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 (tree, VEC(tree,gc) *, VEC(tree,gc) *, tree,
  91                               tree);
  92 static tree pointer_diff (tree, tree);
  93 static tree convert_for_assignment (tree, tree, tree, enum impl_conv, bool,
  94                                     tree, tree, int);
  95 static tree valid_compound_expr_initializer (tree, tree);
  96 static void push_string (const char *);
  97 static void push_member_name (tree);
  98 static int spelling_length (void);
  99 static char *print_spelling (char *);
 100 static void warning_init (int, const char *);
 101 static tree digest_init (tree, tree, tree, bool, bool, int);
 102 static void output_init_element (tree, tree, bool, tree, tree, int, bool);
 103 static void output_pending_init_elements (int);
 104 static int set_designator (int);
 105 static void push_range_stack (tree);
 106 static void add_pending_init (tree, tree, tree, bool);
 107 static void set_nonincremental_init (void);
 108 static void set_nonincremental_init_from_string (tree);
 109 static tree find_init_member (tree);
 110 static void readonly_error (tree, enum lvalue_use);
 111 static void readonly_warning (tree, enum lvalue_use);
 112 static int lvalue_or_else (const_tree, enum lvalue_use);
 113 static void record_maybe_used_decl (tree);
 114 static int comptypes_internal (const_tree, const_tree);
 115 \f
 116 /* Return true if EXP is a null pointer constant, false otherwise.  */
 117
 118 static bool
 119 null_pointer_constant_p (const_tree expr)
 120 {
 121   /* This should really operate on c_expr structures, but they aren't
 122      yet available everywhere required.  */
 123   tree type = TREE_TYPE (expr);
 124   return (TREE_CODE (expr) == INTEGER_CST
 125           && !TREE_OVERFLOW (expr)
 126           && integer_zerop (expr)
 127           && (INTEGRAL_TYPE_P (type)
 128               || (TREE_CODE (type) == POINTER_TYPE
 129                   && VOID_TYPE_P (TREE_TYPE (type))
 130                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 131 }
 132
 133 /* EXPR may appear in an unevaluated part of an integer constant
 134    expression, but not in an evaluated part.  Wrap it in a
 135    C_MAYBE_CONST_EXPR, or mark it with TREE_OVERFLOW if it is just an
 136    INTEGER_CST and we cannot create a C_MAYBE_CONST_EXPR.  */
 137
 138 static tree
 139 note_integer_operands (tree expr)
 140 {
 141   tree ret;
 142   if (TREE_CODE (expr) == INTEGER_CST && in_late_binary_op)
 143     {
 144       ret = copy_node (expr);
 145       TREE_OVERFLOW (ret) = 1;
 146     }
 147   else
 148     {
 149       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (expr), NULL_TREE, expr);
 150       C_MAYBE_CONST_EXPR_INT_OPERANDS (ret) = 1;
 151     }
 152   return ret;
 153 }
 154
 155 /* Having checked whether EXPR may appear in an unevaluated part of an
 156    integer constant expression and found that it may, remove any
 157    C_MAYBE_CONST_EXPR noting this fact and return the resulting
 158    expression.  */
 159
 160 static inline tree
 161 remove_c_maybe_const_expr (tree expr)
 162 {
 163   if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR)
 164     return C_MAYBE_CONST_EXPR_EXPR (expr);
 165   else
 166     return expr;
 167 }
 168
 169 \f/* This is a cache to hold if two types are compatible or not.  */
 170
 171 struct tagged_tu_seen_cache {
 172   const struct tagged_tu_seen_cache * next;
 173   const_tree t1;
 174   const_tree t2;
 175   /* The return value of tagged_types_tu_compatible_p if we had seen
 176      these two types already.  */
 177   int val;
 178 };
 179
 180 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 181 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 182
 183 /* Do `exp = require_complete_type (exp);' to make sure exp
 184    does not have an incomplete type.  (That includes void types.)  */
 185
 186 tree
 187 require_complete_type (tree value)
 188 {
 189   tree type = TREE_TYPE (value);
 190
 191   if (value == error_mark_node || type == error_mark_node)
 192     return error_mark_node;
 193
 194   /* First, detect a valid value with a complete type.  */
 195   if (COMPLETE_TYPE_P (type))
 196     return value;
 197
 198   c_incomplete_type_error (value, type);
 199   return error_mark_node;
 200 }
 201
 202 /* Print an error message for invalid use of an incomplete type.
 203    VALUE is the expression that was used (or 0 if that isn't known)
 204    and TYPE is the type that was invalid.  */
 205
 206 void
 207 c_incomplete_type_error (const_tree value, const_tree type)
 208 {
 209   const char *type_code_string;
 210
 211   /* Avoid duplicate error message.  */
 212   if (TREE_CODE (type) == ERROR_MARK)
 213     return;
 214
 215   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 216                      || TREE_CODE (value) == PARM_DECL))
 217     error ("%qD has an incomplete type", value);
 218   else
 219     {
 220     retry:
 221       /* We must print an error message.  Be clever about what it says.  */
 222
 223       switch (TREE_CODE (type))
 224         {
 225         case RECORD_TYPE:
 226           type_code_string = "struct";
 227           break;
 228
 229         case UNION_TYPE:
 230           type_code_string = "union";
 231           break;
 232
 233         case ENUMERAL_TYPE:
 234           type_code_string = "enum";
 235           break;
 236
 237         case VOID_TYPE:
 238           error ("invalid use of void expression");
 239           return;
 240
 241         case ARRAY_TYPE:
 242           if (TYPE_DOMAIN (type))
 243             {
 244               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 245                 {
 246                   error ("invalid use of flexible array member");
 247                   return;
 248                 }
 249               type = TREE_TYPE (type);
 250               goto retry;
 251             }
 252           error ("invalid use of array with unspecified bounds");
 253           return;
 254
 255         default:
 256           gcc_unreachable ();
 257         }
 258
 259       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 260         error ("invalid use of undefined type %<%s %E%>",
 261                type_code_string, TYPE_NAME (type));
 262       else
 263         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 264         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 265     }
 266 }
 267
 268 /* Given a type, apply default promotions wrt unnamed function
 269    arguments and return the new type.  */
 270
 271 tree
 272 c_type_promotes_to (tree type)
 273 {
 274   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 275     return double_type_node;
 276
 277   if (c_promoting_integer_type_p (type))
 278     {
 279       /* Preserve unsignedness if not really getting any wider.  */
 280       if (TYPE_UNSIGNED (type)
 281           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 282         return unsigned_type_node;
 283       return integer_type_node;
 284     }
 285
 286   return type;
 287 }
 288
 289 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 290    as well as those of TYPE.  */
 291
 292 static tree
 293 qualify_type (tree type, tree like)
 294 {
 295   return c_build_qualified_type (type,
 296                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 297 }
 298
 299 /* Return true iff the given tree T is a variable length array.  */
 300
 301 bool
 302 c_vla_type_p (const_tree t)
 303 {
 304   if (TREE_CODE (t) == ARRAY_TYPE
 305       && C_TYPE_VARIABLE_SIZE (t))
 306     return true;
 307   return false;
 308 }
 309 \f
 310 /* Return the composite type of two compatible types.
 311
 312    We assume that comptypes has already been done and returned
 313    nonzero; if that isn't so, this may crash.  In particular, we
 314    assume that qualifiers match.  */
 315
 316 tree
 317 composite_type (tree t1, tree t2)
 318 {
 319   enum tree_code code1;
 320   enum tree_code code2;
 321   tree attributes;
 322
 323   /* Save time if the two types are the same.  */
 324
 325   if (t1 == t2) return t1;
 326
 327   /* If one type is nonsense, use the other.  */
 328   if (t1 == error_mark_node)
 329     return t2;
 330   if (t2 == error_mark_node)
 331     return t1;
 332
 333   code1 = TREE_CODE (t1);
 334   code2 = TREE_CODE (t2);
 335
 336   /* Merge the attributes.  */
 337   attributes = targetm.merge_type_attributes (t1, t2);
 338
 339   /* If one is an enumerated type and the other is the compatible
 340      integer type, the composite type might be either of the two
 341      (DR#013 question 3).  For consistency, use the enumerated type as
 342      the composite type.  */
 343
 344   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 345     return t1;
 346   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 347     return t2;
 348
 349   gcc_assert (code1 == code2);
 350
 351   switch (code1)
 352     {
 353     case POINTER_TYPE:
 354       /* For two pointers, do this recursively on the target type.  */
 355       {
 356         tree pointed_to_1 = TREE_TYPE (t1);
 357         tree pointed_to_2 = TREE_TYPE (t2);
 358         tree target = composite_type (pointed_to_1, pointed_to_2);
 359         t1 = build_pointer_type (target);
 360         t1 = build_type_attribute_variant (t1, attributes);
 361         return qualify_type (t1, t2);
 362       }
 363
 364     case ARRAY_TYPE:
 365       {
 366         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 367         int quals;
 368         tree unqual_elt;
 369         tree d1 = TYPE_DOMAIN (t1);
 370         tree d2 = TYPE_DOMAIN (t2);
 371         bool d1_variable, d2_variable;
 372         bool d1_zero, d2_zero;
 373         bool t1_complete, t2_complete;
 374
 375         /* We should not have any type quals on arrays at all.  */
 376         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 377
 378         t1_complete = COMPLETE_TYPE_P (t1);
 379         t2_complete = COMPLETE_TYPE_P (t2);
 380
 381         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 382         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 383
 384         d1_variable = (!d1_zero
 385                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 386                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 387         d2_variable = (!d2_zero
 388                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 389                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 390         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 391         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 392
 393         /* Save space: see if the result is identical to one of the args.  */
 394         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 395             && (d2_variable || d2_zero || !d1_variable))
 396           return build_type_attribute_variant (t1, attributes);
 397         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 398             && (d1_variable || d1_zero || !d2_variable))
 399           return build_type_attribute_variant (t2, attributes);
 400
 401         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 402           return build_type_attribute_variant (t1, attributes);
 403         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 404           return build_type_attribute_variant (t2, attributes);
 405
 406         /* Merge the element types, and have a size if either arg has
 407            one.  We may have qualifiers on the element types.  To set
 408            up TYPE_MAIN_VARIANT correctly, we need to form the
 409            composite of the unqualified types and add the qualifiers
 410            back at the end.  */
 411         quals = TYPE_QUALS (strip_array_types (elt));
 412         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 413         t1 = build_array_type (unqual_elt,
 414                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 415                                              && (d2_variable
 416                                                  || d2_zero
 417                                                  || !d1_variable))
 418                                             ? t1
 419                                             : t2));
 420         /* Ensure a composite type involving a zero-length array type
 421            is a zero-length type not an incomplete type.  */
 422         if (d1_zero && d2_zero
 423             && (t1_complete || t2_complete)
 424             && !COMPLETE_TYPE_P (t1))
 425           {
 426             TYPE_SIZE (t1) = bitsize_zero_node;
 427             TYPE_SIZE_UNIT (t1) = size_zero_node;
 428           }
 429         t1 = c_build_qualified_type (t1, quals);
 430         return build_type_attribute_variant (t1, attributes);
 431       }
 432
 433     case ENUMERAL_TYPE:
 434     case RECORD_TYPE:
 435     case UNION_TYPE:
 436       if (attributes != NULL)
 437         {
 438           /* Try harder not to create a new aggregate type.  */
 439           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 440             return t1;
 441           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 442             return t2;
 443         }
 444       return build_type_attribute_variant (t1, attributes);
 445
 446     case FUNCTION_TYPE:
 447       /* Function types: prefer the one that specified arg types.
 448          If both do, merge the arg types.  Also merge the return types.  */
 449       {
 450         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 451         tree p1 = TYPE_ARG_TYPES (t1);
 452         tree p2 = TYPE_ARG_TYPES (t2);
 453         int len;
 454         tree newargs, n;
 455         int i;
 456
 457         /* Save space: see if the result is identical to one of the args.  */
 458         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 459           return build_type_attribute_variant (t1, attributes);
 460         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 461           return build_type_attribute_variant (t2, attributes);
 462
 463         /* Simple way if one arg fails to specify argument types.  */
 464         if (TYPE_ARG_TYPES (t1) == 0)
 465          {
 466             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 467             t1 = build_type_attribute_variant (t1, attributes);
 468             return qualify_type (t1, t2);
 469          }
 470         if (TYPE_ARG_TYPES (t2) == 0)
 471          {
 472            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 473            t1 = build_type_attribute_variant (t1, attributes);
 474            return qualify_type (t1, t2);
 475          }
 476
 477         /* If both args specify argument types, we must merge the two
 478            lists, argument by argument.  */
 479         /* Tell global_bindings_p to return false so that variable_size
 480            doesn't die on VLAs in parameter types.  */
 481         c_override_global_bindings_to_false = true;
 482
 483         len = list_length (p1);
 484         newargs = 0;
 485
 486         for (i = 0; i < len; i++)
 487           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 488
 489         n = newargs;
 490
 491         for (; p1;
 492              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 493           {
 494             /* A null type means arg type is not specified.
 495                Take whatever the other function type has.  */
 496             if (TREE_VALUE (p1) == 0)
 497               {
 498                 TREE_VALUE (n) = TREE_VALUE (p2);
 499                 goto parm_done;
 500               }
 501             if (TREE_VALUE (p2) == 0)
 502               {
 503                 TREE_VALUE (n) = TREE_VALUE (p1);
 504                 goto parm_done;
 505               }
 506
 507             /* Given  wait (union {union wait *u; int *i} *)
 508                and  wait (union wait *),
 509                prefer  union wait *  as type of parm.  */
 510             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 511                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 512               {
 513                 tree memb;
 514                 tree mv2 = TREE_VALUE (p2);
 515                 if (mv2 && mv2 != error_mark_node
 516                     && TREE_CODE (mv2) != ARRAY_TYPE)
 517                   mv2 = TYPE_MAIN_VARIANT (mv2);
 518                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 519                      memb; memb = TREE_CHAIN (memb))
 520                   {
 521                     tree mv3 = TREE_TYPE (memb);
 522                     if (mv3 && mv3 != error_mark_node
 523                         && TREE_CODE (mv3) != ARRAY_TYPE)
 524                       mv3 = TYPE_MAIN_VARIANT (mv3);
 525                     if (comptypes (mv3, mv2))
 526                       {
 527                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 528                                                          TREE_VALUE (p2));
 529                         pedwarn (input_location, OPT_pedantic,
 530                                  "function types not truly compatible in ISO C");
 531                         goto parm_done;
 532                       }
 533                   }
 534               }
 535             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 536                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 537               {
 538                 tree memb;
 539                 tree mv1 = TREE_VALUE (p1);
 540                 if (mv1 && mv1 != error_mark_node
 541                     && TREE_CODE (mv1) != ARRAY_TYPE)
 542                   mv1 = TYPE_MAIN_VARIANT (mv1);
 543                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 544                      memb; memb = TREE_CHAIN (memb))
 545                   {
 546                     tree mv3 = TREE_TYPE (memb);
 547                     if (mv3 && mv3 != error_mark_node
 548                         && TREE_CODE (mv3) != ARRAY_TYPE)
 549                       mv3 = TYPE_MAIN_VARIANT (mv3);
 550                     if (comptypes (mv3, mv1))
 551                       {
 552                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 553                                                          TREE_VALUE (p1));
 554                         pedwarn (input_location, OPT_pedantic,
 555                                  "function types not truly compatible in ISO C");
 556                         goto parm_done;
 557                       }
 558                   }
 559               }
 560             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 561           parm_done: ;
 562           }
 563
 564         c_override_global_bindings_to_false = false;
 565         t1 = build_function_type (valtype, newargs);
 566         t1 = qualify_type (t1, t2);
 567         /* ... falls through ...  */
 568       }
 569
 570     default:
 571       return build_type_attribute_variant (t1, attributes);
 572     }
 573
 574 }
 575
 576 /* Return the type of a conditional expression between pointers to
 577    possibly differently qualified versions of compatible types.
 578
 579    We assume that comp_target_types has already been done and returned
 580    nonzero; if that isn't so, this may crash.  */
 581
 582 static tree
 583 common_pointer_type (tree t1, tree t2)
 584 {
 585   tree attributes;
 586   tree pointed_to_1, mv1;
 587   tree pointed_to_2, mv2;
 588   tree target;
 589   unsigned target_quals;
 590
 591   /* Save time if the two types are the same.  */
 592
 593   if (t1 == t2) return t1;
 594
 595   /* If one type is nonsense, use the other.  */
 596   if (t1 == error_mark_node)
 597     return t2;
 598   if (t2 == error_mark_node)
 599     return t1;
 600
 601   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 602               && TREE_CODE (t2) == POINTER_TYPE);
 603
 604   /* Merge the attributes.  */
 605   attributes = targetm.merge_type_attributes (t1, t2);
 606
 607   /* Find the composite type of the target types, and combine the
 608      qualifiers of the two types' targets.  Do not lose qualifiers on
 609      array element types by taking the TYPE_MAIN_VARIANT.  */
 610   mv1 = pointed_to_1 = TREE_TYPE (t1);
 611   mv2 = pointed_to_2 = TREE_TYPE (t2);
 612   if (TREE_CODE (mv1) != ARRAY_TYPE)
 613     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 614   if (TREE_CODE (mv2) != ARRAY_TYPE)
 615     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 616   target = composite_type (mv1, mv2);
 617
 618   /* For function types do not merge const qualifiers, but drop them
 619      if used inconsistently.  The middle-end uses these to mark const
 620      and noreturn functions.  */
 621   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 622     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 623   else
 624     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 625   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 626   return build_type_attribute_variant (t1, attributes);
 627 }
 628
 629 /* Return the common type for two arithmetic types under the usual
 630    arithmetic conversions.  The default conversions have already been
 631    applied, and enumerated types converted to their compatible integer
 632    types.  The resulting type is unqualified and has no attributes.
 633
 634    This is the type for the result of most arithmetic operations
 635    if the operands have the given two types.  */
 636
 637 static tree
 638 c_common_type (tree t1, tree t2)
 639 {
 640   enum tree_code code1;
 641   enum tree_code code2;
 642
 643   /* If one type is nonsense, use the other.  */
 644   if (t1 == error_mark_node)
 645     return t2;
 646   if (t2 == error_mark_node)
 647     return t1;
 648
 649   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 650     t1 = TYPE_MAIN_VARIANT (t1);
 651
 652   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 653     t2 = TYPE_MAIN_VARIANT (t2);
 654
 655   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 656     t1 = build_type_attribute_variant (t1, NULL_TREE);
 657
 658   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 659     t2 = build_type_attribute_variant (t2, NULL_TREE);
 660
 661   /* Save time if the two types are the same.  */
 662
 663   if (t1 == t2) return t1;
 664
 665   code1 = TREE_CODE (t1);
 666   code2 = TREE_CODE (t2);
 667
 668   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 669               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 670               || code1 == INTEGER_TYPE);
 671   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 672               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 673               || code2 == INTEGER_TYPE);
 674
 675   /* When one operand is a decimal float type, the other operand cannot be
 676      a generic float type or a complex type.  We also disallow vector types
 677      here.  */
 678   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 679       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 680     {
 681       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 682         {
 683           error ("can%'t mix operands of decimal float and vector types");
 684           return error_mark_node;
 685         }
 686       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 687         {
 688           error ("can%'t mix operands of decimal float and complex types");
 689           return error_mark_node;
 690         }
 691       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 692         {
 693           error ("can%'t mix operands of decimal float and other float types");
 694           return error_mark_node;
 695         }
 696     }
 697
 698   /* If one type is a vector type, return that type.  (How the usual
 699      arithmetic conversions apply to the vector types extension is not
 700      precisely specified.)  */
 701   if (code1 == VECTOR_TYPE)
 702     return t1;
 703
 704   if (code2 == VECTOR_TYPE)
 705     return t2;
 706
 707   /* If one type is complex, form the common type of the non-complex
 708      components, then make that complex.  Use T1 or T2 if it is the
 709      required type.  */
 710   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 711     {
 712       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 713       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 714       tree subtype = c_common_type (subtype1, subtype2);
 715
 716       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 717         return t1;
 718       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 719         return t2;
 720       else
 721         return build_complex_type (subtype);
 722     }
 723
 724   /* If only one is real, use it as the result.  */
 725
 726   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 727     return t1;
 728
 729   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 730     return t2;
 731
 732   /* If both are real and either are decimal floating point types, use
 733      the decimal floating point type with the greater precision. */
 734
 735   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 736     {
 737       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 738           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 739         return dfloat128_type_node;
 740       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 741                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 742         return dfloat64_type_node;
 743       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 744                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 745         return dfloat32_type_node;
 746     }
 747
 748   /* Deal with fixed-point types.  */
 749   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 750     {
 751       unsigned int unsignedp = 0, satp = 0;
 752       enum machine_mode m1, m2;
 753       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 754
 755       m1 = TYPE_MODE (t1);
 756       m2 = TYPE_MODE (t2);
 757
 758       /* If one input type is saturating, the result type is saturating.  */
 759       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 760         satp = 1;
 761
 762       /* If both fixed-point types are unsigned, the result type is unsigned.
 763          When mixing fixed-point and integer types, follow the sign of the
 764          fixed-point type.
 765          Otherwise, the result type is signed.  */
 766       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 767            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 768           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 769               && TYPE_UNSIGNED (t1))
 770           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 771               && TYPE_UNSIGNED (t2)))
 772         unsignedp = 1;
 773
 774       /* The result type is signed.  */
 775       if (unsignedp == 0)
 776         {
 777           /* If the input type is unsigned, we need to convert to the
 778              signed type.  */
 779           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 780             {
 781               enum mode_class mclass = (enum mode_class) 0;
 782               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 783                 mclass = MODE_FRACT;
 784               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 785                 mclass = MODE_ACCUM;
 786               else
 787                 gcc_unreachable ();
 788               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 789             }
 790           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 791             {
 792               enum mode_class mclass = (enum mode_class) 0;
 793               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 794                 mclass = MODE_FRACT;
 795               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 796                 mclass = MODE_ACCUM;
 797               else
 798                 gcc_unreachable ();
 799               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 800             }
 801         }
 802
 803       if (code1 == FIXED_POINT_TYPE)
 804         {
 805           fbit1 = GET_MODE_FBIT (m1);
 806           ibit1 = GET_MODE_IBIT (m1);
 807         }
 808       else
 809         {
 810           fbit1 = 0;
 811           /* Signed integers need to subtract one sign bit.  */
 812           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 813         }
 814
 815       if (code2 == FIXED_POINT_TYPE)
 816         {
 817           fbit2 = GET_MODE_FBIT (m2);
 818           ibit2 = GET_MODE_IBIT (m2);
 819         }
 820       else
 821         {
 822           fbit2 = 0;
 823           /* Signed integers need to subtract one sign bit.  */
 824           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 825         }
 826
 827       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 828       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 829       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 830                                                  satp);
 831     }
 832
 833   /* Both real or both integers; use the one with greater precision.  */
 834
 835   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 836     return t1;
 837   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 838     return t2;
 839
 840   /* Same precision.  Prefer long longs to longs to ints when the
 841      same precision, following the C99 rules on integer type rank
 842      (which are equivalent to the C90 rules for C90 types).  */
 843
 844   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 845       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 846     return long_long_unsigned_type_node;
 847
 848   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 849       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 850     {
 851       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 852         return long_long_unsigned_type_node;
 853       else
 854         return long_long_integer_type_node;
 855     }
 856
 857   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 858       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 859     return long_unsigned_type_node;
 860
 861   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 862       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 863     {
 864       /* But preserve unsignedness from the other type,
 865          since long cannot hold all the values of an unsigned int.  */
 866       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 867         return long_unsigned_type_node;
 868       else
 869         return long_integer_type_node;
 870     }
 871
 872   /* Likewise, prefer long double to double even if same size.  */
 873   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 874       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 875     return long_double_type_node;
 876
 877   /* Otherwise prefer the unsigned one.  */
 878
 879   if (TYPE_UNSIGNED (t1))
 880     return t1;
 881   else
 882     return t2;
 883 }
 884 \f
 885 /* Wrapper around c_common_type that is used by c-common.c and other
 886    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 887    are allowed here and are converted to their compatible integer types.
 888    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 889    preferably a non-Boolean type as the common type.  */
 890 tree
 891 common_type (tree t1, tree t2)
 892 {
 893   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 894     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 895   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 896     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 897
 898   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 899   if (TREE_CODE (t1) == BOOLEAN_TYPE
 900       && TREE_CODE (t2) == BOOLEAN_TYPE)
 901     return boolean_type_node;
 902
 903   /* If either type is BOOLEAN_TYPE, then return the other.  */
 904   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 905     return t2;
 906   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 907     return t1;
 908
 909   return c_common_type (t1, t2);
 910 }
 911
 912 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 913    or various other operations.  Return 2 if they are compatible
 914    but a warning may be needed if you use them together.  */
 915
 916 int
 917 comptypes (tree type1, tree type2)
 918 {
 919   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 920   int val;
 921
 922   val = comptypes_internal (type1, type2);
 923   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 924
 925   return val;
 926 }
 927 \f
 928 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 929    or various other operations.  Return 2 if they are compatible
 930    but a warning may be needed if you use them together.  This
 931    differs from comptypes, in that we don't free the seen types.  */
 932
 933 static int
 934 comptypes_internal (const_tree type1, const_tree type2)
 935 {
 936   const_tree t1 = type1;
 937   const_tree t2 = type2;
 938   int attrval, val;
 939
 940   /* Suppress errors caused by previously reported errors.  */
 941
 942   if (t1 == t2 || !t1 || !t2
 943       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 944     return 1;
 945
 946   /* If either type is the internal version of sizetype, return the
 947      language version.  */
 948   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 949       && TYPE_ORIG_SIZE_TYPE (t1))
 950     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 951
 952   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 953       && TYPE_ORIG_SIZE_TYPE (t2))
 954     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 955
 956
 957   /* Enumerated types are compatible with integer types, but this is
 958      not transitive: two enumerated types in the same translation unit
 959      are compatible with each other only if they are the same type.  */
 960
 961   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 962     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 963   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 964     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 965
 966   if (t1 == t2)
 967     return 1;
 968
 969   /* Different classes of types can't be compatible.  */
 970
 971   if (TREE_CODE (t1) != TREE_CODE (t2))
 972     return 0;
 973
 974   /* Qualifiers must match. C99 6.7.3p9 */
 975
 976   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 977     return 0;
 978
 979   /* Allow for two different type nodes which have essentially the same
 980      definition.  Note that we already checked for equality of the type
 981      qualifiers (just above).  */
 982
 983   if (TREE_CODE (t1) != ARRAY_TYPE
 984       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 985     return 1;
 986
 987   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 988   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 989      return 0;
 990
 991   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 992   val = 0;
 993
 994   switch (TREE_CODE (t1))
 995     {
 996     case POINTER_TYPE:
 997       /* Do not remove mode or aliasing information.  */
 998       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 999           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
1000         break;
1001       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
1002              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
1003       break;
1004
1005     case FUNCTION_TYPE:
1006       val = function_types_compatible_p (t1, t2);
1007       break;
1008
1009     case ARRAY_TYPE:
1010       {
1011         tree d1 = TYPE_DOMAIN (t1);
1012         tree d2 = TYPE_DOMAIN (t2);
1013         bool d1_variable, d2_variable;
1014         bool d1_zero, d2_zero;
1015         val = 1;
1016
1017         /* Target types must match incl. qualifiers.  */
1018         if (TREE_TYPE (t1) != TREE_TYPE (t2)
1019             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
1020           return 0;
1021
1022         /* Sizes must match unless one is missing or variable.  */
1023         if (d1 == 0 || d2 == 0 || d1 == d2)
1024           break;
1025
1026         d1_zero = !TYPE_MAX_VALUE (d1);
1027         d2_zero = !TYPE_MAX_VALUE (d2);
1028
1029         d1_variable = (!d1_zero
1030                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
1031                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
1032         d2_variable = (!d2_zero
1033                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
1034                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
1035         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
1036         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
1037
1038         if (d1_variable || d2_variable)
1039           break;
1040         if (d1_zero && d2_zero)
1041           break;
1042         if (d1_zero || d2_zero
1043             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
1044             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
1045           val = 0;
1046
1047         break;
1048       }
1049
1050     case ENUMERAL_TYPE:
1051     case RECORD_TYPE:
1052     case UNION_TYPE:
1053       if (val != 1 && !same_translation_unit_p (t1, t2))
1054         {
1055           tree a1 = TYPE_ATTRIBUTES (t1);
1056           tree a2 = TYPE_ATTRIBUTES (t2);
1057
1058           if (! attribute_list_contained (a1, a2)
1059               && ! attribute_list_contained (a2, a1))
1060             break;
1061
1062           if (attrval != 2)
1063             return tagged_types_tu_compatible_p (t1, t2);
1064           val = tagged_types_tu_compatible_p (t1, t2);
1065         }
1066       break;
1067
1068     case VECTOR_TYPE:
1069       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1070             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1071       break;
1072
1073     default:
1074       break;
1075     }
1076   return attrval == 2 && val == 1 ? 2 : val;
1077 }
1078
1079 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1080    ignoring their qualifiers.  */
1081
1082 static int
1083 comp_target_types (tree ttl, tree ttr)
1084 {
1085   int val;
1086   tree mvl, mvr;
1087
1088   /* Do not lose qualifiers on element types of array types that are
1089      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1090   mvl = TREE_TYPE (ttl);
1091   mvr = TREE_TYPE (ttr);
1092   if (TREE_CODE (mvl) != ARRAY_TYPE)
1093     mvl = TYPE_MAIN_VARIANT (mvl);
1094   if (TREE_CODE (mvr) != ARRAY_TYPE)
1095     mvr = TYPE_MAIN_VARIANT (mvr);
1096   val = comptypes (mvl, mvr);
1097
1098   if (val == 2)
1099     pedwarn (input_location, OPT_pedantic, "types are not quite compatible");
1100   return val;
1101 }
1102 \f
1103 /* Subroutines of `comptypes'.  */
1104
1105 /* Determine whether two trees derive from the same translation unit.
1106    If the CONTEXT chain ends in a null, that tree's context is still
1107    being parsed, so if two trees have context chains ending in null,
1108    they're in the same translation unit.  */
1109 int
1110 same_translation_unit_p (const_tree t1, const_tree t2)
1111 {
1112   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1113     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1114       {
1115       case tcc_declaration:
1116         t1 = DECL_CONTEXT (t1); break;
1117       case tcc_type:
1118         t1 = TYPE_CONTEXT (t1); break;
1119       case tcc_exceptional:
1120         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1121       default: gcc_unreachable ();
1122       }
1123
1124   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1125     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1126       {
1127       case tcc_declaration:
1128         t2 = DECL_CONTEXT (t2); break;
1129       case tcc_type:
1130         t2 = TYPE_CONTEXT (t2); break;
1131       case tcc_exceptional:
1132         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1133       default: gcc_unreachable ();
1134       }
1135
1136   return t1 == t2;
1137 }
1138
1139 /* Allocate the seen two types, assuming that they are compatible. */
1140
1141 static struct tagged_tu_seen_cache *
1142 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1143 {
1144   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1145   tu->next = tagged_tu_seen_base;
1146   tu->t1 = t1;
1147   tu->t2 = t2;
1148
1149   tagged_tu_seen_base = tu;
1150
1151   /* The C standard says that two structures in different translation
1152      units are compatible with each other only if the types of their
1153      fields are compatible (among other things).  We assume that they
1154      are compatible until proven otherwise when building the cache.
1155      An example where this can occur is:
1156      struct a
1157      {
1158        struct a *next;
1159      };
1160      If we are comparing this against a similar struct in another TU,
1161      and did not assume they were compatible, we end up with an infinite
1162      loop.  */
1163   tu->val = 1;
1164   return tu;
1165 }
1166
1167 /* Free the seen types until we get to TU_TIL. */
1168
1169 static void
1170 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1171 {
1172   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1173   while (tu != tu_til)
1174     {
1175       const struct tagged_tu_seen_cache *const tu1
1176         = (const struct tagged_tu_seen_cache *) tu;
1177       tu = tu1->next;
1178       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1179     }
1180   tagged_tu_seen_base = tu_til;
1181 }
1182
1183 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1184    compatible.  If the two types are not the same (which has been
1185    checked earlier), this can only happen when multiple translation
1186    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1187    rules.  */
1188
1189 static int
1190 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1191 {
1192   tree s1, s2;
1193   bool needs_warning = false;
1194
1195   /* We have to verify that the tags of the types are the same.  This
1196      is harder than it looks because this may be a typedef, so we have
1197      to go look at the original type.  It may even be a typedef of a
1198      typedef...
1199      In the case of compiler-created builtin structs the TYPE_DECL
1200      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1201   while (TYPE_NAME (t1)
1202          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1203          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1204     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1205
1206   while (TYPE_NAME (t2)
1207          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1208          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1209     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1210
1211   /* C90 didn't have the requirement that the two tags be the same.  */
1212   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1213     return 0;
1214
1215   /* C90 didn't say what happened if one or both of the types were
1216      incomplete; we choose to follow C99 rules here, which is that they
1217      are compatible.  */
1218   if (TYPE_SIZE (t1) == NULL
1219       || TYPE_SIZE (t2) == NULL)
1220     return 1;
1221
1222   {
1223     const struct tagged_tu_seen_cache * tts_i;
1224     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1225       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1226         return tts_i->val;
1227   }
1228
1229   switch (TREE_CODE (t1))
1230     {
1231     case ENUMERAL_TYPE:
1232       {
1233         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1234         /* Speed up the case where the type values are in the same order.  */
1235         tree tv1 = TYPE_VALUES (t1);
1236         tree tv2 = TYPE_VALUES (t2);
1237
1238         if (tv1 == tv2)
1239           {
1240             return 1;
1241           }
1242
1243         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1244           {
1245             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1246               break;
1247             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1248               {
1249                 tu->val = 0;
1250                 return 0;
1251               }
1252           }
1253
1254         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1255           {
1256             return 1;
1257           }
1258         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1259           {
1260             tu->val = 0;
1261             return 0;
1262           }
1263
1264         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1265           {
1266             tu->val = 0;
1267             return 0;
1268           }
1269
1270         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1271           {
1272             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1273             if (s2 == NULL
1274                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1275               {
1276                 tu->val = 0;
1277                 return 0;
1278               }
1279           }
1280         return 1;
1281       }
1282
1283     case UNION_TYPE:
1284       {
1285         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1286         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1287           {
1288             tu->val = 0;
1289             return 0;
1290           }
1291
1292         /*  Speed up the common case where the fields are in the same order. */
1293         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1294              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1295           {
1296             int result;
1297
1298             if (DECL_NAME (s1) != DECL_NAME (s2))
1299               break;
1300             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1301
1302             if (result != 1 && !DECL_NAME (s1))
1303               break;
1304             if (result == 0)
1305               {
1306                 tu->val = 0;
1307                 return 0;
1308               }
1309             if (result == 2)
1310               needs_warning = true;
1311
1312             if (TREE_CODE (s1) == FIELD_DECL
1313                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1314                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1315               {
1316                 tu->val = 0;
1317                 return 0;
1318               }
1319           }
1320         if (!s1 && !s2)
1321           {
1322             tu->val = needs_warning ? 2 : 1;
1323             return tu->val;
1324           }
1325
1326         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1327           {
1328             bool ok = false;
1329
1330             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1331               if (DECL_NAME (s1) == DECL_NAME (s2))
1332                 {
1333                   int result;
1334
1335                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1336
1337                   if (result != 1 && !DECL_NAME (s1))
1338                     continue;
1339                   if (result == 0)
1340                     {
1341                       tu->val = 0;
1342                       return 0;
1343                     }
1344                   if (result == 2)
1345                     needs_warning = true;
1346
1347                   if (TREE_CODE (s1) == FIELD_DECL
1348                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1349                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1350                     break;
1351
1352                   ok = true;
1353                   break;
1354                 }
1355             if (!ok)
1356               {
1357                 tu->val = 0;
1358                 return 0;
1359               }
1360           }
1361         tu->val = needs_warning ? 2 : 10;
1362         return tu->val;
1363       }
1364
1365     case RECORD_TYPE:
1366       {
1367         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1368
1369         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1370              s1 && s2;
1371              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1372           {
1373             int result;
1374             if (TREE_CODE (s1) != TREE_CODE (s2)
1375                 || DECL_NAME (s1) != DECL_NAME (s2))
1376               break;
1377             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1378             if (result == 0)
1379               break;
1380             if (result == 2)
1381               needs_warning = true;
1382
1383             if (TREE_CODE (s1) == FIELD_DECL
1384                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1385                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1386               break;
1387           }
1388         if (s1 && s2)
1389           tu->val = 0;
1390         else
1391           tu->val = needs_warning ? 2 : 1;
1392         return tu->val;
1393       }
1394
1395     default:
1396       gcc_unreachable ();
1397     }
1398 }
1399
1400 /* Return 1 if two function types F1 and F2 are compatible.
1401    If either type specifies no argument types,
1402    the other must specify a fixed number of self-promoting arg types.
1403    Otherwise, if one type specifies only the number of arguments,
1404    the other must specify that number of self-promoting arg types.
1405    Otherwise, the argument types must match.  */
1406
1407 static int
1408 function_types_compatible_p (const_tree f1, const_tree f2)
1409 {
1410   tree args1, args2;
1411   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1412   int val = 1;
1413   int val1;
1414   tree ret1, ret2;
1415
1416   ret1 = TREE_TYPE (f1);
1417   ret2 = TREE_TYPE (f2);
1418
1419   /* 'volatile' qualifiers on a function's return type used to mean
1420      the function is noreturn.  */
1421   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1422     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1423   if (TYPE_VOLATILE (ret1))
1424     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1425                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1426   if (TYPE_VOLATILE (ret2))
1427     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1428                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1429   val = comptypes_internal (ret1, ret2);
1430   if (val == 0)
1431     return 0;
1432
1433   args1 = TYPE_ARG_TYPES (f1);
1434   args2 = TYPE_ARG_TYPES (f2);
1435
1436   /* An unspecified parmlist matches any specified parmlist
1437      whose argument types don't need default promotions.  */
1438
1439   if (args1 == 0)
1440     {
1441       if (!self_promoting_args_p (args2))
1442         return 0;
1443       /* If one of these types comes from a non-prototype fn definition,
1444          compare that with the other type's arglist.
1445          If they don't match, ask for a warning (but no error).  */
1446       if (TYPE_ACTUAL_ARG_TYPES (f1)
1447           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1448         val = 2;
1449       return val;
1450     }
1451   if (args2 == 0)
1452     {
1453       if (!self_promoting_args_p (args1))
1454         return 0;
1455       if (TYPE_ACTUAL_ARG_TYPES (f2)
1456           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1457         val = 2;
1458       return val;
1459     }
1460
1461   /* Both types have argument lists: compare them and propagate results.  */
1462   val1 = type_lists_compatible_p (args1, args2);
1463   return val1 != 1 ? val1 : val;
1464 }
1465
1466 /* Check two lists of types for compatibility,
1467    returning 0 for incompatible, 1 for compatible,
1468    or 2 for compatible with warning.  */
1469
1470 static int
1471 type_lists_compatible_p (const_tree args1, const_tree args2)
1472 {
1473   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1474   int val = 1;
1475   int newval = 0;
1476
1477   while (1)
1478     {
1479       tree a1, mv1, a2, mv2;
1480       if (args1 == 0 && args2 == 0)
1481         return val;
1482       /* If one list is shorter than the other,
1483          they fail to match.  */
1484       if (args1 == 0 || args2 == 0)
1485         return 0;
1486       mv1 = a1 = TREE_VALUE (args1);
1487       mv2 = a2 = TREE_VALUE (args2);
1488       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1489         mv1 = TYPE_MAIN_VARIANT (mv1);
1490       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1491         mv2 = TYPE_MAIN_VARIANT (mv2);
1492       /* A null pointer instead of a type
1493          means there is supposed to be an argument
1494          but nothing is specified about what type it has.
1495          So match anything that self-promotes.  */
1496       if (a1 == 0)
1497         {
1498           if (c_type_promotes_to (a2) != a2)
1499             return 0;
1500         }
1501       else if (a2 == 0)
1502         {
1503           if (c_type_promotes_to (a1) != a1)
1504             return 0;
1505         }
1506       /* If one of the lists has an error marker, ignore this arg.  */
1507       else if (TREE_CODE (a1) == ERROR_MARK
1508                || TREE_CODE (a2) == ERROR_MARK)
1509         ;
1510       else if (!(newval = comptypes_internal (mv1, mv2)))
1511         {
1512           /* Allow  wait (union {union wait *u; int *i} *)
1513              and  wait (union wait *)  to be compatible.  */
1514           if (TREE_CODE (a1) == UNION_TYPE
1515               && (TYPE_NAME (a1) == 0
1516                   || TYPE_TRANSPARENT_UNION (a1))
1517               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1518               && tree_int_cst_equal (TYPE_SIZE (a1),
1519                                      TYPE_SIZE (a2)))
1520             {
1521               tree memb;
1522               for (memb = TYPE_FIELDS (a1);
1523                    memb; memb = TREE_CHAIN (memb))
1524                 {
1525                   tree mv3 = TREE_TYPE (memb);
1526                   if (mv3 && mv3 != error_mark_node
1527                       && TREE_CODE (mv3) != ARRAY_TYPE)
1528                     mv3 = TYPE_MAIN_VARIANT (mv3);
1529                   if (comptypes_internal (mv3, mv2))
1530                     break;
1531                 }
1532               if (memb == 0)
1533                 return 0;
1534             }
1535           else if (TREE_CODE (a2) == UNION_TYPE
1536                    && (TYPE_NAME (a2) == 0
1537                        || TYPE_TRANSPARENT_UNION (a2))
1538                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1539                    && tree_int_cst_equal (TYPE_SIZE (a2),
1540                                           TYPE_SIZE (a1)))
1541             {
1542               tree memb;
1543               for (memb = TYPE_FIELDS (a2);
1544                    memb; memb = TREE_CHAIN (memb))
1545                 {
1546                   tree mv3 = TREE_TYPE (memb);
1547                   if (mv3 && mv3 != error_mark_node
1548                       && TREE_CODE (mv3) != ARRAY_TYPE)
1549                     mv3 = TYPE_MAIN_VARIANT (mv3);
1550                   if (comptypes_internal (mv3, mv1))
1551                     break;
1552                 }
1553               if (memb == 0)
1554                 return 0;
1555             }
1556           else
1557             return 0;
1558         }
1559
1560       /* comptypes said ok, but record if it said to warn.  */
1561       if (newval > val)
1562         val = newval;
1563
1564       args1 = TREE_CHAIN (args1);
1565       args2 = TREE_CHAIN (args2);
1566     }
1567 }
1568 \f
1569 /* Compute the size to increment a pointer by.  */
1570
1571 static tree
1572 c_size_in_bytes (const_tree type)
1573 {
1574   enum tree_code code = TREE_CODE (type);
1575
1576   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1577     return size_one_node;
1578
1579   if (!COMPLETE_OR_VOID_TYPE_P (type))
1580     {
1581       error ("arithmetic on pointer to an incomplete type");
1582       return size_one_node;
1583     }
1584
1585   /* Convert in case a char is more than one unit.  */
1586   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1587                      size_int (TYPE_PRECISION (char_type_node)
1588                                / BITS_PER_UNIT));
1589 }
1590 \f
1591 /* Return either DECL or its known constant value (if it has one).  */
1592
1593 tree
1594 decl_constant_value (tree decl)
1595 {
1596   if (/* Don't change a variable array bound or initial value to a constant
1597          in a place where a variable is invalid.  Note that DECL_INITIAL
1598          isn't valid for a PARM_DECL.  */
1599       current_function_decl != 0
1600       && TREE_CODE (decl) != PARM_DECL
1601       && !TREE_THIS_VOLATILE (decl)
1602       && TREE_READONLY (decl)
1603       && DECL_INITIAL (decl) != 0
1604       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1605       /* This is invalid if initial value is not constant.
1606          If it has either a function call, a memory reference,
1607          or a variable, then re-evaluating it could give different results.  */
1608       && TREE_CONSTANT (DECL_INITIAL (decl))
1609       /* Check for cases where this is sub-optimal, even though valid.  */
1610       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1611     return DECL_INITIAL (decl);
1612   return decl;
1613 }
1614
1615 /* Convert the array expression EXP to a pointer.  */
1616 static tree
1617 array_to_pointer_conversion (tree exp)
1618 {
1619   tree orig_exp = exp;
1620   tree type = TREE_TYPE (exp);
1621   tree adr;
1622   tree restype = TREE_TYPE (type);
1623   tree ptrtype;
1624
1625   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1626
1627   STRIP_TYPE_NOPS (exp);
1628
1629   if (TREE_NO_WARNING (orig_exp))
1630     TREE_NO_WARNING (exp) = 1;
1631
1632   ptrtype = build_pointer_type (restype);
1633
1634   if (TREE_CODE (exp) == INDIRECT_REF)
1635     return convert (ptrtype, TREE_OPERAND (exp, 0));
1636
1637   adr = build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 1);
1638   return convert (ptrtype, adr);
1639 }
1640
1641 /* Convert the function expression EXP to a pointer.  */
1642 static tree
1643 function_to_pointer_conversion (tree exp)
1644 {
1645   tree orig_exp = exp;
1646
1647   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1648
1649   STRIP_TYPE_NOPS (exp);
1650
1651   if (TREE_NO_WARNING (orig_exp))
1652     TREE_NO_WARNING (exp) = 1;
1653
1654   return build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 0);
1655 }
1656
1657 /* Perform the default conversion of arrays and functions to pointers.
1658    Return the result of converting EXP.  For any other expression, just
1659    return EXP.  */
1660
1661 struct c_expr
1662 default_function_array_conversion (struct c_expr exp)
1663 {
1664   tree orig_exp = exp.value;
1665   tree type = TREE_TYPE (exp.value);
1666   enum tree_code code = TREE_CODE (type);
1667
1668   switch (code)
1669     {
1670     case ARRAY_TYPE:
1671       {
1672         bool not_lvalue = false;
1673         bool lvalue_array_p;
1674
1675         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1676                 || CONVERT_EXPR_P (exp.value))
1677                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1678           {
1679             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1680               not_lvalue = true;
1681             exp.value = TREE_OPERAND (exp.value, 0);
1682           }
1683
1684         if (TREE_NO_WARNING (orig_exp))
1685           TREE_NO_WARNING (exp.value) = 1;
1686
1687         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1688         if (!flag_isoc99 && !lvalue_array_p)
1689           {
1690             /* Before C99, non-lvalue arrays do not decay to pointers.
1691                Normally, using such an array would be invalid; but it can
1692                be used correctly inside sizeof or as a statement expression.
1693                Thus, do not give an error here; an error will result later.  */
1694             return exp;
1695           }
1696
1697         exp.value = array_to_pointer_conversion (exp.value);
1698       }
1699       break;
1700     case FUNCTION_TYPE:
1701       exp.value = function_to_pointer_conversion (exp.value);
1702       break;
1703     default:
1704       break;
1705     }
1706
1707   return exp;
1708 }
1709
1710
1711 /* EXP is an expression of integer type.  Apply the integer promotions
1712    to it and return the promoted value.  */
1713
1714 tree
1715 perform_integral_promotions (tree exp)
1716 {
1717   tree type = TREE_TYPE (exp);
1718   enum tree_code code = TREE_CODE (type);
1719
1720   gcc_assert (INTEGRAL_TYPE_P (type));
1721
1722   /* Normally convert enums to int,
1723      but convert wide enums to something wider.  */
1724   if (code == ENUMERAL_TYPE)
1725     {
1726       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1727                                           TYPE_PRECISION (integer_type_node)),
1728                                      ((TYPE_PRECISION (type)
1729                                        >= TYPE_PRECISION (integer_type_node))
1730                                       && TYPE_UNSIGNED (type)));
1731
1732       return convert (type, exp);
1733     }
1734
1735   /* ??? This should no longer be needed now bit-fields have their
1736      proper types.  */
1737   if (TREE_CODE (exp) == COMPONENT_REF
1738       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1739       /* If it's thinner than an int, promote it like a
1740          c_promoting_integer_type_p, otherwise leave it alone.  */
1741       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1742                                TYPE_PRECISION (integer_type_node)))
1743     return convert (integer_type_node, exp);
1744
1745   if (c_promoting_integer_type_p (type))
1746     {
1747       /* Preserve unsignedness if not really getting any wider.  */
1748       if (TYPE_UNSIGNED (type)
1749           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1750         return convert (unsigned_type_node, exp);
1751
1752       return convert (integer_type_node, exp);
1753     }
1754
1755   return exp;
1756 }
1757
1758
1759 /* Perform default promotions for C data used in expressions.
1760    Enumeral types or short or char are converted to int.
1761    In addition, manifest constants symbols are replaced by their values.  */
1762
1763 tree
1764 default_conversion (tree exp)
1765 {
1766   tree orig_exp;
1767   tree type = TREE_TYPE (exp);
1768   enum tree_code code = TREE_CODE (type);
1769   tree promoted_type;
1770
1771   /* Functions and arrays have been converted during parsing.  */
1772   gcc_assert (code != FUNCTION_TYPE);
1773   if (code == ARRAY_TYPE)
1774     return exp;
1775
1776   /* Constants can be used directly unless they're not loadable.  */
1777   if (TREE_CODE (exp) == CONST_DECL)
1778     exp = DECL_INITIAL (exp);
1779
1780   /* Strip no-op conversions.  */
1781   orig_exp = exp;
1782   STRIP_TYPE_NOPS (exp);
1783
1784   if (TREE_NO_WARNING (orig_exp))
1785     TREE_NO_WARNING (exp) = 1;
1786
1787   if (code == VOID_TYPE)
1788     {
1789       error ("void value not ignored as it ought to be");
1790       return error_mark_node;
1791     }
1792
1793   exp = require_complete_type (exp);
1794   if (exp == error_mark_node)
1795     return error_mark_node;
1796
1797   promoted_type = targetm.promoted_type (type);
1798   if (promoted_type)
1799     return convert (promoted_type, exp);
1800
1801   if (INTEGRAL_TYPE_P (type))
1802     return perform_integral_promotions (exp);
1803
1804   return exp;
1805 }
1806 \f
1807 /* Look up COMPONENT in a structure or union DECL.
1808
1809    If the component name is not found, returns NULL_TREE.  Otherwise,
1810    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1811    stepping down the chain to the component, which is in the last
1812    TREE_VALUE of the list.  Normally the list is of length one, but if
1813    the component is embedded within (nested) anonymous structures or
1814    unions, the list steps down the chain to the component.  */
1815
1816 static tree
1817 lookup_field (tree decl, tree component)
1818 {
1819   tree type = TREE_TYPE (decl);
1820   tree field;
1821
1822   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1823      to the field elements.  Use a binary search on this array to quickly
1824      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1825      will always be set for structures which have many elements.  */
1826
1827   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1828     {
1829       int bot, top, half;
1830       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1831
1832       field = TYPE_FIELDS (type);
1833       bot = 0;
1834       top = TYPE_LANG_SPECIFIC (type)->s->len;
1835       while (top - bot > 1)
1836         {
1837           half = (top - bot + 1) >> 1;
1838           field = field_array[bot+half];
1839
1840           if (DECL_NAME (field) == NULL_TREE)
1841             {
1842               /* Step through all anon unions in linear fashion.  */
1843               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1844                 {
1845                   field = field_array[bot++];
1846                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1847                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1848                     {
1849                       tree anon = lookup_field (field, component);
1850
1851                       if (anon)
1852                         return tree_cons (NULL_TREE, field, anon);
1853                     }
1854                 }
1855
1856               /* Entire record is only anon unions.  */
1857               if (bot > top)
1858                 return NULL_TREE;
1859
1860               /* Restart the binary search, with new lower bound.  */
1861               continue;
1862             }
1863
1864           if (DECL_NAME (field) == component)
1865             break;
1866           if (DECL_NAME (field) < component)
1867             bot += half;
1868           else
1869             top = bot + half;
1870         }
1871
1872       if (DECL_NAME (field_array[bot]) == component)
1873         field = field_array[bot];
1874       else if (DECL_NAME (field) != component)
1875         return NULL_TREE;
1876     }
1877   else
1878     {
1879       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1880         {
1881           if (DECL_NAME (field) == NULL_TREE
1882               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1883                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1884             {
1885               tree anon = lookup_field (field, component);
1886
1887               if (anon)
1888                 return tree_cons (NULL_TREE, field, anon);
1889             }
1890
1891           if (DECL_NAME (field) == component)
1892             break;
1893         }
1894
1895       if (field == NULL_TREE)
1896         return NULL_TREE;
1897     }
1898
1899   return tree_cons (NULL_TREE, field, NULL_TREE);
1900 }
1901
1902 /* Make an expression to refer to the COMPONENT field of
1903    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1904
1905 tree
1906 build_component_ref (tree datum, tree component)
1907 {
1908   tree type = TREE_TYPE (datum);
1909   enum tree_code code = TREE_CODE (type);
1910   tree field = NULL;
1911   tree ref;
1912   bool datum_lvalue = lvalue_p (datum);
1913
1914   if (!objc_is_public (datum, component))
1915     return error_mark_node;
1916
1917   /* See if there is a field or component with name COMPONENT.  */
1918
1919   if (code == RECORD_TYPE || code == UNION_TYPE)
1920     {
1921       if (!COMPLETE_TYPE_P (type))
1922         {
1923           c_incomplete_type_error (NULL_TREE, type);
1924           return error_mark_node;
1925         }
1926
1927       field = lookup_field (datum, component);
1928
1929       if (!field)
1930         {
1931           error ("%qT has no member named %qE", type, component);
1932           return error_mark_node;
1933         }
1934
1935       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1936          This might be better solved in future the way the C++ front
1937          end does it - by giving the anonymous entities each a
1938          separate name and type, and then have build_component_ref
1939          recursively call itself.  We can't do that here.  */
1940       do
1941         {
1942           tree subdatum = TREE_VALUE (field);
1943           int quals;
1944           tree subtype;
1945           bool use_datum_quals;
1946
1947           if (TREE_TYPE (subdatum) == error_mark_node)
1948             return error_mark_node;
1949
1950           /* If this is an rvalue, it does not have qualifiers in C
1951              standard terms and we must avoid propagating such
1952              qualifiers down to a non-lvalue array that is then
1953              converted to a pointer.  */
1954           use_datum_quals = (datum_lvalue
1955                              || TREE_CODE (TREE_TYPE (subdatum)) != ARRAY_TYPE);
1956
1957           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1958           if (use_datum_quals)
1959             quals |= TYPE_QUALS (TREE_TYPE (datum));
1960           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1961
1962           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1963                         NULL_TREE);
1964           if (TREE_READONLY (subdatum)
1965               || (use_datum_quals && TREE_READONLY (datum)))
1966             TREE_READONLY (ref) = 1;
1967           if (TREE_THIS_VOLATILE (subdatum)
1968               || (use_datum_quals && TREE_THIS_VOLATILE (datum)))
1969             TREE_THIS_VOLATILE (ref) = 1;
1970
1971           if (TREE_DEPRECATED (subdatum))
1972             warn_deprecated_use (subdatum, NULL_TREE);
1973
1974           datum = ref;
1975
1976           field = TREE_CHAIN (field);
1977         }
1978       while (field);
1979
1980       return ref;
1981     }
1982   else if (code != ERROR_MARK)
1983     error ("request for member %qE in something not a structure or union",
1984            component);
1985
1986   return error_mark_node;
1987 }
1988 \f
1989 /* Given an expression PTR for a pointer, return an expression
1990    for the value pointed to.
1991    ERRORSTRING is the name of the operator to appear in error messages.
1992
1993    LOC is the location to use for the generated tree.  */
1994
1995 tree
1996 build_indirect_ref (location_t loc, tree ptr, const char *errorstring)
1997 {
1998   tree pointer = default_conversion (ptr);
1999   tree type = TREE_TYPE (pointer);
2000   tree ref;
2001
2002   if (TREE_CODE (type) == POINTER_TYPE)
2003     {
2004       if (CONVERT_EXPR_P (pointer)
2005           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
2006         {
2007           /* If a warning is issued, mark it to avoid duplicates from
2008              the backend.  This only needs to be done at
2009              warn_strict_aliasing > 2.  */
2010           if (warn_strict_aliasing > 2)
2011             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
2012                                          type, TREE_OPERAND (pointer, 0)))
2013               TREE_NO_WARNING (pointer) = 1;
2014         }
2015
2016       if (TREE_CODE (pointer) == ADDR_EXPR
2017           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
2018               == TREE_TYPE (type)))
2019         {
2020           ref = TREE_OPERAND (pointer, 0);
2021           protected_set_expr_location (ref, loc);
2022           return ref;
2023         }
2024       else
2025         {
2026           tree t = TREE_TYPE (type);
2027
2028           ref = build1 (INDIRECT_REF, t, pointer);
2029
2030           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2031             {
2032               error_at (loc, "dereferencing pointer to incomplete type");
2033               return error_mark_node;
2034             }
2035           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2036             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2037
2038           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2039              so that we get the proper error message if the result is used
2040              to assign to.  Also, &* is supposed to be a no-op.
2041              And ANSI C seems to specify that the type of the result
2042              should be the const type.  */
2043           /* A de-reference of a pointer to const is not a const.  It is valid
2044              to change it via some other pointer.  */
2045           TREE_READONLY (ref) = TYPE_READONLY (t);
2046           TREE_SIDE_EFFECTS (ref)
2047             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2048           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2049           protected_set_expr_location (ref, loc);
2050           return ref;
2051         }
2052     }
2053   else if (TREE_CODE (pointer) != ERROR_MARK)
2054     error_at (loc,
2055               "invalid type argument of %qs (have %qT)", errorstring, type);
2056   return error_mark_node;
2057 }
2058
2059 /* This handles expressions of the form "a[i]", which denotes
2060    an array reference.
2061
2062    This is logically equivalent in C to *(a+i), but we may do it differently.
2063    If A is a variable or a member, we generate a primitive ARRAY_REF.
2064    This avoids forcing the array out of registers, and can work on
2065    arrays that are not lvalues (for example, members of structures returned
2066    by functions).
2067
2068    LOC is the location to use for the returned expression.  */
2069
2070 tree
2071 build_array_ref (tree array, tree index, location_t loc)
2072 {
2073   tree ret;
2074   bool swapped = false;
2075   if (TREE_TYPE (array) == error_mark_node
2076       || TREE_TYPE (index) == error_mark_node)
2077     return error_mark_node;
2078
2079   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2080       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2081     {
2082       tree temp;
2083       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2084           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2085         {
2086           error_at (loc, "subscripted value is neither array nor pointer");
2087           return error_mark_node;
2088         }
2089       temp = array;
2090       array = index;
2091       index = temp;
2092       swapped = true;
2093     }
2094
2095   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2096     {
2097       error_at (loc, "array subscript is not an integer");
2098       return error_mark_node;
2099     }
2100
2101   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2102     {
2103       error_at (loc, "subscripted value is pointer to function");
2104       return error_mark_node;
2105     }
2106
2107   /* ??? Existing practice has been to warn only when the char
2108      index is syntactically the index, not for char[array].  */
2109   if (!swapped)
2110      warn_array_subscript_with_type_char (index);
2111
2112   /* Apply default promotions *after* noticing character types.  */
2113   index = default_conversion (index);
2114
2115   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2116
2117   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2118     {
2119       tree rval, type;
2120
2121       /* An array that is indexed by a non-constant
2122          cannot be stored in a register; we must be able to do
2123          address arithmetic on its address.
2124          Likewise an array of elements of variable size.  */
2125       if (TREE_CODE (index) != INTEGER_CST
2126           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2127               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2128         {
2129           if (!c_mark_addressable (array))
2130             return error_mark_node;
2131         }
2132       /* An array that is indexed by a constant value which is not within
2133          the array bounds cannot be stored in a register either; because we
2134          would get a crash in store_bit_field/extract_bit_field when trying
2135          to access a non-existent part of the register.  */
2136       if (TREE_CODE (index) == INTEGER_CST
2137           && TYPE_DOMAIN (TREE_TYPE (array))
2138           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2139         {
2140           if (!c_mark_addressable (array))
2141             return error_mark_node;
2142         }
2143
2144       if (pedantic)
2145         {
2146           tree foo = array;
2147           while (TREE_CODE (foo) == COMPONENT_REF)
2148             foo = TREE_OPERAND (foo, 0);
2149           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2150             pedwarn (loc, OPT_pedantic,
2151                      "ISO C forbids subscripting %<register%> array");
2152           else if (!flag_isoc99 && !lvalue_p (foo))
2153             pedwarn (loc, OPT_pedantic,
2154                      "ISO C90 forbids subscripting non-lvalue array");
2155         }
2156
2157       type = TREE_TYPE (TREE_TYPE (array));
2158       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2159       /* Array ref is const/volatile if the array elements are
2160          or if the array is.  */
2161       TREE_READONLY (rval)
2162         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2163             | TREE_READONLY (array));
2164       TREE_SIDE_EFFECTS (rval)
2165         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2166             | TREE_SIDE_EFFECTS (array));
2167       TREE_THIS_VOLATILE (rval)
2168         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2169             /* This was added by rms on 16 Nov 91.
2170                It fixes  vol struct foo *a;  a->elts[1]
2171                in an inline function.
2172                Hope it doesn't break something else.  */
2173             | TREE_THIS_VOLATILE (array));
2174       ret = require_complete_type (rval);
2175       protected_set_expr_location (ret, loc);
2176       return ret;
2177     }
2178   else
2179     {
2180       tree ar = default_conversion (array);
2181
2182       if (ar == error_mark_node)
2183         return ar;
2184
2185       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2186       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2187
2188       return build_indirect_ref
2189         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2190          "array indexing");
2191     }
2192 }
2193 \f
2194 /* Build an external reference to identifier ID.  FUN indicates
2195    whether this will be used for a function call.  LOC is the source
2196    location of the identifier.  This sets *TYPE to the type of the
2197    identifier, which is not the same as the type of the returned value
2198    for CONST_DECLs defined as enum constants.  If the type of the
2199    identifier is not available, *TYPE is set to NULL.  */
2200 tree
2201 build_external_ref (tree id, int fun, location_t loc, tree *type)
2202 {
2203   tree ref;
2204   tree decl = lookup_name (id);
2205
2206   /* In Objective-C, an instance variable (ivar) may be preferred to
2207      whatever lookup_name() found.  */
2208   decl = objc_lookup_ivar (decl, id);
2209
2210   *type = NULL;
2211   if (decl && decl != error_mark_node)
2212     {
2213       ref = decl;
2214       *type = TREE_TYPE (ref);
2215     }
2216   else if (fun)
2217     /* Implicit function declaration.  */
2218     ref = implicitly_declare (id);
2219   else if (decl == error_mark_node)
2220     /* Don't complain about something that's already been
2221        complained about.  */
2222     return error_mark_node;
2223   else
2224     {
2225       undeclared_variable (id, loc);
2226       return error_mark_node;
2227     }
2228
2229   if (TREE_TYPE (ref) == error_mark_node)
2230     return error_mark_node;
2231
2232   if (TREE_DEPRECATED (ref))
2233     warn_deprecated_use (ref, NULL_TREE);
2234
2235   /* Recursive call does not count as usage.  */
2236   if (ref != current_function_decl)
2237     {
2238       TREE_USED (ref) = 1;
2239     }
2240
2241   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2242     {
2243       if (!in_sizeof && !in_typeof)
2244         C_DECL_USED (ref) = 1;
2245       else if (DECL_INITIAL (ref) == 0
2246                && DECL_EXTERNAL (ref)
2247                && !TREE_PUBLIC (ref))
2248         record_maybe_used_decl (ref);
2249     }
2250
2251   if (TREE_CODE (ref) == CONST_DECL)
2252     {
2253       used_types_insert (TREE_TYPE (ref));
2254
2255       if (warn_cxx_compat
2256           && TREE_CODE (TREE_TYPE (ref)) == ENUMERAL_TYPE
2257           && C_TYPE_DEFINED_IN_STRUCT (TREE_TYPE (ref)))
2258         {
2259           warning_at (loc, OPT_Wc___compat,
2260                       ("enum constant defined in struct or union "
2261                        "is not visible in C++"));
2262           inform (DECL_SOURCE_LOCATION (ref), "enum constant defined here");
2263         }
2264
2265       ref = DECL_INITIAL (ref);
2266       TREE_CONSTANT (ref) = 1;
2267     }
2268   else if (current_function_decl != 0
2269            && !DECL_FILE_SCOPE_P (current_function_decl)
2270            && (TREE_CODE (ref) == VAR_DECL
2271                || TREE_CODE (ref) == PARM_DECL
2272                || TREE_CODE (ref) == FUNCTION_DECL))
2273     {
2274       tree context = decl_function_context (ref);
2275
2276       if (context != 0 && context != current_function_decl)
2277         DECL_NONLOCAL (ref) = 1;
2278     }
2279   /* C99 6.7.4p3: An inline definition of a function with external
2280      linkage ... shall not contain a reference to an identifier with
2281      internal linkage.  */
2282   else if (current_function_decl != 0
2283            && DECL_DECLARED_INLINE_P (current_function_decl)
2284            && DECL_EXTERNAL (current_function_decl)
2285            && VAR_OR_FUNCTION_DECL_P (ref)
2286            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2287            && ! TREE_PUBLIC (ref)
2288            && DECL_CONTEXT (ref) != current_function_decl)
2289     record_inline_static (loc, current_function_decl, ref,
2290                           csi_internal);
2291
2292   return ref;
2293 }
2294
2295 /* Record details of decls possibly used inside sizeof or typeof.  */
2296 struct maybe_used_decl
2297 {
2298   /* The decl.  */
2299   tree decl;
2300   /* The level seen at (in_sizeof + in_typeof).  */
2301   int level;
2302   /* The next one at this level or above, or NULL.  */
2303   struct maybe_used_decl *next;
2304 };
2305
2306 static struct maybe_used_decl *maybe_used_decls;
2307
2308 /* Record that DECL, an undefined static function reference seen
2309    inside sizeof or typeof, might be used if the operand of sizeof is
2310    a VLA type or the operand of typeof is a variably modified
2311    type.  */
2312
2313 static void
2314 record_maybe_used_decl (tree decl)
2315 {
2316   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2317   t->decl = decl;
2318   t->level = in_sizeof + in_typeof;
2319   t->next = maybe_used_decls;
2320   maybe_used_decls = t;
2321 }
2322
2323 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2324    USED is false, just discard them.  If it is true, mark them used
2325    (if no longer inside sizeof or typeof) or move them to the next
2326    level up (if still inside sizeof or typeof).  */
2327
2328 void
2329 pop_maybe_used (bool used)
2330 {
2331   struct maybe_used_decl *p = maybe_used_decls;
2332   int cur_level = in_sizeof + in_typeof;
2333   while (p && p->level > cur_level)
2334     {
2335       if (used)
2336         {
2337           if (cur_level == 0)
2338             C_DECL_USED (p->decl) = 1;
2339           else
2340             p->level = cur_level;
2341         }
2342       p = p->next;
2343     }
2344   if (!used || cur_level == 0)
2345     maybe_used_decls = p;
2346 }
2347
2348 /* Return the result of sizeof applied to EXPR.  */
2349
2350 struct c_expr
2351 c_expr_sizeof_expr (struct c_expr expr)
2352 {
2353   struct c_expr ret;
2354   if (expr.value == error_mark_node)
2355     {
2356       ret.value = error_mark_node;
2357       ret.original_code = ERROR_MARK;
2358       ret.original_type = NULL;
2359       pop_maybe_used (false);
2360     }
2361   else
2362     {
2363       bool expr_const_operands = true;
2364       tree folded_expr = c_fully_fold (expr.value, require_constant_value,
2365                                        &expr_const_operands);
2366       ret.value = c_sizeof (TREE_TYPE (folded_expr));
2367       ret.original_code = ERROR_MARK;
2368       ret.original_type = NULL;
2369       if (c_vla_type_p (TREE_TYPE (folded_expr)))
2370         {
2371           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2372           ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2373                               folded_expr, ret.value);
2374           C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !expr_const_operands;
2375         }
2376       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (folded_expr)));
2377     }
2378   return ret;
2379 }
2380
2381 /* Return the result of sizeof applied to T, a structure for the type
2382    name passed to sizeof (rather than the type itself).  */
2383
2384 struct c_expr
2385 c_expr_sizeof_type (struct c_type_name *t)
2386 {
2387   tree type;
2388   struct c_expr ret;
2389   tree type_expr = NULL_TREE;
2390   bool type_expr_const = true;
2391   type = groktypename (t, &type_expr, &type_expr_const);
2392   ret.value = c_sizeof (type);
2393   ret.original_code = ERROR_MARK;
2394   ret.original_type = NULL;
2395   if ((type_expr || TREE_CODE (ret.value) == INTEGER_CST)
2396       && c_vla_type_p (type))
2397     {
2398       /* If the type is a [*] array, it is a VLA but is represented as
2399          having a size of zero.  In such a case we must ensure that
2400          the result of sizeof does not get folded to a constant by
2401          c_fully_fold, because if the size is evaluated the result is
2402          not constant and so constraints on zero or negative size
2403          arrays must not be applied when this sizeof call is inside
2404          another array declarator.  */
2405       if (!type_expr)
2406         type_expr = integer_zero_node;
2407       ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2408                           type_expr, ret.value);
2409       C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !type_expr_const;
2410     }
2411   pop_maybe_used (type != error_mark_node
2412                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2413   return ret;
2414 }
2415
2416 /* Build a function call to function FUNCTION with parameters PARAMS.
2417    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2418    TREE_VALUE of each node is a parameter-expression.
2419    FUNCTION's data type may be a function type or a pointer-to-function.  */
2420
2421 tree
2422 build_function_call (tree function, tree params)
2423 {
2424   VEC(tree,gc) *vec;
2425   tree ret;
2426
2427   vec = VEC_alloc (tree, gc, list_length (params));
2428   for (; params; params = TREE_CHAIN (params))
2429     VEC_quick_push (tree, vec, TREE_VALUE (params));
2430   ret = build_function_call_vec (function, vec, NULL);
2431   VEC_free (tree, gc, vec);
2432   return ret;
2433 }
2434
2435 /* Build a function call to function FUNCTION with parameters PARAMS.
2436    ORIGTYPES, if not NULL, is a vector of types; each element is
2437    either NULL or the original type of the corresponding element in
2438    PARAMS.  The original type may differ from TREE_TYPE of the
2439    parameter for enums.  FUNCTION's data type may be a function type
2440    or pointer-to-function.  This function changes the elements of
2441    PARAMS.  */
2442
2443 tree
2444 build_function_call_vec (tree function, VEC(tree,gc) *params,
2445                          VEC(tree,gc) *origtypes)
2446 {
2447   tree fntype, fundecl = 0;
2448   tree name = NULL_TREE, result;
2449   tree tem;
2450   int nargs;
2451   tree *argarray;
2452
2453
2454   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2455   STRIP_TYPE_NOPS (function);
2456
2457   /* Convert anything with function type to a pointer-to-function.  */
2458   if (TREE_CODE (function) == FUNCTION_DECL)
2459     {
2460       /* Implement type-directed function overloading for builtins.
2461          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2462          handle all the type checking.  The result is a complete expression
2463          that implements this function call.  */
2464       tem = resolve_overloaded_builtin (function, params);
2465       if (tem)
2466         return tem;
2467
2468       name = DECL_NAME (function);
2469       fundecl = function;
2470     }
2471   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2472     function = function_to_pointer_conversion (function);
2473
2474   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2475      expressions, like those used for ObjC messenger dispatches.  */
2476   if (!VEC_empty (tree, params))
2477     function = objc_rewrite_function_call (function,
2478                                            VEC_index (tree, params, 0));
2479
2480   function = c_fully_fold (function, false, NULL);
2481
2482   fntype = TREE_TYPE (function);
2483
2484   if (TREE_CODE (fntype) == ERROR_MARK)
2485     return error_mark_node;
2486
2487   if (!(TREE_CODE (fntype) == POINTER_TYPE
2488         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2489     {
2490       error ("called object %qE is not a function", function);
2491       return error_mark_node;
2492     }
2493
2494   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2495     current_function_returns_abnormally = 1;
2496
2497   /* fntype now gets the type of function pointed to.  */
2498   fntype = TREE_TYPE (fntype);
2499
2500   /* Convert the parameters to the types declared in the
2501      function prototype, or apply default promotions.  */
2502
2503   nargs = convert_arguments (TYPE_ARG_TYPES (fntype), params, origtypes,
2504                              function, fundecl);
2505   if (nargs < 0)
2506     return error_mark_node;
2507
2508   /* Check that the function is called through a compatible prototype.
2509      If it is not, replace the call by a trap, wrapped up in a compound
2510      expression if necessary.  This has the nice side-effect to prevent
2511      the tree-inliner from generating invalid assignment trees which may
2512      blow up in the RTL expander later.  */
2513   if (CONVERT_EXPR_P (function)
2514       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2515       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2516       && !comptypes (fntype, TREE_TYPE (tem)))
2517     {
2518       tree return_type = TREE_TYPE (fntype);
2519       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2520                                        NULL_TREE);
2521       int i;
2522
2523       /* This situation leads to run-time undefined behavior.  We can't,
2524          therefore, simply error unless we can prove that all possible
2525          executions of the program must execute the code.  */
2526       if (warning (0, "function called through a non-compatible type"))
2527         /* We can, however, treat "undefined" any way we please.
2528            Call abort to encourage the user to fix the program.  */
2529         inform (input_location, "if this code is reached, the program will abort");
2530       /* Before the abort, allow the function arguments to exit or
2531          call longjmp.  */
2532       for (i = 0; i < nargs; i++)
2533         trap = build2 (COMPOUND_EXPR, void_type_node,
2534                        VEC_index (tree, params, i), trap);
2535
2536       if (VOID_TYPE_P (return_type))
2537         {
2538           if (TYPE_QUALS (return_type) != TYPE_UNQUALIFIED)
2539             pedwarn (input_location, 0,
2540                      "function with qualified void return type called");
2541           return trap;
2542         }
2543       else
2544         {
2545           tree rhs;
2546
2547           if (AGGREGATE_TYPE_P (return_type))
2548             rhs = build_compound_literal (return_type,
2549                                           build_constructor (return_type, 0),
2550                                           false);
2551           else
2552             rhs = fold_convert (return_type, integer_zero_node);
2553
2554           return require_complete_type (build2 (COMPOUND_EXPR, return_type,
2555                                                 trap, rhs));
2556         }
2557     }
2558
2559   argarray = VEC_address (tree, params);
2560
2561   /* Check that arguments to builtin functions match the expectations.  */
2562   if (fundecl
2563       && DECL_BUILT_IN (fundecl)
2564       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2565       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2566     return error_mark_node;
2567
2568   /* Check that the arguments to the function are valid.  */
2569   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2570                             TYPE_ARG_TYPES (fntype));
2571
2572   if (name != NULL_TREE
2573       && !strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10))
2574     {
2575       if (require_constant_value)
2576         result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2577                                                     function, nargs, argarray);
2578       else
2579         result = fold_build_call_array (TREE_TYPE (fntype),
2580                                         function, nargs, argarray);
2581       if (TREE_CODE (result) == NOP_EXPR
2582           && TREE_CODE (TREE_OPERAND (result, 0)) == INTEGER_CST)
2583         STRIP_TYPE_NOPS (result);
2584     }
2585   else
2586     result = build_call_array (TREE_TYPE (fntype),
2587                                function, nargs, argarray);
2588
2589   if (VOID_TYPE_P (TREE_TYPE (result)))
2590     {
2591       if (TYPE_QUALS (TREE_TYPE (result)) != TYPE_UNQUALIFIED)
2592         pedwarn (input_location, 0,
2593                  "function with qualified void return type called");
2594       return result;
2595     }
2596   return require_complete_type (result);
2597 }
2598 \f
2599 /* Convert the argument expressions in the vector VALUES
2600    to the types in the list TYPELIST.
2601
2602    If TYPELIST is exhausted, or when an element has NULL as its type,
2603    perform the default conversions.
2604
2605    ORIGTYPES is the original types of the expressions in VALUES.  This
2606    holds the type of enum values which have been converted to integral
2607    types.  It may be NULL.
2608
2609    FUNCTION is a tree for the called function.  It is used only for
2610    error messages, where it is formatted with %qE.
2611
2612    This is also where warnings about wrong number of args are generated.
2613
2614    Returns the actual number of arguments processed (which may be less
2615    than the length of VALUES in some error situations), or -1 on
2616    failure.  */
2617
2618 static int
2619 convert_arguments (tree typelist, VEC(tree,gc) *values,
2620                    VEC(tree,gc) *origtypes, tree function, tree fundecl)
2621 {
2622   tree typetail, val;
2623   unsigned int parmnum;
2624   const bool type_generic = fundecl
2625     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2626   bool type_generic_remove_excess_precision = false;
2627   tree selector;
2628
2629   /* Change pointer to function to the function itself for
2630      diagnostics.  */
2631   if (TREE_CODE (function) == ADDR_EXPR
2632       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2633     function = TREE_OPERAND (function, 0);
2634
2635   /* Handle an ObjC selector specially for diagnostics.  */
2636   selector = objc_message_selector ();
2637
2638   /* For type-generic built-in functions, determine whether excess
2639      precision should be removed (classification) or not
2640      (comparison).  */
2641   if (type_generic
2642       && DECL_BUILT_IN (fundecl)
2643       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL)
2644     {
2645       switch (DECL_FUNCTION_CODE (fundecl))
2646         {
2647         case BUILT_IN_ISFINITE:
2648         case BUILT_IN_ISINF:
2649         case BUILT_IN_ISINF_SIGN:
2650         case BUILT_IN_ISNAN:
2651         case BUILT_IN_ISNORMAL:
2652         case BUILT_IN_FPCLASSIFY:
2653           type_generic_remove_excess_precision = true;
2654           break;
2655
2656         default:
2657           type_generic_remove_excess_precision = false;
2658           break;
2659         }
2660     }
2661
2662   /* Scan the given expressions and types, producing individual
2663      converted arguments.  */
2664
2665   for (typetail = typelist, parmnum = 0;
2666        VEC_iterate (tree, values, parmnum, val);
2667        ++parmnum)
2668     {
2669       tree type = typetail ? TREE_VALUE (typetail) : 0;
2670       tree valtype = TREE_TYPE (val);
2671       tree rname = function;
2672       int argnum = parmnum + 1;
2673       const char *invalid_func_diag;
2674       bool excess_precision = false;
2675       bool npc;
2676       tree parmval;
2677
2678       if (type == void_type_node)
2679         {
2680           error ("too many arguments to function %qE", function);
2681           return parmnum;
2682         }
2683
2684       if (selector && argnum > 2)
2685         {
2686           rname = selector;
2687           argnum -= 2;
2688         }
2689
2690       npc = null_pointer_constant_p (val);
2691
2692       /* If there is excess precision and a prototype, convert once to
2693          the required type rather than converting via the semantic
2694          type.  Likewise without a prototype a float value represented
2695          as long double should be converted once to double.  But for
2696          type-generic classification functions excess precision must
2697          be removed here.  */
2698       if (TREE_CODE (val) == EXCESS_PRECISION_EXPR
2699           && (type || !type_generic || !type_generic_remove_excess_precision))
2700         {
2701           val = TREE_OPERAND (val, 0);
2702           excess_precision = true;
2703         }
2704       val = c_fully_fold (val, false, NULL);
2705       STRIP_TYPE_NOPS (val);
2706
2707       val = require_complete_type (val);
2708
2709       if (type != 0)
2710         {
2711           /* Formal parm type is specified by a function prototype.  */
2712
2713           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2714             {
2715               error ("type of formal parameter %d is incomplete", parmnum + 1);
2716               parmval = val;
2717             }
2718           else
2719             {
2720               tree origtype;
2721
2722               /* Optionally warn about conversions that
2723                  differ from the default conversions.  */
2724               if (warn_traditional_conversion || warn_traditional)
2725                 {
2726                   unsigned int formal_prec = TYPE_PRECISION (type);
2727
2728                   if (INTEGRAL_TYPE_P (type)
2729                       && TREE_CODE (valtype) == REAL_TYPE)
2730                     warning (0, "passing argument %d of %qE as integer "
2731                              "rather than floating due to prototype",
2732                              argnum, rname);
2733                   if (INTEGRAL_TYPE_P (type)
2734                       && TREE_CODE (valtype) == COMPLEX_TYPE)
2735                     warning (0, "passing argument %d of %qE as integer "
2736                              "rather than complex due to prototype",
2737                              argnum, rname);
2738                   else if (TREE_CODE (type) == COMPLEX_TYPE
2739                            && TREE_CODE (valtype) == REAL_TYPE)
2740                     warning (0, "passing argument %d of %qE as complex "
2741                              "rather than floating due to prototype",
2742                              argnum, rname);
2743                   else if (TREE_CODE (type) == REAL_TYPE
2744                            && INTEGRAL_TYPE_P (valtype))
2745                     warning (0, "passing argument %d of %qE as floating "
2746                              "rather than integer due to prototype",
2747                              argnum, rname);
2748                   else if (TREE_CODE (type) == COMPLEX_TYPE
2749                            && INTEGRAL_TYPE_P (valtype))
2750                     warning (0, "passing argument %d of %qE as complex "
2751                              "rather than integer due to prototype",
2752                              argnum, rname);
2753                   else if (TREE_CODE (type) == REAL_TYPE
2754                            && TREE_CODE (valtype) == COMPLEX_TYPE)
2755                     warning (0, "passing argument %d of %qE as floating "
2756                              "rather than complex due to prototype",
2757                              argnum, rname);
2758                   /* ??? At some point, messages should be written about
2759                      conversions between complex types, but that's too messy
2760                      to do now.  */
2761                   else if (TREE_CODE (type) == REAL_TYPE
2762                            && TREE_CODE (valtype) == REAL_TYPE)
2763                     {
2764                       /* Warn if any argument is passed as `float',
2765                          since without a prototype it would be `double'.  */
2766                       if (formal_prec == TYPE_PRECISION (float_type_node)
2767                           && type != dfloat32_type_node)
2768                         warning (0, "passing argument %d of %qE as %<float%> "
2769                                  "rather than %<double%> due to prototype",
2770                                  argnum, rname);
2771
2772                       /* Warn if mismatch between argument and prototype
2773                          for decimal float types.  Warn of conversions with
2774                          binary float types and of precision narrowing due to
2775                          prototype. */
2776                       else if (type != valtype
2777                                && (type == dfloat32_type_node
2778                                    || type == dfloat64_type_node
2779                                    || type == dfloat128_type_node
2780                                    || valtype == dfloat32_type_node
2781                                    || valtype == dfloat64_type_node
2782                                    || valtype == dfloat128_type_node)
2783                                && (formal_prec
2784                                    <= TYPE_PRECISION (valtype)
2785                                    || (type == dfloat128_type_node
2786                                        && (valtype
2787                                            != dfloat64_type_node
2788                                            && (valtype
2789                                                != dfloat32_type_node)))
2790                                    || (type == dfloat64_type_node
2791                                        && (valtype
2792                                            != dfloat32_type_node))))
2793                         warning (0, "passing argument %d of %qE as %qT "
2794                                  "rather than %qT due to prototype",
2795                                  argnum, rname, type, valtype);
2796
2797                     }
2798                   /* Detect integer changing in width or signedness.
2799                      These warnings are only activated with
2800                      -Wtraditional-conversion, not with -Wtraditional.  */
2801                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2802                            && INTEGRAL_TYPE_P (valtype))
2803                     {
2804                       tree would_have_been = default_conversion (val);
2805                       tree type1 = TREE_TYPE (would_have_been);
2806
2807                       if (TREE_CODE (type) == ENUMERAL_TYPE
2808                           && (TYPE_MAIN_VARIANT (type)
2809                               == TYPE_MAIN_VARIANT (valtype)))
2810                         /* No warning if function asks for enum
2811                            and the actual arg is that enum type.  */
2812                         ;
2813                       else if (formal_prec != TYPE_PRECISION (type1))
2814                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2815                                  "with different width due to prototype",
2816                                  argnum, rname);
2817                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2818                         ;
2819                       /* Don't complain if the formal parameter type
2820                          is an enum, because we can't tell now whether
2821                          the value was an enum--even the same enum.  */
2822                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2823                         ;
2824                       else if (TREE_CODE (val) == INTEGER_CST
2825                                && int_fits_type_p (val, type))
2826                         /* Change in signedness doesn't matter
2827                            if a constant value is unaffected.  */
2828                         ;
2829                       /* If the value is extended from a narrower
2830                          unsigned type, it doesn't matter whether we
2831                          pass it as signed or unsigned; the value
2832                          certainly is the same either way.  */
2833                       else if (TYPE_PRECISION (valtype) < TYPE_PRECISION (type)
2834                                && TYPE_UNSIGNED (valtype))
2835                         ;
2836                       else if (TYPE_UNSIGNED (type))
2837                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2838                                  "as unsigned due to prototype",
2839                                  argnum, rname);
2840                       else
2841                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2842                                  "as signed due to prototype", argnum, rname);
2843                     }
2844                 }
2845
2846               /* Possibly restore an EXCESS_PRECISION_EXPR for the
2847                  sake of better warnings from convert_and_check.  */
2848               if (excess_precision)
2849                 val = build1 (EXCESS_PRECISION_EXPR, valtype, val);
2850               origtype = (origtypes == NULL
2851                           ? NULL_TREE
2852                           : VEC_index (tree, origtypes, parmnum));
2853               parmval = convert_for_assignment (type, val, origtype,
2854                                                 ic_argpass, npc,
2855                                                 fundecl, function,
2856                                                 parmnum + 1);
2857
2858               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2859                   && INTEGRAL_TYPE_P (type)
2860                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2861                 parmval = default_conversion (parmval);
2862             }
2863         }
2864       else if (TREE_CODE (valtype) == REAL_TYPE
2865                && (TYPE_PRECISION (valtype)
2866                    < TYPE_PRECISION (double_type_node))
2867                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (valtype)))
2868         {
2869           if (type_generic)
2870             parmval = val;
2871           else
2872             /* Convert `float' to `double'.  */
2873             parmval = convert (double_type_node, val);
2874         }
2875       else if (excess_precision && !type_generic)
2876         /* A "double" argument with excess precision being passed
2877            without a prototype or in variable arguments.  */
2878         parmval = convert (valtype, val);
2879       else if ((invalid_func_diag =
2880                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2881         {
2882           error (invalid_func_diag);
2883           return -1;
2884         }
2885       else
2886         /* Convert `short' and `char' to full-size `int'.  */
2887         parmval = default_conversion (val);
2888
2889       VEC_replace (tree, values, parmnum, parmval);
2890
2891       if (typetail)
2892         typetail = TREE_CHAIN (typetail);
2893     }
2894
2895   gcc_assert (parmnum == VEC_length (tree, values));
2896
2897   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2898     {
2899       error ("too few arguments to function %qE", function);
2900       return -1;
2901     }
2902
2903   return parmnum;
2904 }
2905 \f
2906 /* This is the entry point used by the parser to build unary operators
2907    in the input.  CODE, a tree_code, specifies the unary operator, and
2908    ARG is the operand.  For unary plus, the C parser currently uses
2909    CONVERT_EXPR for code.
2910
2911    LOC is the location to use for the tree generated.
2912 */
2913
2914 struct c_expr
2915 parser_build_unary_op (enum tree_code code, struct c_expr arg, location_t loc)
2916 {
2917   struct c_expr result;
2918
2919   result.value = build_unary_op (loc, code, arg.value, 0);
2920   result.original_code = code;
2921   result.original_type = NULL;
2922
2923   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2924     overflow_warning (result.value);
2925
2926   return result;
2927 }
2928
2929 /* This is the entry point used by the parser to build binary operators
2930    in the input.  CODE, a tree_code, specifies the binary operator, and
2931    ARG1 and ARG2 are the operands.  In addition to constructing the
2932    expression, we check for operands that were written with other binary
2933    operators in a way that is likely to confuse the user.
2934
2935    LOCATION is the location of the binary operator.  */
2936
2937 struct c_expr
2938 parser_build_binary_op (location_t location, enum tree_code code,
2939                         struct c_expr arg1, struct c_expr arg2)
2940 {
2941   struct c_expr result;
2942
2943   enum tree_code code1 = arg1.original_code;
2944   enum tree_code code2 = arg2.original_code;
2945   tree type1 = (arg1.original_type
2946                 ? arg1.original_type
2947                 : TREE_TYPE (arg1.value));
2948   tree type2 = (arg2.original_type
2949                 ? arg2.original_type
2950                 : TREE_TYPE (arg2.value));
2951
2952   result.value = build_binary_op (location, code,
2953                                   arg1.value, arg2.value, 1);
2954   result.original_code = code;
2955   result.original_type = NULL;
2956
2957   if (TREE_CODE (result.value) == ERROR_MARK)
2958     return result;
2959
2960   if (location != UNKNOWN_LOCATION)
2961     protected_set_expr_location (result.value, location);
2962
2963   /* Check for cases such as x+y<<z which users are likely
2964      to misinterpret.  */
2965   if (warn_parentheses)
2966     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
2967
2968   if (warn_logical_op)
2969     warn_logical_operator (input_location, code, TREE_TYPE (result.value),
2970                            code1, arg1.value, code2, arg2.value);
2971
2972   /* Warn about comparisons against string literals, with the exception
2973      of testing for equality or inequality of a string literal with NULL.  */
2974   if (code == EQ_EXPR || code == NE_EXPR)
2975     {
2976       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2977           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2978         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2979     }
2980   else if (TREE_CODE_CLASS (code) == tcc_comparison
2981            && (code1 == STRING_CST || code2 == STRING_CST))
2982     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2983
2984   if (TREE_OVERFLOW_P (result.value)
2985       && !TREE_OVERFLOW_P (arg1.value)
2986       && !TREE_OVERFLOW_P (arg2.value))
2987     overflow_warning (result.value);
2988
2989   /* Warn about comparisons of different enum types.  */
2990   if (warn_enum_compare
2991       && TREE_CODE_CLASS (code) == tcc_comparison
2992       && TREE_CODE (type1) == ENUMERAL_TYPE
2993       && TREE_CODE (type2) == ENUMERAL_TYPE
2994       && TYPE_MAIN_VARIANT (type1) != TYPE_MAIN_VARIANT (type2))
2995     warning_at (location, OPT_Wenum_compare,
2996                 "comparison between %qT and %qT",
2997                 type1, type2);
2998
2999   return result;
3000 }
3001 \f
3002 /* Return a tree for the difference of pointers OP0 and OP1.
3003    The resulting tree has type int.  */
3004
3005 static tree
3006 pointer_diff (tree op0, tree op1)
3007 {
3008   tree restype = ptrdiff_type_node;
3009
3010   tree target_type = TREE_TYPE (TREE_TYPE (op0));
3011   tree con0, con1, lit0, lit1;
3012   tree orig_op1 = op1;
3013
3014   if (TREE_CODE (target_type) == VOID_TYPE)
3015     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3016              "pointer of type %<void *%> used in subtraction");
3017   if (TREE_CODE (target_type) == FUNCTION_TYPE)
3018     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3019              "pointer to a function used in subtraction");
3020
3021   /* If the conversion to ptrdiff_type does anything like widening or
3022      converting a partial to an integral mode, we get a convert_expression
3023      that is in the way to do any simplifications.
3024      (fold-const.c doesn't know that the extra bits won't be needed.
3025      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
3026      different mode in place.)
3027      So first try to find a common term here 'by hand'; we want to cover
3028      at least the cases that occur in legal static initializers.  */
3029   if (CONVERT_EXPR_P (op0)
3030       && (TYPE_PRECISION (TREE_TYPE (op0))
3031           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
3032     con0 = TREE_OPERAND (op0, 0);
3033   else
3034     con0 = op0;
3035   if (CONVERT_EXPR_P (op1)
3036       && (TYPE_PRECISION (TREE_TYPE (op1))
3037           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
3038     con1 = TREE_OPERAND (op1, 0);
3039   else
3040     con1 = op1;
3041
3042   if (TREE_CODE (con0) == PLUS_EXPR)
3043     {
3044       lit0 = TREE_OPERAND (con0, 1);
3045       con0 = TREE_OPERAND (con0, 0);
3046     }
3047   else
3048     lit0 = integer_zero_node;
3049
3050   if (TREE_CODE (con1) == PLUS_EXPR)
3051     {
3052       lit1 = TREE_OPERAND (con1, 1);
3053       con1 = TREE_OPERAND (con1, 0);
3054     }
3055   else
3056     lit1 = integer_zero_node;
3057
3058   if (operand_equal_p (con0, con1, 0))
3059     {
3060       op0 = lit0;
3061       op1 = lit1;
3062     }
3063
3064
3065   /* First do the subtraction as integers;
3066      then drop through to build the divide operator.
3067      Do not do default conversions on the minus operator
3068      in case restype is a short type.  */
3069
3070   op0 = build_binary_op (input_location,
3071                          MINUS_EXPR, convert (restype, op0),
3072                          convert (restype, op1), 0);
3073   /* This generates an error if op1 is pointer to incomplete type.  */
3074   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
3075     error ("arithmetic on pointer to an incomplete type");
3076
3077   /* This generates an error if op0 is pointer to incomplete type.  */
3078   op1 = c_size_in_bytes (target_type);
3079
3080   /* Divide by the size, in easiest possible way.  */
3081   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
3082 }
3083 \f
3084 /* Construct and perhaps optimize a tree representation
3085    for a unary operation.  CODE, a tree_code, specifies the operation
3086    and XARG is the operand.
3087    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
3088    the default promotions (such as from short to int).
3089    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
3090    allows non-lvalues; this is only used to handle conversion of non-lvalue
3091    arrays to pointers in C99.
3092
3093    LOCATION is the location of the operator.  */
3094
3095 tree
3096 build_unary_op (location_t location,
3097                 enum tree_code code, tree xarg, int flag)
3098 {
3099   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3100   tree arg = xarg;
3101   tree argtype = 0;
3102   enum tree_code typecode;
3103   tree val;
3104   tree ret = error_mark_node;
3105   tree eptype = NULL_TREE;
3106   int noconvert = flag;
3107   const char *invalid_op_diag;
3108   bool int_operands;
3109
3110   int_operands = EXPR_INT_CONST_OPERANDS (xarg);
3111   if (int_operands)
3112     arg = remove_c_maybe_const_expr (arg);
3113
3114   if (code != ADDR_EXPR)
3115     arg = require_complete_type (arg);
3116
3117   typecode = TREE_CODE (TREE_TYPE (arg));
3118   if (typecode == ERROR_MARK)
3119     return error_mark_node;
3120   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
3121     typecode = INTEGER_TYPE;
3122
3123   if ((invalid_op_diag
3124        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
3125     {
3126       error_at (location, invalid_op_diag);
3127       return error_mark_node;
3128     }
3129
3130   if (TREE_CODE (arg) == EXCESS_PRECISION_EXPR)
3131     {
3132       eptype = TREE_TYPE (arg);
3133       arg = TREE_OPERAND (arg, 0);
3134     }
3135
3136   switch (code)
3137     {
3138     case CONVERT_EXPR:
3139       /* This is used for unary plus, because a CONVERT_EXPR
3140          is enough to prevent anybody from looking inside for
3141          associativity, but won't generate any code.  */
3142       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3143             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3144             || typecode == VECTOR_TYPE))
3145         {
3146           error_at (location, "wrong type argument to unary plus");
3147           return error_mark_node;
3148         }
3149       else if (!noconvert)
3150         arg = default_conversion (arg);
3151       arg = non_lvalue (arg);
3152       break;
3153
3154     case NEGATE_EXPR:
3155       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3156             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3157             || typecode == VECTOR_TYPE))
3158         {
3159           error_at (location, "wrong type argument to unary minus");
3160           return error_mark_node;
3161         }
3162       else if (!noconvert)
3163         arg = default_conversion (arg);
3164       break;
3165
3166     case BIT_NOT_EXPR:
3167       /* ~ works on integer types and non float vectors. */
3168       if (typecode == INTEGER_TYPE
3169           || (typecode == VECTOR_TYPE
3170               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
3171         {
3172           if (!noconvert)
3173             arg = default_conversion (arg);
3174         }
3175       else if (typecode == COMPLEX_TYPE)
3176         {
3177           code = CONJ_EXPR;
3178           pedwarn (location, OPT_pedantic,
3179                    "ISO C does not support %<~%> for complex conjugation");
3180           if (!noconvert)
3181             arg = default_conversion (arg);
3182         }
3183       else
3184         {
3185           error_at (location, "wrong type argument to bit-complement");
3186           return error_mark_node;
3187         }
3188       break;
3189
3190     case ABS_EXPR:
3191       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
3192         {
3193           error_at (location, "wrong type argument to abs");
3194           return error_mark_node;
3195         }
3196       else if (!noconvert)
3197         arg = default_conversion (arg);
3198       break;
3199
3200     case CONJ_EXPR:
3201       /* Conjugating a real value is a no-op, but allow it anyway.  */
3202       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3203             || typecode == COMPLEX_TYPE))
3204         {
3205           error_at (location, "wrong type argument to conjugation");
3206           return error_mark_node;
3207         }
3208       else if (!noconvert)
3209         arg = default_conversion (arg);
3210       break;
3211
3212     case TRUTH_NOT_EXPR:
3213       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3214           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3215           && typecode != COMPLEX_TYPE)
3216         {
3217           error_at (location,
3218                     "wrong type argument to unary exclamation mark");
3219           return error_mark_node;
3220         }
3221       arg = c_objc_common_truthvalue_conversion (location, arg);
3222       ret = invert_truthvalue (arg);
3223       /* If the TRUTH_NOT_EXPR has been folded, reset the location.  */
3224       if (EXPR_P (ret) && EXPR_HAS_LOCATION (ret))
3225         location = EXPR_LOCATION (ret);
3226       goto return_build_unary_op;
3227
3228     case REALPART_EXPR:
3229       if (TREE_CODE (arg) == COMPLEX_CST)
3230         ret = TREE_REALPART (arg);
3231       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3232         ret = fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3233       else
3234         ret = arg;
3235       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3236         eptype = TREE_TYPE (eptype);
3237       goto return_build_unary_op;
3238
3239     case IMAGPART_EXPR:
3240       if (TREE_CODE (arg) == COMPLEX_CST)
3241         ret = TREE_IMAGPART (arg);
3242       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3243         ret = fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3244       else
3245         ret = omit_one_operand (TREE_TYPE (arg), integer_zero_node, arg);
3246       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3247         eptype = TREE_TYPE (eptype);
3248       goto return_build_unary_op;
3249
3250     case PREINCREMENT_EXPR:
3251     case POSTINCREMENT_EXPR:
3252     case PREDECREMENT_EXPR:
3253     case POSTDECREMENT_EXPR:
3254
3255       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3256         {
3257           tree inner = build_unary_op (location, code,
3258                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3259           if (inner == error_mark_node)
3260             return error_mark_node;
3261           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3262                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3263           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3264           C_MAYBE_CONST_EXPR_NON_CONST (ret) = 1;
3265           goto return_build_unary_op;
3266         }
3267
3268       /* Complain about anything that is not a true lvalue.  */
3269       if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3270                                   || code == POSTINCREMENT_EXPR)
3271                                  ? lv_increment
3272                                  : lv_decrement)))
3273         return error_mark_node;
3274
3275       if (warn_cxx_compat && TREE_CODE (TREE_TYPE (arg)) == ENUMERAL_TYPE)
3276         {
3277           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3278             warning_at (location, OPT_Wc___compat,
3279                         "increment of enumeration value is invalid in C++");
3280           else
3281             warning_at (location, OPT_Wc___compat,
3282                         "decrement of enumeration value is invalid in C++");
3283         }
3284
3285       /* Ensure the argument is fully folded inside any SAVE_EXPR.  */
3286       arg = c_fully_fold (arg, false, NULL);
3287
3288       /* Increment or decrement the real part of the value,
3289          and don't change the imaginary part.  */
3290       if (typecode == COMPLEX_TYPE)
3291         {
3292           tree real, imag;
3293
3294           pedwarn (location, OPT_pedantic,
3295                    "ISO C does not support %<++%> and %<--%> on complex types");
3296
3297           arg = stabilize_reference (arg);
3298           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3299           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3300           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3301           if (real == error_mark_node || imag == error_mark_node)
3302             return error_mark_node;
3303           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3304                         real, imag);
3305           goto return_build_unary_op;
3306         }
3307
3308       /* Report invalid types.  */
3309
3310       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3311           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3312         {
3313           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3314             error_at (location, "wrong type argument to increment");
3315           else
3316             error_at (location, "wrong type argument to decrement");
3317
3318           return error_mark_node;
3319         }
3320
3321       {
3322         tree inc;
3323
3324         argtype = TREE_TYPE (arg);
3325
3326         /* Compute the increment.  */
3327
3328         if (typecode == POINTER_TYPE)
3329           {
3330             /* If pointer target is an undefined struct,
3331                we just cannot know how to do the arithmetic.  */
3332             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3333               {
3334                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3335                   error_at (location,
3336                             "increment of pointer to unknown structure");
3337                 else
3338                   error_at (location,
3339                             "decrement of pointer to unknown structure");
3340               }
3341             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3342                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3343               {
3344                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3345                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3346                            "wrong type argument to increment");
3347                 else
3348                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3349                            "wrong type argument to decrement");
3350               }
3351
3352             inc = c_size_in_bytes (TREE_TYPE (argtype));
3353             inc = fold_convert (sizetype, inc);
3354           }
3355         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3356           {
3357             /* For signed fract types, we invert ++ to -- or
3358                -- to ++, and change inc from 1 to -1, because
3359                it is not possible to represent 1 in signed fract constants.
3360                For unsigned fract types, the result always overflows and
3361                we get an undefined (original) or the maximum value.  */
3362             if (code == PREINCREMENT_EXPR)
3363               code = PREDECREMENT_EXPR;
3364             else if (code == PREDECREMENT_EXPR)
3365               code = PREINCREMENT_EXPR;
3366             else if (code == POSTINCREMENT_EXPR)
3367               code = POSTDECREMENT_EXPR;
3368             else /* code == POSTDECREMENT_EXPR  */
3369               code = POSTINCREMENT_EXPR;
3370
3371             inc = integer_minus_one_node;
3372             inc = convert (argtype, inc);
3373           }
3374         else
3375           {
3376             inc = integer_one_node;
3377             inc = convert (argtype, inc);
3378           }
3379
3380         /* Report a read-only lvalue.  */
3381         if (TYPE_READONLY (argtype))
3382           {
3383             readonly_error (arg,
3384                             ((code == PREINCREMENT_EXPR
3385                               || code == POSTINCREMENT_EXPR)
3386                              ? lv_increment : lv_decrement));
3387             return error_mark_node;
3388           }
3389         else if (TREE_READONLY (arg))
3390           readonly_warning (arg,
3391                             ((code == PREINCREMENT_EXPR
3392                               || code == POSTINCREMENT_EXPR)
3393                              ? lv_increment : lv_decrement));
3394
3395         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3396           val = boolean_increment (code, arg);
3397         else
3398           val = build2 (code, TREE_TYPE (arg), arg, inc);
3399         TREE_SIDE_EFFECTS (val) = 1;
3400         if (TREE_CODE (val) != code)
3401           TREE_NO_WARNING (val) = 1;
3402         ret = val;
3403         goto return_build_unary_op;
3404       }
3405
3406     case ADDR_EXPR:
3407       /* Note that this operation never does default_conversion.  */
3408
3409       /* The operand of unary '&' must be an lvalue (which excludes
3410          expressions of type void), or, in C99, the result of a [] or
3411          unary '*' operator.  */
3412       if (VOID_TYPE_P (TREE_TYPE (arg))
3413           && TYPE_QUALS (TREE_TYPE (arg)) == TYPE_UNQUALIFIED
3414           && (TREE_CODE (arg) != INDIRECT_REF
3415               || !flag_isoc99))
3416         pedwarn (location, 0, "taking address of expression of type %<void%>");
3417
3418       /* Let &* cancel out to simplify resulting code.  */
3419       if (TREE_CODE (arg) == INDIRECT_REF)
3420         {
3421           /* Don't let this be an lvalue.  */
3422           if (lvalue_p (TREE_OPERAND (arg, 0)))
3423             return non_lvalue (TREE_OPERAND (arg, 0));
3424           ret = TREE_OPERAND (arg, 0);
3425           goto return_build_unary_op;
3426         }
3427
3428       /* For &x[y], return x+y */
3429       if (TREE_CODE (arg) == ARRAY_REF)
3430         {
3431           tree op0 = TREE_OPERAND (arg, 0);
3432           if (!c_mark_addressable (op0))
3433             return error_mark_node;
3434           return build_binary_op (location, PLUS_EXPR,
3435                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3436                                    ? array_to_pointer_conversion (op0)
3437                                    : op0),
3438                                   TREE_OPERAND (arg, 1), 1);
3439         }
3440
3441       /* Anything not already handled and not a true memory reference
3442          or a non-lvalue array is an error.  */
3443       else if (typecode != FUNCTION_TYPE && !flag
3444                && !lvalue_or_else (arg, lv_addressof))
3445         return error_mark_node;
3446
3447       /* Move address operations inside C_MAYBE_CONST_EXPR to simplify
3448          folding later.  */
3449       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3450         {
3451           tree inner = build_unary_op (location, code,
3452                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3453           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3454                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3455           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3456           C_MAYBE_CONST_EXPR_NON_CONST (ret)
3457             = C_MAYBE_CONST_EXPR_NON_CONST (arg);
3458           goto return_build_unary_op;
3459         }
3460
3461       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3462       argtype = TREE_TYPE (arg);
3463
3464       /* If the lvalue is const or volatile, merge that into the type
3465          to which the address will point.  Note that you can't get a
3466          restricted pointer by taking the address of something, so we
3467          only have to deal with `const' and `volatile' here.  */
3468       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3469           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3470           argtype = c_build_type_variant (argtype,
3471                                           TREE_READONLY (arg),
3472                                           TREE_THIS_VOLATILE (arg));
3473
3474       if (!c_mark_addressable (arg))
3475         return error_mark_node;
3476
3477       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3478                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3479
3480       argtype = build_pointer_type (argtype);
3481
3482       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3483          when we have proper support for integer constant expressions.  */
3484       val = get_base_address (arg);
3485       if (val && TREE_CODE (val) == INDIRECT_REF
3486           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3487         {
3488           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3489
3490           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3491           ret = fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3492           goto return_build_unary_op;
3493         }
3494
3495       val = build1 (ADDR_EXPR, argtype, arg);
3496
3497       ret = val;
3498       goto return_build_unary_op;
3499
3500     default:
3501       gcc_unreachable ();
3502     }
3503
3504   if (argtype == 0)
3505     argtype = TREE_TYPE (arg);
3506   if (TREE_CODE (arg) == INTEGER_CST)
3507     ret = (require_constant_value
3508            ? fold_build1_initializer (code, argtype, arg)
3509            : fold_build1 (code, argtype, arg));
3510   else
3511     ret = build1 (code, argtype, arg);
3512  return_build_unary_op:
3513   gcc_assert (ret != error_mark_node);
3514   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret)
3515       && !(TREE_CODE (xarg) == INTEGER_CST && !TREE_OVERFLOW (xarg)))
3516     ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
3517   else if (TREE_CODE (ret) != INTEGER_CST && int_operands)
3518     ret = note_integer_operands (ret);
3519   if (eptype)
3520     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3521   protected_set_expr_location (ret, location);
3522   return ret;
3523 }
3524
3525 /* Return nonzero if REF is an lvalue valid for this language.
3526    Lvalues can be assigned, unless their type has TYPE_READONLY.
3527    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3528
3529 bool
3530 lvalue_p (const_tree ref)
3531 {
3532   const enum tree_code code = TREE_CODE (ref);
3533
3534   switch (code)
3535     {
3536     case REALPART_EXPR:
3537     case IMAGPART_EXPR:
3538     case COMPONENT_REF:
3539       return lvalue_p (TREE_OPERAND (ref, 0));
3540
3541     case C_MAYBE_CONST_EXPR:
3542       return lvalue_p (TREE_OPERAND (ref, 1));
3543
3544     case COMPOUND_LITERAL_EXPR:
3545     case STRING_CST:
3546       return 1;
3547
3548     case INDIRECT_REF:
3549     case ARRAY_REF:
3550     case VAR_DECL:
3551     case PARM_DECL:
3552     case RESULT_DECL:
3553     case ERROR_MARK:
3554       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3555               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3556
3557     case BIND_EXPR:
3558       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3559
3560     default:
3561       return 0;
3562     }
3563 }
3564 \f
3565 /* Give an error for storing in something that is 'const'.  */
3566
3567 static void
3568 readonly_error (tree arg, enum lvalue_use use)
3569 {
3570   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3571               || use == lv_asm);
3572   /* Using this macro rather than (for example) arrays of messages
3573      ensures that all the format strings are checked at compile
3574      time.  */
3575 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3576                                    : (use == lv_increment ? (I)         \
3577                                    : (use == lv_decrement ? (D) : (AS))))
3578   if (TREE_CODE (arg) == COMPONENT_REF)
3579     {
3580       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3581         readonly_error (TREE_OPERAND (arg, 0), use);
3582       else
3583         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3584                              G_("increment of read-only member %qD"),
3585                              G_("decrement of read-only member %qD"),
3586                              G_("read-only member %qD used as %<asm%> output")),
3587                TREE_OPERAND (arg, 1));
3588     }
3589   else if (TREE_CODE (arg) == VAR_DECL)
3590     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3591                          G_("increment of read-only variable %qD"),
3592                          G_("decrement of read-only variable %qD"),
3593                          G_("read-only variable %qD used as %<asm%> output")),
3594            arg);
3595   else
3596     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3597                          G_("increment of read-only location %qE"),
3598                          G_("decrement of read-only location %qE"),
3599                          G_("read-only location %qE used as %<asm%> output")),
3600            arg);
3601 }
3602
3603 /* Give a warning for storing in something that is read-only in GCC
3604    terms but not const in ISO C terms.  */
3605
3606 static void
3607 readonly_warning (tree arg, enum lvalue_use use)
3608 {
3609   switch (use)
3610     {
3611     case lv_assign:
3612       warning (0, "assignment of read-only location %qE", arg);
3613       break;
3614     case lv_increment:
3615       warning (0, "increment of read-only location %qE", arg);
3616       break;
3617     case lv_decrement:
3618       warning (0, "decrement of read-only location %qE", arg);
3619       break;
3620     default:
3621       gcc_unreachable ();
3622     }
3623   return;
3624 }
3625
3626
3627 /* Return nonzero if REF is an lvalue valid for this language;
3628    otherwise, print an error message and return zero.  USE says
3629    how the lvalue is being used and so selects the error message.  */
3630
3631 static int
3632 lvalue_or_else (const_tree ref, enum lvalue_use use)
3633 {
3634   int win = lvalue_p (ref);
3635
3636   if (!win)
3637     lvalue_error (use);
3638
3639   return win;
3640 }
3641 \f
3642 /* Mark EXP saying that we need to be able to take the
3643    address of it; it should not be allocated in a register.
3644    Returns true if successful.  */
3645
3646 bool
3647 c_mark_addressable (tree exp)
3648 {
3649   tree x = exp;
3650
3651   while (1)
3652     switch (TREE_CODE (x))
3653       {
3654       case COMPONENT_REF:
3655         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3656           {
3657             error
3658               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3659             return false;
3660           }
3661
3662         /* ... fall through ...  */
3663
3664       case ADDR_EXPR:
3665       case ARRAY_REF:
3666       case REALPART_EXPR:
3667       case IMAGPART_EXPR:
3668         x = TREE_OPERAND (x, 0);
3669         break;
3670
3671       case COMPOUND_LITERAL_EXPR:
3672       case CONSTRUCTOR:
3673         TREE_ADDRESSABLE (x) = 1;
3674         return true;
3675
3676       case VAR_DECL:
3677       case CONST_DECL:
3678       case PARM_DECL:
3679       case RESULT_DECL:
3680         if (C_DECL_REGISTER (x)
3681             && DECL_NONLOCAL (x))
3682           {
3683             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3684               {
3685                 error
3686                   ("global register variable %qD used in nested function", x);
3687                 return false;
3688               }
3689             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3690           }
3691         else if (C_DECL_REGISTER (x))
3692           {
3693             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3694               error ("address of global register variable %qD requested", x);
3695             else
3696               error ("address of register variable %qD requested", x);
3697             return false;
3698           }
3699
3700         /* drops in */
3701       case FUNCTION_DECL:
3702         TREE_ADDRESSABLE (x) = 1;
3703         /* drops out */
3704       default:
3705         return true;
3706     }
3707 }
3708 \f
3709 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  If
3710    IFEXP_BCP then the condition is a call to __builtin_constant_p, and
3711    if folded to an integer constant then the unselected half may
3712    contain arbitrary operations not normally permitted in constant
3713    expressions.  */
3714
3715 tree
3716 build_conditional_expr (tree ifexp, bool ifexp_bcp, tree op1, tree op2)
3717 {
3718   tree type1;
3719   tree type2;
3720   enum tree_code code1;
3721   enum tree_code code2;
3722   tree result_type = NULL;
3723   tree ep_result_type = NULL;
3724   tree orig_op1 = op1, orig_op2 = op2;
3725   bool int_const, op1_int_operands, op2_int_operands, int_operands;
3726   bool ifexp_int_operands;
3727   tree ret;
3728   bool objc_ok;
3729
3730   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
3731   if (op1_int_operands)
3732     op1 = remove_c_maybe_const_expr (op1);
3733   op2_int_operands = EXPR_INT_CONST_OPERANDS (orig_op2);
3734   if (op2_int_operands)
3735     op2 = remove_c_maybe_const_expr (op2);
3736   ifexp_int_operands = EXPR_INT_CONST_OPERANDS (ifexp);
3737   if (ifexp_int_operands)
3738     ifexp = remove_c_maybe_const_expr (ifexp);
3739
3740   /* Promote both alternatives.  */
3741
3742   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3743     op1 = default_conversion (op1);
3744   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3745     op2 = default_conversion (op2);
3746
3747   if (TREE_CODE (ifexp) == ERROR_MARK
3748       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3749       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3750     return error_mark_node;
3751
3752   type1 = TREE_TYPE (op1);
3753   code1 = TREE_CODE (type1);
3754   type2 = TREE_TYPE (op2);
3755   code2 = TREE_CODE (type2);
3756
3757   /* C90 does not permit non-lvalue arrays in conditional expressions.
3758      In C99 they will be pointers by now.  */
3759   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3760     {
3761       error ("non-lvalue array in conditional expression");
3762       return error_mark_node;
3763     }
3764
3765   objc_ok = objc_compare_types (type1, type2, -3, NULL_TREE);
3766
3767   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
3768        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3769       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
3770           || code1 == COMPLEX_TYPE)
3771       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3772           || code2 == COMPLEX_TYPE))
3773     {
3774       ep_result_type = c_common_type (type1, type2);
3775       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
3776         {
3777           op1 = TREE_OPERAND (op1, 0);
3778           type1 = TREE_TYPE (op1);
3779           gcc_assert (TREE_CODE (type1) == code1);
3780         }
3781       if (TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3782         {
3783           op2 = TREE_OPERAND (op2, 0);
3784           type2 = TREE_TYPE (op2);
3785           gcc_assert (TREE_CODE (type2) == code2);
3786         }
3787     }
3788
3789   /* Quickly detect the usual case where op1 and op2 have the same type
3790      after promotion.  */
3791   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3792     {
3793       if (type1 == type2)
3794         result_type = type1;
3795       else
3796         result_type = TYPE_MAIN_VARIANT (type1);
3797     }
3798   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3799             || code1 == COMPLEX_TYPE)
3800            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3801                || code2 == COMPLEX_TYPE))
3802     {
3803       result_type = c_common_type (type1, type2);
3804
3805       /* If -Wsign-compare, warn here if type1 and type2 have
3806          different signedness.  We'll promote the signed to unsigned
3807          and later code won't know it used to be different.
3808          Do this check on the original types, so that explicit casts
3809          will be considered, but default promotions won't.  */
3810       if (!skip_evaluation)
3811         {
3812           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3813           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3814
3815           if (unsigned_op1 ^ unsigned_op2)
3816             {
3817               bool ovf;
3818
3819               /* Do not warn if the result type is signed, since the
3820                  signed type will only be chosen if it can represent
3821                  all the values of the unsigned type.  */
3822               if (!TYPE_UNSIGNED (result_type))
3823                 /* OK */;
3824               else
3825                 {
3826                   bool op1_maybe_const = true;
3827                   bool op2_maybe_const = true;
3828
3829                   /* Do not warn if the signed quantity is an
3830                      unsuffixed integer literal (or some static
3831                      constant expression involving such literals) and
3832                      it is non-negative.  This warning requires the
3833                      operands to be folded for best results, so do
3834                      that folding in this case even without
3835                      warn_sign_compare to avoid warning options
3836                      possibly affecting code generation.  */
3837                   op1 = c_fully_fold (op1, require_constant_value,
3838                                       &op1_maybe_const);
3839                   op2 = c_fully_fold (op2, require_constant_value,
3840                                       &op2_maybe_const);
3841
3842                   if (warn_sign_compare)
3843                     {
3844                       if ((unsigned_op2
3845                            && tree_expr_nonnegative_warnv_p (op1, &ovf))
3846                           || (unsigned_op1
3847                               && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3848                         /* OK */;
3849                       else
3850                         warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3851                     }
3852                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
3853                     {
3854                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
3855                                     NULL, op1);
3856                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
3857                     }
3858                   if (!op2_maybe_const || TREE_CODE (op2) != INTEGER_CST)
3859                     {
3860                       op2 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op2),
3861                                     NULL, op2);
3862                       C_MAYBE_CONST_EXPR_NON_CONST (op2) = !op2_maybe_const;
3863                     }
3864                 }
3865             }
3866         }
3867     }
3868   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3869     {
3870       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3871         pedwarn (input_location, OPT_pedantic,
3872                  "ISO C forbids conditional expr with only one void side");
3873       result_type = void_type_node;
3874     }
3875   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3876     {
3877       if (comp_target_types (type1, type2))
3878         result_type = common_pointer_type (type1, type2);
3879       else if (null_pointer_constant_p (orig_op1))
3880         result_type = qualify_type (type2, type1);
3881       else if (null_pointer_constant_p (orig_op2))
3882         result_type = qualify_type (type1, type2);
3883       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3884         {
3885           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3886             pedwarn (input_location, OPT_pedantic,
3887                      "ISO C forbids conditional expr between "
3888                      "%<void *%> and function pointer");
3889           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3890                                                           TREE_TYPE (type2)));
3891         }
3892       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3893         {
3894           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3895             pedwarn (input_location, OPT_pedantic,
3896                      "ISO C forbids conditional expr between "
3897                      "%<void *%> and function pointer");
3898           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3899                                                           TREE_TYPE (type1)));
3900         }
3901       else
3902         {
3903           if (!objc_ok)
3904             pedwarn (input_location, 0,
3905                      "pointer type mismatch in conditional expression");
3906           result_type = build_pointer_type (void_type_node);
3907         }
3908     }
3909   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3910     {
3911       if (!null_pointer_constant_p (orig_op2))
3912         pedwarn (input_location, 0,
3913                  "pointer/integer type mismatch in conditional expression");
3914       else
3915         {
3916           op2 = null_pointer_node;
3917         }
3918       result_type = type1;
3919     }
3920   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3921     {
3922       if (!null_pointer_constant_p (orig_op1))
3923         pedwarn (input_location, 0,
3924                  "pointer/integer type mismatch in conditional expression");
3925       else
3926         {
3927           op1 = null_pointer_node;
3928         }
3929       result_type = type2;
3930     }
3931
3932   if (!result_type)
3933     {
3934       if (flag_cond_mismatch)
3935         result_type = void_type_node;
3936       else
3937         {
3938           error ("type mismatch in conditional expression");
3939           return error_mark_node;
3940         }
3941     }
3942
3943   /* Merge const and volatile flags of the incoming types.  */
3944   result_type
3945     = build_type_variant (result_type,
3946                           TREE_READONLY (op1) || TREE_READONLY (op2),
3947                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3948
3949   if (result_type != TREE_TYPE (op1))
3950     op1 = convert_and_check (result_type, op1);
3951   if (result_type != TREE_TYPE (op2))
3952     op2 = convert_and_check (result_type, op2);
3953
3954   if (ifexp_bcp && ifexp == truthvalue_true_node)
3955     {
3956       op2_int_operands = true;
3957       op1 = c_fully_fold (op1, require_constant_value, NULL);
3958     }
3959   if (ifexp_bcp && ifexp == truthvalue_false_node)
3960     {
3961       op1_int_operands = true;
3962       op2 = c_fully_fold (op2, require_constant_value, NULL);
3963     }
3964   int_const = int_operands = (ifexp_int_operands
3965                               && op1_int_operands
3966                               && op2_int_operands);
3967   if (int_operands)
3968     {
3969       int_const = ((ifexp == truthvalue_true_node
3970                     && TREE_CODE (orig_op1) == INTEGER_CST
3971                     && !TREE_OVERFLOW (orig_op1))
3972                    || (ifexp == truthvalue_false_node
3973                        && TREE_CODE (orig_op2) == INTEGER_CST
3974                        && !TREE_OVERFLOW (orig_op2)));
3975     }
3976   if (int_const || (ifexp_bcp && TREE_CODE (ifexp) == INTEGER_CST))
3977     ret = fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3978   else
3979     {
3980       ret = build3 (COND_EXPR, result_type, ifexp, op1, op2);
3981       if (int_operands)
3982         ret = note_integer_operands (ret);
3983     }
3984   if (ep_result_type)
3985     ret = build1 (EXCESS_PRECISION_EXPR, ep_result_type, ret);
3986
3987   return ret;
3988 }
3989 \f
3990 /* Return a compound expression that performs two expressions and
3991    returns the value of the second of them.  */
3992
3993 tree
3994 build_compound_expr (tree expr1, tree expr2)
3995 {
3996   bool expr1_int_operands, expr2_int_operands;
3997   tree eptype = NULL_TREE;
3998   tree ret;
3999
4000   expr1_int_operands = EXPR_INT_CONST_OPERANDS (expr1);
4001   if (expr1_int_operands)
4002     expr1 = remove_c_maybe_const_expr (expr1);
4003   expr2_int_operands = EXPR_INT_CONST_OPERANDS (expr2);
4004   if (expr2_int_operands)
4005     expr2 = remove_c_maybe_const_expr (expr2);
4006
4007   if (TREE_CODE (expr1) == EXCESS_PRECISION_EXPR)
4008     expr1 = TREE_OPERAND (expr1, 0);
4009   if (TREE_CODE (expr2) == EXCESS_PRECISION_EXPR)
4010     {
4011       eptype = TREE_TYPE (expr2);
4012       expr2 = TREE_OPERAND (expr2, 0);
4013     }
4014
4015   if (!TREE_SIDE_EFFECTS (expr1))
4016     {
4017       /* The left-hand operand of a comma expression is like an expression
4018          statement: with -Wunused, we should warn if it doesn't have
4019          any side-effects, unless it was explicitly cast to (void).  */
4020       if (warn_unused_value)
4021         {
4022           if (VOID_TYPE_P (TREE_TYPE (expr1))
4023               && CONVERT_EXPR_P (expr1))
4024             ; /* (void) a, b */
4025           else if (VOID_TYPE_P (TREE_TYPE (expr1))
4026                    && TREE_CODE (expr1) == COMPOUND_EXPR
4027                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
4028             ; /* (void) a, (void) b, c */
4029           else
4030             warning (OPT_Wunused_value,
4031                      "left-hand operand of comma expression has no effect");
4032         }
4033     }
4034
4035   /* With -Wunused, we should also warn if the left-hand operand does have
4036      side-effects, but computes a value which is not used.  For example, in
4037      `foo() + bar(), baz()' the result of the `+' operator is not used,
4038      so we should issue a warning.  */
4039   else if (warn_unused_value)
4040     warn_if_unused_value (expr1, input_location);
4041
4042   if (expr2 == error_mark_node)
4043     return error_mark_node;
4044
4045   ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
4046
4047   if (flag_isoc99
4048       && expr1_int_operands
4049       && expr2_int_operands)
4050     ret = note_integer_operands (ret);
4051
4052   if (eptype)
4053     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
4054
4055   return ret;
4056 }
4057
4058 /* Issue -Wcast-qual warnings when appropriate.  TYPE is the type to
4059    which we are casting.  OTYPE is the type of the expression being
4060    cast.  Both TYPE and OTYPE are pointer types.  -Wcast-qual appeared
4061    on the command line.  */
4062
4063 static void
4064 handle_warn_cast_qual (tree type, tree otype)
4065 {
4066   tree in_type = type;
4067   tree in_otype = otype;
4068   int added = 0;
4069   int discarded = 0;
4070   bool is_const;
4071
4072   /* Check that the qualifiers on IN_TYPE are a superset of the
4073      qualifiers of IN_OTYPE.  The outermost level of POINTER_TYPE
4074      nodes is uninteresting and we stop as soon as we hit a
4075      non-POINTER_TYPE node on either type.  */
4076   do
4077     {
4078       in_otype = TREE_TYPE (in_otype);
4079       in_type = TREE_TYPE (in_type);
4080
4081       /* GNU C allows cv-qualified function types.  'const' means the
4082          function is very pure, 'volatile' means it can't return.  We
4083          need to warn when such qualifiers are added, not when they're
4084          taken away.  */
4085       if (TREE_CODE (in_otype) == FUNCTION_TYPE
4086           && TREE_CODE (in_type) == FUNCTION_TYPE)
4087         added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
4088       else
4089         discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
4090     }
4091   while (TREE_CODE (in_type) == POINTER_TYPE
4092          && TREE_CODE (in_otype) == POINTER_TYPE);
4093
4094   if (added)
4095     warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
4096
4097   if (discarded)
4098     /* There are qualifiers present in IN_OTYPE that are not present
4099        in IN_TYPE.  */
4100     warning (OPT_Wcast_qual,
4101              "cast discards qualifiers from pointer target type");
4102
4103   if (added || discarded)
4104     return;
4105
4106   /* A cast from **T to const **T is unsafe, because it can cause a
4107      const value to be changed with no additional warning.  We only
4108      issue this warning if T is the same on both sides, and we only
4109      issue the warning if there are the same number of pointers on
4110      both sides, as otherwise the cast is clearly unsafe anyhow.  A
4111      cast is unsafe when a qualifier is added at one level and const
4112      is not present at all outer levels.
4113
4114      To issue this warning, we check at each level whether the cast
4115      adds new qualifiers not already seen.  We don't need to special
4116      case function types, as they won't have the same
4117      TYPE_MAIN_VARIANT.  */
4118
4119   if (TYPE_MAIN_VARIANT (in_type) != TYPE_MAIN_VARIANT (in_otype))
4120     return;
4121   if (TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE)
4122     return;
4123
4124   in_type = type;
4125   in_otype = otype;
4126   is_const = TYPE_READONLY (TREE_TYPE (in_type));
4127   do
4128     {
4129       in_type = TREE_TYPE (in_type);
4130       in_otype = TREE_TYPE (in_otype);
4131       if ((TYPE_QUALS (in_type) &~ TYPE_QUALS (in_otype)) != 0
4132           && !is_const)
4133         {
4134           warning (OPT_Wcast_qual,
4135                    ("new qualifiers in middle of multi-level non-const cast "
4136                     "are unsafe"));
4137           break;
4138         }
4139       if (is_const)
4140         is_const = TYPE_READONLY (in_type);
4141     }
4142   while (TREE_CODE (in_type) == POINTER_TYPE);
4143 }
4144
4145 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
4146
4147 tree
4148 build_c_cast (tree type, tree expr)
4149 {
4150   tree value;
4151
4152   if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
4153     expr = TREE_OPERAND (expr, 0);
4154
4155   value = expr;
4156
4157   if (type == error_mark_node || expr == error_mark_node)
4158     return error_mark_node;
4159
4160   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
4161      only in <protocol> qualifications.  But when constructing cast expressions,
4162      the protocols do matter and must be kept around.  */
4163   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
4164     return build1 (NOP_EXPR, type, expr);
4165
4166   type = TYPE_MAIN_VARIANT (type);
4167
4168   if (TREE_CODE (type) == ARRAY_TYPE)
4169     {
4170       error ("cast specifies array type");
4171       return error_mark_node;
4172     }
4173
4174   if (TREE_CODE (type) == FUNCTION_TYPE)
4175     {
4176       error ("cast specifies function type");
4177       return error_mark_node;
4178     }
4179
4180   if (!VOID_TYPE_P (type))
4181     {
4182       value = require_complete_type (value);
4183       if (value == error_mark_node)
4184         return error_mark_node;
4185     }
4186
4187   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
4188     {
4189       if (TREE_CODE (type) == RECORD_TYPE
4190           || TREE_CODE (type) == UNION_TYPE)
4191         pedwarn (input_location, OPT_pedantic,
4192                  "ISO C forbids casting nonscalar to the same type");
4193     }
4194   else if (TREE_CODE (type) == UNION_TYPE)
4195     {
4196       tree field;
4197
4198       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4199         if (TREE_TYPE (field) != error_mark_node
4200             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
4201                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
4202           break;
4203
4204       if (field)
4205         {
4206           tree t;
4207
4208           pedwarn (input_location, OPT_pedantic,
4209                    "ISO C forbids casts to union type");
4210           t = digest_init (type,
4211                            build_constructor_single (type, field, value),
4212                            NULL_TREE, false, true, 0);
4213           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4214           return t;
4215         }
4216       error ("cast to union type from type not present in union");
4217       return error_mark_node;
4218     }
4219   else
4220     {
4221       tree otype, ovalue;
4222
4223       if (type == void_type_node)
4224         return build1 (CONVERT_EXPR, type, value);
4225
4226       otype = TREE_TYPE (value);
4227
4228       /* Optionally warn about potentially worrisome casts.  */
4229       if (warn_cast_qual
4230           && TREE_CODE (type) == POINTER_TYPE
4231           && TREE_CODE (otype) == POINTER_TYPE)
4232         handle_warn_cast_qual (type, otype);
4233
4234       /* Warn about possible alignment problems.  */
4235       if (STRICT_ALIGNMENT
4236           && TREE_CODE (type) == POINTER_TYPE
4237           && TREE_CODE (otype) == POINTER_TYPE
4238           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4239           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4240           /* Don't warn about opaque types, where the actual alignment
4241              restriction is unknown.  */
4242           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4243                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4244                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4245           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4246         warning (OPT_Wcast_align,
4247                  "cast increases required alignment of target type");
4248
4249       if (TREE_CODE (type) == INTEGER_TYPE
4250           && TREE_CODE (otype) == POINTER_TYPE
4251           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4252       /* Unlike conversion of integers to pointers, where the
4253          warning is disabled for converting constants because
4254          of cases such as SIG_*, warn about converting constant
4255          pointers to integers. In some cases it may cause unwanted
4256          sign extension, and a warning is appropriate.  */
4257         warning (OPT_Wpointer_to_int_cast,
4258                  "cast from pointer to integer of different size");
4259
4260       if (TREE_CODE (value) == CALL_EXPR
4261           && TREE_CODE (type) != TREE_CODE (otype))
4262         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
4263                  "to non-matching type %qT", otype, type);
4264
4265       if (TREE_CODE (type) == POINTER_TYPE
4266           && TREE_CODE (otype) == INTEGER_TYPE
4267           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4268           /* Don't warn about converting any constant.  */
4269           && !TREE_CONSTANT (value))
4270         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4271                  "of different size");
4272
4273       if (warn_strict_aliasing <= 2)
4274         strict_aliasing_warning (otype, type, expr);
4275
4276       /* If pedantic, warn for conversions between function and object
4277          pointer types, except for converting a null pointer constant
4278          to function pointer type.  */
4279       if (pedantic
4280           && TREE_CODE (type) == POINTER_TYPE
4281           && TREE_CODE (otype) == POINTER_TYPE
4282           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4283           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4284         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
4285                  "conversion of function pointer to object pointer type");
4286
4287       if (pedantic
4288           && TREE_CODE (type) == POINTER_TYPE
4289           && TREE_CODE (otype) == POINTER_TYPE
4290           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4291           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4292           && !null_pointer_constant_p (value))
4293         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
4294                  "conversion of object pointer to function pointer type");
4295
4296       ovalue = value;
4297       value = convert (type, value);
4298
4299       /* Ignore any integer overflow caused by the cast.  */
4300       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4301         {
4302           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4303             {
4304               if (!TREE_OVERFLOW (value))
4305                 {
4306                   /* Avoid clobbering a shared constant.  */
4307                   value = copy_node (value);
4308                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4309                 }
4310             }
4311           else if (TREE_OVERFLOW (value))
4312             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4313             value = build_int_cst_wide (TREE_TYPE (value),
4314                                         TREE_INT_CST_LOW (value),
4315                                         TREE_INT_CST_HIGH (value));
4316         }
4317     }
4318
4319   /* Don't let a cast be an lvalue.  */
4320   if (value == expr)
4321     value = non_lvalue (value);
4322
4323   /* Don't allow the results of casting to floating-point or complex
4324      types be confused with actual constants, or casts involving
4325      integer and pointer types other than direct integer-to-integer
4326      and integer-to-pointer be confused with integer constant
4327      expressions and null pointer constants.  */
4328   if (TREE_CODE (value) == REAL_CST
4329       || TREE_CODE (value) == COMPLEX_CST
4330       || (TREE_CODE (value) == INTEGER_CST
4331           && !((TREE_CODE (expr) == INTEGER_CST
4332                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4333                || TREE_CODE (expr) == REAL_CST
4334                || TREE_CODE (expr) == COMPLEX_CST)))
4335       value = build1 (NOP_EXPR, type, value);
4336
4337   return value;
4338 }
4339
4340 /* Interpret a cast of expression EXPR to type TYPE.  */
4341 tree
4342 c_cast_expr (struct c_type_name *type_name, tree expr, location_t loc)
4343 {
4344   tree type;
4345   tree type_expr = NULL_TREE;
4346   bool type_expr_const = true;
4347   tree ret;
4348   int saved_wsp = warn_strict_prototypes;
4349
4350   /* This avoids warnings about unprototyped casts on
4351      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4352   if (TREE_CODE (expr) == INTEGER_CST)
4353     warn_strict_prototypes = 0;
4354   type = groktypename (type_name, &type_expr, &type_expr_const);
4355   warn_strict_prototypes = saved_wsp;
4356
4357   ret = build_c_cast (type, expr);
4358   if (type_expr)
4359     {
4360       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4361       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4362     }
4363
4364   if (CAN_HAVE_LOCATION_P (ret) && !EXPR_HAS_LOCATION (ret))
4365     SET_EXPR_LOCATION (ret, loc);
4366
4367   /* C++ does not permits types to be defined in a cast.  */
4368   if (warn_cxx_compat && type_name->specs->tag_defined_p)
4369     warning_at (loc, OPT_Wc___compat,
4370                 "defining a type in a cast is invalid in C++");
4371
4372   return ret;
4373 }
4374 \f
4375 /* Build an assignment expression of lvalue LHS from value RHS.
4376    If LHS_ORIGTYPE is not NULL, it is the original type of LHS, which
4377    may differ from TREE_TYPE (LHS) for an enum bitfield.
4378    MODIFYCODE is the code for a binary operator that we use
4379    to combine the old value of LHS with RHS to get the new value.
4380    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4381    If RHS_ORIGTYPE is not NULL_TREE, it is the original type of RHS,
4382    which may differ from TREE_TYPE (RHS) for an enum value.
4383
4384    LOCATION is the location of the MODIFYCODE operator.  */
4385
4386 tree
4387 build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
4388                    enum tree_code modifycode, tree rhs, tree rhs_origtype)
4389 {
4390   tree result;
4391   tree newrhs;
4392   tree rhs_semantic_type = NULL_TREE;
4393   tree lhstype = TREE_TYPE (lhs);
4394   tree olhstype = lhstype;
4395   bool npc;
4396
4397   /* Types that aren't fully specified cannot be used in assignments.  */
4398   lhs = require_complete_type (lhs);
4399
4400   /* Avoid duplicate error messages from operands that had errors.  */
4401   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4402     return error_mark_node;
4403
4404   if (!lvalue_or_else (lhs, lv_assign))
4405     return error_mark_node;
4406
4407   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4408     {
4409       rhs_semantic_type = TREE_TYPE (rhs);
4410       rhs = TREE_OPERAND (rhs, 0);
4411     }
4412
4413   newrhs = rhs;
4414
4415   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4416     {
4417       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4418                                       lhs_origtype, modifycode, rhs,
4419                                       rhs_origtype);
4420       if (inner == error_mark_node)
4421         return error_mark_node;
4422       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4423                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4424       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4425       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4426       protected_set_expr_location (result, location);
4427       return result;
4428     }
4429
4430   /* If a binary op has been requested, combine the old LHS value with the RHS
4431      producing the value we should actually store into the LHS.  */
4432
4433   if (modifycode != NOP_EXPR)
4434     {
4435       lhs = c_fully_fold (lhs, false, NULL);
4436       lhs = stabilize_reference (lhs);
4437       newrhs = build_binary_op (location,
4438                                 modifycode, lhs, rhs, 1);
4439
4440       /* The original type of the right hand side is no longer
4441          meaningful.  */
4442       rhs_origtype = NULL_TREE;
4443     }
4444
4445   /* Give an error for storing in something that is 'const'.  */
4446
4447   if (TYPE_READONLY (lhstype)
4448       || ((TREE_CODE (lhstype) == RECORD_TYPE
4449            || TREE_CODE (lhstype) == UNION_TYPE)
4450           && C_TYPE_FIELDS_READONLY (lhstype)))
4451     {
4452       readonly_error (lhs, lv_assign);
4453       return error_mark_node;
4454     }
4455   else if (TREE_READONLY (lhs))
4456     readonly_warning (lhs, lv_assign);
4457
4458   /* If storing into a structure or union member,
4459      it has probably been given type `int'.
4460      Compute the type that would go with
4461      the actual amount of storage the member occupies.  */
4462
4463   if (TREE_CODE (lhs) == COMPONENT_REF
4464       && (TREE_CODE (lhstype) == INTEGER_TYPE
4465           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4466           || TREE_CODE (lhstype) == REAL_TYPE
4467           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4468     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4469
4470   /* If storing in a field that is in actuality a short or narrower than one,
4471      we must store in the field in its actual type.  */
4472
4473   if (lhstype != TREE_TYPE (lhs))
4474     {
4475       lhs = copy_node (lhs);
4476       TREE_TYPE (lhs) = lhstype;
4477     }
4478
4479   /* Issue -Wc++-compat warnings about an assignment to an enum type
4480      when LHS does not have its original type.  This happens for,
4481      e.g., an enum bitfield in a struct.  */
4482   if (warn_cxx_compat
4483       && lhs_origtype != NULL_TREE
4484       && lhs_origtype != lhstype
4485       && TREE_CODE (lhs_origtype) == ENUMERAL_TYPE)
4486     {
4487       tree checktype = (rhs_origtype != NULL_TREE
4488                         ? rhs_origtype
4489                         : TREE_TYPE (rhs));
4490       if (checktype != error_mark_node
4491           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (lhs_origtype))
4492         warning_at (location, OPT_Wc___compat,
4493                     "enum conversion in assignment is invalid in C++");
4494     }
4495
4496   /* Convert new value to destination type.  Fold it first, then
4497      restore any excess precision information, for the sake of
4498      conversion warnings.  */
4499
4500   npc = null_pointer_constant_p (newrhs);
4501   newrhs = c_fully_fold (newrhs, false, NULL);
4502   if (rhs_semantic_type)
4503     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4504   newrhs = convert_for_assignment (lhstype, newrhs, rhs_origtype, ic_assign,
4505                                    npc, NULL_TREE, NULL_TREE, 0);
4506   if (TREE_CODE (newrhs) == ERROR_MARK)
4507     return error_mark_node;
4508
4509   /* Emit ObjC write barrier, if necessary.  */
4510   if (c_dialect_objc () && flag_objc_gc)
4511     {
4512       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4513       if (result)
4514         {
4515           protected_set_expr_location (result, location);
4516           return result;
4517         }
4518     }
4519
4520   /* Scan operands.  */
4521
4522   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4523   TREE_SIDE_EFFECTS (result) = 1;
4524   protected_set_expr_location (result, location);
4525
4526   /* If we got the LHS in a different type for storing in,
4527      convert the result back to the nominal type of LHS
4528      so that the value we return always has the same type
4529      as the LHS argument.  */
4530
4531   if (olhstype == TREE_TYPE (result))
4532     return result;
4533
4534   result = convert_for_assignment (olhstype, result, rhs_origtype, ic_assign,
4535                                    false, NULL_TREE, NULL_TREE, 0);
4536   protected_set_expr_location (result, location);
4537   return result;
4538 }
4539 \f
4540 /* Convert value RHS to type TYPE as preparation for an assignment to
4541    an lvalue of type TYPE.  If ORIGTYPE is not NULL_TREE, it is the
4542    original type of RHS; this differs from TREE_TYPE (RHS) for enum
4543    types.  NULL_POINTER_CONSTANT says whether RHS was a null pointer
4544    constant before any folding.
4545    The real work of conversion is done by `convert'.
4546    The purpose of this function is to generate error messages
4547    for assignments that are not allowed in C.
4548    ERRTYPE says whether it is argument passing, assignment,
4549    initialization or return.
4550
4551    FUNCTION is a tree for the function being called.
4552    PARMNUM is the number of the argument, for printing in error messages.  */
4553
4554 static tree
4555 convert_for_assignment (tree type, tree rhs, tree origtype,
4556                         enum impl_conv errtype, bool null_pointer_constant,
4557                         tree fundecl, tree function, int parmnum)
4558 {
4559   enum tree_code codel = TREE_CODE (type);
4560   tree orig_rhs = rhs;
4561   tree rhstype;
4562   enum tree_code coder;
4563   tree rname = NULL_TREE;
4564   bool objc_ok = false;
4565
4566   if (errtype == ic_argpass)
4567     {
4568       tree selector;
4569       /* Change pointer to function to the function itself for
4570          diagnostics.  */
4571       if (TREE_CODE (function) == ADDR_EXPR
4572           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
4573         function = TREE_OPERAND (function, 0);
4574
4575       /* Handle an ObjC selector specially for diagnostics.  */
4576       selector = objc_message_selector ();
4577       rname = function;
4578       if (selector && parmnum > 2)
4579         {
4580           rname = selector;
4581           parmnum -= 2;
4582         }
4583     }
4584
4585   /* This macro is used to emit diagnostics to ensure that all format
4586      strings are complete sentences, visible to gettext and checked at
4587      compile time.  */
4588 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4589   do {                                                                   \
4590     switch (errtype)                                                     \
4591       {                                                                  \
4592       case ic_argpass:                                                   \
4593         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4594           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4595                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4596                   "expected %qT but argument is of type %qT",            \
4597                   type, rhstype);                                        \
4598         break;                                                           \
4599       case ic_assign:                                                    \
4600         pedwarn (LOCATION, OPT, AS);                                     \
4601         break;                                                           \
4602       case ic_init:                                                      \
4603         pedwarn (LOCATION, OPT, IN);                                     \
4604         break;                                                           \
4605       case ic_return:                                                    \
4606         pedwarn (LOCATION, OPT, RE);                                     \
4607         break;                                                           \
4608       default:                                                           \
4609         gcc_unreachable ();                                              \
4610       }                                                                  \
4611   } while (0)
4612
4613   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4614     rhs = TREE_OPERAND (rhs, 0);
4615
4616   rhstype = TREE_TYPE (rhs);
4617   coder = TREE_CODE (rhstype);
4618
4619   if (coder == ERROR_MARK)
4620     return error_mark_node;
4621
4622   if (c_dialect_objc ())
4623     {
4624       int parmno;
4625
4626       switch (errtype)
4627         {
4628         case ic_return:
4629           parmno = 0;
4630           break;
4631
4632         case ic_assign:
4633           parmno = -1;
4634           break;
4635
4636         case ic_init:
4637           parmno = -2;
4638           break;
4639
4640         default:
4641           parmno = parmnum;
4642           break;
4643         }
4644
4645       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4646     }
4647
4648   if (warn_cxx_compat)
4649     {
4650       tree checktype = origtype != NULL_TREE ? origtype : rhstype;
4651       if (checktype != error_mark_node
4652           && TREE_CODE (type) == ENUMERAL_TYPE
4653           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (type))
4654         {
4655           WARN_FOR_ASSIGNMENT (input_location, OPT_Wc___compat,
4656                                G_("enum conversion when passing argument "
4657                                   "%d of %qE is invalid in C++"),
4658                                G_("enum conversion in assignment is "
4659                                   "invalid in C++"),
4660                                G_("enum conversion in initialization is "
4661                                   "invalid in C++"),
4662                                G_("enum conversion in return is "
4663                                   "invalid in C++"));
4664         }
4665     }
4666
4667   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4668     return rhs;
4669
4670   if (coder == VOID_TYPE)
4671     {
4672       /* Except for passing an argument to an unprototyped function,
4673          this is a constraint violation.  When passing an argument to
4674          an unprototyped function, it is compile-time undefined;
4675          making it a constraint in that case was rejected in
4676          DR#252.  */
4677       error ("void value not ignored as it ought to be");
4678       return error_mark_node;
4679     }
4680   rhs = require_complete_type (rhs);
4681   if (rhs == error_mark_node)
4682     return error_mark_node;
4683   /* A type converts to a reference to it.
4684      This code doesn't fully support references, it's just for the
4685      special case of va_start and va_copy.  */
4686   if (codel == REFERENCE_TYPE
4687       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4688     {
4689       if (!lvalue_p (rhs))
4690         {
4691           error ("cannot pass rvalue to reference parameter");
4692           return error_mark_node;
4693         }
4694       if (!c_mark_addressable (rhs))
4695         return error_mark_node;
4696       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4697
4698       /* We already know that these two types are compatible, but they
4699          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4700          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4701          likely to be va_list, a typedef to __builtin_va_list, which
4702          is different enough that it will cause problems later.  */
4703       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4704         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4705
4706       rhs = build1 (NOP_EXPR, type, rhs);
4707       return rhs;
4708     }
4709   /* Some types can interconvert without explicit casts.  */
4710   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4711            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4712     return convert (type, rhs);
4713   /* Arithmetic types all interconvert, and enum is treated like int.  */
4714   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4715             || codel == FIXED_POINT_TYPE
4716             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4717             || codel == BOOLEAN_TYPE)
4718            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4719                || coder == FIXED_POINT_TYPE
4720                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4721                || coder == BOOLEAN_TYPE))
4722     {
4723       tree ret;
4724       bool save = in_late_binary_op;
4725       if (codel == BOOLEAN_TYPE)
4726         in_late_binary_op = true;
4727       ret = convert_and_check (type, orig_rhs);
4728       if (codel == BOOLEAN_TYPE)
4729         in_late_binary_op = save;
4730       return ret;
4731     }
4732
4733   /* Aggregates in different TUs might need conversion.  */
4734   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4735       && codel == coder
4736       && comptypes (type, rhstype))
4737     return convert_and_check (type, rhs);
4738
4739   /* Conversion to a transparent union from its member types.
4740      This applies only to function arguments.  */
4741   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4742       && errtype == ic_argpass)
4743     {
4744       tree memb, marginal_memb = NULL_TREE;
4745
4746       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4747         {
4748           tree memb_type = TREE_TYPE (memb);
4749
4750           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4751                          TYPE_MAIN_VARIANT (rhstype)))
4752             break;
4753
4754           if (TREE_CODE (memb_type) != POINTER_TYPE)
4755             continue;
4756
4757           if (coder == POINTER_TYPE)
4758             {
4759               tree ttl = TREE_TYPE (memb_type);
4760               tree ttr = TREE_TYPE (rhstype);
4761
4762               /* Any non-function converts to a [const][volatile] void *
4763                  and vice versa; otherwise, targets must be the same.
4764                  Meanwhile, the lhs target must have all the qualifiers of
4765                  the rhs.  */
4766               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4767                   || comp_target_types (memb_type, rhstype))
4768                 {
4769                   /* If this type won't generate any warnings, use it.  */
4770                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4771                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4772                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4773                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4774                              == TYPE_QUALS (ttr))
4775                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4776                              == TYPE_QUALS (ttl))))
4777                     break;
4778
4779                   /* Keep looking for a better type, but remember this one.  */
4780                   if (!marginal_memb)
4781                     marginal_memb = memb;
4782                 }
4783             }
4784
4785           /* Can convert integer zero to any pointer type.  */
4786           if (null_pointer_constant)
4787             {
4788               rhs = null_pointer_node;
4789               break;
4790             }
4791         }
4792
4793       if (memb || marginal_memb)
4794         {
4795           if (!memb)
4796             {
4797               /* We have only a marginally acceptable member type;
4798                  it needs a warning.  */
4799               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4800               tree ttr = TREE_TYPE (rhstype);
4801
4802               /* Const and volatile mean something different for function
4803                  types, so the usual warnings are not appropriate.  */
4804               if (TREE_CODE (ttr) == FUNCTION_TYPE
4805                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4806                 {
4807                   /* Because const and volatile on functions are
4808                      restrictions that say the function will not do
4809                      certain things, it is okay to use a const or volatile
4810                      function where an ordinary one is wanted, but not
4811                      vice-versa.  */
4812                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4813                     WARN_FOR_ASSIGNMENT (input_location, 0,
4814                                          G_("passing argument %d of %qE "
4815                                             "makes qualified function "
4816                                             "pointer from unqualified"),
4817                                          G_("assignment makes qualified "
4818                                             "function pointer from "
4819                                             "unqualified"),
4820                                          G_("initialization makes qualified "
4821                                             "function pointer from "
4822                                             "unqualified"),
4823                                          G_("return makes qualified function "
4824                                             "pointer from unqualified"));
4825                 }
4826               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4827                 WARN_FOR_ASSIGNMENT (input_location, 0,
4828                                      G_("passing argument %d of %qE discards "
4829                                         "qualifiers from pointer target type"),
4830                                      G_("assignment discards qualifiers "
4831                                         "from pointer target type"),
4832                                      G_("initialization discards qualifiers "
4833                                         "from pointer target type"),
4834                                      G_("return discards qualifiers from "
4835                                         "pointer target type"));
4836
4837               memb = marginal_memb;
4838             }
4839
4840           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4841             pedwarn (input_location, OPT_pedantic,
4842                      "ISO C prohibits argument conversion to union type");
4843
4844           rhs = fold_convert (TREE_TYPE (memb), rhs);
4845           return build_constructor_single (type, memb, rhs);
4846         }
4847     }
4848
4849   /* Conversions among pointers */
4850   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4851            && (coder == codel))
4852     {
4853       tree ttl = TREE_TYPE (type);
4854       tree ttr = TREE_TYPE (rhstype);
4855       tree mvl = ttl;
4856       tree mvr = ttr;
4857       bool is_opaque_pointer;
4858       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4859
4860       if (TREE_CODE (mvl) != ARRAY_TYPE)
4861         mvl = TYPE_MAIN_VARIANT (mvl);
4862       if (TREE_CODE (mvr) != ARRAY_TYPE)
4863         mvr = TYPE_MAIN_VARIANT (mvr);
4864       /* Opaque pointers are treated like void pointers.  */
4865       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4866
4867       /* C++ does not allow the implicit conversion void* -> T*.  However,
4868          for the purpose of reducing the number of false positives, we
4869          tolerate the special case of
4870
4871                 int *p = NULL;
4872
4873          where NULL is typically defined in C to be '(void *) 0'.  */
4874       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4875         warning (OPT_Wc___compat, "request for implicit conversion from "
4876                  "%qT to %qT not permitted in C++", rhstype, type);
4877
4878       /* Check if the right-hand side has a format attribute but the
4879          left-hand side doesn't.  */
4880       if (warn_missing_format_attribute
4881           && check_missing_format_attribute (type, rhstype))
4882         {
4883           switch (errtype)
4884           {
4885           case ic_argpass:
4886             warning (OPT_Wmissing_format_attribute,
4887                      "argument %d of %qE might be "
4888                      "a candidate for a format attribute",
4889                      parmnum, rname);
4890             break;
4891           case ic_assign:
4892             warning (OPT_Wmissing_format_attribute,
4893                      "assignment left-hand side might be "
4894                      "a candidate for a format attribute");
4895             break;
4896           case ic_init:
4897             warning (OPT_Wmissing_format_attribute,
4898                      "initialization left-hand side might be "
4899                      "a candidate for a format attribute");
4900             break;
4901           case ic_return:
4902             warning (OPT_Wmissing_format_attribute,
4903                      "return type might be "
4904                      "a candidate for a format attribute");
4905             break;
4906           default:
4907             gcc_unreachable ();
4908           }
4909         }
4910
4911       /* Any non-function converts to a [const][volatile] void *
4912          and vice versa; otherwise, targets must be the same.
4913          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4914       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4915           || (target_cmp = comp_target_types (type, rhstype))
4916           || is_opaque_pointer
4917           || (c_common_unsigned_type (mvl)
4918               == c_common_unsigned_type (mvr)))
4919         {
4920           if (pedantic
4921               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4922                   ||
4923                   (VOID_TYPE_P (ttr)
4924                    && !null_pointer_constant
4925                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4926             WARN_FOR_ASSIGNMENT (input_location, OPT_pedantic,
4927                                  G_("ISO C forbids passing argument %d of "
4928                                     "%qE between function pointer "
4929                                     "and %<void *%>"),
4930                                  G_("ISO C forbids assignment between "
4931                                     "function pointer and %<void *%>"),
4932                                  G_("ISO C forbids initialization between "
4933                                     "function pointer and %<void *%>"),
4934                                  G_("ISO C forbids return between function "
4935                                     "pointer and %<void *%>"));
4936           /* Const and volatile mean something different for function types,
4937              so the usual warnings are not appropriate.  */
4938           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4939                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4940             {
4941               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4942                 {
4943                   /* Types differing only by the presence of the 'volatile'
4944                      qualifier are acceptable if the 'volatile' has been added
4945                      in by the Objective-C EH machinery.  */
4946                   if (!objc_type_quals_match (ttl, ttr))
4947                     WARN_FOR_ASSIGNMENT (input_location, 0,
4948                                          G_("passing argument %d of %qE discards "
4949                                             "qualifiers from pointer target type"),
4950                                          G_("assignment discards qualifiers "
4951                                             "from pointer target type"),
4952                                          G_("initialization discards qualifiers "
4953                                             "from pointer target type"),
4954                                          G_("return discards qualifiers from "
4955                                             "pointer target type"));
4956                 }
4957               /* If this is not a case of ignoring a mismatch in signedness,
4958                  no warning.  */
4959               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4960                        || target_cmp)
4961                 ;
4962               /* If there is a mismatch, do warn.  */
4963               else if (warn_pointer_sign)
4964                 WARN_FOR_ASSIGNMENT (input_location, OPT_Wpointer_sign,
4965                                      G_("pointer targets in passing argument "
4966                                         "%d of %qE differ in signedness"),
4967                                      G_("pointer targets in assignment "
4968                                         "differ in signedness"),
4969                                      G_("pointer targets in initialization "
4970                                         "differ in signedness"),
4971                                      G_("pointer targets in return differ "
4972                                         "in signedness"));
4973             }
4974           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4975                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4976             {
4977               /* Because const and volatile on functions are restrictions
4978                  that say the function will not do certain things,
4979                  it is okay to use a const or volatile function
4980                  where an ordinary one is wanted, but not vice-versa.  */
4981               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4982                 WARN_FOR_ASSIGNMENT (input_location, 0,
4983                                      G_("passing argument %d of %qE makes "
4984                                         "qualified function pointer "
4985                                         "from unqualified"),
4986                                      G_("assignment makes qualified function "
4987                                         "pointer from unqualified"),
4988                                      G_("initialization makes qualified "
4989                                         "function pointer from unqualified"),
4990                                      G_("return makes qualified function "
4991                                         "pointer from unqualified"));
4992             }
4993         }
4994       else
4995         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4996         if (!objc_ok)
4997           WARN_FOR_ASSIGNMENT (input_location, 0,
4998                                G_("passing argument %d of %qE from "
4999                                   "incompatible pointer type"),
5000                                G_("assignment from incompatible pointer type"),
5001                                G_("initialization from incompatible "
5002                                   "pointer type"),
5003                                G_("return from incompatible pointer type"));
5004
5005       return convert (type, rhs);
5006     }
5007   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
5008     {
5009       /* ??? This should not be an error when inlining calls to
5010          unprototyped functions.  */
5011       error ("invalid use of non-lvalue array");
5012       return error_mark_node;
5013     }
5014   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
5015     {
5016       /* An explicit constant 0 can convert to a pointer,
5017          or one that results from arithmetic, even including
5018          a cast to integer type.  */
5019       if (!null_pointer_constant)
5020         WARN_FOR_ASSIGNMENT (input_location, 0,
5021                              G_("passing argument %d of %qE makes "
5022                                 "pointer from integer without a cast"),
5023                              G_("assignment makes pointer from integer "
5024                                 "without a cast"),
5025                              G_("initialization makes pointer from "
5026                                 "integer without a cast"),
5027                              G_("return makes pointer from integer "
5028                                 "without a cast"));
5029
5030       return convert (type, rhs);
5031     }
5032   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
5033     {
5034       WARN_FOR_ASSIGNMENT (input_location, 0,
5035                            G_("passing argument %d of %qE makes integer "
5036                               "from pointer without a cast"),
5037                            G_("assignment makes integer from pointer "
5038                               "without a cast"),
5039                            G_("initialization makes integer from pointer "
5040                               "without a cast"),
5041                            G_("return makes integer from pointer "
5042                               "without a cast"));
5043       return convert (type, rhs);
5044     }
5045   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
5046     {
5047       tree ret;
5048       bool save = in_late_binary_op;
5049       in_late_binary_op = true;
5050       ret = convert (type, rhs);
5051       in_late_binary_op = save;
5052       return ret;
5053     }
5054
5055   switch (errtype)
5056     {
5057     case ic_argpass:
5058       error ("incompatible type for argument %d of %qE", parmnum, rname);
5059       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
5060               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
5061               "expected %qT but argument is of type %qT", type, rhstype);
5062       break;
5063     case ic_assign:
5064       error ("incompatible types when assigning to type %qT from type %qT",
5065              type, rhstype);
5066       break;
5067     case ic_init:
5068       error ("incompatible types when initializing type %qT using type %qT",
5069              type, rhstype);
5070       break;
5071     case ic_return:
5072       error ("incompatible types when returning type %qT but %qT was expected",
5073              rhstype, type);
5074       break;
5075     default:
5076       gcc_unreachable ();
5077     }
5078
5079   return error_mark_node;
5080 }
5081 \f
5082 /* If VALUE is a compound expr all of whose expressions are constant, then
5083    return its value.  Otherwise, return error_mark_node.
5084
5085    This is for handling COMPOUND_EXPRs as initializer elements
5086    which is allowed with a warning when -pedantic is specified.  */
5087
5088 static tree
5089 valid_compound_expr_initializer (tree value, tree endtype)
5090 {
5091   if (TREE_CODE (value) == COMPOUND_EXPR)
5092     {
5093       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
5094           == error_mark_node)
5095         return error_mark_node;
5096       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
5097                                               endtype);
5098     }
5099   else if (!initializer_constant_valid_p (value, endtype))
5100     return error_mark_node;
5101   else
5102     return value;
5103 }
5104 \f
5105 /* Perform appropriate conversions on the initial value of a variable,
5106    store it in the declaration DECL,
5107    and print any error messages that are appropriate.
5108    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5109    If the init is invalid, store an ERROR_MARK.  */
5110
5111 void
5112 store_init_value (tree decl, tree init, tree origtype)
5113 {
5114   tree value, type;
5115   bool npc = false;
5116
5117   /* If variable's type was invalidly declared, just ignore it.  */
5118
5119   type = TREE_TYPE (decl);
5120   if (TREE_CODE (type) == ERROR_MARK)
5121     return;
5122
5123   /* Digest the specified initializer into an expression.  */
5124
5125   if (init)
5126     npc = null_pointer_constant_p (init);
5127   value = digest_init (type, init, origtype, npc, true, TREE_STATIC (decl));
5128
5129   /* Store the expression if valid; else report error.  */
5130
5131   if (!in_system_header
5132       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
5133     warning (OPT_Wtraditional, "traditional C rejects automatic "
5134              "aggregate initialization");
5135
5136   DECL_INITIAL (decl) = value;
5137
5138   /* ANSI wants warnings about out-of-range constant initializers.  */
5139   STRIP_TYPE_NOPS (value);
5140   if (TREE_STATIC (decl))
5141     constant_expression_warning (value);
5142
5143   /* Check if we need to set array size from compound literal size.  */
5144   if (TREE_CODE (type) == ARRAY_TYPE
5145       && TYPE_DOMAIN (type) == 0
5146       && value != error_mark_node)
5147     {
5148       tree inside_init = init;
5149
5150       STRIP_TYPE_NOPS (inside_init);
5151       inside_init = fold (inside_init);
5152
5153       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5154         {
5155           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5156
5157           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
5158             {
5159               /* For int foo[] = (int [3]){1}; we need to set array size
5160                  now since later on array initializer will be just the
5161                  brace enclosed list of the compound literal.  */
5162               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5163               TREE_TYPE (decl) = type;
5164               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
5165               layout_type (type);
5166               layout_decl (cldecl, 0);
5167             }
5168         }
5169     }
5170 }
5171 \f
5172 /* Methods for storing and printing names for error messages.  */
5173
5174 /* Implement a spelling stack that allows components of a name to be pushed
5175    and popped.  Each element on the stack is this structure.  */
5176
5177 struct spelling
5178 {
5179   int kind;
5180   union
5181     {
5182       unsigned HOST_WIDE_INT i;
5183       const char *s;
5184     } u;
5185 };
5186
5187 #define SPELLING_STRING 1
5188 #define SPELLING_MEMBER 2
5189 #define SPELLING_BOUNDS 3
5190
5191 static struct spelling *spelling;       /* Next stack element (unused).  */
5192 static struct spelling *spelling_base;  /* Spelling stack base.  */
5193 static int spelling_size;               /* Size of the spelling stack.  */
5194
5195 /* Macros to save and restore the spelling stack around push_... functions.
5196    Alternative to SAVE_SPELLING_STACK.  */
5197
5198 #define SPELLING_DEPTH() (spelling - spelling_base)
5199 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
5200
5201 /* Push an element on the spelling stack with type KIND and assign VALUE
5202    to MEMBER.  */
5203
5204 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
5205 {                                                                       \
5206   int depth = SPELLING_DEPTH ();                                        \
5207                                                                         \
5208   if (depth >= spelling_size)                                           \
5209     {                                                                   \
5210       spelling_size += 10;                                              \
5211       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
5212                                   spelling_size);                       \
5213       RESTORE_SPELLING_DEPTH (depth);                                   \
5214     }                                                                   \
5215                                                                         \
5216   spelling->kind = (KIND);                                              \
5217   spelling->MEMBER = (VALUE);                                           \
5218   spelling++;                                                           \
5219 }
5220
5221 /* Push STRING on the stack.  Printed literally.  */
5222
5223 static void
5224 push_string (const char *string)
5225 {
5226   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5227 }
5228
5229 /* Push a member name on the stack.  Printed as '.' STRING.  */
5230
5231 static void
5232 push_member_name (tree decl)
5233 {
5234   const char *const string
5235     = (DECL_NAME (decl)
5236        ? identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)))
5237        : _("<anonymous>"));
5238   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5239 }
5240
5241 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5242
5243 static void
5244 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5245 {
5246   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5247 }
5248
5249 /* Compute the maximum size in bytes of the printed spelling.  */
5250
5251 static int
5252 spelling_length (void)
5253 {
5254   int size = 0;
5255   struct spelling *p;
5256
5257   for (p = spelling_base; p < spelling; p++)
5258     {
5259       if (p->kind == SPELLING_BOUNDS)
5260         size += 25;
5261       else
5262         size += strlen (p->u.s) + 1;
5263     }
5264
5265   return size;
5266 }
5267
5268 /* Print the spelling to BUFFER and return it.  */
5269
5270 static char *
5271 print_spelling (char *buffer)
5272 {
5273   char *d = buffer;
5274   struct spelling *p;
5275
5276   for (p = spelling_base; p < spelling; p++)
5277     if (p->kind == SPELLING_BOUNDS)
5278       {
5279         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5280         d += strlen (d);
5281       }
5282     else
5283       {
5284         const char *s;
5285         if (p->kind == SPELLING_MEMBER)
5286           *d++ = '.';
5287         for (s = p->u.s; (*d = *s++); d++)
5288           ;
5289       }
5290   *d++ = '\0';
5291   return buffer;
5292 }
5293
5294 /* Issue an error message for a bad initializer component.
5295    MSGID identifies the message.
5296    The component name is taken from the spelling stack.  */
5297
5298 void
5299 error_init (const char *msgid)
5300 {
5301   char *ofwhat;
5302
5303   error ("%s", _(msgid));
5304   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5305   if (*ofwhat)
5306     error ("(near initialization for %qs)", ofwhat);
5307 }
5308
5309 /* Issue a pedantic warning for a bad initializer component.  OPT is
5310    the option OPT_* (from options.h) controlling this warning or 0 if
5311    it is unconditionally given.  MSGID identifies the message.  The
5312    component name is taken from the spelling stack.  */
5313
5314 void
5315 pedwarn_init (location_t location, int opt, const char *msgid)
5316 {
5317   char *ofwhat;
5318
5319   pedwarn (location, opt, "%s", _(msgid));
5320   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5321   if (*ofwhat)
5322     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5323 }
5324
5325 /* Issue a warning for a bad initializer component.
5326
5327    OPT is the OPT_W* value corresponding to the warning option that
5328    controls this warning.  MSGID identifies the message.  The
5329    component name is taken from the spelling stack.  */
5330
5331 static void
5332 warning_init (int opt, const char *msgid)
5333 {
5334   char *ofwhat;
5335
5336   warning (opt, "%s", _(msgid));
5337   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5338   if (*ofwhat)
5339     warning (opt, "(near initialization for %qs)", ofwhat);
5340 }
5341 \f
5342 /* If TYPE is an array type and EXPR is a parenthesized string
5343    constant, warn if pedantic that EXPR is being used to initialize an
5344    object of type TYPE.  */
5345
5346 void
5347 maybe_warn_string_init (tree type, struct c_expr expr)
5348 {
5349   if (pedantic
5350       && TREE_CODE (type) == ARRAY_TYPE
5351       && TREE_CODE (expr.value) == STRING_CST
5352       && expr.original_code != STRING_CST)
5353     pedwarn_init (input_location, OPT_pedantic,
5354                   "array initialized from parenthesized string constant");
5355 }
5356
5357 /* Digest the parser output INIT as an initializer for type TYPE.
5358    Return a C expression of type TYPE to represent the initial value.
5359
5360    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5361
5362    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
5363
5364    If INIT is a string constant, STRICT_STRING is true if it is
5365    unparenthesized or we should not warn here for it being parenthesized.
5366    For other types of INIT, STRICT_STRING is not used.
5367
5368    REQUIRE_CONSTANT requests an error if non-constant initializers or
5369    elements are seen.  */
5370
5371 static tree
5372 digest_init (tree type, tree init, tree origtype, bool null_pointer_constant,
5373              bool strict_string, int require_constant)
5374 {
5375   enum tree_code code = TREE_CODE (type);
5376   tree inside_init = init;
5377   tree semantic_type = NULL_TREE;
5378   bool maybe_const = true;
5379
5380   if (type == error_mark_node
5381       || !init
5382       || init == error_mark_node
5383       || TREE_TYPE (init) == error_mark_node)
5384     return error_mark_node;
5385
5386   STRIP_TYPE_NOPS (inside_init);
5387
5388   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
5389     {
5390       semantic_type = TREE_TYPE (inside_init);
5391       inside_init = TREE_OPERAND (inside_init, 0);
5392     }
5393   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
5394   inside_init = decl_constant_value_for_optimization (inside_init);
5395
5396   /* Initialization of an array of chars from a string constant
5397      optionally enclosed in braces.  */
5398
5399   if (code == ARRAY_TYPE && inside_init
5400       && TREE_CODE (inside_init) == STRING_CST)
5401     {
5402       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5403       /* Note that an array could be both an array of character type
5404          and an array of wchar_t if wchar_t is signed char or unsigned
5405          char.  */
5406       bool char_array = (typ1 == char_type_node
5407                          || typ1 == signed_char_type_node
5408                          || typ1 == unsigned_char_type_node);
5409       bool wchar_array = !!comptypes (typ1, wchar_type_node);
5410       bool char16_array = !!comptypes (typ1, char16_type_node);
5411       bool char32_array = !!comptypes (typ1, char32_type_node);
5412
5413       if (char_array || wchar_array || char16_array || char32_array)
5414         {
5415           struct c_expr expr;
5416           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
5417           expr.value = inside_init;
5418           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
5419           expr.original_type = NULL;
5420           maybe_warn_string_init (type, expr);
5421
5422           if (TYPE_DOMAIN (type) && !TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
5423             pedwarn_init (input_location, OPT_pedantic,
5424                           "initialization of a flexible array member");
5425
5426           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5427                          TYPE_MAIN_VARIANT (type)))
5428             return inside_init;
5429
5430           if (char_array)
5431             {
5432               if (typ2 != char_type_node)
5433                 {
5434                   error_init ("char-array initialized from wide string");
5435                   return error_mark_node;
5436                 }
5437             }
5438           else
5439             {
5440               if (typ2 == char_type_node)
5441                 {
5442                   error_init ("wide character array initialized from non-wide "
5443                               "string");
5444                   return error_mark_node;
5445                 }
5446               else if (!comptypes(typ1, typ2))
5447                 {
5448                   error_init ("wide character array initialized from "
5449                               "incompatible wide string");
5450                   return error_mark_node;
5451                 }
5452             }
5453
5454           TREE_TYPE (inside_init) = type;
5455           if (TYPE_DOMAIN (type) != 0
5456               && TYPE_SIZE (type) != 0
5457               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
5458               /* Subtract the size of a single (possibly wide) character
5459                  because it's ok to ignore the terminating null char
5460                  that is counted in the length of the constant.  */
5461               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
5462                                        TREE_STRING_LENGTH (inside_init)
5463                                        - (TYPE_PRECISION (typ1)
5464                                           / BITS_PER_UNIT)))
5465             pedwarn_init (input_location, 0,
5466                           "initializer-string for array of chars is too long");
5467
5468           return inside_init;
5469         }
5470       else if (INTEGRAL_TYPE_P (typ1))
5471         {
5472           error_init ("array of inappropriate type initialized "
5473                       "from string constant");
5474           return error_mark_node;
5475         }
5476     }
5477
5478   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
5479      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
5480      below and handle as a constructor.  */
5481   if (code == VECTOR_TYPE
5482       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
5483       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
5484       && TREE_CONSTANT (inside_init))
5485     {
5486       if (TREE_CODE (inside_init) == VECTOR_CST
5487           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5488                         TYPE_MAIN_VARIANT (type)))
5489         return inside_init;
5490
5491       if (TREE_CODE (inside_init) == CONSTRUCTOR)
5492         {
5493           unsigned HOST_WIDE_INT ix;
5494           tree value;
5495           bool constant_p = true;
5496
5497           /* Iterate through elements and check if all constructor
5498              elements are *_CSTs.  */
5499           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
5500             if (!CONSTANT_CLASS_P (value))
5501               {
5502                 constant_p = false;
5503                 break;
5504               }
5505
5506           if (constant_p)
5507             return build_vector_from_ctor (type,
5508                                            CONSTRUCTOR_ELTS (inside_init));
5509         }
5510     }
5511
5512   if (warn_sequence_point)
5513     verify_sequence_points (inside_init);
5514
5515   /* Any type can be initialized
5516      from an expression of the same type, optionally with braces.  */
5517
5518   if (inside_init && TREE_TYPE (inside_init) != 0
5519       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5520                      TYPE_MAIN_VARIANT (type))
5521           || (code == ARRAY_TYPE
5522               && comptypes (TREE_TYPE (inside_init), type))
5523           || (code == VECTOR_TYPE
5524               && comptypes (TREE_TYPE (inside_init), type))
5525           || (code == POINTER_TYPE
5526               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
5527               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
5528                             TREE_TYPE (type)))))
5529     {
5530       if (code == POINTER_TYPE)
5531         {
5532           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
5533             {
5534               if (TREE_CODE (inside_init) == STRING_CST
5535                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5536                 inside_init = array_to_pointer_conversion (inside_init);
5537               else
5538                 {
5539                   error_init ("invalid use of non-lvalue array");
5540                   return error_mark_node;
5541                 }
5542             }
5543         }
5544
5545       if (code == VECTOR_TYPE)
5546         /* Although the types are compatible, we may require a
5547            conversion.  */
5548         inside_init = convert (type, inside_init);
5549
5550       if (require_constant
5551           && (code == VECTOR_TYPE || !flag_isoc99)
5552           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5553         {
5554           /* As an extension, allow initializing objects with static storage
5555              duration with compound literals (which are then treated just as
5556              the brace enclosed list they contain).  Also allow this for
5557              vectors, as we can only assign them with compound literals.  */
5558           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5559           inside_init = DECL_INITIAL (decl);
5560         }
5561
5562       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
5563           && TREE_CODE (inside_init) != CONSTRUCTOR)
5564         {
5565           error_init ("array initialized from non-constant array expression");
5566           return error_mark_node;
5567         }
5568
5569       /* Compound expressions can only occur here if -pedantic or
5570          -pedantic-errors is specified.  In the later case, we always want
5571          an error.  In the former case, we simply want a warning.  */
5572       if (require_constant && pedantic
5573           && TREE_CODE (inside_init) == COMPOUND_EXPR)
5574         {
5575           inside_init
5576             = valid_compound_expr_initializer (inside_init,
5577                                                TREE_TYPE (inside_init));
5578           if (inside_init == error_mark_node)
5579             error_init ("initializer element is not constant");
5580           else
5581             pedwarn_init (input_location, OPT_pedantic,
5582                           "initializer element is not constant");
5583           if (flag_pedantic_errors)
5584             inside_init = error_mark_node;
5585         }
5586       else if (require_constant
5587                && !initializer_constant_valid_p (inside_init,
5588                                                  TREE_TYPE (inside_init)))
5589         {
5590           error_init ("initializer element is not constant");
5591           inside_init = error_mark_node;
5592         }
5593       else if (require_constant && !maybe_const)
5594         pedwarn_init (input_location, 0,
5595                       "initializer element is not a constant expression");
5596
5597       /* Added to enable additional -Wmissing-format-attribute warnings.  */
5598       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
5599         inside_init = convert_for_assignment (type, inside_init, origtype,
5600                                               ic_init, null_pointer_constant,
5601                                               NULL_TREE, NULL_TREE, 0);
5602       return inside_init;
5603     }
5604
5605   /* Handle scalar types, including conversions.  */
5606
5607   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
5608       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
5609       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
5610     {
5611       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
5612           && (TREE_CODE (init) == STRING_CST
5613               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
5614         inside_init = init = array_to_pointer_conversion (init);
5615       if (semantic_type)
5616         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
5617                               inside_init);
5618       inside_init
5619         = convert_for_assignment (type, inside_init, origtype, ic_init,
5620                                   null_pointer_constant,
5621                                   NULL_TREE, NULL_TREE, 0);
5622
5623       /* Check to see if we have already given an error message.  */
5624       if (inside_init == error_mark_node)
5625         ;
5626       else if (require_constant && !TREE_CONSTANT (inside_init))
5627         {
5628           error_init ("initializer element is not constant");
5629           inside_init = error_mark_node;
5630         }
5631       else if (require_constant
5632                && !initializer_constant_valid_p (inside_init,
5633                                                  TREE_TYPE (inside_init)))
5634         {
5635           error_init ("initializer element is not computable at load time");
5636           inside_init = error_mark_node;
5637         }
5638       else if (require_constant && !maybe_const)
5639         pedwarn_init (input_location, 0,
5640                       "initializer element is not a constant expression");
5641
5642       return inside_init;
5643     }
5644
5645   /* Come here only for records and arrays.  */
5646
5647   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5648     {
5649       error_init ("variable-sized object may not be initialized");
5650       return error_mark_node;
5651     }
5652
5653   error_init ("invalid initializer");
5654   return error_mark_node;
5655 }
5656 \f
5657 /* Handle initializers that use braces.  */
5658
5659 /* Type of object we are accumulating a constructor for.
5660    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5661 static tree constructor_type;
5662
5663 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
5664    left to fill.  */
5665 static tree constructor_fields;
5666
5667 /* For an ARRAY_TYPE, this is the specified index
5668    at which to store the next element we get.  */
5669 static tree constructor_index;
5670
5671 /* For an ARRAY_TYPE, this is the maximum index.  */
5672 static tree constructor_max_index;
5673
5674 /* For a RECORD_TYPE, this is the first field not yet written out.  */
5675 static tree constructor_unfilled_fields;
5676
5677 /* For an ARRAY_TYPE, this is the index of the first element
5678    not yet written out.  */
5679 static tree constructor_unfilled_index;
5680
5681 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5682    This is so we can generate gaps between fields, when appropriate.  */
5683 static tree constructor_bit_index;
5684
5685 /* If we are saving up the elements rather than allocating them,
5686    this is the list of elements so far (in reverse order,
5687    most recent first).  */
5688 static VEC(constructor_elt,gc) *constructor_elements;
5689
5690 /* 1 if constructor should be incrementally stored into a constructor chain,
5691    0 if all the elements should be kept in AVL tree.  */
5692 static int constructor_incremental;
5693
5694 /* 1 if so far this constructor's elements are all compile-time constants.  */
5695 static int constructor_constant;
5696
5697 /* 1 if so far this constructor's elements are all valid address constants.  */
5698 static int constructor_simple;
5699
5700 /* 1 if this constructor has an element that cannot be part of a
5701    constant expression.  */
5702 static int constructor_nonconst;
5703
5704 /* 1 if this constructor is erroneous so far.  */
5705 static int constructor_erroneous;
5706
5707 /* Structure for managing pending initializer elements, organized as an
5708    AVL tree.  */
5709
5710 struct init_node
5711 {
5712   struct init_node *left, *right;
5713   struct init_node *parent;
5714   int balance;
5715   tree purpose;
5716   tree value;
5717   tree origtype;
5718 };
5719
5720 /* Tree of pending elements at this constructor level.
5721    These are elements encountered out of order
5722    which belong at places we haven't reached yet in actually
5723    writing the output.
5724    Will never hold tree nodes across GC runs.  */
5725 static struct init_node *constructor_pending_elts;
5726
5727 /* The SPELLING_DEPTH of this constructor.  */
5728 static int constructor_depth;
5729
5730 /* DECL node for which an initializer is being read.
5731    0 means we are reading a constructor expression
5732    such as (struct foo) {...}.  */
5733 static tree constructor_decl;
5734
5735 /* Nonzero if this is an initializer for a top-level decl.  */
5736 static int constructor_top_level;
5737
5738 /* Nonzero if there were any member designators in this initializer.  */
5739 static int constructor_designated;
5740
5741 /* Nesting depth of designator list.  */
5742 static int designator_depth;
5743
5744 /* Nonzero if there were diagnosed errors in this designator list.  */
5745 static int designator_erroneous;
5746
5747 \f
5748 /* This stack has a level for each implicit or explicit level of
5749    structuring in the initializer, including the outermost one.  It
5750    saves the values of most of the variables above.  */
5751
5752 struct constructor_range_stack;
5753
5754 struct constructor_stack
5755 {
5756   struct constructor_stack *next;
5757   tree type;
5758   tree fields;
5759   tree index;
5760   tree max_index;
5761   tree unfilled_index;
5762   tree unfilled_fields;
5763   tree bit_index;
5764   VEC(constructor_elt,gc) *elements;
5765   struct init_node *pending_elts;
5766   int offset;
5767   int depth;
5768   /* If value nonzero, this value should replace the entire
5769      constructor at this level.  */
5770   struct c_expr replacement_value;
5771   struct constructor_range_stack *range_stack;
5772   char constant;
5773   char simple;
5774   char nonconst;
5775   char implicit;
5776   char erroneous;
5777   char outer;
5778   char incremental;
5779   char designated;
5780 };
5781
5782 static struct constructor_stack *constructor_stack;
5783
5784 /* This stack represents designators from some range designator up to
5785    the last designator in the list.  */
5786
5787 struct constructor_range_stack
5788 {
5789   struct constructor_range_stack *next, *prev;
5790   struct constructor_stack *stack;
5791   tree range_start;
5792   tree index;
5793   tree range_end;
5794   tree fields;
5795 };
5796
5797 static struct constructor_range_stack *constructor_range_stack;
5798
5799 /* This stack records separate initializers that are nested.
5800    Nested initializers can't happen in ANSI C, but GNU C allows them
5801    in cases like { ... (struct foo) { ... } ... }.  */
5802
5803 struct initializer_stack
5804 {
5805   struct initializer_stack *next;
5806   tree decl;
5807   struct constructor_stack *constructor_stack;
5808   struct constructor_range_stack *constructor_range_stack;
5809   VEC(constructor_elt,gc) *elements;
5810   struct spelling *spelling;
5811   struct spelling *spelling_base;
5812   int spelling_size;
5813   char top_level;
5814   char require_constant_value;
5815   char require_constant_elements;
5816 };
5817
5818 static struct initializer_stack *initializer_stack;
5819 \f
5820 /* Prepare to parse and output the initializer for variable DECL.  */
5821
5822 void
5823 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5824 {
5825   const char *locus;
5826   struct initializer_stack *p = XNEW (struct initializer_stack);
5827
5828   p->decl = constructor_decl;
5829   p->require_constant_value = require_constant_value;
5830   p->require_constant_elements = require_constant_elements;
5831   p->constructor_stack = constructor_stack;
5832   p->constructor_range_stack = constructor_range_stack;
5833   p->elements = constructor_elements;
5834   p->spelling = spelling;
5835   p->spelling_base = spelling_base;
5836   p->spelling_size = spelling_size;
5837   p->top_level = constructor_top_level;
5838   p->next = initializer_stack;
5839   initializer_stack = p;
5840
5841   constructor_decl = decl;
5842   constructor_designated = 0;
5843   constructor_top_level = top_level;
5844
5845   if (decl != 0 && decl != error_mark_node)
5846     {
5847       require_constant_value = TREE_STATIC (decl);
5848       require_constant_elements
5849         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5850            /* For a scalar, you can always use any value to initialize,
5851               even within braces.  */
5852            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5853                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5854                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5855                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5856       locus = identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)));
5857     }
5858   else
5859     {
5860       require_constant_value = 0;
5861       require_constant_elements = 0;
5862       locus = _("(anonymous)");
5863     }
5864
5865   constructor_stack = 0;
5866   constructor_range_stack = 0;
5867
5868   missing_braces_mentioned = 0;
5869
5870   spelling_base = 0;
5871   spelling_size = 0;
5872   RESTORE_SPELLING_DEPTH (0);
5873
5874   if (locus)
5875     push_string (locus);
5876 }
5877
5878 void
5879 finish_init (void)
5880 {
5881   struct initializer_stack *p = initializer_stack;
5882
5883   /* Free the whole constructor stack of this initializer.  */
5884   while (constructor_stack)
5885     {
5886       struct constructor_stack *q = constructor_stack;
5887       constructor_stack = q->next;
5888       free (q);
5889     }
5890
5891   gcc_assert (!constructor_range_stack);
5892
5893   /* Pop back to the data of the outer initializer (if any).  */
5894   free (spelling_base);
5895
5896   constructor_decl = p->decl;
5897   require_constant_value = p->require_constant_value;
5898   require_constant_elements = p->require_constant_elements;
5899   constructor_stack = p->constructor_stack;
5900   constructor_range_stack = p->constructor_range_stack;
5901   constructor_elements = p->elements;
5902   spelling = p->spelling;
5903   spelling_base = p->spelling_base;
5904   spelling_size = p->spelling_size;
5905   constructor_top_level = p->top_level;
5906   initializer_stack = p->next;
5907   free (p);
5908 }
5909 \f
5910 /* Call here when we see the initializer is surrounded by braces.
5911    This is instead of a call to push_init_level;
5912    it is matched by a call to pop_init_level.
5913
5914    TYPE is the type to initialize, for a constructor expression.
5915    For an initializer for a decl, TYPE is zero.  */
5916
5917 void
5918 really_start_incremental_init (tree type)
5919 {
5920   struct constructor_stack *p = XNEW (struct constructor_stack);
5921
5922   if (type == 0)
5923     type = TREE_TYPE (constructor_decl);
5924
5925   if (TREE_CODE (type) == VECTOR_TYPE
5926       && TYPE_VECTOR_OPAQUE (type))
5927     error ("opaque vector types cannot be initialized");
5928
5929   p->type = constructor_type;
5930   p->fields = constructor_fields;
5931   p->index = constructor_index;
5932   p->max_index = constructor_max_index;
5933   p->unfilled_index = constructor_unfilled_index;
5934   p->unfilled_fields = constructor_unfilled_fields;
5935   p->bit_index = constructor_bit_index;
5936   p->elements = constructor_elements;
5937   p->constant = constructor_constant;
5938   p->simple = constructor_simple;
5939   p->nonconst = constructor_nonconst;
5940   p->erroneous = constructor_erroneous;
5941   p->pending_elts = constructor_pending_elts;
5942   p->depth = constructor_depth;
5943   p->replacement_value.value = 0;
5944   p->replacement_value.original_code = ERROR_MARK;
5945   p->replacement_value.original_type = NULL;
5946   p->implicit = 0;
5947   p->range_stack = 0;
5948   p->outer = 0;
5949   p->incremental = constructor_incremental;
5950   p->designated = constructor_designated;
5951   p->next = 0;
5952   constructor_stack = p;
5953
5954   constructor_constant = 1;
5955   constructor_simple = 1;
5956   constructor_nonconst = 0;
5957   constructor_depth = SPELLING_DEPTH ();
5958   constructor_elements = 0;
5959   constructor_pending_elts = 0;
5960   constructor_type = type;
5961   constructor_incremental = 1;
5962   constructor_designated = 0;
5963   designator_depth = 0;
5964   designator_erroneous = 0;
5965
5966   if (TREE_CODE (constructor_type) == RECORD_TYPE
5967       || TREE_CODE (constructor_type) == UNION_TYPE)
5968     {
5969       constructor_fields = TYPE_FIELDS (constructor_type);
5970       /* Skip any nameless bit fields at the beginning.  */
5971       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5972              && DECL_NAME (constructor_fields) == 0)
5973         constructor_fields = TREE_CHAIN (constructor_fields);
5974
5975       constructor_unfilled_fields = constructor_fields;
5976       constructor_bit_index = bitsize_zero_node;
5977     }
5978   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5979     {
5980       if (TYPE_DOMAIN (constructor_type))
5981         {
5982           constructor_max_index
5983             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5984
5985           /* Detect non-empty initializations of zero-length arrays.  */
5986           if (constructor_max_index == NULL_TREE
5987               && TYPE_SIZE (constructor_type))
5988             constructor_max_index = build_int_cst (NULL_TREE, -1);
5989
5990           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5991              to initialize VLAs will cause a proper error; avoid tree
5992              checking errors as well by setting a safe value.  */
5993           if (constructor_max_index
5994               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5995             constructor_max_index = build_int_cst (NULL_TREE, -1);
5996
5997           constructor_index
5998             = convert (bitsizetype,
5999                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6000         }
6001       else
6002         {
6003           constructor_index = bitsize_zero_node;
6004           constructor_max_index = NULL_TREE;
6005         }
6006
6007       constructor_unfilled_index = constructor_index;
6008     }
6009   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6010     {
6011       /* Vectors are like simple fixed-size arrays.  */
6012       constructor_max_index =
6013         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6014       constructor_index = bitsize_zero_node;
6015       constructor_unfilled_index = constructor_index;
6016     }
6017   else
6018     {
6019       /* Handle the case of int x = {5}; */
6020       constructor_fields = constructor_type;
6021       constructor_unfilled_fields = constructor_type;
6022     }
6023 }
6024 \f
6025 /* Push down into a subobject, for initialization.
6026    If this is for an explicit set of braces, IMPLICIT is 0.
6027    If it is because the next element belongs at a lower level,
6028    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
6029
6030 void
6031 push_init_level (int implicit)
6032 {
6033   struct constructor_stack *p;
6034   tree value = NULL_TREE;
6035
6036   /* If we've exhausted any levels that didn't have braces,
6037      pop them now.  If implicit == 1, this will have been done in
6038      process_init_element; do not repeat it here because in the case
6039      of excess initializers for an empty aggregate this leads to an
6040      infinite cycle of popping a level and immediately recreating
6041      it.  */
6042   if (implicit != 1)
6043     {
6044       while (constructor_stack->implicit)
6045         {
6046           if ((TREE_CODE (constructor_type) == RECORD_TYPE
6047                || TREE_CODE (constructor_type) == UNION_TYPE)
6048               && constructor_fields == 0)
6049             process_init_element (pop_init_level (1), true);
6050           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6051                    && constructor_max_index
6052                    && tree_int_cst_lt (constructor_max_index,
6053                                        constructor_index))
6054             process_init_element (pop_init_level (1), true);
6055           else
6056             break;
6057         }
6058     }
6059
6060   /* Unless this is an explicit brace, we need to preserve previous
6061      content if any.  */
6062   if (implicit)
6063     {
6064       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6065            || TREE_CODE (constructor_type) == UNION_TYPE)
6066           && constructor_fields)
6067         value = find_init_member (constructor_fields);
6068       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6069         value = find_init_member (constructor_index);
6070     }
6071
6072   p = XNEW (struct constructor_stack);
6073   p->type = constructor_type;
6074   p->fields = constructor_fields;
6075   p->index = constructor_index;
6076   p->max_index = constructor_max_index;
6077   p->unfilled_index = constructor_unfilled_index;
6078   p->unfilled_fields = constructor_unfilled_fields;
6079   p->bit_index = constructor_bit_index;
6080   p->elements = constructor_elements;
6081   p->constant = constructor_constant;
6082   p->simple = constructor_simple;
6083   p->nonconst = constructor_nonconst;
6084   p->erroneous = constructor_erroneous;
6085   p->pending_elts = constructor_pending_elts;
6086   p->depth = constructor_depth;
6087   p->replacement_value.value = 0;
6088   p->replacement_value.original_code = ERROR_MARK;
6089   p->replacement_value.original_type = NULL;
6090   p->implicit = implicit;
6091   p->outer = 0;
6092   p->incremental = constructor_incremental;
6093   p->designated = constructor_designated;
6094   p->next = constructor_stack;
6095   p->range_stack = 0;
6096   constructor_stack = p;
6097
6098   constructor_constant = 1;
6099   constructor_simple = 1;
6100   constructor_nonconst = 0;
6101   constructor_depth = SPELLING_DEPTH ();
6102   constructor_elements = 0;
6103   constructor_incremental = 1;
6104   constructor_designated = 0;
6105   constructor_pending_elts = 0;
6106   if (!implicit)
6107     {
6108       p->range_stack = constructor_range_stack;
6109       constructor_range_stack = 0;
6110       designator_depth = 0;
6111       designator_erroneous = 0;
6112     }
6113
6114   /* Don't die if an entire brace-pair level is superfluous
6115      in the containing level.  */
6116   if (constructor_type == 0)
6117     ;
6118   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6119            || TREE_CODE (constructor_type) == UNION_TYPE)
6120     {
6121       /* Don't die if there are extra init elts at the end.  */
6122       if (constructor_fields == 0)
6123         constructor_type = 0;
6124       else
6125         {
6126           constructor_type = TREE_TYPE (constructor_fields);
6127           push_member_name (constructor_fields);
6128           constructor_depth++;
6129         }
6130     }
6131   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6132     {
6133       constructor_type = TREE_TYPE (constructor_type);
6134       push_array_bounds (tree_low_cst (constructor_index, 1));
6135       constructor_depth++;
6136     }
6137
6138   if (constructor_type == 0)
6139     {
6140       error_init ("extra brace group at end of initializer");
6141       constructor_fields = 0;
6142       constructor_unfilled_fields = 0;
6143       return;
6144     }
6145
6146   if (value && TREE_CODE (value) == CONSTRUCTOR)
6147     {
6148       constructor_constant = TREE_CONSTANT (value);
6149       constructor_simple = TREE_STATIC (value);
6150       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
6151       constructor_elements = CONSTRUCTOR_ELTS (value);
6152       if (!VEC_empty (constructor_elt, constructor_elements)
6153           && (TREE_CODE (constructor_type) == RECORD_TYPE
6154               || TREE_CODE (constructor_type) == ARRAY_TYPE))
6155         set_nonincremental_init ();
6156     }
6157
6158   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
6159     {
6160       missing_braces_mentioned = 1;
6161       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
6162     }
6163
6164   if (TREE_CODE (constructor_type) == RECORD_TYPE
6165            || TREE_CODE (constructor_type) == UNION_TYPE)
6166     {
6167       constructor_fields = TYPE_FIELDS (constructor_type);
6168       /* Skip any nameless bit fields at the beginning.  */
6169       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6170              && DECL_NAME (constructor_fields) == 0)
6171         constructor_fields = TREE_CHAIN (constructor_fields);
6172
6173       constructor_unfilled_fields = constructor_fields;
6174       constructor_bit_index = bitsize_zero_node;
6175     }
6176   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6177     {
6178       /* Vectors are like simple fixed-size arrays.  */
6179       constructor_max_index =
6180         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6181       constructor_index = convert (bitsizetype, integer_zero_node);
6182       constructor_unfilled_index = constructor_index;
6183     }
6184   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6185     {
6186       if (TYPE_DOMAIN (constructor_type))
6187         {
6188           constructor_max_index
6189             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6190
6191           /* Detect non-empty initializations of zero-length arrays.  */
6192           if (constructor_max_index == NULL_TREE
6193               && TYPE_SIZE (constructor_type))
6194             constructor_max_index = build_int_cst (NULL_TREE, -1);
6195
6196           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6197              to initialize VLAs will cause a proper error; avoid tree
6198              checking errors as well by setting a safe value.  */
6199           if (constructor_max_index
6200               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6201             constructor_max_index = build_int_cst (NULL_TREE, -1);
6202
6203           constructor_index
6204             = convert (bitsizetype,
6205                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6206         }
6207       else
6208         constructor_index = bitsize_zero_node;
6209
6210       constructor_unfilled_index = constructor_index;
6211       if (value && TREE_CODE (value) == STRING_CST)
6212         {
6213           /* We need to split the char/wchar array into individual
6214              characters, so that we don't have to special case it
6215              everywhere.  */
6216           set_nonincremental_init_from_string (value);
6217         }
6218     }
6219   else
6220     {
6221       if (constructor_type != error_mark_node)
6222         warning_init (0, "braces around scalar initializer");
6223       constructor_fields = constructor_type;
6224       constructor_unfilled_fields = constructor_type;
6225     }
6226 }
6227
6228 /* At the end of an implicit or explicit brace level,
6229    finish up that level of constructor.  If a single expression
6230    with redundant braces initialized that level, return the
6231    c_expr structure for that expression.  Otherwise, the original_code
6232    element is set to ERROR_MARK.
6233    If we were outputting the elements as they are read, return 0 as the value
6234    from inner levels (process_init_element ignores that),
6235    but return error_mark_node as the value from the outermost level
6236    (that's what we want to put in DECL_INITIAL).
6237    Otherwise, return a CONSTRUCTOR expression as the value.  */
6238
6239 struct c_expr
6240 pop_init_level (int implicit)
6241 {
6242   struct constructor_stack *p;
6243   struct c_expr ret;
6244   ret.value = 0;
6245   ret.original_code = ERROR_MARK;
6246   ret.original_type = NULL;
6247
6248   if (implicit == 0)
6249     {
6250       /* When we come to an explicit close brace,
6251          pop any inner levels that didn't have explicit braces.  */
6252       while (constructor_stack->implicit)
6253         process_init_element (pop_init_level (1), true);
6254
6255       gcc_assert (!constructor_range_stack);
6256     }
6257
6258   /* Now output all pending elements.  */
6259   constructor_incremental = 1;
6260   output_pending_init_elements (1);
6261
6262   p = constructor_stack;
6263
6264   /* Error for initializing a flexible array member, or a zero-length
6265      array member in an inappropriate context.  */
6266   if (constructor_type && constructor_fields
6267       && TREE_CODE (constructor_type) == ARRAY_TYPE
6268       && TYPE_DOMAIN (constructor_type)
6269       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6270     {
6271       /* Silently discard empty initializations.  The parser will
6272          already have pedwarned for empty brackets.  */
6273       if (integer_zerop (constructor_unfilled_index))
6274         constructor_type = NULL_TREE;
6275       else
6276         {
6277           gcc_assert (!TYPE_SIZE (constructor_type));
6278
6279           if (constructor_depth > 2)
6280             error_init ("initialization of flexible array member in a nested context");
6281           else
6282             pedwarn_init (input_location, OPT_pedantic,
6283                           "initialization of a flexible array member");
6284
6285           /* We have already issued an error message for the existence
6286              of a flexible array member not at the end of the structure.
6287              Discard the initializer so that we do not die later.  */
6288           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
6289             constructor_type = NULL_TREE;
6290         }
6291     }
6292
6293   /* Warn when some struct elements are implicitly initialized to zero.  */
6294   if (warn_missing_field_initializers
6295       && constructor_type
6296       && TREE_CODE (constructor_type) == RECORD_TYPE
6297       && constructor_unfilled_fields)
6298     {
6299         /* Do not warn for flexible array members or zero-length arrays.  */
6300         while (constructor_unfilled_fields
6301                && (!DECL_SIZE (constructor_unfilled_fields)
6302                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6303           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6304
6305         /* Do not warn if this level of the initializer uses member
6306            designators; it is likely to be deliberate.  */
6307         if (constructor_unfilled_fields && !constructor_designated)
6308           {
6309             push_member_name (constructor_unfilled_fields);
6310             warning_init (OPT_Wmissing_field_initializers,
6311                           "missing initializer");
6312             RESTORE_SPELLING_DEPTH (constructor_depth);
6313           }
6314     }
6315
6316   /* Pad out the end of the structure.  */
6317   if (p->replacement_value.value)
6318     /* If this closes a superfluous brace pair,
6319        just pass out the element between them.  */
6320     ret = p->replacement_value;
6321   else if (constructor_type == 0)
6322     ;
6323   else if (TREE_CODE (constructor_type) != RECORD_TYPE
6324            && TREE_CODE (constructor_type) != UNION_TYPE
6325            && TREE_CODE (constructor_type) != ARRAY_TYPE
6326            && TREE_CODE (constructor_type) != VECTOR_TYPE)
6327     {
6328       /* A nonincremental scalar initializer--just return
6329          the element, after verifying there is just one.  */
6330       if (VEC_empty (constructor_elt,constructor_elements))
6331         {
6332           if (!constructor_erroneous)
6333             error_init ("empty scalar initializer");
6334           ret.value = error_mark_node;
6335         }
6336       else if (VEC_length (constructor_elt,constructor_elements) != 1)
6337         {
6338           error_init ("extra elements in scalar initializer");
6339           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6340         }
6341       else
6342         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6343     }
6344   else
6345     {
6346       if (constructor_erroneous)
6347         ret.value = error_mark_node;
6348       else
6349         {
6350           ret.value = build_constructor (constructor_type,
6351                                          constructor_elements);
6352           if (constructor_constant)
6353             TREE_CONSTANT (ret.value) = 1;
6354           if (constructor_constant && constructor_simple)
6355             TREE_STATIC (ret.value) = 1;
6356           if (constructor_nonconst)
6357             CONSTRUCTOR_NON_CONST (ret.value) = 1;
6358         }
6359     }
6360
6361   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
6362     {
6363       if (constructor_nonconst)
6364         ret.original_code = C_MAYBE_CONST_EXPR;
6365       else if (ret.original_code == C_MAYBE_CONST_EXPR)
6366         ret.original_code = ERROR_MARK;
6367     }
6368
6369   constructor_type = p->type;
6370   constructor_fields = p->fields;
6371   constructor_index = p->index;
6372   constructor_max_index = p->max_index;
6373   constructor_unfilled_index = p->unfilled_index;
6374   constructor_unfilled_fields = p->unfilled_fields;
6375   constructor_bit_index = p->bit_index;
6376   constructor_elements = p->elements;
6377   constructor_constant = p->constant;
6378   constructor_simple = p->simple;
6379   constructor_nonconst = p->nonconst;
6380   constructor_erroneous = p->erroneous;
6381   constructor_incremental = p->incremental;
6382   constructor_designated = p->designated;
6383   constructor_pending_elts = p->pending_elts;
6384   constructor_depth = p->depth;
6385   if (!p->implicit)
6386     constructor_range_stack = p->range_stack;
6387   RESTORE_SPELLING_DEPTH (constructor_depth);
6388
6389   constructor_stack = p->next;
6390   free (p);
6391
6392   if (ret.value == 0 && constructor_stack == 0)
6393     ret.value = error_mark_node;
6394   return ret;
6395 }
6396
6397 /* Common handling for both array range and field name designators.
6398    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
6399
6400 static int
6401 set_designator (int array)
6402 {
6403   tree subtype;
6404   enum tree_code subcode;
6405
6406   /* Don't die if an entire brace-pair level is superfluous
6407      in the containing level.  */
6408   if (constructor_type == 0)
6409     return 1;
6410
6411   /* If there were errors in this designator list already, bail out
6412      silently.  */
6413   if (designator_erroneous)
6414     return 1;
6415
6416   if (!designator_depth)
6417     {
6418       gcc_assert (!constructor_range_stack);
6419
6420       /* Designator list starts at the level of closest explicit
6421          braces.  */
6422       while (constructor_stack->implicit)
6423         process_init_element (pop_init_level (1), true);
6424       constructor_designated = 1;
6425       return 0;
6426     }
6427
6428   switch (TREE_CODE (constructor_type))
6429     {
6430     case  RECORD_TYPE:
6431     case  UNION_TYPE:
6432       subtype = TREE_TYPE (constructor_fields);
6433       if (subtype != error_mark_node)
6434         subtype = TYPE_MAIN_VARIANT (subtype);
6435       break;
6436     case ARRAY_TYPE:
6437       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6438       break;
6439     default:
6440       gcc_unreachable ();
6441     }
6442
6443   subcode = TREE_CODE (subtype);
6444   if (array && subcode != ARRAY_TYPE)
6445     {
6446       error_init ("array index in non-array initializer");
6447       return 1;
6448     }
6449   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
6450     {
6451       error_init ("field name not in record or union initializer");
6452       return 1;
6453     }
6454
6455   constructor_designated = 1;
6456   push_init_level (2);
6457   return 0;
6458 }
6459
6460 /* If there are range designators in designator list, push a new designator
6461    to constructor_range_stack.  RANGE_END is end of such stack range or
6462    NULL_TREE if there is no range designator at this level.  */
6463
6464 static void
6465 push_range_stack (tree range_end)
6466 {
6467   struct constructor_range_stack *p;
6468
6469   p = GGC_NEW (struct constructor_range_stack);
6470   p->prev = constructor_range_stack;
6471   p->next = 0;
6472   p->fields = constructor_fields;
6473   p->range_start = constructor_index;
6474   p->index = constructor_index;
6475   p->stack = constructor_stack;
6476   p->range_end = range_end;
6477   if (constructor_range_stack)
6478     constructor_range_stack->next = p;
6479   constructor_range_stack = p;
6480 }
6481
6482 /* Within an array initializer, specify the next index to be initialized.
6483    FIRST is that index.  If LAST is nonzero, then initialize a range
6484    of indices, running from FIRST through LAST.  */
6485
6486 void
6487 set_init_index (tree first, tree last)
6488 {
6489   if (set_designator (1))
6490     return;
6491
6492   designator_erroneous = 1;
6493
6494   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
6495       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
6496     {
6497       error_init ("array index in initializer not of integer type");
6498       return;
6499     }
6500
6501   if (TREE_CODE (first) != INTEGER_CST)
6502     {
6503       first = c_fully_fold (first, false, NULL);
6504       if (TREE_CODE (first) == INTEGER_CST)
6505         pedwarn_init (input_location, OPT_pedantic,
6506                       "array index in initializer is not "
6507                       "an integer constant expression");
6508     }
6509
6510   if (last && TREE_CODE (last) != INTEGER_CST)
6511     {
6512       last = c_fully_fold (last, false, NULL);
6513       if (TREE_CODE (last) == INTEGER_CST)
6514         pedwarn_init (input_location, OPT_pedantic,
6515                       "array index in initializer is not "
6516                       "an integer constant expression");
6517     }
6518
6519   if (TREE_CODE (first) != INTEGER_CST)
6520     error_init ("nonconstant array index in initializer");
6521   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
6522     error_init ("nonconstant array index in initializer");
6523   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
6524     error_init ("array index in non-array initializer");
6525   else if (tree_int_cst_sgn (first) == -1)
6526     error_init ("array index in initializer exceeds array bounds");
6527   else if (constructor_max_index
6528            && tree_int_cst_lt (constructor_max_index, first))
6529     error_init ("array index in initializer exceeds array bounds");
6530   else
6531     {
6532       constant_expression_warning (first);
6533       if (last)
6534         constant_expression_warning (last);
6535       constructor_index = convert (bitsizetype, first);
6536
6537       if (last)
6538         {
6539           if (tree_int_cst_equal (first, last))
6540             last = 0;
6541           else if (tree_int_cst_lt (last, first))
6542             {
6543               error_init ("empty index range in initializer");
6544               last = 0;
6545             }
6546           else
6547             {
6548               last = convert (bitsizetype, last);
6549               if (constructor_max_index != 0
6550                   && tree_int_cst_lt (constructor_max_index, last))
6551                 {
6552                   error_init ("array index range in initializer exceeds array bounds");
6553                   last = 0;
6554                 }
6555             }
6556         }
6557
6558       designator_depth++;
6559       designator_erroneous = 0;
6560       if (constructor_range_stack || last)
6561         push_range_stack (last);
6562     }
6563 }
6564
6565 /* Within a struct initializer, specify the next field to be initialized.  */
6566
6567 void
6568 set_init_label (tree fieldname)
6569 {
6570   tree tail;
6571
6572   if (set_designator (0))
6573     return;
6574
6575   designator_erroneous = 1;
6576
6577   if (TREE_CODE (constructor_type) != RECORD_TYPE
6578       && TREE_CODE (constructor_type) != UNION_TYPE)
6579     {
6580       error_init ("field name not in record or union initializer");
6581       return;
6582     }
6583
6584   for (tail = TYPE_FIELDS (constructor_type); tail;
6585        tail = TREE_CHAIN (tail))
6586     {
6587       if (DECL_NAME (tail) == fieldname)
6588         break;
6589     }
6590
6591   if (tail == 0)
6592     error ("unknown field %qE specified in initializer", fieldname);
6593   else
6594     {
6595       constructor_fields = tail;
6596       designator_depth++;
6597       designator_erroneous = 0;
6598       if (constructor_range_stack)
6599         push_range_stack (NULL_TREE);
6600     }
6601 }
6602 \f
6603 /* Add a new initializer to the tree of pending initializers.  PURPOSE
6604    identifies the initializer, either array index or field in a structure.
6605    VALUE is the value of that index or field.  If ORIGTYPE is not
6606    NULL_TREE, it is the original type of VALUE.
6607
6608    IMPLICIT is true if value comes from pop_init_level (1),
6609    the new initializer has been merged with the existing one
6610    and thus no warnings should be emitted about overriding an
6611    existing initializer.  */
6612
6613 static void
6614 add_pending_init (tree purpose, tree value, tree origtype, bool implicit)
6615 {
6616   struct init_node *p, **q, *r;
6617
6618   q = &constructor_pending_elts;
6619   p = 0;
6620
6621   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6622     {
6623       while (*q != 0)
6624         {
6625           p = *q;
6626           if (tree_int_cst_lt (purpose, p->purpose))
6627             q = &p->left;
6628           else if (tree_int_cst_lt (p->purpose, purpose))
6629             q = &p->right;
6630           else
6631             {
6632               if (!implicit)
6633                 {
6634                   if (TREE_SIDE_EFFECTS (p->value))
6635                     warning_init (0, "initialized field with side-effects overwritten");
6636                   else if (warn_override_init)
6637                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6638                 }
6639               p->value = value;
6640               p->origtype = origtype;
6641               return;
6642             }
6643         }
6644     }
6645   else
6646     {
6647       tree bitpos;
6648
6649       bitpos = bit_position (purpose);
6650       while (*q != NULL)
6651         {
6652           p = *q;
6653           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6654             q = &p->left;
6655           else if (p->purpose != purpose)
6656             q = &p->right;
6657           else
6658             {
6659               if (!implicit)
6660                 {
6661                   if (TREE_SIDE_EFFECTS (p->value))
6662                     warning_init (0, "initialized field with side-effects overwritten");
6663                   else if (warn_override_init)
6664                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6665                 }
6666               p->value = value;
6667               p->origtype = origtype;
6668               return;
6669             }
6670         }
6671     }
6672
6673   r = GGC_NEW (struct init_node);
6674   r->purpose = purpose;
6675   r->value = value;
6676   r->origtype = origtype;
6677
6678   *q = r;
6679   r->parent = p;
6680   r->left = 0;
6681   r->right = 0;
6682   r->balance = 0;
6683
6684   while (p)
6685     {
6686       struct init_node *s;
6687
6688       if (r == p->left)
6689         {
6690           if (p->balance == 0)
6691             p->balance = -1;
6692           else if (p->balance < 0)
6693             {
6694               if (r->balance < 0)
6695                 {
6696                   /* L rotation.  */
6697                   p->left = r->right;
6698                   if (p->left)
6699                     p->left->parent = p;
6700                   r->right = p;
6701
6702                   p->balance = 0;
6703                   r->balance = 0;
6704
6705                   s = p->parent;
6706                   p->parent = r;
6707                   r->parent = s;
6708                   if (s)
6709                     {
6710                       if (s->left == p)
6711                         s->left = r;
6712                       else
6713                         s->right = r;
6714                     }
6715                   else
6716                     constructor_pending_elts = r;
6717                 }
6718               else
6719                 {
6720                   /* LR rotation.  */
6721                   struct init_node *t = r->right;
6722
6723                   r->right = t->left;
6724                   if (r->right)
6725                     r->right->parent = r;
6726                   t->left = r;
6727
6728                   p->left = t->right;
6729                   if (p->left)
6730                     p->left->parent = p;
6731                   t->right = p;
6732
6733                   p->balance = t->balance < 0;
6734                   r->balance = -(t->balance > 0);
6735                   t->balance = 0;
6736
6737                   s = p->parent;
6738                   p->parent = t;
6739                   r->parent = t;
6740                   t->parent = s;
6741                   if (s)
6742                     {
6743                       if (s->left == p)
6744                         s->left = t;
6745                       else
6746                         s->right = t;
6747                     }
6748                   else
6749                     constructor_pending_elts = t;
6750                 }
6751               break;
6752             }
6753           else
6754             {
6755               /* p->balance == +1; growth of left side balances the node.  */
6756               p->balance = 0;
6757               break;
6758             }
6759         }
6760       else /* r == p->right */
6761         {
6762           if (p->balance == 0)
6763             /* Growth propagation from right side.  */
6764             p->balance++;
6765           else if (p->balance > 0)
6766             {
6767               if (r->balance > 0)
6768                 {
6769                   /* R rotation.  */
6770                   p->right = r->left;
6771                   if (p->right)
6772                     p->right->parent = p;
6773                   r->left = p;
6774
6775                   p->balance = 0;
6776                   r->balance = 0;
6777
6778                   s = p->parent;
6779                   p->parent = r;
6780                   r->parent = s;
6781                   if (s)
6782                     {
6783                       if (s->left == p)
6784                         s->left = r;
6785                       else
6786                         s->right = r;
6787                     }
6788                   else
6789                     constructor_pending_elts = r;
6790                 }
6791               else /* r->balance == -1 */
6792                 {
6793                   /* RL rotation */
6794                   struct init_node *t = r->left;
6795
6796                   r->left = t->right;
6797                   if (r->left)
6798                     r->left->parent = r;
6799                   t->right = r;
6800
6801                   p->right = t->left;
6802                   if (p->right)
6803                     p->right->parent = p;
6804                   t->left = p;
6805
6806                   r->balance = (t->balance < 0);
6807                   p->balance = -(t->balance > 0);
6808                   t->balance = 0;
6809
6810                   s = p->parent;
6811                   p->parent = t;
6812                   r->parent = t;
6813                   t->parent = s;
6814                   if (s)
6815                     {
6816                       if (s->left == p)
6817                         s->left = t;
6818                       else
6819                         s->right = t;
6820                     }
6821                   else
6822                     constructor_pending_elts = t;
6823                 }
6824               break;
6825             }
6826           else
6827             {
6828               /* p->balance == -1; growth of right side balances the node.  */
6829               p->balance = 0;
6830               break;
6831             }
6832         }
6833
6834       r = p;
6835       p = p->parent;
6836     }
6837 }
6838
6839 /* Build AVL tree from a sorted chain.  */
6840
6841 static void
6842 set_nonincremental_init (void)
6843 {
6844   unsigned HOST_WIDE_INT ix;
6845   tree index, value;
6846
6847   if (TREE_CODE (constructor_type) != RECORD_TYPE
6848       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6849     return;
6850
6851   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6852     add_pending_init (index, value, NULL_TREE, false);
6853   constructor_elements = 0;
6854   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6855     {
6856       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6857       /* Skip any nameless bit fields at the beginning.  */
6858       while (constructor_unfilled_fields != 0
6859              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6860              && DECL_NAME (constructor_unfilled_fields) == 0)
6861         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6862
6863     }
6864   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6865     {
6866       if (TYPE_DOMAIN (constructor_type))
6867         constructor_unfilled_index
6868             = convert (bitsizetype,
6869                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6870       else
6871         constructor_unfilled_index = bitsize_zero_node;
6872     }
6873   constructor_incremental = 0;
6874 }
6875
6876 /* Build AVL tree from a string constant.  */
6877
6878 static void
6879 set_nonincremental_init_from_string (tree str)
6880 {
6881   tree value, purpose, type;
6882   HOST_WIDE_INT val[2];
6883   const char *p, *end;
6884   int byte, wchar_bytes, charwidth, bitpos;
6885
6886   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6887
6888   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
6889   charwidth = TYPE_PRECISION (char_type_node);
6890   type = TREE_TYPE (constructor_type);
6891   p = TREE_STRING_POINTER (str);
6892   end = p + TREE_STRING_LENGTH (str);
6893
6894   for (purpose = bitsize_zero_node;
6895        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6896        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6897     {
6898       if (wchar_bytes == 1)
6899         {
6900           val[1] = (unsigned char) *p++;
6901           val[0] = 0;
6902         }
6903       else
6904         {
6905           val[0] = 0;
6906           val[1] = 0;
6907           for (byte = 0; byte < wchar_bytes; byte++)
6908             {
6909               if (BYTES_BIG_ENDIAN)
6910                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6911               else
6912                 bitpos = byte * charwidth;
6913               val[bitpos < HOST_BITS_PER_WIDE_INT]
6914                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6915                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6916             }
6917         }
6918
6919       if (!TYPE_UNSIGNED (type))
6920         {
6921           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6922           if (bitpos < HOST_BITS_PER_WIDE_INT)
6923             {
6924               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6925                 {
6926                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6927                   val[0] = -1;
6928                 }
6929             }
6930           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6931             {
6932               if (val[1] < 0)
6933                 val[0] = -1;
6934             }
6935           else if (val[0] & (((HOST_WIDE_INT) 1)
6936                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6937             val[0] |= ((HOST_WIDE_INT) -1)
6938                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6939         }
6940
6941       value = build_int_cst_wide (type, val[1], val[0]);
6942       add_pending_init (purpose, value, NULL_TREE, false);
6943     }
6944
6945   constructor_incremental = 0;
6946 }
6947
6948 /* Return value of FIELD in pending initializer or zero if the field was
6949    not initialized yet.  */
6950
6951 static tree
6952 find_init_member (tree field)
6953 {
6954   struct init_node *p;
6955
6956   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6957     {
6958       if (constructor_incremental
6959           && tree_int_cst_lt (field, constructor_unfilled_index))
6960         set_nonincremental_init ();
6961
6962       p = constructor_pending_elts;
6963       while (p)
6964         {
6965           if (tree_int_cst_lt (field, p->purpose))
6966             p = p->left;
6967           else if (tree_int_cst_lt (p->purpose, field))
6968             p = p->right;
6969           else
6970             return p->value;
6971         }
6972     }
6973   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6974     {
6975       tree bitpos = bit_position (field);
6976
6977       if (constructor_incremental
6978           && (!constructor_unfilled_fields
6979               || tree_int_cst_lt (bitpos,
6980                                   bit_position (constructor_unfilled_fields))))
6981         set_nonincremental_init ();
6982
6983       p = constructor_pending_elts;
6984       while (p)
6985         {
6986           if (field == p->purpose)
6987             return p->value;
6988           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6989             p = p->left;
6990           else
6991             p = p->right;
6992         }
6993     }
6994   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6995     {
6996       if (!VEC_empty (constructor_elt, constructor_elements)
6997           && (VEC_last (constructor_elt, constructor_elements)->index
6998               == field))
6999         return VEC_last (constructor_elt, constructor_elements)->value;
7000     }
7001   return 0;
7002 }
7003
7004 /* "Output" the next constructor element.
7005    At top level, really output it to assembler code now.
7006    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
7007    If ORIGTYPE is not NULL_TREE, it is the original type of VALUE.
7008    TYPE is the data type that the containing data type wants here.
7009    FIELD is the field (a FIELD_DECL) or the index that this element fills.
7010    If VALUE is a string constant, STRICT_STRING is true if it is
7011    unparenthesized or we should not warn here for it being parenthesized.
7012    For other types of VALUE, STRICT_STRING is not used.
7013
7014    PENDING if non-nil means output pending elements that belong
7015    right after this element.  (PENDING is normally 1;
7016    it is 0 while outputting pending elements, to avoid recursion.)
7017
7018    IMPLICIT is true if value comes from pop_init_level (1),
7019    the new initializer has been merged with the existing one
7020    and thus no warnings should be emitted about overriding an
7021    existing initializer.  */
7022
7023 static void
7024 output_init_element (tree value, tree origtype, bool strict_string, tree type,
7025                      tree field, int pending, bool implicit)
7026 {
7027   tree semantic_type = NULL_TREE;
7028   constructor_elt *celt;
7029   bool maybe_const = true;
7030   bool npc;
7031
7032   if (type == error_mark_node || value == error_mark_node)
7033     {
7034       constructor_erroneous = 1;
7035       return;
7036     }
7037   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
7038       && (TREE_CODE (value) == STRING_CST
7039           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
7040       && !(TREE_CODE (value) == STRING_CST
7041            && TREE_CODE (type) == ARRAY_TYPE
7042            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
7043       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
7044                      TYPE_MAIN_VARIANT (type)))
7045     value = array_to_pointer_conversion (value);
7046
7047   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
7048       && require_constant_value && !flag_isoc99 && pending)
7049     {
7050       /* As an extension, allow initializing objects with static storage
7051          duration with compound literals (which are then treated just as
7052          the brace enclosed list they contain).  */
7053       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
7054       value = DECL_INITIAL (decl);
7055     }
7056
7057   npc = null_pointer_constant_p (value);
7058   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
7059     {
7060       semantic_type = TREE_TYPE (value);
7061       value = TREE_OPERAND (value, 0);
7062     }
7063   value = c_fully_fold (value, require_constant_value, &maybe_const);
7064
7065   if (value == error_mark_node)
7066     constructor_erroneous = 1;
7067   else if (!TREE_CONSTANT (value))
7068     constructor_constant = 0;
7069   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
7070            || ((TREE_CODE (constructor_type) == RECORD_TYPE
7071                 || TREE_CODE (constructor_type) == UNION_TYPE)
7072                && DECL_C_BIT_FIELD (field)
7073                && TREE_CODE (value) != INTEGER_CST))
7074     constructor_simple = 0;
7075   if (!maybe_const)
7076     constructor_nonconst = 1;
7077
7078   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
7079     {
7080       if (require_constant_value)
7081         {
7082           error_init ("initializer element is not constant");
7083           value = error_mark_node;
7084         }
7085       else if (require_constant_elements)
7086         pedwarn (input_location, 0,
7087                  "initializer element is not computable at load time");
7088     }
7089   else if (!maybe_const
7090            && (require_constant_value || require_constant_elements))
7091     pedwarn_init (input_location, 0,
7092                   "initializer element is not a constant expression");
7093
7094   /* Issue -Wc++-compat warnings about initializing a bitfield with
7095      enum type.  */
7096   if (warn_cxx_compat
7097       && field != NULL_TREE
7098       && TREE_CODE (field) == FIELD_DECL
7099       && DECL_BIT_FIELD_TYPE (field) != NULL_TREE
7100       && (TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))
7101           != TYPE_MAIN_VARIANT (type))
7102       && TREE_CODE (DECL_BIT_FIELD_TYPE (field)) == ENUMERAL_TYPE)
7103     {
7104       tree checktype = origtype != NULL_TREE ? origtype : TREE_TYPE (value);
7105       if (checktype != error_mark_node
7106           && (TYPE_MAIN_VARIANT (checktype)
7107               != TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))))
7108         warning_init (OPT_Wc___compat,
7109                       "enum conversion in initialization is invalid in C++");
7110     }
7111
7112   /* If this field is empty (and not at the end of structure),
7113      don't do anything other than checking the initializer.  */
7114   if (field
7115       && (TREE_TYPE (field) == error_mark_node
7116           || (COMPLETE_TYPE_P (TREE_TYPE (field))
7117               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
7118               && (TREE_CODE (constructor_type) == ARRAY_TYPE
7119                   || TREE_CHAIN (field)))))
7120     return;
7121
7122   if (semantic_type)
7123     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
7124   value = digest_init (type, value, origtype, npc, strict_string,
7125                        require_constant_value);
7126   if (value == error_mark_node)
7127     {
7128       constructor_erroneous = 1;
7129       return;
7130     }
7131   if (require_constant_value || require_constant_elements)
7132     constant_expression_warning (value);
7133
7134   /* If this element doesn't come next in sequence,
7135      put it on constructor_pending_elts.  */
7136   if (TREE_CODE (constructor_type) == ARRAY_TYPE
7137       && (!constructor_incremental
7138           || !tree_int_cst_equal (field, constructor_unfilled_index)))
7139     {
7140       if (constructor_incremental
7141           && tree_int_cst_lt (field, constructor_unfilled_index))
7142         set_nonincremental_init ();
7143
7144       add_pending_init (field, value, origtype, implicit);
7145       return;
7146     }
7147   else if (TREE_CODE (constructor_type) == RECORD_TYPE
7148            && (!constructor_incremental
7149                || field != constructor_unfilled_fields))
7150     {
7151       /* We do this for records but not for unions.  In a union,
7152          no matter which field is specified, it can be initialized
7153          right away since it starts at the beginning of the union.  */
7154       if (constructor_incremental)
7155         {
7156           if (!constructor_unfilled_fields)
7157             set_nonincremental_init ();
7158           else
7159             {
7160               tree bitpos, unfillpos;
7161
7162               bitpos = bit_position (field);
7163               unfillpos = bit_position (constructor_unfilled_fields);
7164
7165               if (tree_int_cst_lt (bitpos, unfillpos))
7166                 set_nonincremental_init ();
7167             }
7168         }
7169
7170       add_pending_init (field, value, origtype, implicit);
7171       return;
7172     }
7173   else if (TREE_CODE (constructor_type) == UNION_TYPE
7174            && !VEC_empty (constructor_elt, constructor_elements))
7175     {
7176       if (!implicit)
7177         {
7178           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
7179                                            constructor_elements)->value))
7180             warning_init (0,
7181                           "initialized field with side-effects overwritten");
7182           else if (warn_override_init)
7183             warning_init (OPT_Woverride_init, "initialized field overwritten");
7184         }
7185
7186       /* We can have just one union field set.  */
7187       constructor_elements = 0;
7188     }
7189
7190   /* Otherwise, output this element either to
7191      constructor_elements or to the assembler file.  */
7192
7193   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
7194   celt->index = field;
7195   celt->value = value;
7196
7197   /* Advance the variable that indicates sequential elements output.  */
7198   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7199     constructor_unfilled_index
7200       = size_binop (PLUS_EXPR, constructor_unfilled_index,
7201                     bitsize_one_node);
7202   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7203     {
7204       constructor_unfilled_fields
7205         = TREE_CHAIN (constructor_unfilled_fields);
7206
7207       /* Skip any nameless bit fields.  */
7208       while (constructor_unfilled_fields != 0
7209              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7210              && DECL_NAME (constructor_unfilled_fields) == 0)
7211         constructor_unfilled_fields =
7212           TREE_CHAIN (constructor_unfilled_fields);
7213     }
7214   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7215     constructor_unfilled_fields = 0;
7216
7217   /* Now output any pending elements which have become next.  */
7218   if (pending)
7219     output_pending_init_elements (0);
7220 }
7221
7222 /* Output any pending elements which have become next.
7223    As we output elements, constructor_unfilled_{fields,index}
7224    advances, which may cause other elements to become next;
7225    if so, they too are output.
7226
7227    If ALL is 0, we return when there are
7228    no more pending elements to output now.
7229
7230    If ALL is 1, we output space as necessary so that
7231    we can output all the pending elements.  */
7232
7233 static void
7234 output_pending_init_elements (int all)
7235 {
7236   struct init_node *elt = constructor_pending_elts;
7237   tree next;
7238
7239  retry:
7240
7241   /* Look through the whole pending tree.
7242      If we find an element that should be output now,
7243      output it.  Otherwise, set NEXT to the element
7244      that comes first among those still pending.  */
7245
7246   next = 0;
7247   while (elt)
7248     {
7249       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7250         {
7251           if (tree_int_cst_equal (elt->purpose,
7252                                   constructor_unfilled_index))
7253             output_init_element (elt->value, elt->origtype, true,
7254                                  TREE_TYPE (constructor_type),
7255                                  constructor_unfilled_index, 0, false);
7256           else if (tree_int_cst_lt (constructor_unfilled_index,
7257                                     elt->purpose))
7258             {
7259               /* Advance to the next smaller node.  */
7260               if (elt->left)
7261                 elt = elt->left;
7262               else
7263                 {
7264                   /* We have reached the smallest node bigger than the
7265                      current unfilled index.  Fill the space first.  */
7266                   next = elt->purpose;
7267                   break;
7268                 }
7269             }
7270           else
7271             {
7272               /* Advance to the next bigger node.  */
7273               if (elt->right)
7274                 elt = elt->right;
7275               else
7276                 {
7277                   /* We have reached the biggest node in a subtree.  Find
7278                      the parent of it, which is the next bigger node.  */
7279                   while (elt->parent && elt->parent->right == elt)
7280                     elt = elt->parent;
7281                   elt = elt->parent;
7282                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7283                                               elt->purpose))
7284                     {
7285                       next = elt->purpose;
7286                       break;
7287                     }
7288                 }
7289             }
7290         }
7291       else if (TREE_CODE (constructor_type) == RECORD_TYPE
7292                || TREE_CODE (constructor_type) == UNION_TYPE)
7293         {
7294           tree ctor_unfilled_bitpos, elt_bitpos;
7295
7296           /* If the current record is complete we are done.  */
7297           if (constructor_unfilled_fields == 0)
7298             break;
7299
7300           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
7301           elt_bitpos = bit_position (elt->purpose);
7302           /* We can't compare fields here because there might be empty
7303              fields in between.  */
7304           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
7305             {
7306               constructor_unfilled_fields = elt->purpose;
7307               output_init_element (elt->value, elt->origtype, true,
7308                                    TREE_TYPE (elt->purpose),
7309                                    elt->purpose, 0, false);
7310             }
7311           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
7312             {
7313               /* Advance to the next smaller node.  */
7314               if (elt->left)
7315                 elt = elt->left;
7316               else
7317                 {
7318                   /* We have reached the smallest node bigger than the
7319                      current unfilled field.  Fill the space first.  */
7320                   next = elt->purpose;
7321                   break;
7322                 }
7323             }
7324           else
7325             {
7326               /* Advance to the next bigger node.  */
7327               if (elt->right)
7328                 elt = elt->right;
7329               else
7330                 {
7331                   /* We have reached the biggest node in a subtree.  Find
7332                      the parent of it, which is the next bigger node.  */
7333                   while (elt->parent && elt->parent->right == elt)
7334                     elt = elt->parent;
7335                   elt = elt->parent;
7336                   if (elt
7337                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
7338                                            bit_position (elt->purpose))))
7339                     {
7340                       next = elt->purpose;
7341                       break;
7342                     }
7343                 }
7344             }
7345         }
7346     }
7347
7348   /* Ordinarily return, but not if we want to output all
7349      and there are elements left.  */
7350   if (!(all && next != 0))
7351     return;
7352
7353   /* If it's not incremental, just skip over the gap, so that after
7354      jumping to retry we will output the next successive element.  */
7355   if (TREE_CODE (constructor_type) == RECORD_TYPE
7356       || TREE_CODE (constructor_type) == UNION_TYPE)
7357     constructor_unfilled_fields = next;
7358   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7359     constructor_unfilled_index = next;
7360
7361   /* ELT now points to the node in the pending tree with the next
7362      initializer to output.  */
7363   goto retry;
7364 }
7365 \f
7366 /* Add one non-braced element to the current constructor level.
7367    This adjusts the current position within the constructor's type.
7368    This may also start or terminate implicit levels
7369    to handle a partly-braced initializer.
7370
7371    Once this has found the correct level for the new element,
7372    it calls output_init_element.
7373
7374    IMPLICIT is true if value comes from pop_init_level (1),
7375    the new initializer has been merged with the existing one
7376    and thus no warnings should be emitted about overriding an
7377    existing initializer.  */
7378
7379 void
7380 process_init_element (struct c_expr value, bool implicit)
7381 {
7382   tree orig_value = value.value;
7383   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
7384   bool strict_string = value.original_code == STRING_CST;
7385
7386   designator_depth = 0;
7387   designator_erroneous = 0;
7388
7389   /* Handle superfluous braces around string cst as in
7390      char x[] = {"foo"}; */
7391   if (string_flag
7392       && constructor_type
7393       && TREE_CODE (constructor_type) == ARRAY_TYPE
7394       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
7395       && integer_zerop (constructor_unfilled_index))
7396     {
7397       if (constructor_stack->replacement_value.value)
7398         error_init ("excess elements in char array initializer");
7399       constructor_stack->replacement_value = value;
7400       return;
7401     }
7402
7403   if (constructor_stack->replacement_value.value != 0)
7404     {
7405       error_init ("excess elements in struct initializer");
7406       return;
7407     }
7408
7409   /* Ignore elements of a brace group if it is entirely superfluous
7410      and has already been diagnosed.  */
7411   if (constructor_type == 0)
7412     return;
7413
7414   /* If we've exhausted any levels that didn't have braces,
7415      pop them now.  */
7416   while (constructor_stack->implicit)
7417     {
7418       if ((TREE_CODE (constructor_type) == RECORD_TYPE
7419            || TREE_CODE (constructor_type) == UNION_TYPE)
7420           && constructor_fields == 0)
7421         process_init_element (pop_init_level (1), true);
7422       else if ((TREE_CODE (constructor_type) == ARRAY_TYPE
7423                 || TREE_CODE (constructor_type) == VECTOR_TYPE)
7424                && (constructor_max_index == 0
7425                    || tree_int_cst_lt (constructor_max_index,
7426                                        constructor_index)))
7427         process_init_element (pop_init_level (1), true);
7428       else
7429         break;
7430     }
7431
7432   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
7433   if (constructor_range_stack)
7434     {
7435       /* If value is a compound literal and we'll be just using its
7436          content, don't put it into a SAVE_EXPR.  */
7437       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
7438           || !require_constant_value
7439           || flag_isoc99)
7440         {
7441           tree semantic_type = NULL_TREE;
7442           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
7443             {
7444               semantic_type = TREE_TYPE (value.value);
7445               value.value = TREE_OPERAND (value.value, 0);
7446             }
7447           value.value = c_save_expr (value.value);
7448           if (semantic_type)
7449             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
7450                                   value.value);
7451         }
7452     }
7453
7454   while (1)
7455     {
7456       if (TREE_CODE (constructor_type) == RECORD_TYPE)
7457         {
7458           tree fieldtype;
7459           enum tree_code fieldcode;
7460
7461           if (constructor_fields == 0)
7462             {
7463               pedwarn_init (input_location, 0,
7464                             "excess elements in struct initializer");
7465               break;
7466             }
7467
7468           fieldtype = TREE_TYPE (constructor_fields);
7469           if (fieldtype != error_mark_node)
7470             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7471           fieldcode = TREE_CODE (fieldtype);
7472
7473           /* Error for non-static initialization of a flexible array member.  */
7474           if (fieldcode == ARRAY_TYPE
7475               && !require_constant_value
7476               && TYPE_SIZE (fieldtype) == NULL_TREE
7477               && TREE_CHAIN (constructor_fields) == NULL_TREE)
7478             {
7479               error_init ("non-static initialization of a flexible array member");
7480               break;
7481             }
7482
7483           /* Accept a string constant to initialize a subarray.  */
7484           if (value.value != 0
7485               && fieldcode == ARRAY_TYPE
7486               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7487               && string_flag)
7488             value.value = orig_value;
7489           /* Otherwise, if we have come to a subaggregate,
7490              and we don't have an element of its type, push into it.  */
7491           else if (value.value != 0
7492                    && value.value != error_mark_node
7493                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7494                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7495                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7496             {
7497               push_init_level (1);
7498               continue;
7499             }
7500
7501           if (value.value)
7502             {
7503               push_member_name (constructor_fields);
7504               output_init_element (value.value, value.original_type,
7505                                    strict_string, fieldtype,
7506                                    constructor_fields, 1, implicit);
7507               RESTORE_SPELLING_DEPTH (constructor_depth);
7508             }
7509           else
7510             /* Do the bookkeeping for an element that was
7511                directly output as a constructor.  */
7512             {
7513               /* For a record, keep track of end position of last field.  */
7514               if (DECL_SIZE (constructor_fields))
7515                 constructor_bit_index
7516                   = size_binop (PLUS_EXPR,
7517                                 bit_position (constructor_fields),
7518                                 DECL_SIZE (constructor_fields));
7519
7520               /* If the current field was the first one not yet written out,
7521                  it isn't now, so update.  */
7522               if (constructor_unfilled_fields == constructor_fields)
7523                 {
7524                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7525                   /* Skip any nameless bit fields.  */
7526                   while (constructor_unfilled_fields != 0
7527                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7528                          && DECL_NAME (constructor_unfilled_fields) == 0)
7529                     constructor_unfilled_fields =
7530                       TREE_CHAIN (constructor_unfilled_fields);
7531                 }
7532             }
7533
7534           constructor_fields = TREE_CHAIN (constructor_fields);
7535           /* Skip any nameless bit fields at the beginning.  */
7536           while (constructor_fields != 0
7537                  && DECL_C_BIT_FIELD (constructor_fields)
7538                  && DECL_NAME (constructor_fields) == 0)
7539             constructor_fields = TREE_CHAIN (constructor_fields);
7540         }
7541       else if (TREE_CODE (constructor_type) == UNION_TYPE)
7542         {
7543           tree fieldtype;
7544           enum tree_code fieldcode;
7545
7546           if (constructor_fields == 0)
7547             {
7548               pedwarn_init (input_location, 0,
7549                             "excess elements in union initializer");
7550               break;
7551             }
7552
7553           fieldtype = TREE_TYPE (constructor_fields);
7554           if (fieldtype != error_mark_node)
7555             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7556           fieldcode = TREE_CODE (fieldtype);
7557
7558           /* Warn that traditional C rejects initialization of unions.
7559              We skip the warning if the value is zero.  This is done
7560              under the assumption that the zero initializer in user
7561              code appears conditioned on e.g. __STDC__ to avoid
7562              "missing initializer" warnings and relies on default
7563              initialization to zero in the traditional C case.
7564              We also skip the warning if the initializer is designated,
7565              again on the assumption that this must be conditional on
7566              __STDC__ anyway (and we've already complained about the
7567              member-designator already).  */
7568           if (!in_system_header && !constructor_designated
7569               && !(value.value && (integer_zerop (value.value)
7570                                    || real_zerop (value.value))))
7571             warning (OPT_Wtraditional, "traditional C rejects initialization "
7572                      "of unions");
7573
7574           /* Accept a string constant to initialize a subarray.  */
7575           if (value.value != 0
7576               && fieldcode == ARRAY_TYPE
7577               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7578               && string_flag)
7579             value.value = orig_value;
7580           /* Otherwise, if we have come to a subaggregate,
7581              and we don't have an element of its type, push into it.  */
7582           else if (value.value != 0
7583                    && value.value != error_mark_node
7584                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7585                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7586                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7587             {
7588               push_init_level (1);
7589               continue;
7590             }
7591
7592           if (value.value)
7593             {
7594               push_member_name (constructor_fields);
7595               output_init_element (value.value, value.original_type,
7596                                    strict_string, fieldtype,
7597                                    constructor_fields, 1, implicit);
7598               RESTORE_SPELLING_DEPTH (constructor_depth);
7599             }
7600           else
7601             /* Do the bookkeeping for an element that was
7602                directly output as a constructor.  */
7603             {
7604               constructor_bit_index = DECL_SIZE (constructor_fields);
7605               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7606             }
7607
7608           constructor_fields = 0;
7609         }
7610       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7611         {
7612           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7613           enum tree_code eltcode = TREE_CODE (elttype);
7614
7615           /* Accept a string constant to initialize a subarray.  */
7616           if (value.value != 0
7617               && eltcode == ARRAY_TYPE
7618               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
7619               && string_flag)
7620             value.value = orig_value;
7621           /* Otherwise, if we have come to a subaggregate,
7622              and we don't have an element of its type, push into it.  */
7623           else if (value.value != 0
7624                    && value.value != error_mark_node
7625                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
7626                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
7627                        || eltcode == UNION_TYPE || eltcode == VECTOR_TYPE))
7628             {
7629               push_init_level (1);
7630               continue;
7631             }
7632
7633           if (constructor_max_index != 0
7634               && (tree_int_cst_lt (constructor_max_index, constructor_index)
7635                   || integer_all_onesp (constructor_max_index)))
7636             {
7637               pedwarn_init (input_location, 0,
7638                             "excess elements in array initializer");
7639               break;
7640             }
7641
7642           /* Now output the actual element.  */
7643           if (value.value)
7644             {
7645               push_array_bounds (tree_low_cst (constructor_index, 1));
7646               output_init_element (value.value, value.original_type,
7647                                    strict_string, elttype,
7648                                    constructor_index, 1, implicit);
7649               RESTORE_SPELLING_DEPTH (constructor_depth);
7650             }
7651
7652           constructor_index
7653             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
7654
7655           if (!value.value)
7656             /* If we are doing the bookkeeping for an element that was
7657                directly output as a constructor, we must update
7658                constructor_unfilled_index.  */
7659             constructor_unfilled_index = constructor_index;
7660         }
7661       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
7662         {
7663           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7664
7665          /* Do a basic check of initializer size.  Note that vectors
7666             always have a fixed size derived from their type.  */
7667           if (tree_int_cst_lt (constructor_max_index, constructor_index))
7668             {
7669               pedwarn_init (input_location, 0,
7670                             "excess elements in vector initializer");
7671               break;
7672             }
7673
7674           /* Now output the actual element.  */
7675           if (value.value)
7676             {
7677               if (TREE_CODE (value.value) == VECTOR_CST)
7678                 elttype = TYPE_MAIN_VARIANT (constructor_type);
7679               output_init_element (value.value, value.original_type,
7680                                    strict_string, elttype,
7681                                    constructor_index, 1, implicit);
7682             }
7683
7684           constructor_index
7685             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
7686
7687           if (!value.value)
7688             /* If we are doing the bookkeeping for an element that was
7689                directly output as a constructor, we must update
7690                constructor_unfilled_index.  */
7691             constructor_unfilled_index = constructor_index;
7692         }
7693
7694       /* Handle the sole element allowed in a braced initializer
7695          for a scalar variable.  */
7696       else if (constructor_type != error_mark_node
7697                && constructor_fields == 0)
7698         {
7699           pedwarn_init (input_location, 0,
7700                         "excess elements in scalar initializer");
7701           break;
7702         }
7703       else
7704         {
7705           if (value.value)
7706             output_init_element (value.value, value.original_type,
7707                                  strict_string, constructor_type,
7708                                  NULL_TREE, 1, implicit);
7709           constructor_fields = 0;
7710         }
7711
7712       /* Handle range initializers either at this level or anywhere higher
7713          in the designator stack.  */
7714       if (constructor_range_stack)
7715         {
7716           struct constructor_range_stack *p, *range_stack;
7717           int finish = 0;
7718
7719           range_stack = constructor_range_stack;
7720           constructor_range_stack = 0;
7721           while (constructor_stack != range_stack->stack)
7722             {
7723               gcc_assert (constructor_stack->implicit);
7724               process_init_element (pop_init_level (1), true);
7725             }
7726           for (p = range_stack;
7727                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
7728                p = p->prev)
7729             {
7730               gcc_assert (constructor_stack->implicit);
7731               process_init_element (pop_init_level (1), true);
7732             }
7733
7734           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
7735           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
7736             finish = 1;
7737
7738           while (1)
7739             {
7740               constructor_index = p->index;
7741               constructor_fields = p->fields;
7742               if (finish && p->range_end && p->index == p->range_start)
7743                 {
7744                   finish = 0;
7745                   p->prev = 0;
7746                 }
7747               p = p->next;
7748               if (!p)
7749                 break;
7750               push_init_level (2);
7751               p->stack = constructor_stack;
7752               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
7753                 p->index = p->range_start;
7754             }
7755
7756           if (!finish)
7757             constructor_range_stack = range_stack;
7758           continue;
7759         }
7760
7761       break;
7762     }
7763
7764   constructor_range_stack = 0;
7765 }
7766 \f
7767 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
7768    (guaranteed to be 'volatile' or null) and ARGS (represented using
7769    an ASM_EXPR node).  */
7770 tree
7771 build_asm_stmt (tree cv_qualifier, tree args)
7772 {
7773   if (!ASM_VOLATILE_P (args) && cv_qualifier)
7774     ASM_VOLATILE_P (args) = 1;
7775   return add_stmt (args);
7776 }
7777
7778 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
7779    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
7780    SIMPLE indicates whether there was anything at all after the
7781    string in the asm expression -- asm("blah") and asm("blah" : )
7782    are subtly different.  We use a ASM_EXPR node to represent this.  */
7783 tree
7784 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
7785                 bool simple)
7786 {
7787   tree tail;
7788   tree args;
7789   int i;
7790   const char *constraint;
7791   const char **oconstraints;
7792   bool allows_mem, allows_reg, is_inout;
7793   int ninputs, noutputs;
7794
7795   ninputs = list_length (inputs);
7796   noutputs = list_length (outputs);
7797   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
7798
7799   string = resolve_asm_operand_names (string, outputs, inputs);
7800
7801   /* Remove output conversions that change the type but not the mode.  */
7802   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
7803     {
7804       tree output = TREE_VALUE (tail);
7805
7806       /* ??? Really, this should not be here.  Users should be using a
7807          proper lvalue, dammit.  But there's a long history of using casts
7808          in the output operands.  In cases like longlong.h, this becomes a
7809          primitive form of typechecking -- if the cast can be removed, then
7810          the output operand had a type of the proper width; otherwise we'll
7811          get an error.  Gross, but ...  */
7812       STRIP_NOPS (output);
7813
7814       if (!lvalue_or_else (output, lv_asm))
7815         output = error_mark_node;
7816
7817       if (output != error_mark_node
7818           && (TREE_READONLY (output)
7819               || TYPE_READONLY (TREE_TYPE (output))
7820               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7821                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7822                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7823         readonly_error (output, lv_asm);
7824
7825       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7826       oconstraints[i] = constraint;
7827
7828       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7829                                    &allows_mem, &allows_reg, &is_inout))
7830         {
7831           /* If the operand is going to end up in memory,
7832              mark it addressable.  */
7833           if (!allows_reg && !c_mark_addressable (output))
7834             output = error_mark_node;
7835         }
7836       else
7837         output = error_mark_node;
7838
7839       TREE_VALUE (tail) = output;
7840     }
7841
7842   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7843     {
7844       tree input;
7845
7846       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7847       input = TREE_VALUE (tail);
7848
7849       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7850                                   oconstraints, &allows_mem, &allows_reg))
7851         {
7852           /* If the operand is going to end up in memory,
7853              mark it addressable.  */
7854           if (!allows_reg && allows_mem)
7855             {
7856               /* Strip the nops as we allow this case.  FIXME, this really
7857                  should be rejected or made deprecated.  */
7858               STRIP_NOPS (input);
7859               if (!c_mark_addressable (input))
7860                 input = error_mark_node;
7861           }
7862         }
7863       else
7864         input = error_mark_node;
7865
7866       TREE_VALUE (tail) = input;
7867     }
7868
7869   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7870
7871   /* asm statements without outputs, including simple ones, are treated
7872      as volatile.  */
7873   ASM_INPUT_P (args) = simple;
7874   ASM_VOLATILE_P (args) = (noutputs == 0);
7875
7876   return args;
7877 }
7878 \f
7879 /* Generate a goto statement to LABEL.  */
7880
7881 tree
7882 c_finish_goto_label (tree label)
7883 {
7884   tree decl = lookup_label (label);
7885   if (!decl)
7886     return NULL_TREE;
7887
7888   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7889     {
7890       error ("jump into statement expression");
7891       return NULL_TREE;
7892     }
7893
7894   if (C_DECL_UNJUMPABLE_VM (decl))
7895     {
7896       error ("jump into scope of identifier with variably modified type");
7897       return NULL_TREE;
7898     }
7899
7900   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7901     {
7902       /* No jump from outside this statement expression context, so
7903          record that there is a jump from within this context.  */
7904       struct c_label_list *nlist;
7905       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7906       nlist->next = label_context_stack_se->labels_used;
7907       nlist->label = decl;
7908       label_context_stack_se->labels_used = nlist;
7909     }
7910
7911   if (!C_DECL_UNDEFINABLE_VM (decl))
7912     {
7913       /* No jump from outside this context context of identifiers with
7914          variably modified type, so record that there is a jump from
7915          within this context.  */
7916       struct c_label_list *nlist;
7917       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7918       nlist->next = label_context_stack_vm->labels_used;
7919       nlist->label = decl;
7920       label_context_stack_vm->labels_used = nlist;
7921     }
7922
7923   TREE_USED (decl) = 1;
7924   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7925 }
7926
7927 /* Generate a computed goto statement to EXPR.  */
7928
7929 tree
7930 c_finish_goto_ptr (tree expr)
7931 {
7932   pedwarn (input_location, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
7933   expr = c_fully_fold (expr, false, NULL);
7934   expr = convert (ptr_type_node, expr);
7935   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7936 }
7937
7938 /* Generate a C `return' statement.  RETVAL is the expression for what
7939    to return, or a null pointer for `return;' with no value.  If
7940    ORIGTYPE is not NULL_TREE, it is the original type of RETVAL.  */
7941
7942 tree
7943 c_finish_return (tree retval, tree origtype)
7944 {
7945   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7946   bool no_warning = false;
7947   bool npc = false;
7948
7949   if (TREE_THIS_VOLATILE (current_function_decl))
7950     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7951
7952   if (retval)
7953     {
7954       tree semantic_type = NULL_TREE;
7955       npc = null_pointer_constant_p (retval);
7956       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
7957         {
7958           semantic_type = TREE_TYPE (retval);
7959           retval = TREE_OPERAND (retval, 0);
7960         }
7961       retval = c_fully_fold (retval, false, NULL);
7962       if (semantic_type)
7963         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
7964     }
7965
7966   if (!retval)
7967     {
7968       current_function_returns_null = 1;
7969       if ((warn_return_type || flag_isoc99)
7970           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7971         {
7972           pedwarn_c99 (input_location, flag_isoc99 ? 0 : OPT_Wreturn_type,
7973                        "%<return%> with no value, in "
7974                        "function returning non-void");
7975           no_warning = true;
7976         }
7977     }
7978   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7979     {
7980       current_function_returns_null = 1;
7981       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7982         pedwarn (input_location, 0,
7983                  "%<return%> with a value, in function returning void");
7984       else
7985         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
7986                  "%<return%> with expression, in function returning void");
7987     }
7988   else
7989     {
7990       tree t = convert_for_assignment (valtype, retval, origtype, ic_return,
7991                                        npc, NULL_TREE, NULL_TREE, 0);
7992       tree res = DECL_RESULT (current_function_decl);
7993       tree inner;
7994
7995       current_function_returns_value = 1;
7996       if (t == error_mark_node)
7997         return NULL_TREE;
7998
7999       inner = t = convert (TREE_TYPE (res), t);
8000
8001       /* Strip any conversions, additions, and subtractions, and see if
8002          we are returning the address of a local variable.  Warn if so.  */
8003       while (1)
8004         {
8005           switch (TREE_CODE (inner))
8006             {
8007             CASE_CONVERT:
8008             case NON_LVALUE_EXPR:
8009             case PLUS_EXPR:
8010             case POINTER_PLUS_EXPR:
8011               inner = TREE_OPERAND (inner, 0);
8012               continue;
8013
8014             case MINUS_EXPR:
8015               /* If the second operand of the MINUS_EXPR has a pointer
8016                  type (or is converted from it), this may be valid, so
8017                  don't give a warning.  */
8018               {
8019                 tree op1 = TREE_OPERAND (inner, 1);
8020
8021                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
8022                        && (CONVERT_EXPR_P (op1)
8023                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
8024                   op1 = TREE_OPERAND (op1, 0);
8025
8026                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
8027                   break;
8028
8029                 inner = TREE_OPERAND (inner, 0);
8030                 continue;
8031               }
8032
8033             case ADDR_EXPR:
8034               inner = TREE_OPERAND (inner, 0);
8035
8036               while (REFERENCE_CLASS_P (inner)
8037                      && TREE_CODE (inner) != INDIRECT_REF)
8038                 inner = TREE_OPERAND (inner, 0);
8039
8040               if (DECL_P (inner)
8041                   && !DECL_EXTERNAL (inner)
8042                   && !TREE_STATIC (inner)
8043                   && DECL_CONTEXT (inner) == current_function_decl)
8044                 warning (0, "function returns address of local variable");
8045               break;
8046
8047             default:
8048               break;
8049             }
8050
8051           break;
8052         }
8053
8054       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
8055
8056       if (warn_sequence_point)
8057         verify_sequence_points (retval);
8058     }
8059
8060   ret_stmt = build_stmt (RETURN_EXPR, retval);
8061   TREE_NO_WARNING (ret_stmt) |= no_warning;
8062   return add_stmt (ret_stmt);
8063 }
8064 \f
8065 struct c_switch {
8066   /* The SWITCH_EXPR being built.  */
8067   tree switch_expr;
8068
8069   /* The original type of the testing expression, i.e. before the
8070      default conversion is applied.  */
8071   tree orig_type;
8072
8073   /* A splay-tree mapping the low element of a case range to the high
8074      element, or NULL_TREE if there is no high element.  Used to
8075      determine whether or not a new case label duplicates an old case
8076      label.  We need a tree, rather than simply a hash table, because
8077      of the GNU case range extension.  */
8078   splay_tree cases;
8079
8080   /* Number of nested statement expressions within this switch
8081      statement; if nonzero, case and default labels may not
8082      appear.  */
8083   unsigned int blocked_stmt_expr;
8084
8085   /* Scope of outermost declarations of identifiers with variably
8086      modified type within this switch statement; if nonzero, case and
8087      default labels may not appear.  */
8088   unsigned int blocked_vm;
8089
8090   /* The next node on the stack.  */
8091   struct c_switch *next;
8092 };
8093
8094 /* A stack of the currently active switch statements.  The innermost
8095    switch statement is on the top of the stack.  There is no need to
8096    mark the stack for garbage collection because it is only active
8097    during the processing of the body of a function, and we never
8098    collect at that point.  */
8099
8100 struct c_switch *c_switch_stack;
8101
8102 /* Start a C switch statement, testing expression EXP.  Return the new
8103    SWITCH_EXPR.  */
8104
8105 tree
8106 c_start_case (tree exp)
8107 {
8108   tree orig_type = error_mark_node;
8109   struct c_switch *cs;
8110
8111   if (exp != error_mark_node)
8112     {
8113       orig_type = TREE_TYPE (exp);
8114
8115       if (!INTEGRAL_TYPE_P (orig_type))
8116         {
8117           if (orig_type != error_mark_node)
8118             {
8119               error ("switch quantity not an integer");
8120               orig_type = error_mark_node;
8121             }
8122           exp = integer_zero_node;
8123         }
8124       else
8125         {
8126           tree type = TYPE_MAIN_VARIANT (orig_type);
8127
8128           if (!in_system_header
8129               && (type == long_integer_type_node
8130                   || type == long_unsigned_type_node))
8131             warning (OPT_Wtraditional, "%<long%> switch expression not "
8132                      "converted to %<int%> in ISO C");
8133
8134           exp = c_fully_fold (exp, false, NULL);
8135           exp = default_conversion (exp);
8136
8137           if (warn_sequence_point)
8138             verify_sequence_points (exp);
8139         }
8140     }
8141
8142   /* Add this new SWITCH_EXPR to the stack.  */
8143   cs = XNEW (struct c_switch);
8144   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
8145   cs->orig_type = orig_type;
8146   cs->cases = splay_tree_new (case_compare, NULL, NULL);
8147   cs->blocked_stmt_expr = 0;
8148   cs->blocked_vm = 0;
8149   cs->next = c_switch_stack;
8150   c_switch_stack = cs;
8151
8152   return add_stmt (cs->switch_expr);
8153 }
8154
8155 /* Process a case label.  */
8156
8157 tree
8158 do_case (tree low_value, tree high_value)
8159 {
8160   tree label = NULL_TREE;
8161
8162   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
8163     {
8164       low_value = c_fully_fold (low_value, false, NULL);
8165       if (TREE_CODE (low_value) == INTEGER_CST)
8166         pedwarn (input_location, OPT_pedantic,
8167                  "case label is not an integer constant expression");
8168     }
8169
8170   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
8171     {
8172       high_value = c_fully_fold (high_value, false, NULL);
8173       if (TREE_CODE (high_value) == INTEGER_CST)
8174         pedwarn (input_location, OPT_pedantic,
8175                  "case label is not an integer constant expression");
8176     }
8177
8178   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
8179       && !c_switch_stack->blocked_vm)
8180     {
8181       label = c_add_case_label (c_switch_stack->cases,
8182                                 SWITCH_COND (c_switch_stack->switch_expr),
8183                                 c_switch_stack->orig_type,
8184                                 low_value, high_value);
8185       if (label == error_mark_node)
8186         label = NULL_TREE;
8187     }
8188   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
8189     {
8190       if (low_value)
8191         error ("case label in statement expression not containing "
8192                "enclosing switch statement");
8193       else
8194         error ("%<default%> label in statement expression not containing "
8195                "enclosing switch statement");
8196     }
8197   else if (c_switch_stack && c_switch_stack->blocked_vm)
8198     {
8199       if (low_value)
8200         error ("case label in scope of identifier with variably modified "
8201                "type not containing enclosing switch statement");
8202       else
8203         error ("%<default%> label in scope of identifier with variably "
8204                "modified type not containing enclosing switch statement");
8205     }
8206   else if (low_value)
8207     error ("case label not within a switch statement");
8208   else
8209     error ("%<default%> label not within a switch statement");
8210
8211   return label;
8212 }
8213
8214 /* Finish the switch statement.  */
8215
8216 void
8217 c_finish_case (tree body)
8218 {
8219   struct c_switch *cs = c_switch_stack;
8220   location_t switch_location;
8221
8222   SWITCH_BODY (cs->switch_expr) = body;
8223
8224   /* We must not be within a statement expression nested in the switch
8225      at this point; we might, however, be within the scope of an
8226      identifier with variably modified type nested in the switch.  */
8227   gcc_assert (!cs->blocked_stmt_expr);
8228
8229   /* Emit warnings as needed.  */
8230   if (EXPR_HAS_LOCATION (cs->switch_expr))
8231     switch_location = EXPR_LOCATION (cs->switch_expr);
8232   else
8233     switch_location = input_location;
8234   c_do_switch_warnings (cs->cases, switch_location,
8235                         TREE_TYPE (cs->switch_expr),
8236                         SWITCH_COND (cs->switch_expr));
8237
8238   /* Pop the stack.  */
8239   c_switch_stack = cs->next;
8240   splay_tree_delete (cs->cases);
8241   XDELETE (cs);
8242 }
8243 \f
8244 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
8245    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
8246    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
8247    statement, and was not surrounded with parenthesis.  */
8248
8249 void
8250 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
8251                   tree else_block, bool nested_if)
8252 {
8253   tree stmt;
8254
8255   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
8256   if (warn_parentheses && nested_if && else_block == NULL)
8257     {
8258       tree inner_if = then_block;
8259
8260       /* We know from the grammar productions that there is an IF nested
8261          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
8262          it might not be exactly THEN_BLOCK, but should be the last
8263          non-container statement within.  */
8264       while (1)
8265         switch (TREE_CODE (inner_if))
8266           {
8267           case COND_EXPR:
8268             goto found;
8269           case BIND_EXPR:
8270             inner_if = BIND_EXPR_BODY (inner_if);
8271             break;
8272           case STATEMENT_LIST:
8273             inner_if = expr_last (then_block);
8274             break;
8275           case TRY_FINALLY_EXPR:
8276           case TRY_CATCH_EXPR:
8277             inner_if = TREE_OPERAND (inner_if, 0);
8278             break;
8279           default:
8280             gcc_unreachable ();
8281           }
8282     found:
8283
8284       if (COND_EXPR_ELSE (inner_if))
8285          warning (OPT_Wparentheses,
8286                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
8287                   &if_locus);
8288     }
8289
8290   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8291   SET_EXPR_LOCATION (stmt, if_locus);
8292   add_stmt (stmt);
8293 }
8294
8295 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8296    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8297    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8298    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8299    the continue label.  Everything is allowed to be NULL.  */
8300
8301 void
8302 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8303                tree blab, tree clab, bool cond_is_first)
8304 {
8305   tree entry = NULL, exit = NULL, t;
8306
8307   /* If the condition is zero don't generate a loop construct.  */
8308   if (cond && integer_zerop (cond))
8309     {
8310       if (cond_is_first)
8311         {
8312           t = build_and_jump (&blab);
8313           SET_EXPR_LOCATION (t, start_locus);
8314           add_stmt (t);
8315         }
8316     }
8317   else
8318     {
8319       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8320
8321       /* If we have an exit condition, then we build an IF with gotos either
8322          out of the loop, or to the top of it.  If there's no exit condition,
8323          then we just build a jump back to the top.  */
8324       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
8325
8326       if (cond && !integer_nonzerop (cond))
8327         {
8328           /* Canonicalize the loop condition to the end.  This means
8329              generating a branch to the loop condition.  Reuse the
8330              continue label, if possible.  */
8331           if (cond_is_first)
8332             {
8333               if (incr || !clab)
8334                 {
8335                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8336                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
8337                 }
8338               else
8339                 t = build1 (GOTO_EXPR, void_type_node, clab);
8340               SET_EXPR_LOCATION (t, start_locus);
8341               add_stmt (t);
8342             }
8343
8344           t = build_and_jump (&blab);
8345           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
8346           if (cond_is_first)
8347             SET_EXPR_LOCATION (exit, start_locus);
8348           else
8349             SET_EXPR_LOCATION (exit, input_location);
8350         }
8351
8352       add_stmt (top);
8353     }
8354
8355   if (body)
8356     add_stmt (body);
8357   if (clab)
8358     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
8359   if (incr)
8360     add_stmt (incr);
8361   if (entry)
8362     add_stmt (entry);
8363   if (exit)
8364     add_stmt (exit);
8365   if (blab)
8366     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
8367 }
8368
8369 tree
8370 c_finish_bc_stmt (tree *label_p, bool is_break)
8371 {
8372   bool skip;
8373   tree label = *label_p;
8374
8375   /* In switch statements break is sometimes stylistically used after
8376      a return statement.  This can lead to spurious warnings about
8377      control reaching the end of a non-void function when it is
8378      inlined.  Note that we are calling block_may_fallthru with
8379      language specific tree nodes; this works because
8380      block_may_fallthru returns true when given something it does not
8381      understand.  */
8382   skip = !block_may_fallthru (cur_stmt_list);
8383
8384   if (!label)
8385     {
8386       if (!skip)
8387         *label_p = label = create_artificial_label ();
8388     }
8389   else if (TREE_CODE (label) == LABEL_DECL)
8390     ;
8391   else switch (TREE_INT_CST_LOW (label))
8392     {
8393     case 0:
8394       if (is_break)
8395         error ("break statement not within loop or switch");
8396       else
8397         error ("continue statement not within a loop");
8398       return NULL_TREE;
8399
8400     case 1:
8401       gcc_assert (is_break);
8402       error ("break statement used with OpenMP for loop");
8403       return NULL_TREE;
8404
8405     default:
8406       gcc_unreachable ();
8407     }
8408
8409   if (skip)
8410     return NULL_TREE;
8411
8412   if (!is_break)
8413     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
8414
8415   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
8416 }
8417
8418 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
8419
8420 static void
8421 emit_side_effect_warnings (tree expr)
8422 {
8423   if (expr == error_mark_node)
8424     ;
8425   else if (!TREE_SIDE_EFFECTS (expr))
8426     {
8427       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
8428         warning (OPT_Wunused_value, "%Hstatement with no effect",
8429                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
8430     }
8431   else
8432     warn_if_unused_value (expr, input_location);
8433 }
8434
8435 /* Process an expression as if it were a complete statement.  Emit
8436    diagnostics, but do not call ADD_STMT.  */
8437
8438 tree
8439 c_process_expr_stmt (tree expr)
8440 {
8441   if (!expr)
8442     return NULL_TREE;
8443
8444   expr = c_fully_fold (expr, false, NULL);
8445
8446   if (warn_sequence_point)
8447     verify_sequence_points (expr);
8448
8449   if (TREE_TYPE (expr) != error_mark_node
8450       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
8451       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
8452     error ("expression statement has incomplete type");
8453
8454   /* If we're not processing a statement expression, warn about unused values.
8455      Warnings for statement expressions will be emitted later, once we figure
8456      out which is the result.  */
8457   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8458       && warn_unused_value)
8459     emit_side_effect_warnings (expr);
8460
8461   /* If the expression is not of a type to which we cannot assign a line
8462      number, wrap the thing in a no-op NOP_EXPR.  */
8463   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
8464     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
8465
8466   if (CAN_HAVE_LOCATION_P (expr))
8467     SET_EXPR_LOCATION (expr, input_location);
8468
8469   return expr;
8470 }
8471
8472 /* Emit an expression as a statement.  */
8473
8474 tree
8475 c_finish_expr_stmt (tree expr)
8476 {
8477   if (expr)
8478     return add_stmt (c_process_expr_stmt (expr));
8479   else
8480     return NULL;
8481 }
8482
8483 /* Do the opposite and emit a statement as an expression.  To begin,
8484    create a new binding level and return it.  */
8485
8486 tree
8487 c_begin_stmt_expr (void)
8488 {
8489   tree ret;
8490   struct c_label_context_se *nstack;
8491   struct c_label_list *glist;
8492
8493   /* We must force a BLOCK for this level so that, if it is not expanded
8494      later, there is a way to turn off the entire subtree of blocks that
8495      are contained in it.  */
8496   keep_next_level ();
8497   ret = c_begin_compound_stmt (true);
8498   if (c_switch_stack)
8499     {
8500       c_switch_stack->blocked_stmt_expr++;
8501       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
8502     }
8503   for (glist = label_context_stack_se->labels_used;
8504        glist != NULL;
8505        glist = glist->next)
8506     {
8507       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
8508     }
8509   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
8510   nstack->labels_def = NULL;
8511   nstack->labels_used = NULL;
8512   nstack->next = label_context_stack_se;
8513   label_context_stack_se = nstack;
8514
8515   /* Mark the current statement list as belonging to a statement list.  */
8516   STATEMENT_LIST_STMT_EXPR (ret) = 1;
8517
8518   return ret;
8519 }
8520
8521 tree
8522 c_finish_stmt_expr (tree body)
8523 {
8524   tree last, type, tmp, val;
8525   tree *last_p;
8526   struct c_label_list *dlist, *glist, *glist_prev = NULL;
8527
8528   body = c_end_compound_stmt (body, true);
8529   if (c_switch_stack)
8530     {
8531       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
8532       c_switch_stack->blocked_stmt_expr--;
8533     }
8534   /* It is no longer possible to jump to labels defined within this
8535      statement expression.  */
8536   for (dlist = label_context_stack_se->labels_def;
8537        dlist != NULL;
8538        dlist = dlist->next)
8539     {
8540       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
8541     }
8542   /* It is again possible to define labels with a goto just outside
8543      this statement expression.  */
8544   for (glist = label_context_stack_se->next->labels_used;
8545        glist != NULL;
8546        glist = glist->next)
8547     {
8548       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
8549       glist_prev = glist;
8550     }
8551   if (glist_prev != NULL)
8552     glist_prev->next = label_context_stack_se->labels_used;
8553   else
8554     label_context_stack_se->next->labels_used
8555       = label_context_stack_se->labels_used;
8556   label_context_stack_se = label_context_stack_se->next;
8557
8558   /* Locate the last statement in BODY.  See c_end_compound_stmt
8559      about always returning a BIND_EXPR.  */
8560   last_p = &BIND_EXPR_BODY (body);
8561   last = BIND_EXPR_BODY (body);
8562
8563  continue_searching:
8564   if (TREE_CODE (last) == STATEMENT_LIST)
8565     {
8566       tree_stmt_iterator i;
8567
8568       /* This can happen with degenerate cases like ({ }).  No value.  */
8569       if (!TREE_SIDE_EFFECTS (last))
8570         return body;
8571
8572       /* If we're supposed to generate side effects warnings, process
8573          all of the statements except the last.  */
8574       if (warn_unused_value)
8575         {
8576           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
8577             emit_side_effect_warnings (tsi_stmt (i));
8578         }
8579       else
8580         i = tsi_last (last);
8581       last_p = tsi_stmt_ptr (i);
8582       last = *last_p;
8583     }
8584
8585   /* If the end of the list is exception related, then the list was split
8586      by a call to push_cleanup.  Continue searching.  */
8587   if (TREE_CODE (last) == TRY_FINALLY_EXPR
8588       || TREE_CODE (last) == TRY_CATCH_EXPR)
8589     {
8590       last_p = &TREE_OPERAND (last, 0);
8591       last = *last_p;
8592       goto continue_searching;
8593     }
8594
8595   /* In the case that the BIND_EXPR is not necessary, return the
8596      expression out from inside it.  */
8597   if (last == error_mark_node
8598       || (last == BIND_EXPR_BODY (body)
8599           && BIND_EXPR_VARS (body) == NULL))
8600     {
8601       /* Even if this looks constant, do not allow it in a constant
8602          expression.  */
8603       last = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (last), NULL_TREE, last);
8604       C_MAYBE_CONST_EXPR_NON_CONST (last) = 1;
8605       /* Do not warn if the return value of a statement expression is
8606          unused.  */
8607       TREE_NO_WARNING (last) = 1;
8608       return last;
8609     }
8610
8611   /* Extract the type of said expression.  */
8612   type = TREE_TYPE (last);
8613
8614   /* If we're not returning a value at all, then the BIND_EXPR that
8615      we already have is a fine expression to return.  */
8616   if (!type || VOID_TYPE_P (type))
8617     return body;
8618
8619   /* Now that we've located the expression containing the value, it seems
8620      silly to make voidify_wrapper_expr repeat the process.  Create a
8621      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
8622   tmp = create_tmp_var_raw (type, NULL);
8623
8624   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
8625      tree_expr_nonnegative_p giving up immediately.  */
8626   val = last;
8627   if (TREE_CODE (val) == NOP_EXPR
8628       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
8629     val = TREE_OPERAND (val, 0);
8630
8631   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
8632   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
8633
8634   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
8635 }
8636
8637 /* Begin the scope of an identifier of variably modified type, scope
8638    number SCOPE.  Jumping from outside this scope to inside it is not
8639    permitted.  */
8640
8641 void
8642 c_begin_vm_scope (unsigned int scope)
8643 {
8644   struct c_label_context_vm *nstack;
8645   struct c_label_list *glist;
8646
8647   gcc_assert (scope > 0);
8648
8649   /* At file_scope, we don't have to do any processing.  */
8650   if (label_context_stack_vm == NULL)
8651     return;
8652
8653   if (c_switch_stack && !c_switch_stack->blocked_vm)
8654     c_switch_stack->blocked_vm = scope;
8655   for (glist = label_context_stack_vm->labels_used;
8656        glist != NULL;
8657        glist = glist->next)
8658     {
8659       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
8660     }
8661   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
8662   nstack->labels_def = NULL;
8663   nstack->labels_used = NULL;
8664   nstack->scope = scope;
8665   nstack->next = label_context_stack_vm;
8666   label_context_stack_vm = nstack;
8667 }
8668
8669 /* End a scope which may contain identifiers of variably modified
8670    type, scope number SCOPE.  */
8671
8672 void
8673 c_end_vm_scope (unsigned int scope)
8674 {
8675   if (label_context_stack_vm == NULL)
8676     return;
8677   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
8678     c_switch_stack->blocked_vm = 0;
8679   /* We may have a number of nested scopes of identifiers with
8680      variably modified type, all at this depth.  Pop each in turn.  */
8681   while (label_context_stack_vm->scope == scope)
8682     {
8683       struct c_label_list *dlist, *glist, *glist_prev = NULL;
8684
8685       /* It is no longer possible to jump to labels defined within this
8686          scope.  */
8687       for (dlist = label_context_stack_vm->labels_def;
8688            dlist != NULL;
8689            dlist = dlist->next)
8690         {
8691           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
8692         }
8693       /* It is again possible to define labels with a goto just outside
8694          this scope.  */
8695       for (glist = label_context_stack_vm->next->labels_used;
8696            glist != NULL;
8697            glist = glist->next)
8698         {
8699           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
8700           glist_prev = glist;
8701         }
8702       if (glist_prev != NULL)
8703         glist_prev->next = label_context_stack_vm->labels_used;
8704       else
8705         label_context_stack_vm->next->labels_used
8706           = label_context_stack_vm->labels_used;
8707       label_context_stack_vm = label_context_stack_vm->next;
8708     }
8709 }
8710 \f
8711 /* Begin and end compound statements.  This is as simple as pushing
8712    and popping new statement lists from the tree.  */
8713
8714 tree
8715 c_begin_compound_stmt (bool do_scope)
8716 {
8717   tree stmt = push_stmt_list ();
8718   if (do_scope)
8719     push_scope ();
8720   return stmt;
8721 }
8722
8723 tree
8724 c_end_compound_stmt (tree stmt, bool do_scope)
8725 {
8726   tree block = NULL;
8727
8728   if (do_scope)
8729     {
8730       if (c_dialect_objc ())
8731         objc_clear_super_receiver ();
8732       block = pop_scope ();
8733     }
8734
8735   stmt = pop_stmt_list (stmt);
8736   stmt = c_build_bind_expr (block, stmt);
8737
8738   /* If this compound statement is nested immediately inside a statement
8739      expression, then force a BIND_EXPR to be created.  Otherwise we'll
8740      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
8741      STATEMENT_LISTs merge, and thus we can lose track of what statement
8742      was really last.  */
8743   if (cur_stmt_list
8744       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8745       && TREE_CODE (stmt) != BIND_EXPR)
8746     {
8747       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
8748       TREE_SIDE_EFFECTS (stmt) = 1;
8749     }
8750
8751   return stmt;
8752 }
8753
8754 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
8755    when the current scope is exited.  EH_ONLY is true when this is not
8756    meant to apply to normal control flow transfer.  */
8757
8758 void
8759 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
8760 {
8761   enum tree_code code;
8762   tree stmt, list;
8763   bool stmt_expr;
8764
8765   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
8766   stmt = build_stmt (code, NULL, cleanup);
8767   add_stmt (stmt);
8768   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
8769   list = push_stmt_list ();
8770   TREE_OPERAND (stmt, 0) = list;
8771   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
8772 }
8773 \f
8774 /* Build a binary-operation expression without default conversions.
8775    CODE is the kind of expression to build.
8776    LOCATION is the operator's location.
8777    This function differs from `build' in several ways:
8778    the data type of the result is computed and recorded in it,
8779    warnings are generated if arg data types are invalid,
8780    special handling for addition and subtraction of pointers is known,
8781    and some optimization is done (operations on narrow ints
8782    are done in the narrower type when that gives the same result).
8783    Constant folding is also done before the result is returned.
8784
8785    Note that the operands will never have enumeral types, or function
8786    or array types, because either they will have the default conversions
8787    performed or they have both just been converted to some other type in which
8788    the arithmetic is to be done.  */
8789
8790 tree
8791 build_binary_op (location_t location, enum tree_code code,
8792                  tree orig_op0, tree orig_op1, int convert_p)
8793 {
8794   tree type0, type1, orig_type0, orig_type1;
8795   tree eptype;
8796   enum tree_code code0, code1;
8797   tree op0, op1;
8798   tree ret = error_mark_node;
8799   const char *invalid_op_diag;
8800   bool op0_int_operands, op1_int_operands;
8801   bool int_const, int_const_or_overflow, int_operands;
8802
8803   /* Expression code to give to the expression when it is built.
8804      Normally this is CODE, which is what the caller asked for,
8805      but in some special cases we change it.  */
8806   enum tree_code resultcode = code;
8807
8808   /* Data type in which the computation is to be performed.
8809      In the simplest cases this is the common type of the arguments.  */
8810   tree result_type = NULL;
8811
8812   /* When the computation is in excess precision, the type of the
8813      final EXCESS_PRECISION_EXPR.  */
8814   tree real_result_type = NULL;
8815
8816   /* Nonzero means operands have already been type-converted
8817      in whatever way is necessary.
8818      Zero means they need to be converted to RESULT_TYPE.  */
8819   int converted = 0;
8820
8821   /* Nonzero means create the expression with this type, rather than
8822      RESULT_TYPE.  */
8823   tree build_type = 0;
8824
8825   /* Nonzero means after finally constructing the expression
8826      convert it to this type.  */
8827   tree final_type = 0;
8828
8829   /* Nonzero if this is an operation like MIN or MAX which can
8830      safely be computed in short if both args are promoted shorts.
8831      Also implies COMMON.
8832      -1 indicates a bitwise operation; this makes a difference
8833      in the exact conditions for when it is safe to do the operation
8834      in a narrower mode.  */
8835   int shorten = 0;
8836
8837   /* Nonzero if this is a comparison operation;
8838      if both args are promoted shorts, compare the original shorts.
8839      Also implies COMMON.  */
8840   int short_compare = 0;
8841
8842   /* Nonzero if this is a right-shift operation, which can be computed on the
8843      original short and then promoted if the operand is a promoted short.  */
8844   int short_shift = 0;
8845
8846   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
8847   int common = 0;
8848
8849   /* True means types are compatible as far as ObjC is concerned.  */
8850   bool objc_ok;
8851
8852   /* True means this is an arithmetic operation that may need excess
8853      precision.  */
8854   bool may_need_excess_precision;
8855
8856   if (location == UNKNOWN_LOCATION)
8857     location = input_location;
8858
8859   op0 = orig_op0;
8860   op1 = orig_op1;
8861
8862   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
8863   if (op0_int_operands)
8864     op0 = remove_c_maybe_const_expr (op0);
8865   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
8866   if (op1_int_operands)
8867     op1 = remove_c_maybe_const_expr (op1);
8868   int_operands = (op0_int_operands && op1_int_operands);
8869   if (int_operands)
8870     {
8871       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
8872                                && TREE_CODE (orig_op1) == INTEGER_CST);
8873       int_const = (int_const_or_overflow
8874                    && !TREE_OVERFLOW (orig_op0)
8875                    && !TREE_OVERFLOW (orig_op1));
8876     }
8877   else
8878     int_const = int_const_or_overflow = false;
8879
8880   if (convert_p)
8881     {
8882       op0 = default_conversion (op0);
8883       op1 = default_conversion (op1);
8884     }
8885
8886   orig_type0 = type0 = TREE_TYPE (op0);
8887   orig_type1 = type1 = TREE_TYPE (op1);
8888
8889   /* The expression codes of the data types of the arguments tell us
8890      whether the arguments are integers, floating, pointers, etc.  */
8891   code0 = TREE_CODE (type0);
8892   code1 = TREE_CODE (type1);
8893
8894   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
8895   STRIP_TYPE_NOPS (op0);
8896   STRIP_TYPE_NOPS (op1);
8897
8898   /* If an error was already reported for one of the arguments,
8899      avoid reporting another error.  */
8900
8901   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8902     return error_mark_node;
8903
8904   if ((invalid_op_diag
8905        = targetm.invalid_binary_op (code, type0, type1)))
8906     {
8907       error_at (location, invalid_op_diag);
8908       return error_mark_node;
8909     }
8910
8911   switch (code)
8912     {
8913     case PLUS_EXPR:
8914     case MINUS_EXPR:
8915     case MULT_EXPR:
8916     case TRUNC_DIV_EXPR:
8917     case CEIL_DIV_EXPR:
8918     case FLOOR_DIV_EXPR:
8919     case ROUND_DIV_EXPR:
8920     case EXACT_DIV_EXPR:
8921       may_need_excess_precision = true;
8922       break;
8923     default:
8924       may_need_excess_precision = false;
8925       break;
8926     }
8927   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
8928     {
8929       op0 = TREE_OPERAND (op0, 0);
8930       type0 = TREE_TYPE (op0);
8931     }
8932   else if (may_need_excess_precision
8933            && (eptype = excess_precision_type (type0)) != NULL_TREE)
8934     {
8935       type0 = eptype;
8936       op0 = convert (eptype, op0);
8937     }
8938   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
8939     {
8940       op1 = TREE_OPERAND (op1, 0);
8941       type1 = TREE_TYPE (op1);
8942     }
8943   else if (may_need_excess_precision
8944            && (eptype = excess_precision_type (type1)) != NULL_TREE)
8945     {
8946       type1 = eptype;
8947       op1 = convert (eptype, op1);
8948     }
8949
8950   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8951
8952   switch (code)
8953     {
8954     case PLUS_EXPR:
8955       /* Handle the pointer + int case.  */
8956       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8957         {
8958           ret = pointer_int_sum (PLUS_EXPR, op0, op1);
8959           goto return_build_binary_op;
8960         }
8961       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8962         {
8963           ret = pointer_int_sum (PLUS_EXPR, op1, op0);
8964           goto return_build_binary_op;
8965         }
8966       else
8967         common = 1;
8968       break;
8969
8970     case MINUS_EXPR:
8971       /* Subtraction of two similar pointers.
8972          We must subtract them as integers, then divide by object size.  */
8973       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8974           && comp_target_types (type0, type1))
8975         {
8976           ret = pointer_diff (op0, op1);
8977           goto return_build_binary_op;
8978         }
8979       /* Handle pointer minus int.  Just like pointer plus int.  */
8980       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8981         {
8982           ret = pointer_int_sum (MINUS_EXPR, op0, op1);
8983           goto return_build_binary_op;
8984         }
8985       else
8986         common = 1;
8987       break;
8988
8989     case MULT_EXPR:
8990       common = 1;
8991       break;
8992
8993     case TRUNC_DIV_EXPR:
8994     case CEIL_DIV_EXPR:
8995     case FLOOR_DIV_EXPR:
8996     case ROUND_DIV_EXPR:
8997     case EXACT_DIV_EXPR:
8998       warn_for_div_by_zero (location, op1);
8999
9000       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9001            || code0 == FIXED_POINT_TYPE
9002            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9003           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9004               || code1 == FIXED_POINT_TYPE
9005               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
9006         {
9007           enum tree_code tcode0 = code0, tcode1 = code1;
9008
9009           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9010             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
9011           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
9012             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
9013
9014           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
9015               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
9016             resultcode = RDIV_EXPR;
9017           else
9018             /* Although it would be tempting to shorten always here, that
9019                loses on some targets, since the modulo instruction is
9020                undefined if the quotient can't be represented in the
9021                computation mode.  We shorten only if unsigned or if
9022                dividing by something we know != -1.  */
9023             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9024                        || (TREE_CODE (op1) == INTEGER_CST
9025                            && !integer_all_onesp (op1)));
9026           common = 1;
9027         }
9028       break;
9029
9030     case BIT_AND_EXPR:
9031     case BIT_IOR_EXPR:
9032     case BIT_XOR_EXPR:
9033       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9034         shorten = -1;
9035       /* Allow vector types which are not floating point types.   */
9036       else if (code0 == VECTOR_TYPE
9037                && code1 == VECTOR_TYPE
9038                && !VECTOR_FLOAT_TYPE_P (type0)
9039                && !VECTOR_FLOAT_TYPE_P (type1))
9040         common = 1;
9041       break;
9042
9043     case TRUNC_MOD_EXPR:
9044     case FLOOR_MOD_EXPR:
9045       warn_for_div_by_zero (location, op1);
9046
9047       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9048           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9049           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
9050         common = 1;
9051       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9052         {
9053           /* Although it would be tempting to shorten always here, that loses
9054              on some targets, since the modulo instruction is undefined if the
9055              quotient can't be represented in the computation mode.  We shorten
9056              only if unsigned or if dividing by something we know != -1.  */
9057           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9058                      || (TREE_CODE (op1) == INTEGER_CST
9059                          && !integer_all_onesp (op1)));
9060           common = 1;
9061         }
9062       break;
9063
9064     case TRUTH_ANDIF_EXPR:
9065     case TRUTH_ORIF_EXPR:
9066     case TRUTH_AND_EXPR:
9067     case TRUTH_OR_EXPR:
9068     case TRUTH_XOR_EXPR:
9069       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
9070            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9071            || code0 == FIXED_POINT_TYPE)
9072           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
9073               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9074               || code1 == FIXED_POINT_TYPE))
9075         {
9076           /* Result of these operations is always an int,
9077              but that does not mean the operands should be
9078              converted to ints!  */
9079           result_type = integer_type_node;
9080           op0 = c_common_truthvalue_conversion (location, op0);
9081           op1 = c_common_truthvalue_conversion (location, op1);
9082           converted = 1;
9083         }
9084       if (code == TRUTH_ANDIF_EXPR)
9085         {
9086           int_const_or_overflow = (int_operands
9087                                    && TREE_CODE (orig_op0) == INTEGER_CST
9088                                    && (op0 == truthvalue_false_node
9089                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9090           int_const = (int_const_or_overflow
9091                        && !TREE_OVERFLOW (orig_op0)
9092                        && (op0 == truthvalue_false_node
9093                            || !TREE_OVERFLOW (orig_op1)));
9094         }
9095       else if (code == TRUTH_ORIF_EXPR)
9096         {
9097           int_const_or_overflow = (int_operands
9098                                    && TREE_CODE (orig_op0) == INTEGER_CST
9099                                    && (op0 == truthvalue_true_node
9100                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9101           int_const = (int_const_or_overflow
9102                        && !TREE_OVERFLOW (orig_op0)
9103                        && (op0 == truthvalue_true_node
9104                            || !TREE_OVERFLOW (orig_op1)));
9105         }
9106       break;
9107
9108       /* Shift operations: result has same type as first operand;
9109          always convert second operand to int.
9110          Also set SHORT_SHIFT if shifting rightward.  */
9111
9112     case RSHIFT_EXPR:
9113       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9114           && code1 == INTEGER_TYPE)
9115         {
9116           if (TREE_CODE (op1) == INTEGER_CST)
9117             {
9118               if (tree_int_cst_sgn (op1) < 0)
9119                 {
9120                   int_const = false;
9121                   if (skip_evaluation == 0)
9122                     warning (0, "right shift count is negative");
9123                 }
9124               else
9125                 {
9126                   if (!integer_zerop (op1))
9127                     short_shift = 1;
9128
9129                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9130                     {
9131                       int_const = false;
9132                       if (skip_evaluation == 0)
9133                         warning (0, "right shift count >= width of type");
9134                     }
9135                 }
9136             }
9137
9138           /* Use the type of the value to be shifted.  */
9139           result_type = type0;
9140           /* Convert the shift-count to an integer, regardless of size
9141              of value being shifted.  */
9142           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9143             op1 = convert (integer_type_node, op1);
9144           /* Avoid converting op1 to result_type later.  */
9145           converted = 1;
9146         }
9147       break;
9148
9149     case LSHIFT_EXPR:
9150       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9151           && code1 == INTEGER_TYPE)
9152         {
9153           if (TREE_CODE (op1) == INTEGER_CST)
9154             {
9155               if (tree_int_cst_sgn (op1) < 0)
9156                 {
9157                   int_const = false;
9158                   if (skip_evaluation == 0)
9159                     warning (0, "left shift count is negative");
9160                 }
9161
9162               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9163                 {
9164                   int_const = false;
9165                   if (skip_evaluation == 0)
9166                     warning (0, "left shift count >= width of type");
9167                 }
9168             }
9169
9170           /* Use the type of the value to be shifted.  */
9171           result_type = type0;
9172           /* Convert the shift-count to an integer, regardless of size
9173              of value being shifted.  */
9174           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9175             op1 = convert (integer_type_node, op1);
9176           /* Avoid converting op1 to result_type later.  */
9177           converted = 1;
9178         }
9179       break;
9180
9181     case EQ_EXPR:
9182     case NE_EXPR:
9183       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
9184         warning_at (location,
9185                     OPT_Wfloat_equal,
9186                     "comparing floating point with == or != is unsafe");
9187       /* Result of comparison is always int,
9188          but don't convert the args to int!  */
9189       build_type = integer_type_node;
9190       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9191            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
9192           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9193               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
9194         short_compare = 1;
9195       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9196         {
9197           tree tt0 = TREE_TYPE (type0);
9198           tree tt1 = TREE_TYPE (type1);
9199           /* Anything compares with void *.  void * compares with anything.
9200              Otherwise, the targets must be compatible
9201              and both must be object or both incomplete.  */
9202           if (comp_target_types (type0, type1))
9203             result_type = common_pointer_type (type0, type1);
9204           else if (VOID_TYPE_P (tt0))
9205             {
9206               /* op0 != orig_op0 detects the case of something
9207                  whose value is 0 but which isn't a valid null ptr const.  */
9208               if (pedantic && !null_pointer_constant_p (orig_op0)
9209                   && TREE_CODE (tt1) == FUNCTION_TYPE)
9210                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9211                          "comparison of %<void *%> with function pointer");
9212             }
9213           else if (VOID_TYPE_P (tt1))
9214             {
9215               if (pedantic && !null_pointer_constant_p (orig_op1)
9216                   && TREE_CODE (tt0) == FUNCTION_TYPE)
9217                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9218                          "comparison of %<void *%> with function pointer");
9219             }
9220           else
9221             /* Avoid warning about the volatile ObjC EH puts on decls.  */
9222             if (!objc_ok)
9223               pedwarn (location, 0,
9224                        "comparison of distinct pointer types lacks a cast");
9225
9226           if (result_type == NULL_TREE)
9227             result_type = ptr_type_node;
9228         }
9229       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9230         {
9231           if (TREE_CODE (op0) == ADDR_EXPR
9232               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
9233             warning_at (location,
9234                         OPT_Waddress, "the address of %qD will never be NULL",
9235                         TREE_OPERAND (op0, 0));
9236           result_type = type0;
9237         }
9238       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9239         {
9240           if (TREE_CODE (op1) == ADDR_EXPR
9241               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
9242             warning_at (location,
9243                         OPT_Waddress, "the address of %qD will never be NULL",
9244                         TREE_OPERAND (op1, 0));
9245           result_type = type1;
9246         }
9247       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9248         {
9249           result_type = type0;
9250           pedwarn (location, 0, "comparison between pointer and integer");
9251         }
9252       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9253         {
9254           result_type = type1;
9255           pedwarn (location, 0, "comparison between pointer and integer");
9256         }
9257       break;
9258
9259     case LE_EXPR:
9260     case GE_EXPR:
9261     case LT_EXPR:
9262     case GT_EXPR:
9263       build_type = integer_type_node;
9264       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9265            || code0 == FIXED_POINT_TYPE)
9266           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9267               || code1 == FIXED_POINT_TYPE))
9268         short_compare = 1;
9269       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9270         {
9271           if (comp_target_types (type0, type1))
9272             {
9273               result_type = common_pointer_type (type0, type1);
9274               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
9275                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
9276                 pedwarn (location, 0,
9277                          "comparison of complete and incomplete pointers");
9278               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9279                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9280                          "ordered comparisons of pointers to functions");
9281             }
9282           else
9283             {
9284               result_type = ptr_type_node;
9285               pedwarn (location, 0,
9286                        "comparison of distinct pointer types lacks a cast");
9287             }
9288         }
9289       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9290         {
9291           result_type = type0;
9292           if (pedantic)
9293             pedwarn (location, OPT_pedantic,
9294                      "ordered comparison of pointer with integer zero");
9295           else if (extra_warnings)
9296             warning_at (location, OPT_Wextra,
9297                      "ordered comparison of pointer with integer zero");
9298         }
9299       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9300         {
9301           result_type = type1;
9302           pedwarn (location, OPT_pedantic,
9303                    "ordered comparison of pointer with integer zero");
9304         }
9305       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9306         {
9307           result_type = type0;
9308           pedwarn (location, 0, "comparison between pointer and integer");
9309         }
9310       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9311         {
9312           result_type = type1;
9313           pedwarn (location, 0, "comparison between pointer and integer");
9314         }
9315       break;
9316
9317     default:
9318       gcc_unreachable ();
9319     }
9320
9321   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9322     return error_mark_node;
9323
9324   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9325       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
9326           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
9327                                                     TREE_TYPE (type1))))
9328     {
9329       binary_op_error (location, code, type0, type1);
9330       return error_mark_node;
9331     }
9332
9333   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9334        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
9335       &&
9336       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9337        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
9338     {
9339       bool first_complex = (code0 == COMPLEX_TYPE);
9340       bool second_complex = (code1 == COMPLEX_TYPE);
9341       int none_complex = (!first_complex && !second_complex);
9342
9343       if (shorten || common || short_compare)
9344         {
9345           result_type = c_common_type (type0, type1);
9346           if (result_type == error_mark_node)
9347             return error_mark_node;
9348         }
9349
9350       if (first_complex != second_complex
9351           && (code == PLUS_EXPR
9352               || code == MINUS_EXPR
9353               || code == MULT_EXPR
9354               || (code == TRUNC_DIV_EXPR && first_complex))
9355           && TREE_CODE (TREE_TYPE (result_type)) == REAL_TYPE
9356           && flag_signed_zeros)
9357         {
9358           /* An operation on mixed real/complex operands must be
9359              handled specially, but the language-independent code can
9360              more easily optimize the plain complex arithmetic if
9361              -fno-signed-zeros.  */
9362           tree real_type = TREE_TYPE (result_type);
9363           tree real, imag;
9364           if (type0 != orig_type0 || type1 != orig_type1)
9365             {
9366               gcc_assert (may_need_excess_precision && common);
9367               real_result_type = c_common_type (orig_type0, orig_type1);
9368             }
9369           if (first_complex)
9370             {
9371               if (TREE_TYPE (op0) != result_type)
9372                 op0 = convert_and_check (result_type, op0);
9373               if (TREE_TYPE (op1) != real_type)
9374                 op1 = convert_and_check (real_type, op1);
9375             }
9376           else
9377             {
9378               if (TREE_TYPE (op0) != real_type)
9379                 op0 = convert_and_check (real_type, op0);
9380               if (TREE_TYPE (op1) != result_type)
9381                 op1 = convert_and_check (result_type, op1);
9382             }
9383           if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9384             return error_mark_node;
9385           if (first_complex)
9386             {
9387               op0 = c_save_expr (op0);
9388               real = build_unary_op (EXPR_LOCATION (orig_op0), REALPART_EXPR,
9389                                      op0, 1);
9390               imag = build_unary_op (EXPR_LOCATION (orig_op0), IMAGPART_EXPR,
9391                                      op0, 1);
9392               switch (code)
9393                 {
9394                 case MULT_EXPR:
9395                 case TRUNC_DIV_EXPR:
9396                   imag = build2 (resultcode, real_type, imag, op1);
9397                   /* Fall through.  */
9398                 case PLUS_EXPR:
9399                 case MINUS_EXPR:
9400                   real = build2 (resultcode, real_type, real, op1);
9401                   break;
9402                 default:
9403                   gcc_unreachable();
9404                 }
9405             }
9406           else
9407             {
9408               op1 = c_save_expr (op1);
9409               real = build_unary_op (EXPR_LOCATION (orig_op1), REALPART_EXPR,
9410                                      op1, 1);
9411               imag = build_unary_op (EXPR_LOCATION (orig_op1), IMAGPART_EXPR,
9412                                      op1, 1);
9413               switch (code)
9414                 {
9415                 case MULT_EXPR:
9416                   imag = build2 (resultcode, real_type, op0, imag);
9417                   /* Fall through.  */
9418                 case PLUS_EXPR:
9419                   real = build2 (resultcode, real_type, op0, real);
9420                   break;
9421                 case MINUS_EXPR:
9422                   real = build2 (resultcode, real_type, op0, real);
9423                   imag = build1 (NEGATE_EXPR, real_type, imag);
9424                   break;
9425                 default:
9426                   gcc_unreachable();
9427                 }
9428             }
9429           ret = build2 (COMPLEX_EXPR, result_type, real, imag);
9430           goto return_build_binary_op;
9431         }
9432
9433       /* For certain operations (which identify themselves by shorten != 0)
9434          if both args were extended from the same smaller type,
9435          do the arithmetic in that type and then extend.
9436
9437          shorten !=0 and !=1 indicates a bitwise operation.
9438          For them, this optimization is safe only if
9439          both args are zero-extended or both are sign-extended.
9440          Otherwise, we might change the result.
9441          Eg, (short)-1 | (unsigned short)-1 is (int)-1
9442          but calculated in (unsigned short) it would be (unsigned short)-1.  */
9443
9444       if (shorten && none_complex)
9445         {
9446           final_type = result_type;
9447           result_type = shorten_binary_op (result_type, op0, op1,
9448                                            shorten == -1);
9449         }
9450
9451       /* Shifts can be shortened if shifting right.  */
9452
9453       if (short_shift)
9454         {
9455           int unsigned_arg;
9456           tree arg0 = get_narrower (op0, &unsigned_arg);
9457
9458           final_type = result_type;
9459
9460           if (arg0 == op0 && final_type == TREE_TYPE (op0))
9461             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
9462
9463           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
9464               /* We can shorten only if the shift count is less than the
9465                  number of bits in the smaller type size.  */
9466               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
9467               /* We cannot drop an unsigned shift after sign-extension.  */
9468               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
9469             {
9470               /* Do an unsigned shift if the operand was zero-extended.  */
9471               result_type
9472                 = c_common_signed_or_unsigned_type (unsigned_arg,
9473                                                     TREE_TYPE (arg0));
9474               /* Convert value-to-be-shifted to that type.  */
9475               if (TREE_TYPE (op0) != result_type)
9476                 op0 = convert (result_type, op0);
9477               converted = 1;
9478             }
9479         }
9480
9481       /* Comparison operations are shortened too but differently.
9482          They identify themselves by setting short_compare = 1.  */
9483
9484       if (short_compare)
9485         {
9486           /* Don't write &op0, etc., because that would prevent op0
9487              from being kept in a register.
9488              Instead, make copies of the our local variables and
9489              pass the copies by reference, then copy them back afterward.  */
9490           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
9491           enum tree_code xresultcode = resultcode;
9492           tree val
9493             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
9494
9495           if (val != 0)
9496             {
9497               ret = val;
9498               goto return_build_binary_op;
9499             }
9500
9501           op0 = xop0, op1 = xop1;
9502           converted = 1;
9503           resultcode = xresultcode;
9504
9505           if (!skip_evaluation)
9506             {
9507               bool op0_maybe_const = true;
9508               bool op1_maybe_const = true;
9509               tree orig_op0_folded, orig_op1_folded;
9510
9511               if (in_late_binary_op)
9512                 {
9513                   orig_op0_folded = orig_op0;
9514                   orig_op1_folded = orig_op1;
9515                 }
9516               else
9517                 {
9518                   /* Fold for the sake of possible warnings, as in
9519                      build_conditional_expr.  This requires the
9520                      "original" values to be folded, not just op0 and
9521                      op1.  */
9522                   op0 = c_fully_fold (op0, require_constant_value,
9523                                       &op0_maybe_const);
9524                   op1 = c_fully_fold (op1, require_constant_value,
9525                                       &op1_maybe_const);
9526                   orig_op0_folded = c_fully_fold (orig_op0,
9527                                                   require_constant_value,
9528                                                   NULL);
9529                   orig_op1_folded = c_fully_fold (orig_op1,
9530                                                   require_constant_value,
9531                                                   NULL);
9532                 }
9533
9534               if (warn_sign_compare)
9535                 warn_for_sign_compare (location, orig_op0_folded,
9536                                        orig_op1_folded, op0, op1,
9537                                        result_type, resultcode);
9538               if (!in_late_binary_op)
9539                 {
9540                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
9541                     {
9542                       op0 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op0),
9543                                     NULL, op0);
9544                       C_MAYBE_CONST_EXPR_NON_CONST (op0) = !op0_maybe_const;
9545                     }
9546                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
9547                     {
9548                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
9549                                     NULL, op1);
9550                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
9551                     }
9552                 }
9553             }
9554         }
9555     }
9556
9557   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
9558      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
9559      Then the expression will be built.
9560      It will be given type FINAL_TYPE if that is nonzero;
9561      otherwise, it will be given type RESULT_TYPE.  */
9562
9563   if (!result_type)
9564     {
9565       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
9566       return error_mark_node;
9567     }
9568
9569   if (!converted)
9570     {
9571       if (TREE_TYPE (op0) != result_type)
9572         op0 = convert_and_check (result_type, op0);
9573       if (TREE_TYPE (op1) != result_type)
9574         op1 = convert_and_check (result_type, op1);
9575
9576       /* This can happen if one operand has a vector type, and the other
9577          has a different type.  */
9578       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9579         return error_mark_node;
9580     }
9581
9582   if (build_type == NULL_TREE)
9583     {
9584       build_type = result_type;
9585       if (type0 != orig_type0 || type1 != orig_type1)
9586         {
9587           gcc_assert (may_need_excess_precision && common);
9588           real_result_type = c_common_type (orig_type0, orig_type1);
9589         }
9590     }
9591
9592   /* Treat expressions in initializers specially as they can't trap.  */
9593   if (int_const_or_overflow)
9594     ret = (require_constant_value
9595            ? fold_build2_initializer (resultcode, build_type, op0, op1)
9596            : fold_build2 (resultcode, build_type, op0, op1));
9597   else
9598     ret = build2 (resultcode, build_type, op0, op1);
9599   if (final_type != 0)
9600     ret = convert (final_type, ret);
9601
9602  return_build_binary_op:
9603   gcc_assert (ret != error_mark_node);
9604   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
9605     ret = (int_operands
9606            ? note_integer_operands (ret)
9607            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
9608   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
9609            && !in_late_binary_op)
9610     ret = note_integer_operands (ret);
9611   if (real_result_type)
9612     ret = build1 (EXCESS_PRECISION_EXPR, real_result_type, ret);
9613   protected_set_expr_location (ret, location);
9614   return ret;
9615 }
9616
9617
9618 /* Convert EXPR to be a truth-value, validating its type for this
9619    purpose.  LOCATION is the source location for the expression.  */
9620
9621 tree
9622 c_objc_common_truthvalue_conversion (location_t location, tree expr)
9623 {
9624   bool int_const, int_operands;
9625
9626   switch (TREE_CODE (TREE_TYPE (expr)))
9627     {
9628     case ARRAY_TYPE:
9629       error_at (location, "used array that cannot be converted to pointer where scalar is required");
9630       return error_mark_node;
9631
9632     case RECORD_TYPE:
9633       error_at (location, "used struct type value where scalar is required");
9634       return error_mark_node;
9635
9636     case UNION_TYPE:
9637       error_at (location, "used union type value where scalar is required");
9638       return error_mark_node;
9639
9640     case FUNCTION_TYPE:
9641       gcc_unreachable ();
9642
9643     default:
9644       break;
9645     }
9646
9647   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
9648   int_operands = EXPR_INT_CONST_OPERANDS (expr);
9649   if (int_operands)
9650     expr = remove_c_maybe_const_expr (expr);
9651
9652   /* ??? Should we also give an error for void and vectors rather than
9653      leaving those to give errors later?  */
9654   expr = c_common_truthvalue_conversion (location, expr);
9655
9656   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
9657     {
9658       if (TREE_OVERFLOW (expr))
9659         return expr;
9660       else
9661         return note_integer_operands (expr);
9662     }
9663   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
9664     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9665   return expr;
9666 }
9667 \f
9668
9669 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
9670    required.  */
9671
9672 tree
9673 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
9674 {
9675   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
9676     {
9677       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
9678       /* Executing a compound literal inside a function reinitializes
9679          it.  */
9680       if (!TREE_STATIC (decl))
9681         *se = true;
9682       return decl;
9683     }
9684   else
9685     return expr;
9686 }
9687 \f
9688 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9689
9690 tree
9691 c_begin_omp_parallel (void)
9692 {
9693   tree block;
9694
9695   keep_next_level ();
9696   block = c_begin_compound_stmt (true);
9697
9698   return block;
9699 }
9700
9701 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
9702
9703 tree
9704 c_finish_omp_parallel (tree clauses, tree block)
9705 {
9706   tree stmt;
9707
9708   block = c_end_compound_stmt (block, true);
9709
9710   stmt = make_node (OMP_PARALLEL);
9711   TREE_TYPE (stmt) = void_type_node;
9712   OMP_PARALLEL_CLAUSES (stmt) = clauses;
9713   OMP_PARALLEL_BODY (stmt) = block;
9714
9715   return add_stmt (stmt);
9716 }
9717
9718 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9719
9720 tree
9721 c_begin_omp_task (void)
9722 {
9723   tree block;
9724
9725   keep_next_level ();
9726   block = c_begin_compound_stmt (true);
9727
9728   return block;
9729 }
9730
9731 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
9732
9733 tree
9734 c_finish_omp_task (tree clauses, tree block)
9735 {
9736   tree stmt;
9737
9738   block = c_end_compound_stmt (block, true);
9739
9740   stmt = make_node (OMP_TASK);
9741   TREE_TYPE (stmt) = void_type_node;
9742   OMP_TASK_CLAUSES (stmt) = clauses;
9743   OMP_TASK_BODY (stmt) = block;
9744
9745   return add_stmt (stmt);
9746 }
9747
9748 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
9749    Remove any elements from the list that are invalid.  */
9750
9751 tree
9752 c_finish_omp_clauses (tree clauses)
9753 {
9754   bitmap_head generic_head, firstprivate_head, lastprivate_head;
9755   tree c, t, *pc = &clauses;
9756   const char *name;
9757
9758   bitmap_obstack_initialize (NULL);
9759   bitmap_initialize (&generic_head, &bitmap_default_obstack);
9760   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
9761   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
9762
9763   for (pc = &clauses, c = clauses; c ; c = *pc)
9764     {
9765       bool remove = false;
9766       bool need_complete = false;
9767       bool need_implicitly_determined = false;
9768
9769       switch (OMP_CLAUSE_CODE (c))
9770         {
9771         case OMP_CLAUSE_SHARED:
9772           name = "shared";
9773           need_implicitly_determined = true;
9774           goto check_dup_generic;
9775
9776         case OMP_CLAUSE_PRIVATE:
9777           name = "private";
9778           need_complete = true;
9779           need_implicitly_determined = true;
9780           goto check_dup_generic;
9781
9782         case OMP_CLAUSE_REDUCTION:
9783           name = "reduction";
9784           need_implicitly_determined = true;
9785           t = OMP_CLAUSE_DECL (c);
9786           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
9787               || POINTER_TYPE_P (TREE_TYPE (t)))
9788             {
9789               error ("%qE has invalid type for %<reduction%>", t);
9790               remove = true;
9791             }
9792           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
9793             {
9794               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
9795               const char *r_name = NULL;
9796
9797               switch (r_code)
9798                 {
9799                 case PLUS_EXPR:
9800                 case MULT_EXPR:
9801                 case MINUS_EXPR:
9802                   break;
9803                 case BIT_AND_EXPR:
9804                   r_name = "&";
9805                   break;
9806                 case BIT_XOR_EXPR:
9807                   r_name = "^";
9808                   break;
9809                 case BIT_IOR_EXPR:
9810                   r_name = "|";
9811                   break;
9812                 case TRUTH_ANDIF_EXPR:
9813                   r_name = "&&";
9814                   break;
9815                 case TRUTH_ORIF_EXPR:
9816                   r_name = "||";
9817                   break;
9818                 default:
9819                   gcc_unreachable ();
9820                 }
9821               if (r_name)
9822                 {
9823                   error ("%qE has invalid type for %<reduction(%s)%>",
9824                          t, r_name);
9825                   remove = true;
9826                 }
9827             }
9828           goto check_dup_generic;
9829
9830         case OMP_CLAUSE_COPYPRIVATE:
9831           name = "copyprivate";
9832           goto check_dup_generic;
9833
9834         case OMP_CLAUSE_COPYIN:
9835           name = "copyin";
9836           t = OMP_CLAUSE_DECL (c);
9837           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
9838             {
9839               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
9840               remove = true;
9841             }
9842           goto check_dup_generic;
9843
9844         check_dup_generic:
9845           t = OMP_CLAUSE_DECL (c);
9846           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9847             {
9848               error ("%qE is not a variable in clause %qs", t, name);
9849               remove = true;
9850             }
9851           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9852                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
9853                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9854             {
9855               error ("%qE appears more than once in data clauses", t);
9856               remove = true;
9857             }
9858           else
9859             bitmap_set_bit (&generic_head, DECL_UID (t));
9860           break;
9861
9862         case OMP_CLAUSE_FIRSTPRIVATE:
9863           name = "firstprivate";
9864           t = OMP_CLAUSE_DECL (c);
9865           need_complete = true;
9866           need_implicitly_determined = true;
9867           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9868             {
9869               error ("%qE is not a variable in clause %<firstprivate%>", t);
9870               remove = true;
9871             }
9872           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9873                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
9874             {
9875               error ("%qE appears more than once in data clauses", t);
9876               remove = true;
9877             }
9878           else
9879             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
9880           break;
9881
9882         case OMP_CLAUSE_LASTPRIVATE:
9883           name = "lastprivate";
9884           t = OMP_CLAUSE_DECL (c);
9885           need_complete = true;
9886           need_implicitly_determined = true;
9887           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9888             {
9889               error ("%qE is not a variable in clause %<lastprivate%>", t);
9890               remove = true;
9891             }
9892           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9893                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9894             {
9895               error ("%qE appears more than once in data clauses", t);
9896               remove = true;
9897             }
9898           else
9899             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
9900           break;
9901
9902         case OMP_CLAUSE_IF:
9903         case OMP_CLAUSE_NUM_THREADS:
9904         case OMP_CLAUSE_SCHEDULE:
9905         case OMP_CLAUSE_NOWAIT:
9906         case OMP_CLAUSE_ORDERED:
9907         case OMP_CLAUSE_DEFAULT:
9908         case OMP_CLAUSE_UNTIED:
9909         case OMP_CLAUSE_COLLAPSE:
9910           pc = &OMP_CLAUSE_CHAIN (c);
9911           continue;
9912
9913         default:
9914           gcc_unreachable ();
9915         }
9916
9917       if (!remove)
9918         {
9919           t = OMP_CLAUSE_DECL (c);
9920
9921           if (need_complete)
9922             {
9923               t = require_complete_type (t);
9924               if (t == error_mark_node)
9925                 remove = true;
9926             }
9927
9928           if (need_implicitly_determined)
9929             {
9930               const char *share_name = NULL;
9931
9932               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
9933                 share_name = "threadprivate";
9934               else switch (c_omp_predetermined_sharing (t))
9935                 {
9936                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
9937                   break;
9938                 case OMP_CLAUSE_DEFAULT_SHARED:
9939                   share_name = "shared";
9940                   break;
9941                 case OMP_CLAUSE_DEFAULT_PRIVATE:
9942                   share_name = "private";
9943                   break;
9944                 default:
9945                   gcc_unreachable ();
9946                 }
9947               if (share_name)
9948                 {
9949                   error ("%qE is predetermined %qs for %qs",
9950                          t, share_name, name);
9951                   remove = true;
9952                 }
9953             }
9954         }
9955
9956       if (remove)
9957         *pc = OMP_CLAUSE_CHAIN (c);
9958       else
9959         pc = &OMP_CLAUSE_CHAIN (c);
9960     }
9961
9962   bitmap_obstack_release (NULL);
9963   return clauses;
9964 }
9965
9966 /* Make a variant type in the proper way for C/C++, propagating qualifiers
9967    down to the element type of an array.  */
9968
9969 tree
9970 c_build_qualified_type (tree type, int type_quals)
9971 {
9972   if (type == error_mark_node)
9973     return type;
9974
9975   if (TREE_CODE (type) == ARRAY_TYPE)
9976     {
9977       tree t;
9978       tree element_type = c_build_qualified_type (TREE_TYPE (type),
9979                                                   type_quals);
9980
9981       /* See if we already have an identically qualified type.  */
9982       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
9983         {
9984           if (TYPE_QUALS (strip_array_types (t)) == type_quals
9985               && TYPE_NAME (t) == TYPE_NAME (type)
9986               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
9987               && attribute_list_equal (TYPE_ATTRIBUTES (t),
9988                                        TYPE_ATTRIBUTES (type)))
9989             break;
9990         }
9991       if (!t)
9992         {
9993           tree domain = TYPE_DOMAIN (type);
9994
9995           t = build_variant_type_copy (type);
9996           TREE_TYPE (t) = element_type;
9997
9998           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
9999               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
10000             SET_TYPE_STRUCTURAL_EQUALITY (t);
10001           else if (TYPE_CANONICAL (element_type) != element_type
10002                    || (domain && TYPE_CANONICAL (domain) != domain))
10003             {
10004               tree unqualified_canon
10005                 = build_array_type (TYPE_CANONICAL (element_type),
10006                                     domain? TYPE_CANONICAL (domain)
10007                                           : NULL_TREE);
10008               TYPE_CANONICAL (t)
10009                 = c_build_qualified_type (unqualified_canon, type_quals);
10010             }
10011           else
10012             TYPE_CANONICAL (t) = t;
10013         }
10014       return t;
10015     }
10016
10017   /* A restrict-qualified pointer type must be a pointer to object or
10018      incomplete type.  Note that the use of POINTER_TYPE_P also allows
10019      REFERENCE_TYPEs, which is appropriate for C++.  */
10020   if ((type_quals & TYPE_QUAL_RESTRICT)
10021       && (!POINTER_TYPE_P (type)
10022           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
10023     {
10024       error ("invalid use of %<restrict%>");
10025       type_quals &= ~TYPE_QUAL_RESTRICT;
10026     }
10027
10028   return build_qualified_type (type, type_quals);
10029 }
10030
10031 /* Build a VA_ARG_EXPR for the C parser.  */
10032
10033 tree
10034 c_build_va_arg (tree expr, tree type, location_t loc)
10035 {
10036   if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
10037     warning_at (loc, OPT_Wc___compat,
10038                 "C++ requires promoted type, not enum type, in %<va_arg%>");
10039   return build_va_arg (expr, type);
10040 }