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, 2006, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  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 "c-lang.h"
  37 #include "tm_p.h"
  38 #include "flags.h"
  39 #include "output.h"
  40 #include "expr.h"
  41 #include "toplev.h"
  42 #include "intl.h"
  43 #include "ggc.h"
  44 #include "target.h"
  45 #include "tree-iterator.h"
  46 #include "gimple.h"
  47 #include "tree-flow.h"
  48
  49 /* Possible cases of implicit bad conversions.  Used to select
  50    diagnostic messages in convert_for_assignment.  */
  51 enum impl_conv {
  52   ic_argpass,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* Whether we are building a boolean conversion inside
  59    convert_for_assignment, or some other late binary operation.  If
  60    build_binary_op is called (from code shared with C++) in this case,
  61    then the operands have already been folded and the result will not
  62    be folded again, so C_MAYBE_CONST_EXPR should not be generated.  */
  63 bool in_late_binary_op;
  64
  65 /* The level of nesting inside "__alignof__".  */
  66 int in_alignof;
  67
  68 /* The level of nesting inside "sizeof".  */
  69 int in_sizeof;
  70
  71 /* The level of nesting inside "typeof".  */
  72 int in_typeof;
  73
  74 /* Nonzero if we've already printed a "missing braces around initializer"
  75    message within this initializer.  */
  76 static int missing_braces_mentioned;
  77
  78 static int require_constant_value;
  79 static int require_constant_elements;
  80
  81 static bool null_pointer_constant_p (const_tree);
  82 static tree qualify_type (tree, tree);
  83 static int tagged_types_tu_compatible_p (const_tree, const_tree, bool *);
  84 static int comp_target_types (location_t, tree, tree);
  85 static int function_types_compatible_p (const_tree, const_tree, bool *);
  86 static int type_lists_compatible_p (const_tree, const_tree, bool *);
  87 static tree lookup_field (tree, tree);
  88 static int convert_arguments (tree, VEC(tree,gc) *, VEC(tree,gc) *, tree,
  89                               tree);
  90 static tree pointer_diff (location_t, tree, tree);
  91 static tree convert_for_assignment (location_t, tree, tree, tree,
  92                                     enum impl_conv, bool, tree, tree, int);
  93 static tree valid_compound_expr_initializer (tree, tree);
  94 static void push_string (const char *);
  95 static void push_member_name (tree);
  96 static int spelling_length (void);
  97 static char *print_spelling (char *);
  98 static void warning_init (int, const char *);
  99 static tree digest_init (location_t, tree, tree, tree, bool, bool, int);
 100 static void output_init_element (tree, tree, bool, tree, tree, int, bool);
 101 static void output_pending_init_elements (int);
 102 static int set_designator (int);
 103 static void push_range_stack (tree);
 104 static void add_pending_init (tree, tree, tree, bool);
 105 static void set_nonincremental_init (void);
 106 static void set_nonincremental_init_from_string (tree);
 107 static tree find_init_member (tree);
 108 static void readonly_error (tree, enum lvalue_use);
 109 static void readonly_warning (tree, enum lvalue_use);
 110 static int lvalue_or_else (const_tree, enum lvalue_use);
 111 static void record_maybe_used_decl (tree);
 112 static int comptypes_internal (const_tree, const_tree, bool *);
 113 \f
 114 /* Return true if EXP is a null pointer constant, false otherwise.  */
 115
 116 static bool
 117 null_pointer_constant_p (const_tree expr)
 118 {
 119   /* This should really operate on c_expr structures, but they aren't
 120      yet available everywhere required.  */
 121   tree type = TREE_TYPE (expr);
 122   return (TREE_CODE (expr) == INTEGER_CST
 123           && !TREE_OVERFLOW (expr)
 124           && integer_zerop (expr)
 125           && (INTEGRAL_TYPE_P (type)
 126               || (TREE_CODE (type) == POINTER_TYPE
 127                   && VOID_TYPE_P (TREE_TYPE (type))
 128                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 129 }
 130
 131 /* EXPR may appear in an unevaluated part of an integer constant
 132    expression, but not in an evaluated part.  Wrap it in a
 133    C_MAYBE_CONST_EXPR, or mark it with TREE_OVERFLOW if it is just an
 134    INTEGER_CST and we cannot create a C_MAYBE_CONST_EXPR.  */
 135
 136 static tree
 137 note_integer_operands (tree expr)
 138 {
 139   tree ret;
 140   if (TREE_CODE (expr) == INTEGER_CST && in_late_binary_op)
 141     {
 142       ret = copy_node (expr);
 143       TREE_OVERFLOW (ret) = 1;
 144     }
 145   else
 146     {
 147       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (expr), NULL_TREE, expr);
 148       C_MAYBE_CONST_EXPR_INT_OPERANDS (ret) = 1;
 149     }
 150   return ret;
 151 }
 152
 153 /* Having checked whether EXPR may appear in an unevaluated part of an
 154    integer constant expression and found that it may, remove any
 155    C_MAYBE_CONST_EXPR noting this fact and return the resulting
 156    expression.  */
 157
 158 static inline tree
 159 remove_c_maybe_const_expr (tree expr)
 160 {
 161   if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR)
 162     return C_MAYBE_CONST_EXPR_EXPR (expr);
 163   else
 164     return expr;
 165 }
 166
 167 \f/* This is a cache to hold if two types are compatible or not.  */
 168
 169 struct tagged_tu_seen_cache {
 170   const struct tagged_tu_seen_cache * next;
 171   const_tree t1;
 172   const_tree t2;
 173   /* The return value of tagged_types_tu_compatible_p if we had seen
 174      these two types already.  */
 175   int val;
 176 };
 177
 178 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 179 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 180
 181 /* Do `exp = require_complete_type (exp);' to make sure exp
 182    does not have an incomplete type.  (That includes void types.)  */
 183
 184 tree
 185 require_complete_type (tree value)
 186 {
 187   tree type = TREE_TYPE (value);
 188
 189   if (value == error_mark_node || type == error_mark_node)
 190     return error_mark_node;
 191
 192   /* First, detect a valid value with a complete type.  */
 193   if (COMPLETE_TYPE_P (type))
 194     return value;
 195
 196   c_incomplete_type_error (value, type);
 197   return error_mark_node;
 198 }
 199
 200 /* Print an error message for invalid use of an incomplete type.
 201    VALUE is the expression that was used (or 0 if that isn't known)
 202    and TYPE is the type that was invalid.  */
 203
 204 void
 205 c_incomplete_type_error (const_tree value, const_tree type)
 206 {
 207   const char *type_code_string;
 208
 209   /* Avoid duplicate error message.  */
 210   if (TREE_CODE (type) == ERROR_MARK)
 211     return;
 212
 213   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 214                      || TREE_CODE (value) == PARM_DECL))
 215     error ("%qD has an incomplete type", value);
 216   else
 217     {
 218     retry:
 219       /* We must print an error message.  Be clever about what it says.  */
 220
 221       switch (TREE_CODE (type))
 222         {
 223         case RECORD_TYPE:
 224           type_code_string = "struct";
 225           break;
 226
 227         case UNION_TYPE:
 228           type_code_string = "union";
 229           break;
 230
 231         case ENUMERAL_TYPE:
 232           type_code_string = "enum";
 233           break;
 234
 235         case VOID_TYPE:
 236           error ("invalid use of void expression");
 237           return;
 238
 239         case ARRAY_TYPE:
 240           if (TYPE_DOMAIN (type))
 241             {
 242               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 243                 {
 244                   error ("invalid use of flexible array member");
 245                   return;
 246                 }
 247               type = TREE_TYPE (type);
 248               goto retry;
 249             }
 250           error ("invalid use of array with unspecified bounds");
 251           return;
 252
 253         default:
 254           gcc_unreachable ();
 255         }
 256
 257       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 258         error ("invalid use of undefined type %<%s %E%>",
 259                type_code_string, TYPE_NAME (type));
 260       else
 261         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 262         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 263     }
 264 }
 265
 266 /* Given a type, apply default promotions wrt unnamed function
 267    arguments and return the new type.  */
 268
 269 tree
 270 c_type_promotes_to (tree type)
 271 {
 272   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 273     return double_type_node;
 274
 275   if (c_promoting_integer_type_p (type))
 276     {
 277       /* Preserve unsignedness if not really getting any wider.  */
 278       if (TYPE_UNSIGNED (type)
 279           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 280         return unsigned_type_node;
 281       return integer_type_node;
 282     }
 283
 284   return type;
 285 }
 286
 287 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 288    as well as those of TYPE.  */
 289
 290 static tree
 291 qualify_type (tree type, tree like)
 292 {
 293   return c_build_qualified_type (type,
 294                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 295 }
 296
 297 /* Return true iff the given tree T is a variable length array.  */
 298
 299 bool
 300 c_vla_type_p (const_tree t)
 301 {
 302   if (TREE_CODE (t) == ARRAY_TYPE
 303       && C_TYPE_VARIABLE_SIZE (t))
 304     return true;
 305   return false;
 306 }
 307 \f
 308 /* Return the composite type of two compatible types.
 309
 310    We assume that comptypes has already been done and returned
 311    nonzero; if that isn't so, this may crash.  In particular, we
 312    assume that qualifiers match.  */
 313
 314 tree
 315 composite_type (tree t1, tree t2)
 316 {
 317   enum tree_code code1;
 318   enum tree_code code2;
 319   tree attributes;
 320
 321   /* Save time if the two types are the same.  */
 322
 323   if (t1 == t2) return t1;
 324
 325   /* If one type is nonsense, use the other.  */
 326   if (t1 == error_mark_node)
 327     return t2;
 328   if (t2 == error_mark_node)
 329     return t1;
 330
 331   code1 = TREE_CODE (t1);
 332   code2 = TREE_CODE (t2);
 333
 334   /* Merge the attributes.  */
 335   attributes = targetm.merge_type_attributes (t1, t2);
 336
 337   /* If one is an enumerated type and the other is the compatible
 338      integer type, the composite type might be either of the two
 339      (DR#013 question 3).  For consistency, use the enumerated type as
 340      the composite type.  */
 341
 342   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 343     return t1;
 344   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 345     return t2;
 346
 347   gcc_assert (code1 == code2);
 348
 349   switch (code1)
 350     {
 351     case POINTER_TYPE:
 352       /* For two pointers, do this recursively on the target type.  */
 353       {
 354         tree pointed_to_1 = TREE_TYPE (t1);
 355         tree pointed_to_2 = TREE_TYPE (t2);
 356         tree target = composite_type (pointed_to_1, pointed_to_2);
 357         t1 = build_pointer_type (target);
 358         t1 = build_type_attribute_variant (t1, attributes);
 359         return qualify_type (t1, t2);
 360       }
 361
 362     case ARRAY_TYPE:
 363       {
 364         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 365         int quals;
 366         tree unqual_elt;
 367         tree d1 = TYPE_DOMAIN (t1);
 368         tree d2 = TYPE_DOMAIN (t2);
 369         bool d1_variable, d2_variable;
 370         bool d1_zero, d2_zero;
 371         bool t1_complete, t2_complete;
 372
 373         /* We should not have any type quals on arrays at all.  */
 374         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 375
 376         t1_complete = COMPLETE_TYPE_P (t1);
 377         t2_complete = COMPLETE_TYPE_P (t2);
 378
 379         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 380         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 381
 382         d1_variable = (!d1_zero
 383                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 384                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 385         d2_variable = (!d2_zero
 386                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 387                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 388         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 389         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 390
 391         /* Save space: see if the result is identical to one of the args.  */
 392         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 393             && (d2_variable || d2_zero || !d1_variable))
 394           return build_type_attribute_variant (t1, attributes);
 395         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 396             && (d1_variable || d1_zero || !d2_variable))
 397           return build_type_attribute_variant (t2, attributes);
 398
 399         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 400           return build_type_attribute_variant (t1, attributes);
 401         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 402           return build_type_attribute_variant (t2, attributes);
 403
 404         /* Merge the element types, and have a size if either arg has
 405            one.  We may have qualifiers on the element types.  To set
 406            up TYPE_MAIN_VARIANT correctly, we need to form the
 407            composite of the unqualified types and add the qualifiers
 408            back at the end.  */
 409         quals = TYPE_QUALS (strip_array_types (elt));
 410         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 411         t1 = build_array_type (unqual_elt,
 412                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 413                                              && (d2_variable
 414                                                  || d2_zero
 415                                                  || !d1_variable))
 416                                             ? t1
 417                                             : t2));
 418         /* Ensure a composite type involving a zero-length array type
 419            is a zero-length type not an incomplete type.  */
 420         if (d1_zero && d2_zero
 421             && (t1_complete || t2_complete)
 422             && !COMPLETE_TYPE_P (t1))
 423           {
 424             TYPE_SIZE (t1) = bitsize_zero_node;
 425             TYPE_SIZE_UNIT (t1) = size_zero_node;
 426           }
 427         t1 = c_build_qualified_type (t1, quals);
 428         return build_type_attribute_variant (t1, attributes);
 429       }
 430
 431     case ENUMERAL_TYPE:
 432     case RECORD_TYPE:
 433     case UNION_TYPE:
 434       if (attributes != NULL)
 435         {
 436           /* Try harder not to create a new aggregate type.  */
 437           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 438             return t1;
 439           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 440             return t2;
 441         }
 442       return build_type_attribute_variant (t1, attributes);
 443
 444     case FUNCTION_TYPE:
 445       /* Function types: prefer the one that specified arg types.
 446          If both do, merge the arg types.  Also merge the return types.  */
 447       {
 448         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 449         tree p1 = TYPE_ARG_TYPES (t1);
 450         tree p2 = TYPE_ARG_TYPES (t2);
 451         int len;
 452         tree newargs, n;
 453         int i;
 454
 455         /* Save space: see if the result is identical to one of the args.  */
 456         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 457           return build_type_attribute_variant (t1, attributes);
 458         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 459           return build_type_attribute_variant (t2, attributes);
 460
 461         /* Simple way if one arg fails to specify argument types.  */
 462         if (TYPE_ARG_TYPES (t1) == 0)
 463          {
 464             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 465             t1 = build_type_attribute_variant (t1, attributes);
 466             return qualify_type (t1, t2);
 467          }
 468         if (TYPE_ARG_TYPES (t2) == 0)
 469          {
 470            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 471            t1 = build_type_attribute_variant (t1, attributes);
 472            return qualify_type (t1, t2);
 473          }
 474
 475         /* If both args specify argument types, we must merge the two
 476            lists, argument by argument.  */
 477         /* Tell global_bindings_p to return false so that variable_size
 478            doesn't die on VLAs in parameter types.  */
 479         c_override_global_bindings_to_false = true;
 480
 481         len = list_length (p1);
 482         newargs = 0;
 483
 484         for (i = 0; i < len; i++)
 485           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 486
 487         n = newargs;
 488
 489         for (; p1;
 490              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 491           {
 492             /* A null type means arg type is not specified.
 493                Take whatever the other function type has.  */
 494             if (TREE_VALUE (p1) == 0)
 495               {
 496                 TREE_VALUE (n) = TREE_VALUE (p2);
 497                 goto parm_done;
 498               }
 499             if (TREE_VALUE (p2) == 0)
 500               {
 501                 TREE_VALUE (n) = TREE_VALUE (p1);
 502                 goto parm_done;
 503               }
 504
 505             /* Given  wait (union {union wait *u; int *i} *)
 506                and  wait (union wait *),
 507                prefer  union wait *  as type of parm.  */
 508             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 509                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 510               {
 511                 tree memb;
 512                 tree mv2 = TREE_VALUE (p2);
 513                 if (mv2 && mv2 != error_mark_node
 514                     && TREE_CODE (mv2) != ARRAY_TYPE)
 515                   mv2 = TYPE_MAIN_VARIANT (mv2);
 516                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 517                      memb; memb = TREE_CHAIN (memb))
 518                   {
 519                     tree mv3 = TREE_TYPE (memb);
 520                     if (mv3 && mv3 != error_mark_node
 521                         && TREE_CODE (mv3) != ARRAY_TYPE)
 522                       mv3 = TYPE_MAIN_VARIANT (mv3);
 523                     if (comptypes (mv3, mv2))
 524                       {
 525                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 526                                                          TREE_VALUE (p2));
 527                         pedwarn (input_location, OPT_pedantic,
 528                                  "function types not truly compatible in ISO C");
 529                         goto parm_done;
 530                       }
 531                   }
 532               }
 533             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 534                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 535               {
 536                 tree memb;
 537                 tree mv1 = TREE_VALUE (p1);
 538                 if (mv1 && mv1 != error_mark_node
 539                     && TREE_CODE (mv1) != ARRAY_TYPE)
 540                   mv1 = TYPE_MAIN_VARIANT (mv1);
 541                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 542                      memb; memb = TREE_CHAIN (memb))
 543                   {
 544                     tree mv3 = TREE_TYPE (memb);
 545                     if (mv3 && mv3 != error_mark_node
 546                         && TREE_CODE (mv3) != ARRAY_TYPE)
 547                       mv3 = TYPE_MAIN_VARIANT (mv3);
 548                     if (comptypes (mv3, mv1))
 549                       {
 550                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 551                                                          TREE_VALUE (p1));
 552                         pedwarn (input_location, OPT_pedantic,
 553                                  "function types not truly compatible in ISO C");
 554                         goto parm_done;
 555                       }
 556                   }
 557               }
 558             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 559           parm_done: ;
 560           }
 561
 562         c_override_global_bindings_to_false = false;
 563         t1 = build_function_type (valtype, newargs);
 564         t1 = qualify_type (t1, t2);
 565         /* ... falls through ...  */
 566       }
 567
 568     default:
 569       return build_type_attribute_variant (t1, attributes);
 570     }
 571
 572 }
 573
 574 /* Return the type of a conditional expression between pointers to
 575    possibly differently qualified versions of compatible types.
 576
 577    We assume that comp_target_types has already been done and returned
 578    nonzero; if that isn't so, this may crash.  */
 579
 580 static tree
 581 common_pointer_type (tree t1, tree t2)
 582 {
 583   tree attributes;
 584   tree pointed_to_1, mv1;
 585   tree pointed_to_2, mv2;
 586   tree target;
 587   unsigned target_quals;
 588
 589   /* Save time if the two types are the same.  */
 590
 591   if (t1 == t2) return t1;
 592
 593   /* If one type is nonsense, use the other.  */
 594   if (t1 == error_mark_node)
 595     return t2;
 596   if (t2 == error_mark_node)
 597     return t1;
 598
 599   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 600               && TREE_CODE (t2) == POINTER_TYPE);
 601
 602   /* Merge the attributes.  */
 603   attributes = targetm.merge_type_attributes (t1, t2);
 604
 605   /* Find the composite type of the target types, and combine the
 606      qualifiers of the two types' targets.  Do not lose qualifiers on
 607      array element types by taking the TYPE_MAIN_VARIANT.  */
 608   mv1 = pointed_to_1 = TREE_TYPE (t1);
 609   mv2 = pointed_to_2 = TREE_TYPE (t2);
 610   if (TREE_CODE (mv1) != ARRAY_TYPE)
 611     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 612   if (TREE_CODE (mv2) != ARRAY_TYPE)
 613     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 614   target = composite_type (mv1, mv2);
 615
 616   /* For function types do not merge const qualifiers, but drop them
 617      if used inconsistently.  The middle-end uses these to mark const
 618      and noreturn functions.  */
 619   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 620     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 621   else
 622     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 623   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 624   return build_type_attribute_variant (t1, attributes);
 625 }
 626
 627 /* Return the common type for two arithmetic types under the usual
 628    arithmetic conversions.  The default conversions have already been
 629    applied, and enumerated types converted to their compatible integer
 630    types.  The resulting type is unqualified and has no attributes.
 631
 632    This is the type for the result of most arithmetic operations
 633    if the operands have the given two types.  */
 634
 635 static tree
 636 c_common_type (tree t1, tree t2)
 637 {
 638   enum tree_code code1;
 639   enum tree_code code2;
 640
 641   /* If one type is nonsense, use the other.  */
 642   if (t1 == error_mark_node)
 643     return t2;
 644   if (t2 == error_mark_node)
 645     return t1;
 646
 647   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 648     t1 = TYPE_MAIN_VARIANT (t1);
 649
 650   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 651     t2 = TYPE_MAIN_VARIANT (t2);
 652
 653   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 654     t1 = build_type_attribute_variant (t1, NULL_TREE);
 655
 656   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 657     t2 = build_type_attribute_variant (t2, NULL_TREE);
 658
 659   /* Save time if the two types are the same.  */
 660
 661   if (t1 == t2) return t1;
 662
 663   code1 = TREE_CODE (t1);
 664   code2 = TREE_CODE (t2);
 665
 666   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 667               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 668               || code1 == INTEGER_TYPE);
 669   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 670               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 671               || code2 == INTEGER_TYPE);
 672
 673   /* When one operand is a decimal float type, the other operand cannot be
 674      a generic float type or a complex type.  We also disallow vector types
 675      here.  */
 676   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 677       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 678     {
 679       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 680         {
 681           error ("can%'t mix operands of decimal float and vector types");
 682           return error_mark_node;
 683         }
 684       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 685         {
 686           error ("can%'t mix operands of decimal float and complex types");
 687           return error_mark_node;
 688         }
 689       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 690         {
 691           error ("can%'t mix operands of decimal float and other float types");
 692           return error_mark_node;
 693         }
 694     }
 695
 696   /* If one type is a vector type, return that type.  (How the usual
 697      arithmetic conversions apply to the vector types extension is not
 698      precisely specified.)  */
 699   if (code1 == VECTOR_TYPE)
 700     return t1;
 701
 702   if (code2 == VECTOR_TYPE)
 703     return t2;
 704
 705   /* If one type is complex, form the common type of the non-complex
 706      components, then make that complex.  Use T1 or T2 if it is the
 707      required type.  */
 708   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 709     {
 710       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 711       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 712       tree subtype = c_common_type (subtype1, subtype2);
 713
 714       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 715         return t1;
 716       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 717         return t2;
 718       else
 719         return build_complex_type (subtype);
 720     }
 721
 722   /* If only one is real, use it as the result.  */
 723
 724   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 725     return t1;
 726
 727   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 728     return t2;
 729
 730   /* If both are real and either are decimal floating point types, use
 731      the decimal floating point type with the greater precision. */
 732
 733   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 734     {
 735       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 736           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 737         return dfloat128_type_node;
 738       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 739                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 740         return dfloat64_type_node;
 741       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 742                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 743         return dfloat32_type_node;
 744     }
 745
 746   /* Deal with fixed-point types.  */
 747   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 748     {
 749       unsigned int unsignedp = 0, satp = 0;
 750       enum machine_mode m1, m2;
 751       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 752
 753       m1 = TYPE_MODE (t1);
 754       m2 = TYPE_MODE (t2);
 755
 756       /* If one input type is saturating, the result type is saturating.  */
 757       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 758         satp = 1;
 759
 760       /* If both fixed-point types are unsigned, the result type is unsigned.
 761          When mixing fixed-point and integer types, follow the sign of the
 762          fixed-point type.
 763          Otherwise, the result type is signed.  */
 764       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 765            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 766           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 767               && TYPE_UNSIGNED (t1))
 768           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 769               && TYPE_UNSIGNED (t2)))
 770         unsignedp = 1;
 771
 772       /* The result type is signed.  */
 773       if (unsignedp == 0)
 774         {
 775           /* If the input type is unsigned, we need to convert to the
 776              signed type.  */
 777           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 778             {
 779               enum mode_class mclass = (enum mode_class) 0;
 780               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 781                 mclass = MODE_FRACT;
 782               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 783                 mclass = MODE_ACCUM;
 784               else
 785                 gcc_unreachable ();
 786               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 787             }
 788           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 789             {
 790               enum mode_class mclass = (enum mode_class) 0;
 791               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 792                 mclass = MODE_FRACT;
 793               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 794                 mclass = MODE_ACCUM;
 795               else
 796                 gcc_unreachable ();
 797               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 798             }
 799         }
 800
 801       if (code1 == FIXED_POINT_TYPE)
 802         {
 803           fbit1 = GET_MODE_FBIT (m1);
 804           ibit1 = GET_MODE_IBIT (m1);
 805         }
 806       else
 807         {
 808           fbit1 = 0;
 809           /* Signed integers need to subtract one sign bit.  */
 810           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 811         }
 812
 813       if (code2 == FIXED_POINT_TYPE)
 814         {
 815           fbit2 = GET_MODE_FBIT (m2);
 816           ibit2 = GET_MODE_IBIT (m2);
 817         }
 818       else
 819         {
 820           fbit2 = 0;
 821           /* Signed integers need to subtract one sign bit.  */
 822           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 823         }
 824
 825       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 826       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 827       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 828                                                  satp);
 829     }
 830
 831   /* Both real or both integers; use the one with greater precision.  */
 832
 833   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 834     return t1;
 835   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 836     return t2;
 837
 838   /* Same precision.  Prefer long longs to longs to ints when the
 839      same precision, following the C99 rules on integer type rank
 840      (which are equivalent to the C90 rules for C90 types).  */
 841
 842   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 843       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 844     return long_long_unsigned_type_node;
 845
 846   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 847       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 848     {
 849       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 850         return long_long_unsigned_type_node;
 851       else
 852         return long_long_integer_type_node;
 853     }
 854
 855   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 856       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 857     return long_unsigned_type_node;
 858
 859   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 860       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 861     {
 862       /* But preserve unsignedness from the other type,
 863          since long cannot hold all the values of an unsigned int.  */
 864       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 865         return long_unsigned_type_node;
 866       else
 867         return long_integer_type_node;
 868     }
 869
 870   /* Likewise, prefer long double to double even if same size.  */
 871   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 872       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 873     return long_double_type_node;
 874
 875   /* Otherwise prefer the unsigned one.  */
 876
 877   if (TYPE_UNSIGNED (t1))
 878     return t1;
 879   else
 880     return t2;
 881 }
 882 \f
 883 /* Wrapper around c_common_type that is used by c-common.c and other
 884    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 885    are allowed here and are converted to their compatible integer types.
 886    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 887    preferably a non-Boolean type as the common type.  */
 888 tree
 889 common_type (tree t1, tree t2)
 890 {
 891   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 892     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 893   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 894     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 895
 896   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 897   if (TREE_CODE (t1) == BOOLEAN_TYPE
 898       && TREE_CODE (t2) == BOOLEAN_TYPE)
 899     return boolean_type_node;
 900
 901   /* If either type is BOOLEAN_TYPE, then return the other.  */
 902   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 903     return t2;
 904   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 905     return t1;
 906
 907   return c_common_type (t1, t2);
 908 }
 909
 910 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 911    or various other operations.  Return 2 if they are compatible
 912    but a warning may be needed if you use them together.  */
 913
 914 int
 915 comptypes (tree type1, tree type2)
 916 {
 917   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 918   int val;
 919
 920   val = comptypes_internal (type1, type2, NULL);
 921   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 922
 923   return val;
 924 }
 925
 926 /* Like comptypes, but if it returns non-zero because enum and int are
 927    compatible, it sets *ENUM_AND_INT_P to true.  */
 928
 929 static int
 930 comptypes_check_enum_int (tree type1, tree type2, bool *enum_and_int_p)
 931 {
 932   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 933   int val;
 934
 935   val = comptypes_internal (type1, type2, enum_and_int_p);
 936   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 937
 938   return val;
 939 }
 940 \f
 941 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 942    or various other operations.  Return 2 if they are compatible
 943    but a warning may be needed if you use them together.  If
 944    ENUM_AND_INT_P is not NULL, and one type is an enum and the other a
 945    compatible integer type, then this sets *ENUM_AND_INT_P to true;
 946    *ENUM_AND_INT_P is never set to false.  This differs from
 947    comptypes, in that we don't free the seen types.  */
 948
 949 static int
 950 comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p)
 951 {
 952   const_tree t1 = type1;
 953   const_tree t2 = type2;
 954   int attrval, val;
 955
 956   /* Suppress errors caused by previously reported errors.  */
 957
 958   if (t1 == t2 || !t1 || !t2
 959       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 960     return 1;
 961
 962   /* If either type is the internal version of sizetype, return the
 963      language version.  */
 964   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 965       && TYPE_ORIG_SIZE_TYPE (t1))
 966     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 967
 968   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 969       && TYPE_ORIG_SIZE_TYPE (t2))
 970     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 971
 972
 973   /* Enumerated types are compatible with integer types, but this is
 974      not transitive: two enumerated types in the same translation unit
 975      are compatible with each other only if they are the same type.  */
 976
 977   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 978     {
 979       t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 980       if (enum_and_int_p != NULL && TREE_CODE (t2) != VOID_TYPE)
 981         *enum_and_int_p = true;
 982     }
 983   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 984     {
 985       t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 986       if (enum_and_int_p != NULL && TREE_CODE (t1) != VOID_TYPE)
 987         *enum_and_int_p = true;
 988     }
 989
 990   if (t1 == t2)
 991     return 1;
 992
 993   /* Different classes of types can't be compatible.  */
 994
 995   if (TREE_CODE (t1) != TREE_CODE (t2))
 996     return 0;
 997
 998   /* Qualifiers must match. C99 6.7.3p9 */
 999
1000   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
1001     return 0;
1002
1003   /* Allow for two different type nodes which have essentially the same
1004      definition.  Note that we already checked for equality of the type
1005      qualifiers (just above).  */
1006
1007   if (TREE_CODE (t1) != ARRAY_TYPE
1008       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
1009     return 1;
1010
1011   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1012   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
1013      return 0;
1014
1015   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1016   val = 0;
1017
1018   switch (TREE_CODE (t1))
1019     {
1020     case POINTER_TYPE:
1021       /* Do not remove mode or aliasing information.  */
1022       if (TYPE_MODE (t1) != TYPE_MODE (t2)
1023           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
1024         break;
1025       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
1026              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1027                                        enum_and_int_p));
1028       break;
1029
1030     case FUNCTION_TYPE:
1031       val = function_types_compatible_p (t1, t2, enum_and_int_p);
1032       break;
1033
1034     case ARRAY_TYPE:
1035       {
1036         tree d1 = TYPE_DOMAIN (t1);
1037         tree d2 = TYPE_DOMAIN (t2);
1038         bool d1_variable, d2_variable;
1039         bool d1_zero, d2_zero;
1040         val = 1;
1041
1042         /* Target types must match incl. qualifiers.  */
1043         if (TREE_TYPE (t1) != TREE_TYPE (t2)
1044             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1045                                                enum_and_int_p)))
1046           return 0;
1047
1048         /* Sizes must match unless one is missing or variable.  */
1049         if (d1 == 0 || d2 == 0 || d1 == d2)
1050           break;
1051
1052         d1_zero = !TYPE_MAX_VALUE (d1);
1053         d2_zero = !TYPE_MAX_VALUE (d2);
1054
1055         d1_variable = (!d1_zero
1056                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
1057                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
1058         d2_variable = (!d2_zero
1059                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
1060                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
1061         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
1062         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
1063
1064         if (d1_variable || d2_variable)
1065           break;
1066         if (d1_zero && d2_zero)
1067           break;
1068         if (d1_zero || d2_zero
1069             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
1070             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
1071           val = 0;
1072
1073         break;
1074       }
1075
1076     case ENUMERAL_TYPE:
1077     case RECORD_TYPE:
1078     case UNION_TYPE:
1079       if (val != 1 && !same_translation_unit_p (t1, t2))
1080         {
1081           tree a1 = TYPE_ATTRIBUTES (t1);
1082           tree a2 = TYPE_ATTRIBUTES (t2);
1083
1084           if (! attribute_list_contained (a1, a2)
1085               && ! attribute_list_contained (a2, a1))
1086             break;
1087
1088           if (attrval != 2)
1089             return tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
1090           val = tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
1091         }
1092       break;
1093
1094     case VECTOR_TYPE:
1095       val = (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1096              && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1097                                     enum_and_int_p));
1098       break;
1099
1100     default:
1101       break;
1102     }
1103   return attrval == 2 && val == 1 ? 2 : val;
1104 }
1105
1106 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1107    ignoring their qualifiers.  */
1108
1109 static int
1110 comp_target_types (location_t location, tree ttl, tree ttr)
1111 {
1112   int val;
1113   tree mvl, mvr;
1114   bool enum_and_int_p;
1115
1116   /* Do not lose qualifiers on element types of array types that are
1117      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1118   mvl = TREE_TYPE (ttl);
1119   mvr = TREE_TYPE (ttr);
1120   if (TREE_CODE (mvl) != ARRAY_TYPE)
1121     mvl = TYPE_MAIN_VARIANT (mvl);
1122   if (TREE_CODE (mvr) != ARRAY_TYPE)
1123     mvr = TYPE_MAIN_VARIANT (mvr);
1124   enum_and_int_p = false;
1125   val = comptypes_check_enum_int (mvl, mvr, &enum_and_int_p);
1126
1127   if (val == 2)
1128     pedwarn (location, OPT_pedantic, "types are not quite compatible");
1129
1130   if (val == 1 && enum_and_int_p && warn_cxx_compat)
1131     warning_at (location, OPT_Wc___compat,
1132                 "pointer target types incompatible in C++");
1133
1134   return val;
1135 }
1136 \f
1137 /* Subroutines of `comptypes'.  */
1138
1139 /* Determine whether two trees derive from the same translation unit.
1140    If the CONTEXT chain ends in a null, that tree's context is still
1141    being parsed, so if two trees have context chains ending in null,
1142    they're in the same translation unit.  */
1143 int
1144 same_translation_unit_p (const_tree t1, const_tree t2)
1145 {
1146   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1147     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1148       {
1149       case tcc_declaration:
1150         t1 = DECL_CONTEXT (t1); break;
1151       case tcc_type:
1152         t1 = TYPE_CONTEXT (t1); break;
1153       case tcc_exceptional:
1154         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1155       default: gcc_unreachable ();
1156       }
1157
1158   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1159     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1160       {
1161       case tcc_declaration:
1162         t2 = DECL_CONTEXT (t2); break;
1163       case tcc_type:
1164         t2 = TYPE_CONTEXT (t2); break;
1165       case tcc_exceptional:
1166         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1167       default: gcc_unreachable ();
1168       }
1169
1170   return t1 == t2;
1171 }
1172
1173 /* Allocate the seen two types, assuming that they are compatible. */
1174
1175 static struct tagged_tu_seen_cache *
1176 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1177 {
1178   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1179   tu->next = tagged_tu_seen_base;
1180   tu->t1 = t1;
1181   tu->t2 = t2;
1182
1183   tagged_tu_seen_base = tu;
1184
1185   /* The C standard says that two structures in different translation
1186      units are compatible with each other only if the types of their
1187      fields are compatible (among other things).  We assume that they
1188      are compatible until proven otherwise when building the cache.
1189      An example where this can occur is:
1190      struct a
1191      {
1192        struct a *next;
1193      };
1194      If we are comparing this against a similar struct in another TU,
1195      and did not assume they were compatible, we end up with an infinite
1196      loop.  */
1197   tu->val = 1;
1198   return tu;
1199 }
1200
1201 /* Free the seen types until we get to TU_TIL. */
1202
1203 static void
1204 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1205 {
1206   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1207   while (tu != tu_til)
1208     {
1209       const struct tagged_tu_seen_cache *const tu1
1210         = (const struct tagged_tu_seen_cache *) tu;
1211       tu = tu1->next;
1212       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1213     }
1214   tagged_tu_seen_base = tu_til;
1215 }
1216
1217 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1218    compatible.  If the two types are not the same (which has been
1219    checked earlier), this can only happen when multiple translation
1220    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1221    rules.  ENUM_AND_INT_P is as in comptypes_internal.  */
1222
1223 static int
1224 tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
1225                               bool *enum_and_int_p)
1226 {
1227   tree s1, s2;
1228   bool needs_warning = false;
1229
1230   /* We have to verify that the tags of the types are the same.  This
1231      is harder than it looks because this may be a typedef, so we have
1232      to go look at the original type.  It may even be a typedef of a
1233      typedef...
1234      In the case of compiler-created builtin structs the TYPE_DECL
1235      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1236   while (TYPE_NAME (t1)
1237          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1238          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1239     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1240
1241   while (TYPE_NAME (t2)
1242          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1243          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1244     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1245
1246   /* C90 didn't have the requirement that the two tags be the same.  */
1247   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1248     return 0;
1249
1250   /* C90 didn't say what happened if one or both of the types were
1251      incomplete; we choose to follow C99 rules here, which is that they
1252      are compatible.  */
1253   if (TYPE_SIZE (t1) == NULL
1254       || TYPE_SIZE (t2) == NULL)
1255     return 1;
1256
1257   {
1258     const struct tagged_tu_seen_cache * tts_i;
1259     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1260       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1261         return tts_i->val;
1262   }
1263
1264   switch (TREE_CODE (t1))
1265     {
1266     case ENUMERAL_TYPE:
1267       {
1268         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1269         /* Speed up the case where the type values are in the same order.  */
1270         tree tv1 = TYPE_VALUES (t1);
1271         tree tv2 = TYPE_VALUES (t2);
1272
1273         if (tv1 == tv2)
1274           {
1275             return 1;
1276           }
1277
1278         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1279           {
1280             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1281               break;
1282             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1283               {
1284                 tu->val = 0;
1285                 return 0;
1286               }
1287           }
1288
1289         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1290           {
1291             return 1;
1292           }
1293         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1294           {
1295             tu->val = 0;
1296             return 0;
1297           }
1298
1299         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1300           {
1301             tu->val = 0;
1302             return 0;
1303           }
1304
1305         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1306           {
1307             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1308             if (s2 == NULL
1309                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1310               {
1311                 tu->val = 0;
1312                 return 0;
1313               }
1314           }
1315         return 1;
1316       }
1317
1318     case UNION_TYPE:
1319       {
1320         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1321         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1322           {
1323             tu->val = 0;
1324             return 0;
1325           }
1326
1327         /*  Speed up the common case where the fields are in the same order. */
1328         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1329              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1330           {
1331             int result;
1332
1333             if (DECL_NAME (s1) != DECL_NAME (s2))
1334               break;
1335             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1336                                          enum_and_int_p);
1337
1338             if (result != 1 && !DECL_NAME (s1))
1339               break;
1340             if (result == 0)
1341               {
1342                 tu->val = 0;
1343                 return 0;
1344               }
1345             if (result == 2)
1346               needs_warning = true;
1347
1348             if (TREE_CODE (s1) == FIELD_DECL
1349                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1350                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1351               {
1352                 tu->val = 0;
1353                 return 0;
1354               }
1355           }
1356         if (!s1 && !s2)
1357           {
1358             tu->val = needs_warning ? 2 : 1;
1359             return tu->val;
1360           }
1361
1362         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1363           {
1364             bool ok = false;
1365
1366             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1367               if (DECL_NAME (s1) == DECL_NAME (s2))
1368                 {
1369                   int result;
1370
1371                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1372                                                enum_and_int_p);
1373
1374                   if (result != 1 && !DECL_NAME (s1))
1375                     continue;
1376                   if (result == 0)
1377                     {
1378                       tu->val = 0;
1379                       return 0;
1380                     }
1381                   if (result == 2)
1382                     needs_warning = true;
1383
1384                   if (TREE_CODE (s1) == FIELD_DECL
1385                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1386                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1387                     break;
1388
1389                   ok = true;
1390                   break;
1391                 }
1392             if (!ok)
1393               {
1394                 tu->val = 0;
1395                 return 0;
1396               }
1397           }
1398         tu->val = needs_warning ? 2 : 10;
1399         return tu->val;
1400       }
1401
1402     case RECORD_TYPE:
1403       {
1404         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1405
1406         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1407              s1 && s2;
1408              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1409           {
1410             int result;
1411             if (TREE_CODE (s1) != TREE_CODE (s2)
1412                 || DECL_NAME (s1) != DECL_NAME (s2))
1413               break;
1414             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1415                                          enum_and_int_p);
1416             if (result == 0)
1417               break;
1418             if (result == 2)
1419               needs_warning = true;
1420
1421             if (TREE_CODE (s1) == FIELD_DECL
1422                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1423                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1424               break;
1425           }
1426         if (s1 && s2)
1427           tu->val = 0;
1428         else
1429           tu->val = needs_warning ? 2 : 1;
1430         return tu->val;
1431       }
1432
1433     default:
1434       gcc_unreachable ();
1435     }
1436 }
1437
1438 /* Return 1 if two function types F1 and F2 are compatible.
1439    If either type specifies no argument types,
1440    the other must specify a fixed number of self-promoting arg types.
1441    Otherwise, if one type specifies only the number of arguments,
1442    the other must specify that number of self-promoting arg types.
1443    Otherwise, the argument types must match.
1444    ENUM_AND_INT_P is as in comptypes_internal.  */
1445
1446 static int
1447 function_types_compatible_p (const_tree f1, const_tree f2,
1448                              bool *enum_and_int_p)
1449 {
1450   tree args1, args2;
1451   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1452   int val = 1;
1453   int val1;
1454   tree ret1, ret2;
1455
1456   ret1 = TREE_TYPE (f1);
1457   ret2 = TREE_TYPE (f2);
1458
1459   /* 'volatile' qualifiers on a function's return type used to mean
1460      the function is noreturn.  */
1461   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1462     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1463   if (TYPE_VOLATILE (ret1))
1464     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1465                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1466   if (TYPE_VOLATILE (ret2))
1467     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1468                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1469   val = comptypes_internal (ret1, ret2, enum_and_int_p);
1470   if (val == 0)
1471     return 0;
1472
1473   args1 = TYPE_ARG_TYPES (f1);
1474   args2 = TYPE_ARG_TYPES (f2);
1475
1476   /* An unspecified parmlist matches any specified parmlist
1477      whose argument types don't need default promotions.  */
1478
1479   if (args1 == 0)
1480     {
1481       if (!self_promoting_args_p (args2))
1482         return 0;
1483       /* If one of these types comes from a non-prototype fn definition,
1484          compare that with the other type's arglist.
1485          If they don't match, ask for a warning (but no error).  */
1486       if (TYPE_ACTUAL_ARG_TYPES (f1)
1487           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1),
1488                                            enum_and_int_p))
1489         val = 2;
1490       return val;
1491     }
1492   if (args2 == 0)
1493     {
1494       if (!self_promoting_args_p (args1))
1495         return 0;
1496       if (TYPE_ACTUAL_ARG_TYPES (f2)
1497           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2),
1498                                            enum_and_int_p))
1499         val = 2;
1500       return val;
1501     }
1502
1503   /* Both types have argument lists: compare them and propagate results.  */
1504   val1 = type_lists_compatible_p (args1, args2, enum_and_int_p);
1505   return val1 != 1 ? val1 : val;
1506 }
1507
1508 /* Check two lists of types for compatibility, returning 0 for
1509    incompatible, 1 for compatible, or 2 for compatible with
1510    warning.  ENUM_AND_INT_P is as in comptypes_internal.  */
1511
1512 static int
1513 type_lists_compatible_p (const_tree args1, const_tree args2,
1514                          bool *enum_and_int_p)
1515 {
1516   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1517   int val = 1;
1518   int newval = 0;
1519
1520   while (1)
1521     {
1522       tree a1, mv1, a2, mv2;
1523       if (args1 == 0 && args2 == 0)
1524         return val;
1525       /* If one list is shorter than the other,
1526          they fail to match.  */
1527       if (args1 == 0 || args2 == 0)
1528         return 0;
1529       mv1 = a1 = TREE_VALUE (args1);
1530       mv2 = a2 = TREE_VALUE (args2);
1531       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1532         mv1 = TYPE_MAIN_VARIANT (mv1);
1533       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1534         mv2 = TYPE_MAIN_VARIANT (mv2);
1535       /* A null pointer instead of a type
1536          means there is supposed to be an argument
1537          but nothing is specified about what type it has.
1538          So match anything that self-promotes.  */
1539       if (a1 == 0)
1540         {
1541           if (c_type_promotes_to (a2) != a2)
1542             return 0;
1543         }
1544       else if (a2 == 0)
1545         {
1546           if (c_type_promotes_to (a1) != a1)
1547             return 0;
1548         }
1549       /* If one of the lists has an error marker, ignore this arg.  */
1550       else if (TREE_CODE (a1) == ERROR_MARK
1551                || TREE_CODE (a2) == ERROR_MARK)
1552         ;
1553       else if (!(newval = comptypes_internal (mv1, mv2, enum_and_int_p)))
1554         {
1555           /* Allow  wait (union {union wait *u; int *i} *)
1556              and  wait (union wait *)  to be compatible.  */
1557           if (TREE_CODE (a1) == UNION_TYPE
1558               && (TYPE_NAME (a1) == 0
1559                   || TYPE_TRANSPARENT_UNION (a1))
1560               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1561               && tree_int_cst_equal (TYPE_SIZE (a1),
1562                                      TYPE_SIZE (a2)))
1563             {
1564               tree memb;
1565               for (memb = TYPE_FIELDS (a1);
1566                    memb; memb = TREE_CHAIN (memb))
1567                 {
1568                   tree mv3 = TREE_TYPE (memb);
1569                   if (mv3 && mv3 != error_mark_node
1570                       && TREE_CODE (mv3) != ARRAY_TYPE)
1571                     mv3 = TYPE_MAIN_VARIANT (mv3);
1572                   if (comptypes_internal (mv3, mv2, enum_and_int_p))
1573                     break;
1574                 }
1575               if (memb == 0)
1576                 return 0;
1577             }
1578           else if (TREE_CODE (a2) == UNION_TYPE
1579                    && (TYPE_NAME (a2) == 0
1580                        || TYPE_TRANSPARENT_UNION (a2))
1581                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1582                    && tree_int_cst_equal (TYPE_SIZE (a2),
1583                                           TYPE_SIZE (a1)))
1584             {
1585               tree memb;
1586               for (memb = TYPE_FIELDS (a2);
1587                    memb; memb = TREE_CHAIN (memb))
1588                 {
1589                   tree mv3 = TREE_TYPE (memb);
1590                   if (mv3 && mv3 != error_mark_node
1591                       && TREE_CODE (mv3) != ARRAY_TYPE)
1592                     mv3 = TYPE_MAIN_VARIANT (mv3);
1593                   if (comptypes_internal (mv3, mv1, enum_and_int_p))
1594                     break;
1595                 }
1596               if (memb == 0)
1597                 return 0;
1598             }
1599           else
1600             return 0;
1601         }
1602
1603       /* comptypes said ok, but record if it said to warn.  */
1604       if (newval > val)
1605         val = newval;
1606
1607       args1 = TREE_CHAIN (args1);
1608       args2 = TREE_CHAIN (args2);
1609     }
1610 }
1611 \f
1612 /* Compute the size to increment a pointer by.  */
1613
1614 static tree
1615 c_size_in_bytes (const_tree type)
1616 {
1617   enum tree_code code = TREE_CODE (type);
1618
1619   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1620     return size_one_node;
1621
1622   if (!COMPLETE_OR_VOID_TYPE_P (type))
1623     {
1624       error ("arithmetic on pointer to an incomplete type");
1625       return size_one_node;
1626     }
1627
1628   /* Convert in case a char is more than one unit.  */
1629   return size_binop_loc (input_location, CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1630                          size_int (TYPE_PRECISION (char_type_node)
1631                                    / BITS_PER_UNIT));
1632 }
1633 \f
1634 /* Return either DECL or its known constant value (if it has one).  */
1635
1636 tree
1637 decl_constant_value (tree decl)
1638 {
1639   if (/* Don't change a variable array bound or initial value to a constant
1640          in a place where a variable is invalid.  Note that DECL_INITIAL
1641          isn't valid for a PARM_DECL.  */
1642       current_function_decl != 0
1643       && TREE_CODE (decl) != PARM_DECL
1644       && !TREE_THIS_VOLATILE (decl)
1645       && TREE_READONLY (decl)
1646       && DECL_INITIAL (decl) != 0
1647       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1648       /* This is invalid if initial value is not constant.
1649          If it has either a function call, a memory reference,
1650          or a variable, then re-evaluating it could give different results.  */
1651       && TREE_CONSTANT (DECL_INITIAL (decl))
1652       /* Check for cases where this is sub-optimal, even though valid.  */
1653       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1654     return DECL_INITIAL (decl);
1655   return decl;
1656 }
1657
1658 /* Convert the array expression EXP to a pointer.  */
1659 static tree
1660 array_to_pointer_conversion (location_t loc, tree exp)
1661 {
1662   tree orig_exp = exp;
1663   tree type = TREE_TYPE (exp);
1664   tree adr;
1665   tree restype = TREE_TYPE (type);
1666   tree ptrtype;
1667
1668   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1669
1670   STRIP_TYPE_NOPS (exp);
1671
1672   if (TREE_NO_WARNING (orig_exp))
1673     TREE_NO_WARNING (exp) = 1;
1674
1675   ptrtype = build_pointer_type (restype);
1676
1677   if (TREE_CODE (exp) == INDIRECT_REF)
1678     return convert (ptrtype, TREE_OPERAND (exp, 0));
1679
1680   adr = build_unary_op (loc, ADDR_EXPR, exp, 1);
1681   return convert (ptrtype, adr);
1682 }
1683
1684 /* Convert the function expression EXP to a pointer.  */
1685 static tree
1686 function_to_pointer_conversion (location_t loc, tree exp)
1687 {
1688   tree orig_exp = exp;
1689
1690   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1691
1692   STRIP_TYPE_NOPS (exp);
1693
1694   if (TREE_NO_WARNING (orig_exp))
1695     TREE_NO_WARNING (exp) = 1;
1696
1697   return build_unary_op (loc, ADDR_EXPR, exp, 0);
1698 }
1699
1700 /* Perform the default conversion of arrays and functions to pointers.
1701    Return the result of converting EXP.  For any other expression, just
1702    return EXP.
1703
1704    LOC is the location of the expression.  */
1705
1706 struct c_expr
1707 default_function_array_conversion (location_t loc, struct c_expr exp)
1708 {
1709   tree orig_exp = exp.value;
1710   tree type = TREE_TYPE (exp.value);
1711   enum tree_code code = TREE_CODE (type);
1712
1713   switch (code)
1714     {
1715     case ARRAY_TYPE:
1716       {
1717         bool not_lvalue = false;
1718         bool lvalue_array_p;
1719
1720         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1721                 || CONVERT_EXPR_P (exp.value))
1722                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1723           {
1724             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1725               not_lvalue = true;
1726             exp.value = TREE_OPERAND (exp.value, 0);
1727           }
1728
1729         if (TREE_NO_WARNING (orig_exp))
1730           TREE_NO_WARNING (exp.value) = 1;
1731
1732         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1733         if (!flag_isoc99 && !lvalue_array_p)
1734           {
1735             /* Before C99, non-lvalue arrays do not decay to pointers.
1736                Normally, using such an array would be invalid; but it can
1737                be used correctly inside sizeof or as a statement expression.
1738                Thus, do not give an error here; an error will result later.  */
1739             return exp;
1740           }
1741
1742         exp.value = array_to_pointer_conversion (loc, exp.value);
1743       }
1744       break;
1745     case FUNCTION_TYPE:
1746       exp.value = function_to_pointer_conversion (loc, exp.value);
1747       break;
1748     default:
1749       break;
1750     }
1751
1752   return exp;
1753 }
1754
1755
1756 /* EXP is an expression of integer type.  Apply the integer promotions
1757    to it and return the promoted value.  */
1758
1759 tree
1760 perform_integral_promotions (tree exp)
1761 {
1762   tree type = TREE_TYPE (exp);
1763   enum tree_code code = TREE_CODE (type);
1764
1765   gcc_assert (INTEGRAL_TYPE_P (type));
1766
1767   /* Normally convert enums to int,
1768      but convert wide enums to something wider.  */
1769   if (code == ENUMERAL_TYPE)
1770     {
1771       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1772                                           TYPE_PRECISION (integer_type_node)),
1773                                      ((TYPE_PRECISION (type)
1774                                        >= TYPE_PRECISION (integer_type_node))
1775                                       && TYPE_UNSIGNED (type)));
1776
1777       return convert (type, exp);
1778     }
1779
1780   /* ??? This should no longer be needed now bit-fields have their
1781      proper types.  */
1782   if (TREE_CODE (exp) == COMPONENT_REF
1783       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1784       /* If it's thinner than an int, promote it like a
1785          c_promoting_integer_type_p, otherwise leave it alone.  */
1786       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1787                                TYPE_PRECISION (integer_type_node)))
1788     return convert (integer_type_node, exp);
1789
1790   if (c_promoting_integer_type_p (type))
1791     {
1792       /* Preserve unsignedness if not really getting any wider.  */
1793       if (TYPE_UNSIGNED (type)
1794           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1795         return convert (unsigned_type_node, exp);
1796
1797       return convert (integer_type_node, exp);
1798     }
1799
1800   return exp;
1801 }
1802
1803
1804 /* Perform default promotions for C data used in expressions.
1805    Enumeral types or short or char are converted to int.
1806    In addition, manifest constants symbols are replaced by their values.  */
1807
1808 tree
1809 default_conversion (tree exp)
1810 {
1811   tree orig_exp;
1812   tree type = TREE_TYPE (exp);
1813   enum tree_code code = TREE_CODE (type);
1814   tree promoted_type;
1815
1816   /* Functions and arrays have been converted during parsing.  */
1817   gcc_assert (code != FUNCTION_TYPE);
1818   if (code == ARRAY_TYPE)
1819     return exp;
1820
1821   /* Constants can be used directly unless they're not loadable.  */
1822   if (TREE_CODE (exp) == CONST_DECL)
1823     exp = DECL_INITIAL (exp);
1824
1825   /* Strip no-op conversions.  */
1826   orig_exp = exp;
1827   STRIP_TYPE_NOPS (exp);
1828
1829   if (TREE_NO_WARNING (orig_exp))
1830     TREE_NO_WARNING (exp) = 1;
1831
1832   if (code == VOID_TYPE)
1833     {
1834       error ("void value not ignored as it ought to be");
1835       return error_mark_node;
1836     }
1837
1838   exp = require_complete_type (exp);
1839   if (exp == error_mark_node)
1840     return error_mark_node;
1841
1842   promoted_type = targetm.promoted_type (type);
1843   if (promoted_type)
1844     return convert (promoted_type, exp);
1845
1846   if (INTEGRAL_TYPE_P (type))
1847     return perform_integral_promotions (exp);
1848
1849   return exp;
1850 }
1851 \f
1852 /* Look up COMPONENT in a structure or union DECL.
1853
1854    If the component name is not found, returns NULL_TREE.  Otherwise,
1855    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1856    stepping down the chain to the component, which is in the last
1857    TREE_VALUE of the list.  Normally the list is of length one, but if
1858    the component is embedded within (nested) anonymous structures or
1859    unions, the list steps down the chain to the component.  */
1860
1861 static tree
1862 lookup_field (tree decl, tree component)
1863 {
1864   tree type = TREE_TYPE (decl);
1865   tree field;
1866
1867   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1868      to the field elements.  Use a binary search on this array to quickly
1869      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1870      will always be set for structures which have many elements.  */
1871
1872   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1873     {
1874       int bot, top, half;
1875       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1876
1877       field = TYPE_FIELDS (type);
1878       bot = 0;
1879       top = TYPE_LANG_SPECIFIC (type)->s->len;
1880       while (top - bot > 1)
1881         {
1882           half = (top - bot + 1) >> 1;
1883           field = field_array[bot+half];
1884
1885           if (DECL_NAME (field) == NULL_TREE)
1886             {
1887               /* Step through all anon unions in linear fashion.  */
1888               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1889                 {
1890                   field = field_array[bot++];
1891                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1892                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1893                     {
1894                       tree anon = lookup_field (field, component);
1895
1896                       if (anon)
1897                         return tree_cons (NULL_TREE, field, anon);
1898                     }
1899                 }
1900
1901               /* Entire record is only anon unions.  */
1902               if (bot > top)
1903                 return NULL_TREE;
1904
1905               /* Restart the binary search, with new lower bound.  */
1906               continue;
1907             }
1908
1909           if (DECL_NAME (field) == component)
1910             break;
1911           if (DECL_NAME (field) < component)
1912             bot += half;
1913           else
1914             top = bot + half;
1915         }
1916
1917       if (DECL_NAME (field_array[bot]) == component)
1918         field = field_array[bot];
1919       else if (DECL_NAME (field) != component)
1920         return NULL_TREE;
1921     }
1922   else
1923     {
1924       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1925         {
1926           if (DECL_NAME (field) == NULL_TREE
1927               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1928                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1929             {
1930               tree anon = lookup_field (field, component);
1931
1932               if (anon)
1933                 return tree_cons (NULL_TREE, field, anon);
1934             }
1935
1936           if (DECL_NAME (field) == component)
1937             break;
1938         }
1939
1940       if (field == NULL_TREE)
1941         return NULL_TREE;
1942     }
1943
1944   return tree_cons (NULL_TREE, field, NULL_TREE);
1945 }
1946
1947 /* Make an expression to refer to the COMPONENT field of structure or
1948    union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  LOC is the
1949    location of the COMPONENT_REF.  */
1950
1951 tree
1952 build_component_ref (location_t loc, tree datum, tree component)
1953 {
1954   tree type = TREE_TYPE (datum);
1955   enum tree_code code = TREE_CODE (type);
1956   tree field = NULL;
1957   tree ref;
1958   bool datum_lvalue = lvalue_p (datum);
1959
1960   if (!objc_is_public (datum, component))
1961     return error_mark_node;
1962
1963   /* See if there is a field or component with name COMPONENT.  */
1964
1965   if (code == RECORD_TYPE || code == UNION_TYPE)
1966     {
1967       if (!COMPLETE_TYPE_P (type))
1968         {
1969           c_incomplete_type_error (NULL_TREE, type);
1970           return error_mark_node;
1971         }
1972
1973       field = lookup_field (datum, component);
1974
1975       if (!field)
1976         {
1977           error_at (loc, "%qT has no member named %qE", type, component);
1978           return error_mark_node;
1979         }
1980
1981       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1982          This might be better solved in future the way the C++ front
1983          end does it - by giving the anonymous entities each a
1984          separate name and type, and then have build_component_ref
1985          recursively call itself.  We can't do that here.  */
1986       do
1987         {
1988           tree subdatum = TREE_VALUE (field);
1989           int quals;
1990           tree subtype;
1991           bool use_datum_quals;
1992
1993           if (TREE_TYPE (subdatum) == error_mark_node)
1994             return error_mark_node;
1995
1996           /* If this is an rvalue, it does not have qualifiers in C
1997              standard terms and we must avoid propagating such
1998              qualifiers down to a non-lvalue array that is then
1999              converted to a pointer.  */
2000           use_datum_quals = (datum_lvalue
2001                              || TREE_CODE (TREE_TYPE (subdatum)) != ARRAY_TYPE);
2002
2003           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
2004           if (use_datum_quals)
2005             quals |= TYPE_QUALS (TREE_TYPE (datum));
2006           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
2007
2008           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
2009                         NULL_TREE);
2010           SET_EXPR_LOCATION (ref, loc);
2011           if (TREE_READONLY (subdatum)
2012               || (use_datum_quals && TREE_READONLY (datum)))
2013             TREE_READONLY (ref) = 1;
2014           if (TREE_THIS_VOLATILE (subdatum)
2015               || (use_datum_quals && TREE_THIS_VOLATILE (datum)))
2016             TREE_THIS_VOLATILE (ref) = 1;
2017
2018           if (TREE_DEPRECATED (subdatum))
2019             warn_deprecated_use (subdatum, NULL_TREE);
2020
2021           datum = ref;
2022
2023           field = TREE_CHAIN (field);
2024         }
2025       while (field);
2026
2027       return ref;
2028     }
2029   else if (code != ERROR_MARK)
2030     error_at (loc,
2031               "request for member %qE in something not a structure or union",
2032               component);
2033
2034   return error_mark_node;
2035 }
2036 \f
2037 /* Given an expression PTR for a pointer, return an expression
2038    for the value pointed to.
2039    ERRORSTRING is the name of the operator to appear in error messages.
2040
2041    LOC is the location to use for the generated tree.  */
2042
2043 tree
2044 build_indirect_ref (location_t loc, tree ptr, const char *errorstring)
2045 {
2046   tree pointer = default_conversion (ptr);
2047   tree type = TREE_TYPE (pointer);
2048   tree ref;
2049
2050   if (TREE_CODE (type) == POINTER_TYPE)
2051     {
2052       if (CONVERT_EXPR_P (pointer)
2053           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
2054         {
2055           /* If a warning is issued, mark it to avoid duplicates from
2056              the backend.  This only needs to be done at
2057              warn_strict_aliasing > 2.  */
2058           if (warn_strict_aliasing > 2)
2059             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
2060                                          type, TREE_OPERAND (pointer, 0)))
2061               TREE_NO_WARNING (pointer) = 1;
2062         }
2063
2064       if (TREE_CODE (pointer) == ADDR_EXPR
2065           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
2066               == TREE_TYPE (type)))
2067         {
2068           ref = TREE_OPERAND (pointer, 0);
2069           protected_set_expr_location (ref, loc);
2070           return ref;
2071         }
2072       else
2073         {
2074           tree t = TREE_TYPE (type);
2075
2076           ref = build1 (INDIRECT_REF, t, pointer);
2077
2078           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2079             {
2080               error_at (loc, "dereferencing pointer to incomplete type");
2081               return error_mark_node;
2082             }
2083           if (VOID_TYPE_P (t) && c_inhibit_evaluation_warnings == 0)
2084             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2085
2086           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2087              so that we get the proper error message if the result is used
2088              to assign to.  Also, &* is supposed to be a no-op.
2089              And ANSI C seems to specify that the type of the result
2090              should be the const type.  */
2091           /* A de-reference of a pointer to const is not a const.  It is valid
2092              to change it via some other pointer.  */
2093           TREE_READONLY (ref) = TYPE_READONLY (t);
2094           TREE_SIDE_EFFECTS (ref)
2095             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2096           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2097           protected_set_expr_location (ref, loc);
2098           return ref;
2099         }
2100     }
2101   else if (TREE_CODE (pointer) != ERROR_MARK)
2102     error_at (loc,
2103               "invalid type argument of %qs (have %qT)", errorstring, type);
2104   return error_mark_node;
2105 }
2106
2107 /* This handles expressions of the form "a[i]", which denotes
2108    an array reference.
2109
2110    This is logically equivalent in C to *(a+i), but we may do it differently.
2111    If A is a variable or a member, we generate a primitive ARRAY_REF.
2112    This avoids forcing the array out of registers, and can work on
2113    arrays that are not lvalues (for example, members of structures returned
2114    by functions).
2115
2116    LOC is the location to use for the returned expression.  */
2117
2118 tree
2119 build_array_ref (location_t loc, tree array, tree index)
2120 {
2121   tree ret;
2122   bool swapped = false;
2123   if (TREE_TYPE (array) == error_mark_node
2124       || TREE_TYPE (index) == error_mark_node)
2125     return error_mark_node;
2126
2127   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2128       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2129     {
2130       tree temp;
2131       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2132           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2133         {
2134           error_at (loc, "subscripted value is neither array nor pointer");
2135           return error_mark_node;
2136         }
2137       temp = array;
2138       array = index;
2139       index = temp;
2140       swapped = true;
2141     }
2142
2143   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2144     {
2145       error_at (loc, "array subscript is not an integer");
2146       return error_mark_node;
2147     }
2148
2149   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2150     {
2151       error_at (loc, "subscripted value is pointer to function");
2152       return error_mark_node;
2153     }
2154
2155   /* ??? Existing practice has been to warn only when the char
2156      index is syntactically the index, not for char[array].  */
2157   if (!swapped)
2158      warn_array_subscript_with_type_char (index);
2159
2160   /* Apply default promotions *after* noticing character types.  */
2161   index = default_conversion (index);
2162
2163   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2164
2165   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2166     {
2167       tree rval, type;
2168
2169       /* An array that is indexed by a non-constant
2170          cannot be stored in a register; we must be able to do
2171          address arithmetic on its address.
2172          Likewise an array of elements of variable size.  */
2173       if (TREE_CODE (index) != INTEGER_CST
2174           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2175               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2176         {
2177           if (!c_mark_addressable (array))
2178             return error_mark_node;
2179         }
2180       /* An array that is indexed by a constant value which is not within
2181          the array bounds cannot be stored in a register either; because we
2182          would get a crash in store_bit_field/extract_bit_field when trying
2183          to access a non-existent part of the register.  */
2184       if (TREE_CODE (index) == INTEGER_CST
2185           && TYPE_DOMAIN (TREE_TYPE (array))
2186           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2187         {
2188           if (!c_mark_addressable (array))
2189             return error_mark_node;
2190         }
2191
2192       if (pedantic)
2193         {
2194           tree foo = array;
2195           while (TREE_CODE (foo) == COMPONENT_REF)
2196             foo = TREE_OPERAND (foo, 0);
2197           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2198             pedwarn (loc, OPT_pedantic,
2199                      "ISO C forbids subscripting %<register%> array");
2200           else if (!flag_isoc99 && !lvalue_p (foo))
2201             pedwarn (loc, OPT_pedantic,
2202                      "ISO C90 forbids subscripting non-lvalue array");
2203         }
2204
2205       type = TREE_TYPE (TREE_TYPE (array));
2206       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2207       /* Array ref is const/volatile if the array elements are
2208          or if the array is.  */
2209       TREE_READONLY (rval)
2210         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2211             | TREE_READONLY (array));
2212       TREE_SIDE_EFFECTS (rval)
2213         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2214             | TREE_SIDE_EFFECTS (array));
2215       TREE_THIS_VOLATILE (rval)
2216         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2217             /* This was added by rms on 16 Nov 91.
2218                It fixes  vol struct foo *a;  a->elts[1]
2219                in an inline function.
2220                Hope it doesn't break something else.  */
2221             | TREE_THIS_VOLATILE (array));
2222       ret = require_complete_type (rval);
2223       protected_set_expr_location (ret, loc);
2224       return ret;
2225     }
2226   else
2227     {
2228       tree ar = default_conversion (array);
2229
2230       if (ar == error_mark_node)
2231         return ar;
2232
2233       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2234       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2235
2236       return build_indirect_ref
2237         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2238          "array indexing");
2239     }
2240 }
2241 \f
2242 /* Build an external reference to identifier ID.  FUN indicates
2243    whether this will be used for a function call.  LOC is the source
2244    location of the identifier.  This sets *TYPE to the type of the
2245    identifier, which is not the same as the type of the returned value
2246    for CONST_DECLs defined as enum constants.  If the type of the
2247    identifier is not available, *TYPE is set to NULL.  */
2248 tree
2249 build_external_ref (location_t loc, tree id, int fun, tree *type)
2250 {
2251   tree ref;
2252   tree decl = lookup_name (id);
2253
2254   /* In Objective-C, an instance variable (ivar) may be preferred to
2255      whatever lookup_name() found.  */
2256   decl = objc_lookup_ivar (decl, id);
2257
2258   *type = NULL;
2259   if (decl && decl != error_mark_node)
2260     {
2261       ref = decl;
2262       *type = TREE_TYPE (ref);
2263     }
2264   else if (fun)
2265     /* Implicit function declaration.  */
2266     ref = implicitly_declare (loc, id);
2267   else if (decl == error_mark_node)
2268     /* Don't complain about something that's already been
2269        complained about.  */
2270     return error_mark_node;
2271   else
2272     {
2273       undeclared_variable (loc, id);
2274       return error_mark_node;
2275     }
2276
2277   if (TREE_TYPE (ref) == error_mark_node)
2278     return error_mark_node;
2279
2280   if (TREE_DEPRECATED (ref))
2281     warn_deprecated_use (ref, NULL_TREE);
2282
2283   /* Recursive call does not count as usage.  */
2284   if (ref != current_function_decl)
2285     {
2286       TREE_USED (ref) = 1;
2287     }
2288
2289   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2290     {
2291       if (!in_sizeof && !in_typeof)
2292         C_DECL_USED (ref) = 1;
2293       else if (DECL_INITIAL (ref) == 0
2294                && DECL_EXTERNAL (ref)
2295                && !TREE_PUBLIC (ref))
2296         record_maybe_used_decl (ref);
2297     }
2298
2299   if (TREE_CODE (ref) == CONST_DECL)
2300     {
2301       used_types_insert (TREE_TYPE (ref));
2302
2303       if (warn_cxx_compat
2304           && TREE_CODE (TREE_TYPE (ref)) == ENUMERAL_TYPE
2305           && C_TYPE_DEFINED_IN_STRUCT (TREE_TYPE (ref)))
2306         {
2307           warning_at (loc, OPT_Wc___compat,
2308                       ("enum constant defined in struct or union "
2309                        "is not visible in C++"));
2310           inform (DECL_SOURCE_LOCATION (ref), "enum constant defined here");
2311         }
2312
2313       ref = DECL_INITIAL (ref);
2314       TREE_CONSTANT (ref) = 1;
2315     }
2316   else if (current_function_decl != 0
2317            && !DECL_FILE_SCOPE_P (current_function_decl)
2318            && (TREE_CODE (ref) == VAR_DECL
2319                || TREE_CODE (ref) == PARM_DECL
2320                || TREE_CODE (ref) == FUNCTION_DECL))
2321     {
2322       tree context = decl_function_context (ref);
2323
2324       if (context != 0 && context != current_function_decl)
2325         DECL_NONLOCAL (ref) = 1;
2326     }
2327   /* C99 6.7.4p3: An inline definition of a function with external
2328      linkage ... shall not contain a reference to an identifier with
2329      internal linkage.  */
2330   else if (current_function_decl != 0
2331            && DECL_DECLARED_INLINE_P (current_function_decl)
2332            && DECL_EXTERNAL (current_function_decl)
2333            && VAR_OR_FUNCTION_DECL_P (ref)
2334            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2335            && ! TREE_PUBLIC (ref)
2336            && DECL_CONTEXT (ref) != current_function_decl)
2337     record_inline_static (loc, current_function_decl, ref,
2338                           csi_internal);
2339
2340   return ref;
2341 }
2342
2343 /* Record details of decls possibly used inside sizeof or typeof.  */
2344 struct maybe_used_decl
2345 {
2346   /* The decl.  */
2347   tree decl;
2348   /* The level seen at (in_sizeof + in_typeof).  */
2349   int level;
2350   /* The next one at this level or above, or NULL.  */
2351   struct maybe_used_decl *next;
2352 };
2353
2354 static struct maybe_used_decl *maybe_used_decls;
2355
2356 /* Record that DECL, an undefined static function reference seen
2357    inside sizeof or typeof, might be used if the operand of sizeof is
2358    a VLA type or the operand of typeof is a variably modified
2359    type.  */
2360
2361 static void
2362 record_maybe_used_decl (tree decl)
2363 {
2364   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2365   t->decl = decl;
2366   t->level = in_sizeof + in_typeof;
2367   t->next = maybe_used_decls;
2368   maybe_used_decls = t;
2369 }
2370
2371 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2372    USED is false, just discard them.  If it is true, mark them used
2373    (if no longer inside sizeof or typeof) or move them to the next
2374    level up (if still inside sizeof or typeof).  */
2375
2376 void
2377 pop_maybe_used (bool used)
2378 {
2379   struct maybe_used_decl *p = maybe_used_decls;
2380   int cur_level = in_sizeof + in_typeof;
2381   while (p && p->level > cur_level)
2382     {
2383       if (used)
2384         {
2385           if (cur_level == 0)
2386             C_DECL_USED (p->decl) = 1;
2387           else
2388             p->level = cur_level;
2389         }
2390       p = p->next;
2391     }
2392   if (!used || cur_level == 0)
2393     maybe_used_decls = p;
2394 }
2395
2396 /* Return the result of sizeof applied to EXPR.  */
2397
2398 struct c_expr
2399 c_expr_sizeof_expr (location_t loc, struct c_expr expr)
2400 {
2401   struct c_expr ret;
2402   if (expr.value == error_mark_node)
2403     {
2404       ret.value = error_mark_node;
2405       ret.original_code = ERROR_MARK;
2406       ret.original_type = NULL;
2407       pop_maybe_used (false);
2408     }
2409   else
2410     {
2411       bool expr_const_operands = true;
2412       tree folded_expr = c_fully_fold (expr.value, require_constant_value,
2413                                        &expr_const_operands);
2414       ret.value = c_sizeof (loc, TREE_TYPE (folded_expr));
2415       ret.original_code = ERROR_MARK;
2416       ret.original_type = NULL;
2417       if (c_vla_type_p (TREE_TYPE (folded_expr)))
2418         {
2419           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2420           ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2421                               folded_expr, ret.value);
2422           C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !expr_const_operands;
2423           SET_EXPR_LOCATION (ret.value, loc);
2424         }
2425       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (folded_expr)));
2426     }
2427   return ret;
2428 }
2429
2430 /* Return the result of sizeof applied to T, a structure for the type
2431    name passed to sizeof (rather than the type itself).  LOC is the
2432    location of the original expression.  */
2433
2434 struct c_expr
2435 c_expr_sizeof_type (location_t loc, struct c_type_name *t)
2436 {
2437   tree type;
2438   struct c_expr ret;
2439   tree type_expr = NULL_TREE;
2440   bool type_expr_const = true;
2441   type = groktypename (t, &type_expr, &type_expr_const);
2442   ret.value = c_sizeof (loc, type);
2443   ret.original_code = ERROR_MARK;
2444   ret.original_type = NULL;
2445   if ((type_expr || TREE_CODE (ret.value) == INTEGER_CST)
2446       && c_vla_type_p (type))
2447     {
2448       /* If the type is a [*] array, it is a VLA but is represented as
2449          having a size of zero.  In such a case we must ensure that
2450          the result of sizeof does not get folded to a constant by
2451          c_fully_fold, because if the size is evaluated the result is
2452          not constant and so constraints on zero or negative size
2453          arrays must not be applied when this sizeof call is inside
2454          another array declarator.  */
2455       if (!type_expr)
2456         type_expr = integer_zero_node;
2457       ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2458                           type_expr, ret.value);
2459       C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !type_expr_const;
2460     }
2461   pop_maybe_used (type != error_mark_node
2462                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2463   return ret;
2464 }
2465
2466 /* Build a function call to function FUNCTION with parameters PARAMS.
2467    The function call is at LOC.
2468    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2469    TREE_VALUE of each node is a parameter-expression.
2470    FUNCTION's data type may be a function type or a pointer-to-function.  */
2471
2472 tree
2473 build_function_call (location_t loc, tree function, tree params)
2474 {
2475   VEC(tree,gc) *vec;
2476   tree ret;
2477
2478   vec = VEC_alloc (tree, gc, list_length (params));
2479   for (; params; params = TREE_CHAIN (params))
2480     VEC_quick_push (tree, vec, TREE_VALUE (params));
2481   ret = build_function_call_vec (loc, function, vec, NULL);
2482   VEC_free (tree, gc, vec);
2483   return ret;
2484 }
2485
2486 /* Build a function call to function FUNCTION with parameters PARAMS.
2487    ORIGTYPES, if not NULL, is a vector of types; each element is
2488    either NULL or the original type of the corresponding element in
2489    PARAMS.  The original type may differ from TREE_TYPE of the
2490    parameter for enums.  FUNCTION's data type may be a function type
2491    or pointer-to-function.  This function changes the elements of
2492    PARAMS.  */
2493
2494 tree
2495 build_function_call_vec (location_t loc, tree function, VEC(tree,gc) *params,
2496                          VEC(tree,gc) *origtypes)
2497 {
2498   tree fntype, fundecl = 0;
2499   tree name = NULL_TREE, result;
2500   tree tem;
2501   int nargs;
2502   tree *argarray;
2503
2504
2505   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2506   STRIP_TYPE_NOPS (function);
2507
2508   /* Convert anything with function type to a pointer-to-function.  */
2509   if (TREE_CODE (function) == FUNCTION_DECL)
2510     {
2511       /* Implement type-directed function overloading for builtins.
2512          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2513          handle all the type checking.  The result is a complete expression
2514          that implements this function call.  */
2515       tem = resolve_overloaded_builtin (loc, function, params);
2516       if (tem)
2517         return tem;
2518
2519       name = DECL_NAME (function);
2520       fundecl = function;
2521     }
2522   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2523     function = function_to_pointer_conversion (loc, function);
2524
2525   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2526      expressions, like those used for ObjC messenger dispatches.  */
2527   if (!VEC_empty (tree, params))
2528     function = objc_rewrite_function_call (function,
2529                                            VEC_index (tree, params, 0));
2530
2531   function = c_fully_fold (function, false, NULL);
2532
2533   fntype = TREE_TYPE (function);
2534
2535   if (TREE_CODE (fntype) == ERROR_MARK)
2536     return error_mark_node;
2537
2538   if (!(TREE_CODE (fntype) == POINTER_TYPE
2539         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2540     {
2541       error_at (loc, "called object %qE is not a function", function);
2542       return error_mark_node;
2543     }
2544
2545   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2546     current_function_returns_abnormally = 1;
2547
2548   /* fntype now gets the type of function pointed to.  */
2549   fntype = TREE_TYPE (fntype);
2550
2551   /* Convert the parameters to the types declared in the
2552      function prototype, or apply default promotions.  */
2553
2554   nargs = convert_arguments (TYPE_ARG_TYPES (fntype), params, origtypes,
2555                              function, fundecl);
2556   if (nargs < 0)
2557     return error_mark_node;
2558
2559   /* Check that the function is called through a compatible prototype.
2560      If it is not, replace the call by a trap, wrapped up in a compound
2561      expression if necessary.  This has the nice side-effect to prevent
2562      the tree-inliner from generating invalid assignment trees which may
2563      blow up in the RTL expander later.  */
2564   if (CONVERT_EXPR_P (function)
2565       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2566       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2567       && !comptypes (fntype, TREE_TYPE (tem)))
2568     {
2569       tree return_type = TREE_TYPE (fntype);
2570       tree trap = build_function_call (loc, built_in_decls[BUILT_IN_TRAP],
2571                                        NULL_TREE);
2572       int i;
2573
2574       /* This situation leads to run-time undefined behavior.  We can't,
2575          therefore, simply error unless we can prove that all possible
2576          executions of the program must execute the code.  */
2577       if (warning_at (loc, 0, "function called through a non-compatible type"))
2578         /* We can, however, treat "undefined" any way we please.
2579            Call abort to encourage the user to fix the program.  */
2580         inform (loc, "if this code is reached, the program will abort");
2581       /* Before the abort, allow the function arguments to exit or
2582          call longjmp.  */
2583       for (i = 0; i < nargs; i++)
2584         trap = build2 (COMPOUND_EXPR, void_type_node,
2585                        VEC_index (tree, params, i), trap);
2586
2587       if (VOID_TYPE_P (return_type))
2588         {
2589           if (TYPE_QUALS (return_type) != TYPE_UNQUALIFIED)
2590             pedwarn (loc, 0,
2591                      "function with qualified void return type called");
2592           return trap;
2593         }
2594       else
2595         {
2596           tree rhs;
2597
2598           if (AGGREGATE_TYPE_P (return_type))
2599             rhs = build_compound_literal (loc, return_type,
2600                                           build_constructor (return_type, 0),
2601                                           false);
2602           else
2603             rhs = fold_convert_loc (loc, return_type, integer_zero_node);
2604
2605           return require_complete_type (build2 (COMPOUND_EXPR, return_type,
2606                                                 trap, rhs));
2607         }
2608     }
2609
2610   argarray = VEC_address (tree, params);
2611
2612   /* Check that arguments to builtin functions match the expectations.  */
2613   if (fundecl
2614       && DECL_BUILT_IN (fundecl)
2615       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2616       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2617     return error_mark_node;
2618
2619   /* Check that the arguments to the function are valid.  */
2620   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2621                             TYPE_ARG_TYPES (fntype));
2622
2623   if (name != NULL_TREE
2624       && !strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10))
2625     {
2626       if (require_constant_value)
2627         result =
2628           fold_build_call_array_initializer_loc (loc, TREE_TYPE (fntype),
2629                                                  function, nargs, argarray);
2630       else
2631         result = fold_build_call_array_loc (loc, TREE_TYPE (fntype),
2632                                             function, nargs, argarray);
2633       if (TREE_CODE (result) == NOP_EXPR
2634           && TREE_CODE (TREE_OPERAND (result, 0)) == INTEGER_CST)
2635         STRIP_TYPE_NOPS (result);
2636     }
2637   else
2638     result = build_call_array_loc (loc, TREE_TYPE (fntype),
2639                                    function, nargs, argarray);
2640
2641   if (VOID_TYPE_P (TREE_TYPE (result)))
2642     {
2643       if (TYPE_QUALS (TREE_TYPE (result)) != TYPE_UNQUALIFIED)
2644         pedwarn (loc, 0,
2645                  "function with qualified void return type called");
2646       return result;
2647     }
2648   return require_complete_type (result);
2649 }
2650 \f
2651 /* Convert the argument expressions in the vector VALUES
2652    to the types in the list TYPELIST.
2653
2654    If TYPELIST is exhausted, or when an element has NULL as its type,
2655    perform the default conversions.
2656
2657    ORIGTYPES is the original types of the expressions in VALUES.  This
2658    holds the type of enum values which have been converted to integral
2659    types.  It may be NULL.
2660
2661    FUNCTION is a tree for the called function.  It is used only for
2662    error messages, where it is formatted with %qE.
2663
2664    This is also where warnings about wrong number of args are generated.
2665
2666    Returns the actual number of arguments processed (which may be less
2667    than the length of VALUES in some error situations), or -1 on
2668    failure.  */
2669
2670 static int
2671 convert_arguments (tree typelist, VEC(tree,gc) *values,
2672                    VEC(tree,gc) *origtypes, tree function, tree fundecl)
2673 {
2674   tree typetail, val;
2675   unsigned int parmnum;
2676   const bool type_generic = fundecl
2677     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2678   bool type_generic_remove_excess_precision = false;
2679   tree selector;
2680
2681   /* Change pointer to function to the function itself for
2682      diagnostics.  */
2683   if (TREE_CODE (function) == ADDR_EXPR
2684       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2685     function = TREE_OPERAND (function, 0);
2686
2687   /* Handle an ObjC selector specially for diagnostics.  */
2688   selector = objc_message_selector ();
2689
2690   /* For type-generic built-in functions, determine whether excess
2691      precision should be removed (classification) or not
2692      (comparison).  */
2693   if (type_generic
2694       && DECL_BUILT_IN (fundecl)
2695       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL)
2696     {
2697       switch (DECL_FUNCTION_CODE (fundecl))
2698         {
2699         case BUILT_IN_ISFINITE:
2700         case BUILT_IN_ISINF:
2701         case BUILT_IN_ISINF_SIGN:
2702         case BUILT_IN_ISNAN:
2703         case BUILT_IN_ISNORMAL:
2704         case BUILT_IN_FPCLASSIFY:
2705           type_generic_remove_excess_precision = true;
2706           break;
2707
2708         default:
2709           type_generic_remove_excess_precision = false;
2710           break;
2711         }
2712     }
2713
2714   /* Scan the given expressions and types, producing individual
2715      converted arguments.  */
2716
2717   for (typetail = typelist, parmnum = 0;
2718        VEC_iterate (tree, values, parmnum, val);
2719        ++parmnum)
2720     {
2721       tree type = typetail ? TREE_VALUE (typetail) : 0;
2722       tree valtype = TREE_TYPE (val);
2723       tree rname = function;
2724       int argnum = parmnum + 1;
2725       const char *invalid_func_diag;
2726       bool excess_precision = false;
2727       bool npc;
2728       tree parmval;
2729
2730       if (type == void_type_node)
2731         {
2732           error ("too many arguments to function %qE", function);
2733           return parmnum;
2734         }
2735
2736       if (selector && argnum > 2)
2737         {
2738           rname = selector;
2739           argnum -= 2;
2740         }
2741
2742       npc = null_pointer_constant_p (val);
2743
2744       /* If there is excess precision and a prototype, convert once to
2745          the required type rather than converting via the semantic
2746          type.  Likewise without a prototype a float value represented
2747          as long double should be converted once to double.  But for
2748          type-generic classification functions excess precision must
2749          be removed here.  */
2750       if (TREE_CODE (val) == EXCESS_PRECISION_EXPR
2751           && (type || !type_generic || !type_generic_remove_excess_precision))
2752         {
2753           val = TREE_OPERAND (val, 0);
2754           excess_precision = true;
2755         }
2756       val = c_fully_fold (val, false, NULL);
2757       STRIP_TYPE_NOPS (val);
2758
2759       val = require_complete_type (val);
2760
2761       if (type != 0)
2762         {
2763           /* Formal parm type is specified by a function prototype.  */
2764
2765           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2766             {
2767               error ("type of formal parameter %d is incomplete", parmnum + 1);
2768               parmval = val;
2769             }
2770           else
2771             {
2772               tree origtype;
2773
2774               /* Optionally warn about conversions that
2775                  differ from the default conversions.  */
2776               if (warn_traditional_conversion || warn_traditional)
2777                 {
2778                   unsigned int formal_prec = TYPE_PRECISION (type);
2779
2780                   if (INTEGRAL_TYPE_P (type)
2781                       && TREE_CODE (valtype) == REAL_TYPE)
2782                     warning (0, "passing argument %d of %qE as integer "
2783                              "rather than floating due to prototype",
2784                              argnum, rname);
2785                   if (INTEGRAL_TYPE_P (type)
2786                       && TREE_CODE (valtype) == COMPLEX_TYPE)
2787                     warning (0, "passing argument %d of %qE as integer "
2788                              "rather than complex due to prototype",
2789                              argnum, rname);
2790                   else if (TREE_CODE (type) == COMPLEX_TYPE
2791                            && TREE_CODE (valtype) == REAL_TYPE)
2792                     warning (0, "passing argument %d of %qE as complex "
2793                              "rather than floating due to prototype",
2794                              argnum, rname);
2795                   else if (TREE_CODE (type) == REAL_TYPE
2796                            && INTEGRAL_TYPE_P (valtype))
2797                     warning (0, "passing argument %d of %qE as floating "
2798                              "rather than integer due to prototype",
2799                              argnum, rname);
2800                   else if (TREE_CODE (type) == COMPLEX_TYPE
2801                            && INTEGRAL_TYPE_P (valtype))
2802                     warning (0, "passing argument %d of %qE as complex "
2803                              "rather than integer due to prototype",
2804                              argnum, rname);
2805                   else if (TREE_CODE (type) == REAL_TYPE
2806                            && TREE_CODE (valtype) == COMPLEX_TYPE)
2807                     warning (0, "passing argument %d of %qE as floating "
2808                              "rather than complex due to prototype",
2809                              argnum, rname);
2810                   /* ??? At some point, messages should be written about
2811                      conversions between complex types, but that's too messy
2812                      to do now.  */
2813                   else if (TREE_CODE (type) == REAL_TYPE
2814                            && TREE_CODE (valtype) == REAL_TYPE)
2815                     {
2816                       /* Warn if any argument is passed as `float',
2817                          since without a prototype it would be `double'.  */
2818                       if (formal_prec == TYPE_PRECISION (float_type_node)
2819                           && type != dfloat32_type_node)
2820                         warning (0, "passing argument %d of %qE as %<float%> "
2821                                  "rather than %<double%> due to prototype",
2822                                  argnum, rname);
2823
2824                       /* Warn if mismatch between argument and prototype
2825                          for decimal float types.  Warn of conversions with
2826                          binary float types and of precision narrowing due to
2827                          prototype. */
2828                       else if (type != valtype
2829                                && (type == dfloat32_type_node
2830                                    || type == dfloat64_type_node
2831                                    || type == dfloat128_type_node
2832                                    || valtype == dfloat32_type_node
2833                                    || valtype == dfloat64_type_node
2834                                    || valtype == dfloat128_type_node)
2835                                && (formal_prec
2836                                    <= TYPE_PRECISION (valtype)
2837                                    || (type == dfloat128_type_node
2838                                        && (valtype
2839                                            != dfloat64_type_node
2840                                            && (valtype
2841                                                != dfloat32_type_node)))
2842                                    || (type == dfloat64_type_node
2843                                        && (valtype
2844                                            != dfloat32_type_node))))
2845                         warning (0, "passing argument %d of %qE as %qT "
2846                                  "rather than %qT due to prototype",
2847                                  argnum, rname, type, valtype);
2848
2849                     }
2850                   /* Detect integer changing in width or signedness.
2851                      These warnings are only activated with
2852                      -Wtraditional-conversion, not with -Wtraditional.  */
2853                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2854                            && INTEGRAL_TYPE_P (valtype))
2855                     {
2856                       tree would_have_been = default_conversion (val);
2857                       tree type1 = TREE_TYPE (would_have_been);
2858
2859                       if (TREE_CODE (type) == ENUMERAL_TYPE
2860                           && (TYPE_MAIN_VARIANT (type)
2861                               == TYPE_MAIN_VARIANT (valtype)))
2862                         /* No warning if function asks for enum
2863                            and the actual arg is that enum type.  */
2864                         ;
2865                       else if (formal_prec != TYPE_PRECISION (type1))
2866                         warning (OPT_Wtraditional_conversion,
2867                                  "passing argument %d of %qE "
2868                                  "with different width due to prototype",
2869                                  argnum, rname);
2870                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2871                         ;
2872                       /* Don't complain if the formal parameter type
2873                          is an enum, because we can't tell now whether
2874                          the value was an enum--even the same enum.  */
2875                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2876                         ;
2877                       else if (TREE_CODE (val) == INTEGER_CST
2878                                && int_fits_type_p (val, type))
2879                         /* Change in signedness doesn't matter
2880                            if a constant value is unaffected.  */
2881                         ;
2882                       /* If the value is extended from a narrower
2883                          unsigned type, it doesn't matter whether we
2884                          pass it as signed or unsigned; the value
2885                          certainly is the same either way.  */
2886                       else if (TYPE_PRECISION (valtype) < TYPE_PRECISION (type)
2887                                && TYPE_UNSIGNED (valtype))
2888                         ;
2889                       else if (TYPE_UNSIGNED (type))
2890                         warning (OPT_Wtraditional_conversion,
2891                                  "passing argument %d of %qE "
2892                                  "as unsigned due to prototype",
2893                                  argnum, rname);
2894                       else
2895                         warning (OPT_Wtraditional_conversion,
2896                                  "passing argument %d of %qE "
2897                                  "as signed due to prototype", argnum, rname);
2898                     }
2899                 }
2900
2901               /* Possibly restore an EXCESS_PRECISION_EXPR for the
2902                  sake of better warnings from convert_and_check.  */
2903               if (excess_precision)
2904                 val = build1 (EXCESS_PRECISION_EXPR, valtype, val);
2905               origtype = (origtypes == NULL
2906                           ? NULL_TREE
2907                           : VEC_index (tree, origtypes, parmnum));
2908               parmval = convert_for_assignment (input_location, type, val,
2909                                                 origtype, ic_argpass, npc,
2910                                                 fundecl, function,
2911                                                 parmnum + 1);
2912
2913               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2914                   && INTEGRAL_TYPE_P (type)
2915                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2916                 parmval = default_conversion (parmval);
2917             }
2918         }
2919       else if (TREE_CODE (valtype) == REAL_TYPE
2920                && (TYPE_PRECISION (valtype)
2921                    < TYPE_PRECISION (double_type_node))
2922                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (valtype)))
2923         {
2924           if (type_generic)
2925             parmval = val;
2926           else
2927             /* Convert `float' to `double'.  */
2928             parmval = convert (double_type_node, val);
2929         }
2930       else if (excess_precision && !type_generic)
2931         /* A "double" argument with excess precision being passed
2932            without a prototype or in variable arguments.  */
2933         parmval = convert (valtype, val);
2934       else if ((invalid_func_diag =
2935                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2936         {
2937           error (invalid_func_diag);
2938           return -1;
2939         }
2940       else
2941         /* Convert `short' and `char' to full-size `int'.  */
2942         parmval = default_conversion (val);
2943
2944       VEC_replace (tree, values, parmnum, parmval);
2945
2946       if (typetail)
2947         typetail = TREE_CHAIN (typetail);
2948     }
2949
2950   gcc_assert (parmnum == VEC_length (tree, values));
2951
2952   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2953     {
2954       error ("too few arguments to function %qE", function);
2955       return -1;
2956     }
2957
2958   return parmnum;
2959 }
2960 \f
2961 /* This is the entry point used by the parser to build unary operators
2962    in the input.  CODE, a tree_code, specifies the unary operator, and
2963    ARG is the operand.  For unary plus, the C parser currently uses
2964    CONVERT_EXPR for code.
2965
2966    LOC is the location to use for the tree generated.
2967 */
2968
2969 struct c_expr
2970 parser_build_unary_op (location_t loc, enum tree_code code, struct c_expr arg)
2971 {
2972   struct c_expr result;
2973
2974   result.value = build_unary_op (loc, code, arg.value, 0);
2975   result.original_code = code;
2976   result.original_type = NULL;
2977
2978   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2979     overflow_warning (loc, result.value);
2980
2981   return result;
2982 }
2983
2984 /* This is the entry point used by the parser to build binary operators
2985    in the input.  CODE, a tree_code, specifies the binary operator, and
2986    ARG1 and ARG2 are the operands.  In addition to constructing the
2987    expression, we check for operands that were written with other binary
2988    operators in a way that is likely to confuse the user.
2989
2990    LOCATION is the location of the binary operator.  */
2991
2992 struct c_expr
2993 parser_build_binary_op (location_t location, enum tree_code code,
2994                         struct c_expr arg1, struct c_expr arg2)
2995 {
2996   struct c_expr result;
2997
2998   enum tree_code code1 = arg1.original_code;
2999   enum tree_code code2 = arg2.original_code;
3000   tree type1 = (arg1.original_type
3001                 ? arg1.original_type
3002                 : TREE_TYPE (arg1.value));
3003   tree type2 = (arg2.original_type
3004                 ? arg2.original_type
3005                 : TREE_TYPE (arg2.value));
3006
3007   result.value = build_binary_op (location, code,
3008                                   arg1.value, arg2.value, 1);
3009   result.original_code = code;
3010   result.original_type = NULL;
3011
3012   if (TREE_CODE (result.value) == ERROR_MARK)
3013     return result;
3014
3015   if (location != UNKNOWN_LOCATION)
3016     protected_set_expr_location (result.value, location);
3017
3018   /* Check for cases such as x+y<<z which users are likely
3019      to misinterpret.  */
3020   if (warn_parentheses)
3021     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
3022
3023   if (warn_logical_op)
3024     warn_logical_operator (input_location, code, TREE_TYPE (result.value),
3025                            code1, arg1.value, code2, arg2.value);
3026
3027   /* Warn about comparisons against string literals, with the exception
3028      of testing for equality or inequality of a string literal with NULL.  */
3029   if (code == EQ_EXPR || code == NE_EXPR)
3030     {
3031       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
3032           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
3033         warning_at (location, OPT_Waddress,
3034                     "comparison with string literal results in unspecified behavior");
3035     }
3036   else if (TREE_CODE_CLASS (code) == tcc_comparison
3037            && (code1 == STRING_CST || code2 == STRING_CST))
3038     warning_at (location, OPT_Waddress,
3039                 "comparison with string literal results in unspecified behavior");
3040
3041   if (TREE_OVERFLOW_P (result.value)
3042       && !TREE_OVERFLOW_P (arg1.value)
3043       && !TREE_OVERFLOW_P (arg2.value))
3044     overflow_warning (location, result.value);
3045
3046   /* Warn about comparisons of different enum types.  */
3047   if (warn_enum_compare
3048       && TREE_CODE_CLASS (code) == tcc_comparison
3049       && TREE_CODE (type1) == ENUMERAL_TYPE
3050       && TREE_CODE (type2) == ENUMERAL_TYPE
3051       && TYPE_MAIN_VARIANT (type1) != TYPE_MAIN_VARIANT (type2))
3052     warning_at (location, OPT_Wenum_compare,
3053                 "comparison between %qT and %qT",
3054                 type1, type2);
3055
3056   return result;
3057 }
3058 \f
3059 /* Return a tree for the difference of pointers OP0 and OP1.
3060    The resulting tree has type int.  */
3061
3062 static tree
3063 pointer_diff (location_t loc, tree op0, tree op1)
3064 {
3065   tree restype = ptrdiff_type_node;
3066
3067   tree target_type = TREE_TYPE (TREE_TYPE (op0));
3068   tree con0, con1, lit0, lit1;
3069   tree orig_op1 = op1;
3070
3071   if (TREE_CODE (target_type) == VOID_TYPE)
3072     pedwarn (loc, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3073              "pointer of type %<void *%> used in subtraction");
3074   if (TREE_CODE (target_type) == FUNCTION_TYPE)
3075     pedwarn (loc, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3076              "pointer to a function used in subtraction");
3077
3078   /* If the conversion to ptrdiff_type does anything like widening or
3079      converting a partial to an integral mode, we get a convert_expression
3080      that is in the way to do any simplifications.
3081      (fold-const.c doesn't know that the extra bits won't be needed.
3082      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
3083      different mode in place.)
3084      So first try to find a common term here 'by hand'; we want to cover
3085      at least the cases that occur in legal static initializers.  */
3086   if (CONVERT_EXPR_P (op0)
3087       && (TYPE_PRECISION (TREE_TYPE (op0))
3088           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
3089     con0 = TREE_OPERAND (op0, 0);
3090   else
3091     con0 = op0;
3092   if (CONVERT_EXPR_P (op1)
3093       && (TYPE_PRECISION (TREE_TYPE (op1))
3094           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
3095     con1 = TREE_OPERAND (op1, 0);
3096   else
3097     con1 = op1;
3098
3099   if (TREE_CODE (con0) == PLUS_EXPR)
3100     {
3101       lit0 = TREE_OPERAND (con0, 1);
3102       con0 = TREE_OPERAND (con0, 0);
3103     }
3104   else
3105     lit0 = integer_zero_node;
3106
3107   if (TREE_CODE (con1) == PLUS_EXPR)
3108     {
3109       lit1 = TREE_OPERAND (con1, 1);
3110       con1 = TREE_OPERAND (con1, 0);
3111     }
3112   else
3113     lit1 = integer_zero_node;
3114
3115   if (operand_equal_p (con0, con1, 0))
3116     {
3117       op0 = lit0;
3118       op1 = lit1;
3119     }
3120
3121
3122   /* First do the subtraction as integers;
3123      then drop through to build the divide operator.
3124      Do not do default conversions on the minus operator
3125      in case restype is a short type.  */
3126
3127   op0 = build_binary_op (loc,
3128                          MINUS_EXPR, convert (restype, op0),
3129                          convert (restype, op1), 0);
3130   /* This generates an error if op1 is pointer to incomplete type.  */
3131   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
3132     error_at (loc, "arithmetic on pointer to an incomplete type");
3133
3134   /* This generates an error if op0 is pointer to incomplete type.  */
3135   op1 = c_size_in_bytes (target_type);
3136
3137   /* Divide by the size, in easiest possible way.  */
3138   return fold_build2_loc (loc, EXACT_DIV_EXPR, restype,
3139                           op0, convert (restype, op1));
3140 }
3141 \f
3142 /* Construct and perhaps optimize a tree representation
3143    for a unary operation.  CODE, a tree_code, specifies the operation
3144    and XARG is the operand.
3145    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
3146    the default promotions (such as from short to int).
3147    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
3148    allows non-lvalues; this is only used to handle conversion of non-lvalue
3149    arrays to pointers in C99.
3150
3151    LOCATION is the location of the operator.  */
3152
3153 tree
3154 build_unary_op (location_t location,
3155                 enum tree_code code, tree xarg, int flag)
3156 {
3157   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3158   tree arg = xarg;
3159   tree argtype = 0;
3160   enum tree_code typecode;
3161   tree val;
3162   tree ret = error_mark_node;
3163   tree eptype = NULL_TREE;
3164   int noconvert = flag;
3165   const char *invalid_op_diag;
3166   bool int_operands;
3167
3168   int_operands = EXPR_INT_CONST_OPERANDS (xarg);
3169   if (int_operands)
3170     arg = remove_c_maybe_const_expr (arg);
3171
3172   if (code != ADDR_EXPR)
3173     arg = require_complete_type (arg);
3174
3175   typecode = TREE_CODE (TREE_TYPE (arg));
3176   if (typecode == ERROR_MARK)
3177     return error_mark_node;
3178   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
3179     typecode = INTEGER_TYPE;
3180
3181   if ((invalid_op_diag
3182        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
3183     {
3184       error_at (location, invalid_op_diag);
3185       return error_mark_node;
3186     }
3187
3188   if (TREE_CODE (arg) == EXCESS_PRECISION_EXPR)
3189     {
3190       eptype = TREE_TYPE (arg);
3191       arg = TREE_OPERAND (arg, 0);
3192     }
3193
3194   switch (code)
3195     {
3196     case CONVERT_EXPR:
3197       /* This is used for unary plus, because a CONVERT_EXPR
3198          is enough to prevent anybody from looking inside for
3199          associativity, but won't generate any code.  */
3200       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3201             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3202             || typecode == VECTOR_TYPE))
3203         {
3204           error_at (location, "wrong type argument to unary plus");
3205           return error_mark_node;
3206         }
3207       else if (!noconvert)
3208         arg = default_conversion (arg);
3209       arg = non_lvalue_loc (location, arg);
3210       break;
3211
3212     case NEGATE_EXPR:
3213       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3214             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3215             || typecode == VECTOR_TYPE))
3216         {
3217           error_at (location, "wrong type argument to unary minus");
3218           return error_mark_node;
3219         }
3220       else if (!noconvert)
3221         arg = default_conversion (arg);
3222       break;
3223
3224     case BIT_NOT_EXPR:
3225       /* ~ works on integer types and non float vectors. */
3226       if (typecode == INTEGER_TYPE
3227           || (typecode == VECTOR_TYPE
3228               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
3229         {
3230           if (!noconvert)
3231             arg = default_conversion (arg);
3232         }
3233       else if (typecode == COMPLEX_TYPE)
3234         {
3235           code = CONJ_EXPR;
3236           pedwarn (location, OPT_pedantic,
3237                    "ISO C does not support %<~%> for complex conjugation");
3238           if (!noconvert)
3239             arg = default_conversion (arg);
3240         }
3241       else
3242         {
3243           error_at (location, "wrong type argument to bit-complement");
3244           return error_mark_node;
3245         }
3246       break;
3247
3248     case ABS_EXPR:
3249       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
3250         {
3251           error_at (location, "wrong type argument to abs");
3252           return error_mark_node;
3253         }
3254       else if (!noconvert)
3255         arg = default_conversion (arg);
3256       break;
3257
3258     case CONJ_EXPR:
3259       /* Conjugating a real value is a no-op, but allow it anyway.  */
3260       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3261             || typecode == COMPLEX_TYPE))
3262         {
3263           error_at (location, "wrong type argument to conjugation");
3264           return error_mark_node;
3265         }
3266       else if (!noconvert)
3267         arg = default_conversion (arg);
3268       break;
3269
3270     case TRUTH_NOT_EXPR:
3271       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3272           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3273           && typecode != COMPLEX_TYPE)
3274         {
3275           error_at (location,
3276                     "wrong type argument to unary exclamation mark");
3277           return error_mark_node;
3278         }
3279       arg = c_objc_common_truthvalue_conversion (location, arg);
3280       ret = invert_truthvalue_loc (location, arg);
3281       /* If the TRUTH_NOT_EXPR has been folded, reset the location.  */
3282       if (EXPR_P (ret) && EXPR_HAS_LOCATION (ret))
3283         location = EXPR_LOCATION (ret);
3284       goto return_build_unary_op;
3285
3286     case REALPART_EXPR:
3287       if (TREE_CODE (arg) == COMPLEX_CST)
3288         ret = TREE_REALPART (arg);
3289       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3290         ret = fold_build1_loc (location,
3291                                REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3292       else
3293         ret = arg;
3294       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3295         eptype = TREE_TYPE (eptype);
3296       goto return_build_unary_op;
3297
3298     case IMAGPART_EXPR:
3299       if (TREE_CODE (arg) == COMPLEX_CST)
3300         ret = TREE_IMAGPART (arg);
3301       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3302         ret = fold_build1_loc (location,
3303                                IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3304       else
3305         ret = omit_one_operand_loc (location, TREE_TYPE (arg),
3306                                 integer_zero_node, arg);
3307       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3308         eptype = TREE_TYPE (eptype);
3309       goto return_build_unary_op;
3310
3311     case PREINCREMENT_EXPR:
3312     case POSTINCREMENT_EXPR:
3313     case PREDECREMENT_EXPR:
3314     case POSTDECREMENT_EXPR:
3315
3316       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3317         {
3318           tree inner = build_unary_op (location, code,
3319                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3320           if (inner == error_mark_node)
3321             return error_mark_node;
3322           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3323                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3324           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3325           C_MAYBE_CONST_EXPR_NON_CONST (ret) = 1;
3326           goto return_build_unary_op;
3327         }
3328
3329       /* Complain about anything that is not a true lvalue.  */
3330       if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3331                                   || code == POSTINCREMENT_EXPR)
3332                                  ? lv_increment
3333                                  : lv_decrement)))
3334         return error_mark_node;
3335
3336       if (warn_cxx_compat && TREE_CODE (TREE_TYPE (arg)) == ENUMERAL_TYPE)
3337         {
3338           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3339             warning_at (location, OPT_Wc___compat,
3340                         "increment of enumeration value is invalid in C++");
3341           else
3342             warning_at (location, OPT_Wc___compat,
3343                         "decrement of enumeration value is invalid in C++");
3344         }
3345
3346       /* Ensure the argument is fully folded inside any SAVE_EXPR.  */
3347       arg = c_fully_fold (arg, false, NULL);
3348
3349       /* Increment or decrement the real part of the value,
3350          and don't change the imaginary part.  */
3351       if (typecode == COMPLEX_TYPE)
3352         {
3353           tree real, imag;
3354
3355           pedwarn (location, OPT_pedantic,
3356                    "ISO C does not support %<++%> and %<--%> on complex types");
3357
3358           arg = stabilize_reference (arg);
3359           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3360           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3361           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3362           if (real == error_mark_node || imag == error_mark_node)
3363             return error_mark_node;
3364           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3365                         real, imag);
3366           goto return_build_unary_op;
3367         }
3368
3369       /* Report invalid types.  */
3370
3371       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3372           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3373         {
3374           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3375             error_at (location, "wrong type argument to increment");
3376           else
3377             error_at (location, "wrong type argument to decrement");
3378
3379           return error_mark_node;
3380         }
3381
3382       {
3383         tree inc;
3384
3385         argtype = TREE_TYPE (arg);
3386
3387         /* Compute the increment.  */
3388
3389         if (typecode == POINTER_TYPE)
3390           {
3391             /* If pointer target is an undefined struct,
3392                we just cannot know how to do the arithmetic.  */
3393             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3394               {
3395                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3396                   error_at (location,
3397                             "increment of pointer to unknown structure");
3398                 else
3399                   error_at (location,
3400                             "decrement of pointer to unknown structure");
3401               }
3402             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3403                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3404               {
3405                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3406                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3407                            "wrong type argument to increment");
3408                 else
3409                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3410                            "wrong type argument to decrement");
3411               }
3412
3413             inc = c_size_in_bytes (TREE_TYPE (argtype));
3414             inc = fold_convert_loc (location, sizetype, inc);
3415           }
3416         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3417           {
3418             /* For signed fract types, we invert ++ to -- or
3419                -- to ++, and change inc from 1 to -1, because
3420                it is not possible to represent 1 in signed fract constants.
3421                For unsigned fract types, the result always overflows and
3422                we get an undefined (original) or the maximum value.  */
3423             if (code == PREINCREMENT_EXPR)
3424               code = PREDECREMENT_EXPR;
3425             else if (code == PREDECREMENT_EXPR)
3426               code = PREINCREMENT_EXPR;
3427             else if (code == POSTINCREMENT_EXPR)
3428               code = POSTDECREMENT_EXPR;
3429             else /* code == POSTDECREMENT_EXPR  */
3430               code = POSTINCREMENT_EXPR;
3431
3432             inc = integer_minus_one_node;
3433             inc = convert (argtype, inc);
3434           }
3435         else
3436           {
3437             inc = integer_one_node;
3438             inc = convert (argtype, inc);
3439           }
3440
3441         /* Report a read-only lvalue.  */
3442         if (TYPE_READONLY (argtype))
3443           {
3444             readonly_error (arg,
3445                             ((code == PREINCREMENT_EXPR
3446                               || code == POSTINCREMENT_EXPR)
3447                              ? lv_increment : lv_decrement));
3448             return error_mark_node;
3449           }
3450         else if (TREE_READONLY (arg))
3451           readonly_warning (arg,
3452                             ((code == PREINCREMENT_EXPR
3453                               || code == POSTINCREMENT_EXPR)
3454                              ? lv_increment : lv_decrement));
3455
3456         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3457           val = boolean_increment (code, arg);
3458         else
3459           val = build2 (code, TREE_TYPE (arg), arg, inc);
3460         TREE_SIDE_EFFECTS (val) = 1;
3461         if (TREE_CODE (val) != code)
3462           TREE_NO_WARNING (val) = 1;
3463         ret = val;
3464         goto return_build_unary_op;
3465       }
3466
3467     case ADDR_EXPR:
3468       /* Note that this operation never does default_conversion.  */
3469
3470       /* The operand of unary '&' must be an lvalue (which excludes
3471          expressions of type void), or, in C99, the result of a [] or
3472          unary '*' operator.  */
3473       if (VOID_TYPE_P (TREE_TYPE (arg))
3474           && TYPE_QUALS (TREE_TYPE (arg)) == TYPE_UNQUALIFIED
3475           && (TREE_CODE (arg) != INDIRECT_REF
3476               || !flag_isoc99))
3477         pedwarn (location, 0, "taking address of expression of type %<void%>");
3478
3479       /* Let &* cancel out to simplify resulting code.  */
3480       if (TREE_CODE (arg) == INDIRECT_REF)
3481         {
3482           /* Don't let this be an lvalue.  */
3483           if (lvalue_p (TREE_OPERAND (arg, 0)))
3484             return non_lvalue_loc (location, TREE_OPERAND (arg, 0));
3485           ret = TREE_OPERAND (arg, 0);
3486           goto return_build_unary_op;
3487         }
3488
3489       /* For &x[y], return x+y */
3490       if (TREE_CODE (arg) == ARRAY_REF)
3491         {
3492           tree op0 = TREE_OPERAND (arg, 0);
3493           if (!c_mark_addressable (op0))
3494             return error_mark_node;
3495           return build_binary_op (location, PLUS_EXPR,
3496                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3497                                    ? array_to_pointer_conversion (location,
3498                                                                   op0)
3499                                    : op0),
3500                                   TREE_OPERAND (arg, 1), 1);
3501         }
3502
3503       /* Anything not already handled and not a true memory reference
3504          or a non-lvalue array is an error.  */
3505       else if (typecode != FUNCTION_TYPE && !flag
3506                && !lvalue_or_else (arg, lv_addressof))
3507         return error_mark_node;
3508
3509       /* Move address operations inside C_MAYBE_CONST_EXPR to simplify
3510          folding later.  */
3511       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3512         {
3513           tree inner = build_unary_op (location, code,
3514                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3515           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3516                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3517           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3518           C_MAYBE_CONST_EXPR_NON_CONST (ret)
3519             = C_MAYBE_CONST_EXPR_NON_CONST (arg);
3520           goto return_build_unary_op;
3521         }
3522
3523       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3524       argtype = TREE_TYPE (arg);
3525
3526       /* If the lvalue is const or volatile, merge that into the type
3527          to which the address will point.  Note that you can't get a
3528          restricted pointer by taking the address of something, so we
3529          only have to deal with `const' and `volatile' here.  */
3530       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3531           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3532           argtype = c_build_type_variant (argtype,
3533                                           TREE_READONLY (arg),
3534                                           TREE_THIS_VOLATILE (arg));
3535
3536       if (!c_mark_addressable (arg))
3537         return error_mark_node;
3538
3539       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3540                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3541
3542       argtype = build_pointer_type (argtype);
3543
3544       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3545          when we have proper support for integer constant expressions.  */
3546       val = get_base_address (arg);
3547       if (val && TREE_CODE (val) == INDIRECT_REF
3548           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3549         {
3550           tree op0 = fold_convert_loc (location, sizetype,
3551                                        fold_offsetof (arg, val)), op1;
3552
3553           op1 = fold_convert_loc (location, argtype, TREE_OPERAND (val, 0));
3554           ret = fold_build2_loc (location, POINTER_PLUS_EXPR, argtype, op1, op0);
3555           goto return_build_unary_op;
3556         }
3557
3558       val = build1 (ADDR_EXPR, argtype, arg);
3559
3560       ret = val;
3561       goto return_build_unary_op;
3562
3563     default:
3564       gcc_unreachable ();
3565     }
3566
3567   if (argtype == 0)
3568     argtype = TREE_TYPE (arg);
3569   if (TREE_CODE (arg) == INTEGER_CST)
3570     ret = (require_constant_value
3571            ? fold_build1_initializer_loc (location, code, argtype, arg)
3572            : fold_build1_loc (location, code, argtype, arg));
3573   else
3574     ret = build1 (code, argtype, arg);
3575  return_build_unary_op:
3576   gcc_assert (ret != error_mark_node);
3577   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret)
3578       && !(TREE_CODE (xarg) == INTEGER_CST && !TREE_OVERFLOW (xarg)))
3579     ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
3580   else if (TREE_CODE (ret) != INTEGER_CST && int_operands)
3581     ret = note_integer_operands (ret);
3582   if (eptype)
3583     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3584   protected_set_expr_location (ret, location);
3585   return ret;
3586 }
3587
3588 /* Return nonzero if REF is an lvalue valid for this language.
3589    Lvalues can be assigned, unless their type has TYPE_READONLY.
3590    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3591
3592 bool
3593 lvalue_p (const_tree ref)
3594 {
3595   const enum tree_code code = TREE_CODE (ref);
3596
3597   switch (code)
3598     {
3599     case REALPART_EXPR:
3600     case IMAGPART_EXPR:
3601     case COMPONENT_REF:
3602       return lvalue_p (TREE_OPERAND (ref, 0));
3603
3604     case C_MAYBE_CONST_EXPR:
3605       return lvalue_p (TREE_OPERAND (ref, 1));
3606
3607     case COMPOUND_LITERAL_EXPR:
3608     case STRING_CST:
3609       return 1;
3610
3611     case INDIRECT_REF:
3612     case ARRAY_REF:
3613     case VAR_DECL:
3614     case PARM_DECL:
3615     case RESULT_DECL:
3616     case ERROR_MARK:
3617       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3618               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3619
3620     case BIND_EXPR:
3621       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3622
3623     default:
3624       return 0;
3625     }
3626 }
3627 \f
3628 /* Give an error for storing in something that is 'const'.  */
3629
3630 static void
3631 readonly_error (tree arg, enum lvalue_use use)
3632 {
3633   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3634               || use == lv_asm);
3635   /* Using this macro rather than (for example) arrays of messages
3636      ensures that all the format strings are checked at compile
3637      time.  */
3638 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3639                                    : (use == lv_increment ? (I)         \
3640                                    : (use == lv_decrement ? (D) : (AS))))
3641   if (TREE_CODE (arg) == COMPONENT_REF)
3642     {
3643       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3644         readonly_error (TREE_OPERAND (arg, 0), use);
3645       else
3646         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3647                              G_("increment of read-only member %qD"),
3648                              G_("decrement of read-only member %qD"),
3649                              G_("read-only member %qD used as %<asm%> output")),
3650                TREE_OPERAND (arg, 1));
3651     }
3652   else if (TREE_CODE (arg) == VAR_DECL)
3653     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3654                          G_("increment of read-only variable %qD"),
3655                          G_("decrement of read-only variable %qD"),
3656                          G_("read-only variable %qD used as %<asm%> output")),
3657            arg);
3658   else
3659     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3660                          G_("increment of read-only location %qE"),
3661                          G_("decrement of read-only location %qE"),
3662                          G_("read-only location %qE used as %<asm%> output")),
3663            arg);
3664 }
3665
3666 /* Give a warning for storing in something that is read-only in GCC
3667    terms but not const in ISO C terms.  */
3668
3669 static void
3670 readonly_warning (tree arg, enum lvalue_use use)
3671 {
3672   switch (use)
3673     {
3674     case lv_assign:
3675       warning (0, "assignment of read-only location %qE", arg);
3676       break;
3677     case lv_increment:
3678       warning (0, "increment of read-only location %qE", arg);
3679       break;
3680     case lv_decrement:
3681       warning (0, "decrement of read-only location %qE", arg);
3682       break;
3683     default:
3684       gcc_unreachable ();
3685     }
3686   return;
3687 }
3688
3689
3690 /* Return nonzero if REF is an lvalue valid for this language;
3691    otherwise, print an error message and return zero.  USE says
3692    how the lvalue is being used and so selects the error message.  */
3693
3694 static int
3695 lvalue_or_else (const_tree ref, enum lvalue_use use)
3696 {
3697   int win = lvalue_p (ref);
3698
3699   if (!win)
3700     lvalue_error (use);
3701
3702   return win;
3703 }
3704 \f
3705 /* Mark EXP saying that we need to be able to take the
3706    address of it; it should not be allocated in a register.
3707    Returns true if successful.  */
3708
3709 bool
3710 c_mark_addressable (tree exp)
3711 {
3712   tree x = exp;
3713
3714   while (1)
3715     switch (TREE_CODE (x))
3716       {
3717       case COMPONENT_REF:
3718         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3719           {
3720             error
3721               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3722             return false;
3723           }
3724
3725         /* ... fall through ...  */
3726
3727       case ADDR_EXPR:
3728       case ARRAY_REF:
3729       case REALPART_EXPR:
3730       case IMAGPART_EXPR:
3731         x = TREE_OPERAND (x, 0);
3732         break;
3733
3734       case COMPOUND_LITERAL_EXPR:
3735       case CONSTRUCTOR:
3736         TREE_ADDRESSABLE (x) = 1;
3737         return true;
3738
3739       case VAR_DECL:
3740       case CONST_DECL:
3741       case PARM_DECL:
3742       case RESULT_DECL:
3743         if (C_DECL_REGISTER (x)
3744             && DECL_NONLOCAL (x))
3745           {
3746             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3747               {
3748                 error
3749                   ("global register variable %qD used in nested function", x);
3750                 return false;
3751               }
3752             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3753           }
3754         else if (C_DECL_REGISTER (x))
3755           {
3756             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3757               error ("address of global register variable %qD requested", x);
3758             else
3759               error ("address of register variable %qD requested", x);
3760             return false;
3761           }
3762
3763         /* drops in */
3764       case FUNCTION_DECL:
3765         TREE_ADDRESSABLE (x) = 1;
3766         /* drops out */
3767       default:
3768         return true;
3769     }
3770 }
3771 \f
3772 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  If
3773    IFEXP_BCP then the condition is a call to __builtin_constant_p, and
3774    if folded to an integer constant then the unselected half may
3775    contain arbitrary operations not normally permitted in constant
3776    expressions.  Set the location of the expression to LOC.  */
3777
3778 tree
3779 build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
3780                         tree op1, tree op1_original_type, tree op2,
3781                         tree op2_original_type)
3782 {
3783   tree type1;
3784   tree type2;
3785   enum tree_code code1;
3786   enum tree_code code2;
3787   tree result_type = NULL;
3788   tree ep_result_type = NULL;
3789   tree orig_op1 = op1, orig_op2 = op2;
3790   bool int_const, op1_int_operands, op2_int_operands, int_operands;
3791   bool ifexp_int_operands;
3792   tree ret;
3793   bool objc_ok;
3794
3795   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
3796   if (op1_int_operands)
3797     op1 = remove_c_maybe_const_expr (op1);
3798   op2_int_operands = EXPR_INT_CONST_OPERANDS (orig_op2);
3799   if (op2_int_operands)
3800     op2 = remove_c_maybe_const_expr (op2);
3801   ifexp_int_operands = EXPR_INT_CONST_OPERANDS (ifexp);
3802   if (ifexp_int_operands)
3803     ifexp = remove_c_maybe_const_expr (ifexp);
3804
3805   /* Promote both alternatives.  */
3806
3807   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3808     op1 = default_conversion (op1);
3809   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3810     op2 = default_conversion (op2);
3811
3812   if (TREE_CODE (ifexp) == ERROR_MARK
3813       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3814       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3815     return error_mark_node;
3816
3817   type1 = TREE_TYPE (op1);
3818   code1 = TREE_CODE (type1);
3819   type2 = TREE_TYPE (op2);
3820   code2 = TREE_CODE (type2);
3821
3822   /* C90 does not permit non-lvalue arrays in conditional expressions.
3823      In C99 they will be pointers by now.  */
3824   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3825     {
3826       error_at (colon_loc, "non-lvalue array in conditional expression");
3827       return error_mark_node;
3828     }
3829
3830   objc_ok = objc_compare_types (type1, type2, -3, NULL_TREE);
3831
3832   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
3833        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3834       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
3835           || code1 == COMPLEX_TYPE)
3836       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3837           || code2 == COMPLEX_TYPE))
3838     {
3839       ep_result_type = c_common_type (type1, type2);
3840       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
3841         {
3842           op1 = TREE_OPERAND (op1, 0);
3843           type1 = TREE_TYPE (op1);
3844           gcc_assert (TREE_CODE (type1) == code1);
3845         }
3846       if (TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3847         {
3848           op2 = TREE_OPERAND (op2, 0);
3849           type2 = TREE_TYPE (op2);
3850           gcc_assert (TREE_CODE (type2) == code2);
3851         }
3852     }
3853
3854   if (warn_cxx_compat)
3855     {
3856       tree t1 = op1_original_type ? op1_original_type : TREE_TYPE (orig_op1);
3857       tree t2 = op2_original_type ? op2_original_type : TREE_TYPE (orig_op2);
3858
3859       if (TREE_CODE (t1) == ENUMERAL_TYPE
3860           && TREE_CODE (t2) == ENUMERAL_TYPE
3861           && TYPE_MAIN_VARIANT (t1) != TYPE_MAIN_VARIANT (t2))
3862         warning_at (colon_loc, OPT_Wc___compat,
3863                     ("different enum types in conditional is "
3864                      "invalid in C++: %qT vs %qT"),
3865                     t1, t2);
3866     }
3867
3868   /* Quickly detect the usual case where op1 and op2 have the same type
3869      after promotion.  */
3870   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3871     {
3872       if (type1 == type2)
3873         result_type = type1;
3874       else
3875         result_type = TYPE_MAIN_VARIANT (type1);
3876     }
3877   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3878             || code1 == COMPLEX_TYPE)
3879            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3880                || code2 == COMPLEX_TYPE))
3881     {
3882       result_type = c_common_type (type1, type2);
3883
3884       /* If -Wsign-compare, warn here if type1 and type2 have
3885          different signedness.  We'll promote the signed to unsigned
3886          and later code won't know it used to be different.
3887          Do this check on the original types, so that explicit casts
3888          will be considered, but default promotions won't.  */
3889       if (c_inhibit_evaluation_warnings == 0)
3890         {
3891           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3892           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3893
3894           if (unsigned_op1 ^ unsigned_op2)
3895             {
3896               bool ovf;
3897
3898               /* Do not warn if the result type is signed, since the
3899                  signed type will only be chosen if it can represent
3900                  all the values of the unsigned type.  */
3901               if (!TYPE_UNSIGNED (result_type))
3902                 /* OK */;
3903               else
3904                 {
3905                   bool op1_maybe_const = true;
3906                   bool op2_maybe_const = true;
3907
3908                   /* Do not warn if the signed quantity is an
3909                      unsuffixed integer literal (or some static
3910                      constant expression involving such literals) and
3911                      it is non-negative.  This warning requires the
3912                      operands to be folded for best results, so do
3913                      that folding in this case even without
3914                      warn_sign_compare to avoid warning options
3915                      possibly affecting code generation.  */
3916                   c_inhibit_evaluation_warnings
3917                     += (ifexp == truthvalue_false_node);
3918                   op1 = c_fully_fold (op1, require_constant_value,
3919                                       &op1_maybe_const);
3920                   c_inhibit_evaluation_warnings
3921                     -= (ifexp == truthvalue_false_node);
3922
3923                   c_inhibit_evaluation_warnings
3924                     += (ifexp == truthvalue_true_node);
3925                   op2 = c_fully_fold (op2, require_constant_value,
3926                                       &op2_maybe_const);
3927                   c_inhibit_evaluation_warnings
3928                     -= (ifexp == truthvalue_true_node);
3929
3930                   if (warn_sign_compare)
3931                     {
3932                       if ((unsigned_op2
3933                            && tree_expr_nonnegative_warnv_p (op1, &ovf))
3934                           || (unsigned_op1
3935                               && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3936                         /* OK */;
3937                       else
3938                         warning_at (colon_loc, OPT_Wsign_compare,
3939                                     ("signed and unsigned type in "
3940                                      "conditional expression"));
3941                     }
3942                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
3943                     {
3944                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
3945                                     NULL, op1);
3946                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
3947                     }
3948                   if (!op2_maybe_const || TREE_CODE (op2) != INTEGER_CST)
3949                     {
3950                       op2 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op2),
3951                                     NULL, op2);
3952                       C_MAYBE_CONST_EXPR_NON_CONST (op2) = !op2_maybe_const;
3953                     }
3954                 }
3955             }
3956         }
3957     }
3958   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3959     {
3960       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3961         pedwarn (colon_loc, OPT_pedantic,
3962                  "ISO C forbids conditional expr with only one void side");
3963       result_type = void_type_node;
3964     }
3965   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3966     {
3967       if (comp_target_types (colon_loc, type1, type2))
3968         result_type = common_pointer_type (type1, type2);
3969       else if (null_pointer_constant_p (orig_op1))
3970         result_type = qualify_type (type2, type1);
3971       else if (null_pointer_constant_p (orig_op2))
3972         result_type = qualify_type (type1, type2);
3973       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3974         {
3975           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3976             pedwarn (colon_loc, OPT_pedantic,
3977                      "ISO C forbids conditional expr between "
3978                      "%<void *%> and function pointer");
3979           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3980                                                           TREE_TYPE (type2)));
3981         }
3982       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3983         {
3984           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3985             pedwarn (colon_loc, OPT_pedantic,
3986                      "ISO C forbids conditional expr between "
3987                      "%<void *%> and function pointer");
3988           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3989                                                           TREE_TYPE (type1)));
3990         }
3991       else
3992         {
3993           if (!objc_ok)
3994             pedwarn (colon_loc, 0,
3995                      "pointer type mismatch in conditional expression");
3996           result_type = build_pointer_type (void_type_node);
3997         }
3998     }
3999   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
4000     {
4001       if (!null_pointer_constant_p (orig_op2))
4002         pedwarn (colon_loc, 0,
4003                  "pointer/integer type mismatch in conditional expression");
4004       else
4005         {
4006           op2 = null_pointer_node;
4007         }
4008       result_type = type1;
4009     }
4010   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
4011     {
4012       if (!null_pointer_constant_p (orig_op1))
4013         pedwarn (colon_loc, 0,
4014                  "pointer/integer type mismatch in conditional expression");
4015       else
4016         {
4017           op1 = null_pointer_node;
4018         }
4019       result_type = type2;
4020     }
4021
4022   if (!result_type)
4023     {
4024       if (flag_cond_mismatch)
4025         result_type = void_type_node;
4026       else
4027         {
4028           error_at (colon_loc, "type mismatch in conditional expression");
4029           return error_mark_node;
4030         }
4031     }
4032
4033   /* Merge const and volatile flags of the incoming types.  */
4034   result_type
4035     = build_type_variant (result_type,
4036                           TREE_READONLY (op1) || TREE_READONLY (op2),
4037                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
4038
4039   if (result_type != TREE_TYPE (op1))
4040     op1 = convert_and_check (result_type, op1);
4041   if (result_type != TREE_TYPE (op2))
4042     op2 = convert_and_check (result_type, op2);
4043
4044   if (ifexp_bcp && ifexp == truthvalue_true_node)
4045     {
4046       op2_int_operands = true;
4047       op1 = c_fully_fold (op1, require_constant_value, NULL);
4048     }
4049   if (ifexp_bcp && ifexp == truthvalue_false_node)
4050     {
4051       op1_int_operands = true;
4052       op2 = c_fully_fold (op2, require_constant_value, NULL);
4053     }
4054   int_const = int_operands = (ifexp_int_operands
4055                               && op1_int_operands
4056                               && op2_int_operands);
4057   if (int_operands)
4058     {
4059       int_const = ((ifexp == truthvalue_true_node
4060                     && TREE_CODE (orig_op1) == INTEGER_CST
4061                     && !TREE_OVERFLOW (orig_op1))
4062                    || (ifexp == truthvalue_false_node
4063                        && TREE_CODE (orig_op2) == INTEGER_CST
4064                        && !TREE_OVERFLOW (orig_op2)));
4065     }
4066   if (int_const || (ifexp_bcp && TREE_CODE (ifexp) == INTEGER_CST))
4067     ret = fold_build3_loc (colon_loc, COND_EXPR, result_type, ifexp, op1, op2);
4068   else
4069     {
4070       ret = build3 (COND_EXPR, result_type, ifexp, op1, op2);
4071       if (int_operands)
4072         ret = note_integer_operands (ret);
4073     }
4074   if (ep_result_type)
4075     ret = build1 (EXCESS_PRECISION_EXPR, ep_result_type, ret);
4076
4077   protected_set_expr_location (ret, colon_loc);
4078   return ret;
4079 }
4080 \f
4081 /* Return a compound expression that performs two expressions and
4082    returns the value of the second of them.
4083
4084    LOC is the location of the COMPOUND_EXPR.  */
4085
4086 tree
4087 build_compound_expr (location_t loc, tree expr1, tree expr2)
4088 {
4089   bool expr1_int_operands, expr2_int_operands;
4090   tree eptype = NULL_TREE;
4091   tree ret;
4092
4093   expr1_int_operands = EXPR_INT_CONST_OPERANDS (expr1);
4094   if (expr1_int_operands)
4095     expr1 = remove_c_maybe_const_expr (expr1);
4096   expr2_int_operands = EXPR_INT_CONST_OPERANDS (expr2);
4097   if (expr2_int_operands)
4098     expr2 = remove_c_maybe_const_expr (expr2);
4099
4100   if (TREE_CODE (expr1) == EXCESS_PRECISION_EXPR)
4101     expr1 = TREE_OPERAND (expr1, 0);
4102   if (TREE_CODE (expr2) == EXCESS_PRECISION_EXPR)
4103     {
4104       eptype = TREE_TYPE (expr2);
4105       expr2 = TREE_OPERAND (expr2, 0);
4106     }
4107
4108   if (!TREE_SIDE_EFFECTS (expr1))
4109     {
4110       /* The left-hand operand of a comma expression is like an expression
4111          statement: with -Wunused, we should warn if it doesn't have
4112          any side-effects, unless it was explicitly cast to (void).  */
4113       if (warn_unused_value)
4114         {
4115           if (VOID_TYPE_P (TREE_TYPE (expr1))
4116               && CONVERT_EXPR_P (expr1))
4117             ; /* (void) a, b */
4118           else if (VOID_TYPE_P (TREE_TYPE (expr1))
4119                    && TREE_CODE (expr1) == COMPOUND_EXPR
4120                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
4121             ; /* (void) a, (void) b, c */
4122           else
4123             warning_at (loc, OPT_Wunused_value,
4124                         "left-hand operand of comma expression has no effect");
4125         }
4126     }
4127
4128   /* With -Wunused, we should also warn if the left-hand operand does have
4129      side-effects, but computes a value which is not used.  For example, in
4130      `foo() + bar(), baz()' the result of the `+' operator is not used,
4131      so we should issue a warning.  */
4132   else if (warn_unused_value)
4133     warn_if_unused_value (expr1, loc);
4134
4135   if (expr2 == error_mark_node)
4136     return error_mark_node;
4137
4138   ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
4139
4140   if (flag_isoc99
4141       && expr1_int_operands
4142       && expr2_int_operands)
4143     ret = note_integer_operands (ret);
4144
4145   if (eptype)
4146     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
4147
4148   protected_set_expr_location (ret, loc);
4149   return ret;
4150 }
4151
4152 /* Issue -Wcast-qual warnings when appropriate.  TYPE is the type to
4153    which we are casting.  OTYPE is the type of the expression being
4154    cast.  Both TYPE and OTYPE are pointer types.  -Wcast-qual appeared
4155    on the command line.  */
4156
4157 static void
4158 handle_warn_cast_qual (tree type, tree otype)
4159 {
4160   tree in_type = type;
4161   tree in_otype = otype;
4162   int added = 0;
4163   int discarded = 0;
4164   bool is_const;
4165
4166   /* Check that the qualifiers on IN_TYPE are a superset of the
4167      qualifiers of IN_OTYPE.  The outermost level of POINTER_TYPE
4168      nodes is uninteresting and we stop as soon as we hit a
4169      non-POINTER_TYPE node on either type.  */
4170   do
4171     {
4172       in_otype = TREE_TYPE (in_otype);
4173       in_type = TREE_TYPE (in_type);
4174
4175       /* GNU C allows cv-qualified function types.  'const' means the
4176          function is very pure, 'volatile' means it can't return.  We
4177          need to warn when such qualifiers are added, not when they're
4178          taken away.  */
4179       if (TREE_CODE (in_otype) == FUNCTION_TYPE
4180           && TREE_CODE (in_type) == FUNCTION_TYPE)
4181         added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
4182       else
4183         discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
4184     }
4185   while (TREE_CODE (in_type) == POINTER_TYPE
4186          && TREE_CODE (in_otype) == POINTER_TYPE);
4187
4188   if (added)
4189     warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
4190
4191   if (discarded)
4192     /* There are qualifiers present in IN_OTYPE that are not present
4193        in IN_TYPE.  */
4194     warning (OPT_Wcast_qual,
4195              "cast discards qualifiers from pointer target type");
4196
4197   if (added || discarded)
4198     return;
4199
4200   /* A cast from **T to const **T is unsafe, because it can cause a
4201      const value to be changed with no additional warning.  We only
4202      issue this warning if T is the same on both sides, and we only
4203      issue the warning if there are the same number of pointers on
4204      both sides, as otherwise the cast is clearly unsafe anyhow.  A
4205      cast is unsafe when a qualifier is added at one level and const
4206      is not present at all outer levels.
4207
4208      To issue this warning, we check at each level whether the cast
4209      adds new qualifiers not already seen.  We don't need to special
4210      case function types, as they won't have the same
4211      TYPE_MAIN_VARIANT.  */
4212
4213   if (TYPE_MAIN_VARIANT (in_type) != TYPE_MAIN_VARIANT (in_otype))
4214     return;
4215   if (TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE)
4216     return;
4217
4218   in_type = type;
4219   in_otype = otype;
4220   is_const = TYPE_READONLY (TREE_TYPE (in_type));
4221   do
4222     {
4223       in_type = TREE_TYPE (in_type);
4224       in_otype = TREE_TYPE (in_otype);
4225       if ((TYPE_QUALS (in_type) &~ TYPE_QUALS (in_otype)) != 0
4226           && !is_const)
4227         {
4228           warning (OPT_Wcast_qual,
4229                    ("new qualifiers in middle of multi-level non-const cast "
4230                     "are unsafe"));
4231           break;
4232         }
4233       if (is_const)
4234         is_const = TYPE_READONLY (in_type);
4235     }
4236   while (TREE_CODE (in_type) == POINTER_TYPE);
4237 }
4238
4239 /* Build an expression representing a cast to type TYPE of expression EXPR.
4240    LOC is the location of the cast-- typically the open paren of the cast.  */
4241
4242 tree
4243 build_c_cast (location_t loc, tree type, tree expr)
4244 {
4245   tree value;
4246
4247   if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
4248     expr = TREE_OPERAND (expr, 0);
4249
4250   value = expr;
4251
4252   if (type == error_mark_node || expr == error_mark_node)
4253     return error_mark_node;
4254
4255   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
4256      only in <protocol> qualifications.  But when constructing cast expressions,
4257      the protocols do matter and must be kept around.  */
4258   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
4259     return build1 (NOP_EXPR, type, expr);
4260
4261   type = TYPE_MAIN_VARIANT (type);
4262
4263   if (TREE_CODE (type) == ARRAY_TYPE)
4264     {
4265       error_at (loc, "cast specifies array type");
4266       return error_mark_node;
4267     }
4268
4269   if (TREE_CODE (type) == FUNCTION_TYPE)
4270     {
4271       error_at (loc, "cast specifies function type");
4272       return error_mark_node;
4273     }
4274
4275   if (!VOID_TYPE_P (type))
4276     {
4277       value = require_complete_type (value);
4278       if (value == error_mark_node)
4279         return error_mark_node;
4280     }
4281
4282   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
4283     {
4284       if (TREE_CODE (type) == RECORD_TYPE
4285           || TREE_CODE (type) == UNION_TYPE)
4286         pedwarn (loc, OPT_pedantic,
4287                  "ISO C forbids casting nonscalar to the same type");
4288     }
4289   else if (TREE_CODE (type) == UNION_TYPE)
4290     {
4291       tree field;
4292
4293       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4294         if (TREE_TYPE (field) != error_mark_node
4295             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
4296                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
4297           break;
4298
4299       if (field)
4300         {
4301           tree t;
4302
4303           pedwarn (loc, OPT_pedantic, "ISO C forbids casts to union type");
4304           t = digest_init (loc, type,
4305                            build_constructor_single (type, field, value),
4306                            NULL_TREE, false, true, 0);
4307           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4308           return t;
4309         }
4310       error_at (loc, "cast to union type from type not present in union");
4311       return error_mark_node;
4312     }
4313   else
4314     {
4315       tree otype, ovalue;
4316
4317       if (type == void_type_node)
4318         {
4319           tree t = build1 (CONVERT_EXPR, type, value);
4320           SET_EXPR_LOCATION (t, loc);
4321           return t;
4322         }
4323
4324       otype = TREE_TYPE (value);
4325
4326       /* Optionally warn about potentially worrisome casts.  */
4327       if (warn_cast_qual
4328           && TREE_CODE (type) == POINTER_TYPE
4329           && TREE_CODE (otype) == POINTER_TYPE)
4330         handle_warn_cast_qual (type, otype);
4331
4332       /* Warn about possible alignment problems.  */
4333       if (STRICT_ALIGNMENT
4334           && TREE_CODE (type) == POINTER_TYPE
4335           && TREE_CODE (otype) == POINTER_TYPE
4336           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4337           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4338           /* Don't warn about opaque types, where the actual alignment
4339              restriction is unknown.  */
4340           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4341                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4342                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4343           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4344         warning_at (loc, OPT_Wcast_align,
4345                     "cast increases required alignment of target type");
4346
4347       if (TREE_CODE (type) == INTEGER_TYPE
4348           && TREE_CODE (otype) == POINTER_TYPE
4349           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4350       /* Unlike conversion of integers to pointers, where the
4351          warning is disabled for converting constants because
4352          of cases such as SIG_*, warn about converting constant
4353          pointers to integers. In some cases it may cause unwanted
4354          sign extension, and a warning is appropriate.  */
4355         warning_at (loc, OPT_Wpointer_to_int_cast,
4356                     "cast from pointer to integer of different size");
4357
4358       if (TREE_CODE (value) == CALL_EXPR
4359           && TREE_CODE (type) != TREE_CODE (otype))
4360         warning_at (loc, OPT_Wbad_function_cast,
4361                     "cast from function call of type %qT "
4362                     "to non-matching type %qT", otype, type);
4363
4364       if (TREE_CODE (type) == POINTER_TYPE
4365           && TREE_CODE (otype) == INTEGER_TYPE
4366           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4367           /* Don't warn about converting any constant.  */
4368           && !TREE_CONSTANT (value))
4369         warning_at (loc,
4370                     OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4371                     "of different size");
4372
4373       if (warn_strict_aliasing <= 2)
4374         strict_aliasing_warning (otype, type, expr);
4375
4376       /* If pedantic, warn for conversions between function and object
4377          pointer types, except for converting a null pointer constant
4378          to function pointer type.  */
4379       if (pedantic
4380           && TREE_CODE (type) == POINTER_TYPE
4381           && TREE_CODE (otype) == POINTER_TYPE
4382           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4383           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4384         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4385                  "conversion of function pointer to object pointer type");
4386
4387       if (pedantic
4388           && TREE_CODE (type) == POINTER_TYPE
4389           && TREE_CODE (otype) == POINTER_TYPE
4390           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4391           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4392           && !null_pointer_constant_p (value))
4393         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4394                  "conversion of object pointer to function pointer type");
4395
4396       ovalue = value;
4397       value = convert (type, value);
4398
4399       /* Ignore any integer overflow caused by the cast.  */
4400       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4401         {
4402           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4403             {
4404               if (!TREE_OVERFLOW (value))
4405                 {
4406                   /* Avoid clobbering a shared constant.  */
4407                   value = copy_node (value);
4408                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4409                 }
4410             }
4411           else if (TREE_OVERFLOW (value))
4412             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4413             value = build_int_cst_wide (TREE_TYPE (value),
4414                                         TREE_INT_CST_LOW (value),
4415                                         TREE_INT_CST_HIGH (value));
4416         }
4417     }
4418
4419   /* Don't let a cast be an lvalue.  */
4420   if (value == expr)
4421     value = non_lvalue_loc (loc, value);
4422
4423   /* Don't allow the results of casting to floating-point or complex
4424      types be confused with actual constants, or casts involving
4425      integer and pointer types other than direct integer-to-integer
4426      and integer-to-pointer be confused with integer constant
4427      expressions and null pointer constants.  */
4428   if (TREE_CODE (value) == REAL_CST
4429       || TREE_CODE (value) == COMPLEX_CST
4430       || (TREE_CODE (value) == INTEGER_CST
4431           && !((TREE_CODE (expr) == INTEGER_CST
4432                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4433                || TREE_CODE (expr) == REAL_CST
4434                || TREE_CODE (expr) == COMPLEX_CST)))
4435       value = build1 (NOP_EXPR, type, value);
4436
4437   if (CAN_HAVE_LOCATION_P (value))
4438     SET_EXPR_LOCATION (value, loc);
4439   return value;
4440 }
4441
4442 /* Interpret a cast of expression EXPR to type TYPE.  LOC is the
4443    location of the open paren of the cast, or the position of the cast
4444    expr.  */
4445 tree
4446 c_cast_expr (location_t loc, struct c_type_name *type_name, tree expr)
4447 {
4448   tree type;
4449   tree type_expr = NULL_TREE;
4450   bool type_expr_const = true;
4451   tree ret;
4452   int saved_wsp = warn_strict_prototypes;
4453
4454   /* This avoids warnings about unprototyped casts on
4455      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4456   if (TREE_CODE (expr) == INTEGER_CST)
4457     warn_strict_prototypes = 0;
4458   type = groktypename (type_name, &type_expr, &type_expr_const);
4459   warn_strict_prototypes = saved_wsp;
4460
4461   ret = build_c_cast (loc, type, expr);
4462   if (type_expr)
4463     {
4464       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4465       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4466       SET_EXPR_LOCATION (ret, loc);
4467     }
4468
4469   if (CAN_HAVE_LOCATION_P (ret) && !EXPR_HAS_LOCATION (ret))
4470     SET_EXPR_LOCATION (ret, loc);
4471
4472   /* C++ does not permits types to be defined in a cast.  */
4473   if (warn_cxx_compat && type_name->specs->tag_defined_p)
4474     warning_at (loc, OPT_Wc___compat,
4475                 "defining a type in a cast is invalid in C++");
4476
4477   return ret;
4478 }
4479 \f
4480 /* Build an assignment expression of lvalue LHS from value RHS.
4481    If LHS_ORIGTYPE is not NULL, it is the original type of LHS, which
4482    may differ from TREE_TYPE (LHS) for an enum bitfield.
4483    MODIFYCODE is the code for a binary operator that we use
4484    to combine the old value of LHS with RHS to get the new value.
4485    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4486    If RHS_ORIGTYPE is not NULL_TREE, it is the original type of RHS,
4487    which may differ from TREE_TYPE (RHS) for an enum value.
4488
4489    LOCATION is the location of the MODIFYCODE operator.
4490    RHS_LOC is the location of the RHS.  */
4491
4492 tree
4493 build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
4494                    enum tree_code modifycode,
4495                    location_t rhs_loc, tree rhs, tree rhs_origtype)
4496 {
4497   tree result;
4498   tree newrhs;
4499   tree rhs_semantic_type = NULL_TREE;
4500   tree lhstype = TREE_TYPE (lhs);
4501   tree olhstype = lhstype;
4502   bool npc;
4503
4504   /* Types that aren't fully specified cannot be used in assignments.  */
4505   lhs = require_complete_type (lhs);
4506
4507   /* Avoid duplicate error messages from operands that had errors.  */
4508   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4509     return error_mark_node;
4510
4511   if (!lvalue_or_else (lhs, lv_assign))
4512     return error_mark_node;
4513
4514   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4515     {
4516       rhs_semantic_type = TREE_TYPE (rhs);
4517       rhs = TREE_OPERAND (rhs, 0);
4518     }
4519
4520   newrhs = rhs;
4521
4522   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4523     {
4524       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4525                                       lhs_origtype, modifycode, rhs_loc, rhs,
4526                                       rhs_origtype);
4527       if (inner == error_mark_node)
4528         return error_mark_node;
4529       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4530                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4531       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4532       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4533       protected_set_expr_location (result, location);
4534       return result;
4535     }
4536
4537   /* If a binary op has been requested, combine the old LHS value with the RHS
4538      producing the value we should actually store into the LHS.  */
4539
4540   if (modifycode != NOP_EXPR)
4541     {
4542       lhs = c_fully_fold (lhs, false, NULL);
4543       lhs = stabilize_reference (lhs);
4544       newrhs = build_binary_op (location,
4545                                 modifycode, lhs, rhs, 1);
4546
4547       /* The original type of the right hand side is no longer
4548          meaningful.  */
4549       rhs_origtype = NULL_TREE;
4550     }
4551
4552   /* Give an error for storing in something that is 'const'.  */
4553
4554   if (TYPE_READONLY (lhstype)
4555       || ((TREE_CODE (lhstype) == RECORD_TYPE
4556            || TREE_CODE (lhstype) == UNION_TYPE)
4557           && C_TYPE_FIELDS_READONLY (lhstype)))
4558     {
4559       readonly_error (lhs, lv_assign);
4560       return error_mark_node;
4561     }
4562   else if (TREE_READONLY (lhs))
4563     readonly_warning (lhs, lv_assign);
4564
4565   /* If storing into a structure or union member,
4566      it has probably been given type `int'.
4567      Compute the type that would go with
4568      the actual amount of storage the member occupies.  */
4569
4570   if (TREE_CODE (lhs) == COMPONENT_REF
4571       && (TREE_CODE (lhstype) == INTEGER_TYPE
4572           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4573           || TREE_CODE (lhstype) == REAL_TYPE
4574           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4575     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4576
4577   /* If storing in a field that is in actuality a short or narrower than one,
4578      we must store in the field in its actual type.  */
4579
4580   if (lhstype != TREE_TYPE (lhs))
4581     {
4582       lhs = copy_node (lhs);
4583       TREE_TYPE (lhs) = lhstype;
4584     }
4585
4586   /* Issue -Wc++-compat warnings about an assignment to an enum type
4587      when LHS does not have its original type.  This happens for,
4588      e.g., an enum bitfield in a struct.  */
4589   if (warn_cxx_compat
4590       && lhs_origtype != NULL_TREE
4591       && lhs_origtype != lhstype
4592       && TREE_CODE (lhs_origtype) == ENUMERAL_TYPE)
4593     {
4594       tree checktype = (rhs_origtype != NULL_TREE
4595                         ? rhs_origtype
4596                         : TREE_TYPE (rhs));
4597       if (checktype != error_mark_node
4598           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (lhs_origtype))
4599         warning_at (location, OPT_Wc___compat,
4600                     "enum conversion in assignment is invalid in C++");
4601     }
4602
4603   /* Convert new value to destination type.  Fold it first, then
4604      restore any excess precision information, for the sake of
4605      conversion warnings.  */
4606
4607   npc = null_pointer_constant_p (newrhs);
4608   newrhs = c_fully_fold (newrhs, false, NULL);
4609   if (rhs_semantic_type)
4610     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4611   newrhs = convert_for_assignment (location, lhstype, newrhs, rhs_origtype,
4612                                    ic_assign, npc, NULL_TREE, NULL_TREE, 0);
4613   if (TREE_CODE (newrhs) == ERROR_MARK)
4614     return error_mark_node;
4615
4616   /* Emit ObjC write barrier, if necessary.  */
4617   if (c_dialect_objc () && flag_objc_gc)
4618     {
4619       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4620       if (result)
4621         {
4622           protected_set_expr_location (result, location);
4623           return result;
4624         }
4625     }
4626
4627   /* Scan operands.  */
4628
4629   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4630   TREE_SIDE_EFFECTS (result) = 1;
4631   protected_set_expr_location (result, location);
4632
4633   /* If we got the LHS in a different type for storing in,
4634      convert the result back to the nominal type of LHS
4635      so that the value we return always has the same type
4636      as the LHS argument.  */
4637
4638   if (olhstype == TREE_TYPE (result))
4639     return result;
4640
4641   result = convert_for_assignment (location, olhstype, result, rhs_origtype,
4642                                    ic_assign, false, NULL_TREE, NULL_TREE, 0);
4643   protected_set_expr_location (result, location);
4644   return result;
4645 }
4646 \f
4647 /* Convert value RHS to type TYPE as preparation for an assignment to
4648    an lvalue of type TYPE.  If ORIGTYPE is not NULL_TREE, it is the
4649    original type of RHS; this differs from TREE_TYPE (RHS) for enum
4650    types.  NULL_POINTER_CONSTANT says whether RHS was a null pointer
4651    constant before any folding.
4652    The real work of conversion is done by `convert'.
4653    The purpose of this function is to generate error messages
4654    for assignments that are not allowed in C.
4655    ERRTYPE says whether it is argument passing, assignment,
4656    initialization or return.
4657
4658    LOCATION is the location of the RHS.
4659    FUNCTION is a tree for the function being called.
4660    PARMNUM is the number of the argument, for printing in error messages.  */
4661
4662 static tree
4663 convert_for_assignment (location_t location, tree type, tree rhs,
4664                         tree origtype, enum impl_conv errtype,
4665                         bool null_pointer_constant, tree fundecl,
4666                         tree function, int parmnum)
4667 {
4668   enum tree_code codel = TREE_CODE (type);
4669   tree orig_rhs = rhs;
4670   tree rhstype;
4671   enum tree_code coder;
4672   tree rname = NULL_TREE;
4673   bool objc_ok = false;
4674
4675   if (errtype == ic_argpass)
4676     {
4677       tree selector;
4678       /* Change pointer to function to the function itself for
4679          diagnostics.  */
4680       if (TREE_CODE (function) == ADDR_EXPR
4681           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
4682         function = TREE_OPERAND (function, 0);
4683
4684       /* Handle an ObjC selector specially for diagnostics.  */
4685       selector = objc_message_selector ();
4686       rname = function;
4687       if (selector && parmnum > 2)
4688         {
4689           rname = selector;
4690           parmnum -= 2;
4691         }
4692     }
4693
4694   /* This macro is used to emit diagnostics to ensure that all format
4695      strings are complete sentences, visible to gettext and checked at
4696      compile time.  */
4697 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4698   do {                                                                   \
4699     switch (errtype)                                                     \
4700       {                                                                  \
4701       case ic_argpass:                                                   \
4702         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4703           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4704                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4705                   "expected %qT but argument is of type %qT",            \
4706                   type, rhstype);                                        \
4707         break;                                                           \
4708       case ic_assign:                                                    \
4709         pedwarn (LOCATION, OPT, AS);                                     \
4710         break;                                                           \
4711       case ic_init:                                                      \
4712         pedwarn (LOCATION, OPT, IN);                                     \
4713         break;                                                           \
4714       case ic_return:                                                    \
4715         pedwarn (LOCATION, OPT, RE);                                     \
4716         break;                                                           \
4717       default:                                                           \
4718         gcc_unreachable ();                                              \
4719       }                                                                  \
4720   } while (0)
4721
4722   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4723     rhs = TREE_OPERAND (rhs, 0);
4724
4725   rhstype = TREE_TYPE (rhs);
4726   coder = TREE_CODE (rhstype);
4727
4728   if (coder == ERROR_MARK)
4729     return error_mark_node;
4730
4731   if (c_dialect_objc ())
4732     {
4733       int parmno;
4734
4735       switch (errtype)
4736         {
4737         case ic_return:
4738           parmno = 0;
4739           break;
4740
4741         case ic_assign:
4742           parmno = -1;
4743           break;
4744
4745         case ic_init:
4746           parmno = -2;
4747           break;
4748
4749         default:
4750           parmno = parmnum;
4751           break;
4752         }
4753
4754       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4755     }
4756
4757   if (warn_cxx_compat)
4758     {
4759       tree checktype = origtype != NULL_TREE ? origtype : rhstype;
4760       if (checktype != error_mark_node
4761           && TREE_CODE (type) == ENUMERAL_TYPE
4762           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (type))
4763         {
4764           WARN_FOR_ASSIGNMENT (input_location, OPT_Wc___compat,
4765                                G_("enum conversion when passing argument "
4766                                   "%d of %qE is invalid in C++"),
4767                                G_("enum conversion in assignment is "
4768                                   "invalid in C++"),
4769                                G_("enum conversion in initialization is "
4770                                   "invalid in C++"),
4771                                G_("enum conversion in return is "
4772                                   "invalid in C++"));
4773         }
4774     }
4775
4776   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4777     return rhs;
4778
4779   if (coder == VOID_TYPE)
4780     {
4781       /* Except for passing an argument to an unprototyped function,
4782          this is a constraint violation.  When passing an argument to
4783          an unprototyped function, it is compile-time undefined;
4784          making it a constraint in that case was rejected in
4785          DR#252.  */
4786       error_at (location, "void value not ignored as it ought to be");
4787       return error_mark_node;
4788     }
4789   rhs = require_complete_type (rhs);
4790   if (rhs == error_mark_node)
4791     return error_mark_node;
4792   /* A type converts to a reference to it.
4793      This code doesn't fully support references, it's just for the
4794      special case of va_start and va_copy.  */
4795   if (codel == REFERENCE_TYPE
4796       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4797     {
4798       if (!lvalue_p (rhs))
4799         {
4800           error_at (location, "cannot pass rvalue to reference parameter");
4801           return error_mark_node;
4802         }
4803       if (!c_mark_addressable (rhs))
4804         return error_mark_node;
4805       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4806       SET_EXPR_LOCATION (rhs, location);
4807
4808       /* We already know that these two types are compatible, but they
4809          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4810          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4811          likely to be va_list, a typedef to __builtin_va_list, which
4812          is different enough that it will cause problems later.  */
4813       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4814         {
4815           rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4816           SET_EXPR_LOCATION (rhs, location);
4817         }
4818
4819       rhs = build1 (NOP_EXPR, type, rhs);
4820       SET_EXPR_LOCATION (rhs, location);
4821       return rhs;
4822     }
4823   /* Some types can interconvert without explicit casts.  */
4824   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4825            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4826     return convert (type, rhs);
4827   /* Arithmetic types all interconvert, and enum is treated like int.  */
4828   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4829             || codel == FIXED_POINT_TYPE
4830             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4831             || codel == BOOLEAN_TYPE)
4832            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4833                || coder == FIXED_POINT_TYPE
4834                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4835                || coder == BOOLEAN_TYPE))
4836     {
4837       tree ret;
4838       bool save = in_late_binary_op;
4839       if (codel == BOOLEAN_TYPE)
4840         in_late_binary_op = true;
4841       ret = convert_and_check (type, orig_rhs);
4842       if (codel == BOOLEAN_TYPE)
4843         in_late_binary_op = save;
4844       return ret;
4845     }
4846
4847   /* Aggregates in different TUs might need conversion.  */
4848   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4849       && codel == coder
4850       && comptypes (type, rhstype))
4851     return convert_and_check (type, rhs);
4852
4853   /* Conversion to a transparent union from its member types.
4854      This applies only to function arguments.  */
4855   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4856       && errtype == ic_argpass)
4857     {
4858       tree memb, marginal_memb = NULL_TREE;
4859
4860       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4861         {
4862           tree memb_type = TREE_TYPE (memb);
4863
4864           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4865                          TYPE_MAIN_VARIANT (rhstype)))
4866             break;
4867
4868           if (TREE_CODE (memb_type) != POINTER_TYPE)
4869             continue;
4870
4871           if (coder == POINTER_TYPE)
4872             {
4873               tree ttl = TREE_TYPE (memb_type);
4874               tree ttr = TREE_TYPE (rhstype);
4875
4876               /* Any non-function converts to a [const][volatile] void *
4877                  and vice versa; otherwise, targets must be the same.
4878                  Meanwhile, the lhs target must have all the qualifiers of
4879                  the rhs.  */
4880               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4881                   || comp_target_types (location, memb_type, rhstype))
4882                 {
4883                   /* If this type won't generate any warnings, use it.  */
4884                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4885                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4886                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4887                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4888                              == TYPE_QUALS (ttr))
4889                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4890                              == TYPE_QUALS (ttl))))
4891                     break;
4892
4893                   /* Keep looking for a better type, but remember this one.  */
4894                   if (!marginal_memb)
4895                     marginal_memb = memb;
4896                 }
4897             }
4898
4899           /* Can convert integer zero to any pointer type.  */
4900           if (null_pointer_constant)
4901             {
4902               rhs = null_pointer_node;
4903               break;
4904             }
4905         }
4906
4907       if (memb || marginal_memb)
4908         {
4909           if (!memb)
4910             {
4911               /* We have only a marginally acceptable member type;
4912                  it needs a warning.  */
4913               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4914               tree ttr = TREE_TYPE (rhstype);
4915
4916               /* Const and volatile mean something different for function
4917                  types, so the usual warnings are not appropriate.  */
4918               if (TREE_CODE (ttr) == FUNCTION_TYPE
4919                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4920                 {
4921                   /* Because const and volatile on functions are
4922                      restrictions that say the function will not do
4923                      certain things, it is okay to use a const or volatile
4924                      function where an ordinary one is wanted, but not
4925                      vice-versa.  */
4926                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4927                     WARN_FOR_ASSIGNMENT (location, 0,
4928                                          G_("passing argument %d of %qE "
4929                                             "makes qualified function "
4930                                             "pointer from unqualified"),
4931                                          G_("assignment makes qualified "
4932                                             "function pointer from "
4933                                             "unqualified"),
4934                                          G_("initialization makes qualified "
4935                                             "function pointer from "
4936                                             "unqualified"),
4937                                          G_("return makes qualified function "
4938                                             "pointer from unqualified"));
4939                 }
4940               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4941                 WARN_FOR_ASSIGNMENT (location, 0,
4942                                      G_("passing argument %d of %qE discards "
4943                                         "qualifiers from pointer target type"),
4944                                      G_("assignment discards qualifiers "
4945                                         "from pointer target type"),
4946                                      G_("initialization discards qualifiers "
4947                                         "from pointer target type"),
4948                                      G_("return discards qualifiers from "
4949                                         "pointer target type"));
4950
4951               memb = marginal_memb;
4952             }
4953
4954           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4955             pedwarn (location, OPT_pedantic,
4956                      "ISO C prohibits argument conversion to union type");
4957
4958           rhs = fold_convert_loc (location, TREE_TYPE (memb), rhs);
4959           return build_constructor_single (type, memb, rhs);
4960         }
4961     }
4962
4963   /* Conversions among pointers */
4964   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4965            && (coder == codel))
4966     {
4967       tree ttl = TREE_TYPE (type);
4968       tree ttr = TREE_TYPE (rhstype);
4969       tree mvl = ttl;
4970       tree mvr = ttr;
4971       bool is_opaque_pointer;
4972       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4973
4974       if (TREE_CODE (mvl) != ARRAY_TYPE)
4975         mvl = TYPE_MAIN_VARIANT (mvl);
4976       if (TREE_CODE (mvr) != ARRAY_TYPE)
4977         mvr = TYPE_MAIN_VARIANT (mvr);
4978       /* Opaque pointers are treated like void pointers.  */
4979       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4980
4981       /* C++ does not allow the implicit conversion void* -> T*.  However,
4982          for the purpose of reducing the number of false positives, we
4983          tolerate the special case of
4984
4985                 int *p = NULL;
4986
4987          where NULL is typically defined in C to be '(void *) 0'.  */
4988       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4989         warning_at (location, OPT_Wc___compat,
4990                     "request for implicit conversion "
4991                     "from %qT to %qT not permitted in C++", rhstype, type);
4992
4993       /* Check if the right-hand side has a format attribute but the
4994          left-hand side doesn't.  */
4995       if (warn_missing_format_attribute
4996           && check_missing_format_attribute (type, rhstype))
4997         {
4998           switch (errtype)
4999           {
5000           case ic_argpass:
5001             warning_at (location, OPT_Wmissing_format_attribute,
5002                         "argument %d of %qE might be "
5003                         "a candidate for a format attribute",
5004                         parmnum, rname);
5005             break;
5006           case ic_assign:
5007             warning_at (location, OPT_Wmissing_format_attribute,
5008                         "assignment left-hand side might be "
5009                         "a candidate for a format attribute");
5010             break;
5011           case ic_init:
5012             warning_at (location, OPT_Wmissing_format_attribute,
5013                         "initialization left-hand side might be "
5014                         "a candidate for a format attribute");
5015             break;
5016           case ic_return:
5017             warning_at (location, OPT_Wmissing_format_attribute,
5018                         "return type might be "
5019                         "a candidate for a format attribute");
5020             break;
5021           default:
5022             gcc_unreachable ();
5023           }
5024         }
5025
5026       /* Any non-function converts to a [const][volatile] void *
5027          and vice versa; otherwise, targets must be the same.
5028          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
5029       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5030           || (target_cmp = comp_target_types (location, type, rhstype))
5031           || is_opaque_pointer
5032           || (c_common_unsigned_type (mvl)
5033               == c_common_unsigned_type (mvr)))
5034         {
5035           if (pedantic
5036               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
5037                   ||
5038                   (VOID_TYPE_P (ttr)
5039                    && !null_pointer_constant
5040                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
5041             WARN_FOR_ASSIGNMENT (location, OPT_pedantic,
5042                                  G_("ISO C forbids passing argument %d of "
5043                                     "%qE between function pointer "
5044                                     "and %<void *%>"),
5045                                  G_("ISO C forbids assignment between "
5046                                     "function pointer and %<void *%>"),
5047                                  G_("ISO C forbids initialization between "
5048                                     "function pointer and %<void *%>"),
5049                                  G_("ISO C forbids return between function "
5050                                     "pointer and %<void *%>"));
5051           /* Const and volatile mean something different for function types,
5052              so the usual warnings are not appropriate.  */
5053           else if (TREE_CODE (ttr) != FUNCTION_TYPE
5054                    && TREE_CODE (ttl) != FUNCTION_TYPE)
5055             {
5056               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
5057                 {
5058                   /* Types differing only by the presence of the 'volatile'
5059                      qualifier are acceptable if the 'volatile' has been added
5060                      in by the Objective-C EH machinery.  */
5061                   if (!objc_type_quals_match (ttl, ttr))
5062                     WARN_FOR_ASSIGNMENT (location, 0,
5063                                          G_("passing argument %d of %qE discards "
5064                                             "qualifiers from pointer target type"),
5065                                          G_("assignment discards qualifiers "
5066                                             "from pointer target type"),
5067                                          G_("initialization discards qualifiers "
5068                                             "from pointer target type"),
5069                                          G_("return discards qualifiers from "
5070                                             "pointer target type"));
5071                 }
5072               /* If this is not a case of ignoring a mismatch in signedness,
5073                  no warning.  */
5074               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5075                        || target_cmp)
5076                 ;
5077               /* If there is a mismatch, do warn.  */
5078               else if (warn_pointer_sign)
5079                 WARN_FOR_ASSIGNMENT (location, OPT_Wpointer_sign,
5080                                      G_("pointer targets in passing argument "
5081                                         "%d of %qE differ in signedness"),
5082                                      G_("pointer targets in assignment "
5083                                         "differ in signedness"),
5084                                      G_("pointer targets in initialization "
5085                                         "differ in signedness"),
5086                                      G_("pointer targets in return differ "
5087                                         "in signedness"));
5088             }
5089           else if (TREE_CODE (ttl) == FUNCTION_TYPE
5090                    && TREE_CODE (ttr) == FUNCTION_TYPE)
5091             {
5092               /* Because const and volatile on functions are restrictions
5093                  that say the function will not do certain things,
5094                  it is okay to use a const or volatile function
5095                  where an ordinary one is wanted, but not vice-versa.  */
5096               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
5097                 WARN_FOR_ASSIGNMENT (location, 0,
5098                                      G_("passing argument %d of %qE makes "
5099                                         "qualified function pointer "
5100                                         "from unqualified"),
5101                                      G_("assignment makes qualified function "
5102                                         "pointer from unqualified"),
5103                                      G_("initialization makes qualified "
5104                                         "function pointer from unqualified"),
5105                                      G_("return makes qualified function "
5106                                         "pointer from unqualified"));
5107             }
5108         }
5109       else
5110         /* Avoid warning about the volatile ObjC EH puts on decls.  */
5111         if (!objc_ok)
5112           WARN_FOR_ASSIGNMENT (location, 0,
5113                                G_("passing argument %d of %qE from "
5114                                   "incompatible pointer type"),
5115                                G_("assignment from incompatible pointer type"),
5116                                G_("initialization from incompatible "
5117                                   "pointer type"),
5118                                G_("return from incompatible pointer type"));
5119
5120       return convert (type, rhs);
5121     }
5122   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
5123     {
5124       /* ??? This should not be an error when inlining calls to
5125          unprototyped functions.  */
5126       error_at (location, "invalid use of non-lvalue array");
5127       return error_mark_node;
5128     }
5129   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
5130     {
5131       /* An explicit constant 0 can convert to a pointer,
5132          or one that results from arithmetic, even including
5133          a cast to integer type.  */
5134       if (!null_pointer_constant)
5135         WARN_FOR_ASSIGNMENT (location, 0,
5136                              G_("passing argument %d of %qE makes "
5137                                 "pointer from integer without a cast"),
5138                              G_("assignment makes pointer from integer "
5139                                 "without a cast"),
5140                              G_("initialization makes pointer from "
5141                                 "integer without a cast"),
5142                              G_("return makes pointer from integer "
5143                                 "without a cast"));
5144
5145       return convert (type, rhs);
5146     }
5147   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
5148     {
5149       WARN_FOR_ASSIGNMENT (location, 0,
5150                            G_("passing argument %d of %qE makes integer "
5151                               "from pointer without a cast"),
5152                            G_("assignment makes integer from pointer "
5153                               "without a cast"),
5154                            G_("initialization makes integer from pointer "
5155                               "without a cast"),
5156                            G_("return makes integer from pointer "
5157                               "without a cast"));
5158       return convert (type, rhs);
5159     }
5160   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
5161     {
5162       tree ret;
5163       bool save = in_late_binary_op;
5164       in_late_binary_op = true;
5165       ret = convert (type, rhs);
5166       in_late_binary_op = save;
5167       return ret;
5168     }
5169
5170   switch (errtype)
5171     {
5172     case ic_argpass:
5173       error_at (location, "incompatible type for argument %d of %qE", parmnum, rname);
5174       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
5175               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
5176               "expected %qT but argument is of type %qT", type, rhstype);
5177       break;
5178     case ic_assign:
5179       error_at (location, "incompatible types when assigning to type %qT from "
5180                 "type %qT", type, rhstype);
5181       break;
5182     case ic_init:
5183       error_at (location,
5184                 "incompatible types when initializing type %qT using type %qT",
5185                 type, rhstype);
5186       break;
5187     case ic_return:
5188       error_at (location,
5189                 "incompatible types when returning type %qT but %qT was "
5190                 "expected", rhstype, type);
5191       break;
5192     default:
5193       gcc_unreachable ();
5194     }
5195
5196   return error_mark_node;
5197 }
5198 \f
5199 /* If VALUE is a compound expr all of whose expressions are constant, then
5200    return its value.  Otherwise, return error_mark_node.
5201
5202    This is for handling COMPOUND_EXPRs as initializer elements
5203    which is allowed with a warning when -pedantic is specified.  */
5204
5205 static tree
5206 valid_compound_expr_initializer (tree value, tree endtype)
5207 {
5208   if (TREE_CODE (value) == COMPOUND_EXPR)
5209     {
5210       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
5211           == error_mark_node)
5212         return error_mark_node;
5213       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
5214                                               endtype);
5215     }
5216   else if (!initializer_constant_valid_p (value, endtype))
5217     return error_mark_node;
5218   else
5219     return value;
5220 }
5221 \f
5222 /* Perform appropriate conversions on the initial value of a variable,
5223    store it in the declaration DECL,
5224    and print any error messages that are appropriate.
5225    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5226    If the init is invalid, store an ERROR_MARK.
5227
5228    INIT_LOC is the location of the initial value.  */
5229
5230 void
5231 store_init_value (location_t init_loc, tree decl, tree init, tree origtype)
5232 {
5233   tree value, type;
5234   bool npc = false;
5235
5236   /* If variable's type was invalidly declared, just ignore it.  */
5237
5238   type = TREE_TYPE (decl);
5239   if (TREE_CODE (type) == ERROR_MARK)
5240     return;
5241
5242   /* Digest the specified initializer into an expression.  */
5243
5244   if (init)
5245     npc = null_pointer_constant_p (init);
5246   value = digest_init (init_loc, type, init, origtype, npc,
5247                        true, TREE_STATIC (decl));
5248
5249   /* Store the expression if valid; else report error.  */
5250
5251   if (!in_system_header
5252       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
5253     warning (OPT_Wtraditional, "traditional C rejects automatic "
5254              "aggregate initialization");
5255
5256   DECL_INITIAL (decl) = value;
5257
5258   /* ANSI wants warnings about out-of-range constant initializers.  */
5259   STRIP_TYPE_NOPS (value);
5260   if (TREE_STATIC (decl))
5261     constant_expression_warning (value);
5262
5263   /* Check if we need to set array size from compound literal size.  */
5264   if (TREE_CODE (type) == ARRAY_TYPE
5265       && TYPE_DOMAIN (type) == 0
5266       && value != error_mark_node)
5267     {
5268       tree inside_init = init;
5269
5270       STRIP_TYPE_NOPS (inside_init);
5271       inside_init = fold (inside_init);
5272
5273       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5274         {
5275           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5276
5277           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
5278             {
5279               /* For int foo[] = (int [3]){1}; we need to set array size
5280                  now since later on array initializer will be just the
5281                  brace enclosed list of the compound literal.  */
5282               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5283               TREE_TYPE (decl) = type;
5284               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
5285               layout_type (type);
5286               layout_decl (cldecl, 0);
5287             }
5288         }
5289     }
5290 }
5291 \f
5292 /* Methods for storing and printing names for error messages.  */
5293
5294 /* Implement a spelling stack that allows components of a name to be pushed
5295    and popped.  Each element on the stack is this structure.  */
5296
5297 struct spelling
5298 {
5299   int kind;
5300   union
5301     {
5302       unsigned HOST_WIDE_INT i;
5303       const char *s;
5304     } u;
5305 };
5306
5307 #define SPELLING_STRING 1
5308 #define SPELLING_MEMBER 2
5309 #define SPELLING_BOUNDS 3
5310
5311 static struct spelling *spelling;       /* Next stack element (unused).  */
5312 static struct spelling *spelling_base;  /* Spelling stack base.  */
5313 static int spelling_size;               /* Size of the spelling stack.  */
5314
5315 /* Macros to save and restore the spelling stack around push_... functions.
5316    Alternative to SAVE_SPELLING_STACK.  */
5317
5318 #define SPELLING_DEPTH() (spelling - spelling_base)
5319 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
5320
5321 /* Push an element on the spelling stack with type KIND and assign VALUE
5322    to MEMBER.  */
5323
5324 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
5325 {                                                                       \
5326   int depth = SPELLING_DEPTH ();                                        \
5327                                                                         \
5328   if (depth >= spelling_size)                                           \
5329     {                                                                   \
5330       spelling_size += 10;                                              \
5331       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
5332                                   spelling_size);                       \
5333       RESTORE_SPELLING_DEPTH (depth);                                   \
5334     }                                                                   \
5335                                                                         \
5336   spelling->kind = (KIND);                                              \
5337   spelling->MEMBER = (VALUE);                                           \
5338   spelling++;                                                           \
5339 }
5340
5341 /* Push STRING on the stack.  Printed literally.  */
5342
5343 static void
5344 push_string (const char *string)
5345 {
5346   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5347 }
5348
5349 /* Push a member name on the stack.  Printed as '.' STRING.  */
5350
5351 static void
5352 push_member_name (tree decl)
5353 {
5354   const char *const string
5355     = (DECL_NAME (decl)
5356        ? identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)))
5357        : _("<anonymous>"));
5358   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5359 }
5360
5361 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5362
5363 static void
5364 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5365 {
5366   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5367 }
5368
5369 /* Compute the maximum size in bytes of the printed spelling.  */
5370
5371 static int
5372 spelling_length (void)
5373 {
5374   int size = 0;
5375   struct spelling *p;
5376
5377   for (p = spelling_base; p < spelling; p++)
5378     {
5379       if (p->kind == SPELLING_BOUNDS)
5380         size += 25;
5381       else
5382         size += strlen (p->u.s) + 1;
5383     }
5384
5385   return size;
5386 }
5387
5388 /* Print the spelling to BUFFER and return it.  */
5389
5390 static char *
5391 print_spelling (char *buffer)
5392 {
5393   char *d = buffer;
5394   struct spelling *p;
5395
5396   for (p = spelling_base; p < spelling; p++)
5397     if (p->kind == SPELLING_BOUNDS)
5398       {
5399         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5400         d += strlen (d);
5401       }
5402     else
5403       {
5404         const char *s;
5405         if (p->kind == SPELLING_MEMBER)
5406           *d++ = '.';
5407         for (s = p->u.s; (*d = *s++); d++)
5408           ;
5409       }
5410   *d++ = '\0';
5411   return buffer;
5412 }
5413
5414 /* Issue an error message for a bad initializer component.
5415    MSGID identifies the message.
5416    The component name is taken from the spelling stack.  */
5417
5418 void
5419 error_init (const char *msgid)
5420 {
5421   char *ofwhat;
5422
5423   error ("%s", _(msgid));
5424   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5425   if (*ofwhat)
5426     error ("(near initialization for %qs)", ofwhat);
5427 }
5428
5429 /* Issue a pedantic warning for a bad initializer component.  OPT is
5430    the option OPT_* (from options.h) controlling this warning or 0 if
5431    it is unconditionally given.  MSGID identifies the message.  The
5432    component name is taken from the spelling stack.  */
5433
5434 void
5435 pedwarn_init (location_t location, int opt, const char *msgid)
5436 {
5437   char *ofwhat;
5438
5439   pedwarn (location, opt, "%s", _(msgid));
5440   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5441   if (*ofwhat)
5442     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5443 }
5444
5445 /* Issue a warning for a bad initializer component.
5446
5447    OPT is the OPT_W* value corresponding to the warning option that
5448    controls this warning.  MSGID identifies the message.  The
5449    component name is taken from the spelling stack.  */
5450
5451 static void
5452 warning_init (int opt, const char *msgid)
5453 {
5454   char *ofwhat;
5455
5456   warning (opt, "%s", _(msgid));
5457   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5458   if (*ofwhat)
5459     warning (opt, "(near initialization for %qs)", ofwhat);
5460 }
5461 \f
5462 /* If TYPE is an array type and EXPR is a parenthesized string
5463    constant, warn if pedantic that EXPR is being used to initialize an
5464    object of type TYPE.  */
5465
5466 void
5467 maybe_warn_string_init (tree type, struct c_expr expr)
5468 {
5469   if (pedantic
5470       && TREE_CODE (type) == ARRAY_TYPE
5471       && TREE_CODE (expr.value) == STRING_CST
5472       && expr.original_code != STRING_CST)
5473     pedwarn_init (input_location, OPT_pedantic,
5474                   "array initialized from parenthesized string constant");
5475 }
5476
5477 /* Digest the parser output INIT as an initializer for type TYPE.
5478    Return a C expression of type TYPE to represent the initial value.
5479
5480    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5481
5482    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
5483
5484    If INIT is a string constant, STRICT_STRING is true if it is
5485    unparenthesized or we should not warn here for it being parenthesized.
5486    For other types of INIT, STRICT_STRING is not used.
5487
5488    INIT_LOC is the location of the INIT.
5489
5490    REQUIRE_CONSTANT requests an error if non-constant initializers or
5491    elements are seen.  */
5492
5493 static tree
5494 digest_init (location_t init_loc, tree type, tree init, tree origtype,
5495              bool null_pointer_constant, bool strict_string,
5496              int require_constant)
5497 {
5498   enum tree_code code = TREE_CODE (type);
5499   tree inside_init = init;
5500   tree semantic_type = NULL_TREE;
5501   bool maybe_const = true;
5502
5503   if (type == error_mark_node
5504       || !init
5505       || init == error_mark_node
5506       || TREE_TYPE (init) == error_mark_node)
5507     return error_mark_node;
5508
5509   STRIP_TYPE_NOPS (inside_init);
5510
5511   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
5512     {
5513       semantic_type = TREE_TYPE (inside_init);
5514       inside_init = TREE_OPERAND (inside_init, 0);
5515     }
5516   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
5517   inside_init = decl_constant_value_for_optimization (inside_init);
5518
5519   /* Initialization of an array of chars from a string constant
5520      optionally enclosed in braces.  */
5521
5522   if (code == ARRAY_TYPE && inside_init
5523       && TREE_CODE (inside_init) == STRING_CST)
5524     {
5525       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5526       /* Note that an array could be both an array of character type
5527          and an array of wchar_t if wchar_t is signed char or unsigned
5528          char.  */
5529       bool char_array = (typ1 == char_type_node
5530                          || typ1 == signed_char_type_node
5531                          || typ1 == unsigned_char_type_node);
5532       bool wchar_array = !!comptypes (typ1, wchar_type_node);
5533       bool char16_array = !!comptypes (typ1, char16_type_node);
5534       bool char32_array = !!comptypes (typ1, char32_type_node);
5535
5536       if (char_array || wchar_array || char16_array || char32_array)
5537         {
5538           struct c_expr expr;
5539           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
5540           expr.value = inside_init;
5541           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
5542           expr.original_type = NULL;
5543           maybe_warn_string_init (type, expr);
5544
5545           if (TYPE_DOMAIN (type) && !TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
5546             pedwarn_init (init_loc, OPT_pedantic,
5547                           "initialization of a flexible array member");
5548
5549           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5550                          TYPE_MAIN_VARIANT (type)))
5551             return inside_init;
5552
5553           if (char_array)
5554             {
5555               if (typ2 != char_type_node)
5556                 {
5557                   error_init ("char-array initialized from wide string");
5558                   return error_mark_node;
5559                 }
5560             }
5561           else
5562             {
5563               if (typ2 == char_type_node)
5564                 {
5565                   error_init ("wide character array initialized from non-wide "
5566                               "string");
5567                   return error_mark_node;
5568                 }
5569               else if (!comptypes(typ1, typ2))
5570                 {
5571                   error_init ("wide character array initialized from "
5572                               "incompatible wide string");
5573                   return error_mark_node;
5574                 }
5575             }
5576
5577           TREE_TYPE (inside_init) = type;
5578           if (TYPE_DOMAIN (type) != 0
5579               && TYPE_SIZE (type) != 0
5580               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
5581             {
5582               unsigned HOST_WIDE_INT len = TREE_STRING_LENGTH (inside_init);
5583
5584               /* Subtract the size of a single (possibly wide) character
5585                  because it's ok to ignore the terminating null char
5586                  that is counted in the length of the constant.  */
5587               if (0 > compare_tree_int (TYPE_SIZE_UNIT (type),
5588                                         (len
5589                                          - (TYPE_PRECISION (typ1)
5590                                             / BITS_PER_UNIT))))
5591                 pedwarn_init (init_loc, 0,
5592                               ("initializer-string for array of chars "
5593                                "is too long"));
5594               else if (warn_cxx_compat
5595                        && 0 > compare_tree_int (TYPE_SIZE_UNIT (type), len))
5596                 warning_at (init_loc, OPT_Wc___compat,
5597                             ("initializer-string for array chars "
5598                              "is too long for C++"));
5599             }
5600
5601           return inside_init;
5602         }
5603       else if (INTEGRAL_TYPE_P (typ1))
5604         {
5605           error_init ("array of inappropriate type initialized "
5606                       "from string constant");
5607           return error_mark_node;
5608         }
5609     }
5610
5611   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
5612      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
5613      below and handle as a constructor.  */
5614   if (code == VECTOR_TYPE
5615       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
5616       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
5617       && TREE_CONSTANT (inside_init))
5618     {
5619       if (TREE_CODE (inside_init) == VECTOR_CST
5620           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5621                         TYPE_MAIN_VARIANT (type)))
5622         return inside_init;
5623
5624       if (TREE_CODE (inside_init) == CONSTRUCTOR)
5625         {
5626           unsigned HOST_WIDE_INT ix;
5627           tree value;
5628           bool constant_p = true;
5629
5630           /* Iterate through elements and check if all constructor
5631              elements are *_CSTs.  */
5632           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
5633             if (!CONSTANT_CLASS_P (value))
5634               {
5635                 constant_p = false;
5636                 break;
5637               }
5638
5639           if (constant_p)
5640             return build_vector_from_ctor (type,
5641                                            CONSTRUCTOR_ELTS (inside_init));
5642         }
5643     }
5644
5645   if (warn_sequence_point)
5646     verify_sequence_points (inside_init);
5647
5648   /* Any type can be initialized
5649      from an expression of the same type, optionally with braces.  */
5650
5651   if (inside_init && TREE_TYPE (inside_init) != 0
5652       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5653                      TYPE_MAIN_VARIANT (type))
5654           || (code == ARRAY_TYPE
5655               && comptypes (TREE_TYPE (inside_init), type))
5656           || (code == VECTOR_TYPE
5657               && comptypes (TREE_TYPE (inside_init), type))
5658           || (code == POINTER_TYPE
5659               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
5660               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
5661                             TREE_TYPE (type)))))
5662     {
5663       if (code == POINTER_TYPE)
5664         {
5665           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
5666             {
5667               if (TREE_CODE (inside_init) == STRING_CST
5668                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5669                 inside_init = array_to_pointer_conversion
5670                   (init_loc, inside_init);
5671               else
5672                 {
5673                   error_init ("invalid use of non-lvalue array");
5674                   return error_mark_node;
5675                 }
5676             }
5677         }
5678
5679       if (code == VECTOR_TYPE)
5680         /* Although the types are compatible, we may require a
5681            conversion.  */
5682         inside_init = convert (type, inside_init);
5683
5684       if (require_constant
5685           && (code == VECTOR_TYPE || !flag_isoc99)
5686           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5687         {
5688           /* As an extension, allow initializing objects with static storage
5689              duration with compound literals (which are then treated just as
5690              the brace enclosed list they contain).  Also allow this for
5691              vectors, as we can only assign them with compound literals.  */
5692           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5693           inside_init = DECL_INITIAL (decl);
5694         }
5695
5696       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
5697           && TREE_CODE (inside_init) != CONSTRUCTOR)
5698         {
5699           error_init ("array initialized from non-constant array expression");
5700           return error_mark_node;
5701         }
5702
5703       /* Compound expressions can only occur here if -pedantic or
5704          -pedantic-errors is specified.  In the later case, we always want
5705          an error.  In the former case, we simply want a warning.  */
5706       if (require_constant && pedantic
5707           && TREE_CODE (inside_init) == COMPOUND_EXPR)
5708         {
5709           inside_init
5710             = valid_compound_expr_initializer (inside_init,
5711                                                TREE_TYPE (inside_init));
5712           if (inside_init == error_mark_node)
5713             error_init ("initializer element is not constant");
5714           else
5715             pedwarn_init (init_loc, OPT_pedantic,
5716                           "initializer element is not constant");
5717           if (flag_pedantic_errors)
5718             inside_init = error_mark_node;
5719         }
5720       else if (require_constant
5721                && !initializer_constant_valid_p (inside_init,
5722                                                  TREE_TYPE (inside_init)))
5723         {
5724           error_init ("initializer element is not constant");
5725           inside_init = error_mark_node;
5726         }
5727       else if (require_constant && !maybe_const)
5728         pedwarn_init (init_loc, 0,
5729                       "initializer element is not a constant expression");
5730
5731       /* Added to enable additional -Wmissing-format-attribute warnings.  */
5732       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
5733         inside_init = convert_for_assignment (init_loc, type, inside_init,
5734                                               origtype,
5735                                               ic_init, null_pointer_constant,
5736                                               NULL_TREE, NULL_TREE, 0);
5737       return inside_init;
5738     }
5739
5740   /* Handle scalar types, including conversions.  */
5741
5742   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
5743       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
5744       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
5745     {
5746       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
5747           && (TREE_CODE (init) == STRING_CST
5748               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
5749         inside_init = init = array_to_pointer_conversion (init_loc, init);
5750       if (semantic_type)
5751         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
5752                               inside_init);
5753       inside_init
5754         = convert_for_assignment (init_loc, type, inside_init, origtype,
5755                                   ic_init, null_pointer_constant,
5756                                   NULL_TREE, NULL_TREE, 0);
5757
5758       /* Check to see if we have already given an error message.  */
5759       if (inside_init == error_mark_node)
5760         ;
5761       else if (require_constant && !TREE_CONSTANT (inside_init))
5762         {
5763           error_init ("initializer element is not constant");
5764           inside_init = error_mark_node;
5765         }
5766       else if (require_constant
5767                && !initializer_constant_valid_p (inside_init,
5768                                                  TREE_TYPE (inside_init)))
5769         {
5770           error_init ("initializer element is not computable at load time");
5771           inside_init = error_mark_node;
5772         }
5773       else if (require_constant && !maybe_const)
5774         pedwarn_init (init_loc, 0,
5775                       "initializer element is not a constant expression");
5776
5777       return inside_init;
5778     }
5779
5780   /* Come here only for records and arrays.  */
5781
5782   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5783     {
5784       error_init ("variable-sized object may not be initialized");
5785       return error_mark_node;
5786     }
5787
5788   error_init ("invalid initializer");
5789   return error_mark_node;
5790 }
5791 \f
5792 /* Handle initializers that use braces.  */
5793
5794 /* Type of object we are accumulating a constructor for.
5795    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5796 static tree constructor_type;
5797
5798 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
5799    left to fill.  */
5800 static tree constructor_fields;
5801
5802 /* For an ARRAY_TYPE, this is the specified index
5803    at which to store the next element we get.  */
5804 static tree constructor_index;
5805
5806 /* For an ARRAY_TYPE, this is the maximum index.  */
5807 static tree constructor_max_index;
5808
5809 /* For a RECORD_TYPE, this is the first field not yet written out.  */
5810 static tree constructor_unfilled_fields;
5811
5812 /* For an ARRAY_TYPE, this is the index of the first element
5813    not yet written out.  */
5814 static tree constructor_unfilled_index;
5815
5816 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5817    This is so we can generate gaps between fields, when appropriate.  */
5818 static tree constructor_bit_index;
5819
5820 /* If we are saving up the elements rather than allocating them,
5821    this is the list of elements so far (in reverse order,
5822    most recent first).  */
5823 static VEC(constructor_elt,gc) *constructor_elements;
5824
5825 /* 1 if constructor should be incrementally stored into a constructor chain,
5826    0 if all the elements should be kept in AVL tree.  */
5827 static int constructor_incremental;
5828
5829 /* 1 if so far this constructor's elements are all compile-time constants.  */
5830 static int constructor_constant;
5831
5832 /* 1 if so far this constructor's elements are all valid address constants.  */
5833 static int constructor_simple;
5834
5835 /* 1 if this constructor has an element that cannot be part of a
5836    constant expression.  */
5837 static int constructor_nonconst;
5838
5839 /* 1 if this constructor is erroneous so far.  */
5840 static int constructor_erroneous;
5841
5842 /* Structure for managing pending initializer elements, organized as an
5843    AVL tree.  */
5844
5845 struct init_node
5846 {
5847   struct init_node *left, *right;
5848   struct init_node *parent;
5849   int balance;
5850   tree purpose;
5851   tree value;
5852   tree origtype;
5853 };
5854
5855 /* Tree of pending elements at this constructor level.
5856    These are elements encountered out of order
5857    which belong at places we haven't reached yet in actually
5858    writing the output.
5859    Will never hold tree nodes across GC runs.  */
5860 static struct init_node *constructor_pending_elts;
5861
5862 /* The SPELLING_DEPTH of this constructor.  */
5863 static int constructor_depth;
5864
5865 /* DECL node for which an initializer is being read.
5866    0 means we are reading a constructor expression
5867    such as (struct foo) {...}.  */
5868 static tree constructor_decl;
5869
5870 /* Nonzero if this is an initializer for a top-level decl.  */
5871 static int constructor_top_level;
5872
5873 /* Nonzero if there were any member designators in this initializer.  */
5874 static int constructor_designated;
5875
5876 /* Nesting depth of designator list.  */
5877 static int designator_depth;
5878
5879 /* Nonzero if there were diagnosed errors in this designator list.  */
5880 static int designator_erroneous;
5881
5882 \f
5883 /* This stack has a level for each implicit or explicit level of
5884    structuring in the initializer, including the outermost one.  It
5885    saves the values of most of the variables above.  */
5886
5887 struct constructor_range_stack;
5888
5889 struct constructor_stack
5890 {
5891   struct constructor_stack *next;
5892   tree type;
5893   tree fields;
5894   tree index;
5895   tree max_index;
5896   tree unfilled_index;
5897   tree unfilled_fields;
5898   tree bit_index;
5899   VEC(constructor_elt,gc) *elements;
5900   struct init_node *pending_elts;
5901   int offset;
5902   int depth;
5903   /* If value nonzero, this value should replace the entire
5904      constructor at this level.  */
5905   struct c_expr replacement_value;
5906   struct constructor_range_stack *range_stack;
5907   char constant;
5908   char simple;
5909   char nonconst;
5910   char implicit;
5911   char erroneous;
5912   char outer;
5913   char incremental;
5914   char designated;
5915 };
5916
5917 static struct constructor_stack *constructor_stack;
5918
5919 /* This stack represents designators from some range designator up to
5920    the last designator in the list.  */
5921
5922 struct constructor_range_stack
5923 {
5924   struct constructor_range_stack *next, *prev;
5925   struct constructor_stack *stack;
5926   tree range_start;
5927   tree index;
5928   tree range_end;
5929   tree fields;
5930 };
5931
5932 static struct constructor_range_stack *constructor_range_stack;
5933
5934 /* This stack records separate initializers that are nested.
5935    Nested initializers can't happen in ANSI C, but GNU C allows them
5936    in cases like { ... (struct foo) { ... } ... }.  */
5937
5938 struct initializer_stack
5939 {
5940   struct initializer_stack *next;
5941   tree decl;
5942   struct constructor_stack *constructor_stack;
5943   struct constructor_range_stack *constructor_range_stack;
5944   VEC(constructor_elt,gc) *elements;
5945   struct spelling *spelling;
5946   struct spelling *spelling_base;
5947   int spelling_size;
5948   char top_level;
5949   char require_constant_value;
5950   char require_constant_elements;
5951 };
5952
5953 static struct initializer_stack *initializer_stack;
5954 \f
5955 /* Prepare to parse and output the initializer for variable DECL.  */
5956
5957 void
5958 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5959 {
5960   const char *locus;
5961   struct initializer_stack *p = XNEW (struct initializer_stack);
5962
5963   p->decl = constructor_decl;
5964   p->require_constant_value = require_constant_value;
5965   p->require_constant_elements = require_constant_elements;
5966   p->constructor_stack = constructor_stack;
5967   p->constructor_range_stack = constructor_range_stack;
5968   p->elements = constructor_elements;
5969   p->spelling = spelling;
5970   p->spelling_base = spelling_base;
5971   p->spelling_size = spelling_size;
5972   p->top_level = constructor_top_level;
5973   p->next = initializer_stack;
5974   initializer_stack = p;
5975
5976   constructor_decl = decl;
5977   constructor_designated = 0;
5978   constructor_top_level = top_level;
5979
5980   if (decl != 0 && decl != error_mark_node)
5981     {
5982       require_constant_value = TREE_STATIC (decl);
5983       require_constant_elements
5984         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5985            /* For a scalar, you can always use any value to initialize,
5986               even within braces.  */
5987            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5988                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5989                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5990                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5991       locus = identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)));
5992     }
5993   else
5994     {
5995       require_constant_value = 0;
5996       require_constant_elements = 0;
5997       locus = _("(anonymous)");
5998     }
5999
6000   constructor_stack = 0;
6001   constructor_range_stack = 0;
6002
6003   missing_braces_mentioned = 0;
6004
6005   spelling_base = 0;
6006   spelling_size = 0;
6007   RESTORE_SPELLING_DEPTH (0);
6008
6009   if (locus)
6010     push_string (locus);
6011 }
6012
6013 void
6014 finish_init (void)
6015 {
6016   struct initializer_stack *p = initializer_stack;
6017
6018   /* Free the whole constructor stack of this initializer.  */
6019   while (constructor_stack)
6020     {
6021       struct constructor_stack *q = constructor_stack;
6022       constructor_stack = q->next;
6023       free (q);
6024     }
6025
6026   gcc_assert (!constructor_range_stack);
6027
6028   /* Pop back to the data of the outer initializer (if any).  */
6029   free (spelling_base);
6030
6031   constructor_decl = p->decl;
6032   require_constant_value = p->require_constant_value;
6033   require_constant_elements = p->require_constant_elements;
6034   constructor_stack = p->constructor_stack;
6035   constructor_range_stack = p->constructor_range_stack;
6036   constructor_elements = p->elements;
6037   spelling = p->spelling;
6038   spelling_base = p->spelling_base;
6039   spelling_size = p->spelling_size;
6040   constructor_top_level = p->top_level;
6041   initializer_stack = p->next;
6042   free (p);
6043 }
6044 \f
6045 /* Call here when we see the initializer is surrounded by braces.
6046    This is instead of a call to push_init_level;
6047    it is matched by a call to pop_init_level.
6048
6049    TYPE is the type to initialize, for a constructor expression.
6050    For an initializer for a decl, TYPE is zero.  */
6051
6052 void
6053 really_start_incremental_init (tree type)
6054 {
6055   struct constructor_stack *p = XNEW (struct constructor_stack);
6056
6057   if (type == 0)
6058     type = TREE_TYPE (constructor_decl);
6059
6060   if (TREE_CODE (type) == VECTOR_TYPE
6061       && TYPE_VECTOR_OPAQUE (type))
6062     error ("opaque vector types cannot be initialized");
6063
6064   p->type = constructor_type;
6065   p->fields = constructor_fields;
6066   p->index = constructor_index;
6067   p->max_index = constructor_max_index;
6068   p->unfilled_index = constructor_unfilled_index;
6069   p->unfilled_fields = constructor_unfilled_fields;
6070   p->bit_index = constructor_bit_index;
6071   p->elements = constructor_elements;
6072   p->constant = constructor_constant;
6073   p->simple = constructor_simple;
6074   p->nonconst = constructor_nonconst;
6075   p->erroneous = constructor_erroneous;
6076   p->pending_elts = constructor_pending_elts;
6077   p->depth = constructor_depth;
6078   p->replacement_value.value = 0;
6079   p->replacement_value.original_code = ERROR_MARK;
6080   p->replacement_value.original_type = NULL;
6081   p->implicit = 0;
6082   p->range_stack = 0;
6083   p->outer = 0;
6084   p->incremental = constructor_incremental;
6085   p->designated = constructor_designated;
6086   p->next = 0;
6087   constructor_stack = p;
6088
6089   constructor_constant = 1;
6090   constructor_simple = 1;
6091   constructor_nonconst = 0;
6092   constructor_depth = SPELLING_DEPTH ();
6093   constructor_elements = 0;
6094   constructor_pending_elts = 0;
6095   constructor_type = type;
6096   constructor_incremental = 1;
6097   constructor_designated = 0;
6098   designator_depth = 0;
6099   designator_erroneous = 0;
6100
6101   if (TREE_CODE (constructor_type) == RECORD_TYPE
6102       || TREE_CODE (constructor_type) == UNION_TYPE)
6103     {
6104       constructor_fields = TYPE_FIELDS (constructor_type);
6105       /* Skip any nameless bit fields at the beginning.  */
6106       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6107              && DECL_NAME (constructor_fields) == 0)
6108         constructor_fields = TREE_CHAIN (constructor_fields);
6109
6110       constructor_unfilled_fields = constructor_fields;
6111       constructor_bit_index = bitsize_zero_node;
6112     }
6113   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6114     {
6115       if (TYPE_DOMAIN (constructor_type))
6116         {
6117           constructor_max_index
6118             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6119
6120           /* Detect non-empty initializations of zero-length arrays.  */
6121           if (constructor_max_index == NULL_TREE
6122               && TYPE_SIZE (constructor_type))
6123             constructor_max_index = build_int_cst (NULL_TREE, -1);
6124
6125           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6126              to initialize VLAs will cause a proper error; avoid tree
6127              checking errors as well by setting a safe value.  */
6128           if (constructor_max_index
6129               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6130             constructor_max_index = build_int_cst (NULL_TREE, -1);
6131
6132           constructor_index
6133             = convert (bitsizetype,
6134                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6135         }
6136       else
6137         {
6138           constructor_index = bitsize_zero_node;
6139           constructor_max_index = NULL_TREE;
6140         }
6141
6142       constructor_unfilled_index = constructor_index;
6143     }
6144   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6145     {
6146       /* Vectors are like simple fixed-size arrays.  */
6147       constructor_max_index =
6148         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6149       constructor_index = bitsize_zero_node;
6150       constructor_unfilled_index = constructor_index;
6151     }
6152   else
6153     {
6154       /* Handle the case of int x = {5}; */
6155       constructor_fields = constructor_type;
6156       constructor_unfilled_fields = constructor_type;
6157     }
6158 }
6159 \f
6160 /* Push down into a subobject, for initialization.
6161    If this is for an explicit set of braces, IMPLICIT is 0.
6162    If it is because the next element belongs at a lower level,
6163    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
6164
6165 void
6166 push_init_level (int implicit)
6167 {
6168   struct constructor_stack *p;
6169   tree value = NULL_TREE;
6170
6171   /* If we've exhausted any levels that didn't have braces,
6172      pop them now.  If implicit == 1, this will have been done in
6173      process_init_element; do not repeat it here because in the case
6174      of excess initializers for an empty aggregate this leads to an
6175      infinite cycle of popping a level and immediately recreating
6176      it.  */
6177   if (implicit != 1)
6178     {
6179       while (constructor_stack->implicit)
6180         {
6181           if ((TREE_CODE (constructor_type) == RECORD_TYPE
6182                || TREE_CODE (constructor_type) == UNION_TYPE)
6183               && constructor_fields == 0)
6184             process_init_element (pop_init_level (1), true);
6185           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6186                    && constructor_max_index
6187                    && tree_int_cst_lt (constructor_max_index,
6188                                        constructor_index))
6189             process_init_element (pop_init_level (1), true);
6190           else
6191             break;
6192         }
6193     }
6194
6195   /* Unless this is an explicit brace, we need to preserve previous
6196      content if any.  */
6197   if (implicit)
6198     {
6199       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6200            || TREE_CODE (constructor_type) == UNION_TYPE)
6201           && constructor_fields)
6202         value = find_init_member (constructor_fields);
6203       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6204         value = find_init_member (constructor_index);
6205     }
6206
6207   p = XNEW (struct constructor_stack);
6208   p->type = constructor_type;
6209   p->fields = constructor_fields;
6210   p->index = constructor_index;
6211   p->max_index = constructor_max_index;
6212   p->unfilled_index = constructor_unfilled_index;
6213   p->unfilled_fields = constructor_unfilled_fields;
6214   p->bit_index = constructor_bit_index;
6215   p->elements = constructor_elements;
6216   p->constant = constructor_constant;
6217   p->simple = constructor_simple;
6218   p->nonconst = constructor_nonconst;
6219   p->erroneous = constructor_erroneous;
6220   p->pending_elts = constructor_pending_elts;
6221   p->depth = constructor_depth;
6222   p->replacement_value.value = 0;
6223   p->replacement_value.original_code = ERROR_MARK;
6224   p->replacement_value.original_type = NULL;
6225   p->implicit = implicit;
6226   p->outer = 0;
6227   p->incremental = constructor_incremental;
6228   p->designated = constructor_designated;
6229   p->next = constructor_stack;
6230   p->range_stack = 0;
6231   constructor_stack = p;
6232
6233   constructor_constant = 1;
6234   constructor_simple = 1;
6235   constructor_nonconst = 0;
6236   constructor_depth = SPELLING_DEPTH ();
6237   constructor_elements = 0;
6238   constructor_incremental = 1;
6239   constructor_designated = 0;
6240   constructor_pending_elts = 0;
6241   if (!implicit)
6242     {
6243       p->range_stack = constructor_range_stack;
6244       constructor_range_stack = 0;
6245       designator_depth = 0;
6246       designator_erroneous = 0;
6247     }
6248
6249   /* Don't die if an entire brace-pair level is superfluous
6250      in the containing level.  */
6251   if (constructor_type == 0)
6252     ;
6253   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6254            || TREE_CODE (constructor_type) == UNION_TYPE)
6255     {
6256       /* Don't die if there are extra init elts at the end.  */
6257       if (constructor_fields == 0)
6258         constructor_type = 0;
6259       else
6260         {
6261           constructor_type = TREE_TYPE (constructor_fields);
6262           push_member_name (constructor_fields);
6263           constructor_depth++;
6264         }
6265     }
6266   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6267     {
6268       constructor_type = TREE_TYPE (constructor_type);
6269       push_array_bounds (tree_low_cst (constructor_index, 1));
6270       constructor_depth++;
6271     }
6272
6273   if (constructor_type == 0)
6274     {
6275       error_init ("extra brace group at end of initializer");
6276       constructor_fields = 0;
6277       constructor_unfilled_fields = 0;
6278       return;
6279     }
6280
6281   if (value && TREE_CODE (value) == CONSTRUCTOR)
6282     {
6283       constructor_constant = TREE_CONSTANT (value);
6284       constructor_simple = TREE_STATIC (value);
6285       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
6286       constructor_elements = CONSTRUCTOR_ELTS (value);
6287       if (!VEC_empty (constructor_elt, constructor_elements)
6288           && (TREE_CODE (constructor_type) == RECORD_TYPE
6289               || TREE_CODE (constructor_type) == ARRAY_TYPE))
6290         set_nonincremental_init ();
6291     }
6292
6293   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
6294     {
6295       missing_braces_mentioned = 1;
6296       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
6297     }
6298
6299   if (TREE_CODE (constructor_type) == RECORD_TYPE
6300            || TREE_CODE (constructor_type) == UNION_TYPE)
6301     {
6302       constructor_fields = TYPE_FIELDS (constructor_type);
6303       /* Skip any nameless bit fields at the beginning.  */
6304       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6305              && DECL_NAME (constructor_fields) == 0)
6306         constructor_fields = TREE_CHAIN (constructor_fields);
6307
6308       constructor_unfilled_fields = constructor_fields;
6309       constructor_bit_index = bitsize_zero_node;
6310     }
6311   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6312     {
6313       /* Vectors are like simple fixed-size arrays.  */
6314       constructor_max_index =
6315         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6316       constructor_index = convert (bitsizetype, integer_zero_node);
6317       constructor_unfilled_index = constructor_index;
6318     }
6319   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6320     {
6321       if (TYPE_DOMAIN (constructor_type))
6322         {
6323           constructor_max_index
6324             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6325
6326           /* Detect non-empty initializations of zero-length arrays.  */
6327           if (constructor_max_index == NULL_TREE
6328               && TYPE_SIZE (constructor_type))
6329             constructor_max_index = build_int_cst (NULL_TREE, -1);
6330
6331           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6332              to initialize VLAs will cause a proper error; avoid tree
6333              checking errors as well by setting a safe value.  */
6334           if (constructor_max_index
6335               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6336             constructor_max_index = build_int_cst (NULL_TREE, -1);
6337
6338           constructor_index
6339             = convert (bitsizetype,
6340                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6341         }
6342       else
6343         constructor_index = bitsize_zero_node;
6344
6345       constructor_unfilled_index = constructor_index;
6346       if (value && TREE_CODE (value) == STRING_CST)
6347         {
6348           /* We need to split the char/wchar array into individual
6349              characters, so that we don't have to special case it
6350              everywhere.  */
6351           set_nonincremental_init_from_string (value);
6352         }
6353     }
6354   else
6355     {
6356       if (constructor_type != error_mark_node)
6357         warning_init (0, "braces around scalar initializer");
6358       constructor_fields = constructor_type;
6359       constructor_unfilled_fields = constructor_type;
6360     }
6361 }
6362
6363 /* At the end of an implicit or explicit brace level,
6364    finish up that level of constructor.  If a single expression
6365    with redundant braces initialized that level, return the
6366    c_expr structure for that expression.  Otherwise, the original_code
6367    element is set to ERROR_MARK.
6368    If we were outputting the elements as they are read, return 0 as the value
6369    from inner levels (process_init_element ignores that),
6370    but return error_mark_node as the value from the outermost level
6371    (that's what we want to put in DECL_INITIAL).
6372    Otherwise, return a CONSTRUCTOR expression as the value.  */
6373
6374 struct c_expr
6375 pop_init_level (int implicit)
6376 {
6377   struct constructor_stack *p;
6378   struct c_expr ret;
6379   ret.value = 0;
6380   ret.original_code = ERROR_MARK;
6381   ret.original_type = NULL;
6382
6383   if (implicit == 0)
6384     {
6385       /* When we come to an explicit close brace,
6386          pop any inner levels that didn't have explicit braces.  */
6387       while (constructor_stack->implicit)
6388         process_init_element (pop_init_level (1), true);
6389
6390       gcc_assert (!constructor_range_stack);
6391     }
6392
6393   /* Now output all pending elements.  */
6394   constructor_incremental = 1;
6395   output_pending_init_elements (1);
6396
6397   p = constructor_stack;
6398
6399   /* Error for initializing a flexible array member, or a zero-length
6400      array member in an inappropriate context.  */
6401   if (constructor_type && constructor_fields
6402       && TREE_CODE (constructor_type) == ARRAY_TYPE
6403       && TYPE_DOMAIN (constructor_type)
6404       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6405     {
6406       /* Silently discard empty initializations.  The parser will
6407          already have pedwarned for empty brackets.  */
6408       if (integer_zerop (constructor_unfilled_index))
6409         constructor_type = NULL_TREE;
6410       else
6411         {
6412           gcc_assert (!TYPE_SIZE (constructor_type));
6413
6414           if (constructor_depth > 2)
6415             error_init ("initialization of flexible array member in a nested context");
6416           else
6417             pedwarn_init (input_location, OPT_pedantic,
6418                           "initialization of a flexible array member");
6419
6420           /* We have already issued an error message for the existence
6421              of a flexible array member not at the end of the structure.
6422              Discard the initializer so that we do not die later.  */
6423           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
6424             constructor_type = NULL_TREE;
6425         }
6426     }
6427
6428   /* Warn when some struct elements are implicitly initialized to zero.  */
6429   if (warn_missing_field_initializers
6430       && constructor_type
6431       && TREE_CODE (constructor_type) == RECORD_TYPE
6432       && constructor_unfilled_fields)
6433     {
6434         /* Do not warn for flexible array members or zero-length arrays.  */
6435         while (constructor_unfilled_fields
6436                && (!DECL_SIZE (constructor_unfilled_fields)
6437                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6438           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6439
6440         /* Do not warn if this level of the initializer uses member
6441            designators; it is likely to be deliberate.  */
6442         if (constructor_unfilled_fields && !constructor_designated)
6443           {
6444             push_member_name (constructor_unfilled_fields);
6445             warning_init (OPT_Wmissing_field_initializers,
6446                           "missing initializer");
6447             RESTORE_SPELLING_DEPTH (constructor_depth);
6448           }
6449     }
6450
6451   /* Pad out the end of the structure.  */
6452   if (p->replacement_value.value)
6453     /* If this closes a superfluous brace pair,
6454        just pass out the element between them.  */
6455     ret = p->replacement_value;
6456   else if (constructor_type == 0)
6457     ;
6458   else if (TREE_CODE (constructor_type) != RECORD_TYPE
6459            && TREE_CODE (constructor_type) != UNION_TYPE
6460            && TREE_CODE (constructor_type) != ARRAY_TYPE
6461            && TREE_CODE (constructor_type) != VECTOR_TYPE)
6462     {
6463       /* A nonincremental scalar initializer--just return
6464          the element, after verifying there is just one.  */
6465       if (VEC_empty (constructor_elt,constructor_elements))
6466         {
6467           if (!constructor_erroneous)
6468             error_init ("empty scalar initializer");
6469           ret.value = error_mark_node;
6470         }
6471       else if (VEC_length (constructor_elt,constructor_elements) != 1)
6472         {
6473           error_init ("extra elements in scalar initializer");
6474           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6475         }
6476       else
6477         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6478     }
6479   else
6480     {
6481       if (constructor_erroneous)
6482         ret.value = error_mark_node;
6483       else
6484         {
6485           ret.value = build_constructor (constructor_type,
6486                                          constructor_elements);
6487           if (constructor_constant)
6488             TREE_CONSTANT (ret.value) = 1;
6489           if (constructor_constant && constructor_simple)
6490             TREE_STATIC (ret.value) = 1;
6491           if (constructor_nonconst)
6492             CONSTRUCTOR_NON_CONST (ret.value) = 1;
6493         }
6494     }
6495
6496   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
6497     {
6498       if (constructor_nonconst)
6499         ret.original_code = C_MAYBE_CONST_EXPR;
6500       else if (ret.original_code == C_MAYBE_CONST_EXPR)
6501         ret.original_code = ERROR_MARK;
6502     }
6503
6504   constructor_type = p->type;
6505   constructor_fields = p->fields;
6506   constructor_index = p->index;
6507   constructor_max_index = p->max_index;
6508   constructor_unfilled_index = p->unfilled_index;
6509   constructor_unfilled_fields = p->unfilled_fields;
6510   constructor_bit_index = p->bit_index;
6511   constructor_elements = p->elements;
6512   constructor_constant = p->constant;
6513   constructor_simple = p->simple;
6514   constructor_nonconst = p->nonconst;
6515   constructor_erroneous = p->erroneous;
6516   constructor_incremental = p->incremental;
6517   constructor_designated = p->designated;
6518   constructor_pending_elts = p->pending_elts;
6519   constructor_depth = p->depth;
6520   if (!p->implicit)
6521     constructor_range_stack = p->range_stack;
6522   RESTORE_SPELLING_DEPTH (constructor_depth);
6523
6524   constructor_stack = p->next;
6525   free (p);
6526
6527   if (ret.value == 0 && constructor_stack == 0)
6528     ret.value = error_mark_node;
6529   return ret;
6530 }
6531
6532 /* Common handling for both array range and field name designators.
6533    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
6534
6535 static int
6536 set_designator (int array)
6537 {
6538   tree subtype;
6539   enum tree_code subcode;
6540
6541   /* Don't die if an entire brace-pair level is superfluous
6542      in the containing level.  */
6543   if (constructor_type == 0)
6544     return 1;
6545
6546   /* If there were errors in this designator list already, bail out
6547      silently.  */
6548   if (designator_erroneous)
6549     return 1;
6550
6551   if (!designator_depth)
6552     {
6553       gcc_assert (!constructor_range_stack);
6554
6555       /* Designator list starts at the level of closest explicit
6556          braces.  */
6557       while (constructor_stack->implicit)
6558         process_init_element (pop_init_level (1), true);
6559       constructor_designated = 1;
6560       return 0;
6561     }
6562
6563   switch (TREE_CODE (constructor_type))
6564     {
6565     case  RECORD_TYPE:
6566     case  UNION_TYPE:
6567       subtype = TREE_TYPE (constructor_fields);
6568       if (subtype != error_mark_node)
6569         subtype = TYPE_MAIN_VARIANT (subtype);
6570       break;
6571     case ARRAY_TYPE:
6572       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6573       break;
6574     default:
6575       gcc_unreachable ();
6576     }
6577
6578   subcode = TREE_CODE (subtype);
6579   if (array && subcode != ARRAY_TYPE)
6580     {
6581       error_init ("array index in non-array initializer");
6582       return 1;
6583     }
6584   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
6585     {
6586       error_init ("field name not in record or union initializer");
6587       return 1;
6588     }
6589
6590   constructor_designated = 1;
6591   push_init_level (2);
6592   return 0;
6593 }
6594
6595 /* If there are range designators in designator list, push a new designator
6596    to constructor_range_stack.  RANGE_END is end of such stack range or
6597    NULL_TREE if there is no range designator at this level.  */
6598
6599 static void
6600 push_range_stack (tree range_end)
6601 {
6602   struct constructor_range_stack *p;
6603
6604   p = GGC_NEW (struct constructor_range_stack);
6605   p->prev = constructor_range_stack;
6606   p->next = 0;
6607   p->fields = constructor_fields;
6608   p->range_start = constructor_index;
6609   p->index = constructor_index;
6610   p->stack = constructor_stack;
6611   p->range_end = range_end;
6612   if (constructor_range_stack)
6613     constructor_range_stack->next = p;
6614   constructor_range_stack = p;
6615 }
6616
6617 /* Within an array initializer, specify the next index to be initialized.
6618    FIRST is that index.  If LAST is nonzero, then initialize a range
6619    of indices, running from FIRST through LAST.  */
6620
6621 void
6622 set_init_index (tree first, tree last)
6623 {
6624   if (set_designator (1))
6625     return;
6626
6627   designator_erroneous = 1;
6628
6629   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
6630       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
6631     {
6632       error_init ("array index in initializer not of integer type");
6633       return;
6634     }
6635
6636   if (TREE_CODE (first) != INTEGER_CST)
6637     {
6638       first = c_fully_fold (first, false, NULL);
6639       if (TREE_CODE (first) == INTEGER_CST)
6640         pedwarn_init (input_location, OPT_pedantic,
6641                       "array index in initializer is not "
6642                       "an integer constant expression");
6643     }
6644
6645   if (last && TREE_CODE (last) != INTEGER_CST)
6646     {
6647       last = c_fully_fold (last, false, NULL);
6648       if (TREE_CODE (last) == INTEGER_CST)
6649         pedwarn_init (input_location, OPT_pedantic,
6650                       "array index in initializer is not "
6651                       "an integer constant expression");
6652     }
6653
6654   if (TREE_CODE (first) != INTEGER_CST)
6655     error_init ("nonconstant array index in initializer");
6656   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
6657     error_init ("nonconstant array index in initializer");
6658   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
6659     error_init ("array index in non-array initializer");
6660   else if (tree_int_cst_sgn (first) == -1)
6661     error_init ("array index in initializer exceeds array bounds");
6662   else if (constructor_max_index
6663            && tree_int_cst_lt (constructor_max_index, first))
6664     error_init ("array index in initializer exceeds array bounds");
6665   else
6666     {
6667       constant_expression_warning (first);
6668       if (last)
6669         constant_expression_warning (last);
6670       constructor_index = convert (bitsizetype, first);
6671
6672       if (last)
6673         {
6674           if (tree_int_cst_equal (first, last))
6675             last = 0;
6676           else if (tree_int_cst_lt (last, first))
6677             {
6678               error_init ("empty index range in initializer");
6679               last = 0;
6680             }
6681           else
6682             {
6683               last = convert (bitsizetype, last);
6684               if (constructor_max_index != 0
6685                   && tree_int_cst_lt (constructor_max_index, last))
6686                 {
6687                   error_init ("array index range in initializer exceeds array bounds");
6688                   last = 0;
6689                 }
6690             }
6691         }
6692
6693       designator_depth++;
6694       designator_erroneous = 0;
6695       if (constructor_range_stack || last)
6696         push_range_stack (last);
6697     }
6698 }
6699
6700 /* Within a struct initializer, specify the next field to be initialized.  */
6701
6702 void
6703 set_init_label (tree fieldname)
6704 {
6705   tree tail;
6706
6707   if (set_designator (0))
6708     return;
6709
6710   designator_erroneous = 1;
6711
6712   if (TREE_CODE (constructor_type) != RECORD_TYPE
6713       && TREE_CODE (constructor_type) != UNION_TYPE)
6714     {
6715       error_init ("field name not in record or union initializer");
6716       return;
6717     }
6718
6719   for (tail = TYPE_FIELDS (constructor_type); tail;
6720        tail = TREE_CHAIN (tail))
6721     {
6722       if (DECL_NAME (tail) == fieldname)
6723         break;
6724     }
6725
6726   if (tail == 0)
6727     error ("unknown field %qE specified in initializer", fieldname);
6728   else
6729     {
6730       constructor_fields = tail;
6731       designator_depth++;
6732       designator_erroneous = 0;
6733       if (constructor_range_stack)
6734         push_range_stack (NULL_TREE);
6735     }
6736 }
6737 \f
6738 /* Add a new initializer to the tree of pending initializers.  PURPOSE
6739    identifies the initializer, either array index or field in a structure.
6740    VALUE is the value of that index or field.  If ORIGTYPE is not
6741    NULL_TREE, it is the original type of VALUE.
6742
6743    IMPLICIT is true if value comes from pop_init_level (1),
6744    the new initializer has been merged with the existing one
6745    and thus no warnings should be emitted about overriding an
6746    existing initializer.  */
6747
6748 static void
6749 add_pending_init (tree purpose, tree value, tree origtype, bool implicit)
6750 {
6751   struct init_node *p, **q, *r;
6752
6753   q = &constructor_pending_elts;
6754   p = 0;
6755
6756   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6757     {
6758       while (*q != 0)
6759         {
6760           p = *q;
6761           if (tree_int_cst_lt (purpose, p->purpose))
6762             q = &p->left;
6763           else if (tree_int_cst_lt (p->purpose, purpose))
6764             q = &p->right;
6765           else
6766             {
6767               if (!implicit)
6768                 {
6769                   if (TREE_SIDE_EFFECTS (p->value))
6770                     warning_init (0, "initialized field with side-effects overwritten");
6771                   else if (warn_override_init)
6772                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6773                 }
6774               p->value = value;
6775               p->origtype = origtype;
6776               return;
6777             }
6778         }
6779     }
6780   else
6781     {
6782       tree bitpos;
6783
6784       bitpos = bit_position (purpose);
6785       while (*q != NULL)
6786         {
6787           p = *q;
6788           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6789             q = &p->left;
6790           else if (p->purpose != purpose)
6791             q = &p->right;
6792           else
6793             {
6794               if (!implicit)
6795                 {
6796                   if (TREE_SIDE_EFFECTS (p->value))
6797                     warning_init (0, "initialized field with side-effects overwritten");
6798                   else if (warn_override_init)
6799                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6800                 }
6801               p->value = value;
6802               p->origtype = origtype;
6803               return;
6804             }
6805         }
6806     }
6807
6808   r = GGC_NEW (struct init_node);
6809   r->purpose = purpose;
6810   r->value = value;
6811   r->origtype = origtype;
6812
6813   *q = r;
6814   r->parent = p;
6815   r->left = 0;
6816   r->right = 0;
6817   r->balance = 0;
6818
6819   while (p)
6820     {
6821       struct init_node *s;
6822
6823       if (r == p->left)
6824         {
6825           if (p->balance == 0)
6826             p->balance = -1;
6827           else if (p->balance < 0)
6828             {
6829               if (r->balance < 0)
6830                 {
6831                   /* L rotation.  */
6832                   p->left = r->right;
6833                   if (p->left)
6834                     p->left->parent = p;
6835                   r->right = p;
6836
6837                   p->balance = 0;
6838                   r->balance = 0;
6839
6840                   s = p->parent;
6841                   p->parent = r;
6842                   r->parent = s;
6843                   if (s)
6844                     {
6845                       if (s->left == p)
6846                         s->left = r;
6847                       else
6848                         s->right = r;
6849                     }
6850                   else
6851                     constructor_pending_elts = r;
6852                 }
6853               else
6854                 {
6855                   /* LR rotation.  */
6856                   struct init_node *t = r->right;
6857
6858                   r->right = t->left;
6859                   if (r->right)
6860                     r->right->parent = r;
6861                   t->left = r;
6862
6863                   p->left = t->right;
6864                   if (p->left)
6865                     p->left->parent = p;
6866                   t->right = p;
6867
6868                   p->balance = t->balance < 0;
6869                   r->balance = -(t->balance > 0);
6870                   t->balance = 0;
6871
6872                   s = p->parent;
6873                   p->parent = t;
6874                   r->parent = t;
6875                   t->parent = s;
6876                   if (s)
6877                     {
6878                       if (s->left == p)
6879                         s->left = t;
6880                       else
6881                         s->right = t;
6882                     }
6883                   else
6884                     constructor_pending_elts = t;
6885                 }
6886               break;
6887             }
6888           else
6889             {
6890               /* p->balance == +1; growth of left side balances the node.  */
6891               p->balance = 0;
6892               break;
6893             }
6894         }
6895       else /* r == p->right */
6896         {
6897           if (p->balance == 0)
6898             /* Growth propagation from right side.  */
6899             p->balance++;
6900           else if (p->balance > 0)
6901             {
6902               if (r->balance > 0)
6903                 {
6904                   /* R rotation.  */
6905                   p->right = r->left;
6906                   if (p->right)
6907                     p->right->parent = p;
6908                   r->left = p;
6909
6910                   p->balance = 0;
6911                   r->balance = 0;
6912
6913                   s = p->parent;
6914                   p->parent = r;
6915                   r->parent = s;
6916                   if (s)
6917                     {
6918                       if (s->left == p)
6919                         s->left = r;
6920                       else
6921                         s->right = r;
6922                     }
6923                   else
6924                     constructor_pending_elts = r;
6925                 }
6926               else /* r->balance == -1 */
6927                 {
6928                   /* RL rotation */
6929                   struct init_node *t = r->left;
6930
6931                   r->left = t->right;
6932                   if (r->left)
6933                     r->left->parent = r;
6934                   t->right = r;
6935
6936                   p->right = t->left;
6937                   if (p->right)
6938                     p->right->parent = p;
6939                   t->left = p;
6940
6941                   r->balance = (t->balance < 0);
6942                   p->balance = -(t->balance > 0);
6943                   t->balance = 0;
6944
6945                   s = p->parent;
6946                   p->parent = t;
6947                   r->parent = t;
6948                   t->parent = s;
6949                   if (s)
6950                     {
6951                       if (s->left == p)
6952                         s->left = t;
6953                       else
6954                         s->right = t;
6955                     }
6956                   else
6957                     constructor_pending_elts = t;
6958                 }
6959               break;
6960             }
6961           else
6962             {
6963               /* p->balance == -1; growth of right side balances the node.  */
6964               p->balance = 0;
6965               break;
6966             }
6967         }
6968
6969       r = p;
6970       p = p->parent;
6971     }
6972 }
6973
6974 /* Build AVL tree from a sorted chain.  */
6975
6976 static void
6977 set_nonincremental_init (void)
6978 {
6979   unsigned HOST_WIDE_INT ix;
6980   tree index, value;
6981
6982   if (TREE_CODE (constructor_type) != RECORD_TYPE
6983       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6984     return;
6985
6986   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6987     add_pending_init (index, value, NULL_TREE, false);
6988   constructor_elements = 0;
6989   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6990     {
6991       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6992       /* Skip any nameless bit fields at the beginning.  */
6993       while (constructor_unfilled_fields != 0
6994              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6995              && DECL_NAME (constructor_unfilled_fields) == 0)
6996         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6997
6998     }
6999   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7000     {
7001       if (TYPE_DOMAIN (constructor_type))
7002         constructor_unfilled_index
7003             = convert (bitsizetype,
7004                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
7005       else
7006         constructor_unfilled_index = bitsize_zero_node;
7007     }
7008   constructor_incremental = 0;
7009 }
7010
7011 /* Build AVL tree from a string constant.  */
7012
7013 static void
7014 set_nonincremental_init_from_string (tree str)
7015 {
7016   tree value, purpose, type;
7017   HOST_WIDE_INT val[2];
7018   const char *p, *end;
7019   int byte, wchar_bytes, charwidth, bitpos;
7020
7021   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
7022
7023   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
7024   charwidth = TYPE_PRECISION (char_type_node);
7025   type = TREE_TYPE (constructor_type);
7026   p = TREE_STRING_POINTER (str);
7027   end = p + TREE_STRING_LENGTH (str);
7028
7029   for (purpose = bitsize_zero_node;
7030        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
7031        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
7032     {
7033       if (wchar_bytes == 1)
7034         {
7035           val[1] = (unsigned char) *p++;
7036           val[0] = 0;
7037         }
7038       else
7039         {
7040           val[0] = 0;
7041           val[1] = 0;
7042           for (byte = 0; byte < wchar_bytes; byte++)
7043             {
7044               if (BYTES_BIG_ENDIAN)
7045                 bitpos = (wchar_bytes - byte - 1) * charwidth;
7046               else
7047                 bitpos = byte * charwidth;
7048               val[bitpos < HOST_BITS_PER_WIDE_INT]
7049                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
7050                    << (bitpos % HOST_BITS_PER_WIDE_INT);
7051             }
7052         }
7053
7054       if (!TYPE_UNSIGNED (type))
7055         {
7056           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
7057           if (bitpos < HOST_BITS_PER_WIDE_INT)
7058             {
7059               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
7060                 {
7061                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
7062                   val[0] = -1;
7063                 }
7064             }
7065           else if (bitpos == HOST_BITS_PER_WIDE_INT)
7066             {
7067               if (val[1] < 0)
7068                 val[0] = -1;
7069             }
7070           else if (val[0] & (((HOST_WIDE_INT) 1)
7071                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
7072             val[0] |= ((HOST_WIDE_INT) -1)
7073                       << (bitpos - HOST_BITS_PER_WIDE_INT);
7074         }
7075
7076       value = build_int_cst_wide (type, val[1], val[0]);
7077       add_pending_init (purpose, value, NULL_TREE, false);
7078     }
7079
7080   constructor_incremental = 0;
7081 }
7082
7083 /* Return value of FIELD in pending initializer or zero if the field was
7084    not initialized yet.  */
7085
7086 static tree
7087 find_init_member (tree field)
7088 {
7089   struct init_node *p;
7090
7091   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7092     {
7093       if (constructor_incremental
7094           && tree_int_cst_lt (field, constructor_unfilled_index))
7095         set_nonincremental_init ();
7096
7097       p = constructor_pending_elts;
7098       while (p)
7099         {
7100           if (tree_int_cst_lt (field, p->purpose))
7101             p = p->left;
7102           else if (tree_int_cst_lt (p->purpose, field))
7103             p = p->right;
7104           else
7105             return p->value;
7106         }
7107     }
7108   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7109     {
7110       tree bitpos = bit_position (field);
7111
7112       if (constructor_incremental
7113           && (!constructor_unfilled_fields
7114               || tree_int_cst_lt (bitpos,
7115                                   bit_position (constructor_unfilled_fields))))
7116         set_nonincremental_init ();
7117
7118       p = constructor_pending_elts;
7119       while (p)
7120         {
7121           if (field == p->purpose)
7122             return p->value;
7123           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7124             p = p->left;
7125           else
7126             p = p->right;
7127         }
7128     }
7129   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7130     {
7131       if (!VEC_empty (constructor_elt, constructor_elements)
7132           && (VEC_last (constructor_elt, constructor_elements)->index
7133               == field))
7134         return VEC_last (constructor_elt, constructor_elements)->value;
7135     }
7136   return 0;
7137 }
7138
7139 /* "Output" the next constructor element.
7140    At top level, really output it to assembler code now.
7141    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
7142    If ORIGTYPE is not NULL_TREE, it is the original type of VALUE.
7143    TYPE is the data type that the containing data type wants here.
7144    FIELD is the field (a FIELD_DECL) or the index that this element fills.
7145    If VALUE is a string constant, STRICT_STRING is true if it is
7146    unparenthesized or we should not warn here for it being parenthesized.
7147    For other types of VALUE, STRICT_STRING is not used.
7148
7149    PENDING if non-nil means output pending elements that belong
7150    right after this element.  (PENDING is normally 1;
7151    it is 0 while outputting pending elements, to avoid recursion.)
7152
7153    IMPLICIT is true if value comes from pop_init_level (1),
7154    the new initializer has been merged with the existing one
7155    and thus no warnings should be emitted about overriding an
7156    existing initializer.  */
7157
7158 static void
7159 output_init_element (tree value, tree origtype, bool strict_string, tree type,
7160                      tree field, int pending, bool implicit)
7161 {
7162   tree semantic_type = NULL_TREE;
7163   constructor_elt *celt;
7164   bool maybe_const = true;
7165   bool npc;
7166
7167   if (type == error_mark_node || value == error_mark_node)
7168     {
7169       constructor_erroneous = 1;
7170       return;
7171     }
7172   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
7173       && (TREE_CODE (value) == STRING_CST
7174           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
7175       && !(TREE_CODE (value) == STRING_CST
7176            && TREE_CODE (type) == ARRAY_TYPE
7177            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
7178       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
7179                      TYPE_MAIN_VARIANT (type)))
7180     value = array_to_pointer_conversion (input_location, value);
7181
7182   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
7183       && require_constant_value && !flag_isoc99 && pending)
7184     {
7185       /* As an extension, allow initializing objects with static storage
7186          duration with compound literals (which are then treated just as
7187          the brace enclosed list they contain).  */
7188       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
7189       value = DECL_INITIAL (decl);
7190     }
7191
7192   npc = null_pointer_constant_p (value);
7193   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
7194     {
7195       semantic_type = TREE_TYPE (value);
7196       value = TREE_OPERAND (value, 0);
7197     }
7198   value = c_fully_fold (value, require_constant_value, &maybe_const);
7199
7200   if (value == error_mark_node)
7201     constructor_erroneous = 1;
7202   else if (!TREE_CONSTANT (value))
7203     constructor_constant = 0;
7204   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
7205            || ((TREE_CODE (constructor_type) == RECORD_TYPE
7206                 || TREE_CODE (constructor_type) == UNION_TYPE)
7207                && DECL_C_BIT_FIELD (field)
7208                && TREE_CODE (value) != INTEGER_CST))
7209     constructor_simple = 0;
7210   if (!maybe_const)
7211     constructor_nonconst = 1;
7212
7213   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
7214     {
7215       if (require_constant_value)
7216         {
7217           error_init ("initializer element is not constant");
7218           value = error_mark_node;
7219         }
7220       else if (require_constant_elements)
7221         pedwarn (input_location, 0,
7222                  "initializer element is not computable at load time");
7223     }
7224   else if (!maybe_const
7225            && (require_constant_value || require_constant_elements))
7226     pedwarn_init (input_location, 0,
7227                   "initializer element is not a constant expression");
7228
7229   /* Issue -Wc++-compat warnings about initializing a bitfield with
7230      enum type.  */
7231   if (warn_cxx_compat
7232       && field != NULL_TREE
7233       && TREE_CODE (field) == FIELD_DECL
7234       && DECL_BIT_FIELD_TYPE (field) != NULL_TREE
7235       && (TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))
7236           != TYPE_MAIN_VARIANT (type))
7237       && TREE_CODE (DECL_BIT_FIELD_TYPE (field)) == ENUMERAL_TYPE)
7238     {
7239       tree checktype = origtype != NULL_TREE ? origtype : TREE_TYPE (value);
7240       if (checktype != error_mark_node
7241           && (TYPE_MAIN_VARIANT (checktype)
7242               != TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))))
7243         warning_init (OPT_Wc___compat,
7244                       "enum conversion in initialization is invalid in C++");
7245     }
7246
7247   /* If this field is empty (and not at the end of structure),
7248      don't do anything other than checking the initializer.  */
7249   if (field
7250       && (TREE_TYPE (field) == error_mark_node
7251           || (COMPLETE_TYPE_P (TREE_TYPE (field))
7252               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
7253               && (TREE_CODE (constructor_type) == ARRAY_TYPE
7254                   || TREE_CHAIN (field)))))
7255     return;
7256
7257   if (semantic_type)
7258     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
7259   value = digest_init (input_location, type, value, origtype, npc,
7260                        strict_string, require_constant_value);
7261   if (value == error_mark_node)
7262     {
7263       constructor_erroneous = 1;
7264       return;
7265     }
7266   if (require_constant_value || require_constant_elements)
7267     constant_expression_warning (value);
7268
7269   /* If this element doesn't come next in sequence,
7270      put it on constructor_pending_elts.  */
7271   if (TREE_CODE (constructor_type) == ARRAY_TYPE
7272       && (!constructor_incremental
7273           || !tree_int_cst_equal (field, constructor_unfilled_index)))
7274     {
7275       if (constructor_incremental
7276           && tree_int_cst_lt (field, constructor_unfilled_index))
7277         set_nonincremental_init ();
7278
7279       add_pending_init (field, value, origtype, implicit);
7280       return;
7281     }
7282   else if (TREE_CODE (constructor_type) == RECORD_TYPE
7283            && (!constructor_incremental
7284                || field != constructor_unfilled_fields))
7285     {
7286       /* We do this for records but not for unions.  In a union,
7287          no matter which field is specified, it can be initialized
7288          right away since it starts at the beginning of the union.  */
7289       if (constructor_incremental)
7290         {
7291           if (!constructor_unfilled_fields)
7292             set_nonincremental_init ();
7293           else
7294             {
7295               tree bitpos, unfillpos;
7296
7297               bitpos = bit_position (field);
7298               unfillpos = bit_position (constructor_unfilled_fields);
7299
7300               if (tree_int_cst_lt (bitpos, unfillpos))
7301                 set_nonincremental_init ();
7302             }
7303         }
7304
7305       add_pending_init (field, value, origtype, implicit);
7306       return;
7307     }
7308   else if (TREE_CODE (constructor_type) == UNION_TYPE
7309            && !VEC_empty (constructor_elt, constructor_elements))
7310     {
7311       if (!implicit)
7312         {
7313           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
7314                                            constructor_elements)->value))
7315             warning_init (0,
7316                           "initialized field with side-effects overwritten");
7317           else if (warn_override_init)
7318             warning_init (OPT_Woverride_init, "initialized field overwritten");
7319         }
7320
7321       /* We can have just one union field set.  */
7322       constructor_elements = 0;
7323     }
7324
7325   /* Otherwise, output this element either to
7326      constructor_elements or to the assembler file.  */
7327
7328   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
7329   celt->index = field;
7330   celt->value = value;
7331
7332   /* Advance the variable that indicates sequential elements output.  */
7333   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7334     constructor_unfilled_index
7335       = size_binop_loc (input_location, PLUS_EXPR, constructor_unfilled_index,
7336                         bitsize_one_node);
7337   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7338     {
7339       constructor_unfilled_fields
7340         = TREE_CHAIN (constructor_unfilled_fields);
7341
7342       /* Skip any nameless bit fields.  */
7343       while (constructor_unfilled_fields != 0
7344              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7345              && DECL_NAME (constructor_unfilled_fields) == 0)
7346         constructor_unfilled_fields =
7347           TREE_CHAIN (constructor_unfilled_fields);
7348     }
7349   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7350     constructor_unfilled_fields = 0;
7351
7352   /* Now output any pending elements which have become next.  */
7353   if (pending)
7354     output_pending_init_elements (0);
7355 }
7356
7357 /* Output any pending elements which have become next.
7358    As we output elements, constructor_unfilled_{fields,index}
7359    advances, which may cause other elements to become next;
7360    if so, they too are output.
7361
7362    If ALL is 0, we return when there are
7363    no more pending elements to output now.
7364
7365    If ALL is 1, we output space as necessary so that
7366    we can output all the pending elements.  */
7367
7368 static void
7369 output_pending_init_elements (int all)
7370 {
7371   struct init_node *elt = constructor_pending_elts;
7372   tree next;
7373
7374  retry:
7375
7376   /* Look through the whole pending tree.
7377      If we find an element that should be output now,
7378      output it.  Otherwise, set NEXT to the element
7379      that comes first among those still pending.  */
7380
7381   next = 0;
7382   while (elt)
7383     {
7384       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7385         {
7386           if (tree_int_cst_equal (elt->purpose,
7387                                   constructor_unfilled_index))
7388             output_init_element (elt->value, elt->origtype, true,
7389                                  TREE_TYPE (constructor_type),
7390                                  constructor_unfilled_index, 0, false);
7391           else if (tree_int_cst_lt (constructor_unfilled_index,
7392                                     elt->purpose))
7393             {
7394               /* Advance to the next smaller node.  */
7395               if (elt->left)
7396                 elt = elt->left;
7397               else
7398                 {
7399                   /* We have reached the smallest node bigger than the
7400                      current unfilled index.  Fill the space first.  */
7401                   next = elt->purpose;
7402                   break;
7403                 }
7404             }
7405           else
7406             {
7407               /* Advance to the next bigger node.  */
7408               if (elt->right)
7409                 elt = elt->right;
7410               else
7411                 {
7412                   /* We have reached the biggest node in a subtree.  Find
7413                      the parent of it, which is the next bigger node.  */
7414                   while (elt->parent && elt->parent->right == elt)
7415                     elt = elt->parent;
7416                   elt = elt->parent;
7417                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7418                                               elt->purpose))
7419                     {
7420                       next = elt->purpose;
7421                       break;
7422                     }
7423                 }
7424             }
7425         }
7426       else if (TREE_CODE (constructor_type) == RECORD_TYPE
7427                || TREE_CODE (constructor_type) == UNION_TYPE)
7428         {
7429           tree ctor_unfilled_bitpos, elt_bitpos;
7430
7431           /* If the current record is complete we are done.  */
7432           if (constructor_unfilled_fields == 0)
7433             break;
7434
7435           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
7436           elt_bitpos = bit_position (elt->purpose);
7437           /* We can't compare fields here because there might be empty
7438              fields in between.  */
7439           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
7440             {
7441               constructor_unfilled_fields = elt->purpose;
7442               output_init_element (elt->value, elt->origtype, true,
7443                                    TREE_TYPE (elt->purpose),
7444                                    elt->purpose, 0, false);
7445             }
7446           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
7447             {
7448               /* Advance to the next smaller node.  */
7449               if (elt->left)
7450                 elt = elt->left;
7451               else
7452                 {
7453                   /* We have reached the smallest node bigger than the
7454                      current unfilled field.  Fill the space first.  */
7455                   next = elt->purpose;
7456                   break;
7457                 }
7458             }
7459           else
7460             {
7461               /* Advance to the next bigger node.  */
7462               if (elt->right)
7463                 elt = elt->right;
7464               else
7465                 {
7466                   /* We have reached the biggest node in a subtree.  Find
7467                      the parent of it, which is the next bigger node.  */
7468                   while (elt->parent && elt->parent->right == elt)
7469                     elt = elt->parent;
7470                   elt = elt->parent;
7471                   if (elt
7472                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
7473                                            bit_position (elt->purpose))))
7474                     {
7475                       next = elt->purpose;
7476                       break;
7477                     }
7478                 }
7479             }
7480         }
7481     }
7482
7483   /* Ordinarily return, but not if we want to output all
7484      and there are elements left.  */
7485   if (!(all && next != 0))
7486     return;
7487
7488   /* If it's not incremental, just skip over the gap, so that after
7489      jumping to retry we will output the next successive element.  */
7490   if (TREE_CODE (constructor_type) == RECORD_TYPE
7491       || TREE_CODE (constructor_type) == UNION_TYPE)
7492     constructor_unfilled_fields = next;
7493   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7494     constructor_unfilled_index = next;
7495
7496   /* ELT now points to the node in the pending tree with the next
7497      initializer to output.  */
7498   goto retry;
7499 }
7500 \f
7501 /* Add one non-braced element to the current constructor level.
7502    This adjusts the current position within the constructor's type.
7503    This may also start or terminate implicit levels
7504    to handle a partly-braced initializer.
7505
7506    Once this has found the correct level for the new element,
7507    it calls output_init_element.
7508
7509    IMPLICIT is true if value comes from pop_init_level (1),
7510    the new initializer has been merged with the existing one
7511    and thus no warnings should be emitted about overriding an
7512    existing initializer.  */
7513
7514 void
7515 process_init_element (struct c_expr value, bool implicit)
7516 {
7517   tree orig_value = value.value;
7518   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
7519   bool strict_string = value.original_code == STRING_CST;
7520
7521   designator_depth = 0;
7522   designator_erroneous = 0;
7523
7524   /* Handle superfluous braces around string cst as in
7525      char x[] = {"foo"}; */
7526   if (string_flag
7527       && constructor_type
7528       && TREE_CODE (constructor_type) == ARRAY_TYPE
7529       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
7530       && integer_zerop (constructor_unfilled_index))
7531     {
7532       if (constructor_stack->replacement_value.value)
7533         error_init ("excess elements in char array initializer");
7534       constructor_stack->replacement_value = value;
7535       return;
7536     }
7537
7538   if (constructor_stack->replacement_value.value != 0)
7539     {
7540       error_init ("excess elements in struct initializer");
7541       return;
7542     }
7543
7544   /* Ignore elements of a brace group if it is entirely superfluous
7545      and has already been diagnosed.  */
7546   if (constructor_type == 0)
7547     return;
7548
7549   /* If we've exhausted any levels that didn't have braces,
7550      pop them now.  */
7551   while (constructor_stack->implicit)
7552     {
7553       if ((TREE_CODE (constructor_type) == RECORD_TYPE
7554            || TREE_CODE (constructor_type) == UNION_TYPE)
7555           && constructor_fields == 0)
7556         process_init_element (pop_init_level (1), true);
7557       else if ((TREE_CODE (constructor_type) == ARRAY_TYPE
7558                 || TREE_CODE (constructor_type) == VECTOR_TYPE)
7559                && (constructor_max_index == 0
7560                    || tree_int_cst_lt (constructor_max_index,
7561                                        constructor_index)))
7562         process_init_element (pop_init_level (1), true);
7563       else
7564         break;
7565     }
7566
7567   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
7568   if (constructor_range_stack)
7569     {
7570       /* If value is a compound literal and we'll be just using its
7571          content, don't put it into a SAVE_EXPR.  */
7572       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
7573           || !require_constant_value
7574           || flag_isoc99)
7575         {
7576           tree semantic_type = NULL_TREE;
7577           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
7578             {
7579               semantic_type = TREE_TYPE (value.value);
7580               value.value = TREE_OPERAND (value.value, 0);
7581             }
7582           value.value = c_save_expr (value.value);
7583           if (semantic_type)
7584             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
7585                                   value.value);
7586         }
7587     }
7588
7589   while (1)
7590     {
7591       if (TREE_CODE (constructor_type) == RECORD_TYPE)
7592         {
7593           tree fieldtype;
7594           enum tree_code fieldcode;
7595
7596           if (constructor_fields == 0)
7597             {
7598               pedwarn_init (input_location, 0,
7599                             "excess elements in struct initializer");
7600               break;
7601             }
7602
7603           fieldtype = TREE_TYPE (constructor_fields);
7604           if (fieldtype != error_mark_node)
7605             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7606           fieldcode = TREE_CODE (fieldtype);
7607
7608           /* Error for non-static initialization of a flexible array member.  */
7609           if (fieldcode == ARRAY_TYPE
7610               && !require_constant_value
7611               && TYPE_SIZE (fieldtype) == NULL_TREE
7612               && TREE_CHAIN (constructor_fields) == NULL_TREE)
7613             {
7614               error_init ("non-static initialization of a flexible array member");
7615               break;
7616             }
7617
7618           /* Accept a string constant to initialize a subarray.  */
7619           if (value.value != 0
7620               && fieldcode == ARRAY_TYPE
7621               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7622               && string_flag)
7623             value.value = orig_value;
7624           /* Otherwise, if we have come to a subaggregate,
7625              and we don't have an element of its type, push into it.  */
7626           else if (value.value != 0
7627                    && value.value != error_mark_node
7628                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7629                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7630                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7631             {
7632               push_init_level (1);
7633               continue;
7634             }
7635
7636           if (value.value)
7637             {
7638               push_member_name (constructor_fields);
7639               output_init_element (value.value, value.original_type,
7640                                    strict_string, fieldtype,
7641                                    constructor_fields, 1, implicit);
7642               RESTORE_SPELLING_DEPTH (constructor_depth);
7643             }
7644           else
7645             /* Do the bookkeeping for an element that was
7646                directly output as a constructor.  */
7647             {
7648               /* For a record, keep track of end position of last field.  */
7649               if (DECL_SIZE (constructor_fields))
7650                 constructor_bit_index
7651                   = size_binop_loc (input_location, PLUS_EXPR,
7652                                     bit_position (constructor_fields),
7653                                     DECL_SIZE (constructor_fields));
7654
7655               /* If the current field was the first one not yet written out,
7656                  it isn't now, so update.  */
7657               if (constructor_unfilled_fields == constructor_fields)
7658                 {
7659                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7660                   /* Skip any nameless bit fields.  */
7661                   while (constructor_unfilled_fields != 0
7662                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7663                          && DECL_NAME (constructor_unfilled_fields) == 0)
7664                     constructor_unfilled_fields =
7665                       TREE_CHAIN (constructor_unfilled_fields);
7666                 }
7667             }
7668
7669           constructor_fields = TREE_CHAIN (constructor_fields);
7670           /* Skip any nameless bit fields at the beginning.  */
7671           while (constructor_fields != 0
7672                  && DECL_C_BIT_FIELD (constructor_fields)
7673                  && DECL_NAME (constructor_fields) == 0)
7674             constructor_fields = TREE_CHAIN (constructor_fields);
7675         }
7676       else if (TREE_CODE (constructor_type) == UNION_TYPE)
7677         {
7678           tree fieldtype;
7679           enum tree_code fieldcode;
7680
7681           if (constructor_fields == 0)
7682             {
7683               pedwarn_init (input_location, 0,
7684                             "excess elements in union initializer");
7685               break;
7686             }
7687
7688           fieldtype = TREE_TYPE (constructor_fields);
7689           if (fieldtype != error_mark_node)
7690             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7691           fieldcode = TREE_CODE (fieldtype);
7692
7693           /* Warn that traditional C rejects initialization of unions.
7694              We skip the warning if the value is zero.  This is done
7695              under the assumption that the zero initializer in user
7696              code appears conditioned on e.g. __STDC__ to avoid
7697              "missing initializer" warnings and relies on default
7698              initialization to zero in the traditional C case.
7699              We also skip the warning if the initializer is designated,
7700              again on the assumption that this must be conditional on
7701              __STDC__ anyway (and we've already complained about the
7702              member-designator already).  */
7703           if (!in_system_header && !constructor_designated
7704               && !(value.value && (integer_zerop (value.value)
7705                                    || real_zerop (value.value))))
7706             warning (OPT_Wtraditional, "traditional C rejects initialization "
7707                      "of unions");
7708
7709           /* Accept a string constant to initialize a subarray.  */
7710           if (value.value != 0
7711               && fieldcode == ARRAY_TYPE
7712               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7713               && string_flag)
7714             value.value = orig_value;
7715           /* Otherwise, if we have come to a subaggregate,
7716              and we don't have an element of its type, push into it.  */
7717           else if (value.value != 0
7718                    && value.value != error_mark_node
7719                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7720                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7721                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7722             {
7723               push_init_level (1);
7724               continue;
7725             }
7726
7727           if (value.value)
7728             {
7729               push_member_name (constructor_fields);
7730               output_init_element (value.value, value.original_type,
7731                                    strict_string, fieldtype,
7732                                    constructor_fields, 1, implicit);
7733               RESTORE_SPELLING_DEPTH (constructor_depth);
7734             }
7735           else
7736             /* Do the bookkeeping for an element that was
7737                directly output as a constructor.  */
7738             {
7739               constructor_bit_index = DECL_SIZE (constructor_fields);
7740               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7741             }
7742
7743           constructor_fields = 0;
7744         }
7745       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7746         {
7747           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7748           enum tree_code eltcode = TREE_CODE (elttype);
7749
7750           /* Accept a string constant to initialize a subarray.  */
7751           if (value.value != 0
7752               && eltcode == ARRAY_TYPE
7753               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
7754               && string_flag)
7755             value.value = orig_value;
7756           /* Otherwise, if we have come to a subaggregate,
7757              and we don't have an element of its type, push into it.  */
7758           else if (value.value != 0
7759                    && value.value != error_mark_node
7760                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
7761                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
7762                        || eltcode == UNION_TYPE || eltcode == VECTOR_TYPE))
7763             {
7764               push_init_level (1);
7765               continue;
7766             }
7767
7768           if (constructor_max_index != 0
7769               && (tree_int_cst_lt (constructor_max_index, constructor_index)
7770                   || integer_all_onesp (constructor_max_index)))
7771             {
7772               pedwarn_init (input_location, 0,
7773                             "excess elements in array initializer");
7774               break;
7775             }
7776
7777           /* Now output the actual element.  */
7778           if (value.value)
7779             {
7780               push_array_bounds (tree_low_cst (constructor_index, 1));
7781               output_init_element (value.value, value.original_type,
7782                                    strict_string, elttype,
7783                                    constructor_index, 1, implicit);
7784               RESTORE_SPELLING_DEPTH (constructor_depth);
7785             }
7786
7787           constructor_index
7788             = size_binop_loc (input_location, PLUS_EXPR,
7789                               constructor_index, bitsize_one_node);
7790
7791           if (!value.value)
7792             /* If we are doing the bookkeeping for an element that was
7793                directly output as a constructor, we must update
7794                constructor_unfilled_index.  */
7795             constructor_unfilled_index = constructor_index;
7796         }
7797       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
7798         {
7799           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7800
7801          /* Do a basic check of initializer size.  Note that vectors
7802             always have a fixed size derived from their type.  */
7803           if (tree_int_cst_lt (constructor_max_index, constructor_index))
7804             {
7805               pedwarn_init (input_location, 0,
7806                             "excess elements in vector initializer");
7807               break;
7808             }
7809
7810           /* Now output the actual element.  */
7811           if (value.value)
7812             {
7813               if (TREE_CODE (value.value) == VECTOR_CST)
7814                 elttype = TYPE_MAIN_VARIANT (constructor_type);
7815               output_init_element (value.value, value.original_type,
7816                                    strict_string, elttype,
7817                                    constructor_index, 1, implicit);
7818             }
7819
7820           constructor_index
7821             = size_binop_loc (input_location,
7822                               PLUS_EXPR, constructor_index, bitsize_one_node);
7823
7824           if (!value.value)
7825             /* If we are doing the bookkeeping for an element that was
7826                directly output as a constructor, we must update
7827                constructor_unfilled_index.  */
7828             constructor_unfilled_index = constructor_index;
7829         }
7830
7831       /* Handle the sole element allowed in a braced initializer
7832          for a scalar variable.  */
7833       else if (constructor_type != error_mark_node
7834                && constructor_fields == 0)
7835         {
7836           pedwarn_init (input_location, 0,
7837                         "excess elements in scalar initializer");
7838           break;
7839         }
7840       else
7841         {
7842           if (value.value)
7843             output_init_element (value.value, value.original_type,
7844                                  strict_string, constructor_type,
7845                                  NULL_TREE, 1, implicit);
7846           constructor_fields = 0;
7847         }
7848
7849       /* Handle range initializers either at this level or anywhere higher
7850          in the designator stack.  */
7851       if (constructor_range_stack)
7852         {
7853           struct constructor_range_stack *p, *range_stack;
7854           int finish = 0;
7855
7856           range_stack = constructor_range_stack;
7857           constructor_range_stack = 0;
7858           while (constructor_stack != range_stack->stack)
7859             {
7860               gcc_assert (constructor_stack->implicit);
7861               process_init_element (pop_init_level (1), true);
7862             }
7863           for (p = range_stack;
7864                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
7865                p = p->prev)
7866             {
7867               gcc_assert (constructor_stack->implicit);
7868               process_init_element (pop_init_level (1), true);
7869             }
7870
7871           p->index = size_binop_loc (input_location,
7872                                      PLUS_EXPR, p->index, bitsize_one_node);
7873           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
7874             finish = 1;
7875
7876           while (1)
7877             {
7878               constructor_index = p->index;
7879               constructor_fields = p->fields;
7880               if (finish && p->range_end && p->index == p->range_start)
7881                 {
7882                   finish = 0;
7883                   p->prev = 0;
7884                 }
7885               p = p->next;
7886               if (!p)
7887                 break;
7888               push_init_level (2);
7889               p->stack = constructor_stack;
7890               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
7891                 p->index = p->range_start;
7892             }
7893
7894           if (!finish)
7895             constructor_range_stack = range_stack;
7896           continue;
7897         }
7898
7899       break;
7900     }
7901
7902   constructor_range_stack = 0;
7903 }
7904 \f
7905 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
7906    (guaranteed to be 'volatile' or null) and ARGS (represented using
7907    an ASM_EXPR node).  */
7908 tree
7909 build_asm_stmt (tree cv_qualifier, tree args)
7910 {
7911   if (!ASM_VOLATILE_P (args) && cv_qualifier)
7912     ASM_VOLATILE_P (args) = 1;
7913   return add_stmt (args);
7914 }
7915
7916 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
7917    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
7918    SIMPLE indicates whether there was anything at all after the
7919    string in the asm expression -- asm("blah") and asm("blah" : )
7920    are subtly different.  We use a ASM_EXPR node to represent this.  */
7921 tree
7922 build_asm_expr (location_t loc, tree string, tree outputs, tree inputs,
7923                 tree clobbers, bool simple)
7924 {
7925   tree tail;
7926   tree args;
7927   int i;
7928   const char *constraint;
7929   const char **oconstraints;
7930   bool allows_mem, allows_reg, is_inout;
7931   int ninputs, noutputs;
7932
7933   ninputs = list_length (inputs);
7934   noutputs = list_length (outputs);
7935   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
7936
7937   string = resolve_asm_operand_names (string, outputs, inputs);
7938
7939   /* Remove output conversions that change the type but not the mode.  */
7940   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
7941     {
7942       tree output = TREE_VALUE (tail);
7943
7944       /* ??? Really, this should not be here.  Users should be using a
7945          proper lvalue, dammit.  But there's a long history of using casts
7946          in the output operands.  In cases like longlong.h, this becomes a
7947          primitive form of typechecking -- if the cast can be removed, then
7948          the output operand had a type of the proper width; otherwise we'll
7949          get an error.  Gross, but ...  */
7950       STRIP_NOPS (output);
7951
7952       if (!lvalue_or_else (output, lv_asm))
7953         output = error_mark_node;
7954
7955       if (output != error_mark_node
7956           && (TREE_READONLY (output)
7957               || TYPE_READONLY (TREE_TYPE (output))
7958               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7959                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7960                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7961         readonly_error (output, lv_asm);
7962
7963       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7964       oconstraints[i] = constraint;
7965
7966       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7967                                    &allows_mem, &allows_reg, &is_inout))
7968         {
7969           /* If the operand is going to end up in memory,
7970              mark it addressable.  */
7971           if (!allows_reg && !c_mark_addressable (output))
7972             output = error_mark_node;
7973         }
7974       else
7975         output = error_mark_node;
7976
7977       TREE_VALUE (tail) = output;
7978     }
7979
7980   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7981     {
7982       tree input;
7983
7984       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7985       input = TREE_VALUE (tail);
7986
7987       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7988                                   oconstraints, &allows_mem, &allows_reg))
7989         {
7990           /* If the operand is going to end up in memory,
7991              mark it addressable.  */
7992           if (!allows_reg && allows_mem)
7993             {
7994               /* Strip the nops as we allow this case.  FIXME, this really
7995                  should be rejected or made deprecated.  */
7996               STRIP_NOPS (input);
7997               if (!c_mark_addressable (input))
7998                 input = error_mark_node;
7999           }
8000         }
8001       else
8002         input = error_mark_node;
8003
8004       TREE_VALUE (tail) = input;
8005     }
8006
8007   args = build_stmt (loc, ASM_EXPR, string, outputs, inputs, clobbers);
8008
8009   /* asm statements without outputs, including simple ones, are treated
8010      as volatile.  */
8011   ASM_INPUT_P (args) = simple;
8012   ASM_VOLATILE_P (args) = (noutputs == 0);
8013
8014   return args;
8015 }
8016 \f
8017 /* Generate a goto statement to LABEL.  LOC is the location of the
8018    GOTO.  */
8019
8020 tree
8021 c_finish_goto_label (location_t loc, tree label)
8022 {
8023   tree decl = lookup_label_for_goto (loc, label);
8024   if (!decl)
8025     return NULL_TREE;
8026   TREE_USED (decl) = 1;
8027   {
8028     tree t = build1 (GOTO_EXPR, void_type_node, decl);
8029     SET_EXPR_LOCATION (t, loc);
8030     return add_stmt (t);
8031   }
8032 }
8033
8034 /* Generate a computed goto statement to EXPR.  LOC is the location of
8035    the GOTO.  */
8036
8037 tree
8038 c_finish_goto_ptr (location_t loc, tree expr)
8039 {
8040   tree t;
8041   pedwarn (loc, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
8042   expr = c_fully_fold (expr, false, NULL);
8043   expr = convert (ptr_type_node, expr);
8044   t = build1 (GOTO_EXPR, void_type_node, expr);
8045   SET_EXPR_LOCATION (t, loc);
8046   return add_stmt (t);
8047 }
8048
8049 /* Generate a C `return' statement.  RETVAL is the expression for what
8050    to return, or a null pointer for `return;' with no value.  LOC is
8051    the location of the return statement.  If ORIGTYPE is not NULL_TREE, it
8052    is the original type of RETVAL.  */
8053
8054 tree
8055 c_finish_return (location_t loc, tree retval, tree origtype)
8056 {
8057   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
8058   bool no_warning = false;
8059   bool npc = false;
8060
8061   if (TREE_THIS_VOLATILE (current_function_decl))
8062     warning_at (loc, 0,
8063                 "function declared %<noreturn%> has a %<return%> statement");
8064
8065   if (retval)
8066     {
8067       tree semantic_type = NULL_TREE;
8068       npc = null_pointer_constant_p (retval);
8069       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
8070         {
8071           semantic_type = TREE_TYPE (retval);
8072           retval = TREE_OPERAND (retval, 0);
8073         }
8074       retval = c_fully_fold (retval, false, NULL);
8075       if (semantic_type)
8076         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
8077     }
8078
8079   if (!retval)
8080     {
8081       current_function_returns_null = 1;
8082       if ((warn_return_type || flag_isoc99)
8083           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
8084         {
8085           pedwarn_c99 (loc, flag_isoc99 ? 0 : OPT_Wreturn_type,
8086                        "%<return%> with no value, in "
8087                        "function returning non-void");
8088           no_warning = true;
8089         }
8090     }
8091   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
8092     {
8093       current_function_returns_null = 1;
8094       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
8095         pedwarn (loc, 0,
8096                  "%<return%> with a value, in function returning void");
8097       else
8098         pedwarn (loc, OPT_pedantic, "ISO C forbids "
8099                  "%<return%> with expression, in function returning void");
8100     }
8101   else
8102     {
8103       tree t = convert_for_assignment (loc, valtype, retval, origtype,
8104                                        ic_return,
8105                                        npc, NULL_TREE, NULL_TREE, 0);
8106       tree res = DECL_RESULT (current_function_decl);
8107       tree inner;
8108
8109       current_function_returns_value = 1;
8110       if (t == error_mark_node)
8111         return NULL_TREE;
8112
8113       inner = t = convert (TREE_TYPE (res), t);
8114
8115       /* Strip any conversions, additions, and subtractions, and see if
8116          we are returning the address of a local variable.  Warn if so.  */
8117       while (1)
8118         {
8119           switch (TREE_CODE (inner))
8120             {
8121             CASE_CONVERT:
8122             case NON_LVALUE_EXPR:
8123             case PLUS_EXPR:
8124             case POINTER_PLUS_EXPR:
8125               inner = TREE_OPERAND (inner, 0);
8126               continue;
8127
8128             case MINUS_EXPR:
8129               /* If the second operand of the MINUS_EXPR has a pointer
8130                  type (or is converted from it), this may be valid, so
8131                  don't give a warning.  */
8132               {
8133                 tree op1 = TREE_OPERAND (inner, 1);
8134
8135                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
8136                        && (CONVERT_EXPR_P (op1)
8137                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
8138                   op1 = TREE_OPERAND (op1, 0);
8139
8140                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
8141                   break;
8142
8143                 inner = TREE_OPERAND (inner, 0);
8144                 continue;
8145               }
8146
8147             case ADDR_EXPR:
8148               inner = TREE_OPERAND (inner, 0);
8149
8150               while (REFERENCE_CLASS_P (inner)
8151                      && TREE_CODE (inner) != INDIRECT_REF)
8152                 inner = TREE_OPERAND (inner, 0);
8153
8154               if (DECL_P (inner)
8155                   && !DECL_EXTERNAL (inner)
8156                   && !TREE_STATIC (inner)
8157                   && DECL_CONTEXT (inner) == current_function_decl)
8158                 warning_at (loc,
8159                             0, "function returns address of local variable");
8160               break;
8161
8162             default:
8163               break;
8164             }
8165
8166           break;
8167         }
8168
8169       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
8170       SET_EXPR_LOCATION (retval, loc);
8171
8172       if (warn_sequence_point)
8173         verify_sequence_points (retval);
8174     }
8175
8176   ret_stmt = build_stmt (loc, RETURN_EXPR, retval);
8177   TREE_NO_WARNING (ret_stmt) |= no_warning;
8178   return add_stmt (ret_stmt);
8179 }
8180 \f
8181 struct c_switch {
8182   /* The SWITCH_EXPR being built.  */
8183   tree switch_expr;
8184
8185   /* The original type of the testing expression, i.e. before the
8186      default conversion is applied.  */
8187   tree orig_type;
8188
8189   /* A splay-tree mapping the low element of a case range to the high
8190      element, or NULL_TREE if there is no high element.  Used to
8191      determine whether or not a new case label duplicates an old case
8192      label.  We need a tree, rather than simply a hash table, because
8193      of the GNU case range extension.  */
8194   splay_tree cases;
8195
8196   /* The bindings at the point of the switch.  This is used for
8197      warnings crossing decls when branching to a case label.  */
8198   struct c_spot_bindings *bindings;
8199
8200   /* The next node on the stack.  */
8201   struct c_switch *next;
8202 };
8203
8204 /* A stack of the currently active switch statements.  The innermost
8205    switch statement is on the top of the stack.  There is no need to
8206    mark the stack for garbage collection because it is only active
8207    during the processing of the body of a function, and we never
8208    collect at that point.  */
8209
8210 struct c_switch *c_switch_stack;
8211
8212 /* Start a C switch statement, testing expression EXP.  Return the new
8213    SWITCH_EXPR.  SWITCH_LOC is the location of the `switch'.
8214    SWITCH_COND_LOC is the location of the switch's condition.  */
8215
8216 tree
8217 c_start_case (location_t switch_loc,
8218               location_t switch_cond_loc,
8219               tree exp)
8220 {
8221   tree orig_type = error_mark_node;
8222   struct c_switch *cs;
8223
8224   if (exp != error_mark_node)
8225     {
8226       orig_type = TREE_TYPE (exp);
8227
8228       if (!INTEGRAL_TYPE_P (orig_type))
8229         {
8230           if (orig_type != error_mark_node)
8231             {
8232               error_at (switch_cond_loc, "switch quantity not an integer");
8233               orig_type = error_mark_node;
8234             }
8235           exp = integer_zero_node;
8236         }
8237       else
8238         {
8239           tree type = TYPE_MAIN_VARIANT (orig_type);
8240
8241           if (!in_system_header
8242               && (type == long_integer_type_node
8243                   || type == long_unsigned_type_node))
8244             warning_at (switch_cond_loc,
8245                         OPT_Wtraditional, "%<long%> switch expression not "
8246                         "converted to %<int%> in ISO C");
8247
8248           exp = c_fully_fold (exp, false, NULL);
8249           exp = default_conversion (exp);
8250
8251           if (warn_sequence_point)
8252             verify_sequence_points (exp);
8253         }
8254     }
8255
8256   /* Add this new SWITCH_EXPR to the stack.  */
8257   cs = XNEW (struct c_switch);
8258   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
8259   SET_EXPR_LOCATION (cs->switch_expr, switch_loc);
8260   cs->orig_type = orig_type;
8261   cs->cases = splay_tree_new (case_compare, NULL, NULL);
8262   cs->bindings = c_get_switch_bindings ();
8263   cs->next = c_switch_stack;
8264   c_switch_stack = cs;
8265
8266   return add_stmt (cs->switch_expr);
8267 }
8268
8269 /* Process a case label at location LOC.  */
8270
8271 tree
8272 do_case (location_t loc, tree low_value, tree high_value)
8273 {
8274   tree label = NULL_TREE;
8275
8276   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
8277     {
8278       low_value = c_fully_fold (low_value, false, NULL);
8279       if (TREE_CODE (low_value) == INTEGER_CST)
8280         pedwarn (input_location, OPT_pedantic,
8281                  "case label is not an integer constant expression");
8282     }
8283
8284   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
8285     {
8286       high_value = c_fully_fold (high_value, false, NULL);
8287       if (TREE_CODE (high_value) == INTEGER_CST)
8288         pedwarn (input_location, OPT_pedantic,
8289                  "case label is not an integer constant expression");
8290     }
8291
8292   if (c_switch_stack == NULL)
8293     {
8294       if (low_value)
8295         error_at (loc, "case label not within a switch statement");
8296       else
8297         error_at (loc, "%<default%> label not within a switch statement");
8298       return NULL_TREE;
8299     }
8300
8301   if (c_check_switch_jump_warnings (c_switch_stack->bindings,
8302                                     EXPR_LOCATION (c_switch_stack->switch_expr),
8303                                     loc))
8304     return NULL_TREE;
8305
8306   label = c_add_case_label (loc, c_switch_stack->cases,
8307                             SWITCH_COND (c_switch_stack->switch_expr),
8308                             c_switch_stack->orig_type,
8309                             low_value, high_value);
8310   if (label == error_mark_node)
8311     label = NULL_TREE;
8312   return label;
8313 }
8314
8315 /* Finish the switch statement.  */
8316
8317 void
8318 c_finish_case (tree body)
8319 {
8320   struct c_switch *cs = c_switch_stack;
8321   location_t switch_location;
8322
8323   SWITCH_BODY (cs->switch_expr) = body;
8324
8325   /* Emit warnings as needed.  */
8326   switch_location = EXPR_LOCATION (cs->switch_expr);
8327   c_do_switch_warnings (cs->cases, switch_location,
8328                         TREE_TYPE (cs->switch_expr),
8329                         SWITCH_COND (cs->switch_expr));
8330
8331   /* Pop the stack.  */
8332   c_switch_stack = cs->next;
8333   splay_tree_delete (cs->cases);
8334   c_release_switch_bindings (cs->bindings);
8335   XDELETE (cs);
8336 }
8337 \f
8338 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
8339    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
8340    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
8341    statement, and was not surrounded with parenthesis.  */
8342
8343 void
8344 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
8345                   tree else_block, bool nested_if)
8346 {
8347   tree stmt;
8348
8349   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
8350   if (warn_parentheses && nested_if && else_block == NULL)
8351     {
8352       tree inner_if = then_block;
8353
8354       /* We know from the grammar productions that there is an IF nested
8355          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
8356          it might not be exactly THEN_BLOCK, but should be the last
8357          non-container statement within.  */
8358       while (1)
8359         switch (TREE_CODE (inner_if))
8360           {
8361           case COND_EXPR:
8362             goto found;
8363           case BIND_EXPR:
8364             inner_if = BIND_EXPR_BODY (inner_if);
8365             break;
8366           case STATEMENT_LIST:
8367             inner_if = expr_last (then_block);
8368             break;
8369           case TRY_FINALLY_EXPR:
8370           case TRY_CATCH_EXPR:
8371             inner_if = TREE_OPERAND (inner_if, 0);
8372             break;
8373           default:
8374             gcc_unreachable ();
8375           }
8376     found:
8377
8378       if (COND_EXPR_ELSE (inner_if))
8379          warning_at (if_locus, OPT_Wparentheses,
8380                      "suggest explicit braces to avoid ambiguous %<else%>");
8381     }
8382
8383   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8384   SET_EXPR_LOCATION (stmt, if_locus);
8385   add_stmt (stmt);
8386 }
8387
8388 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8389    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8390    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8391    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8392    the continue label.  Everything is allowed to be NULL.  */
8393
8394 void
8395 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8396                tree blab, tree clab, bool cond_is_first)
8397 {
8398   tree entry = NULL, exit = NULL, t;
8399
8400   /* If the condition is zero don't generate a loop construct.  */
8401   if (cond && integer_zerop (cond))
8402     {
8403       if (cond_is_first)
8404         {
8405           t = build_and_jump (&blab);
8406           SET_EXPR_LOCATION (t, start_locus);
8407           add_stmt (t);
8408         }
8409     }
8410   else
8411     {
8412       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8413
8414       /* If we have an exit condition, then we build an IF with gotos either
8415          out of the loop, or to the top of it.  If there's no exit condition,
8416          then we just build a jump back to the top.  */
8417       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
8418
8419       if (cond && !integer_nonzerop (cond))
8420         {
8421           /* Canonicalize the loop condition to the end.  This means
8422              generating a branch to the loop condition.  Reuse the
8423              continue label, if possible.  */
8424           if (cond_is_first)
8425             {
8426               if (incr || !clab)
8427                 {
8428                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8429                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
8430                 }
8431               else
8432                 t = build1 (GOTO_EXPR, void_type_node, clab);
8433               SET_EXPR_LOCATION (t, start_locus);
8434               add_stmt (t);
8435             }
8436
8437           t = build_and_jump (&blab);
8438           if (cond_is_first)
8439             exit = fold_build3_loc (start_locus,
8440                                 COND_EXPR, void_type_node, cond, exit, t);
8441           else
8442             exit = fold_build3_loc (input_location,
8443                                 COND_EXPR, void_type_node, cond, exit, t);
8444         }
8445
8446       add_stmt (top);
8447     }
8448
8449   if (body)
8450     add_stmt (body);
8451   if (clab)
8452     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
8453   if (incr)
8454     add_stmt (incr);
8455   if (entry)
8456     add_stmt (entry);
8457   if (exit)
8458     add_stmt (exit);
8459   if (blab)
8460     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
8461 }
8462
8463 tree
8464 c_finish_bc_stmt (location_t loc, tree *label_p, bool is_break)
8465 {
8466   bool skip;
8467   tree label = *label_p;
8468
8469   /* In switch statements break is sometimes stylistically used after
8470      a return statement.  This can lead to spurious warnings about
8471      control reaching the end of a non-void function when it is
8472      inlined.  Note that we are calling block_may_fallthru with
8473      language specific tree nodes; this works because
8474      block_may_fallthru returns true when given something it does not
8475      understand.  */
8476   skip = !block_may_fallthru (cur_stmt_list);
8477
8478   if (!label)
8479     {
8480       if (!skip)
8481         *label_p = label = create_artificial_label (loc);
8482     }
8483   else if (TREE_CODE (label) == LABEL_DECL)
8484     ;
8485   else switch (TREE_INT_CST_LOW (label))
8486     {
8487     case 0:
8488       if (is_break)
8489         error_at (loc, "break statement not within loop or switch");
8490       else
8491         error_at (loc, "continue statement not within a loop");
8492       return NULL_TREE;
8493
8494     case 1:
8495       gcc_assert (is_break);
8496       error_at (loc, "break statement used with OpenMP for loop");
8497       return NULL_TREE;
8498
8499     default:
8500       gcc_unreachable ();
8501     }
8502
8503   if (skip)
8504     return NULL_TREE;
8505
8506   if (!is_break)
8507     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
8508
8509   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
8510 }
8511
8512 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
8513
8514 static void
8515 emit_side_effect_warnings (location_t loc, tree expr)
8516 {
8517   if (expr == error_mark_node)
8518     ;
8519   else if (!TREE_SIDE_EFFECTS (expr))
8520     {
8521       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
8522         warning_at (loc, OPT_Wunused_value, "statement with no effect");
8523     }
8524   else
8525     warn_if_unused_value (expr, loc);
8526 }
8527
8528 /* Process an expression as if it were a complete statement.  Emit
8529    diagnostics, but do not call ADD_STMT.  LOC is the location of the
8530    statement.  */
8531
8532 tree
8533 c_process_expr_stmt (location_t loc, tree expr)
8534 {
8535   if (!expr)
8536     return NULL_TREE;
8537
8538   expr = c_fully_fold (expr, false, NULL);
8539
8540   if (warn_sequence_point)
8541     verify_sequence_points (expr);
8542
8543   if (TREE_TYPE (expr) != error_mark_node
8544       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
8545       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
8546     error_at (loc, "expression statement has incomplete type");
8547
8548   /* If we're not processing a statement expression, warn about unused values.
8549      Warnings for statement expressions will be emitted later, once we figure
8550      out which is the result.  */
8551   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8552       && warn_unused_value)
8553     emit_side_effect_warnings (loc, expr);
8554
8555   /* If the expression is not of a type to which we cannot assign a line
8556      number, wrap the thing in a no-op NOP_EXPR.  */
8557   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
8558     {
8559       expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
8560       SET_EXPR_LOCATION (expr, loc);
8561     }
8562
8563   return expr;
8564 }
8565
8566 /* Emit an expression as a statement.  LOC is the location of the
8567    expression.  */
8568
8569 tree
8570 c_finish_expr_stmt (location_t loc, tree expr)
8571 {
8572   if (expr)
8573     return add_stmt (c_process_expr_stmt (loc, expr));
8574   else
8575     return NULL;
8576 }
8577
8578 /* Do the opposite and emit a statement as an expression.  To begin,
8579    create a new binding level and return it.  */
8580
8581 tree
8582 c_begin_stmt_expr (void)
8583 {
8584   tree ret;
8585
8586   /* We must force a BLOCK for this level so that, if it is not expanded
8587      later, there is a way to turn off the entire subtree of blocks that
8588      are contained in it.  */
8589   keep_next_level ();
8590   ret = c_begin_compound_stmt (true);
8591
8592   c_bindings_start_stmt_expr (c_switch_stack == NULL
8593                               ? NULL
8594                               : c_switch_stack->bindings);
8595
8596   /* Mark the current statement list as belonging to a statement list.  */
8597   STATEMENT_LIST_STMT_EXPR (ret) = 1;
8598
8599   return ret;
8600 }
8601
8602 /* LOC is the location of the compound statement to which this body
8603    belongs.  */
8604
8605 tree
8606 c_finish_stmt_expr (location_t loc, tree body)
8607 {
8608   tree last, type, tmp, val;
8609   tree *last_p;
8610
8611   body = c_end_compound_stmt (loc, body, true);
8612
8613   c_bindings_end_stmt_expr (c_switch_stack == NULL
8614                             ? NULL
8615                             : c_switch_stack->bindings);
8616
8617   /* Locate the last statement in BODY.  See c_end_compound_stmt
8618      about always returning a BIND_EXPR.  */
8619   last_p = &BIND_EXPR_BODY (body);
8620   last = BIND_EXPR_BODY (body);
8621
8622  continue_searching:
8623   if (TREE_CODE (last) == STATEMENT_LIST)
8624     {
8625       tree_stmt_iterator i;
8626
8627       /* This can happen with degenerate cases like ({ }).  No value.  */
8628       if (!TREE_SIDE_EFFECTS (last))
8629         return body;
8630
8631       /* If we're supposed to generate side effects warnings, process
8632          all of the statements except the last.  */
8633       if (warn_unused_value)
8634         {
8635           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
8636             {
8637               location_t tloc;
8638               tree t = tsi_stmt (i);
8639
8640               tloc = EXPR_HAS_LOCATION (t) ? EXPR_LOCATION (t) : loc;
8641               emit_side_effect_warnings (tloc, t);
8642             }
8643         }
8644       else
8645         i = tsi_last (last);
8646       last_p = tsi_stmt_ptr (i);
8647       last = *last_p;
8648     }
8649
8650   /* If the end of the list is exception related, then the list was split
8651      by a call to push_cleanup.  Continue searching.  */
8652   if (TREE_CODE (last) == TRY_FINALLY_EXPR
8653       || TREE_CODE (last) == TRY_CATCH_EXPR)
8654     {
8655       last_p = &TREE_OPERAND (last, 0);
8656       last = *last_p;
8657       goto continue_searching;
8658     }
8659
8660   /* In the case that the BIND_EXPR is not necessary, return the
8661      expression out from inside it.  */
8662   if (last == error_mark_node
8663       || (last == BIND_EXPR_BODY (body)
8664           && BIND_EXPR_VARS (body) == NULL))
8665     {
8666       /* Even if this looks constant, do not allow it in a constant
8667          expression.  */
8668       last = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (last), NULL_TREE, last);
8669       C_MAYBE_CONST_EXPR_NON_CONST (last) = 1;
8670       /* Do not warn if the return value of a statement expression is
8671          unused.  */
8672       TREE_NO_WARNING (last) = 1;
8673       return last;
8674     }
8675
8676   /* Extract the type of said expression.  */
8677   type = TREE_TYPE (last);
8678
8679   /* If we're not returning a value at all, then the BIND_EXPR that
8680      we already have is a fine expression to return.  */
8681   if (!type || VOID_TYPE_P (type))
8682     return body;
8683
8684   /* Now that we've located the expression containing the value, it seems
8685      silly to make voidify_wrapper_expr repeat the process.  Create a
8686      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
8687   tmp = create_tmp_var_raw (type, NULL);
8688
8689   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
8690      tree_expr_nonnegative_p giving up immediately.  */
8691   val = last;
8692   if (TREE_CODE (val) == NOP_EXPR
8693       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
8694     val = TREE_OPERAND (val, 0);
8695
8696   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
8697   SET_EXPR_LOCATION (*last_p, EXPR_LOCATION (last));
8698
8699   {
8700     tree t = build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
8701     SET_EXPR_LOCATION (t, loc);
8702     return t;
8703   }
8704 }
8705 \f
8706 /* Begin and end compound statements.  This is as simple as pushing
8707    and popping new statement lists from the tree.  */
8708
8709 tree
8710 c_begin_compound_stmt (bool do_scope)
8711 {
8712   tree stmt = push_stmt_list ();
8713   if (do_scope)
8714     push_scope ();
8715   return stmt;
8716 }
8717
8718 /* End a compound statement.  STMT is the statement.  LOC is the
8719    location of the compound statement-- this is usually the location
8720    of the opening brace.  */
8721
8722 tree
8723 c_end_compound_stmt (location_t loc, tree stmt, bool do_scope)
8724 {
8725   tree block = NULL;
8726
8727   if (do_scope)
8728     {
8729       if (c_dialect_objc ())
8730         objc_clear_super_receiver ();
8731       block = pop_scope ();
8732     }
8733
8734   stmt = pop_stmt_list (stmt);
8735   stmt = c_build_bind_expr (loc, block, stmt);
8736
8737   /* If this compound statement is nested immediately inside a statement
8738      expression, then force a BIND_EXPR to be created.  Otherwise we'll
8739      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
8740      STATEMENT_LISTs merge, and thus we can lose track of what statement
8741      was really last.  */
8742   if (cur_stmt_list
8743       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8744       && TREE_CODE (stmt) != BIND_EXPR)
8745     {
8746       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
8747       TREE_SIDE_EFFECTS (stmt) = 1;
8748       SET_EXPR_LOCATION (stmt, loc);
8749     }
8750
8751   return stmt;
8752 }
8753
8754 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
8755    when the current scope is exited.  EH_ONLY is true when this is not
8756    meant to apply to normal control flow transfer.  */
8757
8758 void
8759 push_cleanup (tree decl, tree cleanup, bool eh_only)
8760 {
8761   enum tree_code code;
8762   tree stmt, list;
8763   bool stmt_expr;
8764
8765   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
8766   stmt = build_stmt (DECL_SOURCE_LOCATION (decl), code, NULL, cleanup);
8767   add_stmt (stmt);
8768   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
8769   list = push_stmt_list ();
8770   TREE_OPERAND (stmt, 0) = list;
8771   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
8772 }
8773 \f
8774 /* Build a binary-operation expression without default conversions.
8775    CODE is the kind of expression to build.
8776    LOCATION is the operator's location.
8777    This function differs from `build' in several ways:
8778    the data type of the result is computed and recorded in it,
8779    warnings are generated if arg data types are invalid,
8780    special handling for addition and subtraction of pointers is known,
8781    and some optimization is done (operations on narrow ints
8782    are done in the narrower type when that gives the same result).
8783    Constant folding is also done before the result is returned.
8784
8785    Note that the operands will never have enumeral types, or function
8786    or array types, because either they will have the default conversions
8787    performed or they have both just been converted to some other type in which
8788    the arithmetic is to be done.  */
8789
8790 tree
8791 build_binary_op (location_t location, enum tree_code code,
8792                  tree orig_op0, tree orig_op1, int convert_p)
8793 {
8794   tree type0, type1, orig_type0, orig_type1;
8795   tree eptype;
8796   enum tree_code code0, code1;
8797   tree op0, op1;
8798   tree ret = error_mark_node;
8799   const char *invalid_op_diag;
8800   bool op0_int_operands, op1_int_operands;
8801   bool int_const, int_const_or_overflow, int_operands;
8802
8803   /* Expression code to give to the expression when it is built.
8804      Normally this is CODE, which is what the caller asked for,
8805      but in some special cases we change it.  */
8806   enum tree_code resultcode = code;
8807
8808   /* Data type in which the computation is to be performed.
8809      In the simplest cases this is the common type of the arguments.  */
8810   tree result_type = NULL;
8811
8812   /* When the computation is in excess precision, the type of the
8813      final EXCESS_PRECISION_EXPR.  */
8814   tree real_result_type = NULL;
8815
8816   /* Nonzero means operands have already been type-converted
8817      in whatever way is necessary.
8818      Zero means they need to be converted to RESULT_TYPE.  */
8819   int converted = 0;
8820
8821   /* Nonzero means create the expression with this type, rather than
8822      RESULT_TYPE.  */
8823   tree build_type = 0;
8824
8825   /* Nonzero means after finally constructing the expression
8826      convert it to this type.  */
8827   tree final_type = 0;
8828
8829   /* Nonzero if this is an operation like MIN or MAX which can
8830      safely be computed in short if both args are promoted shorts.
8831      Also implies COMMON.
8832      -1 indicates a bitwise operation; this makes a difference
8833      in the exact conditions for when it is safe to do the operation
8834      in a narrower mode.  */
8835   int shorten = 0;
8836
8837   /* Nonzero if this is a comparison operation;
8838      if both args are promoted shorts, compare the original shorts.
8839      Also implies COMMON.  */
8840   int short_compare = 0;
8841
8842   /* Nonzero if this is a right-shift operation, which can be computed on the
8843      original short and then promoted if the operand is a promoted short.  */
8844   int short_shift = 0;
8845
8846   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
8847   int common = 0;
8848
8849   /* True means types are compatible as far as ObjC is concerned.  */
8850   bool objc_ok;
8851
8852   /* True means this is an arithmetic operation that may need excess
8853      precision.  */
8854   bool may_need_excess_precision;
8855
8856   if (location == UNKNOWN_LOCATION)
8857     location = input_location;
8858
8859   op0 = orig_op0;
8860   op1 = orig_op1;
8861
8862   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
8863   if (op0_int_operands)
8864     op0 = remove_c_maybe_const_expr (op0);
8865   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
8866   if (op1_int_operands)
8867     op1 = remove_c_maybe_const_expr (op1);
8868   int_operands = (op0_int_operands && op1_int_operands);
8869   if (int_operands)
8870     {
8871       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
8872                                && TREE_CODE (orig_op1) == INTEGER_CST);
8873       int_const = (int_const_or_overflow
8874                    && !TREE_OVERFLOW (orig_op0)
8875                    && !TREE_OVERFLOW (orig_op1));
8876     }
8877   else
8878     int_const = int_const_or_overflow = false;
8879
8880   if (convert_p)
8881     {
8882       op0 = default_conversion (op0);
8883       op1 = default_conversion (op1);
8884     }
8885
8886   orig_type0 = type0 = TREE_TYPE (op0);
8887   orig_type1 = type1 = TREE_TYPE (op1);
8888
8889   /* The expression codes of the data types of the arguments tell us
8890      whether the arguments are integers, floating, pointers, etc.  */
8891   code0 = TREE_CODE (type0);
8892   code1 = TREE_CODE (type1);
8893
8894   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
8895   STRIP_TYPE_NOPS (op0);
8896   STRIP_TYPE_NOPS (op1);
8897
8898   /* If an error was already reported for one of the arguments,
8899      avoid reporting another error.  */
8900
8901   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8902     return error_mark_node;
8903
8904   if ((invalid_op_diag
8905        = targetm.invalid_binary_op (code, type0, type1)))
8906     {
8907       error_at (location, invalid_op_diag);
8908       return error_mark_node;
8909     }
8910
8911   switch (code)
8912     {
8913     case PLUS_EXPR:
8914     case MINUS_EXPR:
8915     case MULT_EXPR:
8916     case TRUNC_DIV_EXPR:
8917     case CEIL_DIV_EXPR:
8918     case FLOOR_DIV_EXPR:
8919     case ROUND_DIV_EXPR:
8920     case EXACT_DIV_EXPR:
8921       may_need_excess_precision = true;
8922       break;
8923     default:
8924       may_need_excess_precision = false;
8925       break;
8926     }
8927   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
8928     {
8929       op0 = TREE_OPERAND (op0, 0);
8930       type0 = TREE_TYPE (op0);
8931     }
8932   else if (may_need_excess_precision
8933            && (eptype = excess_precision_type (type0)) != NULL_TREE)
8934     {
8935       type0 = eptype;
8936       op0 = convert (eptype, op0);
8937     }
8938   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
8939     {
8940       op1 = TREE_OPERAND (op1, 0);
8941       type1 = TREE_TYPE (op1);
8942     }
8943   else if (may_need_excess_precision
8944            && (eptype = excess_precision_type (type1)) != NULL_TREE)
8945     {
8946       type1 = eptype;
8947       op1 = convert (eptype, op1);
8948     }
8949
8950   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8951
8952   switch (code)
8953     {
8954     case PLUS_EXPR:
8955       /* Handle the pointer + int case.  */
8956       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8957         {
8958           ret = pointer_int_sum (location, PLUS_EXPR, op0, op1);
8959           goto return_build_binary_op;
8960         }
8961       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8962         {
8963           ret = pointer_int_sum (location, PLUS_EXPR, op1, op0);
8964           goto return_build_binary_op;
8965         }
8966       else
8967         common = 1;
8968       break;
8969
8970     case MINUS_EXPR:
8971       /* Subtraction of two similar pointers.
8972          We must subtract them as integers, then divide by object size.  */
8973       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8974           && comp_target_types (location, type0, type1))
8975         {
8976           ret = pointer_diff (location, op0, op1);
8977           goto return_build_binary_op;
8978         }
8979       /* Handle pointer minus int.  Just like pointer plus int.  */
8980       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8981         {
8982           ret = pointer_int_sum (location, MINUS_EXPR, op0, op1);
8983           goto return_build_binary_op;
8984         }
8985       else
8986         common = 1;
8987       break;
8988
8989     case MULT_EXPR:
8990       common = 1;
8991       break;
8992
8993     case TRUNC_DIV_EXPR:
8994     case CEIL_DIV_EXPR:
8995     case FLOOR_DIV_EXPR:
8996     case ROUND_DIV_EXPR:
8997     case EXACT_DIV_EXPR:
8998       warn_for_div_by_zero (location, op1);
8999
9000       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9001            || code0 == FIXED_POINT_TYPE
9002            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9003           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9004               || code1 == FIXED_POINT_TYPE
9005               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
9006         {
9007           enum tree_code tcode0 = code0, tcode1 = code1;
9008
9009           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9010             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
9011           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
9012             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
9013
9014           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
9015               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
9016             resultcode = RDIV_EXPR;
9017           else
9018             /* Although it would be tempting to shorten always here, that
9019                loses on some targets, since the modulo instruction is
9020                undefined if the quotient can't be represented in the
9021                computation mode.  We shorten only if unsigned or if
9022                dividing by something we know != -1.  */
9023             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9024                        || (TREE_CODE (op1) == INTEGER_CST
9025                            && !integer_all_onesp (op1)));
9026           common = 1;
9027         }
9028       break;
9029
9030     case BIT_AND_EXPR:
9031     case BIT_IOR_EXPR:
9032     case BIT_XOR_EXPR:
9033       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9034         shorten = -1;
9035       /* Allow vector types which are not floating point types.   */
9036       else if (code0 == VECTOR_TYPE
9037                && code1 == VECTOR_TYPE
9038                && !VECTOR_FLOAT_TYPE_P (type0)
9039                && !VECTOR_FLOAT_TYPE_P (type1))
9040         common = 1;
9041       break;
9042
9043     case TRUNC_MOD_EXPR:
9044     case FLOOR_MOD_EXPR:
9045       warn_for_div_by_zero (location, op1);
9046
9047       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9048           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9049           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
9050         common = 1;
9051       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9052         {
9053           /* Although it would be tempting to shorten always here, that loses
9054              on some targets, since the modulo instruction is undefined if the
9055              quotient can't be represented in the computation mode.  We shorten
9056              only if unsigned or if dividing by something we know != -1.  */
9057           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9058                      || (TREE_CODE (op1) == INTEGER_CST
9059                          && !integer_all_onesp (op1)));
9060           common = 1;
9061         }
9062       break;
9063
9064     case TRUTH_ANDIF_EXPR:
9065     case TRUTH_ORIF_EXPR:
9066     case TRUTH_AND_EXPR:
9067     case TRUTH_OR_EXPR:
9068     case TRUTH_XOR_EXPR:
9069       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
9070            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9071            || code0 == FIXED_POINT_TYPE)
9072           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
9073               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9074               || code1 == FIXED_POINT_TYPE))
9075         {
9076           /* Result of these operations is always an int,
9077              but that does not mean the operands should be
9078              converted to ints!  */
9079           result_type = integer_type_node;
9080           op0 = c_common_truthvalue_conversion (location, op0);
9081           op1 = c_common_truthvalue_conversion (location, op1);
9082           converted = 1;
9083         }
9084       if (code == TRUTH_ANDIF_EXPR)
9085         {
9086           int_const_or_overflow = (int_operands
9087                                    && TREE_CODE (orig_op0) == INTEGER_CST
9088                                    && (op0 == truthvalue_false_node
9089                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9090           int_const = (int_const_or_overflow
9091                        && !TREE_OVERFLOW (orig_op0)
9092                        && (op0 == truthvalue_false_node
9093                            || !TREE_OVERFLOW (orig_op1)));
9094         }
9095       else if (code == TRUTH_ORIF_EXPR)
9096         {
9097           int_const_or_overflow = (int_operands
9098                                    && TREE_CODE (orig_op0) == INTEGER_CST
9099                                    && (op0 == truthvalue_true_node
9100                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9101           int_const = (int_const_or_overflow
9102                        && !TREE_OVERFLOW (orig_op0)
9103                        && (op0 == truthvalue_true_node
9104                            || !TREE_OVERFLOW (orig_op1)));
9105         }
9106       break;
9107
9108       /* Shift operations: result has same type as first operand;
9109          always convert second operand to int.
9110          Also set SHORT_SHIFT if shifting rightward.  */
9111
9112     case RSHIFT_EXPR:
9113       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9114           && code1 == INTEGER_TYPE)
9115         {
9116           if (TREE_CODE (op1) == INTEGER_CST)
9117             {
9118               if (tree_int_cst_sgn (op1) < 0)
9119                 {
9120                   int_const = false;
9121                   if (c_inhibit_evaluation_warnings == 0)
9122                     warning (0, "right shift count is negative");
9123                 }
9124               else
9125                 {
9126                   if (!integer_zerop (op1))
9127                     short_shift = 1;
9128
9129                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9130                     {
9131                       int_const = false;
9132                       if (c_inhibit_evaluation_warnings == 0)
9133                         warning (0, "right shift count >= width of type");
9134                     }
9135                 }
9136             }
9137
9138           /* Use the type of the value to be shifted.  */
9139           result_type = type0;
9140           /* Convert the shift-count to an integer, regardless of size
9141              of value being shifted.  */
9142           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9143             op1 = convert (integer_type_node, op1);
9144           /* Avoid converting op1 to result_type later.  */
9145           converted = 1;
9146         }
9147       break;
9148
9149     case LSHIFT_EXPR:
9150       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9151           && code1 == INTEGER_TYPE)
9152         {
9153           if (TREE_CODE (op1) == INTEGER_CST)
9154             {
9155               if (tree_int_cst_sgn (op1) < 0)
9156                 {
9157                   int_const = false;
9158                   if (c_inhibit_evaluation_warnings == 0)
9159                     warning (0, "left shift count is negative");
9160                 }
9161
9162               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9163                 {
9164                   int_const = false;
9165                   if (c_inhibit_evaluation_warnings == 0)
9166                     warning (0, "left shift count >= width of type");
9167                 }
9168             }
9169
9170           /* Use the type of the value to be shifted.  */
9171           result_type = type0;
9172           /* Convert the shift-count to an integer, regardless of size
9173              of value being shifted.  */
9174           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9175             op1 = convert (integer_type_node, op1);
9176           /* Avoid converting op1 to result_type later.  */
9177           converted = 1;
9178         }
9179       break;
9180
9181     case EQ_EXPR:
9182     case NE_EXPR:
9183       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
9184         warning_at (location,
9185                     OPT_Wfloat_equal,
9186                     "comparing floating point with == or != is unsafe");
9187       /* Result of comparison is always int,
9188          but don't convert the args to int!  */
9189       build_type = integer_type_node;
9190       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9191            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
9192           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9193               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
9194         short_compare = 1;
9195       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9196         {
9197           tree tt0 = TREE_TYPE (type0);
9198           tree tt1 = TREE_TYPE (type1);
9199           /* Anything compares with void *.  void * compares with anything.
9200              Otherwise, the targets must be compatible
9201              and both must be object or both incomplete.  */
9202           if (comp_target_types (location, type0, type1))
9203             result_type = common_pointer_type (type0, type1);
9204           else if (VOID_TYPE_P (tt0))
9205             {
9206               /* op0 != orig_op0 detects the case of something
9207                  whose value is 0 but which isn't a valid null ptr const.  */
9208               if (pedantic && !null_pointer_constant_p (orig_op0)
9209                   && TREE_CODE (tt1) == FUNCTION_TYPE)
9210                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9211                          "comparison of %<void *%> with function pointer");
9212             }
9213           else if (VOID_TYPE_P (tt1))
9214             {
9215               if (pedantic && !null_pointer_constant_p (orig_op1)
9216                   && TREE_CODE (tt0) == FUNCTION_TYPE)
9217                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9218                          "comparison of %<void *%> with function pointer");
9219             }
9220           else
9221             /* Avoid warning about the volatile ObjC EH puts on decls.  */
9222             if (!objc_ok)
9223               pedwarn (location, 0,
9224                        "comparison of distinct pointer types lacks a cast");
9225
9226           if (result_type == NULL_TREE)
9227             result_type = ptr_type_node;
9228         }
9229       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9230         {
9231           if (TREE_CODE (op0) == ADDR_EXPR
9232               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
9233             warning_at (location,
9234                         OPT_Waddress, "the address of %qD will never be NULL",
9235                         TREE_OPERAND (op0, 0));
9236           result_type = type0;
9237         }
9238       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9239         {
9240           if (TREE_CODE (op1) == ADDR_EXPR
9241               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
9242             warning_at (location,
9243                         OPT_Waddress, "the address of %qD will never be NULL",
9244                         TREE_OPERAND (op1, 0));
9245           result_type = type1;
9246         }
9247       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9248         {
9249           result_type = type0;
9250           pedwarn (location, 0, "comparison between pointer and integer");
9251         }
9252       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9253         {
9254           result_type = type1;
9255           pedwarn (location, 0, "comparison between pointer and integer");
9256         }
9257       break;
9258
9259     case LE_EXPR:
9260     case GE_EXPR:
9261     case LT_EXPR:
9262     case GT_EXPR:
9263       build_type = integer_type_node;
9264       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9265            || code0 == FIXED_POINT_TYPE)
9266           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9267               || code1 == FIXED_POINT_TYPE))
9268         short_compare = 1;
9269       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9270         {
9271           if (comp_target_types (location, type0, type1))
9272             {
9273               result_type = common_pointer_type (type0, type1);
9274               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
9275                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
9276                 pedwarn (location, 0,
9277                          "comparison of complete and incomplete pointers");
9278               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9279                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9280                          "ordered comparisons of pointers to functions");
9281             }
9282           else
9283             {
9284               result_type = ptr_type_node;
9285               pedwarn (location, 0,
9286                        "comparison of distinct pointer types lacks a cast");
9287             }
9288         }
9289       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9290         {
9291           result_type = type0;
9292           if (pedantic)
9293             pedwarn (location, OPT_pedantic,
9294                      "ordered comparison of pointer with integer zero");
9295           else if (extra_warnings)
9296             warning_at (location, OPT_Wextra,
9297                      "ordered comparison of pointer with integer zero");
9298         }
9299       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9300         {
9301           result_type = type1;
9302           pedwarn (location, OPT_pedantic,
9303                    "ordered comparison of pointer with integer zero");
9304         }
9305       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9306         {
9307           result_type = type0;
9308           pedwarn (location, 0, "comparison between pointer and integer");
9309         }
9310       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9311         {
9312           result_type = type1;
9313           pedwarn (location, 0, "comparison between pointer and integer");
9314         }
9315       break;
9316
9317     default:
9318       gcc_unreachable ();
9319     }
9320
9321   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9322     return error_mark_node;
9323
9324   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9325       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
9326           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
9327                                                     TREE_TYPE (type1))))
9328     {
9329       binary_op_error (location, code, type0, type1);
9330       return error_mark_node;
9331     }
9332
9333   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9334        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
9335       &&
9336       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9337        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
9338     {
9339       bool first_complex = (code0 == COMPLEX_TYPE);
9340       bool second_complex = (code1 == COMPLEX_TYPE);
9341       int none_complex = (!first_complex && !second_complex);
9342
9343       if (shorten || common || short_compare)
9344         {
9345           result_type = c_common_type (type0, type1);
9346           if (result_type == error_mark_node)
9347             return error_mark_node;
9348         }
9349
9350       if (first_complex != second_complex
9351           && (code == PLUS_EXPR
9352               || code == MINUS_EXPR
9353               || code == MULT_EXPR
9354               || (code == TRUNC_DIV_EXPR && first_complex))
9355           && TREE_CODE (TREE_TYPE (result_type)) == REAL_TYPE
9356           && flag_signed_zeros)
9357         {
9358           /* An operation on mixed real/complex operands must be
9359              handled specially, but the language-independent code can
9360              more easily optimize the plain complex arithmetic if
9361              -fno-signed-zeros.  */
9362           tree real_type = TREE_TYPE (result_type);
9363           tree real, imag;
9364           if (type0 != orig_type0 || type1 != orig_type1)
9365             {
9366               gcc_assert (may_need_excess_precision && common);
9367               real_result_type = c_common_type (orig_type0, orig_type1);
9368             }
9369           if (first_complex)
9370             {
9371               if (TREE_TYPE (op0) != result_type)
9372                 op0 = convert_and_check (result_type, op0);
9373               if (TREE_TYPE (op1) != real_type)
9374                 op1 = convert_and_check (real_type, op1);
9375             }
9376           else
9377             {
9378               if (TREE_TYPE (op0) != real_type)
9379                 op0 = convert_and_check (real_type, op0);
9380               if (TREE_TYPE (op1) != result_type)
9381                 op1 = convert_and_check (result_type, op1);
9382             }
9383           if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9384             return error_mark_node;
9385           if (first_complex)
9386             {
9387               op0 = c_save_expr (op0);
9388               real = build_unary_op (EXPR_LOCATION (orig_op0), REALPART_EXPR,
9389                                      op0, 1);
9390               imag = build_unary_op (EXPR_LOCATION (orig_op0), IMAGPART_EXPR,
9391                                      op0, 1);
9392               switch (code)
9393                 {
9394                 case MULT_EXPR:
9395                 case TRUNC_DIV_EXPR:
9396                   imag = build2 (resultcode, real_type, imag, op1);
9397                   /* Fall through.  */
9398                 case PLUS_EXPR:
9399                 case MINUS_EXPR:
9400                   real = build2 (resultcode, real_type, real, op1);
9401                   break;
9402                 default:
9403                   gcc_unreachable();
9404                 }
9405             }
9406           else
9407             {
9408               op1 = c_save_expr (op1);
9409               real = build_unary_op (EXPR_LOCATION (orig_op1), REALPART_EXPR,
9410                                      op1, 1);
9411               imag = build_unary_op (EXPR_LOCATION (orig_op1), IMAGPART_EXPR,
9412                                      op1, 1);
9413               switch (code)
9414                 {
9415                 case MULT_EXPR:
9416                   imag = build2 (resultcode, real_type, op0, imag);
9417                   /* Fall through.  */
9418                 case PLUS_EXPR:
9419                   real = build2 (resultcode, real_type, op0, real);
9420                   break;
9421                 case MINUS_EXPR:
9422                   real = build2 (resultcode, real_type, op0, real);
9423                   imag = build1 (NEGATE_EXPR, real_type, imag);
9424                   break;
9425                 default:
9426                   gcc_unreachable();
9427                 }
9428             }
9429           ret = build2 (COMPLEX_EXPR, result_type, real, imag);
9430           goto return_build_binary_op;
9431         }
9432
9433       /* For certain operations (which identify themselves by shorten != 0)
9434          if both args were extended from the same smaller type,
9435          do the arithmetic in that type and then extend.
9436
9437          shorten !=0 and !=1 indicates a bitwise operation.
9438          For them, this optimization is safe only if
9439          both args are zero-extended or both are sign-extended.
9440          Otherwise, we might change the result.
9441          Eg, (short)-1 | (unsigned short)-1 is (int)-1
9442          but calculated in (unsigned short) it would be (unsigned short)-1.  */
9443
9444       if (shorten && none_complex)
9445         {
9446           final_type = result_type;
9447           result_type = shorten_binary_op (result_type, op0, op1,
9448                                            shorten == -1);
9449         }
9450
9451       /* Shifts can be shortened if shifting right.  */
9452
9453       if (short_shift)
9454         {
9455           int unsigned_arg;
9456           tree arg0 = get_narrower (op0, &unsigned_arg);
9457
9458           final_type = result_type;
9459
9460           if (arg0 == op0 && final_type == TREE_TYPE (op0))
9461             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
9462
9463           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
9464               /* We can shorten only if the shift count is less than the
9465                  number of bits in the smaller type size.  */
9466               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
9467               /* We cannot drop an unsigned shift after sign-extension.  */
9468               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
9469             {
9470               /* Do an unsigned shift if the operand was zero-extended.  */
9471               result_type
9472                 = c_common_signed_or_unsigned_type (unsigned_arg,
9473                                                     TREE_TYPE (arg0));
9474               /* Convert value-to-be-shifted to that type.  */
9475               if (TREE_TYPE (op0) != result_type)
9476                 op0 = convert (result_type, op0);
9477               converted = 1;
9478             }
9479         }
9480
9481       /* Comparison operations are shortened too but differently.
9482          They identify themselves by setting short_compare = 1.  */
9483
9484       if (short_compare)
9485         {
9486           /* Don't write &op0, etc., because that would prevent op0
9487              from being kept in a register.
9488              Instead, make copies of the our local variables and
9489              pass the copies by reference, then copy them back afterward.  */
9490           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
9491           enum tree_code xresultcode = resultcode;
9492           tree val
9493             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
9494
9495           if (val != 0)
9496             {
9497               ret = val;
9498               goto return_build_binary_op;
9499             }
9500
9501           op0 = xop0, op1 = xop1;
9502           converted = 1;
9503           resultcode = xresultcode;
9504
9505           if (c_inhibit_evaluation_warnings == 0)
9506             {
9507               bool op0_maybe_const = true;
9508               bool op1_maybe_const = true;
9509               tree orig_op0_folded, orig_op1_folded;
9510
9511               if (in_late_binary_op)
9512                 {
9513                   orig_op0_folded = orig_op0;
9514                   orig_op1_folded = orig_op1;
9515                 }
9516               else
9517                 {
9518                   /* Fold for the sake of possible warnings, as in
9519                      build_conditional_expr.  This requires the
9520                      "original" values to be folded, not just op0 and
9521                      op1.  */
9522                   c_inhibit_evaluation_warnings++;
9523                   op0 = c_fully_fold (op0, require_constant_value,
9524                                       &op0_maybe_const);
9525                   op1 = c_fully_fold (op1, require_constant_value,
9526                                       &op1_maybe_const);
9527                   c_inhibit_evaluation_warnings--;
9528                   orig_op0_folded = c_fully_fold (orig_op0,
9529                                                   require_constant_value,
9530                                                   NULL);
9531                   orig_op1_folded = c_fully_fold (orig_op1,
9532                                                   require_constant_value,
9533                                                   NULL);
9534                 }
9535
9536               if (warn_sign_compare)
9537                 warn_for_sign_compare (location, orig_op0_folded,
9538                                        orig_op1_folded, op0, op1,
9539                                        result_type, resultcode);
9540               if (!in_late_binary_op)
9541                 {
9542                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
9543                     {
9544                       op0 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op0),
9545                                     NULL, op0);
9546                       C_MAYBE_CONST_EXPR_NON_CONST (op0) = !op0_maybe_const;
9547                     }
9548                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
9549                     {
9550                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
9551                                     NULL, op1);
9552                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
9553                     }
9554                 }
9555             }
9556         }
9557     }
9558
9559   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
9560      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
9561      Then the expression will be built.
9562      It will be given type FINAL_TYPE if that is nonzero;
9563      otherwise, it will be given type RESULT_TYPE.  */
9564
9565   if (!result_type)
9566     {
9567       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
9568       return error_mark_node;
9569     }
9570
9571   if (!converted)
9572     {
9573       if (TREE_TYPE (op0) != result_type)
9574         op0 = convert_and_check (result_type, op0);
9575       if (TREE_TYPE (op1) != result_type)
9576         op1 = convert_and_check (result_type, op1);
9577
9578       /* This can happen if one operand has a vector type, and the other
9579          has a different type.  */
9580       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9581         return error_mark_node;
9582     }
9583
9584   if (build_type == NULL_TREE)
9585     {
9586       build_type = result_type;
9587       if (type0 != orig_type0 || type1 != orig_type1)
9588         {
9589           gcc_assert (may_need_excess_precision && common);
9590           real_result_type = c_common_type (orig_type0, orig_type1);
9591         }
9592     }
9593
9594   /* Treat expressions in initializers specially as they can't trap.  */
9595   if (int_const_or_overflow)
9596     ret = (require_constant_value
9597            ? fold_build2_initializer_loc (location, resultcode, build_type,
9598                                           op0, op1)
9599            : fold_build2_loc (location, resultcode, build_type, op0, op1));
9600   else
9601     ret = build2 (resultcode, build_type, op0, op1);
9602   if (final_type != 0)
9603     ret = convert (final_type, ret);
9604
9605  return_build_binary_op:
9606   gcc_assert (ret != error_mark_node);
9607   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
9608     ret = (int_operands
9609            ? note_integer_operands (ret)
9610            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
9611   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
9612            && !in_late_binary_op)
9613     ret = note_integer_operands (ret);
9614   if (real_result_type)
9615     ret = build1 (EXCESS_PRECISION_EXPR, real_result_type, ret);
9616   protected_set_expr_location (ret, location);
9617   return ret;
9618 }
9619
9620
9621 /* Convert EXPR to be a truth-value, validating its type for this
9622    purpose.  LOCATION is the source location for the expression.  */
9623
9624 tree
9625 c_objc_common_truthvalue_conversion (location_t location, tree expr)
9626 {
9627   bool int_const, int_operands;
9628
9629   switch (TREE_CODE (TREE_TYPE (expr)))
9630     {
9631     case ARRAY_TYPE:
9632       error_at (location, "used array that cannot be converted to pointer where scalar is required");
9633       return error_mark_node;
9634
9635     case RECORD_TYPE:
9636       error_at (location, "used struct type value where scalar is required");
9637       return error_mark_node;
9638
9639     case UNION_TYPE:
9640       error_at (location, "used union type value where scalar is required");
9641       return error_mark_node;
9642
9643     case FUNCTION_TYPE:
9644       gcc_unreachable ();
9645
9646     default:
9647       break;
9648     }
9649
9650   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
9651   int_operands = EXPR_INT_CONST_OPERANDS (expr);
9652   if (int_operands)
9653     expr = remove_c_maybe_const_expr (expr);
9654
9655   /* ??? Should we also give an error for void and vectors rather than
9656      leaving those to give errors later?  */
9657   expr = c_common_truthvalue_conversion (location, expr);
9658
9659   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
9660     {
9661       if (TREE_OVERFLOW (expr))
9662         return expr;
9663       else
9664         return note_integer_operands (expr);
9665     }
9666   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
9667     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9668   return expr;
9669 }
9670 \f
9671
9672 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
9673    required.  */
9674
9675 tree
9676 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
9677 {
9678   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
9679     {
9680       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
9681       /* Executing a compound literal inside a function reinitializes
9682          it.  */
9683       if (!TREE_STATIC (decl))
9684         *se = true;
9685       return decl;
9686     }
9687   else
9688     return expr;
9689 }
9690 \f
9691 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9692
9693 tree
9694 c_begin_omp_parallel (void)
9695 {
9696   tree block;
9697
9698   keep_next_level ();
9699   block = c_begin_compound_stmt (true);
9700
9701   return block;
9702 }
9703
9704 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound
9705    statement.  LOC is the location of the OMP_PARALLEL.  */
9706
9707 tree
9708 c_finish_omp_parallel (location_t loc, tree clauses, tree block)
9709 {
9710   tree stmt;
9711
9712   block = c_end_compound_stmt (loc, block, true);
9713
9714   stmt = make_node (OMP_PARALLEL);
9715   TREE_TYPE (stmt) = void_type_node;
9716   OMP_PARALLEL_CLAUSES (stmt) = clauses;
9717   OMP_PARALLEL_BODY (stmt) = block;
9718   SET_EXPR_LOCATION (stmt, loc);
9719
9720   return add_stmt (stmt);
9721 }
9722
9723 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9724
9725 tree
9726 c_begin_omp_task (void)
9727 {
9728   tree block;
9729
9730   keep_next_level ();
9731   block = c_begin_compound_stmt (true);
9732
9733   return block;
9734 }
9735
9736 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound
9737    statement.  LOC is the location of the #pragma.  */
9738
9739 tree
9740 c_finish_omp_task (location_t loc, tree clauses, tree block)
9741 {
9742   tree stmt;
9743
9744   block = c_end_compound_stmt (loc, block, true);
9745
9746   stmt = make_node (OMP_TASK);
9747   TREE_TYPE (stmt) = void_type_node;
9748   OMP_TASK_CLAUSES (stmt) = clauses;
9749   OMP_TASK_BODY (stmt) = block;
9750   SET_EXPR_LOCATION (stmt, loc);
9751
9752   return add_stmt (stmt);
9753 }
9754
9755 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
9756    Remove any elements from the list that are invalid.  */
9757
9758 tree
9759 c_finish_omp_clauses (tree clauses)
9760 {
9761   bitmap_head generic_head, firstprivate_head, lastprivate_head;
9762   tree c, t, *pc = &clauses;
9763   const char *name;
9764
9765   bitmap_obstack_initialize (NULL);
9766   bitmap_initialize (&generic_head, &bitmap_default_obstack);
9767   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
9768   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
9769
9770   for (pc = &clauses, c = clauses; c ; c = *pc)
9771     {
9772       bool remove = false;
9773       bool need_complete = false;
9774       bool need_implicitly_determined = false;
9775
9776       switch (OMP_CLAUSE_CODE (c))
9777         {
9778         case OMP_CLAUSE_SHARED:
9779           name = "shared";
9780           need_implicitly_determined = true;
9781           goto check_dup_generic;
9782
9783         case OMP_CLAUSE_PRIVATE:
9784           name = "private";
9785           need_complete = true;
9786           need_implicitly_determined = true;
9787           goto check_dup_generic;
9788
9789         case OMP_CLAUSE_REDUCTION:
9790           name = "reduction";
9791           need_implicitly_determined = true;
9792           t = OMP_CLAUSE_DECL (c);
9793           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
9794               || POINTER_TYPE_P (TREE_TYPE (t)))
9795             {
9796               error_at (OMP_CLAUSE_LOCATION (c),
9797                         "%qE has invalid type for %<reduction%>", t);
9798               remove = true;
9799             }
9800           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
9801             {
9802               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
9803               const char *r_name = NULL;
9804
9805               switch (r_code)
9806                 {
9807                 case PLUS_EXPR:
9808                 case MULT_EXPR:
9809                 case MINUS_EXPR:
9810                   break;
9811                 case BIT_AND_EXPR:
9812                   r_name = "&";
9813                   break;
9814                 case BIT_XOR_EXPR:
9815                   r_name = "^";
9816                   break;
9817                 case BIT_IOR_EXPR:
9818                   r_name = "|";
9819                   break;
9820                 case TRUTH_ANDIF_EXPR:
9821                   r_name = "&&";
9822                   break;
9823                 case TRUTH_ORIF_EXPR:
9824                   r_name = "||";
9825                   break;
9826                 default:
9827                   gcc_unreachable ();
9828                 }
9829               if (r_name)
9830                 {
9831                   error_at (OMP_CLAUSE_LOCATION (c),
9832                             "%qE has invalid type for %<reduction(%s)%>",
9833                             t, r_name);
9834                   remove = true;
9835                 }
9836             }
9837           goto check_dup_generic;
9838
9839         case OMP_CLAUSE_COPYPRIVATE:
9840           name = "copyprivate";
9841           goto check_dup_generic;
9842
9843         case OMP_CLAUSE_COPYIN:
9844           name = "copyin";
9845           t = OMP_CLAUSE_DECL (c);
9846           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
9847             {
9848               error_at (OMP_CLAUSE_LOCATION (c),
9849                         "%qE must be %<threadprivate%> for %<copyin%>", t);
9850               remove = true;
9851             }
9852           goto check_dup_generic;
9853
9854         check_dup_generic:
9855           t = OMP_CLAUSE_DECL (c);
9856           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9857             {
9858               error_at (OMP_CLAUSE_LOCATION (c),
9859                         "%qE is not a variable in clause %qs", t, name);
9860               remove = true;
9861             }
9862           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9863                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
9864                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9865             {
9866               error_at (OMP_CLAUSE_LOCATION (c),
9867                         "%qE appears more than once in data clauses", t);
9868               remove = true;
9869             }
9870           else
9871             bitmap_set_bit (&generic_head, DECL_UID (t));
9872           break;
9873
9874         case OMP_CLAUSE_FIRSTPRIVATE:
9875           name = "firstprivate";
9876           t = OMP_CLAUSE_DECL (c);
9877           need_complete = true;
9878           need_implicitly_determined = true;
9879           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9880             {
9881               error_at (OMP_CLAUSE_LOCATION (c),
9882                         "%qE is not a variable in clause %<firstprivate%>", t);
9883               remove = true;
9884             }
9885           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9886                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
9887             {
9888               error_at (OMP_CLAUSE_LOCATION (c),
9889                         "%qE appears more than once in data clauses", t);
9890               remove = true;
9891             }
9892           else
9893             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
9894           break;
9895
9896         case OMP_CLAUSE_LASTPRIVATE:
9897           name = "lastprivate";
9898           t = OMP_CLAUSE_DECL (c);
9899           need_complete = true;
9900           need_implicitly_determined = true;
9901           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9902             {
9903               error_at (OMP_CLAUSE_LOCATION (c),
9904                         "%qE is not a variable in clause %<lastprivate%>", t);
9905               remove = true;
9906             }
9907           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9908                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9909             {
9910               error_at (OMP_CLAUSE_LOCATION (c),
9911                      "%qE appears more than once in data clauses", t);
9912               remove = true;
9913             }
9914           else
9915             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
9916           break;
9917
9918         case OMP_CLAUSE_IF:
9919         case OMP_CLAUSE_NUM_THREADS:
9920         case OMP_CLAUSE_SCHEDULE:
9921         case OMP_CLAUSE_NOWAIT:
9922         case OMP_CLAUSE_ORDERED:
9923         case OMP_CLAUSE_DEFAULT:
9924         case OMP_CLAUSE_UNTIED:
9925         case OMP_CLAUSE_COLLAPSE:
9926           pc = &OMP_CLAUSE_CHAIN (c);
9927           continue;
9928
9929         default:
9930           gcc_unreachable ();
9931         }
9932
9933       if (!remove)
9934         {
9935           t = OMP_CLAUSE_DECL (c);
9936
9937           if (need_complete)
9938             {
9939               t = require_complete_type (t);
9940               if (t == error_mark_node)
9941                 remove = true;
9942             }
9943
9944           if (need_implicitly_determined)
9945             {
9946               const char *share_name = NULL;
9947
9948               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
9949                 share_name = "threadprivate";
9950               else switch (c_omp_predetermined_sharing (t))
9951                 {
9952                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
9953                   break;
9954                 case OMP_CLAUSE_DEFAULT_SHARED:
9955                   share_name = "shared";
9956                   break;
9957                 case OMP_CLAUSE_DEFAULT_PRIVATE:
9958                   share_name = "private";
9959                   break;
9960                 default:
9961                   gcc_unreachable ();
9962                 }
9963               if (share_name)
9964                 {
9965                   error_at (OMP_CLAUSE_LOCATION (c),
9966                             "%qE is predetermined %qs for %qs",
9967                             t, share_name, name);
9968                   remove = true;
9969                 }
9970             }
9971         }
9972
9973       if (remove)
9974         *pc = OMP_CLAUSE_CHAIN (c);
9975       else
9976         pc = &OMP_CLAUSE_CHAIN (c);
9977     }
9978
9979   bitmap_obstack_release (NULL);
9980   return clauses;
9981 }
9982
9983 /* Make a variant type in the proper way for C/C++, propagating qualifiers
9984    down to the element type of an array.  */
9985
9986 tree
9987 c_build_qualified_type (tree type, int type_quals)
9988 {
9989   if (type == error_mark_node)
9990     return type;
9991
9992   if (TREE_CODE (type) == ARRAY_TYPE)
9993     {
9994       tree t;
9995       tree element_type = c_build_qualified_type (TREE_TYPE (type),
9996                                                   type_quals);
9997
9998       /* See if we already have an identically qualified type.  */
9999       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
10000         {
10001           if (TYPE_QUALS (strip_array_types (t)) == type_quals
10002               && TYPE_NAME (t) == TYPE_NAME (type)
10003               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
10004               && attribute_list_equal (TYPE_ATTRIBUTES (t),
10005                                        TYPE_ATTRIBUTES (type)))
10006             break;
10007         }
10008       if (!t)
10009         {
10010           tree domain = TYPE_DOMAIN (type);
10011
10012           t = build_variant_type_copy (type);
10013           TREE_TYPE (t) = element_type;
10014
10015           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
10016               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
10017             SET_TYPE_STRUCTURAL_EQUALITY (t);
10018           else if (TYPE_CANONICAL (element_type) != element_type
10019                    || (domain && TYPE_CANONICAL (domain) != domain))
10020             {
10021               tree unqualified_canon
10022                 = build_array_type (TYPE_CANONICAL (element_type),
10023                                     domain? TYPE_CANONICAL (domain)
10024                                           : NULL_TREE);
10025               TYPE_CANONICAL (t)
10026                 = c_build_qualified_type (unqualified_canon, type_quals);
10027             }
10028           else
10029             TYPE_CANONICAL (t) = t;
10030         }
10031       return t;
10032     }
10033
10034   /* A restrict-qualified pointer type must be a pointer to object or
10035      incomplete type.  Note that the use of POINTER_TYPE_P also allows
10036      REFERENCE_TYPEs, which is appropriate for C++.  */
10037   if ((type_quals & TYPE_QUAL_RESTRICT)
10038       && (!POINTER_TYPE_P (type)
10039           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
10040     {
10041       error ("invalid use of %<restrict%>");
10042       type_quals &= ~TYPE_QUAL_RESTRICT;
10043     }
10044
10045   return build_qualified_type (type, type_quals);
10046 }
10047
10048 /* Build a VA_ARG_EXPR for the C parser.  */
10049
10050 tree
10051 c_build_va_arg (location_t loc, tree expr, tree type)
10052 {
10053   if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
10054     warning_at (loc, OPT_Wc___compat,
10055                 "C++ requires promoted type, not enum type, in %<va_arg%>");
10056   return build_va_arg (loc, expr, type);
10057 }