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 "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_assign,
  53   ic_init,
  54   ic_return
  55 };
  56
  57 /* Whether we are building a boolean conversion inside
  58    convert_for_assignment, or some other late binary operation.  If
  59    build_binary_op is called (from code shared with C++) in this case,
  60    then the operands have already been folded and the result will not
  61    be folded again, so C_MAYBE_CONST_EXPR should not be generated.  */
  62 bool in_late_binary_op;
  63
  64 /* The level of nesting inside "__alignof__".  */
  65 int in_alignof;
  66
  67 /* The level of nesting inside "sizeof".  */
  68 int in_sizeof;
  69
  70 /* The level of nesting inside "typeof".  */
  71 int in_typeof;
  72
  73 struct c_label_context_se *label_context_stack_se;
  74 struct c_label_context_vm *label_context_stack_vm;
  75
  76 /* Nonzero if we've already printed a "missing braces around initializer"
  77    message within this initializer.  */
  78 static int missing_braces_mentioned;
  79
  80 static int require_constant_value;
  81 static int require_constant_elements;
  82
  83 static bool null_pointer_constant_p (const_tree);
  84 static tree qualify_type (tree, tree);
  85 static int tagged_types_tu_compatible_p (const_tree, const_tree);
  86 static int comp_target_types (tree, tree);
  87 static int function_types_compatible_p (const_tree, const_tree);
  88 static int type_lists_compatible_p (const_tree, const_tree);
  89 static tree lookup_field (tree, tree);
  90 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  91 static tree pointer_diff (tree, tree);
  92 static tree convert_for_assignment (tree, tree, enum impl_conv, bool,
  93                                     tree, tree, int);
  94 static tree valid_compound_expr_initializer (tree, tree);
  95 static void push_string (const char *);
  96 static void push_member_name (tree);
  97 static int spelling_length (void);
  98 static char *print_spelling (char *);
  99 static void warning_init (int, const char *);
 100 static tree digest_init (tree, tree, bool, bool, int);
 101 static void output_init_element (tree, bool, tree, tree, int, bool);
 102 static void output_pending_init_elements (int);
 103 static int set_designator (int);
 104 static void push_range_stack (tree);
 105 static void add_pending_init (tree, tree, bool);
 106 static void set_nonincremental_init (void);
 107 static void set_nonincremental_init_from_string (tree);
 108 static tree find_init_member (tree);
 109 static void readonly_error (tree, enum lvalue_use);
 110 static int lvalue_or_else (const_tree, enum lvalue_use);
 111 static int lvalue_p (const_tree);
 112 static void record_maybe_used_decl (tree);
 113 static int comptypes_internal (const_tree, const_tree);
 114 \f
 115 /* Return true if EXP is a null pointer constant, false otherwise.  */
 116
 117 static bool
 118 null_pointer_constant_p (const_tree expr)
 119 {
 120   /* This should really operate on c_expr structures, but they aren't
 121      yet available everywhere required.  */
 122   tree type = TREE_TYPE (expr);
 123   return (TREE_CODE (expr) == INTEGER_CST
 124           && !TREE_OVERFLOW (expr)
 125           && integer_zerop (expr)
 126           && (INTEGRAL_TYPE_P (type)
 127               || (TREE_CODE (type) == POINTER_TYPE
 128                   && VOID_TYPE_P (TREE_TYPE (type))
 129                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 130 }
 131
 132 /* EXPR may appear in an unevaluated part of an integer constant
 133    expression, but not in an evaluated part.  Wrap it in a
 134    C_MAYBE_CONST_EXPR, or mark it with TREE_OVERFLOW if it is just an
 135    INTEGER_CST and we cannot create a C_MAYBE_CONST_EXPR.  */
 136
 137 static tree
 138 note_integer_operands (tree expr)
 139 {
 140   tree ret;
 141   if (TREE_CODE (expr) == INTEGER_CST && in_late_binary_op)
 142     {
 143       ret = copy_node (expr);
 144       TREE_OVERFLOW (ret) = 1;
 145     }
 146   else
 147     {
 148       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (expr), NULL_TREE, expr);
 149       C_MAYBE_CONST_EXPR_INT_OPERANDS (ret) = 1;
 150     }
 151   return ret;
 152 }
 153
 154 /* Having checked whether EXPR may appear in an unevaluated part of an
 155    integer constant expression and found that it may, remove any
 156    C_MAYBE_CONST_EXPR noting this fact and return the resulting
 157    expression.  */
 158
 159 static inline tree
 160 remove_c_maybe_const_expr (tree expr)
 161 {
 162   if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR)
 163     return C_MAYBE_CONST_EXPR_EXPR (expr);
 164   else
 165     return expr;
 166 }
 167
 168 \f/* This is a cache to hold if two types are compatible or not.  */
 169
 170 struct tagged_tu_seen_cache {
 171   const struct tagged_tu_seen_cache * next;
 172   const_tree t1;
 173   const_tree t2;
 174   /* The return value of tagged_types_tu_compatible_p if we had seen
 175      these two types already.  */
 176   int val;
 177 };
 178
 179 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 180 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 181
 182 /* Do `exp = require_complete_type (exp);' to make sure exp
 183    does not have an incomplete type.  (That includes void types.)  */
 184
 185 tree
 186 require_complete_type (tree value)
 187 {
 188   tree type = TREE_TYPE (value);
 189
 190   if (value == error_mark_node || type == error_mark_node)
 191     return error_mark_node;
 192
 193   /* First, detect a valid value with a complete type.  */
 194   if (COMPLETE_TYPE_P (type))
 195     return value;
 196
 197   c_incomplete_type_error (value, type);
 198   return error_mark_node;
 199 }
 200
 201 /* Print an error message for invalid use of an incomplete type.
 202    VALUE is the expression that was used (or 0 if that isn't known)
 203    and TYPE is the type that was invalid.  */
 204
 205 void
 206 c_incomplete_type_error (const_tree value, const_tree type)
 207 {
 208   const char *type_code_string;
 209
 210   /* Avoid duplicate error message.  */
 211   if (TREE_CODE (type) == ERROR_MARK)
 212     return;
 213
 214   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 215                      || TREE_CODE (value) == PARM_DECL))
 216     error ("%qD has an incomplete type", value);
 217   else
 218     {
 219     retry:
 220       /* We must print an error message.  Be clever about what it says.  */
 221
 222       switch (TREE_CODE (type))
 223         {
 224         case RECORD_TYPE:
 225           type_code_string = "struct";
 226           break;
 227
 228         case UNION_TYPE:
 229           type_code_string = "union";
 230           break;
 231
 232         case ENUMERAL_TYPE:
 233           type_code_string = "enum";
 234           break;
 235
 236         case VOID_TYPE:
 237           error ("invalid use of void expression");
 238           return;
 239
 240         case ARRAY_TYPE:
 241           if (TYPE_DOMAIN (type))
 242             {
 243               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 244                 {
 245                   error ("invalid use of flexible array member");
 246                   return;
 247                 }
 248               type = TREE_TYPE (type);
 249               goto retry;
 250             }
 251           error ("invalid use of array with unspecified bounds");
 252           return;
 253
 254         default:
 255           gcc_unreachable ();
 256         }
 257
 258       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 259         error ("invalid use of undefined type %<%s %E%>",
 260                type_code_string, TYPE_NAME (type));
 261       else
 262         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 263         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 264     }
 265 }
 266
 267 /* Given a type, apply default promotions wrt unnamed function
 268    arguments and return the new type.  */
 269
 270 tree
 271 c_type_promotes_to (tree type)
 272 {
 273   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 274     return double_type_node;
 275
 276   if (c_promoting_integer_type_p (type))
 277     {
 278       /* Preserve unsignedness if not really getting any wider.  */
 279       if (TYPE_UNSIGNED (type)
 280           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 281         return unsigned_type_node;
 282       return integer_type_node;
 283     }
 284
 285   return type;
 286 }
 287
 288 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 289    as well as those of TYPE.  */
 290
 291 static tree
 292 qualify_type (tree type, tree like)
 293 {
 294   return c_build_qualified_type (type,
 295                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 296 }
 297
 298 /* Return true iff the given tree T is a variable length array.  */
 299
 300 bool
 301 c_vla_type_p (const_tree t)
 302 {
 303   if (TREE_CODE (t) == ARRAY_TYPE
 304       && C_TYPE_VARIABLE_SIZE (t))
 305     return true;
 306   return false;
 307 }
 308 \f
 309 /* Return the composite type of two compatible types.
 310
 311    We assume that comptypes has already been done and returned
 312    nonzero; if that isn't so, this may crash.  In particular, we
 313    assume that qualifiers match.  */
 314
 315 tree
 316 composite_type (tree t1, tree t2)
 317 {
 318   enum tree_code code1;
 319   enum tree_code code2;
 320   tree attributes;
 321
 322   /* Save time if the two types are the same.  */
 323
 324   if (t1 == t2) return t1;
 325
 326   /* If one type is nonsense, use the other.  */
 327   if (t1 == error_mark_node)
 328     return t2;
 329   if (t2 == error_mark_node)
 330     return t1;
 331
 332   code1 = TREE_CODE (t1);
 333   code2 = TREE_CODE (t2);
 334
 335   /* Merge the attributes.  */
 336   attributes = targetm.merge_type_attributes (t1, t2);
 337
 338   /* If one is an enumerated type and the other is the compatible
 339      integer type, the composite type might be either of the two
 340      (DR#013 question 3).  For consistency, use the enumerated type as
 341      the composite type.  */
 342
 343   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 344     return t1;
 345   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 346     return t2;
 347
 348   gcc_assert (code1 == code2);
 349
 350   switch (code1)
 351     {
 352     case POINTER_TYPE:
 353       /* For two pointers, do this recursively on the target type.  */
 354       {
 355         tree pointed_to_1 = TREE_TYPE (t1);
 356         tree pointed_to_2 = TREE_TYPE (t2);
 357         tree target = composite_type (pointed_to_1, pointed_to_2);
 358         t1 = build_pointer_type (target);
 359         t1 = build_type_attribute_variant (t1, attributes);
 360         return qualify_type (t1, t2);
 361       }
 362
 363     case ARRAY_TYPE:
 364       {
 365         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 366         int quals;
 367         tree unqual_elt;
 368         tree d1 = TYPE_DOMAIN (t1);
 369         tree d2 = TYPE_DOMAIN (t2);
 370         bool d1_variable, d2_variable;
 371         bool d1_zero, d2_zero;
 372         bool t1_complete, t2_complete;
 373
 374         /* We should not have any type quals on arrays at all.  */
 375         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 376
 377         t1_complete = COMPLETE_TYPE_P (t1);
 378         t2_complete = COMPLETE_TYPE_P (t2);
 379
 380         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 381         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 382
 383         d1_variable = (!d1_zero
 384                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 385                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 386         d2_variable = (!d2_zero
 387                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 388                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 389         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 390         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 391
 392         /* Save space: see if the result is identical to one of the args.  */
 393         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 394             && (d2_variable || d2_zero || !d1_variable))
 395           return build_type_attribute_variant (t1, attributes);
 396         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 397             && (d1_variable || d1_zero || !d2_variable))
 398           return build_type_attribute_variant (t2, attributes);
 399
 400         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 401           return build_type_attribute_variant (t1, attributes);
 402         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 403           return build_type_attribute_variant (t2, attributes);
 404
 405         /* Merge the element types, and have a size if either arg has
 406            one.  We may have qualifiers on the element types.  To set
 407            up TYPE_MAIN_VARIANT correctly, we need to form the
 408            composite of the unqualified types and add the qualifiers
 409            back at the end.  */
 410         quals = TYPE_QUALS (strip_array_types (elt));
 411         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 412         t1 = build_array_type (unqual_elt,
 413                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 414                                              && (d2_variable
 415                                                  || d2_zero
 416                                                  || !d1_variable))
 417                                             ? t1
 418                                             : t2));
 419         /* Ensure a composite type involving a zero-length array type
 420            is a zero-length type not an incomplete type.  */
 421         if (d1_zero && d2_zero
 422             && (t1_complete || t2_complete)
 423             && !COMPLETE_TYPE_P (t1))
 424           {
 425             TYPE_SIZE (t1) = bitsize_zero_node;
 426             TYPE_SIZE_UNIT (t1) = size_zero_node;
 427           }
 428         t1 = c_build_qualified_type (t1, quals);
 429         return build_type_attribute_variant (t1, attributes);
 430       }
 431
 432     case ENUMERAL_TYPE:
 433     case RECORD_TYPE:
 434     case UNION_TYPE:
 435       if (attributes != NULL)
 436         {
 437           /* Try harder not to create a new aggregate type.  */
 438           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 439             return t1;
 440           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 441             return t2;
 442         }
 443       return build_type_attribute_variant (t1, attributes);
 444
 445     case FUNCTION_TYPE:
 446       /* Function types: prefer the one that specified arg types.
 447          If both do, merge the arg types.  Also merge the return types.  */
 448       {
 449         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 450         tree p1 = TYPE_ARG_TYPES (t1);
 451         tree p2 = TYPE_ARG_TYPES (t2);
 452         int len;
 453         tree newargs, n;
 454         int i;
 455
 456         /* Save space: see if the result is identical to one of the args.  */
 457         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 458           return build_type_attribute_variant (t1, attributes);
 459         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 460           return build_type_attribute_variant (t2, attributes);
 461
 462         /* Simple way if one arg fails to specify argument types.  */
 463         if (TYPE_ARG_TYPES (t1) == 0)
 464          {
 465             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 466             t1 = build_type_attribute_variant (t1, attributes);
 467             return qualify_type (t1, t2);
 468          }
 469         if (TYPE_ARG_TYPES (t2) == 0)
 470          {
 471            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 472            t1 = build_type_attribute_variant (t1, attributes);
 473            return qualify_type (t1, t2);
 474          }
 475
 476         /* If both args specify argument types, we must merge the two
 477            lists, argument by argument.  */
 478         /* Tell global_bindings_p to return false so that variable_size
 479            doesn't die on VLAs in parameter types.  */
 480         c_override_global_bindings_to_false = true;
 481
 482         len = list_length (p1);
 483         newargs = 0;
 484
 485         for (i = 0; i < len; i++)
 486           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 487
 488         n = newargs;
 489
 490         for (; p1;
 491              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 492           {
 493             /* A null type means arg type is not specified.
 494                Take whatever the other function type has.  */
 495             if (TREE_VALUE (p1) == 0)
 496               {
 497                 TREE_VALUE (n) = TREE_VALUE (p2);
 498                 goto parm_done;
 499               }
 500             if (TREE_VALUE (p2) == 0)
 501               {
 502                 TREE_VALUE (n) = TREE_VALUE (p1);
 503                 goto parm_done;
 504               }
 505
 506             /* Given  wait (union {union wait *u; int *i} *)
 507                and  wait (union wait *),
 508                prefer  union wait *  as type of parm.  */
 509             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 510                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 511               {
 512                 tree memb;
 513                 tree mv2 = TREE_VALUE (p2);
 514                 if (mv2 && mv2 != error_mark_node
 515                     && TREE_CODE (mv2) != ARRAY_TYPE)
 516                   mv2 = TYPE_MAIN_VARIANT (mv2);
 517                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 518                      memb; memb = TREE_CHAIN (memb))
 519                   {
 520                     tree mv3 = TREE_TYPE (memb);
 521                     if (mv3 && mv3 != error_mark_node
 522                         && TREE_CODE (mv3) != ARRAY_TYPE)
 523                       mv3 = TYPE_MAIN_VARIANT (mv3);
 524                     if (comptypes (mv3, mv2))
 525                       {
 526                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 527                                                          TREE_VALUE (p2));
 528                         pedwarn (input_location, OPT_pedantic,
 529                                  "function types not truly compatible in ISO C");
 530                         goto parm_done;
 531                       }
 532                   }
 533               }
 534             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 535                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 536               {
 537                 tree memb;
 538                 tree mv1 = TREE_VALUE (p1);
 539                 if (mv1 && mv1 != error_mark_node
 540                     && TREE_CODE (mv1) != ARRAY_TYPE)
 541                   mv1 = TYPE_MAIN_VARIANT (mv1);
 542                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 543                      memb; memb = TREE_CHAIN (memb))
 544                   {
 545                     tree mv3 = TREE_TYPE (memb);
 546                     if (mv3 && mv3 != error_mark_node
 547                         && TREE_CODE (mv3) != ARRAY_TYPE)
 548                       mv3 = TYPE_MAIN_VARIANT (mv3);
 549                     if (comptypes (mv3, mv1))
 550                       {
 551                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 552                                                          TREE_VALUE (p1));
 553                         pedwarn (input_location, OPT_pedantic,
 554                                  "function types not truly compatible in ISO C");
 555                         goto parm_done;
 556                       }
 557                   }
 558               }
 559             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 560           parm_done: ;
 561           }
 562
 563         c_override_global_bindings_to_false = false;
 564         t1 = build_function_type (valtype, newargs);
 565         t1 = qualify_type (t1, t2);
 566         /* ... falls through ...  */
 567       }
 568
 569     default:
 570       return build_type_attribute_variant (t1, attributes);
 571     }
 572
 573 }
 574
 575 /* Return the type of a conditional expression between pointers to
 576    possibly differently qualified versions of compatible types.
 577
 578    We assume that comp_target_types has already been done and returned
 579    nonzero; if that isn't so, this may crash.  */
 580
 581 static tree
 582 common_pointer_type (tree t1, tree t2)
 583 {
 584   tree attributes;
 585   tree pointed_to_1, mv1;
 586   tree pointed_to_2, mv2;
 587   tree target;
 588   unsigned target_quals;
 589
 590   /* Save time if the two types are the same.  */
 591
 592   if (t1 == t2) return t1;
 593
 594   /* If one type is nonsense, use the other.  */
 595   if (t1 == error_mark_node)
 596     return t2;
 597   if (t2 == error_mark_node)
 598     return t1;
 599
 600   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 601               && TREE_CODE (t2) == POINTER_TYPE);
 602
 603   /* Merge the attributes.  */
 604   attributes = targetm.merge_type_attributes (t1, t2);
 605
 606   /* Find the composite type of the target types, and combine the
 607      qualifiers of the two types' targets.  Do not lose qualifiers on
 608      array element types by taking the TYPE_MAIN_VARIANT.  */
 609   mv1 = pointed_to_1 = TREE_TYPE (t1);
 610   mv2 = pointed_to_2 = TREE_TYPE (t2);
 611   if (TREE_CODE (mv1) != ARRAY_TYPE)
 612     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 613   if (TREE_CODE (mv2) != ARRAY_TYPE)
 614     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 615   target = composite_type (mv1, mv2);
 616
 617   /* For function types do not merge const qualifiers, but drop them
 618      if used inconsistently.  The middle-end uses these to mark const
 619      and noreturn functions.  */
 620   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 621     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 622   else
 623     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 624   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 625   return build_type_attribute_variant (t1, attributes);
 626 }
 627
 628 /* Return the common type for two arithmetic types under the usual
 629    arithmetic conversions.  The default conversions have already been
 630    applied, and enumerated types converted to their compatible integer
 631    types.  The resulting type is unqualified and has no attributes.
 632
 633    This is the type for the result of most arithmetic operations
 634    if the operands have the given two types.  */
 635
 636 static tree
 637 c_common_type (tree t1, tree t2)
 638 {
 639   enum tree_code code1;
 640   enum tree_code code2;
 641
 642   /* If one type is nonsense, use the other.  */
 643   if (t1 == error_mark_node)
 644     return t2;
 645   if (t2 == error_mark_node)
 646     return t1;
 647
 648   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 649     t1 = TYPE_MAIN_VARIANT (t1);
 650
 651   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 652     t2 = TYPE_MAIN_VARIANT (t2);
 653
 654   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 655     t1 = build_type_attribute_variant (t1, NULL_TREE);
 656
 657   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 658     t2 = build_type_attribute_variant (t2, NULL_TREE);
 659
 660   /* Save time if the two types are the same.  */
 661
 662   if (t1 == t2) return t1;
 663
 664   code1 = TREE_CODE (t1);
 665   code2 = TREE_CODE (t2);
 666
 667   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 668               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 669               || code1 == INTEGER_TYPE);
 670   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 671               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 672               || code2 == INTEGER_TYPE);
 673
 674   /* When one operand is a decimal float type, the other operand cannot be
 675      a generic float type or a complex type.  We also disallow vector types
 676      here.  */
 677   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 678       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 679     {
 680       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 681         {
 682           error ("can%'t mix operands of decimal float and vector types");
 683           return error_mark_node;
 684         }
 685       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 686         {
 687           error ("can%'t mix operands of decimal float and complex types");
 688           return error_mark_node;
 689         }
 690       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 691         {
 692           error ("can%'t mix operands of decimal float and other float types");
 693           return error_mark_node;
 694         }
 695     }
 696
 697   /* If one type is a vector type, return that type.  (How the usual
 698      arithmetic conversions apply to the vector types extension is not
 699      precisely specified.)  */
 700   if (code1 == VECTOR_TYPE)
 701     return t1;
 702
 703   if (code2 == VECTOR_TYPE)
 704     return t2;
 705
 706   /* If one type is complex, form the common type of the non-complex
 707      components, then make that complex.  Use T1 or T2 if it is the
 708      required type.  */
 709   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 710     {
 711       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 712       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 713       tree subtype = c_common_type (subtype1, subtype2);
 714
 715       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 716         return t1;
 717       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 718         return t2;
 719       else
 720         return build_complex_type (subtype);
 721     }
 722
 723   /* If only one is real, use it as the result.  */
 724
 725   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 726     return t1;
 727
 728   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 729     return t2;
 730
 731   /* If both are real and either are decimal floating point types, use
 732      the decimal floating point type with the greater precision. */
 733
 734   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 735     {
 736       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 737           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 738         return dfloat128_type_node;
 739       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 740                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 741         return dfloat64_type_node;
 742       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 743                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 744         return dfloat32_type_node;
 745     }
 746
 747   /* Deal with fixed-point types.  */
 748   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 749     {
 750       unsigned int unsignedp = 0, satp = 0;
 751       enum machine_mode m1, m2;
 752       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 753
 754       m1 = TYPE_MODE (t1);
 755       m2 = TYPE_MODE (t2);
 756
 757       /* If one input type is saturating, the result type is saturating.  */
 758       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 759         satp = 1;
 760
 761       /* If both fixed-point types are unsigned, the result type is unsigned.
 762          When mixing fixed-point and integer types, follow the sign of the
 763          fixed-point type.
 764          Otherwise, the result type is signed.  */
 765       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 766            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 767           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 768               && TYPE_UNSIGNED (t1))
 769           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 770               && TYPE_UNSIGNED (t2)))
 771         unsignedp = 1;
 772
 773       /* The result type is signed.  */
 774       if (unsignedp == 0)
 775         {
 776           /* If the input type is unsigned, we need to convert to the
 777              signed type.  */
 778           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 779             {
 780               enum mode_class mclass = (enum mode_class) 0;
 781               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 782                 mclass = MODE_FRACT;
 783               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 784                 mclass = MODE_ACCUM;
 785               else
 786                 gcc_unreachable ();
 787               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 788             }
 789           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 790             {
 791               enum mode_class mclass = (enum mode_class) 0;
 792               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 793                 mclass = MODE_FRACT;
 794               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 795                 mclass = MODE_ACCUM;
 796               else
 797                 gcc_unreachable ();
 798               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 799             }
 800         }
 801
 802       if (code1 == FIXED_POINT_TYPE)
 803         {
 804           fbit1 = GET_MODE_FBIT (m1);
 805           ibit1 = GET_MODE_IBIT (m1);
 806         }
 807       else
 808         {
 809           fbit1 = 0;
 810           /* Signed integers need to subtract one sign bit.  */
 811           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 812         }
 813
 814       if (code2 == FIXED_POINT_TYPE)
 815         {
 816           fbit2 = GET_MODE_FBIT (m2);
 817           ibit2 = GET_MODE_IBIT (m2);
 818         }
 819       else
 820         {
 821           fbit2 = 0;
 822           /* Signed integers need to subtract one sign bit.  */
 823           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 824         }
 825
 826       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 827       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 828       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 829                                                  satp);
 830     }
 831
 832   /* Both real or both integers; use the one with greater precision.  */
 833
 834   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 835     return t1;
 836   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 837     return t2;
 838
 839   /* Same precision.  Prefer long longs to longs to ints when the
 840      same precision, following the C99 rules on integer type rank
 841      (which are equivalent to the C90 rules for C90 types).  */
 842
 843   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 844       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 845     return long_long_unsigned_type_node;
 846
 847   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 848       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 849     {
 850       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 851         return long_long_unsigned_type_node;
 852       else
 853         return long_long_integer_type_node;
 854     }
 855
 856   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 857       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 858     return long_unsigned_type_node;
 859
 860   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 861       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 862     {
 863       /* But preserve unsignedness from the other type,
 864          since long cannot hold all the values of an unsigned int.  */
 865       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 866         return long_unsigned_type_node;
 867       else
 868         return long_integer_type_node;
 869     }
 870
 871   /* Likewise, prefer long double to double even if same size.  */
 872   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 873       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 874     return long_double_type_node;
 875
 876   /* Otherwise prefer the unsigned one.  */
 877
 878   if (TYPE_UNSIGNED (t1))
 879     return t1;
 880   else
 881     return t2;
 882 }
 883 \f
 884 /* Wrapper around c_common_type that is used by c-common.c and other
 885    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 886    are allowed here and are converted to their compatible integer types.
 887    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 888    preferably a non-Boolean type as the common type.  */
 889 tree
 890 common_type (tree t1, tree t2)
 891 {
 892   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 893     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 894   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 895     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 896
 897   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 898   if (TREE_CODE (t1) == BOOLEAN_TYPE
 899       && TREE_CODE (t2) == BOOLEAN_TYPE)
 900     return boolean_type_node;
 901
 902   /* If either type is BOOLEAN_TYPE, then return the other.  */
 903   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 904     return t2;
 905   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 906     return t1;
 907
 908   return c_common_type (t1, t2);
 909 }
 910
 911 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 912    or various other operations.  Return 2 if they are compatible
 913    but a warning may be needed if you use them together.  */
 914
 915 int
 916 comptypes (tree type1, tree type2)
 917 {
 918   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 919   int val;
 920
 921   val = comptypes_internal (type1, type2);
 922   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 923
 924   return val;
 925 }
 926 \f
 927 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 928    or various other operations.  Return 2 if they are compatible
 929    but a warning may be needed if you use them together.  This
 930    differs from comptypes, in that we don't free the seen types.  */
 931
 932 static int
 933 comptypes_internal (const_tree type1, const_tree type2)
 934 {
 935   const_tree t1 = type1;
 936   const_tree t2 = type2;
 937   int attrval, val;
 938
 939   /* Suppress errors caused by previously reported errors.  */
 940
 941   if (t1 == t2 || !t1 || !t2
 942       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 943     return 1;
 944
 945   /* If either type is the internal version of sizetype, return the
 946      language version.  */
 947   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 948       && TYPE_ORIG_SIZE_TYPE (t1))
 949     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 950
 951   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 952       && TYPE_ORIG_SIZE_TYPE (t2))
 953     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 954
 955
 956   /* Enumerated types are compatible with integer types, but this is
 957      not transitive: two enumerated types in the same translation unit
 958      are compatible with each other only if they are the same type.  */
 959
 960   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 961     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 962   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 963     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 964
 965   if (t1 == t2)
 966     return 1;
 967
 968   /* Different classes of types can't be compatible.  */
 969
 970   if (TREE_CODE (t1) != TREE_CODE (t2))
 971     return 0;
 972
 973   /* Qualifiers must match. C99 6.7.3p9 */
 974
 975   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 976     return 0;
 977
 978   /* Allow for two different type nodes which have essentially the same
 979      definition.  Note that we already checked for equality of the type
 980      qualifiers (just above).  */
 981
 982   if (TREE_CODE (t1) != ARRAY_TYPE
 983       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 984     return 1;
 985
 986   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 987   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 988      return 0;
 989
 990   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 991   val = 0;
 992
 993   switch (TREE_CODE (t1))
 994     {
 995     case POINTER_TYPE:
 996       /* Do not remove mode or aliasing information.  */
 997       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 998           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 999         break;
1000       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
1001              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
1002       break;
1003
1004     case FUNCTION_TYPE:
1005       val = function_types_compatible_p (t1, t2);
1006       break;
1007
1008     case ARRAY_TYPE:
1009       {
1010         tree d1 = TYPE_DOMAIN (t1);
1011         tree d2 = TYPE_DOMAIN (t2);
1012         bool d1_variable, d2_variable;
1013         bool d1_zero, d2_zero;
1014         val = 1;
1015
1016         /* Target types must match incl. qualifiers.  */
1017         if (TREE_TYPE (t1) != TREE_TYPE (t2)
1018             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
1019           return 0;
1020
1021         /* Sizes must match unless one is missing or variable.  */
1022         if (d1 == 0 || d2 == 0 || d1 == d2)
1023           break;
1024
1025         d1_zero = !TYPE_MAX_VALUE (d1);
1026         d2_zero = !TYPE_MAX_VALUE (d2);
1027
1028         d1_variable = (!d1_zero
1029                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
1030                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
1031         d2_variable = (!d2_zero
1032                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
1033                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
1034         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
1035         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
1036
1037         if (d1_variable || d2_variable)
1038           break;
1039         if (d1_zero && d2_zero)
1040           break;
1041         if (d1_zero || d2_zero
1042             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
1043             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
1044           val = 0;
1045
1046         break;
1047       }
1048
1049     case ENUMERAL_TYPE:
1050     case RECORD_TYPE:
1051     case UNION_TYPE:
1052       if (val != 1 && !same_translation_unit_p (t1, t2))
1053         {
1054           tree a1 = TYPE_ATTRIBUTES (t1);
1055           tree a2 = TYPE_ATTRIBUTES (t2);
1056
1057           if (! attribute_list_contained (a1, a2)
1058               && ! attribute_list_contained (a2, a1))
1059             break;
1060
1061           if (attrval != 2)
1062             return tagged_types_tu_compatible_p (t1, t2);
1063           val = tagged_types_tu_compatible_p (t1, t2);
1064         }
1065       break;
1066
1067     case VECTOR_TYPE:
1068       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1069             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1070       break;
1071
1072     default:
1073       break;
1074     }
1075   return attrval == 2 && val == 1 ? 2 : val;
1076 }
1077
1078 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1079    ignoring their qualifiers.  */
1080
1081 static int
1082 comp_target_types (tree ttl, tree ttr)
1083 {
1084   int val;
1085   tree mvl, mvr;
1086
1087   /* Do not lose qualifiers on element types of array types that are
1088      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1089   mvl = TREE_TYPE (ttl);
1090   mvr = TREE_TYPE (ttr);
1091   if (TREE_CODE (mvl) != ARRAY_TYPE)
1092     mvl = TYPE_MAIN_VARIANT (mvl);
1093   if (TREE_CODE (mvr) != ARRAY_TYPE)
1094     mvr = TYPE_MAIN_VARIANT (mvr);
1095   val = comptypes (mvl, mvr);
1096
1097   if (val == 2)
1098     pedwarn (input_location, OPT_pedantic, "types are not quite compatible");
1099   return val;
1100 }
1101 \f
1102 /* Subroutines of `comptypes'.  */
1103
1104 /* Determine whether two trees derive from the same translation unit.
1105    If the CONTEXT chain ends in a null, that tree's context is still
1106    being parsed, so if two trees have context chains ending in null,
1107    they're in the same translation unit.  */
1108 int
1109 same_translation_unit_p (const_tree t1, const_tree t2)
1110 {
1111   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1112     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1113       {
1114       case tcc_declaration:
1115         t1 = DECL_CONTEXT (t1); break;
1116       case tcc_type:
1117         t1 = TYPE_CONTEXT (t1); break;
1118       case tcc_exceptional:
1119         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1120       default: gcc_unreachable ();
1121       }
1122
1123   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1124     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1125       {
1126       case tcc_declaration:
1127         t2 = DECL_CONTEXT (t2); break;
1128       case tcc_type:
1129         t2 = TYPE_CONTEXT (t2); break;
1130       case tcc_exceptional:
1131         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1132       default: gcc_unreachable ();
1133       }
1134
1135   return t1 == t2;
1136 }
1137
1138 /* Allocate the seen two types, assuming that they are compatible. */
1139
1140 static struct tagged_tu_seen_cache *
1141 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1142 {
1143   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1144   tu->next = tagged_tu_seen_base;
1145   tu->t1 = t1;
1146   tu->t2 = t2;
1147
1148   tagged_tu_seen_base = tu;
1149
1150   /* The C standard says that two structures in different translation
1151      units are compatible with each other only if the types of their
1152      fields are compatible (among other things).  We assume that they
1153      are compatible until proven otherwise when building the cache.
1154      An example where this can occur is:
1155      struct a
1156      {
1157        struct a *next;
1158      };
1159      If we are comparing this against a similar struct in another TU,
1160      and did not assume they were compatible, we end up with an infinite
1161      loop.  */
1162   tu->val = 1;
1163   return tu;
1164 }
1165
1166 /* Free the seen types until we get to TU_TIL. */
1167
1168 static void
1169 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1170 {
1171   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1172   while (tu != tu_til)
1173     {
1174       const struct tagged_tu_seen_cache *const tu1
1175         = (const struct tagged_tu_seen_cache *) tu;
1176       tu = tu1->next;
1177       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1178     }
1179   tagged_tu_seen_base = tu_til;
1180 }
1181
1182 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1183    compatible.  If the two types are not the same (which has been
1184    checked earlier), this can only happen when multiple translation
1185    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1186    rules.  */
1187
1188 static int
1189 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1190 {
1191   tree s1, s2;
1192   bool needs_warning = false;
1193
1194   /* We have to verify that the tags of the types are the same.  This
1195      is harder than it looks because this may be a typedef, so we have
1196      to go look at the original type.  It may even be a typedef of a
1197      typedef...
1198      In the case of compiler-created builtin structs the TYPE_DECL
1199      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1200   while (TYPE_NAME (t1)
1201          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1202          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1203     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1204
1205   while (TYPE_NAME (t2)
1206          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1207          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1208     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1209
1210   /* C90 didn't have the requirement that the two tags be the same.  */
1211   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1212     return 0;
1213
1214   /* C90 didn't say what happened if one or both of the types were
1215      incomplete; we choose to follow C99 rules here, which is that they
1216      are compatible.  */
1217   if (TYPE_SIZE (t1) == NULL
1218       || TYPE_SIZE (t2) == NULL)
1219     return 1;
1220
1221   {
1222     const struct tagged_tu_seen_cache * tts_i;
1223     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1224       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1225         return tts_i->val;
1226   }
1227
1228   switch (TREE_CODE (t1))
1229     {
1230     case ENUMERAL_TYPE:
1231       {
1232         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1233         /* Speed up the case where the type values are in the same order.  */
1234         tree tv1 = TYPE_VALUES (t1);
1235         tree tv2 = TYPE_VALUES (t2);
1236
1237         if (tv1 == tv2)
1238           {
1239             return 1;
1240           }
1241
1242         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1243           {
1244             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1245               break;
1246             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1247               {
1248                 tu->val = 0;
1249                 return 0;
1250               }
1251           }
1252
1253         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1254           {
1255             return 1;
1256           }
1257         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1258           {
1259             tu->val = 0;
1260             return 0;
1261           }
1262
1263         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1264           {
1265             tu->val = 0;
1266             return 0;
1267           }
1268
1269         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1270           {
1271             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1272             if (s2 == NULL
1273                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1274               {
1275                 tu->val = 0;
1276                 return 0;
1277               }
1278           }
1279         return 1;
1280       }
1281
1282     case UNION_TYPE:
1283       {
1284         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1285         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1286           {
1287             tu->val = 0;
1288             return 0;
1289           }
1290
1291         /*  Speed up the common case where the fields are in the same order. */
1292         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1293              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1294           {
1295             int result;
1296
1297             if (DECL_NAME (s1) != DECL_NAME (s2))
1298               break;
1299             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1300
1301             if (result != 1 && !DECL_NAME (s1))
1302               break;
1303             if (result == 0)
1304               {
1305                 tu->val = 0;
1306                 return 0;
1307               }
1308             if (result == 2)
1309               needs_warning = true;
1310
1311             if (TREE_CODE (s1) == FIELD_DECL
1312                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1313                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1314               {
1315                 tu->val = 0;
1316                 return 0;
1317               }
1318           }
1319         if (!s1 && !s2)
1320           {
1321             tu->val = needs_warning ? 2 : 1;
1322             return tu->val;
1323           }
1324
1325         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1326           {
1327             bool ok = false;
1328
1329             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1330               if (DECL_NAME (s1) == DECL_NAME (s2))
1331                 {
1332                   int result;
1333
1334                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1335
1336                   if (result != 1 && !DECL_NAME (s1))
1337                     continue;
1338                   if (result == 0)
1339                     {
1340                       tu->val = 0;
1341                       return 0;
1342                     }
1343                   if (result == 2)
1344                     needs_warning = true;
1345
1346                   if (TREE_CODE (s1) == FIELD_DECL
1347                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1348                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1349                     break;
1350
1351                   ok = true;
1352                   break;
1353                 }
1354             if (!ok)
1355               {
1356                 tu->val = 0;
1357                 return 0;
1358               }
1359           }
1360         tu->val = needs_warning ? 2 : 10;
1361         return tu->val;
1362       }
1363
1364     case RECORD_TYPE:
1365       {
1366         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1367
1368         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1369              s1 && s2;
1370              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1371           {
1372             int result;
1373             if (TREE_CODE (s1) != TREE_CODE (s2)
1374                 || DECL_NAME (s1) != DECL_NAME (s2))
1375               break;
1376             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1377             if (result == 0)
1378               break;
1379             if (result == 2)
1380               needs_warning = true;
1381
1382             if (TREE_CODE (s1) == FIELD_DECL
1383                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1384                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1385               break;
1386           }
1387         if (s1 && s2)
1388           tu->val = 0;
1389         else
1390           tu->val = needs_warning ? 2 : 1;
1391         return tu->val;
1392       }
1393
1394     default:
1395       gcc_unreachable ();
1396     }
1397 }
1398
1399 /* Return 1 if two function types F1 and F2 are compatible.
1400    If either type specifies no argument types,
1401    the other must specify a fixed number of self-promoting arg types.
1402    Otherwise, if one type specifies only the number of arguments,
1403    the other must specify that number of self-promoting arg types.
1404    Otherwise, the argument types must match.  */
1405
1406 static int
1407 function_types_compatible_p (const_tree f1, const_tree f2)
1408 {
1409   tree args1, args2;
1410   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1411   int val = 1;
1412   int val1;
1413   tree ret1, ret2;
1414
1415   ret1 = TREE_TYPE (f1);
1416   ret2 = TREE_TYPE (f2);
1417
1418   /* 'volatile' qualifiers on a function's return type used to mean
1419      the function is noreturn.  */
1420   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1421     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1422   if (TYPE_VOLATILE (ret1))
1423     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1424                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1425   if (TYPE_VOLATILE (ret2))
1426     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1427                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1428   val = comptypes_internal (ret1, ret2);
1429   if (val == 0)
1430     return 0;
1431
1432   args1 = TYPE_ARG_TYPES (f1);
1433   args2 = TYPE_ARG_TYPES (f2);
1434
1435   /* An unspecified parmlist matches any specified parmlist
1436      whose argument types don't need default promotions.  */
1437
1438   if (args1 == 0)
1439     {
1440       if (!self_promoting_args_p (args2))
1441         return 0;
1442       /* If one of these types comes from a non-prototype fn definition,
1443          compare that with the other type's arglist.
1444          If they don't match, ask for a warning (but no error).  */
1445       if (TYPE_ACTUAL_ARG_TYPES (f1)
1446           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1447         val = 2;
1448       return val;
1449     }
1450   if (args2 == 0)
1451     {
1452       if (!self_promoting_args_p (args1))
1453         return 0;
1454       if (TYPE_ACTUAL_ARG_TYPES (f2)
1455           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1456         val = 2;
1457       return val;
1458     }
1459
1460   /* Both types have argument lists: compare them and propagate results.  */
1461   val1 = type_lists_compatible_p (args1, args2);
1462   return val1 != 1 ? val1 : val;
1463 }
1464
1465 /* Check two lists of types for compatibility,
1466    returning 0 for incompatible, 1 for compatible,
1467    or 2 for compatible with warning.  */
1468
1469 static int
1470 type_lists_compatible_p (const_tree args1, const_tree args2)
1471 {
1472   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1473   int val = 1;
1474   int newval = 0;
1475
1476   while (1)
1477     {
1478       tree a1, mv1, a2, mv2;
1479       if (args1 == 0 && args2 == 0)
1480         return val;
1481       /* If one list is shorter than the other,
1482          they fail to match.  */
1483       if (args1 == 0 || args2 == 0)
1484         return 0;
1485       mv1 = a1 = TREE_VALUE (args1);
1486       mv2 = a2 = TREE_VALUE (args2);
1487       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1488         mv1 = TYPE_MAIN_VARIANT (mv1);
1489       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1490         mv2 = TYPE_MAIN_VARIANT (mv2);
1491       /* A null pointer instead of a type
1492          means there is supposed to be an argument
1493          but nothing is specified about what type it has.
1494          So match anything that self-promotes.  */
1495       if (a1 == 0)
1496         {
1497           if (c_type_promotes_to (a2) != a2)
1498             return 0;
1499         }
1500       else if (a2 == 0)
1501         {
1502           if (c_type_promotes_to (a1) != a1)
1503             return 0;
1504         }
1505       /* If one of the lists has an error marker, ignore this arg.  */
1506       else if (TREE_CODE (a1) == ERROR_MARK
1507                || TREE_CODE (a2) == ERROR_MARK)
1508         ;
1509       else if (!(newval = comptypes_internal (mv1, mv2)))
1510         {
1511           /* Allow  wait (union {union wait *u; int *i} *)
1512              and  wait (union wait *)  to be compatible.  */
1513           if (TREE_CODE (a1) == UNION_TYPE
1514               && (TYPE_NAME (a1) == 0
1515                   || TYPE_TRANSPARENT_UNION (a1))
1516               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1517               && tree_int_cst_equal (TYPE_SIZE (a1),
1518                                      TYPE_SIZE (a2)))
1519             {
1520               tree memb;
1521               for (memb = TYPE_FIELDS (a1);
1522                    memb; memb = TREE_CHAIN (memb))
1523                 {
1524                   tree mv3 = TREE_TYPE (memb);
1525                   if (mv3 && mv3 != error_mark_node
1526                       && TREE_CODE (mv3) != ARRAY_TYPE)
1527                     mv3 = TYPE_MAIN_VARIANT (mv3);
1528                   if (comptypes_internal (mv3, mv2))
1529                     break;
1530                 }
1531               if (memb == 0)
1532                 return 0;
1533             }
1534           else if (TREE_CODE (a2) == UNION_TYPE
1535                    && (TYPE_NAME (a2) == 0
1536                        || TYPE_TRANSPARENT_UNION (a2))
1537                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1538                    && tree_int_cst_equal (TYPE_SIZE (a2),
1539                                           TYPE_SIZE (a1)))
1540             {
1541               tree memb;
1542               for (memb = TYPE_FIELDS (a2);
1543                    memb; memb = TREE_CHAIN (memb))
1544                 {
1545                   tree mv3 = TREE_TYPE (memb);
1546                   if (mv3 && mv3 != error_mark_node
1547                       && TREE_CODE (mv3) != ARRAY_TYPE)
1548                     mv3 = TYPE_MAIN_VARIANT (mv3);
1549                   if (comptypes_internal (mv3, mv1))
1550                     break;
1551                 }
1552               if (memb == 0)
1553                 return 0;
1554             }
1555           else
1556             return 0;
1557         }
1558
1559       /* comptypes said ok, but record if it said to warn.  */
1560       if (newval > val)
1561         val = newval;
1562
1563       args1 = TREE_CHAIN (args1);
1564       args2 = TREE_CHAIN (args2);
1565     }
1566 }
1567 \f
1568 /* Compute the size to increment a pointer by.  */
1569
1570 static tree
1571 c_size_in_bytes (const_tree type)
1572 {
1573   enum tree_code code = TREE_CODE (type);
1574
1575   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1576     return size_one_node;
1577
1578   if (!COMPLETE_OR_VOID_TYPE_P (type))
1579     {
1580       error ("arithmetic on pointer to an incomplete type");
1581       return size_one_node;
1582     }
1583
1584   /* Convert in case a char is more than one unit.  */
1585   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1586                      size_int (TYPE_PRECISION (char_type_node)
1587                                / BITS_PER_UNIT));
1588 }
1589 \f
1590 /* Return either DECL or its known constant value (if it has one).  */
1591
1592 tree
1593 decl_constant_value (tree decl)
1594 {
1595   if (/* Don't change a variable array bound or initial value to a constant
1596          in a place where a variable is invalid.  Note that DECL_INITIAL
1597          isn't valid for a PARM_DECL.  */
1598       current_function_decl != 0
1599       && TREE_CODE (decl) != PARM_DECL
1600       && !TREE_THIS_VOLATILE (decl)
1601       && TREE_READONLY (decl)
1602       && DECL_INITIAL (decl) != 0
1603       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1604       /* This is invalid if initial value is not constant.
1605          If it has either a function call, a memory reference,
1606          or a variable, then re-evaluating it could give different results.  */
1607       && TREE_CONSTANT (DECL_INITIAL (decl))
1608       /* Check for cases where this is sub-optimal, even though valid.  */
1609       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1610     return DECL_INITIAL (decl);
1611   return decl;
1612 }
1613
1614 /* Convert the array expression EXP to a pointer.  */
1615 static tree
1616 array_to_pointer_conversion (tree exp)
1617 {
1618   tree orig_exp = exp;
1619   tree type = TREE_TYPE (exp);
1620   tree adr;
1621   tree restype = TREE_TYPE (type);
1622   tree ptrtype;
1623
1624   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1625
1626   STRIP_TYPE_NOPS (exp);
1627
1628   if (TREE_NO_WARNING (orig_exp))
1629     TREE_NO_WARNING (exp) = 1;
1630
1631   ptrtype = build_pointer_type (restype);
1632
1633   if (TREE_CODE (exp) == INDIRECT_REF)
1634     return convert (ptrtype, TREE_OPERAND (exp, 0));
1635
1636   if (TREE_CODE (exp) == VAR_DECL)
1637     {
1638       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1639          ADDR_EXPR because it's the best way of representing what
1640          happens in C when we take the address of an array and place
1641          it in a pointer to the element type.  */
1642       adr = build1 (ADDR_EXPR, ptrtype, exp);
1643       if (!c_mark_addressable (exp))
1644         return error_mark_node;
1645       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1646       return adr;
1647     }
1648
1649   /* This way is better for a COMPONENT_REF since it can
1650      simplify the offset for a component.  */
1651   adr = build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 1);
1652   return convert (ptrtype, adr);
1653 }
1654
1655 /* Convert the function expression EXP to a pointer.  */
1656 static tree
1657 function_to_pointer_conversion (tree exp)
1658 {
1659   tree orig_exp = exp;
1660
1661   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1662
1663   STRIP_TYPE_NOPS (exp);
1664
1665   if (TREE_NO_WARNING (orig_exp))
1666     TREE_NO_WARNING (exp) = 1;
1667
1668   return build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 0);
1669 }
1670
1671 /* Perform the default conversion of arrays and functions to pointers.
1672    Return the result of converting EXP.  For any other expression, just
1673    return EXP.  */
1674
1675 struct c_expr
1676 default_function_array_conversion (struct c_expr exp)
1677 {
1678   tree orig_exp = exp.value;
1679   tree type = TREE_TYPE (exp.value);
1680   enum tree_code code = TREE_CODE (type);
1681
1682   switch (code)
1683     {
1684     case ARRAY_TYPE:
1685       {
1686         bool not_lvalue = false;
1687         bool lvalue_array_p;
1688
1689         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1690                 || CONVERT_EXPR_P (exp.value))
1691                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1692           {
1693             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1694               not_lvalue = true;
1695             exp.value = TREE_OPERAND (exp.value, 0);
1696           }
1697
1698         if (TREE_NO_WARNING (orig_exp))
1699           TREE_NO_WARNING (exp.value) = 1;
1700
1701         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1702         if (!flag_isoc99 && !lvalue_array_p)
1703           {
1704             /* Before C99, non-lvalue arrays do not decay to pointers.
1705                Normally, using such an array would be invalid; but it can
1706                be used correctly inside sizeof or as a statement expression.
1707                Thus, do not give an error here; an error will result later.  */
1708             return exp;
1709           }
1710
1711         exp.value = array_to_pointer_conversion (exp.value);
1712       }
1713       break;
1714     case FUNCTION_TYPE:
1715       exp.value = function_to_pointer_conversion (exp.value);
1716       break;
1717     default:
1718       break;
1719     }
1720
1721   return exp;
1722 }
1723
1724
1725 /* EXP is an expression of integer type.  Apply the integer promotions
1726    to it and return the promoted value.  */
1727
1728 tree
1729 perform_integral_promotions (tree exp)
1730 {
1731   tree type = TREE_TYPE (exp);
1732   enum tree_code code = TREE_CODE (type);
1733
1734   gcc_assert (INTEGRAL_TYPE_P (type));
1735
1736   /* Normally convert enums to int,
1737      but convert wide enums to something wider.  */
1738   if (code == ENUMERAL_TYPE)
1739     {
1740       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1741                                           TYPE_PRECISION (integer_type_node)),
1742                                      ((TYPE_PRECISION (type)
1743                                        >= TYPE_PRECISION (integer_type_node))
1744                                       && TYPE_UNSIGNED (type)));
1745
1746       return convert (type, exp);
1747     }
1748
1749   /* ??? This should no longer be needed now bit-fields have their
1750      proper types.  */
1751   if (TREE_CODE (exp) == COMPONENT_REF
1752       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1753       /* If it's thinner than an int, promote it like a
1754          c_promoting_integer_type_p, otherwise leave it alone.  */
1755       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1756                                TYPE_PRECISION (integer_type_node)))
1757     return convert (integer_type_node, exp);
1758
1759   if (c_promoting_integer_type_p (type))
1760     {
1761       /* Preserve unsignedness if not really getting any wider.  */
1762       if (TYPE_UNSIGNED (type)
1763           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1764         return convert (unsigned_type_node, exp);
1765
1766       return convert (integer_type_node, exp);
1767     }
1768
1769   return exp;
1770 }
1771
1772
1773 /* Perform default promotions for C data used in expressions.
1774    Enumeral types or short or char are converted to int.
1775    In addition, manifest constants symbols are replaced by their values.  */
1776
1777 tree
1778 default_conversion (tree exp)
1779 {
1780   tree orig_exp;
1781   tree type = TREE_TYPE (exp);
1782   enum tree_code code = TREE_CODE (type);
1783
1784   /* Functions and arrays have been converted during parsing.  */
1785   gcc_assert (code != FUNCTION_TYPE);
1786   if (code == ARRAY_TYPE)
1787     return exp;
1788
1789   /* Constants can be used directly unless they're not loadable.  */
1790   if (TREE_CODE (exp) == CONST_DECL)
1791     exp = DECL_INITIAL (exp);
1792
1793   /* Strip no-op conversions.  */
1794   orig_exp = exp;
1795   STRIP_TYPE_NOPS (exp);
1796
1797   if (TREE_NO_WARNING (orig_exp))
1798     TREE_NO_WARNING (exp) = 1;
1799
1800   if (code == VOID_TYPE)
1801     {
1802       error ("void value not ignored as it ought to be");
1803       return error_mark_node;
1804     }
1805
1806   exp = require_complete_type (exp);
1807   if (exp == error_mark_node)
1808     return error_mark_node;
1809
1810   if (INTEGRAL_TYPE_P (type))
1811     return perform_integral_promotions (exp);
1812
1813   return exp;
1814 }
1815 \f
1816 /* Look up COMPONENT in a structure or union DECL.
1817
1818    If the component name is not found, returns NULL_TREE.  Otherwise,
1819    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1820    stepping down the chain to the component, which is in the last
1821    TREE_VALUE of the list.  Normally the list is of length one, but if
1822    the component is embedded within (nested) anonymous structures or
1823    unions, the list steps down the chain to the component.  */
1824
1825 static tree
1826 lookup_field (tree decl, tree component)
1827 {
1828   tree type = TREE_TYPE (decl);
1829   tree field;
1830
1831   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1832      to the field elements.  Use a binary search on this array to quickly
1833      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1834      will always be set for structures which have many elements.  */
1835
1836   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1837     {
1838       int bot, top, half;
1839       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1840
1841       field = TYPE_FIELDS (type);
1842       bot = 0;
1843       top = TYPE_LANG_SPECIFIC (type)->s->len;
1844       while (top - bot > 1)
1845         {
1846           half = (top - bot + 1) >> 1;
1847           field = field_array[bot+half];
1848
1849           if (DECL_NAME (field) == NULL_TREE)
1850             {
1851               /* Step through all anon unions in linear fashion.  */
1852               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1853                 {
1854                   field = field_array[bot++];
1855                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1856                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1857                     {
1858                       tree anon = lookup_field (field, component);
1859
1860                       if (anon)
1861                         return tree_cons (NULL_TREE, field, anon);
1862                     }
1863                 }
1864
1865               /* Entire record is only anon unions.  */
1866               if (bot > top)
1867                 return NULL_TREE;
1868
1869               /* Restart the binary search, with new lower bound.  */
1870               continue;
1871             }
1872
1873           if (DECL_NAME (field) == component)
1874             break;
1875           if (DECL_NAME (field) < component)
1876             bot += half;
1877           else
1878             top = bot + half;
1879         }
1880
1881       if (DECL_NAME (field_array[bot]) == component)
1882         field = field_array[bot];
1883       else if (DECL_NAME (field) != component)
1884         return NULL_TREE;
1885     }
1886   else
1887     {
1888       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1889         {
1890           if (DECL_NAME (field) == NULL_TREE
1891               && (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           if (DECL_NAME (field) == component)
1901             break;
1902         }
1903
1904       if (field == NULL_TREE)
1905         return NULL_TREE;
1906     }
1907
1908   return tree_cons (NULL_TREE, field, NULL_TREE);
1909 }
1910
1911 /* Make an expression to refer to the COMPONENT field of
1912    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1913
1914 tree
1915 build_component_ref (tree datum, tree component)
1916 {
1917   tree type = TREE_TYPE (datum);
1918   enum tree_code code = TREE_CODE (type);
1919   tree field = NULL;
1920   tree ref;
1921   bool datum_lvalue = lvalue_p (datum);
1922
1923   if (!objc_is_public (datum, component))
1924     return error_mark_node;
1925
1926   /* See if there is a field or component with name COMPONENT.  */
1927
1928   if (code == RECORD_TYPE || code == UNION_TYPE)
1929     {
1930       if (!COMPLETE_TYPE_P (type))
1931         {
1932           c_incomplete_type_error (NULL_TREE, type);
1933           return error_mark_node;
1934         }
1935
1936       field = lookup_field (datum, component);
1937
1938       if (!field)
1939         {
1940           error ("%qT has no member named %qE", type, component);
1941           return error_mark_node;
1942         }
1943
1944       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1945          This might be better solved in future the way the C++ front
1946          end does it - by giving the anonymous entities each a
1947          separate name and type, and then have build_component_ref
1948          recursively call itself.  We can't do that here.  */
1949       do
1950         {
1951           tree subdatum = TREE_VALUE (field);
1952           int quals;
1953           tree subtype;
1954           bool use_datum_quals;
1955
1956           if (TREE_TYPE (subdatum) == error_mark_node)
1957             return error_mark_node;
1958
1959           /* If this is an rvalue, it does not have qualifiers in C
1960              standard terms and we must avoid propagating such
1961              qualifiers down to a non-lvalue array that is then
1962              converted to a pointer.  */
1963           use_datum_quals = (datum_lvalue
1964                              || TREE_CODE (TREE_TYPE (subdatum)) != ARRAY_TYPE);
1965
1966           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1967           if (use_datum_quals)
1968             quals |= TYPE_QUALS (TREE_TYPE (datum));
1969           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1970
1971           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1972                         NULL_TREE);
1973           if (TREE_READONLY (subdatum)
1974               || (use_datum_quals && TREE_READONLY (datum)))
1975             TREE_READONLY (ref) = 1;
1976           if (TREE_THIS_VOLATILE (subdatum)
1977               || (use_datum_quals && TREE_THIS_VOLATILE (datum)))
1978             TREE_THIS_VOLATILE (ref) = 1;
1979
1980           if (TREE_DEPRECATED (subdatum))
1981             warn_deprecated_use (subdatum);
1982
1983           datum = ref;
1984
1985           field = TREE_CHAIN (field);
1986         }
1987       while (field);
1988
1989       return ref;
1990     }
1991   else if (code != ERROR_MARK)
1992     error ("request for member %qE in something not a structure or union",
1993            component);
1994
1995   return error_mark_node;
1996 }
1997 \f
1998 /* Given an expression PTR for a pointer, return an expression
1999    for the value pointed to.
2000    ERRORSTRING is the name of the operator to appear in error messages.
2001
2002    LOC is the location to use for the generated tree.  */
2003
2004 tree
2005 build_indirect_ref (location_t loc, tree ptr, const char *errorstring)
2006 {
2007   tree pointer = default_conversion (ptr);
2008   tree type = TREE_TYPE (pointer);
2009   tree ref;
2010
2011   if (TREE_CODE (type) == POINTER_TYPE)
2012     {
2013       if (CONVERT_EXPR_P (pointer)
2014           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
2015         {
2016           /* If a warning is issued, mark it to avoid duplicates from
2017              the backend.  This only needs to be done at
2018              warn_strict_aliasing > 2.  */
2019           if (warn_strict_aliasing > 2)
2020             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
2021                                          type, TREE_OPERAND (pointer, 0)))
2022               TREE_NO_WARNING (pointer) = 1;
2023         }
2024
2025       if (TREE_CODE (pointer) == ADDR_EXPR
2026           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
2027               == TREE_TYPE (type)))
2028         {
2029           ref = TREE_OPERAND (pointer, 0);
2030           protected_set_expr_location (ref, loc);
2031           return ref;
2032         }
2033       else
2034         {
2035           tree t = TREE_TYPE (type);
2036
2037           ref = build1 (INDIRECT_REF, t, pointer);
2038
2039           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2040             {
2041               error_at (loc, "dereferencing pointer to incomplete type");
2042               return error_mark_node;
2043             }
2044           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2045             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2046
2047           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2048              so that we get the proper error message if the result is used
2049              to assign to.  Also, &* is supposed to be a no-op.
2050              And ANSI C seems to specify that the type of the result
2051              should be the const type.  */
2052           /* A de-reference of a pointer to const is not a const.  It is valid
2053              to change it via some other pointer.  */
2054           TREE_READONLY (ref) = TYPE_READONLY (t);
2055           TREE_SIDE_EFFECTS (ref)
2056             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2057           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2058           protected_set_expr_location (ref, loc);
2059           return ref;
2060         }
2061     }
2062   else if (TREE_CODE (pointer) != ERROR_MARK)
2063     error_at (loc,
2064               "invalid type argument of %qs (have %qT)", errorstring, type);
2065   return error_mark_node;
2066 }
2067
2068 /* This handles expressions of the form "a[i]", which denotes
2069    an array reference.
2070
2071    This is logically equivalent in C to *(a+i), but we may do it differently.
2072    If A is a variable or a member, we generate a primitive ARRAY_REF.
2073    This avoids forcing the array out of registers, and can work on
2074    arrays that are not lvalues (for example, members of structures returned
2075    by functions).
2076
2077    LOC is the location to use for the returned expression.  */
2078
2079 tree
2080 build_array_ref (tree array, tree index, location_t loc)
2081 {
2082   tree ret;
2083   bool swapped = false;
2084   if (TREE_TYPE (array) == error_mark_node
2085       || TREE_TYPE (index) == error_mark_node)
2086     return error_mark_node;
2087
2088   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2089       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2090     {
2091       tree temp;
2092       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2093           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2094         {
2095           error_at (loc, "subscripted value is neither array nor pointer");
2096           return error_mark_node;
2097         }
2098       temp = array;
2099       array = index;
2100       index = temp;
2101       swapped = true;
2102     }
2103
2104   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2105     {
2106       error_at (loc, "array subscript is not an integer");
2107       return error_mark_node;
2108     }
2109
2110   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2111     {
2112       error_at (loc, "subscripted value is pointer to function");
2113       return error_mark_node;
2114     }
2115
2116   /* ??? Existing practice has been to warn only when the char
2117      index is syntactically the index, not for char[array].  */
2118   if (!swapped)
2119      warn_array_subscript_with_type_char (index);
2120
2121   /* Apply default promotions *after* noticing character types.  */
2122   index = default_conversion (index);
2123
2124   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2125
2126   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2127     {
2128       tree rval, type;
2129
2130       /* An array that is indexed by a non-constant
2131          cannot be stored in a register; we must be able to do
2132          address arithmetic on its address.
2133          Likewise an array of elements of variable size.  */
2134       if (TREE_CODE (index) != INTEGER_CST
2135           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2136               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2137         {
2138           if (!c_mark_addressable (array))
2139             return error_mark_node;
2140         }
2141       /* An array that is indexed by a constant value which is not within
2142          the array bounds cannot be stored in a register either; because we
2143          would get a crash in store_bit_field/extract_bit_field when trying
2144          to access a non-existent part of the register.  */
2145       if (TREE_CODE (index) == INTEGER_CST
2146           && TYPE_DOMAIN (TREE_TYPE (array))
2147           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2148         {
2149           if (!c_mark_addressable (array))
2150             return error_mark_node;
2151         }
2152
2153       if (pedantic)
2154         {
2155           tree foo = array;
2156           while (TREE_CODE (foo) == COMPONENT_REF)
2157             foo = TREE_OPERAND (foo, 0);
2158           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2159             pedwarn (loc, OPT_pedantic,
2160                      "ISO C forbids subscripting %<register%> array");
2161           else if (!flag_isoc99 && !lvalue_p (foo))
2162             pedwarn (loc, OPT_pedantic,
2163                      "ISO C90 forbids subscripting non-lvalue array");
2164         }
2165
2166       type = TREE_TYPE (TREE_TYPE (array));
2167       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2168       /* Array ref is const/volatile if the array elements are
2169          or if the array is.  */
2170       TREE_READONLY (rval)
2171         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2172             | TREE_READONLY (array));
2173       TREE_SIDE_EFFECTS (rval)
2174         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2175             | TREE_SIDE_EFFECTS (array));
2176       TREE_THIS_VOLATILE (rval)
2177         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2178             /* This was added by rms on 16 Nov 91.
2179                It fixes  vol struct foo *a;  a->elts[1]
2180                in an inline function.
2181                Hope it doesn't break something else.  */
2182             | TREE_THIS_VOLATILE (array));
2183       ret = require_complete_type (rval);
2184       protected_set_expr_location (ret, loc);
2185       return ret;
2186     }
2187   else
2188     {
2189       tree ar = default_conversion (array);
2190
2191       if (ar == error_mark_node)
2192         return ar;
2193
2194       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2195       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2196
2197       return build_indirect_ref
2198         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2199          "array indexing");
2200     }
2201 }
2202 \f
2203 /* Build an external reference to identifier ID.  FUN indicates
2204    whether this will be used for a function call.  LOC is the source
2205    location of the identifier.  This sets *TYPE to the type of the
2206    identifier, which is not the same as the type of the returned value
2207    for CONST_DECLs defined as enum constants.  If the type of the
2208    identifier is not available, *TYPE is set to NULL.  */
2209 tree
2210 build_external_ref (tree id, int fun, location_t loc, tree *type)
2211 {
2212   tree ref;
2213   tree decl = lookup_name (id);
2214
2215   /* In Objective-C, an instance variable (ivar) may be preferred to
2216      whatever lookup_name() found.  */
2217   decl = objc_lookup_ivar (decl, id);
2218
2219   *type = NULL;
2220   if (decl && decl != error_mark_node)
2221     {
2222       ref = decl;
2223       *type = TREE_TYPE (ref);
2224     }
2225   else if (fun)
2226     /* Implicit function declaration.  */
2227     ref = implicitly_declare (id);
2228   else if (decl == error_mark_node)
2229     /* Don't complain about something that's already been
2230        complained about.  */
2231     return error_mark_node;
2232   else
2233     {
2234       undeclared_variable (id, loc);
2235       return error_mark_node;
2236     }
2237
2238   if (TREE_TYPE (ref) == error_mark_node)
2239     return error_mark_node;
2240
2241   if (TREE_DEPRECATED (ref))
2242     warn_deprecated_use (ref);
2243
2244   /* Recursive call does not count as usage.  */
2245   if (ref != current_function_decl)
2246     {
2247       TREE_USED (ref) = 1;
2248     }
2249
2250   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2251     {
2252       if (!in_sizeof && !in_typeof)
2253         C_DECL_USED (ref) = 1;
2254       else if (DECL_INITIAL (ref) == 0
2255                && DECL_EXTERNAL (ref)
2256                && !TREE_PUBLIC (ref))
2257         record_maybe_used_decl (ref);
2258     }
2259
2260   if (TREE_CODE (ref) == CONST_DECL)
2261     {
2262       used_types_insert (TREE_TYPE (ref));
2263       ref = DECL_INITIAL (ref);
2264       TREE_CONSTANT (ref) = 1;
2265     }
2266   else if (current_function_decl != 0
2267            && !DECL_FILE_SCOPE_P (current_function_decl)
2268            && (TREE_CODE (ref) == VAR_DECL
2269                || TREE_CODE (ref) == PARM_DECL
2270                || TREE_CODE (ref) == FUNCTION_DECL))
2271     {
2272       tree context = decl_function_context (ref);
2273
2274       if (context != 0 && context != current_function_decl)
2275         DECL_NONLOCAL (ref) = 1;
2276     }
2277   /* C99 6.7.4p3: An inline definition of a function with external
2278      linkage ... shall not contain a reference to an identifier with
2279      internal linkage.  */
2280   else if (current_function_decl != 0
2281            && DECL_DECLARED_INLINE_P (current_function_decl)
2282            && DECL_EXTERNAL (current_function_decl)
2283            && VAR_OR_FUNCTION_DECL_P (ref)
2284            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2285            && ! TREE_PUBLIC (ref)
2286            && DECL_CONTEXT (ref) != current_function_decl)
2287     pedwarn (loc, 0, "%qD is static but used in inline function %qD "
2288              "which is not static", ref, current_function_decl);
2289
2290   return ref;
2291 }
2292
2293 /* Record details of decls possibly used inside sizeof or typeof.  */
2294 struct maybe_used_decl
2295 {
2296   /* The decl.  */
2297   tree decl;
2298   /* The level seen at (in_sizeof + in_typeof).  */
2299   int level;
2300   /* The next one at this level or above, or NULL.  */
2301   struct maybe_used_decl *next;
2302 };
2303
2304 static struct maybe_used_decl *maybe_used_decls;
2305
2306 /* Record that DECL, an undefined static function reference seen
2307    inside sizeof or typeof, might be used if the operand of sizeof is
2308    a VLA type or the operand of typeof is a variably modified
2309    type.  */
2310
2311 static void
2312 record_maybe_used_decl (tree decl)
2313 {
2314   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2315   t->decl = decl;
2316   t->level = in_sizeof + in_typeof;
2317   t->next = maybe_used_decls;
2318   maybe_used_decls = t;
2319 }
2320
2321 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2322    USED is false, just discard them.  If it is true, mark them used
2323    (if no longer inside sizeof or typeof) or move them to the next
2324    level up (if still inside sizeof or typeof).  */
2325
2326 void
2327 pop_maybe_used (bool used)
2328 {
2329   struct maybe_used_decl *p = maybe_used_decls;
2330   int cur_level = in_sizeof + in_typeof;
2331   while (p && p->level > cur_level)
2332     {
2333       if (used)
2334         {
2335           if (cur_level == 0)
2336             C_DECL_USED (p->decl) = 1;
2337           else
2338             p->level = cur_level;
2339         }
2340       p = p->next;
2341     }
2342   if (!used || cur_level == 0)
2343     maybe_used_decls = p;
2344 }
2345
2346 /* Return the result of sizeof applied to EXPR.  */
2347
2348 struct c_expr
2349 c_expr_sizeof_expr (struct c_expr expr)
2350 {
2351   struct c_expr ret;
2352   if (expr.value == error_mark_node)
2353     {
2354       ret.value = error_mark_node;
2355       ret.original_code = ERROR_MARK;
2356       ret.original_type = NULL;
2357       pop_maybe_used (false);
2358     }
2359   else
2360     {
2361       bool expr_const_operands = true;
2362       tree folded_expr = c_fully_fold (expr.value, require_constant_value,
2363                                        &expr_const_operands);
2364       ret.value = c_sizeof (TREE_TYPE (folded_expr));
2365       ret.original_code = ERROR_MARK;
2366       ret.original_type = NULL;
2367       if (c_vla_type_p (TREE_TYPE (folded_expr)))
2368         {
2369           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2370           ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2371                               folded_expr, ret.value);
2372           C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !expr_const_operands;
2373         }
2374       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (folded_expr)));
2375     }
2376   return ret;
2377 }
2378
2379 /* Return the result of sizeof applied to T, a structure for the type
2380    name passed to sizeof (rather than the type itself).  */
2381
2382 struct c_expr
2383 c_expr_sizeof_type (struct c_type_name *t)
2384 {
2385   tree type;
2386   struct c_expr ret;
2387   tree type_expr = NULL_TREE;
2388   bool type_expr_const = true;
2389   type = groktypename (t, &type_expr, &type_expr_const);
2390   ret.value = c_sizeof (type);
2391   ret.original_code = ERROR_MARK;
2392   ret.original_type = NULL;
2393   if (type_expr && c_vla_type_p (type))
2394     {
2395       ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2396                           type_expr, ret.value);
2397       C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !type_expr_const;
2398     }
2399   pop_maybe_used (type != error_mark_node
2400                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2401   return ret;
2402 }
2403
2404 /* Build a function call to function FUNCTION with parameters PARAMS.
2405    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2406    TREE_VALUE of each node is a parameter-expression.
2407    FUNCTION's data type may be a function type or a pointer-to-function.  */
2408
2409 tree
2410 build_function_call (tree function, tree params)
2411 {
2412   tree fntype, fundecl = 0;
2413   tree name = NULL_TREE, result;
2414   tree tem;
2415   int nargs;
2416   tree *argarray;
2417
2418
2419   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2420   STRIP_TYPE_NOPS (function);
2421
2422   /* Convert anything with function type to a pointer-to-function.  */
2423   if (TREE_CODE (function) == FUNCTION_DECL)
2424     {
2425       /* Implement type-directed function overloading for builtins.
2426          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2427          handle all the type checking.  The result is a complete expression
2428          that implements this function call.  */
2429       tem = resolve_overloaded_builtin (function, params);
2430       if (tem)
2431         return tem;
2432
2433       name = DECL_NAME (function);
2434       fundecl = function;
2435     }
2436   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2437     function = function_to_pointer_conversion (function);
2438
2439   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2440      expressions, like those used for ObjC messenger dispatches.  */
2441   function = objc_rewrite_function_call (function, params);
2442
2443   function = c_fully_fold (function, false, NULL);
2444
2445   fntype = TREE_TYPE (function);
2446
2447   if (TREE_CODE (fntype) == ERROR_MARK)
2448     return error_mark_node;
2449
2450   if (!(TREE_CODE (fntype) == POINTER_TYPE
2451         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2452     {
2453       error ("called object %qE is not a function", function);
2454       return error_mark_node;
2455     }
2456
2457   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2458     current_function_returns_abnormally = 1;
2459
2460   /* fntype now gets the type of function pointed to.  */
2461   fntype = TREE_TYPE (fntype);
2462
2463   /* Convert the parameters to the types declared in the
2464      function prototype, or apply default promotions.  */
2465
2466   nargs = list_length (params);
2467   argarray = (tree *) alloca (nargs * sizeof (tree));
2468   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2469                              params, function, fundecl);
2470   if (nargs < 0)
2471     return error_mark_node;
2472
2473   /* Check that the function is called through a compatible prototype.
2474      If it is not, replace the call by a trap, wrapped up in a compound
2475      expression if necessary.  This has the nice side-effect to prevent
2476      the tree-inliner from generating invalid assignment trees which may
2477      blow up in the RTL expander later.  */
2478   if (CONVERT_EXPR_P (function)
2479       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2480       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2481       && !comptypes (fntype, TREE_TYPE (tem)))
2482     {
2483       tree return_type = TREE_TYPE (fntype);
2484       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2485                                        NULL_TREE);
2486       int i;
2487
2488       /* This situation leads to run-time undefined behavior.  We can't,
2489          therefore, simply error unless we can prove that all possible
2490          executions of the program must execute the code.  */
2491       if (warning (0, "function called through a non-compatible type"))
2492         /* We can, however, treat "undefined" any way we please.
2493            Call abort to encourage the user to fix the program.  */
2494         inform (input_location, "if this code is reached, the program will abort");
2495       /* Before the abort, allow the function arguments to exit or
2496          call longjmp.  */
2497       for (i = 0; i < nargs; i++)
2498         trap = build2 (COMPOUND_EXPR, void_type_node, argarray[i], trap);
2499
2500       if (VOID_TYPE_P (return_type))
2501         return trap;
2502       else
2503         {
2504           tree rhs;
2505
2506           if (AGGREGATE_TYPE_P (return_type))
2507             rhs = build_compound_literal (return_type,
2508                                           build_constructor (return_type, 0),
2509                                           false);
2510           else
2511             rhs = fold_convert (return_type, integer_zero_node);
2512
2513           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2514         }
2515     }
2516
2517   /* Check that arguments to builtin functions match the expectations.  */
2518   if (fundecl
2519       && DECL_BUILT_IN (fundecl)
2520       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2521       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2522     return error_mark_node;
2523
2524   /* Check that the arguments to the function are valid.  */
2525   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2526                             TYPE_ARG_TYPES (fntype));
2527
2528   if (name != NULL_TREE
2529       && !strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10))
2530     {
2531       if (require_constant_value)
2532         result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2533                                                     function, nargs, argarray);
2534       else
2535         result = fold_build_call_array (TREE_TYPE (fntype),
2536                                         function, nargs, argarray);
2537       if (TREE_CODE (result) == NOP_EXPR
2538           && TREE_CODE (TREE_OPERAND (result, 0)) == INTEGER_CST)
2539         STRIP_TYPE_NOPS (result);
2540     }
2541   else
2542     result = build_call_array (TREE_TYPE (fntype),
2543                                function, nargs, argarray);
2544
2545   if (VOID_TYPE_P (TREE_TYPE (result)))
2546     return result;
2547   return require_complete_type (result);
2548 }
2549 \f
2550 /* Convert the argument expressions in the list VALUES
2551    to the types in the list TYPELIST.  The resulting arguments are
2552    stored in the array ARGARRAY which has size NARGS.
2553
2554    If TYPELIST is exhausted, or when an element has NULL as its type,
2555    perform the default conversions.
2556
2557    PARMLIST is the chain of parm decls for the function being called.
2558    It may be 0, if that info is not available.
2559    It is used only for generating error messages.
2560
2561    FUNCTION is a tree for the called function.  It is used only for
2562    error messages, where it is formatted with %qE.
2563
2564    This is also where warnings about wrong number of args are generated.
2565
2566    VALUES is a chain of TREE_LIST nodes with the elements of the list
2567    in the TREE_VALUE slots of those nodes.
2568
2569    Returns the actual number of arguments processed (which may be less
2570    than NARGS in some error situations), or -1 on failure.  */
2571
2572 static int
2573 convert_arguments (int nargs, tree *argarray,
2574                    tree typelist, tree values, tree function, tree fundecl)
2575 {
2576   tree typetail, valtail;
2577   int parmnum;
2578   const bool type_generic = fundecl
2579     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2580   bool type_generic_remove_excess_precision = false;
2581   tree selector;
2582
2583   /* Change pointer to function to the function itself for
2584      diagnostics.  */
2585   if (TREE_CODE (function) == ADDR_EXPR
2586       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2587     function = TREE_OPERAND (function, 0);
2588
2589   /* Handle an ObjC selector specially for diagnostics.  */
2590   selector = objc_message_selector ();
2591
2592   /* For type-generic built-in functions, determine whether excess
2593      precision should be removed (classification) or not
2594      (comparison).  */
2595   if (type_generic
2596       && DECL_BUILT_IN (fundecl)
2597       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL)
2598     {
2599       switch (DECL_FUNCTION_CODE (fundecl))
2600         {
2601         case BUILT_IN_ISFINITE:
2602         case BUILT_IN_ISINF:
2603         case BUILT_IN_ISINF_SIGN:
2604         case BUILT_IN_ISNAN:
2605         case BUILT_IN_ISNORMAL:
2606         case BUILT_IN_FPCLASSIFY:
2607           type_generic_remove_excess_precision = true;
2608           break;
2609
2610         default:
2611           type_generic_remove_excess_precision = false;
2612           break;
2613         }
2614     }
2615
2616   /* Scan the given expressions and types, producing individual
2617      converted arguments and storing them in ARGARRAY.  */
2618
2619   for (valtail = values, typetail = typelist, parmnum = 0;
2620        valtail;
2621        valtail = TREE_CHAIN (valtail), parmnum++)
2622     {
2623       tree type = typetail ? TREE_VALUE (typetail) : 0;
2624       tree val = TREE_VALUE (valtail);
2625       tree valtype = TREE_TYPE (val);
2626       tree rname = function;
2627       int argnum = parmnum + 1;
2628       const char *invalid_func_diag;
2629       bool excess_precision = false;
2630       bool npc;
2631
2632       if (type == void_type_node)
2633         {
2634           error ("too many arguments to function %qE", function);
2635           return parmnum;
2636         }
2637
2638       if (selector && argnum > 2)
2639         {
2640           rname = selector;
2641           argnum -= 2;
2642         }
2643
2644       npc = null_pointer_constant_p (val);
2645
2646       /* If there is excess precision and a prototype, convert once to
2647          the required type rather than converting via the semantic
2648          type.  Likewise without a prototype a float value represented
2649          as long double should be converted once to double.  But for
2650          type-generic classification functions excess precision must
2651          be removed here.  */
2652       if (TREE_CODE (val) == EXCESS_PRECISION_EXPR
2653           && (type || !type_generic || !type_generic_remove_excess_precision))
2654         {
2655           val = TREE_OPERAND (val, 0);
2656           excess_precision = true;
2657         }
2658       val = c_fully_fold (val, false, NULL);
2659       STRIP_TYPE_NOPS (val);
2660
2661       val = require_complete_type (val);
2662
2663       if (type != 0)
2664         {
2665           /* Formal parm type is specified by a function prototype.  */
2666           tree parmval;
2667
2668           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2669             {
2670               error ("type of formal parameter %d is incomplete", parmnum + 1);
2671               parmval = val;
2672             }
2673           else
2674             {
2675               /* Optionally warn about conversions that
2676                  differ from the default conversions.  */
2677               if (warn_traditional_conversion || warn_traditional)
2678                 {
2679                   unsigned int formal_prec = TYPE_PRECISION (type);
2680
2681                   if (INTEGRAL_TYPE_P (type)
2682                       && TREE_CODE (valtype) == REAL_TYPE)
2683                     warning (0, "passing argument %d of %qE as integer "
2684                              "rather than floating due to prototype",
2685                              argnum, rname);
2686                   if (INTEGRAL_TYPE_P (type)
2687                       && TREE_CODE (valtype) == COMPLEX_TYPE)
2688                     warning (0, "passing argument %d of %qE as integer "
2689                              "rather than complex due to prototype",
2690                              argnum, rname);
2691                   else if (TREE_CODE (type) == COMPLEX_TYPE
2692                            && TREE_CODE (valtype) == REAL_TYPE)
2693                     warning (0, "passing argument %d of %qE as complex "
2694                              "rather than floating due to prototype",
2695                              argnum, rname);
2696                   else if (TREE_CODE (type) == REAL_TYPE
2697                            && INTEGRAL_TYPE_P (valtype))
2698                     warning (0, "passing argument %d of %qE as floating "
2699                              "rather than integer due to prototype",
2700                              argnum, rname);
2701                   else if (TREE_CODE (type) == COMPLEX_TYPE
2702                            && INTEGRAL_TYPE_P (valtype))
2703                     warning (0, "passing argument %d of %qE as complex "
2704                              "rather than integer due to prototype",
2705                              argnum, rname);
2706                   else if (TREE_CODE (type) == REAL_TYPE
2707                            && TREE_CODE (valtype) == COMPLEX_TYPE)
2708                     warning (0, "passing argument %d of %qE as floating "
2709                              "rather than complex due to prototype",
2710                              argnum, rname);
2711                   /* ??? At some point, messages should be written about
2712                      conversions between complex types, but that's too messy
2713                      to do now.  */
2714                   else if (TREE_CODE (type) == REAL_TYPE
2715                            && TREE_CODE (valtype) == REAL_TYPE)
2716                     {
2717                       /* Warn if any argument is passed as `float',
2718                          since without a prototype it would be `double'.  */
2719                       if (formal_prec == TYPE_PRECISION (float_type_node)
2720                           && type != dfloat32_type_node)
2721                         warning (0, "passing argument %d of %qE as %<float%> "
2722                                  "rather than %<double%> due to prototype",
2723                                  argnum, rname);
2724
2725                       /* Warn if mismatch between argument and prototype
2726                          for decimal float types.  Warn of conversions with
2727                          binary float types and of precision narrowing due to
2728                          prototype. */
2729                       else if (type != valtype
2730                                && (type == dfloat32_type_node
2731                                    || type == dfloat64_type_node
2732                                    || type == dfloat128_type_node
2733                                    || valtype == dfloat32_type_node
2734                                    || valtype == dfloat64_type_node
2735                                    || valtype == dfloat128_type_node)
2736                                && (formal_prec
2737                                    <= TYPE_PRECISION (valtype)
2738                                    || (type == dfloat128_type_node
2739                                        && (valtype
2740                                            != dfloat64_type_node
2741                                            && (valtype
2742                                                != dfloat32_type_node)))
2743                                    || (type == dfloat64_type_node
2744                                        && (valtype
2745                                            != dfloat32_type_node))))
2746                         warning (0, "passing argument %d of %qE as %qT "
2747                                  "rather than %qT due to prototype",
2748                                  argnum, rname, type, valtype);
2749
2750                     }
2751                   /* Detect integer changing in width or signedness.
2752                      These warnings are only activated with
2753                      -Wtraditional-conversion, not with -Wtraditional.  */
2754                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2755                            && INTEGRAL_TYPE_P (valtype))
2756                     {
2757                       tree would_have_been = default_conversion (val);
2758                       tree type1 = TREE_TYPE (would_have_been);
2759
2760                       if (TREE_CODE (type) == ENUMERAL_TYPE
2761                           && (TYPE_MAIN_VARIANT (type)
2762                               == TYPE_MAIN_VARIANT (valtype)))
2763                         /* No warning if function asks for enum
2764                            and the actual arg is that enum type.  */
2765                         ;
2766                       else if (formal_prec != TYPE_PRECISION (type1))
2767                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2768                                  "with different width due to prototype",
2769                                  argnum, rname);
2770                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2771                         ;
2772                       /* Don't complain if the formal parameter type
2773                          is an enum, because we can't tell now whether
2774                          the value was an enum--even the same enum.  */
2775                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2776                         ;
2777                       else if (TREE_CODE (val) == INTEGER_CST
2778                                && int_fits_type_p (val, type))
2779                         /* Change in signedness doesn't matter
2780                            if a constant value is unaffected.  */
2781                         ;
2782                       /* If the value is extended from a narrower
2783                          unsigned type, it doesn't matter whether we
2784                          pass it as signed or unsigned; the value
2785                          certainly is the same either way.  */
2786                       else if (TYPE_PRECISION (valtype) < TYPE_PRECISION (type)
2787                                && TYPE_UNSIGNED (valtype))
2788                         ;
2789                       else if (TYPE_UNSIGNED (type))
2790                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2791                                  "as unsigned due to prototype",
2792                                  argnum, rname);
2793                       else
2794                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2795                                  "as signed due to prototype", argnum, rname);
2796                     }
2797                 }
2798
2799               /* Possibly restore an EXCESS_PRECISION_EXPR for the
2800                  sake of better warnings from convert_and_check.  */
2801               if (excess_precision)
2802                 val = build1 (EXCESS_PRECISION_EXPR, valtype, val);
2803               parmval = convert_for_assignment (type, val, ic_argpass, npc,
2804                                                 fundecl, function,
2805                                                 parmnum + 1);
2806
2807               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2808                   && INTEGRAL_TYPE_P (type)
2809                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2810                 parmval = default_conversion (parmval);
2811             }
2812           argarray[parmnum] = parmval;
2813         }
2814       else if (TREE_CODE (valtype) == REAL_TYPE
2815                && (TYPE_PRECISION (valtype)
2816                    < TYPE_PRECISION (double_type_node))
2817                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (valtype)))
2818         {
2819           if (type_generic)
2820             argarray[parmnum] = val;
2821           else
2822             /* Convert `float' to `double'.  */
2823             argarray[parmnum] = convert (double_type_node, val);
2824         }
2825       else if (excess_precision && !type_generic)
2826         /* A "double" argument with excess precision being passed
2827            without a prototype or in variable arguments.  */
2828         argarray[parmnum] = convert (valtype, val);
2829       else if ((invalid_func_diag =
2830                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2831         {
2832           error (invalid_func_diag);
2833           return -1;
2834         }
2835       else
2836         /* Convert `short' and `char' to full-size `int'.  */
2837         argarray[parmnum] = default_conversion (val);
2838
2839       if (typetail)
2840         typetail = TREE_CHAIN (typetail);
2841     }
2842
2843   gcc_assert (parmnum == nargs);
2844
2845   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2846     {
2847       error ("too few arguments to function %qE", function);
2848       return -1;
2849     }
2850
2851   return parmnum;
2852 }
2853 \f
2854 /* This is the entry point used by the parser to build unary operators
2855    in the input.  CODE, a tree_code, specifies the unary operator, and
2856    ARG is the operand.  For unary plus, the C parser currently uses
2857    CONVERT_EXPR for code.
2858
2859    LOC is the location to use for the tree generated.
2860 */
2861
2862 struct c_expr
2863 parser_build_unary_op (enum tree_code code, struct c_expr arg, location_t loc)
2864 {
2865   struct c_expr result;
2866
2867   result.value = build_unary_op (loc, code, arg.value, 0);
2868   result.original_code = code;
2869   result.original_type = NULL;
2870
2871   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2872     overflow_warning (result.value);
2873
2874   return result;
2875 }
2876
2877 /* This is the entry point used by the parser to build binary operators
2878    in the input.  CODE, a tree_code, specifies the binary operator, and
2879    ARG1 and ARG2 are the operands.  In addition to constructing the
2880    expression, we check for operands that were written with other binary
2881    operators in a way that is likely to confuse the user.
2882
2883    LOCATION is the location of the binary operator.  */
2884
2885 struct c_expr
2886 parser_build_binary_op (location_t location, enum tree_code code,
2887                         struct c_expr arg1, struct c_expr arg2)
2888 {
2889   struct c_expr result;
2890
2891   enum tree_code code1 = arg1.original_code;
2892   enum tree_code code2 = arg2.original_code;
2893   tree type1 = (arg1.original_type
2894                 ? arg1.original_type
2895                 : TREE_TYPE (arg1.value));
2896   tree type2 = (arg2.original_type
2897                 ? arg2.original_type
2898                 : TREE_TYPE (arg2.value));
2899
2900   result.value = build_binary_op (location, code,
2901                                   arg1.value, arg2.value, 1);
2902   result.original_code = code;
2903   result.original_type = NULL;
2904
2905   if (TREE_CODE (result.value) == ERROR_MARK)
2906     return result;
2907
2908   if (location != UNKNOWN_LOCATION)
2909     protected_set_expr_location (result.value, location);
2910
2911   /* Check for cases such as x+y<<z which users are likely
2912      to misinterpret.  */
2913   if (warn_parentheses)
2914     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
2915
2916   if (TREE_CODE_CLASS (code1) != tcc_comparison)
2917     warn_logical_operator (code, arg1.value, arg2.value);
2918
2919   /* Warn about comparisons against string literals, with the exception
2920      of testing for equality or inequality of a string literal with NULL.  */
2921   if (code == EQ_EXPR || code == NE_EXPR)
2922     {
2923       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2924           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2925         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2926     }
2927   else if (TREE_CODE_CLASS (code) == tcc_comparison
2928            && (code1 == STRING_CST || code2 == STRING_CST))
2929     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2930
2931   if (TREE_OVERFLOW_P (result.value)
2932       && !TREE_OVERFLOW_P (arg1.value)
2933       && !TREE_OVERFLOW_P (arg2.value))
2934     overflow_warning (result.value);
2935
2936   /* Warn about comparisons of different enum types.  */
2937   if (warn_enum_compare
2938       && TREE_CODE_CLASS (code) == tcc_comparison
2939       && TREE_CODE (type1) == ENUMERAL_TYPE
2940       && TREE_CODE (type2) == ENUMERAL_TYPE
2941       && TYPE_MAIN_VARIANT (type1) != TYPE_MAIN_VARIANT (type2))
2942     warning_at (location, OPT_Wenum_compare,
2943                 "comparison between %qT and %qT",
2944                 type1, type2);
2945
2946   return result;
2947 }
2948 \f
2949 /* Return a tree for the difference of pointers OP0 and OP1.
2950    The resulting tree has type int.  */
2951
2952 static tree
2953 pointer_diff (tree op0, tree op1)
2954 {
2955   tree restype = ptrdiff_type_node;
2956
2957   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2958   tree con0, con1, lit0, lit1;
2959   tree orig_op1 = op1;
2960
2961   if (TREE_CODE (target_type) == VOID_TYPE)
2962     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2963              "pointer of type %<void *%> used in subtraction");
2964   if (TREE_CODE (target_type) == FUNCTION_TYPE)
2965     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2966              "pointer to a function used in subtraction");
2967
2968   /* If the conversion to ptrdiff_type does anything like widening or
2969      converting a partial to an integral mode, we get a convert_expression
2970      that is in the way to do any simplifications.
2971      (fold-const.c doesn't know that the extra bits won't be needed.
2972      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2973      different mode in place.)
2974      So first try to find a common term here 'by hand'; we want to cover
2975      at least the cases that occur in legal static initializers.  */
2976   if (CONVERT_EXPR_P (op0)
2977       && (TYPE_PRECISION (TREE_TYPE (op0))
2978           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2979     con0 = TREE_OPERAND (op0, 0);
2980   else
2981     con0 = op0;
2982   if (CONVERT_EXPR_P (op1)
2983       && (TYPE_PRECISION (TREE_TYPE (op1))
2984           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2985     con1 = TREE_OPERAND (op1, 0);
2986   else
2987     con1 = op1;
2988
2989   if (TREE_CODE (con0) == PLUS_EXPR)
2990     {
2991       lit0 = TREE_OPERAND (con0, 1);
2992       con0 = TREE_OPERAND (con0, 0);
2993     }
2994   else
2995     lit0 = integer_zero_node;
2996
2997   if (TREE_CODE (con1) == PLUS_EXPR)
2998     {
2999       lit1 = TREE_OPERAND (con1, 1);
3000       con1 = TREE_OPERAND (con1, 0);
3001     }
3002   else
3003     lit1 = integer_zero_node;
3004
3005   if (operand_equal_p (con0, con1, 0))
3006     {
3007       op0 = lit0;
3008       op1 = lit1;
3009     }
3010
3011
3012   /* First do the subtraction as integers;
3013      then drop through to build the divide operator.
3014      Do not do default conversions on the minus operator
3015      in case restype is a short type.  */
3016
3017   op0 = build_binary_op (input_location,
3018                          MINUS_EXPR, convert (restype, op0),
3019                          convert (restype, op1), 0);
3020   /* This generates an error if op1 is pointer to incomplete type.  */
3021   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
3022     error ("arithmetic on pointer to an incomplete type");
3023
3024   /* This generates an error if op0 is pointer to incomplete type.  */
3025   op1 = c_size_in_bytes (target_type);
3026
3027   /* Divide by the size, in easiest possible way.  */
3028   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
3029 }
3030 \f
3031 /* Construct and perhaps optimize a tree representation
3032    for a unary operation.  CODE, a tree_code, specifies the operation
3033    and XARG is the operand.
3034    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
3035    the default promotions (such as from short to int).
3036    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
3037    allows non-lvalues; this is only used to handle conversion of non-lvalue
3038    arrays to pointers in C99.
3039
3040    LOCATION is the location of the operator.  */
3041
3042 tree
3043 build_unary_op (location_t location,
3044                 enum tree_code code, tree xarg, int flag)
3045 {
3046   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3047   tree arg = xarg;
3048   tree argtype = 0;
3049   enum tree_code typecode;
3050   tree val;
3051   tree ret = error_mark_node;
3052   tree eptype = NULL_TREE;
3053   int noconvert = flag;
3054   const char *invalid_op_diag;
3055   bool int_operands;
3056
3057   int_operands = EXPR_INT_CONST_OPERANDS (xarg);
3058   if (int_operands)
3059     arg = remove_c_maybe_const_expr (arg);
3060
3061   if (code != ADDR_EXPR)
3062     arg = require_complete_type (arg);
3063
3064   typecode = TREE_CODE (TREE_TYPE (arg));
3065   if (typecode == ERROR_MARK)
3066     return error_mark_node;
3067   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
3068     typecode = INTEGER_TYPE;
3069
3070   if ((invalid_op_diag
3071        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
3072     {
3073       error_at (location, invalid_op_diag);
3074       return error_mark_node;
3075     }
3076
3077   if (TREE_CODE (arg) == EXCESS_PRECISION_EXPR)
3078     {
3079       eptype = TREE_TYPE (arg);
3080       arg = TREE_OPERAND (arg, 0);
3081     }
3082
3083   switch (code)
3084     {
3085     case CONVERT_EXPR:
3086       /* This is used for unary plus, because a CONVERT_EXPR
3087          is enough to prevent anybody from looking inside for
3088          associativity, but won't generate any code.  */
3089       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3090             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3091             || typecode == VECTOR_TYPE))
3092         {
3093           error_at (location, "wrong type argument to unary plus");
3094           return error_mark_node;
3095         }
3096       else if (!noconvert)
3097         arg = default_conversion (arg);
3098       arg = non_lvalue (arg);
3099       break;
3100
3101     case NEGATE_EXPR:
3102       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3103             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3104             || typecode == VECTOR_TYPE))
3105         {
3106           error_at (location, "wrong type argument to unary minus");
3107           return error_mark_node;
3108         }
3109       else if (!noconvert)
3110         arg = default_conversion (arg);
3111       break;
3112
3113     case BIT_NOT_EXPR:
3114       /* ~ works on integer types and non float vectors. */
3115       if (typecode == INTEGER_TYPE
3116           || (typecode == VECTOR_TYPE
3117               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
3118         {
3119           if (!noconvert)
3120             arg = default_conversion (arg);
3121         }
3122       else if (typecode == COMPLEX_TYPE)
3123         {
3124           code = CONJ_EXPR;
3125           pedwarn (location, OPT_pedantic,
3126                    "ISO C does not support %<~%> for complex conjugation");
3127           if (!noconvert)
3128             arg = default_conversion (arg);
3129         }
3130       else
3131         {
3132           error_at (location, "wrong type argument to bit-complement");
3133           return error_mark_node;
3134         }
3135       break;
3136
3137     case ABS_EXPR:
3138       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
3139         {
3140           error_at (location, "wrong type argument to abs");
3141           return error_mark_node;
3142         }
3143       else if (!noconvert)
3144         arg = default_conversion (arg);
3145       break;
3146
3147     case CONJ_EXPR:
3148       /* Conjugating a real value is a no-op, but allow it anyway.  */
3149       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3150             || typecode == COMPLEX_TYPE))
3151         {
3152           error_at (location, "wrong type argument to conjugation");
3153           return error_mark_node;
3154         }
3155       else if (!noconvert)
3156         arg = default_conversion (arg);
3157       break;
3158
3159     case TRUTH_NOT_EXPR:
3160       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3161           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3162           && typecode != COMPLEX_TYPE)
3163         {
3164           error_at (location,
3165                     "wrong type argument to unary exclamation mark");
3166           return error_mark_node;
3167         }
3168       arg = c_objc_common_truthvalue_conversion (location, arg);
3169       ret = invert_truthvalue (arg);
3170       goto return_build_unary_op;
3171
3172     case REALPART_EXPR:
3173       if (TREE_CODE (arg) == COMPLEX_CST)
3174         ret = TREE_REALPART (arg);
3175       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3176         ret = fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3177       else
3178         ret = arg;
3179       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3180         eptype = TREE_TYPE (eptype);
3181       goto return_build_unary_op;
3182
3183     case IMAGPART_EXPR:
3184       if (TREE_CODE (arg) == COMPLEX_CST)
3185         ret = TREE_IMAGPART (arg);
3186       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3187         ret = fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3188       else
3189         ret = omit_one_operand (TREE_TYPE (arg), integer_zero_node, arg);
3190       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3191         eptype = TREE_TYPE (eptype);
3192       goto return_build_unary_op;
3193
3194     case PREINCREMENT_EXPR:
3195     case POSTINCREMENT_EXPR:
3196     case PREDECREMENT_EXPR:
3197     case POSTDECREMENT_EXPR:
3198
3199       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3200         {
3201           tree inner = build_unary_op (location, code,
3202                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3203           if (inner == error_mark_node)
3204             return error_mark_node;
3205           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3206                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3207           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3208           C_MAYBE_CONST_EXPR_NON_CONST (ret) = 1;
3209           goto return_build_unary_op;
3210         }
3211
3212       /* Complain about anything that is not a true lvalue.  */
3213       if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3214                                   || code == POSTINCREMENT_EXPR)
3215                                  ? lv_increment
3216                                  : lv_decrement)))
3217         return error_mark_node;
3218
3219       /* Ensure the argument is fully folded inside any SAVE_EXPR.  */
3220       arg = c_fully_fold (arg, false, NULL);
3221
3222       /* Increment or decrement the real part of the value,
3223          and don't change the imaginary part.  */
3224       if (typecode == COMPLEX_TYPE)
3225         {
3226           tree real, imag;
3227
3228           pedwarn (location, OPT_pedantic,
3229                    "ISO C does not support %<++%> and %<--%> on complex types");
3230
3231           arg = stabilize_reference (arg);
3232           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3233           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3234           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3235           if (real == error_mark_node || imag == error_mark_node)
3236             return error_mark_node;
3237           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3238                         real, imag);
3239           goto return_build_unary_op;
3240         }
3241
3242       /* Report invalid types.  */
3243
3244       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3245           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3246         {
3247           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3248             error_at (location, "wrong type argument to increment");
3249           else
3250             error_at (location, "wrong type argument to decrement");
3251
3252           return error_mark_node;
3253         }
3254
3255       {
3256         tree inc;
3257
3258         argtype = TREE_TYPE (arg);
3259
3260         /* Compute the increment.  */
3261
3262         if (typecode == POINTER_TYPE)
3263           {
3264             /* If pointer target is an undefined struct,
3265                we just cannot know how to do the arithmetic.  */
3266             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3267               {
3268                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3269                   error_at (location,
3270                             "increment of pointer to unknown structure");
3271                 else
3272                   error_at (location,
3273                             "decrement of pointer to unknown structure");
3274               }
3275             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3276                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3277               {
3278                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3279                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3280                            "wrong type argument to increment");
3281                 else
3282                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3283                            "wrong type argument to decrement");
3284               }
3285
3286             inc = c_size_in_bytes (TREE_TYPE (argtype));
3287             inc = fold_convert (sizetype, inc);
3288           }
3289         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3290           {
3291             /* For signed fract types, we invert ++ to -- or
3292                -- to ++, and change inc from 1 to -1, because
3293                it is not possible to represent 1 in signed fract constants.
3294                For unsigned fract types, the result always overflows and
3295                we get an undefined (original) or the maximum value.  */
3296             if (code == PREINCREMENT_EXPR)
3297               code = PREDECREMENT_EXPR;
3298             else if (code == PREDECREMENT_EXPR)
3299               code = PREINCREMENT_EXPR;
3300             else if (code == POSTINCREMENT_EXPR)
3301               code = POSTDECREMENT_EXPR;
3302             else /* code == POSTDECREMENT_EXPR  */
3303               code = POSTINCREMENT_EXPR;
3304
3305             inc = integer_minus_one_node;
3306             inc = convert (argtype, inc);
3307           }
3308         else
3309           {
3310             inc = integer_one_node;
3311             inc = convert (argtype, inc);
3312           }
3313
3314         /* Report a read-only lvalue.  */
3315         if (TREE_READONLY (arg))
3316           {
3317             readonly_error (arg,
3318                             ((code == PREINCREMENT_EXPR
3319                               || code == POSTINCREMENT_EXPR)
3320                              ? lv_increment : lv_decrement));
3321             return error_mark_node;
3322           }
3323
3324         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3325           val = boolean_increment (code, arg);
3326         else
3327           val = build2 (code, TREE_TYPE (arg), arg, inc);
3328         TREE_SIDE_EFFECTS (val) = 1;
3329         if (TREE_CODE (val) != code)
3330           TREE_NO_WARNING (val) = 1;
3331         ret = val;
3332         goto return_build_unary_op;
3333       }
3334
3335     case ADDR_EXPR:
3336       /* Note that this operation never does default_conversion.  */
3337
3338       /* Let &* cancel out to simplify resulting code.  */
3339       if (TREE_CODE (arg) == INDIRECT_REF)
3340         {
3341           /* Don't let this be an lvalue.  */
3342           if (lvalue_p (TREE_OPERAND (arg, 0)))
3343             return non_lvalue (TREE_OPERAND (arg, 0));
3344           ret = TREE_OPERAND (arg, 0);
3345           goto return_build_unary_op;
3346         }
3347
3348       /* For &x[y], return x+y */
3349       if (TREE_CODE (arg) == ARRAY_REF)
3350         {
3351           tree op0 = TREE_OPERAND (arg, 0);
3352           if (!c_mark_addressable (op0))
3353             return error_mark_node;
3354           return build_binary_op (location, PLUS_EXPR,
3355                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3356                                    ? array_to_pointer_conversion (op0)
3357                                    : op0),
3358                                   TREE_OPERAND (arg, 1), 1);
3359         }
3360
3361       /* Anything not already handled and not a true memory reference
3362          or a non-lvalue array is an error.  */
3363       else if (typecode != FUNCTION_TYPE && !flag
3364                && !lvalue_or_else (arg, lv_addressof))
3365         return error_mark_node;
3366
3367       /* Move address operations inside C_MAYBE_CONST_EXPR to simplify
3368          folding later.  */
3369       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3370         {
3371           tree inner = build_unary_op (location, code,
3372                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3373           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3374                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3375           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3376           C_MAYBE_CONST_EXPR_NON_CONST (ret)
3377             = C_MAYBE_CONST_EXPR_NON_CONST (arg);
3378           goto return_build_unary_op;
3379         }
3380
3381       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3382       argtype = TREE_TYPE (arg);
3383
3384       /* If the lvalue is const or volatile, merge that into the type
3385          to which the address will point.  Note that you can't get a
3386          restricted pointer by taking the address of something, so we
3387          only have to deal with `const' and `volatile' here.  */
3388       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3389           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3390           argtype = c_build_type_variant (argtype,
3391                                           TREE_READONLY (arg),
3392                                           TREE_THIS_VOLATILE (arg));
3393
3394       if (!c_mark_addressable (arg))
3395         return error_mark_node;
3396
3397       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3398                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3399
3400       argtype = build_pointer_type (argtype);
3401
3402       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3403          when we have proper support for integer constant expressions.  */
3404       val = get_base_address (arg);
3405       if (val && TREE_CODE (val) == INDIRECT_REF
3406           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3407         {
3408           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3409
3410           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3411           ret = fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3412           goto return_build_unary_op;
3413         }
3414
3415       val = build1 (ADDR_EXPR, argtype, arg);
3416
3417       ret = val;
3418       goto return_build_unary_op;
3419
3420     default:
3421       gcc_unreachable ();
3422     }
3423
3424   if (argtype == 0)
3425     argtype = TREE_TYPE (arg);
3426   if (TREE_CODE (arg) == INTEGER_CST)
3427     ret = (require_constant_value
3428            ? fold_build1_initializer (code, argtype, arg)
3429            : fold_build1 (code, argtype, arg));
3430   else
3431     ret = build1 (code, argtype, arg);
3432  return_build_unary_op:
3433   gcc_assert (ret != error_mark_node);
3434   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret)
3435       && !(TREE_CODE (xarg) == INTEGER_CST && !TREE_OVERFLOW (xarg)))
3436     ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
3437   else if (TREE_CODE (ret) != INTEGER_CST && int_operands)
3438     ret = note_integer_operands (ret);
3439   if (eptype)
3440     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3441   protected_set_expr_location (ret, location);
3442   return ret;
3443 }
3444
3445 /* Return nonzero if REF is an lvalue valid for this language.
3446    Lvalues can be assigned, unless their type has TYPE_READONLY.
3447    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3448
3449 static int
3450 lvalue_p (const_tree ref)
3451 {
3452   const enum tree_code code = TREE_CODE (ref);
3453
3454   switch (code)
3455     {
3456     case REALPART_EXPR:
3457     case IMAGPART_EXPR:
3458     case COMPONENT_REF:
3459       return lvalue_p (TREE_OPERAND (ref, 0));
3460
3461     case C_MAYBE_CONST_EXPR:
3462       return lvalue_p (TREE_OPERAND (ref, 1));
3463
3464     case COMPOUND_LITERAL_EXPR:
3465     case STRING_CST:
3466       return 1;
3467
3468     case INDIRECT_REF:
3469     case ARRAY_REF:
3470     case VAR_DECL:
3471     case PARM_DECL:
3472     case RESULT_DECL:
3473     case ERROR_MARK:
3474       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3475               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3476
3477     case BIND_EXPR:
3478       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3479
3480     default:
3481       return 0;
3482     }
3483 }
3484 \f
3485 /* Give an error for storing in something that is 'const'.  */
3486
3487 static void
3488 readonly_error (tree arg, enum lvalue_use use)
3489 {
3490   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3491               || use == lv_asm);
3492   /* Using this macro rather than (for example) arrays of messages
3493      ensures that all the format strings are checked at compile
3494      time.  */
3495 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3496                                    : (use == lv_increment ? (I)         \
3497                                    : (use == lv_decrement ? (D) : (AS))))
3498   if (TREE_CODE (arg) == COMPONENT_REF)
3499     {
3500       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3501         readonly_error (TREE_OPERAND (arg, 0), use);
3502       else
3503         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3504                              G_("increment of read-only member %qD"),
3505                              G_("decrement of read-only member %qD"),
3506                              G_("read-only member %qD used as %<asm%> output")),
3507                TREE_OPERAND (arg, 1));
3508     }
3509   else if (TREE_CODE (arg) == VAR_DECL)
3510     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3511                          G_("increment of read-only variable %qD"),
3512                          G_("decrement of read-only variable %qD"),
3513                          G_("read-only variable %qD used as %<asm%> output")),
3514            arg);
3515   else
3516     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3517                          G_("increment of read-only location %qE"),
3518                          G_("decrement of read-only location %qE"),
3519                          G_("read-only location %qE used as %<asm%> output")),
3520            arg);
3521 }
3522
3523
3524 /* Return nonzero if REF is an lvalue valid for this language;
3525    otherwise, print an error message and return zero.  USE says
3526    how the lvalue is being used and so selects the error message.  */
3527
3528 static int
3529 lvalue_or_else (const_tree ref, enum lvalue_use use)
3530 {
3531   int win = lvalue_p (ref);
3532
3533   if (!win)
3534     lvalue_error (use);
3535
3536   return win;
3537 }
3538 \f
3539 /* Mark EXP saying that we need to be able to take the
3540    address of it; it should not be allocated in a register.
3541    Returns true if successful.  */
3542
3543 bool
3544 c_mark_addressable (tree exp)
3545 {
3546   tree x = exp;
3547
3548   while (1)
3549     switch (TREE_CODE (x))
3550       {
3551       case COMPONENT_REF:
3552         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3553           {
3554             error
3555               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3556             return false;
3557           }
3558
3559         /* ... fall through ...  */
3560
3561       case ADDR_EXPR:
3562       case ARRAY_REF:
3563       case REALPART_EXPR:
3564       case IMAGPART_EXPR:
3565         x = TREE_OPERAND (x, 0);
3566         break;
3567
3568       case COMPOUND_LITERAL_EXPR:
3569       case CONSTRUCTOR:
3570         TREE_ADDRESSABLE (x) = 1;
3571         return true;
3572
3573       case VAR_DECL:
3574       case CONST_DECL:
3575       case PARM_DECL:
3576       case RESULT_DECL:
3577         if (C_DECL_REGISTER (x)
3578             && DECL_NONLOCAL (x))
3579           {
3580             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3581               {
3582                 error
3583                   ("global register variable %qD used in nested function", x);
3584                 return false;
3585               }
3586             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3587           }
3588         else if (C_DECL_REGISTER (x))
3589           {
3590             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3591               error ("address of global register variable %qD requested", x);
3592             else
3593               error ("address of register variable %qD requested", x);
3594             return false;
3595           }
3596
3597         /* drops in */
3598       case FUNCTION_DECL:
3599         TREE_ADDRESSABLE (x) = 1;
3600         /* drops out */
3601       default:
3602         return true;
3603     }
3604 }
3605 \f
3606 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  If
3607    IFEXP_BCP then the condition is a call to __builtin_constant_p, and
3608    if folded to an integer constant then the unselected half may
3609    contain arbitrary operations not normally permitted in constant
3610    expressions.  */
3611
3612 tree
3613 build_conditional_expr (tree ifexp, bool ifexp_bcp, tree op1, tree op2)
3614 {
3615   tree type1;
3616   tree type2;
3617   enum tree_code code1;
3618   enum tree_code code2;
3619   tree result_type = NULL;
3620   tree ep_result_type = NULL;
3621   tree orig_op1 = op1, orig_op2 = op2;
3622   bool int_const, op1_int_operands, op2_int_operands, int_operands;
3623   bool ifexp_int_operands;
3624   tree ret;
3625   bool objc_ok;
3626
3627   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
3628   if (op1_int_operands)
3629     op1 = remove_c_maybe_const_expr (op1);
3630   op2_int_operands = EXPR_INT_CONST_OPERANDS (orig_op2);
3631   if (op2_int_operands)
3632     op2 = remove_c_maybe_const_expr (op2);
3633   ifexp_int_operands = EXPR_INT_CONST_OPERANDS (ifexp);
3634   if (ifexp_int_operands)
3635     ifexp = remove_c_maybe_const_expr (ifexp);
3636
3637   /* Promote both alternatives.  */
3638
3639   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3640     op1 = default_conversion (op1);
3641   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3642     op2 = default_conversion (op2);
3643
3644   if (TREE_CODE (ifexp) == ERROR_MARK
3645       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3646       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3647     return error_mark_node;
3648
3649   type1 = TREE_TYPE (op1);
3650   code1 = TREE_CODE (type1);
3651   type2 = TREE_TYPE (op2);
3652   code2 = TREE_CODE (type2);
3653
3654   /* C90 does not permit non-lvalue arrays in conditional expressions.
3655      In C99 they will be pointers by now.  */
3656   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3657     {
3658       error ("non-lvalue array in conditional expression");
3659       return error_mark_node;
3660     }
3661
3662   objc_ok = objc_compare_types (type1, type2, -3, NULL_TREE);
3663
3664   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
3665        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3666       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
3667           || code1 == COMPLEX_TYPE)
3668       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3669           || code2 == COMPLEX_TYPE))
3670     {
3671       ep_result_type = c_common_type (type1, type2);
3672       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
3673         {
3674           op1 = TREE_OPERAND (op1, 0);
3675           type1 = TREE_TYPE (op1);
3676           gcc_assert (TREE_CODE (type1) == code1);
3677         }
3678       if (TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3679         {
3680           op2 = TREE_OPERAND (op2, 0);
3681           type2 = TREE_TYPE (op2);
3682           gcc_assert (TREE_CODE (type2) == code2);
3683         }
3684     }
3685
3686   /* Quickly detect the usual case where op1 and op2 have the same type
3687      after promotion.  */
3688   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3689     {
3690       if (type1 == type2)
3691         result_type = type1;
3692       else
3693         result_type = TYPE_MAIN_VARIANT (type1);
3694     }
3695   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3696             || code1 == COMPLEX_TYPE)
3697            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3698                || code2 == COMPLEX_TYPE))
3699     {
3700       result_type = c_common_type (type1, type2);
3701
3702       /* If -Wsign-compare, warn here if type1 and type2 have
3703          different signedness.  We'll promote the signed to unsigned
3704          and later code won't know it used to be different.
3705          Do this check on the original types, so that explicit casts
3706          will be considered, but default promotions won't.  */
3707       if (!skip_evaluation)
3708         {
3709           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3710           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3711
3712           if (unsigned_op1 ^ unsigned_op2)
3713             {
3714               bool ovf;
3715
3716               /* Do not warn if the result type is signed, since the
3717                  signed type will only be chosen if it can represent
3718                  all the values of the unsigned type.  */
3719               if (!TYPE_UNSIGNED (result_type))
3720                 /* OK */;
3721               else
3722                 {
3723                   bool op1_maybe_const = true;
3724                   bool op2_maybe_const = true;
3725
3726                   /* Do not warn if the signed quantity is an
3727                      unsuffixed integer literal (or some static
3728                      constant expression involving such literals) and
3729                      it is non-negative.  This warning requires the
3730                      operands to be folded for best results, so do
3731                      that folding in this case even without
3732                      warn_sign_compare to avoid warning options
3733                      possibly affecting code generation.  */
3734                   op1 = c_fully_fold (op1, require_constant_value,
3735                                       &op1_maybe_const);
3736                   op2 = c_fully_fold (op2, require_constant_value,
3737                                       &op2_maybe_const);
3738
3739                   if (warn_sign_compare)
3740                     {
3741                       if ((unsigned_op2
3742                            && tree_expr_nonnegative_warnv_p (op1, &ovf))
3743                           || (unsigned_op1
3744                               && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3745                         /* OK */;
3746                       else
3747                         warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3748                     }
3749                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
3750                     {
3751                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
3752                                     NULL, op1);
3753                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
3754                     }
3755                   if (!op2_maybe_const || TREE_CODE (op2) != INTEGER_CST)
3756                     {
3757                       op2 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op2),
3758                                     NULL, op2);
3759                       C_MAYBE_CONST_EXPR_NON_CONST (op2) = !op2_maybe_const;
3760                     }
3761                 }
3762             }
3763         }
3764     }
3765   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3766     {
3767       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3768         pedwarn (input_location, OPT_pedantic,
3769                  "ISO C forbids conditional expr with only one void side");
3770       result_type = void_type_node;
3771     }
3772   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3773     {
3774       if (comp_target_types (type1, type2))
3775         result_type = common_pointer_type (type1, type2);
3776       else if (null_pointer_constant_p (orig_op1))
3777         result_type = qualify_type (type2, type1);
3778       else if (null_pointer_constant_p (orig_op2))
3779         result_type = qualify_type (type1, type2);
3780       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3781         {
3782           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3783             pedwarn (input_location, OPT_pedantic,
3784                      "ISO C forbids conditional expr between "
3785                      "%<void *%> and function pointer");
3786           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3787                                                           TREE_TYPE (type2)));
3788         }
3789       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3790         {
3791           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3792             pedwarn (input_location, OPT_pedantic,
3793                      "ISO C forbids conditional expr between "
3794                      "%<void *%> and function pointer");
3795           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3796                                                           TREE_TYPE (type1)));
3797         }
3798       else
3799         {
3800           if (!objc_ok)
3801             pedwarn (input_location, 0,
3802                      "pointer type mismatch in conditional expression");
3803           result_type = build_pointer_type (void_type_node);
3804         }
3805     }
3806   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3807     {
3808       if (!null_pointer_constant_p (orig_op2))
3809         pedwarn (input_location, 0,
3810                  "pointer/integer type mismatch in conditional expression");
3811       else
3812         {
3813           op2 = null_pointer_node;
3814         }
3815       result_type = type1;
3816     }
3817   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3818     {
3819       if (!null_pointer_constant_p (orig_op1))
3820         pedwarn (input_location, 0,
3821                  "pointer/integer type mismatch in conditional expression");
3822       else
3823         {
3824           op1 = null_pointer_node;
3825         }
3826       result_type = type2;
3827     }
3828
3829   if (!result_type)
3830     {
3831       if (flag_cond_mismatch)
3832         result_type = void_type_node;
3833       else
3834         {
3835           error ("type mismatch in conditional expression");
3836           return error_mark_node;
3837         }
3838     }
3839
3840   /* Merge const and volatile flags of the incoming types.  */
3841   result_type
3842     = build_type_variant (result_type,
3843                           TREE_READONLY (op1) || TREE_READONLY (op2),
3844                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3845
3846   if (result_type != TREE_TYPE (op1))
3847     op1 = convert_and_check (result_type, op1);
3848   if (result_type != TREE_TYPE (op2))
3849     op2 = convert_and_check (result_type, op2);
3850
3851   if (ifexp_bcp && ifexp == truthvalue_true_node)
3852     {
3853       op2_int_operands = true;
3854       op1 = c_fully_fold (op1, require_constant_value, NULL);
3855     }
3856   if (ifexp_bcp && ifexp == truthvalue_false_node)
3857     {
3858       op1_int_operands = true;
3859       op2 = c_fully_fold (op2, require_constant_value, NULL);
3860     }
3861   int_const = int_operands = (ifexp_int_operands
3862                               && op1_int_operands
3863                               && op2_int_operands);
3864   if (int_operands)
3865     {
3866       int_const = ((ifexp == truthvalue_true_node
3867                     && TREE_CODE (orig_op1) == INTEGER_CST
3868                     && !TREE_OVERFLOW (orig_op1))
3869                    || (ifexp == truthvalue_false_node
3870                        && TREE_CODE (orig_op2) == INTEGER_CST
3871                        && !TREE_OVERFLOW (orig_op2)));
3872     }
3873   if (int_const || (ifexp_bcp && TREE_CODE (ifexp) == INTEGER_CST))
3874     ret = fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3875   else
3876     {
3877       ret = build3 (COND_EXPR, result_type, ifexp, op1, op2);
3878       if (int_operands)
3879         ret = note_integer_operands (ret);
3880     }
3881   if (ep_result_type)
3882     ret = build1 (EXCESS_PRECISION_EXPR, ep_result_type, ret);
3883
3884   return ret;
3885 }
3886 \f
3887 /* Return a compound expression that performs two expressions and
3888    returns the value of the second of them.  */
3889
3890 tree
3891 build_compound_expr (tree expr1, tree expr2)
3892 {
3893   bool expr1_int_operands, expr2_int_operands;
3894   tree eptype = NULL_TREE;
3895   tree ret;
3896
3897   expr1_int_operands = EXPR_INT_CONST_OPERANDS (expr1);
3898   if (expr1_int_operands)
3899     expr1 = remove_c_maybe_const_expr (expr1);
3900   expr2_int_operands = EXPR_INT_CONST_OPERANDS (expr2);
3901   if (expr2_int_operands)
3902     expr2 = remove_c_maybe_const_expr (expr2);
3903
3904   if (TREE_CODE (expr1) == EXCESS_PRECISION_EXPR)
3905     expr1 = TREE_OPERAND (expr1, 0);
3906   if (TREE_CODE (expr2) == EXCESS_PRECISION_EXPR)
3907     {
3908       eptype = TREE_TYPE (expr2);
3909       expr2 = TREE_OPERAND (expr2, 0);
3910     }
3911
3912   if (!TREE_SIDE_EFFECTS (expr1))
3913     {
3914       /* The left-hand operand of a comma expression is like an expression
3915          statement: with -Wunused, we should warn if it doesn't have
3916          any side-effects, unless it was explicitly cast to (void).  */
3917       if (warn_unused_value)
3918         {
3919           if (VOID_TYPE_P (TREE_TYPE (expr1))
3920               && CONVERT_EXPR_P (expr1))
3921             ; /* (void) a, b */
3922           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3923                    && TREE_CODE (expr1) == COMPOUND_EXPR
3924                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
3925             ; /* (void) a, (void) b, c */
3926           else
3927             warning (OPT_Wunused_value,
3928                      "left-hand operand of comma expression has no effect");
3929         }
3930     }
3931
3932   /* With -Wunused, we should also warn if the left-hand operand does have
3933      side-effects, but computes a value which is not used.  For example, in
3934      `foo() + bar(), baz()' the result of the `+' operator is not used,
3935      so we should issue a warning.  */
3936   else if (warn_unused_value)
3937     warn_if_unused_value (expr1, input_location);
3938
3939   if (expr2 == error_mark_node)
3940     return error_mark_node;
3941
3942   ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3943
3944   if (flag_isoc99
3945       && expr1_int_operands
3946       && expr2_int_operands)
3947     ret = note_integer_operands (ret);
3948
3949   if (eptype)
3950     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3951
3952   return ret;
3953 }
3954
3955 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3956
3957 tree
3958 build_c_cast (tree type, tree expr)
3959 {
3960   tree value;
3961
3962   if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
3963     expr = TREE_OPERAND (expr, 0);
3964
3965   value = expr;
3966
3967   if (type == error_mark_node || expr == error_mark_node)
3968     return error_mark_node;
3969
3970   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3971      only in <protocol> qualifications.  But when constructing cast expressions,
3972      the protocols do matter and must be kept around.  */
3973   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3974     return build1 (NOP_EXPR, type, expr);
3975
3976   type = TYPE_MAIN_VARIANT (type);
3977
3978   if (TREE_CODE (type) == ARRAY_TYPE)
3979     {
3980       error ("cast specifies array type");
3981       return error_mark_node;
3982     }
3983
3984   if (TREE_CODE (type) == FUNCTION_TYPE)
3985     {
3986       error ("cast specifies function type");
3987       return error_mark_node;
3988     }
3989
3990   if (!VOID_TYPE_P (type))
3991     {
3992       value = require_complete_type (value);
3993       if (value == error_mark_node)
3994         return error_mark_node;
3995     }
3996
3997   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3998     {
3999       if (TREE_CODE (type) == RECORD_TYPE
4000           || TREE_CODE (type) == UNION_TYPE)
4001         pedwarn (input_location, OPT_pedantic,
4002                  "ISO C forbids casting nonscalar to the same type");
4003     }
4004   else if (TREE_CODE (type) == UNION_TYPE)
4005     {
4006       tree field;
4007
4008       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4009         if (TREE_TYPE (field) != error_mark_node
4010             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
4011                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
4012           break;
4013
4014       if (field)
4015         {
4016           tree t;
4017
4018           pedwarn (input_location, OPT_pedantic,
4019                    "ISO C forbids casts to union type");
4020           t = digest_init (type,
4021                            build_constructor_single (type, field, value),
4022                            false, true, 0);
4023           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4024           return t;
4025         }
4026       error ("cast to union type from type not present in union");
4027       return error_mark_node;
4028     }
4029   else
4030     {
4031       tree otype, ovalue;
4032
4033       if (type == void_type_node)
4034         return build1 (CONVERT_EXPR, type, value);
4035
4036       otype = TREE_TYPE (value);
4037
4038       /* Optionally warn about potentially worrisome casts.  */
4039
4040       if (warn_cast_qual
4041           && TREE_CODE (type) == POINTER_TYPE
4042           && TREE_CODE (otype) == POINTER_TYPE)
4043         {
4044           tree in_type = type;
4045           tree in_otype = otype;
4046           int added = 0;
4047           int discarded = 0;
4048
4049           /* Check that the qualifiers on IN_TYPE are a superset of
4050              the qualifiers of IN_OTYPE.  The outermost level of
4051              POINTER_TYPE nodes is uninteresting and we stop as soon
4052              as we hit a non-POINTER_TYPE node on either type.  */
4053           do
4054             {
4055               in_otype = TREE_TYPE (in_otype);
4056               in_type = TREE_TYPE (in_type);
4057
4058               /* GNU C allows cv-qualified function types.  'const'
4059                  means the function is very pure, 'volatile' means it
4060                  can't return.  We need to warn when such qualifiers
4061                  are added, not when they're taken away.  */
4062               if (TREE_CODE (in_otype) == FUNCTION_TYPE
4063                   && TREE_CODE (in_type) == FUNCTION_TYPE)
4064                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
4065               else
4066                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
4067             }
4068           while (TREE_CODE (in_type) == POINTER_TYPE
4069                  && TREE_CODE (in_otype) == POINTER_TYPE);
4070
4071           if (added)
4072             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
4073
4074           if (discarded)
4075             /* There are qualifiers present in IN_OTYPE that are not
4076                present in IN_TYPE.  */
4077             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
4078         }
4079
4080       /* Warn about possible alignment problems.  */
4081       if (STRICT_ALIGNMENT
4082           && TREE_CODE (type) == POINTER_TYPE
4083           && TREE_CODE (otype) == POINTER_TYPE
4084           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4085           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4086           /* Don't warn about opaque types, where the actual alignment
4087              restriction is unknown.  */
4088           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4089                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4090                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4091           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4092         warning (OPT_Wcast_align,
4093                  "cast increases required alignment of target type");
4094
4095       if (TREE_CODE (type) == INTEGER_TYPE
4096           && TREE_CODE (otype) == POINTER_TYPE
4097           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4098       /* Unlike conversion of integers to pointers, where the
4099          warning is disabled for converting constants because
4100          of cases such as SIG_*, warn about converting constant
4101          pointers to integers. In some cases it may cause unwanted
4102          sign extension, and a warning is appropriate.  */
4103         warning (OPT_Wpointer_to_int_cast,
4104                  "cast from pointer to integer of different size");
4105
4106       if (TREE_CODE (value) == CALL_EXPR
4107           && TREE_CODE (type) != TREE_CODE (otype))
4108         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
4109                  "to non-matching type %qT", otype, type);
4110
4111       if (TREE_CODE (type) == POINTER_TYPE
4112           && TREE_CODE (otype) == INTEGER_TYPE
4113           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4114           /* Don't warn about converting any constant.  */
4115           && !TREE_CONSTANT (value))
4116         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4117                  "of different size");
4118
4119       if (warn_strict_aliasing <= 2)
4120         strict_aliasing_warning (otype, type, expr);
4121
4122       /* If pedantic, warn for conversions between function and object
4123          pointer types, except for converting a null pointer constant
4124          to function pointer type.  */
4125       if (pedantic
4126           && TREE_CODE (type) == POINTER_TYPE
4127           && TREE_CODE (otype) == POINTER_TYPE
4128           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4129           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4130         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
4131                  "conversion of function pointer to object pointer type");
4132
4133       if (pedantic
4134           && TREE_CODE (type) == POINTER_TYPE
4135           && TREE_CODE (otype) == POINTER_TYPE
4136           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4137           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4138           && !null_pointer_constant_p (value))
4139         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
4140                  "conversion of object pointer to function pointer type");
4141
4142       ovalue = value;
4143       value = convert (type, value);
4144
4145       /* Ignore any integer overflow caused by the cast.  */
4146       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4147         {
4148           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4149             {
4150               if (!TREE_OVERFLOW (value))
4151                 {
4152                   /* Avoid clobbering a shared constant.  */
4153                   value = copy_node (value);
4154                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4155                 }
4156             }
4157           else if (TREE_OVERFLOW (value))
4158             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4159             value = build_int_cst_wide (TREE_TYPE (value),
4160                                         TREE_INT_CST_LOW (value),
4161                                         TREE_INT_CST_HIGH (value));
4162         }
4163     }
4164
4165   /* Don't let a cast be an lvalue.  */
4166   if (value == expr)
4167     value = non_lvalue (value);
4168
4169   /* Don't allow the results of casting to floating-point or complex
4170      types be confused with actual constants, or casts involving
4171      integer and pointer types other than direct integer-to-integer
4172      and integer-to-pointer be confused with integer constant
4173      expressions and null pointer constants.  */
4174   if (TREE_CODE (value) == REAL_CST
4175       || TREE_CODE (value) == COMPLEX_CST
4176       || (TREE_CODE (value) == INTEGER_CST
4177           && !((TREE_CODE (expr) == INTEGER_CST
4178                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4179                || TREE_CODE (expr) == REAL_CST
4180                || TREE_CODE (expr) == COMPLEX_CST)))
4181       value = build1 (NOP_EXPR, type, value);
4182
4183   return value;
4184 }
4185
4186 /* Interpret a cast of expression EXPR to type TYPE.  */
4187 tree
4188 c_cast_expr (struct c_type_name *type_name, tree expr)
4189 {
4190   tree type;
4191   tree type_expr = NULL_TREE;
4192   bool type_expr_const = true;
4193   tree ret;
4194   int saved_wsp = warn_strict_prototypes;
4195
4196   /* This avoids warnings about unprototyped casts on
4197      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4198   if (TREE_CODE (expr) == INTEGER_CST)
4199     warn_strict_prototypes = 0;
4200   type = groktypename (type_name, &type_expr, &type_expr_const);
4201   warn_strict_prototypes = saved_wsp;
4202
4203   ret = build_c_cast (type, expr);
4204   if (type_expr)
4205     {
4206       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4207       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4208     }
4209   return ret;
4210 }
4211 \f
4212 /* Build an assignment expression of lvalue LHS from value RHS.
4213    MODIFYCODE is the code for a binary operator that we use
4214    to combine the old value of LHS with RHS to get the new value.
4215    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4216
4217    LOCATION is the location of the MODIFYCODE operator.  */
4218
4219 tree
4220 build_modify_expr (location_t location,
4221                    tree lhs, enum tree_code modifycode, tree rhs)
4222 {
4223   tree result;
4224   tree newrhs;
4225   tree rhs_semantic_type = NULL_TREE;
4226   tree lhstype = TREE_TYPE (lhs);
4227   tree olhstype = lhstype;
4228   bool npc;
4229
4230   /* Types that aren't fully specified cannot be used in assignments.  */
4231   lhs = require_complete_type (lhs);
4232
4233   /* Avoid duplicate error messages from operands that had errors.  */
4234   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4235     return error_mark_node;
4236
4237   if (!lvalue_or_else (lhs, lv_assign))
4238     return error_mark_node;
4239
4240   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4241     {
4242       rhs_semantic_type = TREE_TYPE (rhs);
4243       rhs = TREE_OPERAND (rhs, 0);
4244     }
4245
4246   newrhs = rhs;
4247
4248   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4249     {
4250       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4251                                       modifycode, rhs);
4252       if (inner == error_mark_node)
4253         return error_mark_node;
4254       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4255                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4256       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4257       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4258       protected_set_expr_location (result, location);
4259       return result;
4260     }
4261
4262   /* If a binary op has been requested, combine the old LHS value with the RHS
4263      producing the value we should actually store into the LHS.  */
4264
4265   if (modifycode != NOP_EXPR)
4266     {
4267       lhs = c_fully_fold (lhs, false, NULL);
4268       lhs = stabilize_reference (lhs);
4269       newrhs = build_binary_op (location,
4270                                 modifycode, lhs, rhs, 1);
4271     }
4272
4273   /* Give an error for storing in something that is 'const'.  */
4274
4275   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
4276       || ((TREE_CODE (lhstype) == RECORD_TYPE
4277            || TREE_CODE (lhstype) == UNION_TYPE)
4278           && C_TYPE_FIELDS_READONLY (lhstype)))
4279     {
4280       readonly_error (lhs, lv_assign);
4281       return error_mark_node;
4282     }
4283
4284   /* If storing into a structure or union member,
4285      it has probably been given type `int'.
4286      Compute the type that would go with
4287      the actual amount of storage the member occupies.  */
4288
4289   if (TREE_CODE (lhs) == COMPONENT_REF
4290       && (TREE_CODE (lhstype) == INTEGER_TYPE
4291           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4292           || TREE_CODE (lhstype) == REAL_TYPE
4293           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4294     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4295
4296   /* If storing in a field that is in actuality a short or narrower than one,
4297      we must store in the field in its actual type.  */
4298
4299   if (lhstype != TREE_TYPE (lhs))
4300     {
4301       lhs = copy_node (lhs);
4302       TREE_TYPE (lhs) = lhstype;
4303     }
4304
4305   /* Convert new value to destination type.  Fold it first, then
4306      restore any excess precision information, for the sake of
4307      conversion warnings.  */
4308
4309   npc = null_pointer_constant_p (newrhs);
4310   newrhs = c_fully_fold (newrhs, false, NULL);
4311   if (rhs_semantic_type)
4312     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4313   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign, npc,
4314                                    NULL_TREE, NULL_TREE, 0);
4315   if (TREE_CODE (newrhs) == ERROR_MARK)
4316     return error_mark_node;
4317
4318   /* Emit ObjC write barrier, if necessary.  */
4319   if (c_dialect_objc () && flag_objc_gc)
4320     {
4321       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4322       if (result)
4323         {
4324           protected_set_expr_location (result, location);
4325           return result;
4326         }
4327     }
4328
4329   /* Scan operands.  */
4330
4331   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4332   TREE_SIDE_EFFECTS (result) = 1;
4333   protected_set_expr_location (result, location);
4334
4335   /* If we got the LHS in a different type for storing in,
4336      convert the result back to the nominal type of LHS
4337      so that the value we return always has the same type
4338      as the LHS argument.  */
4339
4340   if (olhstype == TREE_TYPE (result))
4341     return result;
4342
4343   result = convert_for_assignment (olhstype, result, ic_assign, false,
4344                                    NULL_TREE, NULL_TREE, 0);
4345   protected_set_expr_location (result, location);
4346   return result;
4347 }
4348 \f
4349 /* Convert value RHS to type TYPE as preparation for an assignment
4350    to an lvalue of type TYPE.  NULL_POINTER_CONSTANT says whether RHS
4351    was a null pointer constant before any folding.
4352    The real work of conversion is done by `convert'.
4353    The purpose of this function is to generate error messages
4354    for assignments that are not allowed in C.
4355    ERRTYPE says whether it is argument passing, assignment,
4356    initialization or return.
4357
4358    FUNCTION is a tree for the function being called.
4359    PARMNUM is the number of the argument, for printing in error messages.  */
4360
4361 static tree
4362 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
4363                         bool null_pointer_constant,
4364                         tree fundecl, tree function, int parmnum)
4365 {
4366   enum tree_code codel = TREE_CODE (type);
4367   tree orig_rhs = rhs;
4368   tree rhstype;
4369   enum tree_code coder;
4370   tree rname = NULL_TREE;
4371   bool objc_ok = false;
4372
4373   if (errtype == ic_argpass)
4374     {
4375       tree selector;
4376       /* Change pointer to function to the function itself for
4377          diagnostics.  */
4378       if (TREE_CODE (function) == ADDR_EXPR
4379           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
4380         function = TREE_OPERAND (function, 0);
4381
4382       /* Handle an ObjC selector specially for diagnostics.  */
4383       selector = objc_message_selector ();
4384       rname = function;
4385       if (selector && parmnum > 2)
4386         {
4387           rname = selector;
4388           parmnum -= 2;
4389         }
4390     }
4391
4392   /* This macro is used to emit diagnostics to ensure that all format
4393      strings are complete sentences, visible to gettext and checked at
4394      compile time.  */
4395 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4396   do {                                                                   \
4397     switch (errtype)                                                     \
4398       {                                                                  \
4399       case ic_argpass:                                                   \
4400         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4401           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4402                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4403                   "expected %qT but argument is of type %qT",            \
4404                   type, rhstype);                                        \
4405         break;                                                           \
4406       case ic_assign:                                                    \
4407         pedwarn (LOCATION, OPT, AS);                                     \
4408         break;                                                           \
4409       case ic_init:                                                      \
4410         pedwarn (LOCATION, OPT, IN);                                     \
4411         break;                                                           \
4412       case ic_return:                                                    \
4413         pedwarn (LOCATION, OPT, RE);                                     \
4414         break;                                                           \
4415       default:                                                           \
4416         gcc_unreachable ();                                              \
4417       }                                                                  \
4418   } while (0)
4419
4420   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4421     rhs = TREE_OPERAND (rhs, 0);
4422
4423   rhstype = TREE_TYPE (rhs);
4424   coder = TREE_CODE (rhstype);
4425
4426   if (coder == ERROR_MARK)
4427     return error_mark_node;
4428
4429   if (c_dialect_objc ())
4430     {
4431       int parmno;
4432
4433       switch (errtype)
4434         {
4435         case ic_return:
4436           parmno = 0;
4437           break;
4438
4439         case ic_assign:
4440           parmno = -1;
4441           break;
4442
4443         case ic_init:
4444           parmno = -2;
4445           break;
4446
4447         default:
4448           parmno = parmnum;
4449           break;
4450         }
4451
4452       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4453     }
4454
4455   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4456     return rhs;
4457
4458   if (coder == VOID_TYPE)
4459     {
4460       /* Except for passing an argument to an unprototyped function,
4461          this is a constraint violation.  When passing an argument to
4462          an unprototyped function, it is compile-time undefined;
4463          making it a constraint in that case was rejected in
4464          DR#252.  */
4465       error ("void value not ignored as it ought to be");
4466       return error_mark_node;
4467     }
4468   rhs = require_complete_type (rhs);
4469   if (rhs == error_mark_node)
4470     return error_mark_node;
4471   /* A type converts to a reference to it.
4472      This code doesn't fully support references, it's just for the
4473      special case of va_start and va_copy.  */
4474   if (codel == REFERENCE_TYPE
4475       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4476     {
4477       if (!lvalue_p (rhs))
4478         {
4479           error ("cannot pass rvalue to reference parameter");
4480           return error_mark_node;
4481         }
4482       if (!c_mark_addressable (rhs))
4483         return error_mark_node;
4484       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4485
4486       /* We already know that these two types are compatible, but they
4487          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4488          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4489          likely to be va_list, a typedef to __builtin_va_list, which
4490          is different enough that it will cause problems later.  */
4491       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4492         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4493
4494       rhs = build1 (NOP_EXPR, type, rhs);
4495       return rhs;
4496     }
4497   /* Some types can interconvert without explicit casts.  */
4498   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4499            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4500     return convert (type, rhs);
4501   /* Arithmetic types all interconvert, and enum is treated like int.  */
4502   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4503             || codel == FIXED_POINT_TYPE
4504             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4505             || codel == BOOLEAN_TYPE)
4506            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4507                || coder == FIXED_POINT_TYPE
4508                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4509                || coder == BOOLEAN_TYPE))
4510     {
4511       tree ret;
4512       bool save = in_late_binary_op;
4513       if (codel == BOOLEAN_TYPE)
4514         in_late_binary_op = true;
4515       ret = convert_and_check (type, orig_rhs);
4516       if (codel == BOOLEAN_TYPE)
4517         in_late_binary_op = save;
4518       return ret;
4519     }
4520
4521   /* Aggregates in different TUs might need conversion.  */
4522   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4523       && codel == coder
4524       && comptypes (type, rhstype))
4525     return convert_and_check (type, rhs);
4526
4527   /* Conversion to a transparent union from its member types.
4528      This applies only to function arguments.  */
4529   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4530       && errtype == ic_argpass)
4531     {
4532       tree memb, marginal_memb = NULL_TREE;
4533
4534       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4535         {
4536           tree memb_type = TREE_TYPE (memb);
4537
4538           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4539                          TYPE_MAIN_VARIANT (rhstype)))
4540             break;
4541
4542           if (TREE_CODE (memb_type) != POINTER_TYPE)
4543             continue;
4544
4545           if (coder == POINTER_TYPE)
4546             {
4547               tree ttl = TREE_TYPE (memb_type);
4548               tree ttr = TREE_TYPE (rhstype);
4549
4550               /* Any non-function converts to a [const][volatile] void *
4551                  and vice versa; otherwise, targets must be the same.
4552                  Meanwhile, the lhs target must have all the qualifiers of
4553                  the rhs.  */
4554               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4555                   || comp_target_types (memb_type, rhstype))
4556                 {
4557                   /* If this type won't generate any warnings, use it.  */
4558                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4559                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4560                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4561                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4562                              == TYPE_QUALS (ttr))
4563                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4564                              == TYPE_QUALS (ttl))))
4565                     break;
4566
4567                   /* Keep looking for a better type, but remember this one.  */
4568                   if (!marginal_memb)
4569                     marginal_memb = memb;
4570                 }
4571             }
4572
4573           /* Can convert integer zero to any pointer type.  */
4574           if (null_pointer_constant)
4575             {
4576               rhs = null_pointer_node;
4577               break;
4578             }
4579         }
4580
4581       if (memb || marginal_memb)
4582         {
4583           if (!memb)
4584             {
4585               /* We have only a marginally acceptable member type;
4586                  it needs a warning.  */
4587               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4588               tree ttr = TREE_TYPE (rhstype);
4589
4590               /* Const and volatile mean something different for function
4591                  types, so the usual warnings are not appropriate.  */
4592               if (TREE_CODE (ttr) == FUNCTION_TYPE
4593                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4594                 {
4595                   /* Because const and volatile on functions are
4596                      restrictions that say the function will not do
4597                      certain things, it is okay to use a const or volatile
4598                      function where an ordinary one is wanted, but not
4599                      vice-versa.  */
4600                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4601                     WARN_FOR_ASSIGNMENT (input_location, 0,
4602                                          G_("passing argument %d of %qE "
4603                                             "makes qualified function "
4604                                             "pointer from unqualified"),
4605                                          G_("assignment makes qualified "
4606                                             "function pointer from "
4607                                             "unqualified"),
4608                                          G_("initialization makes qualified "
4609                                             "function pointer from "
4610                                             "unqualified"),
4611                                          G_("return makes qualified function "
4612                                             "pointer from unqualified"));
4613                 }
4614               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4615                 WARN_FOR_ASSIGNMENT (input_location, 0,
4616                                      G_("passing argument %d of %qE discards "
4617                                         "qualifiers from pointer target type"),
4618                                      G_("assignment discards qualifiers "
4619                                         "from pointer target type"),
4620                                      G_("initialization discards qualifiers "
4621                                         "from pointer target type"),
4622                                      G_("return discards qualifiers from "
4623                                         "pointer target type"));
4624
4625               memb = marginal_memb;
4626             }
4627
4628           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4629             pedwarn (input_location, OPT_pedantic,
4630                      "ISO C prohibits argument conversion to union type");
4631
4632           rhs = fold_convert (TREE_TYPE (memb), rhs);
4633           return build_constructor_single (type, memb, rhs);
4634         }
4635     }
4636
4637   /* Conversions among pointers */
4638   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4639            && (coder == codel))
4640     {
4641       tree ttl = TREE_TYPE (type);
4642       tree ttr = TREE_TYPE (rhstype);
4643       tree mvl = ttl;
4644       tree mvr = ttr;
4645       bool is_opaque_pointer;
4646       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4647
4648       if (TREE_CODE (mvl) != ARRAY_TYPE)
4649         mvl = TYPE_MAIN_VARIANT (mvl);
4650       if (TREE_CODE (mvr) != ARRAY_TYPE)
4651         mvr = TYPE_MAIN_VARIANT (mvr);
4652       /* Opaque pointers are treated like void pointers.  */
4653       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4654
4655       /* C++ does not allow the implicit conversion void* -> T*.  However,
4656          for the purpose of reducing the number of false positives, we
4657          tolerate the special case of
4658
4659                 int *p = NULL;
4660
4661          where NULL is typically defined in C to be '(void *) 0'.  */
4662       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4663         warning (OPT_Wc___compat, "request for implicit conversion from "
4664                  "%qT to %qT not permitted in C++", rhstype, type);
4665
4666       /* Check if the right-hand side has a format attribute but the
4667          left-hand side doesn't.  */
4668       if (warn_missing_format_attribute
4669           && check_missing_format_attribute (type, rhstype))
4670         {
4671           switch (errtype)
4672           {
4673           case ic_argpass:
4674             warning (OPT_Wmissing_format_attribute,
4675                      "argument %d of %qE might be "
4676                      "a candidate for a format attribute",
4677                      parmnum, rname);
4678             break;
4679           case ic_assign:
4680             warning (OPT_Wmissing_format_attribute,
4681                      "assignment left-hand side might be "
4682                      "a candidate for a format attribute");
4683             break;
4684           case ic_init:
4685             warning (OPT_Wmissing_format_attribute,
4686                      "initialization left-hand side might be "
4687                      "a candidate for a format attribute");
4688             break;
4689           case ic_return:
4690             warning (OPT_Wmissing_format_attribute,
4691                      "return type might be "
4692                      "a candidate for a format attribute");
4693             break;
4694           default:
4695             gcc_unreachable ();
4696           }
4697         }
4698
4699       /* Any non-function converts to a [const][volatile] void *
4700          and vice versa; otherwise, targets must be the same.
4701          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4702       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4703           || (target_cmp = comp_target_types (type, rhstype))
4704           || is_opaque_pointer
4705           || (c_common_unsigned_type (mvl)
4706               == c_common_unsigned_type (mvr)))
4707         {
4708           if (pedantic
4709               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4710                   ||
4711                   (VOID_TYPE_P (ttr)
4712                    && !null_pointer_constant
4713                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4714             WARN_FOR_ASSIGNMENT (input_location, OPT_pedantic,
4715                                  G_("ISO C forbids passing argument %d of "
4716                                     "%qE between function pointer "
4717                                     "and %<void *%>"),
4718                                  G_("ISO C forbids assignment between "
4719                                     "function pointer and %<void *%>"),
4720                                  G_("ISO C forbids initialization between "
4721                                     "function pointer and %<void *%>"),
4722                                  G_("ISO C forbids return between function "
4723                                     "pointer and %<void *%>"));
4724           /* Const and volatile mean something different for function types,
4725              so the usual warnings are not appropriate.  */
4726           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4727                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4728             {
4729               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4730                 {
4731                   /* Types differing only by the presence of the 'volatile'
4732                      qualifier are acceptable if the 'volatile' has been added
4733                      in by the Objective-C EH machinery.  */
4734                   if (!objc_type_quals_match (ttl, ttr))
4735                     WARN_FOR_ASSIGNMENT (input_location, 0,
4736                                          G_("passing argument %d of %qE discards "
4737                                             "qualifiers from pointer target type"),
4738                                          G_("assignment discards qualifiers "
4739                                             "from pointer target type"),
4740                                          G_("initialization discards qualifiers "
4741                                             "from pointer target type"),
4742                                          G_("return discards qualifiers from "
4743                                             "pointer target type"));
4744                 }
4745               /* If this is not a case of ignoring a mismatch in signedness,
4746                  no warning.  */
4747               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4748                        || target_cmp)
4749                 ;
4750               /* If there is a mismatch, do warn.  */
4751               else if (warn_pointer_sign)
4752                 WARN_FOR_ASSIGNMENT (input_location, OPT_Wpointer_sign,
4753                                      G_("pointer targets in passing argument "
4754                                         "%d of %qE differ in signedness"),
4755                                      G_("pointer targets in assignment "
4756                                         "differ in signedness"),
4757                                      G_("pointer targets in initialization "
4758                                         "differ in signedness"),
4759                                      G_("pointer targets in return differ "
4760                                         "in signedness"));
4761             }
4762           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4763                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4764             {
4765               /* Because const and volatile on functions are restrictions
4766                  that say the function will not do certain things,
4767                  it is okay to use a const or volatile function
4768                  where an ordinary one is wanted, but not vice-versa.  */
4769               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4770                 WARN_FOR_ASSIGNMENT (input_location, 0,
4771                                      G_("passing argument %d of %qE makes "
4772                                         "qualified function pointer "
4773                                         "from unqualified"),
4774                                      G_("assignment makes qualified function "
4775                                         "pointer from unqualified"),
4776                                      G_("initialization makes qualified "
4777                                         "function pointer from unqualified"),
4778                                      G_("return makes qualified function "
4779                                         "pointer from unqualified"));
4780             }
4781         }
4782       else
4783         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4784         if (!objc_ok)
4785           WARN_FOR_ASSIGNMENT (input_location, 0,
4786                                G_("passing argument %d of %qE from "
4787                                   "incompatible pointer type"),
4788                                G_("assignment from incompatible pointer type"),
4789                                G_("initialization from incompatible "
4790                                   "pointer type"),
4791                                G_("return from incompatible pointer type"));
4792
4793       return convert (type, rhs);
4794     }
4795   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4796     {
4797       /* ??? This should not be an error when inlining calls to
4798          unprototyped functions.  */
4799       error ("invalid use of non-lvalue array");
4800       return error_mark_node;
4801     }
4802   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4803     {
4804       /* An explicit constant 0 can convert to a pointer,
4805          or one that results from arithmetic, even including
4806          a cast to integer type.  */
4807       if (!null_pointer_constant)
4808         WARN_FOR_ASSIGNMENT (input_location, 0,
4809                              G_("passing argument %d of %qE makes "
4810                                 "pointer from integer without a cast"),
4811                              G_("assignment makes pointer from integer "
4812                                 "without a cast"),
4813                              G_("initialization makes pointer from "
4814                                 "integer without a cast"),
4815                              G_("return makes pointer from integer "
4816                                 "without a cast"));
4817
4818       return convert (type, rhs);
4819     }
4820   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4821     {
4822       WARN_FOR_ASSIGNMENT (input_location, 0,
4823                            G_("passing argument %d of %qE makes integer "
4824                               "from pointer without a cast"),
4825                            G_("assignment makes integer from pointer "
4826                               "without a cast"),
4827                            G_("initialization makes integer from pointer "
4828                               "without a cast"),
4829                            G_("return makes integer from pointer "
4830                               "without a cast"));
4831       return convert (type, rhs);
4832     }
4833   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4834     {
4835       tree ret;
4836       bool save = in_late_binary_op;
4837       in_late_binary_op = true;
4838       ret = convert (type, rhs);
4839       in_late_binary_op = save;
4840       return ret;
4841     }
4842
4843   switch (errtype)
4844     {
4845     case ic_argpass:
4846       error ("incompatible type for argument %d of %qE", parmnum, rname);
4847       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
4848               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
4849               "expected %qT but argument is of type %qT", type, rhstype);
4850       break;
4851     case ic_assign:
4852       error ("incompatible types when assigning to type %qT from type %qT",
4853              type, rhstype);
4854       break;
4855     case ic_init:
4856       error ("incompatible types when initializing type %qT using type %qT",
4857              type, rhstype);
4858       break;
4859     case ic_return:
4860       error ("incompatible types when returning type %qT but %qT was expected",
4861              rhstype, type);
4862       break;
4863     default:
4864       gcc_unreachable ();
4865     }
4866
4867   return error_mark_node;
4868 }
4869 \f
4870 /* If VALUE is a compound expr all of whose expressions are constant, then
4871    return its value.  Otherwise, return error_mark_node.
4872
4873    This is for handling COMPOUND_EXPRs as initializer elements
4874    which is allowed with a warning when -pedantic is specified.  */
4875
4876 static tree
4877 valid_compound_expr_initializer (tree value, tree endtype)
4878 {
4879   if (TREE_CODE (value) == COMPOUND_EXPR)
4880     {
4881       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4882           == error_mark_node)
4883         return error_mark_node;
4884       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4885                                               endtype);
4886     }
4887   else if (!initializer_constant_valid_p (value, endtype))
4888     return error_mark_node;
4889   else
4890     return value;
4891 }
4892 \f
4893 /* Perform appropriate conversions on the initial value of a variable,
4894    store it in the declaration DECL,
4895    and print any error messages that are appropriate.
4896    If the init is invalid, store an ERROR_MARK.  */
4897
4898 void
4899 store_init_value (tree decl, tree init)
4900 {
4901   tree value, type;
4902   bool npc = false;
4903
4904   /* If variable's type was invalidly declared, just ignore it.  */
4905
4906   type = TREE_TYPE (decl);
4907   if (TREE_CODE (type) == ERROR_MARK)
4908     return;
4909
4910   /* Digest the specified initializer into an expression.  */
4911
4912   if (init)
4913     npc = null_pointer_constant_p (init);
4914   value = digest_init (type, init, npc, true, TREE_STATIC (decl));
4915
4916   /* Store the expression if valid; else report error.  */
4917
4918   if (!in_system_header
4919       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4920     warning (OPT_Wtraditional, "traditional C rejects automatic "
4921              "aggregate initialization");
4922
4923   DECL_INITIAL (decl) = value;
4924
4925   /* ANSI wants warnings about out-of-range constant initializers.  */
4926   STRIP_TYPE_NOPS (value);
4927   if (TREE_STATIC (decl))
4928     constant_expression_warning (value);
4929
4930   /* Check if we need to set array size from compound literal size.  */
4931   if (TREE_CODE (type) == ARRAY_TYPE
4932       && TYPE_DOMAIN (type) == 0
4933       && value != error_mark_node)
4934     {
4935       tree inside_init = init;
4936
4937       STRIP_TYPE_NOPS (inside_init);
4938       inside_init = fold (inside_init);
4939
4940       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4941         {
4942           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4943
4944           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4945             {
4946               /* For int foo[] = (int [3]){1}; we need to set array size
4947                  now since later on array initializer will be just the
4948                  brace enclosed list of the compound literal.  */
4949               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4950               TREE_TYPE (decl) = type;
4951               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4952               layout_type (type);
4953               layout_decl (cldecl, 0);
4954             }
4955         }
4956     }
4957 }
4958 \f
4959 /* Methods for storing and printing names for error messages.  */
4960
4961 /* Implement a spelling stack that allows components of a name to be pushed
4962    and popped.  Each element on the stack is this structure.  */
4963
4964 struct spelling
4965 {
4966   int kind;
4967   union
4968     {
4969       unsigned HOST_WIDE_INT i;
4970       const char *s;
4971     } u;
4972 };
4973
4974 #define SPELLING_STRING 1
4975 #define SPELLING_MEMBER 2
4976 #define SPELLING_BOUNDS 3
4977
4978 static struct spelling *spelling;       /* Next stack element (unused).  */
4979 static struct spelling *spelling_base;  /* Spelling stack base.  */
4980 static int spelling_size;               /* Size of the spelling stack.  */
4981
4982 /* Macros to save and restore the spelling stack around push_... functions.
4983    Alternative to SAVE_SPELLING_STACK.  */
4984
4985 #define SPELLING_DEPTH() (spelling - spelling_base)
4986 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4987
4988 /* Push an element on the spelling stack with type KIND and assign VALUE
4989    to MEMBER.  */
4990
4991 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4992 {                                                                       \
4993   int depth = SPELLING_DEPTH ();                                        \
4994                                                                         \
4995   if (depth >= spelling_size)                                           \
4996     {                                                                   \
4997       spelling_size += 10;                                              \
4998       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4999                                   spelling_size);                       \
5000       RESTORE_SPELLING_DEPTH (depth);                                   \
5001     }                                                                   \
5002                                                                         \
5003   spelling->kind = (KIND);                                              \
5004   spelling->MEMBER = (VALUE);                                           \
5005   spelling++;                                                           \
5006 }
5007
5008 /* Push STRING on the stack.  Printed literally.  */
5009
5010 static void
5011 push_string (const char *string)
5012 {
5013   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5014 }
5015
5016 /* Push a member name on the stack.  Printed as '.' STRING.  */
5017
5018 static void
5019 push_member_name (tree decl)
5020 {
5021   const char *const string
5022     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
5023   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5024 }
5025
5026 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5027
5028 static void
5029 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5030 {
5031   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5032 }
5033
5034 /* Compute the maximum size in bytes of the printed spelling.  */
5035
5036 static int
5037 spelling_length (void)
5038 {
5039   int size = 0;
5040   struct spelling *p;
5041
5042   for (p = spelling_base; p < spelling; p++)
5043     {
5044       if (p->kind == SPELLING_BOUNDS)
5045         size += 25;
5046       else
5047         size += strlen (p->u.s) + 1;
5048     }
5049
5050   return size;
5051 }
5052
5053 /* Print the spelling to BUFFER and return it.  */
5054
5055 static char *
5056 print_spelling (char *buffer)
5057 {
5058   char *d = buffer;
5059   struct spelling *p;
5060
5061   for (p = spelling_base; p < spelling; p++)
5062     if (p->kind == SPELLING_BOUNDS)
5063       {
5064         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5065         d += strlen (d);
5066       }
5067     else
5068       {
5069         const char *s;
5070         if (p->kind == SPELLING_MEMBER)
5071           *d++ = '.';
5072         for (s = p->u.s; (*d = *s++); d++)
5073           ;
5074       }
5075   *d++ = '\0';
5076   return buffer;
5077 }
5078
5079 /* Issue an error message for a bad initializer component.
5080    MSGID identifies the message.
5081    The component name is taken from the spelling stack.  */
5082
5083 void
5084 error_init (const char *msgid)
5085 {
5086   char *ofwhat;
5087
5088   error ("%s", _(msgid));
5089   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5090   if (*ofwhat)
5091     error ("(near initialization for %qs)", ofwhat);
5092 }
5093
5094 /* Issue a pedantic warning for a bad initializer component.  OPT is
5095    the option OPT_* (from options.h) controlling this warning or 0 if
5096    it is unconditionally given.  MSGID identifies the message.  The
5097    component name is taken from the spelling stack.  */
5098
5099 void
5100 pedwarn_init (location_t location, int opt, const char *msgid)
5101 {
5102   char *ofwhat;
5103
5104   pedwarn (location, opt, "%s", _(msgid));
5105   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5106   if (*ofwhat)
5107     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5108 }
5109
5110 /* Issue a warning for a bad initializer component.
5111
5112    OPT is the OPT_W* value corresponding to the warning option that
5113    controls this warning.  MSGID identifies the message.  The
5114    component name is taken from the spelling stack.  */
5115
5116 static void
5117 warning_init (int opt, const char *msgid)
5118 {
5119   char *ofwhat;
5120
5121   warning (opt, "%s", _(msgid));
5122   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5123   if (*ofwhat)
5124     warning (opt, "(near initialization for %qs)", ofwhat);
5125 }
5126 \f
5127 /* If TYPE is an array type and EXPR is a parenthesized string
5128    constant, warn if pedantic that EXPR is being used to initialize an
5129    object of type TYPE.  */
5130
5131 void
5132 maybe_warn_string_init (tree type, struct c_expr expr)
5133 {
5134   if (pedantic
5135       && TREE_CODE (type) == ARRAY_TYPE
5136       && TREE_CODE (expr.value) == STRING_CST
5137       && expr.original_code != STRING_CST)
5138     pedwarn_init (input_location, OPT_pedantic,
5139                   "array initialized from parenthesized string constant");
5140 }
5141
5142 /* Digest the parser output INIT as an initializer for type TYPE.
5143    Return a C expression of type TYPE to represent the initial value.
5144
5145    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
5146
5147    If INIT is a string constant, STRICT_STRING is true if it is
5148    unparenthesized or we should not warn here for it being parenthesized.
5149    For other types of INIT, STRICT_STRING is not used.
5150
5151    REQUIRE_CONSTANT requests an error if non-constant initializers or
5152    elements are seen.  */
5153
5154 static tree
5155 digest_init (tree type, tree init, bool null_pointer_constant,
5156              bool strict_string, int require_constant)
5157 {
5158   enum tree_code code = TREE_CODE (type);
5159   tree inside_init = init;
5160   tree semantic_type = NULL_TREE;
5161   bool maybe_const = true;
5162
5163   if (type == error_mark_node
5164       || !init
5165       || init == error_mark_node
5166       || TREE_TYPE (init) == error_mark_node)
5167     return error_mark_node;
5168
5169   STRIP_TYPE_NOPS (inside_init);
5170
5171   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
5172     {
5173       semantic_type = TREE_TYPE (inside_init);
5174       inside_init = TREE_OPERAND (inside_init, 0);
5175     }
5176   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
5177   inside_init = decl_constant_value_for_optimization (inside_init);
5178
5179   /* Initialization of an array of chars from a string constant
5180      optionally enclosed in braces.  */
5181
5182   if (code == ARRAY_TYPE && inside_init
5183       && TREE_CODE (inside_init) == STRING_CST)
5184     {
5185       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5186       /* Note that an array could be both an array of character type
5187          and an array of wchar_t if wchar_t is signed char or unsigned
5188          char.  */
5189       bool char_array = (typ1 == char_type_node
5190                          || typ1 == signed_char_type_node
5191                          || typ1 == unsigned_char_type_node);
5192       bool wchar_array = !!comptypes (typ1, wchar_type_node);
5193       bool char16_array = !!comptypes (typ1, char16_type_node);
5194       bool char32_array = !!comptypes (typ1, char32_type_node);
5195
5196       if (char_array || wchar_array || char16_array || char32_array)
5197         {
5198           struct c_expr expr;
5199           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
5200           expr.value = inside_init;
5201           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
5202           expr.original_type = NULL;
5203           maybe_warn_string_init (type, expr);
5204
5205           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5206                          TYPE_MAIN_VARIANT (type)))
5207             return inside_init;
5208
5209           if (char_array)
5210             {
5211               if (typ2 != char_type_node)
5212                 {
5213                   error_init ("char-array initialized from wide string");
5214                   return error_mark_node;
5215                 }
5216             }
5217           else
5218             {
5219               if (typ2 == char_type_node)
5220                 {
5221                   error_init ("wide character array initialized from non-wide "
5222                               "string");
5223                   return error_mark_node;
5224                 }
5225               else if (!comptypes(typ1, typ2))
5226                 {
5227                   error_init ("wide character array initialized from "
5228                               "incompatible wide string");
5229                   return error_mark_node;
5230                 }
5231             }
5232
5233           TREE_TYPE (inside_init) = type;
5234           if (TYPE_DOMAIN (type) != 0
5235               && TYPE_SIZE (type) != 0
5236               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
5237               /* Subtract the size of a single (possibly wide) character
5238                  because it's ok to ignore the terminating null char
5239                  that is counted in the length of the constant.  */
5240               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
5241                                        TREE_STRING_LENGTH (inside_init)
5242                                        - (TYPE_PRECISION (typ1)
5243                                           / BITS_PER_UNIT)))
5244             pedwarn_init (input_location, 0,
5245                           "initializer-string for array of chars is too long");
5246
5247           return inside_init;
5248         }
5249       else if (INTEGRAL_TYPE_P (typ1))
5250         {
5251           error_init ("array of inappropriate type initialized "
5252                       "from string constant");
5253           return error_mark_node;
5254         }
5255     }
5256
5257   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
5258      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
5259      below and handle as a constructor.  */
5260   if (code == VECTOR_TYPE
5261       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
5262       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
5263       && TREE_CONSTANT (inside_init))
5264     {
5265       if (TREE_CODE (inside_init) == VECTOR_CST
5266           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5267                         TYPE_MAIN_VARIANT (type)))
5268         return inside_init;
5269
5270       if (TREE_CODE (inside_init) == CONSTRUCTOR)
5271         {
5272           unsigned HOST_WIDE_INT ix;
5273           tree value;
5274           bool constant_p = true;
5275
5276           /* Iterate through elements and check if all constructor
5277              elements are *_CSTs.  */
5278           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
5279             if (!CONSTANT_CLASS_P (value))
5280               {
5281                 constant_p = false;
5282                 break;
5283               }
5284
5285           if (constant_p)
5286             return build_vector_from_ctor (type,
5287                                            CONSTRUCTOR_ELTS (inside_init));
5288         }
5289     }
5290
5291   if (warn_sequence_point)
5292     verify_sequence_points (inside_init);
5293
5294   /* Any type can be initialized
5295      from an expression of the same type, optionally with braces.  */
5296
5297   if (inside_init && TREE_TYPE (inside_init) != 0
5298       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5299                      TYPE_MAIN_VARIANT (type))
5300           || (code == ARRAY_TYPE
5301               && comptypes (TREE_TYPE (inside_init), type))
5302           || (code == VECTOR_TYPE
5303               && comptypes (TREE_TYPE (inside_init), type))
5304           || (code == POINTER_TYPE
5305               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
5306               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
5307                             TREE_TYPE (type)))))
5308     {
5309       if (code == POINTER_TYPE)
5310         {
5311           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
5312             {
5313               if (TREE_CODE (inside_init) == STRING_CST
5314                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5315                 inside_init = array_to_pointer_conversion (inside_init);
5316               else
5317                 {
5318                   error_init ("invalid use of non-lvalue array");
5319                   return error_mark_node;
5320                 }
5321             }
5322         }
5323
5324       if (code == VECTOR_TYPE)
5325         /* Although the types are compatible, we may require a
5326            conversion.  */
5327         inside_init = convert (type, inside_init);
5328
5329       if (require_constant
5330           && (code == VECTOR_TYPE || !flag_isoc99)
5331           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5332         {
5333           /* As an extension, allow initializing objects with static storage
5334              duration with compound literals (which are then treated just as
5335              the brace enclosed list they contain).  Also allow this for
5336              vectors, as we can only assign them with compound literals.  */
5337           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5338           inside_init = DECL_INITIAL (decl);
5339         }
5340
5341       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
5342           && TREE_CODE (inside_init) != CONSTRUCTOR)
5343         {
5344           error_init ("array initialized from non-constant array expression");
5345           return error_mark_node;
5346         }
5347
5348       /* Compound expressions can only occur here if -pedantic or
5349          -pedantic-errors is specified.  In the later case, we always want
5350          an error.  In the former case, we simply want a warning.  */
5351       if (require_constant && pedantic
5352           && TREE_CODE (inside_init) == COMPOUND_EXPR)
5353         {
5354           inside_init
5355             = valid_compound_expr_initializer (inside_init,
5356                                                TREE_TYPE (inside_init));
5357           if (inside_init == error_mark_node)
5358             error_init ("initializer element is not constant");
5359           else
5360             pedwarn_init (input_location, OPT_pedantic,
5361                           "initializer element is not constant");
5362           if (flag_pedantic_errors)
5363             inside_init = error_mark_node;
5364         }
5365       else if (require_constant
5366                && !initializer_constant_valid_p (inside_init,
5367                                                  TREE_TYPE (inside_init)))
5368         {
5369           error_init ("initializer element is not constant");
5370           inside_init = error_mark_node;
5371         }
5372       else if (require_constant && !maybe_const)
5373         pedwarn_init (input_location, 0,
5374                       "initializer element is not a constant expression");
5375
5376       /* Added to enable additional -Wmissing-format-attribute warnings.  */
5377       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
5378         inside_init = convert_for_assignment (type, inside_init, ic_init,
5379                                               null_pointer_constant,
5380                                               NULL_TREE, NULL_TREE, 0);
5381       return inside_init;
5382     }
5383
5384   /* Handle scalar types, including conversions.  */
5385
5386   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
5387       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
5388       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
5389     {
5390       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
5391           && (TREE_CODE (init) == STRING_CST
5392               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
5393         inside_init = init = array_to_pointer_conversion (init);
5394       if (semantic_type)
5395         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
5396                               inside_init);
5397       inside_init
5398         = convert_for_assignment (type, inside_init, ic_init,
5399                                   null_pointer_constant,
5400                                   NULL_TREE, NULL_TREE, 0);
5401
5402       /* Check to see if we have already given an error message.  */
5403       if (inside_init == error_mark_node)
5404         ;
5405       else if (require_constant && !TREE_CONSTANT (inside_init))
5406         {
5407           error_init ("initializer element is not constant");
5408           inside_init = error_mark_node;
5409         }
5410       else if (require_constant
5411                && !initializer_constant_valid_p (inside_init,
5412                                                  TREE_TYPE (inside_init)))
5413         {
5414           error_init ("initializer element is not computable at load time");
5415           inside_init = error_mark_node;
5416         }
5417       else if (require_constant && !maybe_const)
5418         pedwarn_init (input_location, 0,
5419                       "initializer element is not a constant expression");
5420
5421       return inside_init;
5422     }
5423
5424   /* Come here only for records and arrays.  */
5425
5426   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5427     {
5428       error_init ("variable-sized object may not be initialized");
5429       return error_mark_node;
5430     }
5431
5432   error_init ("invalid initializer");
5433   return error_mark_node;
5434 }
5435 \f
5436 /* Handle initializers that use braces.  */
5437
5438 /* Type of object we are accumulating a constructor for.
5439    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5440 static tree constructor_type;
5441
5442 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
5443    left to fill.  */
5444 static tree constructor_fields;
5445
5446 /* For an ARRAY_TYPE, this is the specified index
5447    at which to store the next element we get.  */
5448 static tree constructor_index;
5449
5450 /* For an ARRAY_TYPE, this is the maximum index.  */
5451 static tree constructor_max_index;
5452
5453 /* For a RECORD_TYPE, this is the first field not yet written out.  */
5454 static tree constructor_unfilled_fields;
5455
5456 /* For an ARRAY_TYPE, this is the index of the first element
5457    not yet written out.  */
5458 static tree constructor_unfilled_index;
5459
5460 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5461    This is so we can generate gaps between fields, when appropriate.  */
5462 static tree constructor_bit_index;
5463
5464 /* If we are saving up the elements rather than allocating them,
5465    this is the list of elements so far (in reverse order,
5466    most recent first).  */
5467 static VEC(constructor_elt,gc) *constructor_elements;
5468
5469 /* 1 if constructor should be incrementally stored into a constructor chain,
5470    0 if all the elements should be kept in AVL tree.  */
5471 static int constructor_incremental;
5472
5473 /* 1 if so far this constructor's elements are all compile-time constants.  */
5474 static int constructor_constant;
5475
5476 /* 1 if so far this constructor's elements are all valid address constants.  */
5477 static int constructor_simple;
5478
5479 /* 1 if this constructor has an element that cannot be part of a
5480    constant expression.  */
5481 static int constructor_nonconst;
5482
5483 /* 1 if this constructor is erroneous so far.  */
5484 static int constructor_erroneous;
5485
5486 /* Structure for managing pending initializer elements, organized as an
5487    AVL tree.  */
5488
5489 struct init_node
5490 {
5491   struct init_node *left, *right;
5492   struct init_node *parent;
5493   int balance;
5494   tree purpose;
5495   tree value;
5496 };
5497
5498 /* Tree of pending elements at this constructor level.
5499    These are elements encountered out of order
5500    which belong at places we haven't reached yet in actually
5501    writing the output.
5502    Will never hold tree nodes across GC runs.  */
5503 static struct init_node *constructor_pending_elts;
5504
5505 /* The SPELLING_DEPTH of this constructor.  */
5506 static int constructor_depth;
5507
5508 /* DECL node for which an initializer is being read.
5509    0 means we are reading a constructor expression
5510    such as (struct foo) {...}.  */
5511 static tree constructor_decl;
5512
5513 /* Nonzero if this is an initializer for a top-level decl.  */
5514 static int constructor_top_level;
5515
5516 /* Nonzero if there were any member designators in this initializer.  */
5517 static int constructor_designated;
5518
5519 /* Nesting depth of designator list.  */
5520 static int designator_depth;
5521
5522 /* Nonzero if there were diagnosed errors in this designator list.  */
5523 static int designator_erroneous;
5524
5525 \f
5526 /* This stack has a level for each implicit or explicit level of
5527    structuring in the initializer, including the outermost one.  It
5528    saves the values of most of the variables above.  */
5529
5530 struct constructor_range_stack;
5531
5532 struct constructor_stack
5533 {
5534   struct constructor_stack *next;
5535   tree type;
5536   tree fields;
5537   tree index;
5538   tree max_index;
5539   tree unfilled_index;
5540   tree unfilled_fields;
5541   tree bit_index;
5542   VEC(constructor_elt,gc) *elements;
5543   struct init_node *pending_elts;
5544   int offset;
5545   int depth;
5546   /* If value nonzero, this value should replace the entire
5547      constructor at this level.  */
5548   struct c_expr replacement_value;
5549   struct constructor_range_stack *range_stack;
5550   char constant;
5551   char simple;
5552   char nonconst;
5553   char implicit;
5554   char erroneous;
5555   char outer;
5556   char incremental;
5557   char designated;
5558 };
5559
5560 static struct constructor_stack *constructor_stack;
5561
5562 /* This stack represents designators from some range designator up to
5563    the last designator in the list.  */
5564
5565 struct constructor_range_stack
5566 {
5567   struct constructor_range_stack *next, *prev;
5568   struct constructor_stack *stack;
5569   tree range_start;
5570   tree index;
5571   tree range_end;
5572   tree fields;
5573 };
5574
5575 static struct constructor_range_stack *constructor_range_stack;
5576
5577 /* This stack records separate initializers that are nested.
5578    Nested initializers can't happen in ANSI C, but GNU C allows them
5579    in cases like { ... (struct foo) { ... } ... }.  */
5580
5581 struct initializer_stack
5582 {
5583   struct initializer_stack *next;
5584   tree decl;
5585   struct constructor_stack *constructor_stack;
5586   struct constructor_range_stack *constructor_range_stack;
5587   VEC(constructor_elt,gc) *elements;
5588   struct spelling *spelling;
5589   struct spelling *spelling_base;
5590   int spelling_size;
5591   char top_level;
5592   char require_constant_value;
5593   char require_constant_elements;
5594 };
5595
5596 static struct initializer_stack *initializer_stack;
5597 \f
5598 /* Prepare to parse and output the initializer for variable DECL.  */
5599
5600 void
5601 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5602 {
5603   const char *locus;
5604   struct initializer_stack *p = XNEW (struct initializer_stack);
5605
5606   p->decl = constructor_decl;
5607   p->require_constant_value = require_constant_value;
5608   p->require_constant_elements = require_constant_elements;
5609   p->constructor_stack = constructor_stack;
5610   p->constructor_range_stack = constructor_range_stack;
5611   p->elements = constructor_elements;
5612   p->spelling = spelling;
5613   p->spelling_base = spelling_base;
5614   p->spelling_size = spelling_size;
5615   p->top_level = constructor_top_level;
5616   p->next = initializer_stack;
5617   initializer_stack = p;
5618
5619   constructor_decl = decl;
5620   constructor_designated = 0;
5621   constructor_top_level = top_level;
5622
5623   if (decl != 0 && decl != error_mark_node)
5624     {
5625       require_constant_value = TREE_STATIC (decl);
5626       require_constant_elements
5627         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5628            /* For a scalar, you can always use any value to initialize,
5629               even within braces.  */
5630            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5631                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5632                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5633                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5634       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5635     }
5636   else
5637     {
5638       require_constant_value = 0;
5639       require_constant_elements = 0;
5640       locus = "(anonymous)";
5641     }
5642
5643   constructor_stack = 0;
5644   constructor_range_stack = 0;
5645
5646   missing_braces_mentioned = 0;
5647
5648   spelling_base = 0;
5649   spelling_size = 0;
5650   RESTORE_SPELLING_DEPTH (0);
5651
5652   if (locus)
5653     push_string (locus);
5654 }
5655
5656 void
5657 finish_init (void)
5658 {
5659   struct initializer_stack *p = initializer_stack;
5660
5661   /* Free the whole constructor stack of this initializer.  */
5662   while (constructor_stack)
5663     {
5664       struct constructor_stack *q = constructor_stack;
5665       constructor_stack = q->next;
5666       free (q);
5667     }
5668
5669   gcc_assert (!constructor_range_stack);
5670
5671   /* Pop back to the data of the outer initializer (if any).  */
5672   free (spelling_base);
5673
5674   constructor_decl = p->decl;
5675   require_constant_value = p->require_constant_value;
5676   require_constant_elements = p->require_constant_elements;
5677   constructor_stack = p->constructor_stack;
5678   constructor_range_stack = p->constructor_range_stack;
5679   constructor_elements = p->elements;
5680   spelling = p->spelling;
5681   spelling_base = p->spelling_base;
5682   spelling_size = p->spelling_size;
5683   constructor_top_level = p->top_level;
5684   initializer_stack = p->next;
5685   free (p);
5686 }
5687 \f
5688 /* Call here when we see the initializer is surrounded by braces.
5689    This is instead of a call to push_init_level;
5690    it is matched by a call to pop_init_level.
5691
5692    TYPE is the type to initialize, for a constructor expression.
5693    For an initializer for a decl, TYPE is zero.  */
5694
5695 void
5696 really_start_incremental_init (tree type)
5697 {
5698   struct constructor_stack *p = XNEW (struct constructor_stack);
5699
5700   if (type == 0)
5701     type = TREE_TYPE (constructor_decl);
5702
5703   if (TREE_CODE (type) == VECTOR_TYPE
5704       && TYPE_VECTOR_OPAQUE (type))
5705     error ("opaque vector types cannot be initialized");
5706
5707   p->type = constructor_type;
5708   p->fields = constructor_fields;
5709   p->index = constructor_index;
5710   p->max_index = constructor_max_index;
5711   p->unfilled_index = constructor_unfilled_index;
5712   p->unfilled_fields = constructor_unfilled_fields;
5713   p->bit_index = constructor_bit_index;
5714   p->elements = constructor_elements;
5715   p->constant = constructor_constant;
5716   p->simple = constructor_simple;
5717   p->nonconst = constructor_nonconst;
5718   p->erroneous = constructor_erroneous;
5719   p->pending_elts = constructor_pending_elts;
5720   p->depth = constructor_depth;
5721   p->replacement_value.value = 0;
5722   p->replacement_value.original_code = ERROR_MARK;
5723   p->replacement_value.original_type = NULL;
5724   p->implicit = 0;
5725   p->range_stack = 0;
5726   p->outer = 0;
5727   p->incremental = constructor_incremental;
5728   p->designated = constructor_designated;
5729   p->next = 0;
5730   constructor_stack = p;
5731
5732   constructor_constant = 1;
5733   constructor_simple = 1;
5734   constructor_nonconst = 0;
5735   constructor_depth = SPELLING_DEPTH ();
5736   constructor_elements = 0;
5737   constructor_pending_elts = 0;
5738   constructor_type = type;
5739   constructor_incremental = 1;
5740   constructor_designated = 0;
5741   designator_depth = 0;
5742   designator_erroneous = 0;
5743
5744   if (TREE_CODE (constructor_type) == RECORD_TYPE
5745       || TREE_CODE (constructor_type) == UNION_TYPE)
5746     {
5747       constructor_fields = TYPE_FIELDS (constructor_type);
5748       /* Skip any nameless bit fields at the beginning.  */
5749       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5750              && DECL_NAME (constructor_fields) == 0)
5751         constructor_fields = TREE_CHAIN (constructor_fields);
5752
5753       constructor_unfilled_fields = constructor_fields;
5754       constructor_bit_index = bitsize_zero_node;
5755     }
5756   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5757     {
5758       if (TYPE_DOMAIN (constructor_type))
5759         {
5760           constructor_max_index
5761             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5762
5763           /* Detect non-empty initializations of zero-length arrays.  */
5764           if (constructor_max_index == NULL_TREE
5765               && TYPE_SIZE (constructor_type))
5766             constructor_max_index = build_int_cst (NULL_TREE, -1);
5767
5768           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5769              to initialize VLAs will cause a proper error; avoid tree
5770              checking errors as well by setting a safe value.  */
5771           if (constructor_max_index
5772               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5773             constructor_max_index = build_int_cst (NULL_TREE, -1);
5774
5775           constructor_index
5776             = convert (bitsizetype,
5777                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5778         }
5779       else
5780         {
5781           constructor_index = bitsize_zero_node;
5782           constructor_max_index = NULL_TREE;
5783         }
5784
5785       constructor_unfilled_index = constructor_index;
5786     }
5787   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5788     {
5789       /* Vectors are like simple fixed-size arrays.  */
5790       constructor_max_index =
5791         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5792       constructor_index = bitsize_zero_node;
5793       constructor_unfilled_index = constructor_index;
5794     }
5795   else
5796     {
5797       /* Handle the case of int x = {5}; */
5798       constructor_fields = constructor_type;
5799       constructor_unfilled_fields = constructor_type;
5800     }
5801 }
5802 \f
5803 /* Push down into a subobject, for initialization.
5804    If this is for an explicit set of braces, IMPLICIT is 0.
5805    If it is because the next element belongs at a lower level,
5806    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5807
5808 void
5809 push_init_level (int implicit)
5810 {
5811   struct constructor_stack *p;
5812   tree value = NULL_TREE;
5813
5814   /* If we've exhausted any levels that didn't have braces,
5815      pop them now.  If implicit == 1, this will have been done in
5816      process_init_element; do not repeat it here because in the case
5817      of excess initializers for an empty aggregate this leads to an
5818      infinite cycle of popping a level and immediately recreating
5819      it.  */
5820   if (implicit != 1)
5821     {
5822       while (constructor_stack->implicit)
5823         {
5824           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5825                || TREE_CODE (constructor_type) == UNION_TYPE)
5826               && constructor_fields == 0)
5827             process_init_element (pop_init_level (1), true);
5828           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5829                    && constructor_max_index
5830                    && tree_int_cst_lt (constructor_max_index,
5831                                        constructor_index))
5832             process_init_element (pop_init_level (1), true);
5833           else
5834             break;
5835         }
5836     }
5837
5838   /* Unless this is an explicit brace, we need to preserve previous
5839      content if any.  */
5840   if (implicit)
5841     {
5842       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5843            || TREE_CODE (constructor_type) == UNION_TYPE)
5844           && constructor_fields)
5845         value = find_init_member (constructor_fields);
5846       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5847         value = find_init_member (constructor_index);
5848     }
5849
5850   p = XNEW (struct constructor_stack);
5851   p->type = constructor_type;
5852   p->fields = constructor_fields;
5853   p->index = constructor_index;
5854   p->max_index = constructor_max_index;
5855   p->unfilled_index = constructor_unfilled_index;
5856   p->unfilled_fields = constructor_unfilled_fields;
5857   p->bit_index = constructor_bit_index;
5858   p->elements = constructor_elements;
5859   p->constant = constructor_constant;
5860   p->simple = constructor_simple;
5861   p->nonconst = constructor_nonconst;
5862   p->erroneous = constructor_erroneous;
5863   p->pending_elts = constructor_pending_elts;
5864   p->depth = constructor_depth;
5865   p->replacement_value.value = 0;
5866   p->replacement_value.original_code = ERROR_MARK;
5867   p->replacement_value.original_type = NULL;
5868   p->implicit = implicit;
5869   p->outer = 0;
5870   p->incremental = constructor_incremental;
5871   p->designated = constructor_designated;
5872   p->next = constructor_stack;
5873   p->range_stack = 0;
5874   constructor_stack = p;
5875
5876   constructor_constant = 1;
5877   constructor_simple = 1;
5878   constructor_nonconst = 0;
5879   constructor_depth = SPELLING_DEPTH ();
5880   constructor_elements = 0;
5881   constructor_incremental = 1;
5882   constructor_designated = 0;
5883   constructor_pending_elts = 0;
5884   if (!implicit)
5885     {
5886       p->range_stack = constructor_range_stack;
5887       constructor_range_stack = 0;
5888       designator_depth = 0;
5889       designator_erroneous = 0;
5890     }
5891
5892   /* Don't die if an entire brace-pair level is superfluous
5893      in the containing level.  */
5894   if (constructor_type == 0)
5895     ;
5896   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5897            || TREE_CODE (constructor_type) == UNION_TYPE)
5898     {
5899       /* Don't die if there are extra init elts at the end.  */
5900       if (constructor_fields == 0)
5901         constructor_type = 0;
5902       else
5903         {
5904           constructor_type = TREE_TYPE (constructor_fields);
5905           push_member_name (constructor_fields);
5906           constructor_depth++;
5907         }
5908     }
5909   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5910     {
5911       constructor_type = TREE_TYPE (constructor_type);
5912       push_array_bounds (tree_low_cst (constructor_index, 1));
5913       constructor_depth++;
5914     }
5915
5916   if (constructor_type == 0)
5917     {
5918       error_init ("extra brace group at end of initializer");
5919       constructor_fields = 0;
5920       constructor_unfilled_fields = 0;
5921       return;
5922     }
5923
5924   if (value && TREE_CODE (value) == CONSTRUCTOR)
5925     {
5926       constructor_constant = TREE_CONSTANT (value);
5927       constructor_simple = TREE_STATIC (value);
5928       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
5929       constructor_elements = CONSTRUCTOR_ELTS (value);
5930       if (!VEC_empty (constructor_elt, constructor_elements)
5931           && (TREE_CODE (constructor_type) == RECORD_TYPE
5932               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5933         set_nonincremental_init ();
5934     }
5935
5936   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5937     {
5938       missing_braces_mentioned = 1;
5939       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5940     }
5941
5942   if (TREE_CODE (constructor_type) == RECORD_TYPE
5943            || TREE_CODE (constructor_type) == UNION_TYPE)
5944     {
5945       constructor_fields = TYPE_FIELDS (constructor_type);
5946       /* Skip any nameless bit fields at the beginning.  */
5947       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5948              && DECL_NAME (constructor_fields) == 0)
5949         constructor_fields = TREE_CHAIN (constructor_fields);
5950
5951       constructor_unfilled_fields = constructor_fields;
5952       constructor_bit_index = bitsize_zero_node;
5953     }
5954   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5955     {
5956       /* Vectors are like simple fixed-size arrays.  */
5957       constructor_max_index =
5958         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5959       constructor_index = convert (bitsizetype, integer_zero_node);
5960       constructor_unfilled_index = constructor_index;
5961     }
5962   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5963     {
5964       if (TYPE_DOMAIN (constructor_type))
5965         {
5966           constructor_max_index
5967             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5968
5969           /* Detect non-empty initializations of zero-length arrays.  */
5970           if (constructor_max_index == NULL_TREE
5971               && TYPE_SIZE (constructor_type))
5972             constructor_max_index = build_int_cst (NULL_TREE, -1);
5973
5974           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5975              to initialize VLAs will cause a proper error; avoid tree
5976              checking errors as well by setting a safe value.  */
5977           if (constructor_max_index
5978               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5979             constructor_max_index = build_int_cst (NULL_TREE, -1);
5980
5981           constructor_index
5982             = convert (bitsizetype,
5983                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5984         }
5985       else
5986         constructor_index = bitsize_zero_node;
5987
5988       constructor_unfilled_index = constructor_index;
5989       if (value && TREE_CODE (value) == STRING_CST)
5990         {
5991           /* We need to split the char/wchar array into individual
5992              characters, so that we don't have to special case it
5993              everywhere.  */
5994           set_nonincremental_init_from_string (value);
5995         }
5996     }
5997   else
5998     {
5999       if (constructor_type != error_mark_node)
6000         warning_init (0, "braces around scalar initializer");
6001       constructor_fields = constructor_type;
6002       constructor_unfilled_fields = constructor_type;
6003     }
6004 }
6005
6006 /* At the end of an implicit or explicit brace level,
6007    finish up that level of constructor.  If a single expression
6008    with redundant braces initialized that level, return the
6009    c_expr structure for that expression.  Otherwise, the original_code
6010    element is set to ERROR_MARK.
6011    If we were outputting the elements as they are read, return 0 as the value
6012    from inner levels (process_init_element ignores that),
6013    but return error_mark_node as the value from the outermost level
6014    (that's what we want to put in DECL_INITIAL).
6015    Otherwise, return a CONSTRUCTOR expression as the value.  */
6016
6017 struct c_expr
6018 pop_init_level (int implicit)
6019 {
6020   struct constructor_stack *p;
6021   struct c_expr ret;
6022   ret.value = 0;
6023   ret.original_code = ERROR_MARK;
6024   ret.original_type = NULL;
6025
6026   if (implicit == 0)
6027     {
6028       /* When we come to an explicit close brace,
6029          pop any inner levels that didn't have explicit braces.  */
6030       while (constructor_stack->implicit)
6031         process_init_element (pop_init_level (1), true);
6032
6033       gcc_assert (!constructor_range_stack);
6034     }
6035
6036   /* Now output all pending elements.  */
6037   constructor_incremental = 1;
6038   output_pending_init_elements (1);
6039
6040   p = constructor_stack;
6041
6042   /* Error for initializing a flexible array member, or a zero-length
6043      array member in an inappropriate context.  */
6044   if (constructor_type && constructor_fields
6045       && TREE_CODE (constructor_type) == ARRAY_TYPE
6046       && TYPE_DOMAIN (constructor_type)
6047       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6048     {
6049       /* Silently discard empty initializations.  The parser will
6050          already have pedwarned for empty brackets.  */
6051       if (integer_zerop (constructor_unfilled_index))
6052         constructor_type = NULL_TREE;
6053       else
6054         {
6055           gcc_assert (!TYPE_SIZE (constructor_type));
6056
6057           if (constructor_depth > 2)
6058             error_init ("initialization of flexible array member in a nested context");
6059           else
6060             pedwarn_init (input_location, OPT_pedantic,
6061                           "initialization of a flexible array member");
6062
6063           /* We have already issued an error message for the existence
6064              of a flexible array member not at the end of the structure.
6065              Discard the initializer so that we do not die later.  */
6066           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
6067             constructor_type = NULL_TREE;
6068         }
6069     }
6070
6071   /* Warn when some struct elements are implicitly initialized to zero.  */
6072   if (warn_missing_field_initializers
6073       && constructor_type
6074       && TREE_CODE (constructor_type) == RECORD_TYPE
6075       && constructor_unfilled_fields)
6076     {
6077         /* Do not warn for flexible array members or zero-length arrays.  */
6078         while (constructor_unfilled_fields
6079                && (!DECL_SIZE (constructor_unfilled_fields)
6080                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6081           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6082
6083         /* Do not warn if this level of the initializer uses member
6084            designators; it is likely to be deliberate.  */
6085         if (constructor_unfilled_fields && !constructor_designated)
6086           {
6087             push_member_name (constructor_unfilled_fields);
6088             warning_init (OPT_Wmissing_field_initializers,
6089                           "missing initializer");
6090             RESTORE_SPELLING_DEPTH (constructor_depth);
6091           }
6092     }
6093
6094   /* Pad out the end of the structure.  */
6095   if (p->replacement_value.value)
6096     /* If this closes a superfluous brace pair,
6097        just pass out the element between them.  */
6098     ret = p->replacement_value;
6099   else if (constructor_type == 0)
6100     ;
6101   else if (TREE_CODE (constructor_type) != RECORD_TYPE
6102            && TREE_CODE (constructor_type) != UNION_TYPE
6103            && TREE_CODE (constructor_type) != ARRAY_TYPE
6104            && TREE_CODE (constructor_type) != VECTOR_TYPE)
6105     {
6106       /* A nonincremental scalar initializer--just return
6107          the element, after verifying there is just one.  */
6108       if (VEC_empty (constructor_elt,constructor_elements))
6109         {
6110           if (!constructor_erroneous)
6111             error_init ("empty scalar initializer");
6112           ret.value = error_mark_node;
6113         }
6114       else if (VEC_length (constructor_elt,constructor_elements) != 1)
6115         {
6116           error_init ("extra elements in scalar initializer");
6117           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6118         }
6119       else
6120         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6121     }
6122   else
6123     {
6124       if (constructor_erroneous)
6125         ret.value = error_mark_node;
6126       else
6127         {
6128           ret.value = build_constructor (constructor_type,
6129                                          constructor_elements);
6130           if (constructor_constant)
6131             TREE_CONSTANT (ret.value) = 1;
6132           if (constructor_constant && constructor_simple)
6133             TREE_STATIC (ret.value) = 1;
6134           if (constructor_nonconst)
6135             CONSTRUCTOR_NON_CONST (ret.value) = 1;
6136         }
6137     }
6138
6139   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
6140     {
6141       if (constructor_nonconst)
6142         ret.original_code = C_MAYBE_CONST_EXPR;
6143       else if (ret.original_code == C_MAYBE_CONST_EXPR)
6144         ret.original_code = ERROR_MARK;
6145     }
6146
6147   constructor_type = p->type;
6148   constructor_fields = p->fields;
6149   constructor_index = p->index;
6150   constructor_max_index = p->max_index;
6151   constructor_unfilled_index = p->unfilled_index;
6152   constructor_unfilled_fields = p->unfilled_fields;
6153   constructor_bit_index = p->bit_index;
6154   constructor_elements = p->elements;
6155   constructor_constant = p->constant;
6156   constructor_simple = p->simple;
6157   constructor_nonconst = p->nonconst;
6158   constructor_erroneous = p->erroneous;
6159   constructor_incremental = p->incremental;
6160   constructor_designated = p->designated;
6161   constructor_pending_elts = p->pending_elts;
6162   constructor_depth = p->depth;
6163   if (!p->implicit)
6164     constructor_range_stack = p->range_stack;
6165   RESTORE_SPELLING_DEPTH (constructor_depth);
6166
6167   constructor_stack = p->next;
6168   free (p);
6169
6170   if (ret.value == 0 && constructor_stack == 0)
6171     ret.value = error_mark_node;
6172   return ret;
6173 }
6174
6175 /* Common handling for both array range and field name designators.
6176    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
6177
6178 static int
6179 set_designator (int array)
6180 {
6181   tree subtype;
6182   enum tree_code subcode;
6183
6184   /* Don't die if an entire brace-pair level is superfluous
6185      in the containing level.  */
6186   if (constructor_type == 0)
6187     return 1;
6188
6189   /* If there were errors in this designator list already, bail out
6190      silently.  */
6191   if (designator_erroneous)
6192     return 1;
6193
6194   if (!designator_depth)
6195     {
6196       gcc_assert (!constructor_range_stack);
6197
6198       /* Designator list starts at the level of closest explicit
6199          braces.  */
6200       while (constructor_stack->implicit)
6201         process_init_element (pop_init_level (1), true);
6202       constructor_designated = 1;
6203       return 0;
6204     }
6205
6206   switch (TREE_CODE (constructor_type))
6207     {
6208     case  RECORD_TYPE:
6209     case  UNION_TYPE:
6210       subtype = TREE_TYPE (constructor_fields);
6211       if (subtype != error_mark_node)
6212         subtype = TYPE_MAIN_VARIANT (subtype);
6213       break;
6214     case ARRAY_TYPE:
6215       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6216       break;
6217     default:
6218       gcc_unreachable ();
6219     }
6220
6221   subcode = TREE_CODE (subtype);
6222   if (array && subcode != ARRAY_TYPE)
6223     {
6224       error_init ("array index in non-array initializer");
6225       return 1;
6226     }
6227   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
6228     {
6229       error_init ("field name not in record or union initializer");
6230       return 1;
6231     }
6232
6233   constructor_designated = 1;
6234   push_init_level (2);
6235   return 0;
6236 }
6237
6238 /* If there are range designators in designator list, push a new designator
6239    to constructor_range_stack.  RANGE_END is end of such stack range or
6240    NULL_TREE if there is no range designator at this level.  */
6241
6242 static void
6243 push_range_stack (tree range_end)
6244 {
6245   struct constructor_range_stack *p;
6246
6247   p = GGC_NEW (struct constructor_range_stack);
6248   p->prev = constructor_range_stack;
6249   p->next = 0;
6250   p->fields = constructor_fields;
6251   p->range_start = constructor_index;
6252   p->index = constructor_index;
6253   p->stack = constructor_stack;
6254   p->range_end = range_end;
6255   if (constructor_range_stack)
6256     constructor_range_stack->next = p;
6257   constructor_range_stack = p;
6258 }
6259
6260 /* Within an array initializer, specify the next index to be initialized.
6261    FIRST is that index.  If LAST is nonzero, then initialize a range
6262    of indices, running from FIRST through LAST.  */
6263
6264 void
6265 set_init_index (tree first, tree last)
6266 {
6267   if (set_designator (1))
6268     return;
6269
6270   designator_erroneous = 1;
6271
6272   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
6273       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
6274     {
6275       error_init ("array index in initializer not of integer type");
6276       return;
6277     }
6278
6279   if (TREE_CODE (first) != INTEGER_CST)
6280     error_init ("nonconstant array index in initializer");
6281   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
6282     error_init ("nonconstant array index in initializer");
6283   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
6284     error_init ("array index in non-array initializer");
6285   else if (tree_int_cst_sgn (first) == -1)
6286     error_init ("array index in initializer exceeds array bounds");
6287   else if (constructor_max_index
6288            && tree_int_cst_lt (constructor_max_index, first))
6289     error_init ("array index in initializer exceeds array bounds");
6290   else
6291     {
6292       constant_expression_warning (first);
6293       if (last)
6294         constant_expression_warning (last);
6295       constructor_index = convert (bitsizetype, first);
6296
6297       if (last)
6298         {
6299           if (tree_int_cst_equal (first, last))
6300             last = 0;
6301           else if (tree_int_cst_lt (last, first))
6302             {
6303               error_init ("empty index range in initializer");
6304               last = 0;
6305             }
6306           else
6307             {
6308               last = convert (bitsizetype, last);
6309               if (constructor_max_index != 0
6310                   && tree_int_cst_lt (constructor_max_index, last))
6311                 {
6312                   error_init ("array index range in initializer exceeds array bounds");
6313                   last = 0;
6314                 }
6315             }
6316         }
6317
6318       designator_depth++;
6319       designator_erroneous = 0;
6320       if (constructor_range_stack || last)
6321         push_range_stack (last);
6322     }
6323 }
6324
6325 /* Within a struct initializer, specify the next field to be initialized.  */
6326
6327 void
6328 set_init_label (tree fieldname)
6329 {
6330   tree tail;
6331
6332   if (set_designator (0))
6333     return;
6334
6335   designator_erroneous = 1;
6336
6337   if (TREE_CODE (constructor_type) != RECORD_TYPE
6338       && TREE_CODE (constructor_type) != UNION_TYPE)
6339     {
6340       error_init ("field name not in record or union initializer");
6341       return;
6342     }
6343
6344   for (tail = TYPE_FIELDS (constructor_type); tail;
6345        tail = TREE_CHAIN (tail))
6346     {
6347       if (DECL_NAME (tail) == fieldname)
6348         break;
6349     }
6350
6351   if (tail == 0)
6352     error ("unknown field %qE specified in initializer", fieldname);
6353   else
6354     {
6355       constructor_fields = tail;
6356       designator_depth++;
6357       designator_erroneous = 0;
6358       if (constructor_range_stack)
6359         push_range_stack (NULL_TREE);
6360     }
6361 }
6362 \f
6363 /* Add a new initializer to the tree of pending initializers.  PURPOSE
6364    identifies the initializer, either array index or field in a structure.
6365    VALUE is the value of that index or field.
6366
6367    IMPLICIT is true if value comes from pop_init_level (1),
6368    the new initializer has been merged with the existing one
6369    and thus no warnings should be emitted about overriding an
6370    existing initializer.  */
6371
6372 static void
6373 add_pending_init (tree purpose, tree value, bool implicit)
6374 {
6375   struct init_node *p, **q, *r;
6376
6377   q = &constructor_pending_elts;
6378   p = 0;
6379
6380   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6381     {
6382       while (*q != 0)
6383         {
6384           p = *q;
6385           if (tree_int_cst_lt (purpose, p->purpose))
6386             q = &p->left;
6387           else if (tree_int_cst_lt (p->purpose, purpose))
6388             q = &p->right;
6389           else
6390             {
6391               if (!implicit)
6392                 {
6393                   if (TREE_SIDE_EFFECTS (p->value))
6394                     warning_init (0, "initialized field with side-effects overwritten");
6395                   else if (warn_override_init)
6396                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6397                 }
6398               p->value = value;
6399               return;
6400             }
6401         }
6402     }
6403   else
6404     {
6405       tree bitpos;
6406
6407       bitpos = bit_position (purpose);
6408       while (*q != NULL)
6409         {
6410           p = *q;
6411           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6412             q = &p->left;
6413           else if (p->purpose != purpose)
6414             q = &p->right;
6415           else
6416             {
6417               if (!implicit)
6418                 {
6419                   if (TREE_SIDE_EFFECTS (p->value))
6420                     warning_init (0, "initialized field with side-effects overwritten");
6421                   else if (warn_override_init)
6422                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6423                 }
6424               p->value = value;
6425               return;
6426             }
6427         }
6428     }
6429
6430   r = GGC_NEW (struct init_node);
6431   r->purpose = purpose;
6432   r->value = value;
6433
6434   *q = r;
6435   r->parent = p;
6436   r->left = 0;
6437   r->right = 0;
6438   r->balance = 0;
6439
6440   while (p)
6441     {
6442       struct init_node *s;
6443
6444       if (r == p->left)
6445         {
6446           if (p->balance == 0)
6447             p->balance = -1;
6448           else if (p->balance < 0)
6449             {
6450               if (r->balance < 0)
6451                 {
6452                   /* L rotation.  */
6453                   p->left = r->right;
6454                   if (p->left)
6455                     p->left->parent = p;
6456                   r->right = p;
6457
6458                   p->balance = 0;
6459                   r->balance = 0;
6460
6461                   s = p->parent;
6462                   p->parent = r;
6463                   r->parent = s;
6464                   if (s)
6465                     {
6466                       if (s->left == p)
6467                         s->left = r;
6468                       else
6469                         s->right = r;
6470                     }
6471                   else
6472                     constructor_pending_elts = r;
6473                 }
6474               else
6475                 {
6476                   /* LR rotation.  */
6477                   struct init_node *t = r->right;
6478
6479                   r->right = t->left;
6480                   if (r->right)
6481                     r->right->parent = r;
6482                   t->left = r;
6483
6484                   p->left = t->right;
6485                   if (p->left)
6486                     p->left->parent = p;
6487                   t->right = p;
6488
6489                   p->balance = t->balance < 0;
6490                   r->balance = -(t->balance > 0);
6491                   t->balance = 0;
6492
6493                   s = p->parent;
6494                   p->parent = t;
6495                   r->parent = t;
6496                   t->parent = s;
6497                   if (s)
6498                     {
6499                       if (s->left == p)
6500                         s->left = t;
6501                       else
6502                         s->right = t;
6503                     }
6504                   else
6505                     constructor_pending_elts = t;
6506                 }
6507               break;
6508             }
6509           else
6510             {
6511               /* p->balance == +1; growth of left side balances the node.  */
6512               p->balance = 0;
6513               break;
6514             }
6515         }
6516       else /* r == p->right */
6517         {
6518           if (p->balance == 0)
6519             /* Growth propagation from right side.  */
6520             p->balance++;
6521           else if (p->balance > 0)
6522             {
6523               if (r->balance > 0)
6524                 {
6525                   /* R rotation.  */
6526                   p->right = r->left;
6527                   if (p->right)
6528                     p->right->parent = p;
6529                   r->left = p;
6530
6531                   p->balance = 0;
6532                   r->balance = 0;
6533
6534                   s = p->parent;
6535                   p->parent = r;
6536                   r->parent = s;
6537                   if (s)
6538                     {
6539                       if (s->left == p)
6540                         s->left = r;
6541                       else
6542                         s->right = r;
6543                     }
6544                   else
6545                     constructor_pending_elts = r;
6546                 }
6547               else /* r->balance == -1 */
6548                 {
6549                   /* RL rotation */
6550                   struct init_node *t = r->left;
6551
6552                   r->left = t->right;
6553                   if (r->left)
6554                     r->left->parent = r;
6555                   t->right = r;
6556
6557                   p->right = t->left;
6558                   if (p->right)
6559                     p->right->parent = p;
6560                   t->left = p;
6561
6562                   r->balance = (t->balance < 0);
6563                   p->balance = -(t->balance > 0);
6564                   t->balance = 0;
6565
6566                   s = p->parent;
6567                   p->parent = t;
6568                   r->parent = t;
6569                   t->parent = s;
6570                   if (s)
6571                     {
6572                       if (s->left == p)
6573                         s->left = t;
6574                       else
6575                         s->right = t;
6576                     }
6577                   else
6578                     constructor_pending_elts = t;
6579                 }
6580               break;
6581             }
6582           else
6583             {
6584               /* p->balance == -1; growth of right side balances the node.  */
6585               p->balance = 0;
6586               break;
6587             }
6588         }
6589
6590       r = p;
6591       p = p->parent;
6592     }
6593 }
6594
6595 /* Build AVL tree from a sorted chain.  */
6596
6597 static void
6598 set_nonincremental_init (void)
6599 {
6600   unsigned HOST_WIDE_INT ix;
6601   tree index, value;
6602
6603   if (TREE_CODE (constructor_type) != RECORD_TYPE
6604       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6605     return;
6606
6607   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6608     add_pending_init (index, value, false);
6609   constructor_elements = 0;
6610   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6611     {
6612       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6613       /* Skip any nameless bit fields at the beginning.  */
6614       while (constructor_unfilled_fields != 0
6615              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6616              && DECL_NAME (constructor_unfilled_fields) == 0)
6617         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6618
6619     }
6620   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6621     {
6622       if (TYPE_DOMAIN (constructor_type))
6623         constructor_unfilled_index
6624             = convert (bitsizetype,
6625                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6626       else
6627         constructor_unfilled_index = bitsize_zero_node;
6628     }
6629   constructor_incremental = 0;
6630 }
6631
6632 /* Build AVL tree from a string constant.  */
6633
6634 static void
6635 set_nonincremental_init_from_string (tree str)
6636 {
6637   tree value, purpose, type;
6638   HOST_WIDE_INT val[2];
6639   const char *p, *end;
6640   int byte, wchar_bytes, charwidth, bitpos;
6641
6642   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6643
6644   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
6645   charwidth = TYPE_PRECISION (char_type_node);
6646   type = TREE_TYPE (constructor_type);
6647   p = TREE_STRING_POINTER (str);
6648   end = p + TREE_STRING_LENGTH (str);
6649
6650   for (purpose = bitsize_zero_node;
6651        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6652        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6653     {
6654       if (wchar_bytes == 1)
6655         {
6656           val[1] = (unsigned char) *p++;
6657           val[0] = 0;
6658         }
6659       else
6660         {
6661           val[0] = 0;
6662           val[1] = 0;
6663           for (byte = 0; byte < wchar_bytes; byte++)
6664             {
6665               if (BYTES_BIG_ENDIAN)
6666                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6667               else
6668                 bitpos = byte * charwidth;
6669               val[bitpos < HOST_BITS_PER_WIDE_INT]
6670                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6671                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6672             }
6673         }
6674
6675       if (!TYPE_UNSIGNED (type))
6676         {
6677           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6678           if (bitpos < HOST_BITS_PER_WIDE_INT)
6679             {
6680               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6681                 {
6682                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6683                   val[0] = -1;
6684                 }
6685             }
6686           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6687             {
6688               if (val[1] < 0)
6689                 val[0] = -1;
6690             }
6691           else if (val[0] & (((HOST_WIDE_INT) 1)
6692                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6693             val[0] |= ((HOST_WIDE_INT) -1)
6694                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6695         }
6696
6697       value = build_int_cst_wide (type, val[1], val[0]);
6698       add_pending_init (purpose, value, false);
6699     }
6700
6701   constructor_incremental = 0;
6702 }
6703
6704 /* Return value of FIELD in pending initializer or zero if the field was
6705    not initialized yet.  */
6706
6707 static tree
6708 find_init_member (tree field)
6709 {
6710   struct init_node *p;
6711
6712   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6713     {
6714       if (constructor_incremental
6715           && tree_int_cst_lt (field, constructor_unfilled_index))
6716         set_nonincremental_init ();
6717
6718       p = constructor_pending_elts;
6719       while (p)
6720         {
6721           if (tree_int_cst_lt (field, p->purpose))
6722             p = p->left;
6723           else if (tree_int_cst_lt (p->purpose, field))
6724             p = p->right;
6725           else
6726             return p->value;
6727         }
6728     }
6729   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6730     {
6731       tree bitpos = bit_position (field);
6732
6733       if (constructor_incremental
6734           && (!constructor_unfilled_fields
6735               || tree_int_cst_lt (bitpos,
6736                                   bit_position (constructor_unfilled_fields))))
6737         set_nonincremental_init ();
6738
6739       p = constructor_pending_elts;
6740       while (p)
6741         {
6742           if (field == p->purpose)
6743             return p->value;
6744           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6745             p = p->left;
6746           else
6747             p = p->right;
6748         }
6749     }
6750   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6751     {
6752       if (!VEC_empty (constructor_elt, constructor_elements)
6753           && (VEC_last (constructor_elt, constructor_elements)->index
6754               == field))
6755         return VEC_last (constructor_elt, constructor_elements)->value;
6756     }
6757   return 0;
6758 }
6759
6760 /* "Output" the next constructor element.
6761    At top level, really output it to assembler code now.
6762    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6763    TYPE is the data type that the containing data type wants here.
6764    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6765    If VALUE is a string constant, STRICT_STRING is true if it is
6766    unparenthesized or we should not warn here for it being parenthesized.
6767    For other types of VALUE, STRICT_STRING is not used.
6768
6769    PENDING if non-nil means output pending elements that belong
6770    right after this element.  (PENDING is normally 1;
6771    it is 0 while outputting pending elements, to avoid recursion.)
6772
6773    IMPLICIT is true if value comes from pop_init_level (1),
6774    the new initializer has been merged with the existing one
6775    and thus no warnings should be emitted about overriding an
6776    existing initializer.  */
6777
6778 static void
6779 output_init_element (tree value, bool strict_string, tree type, tree field,
6780                      int pending, bool implicit)
6781 {
6782   tree semantic_type = NULL_TREE;
6783   constructor_elt *celt;
6784   bool maybe_const = true;
6785   bool npc;
6786
6787   if (type == error_mark_node || value == error_mark_node)
6788     {
6789       constructor_erroneous = 1;
6790       return;
6791     }
6792   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6793       && (TREE_CODE (value) == STRING_CST
6794           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6795       && !(TREE_CODE (value) == STRING_CST
6796            && TREE_CODE (type) == ARRAY_TYPE
6797            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6798       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6799                      TYPE_MAIN_VARIANT (type)))
6800     value = array_to_pointer_conversion (value);
6801
6802   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6803       && require_constant_value && !flag_isoc99 && pending)
6804     {
6805       /* As an extension, allow initializing objects with static storage
6806          duration with compound literals (which are then treated just as
6807          the brace enclosed list they contain).  */
6808       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6809       value = DECL_INITIAL (decl);
6810     }
6811
6812   npc = null_pointer_constant_p (value);
6813   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
6814     {
6815       semantic_type = TREE_TYPE (value);
6816       value = TREE_OPERAND (value, 0);
6817     }
6818   value = c_fully_fold (value, require_constant_value, &maybe_const);
6819
6820   if (value == error_mark_node)
6821     constructor_erroneous = 1;
6822   else if (!TREE_CONSTANT (value))
6823     constructor_constant = 0;
6824   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6825            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6826                 || TREE_CODE (constructor_type) == UNION_TYPE)
6827                && DECL_C_BIT_FIELD (field)
6828                && TREE_CODE (value) != INTEGER_CST))
6829     constructor_simple = 0;
6830   if (!maybe_const)
6831     constructor_nonconst = 1;
6832
6833   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6834     {
6835       if (require_constant_value)
6836         {
6837           error_init ("initializer element is not constant");
6838           value = error_mark_node;
6839         }
6840       else if (require_constant_elements)
6841         pedwarn (input_location, 0,
6842                  "initializer element is not computable at load time");
6843     }
6844   else if (!maybe_const
6845            && (require_constant_value || require_constant_elements))
6846     pedwarn_init (input_location, 0,
6847                   "initializer element is not a constant expression");
6848
6849   /* If this field is empty (and not at the end of structure),
6850      don't do anything other than checking the initializer.  */
6851   if (field
6852       && (TREE_TYPE (field) == error_mark_node
6853           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6854               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6855               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6856                   || TREE_CHAIN (field)))))
6857     return;
6858
6859   if (semantic_type)
6860     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
6861   value = digest_init (type, value, npc, strict_string,
6862                        require_constant_value);
6863   if (value == error_mark_node)
6864     {
6865       constructor_erroneous = 1;
6866       return;
6867     }
6868   if (require_constant_value || require_constant_elements)
6869     constant_expression_warning (value);
6870
6871   /* If this element doesn't come next in sequence,
6872      put it on constructor_pending_elts.  */
6873   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6874       && (!constructor_incremental
6875           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6876     {
6877       if (constructor_incremental
6878           && tree_int_cst_lt (field, constructor_unfilled_index))
6879         set_nonincremental_init ();
6880
6881       add_pending_init (field, value, implicit);
6882       return;
6883     }
6884   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6885            && (!constructor_incremental
6886                || field != constructor_unfilled_fields))
6887     {
6888       /* We do this for records but not for unions.  In a union,
6889          no matter which field is specified, it can be initialized
6890          right away since it starts at the beginning of the union.  */
6891       if (constructor_incremental)
6892         {
6893           if (!constructor_unfilled_fields)
6894             set_nonincremental_init ();
6895           else
6896             {
6897               tree bitpos, unfillpos;
6898
6899               bitpos = bit_position (field);
6900               unfillpos = bit_position (constructor_unfilled_fields);
6901
6902               if (tree_int_cst_lt (bitpos, unfillpos))
6903                 set_nonincremental_init ();
6904             }
6905         }
6906
6907       add_pending_init (field, value, implicit);
6908       return;
6909     }
6910   else if (TREE_CODE (constructor_type) == UNION_TYPE
6911            && !VEC_empty (constructor_elt, constructor_elements))
6912     {
6913       if (!implicit)
6914         {
6915           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6916                                            constructor_elements)->value))
6917             warning_init (0,
6918                           "initialized field with side-effects overwritten");
6919           else if (warn_override_init)
6920             warning_init (OPT_Woverride_init, "initialized field overwritten");
6921         }
6922
6923       /* We can have just one union field set.  */
6924       constructor_elements = 0;
6925     }
6926
6927   /* Otherwise, output this element either to
6928      constructor_elements or to the assembler file.  */
6929
6930   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6931   celt->index = field;
6932   celt->value = value;
6933
6934   /* Advance the variable that indicates sequential elements output.  */
6935   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6936     constructor_unfilled_index
6937       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6938                     bitsize_one_node);
6939   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6940     {
6941       constructor_unfilled_fields
6942         = TREE_CHAIN (constructor_unfilled_fields);
6943
6944       /* Skip any nameless bit fields.  */
6945       while (constructor_unfilled_fields != 0
6946              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6947              && DECL_NAME (constructor_unfilled_fields) == 0)
6948         constructor_unfilled_fields =
6949           TREE_CHAIN (constructor_unfilled_fields);
6950     }
6951   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6952     constructor_unfilled_fields = 0;
6953
6954   /* Now output any pending elements which have become next.  */
6955   if (pending)
6956     output_pending_init_elements (0);
6957 }
6958
6959 /* Output any pending elements which have become next.
6960    As we output elements, constructor_unfilled_{fields,index}
6961    advances, which may cause other elements to become next;
6962    if so, they too are output.
6963
6964    If ALL is 0, we return when there are
6965    no more pending elements to output now.
6966
6967    If ALL is 1, we output space as necessary so that
6968    we can output all the pending elements.  */
6969
6970 static void
6971 output_pending_init_elements (int all)
6972 {
6973   struct init_node *elt = constructor_pending_elts;
6974   tree next;
6975
6976  retry:
6977
6978   /* Look through the whole pending tree.
6979      If we find an element that should be output now,
6980      output it.  Otherwise, set NEXT to the element
6981      that comes first among those still pending.  */
6982
6983   next = 0;
6984   while (elt)
6985     {
6986       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6987         {
6988           if (tree_int_cst_equal (elt->purpose,
6989                                   constructor_unfilled_index))
6990             output_init_element (elt->value, true,
6991                                  TREE_TYPE (constructor_type),
6992                                  constructor_unfilled_index, 0, false);
6993           else if (tree_int_cst_lt (constructor_unfilled_index,
6994                                     elt->purpose))
6995             {
6996               /* Advance to the next smaller node.  */
6997               if (elt->left)
6998                 elt = elt->left;
6999               else
7000                 {
7001                   /* We have reached the smallest node bigger than the
7002                      current unfilled index.  Fill the space first.  */
7003                   next = elt->purpose;
7004                   break;
7005                 }
7006             }
7007           else
7008             {
7009               /* Advance to the next bigger node.  */
7010               if (elt->right)
7011                 elt = elt->right;
7012               else
7013                 {
7014                   /* We have reached the biggest node in a subtree.  Find
7015                      the parent of it, which is the next bigger node.  */
7016                   while (elt->parent && elt->parent->right == elt)
7017                     elt = elt->parent;
7018                   elt = elt->parent;
7019                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7020                                               elt->purpose))
7021                     {
7022                       next = elt->purpose;
7023                       break;
7024                     }
7025                 }
7026             }
7027         }
7028       else if (TREE_CODE (constructor_type) == RECORD_TYPE
7029                || TREE_CODE (constructor_type) == UNION_TYPE)
7030         {
7031           tree ctor_unfilled_bitpos, elt_bitpos;
7032
7033           /* If the current record is complete we are done.  */
7034           if (constructor_unfilled_fields == 0)
7035             break;
7036
7037           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
7038           elt_bitpos = bit_position (elt->purpose);
7039           /* We can't compare fields here because there might be empty
7040              fields in between.  */
7041           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
7042             {
7043               constructor_unfilled_fields = elt->purpose;
7044               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
7045                                    elt->purpose, 0, false);
7046             }
7047           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
7048             {
7049               /* Advance to the next smaller node.  */
7050               if (elt->left)
7051                 elt = elt->left;
7052               else
7053                 {
7054                   /* We have reached the smallest node bigger than the
7055                      current unfilled field.  Fill the space first.  */
7056                   next = elt->purpose;
7057                   break;
7058                 }
7059             }
7060           else
7061             {
7062               /* Advance to the next bigger node.  */
7063               if (elt->right)
7064                 elt = elt->right;
7065               else
7066                 {
7067                   /* We have reached the biggest node in a subtree.  Find
7068                      the parent of it, which is the next bigger node.  */
7069                   while (elt->parent && elt->parent->right == elt)
7070                     elt = elt->parent;
7071                   elt = elt->parent;
7072                   if (elt
7073                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
7074                                            bit_position (elt->purpose))))
7075                     {
7076                       next = elt->purpose;
7077                       break;
7078                     }
7079                 }
7080             }
7081         }
7082     }
7083
7084   /* Ordinarily return, but not if we want to output all
7085      and there are elements left.  */
7086   if (!(all && next != 0))
7087     return;
7088
7089   /* If it's not incremental, just skip over the gap, so that after
7090      jumping to retry we will output the next successive element.  */
7091   if (TREE_CODE (constructor_type) == RECORD_TYPE
7092       || TREE_CODE (constructor_type) == UNION_TYPE)
7093     constructor_unfilled_fields = next;
7094   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7095     constructor_unfilled_index = next;
7096
7097   /* ELT now points to the node in the pending tree with the next
7098      initializer to output.  */
7099   goto retry;
7100 }
7101 \f
7102 /* Add one non-braced element to the current constructor level.
7103    This adjusts the current position within the constructor's type.
7104    This may also start or terminate implicit levels
7105    to handle a partly-braced initializer.
7106
7107    Once this has found the correct level for the new element,
7108    it calls output_init_element.
7109
7110    IMPLICIT is true if value comes from pop_init_level (1),
7111    the new initializer has been merged with the existing one
7112    and thus no warnings should be emitted about overriding an
7113    existing initializer.  */
7114
7115 void
7116 process_init_element (struct c_expr value, bool implicit)
7117 {
7118   tree orig_value = value.value;
7119   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
7120   bool strict_string = value.original_code == STRING_CST;
7121
7122   designator_depth = 0;
7123   designator_erroneous = 0;
7124
7125   /* Handle superfluous braces around string cst as in
7126      char x[] = {"foo"}; */
7127   if (string_flag
7128       && constructor_type
7129       && TREE_CODE (constructor_type) == ARRAY_TYPE
7130       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
7131       && integer_zerop (constructor_unfilled_index))
7132     {
7133       if (constructor_stack->replacement_value.value)
7134         error_init ("excess elements in char array initializer");
7135       constructor_stack->replacement_value = value;
7136       return;
7137     }
7138
7139   if (constructor_stack->replacement_value.value != 0)
7140     {
7141       error_init ("excess elements in struct initializer");
7142       return;
7143     }
7144
7145   /* Ignore elements of a brace group if it is entirely superfluous
7146      and has already been diagnosed.  */
7147   if (constructor_type == 0)
7148     return;
7149
7150   /* If we've exhausted any levels that didn't have braces,
7151      pop them now.  */
7152   while (constructor_stack->implicit)
7153     {
7154       if ((TREE_CODE (constructor_type) == RECORD_TYPE
7155            || TREE_CODE (constructor_type) == UNION_TYPE)
7156           && constructor_fields == 0)
7157         process_init_element (pop_init_level (1), true);
7158       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
7159                && (constructor_max_index == 0
7160                    || tree_int_cst_lt (constructor_max_index,
7161                                        constructor_index)))
7162         process_init_element (pop_init_level (1), true);
7163       else
7164         break;
7165     }
7166
7167   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
7168   if (constructor_range_stack)
7169     {
7170       /* If value is a compound literal and we'll be just using its
7171          content, don't put it into a SAVE_EXPR.  */
7172       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
7173           || !require_constant_value
7174           || flag_isoc99)
7175         {
7176           tree semantic_type = NULL_TREE;
7177           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
7178             {
7179               semantic_type = TREE_TYPE (value.value);
7180               value.value = TREE_OPERAND (value.value, 0);
7181             }
7182           value.value = c_save_expr (value.value);
7183           if (semantic_type)
7184             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
7185                                   value.value);
7186         }
7187     }
7188
7189   while (1)
7190     {
7191       if (TREE_CODE (constructor_type) == RECORD_TYPE)
7192         {
7193           tree fieldtype;
7194           enum tree_code fieldcode;
7195
7196           if (constructor_fields == 0)
7197             {
7198               pedwarn_init (input_location, 0,
7199                             "excess elements in struct initializer");
7200               break;
7201             }
7202
7203           fieldtype = TREE_TYPE (constructor_fields);
7204           if (fieldtype != error_mark_node)
7205             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7206           fieldcode = TREE_CODE (fieldtype);
7207
7208           /* Error for non-static initialization of a flexible array member.  */
7209           if (fieldcode == ARRAY_TYPE
7210               && !require_constant_value
7211               && TYPE_SIZE (fieldtype) == NULL_TREE
7212               && TREE_CHAIN (constructor_fields) == NULL_TREE)
7213             {
7214               error_init ("non-static initialization of a flexible array member");
7215               break;
7216             }
7217
7218           /* Accept a string constant to initialize a subarray.  */
7219           if (value.value != 0
7220               && fieldcode == ARRAY_TYPE
7221               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7222               && string_flag)
7223             value.value = orig_value;
7224           /* Otherwise, if we have come to a subaggregate,
7225              and we don't have an element of its type, push into it.  */
7226           else if (value.value != 0
7227                    && value.value != error_mark_node
7228                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7229                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7230                        || fieldcode == UNION_TYPE))
7231             {
7232               push_init_level (1);
7233               continue;
7234             }
7235
7236           if (value.value)
7237             {
7238               push_member_name (constructor_fields);
7239               output_init_element (value.value, strict_string,
7240                                    fieldtype, constructor_fields, 1, implicit);
7241               RESTORE_SPELLING_DEPTH (constructor_depth);
7242             }
7243           else
7244             /* Do the bookkeeping for an element that was
7245                directly output as a constructor.  */
7246             {
7247               /* For a record, keep track of end position of last field.  */
7248               if (DECL_SIZE (constructor_fields))
7249                 constructor_bit_index
7250                   = size_binop (PLUS_EXPR,
7251                                 bit_position (constructor_fields),
7252                                 DECL_SIZE (constructor_fields));
7253
7254               /* If the current field was the first one not yet written out,
7255                  it isn't now, so update.  */
7256               if (constructor_unfilled_fields == constructor_fields)
7257                 {
7258                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7259                   /* Skip any nameless bit fields.  */
7260                   while (constructor_unfilled_fields != 0
7261                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7262                          && DECL_NAME (constructor_unfilled_fields) == 0)
7263                     constructor_unfilled_fields =
7264                       TREE_CHAIN (constructor_unfilled_fields);
7265                 }
7266             }
7267
7268           constructor_fields = TREE_CHAIN (constructor_fields);
7269           /* Skip any nameless bit fields at the beginning.  */
7270           while (constructor_fields != 0
7271                  && DECL_C_BIT_FIELD (constructor_fields)
7272                  && DECL_NAME (constructor_fields) == 0)
7273             constructor_fields = TREE_CHAIN (constructor_fields);
7274         }
7275       else if (TREE_CODE (constructor_type) == UNION_TYPE)
7276         {
7277           tree fieldtype;
7278           enum tree_code fieldcode;
7279
7280           if (constructor_fields == 0)
7281             {
7282               pedwarn_init (input_location, 0,
7283                             "excess elements in union initializer");
7284               break;
7285             }
7286
7287           fieldtype = TREE_TYPE (constructor_fields);
7288           if (fieldtype != error_mark_node)
7289             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7290           fieldcode = TREE_CODE (fieldtype);
7291
7292           /* Warn that traditional C rejects initialization of unions.
7293              We skip the warning if the value is zero.  This is done
7294              under the assumption that the zero initializer in user
7295              code appears conditioned on e.g. __STDC__ to avoid
7296              "missing initializer" warnings and relies on default
7297              initialization to zero in the traditional C case.
7298              We also skip the warning if the initializer is designated,
7299              again on the assumption that this must be conditional on
7300              __STDC__ anyway (and we've already complained about the
7301              member-designator already).  */
7302           if (!in_system_header && !constructor_designated
7303               && !(value.value && (integer_zerop (value.value)
7304                                    || real_zerop (value.value))))
7305             warning (OPT_Wtraditional, "traditional C rejects initialization "
7306                      "of unions");
7307
7308           /* Accept a string constant to initialize a subarray.  */
7309           if (value.value != 0
7310               && fieldcode == ARRAY_TYPE
7311               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7312               && string_flag)
7313             value.value = orig_value;
7314           /* Otherwise, if we have come to a subaggregate,
7315              and we don't have an element of its type, push into it.  */
7316           else if (value.value != 0
7317                    && value.value != error_mark_node
7318                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7319                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7320                        || fieldcode == UNION_TYPE))
7321             {
7322               push_init_level (1);
7323               continue;
7324             }
7325
7326           if (value.value)
7327             {
7328               push_member_name (constructor_fields);
7329               output_init_element (value.value, strict_string,
7330                                    fieldtype, constructor_fields, 1, implicit);
7331               RESTORE_SPELLING_DEPTH (constructor_depth);
7332             }
7333           else
7334             /* Do the bookkeeping for an element that was
7335                directly output as a constructor.  */
7336             {
7337               constructor_bit_index = DECL_SIZE (constructor_fields);
7338               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7339             }
7340
7341           constructor_fields = 0;
7342         }
7343       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7344         {
7345           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7346           enum tree_code eltcode = TREE_CODE (elttype);
7347
7348           /* Accept a string constant to initialize a subarray.  */
7349           if (value.value != 0
7350               && eltcode == ARRAY_TYPE
7351               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
7352               && string_flag)
7353             value.value = orig_value;
7354           /* Otherwise, if we have come to a subaggregate,
7355              and we don't have an element of its type, push into it.  */
7356           else if (value.value != 0
7357                    && value.value != error_mark_node
7358                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
7359                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
7360                        || eltcode == UNION_TYPE))
7361             {
7362               push_init_level (1);
7363               continue;
7364             }
7365
7366           if (constructor_max_index != 0
7367               && (tree_int_cst_lt (constructor_max_index, constructor_index)
7368                   || integer_all_onesp (constructor_max_index)))
7369             {
7370               pedwarn_init (input_location, 0,
7371                             "excess elements in array initializer");
7372               break;
7373             }
7374
7375           /* Now output the actual element.  */
7376           if (value.value)
7377             {
7378               push_array_bounds (tree_low_cst (constructor_index, 1));
7379               output_init_element (value.value, strict_string,
7380                                    elttype, constructor_index, 1, implicit);
7381               RESTORE_SPELLING_DEPTH (constructor_depth);
7382             }
7383
7384           constructor_index
7385             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
7386
7387           if (!value.value)
7388             /* If we are doing the bookkeeping for an element that was
7389                directly output as a constructor, we must update
7390                constructor_unfilled_index.  */
7391             constructor_unfilled_index = constructor_index;
7392         }
7393       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
7394         {
7395           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7396
7397          /* Do a basic check of initializer size.  Note that vectors
7398             always have a fixed size derived from their type.  */
7399           if (tree_int_cst_lt (constructor_max_index, constructor_index))
7400             {
7401               pedwarn_init (input_location, 0,
7402                             "excess elements in vector initializer");
7403               break;
7404             }
7405
7406           /* Now output the actual element.  */
7407           if (value.value)
7408             output_init_element (value.value, strict_string,
7409                                  elttype, constructor_index, 1, implicit);
7410
7411           constructor_index
7412             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
7413
7414           if (!value.value)
7415             /* If we are doing the bookkeeping for an element that was
7416                directly output as a constructor, we must update
7417                constructor_unfilled_index.  */
7418             constructor_unfilled_index = constructor_index;
7419         }
7420
7421       /* Handle the sole element allowed in a braced initializer
7422          for a scalar variable.  */
7423       else if (constructor_type != error_mark_node
7424                && constructor_fields == 0)
7425         {
7426           pedwarn_init (input_location, 0,
7427                         "excess elements in scalar initializer");
7428           break;
7429         }
7430       else
7431         {
7432           if (value.value)
7433             output_init_element (value.value, strict_string,
7434                                  constructor_type, NULL_TREE, 1, implicit);
7435           constructor_fields = 0;
7436         }
7437
7438       /* Handle range initializers either at this level or anywhere higher
7439          in the designator stack.  */
7440       if (constructor_range_stack)
7441         {
7442           struct constructor_range_stack *p, *range_stack;
7443           int finish = 0;
7444
7445           range_stack = constructor_range_stack;
7446           constructor_range_stack = 0;
7447           while (constructor_stack != range_stack->stack)
7448             {
7449               gcc_assert (constructor_stack->implicit);
7450               process_init_element (pop_init_level (1), true);
7451             }
7452           for (p = range_stack;
7453                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
7454                p = p->prev)
7455             {
7456               gcc_assert (constructor_stack->implicit);
7457               process_init_element (pop_init_level (1), true);
7458             }
7459
7460           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
7461           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
7462             finish = 1;
7463
7464           while (1)
7465             {
7466               constructor_index = p->index;
7467               constructor_fields = p->fields;
7468               if (finish && p->range_end && p->index == p->range_start)
7469                 {
7470                   finish = 0;
7471                   p->prev = 0;
7472                 }
7473               p = p->next;
7474               if (!p)
7475                 break;
7476               push_init_level (2);
7477               p->stack = constructor_stack;
7478               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
7479                 p->index = p->range_start;
7480             }
7481
7482           if (!finish)
7483             constructor_range_stack = range_stack;
7484           continue;
7485         }
7486
7487       break;
7488     }
7489
7490   constructor_range_stack = 0;
7491 }
7492 \f
7493 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
7494    (guaranteed to be 'volatile' or null) and ARGS (represented using
7495    an ASM_EXPR node).  */
7496 tree
7497 build_asm_stmt (tree cv_qualifier, tree args)
7498 {
7499   if (!ASM_VOLATILE_P (args) && cv_qualifier)
7500     ASM_VOLATILE_P (args) = 1;
7501   return add_stmt (args);
7502 }
7503
7504 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
7505    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
7506    SIMPLE indicates whether there was anything at all after the
7507    string in the asm expression -- asm("blah") and asm("blah" : )
7508    are subtly different.  We use a ASM_EXPR node to represent this.  */
7509 tree
7510 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
7511                 bool simple)
7512 {
7513   tree tail;
7514   tree args;
7515   int i;
7516   const char *constraint;
7517   const char **oconstraints;
7518   bool allows_mem, allows_reg, is_inout;
7519   int ninputs, noutputs;
7520
7521   ninputs = list_length (inputs);
7522   noutputs = list_length (outputs);
7523   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
7524
7525   string = resolve_asm_operand_names (string, outputs, inputs);
7526
7527   /* Remove output conversions that change the type but not the mode.  */
7528   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
7529     {
7530       tree output = TREE_VALUE (tail);
7531
7532       /* ??? Really, this should not be here.  Users should be using a
7533          proper lvalue, dammit.  But there's a long history of using casts
7534          in the output operands.  In cases like longlong.h, this becomes a
7535          primitive form of typechecking -- if the cast can be removed, then
7536          the output operand had a type of the proper width; otherwise we'll
7537          get an error.  Gross, but ...  */
7538       STRIP_NOPS (output);
7539
7540       if (!lvalue_or_else (output, lv_asm))
7541         output = error_mark_node;
7542
7543       if (output != error_mark_node
7544           && (TREE_READONLY (output)
7545               || TYPE_READONLY (TREE_TYPE (output))
7546               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7547                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7548                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7549         readonly_error (output, lv_asm);
7550
7551       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7552       oconstraints[i] = constraint;
7553
7554       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7555                                    &allows_mem, &allows_reg, &is_inout))
7556         {
7557           /* If the operand is going to end up in memory,
7558              mark it addressable.  */
7559           if (!allows_reg && !c_mark_addressable (output))
7560             output = error_mark_node;
7561         }
7562       else
7563         output = error_mark_node;
7564
7565       TREE_VALUE (tail) = output;
7566     }
7567
7568   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7569     {
7570       tree input;
7571
7572       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7573       input = TREE_VALUE (tail);
7574
7575       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7576                                   oconstraints, &allows_mem, &allows_reg))
7577         {
7578           /* If the operand is going to end up in memory,
7579              mark it addressable.  */
7580           if (!allows_reg && allows_mem)
7581             {
7582               /* Strip the nops as we allow this case.  FIXME, this really
7583                  should be rejected or made deprecated.  */
7584               STRIP_NOPS (input);
7585               if (!c_mark_addressable (input))
7586                 input = error_mark_node;
7587           }
7588         }
7589       else
7590         input = error_mark_node;
7591
7592       TREE_VALUE (tail) = input;
7593     }
7594
7595   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7596
7597   /* asm statements without outputs, including simple ones, are treated
7598      as volatile.  */
7599   ASM_INPUT_P (args) = simple;
7600   ASM_VOLATILE_P (args) = (noutputs == 0);
7601
7602   return args;
7603 }
7604 \f
7605 /* Generate a goto statement to LABEL.  */
7606
7607 tree
7608 c_finish_goto_label (tree label)
7609 {
7610   tree decl = lookup_label (label);
7611   if (!decl)
7612     return NULL_TREE;
7613
7614   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7615     {
7616       error ("jump into statement expression");
7617       return NULL_TREE;
7618     }
7619
7620   if (C_DECL_UNJUMPABLE_VM (decl))
7621     {
7622       error ("jump into scope of identifier with variably modified type");
7623       return NULL_TREE;
7624     }
7625
7626   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7627     {
7628       /* No jump from outside this statement expression context, so
7629          record that there is a jump from within this context.  */
7630       struct c_label_list *nlist;
7631       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7632       nlist->next = label_context_stack_se->labels_used;
7633       nlist->label = decl;
7634       label_context_stack_se->labels_used = nlist;
7635     }
7636
7637   if (!C_DECL_UNDEFINABLE_VM (decl))
7638     {
7639       /* No jump from outside this context context of identifiers with
7640          variably modified type, so record that there is a jump from
7641          within this context.  */
7642       struct c_label_list *nlist;
7643       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7644       nlist->next = label_context_stack_vm->labels_used;
7645       nlist->label = decl;
7646       label_context_stack_vm->labels_used = nlist;
7647     }
7648
7649   TREE_USED (decl) = 1;
7650   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7651 }
7652
7653 /* Generate a computed goto statement to EXPR.  */
7654
7655 tree
7656 c_finish_goto_ptr (tree expr)
7657 {
7658   pedwarn (input_location, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
7659   expr = c_fully_fold (expr, false, NULL);
7660   expr = convert (ptr_type_node, expr);
7661   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7662 }
7663
7664 /* Generate a C `return' statement.  RETVAL is the expression for what
7665    to return, or a null pointer for `return;' with no value.  */
7666
7667 tree
7668 c_finish_return (tree retval)
7669 {
7670   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7671   bool no_warning = false;
7672   bool npc = false;
7673
7674   if (TREE_THIS_VOLATILE (current_function_decl))
7675     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7676
7677   if (retval)
7678     {
7679       tree semantic_type = NULL_TREE;
7680       npc = null_pointer_constant_p (retval);
7681       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
7682         {
7683           semantic_type = TREE_TYPE (retval);
7684           retval = TREE_OPERAND (retval, 0);
7685         }
7686       retval = c_fully_fold (retval, false, NULL);
7687       if (semantic_type)
7688         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
7689     }
7690
7691   if (!retval)
7692     {
7693       current_function_returns_null = 1;
7694       if ((warn_return_type || flag_isoc99)
7695           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7696         {
7697           pedwarn_c99 (input_location, flag_isoc99 ? 0 : OPT_Wreturn_type,
7698                        "%<return%> with no value, in "
7699                        "function returning non-void");
7700           no_warning = true;
7701         }
7702     }
7703   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7704     {
7705       current_function_returns_null = 1;
7706       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7707         pedwarn (input_location, 0,
7708                  "%<return%> with a value, in function returning void");
7709       else
7710         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
7711                  "%<return%> with expression, in function returning void");
7712     }
7713   else
7714     {
7715       tree t = convert_for_assignment (valtype, retval, ic_return, npc,
7716                                        NULL_TREE, NULL_TREE, 0);
7717       tree res = DECL_RESULT (current_function_decl);
7718       tree inner;
7719
7720       current_function_returns_value = 1;
7721       if (t == error_mark_node)
7722         return NULL_TREE;
7723
7724       inner = t = convert (TREE_TYPE (res), t);
7725
7726       /* Strip any conversions, additions, and subtractions, and see if
7727          we are returning the address of a local variable.  Warn if so.  */
7728       while (1)
7729         {
7730           switch (TREE_CODE (inner))
7731             {
7732             CASE_CONVERT:
7733             case NON_LVALUE_EXPR:
7734             case PLUS_EXPR:
7735             case POINTER_PLUS_EXPR:
7736               inner = TREE_OPERAND (inner, 0);
7737               continue;
7738
7739             case MINUS_EXPR:
7740               /* If the second operand of the MINUS_EXPR has a pointer
7741                  type (or is converted from it), this may be valid, so
7742                  don't give a warning.  */
7743               {
7744                 tree op1 = TREE_OPERAND (inner, 1);
7745
7746                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7747                        && (CONVERT_EXPR_P (op1)
7748                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7749                   op1 = TREE_OPERAND (op1, 0);
7750
7751                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7752                   break;
7753
7754                 inner = TREE_OPERAND (inner, 0);
7755                 continue;
7756               }
7757
7758             case ADDR_EXPR:
7759               inner = TREE_OPERAND (inner, 0);
7760
7761               while (REFERENCE_CLASS_P (inner)
7762                      && TREE_CODE (inner) != INDIRECT_REF)
7763                 inner = TREE_OPERAND (inner, 0);
7764
7765               if (DECL_P (inner)
7766                   && !DECL_EXTERNAL (inner)
7767                   && !TREE_STATIC (inner)
7768                   && DECL_CONTEXT (inner) == current_function_decl)
7769                 warning (0, "function returns address of local variable");
7770               break;
7771
7772             default:
7773               break;
7774             }
7775
7776           break;
7777         }
7778
7779       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7780
7781       if (warn_sequence_point)
7782         verify_sequence_points (retval);
7783     }
7784
7785   ret_stmt = build_stmt (RETURN_EXPR, retval);
7786   TREE_NO_WARNING (ret_stmt) |= no_warning;
7787   return add_stmt (ret_stmt);
7788 }
7789 \f
7790 struct c_switch {
7791   /* The SWITCH_EXPR being built.  */
7792   tree switch_expr;
7793
7794   /* The original type of the testing expression, i.e. before the
7795      default conversion is applied.  */
7796   tree orig_type;
7797
7798   /* A splay-tree mapping the low element of a case range to the high
7799      element, or NULL_TREE if there is no high element.  Used to
7800      determine whether or not a new case label duplicates an old case
7801      label.  We need a tree, rather than simply a hash table, because
7802      of the GNU case range extension.  */
7803   splay_tree cases;
7804
7805   /* Number of nested statement expressions within this switch
7806      statement; if nonzero, case and default labels may not
7807      appear.  */
7808   unsigned int blocked_stmt_expr;
7809
7810   /* Scope of outermost declarations of identifiers with variably
7811      modified type within this switch statement; if nonzero, case and
7812      default labels may not appear.  */
7813   unsigned int blocked_vm;
7814
7815   /* The next node on the stack.  */
7816   struct c_switch *next;
7817 };
7818
7819 /* A stack of the currently active switch statements.  The innermost
7820    switch statement is on the top of the stack.  There is no need to
7821    mark the stack for garbage collection because it is only active
7822    during the processing of the body of a function, and we never
7823    collect at that point.  */
7824
7825 struct c_switch *c_switch_stack;
7826
7827 /* Start a C switch statement, testing expression EXP.  Return the new
7828    SWITCH_EXPR.  */
7829
7830 tree
7831 c_start_case (tree exp)
7832 {
7833   tree orig_type = error_mark_node;
7834   struct c_switch *cs;
7835
7836   if (exp != error_mark_node)
7837     {
7838       orig_type = TREE_TYPE (exp);
7839
7840       if (!INTEGRAL_TYPE_P (orig_type))
7841         {
7842           if (orig_type != error_mark_node)
7843             {
7844               error ("switch quantity not an integer");
7845               orig_type = error_mark_node;
7846             }
7847           exp = integer_zero_node;
7848         }
7849       else
7850         {
7851           tree type = TYPE_MAIN_VARIANT (orig_type);
7852
7853           if (!in_system_header
7854               && (type == long_integer_type_node
7855                   || type == long_unsigned_type_node))
7856             warning (OPT_Wtraditional, "%<long%> switch expression not "
7857                      "converted to %<int%> in ISO C");
7858
7859           exp = c_fully_fold (exp, false, NULL);
7860           exp = default_conversion (exp);
7861
7862           if (warn_sequence_point)
7863             verify_sequence_points (exp);
7864         }
7865     }
7866
7867   /* Add this new SWITCH_EXPR to the stack.  */
7868   cs = XNEW (struct c_switch);
7869   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7870   cs->orig_type = orig_type;
7871   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7872   cs->blocked_stmt_expr = 0;
7873   cs->blocked_vm = 0;
7874   cs->next = c_switch_stack;
7875   c_switch_stack = cs;
7876
7877   return add_stmt (cs->switch_expr);
7878 }
7879
7880 /* Process a case label.  */
7881
7882 tree
7883 do_case (tree low_value, tree high_value)
7884 {
7885   tree label = NULL_TREE;
7886
7887   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
7888     {
7889       low_value = c_fully_fold (low_value, false, NULL);
7890       if (TREE_CODE (low_value) == INTEGER_CST)
7891         pedwarn (input_location, OPT_pedantic,
7892                  "case label is not an integer constant expression");
7893     }
7894
7895   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
7896     {
7897       high_value = c_fully_fold (high_value, false, NULL);
7898       if (TREE_CODE (high_value) == INTEGER_CST)
7899         pedwarn (input_location, OPT_pedantic,
7900                  "case label is not an integer constant expression");
7901     }
7902
7903   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7904       && !c_switch_stack->blocked_vm)
7905     {
7906       label = c_add_case_label (c_switch_stack->cases,
7907                                 SWITCH_COND (c_switch_stack->switch_expr),
7908                                 c_switch_stack->orig_type,
7909                                 low_value, high_value);
7910       if (label == error_mark_node)
7911         label = NULL_TREE;
7912     }
7913   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7914     {
7915       if (low_value)
7916         error ("case label in statement expression not containing "
7917                "enclosing switch statement");
7918       else
7919         error ("%<default%> label in statement expression not containing "
7920                "enclosing switch statement");
7921     }
7922   else if (c_switch_stack && c_switch_stack->blocked_vm)
7923     {
7924       if (low_value)
7925         error ("case label in scope of identifier with variably modified "
7926                "type not containing enclosing switch statement");
7927       else
7928         error ("%<default%> label in scope of identifier with variably "
7929                "modified type not containing enclosing switch statement");
7930     }
7931   else if (low_value)
7932     error ("case label not within a switch statement");
7933   else
7934     error ("%<default%> label not within a switch statement");
7935
7936   return label;
7937 }
7938
7939 /* Finish the switch statement.  */
7940
7941 void
7942 c_finish_case (tree body)
7943 {
7944   struct c_switch *cs = c_switch_stack;
7945   location_t switch_location;
7946
7947   SWITCH_BODY (cs->switch_expr) = body;
7948
7949   /* We must not be within a statement expression nested in the switch
7950      at this point; we might, however, be within the scope of an
7951      identifier with variably modified type nested in the switch.  */
7952   gcc_assert (!cs->blocked_stmt_expr);
7953
7954   /* Emit warnings as needed.  */
7955   if (EXPR_HAS_LOCATION (cs->switch_expr))
7956     switch_location = EXPR_LOCATION (cs->switch_expr);
7957   else
7958     switch_location = input_location;
7959   c_do_switch_warnings (cs->cases, switch_location,
7960                         TREE_TYPE (cs->switch_expr),
7961                         SWITCH_COND (cs->switch_expr));
7962
7963   /* Pop the stack.  */
7964   c_switch_stack = cs->next;
7965   splay_tree_delete (cs->cases);
7966   XDELETE (cs);
7967 }
7968 \f
7969 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7970    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7971    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7972    statement, and was not surrounded with parenthesis.  */
7973
7974 void
7975 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7976                   tree else_block, bool nested_if)
7977 {
7978   tree stmt;
7979
7980   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7981   if (warn_parentheses && nested_if && else_block == NULL)
7982     {
7983       tree inner_if = then_block;
7984
7985       /* We know from the grammar productions that there is an IF nested
7986          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7987          it might not be exactly THEN_BLOCK, but should be the last
7988          non-container statement within.  */
7989       while (1)
7990         switch (TREE_CODE (inner_if))
7991           {
7992           case COND_EXPR:
7993             goto found;
7994           case BIND_EXPR:
7995             inner_if = BIND_EXPR_BODY (inner_if);
7996             break;
7997           case STATEMENT_LIST:
7998             inner_if = expr_last (then_block);
7999             break;
8000           case TRY_FINALLY_EXPR:
8001           case TRY_CATCH_EXPR:
8002             inner_if = TREE_OPERAND (inner_if, 0);
8003             break;
8004           default:
8005             gcc_unreachable ();
8006           }
8007     found:
8008
8009       if (COND_EXPR_ELSE (inner_if))
8010          warning (OPT_Wparentheses,
8011                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
8012                   &if_locus);
8013     }
8014
8015   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8016   SET_EXPR_LOCATION (stmt, if_locus);
8017   add_stmt (stmt);
8018 }
8019
8020 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8021    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8022    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8023    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8024    the continue label.  Everything is allowed to be NULL.  */
8025
8026 void
8027 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8028                tree blab, tree clab, bool cond_is_first)
8029 {
8030   tree entry = NULL, exit = NULL, t;
8031
8032   /* If the condition is zero don't generate a loop construct.  */
8033   if (cond && integer_zerop (cond))
8034     {
8035       if (cond_is_first)
8036         {
8037           t = build_and_jump (&blab);
8038           SET_EXPR_LOCATION (t, start_locus);
8039           add_stmt (t);
8040         }
8041     }
8042   else
8043     {
8044       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8045
8046       /* If we have an exit condition, then we build an IF with gotos either
8047          out of the loop, or to the top of it.  If there's no exit condition,
8048          then we just build a jump back to the top.  */
8049       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
8050
8051       if (cond && !integer_nonzerop (cond))
8052         {
8053           /* Canonicalize the loop condition to the end.  This means
8054              generating a branch to the loop condition.  Reuse the
8055              continue label, if possible.  */
8056           if (cond_is_first)
8057             {
8058               if (incr || !clab)
8059                 {
8060                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8061                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
8062                 }
8063               else
8064                 t = build1 (GOTO_EXPR, void_type_node, clab);
8065               SET_EXPR_LOCATION (t, start_locus);
8066               add_stmt (t);
8067             }
8068
8069           t = build_and_jump (&blab);
8070           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
8071           if (cond_is_first)
8072             SET_EXPR_LOCATION (exit, start_locus);
8073           else
8074             SET_EXPR_LOCATION (exit, input_location);
8075         }
8076
8077       add_stmt (top);
8078     }
8079
8080   if (body)
8081     add_stmt (body);
8082   if (clab)
8083     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
8084   if (incr)
8085     add_stmt (incr);
8086   if (entry)
8087     add_stmt (entry);
8088   if (exit)
8089     add_stmt (exit);
8090   if (blab)
8091     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
8092 }
8093
8094 tree
8095 c_finish_bc_stmt (tree *label_p, bool is_break)
8096 {
8097   bool skip;
8098   tree label = *label_p;
8099
8100   /* In switch statements break is sometimes stylistically used after
8101      a return statement.  This can lead to spurious warnings about
8102      control reaching the end of a non-void function when it is
8103      inlined.  Note that we are calling block_may_fallthru with
8104      language specific tree nodes; this works because
8105      block_may_fallthru returns true when given something it does not
8106      understand.  */
8107   skip = !block_may_fallthru (cur_stmt_list);
8108
8109   if (!label)
8110     {
8111       if (!skip)
8112         *label_p = label = create_artificial_label ();
8113     }
8114   else if (TREE_CODE (label) == LABEL_DECL)
8115     ;
8116   else switch (TREE_INT_CST_LOW (label))
8117     {
8118     case 0:
8119       if (is_break)
8120         error ("break statement not within loop or switch");
8121       else
8122         error ("continue statement not within a loop");
8123       return NULL_TREE;
8124
8125     case 1:
8126       gcc_assert (is_break);
8127       error ("break statement used with OpenMP for loop");
8128       return NULL_TREE;
8129
8130     default:
8131       gcc_unreachable ();
8132     }
8133
8134   if (skip)
8135     return NULL_TREE;
8136
8137   if (!is_break)
8138     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
8139
8140   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
8141 }
8142
8143 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
8144
8145 static void
8146 emit_side_effect_warnings (tree expr)
8147 {
8148   if (expr == error_mark_node)
8149     ;
8150   else if (!TREE_SIDE_EFFECTS (expr))
8151     {
8152       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
8153         warning (OPT_Wunused_value, "%Hstatement with no effect",
8154                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
8155     }
8156   else
8157     warn_if_unused_value (expr, input_location);
8158 }
8159
8160 /* Process an expression as if it were a complete statement.  Emit
8161    diagnostics, but do not call ADD_STMT.  */
8162
8163 tree
8164 c_process_expr_stmt (tree expr)
8165 {
8166   if (!expr)
8167     return NULL_TREE;
8168
8169   expr = c_fully_fold (expr, false, NULL);
8170
8171   if (warn_sequence_point)
8172     verify_sequence_points (expr);
8173
8174   if (TREE_TYPE (expr) != error_mark_node
8175       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
8176       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
8177     error ("expression statement has incomplete type");
8178
8179   /* If we're not processing a statement expression, warn about unused values.
8180      Warnings for statement expressions will be emitted later, once we figure
8181      out which is the result.  */
8182   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8183       && warn_unused_value)
8184     emit_side_effect_warnings (expr);
8185
8186   /* If the expression is not of a type to which we cannot assign a line
8187      number, wrap the thing in a no-op NOP_EXPR.  */
8188   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
8189     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
8190
8191   if (CAN_HAVE_LOCATION_P (expr))
8192     SET_EXPR_LOCATION (expr, input_location);
8193
8194   return expr;
8195 }
8196
8197 /* Emit an expression as a statement.  */
8198
8199 tree
8200 c_finish_expr_stmt (tree expr)
8201 {
8202   if (expr)
8203     return add_stmt (c_process_expr_stmt (expr));
8204   else
8205     return NULL;
8206 }
8207
8208 /* Do the opposite and emit a statement as an expression.  To begin,
8209    create a new binding level and return it.  */
8210
8211 tree
8212 c_begin_stmt_expr (void)
8213 {
8214   tree ret;
8215   struct c_label_context_se *nstack;
8216   struct c_label_list *glist;
8217
8218   /* We must force a BLOCK for this level so that, if it is not expanded
8219      later, there is a way to turn off the entire subtree of blocks that
8220      are contained in it.  */
8221   keep_next_level ();
8222   ret = c_begin_compound_stmt (true);
8223   if (c_switch_stack)
8224     {
8225       c_switch_stack->blocked_stmt_expr++;
8226       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
8227     }
8228   for (glist = label_context_stack_se->labels_used;
8229        glist != NULL;
8230        glist = glist->next)
8231     {
8232       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
8233     }
8234   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
8235   nstack->labels_def = NULL;
8236   nstack->labels_used = NULL;
8237   nstack->next = label_context_stack_se;
8238   label_context_stack_se = nstack;
8239
8240   /* Mark the current statement list as belonging to a statement list.  */
8241   STATEMENT_LIST_STMT_EXPR (ret) = 1;
8242
8243   return ret;
8244 }
8245
8246 tree
8247 c_finish_stmt_expr (tree body)
8248 {
8249   tree last, type, tmp, val;
8250   tree *last_p;
8251   struct c_label_list *dlist, *glist, *glist_prev = NULL;
8252
8253   body = c_end_compound_stmt (body, true);
8254   if (c_switch_stack)
8255     {
8256       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
8257       c_switch_stack->blocked_stmt_expr--;
8258     }
8259   /* It is no longer possible to jump to labels defined within this
8260      statement expression.  */
8261   for (dlist = label_context_stack_se->labels_def;
8262        dlist != NULL;
8263        dlist = dlist->next)
8264     {
8265       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
8266     }
8267   /* It is again possible to define labels with a goto just outside
8268      this statement expression.  */
8269   for (glist = label_context_stack_se->next->labels_used;
8270        glist != NULL;
8271        glist = glist->next)
8272     {
8273       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
8274       glist_prev = glist;
8275     }
8276   if (glist_prev != NULL)
8277     glist_prev->next = label_context_stack_se->labels_used;
8278   else
8279     label_context_stack_se->next->labels_used
8280       = label_context_stack_se->labels_used;
8281   label_context_stack_se = label_context_stack_se->next;
8282
8283   /* Locate the last statement in BODY.  See c_end_compound_stmt
8284      about always returning a BIND_EXPR.  */
8285   last_p = &BIND_EXPR_BODY (body);
8286   last = BIND_EXPR_BODY (body);
8287
8288  continue_searching:
8289   if (TREE_CODE (last) == STATEMENT_LIST)
8290     {
8291       tree_stmt_iterator i;
8292
8293       /* This can happen with degenerate cases like ({ }).  No value.  */
8294       if (!TREE_SIDE_EFFECTS (last))
8295         return body;
8296
8297       /* If we're supposed to generate side effects warnings, process
8298          all of the statements except the last.  */
8299       if (warn_unused_value)
8300         {
8301           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
8302             emit_side_effect_warnings (tsi_stmt (i));
8303         }
8304       else
8305         i = tsi_last (last);
8306       last_p = tsi_stmt_ptr (i);
8307       last = *last_p;
8308     }
8309
8310   /* If the end of the list is exception related, then the list was split
8311      by a call to push_cleanup.  Continue searching.  */
8312   if (TREE_CODE (last) == TRY_FINALLY_EXPR
8313       || TREE_CODE (last) == TRY_CATCH_EXPR)
8314     {
8315       last_p = &TREE_OPERAND (last, 0);
8316       last = *last_p;
8317       goto continue_searching;
8318     }
8319
8320   /* In the case that the BIND_EXPR is not necessary, return the
8321      expression out from inside it.  */
8322   if (last == error_mark_node
8323       || (last == BIND_EXPR_BODY (body)
8324           && BIND_EXPR_VARS (body) == NULL))
8325     {
8326       /* Even if this looks constant, do not allow it in a constant
8327          expression.  */
8328       last = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (last), NULL_TREE, last);
8329       C_MAYBE_CONST_EXPR_NON_CONST (last) = 1;
8330       /* Do not warn if the return value of a statement expression is
8331          unused.  */
8332       TREE_NO_WARNING (last) = 1;
8333       return last;
8334     }
8335
8336   /* Extract the type of said expression.  */
8337   type = TREE_TYPE (last);
8338
8339   /* If we're not returning a value at all, then the BIND_EXPR that
8340      we already have is a fine expression to return.  */
8341   if (!type || VOID_TYPE_P (type))
8342     return body;
8343
8344   /* Now that we've located the expression containing the value, it seems
8345      silly to make voidify_wrapper_expr repeat the process.  Create a
8346      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
8347   tmp = create_tmp_var_raw (type, NULL);
8348
8349   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
8350      tree_expr_nonnegative_p giving up immediately.  */
8351   val = last;
8352   if (TREE_CODE (val) == NOP_EXPR
8353       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
8354     val = TREE_OPERAND (val, 0);
8355
8356   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
8357   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
8358
8359   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
8360 }
8361
8362 /* Begin the scope of an identifier of variably modified type, scope
8363    number SCOPE.  Jumping from outside this scope to inside it is not
8364    permitted.  */
8365
8366 void
8367 c_begin_vm_scope (unsigned int scope)
8368 {
8369   struct c_label_context_vm *nstack;
8370   struct c_label_list *glist;
8371
8372   gcc_assert (scope > 0);
8373
8374   /* At file_scope, we don't have to do any processing.  */
8375   if (label_context_stack_vm == NULL)
8376     return;
8377
8378   if (c_switch_stack && !c_switch_stack->blocked_vm)
8379     c_switch_stack->blocked_vm = scope;
8380   for (glist = label_context_stack_vm->labels_used;
8381        glist != NULL;
8382        glist = glist->next)
8383     {
8384       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
8385     }
8386   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
8387   nstack->labels_def = NULL;
8388   nstack->labels_used = NULL;
8389   nstack->scope = scope;
8390   nstack->next = label_context_stack_vm;
8391   label_context_stack_vm = nstack;
8392 }
8393
8394 /* End a scope which may contain identifiers of variably modified
8395    type, scope number SCOPE.  */
8396
8397 void
8398 c_end_vm_scope (unsigned int scope)
8399 {
8400   if (label_context_stack_vm == NULL)
8401     return;
8402   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
8403     c_switch_stack->blocked_vm = 0;
8404   /* We may have a number of nested scopes of identifiers with
8405      variably modified type, all at this depth.  Pop each in turn.  */
8406   while (label_context_stack_vm->scope == scope)
8407     {
8408       struct c_label_list *dlist, *glist, *glist_prev = NULL;
8409
8410       /* It is no longer possible to jump to labels defined within this
8411          scope.  */
8412       for (dlist = label_context_stack_vm->labels_def;
8413            dlist != NULL;
8414            dlist = dlist->next)
8415         {
8416           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
8417         }
8418       /* It is again possible to define labels with a goto just outside
8419          this scope.  */
8420       for (glist = label_context_stack_vm->next->labels_used;
8421            glist != NULL;
8422            glist = glist->next)
8423         {
8424           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
8425           glist_prev = glist;
8426         }
8427       if (glist_prev != NULL)
8428         glist_prev->next = label_context_stack_vm->labels_used;
8429       else
8430         label_context_stack_vm->next->labels_used
8431           = label_context_stack_vm->labels_used;
8432       label_context_stack_vm = label_context_stack_vm->next;
8433     }
8434 }
8435 \f
8436 /* Begin and end compound statements.  This is as simple as pushing
8437    and popping new statement lists from the tree.  */
8438
8439 tree
8440 c_begin_compound_stmt (bool do_scope)
8441 {
8442   tree stmt = push_stmt_list ();
8443   if (do_scope)
8444     push_scope ();
8445   return stmt;
8446 }
8447
8448 tree
8449 c_end_compound_stmt (tree stmt, bool do_scope)
8450 {
8451   tree block = NULL;
8452
8453   if (do_scope)
8454     {
8455       if (c_dialect_objc ())
8456         objc_clear_super_receiver ();
8457       block = pop_scope ();
8458     }
8459
8460   stmt = pop_stmt_list (stmt);
8461   stmt = c_build_bind_expr (block, stmt);
8462
8463   /* If this compound statement is nested immediately inside a statement
8464      expression, then force a BIND_EXPR to be created.  Otherwise we'll
8465      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
8466      STATEMENT_LISTs merge, and thus we can lose track of what statement
8467      was really last.  */
8468   if (cur_stmt_list
8469       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8470       && TREE_CODE (stmt) != BIND_EXPR)
8471     {
8472       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
8473       TREE_SIDE_EFFECTS (stmt) = 1;
8474     }
8475
8476   return stmt;
8477 }
8478
8479 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
8480    when the current scope is exited.  EH_ONLY is true when this is not
8481    meant to apply to normal control flow transfer.  */
8482
8483 void
8484 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
8485 {
8486   enum tree_code code;
8487   tree stmt, list;
8488   bool stmt_expr;
8489
8490   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
8491   stmt = build_stmt (code, NULL, cleanup);
8492   add_stmt (stmt);
8493   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
8494   list = push_stmt_list ();
8495   TREE_OPERAND (stmt, 0) = list;
8496   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
8497 }
8498 \f
8499 /* Build a binary-operation expression without default conversions.
8500    CODE is the kind of expression to build.
8501    LOCATION is the operator's location.
8502    This function differs from `build' in several ways:
8503    the data type of the result is computed and recorded in it,
8504    warnings are generated if arg data types are invalid,
8505    special handling for addition and subtraction of pointers is known,
8506    and some optimization is done (operations on narrow ints
8507    are done in the narrower type when that gives the same result).
8508    Constant folding is also done before the result is returned.
8509
8510    Note that the operands will never have enumeral types, or function
8511    or array types, because either they will have the default conversions
8512    performed or they have both just been converted to some other type in which
8513    the arithmetic is to be done.  */
8514
8515 tree
8516 build_binary_op (location_t location, enum tree_code code,
8517                  tree orig_op0, tree orig_op1, int convert_p)
8518 {
8519   tree type0, type1, orig_type0, orig_type1;
8520   tree eptype;
8521   enum tree_code code0, code1;
8522   tree op0, op1;
8523   tree ret = error_mark_node;
8524   const char *invalid_op_diag;
8525   bool op0_int_operands, op1_int_operands;
8526   bool int_const, int_const_or_overflow, int_operands;
8527
8528   /* Expression code to give to the expression when it is built.
8529      Normally this is CODE, which is what the caller asked for,
8530      but in some special cases we change it.  */
8531   enum tree_code resultcode = code;
8532
8533   /* Data type in which the computation is to be performed.
8534      In the simplest cases this is the common type of the arguments.  */
8535   tree result_type = NULL;
8536
8537   /* When the computation is in excess precision, the type of the
8538      final EXCESS_PRECISION_EXPR.  */
8539   tree real_result_type = NULL;
8540
8541   /* Nonzero means operands have already been type-converted
8542      in whatever way is necessary.
8543      Zero means they need to be converted to RESULT_TYPE.  */
8544   int converted = 0;
8545
8546   /* Nonzero means create the expression with this type, rather than
8547      RESULT_TYPE.  */
8548   tree build_type = 0;
8549
8550   /* Nonzero means after finally constructing the expression
8551      convert it to this type.  */
8552   tree final_type = 0;
8553
8554   /* Nonzero if this is an operation like MIN or MAX which can
8555      safely be computed in short if both args are promoted shorts.
8556      Also implies COMMON.
8557      -1 indicates a bitwise operation; this makes a difference
8558      in the exact conditions for when it is safe to do the operation
8559      in a narrower mode.  */
8560   int shorten = 0;
8561
8562   /* Nonzero if this is a comparison operation;
8563      if both args are promoted shorts, compare the original shorts.
8564      Also implies COMMON.  */
8565   int short_compare = 0;
8566
8567   /* Nonzero if this is a right-shift operation, which can be computed on the
8568      original short and then promoted if the operand is a promoted short.  */
8569   int short_shift = 0;
8570
8571   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
8572   int common = 0;
8573
8574   /* True means types are compatible as far as ObjC is concerned.  */
8575   bool objc_ok;
8576
8577   /* True means this is an arithmetic operation that may need excess
8578      precision.  */
8579   bool may_need_excess_precision;
8580
8581   if (location == UNKNOWN_LOCATION)
8582     location = input_location;
8583
8584   op0 = orig_op0;
8585   op1 = orig_op1;
8586
8587   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
8588   if (op0_int_operands)
8589     op0 = remove_c_maybe_const_expr (op0);
8590   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
8591   if (op1_int_operands)
8592     op1 = remove_c_maybe_const_expr (op1);
8593   int_operands = (op0_int_operands && op1_int_operands);
8594   if (int_operands)
8595     {
8596       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
8597                                && TREE_CODE (orig_op1) == INTEGER_CST);
8598       int_const = (int_const_or_overflow
8599                    && !TREE_OVERFLOW (orig_op0)
8600                    && !TREE_OVERFLOW (orig_op1));
8601     }
8602   else
8603     int_const = int_const_or_overflow = false;
8604
8605   if (convert_p)
8606     {
8607       op0 = default_conversion (op0);
8608       op1 = default_conversion (op1);
8609     }
8610
8611   orig_type0 = type0 = TREE_TYPE (op0);
8612   orig_type1 = type1 = TREE_TYPE (op1);
8613
8614   /* The expression codes of the data types of the arguments tell us
8615      whether the arguments are integers, floating, pointers, etc.  */
8616   code0 = TREE_CODE (type0);
8617   code1 = TREE_CODE (type1);
8618
8619   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
8620   STRIP_TYPE_NOPS (op0);
8621   STRIP_TYPE_NOPS (op1);
8622
8623   /* If an error was already reported for one of the arguments,
8624      avoid reporting another error.  */
8625
8626   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8627     return error_mark_node;
8628
8629   if ((invalid_op_diag
8630        = targetm.invalid_binary_op (code, type0, type1)))
8631     {
8632       error_at (location, invalid_op_diag);
8633       return error_mark_node;
8634     }
8635
8636   switch (code)
8637     {
8638     case PLUS_EXPR:
8639     case MINUS_EXPR:
8640     case MULT_EXPR:
8641     case TRUNC_DIV_EXPR:
8642     case CEIL_DIV_EXPR:
8643     case FLOOR_DIV_EXPR:
8644     case ROUND_DIV_EXPR:
8645     case EXACT_DIV_EXPR:
8646       may_need_excess_precision = true;
8647       break;
8648     default:
8649       may_need_excess_precision = false;
8650       break;
8651     }
8652   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
8653     {
8654       op0 = TREE_OPERAND (op0, 0);
8655       type0 = TREE_TYPE (op0);
8656     }
8657   else if (may_need_excess_precision
8658            && (eptype = excess_precision_type (type0)) != NULL_TREE)
8659     {
8660       type0 = eptype;
8661       op0 = convert (eptype, op0);
8662     }
8663   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
8664     {
8665       op1 = TREE_OPERAND (op1, 0);
8666       type1 = TREE_TYPE (op1);
8667     }
8668   else if (may_need_excess_precision
8669            && (eptype = excess_precision_type (type1)) != NULL_TREE)
8670     {
8671       type1 = eptype;
8672       op1 = convert (eptype, op1);
8673     }
8674
8675   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8676
8677   switch (code)
8678     {
8679     case PLUS_EXPR:
8680       /* Handle the pointer + int case.  */
8681       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8682         {
8683           ret = pointer_int_sum (location, PLUS_EXPR, op0, op1);
8684           goto return_build_binary_op;
8685         }
8686       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8687         {
8688           ret = pointer_int_sum (location, PLUS_EXPR, op1, op0);
8689           goto return_build_binary_op;
8690         }
8691       else
8692         common = 1;
8693       break;
8694
8695     case MINUS_EXPR:
8696       /* Subtraction of two similar pointers.
8697          We must subtract them as integers, then divide by object size.  */
8698       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8699           && comp_target_types (type0, type1))
8700         {
8701           ret = pointer_diff (op0, op1);
8702           goto return_build_binary_op;
8703         }
8704       /* Handle pointer minus int.  Just like pointer plus int.  */
8705       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8706         {
8707           ret = pointer_int_sum (location, MINUS_EXPR, op0, op1);
8708           goto return_build_binary_op;
8709         }
8710       else
8711         common = 1;
8712       break;
8713
8714     case MULT_EXPR:
8715       common = 1;
8716       break;
8717
8718     case TRUNC_DIV_EXPR:
8719     case CEIL_DIV_EXPR:
8720     case FLOOR_DIV_EXPR:
8721     case ROUND_DIV_EXPR:
8722     case EXACT_DIV_EXPR:
8723       warn_for_div_by_zero (location, op1);
8724
8725       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8726            || code0 == FIXED_POINT_TYPE
8727            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8728           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8729               || code1 == FIXED_POINT_TYPE
8730               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8731         {
8732           enum tree_code tcode0 = code0, tcode1 = code1;
8733
8734           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8735             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8736           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8737             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8738
8739           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8740               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8741             resultcode = RDIV_EXPR;
8742           else
8743             /* Although it would be tempting to shorten always here, that
8744                loses on some targets, since the modulo instruction is
8745                undefined if the quotient can't be represented in the
8746                computation mode.  We shorten only if unsigned or if
8747                dividing by something we know != -1.  */
8748             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8749                        || (TREE_CODE (op1) == INTEGER_CST
8750                            && !integer_all_onesp (op1)));
8751           common = 1;
8752         }
8753       break;
8754
8755     case BIT_AND_EXPR:
8756     case BIT_IOR_EXPR:
8757     case BIT_XOR_EXPR:
8758       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8759         shorten = -1;
8760       /* Allow vector types which are not floating point types.   */
8761       else if (code0 == VECTOR_TYPE
8762                && code1 == VECTOR_TYPE
8763                && !VECTOR_FLOAT_TYPE_P (type0)
8764                && !VECTOR_FLOAT_TYPE_P (type1))
8765         common = 1;
8766       break;
8767
8768     case TRUNC_MOD_EXPR:
8769     case FLOOR_MOD_EXPR:
8770       warn_for_div_by_zero (location, op1);
8771
8772       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8773         {
8774           /* Although it would be tempting to shorten always here, that loses
8775              on some targets, since the modulo instruction is undefined if the
8776              quotient can't be represented in the computation mode.  We shorten
8777              only if unsigned or if dividing by something we know != -1.  */
8778           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8779                      || (TREE_CODE (op1) == INTEGER_CST
8780                          && !integer_all_onesp (op1)));
8781           common = 1;
8782         }
8783       break;
8784
8785     case TRUTH_ANDIF_EXPR:
8786     case TRUTH_ORIF_EXPR:
8787     case TRUTH_AND_EXPR:
8788     case TRUTH_OR_EXPR:
8789     case TRUTH_XOR_EXPR:
8790       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8791            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8792            || code0 == FIXED_POINT_TYPE)
8793           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8794               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8795               || code1 == FIXED_POINT_TYPE))
8796         {
8797           /* Result of these operations is always an int,
8798              but that does not mean the operands should be
8799              converted to ints!  */
8800           result_type = integer_type_node;
8801           op0 = c_common_truthvalue_conversion (location, op0);
8802           op1 = c_common_truthvalue_conversion (location, op1);
8803           converted = 1;
8804         }
8805       if (code == TRUTH_ANDIF_EXPR)
8806         {
8807           int_const_or_overflow = (int_operands
8808                                    && TREE_CODE (orig_op0) == INTEGER_CST
8809                                    && (op0 == truthvalue_false_node
8810                                        || TREE_CODE (orig_op1) == INTEGER_CST));
8811           int_const = (int_const_or_overflow
8812                        && !TREE_OVERFLOW (orig_op0)
8813                        && (op0 == truthvalue_false_node
8814                            || !TREE_OVERFLOW (orig_op1)));
8815         }
8816       else if (code == TRUTH_ORIF_EXPR)
8817         {
8818           int_const_or_overflow = (int_operands
8819                                    && TREE_CODE (orig_op0) == INTEGER_CST
8820                                    && (op0 == truthvalue_true_node
8821                                        || TREE_CODE (orig_op1) == INTEGER_CST));
8822           int_const = (int_const_or_overflow
8823                        && !TREE_OVERFLOW (orig_op0)
8824                        && (op0 == truthvalue_true_node
8825                            || !TREE_OVERFLOW (orig_op1)));
8826         }
8827       break;
8828
8829       /* Shift operations: result has same type as first operand;
8830          always convert second operand to int.
8831          Also set SHORT_SHIFT if shifting rightward.  */
8832
8833     case RSHIFT_EXPR:
8834       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8835           && code1 == INTEGER_TYPE)
8836         {
8837           if (TREE_CODE (op1) == INTEGER_CST)
8838             {
8839               if (tree_int_cst_sgn (op1) < 0)
8840                 {
8841                   int_const = false;
8842                   if (skip_evaluation == 0)
8843                     warning (0, "right shift count is negative");
8844                 }
8845               else
8846                 {
8847                   if (!integer_zerop (op1))
8848                     short_shift = 1;
8849
8850                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8851                     {
8852                       int_const = false;
8853                       if (skip_evaluation == 0)
8854                         warning (0, "right shift count >= width of type");
8855                     }
8856                 }
8857             }
8858
8859           /* Use the type of the value to be shifted.  */
8860           result_type = type0;
8861           /* Convert the shift-count to an integer, regardless of size
8862              of value being shifted.  */
8863           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8864             op1 = convert (integer_type_node, op1);
8865           /* Avoid converting op1 to result_type later.  */
8866           converted = 1;
8867         }
8868       break;
8869
8870     case LSHIFT_EXPR:
8871       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8872           && code1 == INTEGER_TYPE)
8873         {
8874           if (TREE_CODE (op1) == INTEGER_CST)
8875             {
8876               if (tree_int_cst_sgn (op1) < 0)
8877                 {
8878                   int_const = false;
8879                   if (skip_evaluation == 0)
8880                     warning (0, "left shift count is negative");
8881                 }
8882
8883               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8884                 {
8885                   int_const = false;
8886                   if (skip_evaluation == 0)
8887                     warning (0, "left shift count >= width of type");
8888                 }
8889             }
8890
8891           /* Use the type of the value to be shifted.  */
8892           result_type = type0;
8893           /* Convert the shift-count to an integer, regardless of size
8894              of value being shifted.  */
8895           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8896             op1 = convert (integer_type_node, op1);
8897           /* Avoid converting op1 to result_type later.  */
8898           converted = 1;
8899         }
8900       break;
8901
8902     case EQ_EXPR:
8903     case NE_EXPR:
8904       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8905         warning_at (location,
8906                     OPT_Wfloat_equal,
8907                     "comparing floating point with == or != is unsafe");
8908       /* Result of comparison is always int,
8909          but don't convert the args to int!  */
8910       build_type = integer_type_node;
8911       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8912            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8913           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8914               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8915         short_compare = 1;
8916       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8917         {
8918           tree tt0 = TREE_TYPE (type0);
8919           tree tt1 = TREE_TYPE (type1);
8920           /* Anything compares with void *.  void * compares with anything.
8921              Otherwise, the targets must be compatible
8922              and both must be object or both incomplete.  */
8923           if (comp_target_types (type0, type1))
8924             result_type = common_pointer_type (type0, type1);
8925           else if (VOID_TYPE_P (tt0))
8926             {
8927               /* op0 != orig_op0 detects the case of something
8928                  whose value is 0 but which isn't a valid null ptr const.  */
8929               if (pedantic && !null_pointer_constant_p (orig_op0)
8930                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8931                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8932                          "comparison of %<void *%> with function pointer");
8933             }
8934           else if (VOID_TYPE_P (tt1))
8935             {
8936               if (pedantic && !null_pointer_constant_p (orig_op1)
8937                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8938                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8939                          "comparison of %<void *%> with function pointer");
8940             }
8941           else
8942             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8943             if (!objc_ok)
8944               pedwarn (location, 0,
8945                        "comparison of distinct pointer types lacks a cast");
8946
8947           if (result_type == NULL_TREE)
8948             result_type = ptr_type_node;
8949         }
8950       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8951         {
8952           if (TREE_CODE (op0) == ADDR_EXPR
8953               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8954             warning_at (location,
8955                         OPT_Waddress, "the address of %qD will never be NULL",
8956                         TREE_OPERAND (op0, 0));
8957           result_type = type0;
8958         }
8959       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8960         {
8961           if (TREE_CODE (op1) == ADDR_EXPR
8962               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8963             warning_at (location,
8964                         OPT_Waddress, "the address of %qD will never be NULL",
8965                         TREE_OPERAND (op1, 0));
8966           result_type = type1;
8967         }
8968       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8969         {
8970           result_type = type0;
8971           pedwarn (location, 0, "comparison between pointer and integer");
8972         }
8973       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8974         {
8975           result_type = type1;
8976           pedwarn (location, 0, "comparison between pointer and integer");
8977         }
8978       break;
8979
8980     case LE_EXPR:
8981     case GE_EXPR:
8982     case LT_EXPR:
8983     case GT_EXPR:
8984       build_type = integer_type_node;
8985       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8986            || code0 == FIXED_POINT_TYPE)
8987           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8988               || code1 == FIXED_POINT_TYPE))
8989         short_compare = 1;
8990       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8991         {
8992           if (comp_target_types (type0, type1))
8993             {
8994               result_type = common_pointer_type (type0, type1);
8995               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8996                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8997                 pedwarn (location, 0,
8998                          "comparison of complete and incomplete pointers");
8999               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9000                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9001                          "ordered comparisons of pointers to functions");
9002             }
9003           else
9004             {
9005               result_type = ptr_type_node;
9006               pedwarn (location, 0,
9007                        "comparison of distinct pointer types lacks a cast");
9008             }
9009         }
9010       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9011         {
9012           result_type = type0;
9013           if (pedantic)
9014             pedwarn (location, OPT_pedantic,
9015                      "ordered comparison of pointer with integer zero");
9016           else if (extra_warnings)
9017             warning_at (location, OPT_Wextra,
9018                      "ordered comparison of pointer with integer zero");
9019         }
9020       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9021         {
9022           result_type = type1;
9023           pedwarn (location, OPT_pedantic,
9024                    "ordered comparison of pointer with integer zero");
9025         }
9026       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9027         {
9028           result_type = type0;
9029           pedwarn (location, 0, "comparison between pointer and integer");
9030         }
9031       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9032         {
9033           result_type = type1;
9034           pedwarn (location, 0, "comparison between pointer and integer");
9035         }
9036       break;
9037
9038     default:
9039       gcc_unreachable ();
9040     }
9041
9042   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9043     return error_mark_node;
9044
9045   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9046       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
9047           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
9048                                                     TREE_TYPE (type1))))
9049     {
9050       binary_op_error (location, code, type0, type1);
9051       return error_mark_node;
9052     }
9053
9054   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9055        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
9056       &&
9057       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9058        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
9059     {
9060       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
9061
9062       if (shorten || common || short_compare)
9063         {
9064           result_type = c_common_type (type0, type1);
9065           if (result_type == error_mark_node)
9066             return error_mark_node;
9067         }
9068
9069       /* For certain operations (which identify themselves by shorten != 0)
9070          if both args were extended from the same smaller type,
9071          do the arithmetic in that type and then extend.
9072
9073          shorten !=0 and !=1 indicates a bitwise operation.
9074          For them, this optimization is safe only if
9075          both args are zero-extended or both are sign-extended.
9076          Otherwise, we might change the result.
9077          Eg, (short)-1 | (unsigned short)-1 is (int)-1
9078          but calculated in (unsigned short) it would be (unsigned short)-1.  */
9079
9080       if (shorten && none_complex)
9081         {
9082           final_type = result_type;
9083           result_type = shorten_binary_op (result_type, op0, op1,
9084                                            shorten == -1);
9085         }
9086
9087       /* Shifts can be shortened if shifting right.  */
9088
9089       if (short_shift)
9090         {
9091           int unsigned_arg;
9092           tree arg0 = get_narrower (op0, &unsigned_arg);
9093
9094           final_type = result_type;
9095
9096           if (arg0 == op0 && final_type == TREE_TYPE (op0))
9097             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
9098
9099           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
9100               /* We can shorten only if the shift count is less than the
9101                  number of bits in the smaller type size.  */
9102               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
9103               /* We cannot drop an unsigned shift after sign-extension.  */
9104               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
9105             {
9106               /* Do an unsigned shift if the operand was zero-extended.  */
9107               result_type
9108                 = c_common_signed_or_unsigned_type (unsigned_arg,
9109                                                     TREE_TYPE (arg0));
9110               /* Convert value-to-be-shifted to that type.  */
9111               if (TREE_TYPE (op0) != result_type)
9112                 op0 = convert (result_type, op0);
9113               converted = 1;
9114             }
9115         }
9116
9117       /* Comparison operations are shortened too but differently.
9118          They identify themselves by setting short_compare = 1.  */
9119
9120       if (short_compare)
9121         {
9122           /* Don't write &op0, etc., because that would prevent op0
9123              from being kept in a register.
9124              Instead, make copies of the our local variables and
9125              pass the copies by reference, then copy them back afterward.  */
9126           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
9127           enum tree_code xresultcode = resultcode;
9128           tree val
9129             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
9130
9131           if (val != 0)
9132             {
9133               ret = val;
9134               goto return_build_binary_op;
9135             }
9136
9137           op0 = xop0, op1 = xop1;
9138           converted = 1;
9139           resultcode = xresultcode;
9140
9141           if (!skip_evaluation)
9142             {
9143               bool op0_maybe_const = true;
9144               bool op1_maybe_const = true;
9145               tree orig_op0_folded, orig_op1_folded;
9146
9147               if (in_late_binary_op)
9148                 {
9149                   orig_op0_folded = orig_op0;
9150                   orig_op1_folded = orig_op1;
9151                 }
9152               else
9153                 {
9154                   /* Fold for the sake of possible warnings, as in
9155                      build_conditional_expr.  This requires the
9156                      "original" values to be folded, not just op0 and
9157                      op1.  */
9158                   op0 = c_fully_fold (op0, require_constant_value,
9159                                       &op0_maybe_const);
9160                   op1 = c_fully_fold (op1, require_constant_value,
9161                                       &op1_maybe_const);
9162                   orig_op0_folded = c_fully_fold (orig_op0,
9163                                                   require_constant_value,
9164                                                   NULL);
9165                   orig_op1_folded = c_fully_fold (orig_op1,
9166                                                   require_constant_value,
9167                                                   NULL);
9168                 }
9169
9170               if (warn_sign_compare)
9171                 warn_for_sign_compare (location, orig_op0_folded,
9172                                        orig_op1_folded, op0, op1,
9173                                        result_type, resultcode);
9174               if (!in_late_binary_op)
9175                 {
9176                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
9177                     {
9178                       op0 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op0),
9179                                     NULL, op0);
9180                       C_MAYBE_CONST_EXPR_NON_CONST (op0) = !op0_maybe_const;
9181                     }
9182                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
9183                     {
9184                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
9185                                     NULL, op1);
9186                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
9187                     }
9188                 }
9189             }
9190         }
9191     }
9192
9193   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
9194      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
9195      Then the expression will be built.
9196      It will be given type FINAL_TYPE if that is nonzero;
9197      otherwise, it will be given type RESULT_TYPE.  */
9198
9199   if (!result_type)
9200     {
9201       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
9202       return error_mark_node;
9203     }
9204
9205   if (!converted)
9206     {
9207       if (TREE_TYPE (op0) != result_type)
9208         op0 = convert_and_check (result_type, op0);
9209       if (TREE_TYPE (op1) != result_type)
9210         op1 = convert_and_check (result_type, op1);
9211
9212       /* This can happen if one operand has a vector type, and the other
9213          has a different type.  */
9214       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9215         return error_mark_node;
9216     }
9217
9218   if (build_type == NULL_TREE)
9219     {
9220       build_type = result_type;
9221       if (type0 != orig_type0 || type1 != orig_type1)
9222         {
9223           gcc_assert (may_need_excess_precision && common);
9224           real_result_type = c_common_type (orig_type0, orig_type1);
9225         }
9226     }
9227
9228   /* Treat expressions in initializers specially as they can't trap.  */
9229   if (int_const_or_overflow)
9230     ret = (require_constant_value
9231            ? fold_build2_initializer (resultcode, build_type, op0, op1)
9232            : fold_build2 (resultcode, build_type, op0, op1));
9233   else
9234     ret = build2 (resultcode, build_type, op0, op1);
9235   if (final_type != 0)
9236     ret = convert (final_type, ret);
9237
9238  return_build_binary_op:
9239   gcc_assert (ret != error_mark_node);
9240   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
9241     ret = (int_operands
9242            ? note_integer_operands (ret)
9243            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
9244   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
9245            && !in_late_binary_op)
9246     ret = note_integer_operands (ret);
9247   if (real_result_type)
9248     ret = build1 (EXCESS_PRECISION_EXPR, real_result_type, ret);
9249   protected_set_expr_location (ret, location);
9250   return ret;
9251 }
9252
9253
9254 /* Convert EXPR to be a truth-value, validating its type for this
9255    purpose.  LOCATION is the source location for the expression.  */
9256
9257 tree
9258 c_objc_common_truthvalue_conversion (location_t location, tree expr)
9259 {
9260   bool int_const, int_operands;
9261
9262   switch (TREE_CODE (TREE_TYPE (expr)))
9263     {
9264     case ARRAY_TYPE:
9265       error_at (location, "used array that cannot be converted to pointer where scalar is required");
9266       return error_mark_node;
9267
9268     case RECORD_TYPE:
9269       error_at (location, "used struct type value where scalar is required");
9270       return error_mark_node;
9271
9272     case UNION_TYPE:
9273       error_at (location, "used union type value where scalar is required");
9274       return error_mark_node;
9275
9276     case FUNCTION_TYPE:
9277       gcc_unreachable ();
9278
9279     default:
9280       break;
9281     }
9282
9283   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
9284   int_operands = EXPR_INT_CONST_OPERANDS (expr);
9285   if (int_operands)
9286     expr = remove_c_maybe_const_expr (expr);
9287
9288   /* ??? Should we also give an error for void and vectors rather than
9289      leaving those to give errors later?  */
9290   expr = c_common_truthvalue_conversion (location, expr);
9291
9292   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
9293     {
9294       if (TREE_OVERFLOW (expr))
9295         return expr;
9296       else
9297         return note_integer_operands (expr);
9298     }
9299   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
9300     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9301   return expr;
9302 }
9303 \f
9304
9305 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
9306    required.  */
9307
9308 tree
9309 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
9310 {
9311   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
9312     {
9313       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
9314       /* Executing a compound literal inside a function reinitializes
9315          it.  */
9316       if (!TREE_STATIC (decl))
9317         *se = true;
9318       return decl;
9319     }
9320   else
9321     return expr;
9322 }
9323 \f
9324 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9325
9326 tree
9327 c_begin_omp_parallel (void)
9328 {
9329   tree block;
9330
9331   keep_next_level ();
9332   block = c_begin_compound_stmt (true);
9333
9334   return block;
9335 }
9336
9337 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
9338
9339 tree
9340 c_finish_omp_parallel (tree clauses, tree block)
9341 {
9342   tree stmt;
9343
9344   block = c_end_compound_stmt (block, true);
9345
9346   stmt = make_node (OMP_PARALLEL);
9347   TREE_TYPE (stmt) = void_type_node;
9348   OMP_PARALLEL_CLAUSES (stmt) = clauses;
9349   OMP_PARALLEL_BODY (stmt) = block;
9350
9351   return add_stmt (stmt);
9352 }
9353
9354 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9355
9356 tree
9357 c_begin_omp_task (void)
9358 {
9359   tree block;
9360
9361   keep_next_level ();
9362   block = c_begin_compound_stmt (true);
9363
9364   return block;
9365 }
9366
9367 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
9368
9369 tree
9370 c_finish_omp_task (tree clauses, tree block)
9371 {
9372   tree stmt;
9373
9374   block = c_end_compound_stmt (block, true);
9375
9376   stmt = make_node (OMP_TASK);
9377   TREE_TYPE (stmt) = void_type_node;
9378   OMP_TASK_CLAUSES (stmt) = clauses;
9379   OMP_TASK_BODY (stmt) = block;
9380
9381   return add_stmt (stmt);
9382 }
9383
9384 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
9385    Remove any elements from the list that are invalid.  */
9386
9387 tree
9388 c_finish_omp_clauses (tree clauses)
9389 {
9390   bitmap_head generic_head, firstprivate_head, lastprivate_head;
9391   tree c, t, *pc = &clauses;
9392   const char *name;
9393
9394   bitmap_obstack_initialize (NULL);
9395   bitmap_initialize (&generic_head, &bitmap_default_obstack);
9396   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
9397   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
9398
9399   for (pc = &clauses, c = clauses; c ; c = *pc)
9400     {
9401       bool remove = false;
9402       bool need_complete = false;
9403       bool need_implicitly_determined = false;
9404
9405       switch (OMP_CLAUSE_CODE (c))
9406         {
9407         case OMP_CLAUSE_SHARED:
9408           name = "shared";
9409           need_implicitly_determined = true;
9410           goto check_dup_generic;
9411
9412         case OMP_CLAUSE_PRIVATE:
9413           name = "private";
9414           need_complete = true;
9415           need_implicitly_determined = true;
9416           goto check_dup_generic;
9417
9418         case OMP_CLAUSE_REDUCTION:
9419           name = "reduction";
9420           need_implicitly_determined = true;
9421           t = OMP_CLAUSE_DECL (c);
9422           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
9423               || POINTER_TYPE_P (TREE_TYPE (t)))
9424             {
9425               error ("%qE has invalid type for %<reduction%>", t);
9426               remove = true;
9427             }
9428           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
9429             {
9430               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
9431               const char *r_name = NULL;
9432
9433               switch (r_code)
9434                 {
9435                 case PLUS_EXPR:
9436                 case MULT_EXPR:
9437                 case MINUS_EXPR:
9438                   break;
9439                 case BIT_AND_EXPR:
9440                   r_name = "&";
9441                   break;
9442                 case BIT_XOR_EXPR:
9443                   r_name = "^";
9444                   break;
9445                 case BIT_IOR_EXPR:
9446                   r_name = "|";
9447                   break;
9448                 case TRUTH_ANDIF_EXPR:
9449                   r_name = "&&";
9450                   break;
9451                 case TRUTH_ORIF_EXPR:
9452                   r_name = "||";
9453                   break;
9454                 default:
9455                   gcc_unreachable ();
9456                 }
9457               if (r_name)
9458                 {
9459                   error ("%qE has invalid type for %<reduction(%s)%>",
9460                          t, r_name);
9461                   remove = true;
9462                 }
9463             }
9464           goto check_dup_generic;
9465
9466         case OMP_CLAUSE_COPYPRIVATE:
9467           name = "copyprivate";
9468           goto check_dup_generic;
9469
9470         case OMP_CLAUSE_COPYIN:
9471           name = "copyin";
9472           t = OMP_CLAUSE_DECL (c);
9473           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
9474             {
9475               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
9476               remove = true;
9477             }
9478           goto check_dup_generic;
9479
9480         check_dup_generic:
9481           t = OMP_CLAUSE_DECL (c);
9482           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9483             {
9484               error ("%qE is not a variable in clause %qs", t, name);
9485               remove = true;
9486             }
9487           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9488                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
9489                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9490             {
9491               error ("%qE appears more than once in data clauses", t);
9492               remove = true;
9493             }
9494           else
9495             bitmap_set_bit (&generic_head, DECL_UID (t));
9496           break;
9497
9498         case OMP_CLAUSE_FIRSTPRIVATE:
9499           name = "firstprivate";
9500           t = OMP_CLAUSE_DECL (c);
9501           need_complete = true;
9502           need_implicitly_determined = true;
9503           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9504             {
9505               error ("%qE is not a variable in clause %<firstprivate%>", t);
9506               remove = true;
9507             }
9508           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9509                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
9510             {
9511               error ("%qE appears more than once in data clauses", t);
9512               remove = true;
9513             }
9514           else
9515             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
9516           break;
9517
9518         case OMP_CLAUSE_LASTPRIVATE:
9519           name = "lastprivate";
9520           t = OMP_CLAUSE_DECL (c);
9521           need_complete = true;
9522           need_implicitly_determined = true;
9523           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9524             {
9525               error ("%qE is not a variable in clause %<lastprivate%>", t);
9526               remove = true;
9527             }
9528           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9529                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9530             {
9531               error ("%qE appears more than once in data clauses", t);
9532               remove = true;
9533             }
9534           else
9535             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
9536           break;
9537
9538         case OMP_CLAUSE_IF:
9539         case OMP_CLAUSE_NUM_THREADS:
9540         case OMP_CLAUSE_SCHEDULE:
9541         case OMP_CLAUSE_NOWAIT:
9542         case OMP_CLAUSE_ORDERED:
9543         case OMP_CLAUSE_DEFAULT:
9544         case OMP_CLAUSE_UNTIED:
9545         case OMP_CLAUSE_COLLAPSE:
9546           pc = &OMP_CLAUSE_CHAIN (c);
9547           continue;
9548
9549         default:
9550           gcc_unreachable ();
9551         }
9552
9553       if (!remove)
9554         {
9555           t = OMP_CLAUSE_DECL (c);
9556
9557           if (need_complete)
9558             {
9559               t = require_complete_type (t);
9560               if (t == error_mark_node)
9561                 remove = true;
9562             }
9563
9564           if (need_implicitly_determined)
9565             {
9566               const char *share_name = NULL;
9567
9568               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
9569                 share_name = "threadprivate";
9570               else switch (c_omp_predetermined_sharing (t))
9571                 {
9572                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
9573                   break;
9574                 case OMP_CLAUSE_DEFAULT_SHARED:
9575                   share_name = "shared";
9576                   break;
9577                 case OMP_CLAUSE_DEFAULT_PRIVATE:
9578                   share_name = "private";
9579                   break;
9580                 default:
9581                   gcc_unreachable ();
9582                 }
9583               if (share_name)
9584                 {
9585                   error ("%qE is predetermined %qs for %qs",
9586                          t, share_name, name);
9587                   remove = true;
9588                 }
9589             }
9590         }
9591
9592       if (remove)
9593         *pc = OMP_CLAUSE_CHAIN (c);
9594       else
9595         pc = &OMP_CLAUSE_CHAIN (c);
9596     }
9597
9598   bitmap_obstack_release (NULL);
9599   return clauses;
9600 }
9601
9602 /* Make a variant type in the proper way for C/C++, propagating qualifiers
9603    down to the element type of an array.  */
9604
9605 tree
9606 c_build_qualified_type (tree type, int type_quals)
9607 {
9608   if (type == error_mark_node)
9609     return type;
9610
9611   if (TREE_CODE (type) == ARRAY_TYPE)
9612     {
9613       tree t;
9614       tree element_type = c_build_qualified_type (TREE_TYPE (type),
9615                                                   type_quals);
9616
9617       /* See if we already have an identically qualified type.  */
9618       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
9619         {
9620           if (TYPE_QUALS (strip_array_types (t)) == type_quals
9621               && TYPE_NAME (t) == TYPE_NAME (type)
9622               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
9623               && attribute_list_equal (TYPE_ATTRIBUTES (t),
9624                                        TYPE_ATTRIBUTES (type)))
9625             break;
9626         }
9627       if (!t)
9628         {
9629           tree domain = TYPE_DOMAIN (type);
9630
9631           t = build_variant_type_copy (type);
9632           TREE_TYPE (t) = element_type;
9633
9634           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
9635               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
9636             SET_TYPE_STRUCTURAL_EQUALITY (t);
9637           else if (TYPE_CANONICAL (element_type) != element_type
9638                    || (domain && TYPE_CANONICAL (domain) != domain))
9639             {
9640               tree unqualified_canon
9641                 = build_array_type (TYPE_CANONICAL (element_type),
9642                                     domain? TYPE_CANONICAL (domain)
9643                                           : NULL_TREE);
9644               TYPE_CANONICAL (t)
9645                 = c_build_qualified_type (unqualified_canon, type_quals);
9646             }
9647           else
9648             TYPE_CANONICAL (t) = t;
9649         }
9650       return t;
9651     }
9652
9653   /* A restrict-qualified pointer type must be a pointer to object or
9654      incomplete type.  Note that the use of POINTER_TYPE_P also allows
9655      REFERENCE_TYPEs, which is appropriate for C++.  */
9656   if ((type_quals & TYPE_QUAL_RESTRICT)
9657       && (!POINTER_TYPE_P (type)
9658           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
9659     {
9660       error ("invalid use of %<restrict%>");
9661       type_quals &= ~TYPE_QUAL_RESTRICT;
9662     }
9663
9664   return build_qualified_type (type, type_quals);
9665 }