4661 static struct constructor_stack *constructor_stack;
4662
4663 /* This stack represents designators from some range designator up to
4664    the last designator in the list.  */
4665
4666 struct constructor_range_stack
4667 {
4668   struct constructor_range_stack *next, *prev;
4669   struct constructor_stack *stack;
4670   tree range_start;
4671   tree index;
4672   tree range_end;
4673   tree fields;
4674 };
4675
4676 static struct constructor_range_stack *constructor_range_stack;
4677
4678 /* This stack records separate initializers that are nested.
4679    Nested initializers can't happen in ANSI C, but GNU C allows them
4680    in cases like { ... (struct foo) { ... } ... }.  */
4681
4682 struct initializer_stack
4683 {
4684   struct initializer_stack *next;
4685   tree decl;
4686   struct constructor_stack *constructor_stack;
4687   struct constructor_range_stack *constructor_range_stack;
4688   VEC(constructor_elt,gc) *elements;
4689   struct spelling *spelling;
4690   struct spelling *spelling_base;
4691   int spelling_size;
4692   char top_level;
4693   char require_constant_value;
4694   char require_constant_elements;
4695 };
4696
4697 static struct initializer_stack *initializer_stack;
4698 \f
4699 /* Prepare to parse and output the initializer for variable DECL.  */
4700
4701 void
4702 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4703 {
4704   const char *locus;
4705   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4706
4707   p->decl = constructor_decl;
4708   p->require_constant_value = require_constant_value;
4709   p->require_constant_elements = require_constant_elements;
4710   p->constructor_stack = constructor_stack;
4711   p->constructor_range_stack = constructor_range_stack;
4712   p->elements = constructor_elements;
4713   p->spelling = spelling;
4714   p->spelling_base = spelling_base;
4715   p->spelling_size = spelling_size;
4716   p->top_level = constructor_top_level;
4717   p->next = initializer_stack;
4718   initializer_stack = p;
4719
4720   constructor_decl = decl;
4721   constructor_designated = 0;
4722   constructor_top_level = top_level;
4723
4724   if (decl != 0 && decl != error_mark_node)
4725     {
4726       require_constant_value = TREE_STATIC (decl);
4727       require_constant_elements
4728         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4729            /* For a scalar, you can always use any value to initialize,
4730               even within braces.  */
4731            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4732                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4733                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4734                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4735       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4736     }
4737   else
4738     {
4739       require_constant_value = 0;
4740       require_constant_elements = 0;
4741       locus = "(anonymous)";
4742     }
4743
4744   constructor_stack = 0;
4745   constructor_range_stack = 0;
4746
4747   missing_braces_mentioned = 0;
4748
4749   spelling_base = 0;
4750   spelling_size = 0;
4751   RESTORE_SPELLING_DEPTH (0);
4752
4753   if (locus)
4754     push_string (locus);
4755 }
4756
4757 void
4758 finish_init (void)
4759 {
4760   struct initializer_stack *p = initializer_stack;
4761
4762   /* Free the whole constructor stack of this initializer.  */
4763   while (constructor_stack)
4764     {
4765       struct constructor_stack *q = constructor_stack;
4766       constructor_stack = q->next;
4767       free (q);
4768     }
4769
4770   gcc_assert (!constructor_range_stack);
4771
4772   /* Pop back to the data of the outer initializer (if any).  */
4773   free (spelling_base);
4774
4775   constructor_decl = p->decl;
4776   require_constant_value = p->require_constant_value;
4777   require_constant_elements = p->require_constant_elements;
4778   constructor_stack = p->constructor_stack;
4779   constructor_range_stack = p->constructor_range_stack;
4780   constructor_elements = p->elements;
4781   spelling = p->spelling;
4782   spelling_base = p->spelling_base;
4783   spelling_size = p->spelling_size;
4784   constructor_top_level = p->top_level;
4785   initializer_stack = p->next;
4786   free (p);
4787 }
4788 \f
4789 /* Call here when we see the initializer is surrounded by braces.
4790    This is instead of a call to push_init_level;
4791    it is matched by a call to pop_init_level.
4792
4793    TYPE is the type to initialize, for a constructor expression.
4794    For an initializer for a decl, TYPE is zero.  */
4795
4796 void
4797 really_start_incremental_init (tree type)
4798 {
4799   struct constructor_stack *p = XNEW (struct constructor_stack);
4800
4801   if (type == 0)
4802     type = TREE_TYPE (constructor_decl);
4803
4804   if (targetm.vector_opaque_p (type))
4805     error ("opaque vector types cannot be initialized");
4806
4807   p->type = constructor_type;
4808   p->fields = constructor_fields;
4809   p->index = constructor_index;
4810   p->max_index = constructor_max_index;
4811   p->unfilled_index = constructor_unfilled_index;
4812   p->unfilled_fields = constructor_unfilled_fields;
4813   p->bit_index = constructor_bit_index;
4814   p->elements = constructor_elements;
4815   p->constant = constructor_constant;
4816   p->simple = constructor_simple;
4817   p->erroneous = constructor_erroneous;
4818   p->pending_elts = constructor_pending_elts;
4819   p->depth = constructor_depth;
4820   p->replacement_value.value = 0;
4821   p->replacement_value.original_code = ERROR_MARK;
4822   p->implicit = 0;
4823   p->range_stack = 0;
4824   p->outer = 0;
4825   p->incremental = constructor_incremental;
4826   p->designated = constructor_designated;
4827   p->next = 0;
4828   constructor_stack = p;
4829
4830   constructor_constant = 1;
4831   constructor_simple = 1;
4832   constructor_depth = SPELLING_DEPTH ();
4833   constructor_elements = 0;
4834   constructor_pending_elts = 0;
4835   constructor_type = type;
4836   constructor_incremental = 1;
4837   constructor_designated = 0;
4838   designator_depth = 0;
4839   designator_errorneous = 0;
4840
4841   if (TREE_CODE (constructor_type) == RECORD_TYPE
4842       || TREE_CODE (constructor_type) == UNION_TYPE)
4843     {
4844       constructor_fields = TYPE_FIELDS (constructor_type);
4845       /* Skip any nameless bit fields at the beginning.  */
4846       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4847              && DECL_NAME (constructor_fields) == 0)
4848         constructor_fields = TREE_CHAIN (constructor_fields);
4849
4850       constructor_unfilled_fields = constructor_fields;
4851       constructor_bit_index = bitsize_zero_node;
4852     }
4853   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4854     {
4855       if (TYPE_DOMAIN (constructor_type))
4856         {
4857           constructor_max_index
4858             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4859
4860           /* Detect non-empty initializations of zero-length arrays.  */
4861           if (constructor_max_index == NULL_TREE
4862               && TYPE_SIZE (constructor_type))
4863             constructor_max_index = build_int_cst (NULL_TREE, -1);
4864
4865           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4866              to initialize VLAs will cause a proper error; avoid tree
4867              checking errors as well by setting a safe value.  */
4868           if (constructor_max_index
4869               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4870             constructor_max_index = build_int_cst (NULL_TREE, -1);
4871
4872           constructor_index
4873             = convert (bitsizetype,
4874                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4875         }
4876       else
4877         {
4878           constructor_index = bitsize_zero_node;
4879           constructor_max_index = NULL_TREE;
4880         }
4881
4882       constructor_unfilled_index = constructor_index;
4883     }
4884   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4885     {
4886       /* Vectors are like simple fixed-size arrays.  */
4887       constructor_max_index =
4888         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4889       constructor_index = convert (bitsizetype, bitsize_zero_node);
4890       constructor_unfilled_index = constructor_index;
4891     }
4892   else
4893     {
4894       /* Handle the case of int x = {5}; */
4895       constructor_fields = constructor_type;
4896       constructor_unfilled_fields = constructor_type;
4897     }
4898 }
4899 \f
4900 /* Push down into a subobject, for initialization.
4901    If this is for an explicit set of braces, IMPLICIT is 0.
4902    If it is because the next element belongs at a lower level,
4903    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4904
4905 void
4906 push_init_level (int implicit)
4907 {
4908   struct constructor_stack *p;
4909   tree value = NULL_TREE;
4910
4911   /* If we've exhausted any levels that didn't have braces,
4912      pop them now.  If implicit == 1, this will have been done in
4913      process_init_element; do not repeat it here because in the case
4914      of excess initializers for an empty aggregate this leads to an
4915      infinite cycle of popping a level and immediately recreating
4916      it.  */
4917   if (implicit != 1)
4918     {
4919       while (constructor_stack->implicit)
4920         {
4921           if ((TREE_CODE (constructor_type) == RECORD_TYPE
4922                || TREE_CODE (constructor_type) == UNION_TYPE)
4923               && constructor_fields == 0)
4924             process_init_element (pop_init_level (1));
4925           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4926                    && constructor_max_index
4927                    && tree_int_cst_lt (constructor_max_index,
4928                                        constructor_index))
4929             process_init_element (pop_init_level (1));
4930           else
4931             break;
4932         }
4933     }
4934
4935   /* Unless this is an explicit brace, we need to preserve previous
4936      content if any.  */
4937   if (implicit)
4938     {
4939       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4940            || TREE_CODE (constructor_type) == UNION_TYPE)
4941           && constructor_fields)
4942         value = find_init_member (constructor_fields);
4943       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4944         value = find_init_member (constructor_index);
4945     }
4946
4947   p = XNEW (struct constructor_stack);
4948   p->type = constructor_type;
4949   p->fields = constructor_fields;
4950   p->index = constructor_index;
4951   p->max_index = constructor_max_index;
4952   p->unfilled_index = constructor_unfilled_index;
4953   p->unfilled_fields = constructor_unfilled_fields;
4954   p->bit_index = constructor_bit_index;
4955   p->elements = constructor_elements;
4956   p->constant = constructor_constant;
4957   p->simple = constructor_simple;
4958   p->erroneous = constructor_erroneous;
4959   p->pending_elts = constructor_pending_elts;
4960   p->depth = constructor_depth;
4961   p->replacement_value.value = 0;
4962   p->replacement_value.original_code = ERROR_MARK;
4963   p->implicit = implicit;
4964   p->outer = 0;
4965   p->incremental = constructor_incremental;
4966   p->designated = constructor_designated;
4967   p->next = constructor_stack;
4968   p->range_stack = 0;
4969   constructor_stack = p;
4970
4971   constructor_constant = 1;
4972   constructor_simple = 1;
4973   constructor_depth = SPELLING_DEPTH ();
4974   constructor_elements = 0;
4975   constructor_incremental = 1;
4976   constructor_designated = 0;
4977   constructor_pending_elts = 0;
4978   if (!implicit)
4979     {
4980       p->range_stack = constructor_range_stack;
4981       constructor_range_stack = 0;
4982       designator_depth = 0;
4983       designator_errorneous = 0;
4984     }
4985
4986   /* Don't die if an entire brace-pair level is superfluous
4987      in the containing level.  */
4988   if (constructor_type == 0)
4989     ;
4990   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4991            || TREE_CODE (constructor_type) == UNION_TYPE)
4992     {
4993       /* Don't die if there are extra init elts at the end.  */
4994       if (constructor_fields == 0)
4995         constructor_type = 0;
4996       else
4997         {
4998           constructor_type = TREE_TYPE (constructor_fields);
4999           push_member_name (constructor_fields);
5000           constructor_depth++;
5001         }
5002     }
5003   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5004     {
5005       constructor_type = TREE_TYPE (constructor_type);
5006       push_array_bounds (tree_low_cst (constructor_index, 0));
5007       constructor_depth++;
5008     }
5009
5010   if (constructor_type == 0)
5011     {
5012       error_init ("extra brace group at end of initializer");
5013       constructor_fields = 0;
5014       constructor_unfilled_fields = 0;
5015       return;
5016     }
5017
5018   if (value && TREE_CODE (value) == CONSTRUCTOR)
5019     {
5020       constructor_constant = TREE_CONSTANT (value);
5021       constructor_simple = TREE_STATIC (value);
5022       constructor_elements = CONSTRUCTOR_ELTS (value);
5023       if (!VEC_empty (constructor_elt, constructor_elements)
5024           && (TREE_CODE (constructor_type) == RECORD_TYPE
5025               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5026         set_nonincremental_init ();
5027     }
5028
5029   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5030     {
5031       missing_braces_mentioned = 1;
5032       warning_init ("missing braces around initializer");
5033     }
5034
5035   if (TREE_CODE (constructor_type) == RECORD_TYPE
5036            || TREE_CODE (constructor_type) == UNION_TYPE)
5037     {
5038       constructor_fields = TYPE_FIELDS (constructor_type);
5039       /* Skip any nameless bit fields at the beginning.  */
5040       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5041              && DECL_NAME (constructor_fields) == 0)
5042         constructor_fields = TREE_CHAIN (constructor_fields);
5043
5044       constructor_unfilled_fields = constructor_fields;
5045       constructor_bit_index = bitsize_zero_node;
5046     }
5047   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5048     {
5049       /* Vectors are like simple fixed-size arrays.  */
5050       constructor_max_index =
5051         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5052       constructor_index = convert (bitsizetype, integer_zero_node);
5053       constructor_unfilled_index = constructor_index;
5054     }
5055   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5056     {
5057       if (TYPE_DOMAIN (constructor_type))
5058         {
5059           constructor_max_index
5060             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5061
5062           /* Detect non-empty initializations of zero-length arrays.  */
5063           if (constructor_max_index == NULL_TREE
5064               && TYPE_SIZE (constructor_type))
5065             constructor_max_index = build_int_cst (NULL_TREE, -1);
5066
5067           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5068              to initialize VLAs will cause a proper error; avoid tree
5069              checking errors as well by setting a safe value.  */
5070           if (constructor_max_index
5071               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5072             constructor_max_index = build_int_cst (NULL_TREE, -1);
5073
5074           constructor_index
5075             = convert (bitsizetype,
5076                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5077         }
5078       else
5079         constructor_index = bitsize_zero_node;
5080
5081       constructor_unfilled_index = constructor_index;
5082       if (value && TREE_CODE (value) == STRING_CST)
5083         {
5084           /* We need to split the char/wchar array into individual
5085              characters, so that we don't have to special case it
5086              everywhere.  */
5087           set_nonincremental_init_from_string (value);
5088         }
5089     }
5090   else
5091     {
5092       if (constructor_type != error_mark_node)
5093         warning_init ("braces around scalar initializer");
5094       constructor_fields = constructor_type;
5095       constructor_unfilled_fields = constructor_type;
5096     }
5097 }
5098
5099 /* At the end of an implicit or explicit brace level,
5100    finish up that level of constructor.  If a single expression
5101    with redundant braces initialized that level, return the
5102    c_expr structure for that expression.  Otherwise, the original_code
5103    element is set to ERROR_MARK.
5104    If we were outputting the elements as they are read, return 0 as the value
5105    from inner levels (process_init_element ignores that),
5106    but return error_mark_node as the value from the outermost level
5107    (that's what we want to put in DECL_INITIAL).
5108    Otherwise, return a CONSTRUCTOR expression as the value.  */
5109
5110 struct c_expr
5111 pop_init_level (int implicit)
5112 {
5113   struct constructor_stack *p;
5114   struct c_expr ret;
5115   ret.value = 0;
5116   ret.original_code = ERROR_MARK;
5117
5118   if (implicit == 0)
5119     {
5120       /* When we come to an explicit close brace,
5121          pop any inner levels that didn't have explicit braces.  */
5122       while (constructor_stack->implicit)
5123         process_init_element (pop_init_level (1));
5124
5125       gcc_assert (!constructor_range_stack);
5126     }
5127
5128   /* Now output all pending elements.  */
5129   constructor_incremental = 1;
5130   output_pending_init_elements (1);
5131
5132   p = constructor_stack;
5133
5134   /* Error for initializing a flexible array member, or a zero-length
5135      array member in an inappropriate context.  */
5136   if (constructor_type && constructor_fields
5137       && TREE_CODE (constructor_type) == ARRAY_TYPE
5138       && TYPE_DOMAIN (constructor_type)
5139       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5140     {
5141       /* Silently discard empty initializations.  The parser will
5142          already have pedwarned for empty brackets.  */
5143       if (integer_zerop (constructor_unfilled_index))
5144         constructor_type = NULL_TREE;
5145       else
5146         {
5147           gcc_assert (!TYPE_SIZE (constructor_type));
5148
5149           if (constructor_depth > 2)
5150             error_init ("initialization of flexible array member in a nested context");
5151           else if (pedantic)
5152             pedwarn_init ("initialization of a flexible array member");
5153
5154           /* We have already issued an error message for the existence
5155              of a flexible array member not at the end of the structure.
5156              Discard the initializer so that we do not die later.  */
5157           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5158             constructor_type = NULL_TREE;
5159         }
5160     }
5161
5162   /* Warn when some struct elements are implicitly initialized to zero.  */
5163   if (warn_missing_field_initializers
5164       && constructor_type
5165       && TREE_CODE (constructor_type) == RECORD_TYPE
5166       && constructor_unfilled_fields)
5167     {
5168         /* Do not warn for flexible array members or zero-length arrays.  */
5169         while (constructor_unfilled_fields
5170                && (!DECL_SIZE (constructor_unfilled_fields)
5171                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5172           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5173
5174         /* Do not warn if this level of the initializer uses member
5175            designators; it is likely to be deliberate.  */
5176         if (constructor_unfilled_fields && !constructor_designated)
5177           {
5178             push_member_name (constructor_unfilled_fields);
5179             warning_init ("missing initializer");
5180             RESTORE_SPELLING_DEPTH (constructor_depth);
5181           }
5182     }
5183
5184   /* Pad out the end of the structure.  */
5185   if (p->replacement_value.value)
5186     /* If this closes a superfluous brace pair,
5187        just pass out the element between them.  */
5188     ret = p->replacement_value;
5189   else if (constructor_type == 0)
5190     ;
5191   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5192            && TREE_CODE (constructor_type) != UNION_TYPE
5193            && TREE_CODE (constructor_type) != ARRAY_TYPE
5194            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5195     {
5196       /* A nonincremental scalar initializer--just return
5197          the element, after verifying there is just one.  */
5198       if (VEC_empty (constructor_elt,constructor_elements))
5199         {
5200           if (!constructor_erroneous)
5201             error_init ("empty scalar initializer");
5202           ret.value = error_mark_node;
5203         }
5204       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5205         {
5206           error_init ("extra elements in scalar initializer");
5207           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5208         }
5209       else
5210         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5211     }
5212   else
5213     {
5214       if (constructor_erroneous)
5215         ret.value = error_mark_node;
5216       else
5217         {
5218           ret.value = build_constructor (constructor_type,
5219                                          constructor_elements);
5220           if (constructor_constant)
5221             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5222           if (constructor_constant && constructor_simple)
5223             TREE_STATIC (ret.value) = 1;
5224         }
5225     }
5226
5227   constructor_type = p->type;
5228   constructor_fields = p->fields;
5229   constructor_index = p->index;
5230   constructor_max_index = p->max_index;
5231   constructor_unfilled_index = p->unfilled_index;
5232   constructor_unfilled_fields = p->unfilled_fields;
5233   constructor_bit_index = p->bit_index;
5234   constructor_elements = p->elements;
5235   constructor_constant = p->constant;
5236   constructor_simple = p->simple;
5237   constructor_erroneous = p->erroneous;
5238   constructor_incremental = p->incremental;
5239   constructor_designated = p->designated;
5240   constructor_pending_elts = p->pending_elts;
5241   constructor_depth = p->depth;
5242   if (!p->implicit)
5243     constructor_range_stack = p->range_stack;
5244   RESTORE_SPELLING_DEPTH (constructor_depth);
5245
5246   constructor_stack = p->next;
5247   free (p);
5248
5249   if (ret.value == 0)
5250     {
5251       if (constructor_stack == 0)
5252         {
5253           ret.value = error_mark_node;
5254           return ret;
5255         }
5256       return ret;
5257     }
5258   return ret;
5259 }
5260
5261 /* Common handling for both array range and field name designators.
5262    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5263
5264 static int
5265 set_designator (int array)
5266 {
5267   tree subtype;
5268   enum tree_code subcode;
5269
5270   /* Don't die if an entire brace-pair level is superfluous
5271      in the containing level.  */
5272   if (constructor_type == 0)
5273     return 1;
5274
5275   /* If there were errors in this designator list already, bail out
5276      silently.  */
5277   if (designator_errorneous)
5278     return 1;
5279
5280   if (!designator_depth)
5281     {
5282       gcc_assert (!constructor_range_stack);
5283
5284       /* Designator list starts at the level of closest explicit
5285          braces.  */
5286       while (constructor_stack->implicit)
5287         process_init_element (pop_init_level (1));
5288       constructor_designated = 1;
5289       return 0;
5290     }
5291
5292   switch (TREE_CODE (constructor_type))
5293     {
5294     case  RECORD_TYPE:
5295     case  UNION_TYPE:
5296       subtype = TREE_TYPE (constructor_fields);
5297       if (subtype != error_mark_node)
5298         subtype = TYPE_MAIN_VARIANT (subtype);
5299       break;
5300     case ARRAY_TYPE:
5301       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5302       break;
5303     default:
5304       gcc_unreachable ();
5305     }
5306
5307   subcode = TREE_CODE (subtype);
5308   if (array && subcode != ARRAY_TYPE)
5309     {
5310       error_init ("array index in non-array initializer");
5311       return 1;
5312     }
5313   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5314     {
5315       error_init ("field name not in record or union initializer");
5316       return 1;
5317     }
5318
5319   constructor_designated = 1;
5320   push_init_level (2);
5321   return 0;
5322 }
5323
5324 /* If there are range designators in designator list, push a new designator
5325    to constructor_range_stack.  RANGE_END is end of such stack range or
5326    NULL_TREE if there is no range designator at this level.  */
5327
5328 static void
5329 push_range_stack (tree range_end)
5330 {
5331   struct constructor_range_stack *p;
5332
5333   p = GGC_NEW (struct constructor_range_stack);
5334   p->prev = constructor_range_stack;
5335   p->next = 0;
5336   p->fields = constructor_fields;
5337   p->range_start = constructor_index;
5338   p->index = constructor_index;
5339   p->stack = constructor_stack;
5340   p->range_end = range_end;
5341   if (constructor_range_stack)
5342     constructor_range_stack->next = p;
5343   constructor_range_stack = p;
5344 }
5345
5346 /* Within an array initializer, specify the next index to be initialized.
5347    FIRST is that index.  If LAST is nonzero, then initialize a range
5348    of indices, running from FIRST through LAST.  */
5349
5350 void
5351 set_init_index (tree first, tree last)
5352 {
5353   if (set_designator (1))
5354     return;
5355
5356   designator_errorneous = 1;
5357
5358   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5359       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5360     {
5361       error_init ("array index in initializer not of integer type");
5362       return;
5363     }
5364
5365   if (TREE_CODE (first) != INTEGER_CST)
5366     error_init ("nonconstant array index in initializer");
5367   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5368     error_init ("nonconstant array index in initializer");
5369   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5370     error_init ("array index in non-array initializer");
5371   else if (tree_int_cst_sgn (first) == -1)
5372     error_init ("array index in initializer exceeds array bounds");
5373   else if (constructor_max_index
5374            && tree_int_cst_lt (constructor_max_index, first))
5375     error_init ("array index in initializer exceeds array bounds");
5376   else
5377     {
5378       constructor_index = convert (bitsizetype, first);
5379
5380       if (last)
5381         {
5382           if (tree_int_cst_equal (first, last))
5383             last = 0;
5384           else if (tree_int_cst_lt (last, first))
5385             {
5386               error_init ("empty index range in initializer");
5387               last = 0;
5388             }
5389           else
5390             {
5391               last = convert (bitsizetype, last);
5392               if (constructor_max_index != 0
5393                   && tree_int_cst_lt (constructor_max_index, last))
5394                 {
5395                   error_init ("array index range in initializer exceeds array bounds");
5396                   last = 0;
5397                 }
5398             }
5399         }
5400
5401       designator_depth++;
5402       designator_errorneous = 0;
5403       if (constructor_range_stack || last)
5404         push_range_stack (last);
5405     }
5406 }
5407
5408 /* Within a struct initializer, specify the next field to be initialized.  */
5409
5410 void
5411 set_init_label (tree fieldname)
5412 {
5413   tree tail;
5414
5415   if (set_designator (0))
5416     return;
5417
5418   designator_errorneous = 1;
5419
5420   if (TREE_CODE (constructor_type) != RECORD_TYPE
5421       && TREE_CODE (constructor_type) != UNION_TYPE)
5422     {
5423       error_init ("field name not in record or union initializer");
5424       return;
5425     }
5426
5427   for (tail = TYPE_FIELDS (constructor_type); tail;
5428        tail = TREE_CHAIN (tail))
5429     {
5430       if (DECL_NAME (tail) == fieldname)
5431         break;
5432     }
5433
5434   if (tail == 0)
5435     error ("unknown field %qE specified in initializer", fieldname);
5436   else
5437     {
5438       constructor_fields = tail;
5439       designator_depth++;
5440       designator_errorneous = 0;
5441       if (constructor_range_stack)
5442         push_range_stack (NULL_TREE);
5443     }
5444 }
5445 \f
5446 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5447    identifies the initializer, either array index or field in a structure.
5448    VALUE is the value of that index or field.  */
5449
5450 static void
5451 add_pending_init (tree purpose, tree value)
5452 {
5453   struct init_node *p, **q, *r;
5454
5455   q = &constructor_pending_elts;
5456   p = 0;
5457
5458   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5459     {
5460       while (*q != 0)
5461         {
5462           p = *q;
5463           if (tree_int_cst_lt (purpose, p->purpose))
5464             q = &p->left;
5465           else if (tree_int_cst_lt (p->purpose, purpose))
5466             q = &p->right;
5467           else
5468             {
5469               if (TREE_SIDE_EFFECTS (p->value))
5470                 warning_init ("initialized field with side-effects overwritten");
5471               p->value = value;
5472               return;
5473             }
5474         }
5475     }
5476   else
5477     {
5478       tree bitpos;
5479
5480       bitpos = bit_position (purpose);
5481       while (*q != NULL)
5482         {
5483           p = *q;
5484           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5485             q = &p->left;
5486           else if (p->purpose != purpose)
5487             q = &p->right;
5488           else
5489             {
5490               if (TREE_SIDE_EFFECTS (p->value))
5491                 warning_init ("initialized field with side-effects overwritten");
5492               p->value = value;
5493               return;
5494             }
5495         }
5496     }
5497
5498   r = GGC_NEW (struct init_node);
5499   r->purpose = purpose;
5500   r->value = value;
5501
5502   *q = r;
5503   r->parent = p;
5504   r->left = 0;
5505   r->right = 0;
5506   r->balance = 0;
5507
5508   while (p)
5509     {
5510       struct init_node *s;
5511
5512       if (r == p->left)
5513         {
5514           if (p->balance == 0)
5515             p->balance = -1;
5516           else if (p->balance < 0)
5517             {
5518               if (r->balance < 0)
5519                 {
5520                   /* L rotation.  */
5521                   p->left = r->right;
5522                   if (p->left)
5523                     p->left->parent = p;
5524                   r->right = p;
5525
5526                   p->balance = 0;
5527                   r->balance = 0;
5528
5529                   s = p->parent;
5530                   p->parent = r;
5531                   r->parent = s;
5532                   if (s)
5533                     {
5534                       if (s->left == p)
5535                         s->left = r;
5536                       else
5537                         s->right = r;
5538                     }
5539                   else
5540                     constructor_pending_elts = r;
5541                 }
5542               else
5543                 {
5544                   /* LR rotation.  */
5545                   struct init_node *t = r->right;
5546
5547                   r->right = t->left;
5548                   if (r->right)
5549                     r->right->parent = r;
5550                   t->left = r;
5551
5552                   p->left = t->right;
5553                   if (p->left)
5554                     p->left->parent = p;
5555                   t->right = p;
5556
5557                   p->balance = t->balance < 0;
5558                   r->balance = -(t->balance > 0);
5559                   t->balance = 0;
5560
5561                   s = p->parent;
5562                   p->parent = t;
5563                   r->parent = t;
5564                   t->parent = s;
5565                   if (s)
5566                     {
5567                       if (s->left == p)
5568                         s->left = t;
5569                       else
5570                         s->right = t;
5571                     }
5572                   else
5573                     constructor_pending_elts = t;
5574                 }
5575               break;
5576             }
5577           else
5578             {
5579               /* p->balance == +1; growth of left side balances the node.  */
5580               p->balance = 0;
5581               break;
5582             }
5583         }
5584       else /* r == p->right */
5585         {
5586           if (p->balance == 0)
5587             /* Growth propagation from right side.  */
5588             p->balance++;
5589           else if (p->balance > 0)
5590             {
5591               if (r->balance > 0)
5592                 {
5593                   /* R rotation.  */
5594                   p->right = r->left;
5595                   if (p->right)
5596                     p->right->parent = p;
5597                   r->left = p;
5598
5599                   p->balance = 0;
5600                   r->balance = 0;
5601
5602                   s = p->parent;
5603                   p->parent = r;
5604                   r->parent = s;
5605                   if (s)
5606                     {
5607                       if (s->left == p)
5608                         s->left = r;
5609                       else
5610                         s->right = r;
5611                     }
5612                   else
5613                     constructor_pending_elts = r;
5614                 }
5615               else /* r->balance == -1 */
5616                 {
5617                   /* RL rotation */
5618                   struct init_node *t = r->left;
5619
5620                   r->left = t->right;
5621                   if (r->left)
5622                     r->left->parent = r;
5623                   t->right = r;
5624
5625                   p->right = t->left;
5626                   if (p->right)
5627                     p->right->parent = p;
5628                   t->left = p;
5629
5630                   r->balance = (t->balance < 0);
5631                   p->balance = -(t->balance > 0);
5632                   t->balance = 0;
5633
5634                   s = p->parent;
5635                   p->parent = t;
5636                   r->parent = t;
5637                   t->parent = s;
5638                   if (s)
5639                     {
5640                       if (s->left == p)
5641                         s->left = t;
5642                       else
5643                         s->right = t;
5644                     }
5645                   else
5646                     constructor_pending_elts = t;
5647                 }
5648               break;
5649             }
5650           else
5651             {
5652               /* p->balance == -1; growth of right side balances the node.  */
5653               p->balance = 0;
5654               break;
5655             }
5656         }
5657
5658       r = p;
5659       p = p->parent;
5660     }
5661 }
5662
5663 /* Build AVL tree from a sorted chain.  */
5664
5665 static void
5666 set_nonincremental_init (void)
5667 {
5668   unsigned HOST_WIDE_INT ix;
5669   tree index, value;
5670
5671   if (TREE_CODE (constructor_type) != RECORD_TYPE
5672       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5673     return;
5674
5675   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5676     add_pending_init (index, value);
5677   constructor_elements = 0;
5678   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5679     {
5680       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5681       /* Skip any nameless bit fields at the beginning.  */
5682       while (constructor_unfilled_fields != 0
5683              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5684              && DECL_NAME (constructor_unfilled_fields) == 0)
5685         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5686
5687     }
5688   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5689     {
5690       if (TYPE_DOMAIN (constructor_type))
5691         constructor_unfilled_index
5692             = convert (bitsizetype,
5693                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5694       else
5695         constructor_unfilled_index = bitsize_zero_node;
5696     }
5697   constructor_incremental = 0;
5698 }
5699
5700 /* Build AVL tree from a string constant.  */
5701
5702 static void
5703 set_nonincremental_init_from_string (tree str)
5704 {
5705   tree value, purpose, type;
5706   HOST_WIDE_INT val[2];
5707   const char *p, *end;
5708   int byte, wchar_bytes, charwidth, bitpos;
5709
5710   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5711
5712   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5713       == TYPE_PRECISION (char_type_node))
5714     wchar_bytes = 1;
5715   else
5716     {
5717       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5718                   == TYPE_PRECISION (wchar_type_node));
5719       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5720     }
5721   charwidth = TYPE_PRECISION (char_type_node);
5722   type = TREE_TYPE (constructor_type);
5723   p = TREE_STRING_POINTER (str);
5724   end = p + TREE_STRING_LENGTH (str);
5725
5726   for (purpose = bitsize_zero_node;
5727        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5728        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5729     {
5730       if (wchar_bytes == 1)
5731         {
5732           val[1] = (unsigned char) *p++;
5733           val[0] = 0;
5734         }
5735       else
5736         {
5737           val[0] = 0;
5738           val[1] = 0;
5739           for (byte = 0; byte < wchar_bytes; byte++)
5740             {
5741               if (BYTES_BIG_ENDIAN)
5742                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5743               else
5744                 bitpos = byte * charwidth;
5745               val[bitpos < HOST_BITS_PER_WIDE_INT]
5746                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5747                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5748             }
5749         }
5750
5751       if (!TYPE_UNSIGNED (type))
5752         {
5753           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5754           if (bitpos < HOST_BITS_PER_WIDE_INT)
5755             {
5756               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5757                 {
5758                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5759                   val[0] = -1;
5760                 }
5761             }
5762           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5763             {
5764               if (val[1] < 0)
5765                 val[0] = -1;
5766             }
5767           else if (val[0] & (((HOST_WIDE_INT) 1)
5768                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5769             val[0] |= ((HOST_WIDE_INT) -1)
5770                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5771         }
5772
5773       value = build_int_cst_wide (type, val[1], val[0]);
5774       add_pending_init (purpose, value);
5775     }
5776
5777   constructor_incremental = 0;
5778 }
5779
5780 /* Return value of FIELD in pending initializer or zero if the field was
5781    not initialized yet.  */
5782
5783 static tree
5784 find_init_member (tree field)
5785 {
5786   struct init_node *p;
5787
5788   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5789     {
5790       if (constructor_incremental
5791           && tree_int_cst_lt (field, constructor_unfilled_index))
5792         set_nonincremental_init ();
5793
5794       p = constructor_pending_elts;
5795       while (p)
5796         {
5797           if (tree_int_cst_lt (field, p->purpose))
5798             p = p->left;
5799           else if (tree_int_cst_lt (p->purpose, field))
5800             p = p->right;
5801           else
5802             return p->value;
5803         }
5804     }
5805   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5806     {
5807       tree bitpos = bit_position (field);
5808
5809       if (constructor_incremental
5810           && (!constructor_unfilled_fields
5811               || tree_int_cst_lt (bitpos,
5812                                   bit_position (constructor_unfilled_fields))))
5813         set_nonincremental_init ();
5814
5815       p = constructor_pending_elts;
5816       while (p)
5817         {
5818           if (field == p->purpose)
5819             return p->value;
5820           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5821             p = p->left;
5822           else
5823             p = p->right;
5824         }
5825     }
5826   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5827     {
5828       if (!VEC_empty (constructor_elt, constructor_elements)
5829           && (VEC_last (constructor_elt, constructor_elements)->index
5830               == field))
5831         return VEC_last (constructor_elt, constructor_elements)->value;
5832     }
5833   return 0;
5834 }
5835
5836 /* "Output" the next constructor element.
5837    At top level, really output it to assembler code now.
5838    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5839    TYPE is the data type that the containing data type wants here.
5840    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5841    If VALUE is a string constant, STRICT_STRING is true if it is
5842    unparenthesized or we should not warn here for it being parenthesized.
5843    For other types of VALUE, STRICT_STRING is not used.
5844
5845    PENDING if non-nil means output pending elements that belong
5846    right after this element.  (PENDING is normally 1;
5847    it is 0 while outputting pending elements, to avoid recursion.)  */
5848
5849 static void
5850 output_init_element (tree value, bool strict_string, tree type, tree field,
5851                      int pending)
5852 {
5853   constructor_elt *celt;
5854
5855   if (type == error_mark_node || value == error_mark_node)
5856     {
5857       constructor_erroneous = 1;
5858       return;
5859     }
5860   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5861       && (TREE_CODE (value) == STRING_CST
5862           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5863       && !(TREE_CODE (value) == STRING_CST
5864            && TREE_CODE (type) == ARRAY_TYPE
5865            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5866       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5867                      TYPE_MAIN_VARIANT (type)))
5868     value = array_to_pointer_conversion (value);
5869
5870   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5871       && require_constant_value && !flag_isoc99 && pending)
5872     {
5873       /* As an extension, allow initializing objects with static storage
5874          duration with compound literals (which are then treated just as
5875          the brace enclosed list they contain).  */
5876       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5877       value = DECL_INITIAL (decl);
5878     }
5879
5880   if (value == error_mark_node)
5881     constructor_erroneous = 1;
5882   else if (!TREE_CONSTANT (value))
5883     constructor_constant = 0;
5884   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
5885            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5886                 || TREE_CODE (constructor_type) == UNION_TYPE)
5887                && DECL_C_BIT_FIELD (field)
5888                && TREE_CODE (value) != INTEGER_CST))
5889     constructor_simple = 0;
5890
5891   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
5892     {
5893       if (require_constant_value)
5894         {
5895           error_init ("initializer element is not constant");
5896           value = error_mark_node;
5897         }
5898       else if (require_constant_elements)
5899         pedwarn ("initializer element is not computable at load time");
5900     }
5901
5902   /* If this field is empty (and not at the end of structure),
5903      don't do anything other than checking the initializer.  */
5904   if (field
5905       && (TREE_TYPE (field) == error_mark_node
5906           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5907               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5908               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5909                   || TREE_CHAIN (field)))))
5910     return;
5911
5912   value = digest_init (type, value, strict_string, require_constant_value);
5913   if (value == error_mark_node)
5914     {
5915       constructor_erroneous = 1;
5916       return;
5917     }
5918
5919   /* If this element doesn't come next in sequence,
5920      put it on constructor_pending_elts.  */
5921   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5922       && (!constructor_incremental
5923           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5924     {
5925       if (constructor_incremental
5926           && tree_int_cst_lt (field, constructor_unfilled_index))
5927         set_nonincremental_init ();
5928
5929       add_pending_init (field, value);
5930       return;
5931     }
5932   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5933            && (!constructor_incremental
5934                || field != constructor_unfilled_fields))
5935     {
5936       /* We do this for records but not for unions.  In a union,
5937          no matter which field is specified, it can be initialized
5938          right away since it starts at the beginning of the union.  */
5939       if (constructor_incremental)
5940         {
5941           if (!constructor_unfilled_fields)
5942             set_nonincremental_init ();
5943           else
5944             {
5945               tree bitpos, unfillpos;
5946
5947               bitpos = bit_position (field);
5948               unfillpos = bit_position (constructor_unfilled_fields);
5949
5950               if (tree_int_cst_lt (bitpos, unfillpos))
5951                 set_nonincremental_init ();
5952             }
5953         }
5954
5955       add_pending_init (field, value);
5956       return;
5957     }
5958   else if (TREE_CODE (constructor_type) == UNION_TYPE
5959            && !VEC_empty (constructor_elt, constructor_elements))
5960     {
5961       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
5962                                        constructor_elements)->value))
5963         warning_init ("initialized field with side-effects overwritten");
5964
5965       /* We can have just one union field set.  */
5966       constructor_elements = 0;
5967     }
5968
5969   /* Otherwise, output this element either to
5970      constructor_elements or to the assembler file.  */
5971
5972   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
5973   celt->index = field;
5974   celt->value = value;
5975
5976   /* Advance the variable that indicates sequential elements output.  */
5977   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5978     constructor_unfilled_index
5979       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5980                     bitsize_one_node);
5981   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5982     {
5983       constructor_unfilled_fields
5984         = TREE_CHAIN (constructor_unfilled_fields);
5985
5986       /* Skip any nameless bit fields.  */
5987       while (constructor_unfilled_fields != 0
5988              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5989              && DECL_NAME (constructor_unfilled_fields) == 0)
5990         constructor_unfilled_fields =
5991           TREE_CHAIN (constructor_unfilled_fields);
5992     }
5993   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5994     constructor_unfilled_fields = 0;
5995
5996   /* Now output any pending elements which have become next.  */
5997   if (pending)
5998     output_pending_init_elements (0);
5999 }
6000
6001 /* Output any pending elements which have become next.
6002    As we output elements, constructor_unfilled_{fields,index}
6003    advances, which may cause other elements to become next;
6004    if so, they too are output.
6005
6006    If ALL is 0, we return when there are
6007    no more pending elements to output now.
6008
6009    If ALL is 1, we output space as necessary so that
6010    we can output all the pending elements.  */
6011
6012 static void
6013 output_pending_init_elements (int all)
6014 {
6015   struct init_node *elt = constructor_pending_elts;
6016   tree next;
6017
6018  retry:
6019
6020   /* Look through the whole pending tree.
6021      If we find an element that should be output now,
6022      output it.  Otherwise, set NEXT to the element
6023      that comes first among those still pending.  */
6024
6025   next = 0;
6026   while (elt)
6027     {
6028       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6029         {
6030           if (tree_int_cst_equal (elt->purpose,
6031                                   constructor_unfilled_index))
6032             output_init_element (elt->value, true,
6033                                  TREE_TYPE (constructor_type),
6034                                  constructor_unfilled_index, 0);
6035           else if (tree_int_cst_lt (constructor_unfilled_index,
6036                                     elt->purpose))
6037             {
6038               /* Advance to the next smaller node.  */
6039               if (elt->left)
6040                 elt = elt->left;
6041               else
6042                 {
6043                   /* We have reached the smallest node bigger than the
6044                      current unfilled index.  Fill the space first.  */
6045                   next = elt->purpose;
6046                   break;
6047                 }
6048             }
6049           else
6050             {
6051               /* Advance to the next bigger node.  */
6052               if (elt->right)
6053                 elt = elt->right;
6054               else
6055                 {
6056                   /* We have reached the biggest node in a subtree.  Find
6057                      the parent of it, which is the next bigger node.  */
6058                   while (elt->parent && elt->parent->right == elt)
6059                     elt = elt->parent;
6060                   elt = elt->parent;
6061                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6062                                               elt->purpose))
6063                     {
6064                       next = elt->purpose;
6065                       break;
6066                     }
6067                 }
6068             }
6069         }
6070       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6071                || TREE_CODE (constructor_type) == UNION_TYPE)
6072         {
6073           tree ctor_unfilled_bitpos, elt_bitpos;
6074
6075           /* If the current record is complete we are done.  */
6076           if (constructor_unfilled_fields == 0)
6077             break;
6078
6079           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6080           elt_bitpos = bit_position (elt->purpose);
6081           /* We can't compare fields here because there might be empty
6082              fields in between.  */
6083           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6084             {
6085               constructor_unfilled_fields = elt->purpose;
6086               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6087                                    elt->purpose, 0);
6088             }
6089           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6090             {
6091               /* Advance to the next smaller node.  */
6092               if (elt->left)
6093                 elt = elt->left;
6094               else
6095                 {
6096                   /* We have reached the smallest node bigger than the
6097                      current unfilled field.  Fill the space first.  */
6098                   next = elt->purpose;
6099                   break;
6100                 }
6101             }
6102           else
6103             {
6104               /* Advance to the next bigger node.  */
6105               if (elt->right)
6106                 elt = elt->right;
6107               else
6108                 {
6109                   /* We have reached the biggest node in a subtree.  Find
6110                      the parent of it, which is the next bigger node.  */
6111                   while (elt->parent && elt->parent->right == elt)
6112                     elt = elt->parent;
6113                   elt = elt->parent;
6114                   if (elt
6115                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6116                                            bit_position (elt->purpose))))
6117                     {
6118                       next = elt->purpose;
6119                       break;
6120                     }
6121                 }
6122             }
6123         }
6124     }
6125
6126   /* Ordinarily return, but not if we want to output all
6127      and there are elements left.  */
6128   if (!(all && next != 0))
6129     return;
6130
6131   /* If it's not incremental, just skip over the gap, so that after
6132      jumping to retry we will output the next successive element.  */
6133   if (TREE_CODE (constructor_type) == RECORD_TYPE
6134       || TREE_CODE (constructor_type) == UNION_TYPE)
6135     constructor_unfilled_fields = next;
6136   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6137     constructor_unfilled_index = next;
6138
6139   /* ELT now points to the node in the pending tree with the next
6140      initializer to output.  */
6141   goto retry;
6142 }
6143 \f
6144 /* Add one non-braced element to the current constructor level.
6145    This adjusts the current position within the constructor's type.
6146    This may also start or terminate implicit levels
6147    to handle a partly-braced initializer.
6148
6149    Once this has found the correct level for the new element,
6150    it calls output_init_element.  */
6151
6152 void
6153 process_init_element (struct c_expr value)
6154 {
6155   tree orig_value = value.value;
6156   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6157   bool strict_string = value.original_code == STRING_CST;
6158
6159   designator_depth = 0;
6160   designator_errorneous = 0;
6161
6162   /* Handle superfluous braces around string cst as in
6163      char x[] = {"foo"}; */
6164   if (string_flag
6165       && constructor_type
6166       && TREE_CODE (constructor_type) == ARRAY_TYPE
6167       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6168       && integer_zerop (constructor_unfilled_index))
6169     {
6170       if (constructor_stack->replacement_value.value)
6171         error_init ("excess elements in char array initializer");
6172       constructor_stack->replacement_value = value;
6173       return;
6174     }
6175
6176   if (constructor_stack->replacement_value.value != 0)
6177     {
6178       error_init ("excess elements in struct initializer");
6179       return;
6180     }
6181
6182   /* Ignore elements of a brace group if it is entirely superfluous
6183      and has already been diagnosed.  */
6184   if (constructor_type == 0)
6185     return;
6186
6187   /* If we've exhausted any levels that didn't have braces,
6188      pop them now.  */
6189   while (constructor_stack->implicit)
6190     {
6191       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6192            || TREE_CODE (constructor_type) == UNION_TYPE)
6193           && constructor_fields == 0)
6194         process_init_element (pop_init_level (1));
6195       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6196                && (constructor_max_index == 0
6197                    || tree_int_cst_lt (constructor_max_index,
6198                                        constructor_index)))
6199         process_init_element (pop_init_level (1));
6200       else
6201         break;
6202     }
6203
6204   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6205   if (constructor_range_stack)
6206     {
6207       /* If value is a compound literal and we'll be just using its
6208          content, don't put it into a SAVE_EXPR.  */
6209       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6210           || !require_constant_value
6211           || flag_isoc99)
6212         value.value = save_expr (value.value);
6213     }
6214
6215   while (1)
6216     {
6217       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6218         {
6219           tree fieldtype;
6220           enum tree_code fieldcode;
6221
6222           if (constructor_fields == 0)
6223             {
6224               pedwarn_init ("excess elements in struct initializer");
6225               break;
6226             }
6227
6228           fieldtype = TREE_TYPE (constructor_fields);
6229           if (fieldtype != error_mark_node)
6230             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6231           fieldcode = TREE_CODE (fieldtype);
6232
6233           /* Error for non-static initialization of a flexible array member.  */
6234           if (fieldcode == ARRAY_TYPE
6235               && !require_constant_value
6236               && TYPE_SIZE (fieldtype) == NULL_TREE
6237               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6238             {
6239               error_init ("non-static initialization of a flexible array member");
6240               break;
6241             }
6242
6243           /* Accept a string constant to initialize a subarray.  */
6244           if (value.value != 0
6245               && fieldcode == ARRAY_TYPE
6246               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6247               && string_flag)
6248             value.value = orig_value;
6249           /* Otherwise, if we have come to a subaggregate,
6250              and we don't have an element of its type, push into it.  */
6251           else if (value.value != 0
6252                    && value.value != error_mark_node
6253                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6254                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6255                        || fieldcode == UNION_TYPE))
6256             {
6257               push_init_level (1);
6258               continue;
6259             }
6260
6261           if (value.value)
6262             {
6263               push_member_name (constructor_fields);
6264               output_init_element (value.value, strict_string,
6265                                    fieldtype, constructor_fields, 1);
6266               RESTORE_SPELLING_DEPTH (constructor_depth);
6267             }
6268           else
6269             /* Do the bookkeeping for an element that was
6270                directly output as a constructor.  */
6271             {
6272               /* For a record, keep track of end position of last field.  */
6273               if (DECL_SIZE (constructor_fields))
6274                 constructor_bit_index
6275                   = size_binop (PLUS_EXPR,
6276                                 bit_position (constructor_fields),
6277                                 DECL_SIZE (constructor_fields));
6278
6279               /* If the current field was the first one not yet written out,
6280                  it isn't now, so update.  */
6281               if (constructor_unfilled_fields == constructor_fields)
6282                 {
6283                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6284                   /* Skip any nameless bit fields.  */
6285                   while (constructor_unfilled_fields != 0
6286                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6287                          && DECL_NAME (constructor_unfilled_fields) == 0)
6288                     constructor_unfilled_fields =
6289                       TREE_CHAIN (constructor_unfilled_fields);
6290                 }
6291             }
6292
6293           constructor_fields = TREE_CHAIN (constructor_fields);
6294           /* Skip any nameless bit fields at the beginning.  */
6295           while (constructor_fields != 0
6296                  && DECL_C_BIT_FIELD (constructor_fields)
6297                  && DECL_NAME (constructor_fields) == 0)
6298             constructor_fields = TREE_CHAIN (constructor_fields);
6299         }
6300       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6301         {
6302           tree fieldtype;
6303           enum tree_code fieldcode;
6304
6305           if (constructor_fields == 0)
6306             {
6307               pedwarn_init ("excess elements in union initializer");
6308               break;
6309             }
6310
6311           fieldtype = TREE_TYPE (constructor_fields);
6312           if (fieldtype != error_mark_node)
6313             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6314           fieldcode = TREE_CODE (fieldtype);
6315
6316           /* Warn that traditional C rejects initialization of unions.
6317              We skip the warning if the value is zero.  This is done
6318              under the assumption that the zero initializer in user
6319              code appears conditioned on e.g. __STDC__ to avoid
6320              "missing initializer" warnings and relies on default
6321              initialization to zero in the traditional C case.
6322              We also skip the warning if the initializer is designated,
6323              again on the assumption that this must be conditional on
6324              __STDC__ anyway (and we've already complained about the
6325              member-designator already).  */
6326           if (!in_system_header && !constructor_designated
6327               && !(value.value && (integer_zerop (value.value)
6328                                    || real_zerop (value.value))))
6329             warning (OPT_Wtraditional, "traditional C rejects initialization "
6330                      "of unions");
6331
6332           /* Accept a string constant to initialize a subarray.  */
6333           if (value.value != 0
6334               && fieldcode == ARRAY_TYPE
6335               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6336               && string_flag)
6337             value.value = orig_value;
6338           /* Otherwise, if we have come to a subaggregate,
6339              and we don't have an element of its type, push into it.  */
6340           else if (value.value != 0
6341                    && value.value != error_mark_node
6342                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6343                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6344                        || fieldcode == UNION_TYPE))
6345             {
6346               push_init_level (1);
6347               continue;
6348             }
6349
6350           if (value.value)
6351             {
6352               push_member_name (constructor_fields);
6353               output_init_element (value.value, strict_string,
6354                                    fieldtype, constructor_fields, 1);
6355               RESTORE_SPELLING_DEPTH (constructor_depth);
6356             }
6357           else
6358             /* Do the bookkeeping for an element that was
6359                directly output as a constructor.  */
6360             {
6361               constructor_bit_index = DECL_SIZE (constructor_fields);
6362               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6363             }
6364
6365           constructor_fields = 0;
6366         }
6367       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6368         {
6369           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6370           enum tree_code eltcode = TREE_CODE (elttype);
6371
6372           /* Accept a string constant to initialize a subarray.  */
6373           if (value.value != 0
6374               && eltcode == ARRAY_TYPE
6375               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6376               && string_flag)
6377             value.value = orig_value;
6378           /* Otherwise, if we have come to a subaggregate,
6379              and we don't have an element of its type, push into it.  */
6380           else if (value.value != 0
6381                    && value.value != error_mark_node
6382                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6383                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6384                        || eltcode == UNION_TYPE))
6385             {
6386               push_init_level (1);
6387               continue;
6388             }
6389
6390           if (constructor_max_index != 0
6391               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6392                   || integer_all_onesp (constructor_max_index)))
6393             {
6394               pedwarn_init ("excess elements in array initializer");
6395               break;
6396             }
6397
6398           /* Now output the actual element.  */
6399           if (value.value)
6400             {
6401               push_array_bounds (tree_low_cst (constructor_index, 0));
6402               output_init_element (value.value, strict_string,
6403                                    elttype, constructor_index, 1);
6404               RESTORE_SPELLING_DEPTH (constructor_depth);
6405             }
6406
6407           constructor_index
6408             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6409
6410           if (!value.value)
6411             /* If we are doing the bookkeeping for an element that was
6412                directly output as a constructor, we must update
6413                constructor_unfilled_index.  */
6414             constructor_unfilled_index = constructor_index;
6415         }
6416       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6417         {
6418           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6419
6420          /* Do a basic check of initializer size.  Note that vectors
6421             always have a fixed size derived from their type.  */
6422           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6423             {
6424               pedwarn_init ("excess elements in vector initializer");
6425               break;
6426             }
6427
6428           /* Now output the actual element.  */
6429           if (value.value)
6430             output_init_element (value.value, strict_string,
6431                                  elttype, constructor_index, 1);
6432
6433           constructor_index
6434             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6435
6436           if (!value.value)
6437             /* If we are doing the bookkeeping for an element that was
6438                directly output as a constructor, we must update
6439                constructor_unfilled_index.  */
6440             constructor_unfilled_index = constructor_index;
6441         }
6442
6443       /* Handle the sole element allowed in a braced initializer
6444          for a scalar variable.  */
6445       else if (constructor_type != error_mark_node
6446                && constructor_fields == 0)
6447         {
6448           pedwarn_init ("excess elements in scalar initializer");
6449           break;
6450         }
6451       else
6452         {
6453           if (value.value)
6454             output_init_element (value.value, strict_string,
6455                                  constructor_type, NULL_TREE, 1);
6456           constructor_fields = 0;
6457         }
6458
6459       /* Handle range initializers either at this level or anywhere higher
6460          in the designator stack.  */
6461       if (constructor_range_stack)
6462         {
6463           struct constructor_range_stack *p, *range_stack;
6464           int finish = 0;
6465
6466           range_stack = constructor_range_stack;
6467           constructor_range_stack = 0;
6468           while (constructor_stack != range_stack->stack)
6469             {
6470               gcc_assert (constructor_stack->implicit);
6471               process_init_element (pop_init_level (1));
6472             }
6473           for (p = range_stack;
6474                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6475                p = p->prev)
6476             {
6477               gcc_assert (constructor_stack->implicit);
6478               process_init_element (pop_init_level (1));
6479             }
6480
6481           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6482           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6483             finish = 1;
6484
6485           while (1)
6486             {
6487               constructor_index = p->index;
6488               constructor_fields = p->fields;
6489               if (finish && p->range_end && p->index == p->range_start)
6490                 {
6491                   finish = 0;
6492                   p->prev = 0;
6493                 }
6494               p = p->next;
6495               if (!p)
6496                 break;
6497               push_init_level (2);
6498               p->stack = constructor_stack;
6499               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6500                 p->index = p->range_start;
6501             }
6502
6503           if (!finish)
6504             constructor_range_stack = range_stack;
6505           continue;
6506         }
6507
6508       break;
6509     }
6510
6511   constructor_range_stack = 0;
6512 }
6513 \f
6514 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6515    (guaranteed to be 'volatile' or null) and ARGS (represented using
6516    an ASM_EXPR node).  */
6517 tree
6518 build_asm_stmt (tree cv_qualifier, tree args)
6519 {
6520   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6521     ASM_VOLATILE_P (args) = 1;
6522   return add_stmt (args);
6523 }
6524
6525 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6526    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6527    SIMPLE indicates whether there was anything at all after the
6528    string in the asm expression -- asm("blah") and asm("blah" : )
6529    are subtly different.  We use a ASM_EXPR node to represent this.  */
6530 tree
6531 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6532                 bool simple)
6533 {
6534   tree tail;
6535   tree args;
6536   int i;
6537   const char *constraint;
6538   const char **oconstraints;
6539   bool allows_mem, allows_reg, is_inout;
6540   int ninputs, noutputs;
6541
6542   ninputs = list_length (inputs);
6543   noutputs = list_length (outputs);
6544   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6545
6546   string = resolve_asm_operand_names (string, outputs, inputs);
6547
6548   /* Remove output conversions that change the type but not the mode.  */
6549   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6550     {
6551       tree output = TREE_VALUE (tail);
6552
6553       /* ??? Really, this should not be here.  Users should be using a
6554          proper lvalue, dammit.  But there's a long history of using casts
6555          in the output operands.  In cases like longlong.h, this becomes a
6556          primitive form of typechecking -- if the cast can be removed, then
6557          the output operand had a type of the proper width; otherwise we'll
6558          get an error.  Gross, but ...  */
6559       STRIP_NOPS (output);
6560
6561       if (!lvalue_or_else (output, lv_asm))
6562         output = error_mark_node;
6563
6564       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6565       oconstraints[i] = constraint;
6566
6567       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6568                                    &allows_mem, &allows_reg, &is_inout))
6569         {
6570           /* If the operand is going to end up in memory,
6571              mark it addressable.  */
6572           if (!allows_reg && !c_mark_addressable (output))
6573             output = error_mark_node;
6574         }
6575       else
6576         output = error_mark_node;
6577
6578       TREE_VALUE (tail) = output;
6579     }
6580
6581   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6582     {
6583       tree input;
6584
6585       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6586       input = TREE_VALUE (tail);
6587
6588       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6589                                   oconstraints, &allows_mem, &allows_reg))
6590         {
6591           /* If the operand is going to end up in memory,
6592              mark it addressable.  */
6593           if (!allows_reg && allows_mem)
6594             {
6595               /* Strip the nops as we allow this case.  FIXME, this really
6596                  should be rejected or made deprecated.  */
6597               STRIP_NOPS (input);
6598               if (!c_mark_addressable (input))
6599                 input = error_mark_node;
6600           }
6601         }
6602       else
6603         input = error_mark_node;
6604
6605       TREE_VALUE (tail) = input;
6606     }
6607
6608   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6609
6610   /* Simple asm statements are treated as volatile.  */
6611   if (simple)
6612     {
6613       ASM_VOLATILE_P (args) = 1;
6614       ASM_INPUT_P (args) = 1;
6615     }
6616
6617   return args;
6618 }
6619 \f
6620 /* Generate a goto statement to LABEL.  */
6621
6622 tree
6623 c_finish_goto_label (tree label)
6624 {
6625   tree decl = lookup_label (label);
6626   if (!decl)
6627     return NULL_TREE;
6628
6629   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6630     {
6631       error ("jump into statement expression");
6632       return NULL_TREE;
6633     }
6634
6635   if (C_DECL_UNJUMPABLE_VM (decl))
6636     {
6637       error ("jump into scope of identifier with variably modified type");
6638       return NULL_TREE;
6639     }
6640
6641   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6642     {
6643       /* No jump from outside this statement expression context, so
6644          record that there is a jump from within this context.  */
6645       struct c_label_list *nlist;
6646       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6647       nlist->next = label_context_stack_se->labels_used;
6648       nlist->label = decl;
6649       label_context_stack_se->labels_used = nlist;
6650     }
6651
6652   if (!C_DECL_UNDEFINABLE_VM (decl))
6653     {
6654       /* No jump from outside this context context of identifiers with
6655          variably modified type, so record that there is a jump from
6656          within this context.  */
6657       struct c_label_list *nlist;
6658       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6659       nlist->next = label_context_stack_vm->labels_used;
6660       nlist->label = decl;
6661       label_context_stack_vm->labels_used = nlist;
6662     }
6663
6664   TREE_USED (decl) = 1;
6665   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6666 }
6667
6668 /* Generate a computed goto statement to EXPR.  */
6669
6670 tree
6671 c_finish_goto_ptr (tree expr)
6672 {
6673   if (pedantic)
6674     pedwarn ("ISO C forbids %<goto *expr;%>");
6675   expr = convert (ptr_type_node, expr);
6676   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6677 }
6678
6679 /* Generate a C `return' statement.  RETVAL is the expression for what
6680    to return, or a null pointer for `return;' with no value.  */
6681
6682 tree
6683 c_finish_return (tree retval)
6684 {
6685   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6686
6687   if (TREE_THIS_VOLATILE (current_function_decl))
6688     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6689
6690   if (!retval)
6691     {
6692       current_function_returns_null = 1;
6693       if ((warn_return_type || flag_isoc99)
6694           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6695         pedwarn_c99 ("%<return%> with no value, in "
6696                      "function returning non-void");
6697     }
6698   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6699     {
6700       current_function_returns_null = 1;
6701       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6702         pedwarn ("%<return%> with a value, in function returning void");
6703     }
6704   else
6705     {
6706       tree t = convert_for_assignment (valtype, retval, ic_return,
6707                                        NULL_TREE, NULL_TREE, 0);
6708       tree res = DECL_RESULT (current_function_decl);
6709       tree inner;
6710
6711       current_function_returns_value = 1;
6712       if (t == error_mark_node)
6713         return NULL_TREE;
6714
6715       inner = t = convert (TREE_TYPE (res), t);
6716
6717       /* Strip any conversions, additions, and subtractions, and see if
6718          we are returning the address of a local variable.  Warn if so.  */
6719       while (1)
6720         {
6721           switch (TREE_CODE (inner))
6722             {
6723             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6724             case PLUS_EXPR:
6725               inner = TREE_OPERAND (inner, 0);
6726               continue;
6727
6728             case MINUS_EXPR:
6729               /* If the second operand of the MINUS_EXPR has a pointer
6730                  type (or is converted from it), this may be valid, so
6731                  don't give a warning.  */
6732               {
6733                 tree op1 = TREE_OPERAND (inner, 1);
6734
6735                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6736                        && (TREE_CODE (op1) == NOP_EXPR
6737                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6738                            || TREE_CODE (op1) == CONVERT_EXPR))
6739                   op1 = TREE_OPERAND (op1, 0);
6740
6741                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6742                   break;
6743
6744                 inner = TREE_OPERAND (inner, 0);
6745                 continue;
6746               }
6747
6748             case ADDR_EXPR:
6749               inner = TREE_OPERAND (inner, 0);
6750
6751               while (REFERENCE_CLASS_P (inner)
6752                      && TREE_CODE (inner) != INDIRECT_REF)
6753                 inner = TREE_OPERAND (inner, 0);
6754
6755               if (DECL_P (inner)
6756                   && !DECL_EXTERNAL (inner)
6757                   && !TREE_STATIC (inner)
6758                   && DECL_CONTEXT (inner) == current_function_decl)
6759                 warning (0, "function returns address of local variable");
6760               break;
6761
6762             default:
6763               break;
6764             }
6765
6766           break;
6767         }
6768
6769       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6770     }
6771
6772   return add_stmt (build_stmt (RETURN_EXPR, retval));
6773 }
6774 \f
6775 struct c_switch {
6776   /* The SWITCH_EXPR being built.  */
6777   tree switch_expr;
6778
6779   /* The original type of the testing expression, i.e. before the
6780      default conversion is applied.  */
6781   tree orig_type;
6782
6783   /* A splay-tree mapping the low element of a case range to the high
6784      element, or NULL_TREE if there is no high element.  Used to
6785      determine whether or not a new case label duplicates an old case
6786      label.  We need a tree, rather than simply a hash table, because
6787      of the GNU case range extension.  */
6788   splay_tree cases;
6789
6790   /* Number of nested statement expressions within this switch
6791      statement; if nonzero, case and default labels may not
6792      appear.  */
6793   unsigned int blocked_stmt_expr;
6794
6795   /* Scope of outermost declarations of identifiers with variably
6796      modified type within this switch statement; if nonzero, case and
6797      default labels may not appear.  */
6798   unsigned int blocked_vm;
6799
6800   /* The next node on the stack.  */
6801   struct c_switch *next;
6802 };
6803
6804 /* A stack of the currently active switch statements.  The innermost
6805    switch statement is on the top of the stack.  There is no need to
6806    mark the stack for garbage collection because it is only active
6807    during the processing of the body of a function, and we never
6808    collect at that point.  */
6809
6810 struct c_switch *c_switch_stack;
6811
6812 /* Start a C switch statement, testing expression EXP.  Return the new
6813    SWITCH_EXPR.  */
6814
6815 tree
6816 c_start_case (tree exp)
6817 {
6818   enum tree_code code;
6819   tree type, orig_type = error_mark_node;
6820   struct c_switch *cs;
6821
6822   if (exp != error_mark_node)
6823     {
6824       code = TREE_CODE (TREE_TYPE (exp));
6825       orig_type = TREE_TYPE (exp);
6826
6827       if (!INTEGRAL_TYPE_P (orig_type)
6828           && code != ERROR_MARK)
6829         {
6830           error ("switch quantity not an integer");
6831           exp = integer_zero_node;
6832           orig_type = error_mark_node;
6833         }
6834       else
6835         {
6836           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6837
6838           if (!in_system_header
6839               && (type == long_integer_type_node
6840                   || type == long_unsigned_type_node))
6841             warning (OPT_Wtraditional, "%<long%> switch expression not "
6842                      "converted to %<int%> in ISO C");
6843
6844           exp = default_conversion (exp);
6845           type = TREE_TYPE (exp);
6846         }
6847     }
6848
6849   /* Add this new SWITCH_EXPR to the stack.  */
6850   cs = XNEW (struct c_switch);
6851   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6852   cs->orig_type = orig_type;
6853   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6854   cs->blocked_stmt_expr = 0;
6855   cs->blocked_vm = 0;
6856   cs->next = c_switch_stack;
6857   c_switch_stack = cs;
6858
6859   return add_stmt (cs->switch_expr);
6860 }
6861
6862 /* Process a case label.  */
6863
6864 tree
6865 do_case (tree low_value, tree high_value)
6866 {
6867   tree label = NULL_TREE;
6868
6869   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
6870       && !c_switch_stack->blocked_vm)
6871     {
6872       label = c_add_case_label (c_switch_stack->cases,
6873                                 SWITCH_COND (c_switch_stack->switch_expr),
6874                                 c_switch_stack->orig_type,
6875                                 low_value, high_value);
6876       if (label == error_mark_node)
6877         label = NULL_TREE;
6878     }
6879   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
6880     {
6881       if (low_value)
6882         error ("case label in statement expression not containing "
6883                "enclosing switch statement");
6884       else
6885         error ("%<default%> label in statement expression not containing "
6886                "enclosing switch statement");
6887     }
6888   else if (c_switch_stack && c_switch_stack->blocked_vm)
6889     {
6890       if (low_value)
6891         error ("case label in scope of identifier with variably modified "
6892                "type not containing enclosing switch statement");
6893       else
6894         error ("%<default%> label in scope of identifier with variably "
6895                "modified type not containing enclosing switch statement");
6896     }
6897   else if (low_value)
6898     error ("case label not within a switch statement");
6899   else
6900     error ("%<default%> label not within a switch statement");
6901
6902   return label;
6903 }
6904
6905 /* Finish the switch statement.  */
6906
6907 void
6908 c_finish_case (tree body)
6909 {
6910   struct c_switch *cs = c_switch_stack;
6911   location_t switch_location;
6912
6913   SWITCH_BODY (cs->switch_expr) = body;
6914
6915   /* We must not be within a statement expression nested in the switch
6916      at this point; we might, however, be within the scope of an
6917      identifier with variably modified type nested in the switch.  */
6918   gcc_assert (!cs->blocked_stmt_expr);
6919
6920   /* Emit warnings as needed.  */
6921   if (EXPR_HAS_LOCATION (cs->switch_expr))
6922     switch_location = EXPR_LOCATION (cs->switch_expr);
6923   else
6924     switch_location = input_location;
6925   c_do_switch_warnings (cs->cases, switch_location,
6926                         TREE_TYPE (cs->switch_expr),
6927                         SWITCH_COND (cs->switch_expr));
6928
6929   /* Pop the stack.  */
6930   c_switch_stack = cs->next;
6931   splay_tree_delete (cs->cases);
6932   XDELETE (cs);
6933 }
6934 \f
6935 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6936    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6937    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6938    statement, and was not surrounded with parenthesis.  */
6939
6940 void
6941 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6942                   tree else_block, bool nested_if)
6943 {
6944   tree stmt;
6945
6946   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6947   if (warn_parentheses && nested_if && else_block == NULL)
6948     {
6949       tree inner_if = then_block;
6950
6951       /* We know from the grammar productions that there is an IF nested
6952          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6953          it might not be exactly THEN_BLOCK, but should be the last
6954          non-container statement within.  */
6955       while (1)
6956         switch (TREE_CODE (inner_if))
6957           {
6958           case COND_EXPR:
6959             goto found;
6960           case BIND_EXPR:
6961             inner_if = BIND_EXPR_BODY (inner_if);
6962             break;
6963           case STATEMENT_LIST:
6964             inner_if = expr_last (then_block);
6965             break;
6966           case TRY_FINALLY_EXPR:
6967           case TRY_CATCH_EXPR:
6968             inner_if = TREE_OPERAND (inner_if, 0);
6969             break;
6970           default:
6971             gcc_unreachable ();
6972           }
6973     found:
6974
6975       if (COND_EXPR_ELSE (inner_if))
6976          warning (OPT_Wparentheses,
6977                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
6978                   &if_locus);
6979     }
6980
6981   /* Diagnose ";" via the special empty statement node that we create.  */
6982   if (extra_warnings)
6983     {
6984       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
6985         {
6986           if (!else_block)
6987             warning (0, "%Hempty body in an if-statement",
6988                      EXPR_LOCUS (then_block));
6989           then_block = alloc_stmt_list ();
6990         }
6991       if (else_block
6992           && TREE_CODE (else_block) == NOP_EXPR
6993           && !TREE_TYPE (else_block))
6994         {
6995           warning (0, "%Hempty body in an else-statement",
6996                    EXPR_LOCUS (else_block));
6997           else_block = alloc_stmt_list ();
6998         }
6999     }
7000
7001   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7002   SET_EXPR_LOCATION (stmt, if_locus);
7003   add_stmt (stmt);
7004 }
7005
7006 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7007    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7008    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7009    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7010    the continue label.  Everything is allowed to be NULL.  */
7011
7012 void
7013 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7014                tree blab, tree clab, bool cond_is_first)
7015 {
7016   tree entry = NULL, exit = NULL, t;
7017
7018   /* If the condition is zero don't generate a loop construct.  */
7019   if (cond && integer_zerop (cond))
7020     {
7021       if (cond_is_first)
7022         {
7023           t = build_and_jump (&blab);
7024           SET_EXPR_LOCATION (t, start_locus);
7025           add_stmt (t);
7026         }
7027     }
7028   else
7029     {
7030       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7031
7032       /* If we have an exit condition, then we build an IF with gotos either
7033          out of the loop, or to the top of it.  If there's no exit condition,
7034          then we just build a jump back to the top.  */
7035       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7036
7037       if (cond && !integer_nonzerop (cond))
7038         {
7039           /* Canonicalize the loop condition to the end.  This means
7040              generating a branch to the loop condition.  Reuse the
7041              continue label, if possible.  */
7042           if (cond_is_first)
7043             {
7044               if (incr || !clab)
7045                 {
7046                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7047                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7048                 }
7049               else
7050                 t = build1 (GOTO_EXPR, void_type_node, clab);
7051               SET_EXPR_LOCATION (t, start_locus);
7052               add_stmt (t);
7053             }
7054
7055           t = build_and_jump (&blab);
7056           exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
7057           exit = fold (exit);
7058           if (cond_is_first)
7059             SET_EXPR_LOCATION (exit, start_locus);
7060           else
7061             SET_EXPR_LOCATION (exit, input_location);
7062         }
7063
7064       add_stmt (top);
7065     }
7066
7067   if (body)
7068     add_stmt (body);
7069   if (clab)
7070     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7071   if (incr)
7072     add_stmt (incr);
7073   if (entry)
7074     add_stmt (entry);
7075   if (exit)
7076     add_stmt (exit);
7077   if (blab)
7078     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7079 }
7080
7081 tree
7082 c_finish_bc_stmt (tree *label_p, bool is_break)
7083 {
7084   bool skip;
7085   tree label = *label_p;
7086
7087   /* In switch statements break is sometimes stylistically used after
7088      a return statement.  This can lead to spurious warnings about
7089      control reaching the end of a non-void function when it is
7090      inlined.  Note that we are calling block_may_fallthru with
7091      language specific tree nodes; this works because
7092      block_may_fallthru returns true when given something it does not
7093      understand.  */
7094   skip = !block_may_fallthru (cur_stmt_list);
7095
7096   if (!label)
7097     {
7098       if (!skip)
7099         *label_p = label = create_artificial_label ();
7100     }
7101   else if (TREE_CODE (label) != LABEL_DECL)
7102     {
7103       if (is_break)
7104         error ("break statement not within loop or switch");
7105       else
7106         error ("continue statement not within a loop");
7107       return NULL_TREE;
7108     }
7109
7110   if (skip)
7111     return NULL_TREE;
7112
7113   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7114 }
7115
7116 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7117
7118 static void
7119 emit_side_effect_warnings (tree expr)
7120 {
7121   if (expr == error_mark_node)
7122     ;
7123   else if (!TREE_SIDE_EFFECTS (expr))
7124     {
7125       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7126         warning (0, "%Hstatement with no effect",
7127                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7128     }
7129   else if (warn_unused_value)
7130     warn_if_unused_value (expr, input_location);
7131 }
7132
7133 /* Process an expression as if it were a complete statement.  Emit
7134    diagnostics, but do not call ADD_STMT.  */
7135
7136 tree
7137 c_process_expr_stmt (tree expr)
7138 {
7139   if (!expr)
7140     return NULL_TREE;
7141
7142   if (warn_sequence_point)
7143     verify_sequence_points (expr);
7144
7145   if (TREE_TYPE (expr) != error_mark_node
7146       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7147       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7148     error ("expression statement has incomplete type");
7149
7150   /* If we're not processing a statement expression, warn about unused values.
7151      Warnings for statement expressions will be emitted later, once we figure
7152      out which is the result.  */
7153   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7154       && (extra_warnings || warn_unused_value))
7155     emit_side_effect_warnings (expr);
7156
7157   /* If the expression is not of a type to which we cannot assign a line
7158      number, wrap the thing in a no-op NOP_EXPR.  */
7159   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7160     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7161
7162   if (EXPR_P (expr))
7163     SET_EXPR_LOCATION (expr, input_location);
7164
7165   return expr;
7166 }
7167
7168 /* Emit an expression as a statement.  */
7169
7170 tree
7171 c_finish_expr_stmt (tree expr)
7172 {
7173   if (expr)
7174     return add_stmt (c_process_expr_stmt (expr));
7175   else
7176     return NULL;
7177 }
7178
7179 /* Do the opposite and emit a statement as an expression.  To begin,
7180    create a new binding level and return it.  */
7181
7182 tree
7183 c_begin_stmt_expr (void)
7184 {
7185   tree ret;
7186   struct c_label_context_se *nstack;
7187   struct c_label_list *glist;
7188
7189   /* We must force a BLOCK for this level so that, if it is not expanded
7190      later, there is a way to turn off the entire subtree of blocks that
7191      are contained in it.  */
7192   keep_next_level ();
7193   ret = c_begin_compound_stmt (true);
7194   if (c_switch_stack)
7195     {
7196       c_switch_stack->blocked_stmt_expr++;
7197       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7198     }
7199   for (glist = label_context_stack_se->labels_used;
7200        glist != NULL;
7201        glist = glist->next)
7202     {
7203       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7204     }
7205   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7206   nstack->labels_def = NULL;
7207   nstack->labels_used = NULL;
7208   nstack->next = label_context_stack_se;
7209   label_context_stack_se = nstack;
7210
7211   /* Mark the current statement list as belonging to a statement list.  */
7212   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7213
7214   return ret;
7215 }
7216
7217 tree
7218 c_finish_stmt_expr (tree body)
7219 {
7220   tree last, type, tmp, val;
7221   tree *last_p;
7222   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7223
7224   body = c_end_compound_stmt (body, true);
7225   if (c_switch_stack)
7226     {
7227       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7228       c_switch_stack->blocked_stmt_expr--;
7229     }
7230   /* It is no longer possible to jump to labels defined within this
7231      statement expression.  */
7232   for (dlist = label_context_stack_se->labels_def;
7233        dlist != NULL;
7234        dlist = dlist->next)
7235     {
7236       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7237     }
7238   /* It is again possible to define labels with a goto just outside
7239      this statement expression.  */
7240   for (glist = label_context_stack_se->next->labels_used;
7241        glist != NULL;
7242        glist = glist->next)
7243     {
7244       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7245       glist_prev = glist;
7246     }
7247   if (glist_prev != NULL)
7248     glist_prev->next = label_context_stack_se->labels_used;
7249   else
7250     label_context_stack_se->next->labels_used
7251       = label_context_stack_se->labels_used;
7252   label_context_stack_se = label_context_stack_se->next;
7253
7254   /* Locate the last statement in BODY.  See c_end_compound_stmt
7255      about always returning a BIND_EXPR.  */
7256   last_p = &BIND_EXPR_BODY (body);
7257   last = BIND_EXPR_BODY (body);
7258
7259  continue_searching:
7260   if (TREE_CODE (last) == STATEMENT_LIST)
7261     {
7262       tree_stmt_iterator i;
7263
7264       /* This can happen with degenerate cases like ({ }).  No value.  */
7265       if (!TREE_SIDE_EFFECTS (last))
7266         return body;
7267
7268       /* If we're supposed to generate side effects warnings, process
7269          all of the statements except the last.  */
7270       if (extra_warnings || warn_unused_value)
7271         {
7272           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7273             emit_side_effect_warnings (tsi_stmt (i));
7274         }
7275       else
7276         i = tsi_last (last);
7277       last_p = tsi_stmt_ptr (i);
7278       last = *last_p;
7279     }
7280
7281   /* If the end of the list is exception related, then the list was split
7282      by a call to push_cleanup.  Continue searching.  */
7283   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7284       || TREE_CODE (last) == TRY_CATCH_EXPR)
7285     {
7286       last_p = &TREE_OPERAND (last, 0);
7287       last = *last_p;
7288       goto continue_searching;
7289     }
7290
7291   /* In the case that the BIND_EXPR is not necessary, return the
7292      expression out from inside it.  */
7293   if (last == error_mark_node
7294       || (last == BIND_EXPR_BODY (body)
7295           && BIND_EXPR_VARS (body) == NULL))
7296     return last;
7297
7298   /* Extract the type of said expression.  */
7299   type = TREE_TYPE (last);
7300
7301   /* If we're not returning a value at all, then the BIND_EXPR that
7302      we already have is a fine expression to return.  */
7303   if (!type || VOID_TYPE_P (type))
7304     return body;
7305
7306   /* Now that we've located the expression containing the value, it seems
7307      silly to make voidify_wrapper_expr repeat the process.  Create a
7308      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7309   tmp = create_tmp_var_raw (type, NULL);
7310
7311   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7312      tree_expr_nonnegative_p giving up immediately.  */
7313   val = last;
7314   if (TREE_CODE (val) == NOP_EXPR
7315       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7316     val = TREE_OPERAND (val, 0);
7317
7318   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7319   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7320
7321   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7322 }
7323
7324 /* Begin the scope of an identifier of variably modified type, scope
7325    number SCOPE.  Jumping from outside this scope to inside it is not
7326    permitted.  */
7327
7328 void
7329 c_begin_vm_scope (unsigned int scope)
7330 {
7331   struct c_label_context_vm *nstack;
7332   struct c_label_list *glist;
7333
7334   gcc_assert (scope > 0);
7335   if (c_switch_stack && !c_switch_stack->blocked_vm)
7336     c_switch_stack->blocked_vm = scope;
7337   for (glist = label_context_stack_vm->labels_used;
7338        glist != NULL;
7339        glist = glist->next)
7340     {
7341       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7342     }
7343   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7344   nstack->labels_def = NULL;
7345   nstack->labels_used = NULL;
7346   nstack->scope = scope;
7347   nstack->next = label_context_stack_vm;
7348   label_context_stack_vm = nstack;
7349 }
7350
7351 /* End a scope which may contain identifiers of variably modified
7352    type, scope number SCOPE.  */
7353
7354 void
7355 c_end_vm_scope (unsigned int scope)
7356 {
7357   if (label_context_stack_vm == NULL)
7358     return;
7359   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7360     c_switch_stack->blocked_vm = 0;
7361   /* We may have a number of nested scopes of identifiers with
7362      variably modified type, all at this depth.  Pop each in turn.  */
7363   while (label_context_stack_vm->scope == scope)
7364     {
7365       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7366
7367       /* It is no longer possible to jump to labels defined within this
7368          scope.  */
7369       for (dlist = label_context_stack_vm->labels_def;
7370            dlist != NULL;
7371            dlist = dlist->next)
7372         {
7373           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7374         }
7375       /* It is again possible to define labels with a goto just outside
7376          this scope.  */
7377       for (glist = label_context_stack_vm->next->labels_used;
7378            glist != NULL;
7379            glist = glist->next)
7380         {
7381           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7382           glist_prev = glist;
7383         }
7384       if (glist_prev != NULL)
7385         glist_prev->next = label_context_stack_vm->labels_used;
7386       else
7387         label_context_stack_vm->next->labels_used
7388           = label_context_stack_vm->labels_used;
7389       label_context_stack_vm = label_context_stack_vm->next;
7390     }
7391 }
7392 \f
7393 /* Begin and end compound statements.  This is as simple as pushing
7394    and popping new statement lists from the tree.  */
7395
7396 tree
7397 c_begin_compound_stmt (bool do_scope)
7398 {
7399   tree stmt = push_stmt_list ();
7400   if (do_scope)
7401     push_scope ();
7402   return stmt;
7403 }
7404
7405 tree
7406 c_end_compound_stmt (tree stmt, bool do_scope)
7407 {
7408   tree block = NULL;
7409
7410   if (do_scope)
7411     {
7412       if (c_dialect_objc ())
7413         objc_clear_super_receiver ();
7414       block = pop_scope ();
7415     }
7416
7417   stmt = pop_stmt_list (stmt);
7418   stmt = c_build_bind_expr (block, stmt);
7419
7420   /* If this compound statement is nested immediately inside a statement
7421      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7422      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7423      STATEMENT_LISTs merge, and thus we can lose track of what statement
7424      was really last.  */
7425   if (cur_stmt_list
7426       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7427       && TREE_CODE (stmt) != BIND_EXPR)
7428     {
7429       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7430       TREE_SIDE_EFFECTS (stmt) = 1;
7431     }
7432
7433   return stmt;
7434 }
7435
7436 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7437    when the current scope is exited.  EH_ONLY is true when this is not
7438    meant to apply to normal control flow transfer.  */
7439
7440 void
7441 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7442 {
7443   enum tree_code code;
7444   tree stmt, list;
7445   bool stmt_expr;
7446
7447   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7448   stmt = build_stmt (code, NULL, cleanup);
7449   add_stmt (stmt);
7450   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7451   list = push_stmt_list ();
7452   TREE_OPERAND (stmt, 0) = list;
7453   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7454 }
7455 \f
7456 /* Build a binary-operation expression without default conversions.
7457    CODE is the kind of expression to build.
7458    This function differs from `build' in several ways:
7459    the data type of the result is computed and recorded in it,
7460    warnings are generated if arg data types are invalid,
7461    special handling for addition and subtraction of pointers is known,
7462    and some optimization is done (operations on narrow ints
7463    are done in the narrower type when that gives the same result).
7464    Constant folding is also done before the result is returned.
7465
7466    Note that the operands will never have enumeral types, or function
7467    or array types, because either they will have the default conversions
7468    performed or they have both just been converted to some other type in which
7469    the arithmetic is to be done.  */
7470
7471 tree
7472 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7473                  int convert_p)
7474 {
7475   tree type0, type1;
7476   enum tree_code code0, code1;
7477   tree op0, op1;
7478   const char *invalid_op_diag;
7479
7480   /* Expression code to give to the expression when it is built.
7481      Normally this is CODE, which is what the caller asked for,
7482      but in some special cases we change it.  */
7483   enum tree_code resultcode = code;
7484
7485   /* Data type in which the computation is to be performed.
7486      In the simplest cases this is the common type of the arguments.  */
7487   tree result_type = NULL;
7488
7489   /* Nonzero means operands have already been type-converted
7490      in whatever way is necessary.
7491      Zero means they need to be converted to RESULT_TYPE.  */
7492   int converted = 0;
7493
7494   /* Nonzero means create the expression with this type, rather than
7495      RESULT_TYPE.  */
7496   tree build_type = 0;
7497
7498   /* Nonzero means after finally constructing the expression
7499      convert it to this type.  */
7500   tree final_type = 0;
7501
7502   /* Nonzero if this is an operation like MIN or MAX which can
7503      safely be computed in short if both args are promoted shorts.
7504      Also implies COMMON.
7505      -1 indicates a bitwise operation; this makes a difference
7506      in the exact conditions for when it is safe to do the operation
7507      in a narrower mode.  */
7508   int shorten = 0;
7509
7510   /* Nonzero if this is a comparison operation;
7511      if both args are promoted shorts, compare the original shorts.
7512      Also implies COMMON.  */
7513   int short_compare = 0;
7514
7515   /* Nonzero if this is a right-shift operation, which can be computed on the
7516      original short and then promoted if the operand is a promoted short.  */
7517   int short_shift = 0;
7518
7519   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7520   int common = 0;
7521
7522   /* True means types are compatible as far as ObjC is concerned.  */
7523   bool objc_ok;
7524
7525   if (convert_p)
7526     {
7527       op0 = default_conversion (orig_op0);
7528       op1 = default_conversion (orig_op1);
7529     }
7530   else
7531     {
7532       op0 = orig_op0;
7533       op1 = orig_op1;
7534     }
7535
7536   type0 = TREE_TYPE (op0);
7537   type1 = TREE_TYPE (op1);
7538
7539   /* The expression codes of the data types of the arguments tell us
7540      whether the arguments are integers, floating, pointers, etc.  */
7541   code0 = TREE_CODE (type0);
7542   code1 = TREE_CODE (type1);
7543
7544   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7545   STRIP_TYPE_NOPS (op0);
7546   STRIP_TYPE_NOPS (op1);
7547
7548   /* If an error was already reported for one of the arguments,
7549      avoid reporting another error.  */
7550
7551   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7552     return error_mark_node;
7553
7554   if ((invalid_op_diag
7555        = targetm.invalid_binary_op (code, type0, type1)))
7556     {
7557       error (invalid_op_diag);
7558       return error_mark_node;
7559     }
7560
7561   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7562
7563   switch (code)
7564     {
7565     case PLUS_EXPR:
7566       /* Handle the pointer + int case.  */
7567       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7568         return pointer_int_sum (PLUS_EXPR, op0, op1);
7569       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7570         return pointer_int_sum (PLUS_EXPR, op1, op0);
7571       else
7572         common = 1;
7573       break;
7574
7575     case MINUS_EXPR:
7576       /* Subtraction of two similar pointers.
7577          We must subtract them as integers, then divide by object size.  */
7578       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7579           && comp_target_types (type0, type1))
7580         return pointer_diff (op0, op1);
7581       /* Handle pointer minus int.  Just like pointer plus int.  */
7582       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7583         return pointer_int_sum (MINUS_EXPR, op0, op1);
7584       else
7585         common = 1;
7586       break;
7587
7588     case MULT_EXPR:
7589       common = 1;
7590       break;
7591
7592     case TRUNC_DIV_EXPR:
7593     case CEIL_DIV_EXPR:
7594     case FLOOR_DIV_EXPR:
7595     case ROUND_DIV_EXPR:
7596     case EXACT_DIV_EXPR:
7597       /* Floating point division by zero is a legitimate way to obtain
7598          infinities and NaNs.  */
7599       if (skip_evaluation == 0 && integer_zerop (op1))
7600         warning (OPT_Wdiv_by_zero, "division by zero");
7601
7602       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7603            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7604           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7605               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7606         {
7607           enum tree_code tcode0 = code0, tcode1 = code1;
7608
7609           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7610             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7611           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7612             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7613
7614           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7615             resultcode = RDIV_EXPR;
7616           else
7617             /* Although it would be tempting to shorten always here, that
7618                loses on some targets, since the modulo instruction is
7619                undefined if the quotient can't be represented in the
7620                computation mode.  We shorten only if unsigned or if
7621                dividing by something we know != -1.  */
7622             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7623                        || (TREE_CODE (op1) == INTEGER_CST
7624                            && !integer_all_onesp (op1)));
7625           common = 1;
7626         }
7627       break;
7628
7629     case BIT_AND_EXPR:
7630     case BIT_IOR_EXPR:
7631     case BIT_XOR_EXPR:
7632       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7633         shorten = -1;
7634       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7635         common = 1;
7636       break;
7637
7638     case TRUNC_MOD_EXPR:
7639     case FLOOR_MOD_EXPR:
7640       if (skip_evaluation == 0 && integer_zerop (op1))
7641         warning (OPT_Wdiv_by_zero, "division by zero");
7642
7643       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7644         {
7645           /* Although it would be tempting to shorten always here, that loses
7646              on some targets, since the modulo instruction is undefined if the
7647              quotient can't be represented in the computation mode.  We shorten
7648              only if unsigned or if dividing by something we know != -1.  */
7649           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7650                      || (TREE_CODE (op1) == INTEGER_CST
7651                          && !integer_all_onesp (op1)));
7652           common = 1;
7653         }
7654       break;
7655
7656     case TRUTH_ANDIF_EXPR:
7657     case TRUTH_ORIF_EXPR:
7658     case TRUTH_AND_EXPR:
7659     case TRUTH_OR_EXPR:
7660     case TRUTH_XOR_EXPR:
7661       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7662            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7663           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7664               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7665         {
7666           /* Result of these operations is always an int,
7667              but that does not mean the operands should be
7668              converted to ints!  */
7669           result_type = integer_type_node;
7670           op0 = c_common_truthvalue_conversion (op0);
7671           op1 = c_common_truthvalue_conversion (op1);
7672           converted = 1;
7673         }
7674       break;
7675
7676       /* Shift operations: result has same type as first operand;
7677          always convert second operand to int.
7678          Also set SHORT_SHIFT if shifting rightward.  */
7679
7680     case RSHIFT_EXPR:
7681       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7682         {
7683           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7684             {
7685               if (tree_int_cst_sgn (op1) < 0)
7686                 warning (0, "right shift count is negative");
7687               else
7688                 {
7689                   if (!integer_zerop (op1))
7690                     short_shift = 1;
7691
7692                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7693                     warning (0, "right shift count >= width of type");
7694                 }
7695             }
7696
7697           /* Use the type of the value to be shifted.  */
7698           result_type = type0;
7699           /* Convert the shift-count to an integer, regardless of size
7700              of value being shifted.  */
7701           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7702             op1 = convert (integer_type_node, op1);
7703           /* Avoid converting op1 to result_type later.  */
7704           converted = 1;
7705         }
7706       break;
7707
7708     case LSHIFT_EXPR:
7709       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7710         {
7711           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7712             {
7713               if (tree_int_cst_sgn (op1) < 0)
7714                 warning (0, "left shift count is negative");
7715
7716               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7717                 warning (0, "left shift count >= width of type");
7718             }
7719
7720           /* Use the type of the value to be shifted.  */
7721           result_type = type0;
7722           /* Convert the shift-count to an integer, regardless of size
7723              of value being shifted.  */
7724           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7725             op1 = convert (integer_type_node, op1);
7726           /* Avoid converting op1 to result_type later.  */
7727           converted = 1;
7728         }
7729       break;
7730
7731     case EQ_EXPR:
7732     case NE_EXPR:
7733       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7734         warning (OPT_Wfloat_equal,
7735                  "comparing floating point with == or != is unsafe");
7736       /* Result of comparison is always int,
7737          but don't convert the args to int!  */
7738       build_type = integer_type_node;
7739       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7740            || code0 == COMPLEX_TYPE)
7741           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7742               || code1 == COMPLEX_TYPE))
7743         short_compare = 1;
7744       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7745         {
7746           tree tt0 = TREE_TYPE (type0);
7747           tree tt1 = TREE_TYPE (type1);
7748           /* Anything compares with void *.  void * compares with anything.
7749              Otherwise, the targets must be compatible
7750              and both must be object or both incomplete.  */
7751           if (comp_target_types (type0, type1))
7752             result_type = common_pointer_type (type0, type1);
7753           else if (VOID_TYPE_P (tt0))
7754             {
7755               /* op0 != orig_op0 detects the case of something
7756                  whose value is 0 but which isn't a valid null ptr const.  */
7757               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7758                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7759                 pedwarn ("ISO C forbids comparison of %<void *%>"
7760                          " with function pointer");
7761             }
7762           else if (VOID_TYPE_P (tt1))
7763             {
7764               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7765                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7766                 pedwarn ("ISO C forbids comparison of %<void *%>"
7767                          " with function pointer");
7768             }
7769           else
7770             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7771             if (!objc_ok)
7772               pedwarn ("comparison of distinct pointer types lacks a cast");
7773
7774           if (result_type == NULL_TREE)
7775             result_type = ptr_type_node;
7776         }
7777       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7778                && integer_zerop (op1))
7779         result_type = type0;
7780       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7781                && integer_zerop (op0))
7782         result_type = type1;
7783       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7784         {
7785           result_type = type0;
7786           pedwarn ("comparison between pointer and integer");
7787         }
7788       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7789         {
7790           result_type = type1;
7791           pedwarn ("comparison between pointer and integer");
7792         }
7793       break;
7794
7795     case LE_EXPR:
7796     case GE_EXPR:
7797     case LT_EXPR:
7798     case GT_EXPR:
7799       build_type = integer_type_node;
7800       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7801           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7802         short_compare = 1;
7803       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7804         {
7805           if (comp_target_types (type0, type1))
7806             {
7807               result_type = common_pointer_type (type0, type1);
7808               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7809                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7810                 pedwarn ("comparison of complete and incomplete pointers");
7811               else if (pedantic
7812                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7813                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7814             }
7815           else
7816             {
7817               result_type = ptr_type_node;
7818               pedwarn ("comparison of distinct pointer types lacks a cast");
7819             }
7820         }
7821       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7822                && integer_zerop (op1))
7823         {
7824           result_type = type0;
7825           if (pedantic || extra_warnings)
7826             pedwarn ("ordered comparison of pointer with integer zero");
7827         }
7828       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7829                && integer_zerop (op0))
7830         {
7831           result_type = type1;
7832           if (pedantic)
7833             pedwarn ("ordered comparison of pointer with integer zero");
7834         }
7835       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7836         {
7837           result_type = type0;
7838           pedwarn ("comparison between pointer and integer");
7839         }
7840       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7841         {
7842           result_type = type1;
7843           pedwarn ("comparison between pointer and integer");
7844         }
7845       break;
7846
7847     default:
7848       gcc_unreachable ();
7849     }
7850
7851   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7852     return error_mark_node;
7853
7854   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
7855       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
7856           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
7857                                                     TREE_TYPE (type1))))
7858     {
7859       binary_op_error (code);
7860       return error_mark_node;
7861     }
7862
7863   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7864        || code0 == VECTOR_TYPE)
7865       &&
7866       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7867        || code1 == VECTOR_TYPE))
7868     {
7869       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7870
7871       if (shorten || common || short_compare)
7872         result_type = c_common_type (type0, type1);
7873
7874       /* For certain operations (which identify themselves by shorten != 0)
7875          if both args were extended from the same smaller type,
7876          do the arithmetic in that type and then extend.
7877
7878          shorten !=0 and !=1 indicates a bitwise operation.
7879          For them, this optimization is safe only if
7880          both args are zero-extended or both are sign-extended.
7881          Otherwise, we might change the result.
7882          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7883          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7884
7885       if (shorten && none_complex)
7886         {
7887           int unsigned0, unsigned1;
7888           tree arg0 = get_narrower (op0, &unsigned0);
7889           tree arg1 = get_narrower (op1, &unsigned1);
7890           /* UNS is 1 if the operation to be done is an unsigned one.  */
7891           int uns = TYPE_UNSIGNED (result_type);
7892           tree type;
7893
7894           final_type = result_type;
7895
7896           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7897              but it *requires* conversion to FINAL_TYPE.  */
7898
7899           if ((TYPE_PRECISION (TREE_TYPE (op0))
7900                == TYPE_PRECISION (TREE_TYPE (arg0)))
7901               && TREE_TYPE (op0) != final_type)
7902             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7903           if ((TYPE_PRECISION (TREE_TYPE (op1))
7904                == TYPE_PRECISION (TREE_TYPE (arg1)))
7905               && TREE_TYPE (op1) != final_type)
7906             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7907
7908           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7909
7910           /* For bitwise operations, signedness of nominal type
7911              does not matter.  Consider only how operands were extended.  */
7912           if (shorten == -1)
7913             uns = unsigned0;
7914
7915           /* Note that in all three cases below we refrain from optimizing
7916              an unsigned operation on sign-extended args.
7917              That would not be valid.  */
7918
7919           /* Both args variable: if both extended in same way
7920              from same width, do it in that width.
7921              Do it unsigned if args were zero-extended.  */
7922           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7923                < TYPE_PRECISION (result_type))
7924               && (TYPE_PRECISION (TREE_TYPE (arg1))
7925                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7926               && unsigned0 == unsigned1
7927               && (unsigned0 || !uns))
7928             result_type
7929               = c_common_signed_or_unsigned_type
7930               (unsigned0, c_common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7931           else if (TREE_CODE (arg0) == INTEGER_CST
7932                    && (unsigned1 || !uns)
7933                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7934                        < TYPE_PRECISION (result_type))
7935                    && (type
7936                        = c_common_signed_or_unsigned_type (unsigned1,
7937                                                            TREE_TYPE (arg1)),
7938                        int_fits_type_p (arg0, type)))
7939             result_type = type;
7940           else if (TREE_CODE (arg1) == INTEGER_CST
7941                    && (unsigned0 || !uns)
7942                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7943                        < TYPE_PRECISION (result_type))
7944                    && (type
7945                        = c_common_signed_or_unsigned_type (unsigned0,
7946                                                            TREE_TYPE (arg0)),
7947                        int_fits_type_p (arg1, type)))
7948             result_type = type;
7949         }
7950
7951       /* Shifts can be shortened if shifting right.  */
7952
7953       if (short_shift)
7954         {
7955           int unsigned_arg;
7956           tree arg0 = get_narrower (op0, &unsigned_arg);
7957
7958           final_type = result_type;
7959
7960           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7961             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7962
7963           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7964               /* We can shorten only if the shift count is less than the
7965                  number of bits in the smaller type size.  */
7966               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7967               /* We cannot drop an unsigned shift after sign-extension.  */
7968               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7969             {
7970               /* Do an unsigned shift if the operand was zero-extended.  */
7971               result_type
7972                 = c_common_signed_or_unsigned_type (unsigned_arg,
7973                                                     TREE_TYPE (arg0));
7974               /* Convert value-to-be-shifted to that type.  */
7975               if (TREE_TYPE (op0) != result_type)
7976                 op0 = convert (result_type, op0);
7977               converted = 1;
7978             }
7979         }
7980
7981       /* Comparison operations are shortened too but differently.
7982          They identify themselves by setting short_compare = 1.  */
7983
7984       if (short_compare)
7985         {
7986           /* Don't write &op0, etc., because that would prevent op0
7987              from being kept in a register.
7988              Instead, make copies of the our local variables and
7989              pass the copies by reference, then copy them back afterward.  */
7990           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7991           enum tree_code xresultcode = resultcode;
7992           tree val
7993             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7994
7995           if (val != 0)
7996             return val;
7997
7998           op0 = xop0, op1 = xop1;
7999           converted = 1;
8000           resultcode = xresultcode;
8001
8002           if (warn_sign_compare && skip_evaluation == 0)
8003             {
8004               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8005               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8006               int unsignedp0, unsignedp1;
8007               tree primop0 = get_narrower (op0, &unsignedp0);
8008               tree primop1 = get_narrower (op1, &unsignedp1);
8009
8010               xop0 = orig_op0;
8011               xop1 = orig_op1;
8012               STRIP_TYPE_NOPS (xop0);
8013               STRIP_TYPE_NOPS (xop1);
8014
8015               /* Give warnings for comparisons between signed and unsigned
8016                  quantities that may fail.
8017
8018                  Do the checking based on the original operand trees, so that
8019                  casts will be considered, but default promotions won't be.
8020
8021                  Do not warn if the comparison is being done in a signed type,
8022                  since the signed type will only be chosen if it can represent
8023                  all the values of the unsigned type.  */
8024               if (!TYPE_UNSIGNED (result_type))
8025                 /* OK */;
8026               /* Do not warn if both operands are the same signedness.  */
8027               else if (op0_signed == op1_signed)
8028                 /* OK */;
8029               else
8030                 {
8031                   tree sop, uop;
8032
8033                   if (op0_signed)
8034                     sop = xop0, uop = xop1;
8035                   else
8036                     sop = xop1, uop = xop0;
8037
8038                   /* Do not warn if the signed quantity is an
8039                      unsuffixed integer literal (or some static
8040                      constant expression involving such literals or a
8041                      conditional expression involving such literals)
8042                      and it is non-negative.  */
8043                   if (tree_expr_nonnegative_p (sop))
8044                     /* OK */;
8045                   /* Do not warn if the comparison is an equality operation,
8046                      the unsigned quantity is an integral constant, and it
8047                      would fit in the result if the result were signed.  */
8048                   else if (TREE_CODE (uop) == INTEGER_CST
8049                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8050                            && int_fits_type_p
8051                            (uop, c_common_signed_type (result_type)))
8052                     /* OK */;
8053                   /* Do not warn if the unsigned quantity is an enumeration
8054                      constant and its maximum value would fit in the result
8055                      if the result were signed.  */
8056                   else if (TREE_CODE (uop) == INTEGER_CST
8057                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8058                            && int_fits_type_p
8059                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8060                             c_common_signed_type (result_type)))
8061                     /* OK */;
8062                   else
8063                     warning (0, "comparison between signed and unsigned");
8064                 }
8065
8066               /* Warn if two unsigned values are being compared in a size
8067                  larger than their original size, and one (and only one) is the
8068                  result of a `~' operator.  This comparison will always fail.
8069
8070                  Also warn if one operand is a constant, and the constant
8071                  does not have all bits set that are set in the ~ operand
8072                  when it is extended.  */
8073
8074               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8075                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8076                 {
8077                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8078                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8079                                             &unsignedp0);
8080                   else
8081                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8082                                             &unsignedp1);
8083
8084                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8085                     {
8086                       tree primop;
8087                       HOST_WIDE_INT constant, mask;
8088                       int unsignedp, bits;
8089
8090                       if (host_integerp (primop0, 0))
8091                         {
8092                           primop = primop1;
8093                           unsignedp = unsignedp1;
8094                           constant = tree_low_cst (primop0, 0);
8095                         }
8096                       else
8097                         {
8098                           primop = primop0;
8099                           unsignedp = unsignedp0;
8100                           constant = tree_low_cst (primop1, 0);
8101                         }
8102
8103                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8104                       if (bits < TYPE_PRECISION (result_type)
8105                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8106                         {
8107                           mask = (~(HOST_WIDE_INT) 0) << bits;
8108                           if ((mask & constant) != mask)
8109                             warning (0, "comparison of promoted ~unsigned with constant");
8110                         }
8111                     }
8112                   else if (unsignedp0 && unsignedp1
8113                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8114                                < TYPE_PRECISION (result_type))
8115                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8116                                < TYPE_PRECISION (result_type)))
8117                     warning (0, "comparison of promoted ~unsigned with unsigned");
8118                 }
8119             }
8120         }
8121     }
8122
8123   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8124      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8125      Then the expression will be built.
8126      It will be given type FINAL_TYPE if that is nonzero;
8127      otherwise, it will be given type RESULT_TYPE.  */
8128
8129   if (!result_type)
8130     {
8131       binary_op_error (code);
8132       return error_mark_node;
8133     }
8134
8135   if (!converted)
8136     {
8137       if (TREE_TYPE (op0) != result_type)
8138         op0 = convert (result_type, op0);
8139       if (TREE_TYPE (op1) != result_type)
8140         op1 = convert (result_type, op1);
8141
8142       /* This can happen if one operand has a vector type, and the other
8143          has a different type.  */
8144       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8145         return error_mark_node;
8146     }
8147
8148   if (build_type == NULL_TREE)
8149     build_type = result_type;
8150
8151   {
8152     tree result = build2 (resultcode, build_type, op0, op1);
8153
8154     /* Treat expressions in initializers specially as they can't trap.  */
8155     result = require_constant_value ? fold_initializer (result)
8156                                     : fold (result);
8157
8158     if (final_type != 0)
8159       result = convert (final_type, result);
8160     return result;
8161   }
8162 }
8163
8164
8165 /* Convert EXPR to be a truth-value, validating its type for this
8166    purpose.  */
8167
8168 tree
8169 c_objc_common_truthvalue_conversion (tree expr)
8170 {
8171   switch (TREE_CODE (TREE_TYPE (expr)))
8172     {
8173     case ARRAY_TYPE:
8174       error ("used array that cannot be converted to pointer where scalar is required");
8175       return error_mark_node;
8176
8177     case RECORD_TYPE:
8178       error ("used struct type value where scalar is required");
8179       return error_mark_node;
8180
8181     case UNION_TYPE:
8182       error ("used union type value where scalar is required");
8183       return error_mark_node;
8184
8185     case FUNCTION_TYPE:
8186       gcc_unreachable ();
8187
8188     default:
8189       break;
8190     }
8191
8192   /* ??? Should we also give an error for void and vectors rather than
8193      leaving those to give errors later?  */
8194   return c_common_truthvalue_conversion (expr);
8195 }
8196 \f
8197
8198 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8199    required.  */
8200
8201 tree
8202 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8203                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8204 {
8205   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8206     {
8207       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8208       /* Executing a compound literal inside a function reinitializes
8209          it.  */
8210       if (!TREE_STATIC (decl))
8211         *se = true;
8212       return decl;
8213     }
8214   else
8215     return expr;
8216 }