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
   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 2, 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 COPYING.  If not, write to the Free
  20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  21 02110-1301, USA.  */
  22
  23
  24 /* This file is part of the C front end.
  25    It contains routines to build C expressions given their operands,
  26    including computing the types of the result, C-specific error checks,
  27    and some optimization.  */
  28
  29 #include "config.h"
  30 #include "system.h"
  31 #include "coretypes.h"
  32 #include "tm.h"
  33 #include "rtl.h"
  34 #include "tree.h"
  35 #include "langhooks.h"
  36 #include "c-tree.h"
  37 #include "tm_p.h"
  38 #include "flags.h"
  39 #include "output.h"
  40 #include "expr.h"
  41 #include "toplev.h"
  42 #include "intl.h"
  43 #include "ggc.h"
  44 #include "target.h"
  45 #include "tree-iterator.h"
  46 #include "tree-gimple.h"
  47 #include "tree-flow.h"
  48
  49 /* Possible cases of implicit bad conversions.  Used to select
  50    diagnostic messages in convert_for_assignment.  */
  51 enum impl_conv {
  52   ic_argpass,
  53   ic_argpass_nonproto,
  54   ic_assign,
  55   ic_init,
  56   ic_return
  57 };
  58
  59 /* The level of nesting inside "__alignof__".  */
  60 int in_alignof;
  61
  62 /* The level of nesting inside "sizeof".  */
  63 int in_sizeof;
  64
  65 /* The level of nesting inside "typeof".  */
  66 int in_typeof;
  67
  68 struct c_label_context_se *label_context_stack_se;
  69 struct c_label_context_vm *label_context_stack_vm;
  70
  71 /* Nonzero if we've already printed a "missing braces around initializer"
  72    message within this initializer.  */
  73 static int missing_braces_mentioned;
  74
  75 static int require_constant_value;
  76 static int require_constant_elements;
  77
  78 static bool null_pointer_constant_p (tree);
  79 static tree qualify_type (tree, tree);
  80 static int tagged_types_tu_compatible_p (tree, tree);
  81 static int comp_target_types (tree, tree);
  82 static int function_types_compatible_p (tree, tree);
  83 static int type_lists_compatible_p (tree, tree);
  84 static tree decl_constant_value_for_broken_optimization (tree);
  85 static tree lookup_field (tree, tree);
  86 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  87 static tree pointer_diff (tree, tree);
  88 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  89                                     int);
  90 static tree valid_compound_expr_initializer (tree, tree);
  91 static void push_string (const char *);
  92 static void push_member_name (tree);
  93 static int spelling_length (void);
  94 static char *print_spelling (char *);
  95 static void warning_init (const char *);
  96 static tree digest_init (tree, tree, bool, int);
  97 static void output_init_element (tree, bool, tree, tree, int);
  98 static void output_pending_init_elements (int);
  99 static int set_designator (int);
 100 static void push_range_stack (tree);
 101 static void add_pending_init (tree, tree);
 102 static void set_nonincremental_init (void);
 103 static void set_nonincremental_init_from_string (tree);
 104 static tree find_init_member (tree);
 105 static void readonly_error (tree, enum lvalue_use);
 106 static int lvalue_or_else (tree, enum lvalue_use);
 107 static int lvalue_p (tree);
 108 static void record_maybe_used_decl (tree);
 109 static int comptypes_internal (tree, tree);
 110 \f
 111 /* Return true if EXP is a null pointer constant, false otherwise.  */
 112
 113 static bool
 114 null_pointer_constant_p (tree expr)
 115 {
 116   /* This should really operate on c_expr structures, but they aren't
 117      yet available everywhere required.  */
 118   tree type = TREE_TYPE (expr);
 119   return (TREE_CODE (expr) == INTEGER_CST
 120           && !TREE_OVERFLOW (expr)
 121           && integer_zerop (expr)
 122           && (INTEGRAL_TYPE_P (type)
 123               || (TREE_CODE (type) == POINTER_TYPE
 124                   && VOID_TYPE_P (TREE_TYPE (type))
 125                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 126 }
 127 \f/* This is a cache to hold if two types are compatible or not.  */
 128
 129 struct tagged_tu_seen_cache {
 130   const struct tagged_tu_seen_cache * next;
 131   tree t1;
 132   tree t2;
 133   /* The return value of tagged_types_tu_compatible_p if we had seen
 134      these two types already.  */
 135   int val;
 136 };
 137
 138 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 139 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 140
 141 /* Do `exp = require_complete_type (exp);' to make sure exp
 142    does not have an incomplete type.  (That includes void types.)  */
 143
 144 tree
 145 require_complete_type (tree value)
 146 {
 147   tree type = TREE_TYPE (value);
 148
 149   if (value == error_mark_node || type == error_mark_node)
 150     return error_mark_node;
 151
 152   /* First, detect a valid value with a complete type.  */
 153   if (COMPLETE_TYPE_P (type))
 154     return value;
 155
 156   c_incomplete_type_error (value, type);
 157   return error_mark_node;
 158 }
 159
 160 /* Print an error message for invalid use of an incomplete type.
 161    VALUE is the expression that was used (or 0 if that isn't known)
 162    and TYPE is the type that was invalid.  */
 163
 164 void
 165 c_incomplete_type_error (tree value, tree type)
 166 {
 167   const char *type_code_string;
 168
 169   /* Avoid duplicate error message.  */
 170   if (TREE_CODE (type) == ERROR_MARK)
 171     return;
 172
 173   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 174                      || TREE_CODE (value) == PARM_DECL))
 175     error ("%qD has an incomplete type", value);
 176   else
 177     {
 178     retry:
 179       /* We must print an error message.  Be clever about what it says.  */
 180
 181       switch (TREE_CODE (type))
 182         {
 183         case RECORD_TYPE:
 184           type_code_string = "struct";
 185           break;
 186
 187         case UNION_TYPE:
 188           type_code_string = "union";
 189           break;
 190
 191         case ENUMERAL_TYPE:
 192           type_code_string = "enum";
 193           break;
 194
 195         case VOID_TYPE:
 196           error ("invalid use of void expression");
 197           return;
 198
 199         case ARRAY_TYPE:
 200           if (TYPE_DOMAIN (type))
 201             {
 202               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 203                 {
 204                   error ("invalid use of flexible array member");
 205                   return;
 206                 }
 207               type = TREE_TYPE (type);
 208               goto retry;
 209             }
 210           error ("invalid use of array with unspecified bounds");
 211           return;
 212
 213         default:
 214           gcc_unreachable ();
 215         }
 216
 217       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 218         error ("invalid use of undefined type %<%s %E%>",
 219                type_code_string, TYPE_NAME (type));
 220       else
 221         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 222         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 223     }
 224 }
 225
 226 /* Given a type, apply default promotions wrt unnamed function
 227    arguments and return the new type.  */
 228
 229 tree
 230 c_type_promotes_to (tree type)
 231 {
 232   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 233     return double_type_node;
 234
 235   if (c_promoting_integer_type_p (type))
 236     {
 237       /* Preserve unsignedness if not really getting any wider.  */
 238       if (TYPE_UNSIGNED (type)
 239           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 240         return unsigned_type_node;
 241       return integer_type_node;
 242     }
 243
 244   return type;
 245 }
 246
 247 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 248    as well as those of TYPE.  */
 249
 250 static tree
 251 qualify_type (tree type, tree like)
 252 {
 253   return c_build_qualified_type (type,
 254                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 255 }
 256
 257 /* Return true iff the given tree T is a variable length array.  */
 258
 259 bool
 260 c_vla_type_p (tree t)
 261 {
 262   if (TREE_CODE (t) == ARRAY_TYPE
 263       && C_TYPE_VARIABLE_SIZE (t))
 264     return true;
 265   return false;
 266 }
 267 \f
 268 /* Return the composite type of two compatible types.
 269
 270    We assume that comptypes has already been done and returned
 271    nonzero; if that isn't so, this may crash.  In particular, we
 272    assume that qualifiers match.  */
 273
 274 tree
 275 composite_type (tree t1, tree t2)
 276 {
 277   enum tree_code code1;
 278   enum tree_code code2;
 279   tree attributes;
 280
 281   /* Save time if the two types are the same.  */
 282
 283   if (t1 == t2) return t1;
 284
 285   /* If one type is nonsense, use the other.  */
 286   if (t1 == error_mark_node)
 287     return t2;
 288   if (t2 == error_mark_node)
 289     return t1;
 290
 291   code1 = TREE_CODE (t1);
 292   code2 = TREE_CODE (t2);
 293
 294   /* Merge the attributes.  */
 295   attributes = targetm.merge_type_attributes (t1, t2);
 296
 297   /* If one is an enumerated type and the other is the compatible
 298      integer type, the composite type might be either of the two
 299      (DR#013 question 3).  For consistency, use the enumerated type as
 300      the composite type.  */
 301
 302   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 303     return t1;
 304   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 305     return t2;
 306
 307   gcc_assert (code1 == code2);
 308
 309   switch (code1)
 310     {
 311     case POINTER_TYPE:
 312       /* For two pointers, do this recursively on the target type.  */
 313       {
 314         tree pointed_to_1 = TREE_TYPE (t1);
 315         tree pointed_to_2 = TREE_TYPE (t2);
 316         tree target = composite_type (pointed_to_1, pointed_to_2);
 317         t1 = build_pointer_type (target);
 318         t1 = build_type_attribute_variant (t1, attributes);
 319         return qualify_type (t1, t2);
 320       }
 321
 322     case ARRAY_TYPE:
 323       {
 324         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 325         int quals;
 326         tree unqual_elt;
 327         tree d1 = TYPE_DOMAIN (t1);
 328         tree d2 = TYPE_DOMAIN (t2);
 329         bool d1_variable, d2_variable;
 330         bool d1_zero, d2_zero;
 331
 332         /* We should not have any type quals on arrays at all.  */
 333         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 334
 335         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 336         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 337
 338         d1_variable = (!d1_zero
 339                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 340                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 341         d2_variable = (!d2_zero
 342                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 343                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 344         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 345         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 346
 347         /* Save space: see if the result is identical to one of the args.  */
 348         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 349             && (d2_variable || d2_zero || !d1_variable))
 350           return build_type_attribute_variant (t1, attributes);
 351         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 352             && (d1_variable || d1_zero || !d2_variable))
 353           return build_type_attribute_variant (t2, attributes);
 354
 355         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 356           return build_type_attribute_variant (t1, attributes);
 357         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 358           return build_type_attribute_variant (t2, attributes);
 359
 360         /* Merge the element types, and have a size if either arg has
 361            one.  We may have qualifiers on the element types.  To set
 362            up TYPE_MAIN_VARIANT correctly, we need to form the
 363            composite of the unqualified types and add the qualifiers
 364            back at the end.  */
 365         quals = TYPE_QUALS (strip_array_types (elt));
 366         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 367         t1 = build_array_type (unqual_elt,
 368                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 369                                              && (d2_variable
 370                                                  || d2_zero
 371                                                  || !d1_variable))
 372                                             ? t1
 373                                             : t2));
 374         t1 = c_build_qualified_type (t1, quals);
 375         return build_type_attribute_variant (t1, attributes);
 376       }
 377
 378     case ENUMERAL_TYPE:
 379     case RECORD_TYPE:
 380     case UNION_TYPE:
 381       if (attributes != NULL)
 382         {
 383           /* Try harder not to create a new aggregate type.  */
 384           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 385             return t1;
 386           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 387             return t2;
 388         }
 389       return build_type_attribute_variant (t1, attributes);
 390
 391     case FUNCTION_TYPE:
 392       /* Function types: prefer the one that specified arg types.
 393          If both do, merge the arg types.  Also merge the return types.  */
 394       {
 395         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 396         tree p1 = TYPE_ARG_TYPES (t1);
 397         tree p2 = TYPE_ARG_TYPES (t2);
 398         int len;
 399         tree newargs, n;
 400         int i;
 401
 402         /* Save space: see if the result is identical to one of the args.  */
 403         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 404           return build_type_attribute_variant (t1, attributes);
 405         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 406           return build_type_attribute_variant (t2, attributes);
 407
 408         /* Simple way if one arg fails to specify argument types.  */
 409         if (TYPE_ARG_TYPES (t1) == 0)
 410          {
 411             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 412             t1 = build_type_attribute_variant (t1, attributes);
 413             return qualify_type (t1, t2);
 414          }
 415         if (TYPE_ARG_TYPES (t2) == 0)
 416          {
 417            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 418            t1 = build_type_attribute_variant (t1, attributes);
 419            return qualify_type (t1, t2);
 420          }
 421
 422         /* If both args specify argument types, we must merge the two
 423            lists, argument by argument.  */
 424         /* Tell global_bindings_p to return false so that variable_size
 425            doesn't die on VLAs in parameter types.  */
 426         c_override_global_bindings_to_false = true;
 427
 428         len = list_length (p1);
 429         newargs = 0;
 430
 431         for (i = 0; i < len; i++)
 432           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 433
 434         n = newargs;
 435
 436         for (; p1;
 437              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 438           {
 439             /* A null type means arg type is not specified.
 440                Take whatever the other function type has.  */
 441             if (TREE_VALUE (p1) == 0)
 442               {
 443                 TREE_VALUE (n) = TREE_VALUE (p2);
 444                 goto parm_done;
 445               }
 446             if (TREE_VALUE (p2) == 0)
 447               {
 448                 TREE_VALUE (n) = TREE_VALUE (p1);
 449                 goto parm_done;
 450               }
 451
 452             /* Given  wait (union {union wait *u; int *i} *)
 453                and  wait (union wait *),
 454                prefer  union wait *  as type of parm.  */
 455             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 456                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 457               {
 458                 tree memb;
 459                 tree mv2 = TREE_VALUE (p2);
 460                 if (mv2 && mv2 != error_mark_node
 461                     && TREE_CODE (mv2) != ARRAY_TYPE)
 462                   mv2 = TYPE_MAIN_VARIANT (mv2);
 463                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 464                      memb; memb = TREE_CHAIN (memb))
 465                   {
 466                     tree mv3 = TREE_TYPE (memb);
 467                     if (mv3 && mv3 != error_mark_node
 468                         && TREE_CODE (mv3) != ARRAY_TYPE)
 469                       mv3 = TYPE_MAIN_VARIANT (mv3);
 470                     if (comptypes (mv3, mv2))
 471                       {
 472                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 473                                                          TREE_VALUE (p2));
 474                         if (pedantic)
 475                           pedwarn ("function types not truly compatible in ISO C");
 476                         goto parm_done;
 477                       }
 478                   }
 479               }
 480             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 481                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 482               {
 483                 tree memb;
 484                 tree mv1 = TREE_VALUE (p1);
 485                 if (mv1 && mv1 != error_mark_node
 486                     && TREE_CODE (mv1) != ARRAY_TYPE)
 487                   mv1 = TYPE_MAIN_VARIANT (mv1);
 488                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 489                      memb; memb = TREE_CHAIN (memb))
 490                   {
 491                     tree mv3 = TREE_TYPE (memb);
 492                     if (mv3 && mv3 != error_mark_node
 493                         && TREE_CODE (mv3) != ARRAY_TYPE)
 494                       mv3 = TYPE_MAIN_VARIANT (mv3);
 495                     if (comptypes (mv3, mv1))
 496                       {
 497                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 498                                                          TREE_VALUE (p1));
 499                         if (pedantic)
 500                           pedwarn ("function types not truly compatible in ISO C");
 501                         goto parm_done;
 502                       }
 503                   }
 504               }
 505             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 506           parm_done: ;
 507           }
 508
 509         c_override_global_bindings_to_false = false;
 510         t1 = build_function_type (valtype, newargs);
 511         t1 = qualify_type (t1, t2);
 512         /* ... falls through ...  */
 513       }
 514
 515     default:
 516       return build_type_attribute_variant (t1, attributes);
 517     }
 518
 519 }
 520
 521 /* Return the type of a conditional expression between pointers to
 522    possibly differently qualified versions of compatible types.
 523
 524    We assume that comp_target_types has already been done and returned
 525    nonzero; if that isn't so, this may crash.  */
 526
 527 static tree
 528 common_pointer_type (tree t1, tree t2)
 529 {
 530   tree attributes;
 531   tree pointed_to_1, mv1;
 532   tree pointed_to_2, mv2;
 533   tree target;
 534
 535   /* Save time if the two types are the same.  */
 536
 537   if (t1 == t2) return t1;
 538
 539   /* If one type is nonsense, use the other.  */
 540   if (t1 == error_mark_node)
 541     return t2;
 542   if (t2 == error_mark_node)
 543     return t1;
 544
 545   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 546               && TREE_CODE (t2) == POINTER_TYPE);
 547
 548   /* Merge the attributes.  */
 549   attributes = targetm.merge_type_attributes (t1, t2);
 550
 551   /* Find the composite type of the target types, and combine the
 552      qualifiers of the two types' targets.  Do not lose qualifiers on
 553      array element types by taking the TYPE_MAIN_VARIANT.  */
 554   mv1 = pointed_to_1 = TREE_TYPE (t1);
 555   mv2 = pointed_to_2 = TREE_TYPE (t2);
 556   if (TREE_CODE (mv1) != ARRAY_TYPE)
 557     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 558   if (TREE_CODE (mv2) != ARRAY_TYPE)
 559     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 560   target = composite_type (mv1, mv2);
 561   t1 = build_pointer_type (c_build_qualified_type
 562                            (target,
 563                             TYPE_QUALS (pointed_to_1) |
 564                             TYPE_QUALS (pointed_to_2)));
 565   return build_type_attribute_variant (t1, attributes);
 566 }
 567
 568 /* Return the common type for two arithmetic types under the usual
 569    arithmetic conversions.  The default conversions have already been
 570    applied, and enumerated types converted to their compatible integer
 571    types.  The resulting type is unqualified and has no attributes.
 572
 573    This is the type for the result of most arithmetic operations
 574    if the operands have the given two types.  */
 575
 576 static tree
 577 c_common_type (tree t1, tree t2)
 578 {
 579   enum tree_code code1;
 580   enum tree_code code2;
 581
 582   /* If one type is nonsense, use the other.  */
 583   if (t1 == error_mark_node)
 584     return t2;
 585   if (t2 == error_mark_node)
 586     return t1;
 587
 588   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 589     t1 = TYPE_MAIN_VARIANT (t1);
 590
 591   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 592     t2 = TYPE_MAIN_VARIANT (t2);
 593
 594   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 595     t1 = build_type_attribute_variant (t1, NULL_TREE);
 596
 597   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 598     t2 = build_type_attribute_variant (t2, NULL_TREE);
 599
 600   /* Save time if the two types are the same.  */
 601
 602   if (t1 == t2) return t1;
 603
 604   code1 = TREE_CODE (t1);
 605   code2 = TREE_CODE (t2);
 606
 607   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 608               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 609   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 610               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 611
 612   /* When one operand is a decimal float type, the other operand cannot be
 613      a generic float type or a complex type.  We also disallow vector types
 614      here.  */
 615   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 616       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 617     {
 618       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 619         {
 620           error ("can%'t mix operands of decimal float and vector types");
 621           return error_mark_node;
 622         }
 623       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 624         {
 625           error ("can%'t mix operands of decimal float and complex types");
 626           return error_mark_node;
 627         }
 628       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 629         {
 630           error ("can%'t mix operands of decimal float and other float types");
 631           return error_mark_node;
 632         }
 633     }
 634
 635   /* If one type is a vector type, return that type.  (How the usual
 636      arithmetic conversions apply to the vector types extension is not
 637      precisely specified.)  */
 638   if (code1 == VECTOR_TYPE)
 639     return t1;
 640
 641   if (code2 == VECTOR_TYPE)
 642     return t2;
 643
 644   /* If one type is complex, form the common type of the non-complex
 645      components, then make that complex.  Use T1 or T2 if it is the
 646      required type.  */
 647   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 648     {
 649       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 650       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 651       tree subtype = c_common_type (subtype1, subtype2);
 652
 653       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 654         return t1;
 655       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 656         return t2;
 657       else
 658         return build_complex_type (subtype);
 659     }
 660
 661   /* If only one is real, use it as the result.  */
 662
 663   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 664     return t1;
 665
 666   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 667     return t2;
 668
 669   /* If both are real and either are decimal floating point types, use
 670      the decimal floating point type with the greater precision. */
 671
 672   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 673     {
 674       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 675           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 676         return dfloat128_type_node;
 677       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 678                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 679         return dfloat64_type_node;
 680       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 681                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 682         return dfloat32_type_node;
 683     }
 684
 685   /* Both real or both integers; use the one with greater precision.  */
 686
 687   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 688     return t1;
 689   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 690     return t2;
 691
 692   /* Same precision.  Prefer long longs to longs to ints when the
 693      same precision, following the C99 rules on integer type rank
 694      (which are equivalent to the C90 rules for C90 types).  */
 695
 696   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 697       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 698     return long_long_unsigned_type_node;
 699
 700   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 701       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 702     {
 703       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 704         return long_long_unsigned_type_node;
 705       else
 706         return long_long_integer_type_node;
 707     }
 708
 709   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 710       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 711     return long_unsigned_type_node;
 712
 713   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 714       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 715     {
 716       /* But preserve unsignedness from the other type,
 717          since long cannot hold all the values of an unsigned int.  */
 718       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 719         return long_unsigned_type_node;
 720       else
 721         return long_integer_type_node;
 722     }
 723
 724   /* Likewise, prefer long double to double even if same size.  */
 725   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 726       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 727     return long_double_type_node;
 728
 729   /* Otherwise prefer the unsigned one.  */
 730
 731   if (TYPE_UNSIGNED (t1))
 732     return t1;
 733   else
 734     return t2;
 735 }
 736 \f
 737 /* Wrapper around c_common_type that is used by c-common.c and other
 738    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 739    are allowed here and are converted to their compatible integer types.
 740    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 741    preferably a non-Boolean type as the common type.  */
 742 tree
 743 common_type (tree t1, tree t2)
 744 {
 745   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 746     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 747   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 748     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 749
 750   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 751   if (TREE_CODE (t1) == BOOLEAN_TYPE
 752       && TREE_CODE (t2) == BOOLEAN_TYPE)
 753     return boolean_type_node;
 754
 755   /* If either type is BOOLEAN_TYPE, then return the other.  */
 756   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 757     return t2;
 758   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 759     return t1;
 760
 761   return c_common_type (t1, t2);
 762 }
 763
 764 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 765    or various other operations.  Return 2 if they are compatible
 766    but a warning may be needed if you use them together.  */
 767
 768 int
 769 comptypes (tree type1, tree type2)
 770 {
 771   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 772   int val;
 773
 774   val = comptypes_internal (type1, type2);
 775   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 776
 777   return val;
 778 }
 779 \f
 780 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 781    or various other operations.  Return 2 if they are compatible
 782    but a warning may be needed if you use them together.  This
 783    differs from comptypes, in that we don't free the seen types.  */
 784
 785 static int
 786 comptypes_internal (tree type1, tree type2)
 787 {
 788   tree t1 = type1;
 789   tree t2 = type2;
 790   int attrval, val;
 791
 792   /* Suppress errors caused by previously reported errors.  */
 793
 794   if (t1 == t2 || !t1 || !t2
 795       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 796     return 1;
 797
 798   /* If either type is the internal version of sizetype, return the
 799      language version.  */
 800   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 801       && TYPE_ORIG_SIZE_TYPE (t1))
 802     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 803
 804   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 805       && TYPE_ORIG_SIZE_TYPE (t2))
 806     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 807
 808
 809   /* Enumerated types are compatible with integer types, but this is
 810      not transitive: two enumerated types in the same translation unit
 811      are compatible with each other only if they are the same type.  */
 812
 813   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 814     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 815   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 816     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 817
 818   if (t1 == t2)
 819     return 1;
 820
 821   /* Different classes of types can't be compatible.  */
 822
 823   if (TREE_CODE (t1) != TREE_CODE (t2))
 824     return 0;
 825
 826   /* Qualifiers must match. C99 6.7.3p9 */
 827
 828   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 829     return 0;
 830
 831   /* Allow for two different type nodes which have essentially the same
 832      definition.  Note that we already checked for equality of the type
 833      qualifiers (just above).  */
 834
 835   if (TREE_CODE (t1) != ARRAY_TYPE
 836       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 837     return 1;
 838
 839   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 840   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 841      return 0;
 842
 843   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 844   val = 0;
 845
 846   switch (TREE_CODE (t1))
 847     {
 848     case POINTER_TYPE:
 849       /* Do not remove mode or aliasing information.  */
 850       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 851           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 852         break;
 853       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 854              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 855       break;
 856
 857     case FUNCTION_TYPE:
 858       val = function_types_compatible_p (t1, t2);
 859       break;
 860
 861     case ARRAY_TYPE:
 862       {
 863         tree d1 = TYPE_DOMAIN (t1);
 864         tree d2 = TYPE_DOMAIN (t2);
 865         bool d1_variable, d2_variable;
 866         bool d1_zero, d2_zero;
 867         val = 1;
 868
 869         /* Target types must match incl. qualifiers.  */
 870         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 871             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 872           return 0;
 873
 874         /* Sizes must match unless one is missing or variable.  */
 875         if (d1 == 0 || d2 == 0 || d1 == d2)
 876           break;
 877
 878         d1_zero = !TYPE_MAX_VALUE (d1);
 879         d2_zero = !TYPE_MAX_VALUE (d2);
 880
 881         d1_variable = (!d1_zero
 882                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 883                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 884         d2_variable = (!d2_zero
 885                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 886                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 887         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 888         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 889
 890         if (d1_variable || d2_variable)
 891           break;
 892         if (d1_zero && d2_zero)
 893           break;
 894         if (d1_zero || d2_zero
 895             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 896             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 897           val = 0;
 898
 899         break;
 900       }
 901
 902     case ENUMERAL_TYPE:
 903     case RECORD_TYPE:
 904     case UNION_TYPE:
 905       if (val != 1 && !same_translation_unit_p (t1, t2))
 906         {
 907           tree a1 = TYPE_ATTRIBUTES (t1);
 908           tree a2 = TYPE_ATTRIBUTES (t2);
 909
 910           if (! attribute_list_contained (a1, a2)
 911               && ! attribute_list_contained (a2, a1))
 912             break;
 913
 914           if (attrval != 2)
 915             return tagged_types_tu_compatible_p (t1, t2);
 916           val = tagged_types_tu_compatible_p (t1, t2);
 917         }
 918       break;
 919
 920     case VECTOR_TYPE:
 921       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 922             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
 923       break;
 924
 925     default:
 926       break;
 927     }
 928   return attrval == 2 && val == 1 ? 2 : val;
 929 }
 930
 931 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 932    ignoring their qualifiers.  */
 933
 934 static int
 935 comp_target_types (tree ttl, tree ttr)
 936 {
 937   int val;
 938   tree mvl, mvr;
 939
 940   /* Do not lose qualifiers on element types of array types that are
 941      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 942   mvl = TREE_TYPE (ttl);
 943   mvr = TREE_TYPE (ttr);
 944   if (TREE_CODE (mvl) != ARRAY_TYPE)
 945     mvl = TYPE_MAIN_VARIANT (mvl);
 946   if (TREE_CODE (mvr) != ARRAY_TYPE)
 947     mvr = TYPE_MAIN_VARIANT (mvr);
 948   val = comptypes (mvl, mvr);
 949
 950   if (val == 2 && pedantic)
 951     pedwarn ("types are not quite compatible");
 952   return val;
 953 }
 954 \f
 955 /* Subroutines of `comptypes'.  */
 956
 957 /* Determine whether two trees derive from the same translation unit.
 958    If the CONTEXT chain ends in a null, that tree's context is still
 959    being parsed, so if two trees have context chains ending in null,
 960    they're in the same translation unit.  */
 961 int
 962 same_translation_unit_p (tree t1, tree t2)
 963 {
 964   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 965     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 966       {
 967       case tcc_declaration:
 968         t1 = DECL_CONTEXT (t1); break;
 969       case tcc_type:
 970         t1 = TYPE_CONTEXT (t1); break;
 971       case tcc_exceptional:
 972         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 973       default: gcc_unreachable ();
 974       }
 975
 976   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 977     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 978       {
 979       case tcc_declaration:
 980         t2 = DECL_CONTEXT (t2); break;
 981       case tcc_type:
 982         t2 = TYPE_CONTEXT (t2); break;
 983       case tcc_exceptional:
 984         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 985       default: gcc_unreachable ();
 986       }
 987
 988   return t1 == t2;
 989 }
 990
 991 /* Allocate the seen two types, assuming that they are compatible. */
 992
 993 static struct tagged_tu_seen_cache *
 994 alloc_tagged_tu_seen_cache (tree t1, tree t2)
 995 {
 996   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
 997   tu->next = tagged_tu_seen_base;
 998   tu->t1 = t1;
 999   tu->t2 = t2;
1000
1001   tagged_tu_seen_base = tu;
1002
1003   /* The C standard says that two structures in different translation
1004      units are compatible with each other only if the types of their
1005      fields are compatible (among other things).  We assume that they
1006      are compatible until proven otherwise when building the cache.
1007      An example where this can occur is:
1008      struct a
1009      {
1010        struct a *next;
1011      };
1012      If we are comparing this against a similar struct in another TU,
1013      and did not assume they were compatible, we end up with an infinite
1014      loop.  */
1015   tu->val = 1;
1016   return tu;
1017 }
1018
1019 /* Free the seen types until we get to TU_TIL. */
1020
1021 static void
1022 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1023 {
1024   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1025   while (tu != tu_til)
1026     {
1027       struct tagged_tu_seen_cache *tu1 = (struct tagged_tu_seen_cache*)tu;
1028       tu = tu1->next;
1029       free (tu1);
1030     }
1031   tagged_tu_seen_base = tu_til;
1032 }
1033
1034 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1035    compatible.  If the two types are not the same (which has been
1036    checked earlier), this can only happen when multiple translation
1037    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1038    rules.  */
1039
1040 static int
1041 tagged_types_tu_compatible_p (tree t1, tree t2)
1042 {
1043   tree s1, s2;
1044   bool needs_warning = false;
1045
1046   /* We have to verify that the tags of the types are the same.  This
1047      is harder than it looks because this may be a typedef, so we have
1048      to go look at the original type.  It may even be a typedef of a
1049      typedef...
1050      In the case of compiler-created builtin structs the TYPE_DECL
1051      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1052   while (TYPE_NAME (t1)
1053          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1054          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1055     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1056
1057   while (TYPE_NAME (t2)
1058          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1059          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1060     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1061
1062   /* C90 didn't have the requirement that the two tags be the same.  */
1063   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1064     return 0;
1065
1066   /* C90 didn't say what happened if one or both of the types were
1067      incomplete; we choose to follow C99 rules here, which is that they
1068      are compatible.  */
1069   if (TYPE_SIZE (t1) == NULL
1070       || TYPE_SIZE (t2) == NULL)
1071     return 1;
1072
1073   {
1074     const struct tagged_tu_seen_cache * tts_i;
1075     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1076       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1077         return tts_i->val;
1078   }
1079
1080   switch (TREE_CODE (t1))
1081     {
1082     case ENUMERAL_TYPE:
1083       {
1084         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1085         /* Speed up the case where the type values are in the same order.  */
1086         tree tv1 = TYPE_VALUES (t1);
1087         tree tv2 = TYPE_VALUES (t2);
1088
1089         if (tv1 == tv2)
1090           {
1091             return 1;
1092           }
1093
1094         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1095           {
1096             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1097               break;
1098             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1099               {
1100                 tu->val = 0;
1101                 return 0;
1102               }
1103           }
1104
1105         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1106           {
1107             return 1;
1108           }
1109         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1110           {
1111             tu->val = 0;
1112             return 0;
1113           }
1114
1115         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1116           {
1117             tu->val = 0;
1118             return 0;
1119           }
1120
1121         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1122           {
1123             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1124             if (s2 == NULL
1125                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1126               {
1127                 tu->val = 0;
1128                 return 0;
1129               }
1130           }
1131         return 1;
1132       }
1133
1134     case UNION_TYPE:
1135       {
1136         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1137         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1138           {
1139             tu->val = 0;
1140             return 0;
1141           }
1142
1143         /*  Speed up the common case where the fields are in the same order. */
1144         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1145              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1146           {
1147             int result;
1148
1149
1150             if (DECL_NAME (s1) == NULL
1151                 || DECL_NAME (s1) != DECL_NAME (s2))
1152               break;
1153             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1154             if (result == 0)
1155               {
1156                 tu->val = 0;
1157                 return 0;
1158               }
1159             if (result == 2)
1160               needs_warning = true;
1161
1162             if (TREE_CODE (s1) == FIELD_DECL
1163                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1164                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1165               {
1166                 tu->val = 0;
1167                 return 0;
1168               }
1169           }
1170         if (!s1 && !s2)
1171           {
1172             tu->val = needs_warning ? 2 : 1;
1173             return tu->val;
1174           }
1175
1176         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1177           {
1178             bool ok = false;
1179
1180             if (DECL_NAME (s1) != NULL)
1181               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1182                 if (DECL_NAME (s1) == DECL_NAME (s2))
1183                   {
1184                     int result;
1185                     result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1186                     if (result == 0)
1187                       {
1188                         tu->val = 0;
1189                         return 0;
1190                       }
1191                     if (result == 2)
1192                       needs_warning = true;
1193
1194                     if (TREE_CODE (s1) == FIELD_DECL
1195                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1196                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
1197                       break;
1198
1199                     ok = true;
1200                     break;
1201                   }
1202             if (!ok)
1203               {
1204                 tu->val = 0;
1205                 return 0;
1206               }
1207           }
1208         tu->val = needs_warning ? 2 : 10;
1209         return tu->val;
1210       }
1211
1212     case RECORD_TYPE:
1213       {
1214         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1215
1216         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1217              s1 && s2;
1218              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1219           {
1220             int result;
1221             if (TREE_CODE (s1) != TREE_CODE (s2)
1222                 || DECL_NAME (s1) != DECL_NAME (s2))
1223               break;
1224             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1225             if (result == 0)
1226               break;
1227             if (result == 2)
1228               needs_warning = true;
1229
1230             if (TREE_CODE (s1) == FIELD_DECL
1231                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1232                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1233               break;
1234           }
1235         if (s1 && s2)
1236           tu->val = 0;
1237         else
1238           tu->val = needs_warning ? 2 : 1;
1239         return tu->val;
1240       }
1241
1242     default:
1243       gcc_unreachable ();
1244     }
1245 }
1246
1247 /* Return 1 if two function types F1 and F2 are compatible.
1248    If either type specifies no argument types,
1249    the other must specify a fixed number of self-promoting arg types.
1250    Otherwise, if one type specifies only the number of arguments,
1251    the other must specify that number of self-promoting arg types.
1252    Otherwise, the argument types must match.  */
1253
1254 static int
1255 function_types_compatible_p (tree f1, tree f2)
1256 {
1257   tree args1, args2;
1258   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1259   int val = 1;
1260   int val1;
1261   tree ret1, ret2;
1262
1263   ret1 = TREE_TYPE (f1);
1264   ret2 = TREE_TYPE (f2);
1265
1266   /* 'volatile' qualifiers on a function's return type used to mean
1267      the function is noreturn.  */
1268   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1269     pedwarn ("function return types not compatible due to %<volatile%>");
1270   if (TYPE_VOLATILE (ret1))
1271     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1272                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1273   if (TYPE_VOLATILE (ret2))
1274     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1275                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1276   val = comptypes_internal (ret1, ret2);
1277   if (val == 0)
1278     return 0;
1279
1280   args1 = TYPE_ARG_TYPES (f1);
1281   args2 = TYPE_ARG_TYPES (f2);
1282
1283   /* An unspecified parmlist matches any specified parmlist
1284      whose argument types don't need default promotions.  */
1285
1286   if (args1 == 0)
1287     {
1288       if (!self_promoting_args_p (args2))
1289         return 0;
1290       /* If one of these types comes from a non-prototype fn definition,
1291          compare that with the other type's arglist.
1292          If they don't match, ask for a warning (but no error).  */
1293       if (TYPE_ACTUAL_ARG_TYPES (f1)
1294           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1295         val = 2;
1296       return val;
1297     }
1298   if (args2 == 0)
1299     {
1300       if (!self_promoting_args_p (args1))
1301         return 0;
1302       if (TYPE_ACTUAL_ARG_TYPES (f2)
1303           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1304         val = 2;
1305       return val;
1306     }
1307
1308   /* Both types have argument lists: compare them and propagate results.  */
1309   val1 = type_lists_compatible_p (args1, args2);
1310   return val1 != 1 ? val1 : val;
1311 }
1312
1313 /* Check two lists of types for compatibility,
1314    returning 0 for incompatible, 1 for compatible,
1315    or 2 for compatible with warning.  */
1316
1317 static int
1318 type_lists_compatible_p (tree args1, tree args2)
1319 {
1320   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1321   int val = 1;
1322   int newval = 0;
1323
1324   while (1)
1325     {
1326       tree a1, mv1, a2, mv2;
1327       if (args1 == 0 && args2 == 0)
1328         return val;
1329       /* If one list is shorter than the other,
1330          they fail to match.  */
1331       if (args1 == 0 || args2 == 0)
1332         return 0;
1333       mv1 = a1 = TREE_VALUE (args1);
1334       mv2 = a2 = TREE_VALUE (args2);
1335       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1336         mv1 = TYPE_MAIN_VARIANT (mv1);
1337       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1338         mv2 = TYPE_MAIN_VARIANT (mv2);
1339       /* A null pointer instead of a type
1340          means there is supposed to be an argument
1341          but nothing is specified about what type it has.
1342          So match anything that self-promotes.  */
1343       if (a1 == 0)
1344         {
1345           if (c_type_promotes_to (a2) != a2)
1346             return 0;
1347         }
1348       else if (a2 == 0)
1349         {
1350           if (c_type_promotes_to (a1) != a1)
1351             return 0;
1352         }
1353       /* If one of the lists has an error marker, ignore this arg.  */
1354       else if (TREE_CODE (a1) == ERROR_MARK
1355                || TREE_CODE (a2) == ERROR_MARK)
1356         ;
1357       else if (!(newval = comptypes_internal (mv1, mv2)))
1358         {
1359           /* Allow  wait (union {union wait *u; int *i} *)
1360              and  wait (union wait *)  to be compatible.  */
1361           if (TREE_CODE (a1) == UNION_TYPE
1362               && (TYPE_NAME (a1) == 0
1363                   || TYPE_TRANSPARENT_UNION (a1))
1364               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1365               && tree_int_cst_equal (TYPE_SIZE (a1),
1366                                      TYPE_SIZE (a2)))
1367             {
1368               tree memb;
1369               for (memb = TYPE_FIELDS (a1);
1370                    memb; memb = TREE_CHAIN (memb))
1371                 {
1372                   tree mv3 = TREE_TYPE (memb);
1373                   if (mv3 && mv3 != error_mark_node
1374                       && TREE_CODE (mv3) != ARRAY_TYPE)
1375                     mv3 = TYPE_MAIN_VARIANT (mv3);
1376                   if (comptypes_internal (mv3, mv2))
1377                     break;
1378                 }
1379               if (memb == 0)
1380                 return 0;
1381             }
1382           else if (TREE_CODE (a2) == UNION_TYPE
1383                    && (TYPE_NAME (a2) == 0
1384                        || TYPE_TRANSPARENT_UNION (a2))
1385                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1386                    && tree_int_cst_equal (TYPE_SIZE (a2),
1387                                           TYPE_SIZE (a1)))
1388             {
1389               tree memb;
1390               for (memb = TYPE_FIELDS (a2);
1391                    memb; memb = TREE_CHAIN (memb))
1392                 {
1393                   tree mv3 = TREE_TYPE (memb);
1394                   if (mv3 && mv3 != error_mark_node
1395                       && TREE_CODE (mv3) != ARRAY_TYPE)
1396                     mv3 = TYPE_MAIN_VARIANT (mv3);
1397                   if (comptypes_internal (mv3, mv1))
1398                     break;
1399                 }
1400               if (memb == 0)
1401                 return 0;
1402             }
1403           else
1404             return 0;
1405         }
1406
1407       /* comptypes said ok, but record if it said to warn.  */
1408       if (newval > val)
1409         val = newval;
1410
1411       args1 = TREE_CHAIN (args1);
1412       args2 = TREE_CHAIN (args2);
1413     }
1414 }
1415 \f
1416 /* Compute the size to increment a pointer by.  */
1417
1418 static tree
1419 c_size_in_bytes (tree type)
1420 {
1421   enum tree_code code = TREE_CODE (type);
1422
1423   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1424     return size_one_node;
1425
1426   if (!COMPLETE_OR_VOID_TYPE_P (type))
1427     {
1428       error ("arithmetic on pointer to an incomplete type");
1429       return size_one_node;
1430     }
1431
1432   /* Convert in case a char is more than one unit.  */
1433   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1434                      size_int (TYPE_PRECISION (char_type_node)
1435                                / BITS_PER_UNIT));
1436 }
1437 \f
1438 /* Return either DECL or its known constant value (if it has one).  */
1439
1440 tree
1441 decl_constant_value (tree decl)
1442 {
1443   if (/* Don't change a variable array bound or initial value to a constant
1444          in a place where a variable is invalid.  Note that DECL_INITIAL
1445          isn't valid for a PARM_DECL.  */
1446       current_function_decl != 0
1447       && TREE_CODE (decl) != PARM_DECL
1448       && !TREE_THIS_VOLATILE (decl)
1449       && TREE_READONLY (decl)
1450       && DECL_INITIAL (decl) != 0
1451       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1452       /* This is invalid if initial value is not constant.
1453          If it has either a function call, a memory reference,
1454          or a variable, then re-evaluating it could give different results.  */
1455       && TREE_CONSTANT (DECL_INITIAL (decl))
1456       /* Check for cases where this is sub-optimal, even though valid.  */
1457       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1458     return DECL_INITIAL (decl);
1459   return decl;
1460 }
1461
1462 /* Return either DECL or its known constant value (if it has one), but
1463    return DECL if pedantic or DECL has mode BLKmode.  This is for
1464    bug-compatibility with the old behavior of decl_constant_value
1465    (before GCC 3.0); every use of this function is a bug and it should
1466    be removed before GCC 3.1.  It is not appropriate to use pedantic
1467    in a way that affects optimization, and BLKmode is probably not the
1468    right test for avoiding misoptimizations either.  */
1469
1470 static tree
1471 decl_constant_value_for_broken_optimization (tree decl)
1472 {
1473   tree ret;
1474
1475   if (pedantic || DECL_MODE (decl) == BLKmode)
1476     return decl;
1477
1478   ret = decl_constant_value (decl);
1479   /* Avoid unwanted tree sharing between the initializer and current
1480      function's body where the tree can be modified e.g. by the
1481      gimplifier.  */
1482   if (ret != decl && TREE_STATIC (decl))
1483     ret = unshare_expr (ret);
1484   return ret;
1485 }
1486
1487 /* Convert the array expression EXP to a pointer.  */
1488 static tree
1489 array_to_pointer_conversion (tree exp)
1490 {
1491   tree orig_exp = exp;
1492   tree type = TREE_TYPE (exp);
1493   tree adr;
1494   tree restype = TREE_TYPE (type);
1495   tree ptrtype;
1496
1497   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1498
1499   STRIP_TYPE_NOPS (exp);
1500
1501   if (TREE_NO_WARNING (orig_exp))
1502     TREE_NO_WARNING (exp) = 1;
1503
1504   ptrtype = build_pointer_type (restype);
1505
1506   if (TREE_CODE (exp) == INDIRECT_REF)
1507     return convert (ptrtype, TREE_OPERAND (exp, 0));
1508
1509   if (TREE_CODE (exp) == VAR_DECL)
1510     {
1511       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1512          ADDR_EXPR because it's the best way of representing what
1513          happens in C when we take the address of an array and place
1514          it in a pointer to the element type.  */
1515       adr = build1 (ADDR_EXPR, ptrtype, exp);
1516       if (!c_mark_addressable (exp))
1517         return error_mark_node;
1518       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1519       return adr;
1520     }
1521
1522   /* This way is better for a COMPONENT_REF since it can
1523      simplify the offset for a component.  */
1524   adr = build_unary_op (ADDR_EXPR, exp, 1);
1525   return convert (ptrtype, adr);
1526 }
1527
1528 /* Convert the function expression EXP to a pointer.  */
1529 static tree
1530 function_to_pointer_conversion (tree exp)
1531 {
1532   tree orig_exp = exp;
1533
1534   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1535
1536   STRIP_TYPE_NOPS (exp);
1537
1538   if (TREE_NO_WARNING (orig_exp))
1539     TREE_NO_WARNING (exp) = 1;
1540
1541   return build_unary_op (ADDR_EXPR, exp, 0);
1542 }
1543
1544 /* Perform the default conversion of arrays and functions to pointers.
1545    Return the result of converting EXP.  For any other expression, just
1546    return EXP after removing NOPs.  */
1547
1548 struct c_expr
1549 default_function_array_conversion (struct c_expr exp)
1550 {
1551   tree orig_exp = exp.value;
1552   tree type = TREE_TYPE (exp.value);
1553   enum tree_code code = TREE_CODE (type);
1554
1555   switch (code)
1556     {
1557     case ARRAY_TYPE:
1558       {
1559         bool not_lvalue = false;
1560         bool lvalue_array_p;
1561
1562         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1563                 || TREE_CODE (exp.value) == NOP_EXPR
1564                 || TREE_CODE (exp.value) == CONVERT_EXPR)
1565                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1566           {
1567             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1568               not_lvalue = true;
1569             exp.value = TREE_OPERAND (exp.value, 0);
1570           }
1571
1572         if (TREE_NO_WARNING (orig_exp))
1573           TREE_NO_WARNING (exp.value) = 1;
1574
1575         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1576         if (!flag_isoc99 && !lvalue_array_p)
1577           {
1578             /* Before C99, non-lvalue arrays do not decay to pointers.
1579                Normally, using such an array would be invalid; but it can
1580                be used correctly inside sizeof or as a statement expression.
1581                Thus, do not give an error here; an error will result later.  */
1582             return exp;
1583           }
1584
1585         exp.value = array_to_pointer_conversion (exp.value);
1586       }
1587       break;
1588     case FUNCTION_TYPE:
1589       exp.value = function_to_pointer_conversion (exp.value);
1590       break;
1591     default:
1592       STRIP_TYPE_NOPS (exp.value);
1593       if (TREE_NO_WARNING (orig_exp))
1594         TREE_NO_WARNING (exp.value) = 1;
1595       break;
1596     }
1597
1598   return exp;
1599 }
1600
1601
1602 /* EXP is an expression of integer type.  Apply the integer promotions
1603    to it and return the promoted value.  */
1604
1605 tree
1606 perform_integral_promotions (tree exp)
1607 {
1608   tree type = TREE_TYPE (exp);
1609   enum tree_code code = TREE_CODE (type);
1610
1611   gcc_assert (INTEGRAL_TYPE_P (type));
1612
1613   /* Normally convert enums to int,
1614      but convert wide enums to something wider.  */
1615   if (code == ENUMERAL_TYPE)
1616     {
1617       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1618                                           TYPE_PRECISION (integer_type_node)),
1619                                      ((TYPE_PRECISION (type)
1620                                        >= TYPE_PRECISION (integer_type_node))
1621                                       && TYPE_UNSIGNED (type)));
1622
1623       return convert (type, exp);
1624     }
1625
1626   /* ??? This should no longer be needed now bit-fields have their
1627      proper types.  */
1628   if (TREE_CODE (exp) == COMPONENT_REF
1629       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1630       /* If it's thinner than an int, promote it like a
1631          c_promoting_integer_type_p, otherwise leave it alone.  */
1632       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1633                                TYPE_PRECISION (integer_type_node)))
1634     return convert (integer_type_node, exp);
1635
1636   if (c_promoting_integer_type_p (type))
1637     {
1638       /* Preserve unsignedness if not really getting any wider.  */
1639       if (TYPE_UNSIGNED (type)
1640           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1641         return convert (unsigned_type_node, exp);
1642
1643       return convert (integer_type_node, exp);
1644     }
1645
1646   return exp;
1647 }
1648
1649
1650 /* Perform default promotions for C data used in expressions.
1651    Enumeral types or short or char are converted to int.
1652    In addition, manifest constants symbols are replaced by their values.  */
1653
1654 tree
1655 default_conversion (tree exp)
1656 {
1657   tree orig_exp;
1658   tree type = TREE_TYPE (exp);
1659   enum tree_code code = TREE_CODE (type);
1660
1661   /* Functions and arrays have been converted during parsing.  */
1662   gcc_assert (code != FUNCTION_TYPE);
1663   if (code == ARRAY_TYPE)
1664     return exp;
1665
1666   /* Constants can be used directly unless they're not loadable.  */
1667   if (TREE_CODE (exp) == CONST_DECL)
1668     exp = DECL_INITIAL (exp);
1669
1670   /* Replace a nonvolatile const static variable with its value unless
1671      it is an array, in which case we must be sure that taking the
1672      address of the array produces consistent results.  */
1673   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1674     {
1675       exp = decl_constant_value_for_broken_optimization (exp);
1676       type = TREE_TYPE (exp);
1677     }
1678
1679   /* Strip no-op conversions.  */
1680   orig_exp = exp;
1681   STRIP_TYPE_NOPS (exp);
1682
1683   if (TREE_NO_WARNING (orig_exp))
1684     TREE_NO_WARNING (exp) = 1;
1685
1686   if (INTEGRAL_TYPE_P (type))
1687     return perform_integral_promotions (exp);
1688
1689   if (code == VOID_TYPE)
1690     {
1691       error ("void value not ignored as it ought to be");
1692       return error_mark_node;
1693     }
1694   return exp;
1695 }
1696 \f
1697 /* Look up COMPONENT in a structure or union DECL.
1698
1699    If the component name is not found, returns NULL_TREE.  Otherwise,
1700    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1701    stepping down the chain to the component, which is in the last
1702    TREE_VALUE of the list.  Normally the list is of length one, but if
1703    the component is embedded within (nested) anonymous structures or
1704    unions, the list steps down the chain to the component.  */
1705
1706 static tree
1707 lookup_field (tree decl, tree component)
1708 {
1709   tree type = TREE_TYPE (decl);
1710   tree field;
1711
1712   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1713      to the field elements.  Use a binary search on this array to quickly
1714      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1715      will always be set for structures which have many elements.  */
1716
1717   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1718     {
1719       int bot, top, half;
1720       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1721
1722       field = TYPE_FIELDS (type);
1723       bot = 0;
1724       top = TYPE_LANG_SPECIFIC (type)->s->len;
1725       while (top - bot > 1)
1726         {
1727           half = (top - bot + 1) >> 1;
1728           field = field_array[bot+half];
1729
1730           if (DECL_NAME (field) == NULL_TREE)
1731             {
1732               /* Step through all anon unions in linear fashion.  */
1733               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1734                 {
1735                   field = field_array[bot++];
1736                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1737                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1738                     {
1739                       tree anon = lookup_field (field, component);
1740
1741                       if (anon)
1742                         return tree_cons (NULL_TREE, field, anon);
1743                     }
1744                 }
1745
1746               /* Entire record is only anon unions.  */
1747               if (bot > top)
1748                 return NULL_TREE;
1749
1750               /* Restart the binary search, with new lower bound.  */
1751               continue;
1752             }
1753
1754           if (DECL_NAME (field) == component)
1755             break;
1756           if (DECL_NAME (field) < component)
1757             bot += half;
1758           else
1759             top = bot + half;
1760         }
1761
1762       if (DECL_NAME (field_array[bot]) == component)
1763         field = field_array[bot];
1764       else if (DECL_NAME (field) != component)
1765         return NULL_TREE;
1766     }
1767   else
1768     {
1769       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1770         {
1771           if (DECL_NAME (field) == NULL_TREE
1772               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1773                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1774             {
1775               tree anon = lookup_field (field, component);
1776
1777               if (anon)
1778                 return tree_cons (NULL_TREE, field, anon);
1779             }
1780
1781           if (DECL_NAME (field) == component)
1782             break;
1783         }
1784
1785       if (field == NULL_TREE)
1786         return NULL_TREE;
1787     }
1788
1789   return tree_cons (NULL_TREE, field, NULL_TREE);
1790 }
1791
1792 /* Make an expression to refer to the COMPONENT field of
1793    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1794
1795 tree
1796 build_component_ref (tree datum, tree component)
1797 {
1798   tree type = TREE_TYPE (datum);
1799   enum tree_code code = TREE_CODE (type);
1800   tree field = NULL;
1801   tree ref;
1802
1803   if (!objc_is_public (datum, component))
1804     return error_mark_node;
1805
1806   /* See if there is a field or component with name COMPONENT.  */
1807
1808   if (code == RECORD_TYPE || code == UNION_TYPE)
1809     {
1810       if (!COMPLETE_TYPE_P (type))
1811         {
1812           c_incomplete_type_error (NULL_TREE, type);
1813           return error_mark_node;
1814         }
1815
1816       field = lookup_field (datum, component);
1817
1818       if (!field)
1819         {
1820           error ("%qT has no member named %qE", type, component);
1821           return error_mark_node;
1822         }
1823
1824       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1825          This might be better solved in future the way the C++ front
1826          end does it - by giving the anonymous entities each a
1827          separate name and type, and then have build_component_ref
1828          recursively call itself.  We can't do that here.  */
1829       do
1830         {
1831           tree subdatum = TREE_VALUE (field);
1832           int quals;
1833           tree subtype;
1834
1835           if (TREE_TYPE (subdatum) == error_mark_node)
1836             return error_mark_node;
1837
1838           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1839           quals |= TYPE_QUALS (TREE_TYPE (datum));
1840           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1841
1842           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1843                         NULL_TREE);
1844           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1845             TREE_READONLY (ref) = 1;
1846           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1847             TREE_THIS_VOLATILE (ref) = 1;
1848
1849           if (TREE_DEPRECATED (subdatum))
1850             warn_deprecated_use (subdatum);
1851
1852           datum = ref;
1853
1854           field = TREE_CHAIN (field);
1855         }
1856       while (field);
1857
1858       return ref;
1859     }
1860   else if (code != ERROR_MARK)
1861     error ("request for member %qE in something not a structure or union",
1862            component);
1863
1864   return error_mark_node;
1865 }
1866 \f
1867 /* Given an expression PTR for a pointer, return an expression
1868    for the value pointed to.
1869    ERRORSTRING is the name of the operator to appear in error messages.  */
1870
1871 tree
1872 build_indirect_ref (tree ptr, const char *errorstring)
1873 {
1874   tree pointer = default_conversion (ptr);
1875   tree type = TREE_TYPE (pointer);
1876
1877   if (TREE_CODE (type) == POINTER_TYPE)
1878     {
1879       if (TREE_CODE (pointer) == ADDR_EXPR
1880           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1881               == TREE_TYPE (type)))
1882         return TREE_OPERAND (pointer, 0);
1883       else
1884         {
1885           tree t = TREE_TYPE (type);
1886           tree ref;
1887
1888           ref = build1 (INDIRECT_REF, t, pointer);
1889
1890           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1891             {
1892               error ("dereferencing pointer to incomplete type");
1893               return error_mark_node;
1894             }
1895           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1896             warning (0, "dereferencing %<void *%> pointer");
1897
1898           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1899              so that we get the proper error message if the result is used
1900              to assign to.  Also, &* is supposed to be a no-op.
1901              And ANSI C seems to specify that the type of the result
1902              should be the const type.  */
1903           /* A de-reference of a pointer to const is not a const.  It is valid
1904              to change it via some other pointer.  */
1905           TREE_READONLY (ref) = TYPE_READONLY (t);
1906           TREE_SIDE_EFFECTS (ref)
1907             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1908           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1909           return ref;
1910         }
1911     }
1912   else if (TREE_CODE (pointer) != ERROR_MARK)
1913     error ("invalid type argument of %qs", errorstring);
1914   return error_mark_node;
1915 }
1916
1917 /* This handles expressions of the form "a[i]", which denotes
1918    an array reference.
1919
1920    This is logically equivalent in C to *(a+i), but we may do it differently.
1921    If A is a variable or a member, we generate a primitive ARRAY_REF.
1922    This avoids forcing the array out of registers, and can work on
1923    arrays that are not lvalues (for example, members of structures returned
1924    by functions).  */
1925
1926 tree
1927 build_array_ref (tree array, tree index)
1928 {
1929   bool swapped = false;
1930   if (TREE_TYPE (array) == error_mark_node
1931       || TREE_TYPE (index) == error_mark_node)
1932     return error_mark_node;
1933
1934   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1935       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1936     {
1937       tree temp;
1938       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1939           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1940         {
1941           error ("subscripted value is neither array nor pointer");
1942           return error_mark_node;
1943         }
1944       temp = array;
1945       array = index;
1946       index = temp;
1947       swapped = true;
1948     }
1949
1950   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1951     {
1952       error ("array subscript is not an integer");
1953       return error_mark_node;
1954     }
1955
1956   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1957     {
1958       error ("subscripted value is pointer to function");
1959       return error_mark_node;
1960     }
1961
1962   /* ??? Existing practice has been to warn only when the char
1963      index is syntactically the index, not for char[array].  */
1964   if (!swapped)
1965      warn_array_subscript_with_type_char (index);
1966
1967   /* Apply default promotions *after* noticing character types.  */
1968   index = default_conversion (index);
1969
1970   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1971
1972   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1973     {
1974       tree rval, type;
1975
1976       /* An array that is indexed by a non-constant
1977          cannot be stored in a register; we must be able to do
1978          address arithmetic on its address.
1979          Likewise an array of elements of variable size.  */
1980       if (TREE_CODE (index) != INTEGER_CST
1981           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1982               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1983         {
1984           if (!c_mark_addressable (array))
1985             return error_mark_node;
1986         }
1987       /* An array that is indexed by a constant value which is not within
1988          the array bounds cannot be stored in a register either; because we
1989          would get a crash in store_bit_field/extract_bit_field when trying
1990          to access a non-existent part of the register.  */
1991       if (TREE_CODE (index) == INTEGER_CST
1992           && TYPE_DOMAIN (TREE_TYPE (array))
1993           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1994         {
1995           if (!c_mark_addressable (array))
1996             return error_mark_node;
1997         }
1998
1999       if (pedantic)
2000         {
2001           tree foo = array;
2002           while (TREE_CODE (foo) == COMPONENT_REF)
2003             foo = TREE_OPERAND (foo, 0);
2004           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2005             pedwarn ("ISO C forbids subscripting %<register%> array");
2006           else if (!flag_isoc99 && !lvalue_p (foo))
2007             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
2008         }
2009
2010       type = TREE_TYPE (TREE_TYPE (array));
2011       if (TREE_CODE (type) != ARRAY_TYPE)
2012         type = TYPE_MAIN_VARIANT (type);
2013       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2014       /* Array ref is const/volatile if the array elements are
2015          or if the array is.  */
2016       TREE_READONLY (rval)
2017         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2018             | TREE_READONLY (array));
2019       TREE_SIDE_EFFECTS (rval)
2020         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2021             | TREE_SIDE_EFFECTS (array));
2022       TREE_THIS_VOLATILE (rval)
2023         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2024             /* This was added by rms on 16 Nov 91.
2025                It fixes  vol struct foo *a;  a->elts[1]
2026                in an inline function.
2027                Hope it doesn't break something else.  */
2028             | TREE_THIS_VOLATILE (array));
2029       return require_complete_type (fold (rval));
2030     }
2031   else
2032     {
2033       tree ar = default_conversion (array);
2034
2035       if (ar == error_mark_node)
2036         return ar;
2037
2038       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2039       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2040
2041       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
2042                                  "array indexing");
2043     }
2044 }
2045 \f
2046 /* Build an external reference to identifier ID.  FUN indicates
2047    whether this will be used for a function call.  LOC is the source
2048    location of the identifier.  */
2049 tree
2050 build_external_ref (tree id, int fun, location_t loc)
2051 {
2052   tree ref;
2053   tree decl = lookup_name (id);
2054
2055   /* In Objective-C, an instance variable (ivar) may be preferred to
2056      whatever lookup_name() found.  */
2057   decl = objc_lookup_ivar (decl, id);
2058
2059   if (decl && decl != error_mark_node)
2060     ref = decl;
2061   else if (fun)
2062     /* Implicit function declaration.  */
2063     ref = implicitly_declare (id);
2064   else if (decl == error_mark_node)
2065     /* Don't complain about something that's already been
2066        complained about.  */
2067     return error_mark_node;
2068   else
2069     {
2070       undeclared_variable (id, loc);
2071       return error_mark_node;
2072     }
2073
2074   if (TREE_TYPE (ref) == error_mark_node)
2075     return error_mark_node;
2076
2077   if (TREE_DEPRECATED (ref))
2078     warn_deprecated_use (ref);
2079
2080   if (!skip_evaluation)
2081     assemble_external (ref);
2082   TREE_USED (ref) = 1;
2083
2084   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2085     {
2086       if (!in_sizeof && !in_typeof)
2087         C_DECL_USED (ref) = 1;
2088       else if (DECL_INITIAL (ref) == 0
2089                && DECL_EXTERNAL (ref)
2090                && !TREE_PUBLIC (ref))
2091         record_maybe_used_decl (ref);
2092     }
2093
2094   if (TREE_CODE (ref) == CONST_DECL)
2095     {
2096       used_types_insert (TREE_TYPE (ref));
2097       ref = DECL_INITIAL (ref);
2098       TREE_CONSTANT (ref) = 1;
2099       TREE_INVARIANT (ref) = 1;
2100     }
2101   else if (current_function_decl != 0
2102            && !DECL_FILE_SCOPE_P (current_function_decl)
2103            && (TREE_CODE (ref) == VAR_DECL
2104                || TREE_CODE (ref) == PARM_DECL
2105                || TREE_CODE (ref) == FUNCTION_DECL))
2106     {
2107       tree context = decl_function_context (ref);
2108
2109       if (context != 0 && context != current_function_decl)
2110         DECL_NONLOCAL (ref) = 1;
2111     }
2112   /* C99 6.7.4p3: An inline definition of a function with external
2113      linkage ... shall not contain a reference to an identifier with
2114      internal linkage.  */
2115   else if (current_function_decl != 0
2116            && DECL_DECLARED_INLINE_P (current_function_decl)
2117            && DECL_EXTERNAL (current_function_decl)
2118            && VAR_OR_FUNCTION_DECL_P (ref)
2119            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2120            && ! TREE_PUBLIC (ref))
2121     pedwarn ("%H%qD is static but used in inline function %qD "
2122              "which is not static", &loc, ref, current_function_decl);
2123
2124   return ref;
2125 }
2126
2127 /* Record details of decls possibly used inside sizeof or typeof.  */
2128 struct maybe_used_decl
2129 {
2130   /* The decl.  */
2131   tree decl;
2132   /* The level seen at (in_sizeof + in_typeof).  */
2133   int level;
2134   /* The next one at this level or above, or NULL.  */
2135   struct maybe_used_decl *next;
2136 };
2137
2138 static struct maybe_used_decl *maybe_used_decls;
2139
2140 /* Record that DECL, an undefined static function reference seen
2141    inside sizeof or typeof, might be used if the operand of sizeof is
2142    a VLA type or the operand of typeof is a variably modified
2143    type.  */
2144
2145 static void
2146 record_maybe_used_decl (tree decl)
2147 {
2148   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2149   t->decl = decl;
2150   t->level = in_sizeof + in_typeof;
2151   t->next = maybe_used_decls;
2152   maybe_used_decls = t;
2153 }
2154
2155 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2156    USED is false, just discard them.  If it is true, mark them used
2157    (if no longer inside sizeof or typeof) or move them to the next
2158    level up (if still inside sizeof or typeof).  */
2159
2160 void
2161 pop_maybe_used (bool used)
2162 {
2163   struct maybe_used_decl *p = maybe_used_decls;
2164   int cur_level = in_sizeof + in_typeof;
2165   while (p && p->level > cur_level)
2166     {
2167       if (used)
2168         {
2169           if (cur_level == 0)
2170             C_DECL_USED (p->decl) = 1;
2171           else
2172             p->level = cur_level;
2173         }
2174       p = p->next;
2175     }
2176   if (!used || cur_level == 0)
2177     maybe_used_decls = p;
2178 }
2179
2180 /* Return the result of sizeof applied to EXPR.  */
2181
2182 struct c_expr
2183 c_expr_sizeof_expr (struct c_expr expr)
2184 {
2185   struct c_expr ret;
2186   if (expr.value == error_mark_node)
2187     {
2188       ret.value = error_mark_node;
2189       ret.original_code = ERROR_MARK;
2190       pop_maybe_used (false);
2191     }
2192   else
2193     {
2194       ret.value = c_sizeof (TREE_TYPE (expr.value));
2195       ret.original_code = ERROR_MARK;
2196       if (c_vla_type_p (TREE_TYPE (expr.value)))
2197         {
2198           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2199           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2200         }
2201       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2202     }
2203   return ret;
2204 }
2205
2206 /* Return the result of sizeof applied to T, a structure for the type
2207    name passed to sizeof (rather than the type itself).  */
2208
2209 struct c_expr
2210 c_expr_sizeof_type (struct c_type_name *t)
2211 {
2212   tree type;
2213   struct c_expr ret;
2214   type = groktypename (t);
2215   ret.value = c_sizeof (type);
2216   ret.original_code = ERROR_MARK;
2217   pop_maybe_used (type != error_mark_node
2218                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2219   return ret;
2220 }
2221
2222 /* Build a function call to function FUNCTION with parameters PARAMS.
2223    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2224    TREE_VALUE of each node is a parameter-expression.
2225    FUNCTION's data type may be a function type or a pointer-to-function.  */
2226
2227 tree
2228 build_function_call (tree function, tree params)
2229 {
2230   tree fntype, fundecl = 0;
2231   tree name = NULL_TREE, result;
2232   tree tem;
2233   int nargs;
2234   tree *argarray;
2235
2236
2237   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2238   STRIP_TYPE_NOPS (function);
2239
2240   /* Convert anything with function type to a pointer-to-function.  */
2241   if (TREE_CODE (function) == FUNCTION_DECL)
2242     {
2243       /* Implement type-directed function overloading for builtins.
2244          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2245          handle all the type checking.  The result is a complete expression
2246          that implements this function call.  */
2247       tem = resolve_overloaded_builtin (function, params);
2248       if (tem)
2249         return tem;
2250
2251       name = DECL_NAME (function);
2252       fundecl = function;
2253     }
2254   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2255     function = function_to_pointer_conversion (function);
2256
2257   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2258      expressions, like those used for ObjC messenger dispatches.  */
2259   function = objc_rewrite_function_call (function, params);
2260
2261   fntype = TREE_TYPE (function);
2262
2263   if (TREE_CODE (fntype) == ERROR_MARK)
2264     return error_mark_node;
2265
2266   if (!(TREE_CODE (fntype) == POINTER_TYPE
2267         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2268     {
2269       error ("called object %qE is not a function", function);
2270       return error_mark_node;
2271     }
2272
2273   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2274     current_function_returns_abnormally = 1;
2275
2276   /* fntype now gets the type of function pointed to.  */
2277   fntype = TREE_TYPE (fntype);
2278
2279   /* Check that the function is called through a compatible prototype.
2280      If it is not, replace the call by a trap, wrapped up in a compound
2281      expression if necessary.  This has the nice side-effect to prevent
2282      the tree-inliner from generating invalid assignment trees which may
2283      blow up in the RTL expander later.  */
2284   if ((TREE_CODE (function) == NOP_EXPR
2285        || TREE_CODE (function) == CONVERT_EXPR)
2286       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2287       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2288       && !comptypes (fntype, TREE_TYPE (tem)))
2289     {
2290       tree return_type = TREE_TYPE (fntype);
2291       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2292                                        NULL_TREE);
2293
2294       /* This situation leads to run-time undefined behavior.  We can't,
2295          therefore, simply error unless we can prove that all possible
2296          executions of the program must execute the code.  */
2297       warning (0, "function called through a non-compatible type");
2298
2299       /* We can, however, treat "undefined" any way we please.
2300          Call abort to encourage the user to fix the program.  */
2301       inform ("if this code is reached, the program will abort");
2302
2303       if (VOID_TYPE_P (return_type))
2304         return trap;
2305       else
2306         {
2307           tree rhs;
2308
2309           if (AGGREGATE_TYPE_P (return_type))
2310             rhs = build_compound_literal (return_type,
2311                                           build_constructor (return_type, 0));
2312           else
2313             rhs = fold_convert (return_type, integer_zero_node);
2314
2315           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2316         }
2317     }
2318
2319   /* Convert the parameters to the types declared in the
2320      function prototype, or apply default promotions.  */
2321
2322   nargs = list_length (params);
2323   argarray = (tree *) alloca (nargs * sizeof (tree));
2324   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2325                              params, function, fundecl);
2326   if (nargs < 0)
2327     return error_mark_node;
2328
2329   /* Check that the arguments to the function are valid.  */
2330
2331   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2332                             TYPE_ARG_TYPES (fntype));
2333
2334   if (require_constant_value)
2335     {
2336       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2337                                                   function, nargs, argarray);
2338       if (TREE_CONSTANT (result)
2339           && (name == NULL_TREE
2340               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2341         pedwarn_init ("initializer element is not constant");
2342     }
2343   else
2344     result = fold_build_call_array (TREE_TYPE (fntype),
2345                                     function, nargs, argarray);
2346
2347   if (VOID_TYPE_P (TREE_TYPE (result)))
2348     return result;
2349   return require_complete_type (result);
2350 }
2351 \f
2352 /* Convert the argument expressions in the list VALUES
2353    to the types in the list TYPELIST.  The resulting arguments are
2354    stored in the array ARGARRAY which has size NARGS.
2355
2356    If TYPELIST is exhausted, or when an element has NULL as its type,
2357    perform the default conversions.
2358
2359    PARMLIST is the chain of parm decls for the function being called.
2360    It may be 0, if that info is not available.
2361    It is used only for generating error messages.
2362
2363    FUNCTION is a tree for the called function.  It is used only for
2364    error messages, where it is formatted with %qE.
2365
2366    This is also where warnings about wrong number of args are generated.
2367
2368    VALUES is a chain of TREE_LIST nodes with the elements of the list
2369    in the TREE_VALUE slots of those nodes.
2370
2371    Returns the actual number of arguments processed (which may be less
2372    than NARGS in some error situations), or -1 on failure.  */
2373
2374 static int
2375 convert_arguments (int nargs, tree *argarray,
2376                    tree typelist, tree values, tree function, tree fundecl)
2377 {
2378   tree typetail, valtail;
2379   int parmnum;
2380   tree selector;
2381
2382   /* Change pointer to function to the function itself for
2383      diagnostics.  */
2384   if (TREE_CODE (function) == ADDR_EXPR
2385       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2386     function = TREE_OPERAND (function, 0);
2387
2388   /* Handle an ObjC selector specially for diagnostics.  */
2389   selector = objc_message_selector ();
2390
2391   /* Scan the given expressions and types, producing individual
2392      converted arguments and storing them in ARGARRAY.  */
2393
2394   for (valtail = values, typetail = typelist, parmnum = 0;
2395        valtail;
2396        valtail = TREE_CHAIN (valtail), parmnum++)
2397     {
2398       tree type = typetail ? TREE_VALUE (typetail) : 0;
2399       tree val = TREE_VALUE (valtail);
2400       tree rname = function;
2401       int argnum = parmnum + 1;
2402       const char *invalid_func_diag;
2403
2404       if (type == void_type_node)
2405         {
2406           error ("too many arguments to function %qE", function);
2407           return parmnum;
2408         }
2409
2410       if (selector && argnum > 2)
2411         {
2412           rname = selector;
2413           argnum -= 2;
2414         }
2415
2416       STRIP_TYPE_NOPS (val);
2417
2418       val = require_complete_type (val);
2419
2420       if (type != 0)
2421         {
2422           /* Formal parm type is specified by a function prototype.  */
2423           tree parmval;
2424
2425           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2426             {
2427               error ("type of formal parameter %d is incomplete", parmnum + 1);
2428               parmval = val;
2429             }
2430           else
2431             {
2432               /* Optionally warn about conversions that
2433                  differ from the default conversions.  */
2434               if (warn_traditional_conversion || warn_traditional)
2435                 {
2436                   unsigned int formal_prec = TYPE_PRECISION (type);
2437
2438                   if (INTEGRAL_TYPE_P (type)
2439                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2440                     warning (0, "passing argument %d of %qE as integer "
2441                              "rather than floating due to prototype",
2442                              argnum, rname);
2443                   if (INTEGRAL_TYPE_P (type)
2444                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2445                     warning (0, "passing argument %d of %qE as integer "
2446                              "rather than complex due to prototype",
2447                              argnum, rname);
2448                   else if (TREE_CODE (type) == COMPLEX_TYPE
2449                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2450                     warning (0, "passing argument %d of %qE as complex "
2451                              "rather than floating due to prototype",
2452                              argnum, rname);
2453                   else if (TREE_CODE (type) == REAL_TYPE
2454                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2455                     warning (0, "passing argument %d of %qE as floating "
2456                              "rather than integer due to prototype",
2457                              argnum, rname);
2458                   else if (TREE_CODE (type) == COMPLEX_TYPE
2459                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2460                     warning (0, "passing argument %d of %qE as complex "
2461                              "rather than integer due to prototype",
2462                              argnum, rname);
2463                   else if (TREE_CODE (type) == REAL_TYPE
2464                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2465                     warning (0, "passing argument %d of %qE as floating "
2466                              "rather than complex due to prototype",
2467                              argnum, rname);
2468                   /* ??? At some point, messages should be written about
2469                      conversions between complex types, but that's too messy
2470                      to do now.  */
2471                   else if (TREE_CODE (type) == REAL_TYPE
2472                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2473                     {
2474                       /* Warn if any argument is passed as `float',
2475                          since without a prototype it would be `double'.  */
2476                       if (formal_prec == TYPE_PRECISION (float_type_node)
2477                           && type != dfloat32_type_node)
2478                         warning (0, "passing argument %d of %qE as %<float%> "
2479                                  "rather than %<double%> due to prototype",
2480                                  argnum, rname);
2481
2482                       /* Warn if mismatch between argument and prototype
2483                          for decimal float types.  Warn of conversions with
2484                          binary float types and of precision narrowing due to
2485                          prototype. */
2486                       else if (type != TREE_TYPE (val)
2487                                && (type == dfloat32_type_node
2488                                    || type == dfloat64_type_node
2489                                    || type == dfloat128_type_node
2490                                    || TREE_TYPE (val) == dfloat32_type_node
2491                                    || TREE_TYPE (val) == dfloat64_type_node
2492                                    || TREE_TYPE (val) == dfloat128_type_node)
2493                                && (formal_prec
2494                                    <= TYPE_PRECISION (TREE_TYPE (val))
2495                                    || (type == dfloat128_type_node
2496                                        && (TREE_TYPE (val)
2497                                            != dfloat64_type_node
2498                                            && (TREE_TYPE (val)
2499                                                != dfloat32_type_node)))
2500                                    || (type == dfloat64_type_node
2501                                        && (TREE_TYPE (val)
2502                                            != dfloat32_type_node))))
2503                         warning (0, "passing argument %d of %qE as %qT "
2504                                  "rather than %qT due to prototype",
2505                                  argnum, rname, type, TREE_TYPE (val));
2506
2507                     }
2508                   /* Detect integer changing in width or signedness.
2509                      These warnings are only activated with
2510                      -Wtraditional-conversion, not with -Wtraditional.  */
2511                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2512                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2513                     {
2514                       tree would_have_been = default_conversion (val);
2515                       tree type1 = TREE_TYPE (would_have_been);
2516
2517                       if (TREE_CODE (type) == ENUMERAL_TYPE
2518                           && (TYPE_MAIN_VARIANT (type)
2519                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2520                         /* No warning if function asks for enum
2521                            and the actual arg is that enum type.  */
2522                         ;
2523                       else if (formal_prec != TYPE_PRECISION (type1))
2524                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2525                                  "with different width due to prototype",
2526                                  argnum, rname);
2527                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2528                         ;
2529                       /* Don't complain if the formal parameter type
2530                          is an enum, because we can't tell now whether
2531                          the value was an enum--even the same enum.  */
2532                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2533                         ;
2534                       else if (TREE_CODE (val) == INTEGER_CST
2535                                && int_fits_type_p (val, type))
2536                         /* Change in signedness doesn't matter
2537                            if a constant value is unaffected.  */
2538                         ;
2539                       /* If the value is extended from a narrower
2540                          unsigned type, it doesn't matter whether we
2541                          pass it as signed or unsigned; the value
2542                          certainly is the same either way.  */
2543                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2544                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2545                         ;
2546                       else if (TYPE_UNSIGNED (type))
2547                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2548                                  "as unsigned due to prototype",
2549                                  argnum, rname);
2550                       else
2551                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2552                                  "as signed due to prototype", argnum, rname);
2553                     }
2554                 }
2555
2556               parmval = convert_for_assignment (type, val, ic_argpass,
2557                                                 fundecl, function,
2558                                                 parmnum + 1);
2559
2560               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2561                   && INTEGRAL_TYPE_P (type)
2562                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2563                 parmval = default_conversion (parmval);
2564             }
2565           argarray[parmnum] = parmval;
2566         }
2567       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2568                && (TYPE_PRECISION (TREE_TYPE (val))
2569                    < TYPE_PRECISION (double_type_node))
2570                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2571         /* Convert `float' to `double'.  */
2572         argarray[parmnum] = convert (double_type_node, val);
2573       else if ((invalid_func_diag =
2574                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2575         {
2576           error (invalid_func_diag);
2577           return -1;
2578         }
2579       else
2580         /* Convert `short' and `char' to full-size `int'.  */
2581         argarray[parmnum] = default_conversion (val);
2582
2583       if (typetail)
2584         typetail = TREE_CHAIN (typetail);
2585     }
2586
2587   gcc_assert (parmnum == nargs);
2588
2589   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2590     {
2591       error ("too few arguments to function %qE", function);
2592       return -1;
2593     }
2594
2595   return parmnum;
2596 }
2597 \f
2598 /* This is the entry point used by the parser to build unary operators
2599    in the input.  CODE, a tree_code, specifies the unary operator, and
2600    ARG is the operand.  For unary plus, the C parser currently uses
2601    CONVERT_EXPR for code.  */
2602
2603 struct c_expr
2604 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2605 {
2606   struct c_expr result;
2607
2608   result.original_code = ERROR_MARK;
2609   result.value = build_unary_op (code, arg.value, 0);
2610
2611   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2612     overflow_warning (result.value);
2613
2614   return result;
2615 }
2616
2617 /* This is the entry point used by the parser to build binary operators
2618    in the input.  CODE, a tree_code, specifies the binary operator, and
2619    ARG1 and ARG2 are the operands.  In addition to constructing the
2620    expression, we check for operands that were written with other binary
2621    operators in a way that is likely to confuse the user.  */
2622
2623 struct c_expr
2624 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2625                         struct c_expr arg2)
2626 {
2627   struct c_expr result;
2628
2629   enum tree_code code1 = arg1.original_code;
2630   enum tree_code code2 = arg2.original_code;
2631
2632   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2633   result.original_code = code;
2634
2635   if (TREE_CODE (result.value) == ERROR_MARK)
2636     return result;
2637
2638   /* Check for cases such as x+y<<z which users are likely
2639      to misinterpret.  */
2640   if (warn_parentheses)
2641     warn_about_parentheses (code, code1, code2);
2642
2643   if (code1 != tcc_comparison)
2644     warn_logical_operator (code, arg1.value, arg2.value);
2645
2646   /* Warn about comparisons against string literals, with the exception
2647      of testing for equality or inequality of a string literal with NULL.  */
2648   if (code == EQ_EXPR || code == NE_EXPR)
2649     {
2650       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2651           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2652         warning (OPT_Waddress, "comparison with string literal results in unspecified behaviour");
2653     }
2654   else if (TREE_CODE_CLASS (code) == tcc_comparison
2655            && (code1 == STRING_CST || code2 == STRING_CST))
2656     warning (OPT_Waddress, "comparison with string literal results in unspecified behaviour");
2657
2658   if (TREE_OVERFLOW_P (result.value)
2659       && !TREE_OVERFLOW_P (arg1.value)
2660       && !TREE_OVERFLOW_P (arg2.value))
2661     overflow_warning (result.value);
2662
2663   return result;
2664 }
2665 \f
2666 /* Return a tree for the difference of pointers OP0 and OP1.
2667    The resulting tree has type int.  */
2668
2669 static tree
2670 pointer_diff (tree op0, tree op1)
2671 {
2672   tree restype = ptrdiff_type_node;
2673
2674   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2675   tree con0, con1, lit0, lit1;
2676   tree orig_op1 = op1;
2677
2678   if (pedantic || warn_pointer_arith)
2679     {
2680       if (TREE_CODE (target_type) == VOID_TYPE)
2681         pedwarn ("pointer of type %<void *%> used in subtraction");
2682       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2683         pedwarn ("pointer to a function used in subtraction");
2684     }
2685
2686   /* If the conversion to ptrdiff_type does anything like widening or
2687      converting a partial to an integral mode, we get a convert_expression
2688      that is in the way to do any simplifications.
2689      (fold-const.c doesn't know that the extra bits won't be needed.
2690      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2691      different mode in place.)
2692      So first try to find a common term here 'by hand'; we want to cover
2693      at least the cases that occur in legal static initializers.  */
2694   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2695       && (TYPE_PRECISION (TREE_TYPE (op0))
2696           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2697     con0 = TREE_OPERAND (op0, 0);
2698   else
2699     con0 = op0;
2700   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2701       && (TYPE_PRECISION (TREE_TYPE (op1))
2702           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2703     con1 = TREE_OPERAND (op1, 0);
2704   else
2705     con1 = op1;
2706
2707   if (TREE_CODE (con0) == PLUS_EXPR)
2708     {
2709       lit0 = TREE_OPERAND (con0, 1);
2710       con0 = TREE_OPERAND (con0, 0);
2711     }
2712   else
2713     lit0 = integer_zero_node;
2714
2715   if (TREE_CODE (con1) == PLUS_EXPR)
2716     {
2717       lit1 = TREE_OPERAND (con1, 1);
2718       con1 = TREE_OPERAND (con1, 0);
2719     }
2720   else
2721     lit1 = integer_zero_node;
2722
2723   if (operand_equal_p (con0, con1, 0))
2724     {
2725       op0 = lit0;
2726       op1 = lit1;
2727     }
2728
2729
2730   /* First do the subtraction as integers;
2731      then drop through to build the divide operator.
2732      Do not do default conversions on the minus operator
2733      in case restype is a short type.  */
2734
2735   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2736                          convert (restype, op1), 0);
2737   /* This generates an error if op1 is pointer to incomplete type.  */
2738   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2739     error ("arithmetic on pointer to an incomplete type");
2740
2741   /* This generates an error if op0 is pointer to incomplete type.  */
2742   op1 = c_size_in_bytes (target_type);
2743
2744   /* Divide by the size, in easiest possible way.  */
2745   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2746 }
2747 \f
2748 /* Construct and perhaps optimize a tree representation
2749    for a unary operation.  CODE, a tree_code, specifies the operation
2750    and XARG is the operand.
2751    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2752    the default promotions (such as from short to int).
2753    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2754    allows non-lvalues; this is only used to handle conversion of non-lvalue
2755    arrays to pointers in C99.  */
2756
2757 tree
2758 build_unary_op (enum tree_code code, tree xarg, int flag)
2759 {
2760   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2761   tree arg = xarg;
2762   tree argtype = 0;
2763   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2764   tree val;
2765   int noconvert = flag;
2766   const char *invalid_op_diag;
2767
2768   if (typecode == ERROR_MARK)
2769     return error_mark_node;
2770   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2771     typecode = INTEGER_TYPE;
2772
2773   if ((invalid_op_diag
2774        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2775     {
2776       error (invalid_op_diag);
2777       return error_mark_node;
2778     }
2779
2780   switch (code)
2781     {
2782     case CONVERT_EXPR:
2783       /* This is used for unary plus, because a CONVERT_EXPR
2784          is enough to prevent anybody from looking inside for
2785          associativity, but won't generate any code.  */
2786       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2787             || typecode == COMPLEX_TYPE
2788             || typecode == VECTOR_TYPE))
2789         {
2790           error ("wrong type argument to unary plus");
2791           return error_mark_node;
2792         }
2793       else if (!noconvert)
2794         arg = default_conversion (arg);
2795       arg = non_lvalue (arg);
2796       break;
2797
2798     case NEGATE_EXPR:
2799       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2800             || typecode == COMPLEX_TYPE
2801             || typecode == VECTOR_TYPE))
2802         {
2803           error ("wrong type argument to unary minus");
2804           return error_mark_node;
2805         }
2806       else if (!noconvert)
2807         arg = default_conversion (arg);
2808       break;
2809
2810     case BIT_NOT_EXPR:
2811       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2812         {
2813           if (!noconvert)
2814             arg = default_conversion (arg);
2815         }
2816       else if (typecode == COMPLEX_TYPE)
2817         {
2818           code = CONJ_EXPR;
2819           if (pedantic)
2820             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2821           if (!noconvert)
2822             arg = default_conversion (arg);
2823         }
2824       else
2825         {
2826           error ("wrong type argument to bit-complement");
2827           return error_mark_node;
2828         }
2829       break;
2830
2831     case ABS_EXPR:
2832       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2833         {
2834           error ("wrong type argument to abs");
2835           return error_mark_node;
2836         }
2837       else if (!noconvert)
2838         arg = default_conversion (arg);
2839       break;
2840
2841     case CONJ_EXPR:
2842       /* Conjugating a real value is a no-op, but allow it anyway.  */
2843       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2844             || typecode == COMPLEX_TYPE))
2845         {
2846           error ("wrong type argument to conjugation");
2847           return error_mark_node;
2848         }
2849       else if (!noconvert)
2850         arg = default_conversion (arg);
2851       break;
2852
2853     case TRUTH_NOT_EXPR:
2854       if (typecode != INTEGER_TYPE
2855           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2856           && typecode != COMPLEX_TYPE)
2857         {
2858           error ("wrong type argument to unary exclamation mark");
2859           return error_mark_node;
2860         }
2861       arg = c_objc_common_truthvalue_conversion (arg);
2862       return invert_truthvalue (arg);
2863
2864     case REALPART_EXPR:
2865       if (TREE_CODE (arg) == COMPLEX_CST)
2866         return TREE_REALPART (arg);
2867       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2868         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2869       else
2870         return arg;
2871
2872     case IMAGPART_EXPR:
2873       if (TREE_CODE (arg) == COMPLEX_CST)
2874         return TREE_IMAGPART (arg);
2875       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2876         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2877       else
2878         return convert (TREE_TYPE (arg), integer_zero_node);
2879
2880     case PREINCREMENT_EXPR:
2881     case POSTINCREMENT_EXPR:
2882     case PREDECREMENT_EXPR:
2883     case POSTDECREMENT_EXPR:
2884
2885       /* Increment or decrement the real part of the value,
2886          and don't change the imaginary part.  */
2887       if (typecode == COMPLEX_TYPE)
2888         {
2889           tree real, imag;
2890
2891           if (pedantic)
2892             pedwarn ("ISO C does not support %<++%> and %<--%>"
2893                      " on complex types");
2894
2895           arg = stabilize_reference (arg);
2896           real = build_unary_op (REALPART_EXPR, arg, 1);
2897           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2898           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2899                          build_unary_op (code, real, 1), imag);
2900         }
2901
2902       /* Report invalid types.  */
2903
2904       if (typecode != POINTER_TYPE
2905           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2906         {
2907           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2908             error ("wrong type argument to increment");
2909           else
2910             error ("wrong type argument to decrement");
2911
2912           return error_mark_node;
2913         }
2914
2915       {
2916         tree inc;
2917         tree result_type = TREE_TYPE (arg);
2918
2919         arg = get_unwidened (arg, 0);
2920         argtype = TREE_TYPE (arg);
2921
2922         /* Compute the increment.  */
2923
2924         if (typecode == POINTER_TYPE)
2925           {
2926             /* If pointer target is an undefined struct,
2927                we just cannot know how to do the arithmetic.  */
2928             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2929               {
2930                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2931                   error ("increment of pointer to unknown structure");
2932                 else
2933                   error ("decrement of pointer to unknown structure");
2934               }
2935             else if ((pedantic || warn_pointer_arith)
2936                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2937                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2938               {
2939                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2940                   pedwarn ("wrong type argument to increment");
2941                 else
2942                   pedwarn ("wrong type argument to decrement");
2943               }
2944
2945             inc = c_size_in_bytes (TREE_TYPE (result_type));
2946           }
2947         else
2948           inc = integer_one_node;
2949
2950         inc = convert (argtype, inc);
2951
2952         /* Complain about anything else that is not a true lvalue.  */
2953         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2954                                     || code == POSTINCREMENT_EXPR)
2955                                    ? lv_increment
2956                                    : lv_decrement)))
2957           return error_mark_node;
2958
2959         /* Report a read-only lvalue.  */
2960         if (TREE_READONLY (arg))
2961           {
2962             readonly_error (arg,
2963                             ((code == PREINCREMENT_EXPR
2964                               || code == POSTINCREMENT_EXPR)
2965                              ? lv_increment : lv_decrement));
2966             return error_mark_node;
2967           }
2968
2969         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2970           val = boolean_increment (code, arg);
2971         else
2972           val = build2 (code, TREE_TYPE (arg), arg, inc);
2973         TREE_SIDE_EFFECTS (val) = 1;
2974         val = convert (result_type, val);
2975         if (TREE_CODE (val) != code)
2976           TREE_NO_WARNING (val) = 1;
2977         return val;
2978       }
2979
2980     case ADDR_EXPR:
2981       /* Note that this operation never does default_conversion.  */
2982
2983       /* Let &* cancel out to simplify resulting code.  */
2984       if (TREE_CODE (arg) == INDIRECT_REF)
2985         {
2986           /* Don't let this be an lvalue.  */
2987           if (lvalue_p (TREE_OPERAND (arg, 0)))
2988             return non_lvalue (TREE_OPERAND (arg, 0));
2989           return TREE_OPERAND (arg, 0);
2990         }
2991
2992       /* For &x[y], return x+y */
2993       if (TREE_CODE (arg) == ARRAY_REF)
2994         {
2995           tree op0 = TREE_OPERAND (arg, 0);
2996           if (!c_mark_addressable (op0))
2997             return error_mark_node;
2998           return build_binary_op (PLUS_EXPR,
2999                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3000                                    ? array_to_pointer_conversion (op0)
3001                                    : op0),
3002                                   TREE_OPERAND (arg, 1), 1);
3003         }
3004
3005       /* Anything not already handled and not a true memory reference
3006          or a non-lvalue array is an error.  */
3007       else if (typecode != FUNCTION_TYPE && !flag
3008                && !lvalue_or_else (arg, lv_addressof))
3009         return error_mark_node;
3010
3011       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3012       argtype = TREE_TYPE (arg);
3013
3014       /* If the lvalue is const or volatile, merge that into the type
3015          to which the address will point.  Note that you can't get a
3016          restricted pointer by taking the address of something, so we
3017          only have to deal with `const' and `volatile' here.  */
3018       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3019           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3020           argtype = c_build_type_variant (argtype,
3021                                           TREE_READONLY (arg),
3022                                           TREE_THIS_VOLATILE (arg));
3023
3024       if (!c_mark_addressable (arg))
3025         return error_mark_node;
3026
3027       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3028                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3029
3030       argtype = build_pointer_type (argtype);
3031
3032       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3033          when we have proper support for integer constant expressions.  */
3034       val = get_base_address (arg);
3035       if (val && TREE_CODE (val) == INDIRECT_REF
3036           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3037         {
3038           tree op0 = fold_convert (argtype, fold_offsetof (arg, val)), op1;
3039
3040           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3041           return fold_build2 (PLUS_EXPR, argtype, op0, op1);
3042         }
3043
3044       val = build1 (ADDR_EXPR, argtype, arg);
3045
3046       return val;
3047
3048     default:
3049       gcc_unreachable ();
3050     }
3051
3052   if (argtype == 0)
3053     argtype = TREE_TYPE (arg);
3054   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3055                                 : fold_build1 (code, argtype, arg);
3056 }
3057
3058 /* Return nonzero if REF is an lvalue valid for this language.
3059    Lvalues can be assigned, unless their type has TYPE_READONLY.
3060    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3061
3062 static int
3063 lvalue_p (tree ref)
3064 {
3065   enum tree_code code = TREE_CODE (ref);
3066
3067   switch (code)
3068     {
3069     case REALPART_EXPR:
3070     case IMAGPART_EXPR:
3071     case COMPONENT_REF:
3072       return lvalue_p (TREE_OPERAND (ref, 0));
3073
3074     case COMPOUND_LITERAL_EXPR:
3075     case STRING_CST:
3076       return 1;
3077
3078     case INDIRECT_REF:
3079     case ARRAY_REF:
3080     case VAR_DECL:
3081     case PARM_DECL:
3082     case RESULT_DECL:
3083     case ERROR_MARK:
3084       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3085               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3086
3087     case BIND_EXPR:
3088       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3089
3090     default:
3091       return 0;
3092     }
3093 }
3094 \f
3095 /* Give an error for storing in something that is 'const'.  */
3096
3097 static void
3098 readonly_error (tree arg, enum lvalue_use use)
3099 {
3100   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3101               || use == lv_asm);
3102   /* Using this macro rather than (for example) arrays of messages
3103      ensures that all the format strings are checked at compile
3104      time.  */
3105 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3106                                    : (use == lv_increment ? (I)         \
3107                                    : (use == lv_decrement ? (D) : (AS))))
3108   if (TREE_CODE (arg) == COMPONENT_REF)
3109     {
3110       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3111         readonly_error (TREE_OPERAND (arg, 0), use);
3112       else
3113         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3114                              G_("increment of read-only member %qD"),
3115                              G_("decrement of read-only member %qD"),
3116                              G_("read-only member %qD used as %<asm%> output")),
3117                TREE_OPERAND (arg, 1));
3118     }
3119   else if (TREE_CODE (arg) == VAR_DECL)
3120     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3121                          G_("increment of read-only variable %qD"),
3122                          G_("decrement of read-only variable %qD"),
3123                          G_("read-only variable %qD used as %<asm%> output")),
3124            arg);
3125   else
3126     error (READONLY_MSG (G_("assignment of read-only location"),
3127                          G_("increment of read-only location"),
3128                          G_("decrement of read-only location"),
3129                          G_("read-only location used as %<asm%> output")));
3130 }
3131
3132
3133 /* Return nonzero if REF is an lvalue valid for this language;
3134    otherwise, print an error message and return zero.  USE says
3135    how the lvalue is being used and so selects the error message.  */
3136
3137 static int
3138 lvalue_or_else (tree ref, enum lvalue_use use)
3139 {
3140   int win = lvalue_p (ref);
3141
3142   if (!win)
3143     lvalue_error (use);
3144
3145   return win;
3146 }
3147 \f
3148 /* Mark EXP saying that we need to be able to take the
3149    address of it; it should not be allocated in a register.
3150    Returns true if successful.  */
3151
3152 bool
3153 c_mark_addressable (tree exp)
3154 {
3155   tree x = exp;
3156
3157   while (1)
3158     switch (TREE_CODE (x))
3159       {
3160       case COMPONENT_REF:
3161         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3162           {
3163             error
3164               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3165             return false;
3166           }
3167
3168         /* ... fall through ...  */
3169
3170       case ADDR_EXPR:
3171       case ARRAY_REF:
3172       case REALPART_EXPR:
3173       case IMAGPART_EXPR:
3174         x = TREE_OPERAND (x, 0);
3175         break;
3176
3177       case COMPOUND_LITERAL_EXPR:
3178       case CONSTRUCTOR:
3179         TREE_ADDRESSABLE (x) = 1;
3180         return true;
3181
3182       case VAR_DECL:
3183       case CONST_DECL:
3184       case PARM_DECL:
3185       case RESULT_DECL:
3186         if (C_DECL_REGISTER (x)
3187             && DECL_NONLOCAL (x))
3188           {
3189             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3190               {
3191                 error
3192                   ("global register variable %qD used in nested function", x);
3193                 return false;
3194               }
3195             pedwarn ("register variable %qD used in nested function", x);
3196           }
3197         else if (C_DECL_REGISTER (x))
3198           {
3199             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3200               error ("address of global register variable %qD requested", x);
3201             else
3202               error ("address of register variable %qD requested", x);
3203             return false;
3204           }
3205
3206         /* drops in */
3207       case FUNCTION_DECL:
3208         TREE_ADDRESSABLE (x) = 1;
3209         /* drops out */
3210       default:
3211         return true;
3212     }
3213 }
3214 \f
3215 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3216
3217 tree
3218 build_conditional_expr (tree ifexp, tree op1, tree op2)
3219 {
3220   tree type1;
3221   tree type2;
3222   enum tree_code code1;
3223   enum tree_code code2;
3224   tree result_type = NULL;
3225   tree orig_op1 = op1, orig_op2 = op2;
3226
3227   /* Promote both alternatives.  */
3228
3229   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3230     op1 = default_conversion (op1);
3231   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3232     op2 = default_conversion (op2);
3233
3234   if (TREE_CODE (ifexp) == ERROR_MARK
3235       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3236       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3237     return error_mark_node;
3238
3239   type1 = TREE_TYPE (op1);
3240   code1 = TREE_CODE (type1);
3241   type2 = TREE_TYPE (op2);
3242   code2 = TREE_CODE (type2);
3243
3244   /* C90 does not permit non-lvalue arrays in conditional expressions.
3245      In C99 they will be pointers by now.  */
3246   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3247     {
3248       error ("non-lvalue array in conditional expression");
3249       return error_mark_node;
3250     }
3251
3252   /* Quickly detect the usual case where op1 and op2 have the same type
3253      after promotion.  */
3254   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3255     {
3256       if (type1 == type2)
3257         result_type = type1;
3258       else
3259         result_type = TYPE_MAIN_VARIANT (type1);
3260     }
3261   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3262             || code1 == COMPLEX_TYPE)
3263            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3264                || code2 == COMPLEX_TYPE))
3265     {
3266       result_type = c_common_type (type1, type2);
3267
3268       /* If -Wsign-compare, warn here if type1 and type2 have
3269          different signedness.  We'll promote the signed to unsigned
3270          and later code won't know it used to be different.
3271          Do this check on the original types, so that explicit casts
3272          will be considered, but default promotions won't.  */
3273       if (warn_sign_compare && !skip_evaluation)
3274         {
3275           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3276           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3277
3278           if (unsigned_op1 ^ unsigned_op2)
3279             {
3280               bool ovf;
3281
3282               /* Do not warn if the result type is signed, since the
3283                  signed type will only be chosen if it can represent
3284                  all the values of the unsigned type.  */
3285               if (!TYPE_UNSIGNED (result_type))
3286                 /* OK */;
3287               /* Do not warn if the signed quantity is an unsuffixed
3288                  integer literal (or some static constant expression
3289                  involving such literals) and it is non-negative.  */
3290               else if ((unsigned_op2
3291                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3292                        || (unsigned_op1
3293                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3294                 /* OK */;
3295               else
3296                 warning (0, "signed and unsigned type in conditional expression");
3297             }
3298         }
3299     }
3300   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3301     {
3302       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3303         pedwarn ("ISO C forbids conditional expr with only one void side");
3304       result_type = void_type_node;
3305     }
3306   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3307     {
3308       if (comp_target_types (type1, type2))
3309         result_type = common_pointer_type (type1, type2);
3310       else if (null_pointer_constant_p (orig_op1))
3311         result_type = qualify_type (type2, type1);
3312       else if (null_pointer_constant_p (orig_op2))
3313         result_type = qualify_type (type1, type2);
3314       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3315         {
3316           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3317             pedwarn ("ISO C forbids conditional expr between "
3318                      "%<void *%> and function pointer");
3319           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3320                                                           TREE_TYPE (type2)));
3321         }
3322       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3323         {
3324           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3325             pedwarn ("ISO C forbids conditional expr between "
3326                      "%<void *%> and function pointer");
3327           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3328                                                           TREE_TYPE (type1)));
3329         }
3330       else
3331         {
3332           pedwarn ("pointer type mismatch in conditional expression");
3333           result_type = build_pointer_type (void_type_node);
3334         }
3335     }
3336   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3337     {
3338       if (!null_pointer_constant_p (orig_op2))
3339         pedwarn ("pointer/integer type mismatch in conditional expression");
3340       else
3341         {
3342           op2 = null_pointer_node;
3343         }
3344       result_type = type1;
3345     }
3346   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3347     {
3348       if (!null_pointer_constant_p (orig_op1))
3349         pedwarn ("pointer/integer type mismatch in conditional expression");
3350       else
3351         {
3352           op1 = null_pointer_node;
3353         }
3354       result_type = type2;
3355     }
3356
3357   if (!result_type)
3358     {
3359       if (flag_cond_mismatch)
3360         result_type = void_type_node;
3361       else
3362         {
3363           error ("type mismatch in conditional expression");
3364           return error_mark_node;
3365         }
3366     }
3367
3368   /* Merge const and volatile flags of the incoming types.  */
3369   result_type
3370     = build_type_variant (result_type,
3371                           TREE_READONLY (op1) || TREE_READONLY (op2),
3372                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3373
3374   if (result_type != TREE_TYPE (op1))
3375     op1 = convert_and_check (result_type, op1);
3376   if (result_type != TREE_TYPE (op2))
3377     op2 = convert_and_check (result_type, op2);
3378
3379   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3380 }
3381 \f
3382 /* Return a compound expression that performs two expressions and
3383    returns the value of the second of them.  */
3384
3385 tree
3386 build_compound_expr (tree expr1, tree expr2)
3387 {
3388   if (!TREE_SIDE_EFFECTS (expr1))
3389     {
3390       /* The left-hand operand of a comma expression is like an expression
3391          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3392          any side-effects, unless it was explicitly cast to (void).  */
3393       if (warn_unused_value)
3394         {
3395           if (VOID_TYPE_P (TREE_TYPE (expr1))
3396               && (TREE_CODE (expr1) == NOP_EXPR
3397                   || TREE_CODE (expr1) == CONVERT_EXPR))
3398             ; /* (void) a, b */
3399           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3400                    && TREE_CODE (expr1) == COMPOUND_EXPR
3401                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3402                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
3403             ; /* (void) a, (void) b, c */
3404           else
3405             warning (0, "left-hand operand of comma expression has no effect");
3406         }
3407     }
3408
3409   /* With -Wunused, we should also warn if the left-hand operand does have
3410      side-effects, but computes a value which is not used.  For example, in
3411      `foo() + bar(), baz()' the result of the `+' operator is not used,
3412      so we should issue a warning.  */
3413   else if (warn_unused_value)
3414     warn_if_unused_value (expr1, input_location);
3415
3416   if (expr2 == error_mark_node)
3417     return error_mark_node;
3418
3419   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3420 }
3421
3422 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3423
3424 tree
3425 build_c_cast (tree type, tree expr)
3426 {
3427   tree value = expr;
3428
3429   if (type == error_mark_node || expr == error_mark_node)
3430     return error_mark_node;
3431
3432   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3433      only in <protocol> qualifications.  But when constructing cast expressions,
3434      the protocols do matter and must be kept around.  */
3435   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3436     return build1 (NOP_EXPR, type, expr);
3437
3438   type = TYPE_MAIN_VARIANT (type);
3439
3440   if (TREE_CODE (type) == ARRAY_TYPE)
3441     {
3442       error ("cast specifies array type");
3443       return error_mark_node;
3444     }
3445
3446   if (TREE_CODE (type) == FUNCTION_TYPE)
3447     {
3448       error ("cast specifies function type");
3449       return error_mark_node;
3450     }
3451
3452   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3453     {
3454       if (pedantic)
3455         {
3456           if (TREE_CODE (type) == RECORD_TYPE
3457               || TREE_CODE (type) == UNION_TYPE)
3458             pedwarn ("ISO C forbids casting nonscalar to the same type");
3459         }
3460     }
3461   else if (TREE_CODE (type) == UNION_TYPE)
3462     {
3463       tree field;
3464
3465       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3466         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3467                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3468           break;
3469
3470       if (field)
3471         {
3472           tree t;
3473
3474           if (pedantic)
3475             pedwarn ("ISO C forbids casts to union type");
3476           t = digest_init (type,
3477                            build_constructor_single (type, field, value),
3478                            true, 0);
3479           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3480           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3481           return t;
3482         }
3483       error ("cast to union type from type not present in union");
3484       return error_mark_node;
3485     }
3486   else
3487     {
3488       tree otype, ovalue;
3489
3490       if (type == void_type_node)
3491         return build1 (CONVERT_EXPR, type, value);
3492
3493       otype = TREE_TYPE (value);
3494
3495       /* Optionally warn about potentially worrisome casts.  */
3496
3497       if (warn_cast_qual
3498           && TREE_CODE (type) == POINTER_TYPE
3499           && TREE_CODE (otype) == POINTER_TYPE)
3500         {
3501           tree in_type = type;
3502           tree in_otype = otype;
3503           int added = 0;
3504           int discarded = 0;
3505
3506           /* Check that the qualifiers on IN_TYPE are a superset of
3507              the qualifiers of IN_OTYPE.  The outermost level of
3508              POINTER_TYPE nodes is uninteresting and we stop as soon
3509              as we hit a non-POINTER_TYPE node on either type.  */
3510           do
3511             {
3512               in_otype = TREE_TYPE (in_otype);
3513               in_type = TREE_TYPE (in_type);
3514
3515               /* GNU C allows cv-qualified function types.  'const'
3516                  means the function is very pure, 'volatile' means it
3517                  can't return.  We need to warn when such qualifiers
3518                  are added, not when they're taken away.  */
3519               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3520                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3521                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3522               else
3523                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3524             }
3525           while (TREE_CODE (in_type) == POINTER_TYPE
3526                  && TREE_CODE (in_otype) == POINTER_TYPE);
3527
3528           if (added)
3529             warning (0, "cast adds new qualifiers to function type");
3530
3531           if (discarded)
3532             /* There are qualifiers present in IN_OTYPE that are not
3533                present in IN_TYPE.  */
3534             warning (0, "cast discards qualifiers from pointer target type");
3535         }
3536
3537       /* Warn about possible alignment problems.  */
3538       if (STRICT_ALIGNMENT
3539           && TREE_CODE (type) == POINTER_TYPE
3540           && TREE_CODE (otype) == POINTER_TYPE
3541           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3542           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3543           /* Don't warn about opaque types, where the actual alignment
3544              restriction is unknown.  */
3545           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3546                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3547                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3548           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3549         warning (OPT_Wcast_align,
3550                  "cast increases required alignment of target type");
3551
3552       if (TREE_CODE (type) == INTEGER_TYPE
3553           && TREE_CODE (otype) == POINTER_TYPE
3554           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3555       /* Unlike conversion of integers to pointers, where the
3556          warning is disabled for converting constants because
3557          of cases such as SIG_*, warn about converting constant
3558          pointers to integers. In some cases it may cause unwanted
3559          sign extension, and a warning is appropriate.  */
3560         warning (OPT_Wpointer_to_int_cast,
3561                  "cast from pointer to integer of different size");
3562
3563       if (TREE_CODE (value) == CALL_EXPR
3564           && TREE_CODE (type) != TREE_CODE (otype))
3565         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3566                  "to non-matching type %qT", otype, type);
3567
3568       if (TREE_CODE (type) == POINTER_TYPE
3569           && TREE_CODE (otype) == INTEGER_TYPE
3570           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3571           /* Don't warn about converting any constant.  */
3572           && !TREE_CONSTANT (value))
3573         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3574                  "of different size");
3575
3576       strict_aliasing_warning (otype, type, expr);
3577
3578       /* If pedantic, warn for conversions between function and object
3579          pointer types, except for converting a null pointer constant
3580          to function pointer type.  */
3581       if (pedantic
3582           && TREE_CODE (type) == POINTER_TYPE
3583           && TREE_CODE (otype) == POINTER_TYPE
3584           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3585           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3586         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3587
3588       if (pedantic
3589           && TREE_CODE (type) == POINTER_TYPE
3590           && TREE_CODE (otype) == POINTER_TYPE
3591           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3592           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3593           && !null_pointer_constant_p (value))
3594         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3595
3596       ovalue = value;
3597       value = convert (type, value);
3598
3599       /* Ignore any integer overflow caused by the cast.  */
3600       if (TREE_CODE (value) == INTEGER_CST)
3601         {
3602           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3603             {
3604               if (!TREE_OVERFLOW (value))
3605                 {
3606                   /* Avoid clobbering a shared constant.  */
3607                   value = copy_node (value);
3608                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3609                 }
3610             }
3611           else if (TREE_OVERFLOW (value))
3612             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3613             value = build_int_cst_wide (TREE_TYPE (value),
3614                                         TREE_INT_CST_LOW (value),
3615                                         TREE_INT_CST_HIGH (value));
3616         }
3617     }
3618
3619   /* Don't let a cast be an lvalue.  */
3620   if (value == expr)
3621     value = non_lvalue (value);
3622
3623   return value;
3624 }
3625
3626 /* Interpret a cast of expression EXPR to type TYPE.  */
3627 tree
3628 c_cast_expr (struct c_type_name *type_name, tree expr)
3629 {
3630   tree type;
3631   int saved_wsp = warn_strict_prototypes;
3632
3633   /* This avoids warnings about unprototyped casts on
3634      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3635   if (TREE_CODE (expr) == INTEGER_CST)
3636     warn_strict_prototypes = 0;
3637   type = groktypename (type_name);
3638   warn_strict_prototypes = saved_wsp;
3639
3640   return build_c_cast (type, expr);
3641 }
3642 \f
3643 /* Build an assignment expression of lvalue LHS from value RHS.
3644    MODIFYCODE is the code for a binary operator that we use
3645    to combine the old value of LHS with RHS to get the new value.
3646    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3647
3648 tree
3649 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3650 {
3651   tree result;
3652   tree newrhs;
3653   tree lhstype = TREE_TYPE (lhs);
3654   tree olhstype = lhstype;
3655
3656   /* Types that aren't fully specified cannot be used in assignments.  */
3657   lhs = require_complete_type (lhs);
3658
3659   /* Avoid duplicate error messages from operands that had errors.  */
3660   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3661     return error_mark_node;
3662
3663   if (!lvalue_or_else (lhs, lv_assign))
3664     return error_mark_node;
3665
3666   STRIP_TYPE_NOPS (rhs);
3667
3668   newrhs = rhs;
3669
3670   /* If a binary op has been requested, combine the old LHS value with the RHS
3671      producing the value we should actually store into the LHS.  */
3672
3673   if (modifycode != NOP_EXPR)
3674     {
3675       lhs = stabilize_reference (lhs);
3676       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3677     }
3678
3679   /* Give an error for storing in something that is 'const'.  */
3680
3681   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3682       || ((TREE_CODE (lhstype) == RECORD_TYPE
3683            || TREE_CODE (lhstype) == UNION_TYPE)
3684           && C_TYPE_FIELDS_READONLY (lhstype)))
3685     {
3686       readonly_error (lhs, lv_assign);
3687       return error_mark_node;
3688     }
3689
3690   /* If storing into a structure or union member,
3691      it has probably been given type `int'.
3692      Compute the type that would go with
3693      the actual amount of storage the member occupies.  */
3694
3695   if (TREE_CODE (lhs) == COMPONENT_REF
3696       && (TREE_CODE (lhstype) == INTEGER_TYPE
3697           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3698           || TREE_CODE (lhstype) == REAL_TYPE
3699           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3700     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3701
3702   /* If storing in a field that is in actuality a short or narrower than one,
3703      we must store in the field in its actual type.  */
3704
3705   if (lhstype != TREE_TYPE (lhs))
3706     {
3707       lhs = copy_node (lhs);
3708       TREE_TYPE (lhs) = lhstype;
3709     }
3710
3711   /* Convert new value to destination type.  */
3712
3713   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3714                                    NULL_TREE, NULL_TREE, 0);
3715   if (TREE_CODE (newrhs) == ERROR_MARK)
3716     return error_mark_node;
3717
3718   /* Emit ObjC write barrier, if necessary.  */
3719   if (c_dialect_objc () && flag_objc_gc)
3720     {
3721       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3722       if (result)
3723         return result;
3724     }
3725
3726   /* Scan operands.  */
3727
3728   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3729   TREE_SIDE_EFFECTS (result) = 1;
3730
3731   /* If we got the LHS in a different type for storing in,
3732      convert the result back to the nominal type of LHS
3733      so that the value we return always has the same type
3734      as the LHS argument.  */
3735
3736   if (olhstype == TREE_TYPE (result))
3737     return result;
3738   return convert_for_assignment (olhstype, result, ic_assign,
3739                                  NULL_TREE, NULL_TREE, 0);
3740 }
3741 \f
3742 /* Convert value RHS to type TYPE as preparation for an assignment
3743    to an lvalue of type TYPE.
3744    The real work of conversion is done by `convert'.
3745    The purpose of this function is to generate error messages
3746    for assignments that are not allowed in C.
3747    ERRTYPE says whether it is argument passing, assignment,
3748    initialization or return.
3749
3750    FUNCTION is a tree for the function being called.
3751    PARMNUM is the number of the argument, for printing in error messages.  */
3752
3753 static tree
3754 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3755                         tree fundecl, tree function, int parmnum)
3756 {
3757   enum tree_code codel = TREE_CODE (type);
3758   tree rhstype;
3759   enum tree_code coder;
3760   tree rname = NULL_TREE;
3761   bool objc_ok = false;
3762
3763   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3764     {
3765       tree selector;
3766       /* Change pointer to function to the function itself for
3767          diagnostics.  */
3768       if (TREE_CODE (function) == ADDR_EXPR
3769           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3770         function = TREE_OPERAND (function, 0);
3771
3772       /* Handle an ObjC selector specially for diagnostics.  */
3773       selector = objc_message_selector ();
3774       rname = function;
3775       if (selector && parmnum > 2)
3776         {
3777           rname = selector;
3778           parmnum -= 2;
3779         }
3780     }
3781
3782   /* This macro is used to emit diagnostics to ensure that all format
3783      strings are complete sentences, visible to gettext and checked at
3784      compile time.  */
3785 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3786   do {                                          \
3787     switch (errtype)                            \
3788       {                                         \
3789       case ic_argpass:                          \
3790         pedwarn (AR, parmnum, rname);           \
3791         break;                                  \
3792       case ic_argpass_nonproto:                 \
3793         warning (0, AR, parmnum, rname);                \
3794         break;                                  \
3795       case ic_assign:                           \
3796         pedwarn (AS);                           \
3797         break;                                  \
3798       case ic_init:                             \
3799         pedwarn (IN);                           \
3800         break;                                  \
3801       case ic_return:                           \
3802         pedwarn (RE);                           \
3803         break;                                  \
3804       default:                                  \
3805         gcc_unreachable ();                     \
3806       }                                         \
3807   } while (0)
3808
3809   STRIP_TYPE_NOPS (rhs);
3810
3811   if (optimize && TREE_CODE (rhs) == VAR_DECL
3812            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3813     rhs = decl_constant_value_for_broken_optimization (rhs);
3814
3815   rhstype = TREE_TYPE (rhs);
3816   coder = TREE_CODE (rhstype);
3817
3818   if (coder == ERROR_MARK)
3819     return error_mark_node;
3820
3821   if (c_dialect_objc ())
3822     {
3823       int parmno;
3824
3825       switch (errtype)
3826         {
3827         case ic_return:
3828           parmno = 0;
3829           break;
3830
3831         case ic_assign:
3832           parmno = -1;
3833           break;
3834
3835         case ic_init:
3836           parmno = -2;
3837           break;
3838
3839         default:
3840           parmno = parmnum;
3841           break;
3842         }
3843
3844       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3845     }
3846
3847   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3848     return rhs;
3849
3850   if (coder == VOID_TYPE)
3851     {
3852       /* Except for passing an argument to an unprototyped function,
3853          this is a constraint violation.  When passing an argument to
3854          an unprototyped function, it is compile-time undefined;
3855          making it a constraint in that case was rejected in
3856          DR#252.  */
3857       error ("void value not ignored as it ought to be");
3858       return error_mark_node;
3859     }
3860   /* A type converts to a reference to it.
3861      This code doesn't fully support references, it's just for the
3862      special case of va_start and va_copy.  */
3863   if (codel == REFERENCE_TYPE
3864       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3865     {
3866       if (!lvalue_p (rhs))
3867         {
3868           error ("cannot pass rvalue to reference parameter");
3869           return error_mark_node;
3870         }
3871       if (!c_mark_addressable (rhs))
3872         return error_mark_node;
3873       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3874
3875       /* We already know that these two types are compatible, but they
3876          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3877          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3878          likely to be va_list, a typedef to __builtin_va_list, which
3879          is different enough that it will cause problems later.  */
3880       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3881         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3882
3883       rhs = build1 (NOP_EXPR, type, rhs);
3884       return rhs;
3885     }
3886   /* Some types can interconvert without explicit casts.  */
3887   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3888            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
3889     return convert (type, rhs);
3890   /* Arithmetic types all interconvert, and enum is treated like int.  */
3891   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3892             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3893             || codel == BOOLEAN_TYPE)
3894            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3895                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3896                || coder == BOOLEAN_TYPE))
3897     return convert_and_check (type, rhs);
3898
3899   /* Aggregates in different TUs might need conversion.  */
3900   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
3901       && codel == coder
3902       && comptypes (type, rhstype))
3903     return convert_and_check (type, rhs);
3904
3905   /* Conversion to a transparent union from its member types.
3906      This applies only to function arguments.  */
3907   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3908       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3909     {
3910       tree memb, marginal_memb = NULL_TREE;
3911
3912       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3913         {
3914           tree memb_type = TREE_TYPE (memb);
3915
3916           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3917                          TYPE_MAIN_VARIANT (rhstype)))
3918             break;
3919
3920           if (TREE_CODE (memb_type) != POINTER_TYPE)
3921             continue;
3922
3923           if (coder == POINTER_TYPE)
3924             {
3925               tree ttl = TREE_TYPE (memb_type);
3926               tree ttr = TREE_TYPE (rhstype);
3927
3928               /* Any non-function converts to a [const][volatile] void *
3929                  and vice versa; otherwise, targets must be the same.
3930                  Meanwhile, the lhs target must have all the qualifiers of
3931                  the rhs.  */
3932               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3933                   || comp_target_types (memb_type, rhstype))
3934                 {
3935                   /* If this type won't generate any warnings, use it.  */
3936                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3937                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3938                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3939                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3940                              == TYPE_QUALS (ttr))
3941                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3942                              == TYPE_QUALS (ttl))))
3943                     break;
3944
3945                   /* Keep looking for a better type, but remember this one.  */
3946                   if (!marginal_memb)
3947                     marginal_memb = memb;
3948                 }
3949             }
3950
3951           /* Can convert integer zero to any pointer type.  */
3952           if (null_pointer_constant_p (rhs))
3953             {
3954               rhs = null_pointer_node;
3955               break;
3956             }
3957         }
3958
3959       if (memb || marginal_memb)
3960         {
3961           if (!memb)
3962             {
3963               /* We have only a marginally acceptable member type;
3964                  it needs a warning.  */
3965               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3966               tree ttr = TREE_TYPE (rhstype);
3967
3968               /* Const and volatile mean something different for function
3969                  types, so the usual warnings are not appropriate.  */
3970               if (TREE_CODE (ttr) == FUNCTION_TYPE
3971                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3972                 {
3973                   /* Because const and volatile on functions are
3974                      restrictions that say the function will not do
3975                      certain things, it is okay to use a const or volatile
3976                      function where an ordinary one is wanted, but not
3977                      vice-versa.  */
3978                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3979                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3980                                             "makes qualified function "
3981                                             "pointer from unqualified"),
3982                                          G_("assignment makes qualified "
3983                                             "function pointer from "
3984                                             "unqualified"),
3985                                          G_("initialization makes qualified "
3986                                             "function pointer from "
3987                                             "unqualified"),
3988                                          G_("return makes qualified function "
3989                                             "pointer from unqualified"));
3990                 }
3991               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3992                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3993                                         "qualifiers from pointer target type"),
3994                                      G_("assignment discards qualifiers "
3995                                         "from pointer target type"),
3996                                      G_("initialization discards qualifiers "
3997                                         "from pointer target type"),
3998                                      G_("return discards qualifiers from "
3999                                         "pointer target type"));
4000
4001               memb = marginal_memb;
4002             }
4003
4004           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
4005             pedwarn ("ISO C prohibits argument conversion to union type");
4006
4007           return build_constructor_single (type, memb, rhs);
4008         }
4009     }
4010
4011   /* Conversions among pointers */
4012   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4013            && (coder == codel))
4014     {
4015       tree ttl = TREE_TYPE (type);
4016       tree ttr = TREE_TYPE (rhstype);
4017       tree mvl = ttl;
4018       tree mvr = ttr;
4019       bool is_opaque_pointer;
4020       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4021
4022       if (TREE_CODE (mvl) != ARRAY_TYPE)
4023         mvl = TYPE_MAIN_VARIANT (mvl);
4024       if (TREE_CODE (mvr) != ARRAY_TYPE)
4025         mvr = TYPE_MAIN_VARIANT (mvr);
4026       /* Opaque pointers are treated like void pointers.  */
4027       is_opaque_pointer = (targetm.vector_opaque_p (type)
4028                            || targetm.vector_opaque_p (rhstype))
4029         && TREE_CODE (ttl) == VECTOR_TYPE
4030         && TREE_CODE (ttr) == VECTOR_TYPE;
4031
4032       /* C++ does not allow the implicit conversion void* -> T*.  However,
4033          for the purpose of reducing the number of false positives, we
4034          tolerate the special case of
4035
4036                 int *p = NULL;
4037
4038          where NULL is typically defined in C to be '(void *) 0'.  */
4039       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4040         warning (OPT_Wc___compat, "request for implicit conversion from "
4041                  "%qT to %qT not permitted in C++", rhstype, type);
4042
4043       /* Check if the right-hand side has a format attribute but the
4044          left-hand side doesn't.  */
4045       if (warn_missing_format_attribute
4046           && check_missing_format_attribute (type, rhstype))
4047         {
4048           switch (errtype)
4049           {
4050           case ic_argpass:
4051           case ic_argpass_nonproto:
4052             warning (OPT_Wmissing_format_attribute,
4053                      "argument %d of %qE might be "
4054                      "a candidate for a format attribute",
4055                      parmnum, rname);
4056             break;
4057           case ic_assign:
4058             warning (OPT_Wmissing_format_attribute,
4059                      "assignment left-hand side might be "
4060                      "a candidate for a format attribute");
4061             break;
4062           case ic_init:
4063             warning (OPT_Wmissing_format_attribute,
4064                      "initialization left-hand side might be "
4065                      "a candidate for a format attribute");
4066             break;
4067           case ic_return:
4068             warning (OPT_Wmissing_format_attribute,
4069                      "return type might be "
4070                      "a candidate for a format attribute");
4071             break;
4072           default:
4073             gcc_unreachable ();
4074           }
4075         }
4076
4077       /* Any non-function converts to a [const][volatile] void *
4078          and vice versa; otherwise, targets must be the same.
4079          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4080       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4081           || (target_cmp = comp_target_types (type, rhstype))
4082           || is_opaque_pointer
4083           || (c_common_unsigned_type (mvl)
4084               == c_common_unsigned_type (mvr)))
4085         {
4086           if (pedantic
4087               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4088                   ||
4089                   (VOID_TYPE_P (ttr)
4090                    && !null_pointer_constant_p (rhs)
4091                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4092             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4093                                     "%qE between function pointer "
4094                                     "and %<void *%>"),
4095                                  G_("ISO C forbids assignment between "
4096                                     "function pointer and %<void *%>"),
4097                                  G_("ISO C forbids initialization between "
4098                                     "function pointer and %<void *%>"),
4099                                  G_("ISO C forbids return between function "
4100                                     "pointer and %<void *%>"));
4101           /* Const and volatile mean something different for function types,
4102              so the usual warnings are not appropriate.  */
4103           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4104                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4105             {
4106               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4107                 {
4108                   /* Types differing only by the presence of the 'volatile'
4109                      qualifier are acceptable if the 'volatile' has been added
4110                      in by the Objective-C EH machinery.  */
4111                   if (!objc_type_quals_match (ttl, ttr))
4112                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4113                                             "qualifiers from pointer target type"),
4114                                          G_("assignment discards qualifiers "
4115                                             "from pointer target type"),
4116                                          G_("initialization discards qualifiers "
4117                                             "from pointer target type"),
4118                                          G_("return discards qualifiers from "
4119                                             "pointer target type"));
4120                 }
4121               /* If this is not a case of ignoring a mismatch in signedness,
4122                  no warning.  */
4123               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4124                        || target_cmp)
4125                 ;
4126               /* If there is a mismatch, do warn.  */
4127               else if (warn_pointer_sign)
4128                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4129                                         "%d of %qE differ in signedness"),
4130                                      G_("pointer targets in assignment "
4131                                         "differ in signedness"),
4132                                      G_("pointer targets in initialization "
4133                                         "differ in signedness"),
4134                                      G_("pointer targets in return differ "
4135                                         "in signedness"));
4136             }
4137           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4138                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4139             {
4140               /* Because const and volatile on functions are restrictions
4141                  that say the function will not do certain things,
4142                  it is okay to use a const or volatile function
4143                  where an ordinary one is wanted, but not vice-versa.  */
4144               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4145                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4146                                         "qualified function pointer "
4147                                         "from unqualified"),
4148                                      G_("assignment makes qualified function "
4149                                         "pointer from unqualified"),
4150                                      G_("initialization makes qualified "
4151                                         "function pointer from unqualified"),
4152                                      G_("return makes qualified function "
4153                                         "pointer from unqualified"));
4154             }
4155         }
4156       else
4157         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4158         if (!objc_ok)
4159           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4160                                   "incompatible pointer type"),
4161                                G_("assignment from incompatible pointer type"),
4162                                G_("initialization from incompatible "
4163                                   "pointer type"),
4164                                G_("return from incompatible pointer type"));
4165
4166       return convert (type, rhs);
4167     }
4168   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4169     {
4170       /* ??? This should not be an error when inlining calls to
4171          unprototyped functions.  */
4172       error ("invalid use of non-lvalue array");
4173       return error_mark_node;
4174     }
4175   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4176     {
4177       /* An explicit constant 0 can convert to a pointer,
4178          or one that results from arithmetic, even including
4179          a cast to integer type.  */
4180       if (!null_pointer_constant_p (rhs))
4181         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4182                                 "pointer from integer without a cast"),
4183                              G_("assignment makes pointer from integer "
4184                                 "without a cast"),
4185                              G_("initialization makes pointer from "
4186                                 "integer without a cast"),
4187                              G_("return makes pointer from integer "
4188                                 "without a cast"));
4189
4190       return convert (type, rhs);
4191     }
4192   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4193     {
4194       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4195                               "from pointer without a cast"),
4196                            G_("assignment makes integer from pointer "
4197                               "without a cast"),
4198                            G_("initialization makes integer from pointer "
4199                               "without a cast"),
4200                            G_("return makes integer from pointer "
4201                               "without a cast"));
4202       return convert (type, rhs);
4203     }
4204   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4205     return convert (type, rhs);
4206
4207   switch (errtype)
4208     {
4209     case ic_argpass:
4210     case ic_argpass_nonproto:
4211       /* ??? This should not be an error when inlining calls to
4212          unprototyped functions.  */
4213       error ("incompatible type for argument %d of %qE", parmnum, rname);
4214       break;
4215     case ic_assign:
4216       error ("incompatible types in assignment");
4217       break;
4218     case ic_init:
4219       error ("incompatible types in initialization");
4220       break;
4221     case ic_return:
4222       error ("incompatible types in return");
4223       break;
4224     default:
4225       gcc_unreachable ();
4226     }
4227
4228   return error_mark_node;
4229 }
4230
4231 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4232    is used for error and warning reporting and indicates which argument
4233    is being processed.  */
4234
4235 tree
4236 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4237 {
4238   tree ret, type;
4239
4240   /* If FN was prototyped at the call site, the value has been converted
4241      already in convert_arguments.
4242      However, we might see a prototype now that was not in place when
4243      the function call was seen, so check that the VALUE actually matches
4244      PARM before taking an early exit.  */
4245   if (!value
4246       || (TYPE_ARG_TYPES (TREE_TYPE (fn))
4247           && (TYPE_MAIN_VARIANT (TREE_TYPE (parm))
4248               == TYPE_MAIN_VARIANT (TREE_TYPE (value)))))
4249     return value;
4250
4251   type = TREE_TYPE (parm);
4252   ret = convert_for_assignment (type, value,
4253                                 ic_argpass_nonproto, fn,
4254                                 fn, argnum);
4255   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4256       && INTEGRAL_TYPE_P (type)
4257       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4258     ret = default_conversion (ret);
4259   return ret;
4260 }
4261 \f
4262 /* If VALUE is a compound expr all of whose expressions are constant, then
4263    return its value.  Otherwise, return error_mark_node.
4264
4265    This is for handling COMPOUND_EXPRs as initializer elements
4266    which is allowed with a warning when -pedantic is specified.  */
4267
4268 static tree
4269 valid_compound_expr_initializer (tree value, tree endtype)
4270 {
4271   if (TREE_CODE (value) == COMPOUND_EXPR)
4272     {
4273       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4274           == error_mark_node)
4275         return error_mark_node;
4276       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4277                                               endtype);
4278     }
4279   else if (!initializer_constant_valid_p (value, endtype))
4280     return error_mark_node;
4281   else
4282     return value;
4283 }
4284 \f
4285 /* Perform appropriate conversions on the initial value of a variable,
4286    store it in the declaration DECL,
4287    and print any error messages that are appropriate.
4288    If the init is invalid, store an ERROR_MARK.  */
4289
4290 void
4291 store_init_value (tree decl, tree init)
4292 {
4293   tree value, type;
4294
4295   /* If variable's type was invalidly declared, just ignore it.  */
4296
4297   type = TREE_TYPE (decl);
4298   if (TREE_CODE (type) == ERROR_MARK)
4299     return;
4300
4301   /* Digest the specified initializer into an expression.  */
4302
4303   value = digest_init (type, init, true, TREE_STATIC (decl));
4304
4305   /* Store the expression if valid; else report error.  */
4306
4307   if (!in_system_header
4308       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4309     warning (OPT_Wtraditional, "traditional C rejects automatic "
4310              "aggregate initialization");
4311
4312   DECL_INITIAL (decl) = value;
4313
4314   /* ANSI wants warnings about out-of-range constant initializers.  */
4315   STRIP_TYPE_NOPS (value);
4316   if (TREE_STATIC (decl))
4317     constant_expression_warning (value);
4318
4319   /* Check if we need to set array size from compound literal size.  */
4320   if (TREE_CODE (type) == ARRAY_TYPE
4321       && TYPE_DOMAIN (type) == 0
4322       && value != error_mark_node)
4323     {
4324       tree inside_init = init;
4325
4326       STRIP_TYPE_NOPS (inside_init);
4327       inside_init = fold (inside_init);
4328
4329       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4330         {
4331           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4332
4333           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4334             {
4335               /* For int foo[] = (int [3]){1}; we need to set array size
4336                  now since later on array initializer will be just the
4337                  brace enclosed list of the compound literal.  */
4338               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4339               TREE_TYPE (decl) = type;
4340               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4341               layout_type (type);
4342               layout_decl (cldecl, 0);
4343             }
4344         }
4345     }
4346 }
4347 \f
4348 /* Methods for storing and printing names for error messages.  */
4349
4350 /* Implement a spelling stack that allows components of a name to be pushed
4351    and popped.  Each element on the stack is this structure.  */
4352
4353 struct spelling
4354 {
4355   int kind;
4356   union
4357     {
4358       unsigned HOST_WIDE_INT i;
4359       const char *s;
4360     } u;
4361 };
4362
4363 #define SPELLING_STRING 1
4364 #define SPELLING_MEMBER 2
4365 #define SPELLING_BOUNDS 3
4366
4367 static struct spelling *spelling;       /* Next stack element (unused).  */
4368 static struct spelling *spelling_base;  /* Spelling stack base.  */
4369 static int spelling_size;               /* Size of the spelling stack.  */
4370
4371 /* Macros to save and restore the spelling stack around push_... functions.
4372    Alternative to SAVE_SPELLING_STACK.  */
4373
4374 #define SPELLING_DEPTH() (spelling - spelling_base)
4375 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4376
4377 /* Push an element on the spelling stack with type KIND and assign VALUE
4378    to MEMBER.  */
4379
4380 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4381 {                                                                       \
4382   int depth = SPELLING_DEPTH ();                                        \
4383                                                                         \
4384   if (depth >= spelling_size)                                           \
4385     {                                                                   \
4386       spelling_size += 10;                                              \
4387       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4388                                   spelling_size);                       \
4389       RESTORE_SPELLING_DEPTH (depth);                                   \
4390     }                                                                   \
4391                                                                         \
4392   spelling->kind = (KIND);                                              \
4393   spelling->MEMBER = (VALUE);                                           \
4394   spelling++;                                                           \
4395 }
4396
4397 /* Push STRING on the stack.  Printed literally.  */
4398
4399 static void
4400 push_string (const char *string)
4401 {
4402   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4403 }
4404
4405 /* Push a member name on the stack.  Printed as '.' STRING.  */
4406
4407 static void
4408 push_member_name (tree decl)
4409 {
4410   const char *const string
4411     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4412   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4413 }
4414
4415 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4416
4417 static void
4418 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4419 {
4420   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4421 }
4422
4423 /* Compute the maximum size in bytes of the printed spelling.  */
4424
4425 static int
4426 spelling_length (void)
4427 {
4428   int size = 0;
4429   struct spelling *p;
4430
4431   for (p = spelling_base; p < spelling; p++)
4432     {
4433       if (p->kind == SPELLING_BOUNDS)
4434         size += 25;
4435       else
4436         size += strlen (p->u.s) + 1;
4437     }
4438
4439   return size;
4440 }
4441
4442 /* Print the spelling to BUFFER and return it.  */
4443
4444 static char *
4445 print_spelling (char *buffer)
4446 {
4447   char *d = buffer;
4448   struct spelling *p;
4449
4450   for (p = spelling_base; p < spelling; p++)
4451     if (p->kind == SPELLING_BOUNDS)
4452       {
4453         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4454         d += strlen (d);
4455       }
4456     else
4457       {
4458         const char *s;
4459         if (p->kind == SPELLING_MEMBER)
4460           *d++ = '.';
4461         for (s = p->u.s; (*d = *s++); d++)
4462           ;
4463       }
4464   *d++ = '\0';
4465   return buffer;
4466 }
4467
4468 /* Issue an error message for a bad initializer component.
4469    MSGID identifies the message.
4470    The component name is taken from the spelling stack.  */
4471
4472 void
4473 error_init (const char *msgid)
4474 {
4475   char *ofwhat;
4476
4477   error ("%s", _(msgid));
4478   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4479   if (*ofwhat)
4480     error ("(near initialization for %qs)", ofwhat);
4481 }
4482
4483 /* Issue a pedantic warning for a bad initializer component.
4484    MSGID identifies the message.
4485    The component name is taken from the spelling stack.  */
4486
4487 void
4488 pedwarn_init (const char *msgid)
4489 {
4490   char *ofwhat;
4491
4492   pedwarn ("%s", _(msgid));
4493   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4494   if (*ofwhat)
4495     pedwarn ("(near initialization for %qs)", ofwhat);
4496 }
4497
4498 /* Issue a warning for a bad initializer component.
4499    MSGID identifies the message.
4500    The component name is taken from the spelling stack.  */
4501
4502 static void
4503 warning_init (const char *msgid)
4504 {
4505   char *ofwhat;
4506
4507   warning (0, "%s", _(msgid));
4508   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4509   if (*ofwhat)
4510     warning (0, "(near initialization for %qs)", ofwhat);
4511 }
4512 \f
4513 /* If TYPE is an array type and EXPR is a parenthesized string
4514    constant, warn if pedantic that EXPR is being used to initialize an
4515    object of type TYPE.  */
4516
4517 void
4518 maybe_warn_string_init (tree type, struct c_expr expr)
4519 {
4520   if (pedantic
4521       && TREE_CODE (type) == ARRAY_TYPE
4522       && TREE_CODE (expr.value) == STRING_CST
4523       && expr.original_code != STRING_CST)
4524     pedwarn_init ("array initialized from parenthesized string constant");
4525 }
4526
4527 /* Digest the parser output INIT as an initializer for type TYPE.
4528    Return a C expression of type TYPE to represent the initial value.
4529
4530    If INIT is a string constant, STRICT_STRING is true if it is
4531    unparenthesized or we should not warn here for it being parenthesized.
4532    For other types of INIT, STRICT_STRING is not used.
4533
4534    REQUIRE_CONSTANT requests an error if non-constant initializers or
4535    elements are seen.  */
4536
4537 static tree
4538 digest_init (tree type, tree init, bool strict_string, int require_constant)
4539 {
4540   enum tree_code code = TREE_CODE (type);
4541   tree inside_init = init;
4542
4543   if (type == error_mark_node
4544       || !init
4545       || init == error_mark_node
4546       || TREE_TYPE (init) == error_mark_node)
4547     return error_mark_node;
4548
4549   STRIP_TYPE_NOPS (inside_init);
4550
4551   inside_init = fold (inside_init);
4552
4553   /* Initialization of an array of chars from a string constant
4554      optionally enclosed in braces.  */
4555
4556   if (code == ARRAY_TYPE && inside_init
4557       && TREE_CODE (inside_init) == STRING_CST)
4558     {
4559       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4560       /* Note that an array could be both an array of character type
4561          and an array of wchar_t if wchar_t is signed char or unsigned
4562          char.  */
4563       bool char_array = (typ1 == char_type_node
4564                          || typ1 == signed_char_type_node
4565                          || typ1 == unsigned_char_type_node);
4566       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4567       if (char_array || wchar_array)
4568         {
4569           struct c_expr expr;
4570           bool char_string;
4571           expr.value = inside_init;
4572           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4573           maybe_warn_string_init (type, expr);
4574
4575           char_string
4576             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4577                == char_type_node);
4578
4579           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4580                          TYPE_MAIN_VARIANT (type)))
4581             return inside_init;
4582
4583           if (!wchar_array && !char_string)
4584             {
4585               error_init ("char-array initialized from wide string");
4586               return error_mark_node;
4587             }
4588           if (char_string && !char_array)
4589             {
4590               error_init ("wchar_t-array initialized from non-wide string");
4591               return error_mark_node;
4592             }
4593
4594           TREE_TYPE (inside_init) = type;
4595           if (TYPE_DOMAIN (type) != 0
4596               && TYPE_SIZE (type) != 0
4597               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4598               /* Subtract 1 (or sizeof (wchar_t))
4599                  because it's ok to ignore the terminating null char
4600                  that is counted in the length of the constant.  */
4601               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4602                                        TREE_STRING_LENGTH (inside_init)
4603                                        - ((TYPE_PRECISION (typ1)
4604                                            != TYPE_PRECISION (char_type_node))
4605                                           ? (TYPE_PRECISION (wchar_type_node)
4606                                              / BITS_PER_UNIT)
4607                                           : 1)))
4608             pedwarn_init ("initializer-string for array of chars is too long");
4609
4610           return inside_init;
4611         }
4612       else if (INTEGRAL_TYPE_P (typ1))
4613         {
4614           error_init ("array of inappropriate type initialized "
4615                       "from string constant");
4616           return error_mark_node;
4617         }
4618     }
4619
4620   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4621      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4622      below and handle as a constructor.  */
4623   if (code == VECTOR_TYPE
4624       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4625       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4626       && TREE_CONSTANT (inside_init))
4627     {
4628       if (TREE_CODE (inside_init) == VECTOR_CST
4629           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4630                         TYPE_MAIN_VARIANT (type)))
4631         return inside_init;
4632
4633       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4634         {
4635           unsigned HOST_WIDE_INT ix;
4636           tree value;
4637           bool constant_p = true;
4638
4639           /* Iterate through elements and check if all constructor
4640              elements are *_CSTs.  */
4641           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4642             if (!CONSTANT_CLASS_P (value))
4643               {
4644                 constant_p = false;
4645                 break;
4646               }
4647
4648           if (constant_p)
4649             return build_vector_from_ctor (type,
4650                                            CONSTRUCTOR_ELTS (inside_init));
4651         }
4652     }
4653
4654   /* Any type can be initialized
4655      from an expression of the same type, optionally with braces.  */
4656
4657   if (inside_init && TREE_TYPE (inside_init) != 0
4658       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4659                      TYPE_MAIN_VARIANT (type))
4660           || (code == ARRAY_TYPE
4661               && comptypes (TREE_TYPE (inside_init), type))
4662           || (code == VECTOR_TYPE
4663               && comptypes (TREE_TYPE (inside_init), type))
4664           || (code == POINTER_TYPE
4665               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4666               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4667                             TREE_TYPE (type)))))
4668     {
4669       if (code == POINTER_TYPE)
4670         {
4671           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4672             {
4673               if (TREE_CODE (inside_init) == STRING_CST
4674                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4675                 inside_init = array_to_pointer_conversion (inside_init);
4676               else
4677                 {
4678                   error_init ("invalid use of non-lvalue array");
4679                   return error_mark_node;
4680                 }
4681             }
4682         }
4683
4684       if (code == VECTOR_TYPE)
4685         /* Although the types are compatible, we may require a
4686            conversion.  */
4687         inside_init = convert (type, inside_init);
4688
4689       if (require_constant
4690           && (code == VECTOR_TYPE || !flag_isoc99)
4691           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4692         {
4693           /* As an extension, allow initializing objects with static storage
4694              duration with compound literals (which are then treated just as
4695              the brace enclosed list they contain).  Also allow this for
4696              vectors, as we can only assign them with compound literals.  */
4697           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4698           inside_init = DECL_INITIAL (decl);
4699         }
4700
4701       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4702           && TREE_CODE (inside_init) != CONSTRUCTOR)
4703         {
4704           error_init ("array initialized from non-constant array expression");
4705           return error_mark_node;
4706         }
4707
4708       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4709         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4710
4711       /* Compound expressions can only occur here if -pedantic or
4712          -pedantic-errors is specified.  In the later case, we always want
4713          an error.  In the former case, we simply want a warning.  */
4714       if (require_constant && pedantic
4715           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4716         {
4717           inside_init
4718             = valid_compound_expr_initializer (inside_init,
4719                                                TREE_TYPE (inside_init));
4720           if (inside_init == error_mark_node)
4721             error_init ("initializer element is not constant");
4722           else
4723             pedwarn_init ("initializer element is not constant");
4724           if (flag_pedantic_errors)
4725             inside_init = error_mark_node;
4726         }
4727       else if (require_constant
4728                && !initializer_constant_valid_p (inside_init,
4729                                                  TREE_TYPE (inside_init)))
4730         {
4731           error_init ("initializer element is not constant");
4732           inside_init = error_mark_node;
4733         }
4734
4735       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4736       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4737         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4738                                               NULL_TREE, 0);
4739       return inside_init;
4740     }
4741
4742   /* Handle scalar types, including conversions.  */
4743
4744   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4745       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4746       || code == VECTOR_TYPE)
4747     {
4748       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4749           && (TREE_CODE (init) == STRING_CST
4750               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4751         init = array_to_pointer_conversion (init);
4752       inside_init
4753         = convert_for_assignment (type, init, ic_init,
4754                                   NULL_TREE, NULL_TREE, 0);
4755
4756       /* Check to see if we have already given an error message.  */
4757       if (inside_init == error_mark_node)
4758         ;
4759       else if (require_constant && !TREE_CONSTANT (inside_init))
4760         {
4761           error_init ("initializer element is not constant");
4762           inside_init = error_mark_node;
4763         }
4764       else if (require_constant
4765                && !initializer_constant_valid_p (inside_init,
4766                                                  TREE_TYPE (inside_init)))
4767         {
4768           error_init ("initializer element is not computable at load time");
4769           inside_init = error_mark_node;
4770         }
4771
4772       return inside_init;
4773     }
4774
4775   /* Come here only for records and arrays.  */
4776
4777   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4778     {
4779       error_init ("variable-sized object may not be initialized");
4780       return error_mark_node;
4781     }
4782
4783   error_init ("invalid initializer");
4784   return error_mark_node;
4785 }
4786 \f
4787 /* Handle initializers that use braces.  */
4788
4789 /* Type of object we are accumulating a constructor for.
4790    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4791 static tree constructor_type;
4792
4793 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4794    left to fill.  */
4795 static tree constructor_fields;
4796
4797 /* For an ARRAY_TYPE, this is the specified index
4798    at which to store the next element we get.  */
4799 static tree constructor_index;
4800
4801 /* For an ARRAY_TYPE, this is the maximum index.  */
4802 static tree constructor_max_index;
4803
4804 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4805 static tree constructor_unfilled_fields;
4806
4807 /* For an ARRAY_TYPE, this is the index of the first element
4808    not yet written out.  */
4809 static tree constructor_unfilled_index;
4810
4811 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4812    This is so we can generate gaps between fields, when appropriate.  */
4813 static tree constructor_bit_index;
4814
4815 /* If we are saving up the elements rather than allocating them,
4816    this is the list of elements so far (in reverse order,
4817    most recent first).  */
4818 static VEC(constructor_elt,gc) *constructor_elements;
4819
4820 /* 1 if constructor should be incrementally stored into a constructor chain,
4821    0 if all the elements should be kept in AVL tree.  */
4822 static int constructor_incremental;
4823
4824 /* 1 if so far this constructor's elements are all compile-time constants.  */
4825 static int constructor_constant;
4826
4827 /* 1 if so far this constructor's elements are all valid address constants.  */
4828 static int constructor_simple;
4829
4830 /* 1 if this constructor is erroneous so far.  */
4831 static int constructor_erroneous;
4832
4833 /* Structure for managing pending initializer elements, organized as an
4834    AVL tree.  */
4835
4836 struct init_node
4837 {
4838   struct init_node *left, *right;
4839   struct init_node *parent;
4840   int balance;
4841   tree purpose;
4842   tree value;
4843 };
4844
4845 /* Tree of pending elements at this constructor level.
4846    These are elements encountered out of order
4847    which belong at places we haven't reached yet in actually
4848    writing the output.
4849    Will never hold tree nodes across GC runs.  */
4850 static struct init_node *constructor_pending_elts;
4851
4852 /* The SPELLING_DEPTH of this constructor.  */
4853 static int constructor_depth;
4854
4855 /* DECL node for which an initializer is being read.
4856    0 means we are reading a constructor expression
4857    such as (struct foo) {...}.  */
4858 static tree constructor_decl;
4859
4860 /* Nonzero if this is an initializer for a top-level decl.  */
4861 static int constructor_top_level;
4862
4863 /* Nonzero if there were any member designators in this initializer.  */
4864 static int constructor_designated;
4865
4866 /* Nesting depth of designator list.  */
4867 static int designator_depth;
4868
4869 /* Nonzero if there were diagnosed errors in this designator list.  */
4870 static int designator_erroneous;
4871
4872 \f
4873 /* This stack has a level for each implicit or explicit level of
4874    structuring in the initializer, including the outermost one.  It
4875    saves the values of most of the variables above.  */
4876
4877 struct constructor_range_stack;
4878
4879 struct constructor_stack
4880 {
4881   struct constructor_stack *next;
4882   tree type;
4883   tree fields;
4884   tree index;
4885   tree max_index;
4886   tree unfilled_index;
4887   tree unfilled_fields;
4888   tree bit_index;
4889   VEC(constructor_elt,gc) *elements;
4890   struct init_node *pending_elts;
4891   int offset;
4892   int depth;
4893   /* If value nonzero, this value should replace the entire
4894      constructor at this level.  */
4895   struct c_expr replacement_value;
4896   struct constructor_range_stack *range_stack;
4897   char constant;
4898   char simple;
4899   char implicit;
4900   char erroneous;
4901   char outer;
4902   char incremental;
4903   char designated;
4904 };
4905
4906 static struct constructor_stack *constructor_stack;
4907
4908 /* This stack represents designators from some range designator up to
4909    the last designator in the list.  */
4910
4911 struct constructor_range_stack
4912 {
4913   struct constructor_range_stack *next, *prev;
4914   struct constructor_stack *stack;
4915   tree range_start;
4916   tree index;
4917   tree range_end;
4918   tree fields;
4919 };
4920
4921 static struct constructor_range_stack *constructor_range_stack;
4922
4923 /* This stack records separate initializers that are nested.
4924    Nested initializers can't happen in ANSI C, but GNU C allows them
4925    in cases like { ... (struct foo) { ... } ... }.  */
4926
4927 struct initializer_stack
4928 {
4929   struct initializer_stack *next;
4930   tree decl;
4931   struct constructor_stack *constructor_stack;
4932   struct constructor_range_stack *constructor_range_stack;
4933   VEC(constructor_elt,gc) *elements;
4934   struct spelling *spelling;
4935   struct spelling *spelling_base;
4936   int spelling_size;
4937   char top_level;
4938   char require_constant_value;
4939   char require_constant_elements;
4940 };
4941
4942 static struct initializer_stack *initializer_stack;
4943 \f
4944 /* Prepare to parse and output the initializer for variable DECL.  */
4945
4946 void
4947 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4948 {
4949   const char *locus;
4950   struct initializer_stack *p = XNEW (struct initializer_stack);
4951
4952   p->decl = constructor_decl;
4953   p->require_constant_value = require_constant_value;
4954   p->require_constant_elements = require_constant_elements;
4955   p->constructor_stack = constructor_stack;
4956   p->constructor_range_stack = constructor_range_stack;
4957   p->elements = constructor_elements;
4958   p->spelling = spelling;
4959   p->spelling_base = spelling_base;
4960   p->spelling_size = spelling_size;
4961   p->top_level = constructor_top_level;
4962   p->next = initializer_stack;
4963   initializer_stack = p;
4964
4965   constructor_decl = decl;
4966   constructor_designated = 0;
4967   constructor_top_level = top_level;
4968
4969   if (decl != 0 && decl != error_mark_node)
4970     {
4971       require_constant_value = TREE_STATIC (decl);
4972       require_constant_elements
4973         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4974            /* For a scalar, you can always use any value to initialize,
4975               even within braces.  */
4976            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4977                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4978                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4979                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4980       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4981     }
4982   else
4983     {
4984       require_constant_value = 0;
4985       require_constant_elements = 0;
4986       locus = "(anonymous)";
4987     }
4988
4989   constructor_stack = 0;
4990   constructor_range_stack = 0;
4991
4992   missing_braces_mentioned = 0;
4993
4994   spelling_base = 0;
4995   spelling_size = 0;
4996   RESTORE_SPELLING_DEPTH (0);
4997
4998   if (locus)
4999     push_string (locus);
5000 }
5001
5002 void
5003 finish_init (void)
5004 {
5005   struct initializer_stack *p = initializer_stack;
5006
5007   /* Free the whole constructor stack of this initializer.  */
5008   while (constructor_stack)
5009     {
5010       struct constructor_stack *q = constructor_stack;
5011       constructor_stack = q->next;
5012       free (q);
5013     }
5014
5015   gcc_assert (!constructor_range_stack);
5016
5017   /* Pop back to the data of the outer initializer (if any).  */
5018   free (spelling_base);
5019
5020   constructor_decl = p->decl;
5021   require_constant_value = p->require_constant_value;
5022   require_constant_elements = p->require_constant_elements;
5023   constructor_stack = p->constructor_stack;
5024   constructor_range_stack = p->constructor_range_stack;
5025   constructor_elements = p->elements;
5026   spelling = p->spelling;
5027   spelling_base = p->spelling_base;
5028   spelling_size = p->spelling_size;
5029   constructor_top_level = p->top_level;
5030   initializer_stack = p->next;
5031   free (p);
5032 }
5033 \f
5034 /* Call here when we see the initializer is surrounded by braces.
5035    This is instead of a call to push_init_level;
5036    it is matched by a call to pop_init_level.
5037
5038    TYPE is the type to initialize, for a constructor expression.
5039    For an initializer for a decl, TYPE is zero.  */
5040
5041 void
5042 really_start_incremental_init (tree type)
5043 {
5044   struct constructor_stack *p = XNEW (struct constructor_stack);
5045
5046   if (type == 0)
5047     type = TREE_TYPE (constructor_decl);
5048
5049   if (targetm.vector_opaque_p (type))
5050     error ("opaque vector types cannot be initialized");
5051
5052   p->type = constructor_type;
5053   p->fields = constructor_fields;
5054   p->index = constructor_index;
5055   p->max_index = constructor_max_index;
5056   p->unfilled_index = constructor_unfilled_index;
5057   p->unfilled_fields = constructor_unfilled_fields;
5058   p->bit_index = constructor_bit_index;
5059   p->elements = constructor_elements;
5060   p->constant = constructor_constant;
5061   p->simple = constructor_simple;
5062   p->erroneous = constructor_erroneous;
5063   p->pending_elts = constructor_pending_elts;
5064   p->depth = constructor_depth;
5065   p->replacement_value.value = 0;
5066   p->replacement_value.original_code = ERROR_MARK;
5067   p->implicit = 0;
5068   p->range_stack = 0;
5069   p->outer = 0;
5070   p->incremental = constructor_incremental;
5071   p->designated = constructor_designated;
5072   p->next = 0;
5073   constructor_stack = p;
5074
5075   constructor_constant = 1;
5076   constructor_simple = 1;
5077   constructor_depth = SPELLING_DEPTH ();
5078   constructor_elements = 0;
5079   constructor_pending_elts = 0;
5080   constructor_type = type;
5081   constructor_incremental = 1;
5082   constructor_designated = 0;
5083   designator_depth = 0;
5084   designator_erroneous = 0;
5085
5086   if (TREE_CODE (constructor_type) == RECORD_TYPE
5087       || TREE_CODE (constructor_type) == UNION_TYPE)
5088     {
5089       constructor_fields = TYPE_FIELDS (constructor_type);
5090       /* Skip any nameless bit fields at the beginning.  */
5091       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5092              && DECL_NAME (constructor_fields) == 0)
5093         constructor_fields = TREE_CHAIN (constructor_fields);
5094
5095       constructor_unfilled_fields = constructor_fields;
5096       constructor_bit_index = bitsize_zero_node;
5097     }
5098   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5099     {
5100       if (TYPE_DOMAIN (constructor_type))
5101         {
5102           constructor_max_index
5103             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5104
5105           /* Detect non-empty initializations of zero-length arrays.  */
5106           if (constructor_max_index == NULL_TREE
5107               && TYPE_SIZE (constructor_type))
5108             constructor_max_index = build_int_cst (NULL_TREE, -1);
5109
5110           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5111              to initialize VLAs will cause a proper error; avoid tree
5112              checking errors as well by setting a safe value.  */
5113           if (constructor_max_index
5114               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5115             constructor_max_index = build_int_cst (NULL_TREE, -1);
5116
5117           constructor_index
5118             = convert (bitsizetype,
5119                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5120         }
5121       else
5122         {
5123           constructor_index = bitsize_zero_node;
5124           constructor_max_index = NULL_TREE;
5125         }
5126
5127       constructor_unfilled_index = constructor_index;
5128     }
5129   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5130     {
5131       /* Vectors are like simple fixed-size arrays.  */
5132       constructor_max_index =
5133         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5134       constructor_index = bitsize_zero_node;
5135       constructor_unfilled_index = constructor_index;
5136     }
5137   else
5138     {
5139       /* Handle the case of int x = {5}; */
5140       constructor_fields = constructor_type;
5141       constructor_unfilled_fields = constructor_type;
5142     }
5143 }
5144 \f
5145 /* Push down into a subobject, for initialization.
5146    If this is for an explicit set of braces, IMPLICIT is 0.
5147    If it is because the next element belongs at a lower level,
5148    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5149
5150 void
5151 push_init_level (int implicit)
5152 {
5153   struct constructor_stack *p;
5154   tree value = NULL_TREE;
5155
5156   /* If we've exhausted any levels that didn't have braces,
5157      pop them now.  If implicit == 1, this will have been done in
5158      process_init_element; do not repeat it here because in the case
5159      of excess initializers for an empty aggregate this leads to an
5160      infinite cycle of popping a level and immediately recreating
5161      it.  */
5162   if (implicit != 1)
5163     {
5164       while (constructor_stack->implicit)
5165         {
5166           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5167                || TREE_CODE (constructor_type) == UNION_TYPE)
5168               && constructor_fields == 0)
5169             process_init_element (pop_init_level (1));
5170           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5171                    && constructor_max_index
5172                    && tree_int_cst_lt (constructor_max_index,
5173                                        constructor_index))
5174             process_init_element (pop_init_level (1));
5175           else
5176             break;
5177         }
5178     }
5179
5180   /* Unless this is an explicit brace, we need to preserve previous
5181      content if any.  */
5182   if (implicit)
5183     {
5184       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5185            || TREE_CODE (constructor_type) == UNION_TYPE)
5186           && constructor_fields)
5187         value = find_init_member (constructor_fields);
5188       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5189         value = find_init_member (constructor_index);
5190     }
5191
5192   p = XNEW (struct constructor_stack);
5193   p->type = constructor_type;
5194   p->fields = constructor_fields;
5195   p->index = constructor_index;
5196   p->max_index = constructor_max_index;
5197   p->unfilled_index = constructor_unfilled_index;
5198   p->unfilled_fields = constructor_unfilled_fields;
5199   p->bit_index = constructor_bit_index;
5200   p->elements = constructor_elements;
5201   p->constant = constructor_constant;
5202   p->simple = constructor_simple;
5203   p->erroneous = constructor_erroneous;
5204   p->pending_elts = constructor_pending_elts;
5205   p->depth = constructor_depth;
5206   p->replacement_value.value = 0;
5207   p->replacement_value.original_code = ERROR_MARK;
5208   p->implicit = implicit;
5209   p->outer = 0;
5210   p->incremental = constructor_incremental;
5211   p->designated = constructor_designated;
5212   p->next = constructor_stack;
5213   p->range_stack = 0;
5214   constructor_stack = p;
5215
5216   constructor_constant = 1;
5217   constructor_simple = 1;
5218   constructor_depth = SPELLING_DEPTH ();
5219   constructor_elements = 0;
5220   constructor_incremental = 1;
5221   constructor_designated = 0;
5222   constructor_pending_elts = 0;
5223   if (!implicit)
5224     {
5225       p->range_stack = constructor_range_stack;
5226       constructor_range_stack = 0;
5227       designator_depth = 0;
5228       designator_erroneous = 0;
5229     }
5230
5231   /* Don't die if an entire brace-pair level is superfluous
5232      in the containing level.  */
5233   if (constructor_type == 0)
5234     ;
5235   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5236            || TREE_CODE (constructor_type) == UNION_TYPE)
5237     {
5238       /* Don't die if there are extra init elts at the end.  */
5239       if (constructor_fields == 0)
5240         constructor_type = 0;
5241       else
5242         {
5243           constructor_type = TREE_TYPE (constructor_fields);
5244           push_member_name (constructor_fields);
5245           constructor_depth++;
5246         }
5247     }
5248   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5249     {
5250       constructor_type = TREE_TYPE (constructor_type);
5251       push_array_bounds (tree_low_cst (constructor_index, 1));
5252       constructor_depth++;
5253     }
5254
5255   if (constructor_type == 0)
5256     {
5257       error_init ("extra brace group at end of initializer");
5258       constructor_fields = 0;
5259       constructor_unfilled_fields = 0;
5260       return;
5261     }
5262
5263   if (value && TREE_CODE (value) == CONSTRUCTOR)
5264     {
5265       constructor_constant = TREE_CONSTANT (value);
5266       constructor_simple = TREE_STATIC (value);
5267       constructor_elements = CONSTRUCTOR_ELTS (value);
5268       if (!VEC_empty (constructor_elt, constructor_elements)
5269           && (TREE_CODE (constructor_type) == RECORD_TYPE
5270               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5271         set_nonincremental_init ();
5272     }
5273
5274   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5275     {
5276       missing_braces_mentioned = 1;
5277       warning_init ("missing braces around initializer");
5278     }
5279
5280   if (TREE_CODE (constructor_type) == RECORD_TYPE
5281            || TREE_CODE (constructor_type) == UNION_TYPE)
5282     {
5283       constructor_fields = TYPE_FIELDS (constructor_type);
5284       /* Skip any nameless bit fields at the beginning.  */
5285       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5286              && DECL_NAME (constructor_fields) == 0)
5287         constructor_fields = TREE_CHAIN (constructor_fields);
5288
5289       constructor_unfilled_fields = constructor_fields;
5290       constructor_bit_index = bitsize_zero_node;
5291     }
5292   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5293     {
5294       /* Vectors are like simple fixed-size arrays.  */
5295       constructor_max_index =
5296         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5297       constructor_index = convert (bitsizetype, integer_zero_node);
5298       constructor_unfilled_index = constructor_index;
5299     }
5300   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5301     {
5302       if (TYPE_DOMAIN (constructor_type))
5303         {
5304           constructor_max_index
5305             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5306
5307           /* Detect non-empty initializations of zero-length arrays.  */
5308           if (constructor_max_index == NULL_TREE
5309               && TYPE_SIZE (constructor_type))
5310             constructor_max_index = build_int_cst (NULL_TREE, -1);
5311
5312           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5313              to initialize VLAs will cause a proper error; avoid tree
5314              checking errors as well by setting a safe value.  */
5315           if (constructor_max_index
5316               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5317             constructor_max_index = build_int_cst (NULL_TREE, -1);
5318
5319           constructor_index
5320             = convert (bitsizetype,
5321                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5322         }
5323       else
5324         constructor_index = bitsize_zero_node;
5325
5326       constructor_unfilled_index = constructor_index;
5327       if (value && TREE_CODE (value) == STRING_CST)
5328         {
5329           /* We need to split the char/wchar array into individual
5330              characters, so that we don't have to special case it
5331              everywhere.  */
5332           set_nonincremental_init_from_string (value);
5333         }
5334     }
5335   else
5336     {
5337       if (constructor_type != error_mark_node)
5338         warning_init ("braces around scalar initializer");
5339       constructor_fields = constructor_type;
5340       constructor_unfilled_fields = constructor_type;
5341     }
5342 }
5343
5344 /* At the end of an implicit or explicit brace level,
5345    finish up that level of constructor.  If a single expression
5346    with redundant braces initialized that level, return the
5347    c_expr structure for that expression.  Otherwise, the original_code
5348    element is set to ERROR_MARK.
5349    If we were outputting the elements as they are read, return 0 as the value
5350    from inner levels (process_init_element ignores that),
5351    but return error_mark_node as the value from the outermost level
5352    (that's what we want to put in DECL_INITIAL).
5353    Otherwise, return a CONSTRUCTOR expression as the value.  */
5354
5355 struct c_expr
5356 pop_init_level (int implicit)
5357 {
5358   struct constructor_stack *p;
5359   struct c_expr ret;
5360   ret.value = 0;
5361   ret.original_code = ERROR_MARK;
5362
5363   if (implicit == 0)
5364     {
5365       /* When we come to an explicit close brace,
5366          pop any inner levels that didn't have explicit braces.  */
5367       while (constructor_stack->implicit)
5368         process_init_element (pop_init_level (1));
5369
5370       gcc_assert (!constructor_range_stack);
5371     }
5372
5373   /* Now output all pending elements.  */
5374   constructor_incremental = 1;
5375   output_pending_init_elements (1);
5376
5377   p = constructor_stack;
5378
5379   /* Error for initializing a flexible array member, or a zero-length
5380      array member in an inappropriate context.  */
5381   if (constructor_type && constructor_fields
5382       && TREE_CODE (constructor_type) == ARRAY_TYPE
5383       && TYPE_DOMAIN (constructor_type)
5384       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5385     {
5386       /* Silently discard empty initializations.  The parser will
5387          already have pedwarned for empty brackets.  */
5388       if (integer_zerop (constructor_unfilled_index))
5389         constructor_type = NULL_TREE;
5390       else
5391         {
5392           gcc_assert (!TYPE_SIZE (constructor_type));
5393
5394           if (constructor_depth > 2)
5395             error_init ("initialization of flexible array member in a nested context");
5396           else if (pedantic)
5397             pedwarn_init ("initialization of a flexible array member");
5398
5399           /* We have already issued an error message for the existence
5400              of a flexible array member not at the end of the structure.
5401              Discard the initializer so that we do not die later.  */
5402           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5403             constructor_type = NULL_TREE;
5404         }
5405     }
5406
5407   /* Warn when some struct elements are implicitly initialized to zero.  */
5408   if (warn_missing_field_initializers
5409       && constructor_type
5410       && TREE_CODE (constructor_type) == RECORD_TYPE
5411       && constructor_unfilled_fields)
5412     {
5413         /* Do not warn for flexible array members or zero-length arrays.  */
5414         while (constructor_unfilled_fields
5415                && (!DECL_SIZE (constructor_unfilled_fields)
5416                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5417           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5418
5419         /* Do not warn if this level of the initializer uses member
5420            designators; it is likely to be deliberate.  */
5421         if (constructor_unfilled_fields && !constructor_designated)
5422           {
5423             push_member_name (constructor_unfilled_fields);
5424             warning_init ("missing initializer");
5425             RESTORE_SPELLING_DEPTH (constructor_depth);
5426           }
5427     }
5428
5429   /* Pad out the end of the structure.  */
5430   if (p->replacement_value.value)
5431     /* If this closes a superfluous brace pair,
5432        just pass out the element between them.  */
5433     ret = p->replacement_value;
5434   else if (constructor_type == 0)
5435     ;
5436   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5437            && TREE_CODE (constructor_type) != UNION_TYPE
5438            && TREE_CODE (constructor_type) != ARRAY_TYPE
5439            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5440     {
5441       /* A nonincremental scalar initializer--just return
5442          the element, after verifying there is just one.  */
5443       if (VEC_empty (constructor_elt,constructor_elements))
5444         {
5445           if (!constructor_erroneous)
5446             error_init ("empty scalar initializer");
5447           ret.value = error_mark_node;
5448         }
5449       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5450         {
5451           error_init ("extra elements in scalar initializer");
5452           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5453         }
5454       else
5455         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5456     }
5457   else
5458     {
5459       if (constructor_erroneous)
5460         ret.value = error_mark_node;
5461       else
5462         {
5463           ret.value = build_constructor (constructor_type,
5464                                          constructor_elements);
5465           if (constructor_constant)
5466             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5467           if (constructor_constant && constructor_simple)
5468             TREE_STATIC (ret.value) = 1;
5469         }
5470     }
5471
5472   constructor_type = p->type;
5473   constructor_fields = p->fields;
5474   constructor_index = p->index;
5475   constructor_max_index = p->max_index;
5476   constructor_unfilled_index = p->unfilled_index;
5477   constructor_unfilled_fields = p->unfilled_fields;
5478   constructor_bit_index = p->bit_index;
5479   constructor_elements = p->elements;
5480   constructor_constant = p->constant;
5481   constructor_simple = p->simple;
5482   constructor_erroneous = p->erroneous;
5483   constructor_incremental = p->incremental;
5484   constructor_designated = p->designated;
5485   constructor_pending_elts = p->pending_elts;
5486   constructor_depth = p->depth;
5487   if (!p->implicit)
5488     constructor_range_stack = p->range_stack;
5489   RESTORE_SPELLING_DEPTH (constructor_depth);
5490
5491   constructor_stack = p->next;
5492   free (p);
5493
5494   if (ret.value == 0 && constructor_stack == 0)
5495     ret.value = error_mark_node;
5496   return ret;
5497 }
5498
5499 /* Common handling for both array range and field name designators.
5500    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5501
5502 static int
5503 set_designator (int array)
5504 {
5505   tree subtype;
5506   enum tree_code subcode;
5507
5508   /* Don't die if an entire brace-pair level is superfluous
5509      in the containing level.  */
5510   if (constructor_type == 0)
5511     return 1;
5512
5513   /* If there were errors in this designator list already, bail out
5514      silently.  */
5515   if (designator_erroneous)
5516     return 1;
5517
5518   if (!designator_depth)
5519     {
5520       gcc_assert (!constructor_range_stack);
5521
5522       /* Designator list starts at the level of closest explicit
5523          braces.  */
5524       while (constructor_stack->implicit)
5525         process_init_element (pop_init_level (1));
5526       constructor_designated = 1;
5527       return 0;
5528     }
5529
5530   switch (TREE_CODE (constructor_type))
5531     {
5532     case  RECORD_TYPE:
5533     case  UNION_TYPE:
5534       subtype = TREE_TYPE (constructor_fields);
5535       if (subtype != error_mark_node)
5536         subtype = TYPE_MAIN_VARIANT (subtype);
5537       break;
5538     case ARRAY_TYPE:
5539       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5540       break;
5541     default:
5542       gcc_unreachable ();
5543     }
5544
5545   subcode = TREE_CODE (subtype);
5546   if (array && subcode != ARRAY_TYPE)
5547     {
5548       error_init ("array index in non-array initializer");
5549       return 1;
5550     }
5551   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5552     {
5553       error_init ("field name not in record or union initializer");
5554       return 1;
5555     }
5556
5557   constructor_designated = 1;
5558   push_init_level (2);
5559   return 0;
5560 }
5561
5562 /* If there are range designators in designator list, push a new designator
5563    to constructor_range_stack.  RANGE_END is end of such stack range or
5564    NULL_TREE if there is no range designator at this level.  */
5565
5566 static void
5567 push_range_stack (tree range_end)
5568 {
5569   struct constructor_range_stack *p;
5570
5571   p = GGC_NEW (struct constructor_range_stack);
5572   p->prev = constructor_range_stack;
5573   p->next = 0;
5574   p->fields = constructor_fields;
5575   p->range_start = constructor_index;
5576   p->index = constructor_index;
5577   p->stack = constructor_stack;
5578   p->range_end = range_end;
5579   if (constructor_range_stack)
5580     constructor_range_stack->next = p;
5581   constructor_range_stack = p;
5582 }
5583
5584 /* Within an array initializer, specify the next index to be initialized.
5585    FIRST is that index.  If LAST is nonzero, then initialize a range
5586    of indices, running from FIRST through LAST.  */
5587
5588 void
5589 set_init_index (tree first, tree last)
5590 {
5591   if (set_designator (1))
5592     return;
5593
5594   designator_erroneous = 1;
5595
5596   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5597       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5598     {
5599       error_init ("array index in initializer not of integer type");
5600       return;
5601     }
5602
5603   if (TREE_CODE (first) != INTEGER_CST)
5604     error_init ("nonconstant array index in initializer");
5605   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5606     error_init ("nonconstant array index in initializer");
5607   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5608     error_init ("array index in non-array initializer");
5609   else if (tree_int_cst_sgn (first) == -1)
5610     error_init ("array index in initializer exceeds array bounds");
5611   else if (constructor_max_index
5612            && tree_int_cst_lt (constructor_max_index, first))
5613     error_init ("array index in initializer exceeds array bounds");
5614   else
5615     {
5616       constructor_index = convert (bitsizetype, first);
5617
5618       if (last)
5619         {
5620           if (tree_int_cst_equal (first, last))
5621             last = 0;
5622           else if (tree_int_cst_lt (last, first))
5623             {
5624               error_init ("empty index range in initializer");
5625               last = 0;
5626             }
5627           else
5628             {
5629               last = convert (bitsizetype, last);
5630               if (constructor_max_index != 0
5631                   && tree_int_cst_lt (constructor_max_index, last))
5632                 {
5633                   error_init ("array index range in initializer exceeds array bounds");
5634                   last = 0;
5635                 }
5636             }
5637         }
5638
5639       designator_depth++;
5640       designator_erroneous = 0;
5641       if (constructor_range_stack || last)
5642         push_range_stack (last);
5643     }
5644 }
5645
5646 /* Within a struct initializer, specify the next field to be initialized.  */
5647
5648 void
5649 set_init_label (tree fieldname)
5650 {
5651   tree tail;
5652
5653   if (set_designator (0))
5654     return;
5655
5656   designator_erroneous = 1;
5657
5658   if (TREE_CODE (constructor_type) != RECORD_TYPE
5659       && TREE_CODE (constructor_type) != UNION_TYPE)
5660     {
5661       error_init ("field name not in record or union initializer");
5662       return;
5663     }
5664
5665   for (tail = TYPE_FIELDS (constructor_type); tail;
5666        tail = TREE_CHAIN (tail))
5667     {
5668       if (DECL_NAME (tail) == fieldname)
5669         break;
5670     }
5671
5672   if (tail == 0)
5673     error ("unknown field %qE specified in initializer", fieldname);
5674   else
5675     {
5676       constructor_fields = tail;
5677       designator_depth++;
5678       designator_erroneous = 0;
5679       if (constructor_range_stack)
5680         push_range_stack (NULL_TREE);
5681     }
5682 }
5683 \f
5684 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5685    identifies the initializer, either array index or field in a structure.
5686    VALUE is the value of that index or field.  */
5687
5688 static void
5689 add_pending_init (tree purpose, tree value)
5690 {
5691   struct init_node *p, **q, *r;
5692
5693   q = &constructor_pending_elts;
5694   p = 0;
5695
5696   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5697     {
5698       while (*q != 0)
5699         {
5700           p = *q;
5701           if (tree_int_cst_lt (purpose, p->purpose))
5702             q = &p->left;
5703           else if (tree_int_cst_lt (p->purpose, purpose))
5704             q = &p->right;
5705           else
5706             {
5707               if (TREE_SIDE_EFFECTS (p->value))
5708                 warning_init ("initialized field with side-effects overwritten");
5709               else if (warn_override_init)
5710                 warning_init ("initialized field overwritten");
5711               p->value = value;
5712               return;
5713             }
5714         }
5715     }
5716   else
5717     {
5718       tree bitpos;
5719
5720       bitpos = bit_position (purpose);
5721       while (*q != NULL)
5722         {
5723           p = *q;
5724           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5725             q = &p->left;
5726           else if (p->purpose != purpose)
5727             q = &p->right;
5728           else
5729             {
5730               if (TREE_SIDE_EFFECTS (p->value))
5731                 warning_init ("initialized field with side-effects overwritten");
5732               else if (warn_override_init)
5733                 warning_init ("initialized field overwritten");
5734               p->value = value;
5735               return;
5736             }
5737         }
5738     }
5739
5740   r = GGC_NEW (struct init_node);
5741   r->purpose = purpose;
5742   r->value = value;
5743
5744   *q = r;
5745   r->parent = p;
5746   r->left = 0;
5747   r->right = 0;
5748   r->balance = 0;
5749
5750   while (p)
5751     {
5752       struct init_node *s;
5753
5754       if (r == p->left)
5755         {
5756           if (p->balance == 0)
5757             p->balance = -1;
5758           else if (p->balance < 0)
5759             {
5760               if (r->balance < 0)
5761                 {
5762                   /* L rotation.  */
5763                   p->left = r->right;
5764                   if (p->left)
5765                     p->left->parent = p;
5766                   r->right = p;
5767
5768                   p->balance = 0;
5769                   r->balance = 0;
5770
5771                   s = p->parent;
5772                   p->parent = r;
5773                   r->parent = s;
5774                   if (s)
5775                     {
5776                       if (s->left == p)
5777                         s->left = r;
5778                       else
5779                         s->right = r;
5780                     }
5781                   else
5782                     constructor_pending_elts = r;
5783                 }
5784               else
5785                 {
5786                   /* LR rotation.  */
5787                   struct init_node *t = r->right;
5788
5789                   r->right = t->left;
5790                   if (r->right)
5791                     r->right->parent = r;
5792                   t->left = r;
5793
5794                   p->left = t->right;
5795                   if (p->left)
5796                     p->left->parent = p;
5797                   t->right = p;
5798
5799                   p->balance = t->balance < 0;
5800                   r->balance = -(t->balance > 0);
5801                   t->balance = 0;
5802
5803                   s = p->parent;
5804                   p->parent = t;
5805                   r->parent = t;
5806                   t->parent = s;
5807                   if (s)
5808                     {
5809                       if (s->left == p)
5810                         s->left = t;
5811                       else
5812                         s->right = t;
5813                     }
5814                   else
5815                     constructor_pending_elts = t;
5816                 }
5817               break;
5818             }
5819           else
5820             {
5821               /* p->balance == +1; growth of left side balances the node.  */
5822               p->balance = 0;
5823               break;
5824             }
5825         }
5826       else /* r == p->right */
5827         {
5828           if (p->balance == 0)
5829             /* Growth propagation from right side.  */
5830             p->balance++;
5831           else if (p->balance > 0)
5832             {
5833               if (r->balance > 0)
5834                 {
5835                   /* R rotation.  */
5836                   p->right = r->left;
5837                   if (p->right)
5838                     p->right->parent = p;
5839                   r->left = p;
5840
5841                   p->balance = 0;
5842                   r->balance = 0;
5843
5844                   s = p->parent;
5845                   p->parent = r;
5846                   r->parent = s;
5847                   if (s)
5848                     {
5849                       if (s->left == p)
5850                         s->left = r;
5851                       else
5852                         s->right = r;
5853                     }
5854                   else
5855                     constructor_pending_elts = r;
5856                 }
5857               else /* r->balance == -1 */
5858                 {
5859                   /* RL rotation */
5860                   struct init_node *t = r->left;
5861
5862                   r->left = t->right;
5863                   if (r->left)
5864                     r->left->parent = r;
5865                   t->right = r;
5866
5867                   p->right = t->left;
5868                   if (p->right)
5869                     p->right->parent = p;
5870                   t->left = p;
5871
5872                   r->balance = (t->balance < 0);
5873                   p->balance = -(t->balance > 0);
5874                   t->balance = 0;
5875
5876                   s = p->parent;
5877                   p->parent = t;
5878                   r->parent = t;
5879                   t->parent = s;
5880                   if (s)
5881                     {
5882                       if (s->left == p)
5883                         s->left = t;
5884                       else
5885                         s->right = t;
5886                     }
5887                   else
5888                     constructor_pending_elts = t;
5889                 }
5890               break;
5891             }
5892           else
5893             {
5894               /* p->balance == -1; growth of right side balances the node.  */
5895               p->balance = 0;
5896               break;
5897             }
5898         }
5899
5900       r = p;
5901       p = p->parent;
5902     }
5903 }
5904
5905 /* Build AVL tree from a sorted chain.  */
5906
5907 static void
5908 set_nonincremental_init (void)
5909 {
5910   unsigned HOST_WIDE_INT ix;
5911   tree index, value;
5912
5913   if (TREE_CODE (constructor_type) != RECORD_TYPE
5914       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5915     return;
5916
5917   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5918     add_pending_init (index, value);
5919   constructor_elements = 0;
5920   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5921     {
5922       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5923       /* Skip any nameless bit fields at the beginning.  */
5924       while (constructor_unfilled_fields != 0
5925              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5926              && DECL_NAME (constructor_unfilled_fields) == 0)
5927         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5928
5929     }
5930   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5931     {
5932       if (TYPE_DOMAIN (constructor_type))
5933         constructor_unfilled_index
5934             = convert (bitsizetype,
5935                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5936       else
5937         constructor_unfilled_index = bitsize_zero_node;
5938     }
5939   constructor_incremental = 0;
5940 }
5941
5942 /* Build AVL tree from a string constant.  */
5943
5944 static void
5945 set_nonincremental_init_from_string (tree str)
5946 {
5947   tree value, purpose, type;
5948   HOST_WIDE_INT val[2];
5949   const char *p, *end;
5950   int byte, wchar_bytes, charwidth, bitpos;
5951
5952   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5953
5954   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5955       == TYPE_PRECISION (char_type_node))
5956     wchar_bytes = 1;
5957   else
5958     {
5959       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5960                   == TYPE_PRECISION (wchar_type_node));
5961       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5962     }
5963   charwidth = TYPE_PRECISION (char_type_node);
5964   type = TREE_TYPE (constructor_type);
5965   p = TREE_STRING_POINTER (str);
5966   end = p + TREE_STRING_LENGTH (str);
5967
5968   for (purpose = bitsize_zero_node;
5969        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5970        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5971     {
5972       if (wchar_bytes == 1)
5973         {
5974           val[1] = (unsigned char) *p++;
5975           val[0] = 0;
5976         }
5977       else
5978         {
5979           val[0] = 0;
5980           val[1] = 0;
5981           for (byte = 0; byte < wchar_bytes; byte++)
5982             {
5983               if (BYTES_BIG_ENDIAN)
5984                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5985               else
5986                 bitpos = byte * charwidth;
5987               val[bitpos < HOST_BITS_PER_WIDE_INT]
5988                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5989                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5990             }
5991         }
5992
5993       if (!TYPE_UNSIGNED (type))
5994         {
5995           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5996           if (bitpos < HOST_BITS_PER_WIDE_INT)
5997             {
5998               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5999                 {
6000                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6001                   val[0] = -1;
6002                 }
6003             }
6004           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6005             {
6006               if (val[1] < 0)
6007                 val[0] = -1;
6008             }
6009           else if (val[0] & (((HOST_WIDE_INT) 1)
6010                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6011             val[0] |= ((HOST_WIDE_INT) -1)
6012                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6013         }
6014
6015       value = build_int_cst_wide (type, val[1], val[0]);
6016       add_pending_init (purpose, value);
6017     }
6018
6019   constructor_incremental = 0;
6020 }
6021
6022 /* Return value of FIELD in pending initializer or zero if the field was
6023    not initialized yet.  */
6024
6025 static tree
6026 find_init_member (tree field)
6027 {
6028   struct init_node *p;
6029
6030   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6031     {
6032       if (constructor_incremental
6033           && tree_int_cst_lt (field, constructor_unfilled_index))
6034         set_nonincremental_init ();
6035
6036       p = constructor_pending_elts;
6037       while (p)
6038         {
6039           if (tree_int_cst_lt (field, p->purpose))
6040             p = p->left;
6041           else if (tree_int_cst_lt (p->purpose, field))
6042             p = p->right;
6043           else
6044             return p->value;
6045         }
6046     }
6047   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6048     {
6049       tree bitpos = bit_position (field);
6050
6051       if (constructor_incremental
6052           && (!constructor_unfilled_fields
6053               || tree_int_cst_lt (bitpos,
6054                                   bit_position (constructor_unfilled_fields))))
6055         set_nonincremental_init ();
6056
6057       p = constructor_pending_elts;
6058       while (p)
6059         {
6060           if (field == p->purpose)
6061             return p->value;
6062           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6063             p = p->left;
6064           else
6065             p = p->right;
6066         }
6067     }
6068   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6069     {
6070       if (!VEC_empty (constructor_elt, constructor_elements)
6071           && (VEC_last (constructor_elt, constructor_elements)->index
6072               == field))
6073         return VEC_last (constructor_elt, constructor_elements)->value;
6074     }
6075   return 0;
6076 }
6077
6078 /* "Output" the next constructor element.
6079    At top level, really output it to assembler code now.
6080    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6081    TYPE is the data type that the containing data type wants here.
6082    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6083    If VALUE is a string constant, STRICT_STRING is true if it is
6084    unparenthesized or we should not warn here for it being parenthesized.
6085    For other types of VALUE, STRICT_STRING is not used.
6086
6087    PENDING if non-nil means output pending elements that belong
6088    right after this element.  (PENDING is normally 1;
6089    it is 0 while outputting pending elements, to avoid recursion.)  */
6090
6091 static void
6092 output_init_element (tree value, bool strict_string, tree type, tree field,
6093                      int pending)
6094 {
6095   constructor_elt *celt;
6096
6097   if (type == error_mark_node || value == error_mark_node)
6098     {
6099       constructor_erroneous = 1;
6100       return;
6101     }
6102   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6103       && (TREE_CODE (value) == STRING_CST
6104           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6105       && !(TREE_CODE (value) == STRING_CST
6106            && TREE_CODE (type) == ARRAY_TYPE
6107            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6108       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6109                      TYPE_MAIN_VARIANT (type)))
6110     value = array_to_pointer_conversion (value);
6111
6112   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6113       && require_constant_value && !flag_isoc99 && pending)
6114     {
6115       /* As an extension, allow initializing objects with static storage
6116          duration with compound literals (which are then treated just as
6117          the brace enclosed list they contain).  */
6118       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6119       value = DECL_INITIAL (decl);
6120     }
6121
6122   if (value == error_mark_node)
6123     constructor_erroneous = 1;
6124   else if (!TREE_CONSTANT (value))
6125     constructor_constant = 0;
6126   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6127            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6128                 || TREE_CODE (constructor_type) == UNION_TYPE)
6129                && DECL_C_BIT_FIELD (field)
6130                && TREE_CODE (value) != INTEGER_CST))
6131     constructor_simple = 0;
6132
6133   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6134     {
6135       if (require_constant_value)
6136         {
6137           error_init ("initializer element is not constant");
6138           value = error_mark_node;
6139         }
6140       else if (require_constant_elements)
6141         pedwarn ("initializer element is not computable at load time");
6142     }
6143
6144   /* If this field is empty (and not at the end of structure),
6145      don't do anything other than checking the initializer.  */
6146   if (field
6147       && (TREE_TYPE (field) == error_mark_node
6148           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6149               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6150               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6151                   || TREE_CHAIN (field)))))
6152     return;
6153
6154   value = digest_init (type, value, strict_string, require_constant_value);
6155   if (value == error_mark_node)
6156     {
6157       constructor_erroneous = 1;
6158       return;
6159     }
6160
6161   /* If this element doesn't come next in sequence,
6162      put it on constructor_pending_elts.  */
6163   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6164       && (!constructor_incremental
6165           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6166     {
6167       if (constructor_incremental
6168           && tree_int_cst_lt (field, constructor_unfilled_index))
6169         set_nonincremental_init ();
6170
6171       add_pending_init (field, value);
6172       return;
6173     }
6174   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6175            && (!constructor_incremental
6176                || field != constructor_unfilled_fields))
6177     {
6178       /* We do this for records but not for unions.  In a union,
6179          no matter which field is specified, it can be initialized
6180          right away since it starts at the beginning of the union.  */
6181       if (constructor_incremental)
6182         {
6183           if (!constructor_unfilled_fields)
6184             set_nonincremental_init ();
6185           else
6186             {
6187               tree bitpos, unfillpos;
6188
6189               bitpos = bit_position (field);
6190               unfillpos = bit_position (constructor_unfilled_fields);
6191
6192               if (tree_int_cst_lt (bitpos, unfillpos))
6193                 set_nonincremental_init ();
6194             }
6195         }
6196
6197       add_pending_init (field, value);
6198       return;
6199     }
6200   else if (TREE_CODE (constructor_type) == UNION_TYPE
6201            && !VEC_empty (constructor_elt, constructor_elements))
6202     {
6203       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6204                                        constructor_elements)->value))
6205         warning_init ("initialized field with side-effects overwritten");
6206       else if (warn_override_init)
6207         warning_init ("initialized field overwritten");
6208
6209       /* We can have just one union field set.  */
6210       constructor_elements = 0;
6211     }
6212
6213   /* Otherwise, output this element either to
6214      constructor_elements or to the assembler file.  */
6215
6216   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6217   celt->index = field;
6218   celt->value = value;
6219
6220   /* Advance the variable that indicates sequential elements output.  */
6221   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6222     constructor_unfilled_index
6223       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6224                     bitsize_one_node);
6225   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6226     {
6227       constructor_unfilled_fields
6228         = TREE_CHAIN (constructor_unfilled_fields);
6229
6230       /* Skip any nameless bit fields.  */
6231       while (constructor_unfilled_fields != 0
6232              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6233              && DECL_NAME (constructor_unfilled_fields) == 0)
6234         constructor_unfilled_fields =
6235           TREE_CHAIN (constructor_unfilled_fields);
6236     }
6237   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6238     constructor_unfilled_fields = 0;
6239
6240   /* Now output any pending elements which have become next.  */
6241   if (pending)
6242     output_pending_init_elements (0);
6243 }
6244
6245 /* Output any pending elements which have become next.
6246    As we output elements, constructor_unfilled_{fields,index}
6247    advances, which may cause other elements to become next;
6248    if so, they too are output.
6249
6250    If ALL is 0, we return when there are
6251    no more pending elements to output now.
6252
6253    If ALL is 1, we output space as necessary so that
6254    we can output all the pending elements.  */
6255
6256 static void
6257 output_pending_init_elements (int all)
6258 {
6259   struct init_node *elt = constructor_pending_elts;
6260   tree next;
6261
6262  retry:
6263
6264   /* Look through the whole pending tree.
6265      If we find an element that should be output now,
6266      output it.  Otherwise, set NEXT to the element
6267      that comes first among those still pending.  */
6268
6269   next = 0;
6270   while (elt)
6271     {
6272       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6273         {
6274           if (tree_int_cst_equal (elt->purpose,
6275                                   constructor_unfilled_index))
6276             output_init_element (elt->value, true,
6277                                  TREE_TYPE (constructor_type),
6278                                  constructor_unfilled_index, 0);
6279           else if (tree_int_cst_lt (constructor_unfilled_index,
6280                                     elt->purpose))
6281             {
6282               /* Advance to the next smaller node.  */
6283               if (elt->left)
6284                 elt = elt->left;
6285               else
6286                 {
6287                   /* We have reached the smallest node bigger than the
6288                      current unfilled index.  Fill the space first.  */
6289                   next = elt->purpose;
6290                   break;
6291                 }
6292             }
6293           else
6294             {
6295               /* Advance to the next bigger node.  */
6296               if (elt->right)
6297                 elt = elt->right;
6298               else
6299                 {
6300                   /* We have reached the biggest node in a subtree.  Find
6301                      the parent of it, which is the next bigger node.  */
6302                   while (elt->parent && elt->parent->right == elt)
6303                     elt = elt->parent;
6304                   elt = elt->parent;
6305                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6306                                               elt->purpose))
6307                     {
6308                       next = elt->purpose;
6309                       break;
6310                     }
6311                 }
6312             }
6313         }
6314       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6315                || TREE_CODE (constructor_type) == UNION_TYPE)
6316         {
6317           tree ctor_unfilled_bitpos, elt_bitpos;
6318
6319           /* If the current record is complete we are done.  */
6320           if (constructor_unfilled_fields == 0)
6321             break;
6322
6323           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6324           elt_bitpos = bit_position (elt->purpose);
6325           /* We can't compare fields here because there might be empty
6326              fields in between.  */
6327           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6328             {
6329               constructor_unfilled_fields = elt->purpose;
6330               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6331                                    elt->purpose, 0);
6332             }
6333           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6334             {
6335               /* Advance to the next smaller node.  */
6336               if (elt->left)
6337                 elt = elt->left;
6338               else
6339                 {
6340                   /* We have reached the smallest node bigger than the
6341                      current unfilled field.  Fill the space first.  */
6342                   next = elt->purpose;
6343                   break;
6344                 }
6345             }
6346           else
6347             {
6348               /* Advance to the next bigger node.  */
6349               if (elt->right)
6350                 elt = elt->right;
6351               else
6352                 {
6353                   /* We have reached the biggest node in a subtree.  Find
6354                      the parent of it, which is the next bigger node.  */
6355                   while (elt->parent && elt->parent->right == elt)
6356                     elt = elt->parent;
6357                   elt = elt->parent;
6358                   if (elt
6359                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6360                                            bit_position (elt->purpose))))
6361                     {
6362                       next = elt->purpose;
6363                       break;
6364                     }
6365                 }
6366             }
6367         }
6368     }
6369
6370   /* Ordinarily return, but not if we want to output all
6371      and there are elements left.  */
6372   if (!(all && next != 0))
6373     return;
6374
6375   /* If it's not incremental, just skip over the gap, so that after
6376      jumping to retry we will output the next successive element.  */
6377   if (TREE_CODE (constructor_type) == RECORD_TYPE
6378       || TREE_CODE (constructor_type) == UNION_TYPE)
6379     constructor_unfilled_fields = next;
6380   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6381     constructor_unfilled_index = next;
6382
6383   /* ELT now points to the node in the pending tree with the next
6384      initializer to output.  */
6385   goto retry;
6386 }
6387 \f
6388 /* Add one non-braced element to the current constructor level.
6389    This adjusts the current position within the constructor's type.
6390    This may also start or terminate implicit levels
6391    to handle a partly-braced initializer.
6392
6393    Once this has found the correct level for the new element,
6394    it calls output_init_element.  */
6395
6396 void
6397 process_init_element (struct c_expr value)
6398 {
6399   tree orig_value = value.value;
6400   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6401   bool strict_string = value.original_code == STRING_CST;
6402
6403   designator_depth = 0;
6404   designator_erroneous = 0;
6405
6406   /* Handle superfluous braces around string cst as in
6407      char x[] = {"foo"}; */
6408   if (string_flag
6409       && constructor_type
6410       && TREE_CODE (constructor_type) == ARRAY_TYPE
6411       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6412       && integer_zerop (constructor_unfilled_index))
6413     {
6414       if (constructor_stack->replacement_value.value)
6415         error_init ("excess elements in char array initializer");
6416       constructor_stack->replacement_value = value;
6417       return;
6418     }
6419
6420   if (constructor_stack->replacement_value.value != 0)
6421     {
6422       error_init ("excess elements in struct initializer");
6423       return;
6424     }
6425
6426   /* Ignore elements of a brace group if it is entirely superfluous
6427      and has already been diagnosed.  */
6428   if (constructor_type == 0)
6429     return;
6430
6431   /* If we've exhausted any levels that didn't have braces,
6432      pop them now.  */
6433   while (constructor_stack->implicit)
6434     {
6435       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6436            || TREE_CODE (constructor_type) == UNION_TYPE)
6437           && constructor_fields == 0)
6438         process_init_element (pop_init_level (1));
6439       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6440                && (constructor_max_index == 0
6441                    || tree_int_cst_lt (constructor_max_index,
6442                                        constructor_index)))
6443         process_init_element (pop_init_level (1));
6444       else
6445         break;
6446     }
6447
6448   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6449   if (constructor_range_stack)
6450     {
6451       /* If value is a compound literal and we'll be just using its
6452          content, don't put it into a SAVE_EXPR.  */
6453       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6454           || !require_constant_value
6455           || flag_isoc99)
6456         value.value = save_expr (value.value);
6457     }
6458
6459   while (1)
6460     {
6461       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6462         {
6463           tree fieldtype;
6464           enum tree_code fieldcode;
6465
6466           if (constructor_fields == 0)
6467             {
6468               pedwarn_init ("excess elements in struct initializer");
6469               break;
6470             }
6471
6472           fieldtype = TREE_TYPE (constructor_fields);
6473           if (fieldtype != error_mark_node)
6474             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6475           fieldcode = TREE_CODE (fieldtype);
6476
6477           /* Error for non-static initialization of a flexible array member.  */
6478           if (fieldcode == ARRAY_TYPE
6479               && !require_constant_value
6480               && TYPE_SIZE (fieldtype) == NULL_TREE
6481               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6482             {
6483               error_init ("non-static initialization of a flexible array member");
6484               break;
6485             }
6486
6487           /* Accept a string constant to initialize a subarray.  */
6488           if (value.value != 0
6489               && fieldcode == ARRAY_TYPE
6490               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6491               && string_flag)
6492             value.value = orig_value;
6493           /* Otherwise, if we have come to a subaggregate,
6494              and we don't have an element of its type, push into it.  */
6495           else if (value.value != 0
6496                    && value.value != error_mark_node
6497                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6498                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6499                        || fieldcode == UNION_TYPE))
6500             {
6501               push_init_level (1);
6502               continue;
6503             }
6504
6505           if (value.value)
6506             {
6507               push_member_name (constructor_fields);
6508               output_init_element (value.value, strict_string,
6509                                    fieldtype, constructor_fields, 1);
6510               RESTORE_SPELLING_DEPTH (constructor_depth);
6511             }
6512           else
6513             /* Do the bookkeeping for an element that was
6514                directly output as a constructor.  */
6515             {
6516               /* For a record, keep track of end position of last field.  */
6517               if (DECL_SIZE (constructor_fields))
6518                 constructor_bit_index
6519                   = size_binop (PLUS_EXPR,
6520                                 bit_position (constructor_fields),
6521                                 DECL_SIZE (constructor_fields));
6522
6523               /* If the current field was the first one not yet written out,
6524                  it isn't now, so update.  */
6525               if (constructor_unfilled_fields == constructor_fields)
6526                 {
6527                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6528                   /* Skip any nameless bit fields.  */
6529                   while (constructor_unfilled_fields != 0
6530                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6531                          && DECL_NAME (constructor_unfilled_fields) == 0)
6532                     constructor_unfilled_fields =
6533                       TREE_CHAIN (constructor_unfilled_fields);
6534                 }
6535             }
6536
6537           constructor_fields = TREE_CHAIN (constructor_fields);
6538           /* Skip any nameless bit fields at the beginning.  */
6539           while (constructor_fields != 0
6540                  && DECL_C_BIT_FIELD (constructor_fields)
6541                  && DECL_NAME (constructor_fields) == 0)
6542             constructor_fields = TREE_CHAIN (constructor_fields);
6543         }
6544       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6545         {
6546           tree fieldtype;
6547           enum tree_code fieldcode;
6548
6549           if (constructor_fields == 0)
6550             {
6551               pedwarn_init ("excess elements in union initializer");
6552               break;
6553             }
6554
6555           fieldtype = TREE_TYPE (constructor_fields);
6556           if (fieldtype != error_mark_node)
6557             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6558           fieldcode = TREE_CODE (fieldtype);
6559
6560           /* Warn that traditional C rejects initialization of unions.
6561              We skip the warning if the value is zero.  This is done
6562              under the assumption that the zero initializer in user
6563              code appears conditioned on e.g. __STDC__ to avoid
6564              "missing initializer" warnings and relies on default
6565              initialization to zero in the traditional C case.
6566              We also skip the warning if the initializer is designated,
6567              again on the assumption that this must be conditional on
6568              __STDC__ anyway (and we've already complained about the
6569              member-designator already).  */
6570           if (!in_system_header && !constructor_designated
6571               && !(value.value && (integer_zerop (value.value)
6572                                    || real_zerop (value.value))))
6573             warning (OPT_Wtraditional, "traditional C rejects initialization "
6574                      "of unions");
6575
6576           /* Accept a string constant to initialize a subarray.  */
6577           if (value.value != 0
6578               && fieldcode == ARRAY_TYPE
6579               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6580               && string_flag)
6581             value.value = orig_value;
6582           /* Otherwise, if we have come to a subaggregate,
6583              and we don't have an element of its type, push into it.  */
6584           else if (value.value != 0
6585                    && value.value != error_mark_node
6586                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6587                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6588                        || fieldcode == UNION_TYPE))
6589             {
6590               push_init_level (1);
6591               continue;
6592             }
6593
6594           if (value.value)
6595             {
6596               push_member_name (constructor_fields);
6597               output_init_element (value.value, strict_string,
6598                                    fieldtype, constructor_fields, 1);
6599               RESTORE_SPELLING_DEPTH (constructor_depth);
6600             }
6601           else
6602             /* Do the bookkeeping for an element that was
6603                directly output as a constructor.  */
6604             {
6605               constructor_bit_index = DECL_SIZE (constructor_fields);
6606               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6607             }
6608
6609           constructor_fields = 0;
6610         }
6611       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6612         {
6613           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6614           enum tree_code eltcode = TREE_CODE (elttype);
6615
6616           /* Accept a string constant to initialize a subarray.  */
6617           if (value.value != 0
6618               && eltcode == ARRAY_TYPE
6619               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6620               && string_flag)
6621             value.value = orig_value;
6622           /* Otherwise, if we have come to a subaggregate,
6623              and we don't have an element of its type, push into it.  */
6624           else if (value.value != 0
6625                    && value.value != error_mark_node
6626                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6627                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6628                        || eltcode == UNION_TYPE))
6629             {
6630               push_init_level (1);
6631               continue;
6632             }
6633
6634           if (constructor_max_index != 0
6635               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6636                   || integer_all_onesp (constructor_max_index)))
6637             {
6638               pedwarn_init ("excess elements in array initializer");
6639               break;
6640             }
6641
6642           /* Now output the actual element.  */
6643           if (value.value)
6644             {
6645               push_array_bounds (tree_low_cst (constructor_index, 1));
6646               output_init_element (value.value, strict_string,
6647                                    elttype, constructor_index, 1);
6648               RESTORE_SPELLING_DEPTH (constructor_depth);
6649             }
6650
6651           constructor_index
6652             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6653
6654           if (!value.value)
6655             /* If we are doing the bookkeeping for an element that was
6656                directly output as a constructor, we must update
6657                constructor_unfilled_index.  */
6658             constructor_unfilled_index = constructor_index;
6659         }
6660       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6661         {
6662           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6663
6664          /* Do a basic check of initializer size.  Note that vectors
6665             always have a fixed size derived from their type.  */
6666           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6667             {
6668               pedwarn_init ("excess elements in vector initializer");
6669               break;
6670             }
6671
6672           /* Now output the actual element.  */
6673           if (value.value)
6674             output_init_element (value.value, strict_string,
6675                                  elttype, constructor_index, 1);
6676
6677           constructor_index
6678             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6679
6680           if (!value.value)
6681             /* If we are doing the bookkeeping for an element that was
6682                directly output as a constructor, we must update
6683                constructor_unfilled_index.  */
6684             constructor_unfilled_index = constructor_index;
6685         }
6686
6687       /* Handle the sole element allowed in a braced initializer
6688          for a scalar variable.  */
6689       else if (constructor_type != error_mark_node
6690                && constructor_fields == 0)
6691         {
6692           pedwarn_init ("excess elements in scalar initializer");
6693           break;
6694         }
6695       else
6696         {
6697           if (value.value)
6698             output_init_element (value.value, strict_string,
6699                                  constructor_type, NULL_TREE, 1);
6700           constructor_fields = 0;
6701         }
6702
6703       /* Handle range initializers either at this level or anywhere higher
6704          in the designator stack.  */
6705       if (constructor_range_stack)
6706         {
6707           struct constructor_range_stack *p, *range_stack;
6708           int finish = 0;
6709
6710           range_stack = constructor_range_stack;
6711           constructor_range_stack = 0;
6712           while (constructor_stack != range_stack->stack)
6713             {
6714               gcc_assert (constructor_stack->implicit);
6715               process_init_element (pop_init_level (1));
6716             }
6717           for (p = range_stack;
6718                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6719                p = p->prev)
6720             {
6721               gcc_assert (constructor_stack->implicit);
6722               process_init_element (pop_init_level (1));
6723             }
6724
6725           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6726           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6727             finish = 1;
6728
6729           while (1)
6730             {
6731               constructor_index = p->index;
6732               constructor_fields = p->fields;
6733               if (finish && p->range_end && p->index == p->range_start)
6734                 {
6735                   finish = 0;
6736                   p->prev = 0;
6737                 }
6738               p = p->next;
6739               if (!p)
6740                 break;
6741               push_init_level (2);
6742               p->stack = constructor_stack;
6743               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6744                 p->index = p->range_start;
6745             }
6746
6747           if (!finish)
6748             constructor_range_stack = range_stack;
6749           continue;
6750         }
6751
6752       break;
6753     }
6754
6755   constructor_range_stack = 0;
6756 }
6757 \f
6758 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6759    (guaranteed to be 'volatile' or null) and ARGS (represented using
6760    an ASM_EXPR node).  */
6761 tree
6762 build_asm_stmt (tree cv_qualifier, tree args)
6763 {
6764   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6765     ASM_VOLATILE_P (args) = 1;
6766   return add_stmt (args);
6767 }
6768
6769 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6770    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6771    SIMPLE indicates whether there was anything at all after the
6772    string in the asm expression -- asm("blah") and asm("blah" : )
6773    are subtly different.  We use a ASM_EXPR node to represent this.  */
6774 tree
6775 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6776                 bool simple)
6777 {
6778   tree tail;
6779   tree args;
6780   int i;
6781   const char *constraint;
6782   const char **oconstraints;
6783   bool allows_mem, allows_reg, is_inout;
6784   int ninputs, noutputs;
6785
6786   ninputs = list_length (inputs);
6787   noutputs = list_length (outputs);
6788   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6789
6790   string = resolve_asm_operand_names (string, outputs, inputs);
6791
6792   /* Remove output conversions that change the type but not the mode.  */
6793   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6794     {
6795       tree output = TREE_VALUE (tail);
6796
6797       /* ??? Really, this should not be here.  Users should be using a
6798          proper lvalue, dammit.  But there's a long history of using casts
6799          in the output operands.  In cases like longlong.h, this becomes a
6800          primitive form of typechecking -- if the cast can be removed, then
6801          the output operand had a type of the proper width; otherwise we'll
6802          get an error.  Gross, but ...  */
6803       STRIP_NOPS (output);
6804
6805       if (!lvalue_or_else (output, lv_asm))
6806         output = error_mark_node;
6807
6808       if (output != error_mark_node
6809           && (TREE_READONLY (output)
6810               || TYPE_READONLY (TREE_TYPE (output))
6811               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6812                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6813                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6814         readonly_error (output, lv_asm);
6815
6816       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6817       oconstraints[i] = constraint;
6818
6819       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6820                                    &allows_mem, &allows_reg, &is_inout))
6821         {
6822           /* If the operand is going to end up in memory,
6823              mark it addressable.  */
6824           if (!allows_reg && !c_mark_addressable (output))
6825             output = error_mark_node;
6826         }
6827       else
6828         output = error_mark_node;
6829
6830       TREE_VALUE (tail) = output;
6831     }
6832
6833   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6834     {
6835       tree input;
6836
6837       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6838       input = TREE_VALUE (tail);
6839
6840       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6841                                   oconstraints, &allows_mem, &allows_reg))
6842         {
6843           /* If the operand is going to end up in memory,
6844              mark it addressable.  */
6845           if (!allows_reg && allows_mem)
6846             {
6847               /* Strip the nops as we allow this case.  FIXME, this really
6848                  should be rejected or made deprecated.  */
6849               STRIP_NOPS (input);
6850               if (!c_mark_addressable (input))
6851                 input = error_mark_node;
6852           }
6853         }
6854       else
6855         input = error_mark_node;
6856
6857       TREE_VALUE (tail) = input;
6858     }
6859
6860   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6861
6862   /* asm statements without outputs, including simple ones, are treated
6863      as volatile.  */
6864   ASM_INPUT_P (args) = simple;
6865   ASM_VOLATILE_P (args) = (noutputs == 0);
6866
6867   return args;
6868 }
6869 \f
6870 /* Generate a goto statement to LABEL.  */
6871
6872 tree
6873 c_finish_goto_label (tree label)
6874 {
6875   tree decl = lookup_label (label);
6876   if (!decl)
6877     return NULL_TREE;
6878
6879   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6880     {
6881       error ("jump into statement expression");
6882       return NULL_TREE;
6883     }
6884
6885   if (C_DECL_UNJUMPABLE_VM (decl))
6886     {
6887       error ("jump into scope of identifier with variably modified type");
6888       return NULL_TREE;
6889     }
6890
6891   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6892     {
6893       /* No jump from outside this statement expression context, so
6894          record that there is a jump from within this context.  */
6895       struct c_label_list *nlist;
6896       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6897       nlist->next = label_context_stack_se->labels_used;
6898       nlist->label = decl;
6899       label_context_stack_se->labels_used = nlist;
6900     }
6901
6902   if (!C_DECL_UNDEFINABLE_VM (decl))
6903     {
6904       /* No jump from outside this context context of identifiers with
6905          variably modified type, so record that there is a jump from
6906          within this context.  */
6907       struct c_label_list *nlist;
6908       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6909       nlist->next = label_context_stack_vm->labels_used;
6910       nlist->label = decl;
6911       label_context_stack_vm->labels_used = nlist;
6912     }
6913
6914   TREE_USED (decl) = 1;
6915   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6916 }
6917
6918 /* Generate a computed goto statement to EXPR.  */
6919
6920 tree
6921 c_finish_goto_ptr (tree expr)
6922 {
6923   if (pedantic)
6924     pedwarn ("ISO C forbids %<goto *expr;%>");
6925   expr = convert (ptr_type_node, expr);
6926   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6927 }
6928
6929 /* Generate a C `return' statement.  RETVAL is the expression for what
6930    to return, or a null pointer for `return;' with no value.  */
6931
6932 tree
6933 c_finish_return (tree retval)
6934 {
6935   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6936   bool no_warning = false;
6937
6938   if (TREE_THIS_VOLATILE (current_function_decl))
6939     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6940
6941   if (!retval)
6942     {
6943       current_function_returns_null = 1;
6944       if ((warn_return_type || flag_isoc99)
6945           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6946         {
6947           pedwarn_c99 ("%<return%> with no value, in "
6948                        "function returning non-void");
6949           no_warning = true;
6950         }
6951     }
6952   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6953     {
6954       current_function_returns_null = 1;
6955       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6956         pedwarn ("%<return%> with a value, in function returning void");
6957       else if (pedantic)
6958         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
6959     }
6960   else
6961     {
6962       tree t = convert_for_assignment (valtype, retval, ic_return,
6963                                        NULL_TREE, NULL_TREE, 0);
6964       tree res = DECL_RESULT (current_function_decl);
6965       tree inner;
6966
6967       current_function_returns_value = 1;
6968       if (t == error_mark_node)
6969         return NULL_TREE;
6970
6971       inner = t = convert (TREE_TYPE (res), t);
6972
6973       /* Strip any conversions, additions, and subtractions, and see if
6974          we are returning the address of a local variable.  Warn if so.  */
6975       while (1)
6976         {
6977           switch (TREE_CODE (inner))
6978             {
6979             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6980             case PLUS_EXPR:
6981               inner = TREE_OPERAND (inner, 0);
6982               continue;
6983
6984             case MINUS_EXPR:
6985               /* If the second operand of the MINUS_EXPR has a pointer
6986                  type (or is converted from it), this may be valid, so
6987                  don't give a warning.  */
6988               {
6989                 tree op1 = TREE_OPERAND (inner, 1);
6990
6991                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6992                        && (TREE_CODE (op1) == NOP_EXPR
6993                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6994                            || TREE_CODE (op1) == CONVERT_EXPR))
6995                   op1 = TREE_OPERAND (op1, 0);
6996
6997                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6998                   break;
6999
7000                 inner = TREE_OPERAND (inner, 0);
7001                 continue;
7002               }
7003
7004             case ADDR_EXPR:
7005               inner = TREE_OPERAND (inner, 0);
7006
7007               while (REFERENCE_CLASS_P (inner)
7008                      && TREE_CODE (inner) != INDIRECT_REF)
7009                 inner = TREE_OPERAND (inner, 0);
7010
7011               if (DECL_P (inner)
7012                   && !DECL_EXTERNAL (inner)
7013                   && !TREE_STATIC (inner)
7014                   && DECL_CONTEXT (inner) == current_function_decl)
7015                 warning (0, "function returns address of local variable");
7016               break;
7017
7018             default:
7019               break;
7020             }
7021
7022           break;
7023         }
7024
7025       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7026     }
7027
7028   ret_stmt = build_stmt (RETURN_EXPR, retval);
7029   TREE_NO_WARNING (ret_stmt) |= no_warning;
7030   return add_stmt (ret_stmt);
7031 }
7032 \f
7033 struct c_switch {
7034   /* The SWITCH_EXPR being built.  */
7035   tree switch_expr;
7036
7037   /* The original type of the testing expression, i.e. before the
7038      default conversion is applied.  */
7039   tree orig_type;
7040
7041   /* A splay-tree mapping the low element of a case range to the high
7042      element, or NULL_TREE if there is no high element.  Used to
7043      determine whether or not a new case label duplicates an old case
7044      label.  We need a tree, rather than simply a hash table, because
7045      of the GNU case range extension.  */
7046   splay_tree cases;
7047
7048   /* Number of nested statement expressions within this switch
7049      statement; if nonzero, case and default labels may not
7050      appear.  */
7051   unsigned int blocked_stmt_expr;
7052
7053   /* Scope of outermost declarations of identifiers with variably
7054      modified type within this switch statement; if nonzero, case and
7055      default labels may not appear.  */
7056   unsigned int blocked_vm;
7057
7058   /* The next node on the stack.  */
7059   struct c_switch *next;
7060 };
7061
7062 /* A stack of the currently active switch statements.  The innermost
7063    switch statement is on the top of the stack.  There is no need to
7064    mark the stack for garbage collection because it is only active
7065    during the processing of the body of a function, and we never
7066    collect at that point.  */
7067
7068 struct c_switch *c_switch_stack;
7069
7070 /* Start a C switch statement, testing expression EXP.  Return the new
7071    SWITCH_EXPR.  */
7072
7073 tree
7074 c_start_case (tree exp)
7075 {
7076   tree orig_type = error_mark_node;
7077   struct c_switch *cs;
7078
7079   if (exp != error_mark_node)
7080     {
7081       orig_type = TREE_TYPE (exp);
7082
7083       if (!INTEGRAL_TYPE_P (orig_type))
7084         {
7085           if (orig_type != error_mark_node)
7086             {
7087               error ("switch quantity not an integer");
7088               orig_type = error_mark_node;
7089             }
7090           exp = integer_zero_node;
7091         }
7092       else
7093         {
7094           tree type = TYPE_MAIN_VARIANT (orig_type);
7095
7096           if (!in_system_header
7097               && (type == long_integer_type_node
7098                   || type == long_unsigned_type_node))
7099             warning (OPT_Wtraditional, "%<long%> switch expression not "
7100                      "converted to %<int%> in ISO C");
7101
7102           exp = default_conversion (exp);
7103         }
7104     }
7105
7106   /* Add this new SWITCH_EXPR to the stack.  */
7107   cs = XNEW (struct c_switch);
7108   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7109   cs->orig_type = orig_type;
7110   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7111   cs->blocked_stmt_expr = 0;
7112   cs->blocked_vm = 0;
7113   cs->next = c_switch_stack;
7114   c_switch_stack = cs;
7115
7116   return add_stmt (cs->switch_expr);
7117 }
7118
7119 /* Process a case label.  */
7120
7121 tree
7122 do_case (tree low_value, tree high_value)
7123 {
7124   tree label = NULL_TREE;
7125
7126   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7127       && !c_switch_stack->blocked_vm)
7128     {
7129       label = c_add_case_label (c_switch_stack->cases,
7130                                 SWITCH_COND (c_switch_stack->switch_expr),
7131                                 c_switch_stack->orig_type,
7132                                 low_value, high_value);
7133       if (label == error_mark_node)
7134         label = NULL_TREE;
7135     }
7136   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7137     {
7138       if (low_value)
7139         error ("case label in statement expression not containing "
7140                "enclosing switch statement");
7141       else
7142         error ("%<default%> label in statement expression not containing "
7143                "enclosing switch statement");
7144     }
7145   else if (c_switch_stack && c_switch_stack->blocked_vm)
7146     {
7147       if (low_value)
7148         error ("case label in scope of identifier with variably modified "
7149                "type not containing enclosing switch statement");
7150       else
7151         error ("%<default%> label in scope of identifier with variably "
7152                "modified type not containing enclosing switch statement");
7153     }
7154   else if (low_value)
7155     error ("case label not within a switch statement");
7156   else
7157     error ("%<default%> label not within a switch statement");
7158
7159   return label;
7160 }
7161
7162 /* Finish the switch statement.  */
7163
7164 void
7165 c_finish_case (tree body)
7166 {
7167   struct c_switch *cs = c_switch_stack;
7168   location_t switch_location;
7169
7170   SWITCH_BODY (cs->switch_expr) = body;
7171
7172   /* We must not be within a statement expression nested in the switch
7173      at this point; we might, however, be within the scope of an
7174      identifier with variably modified type nested in the switch.  */
7175   gcc_assert (!cs->blocked_stmt_expr);
7176
7177   /* Emit warnings as needed.  */
7178   if (EXPR_HAS_LOCATION (cs->switch_expr))
7179     switch_location = EXPR_LOCATION (cs->switch_expr);
7180   else
7181     switch_location = input_location;
7182   c_do_switch_warnings (cs->cases, switch_location,
7183                         TREE_TYPE (cs->switch_expr),
7184                         SWITCH_COND (cs->switch_expr));
7185
7186   /* Pop the stack.  */
7187   c_switch_stack = cs->next;
7188   splay_tree_delete (cs->cases);
7189   XDELETE (cs);
7190 }
7191 \f
7192 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7193    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7194    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7195    statement, and was not surrounded with parenthesis.  */
7196
7197 void
7198 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7199                   tree else_block, bool nested_if)
7200 {
7201   tree stmt;
7202
7203   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7204   if (warn_parentheses && nested_if && else_block == NULL)
7205     {
7206       tree inner_if = then_block;
7207
7208       /* We know from the grammar productions that there is an IF nested
7209          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7210          it might not be exactly THEN_BLOCK, but should be the last
7211          non-container statement within.  */
7212       while (1)
7213         switch (TREE_CODE (inner_if))
7214           {
7215           case COND_EXPR:
7216             goto found;
7217           case BIND_EXPR:
7218             inner_if = BIND_EXPR_BODY (inner_if);
7219             break;
7220           case STATEMENT_LIST:
7221             inner_if = expr_last (then_block);
7222             break;
7223           case TRY_FINALLY_EXPR:
7224           case TRY_CATCH_EXPR:
7225             inner_if = TREE_OPERAND (inner_if, 0);
7226             break;
7227           default:
7228             gcc_unreachable ();
7229           }
7230     found:
7231
7232       if (COND_EXPR_ELSE (inner_if))
7233          warning (OPT_Wparentheses,
7234                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7235                   &if_locus);
7236     }
7237
7238   empty_if_body_warning (then_block, else_block);
7239
7240   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7241   SET_EXPR_LOCATION (stmt, if_locus);
7242   add_stmt (stmt);
7243 }
7244
7245 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7246    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7247    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7248    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7249    the continue label.  Everything is allowed to be NULL.  */
7250
7251 void
7252 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7253                tree blab, tree clab, bool cond_is_first)
7254 {
7255   tree entry = NULL, exit = NULL, t;
7256
7257   /* If the condition is zero don't generate a loop construct.  */
7258   if (cond && integer_zerop (cond))
7259     {
7260       if (cond_is_first)
7261         {
7262           t = build_and_jump (&blab);
7263           SET_EXPR_LOCATION (t, start_locus);
7264           add_stmt (t);
7265         }
7266     }
7267   else
7268     {
7269       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7270
7271       /* If we have an exit condition, then we build an IF with gotos either
7272          out of the loop, or to the top of it.  If there's no exit condition,
7273          then we just build a jump back to the top.  */
7274       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7275
7276       if (cond && !integer_nonzerop (cond))
7277         {
7278           /* Canonicalize the loop condition to the end.  This means
7279              generating a branch to the loop condition.  Reuse the
7280              continue label, if possible.  */
7281           if (cond_is_first)
7282             {
7283               if (incr || !clab)
7284                 {
7285                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7286                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7287                 }
7288               else
7289                 t = build1 (GOTO_EXPR, void_type_node, clab);
7290               SET_EXPR_LOCATION (t, start_locus);
7291               add_stmt (t);
7292             }
7293
7294           t = build_and_jump (&blab);
7295           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7296           if (cond_is_first)
7297             SET_EXPR_LOCATION (exit, start_locus);
7298           else
7299             SET_EXPR_LOCATION (exit, input_location);
7300         }
7301
7302       add_stmt (top);
7303     }
7304
7305   if (body)
7306     add_stmt (body);
7307   if (clab)
7308     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7309   if (incr)
7310     add_stmt (incr);
7311   if (entry)
7312     add_stmt (entry);
7313   if (exit)
7314     add_stmt (exit);
7315   if (blab)
7316     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7317 }
7318
7319 tree
7320 c_finish_bc_stmt (tree *label_p, bool is_break)
7321 {
7322   bool skip;
7323   tree label = *label_p;
7324
7325   /* In switch statements break is sometimes stylistically used after
7326      a return statement.  This can lead to spurious warnings about
7327      control reaching the end of a non-void function when it is
7328      inlined.  Note that we are calling block_may_fallthru with
7329      language specific tree nodes; this works because
7330      block_may_fallthru returns true when given something it does not
7331      understand.  */
7332   skip = !block_may_fallthru (cur_stmt_list);
7333
7334   if (!label)
7335     {
7336       if (!skip)
7337         *label_p = label = create_artificial_label ();
7338     }
7339   else if (TREE_CODE (label) == LABEL_DECL)
7340     ;
7341   else switch (TREE_INT_CST_LOW (label))
7342     {
7343     case 0:
7344       if (is_break)
7345         error ("break statement not within loop or switch");
7346       else
7347         error ("continue statement not within a loop");
7348       return NULL_TREE;
7349
7350     case 1:
7351       gcc_assert (is_break);
7352       error ("break statement used with OpenMP for loop");
7353       return NULL_TREE;
7354
7355     default:
7356       gcc_unreachable ();
7357     }
7358
7359   if (skip)
7360     return NULL_TREE;
7361
7362   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7363 }
7364
7365 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7366
7367 static void
7368 emit_side_effect_warnings (tree expr)
7369 {
7370   if (expr == error_mark_node)
7371     ;
7372   else if (!TREE_SIDE_EFFECTS (expr))
7373     {
7374       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7375         warning (OPT_Wunused_value, "%Hstatement with no effect",
7376                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7377     }
7378   else
7379     warn_if_unused_value (expr, input_location);
7380 }
7381
7382 /* Process an expression as if it were a complete statement.  Emit
7383    diagnostics, but do not call ADD_STMT.  */
7384
7385 tree
7386 c_process_expr_stmt (tree expr)
7387 {
7388   if (!expr)
7389     return NULL_TREE;
7390
7391   if (warn_sequence_point)
7392     verify_sequence_points (expr);
7393
7394   if (TREE_TYPE (expr) != error_mark_node
7395       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7396       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7397     error ("expression statement has incomplete type");
7398
7399   /* If we're not processing a statement expression, warn about unused values.
7400      Warnings for statement expressions will be emitted later, once we figure
7401      out which is the result.  */
7402   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7403       && warn_unused_value)
7404     emit_side_effect_warnings (expr);
7405
7406   /* If the expression is not of a type to which we cannot assign a line
7407      number, wrap the thing in a no-op NOP_EXPR.  */
7408   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7409     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7410
7411   if (CAN_HAVE_LOCATION_P (expr))
7412     SET_EXPR_LOCATION (expr, input_location);
7413
7414   return expr;
7415 }
7416
7417 /* Emit an expression as a statement.  */
7418
7419 tree
7420 c_finish_expr_stmt (tree expr)
7421 {
7422   if (expr)
7423     return add_stmt (c_process_expr_stmt (expr));
7424   else
7425     return NULL;
7426 }
7427
7428 /* Do the opposite and emit a statement as an expression.  To begin,
7429    create a new binding level and return it.  */
7430
7431 tree
7432 c_begin_stmt_expr (void)
7433 {
7434   tree ret;
7435   struct c_label_context_se *nstack;
7436   struct c_label_list *glist;
7437
7438   /* We must force a BLOCK for this level so that, if it is not expanded
7439      later, there is a way to turn off the entire subtree of blocks that
7440      are contained in it.  */
7441   keep_next_level ();
7442   ret = c_begin_compound_stmt (true);
7443   if (c_switch_stack)
7444     {
7445       c_switch_stack->blocked_stmt_expr++;
7446       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7447     }
7448   for (glist = label_context_stack_se->labels_used;
7449        glist != NULL;
7450        glist = glist->next)
7451     {
7452       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7453     }
7454   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7455   nstack->labels_def = NULL;
7456   nstack->labels_used = NULL;
7457   nstack->next = label_context_stack_se;
7458   label_context_stack_se = nstack;
7459
7460   /* Mark the current statement list as belonging to a statement list.  */
7461   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7462
7463   return ret;
7464 }
7465
7466 tree
7467 c_finish_stmt_expr (tree body)
7468 {
7469   tree last, type, tmp, val;
7470   tree *last_p;
7471   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7472
7473   body = c_end_compound_stmt (body, true);
7474   if (c_switch_stack)
7475     {
7476       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7477       c_switch_stack->blocked_stmt_expr--;
7478     }
7479   /* It is no longer possible to jump to labels defined within this
7480      statement expression.  */
7481   for (dlist = label_context_stack_se->labels_def;
7482        dlist != NULL;
7483        dlist = dlist->next)
7484     {
7485       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7486     }
7487   /* It is again possible to define labels with a goto just outside
7488      this statement expression.  */
7489   for (glist = label_context_stack_se->next->labels_used;
7490        glist != NULL;
7491        glist = glist->next)
7492     {
7493       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7494       glist_prev = glist;
7495     }
7496   if (glist_prev != NULL)
7497     glist_prev->next = label_context_stack_se->labels_used;
7498   else
7499     label_context_stack_se->next->labels_used
7500       = label_context_stack_se->labels_used;
7501   label_context_stack_se = label_context_stack_se->next;
7502
7503   /* Locate the last statement in BODY.  See c_end_compound_stmt
7504      about always returning a BIND_EXPR.  */
7505   last_p = &BIND_EXPR_BODY (body);
7506   last = BIND_EXPR_BODY (body);
7507
7508  continue_searching:
7509   if (TREE_CODE (last) == STATEMENT_LIST)
7510     {
7511       tree_stmt_iterator i;
7512
7513       /* This can happen with degenerate cases like ({ }).  No value.  */
7514       if (!TREE_SIDE_EFFECTS (last))
7515         return body;
7516
7517       /* If we're supposed to generate side effects warnings, process
7518          all of the statements except the last.  */
7519       if (warn_unused_value)
7520         {
7521           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7522             emit_side_effect_warnings (tsi_stmt (i));
7523         }
7524       else
7525         i = tsi_last (last);
7526       last_p = tsi_stmt_ptr (i);
7527       last = *last_p;
7528     }
7529
7530   /* If the end of the list is exception related, then the list was split
7531      by a call to push_cleanup.  Continue searching.  */
7532   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7533       || TREE_CODE (last) == TRY_CATCH_EXPR)
7534     {
7535       last_p = &TREE_OPERAND (last, 0);
7536       last = *last_p;
7537       goto continue_searching;
7538     }
7539
7540   /* In the case that the BIND_EXPR is not necessary, return the
7541      expression out from inside it.  */
7542   if (last == error_mark_node
7543       || (last == BIND_EXPR_BODY (body)
7544           && BIND_EXPR_VARS (body) == NULL))
7545     {
7546       /* Do not warn if the return value of a statement expression is
7547          unused.  */
7548       if (CAN_HAVE_LOCATION_P (last))
7549         TREE_NO_WARNING (last) = 1;
7550       return last;
7551     }
7552
7553   /* Extract the type of said expression.  */
7554   type = TREE_TYPE (last);
7555
7556   /* If we're not returning a value at all, then the BIND_EXPR that
7557      we already have is a fine expression to return.  */
7558   if (!type || VOID_TYPE_P (type))
7559     return body;
7560
7561   /* Now that we've located the expression containing the value, it seems
7562      silly to make voidify_wrapper_expr repeat the process.  Create a
7563      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7564   tmp = create_tmp_var_raw (type, NULL);
7565
7566   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7567      tree_expr_nonnegative_p giving up immediately.  */
7568   val = last;
7569   if (TREE_CODE (val) == NOP_EXPR
7570       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7571     val = TREE_OPERAND (val, 0);
7572
7573   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7574   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7575
7576   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7577 }
7578
7579 /* Begin the scope of an identifier of variably modified type, scope
7580    number SCOPE.  Jumping from outside this scope to inside it is not
7581    permitted.  */
7582
7583 void
7584 c_begin_vm_scope (unsigned int scope)
7585 {
7586   struct c_label_context_vm *nstack;
7587   struct c_label_list *glist;
7588
7589   gcc_assert (scope > 0);
7590
7591   /* At file_scope, we don't have to do any processing.  */
7592   if (label_context_stack_vm == NULL)
7593     return;
7594
7595   if (c_switch_stack && !c_switch_stack->blocked_vm)
7596     c_switch_stack->blocked_vm = scope;
7597   for (glist = label_context_stack_vm->labels_used;
7598        glist != NULL;
7599        glist = glist->next)
7600     {
7601       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7602     }
7603   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7604   nstack->labels_def = NULL;
7605   nstack->labels_used = NULL;
7606   nstack->scope = scope;
7607   nstack->next = label_context_stack_vm;
7608   label_context_stack_vm = nstack;
7609 }
7610
7611 /* End a scope which may contain identifiers of variably modified
7612    type, scope number SCOPE.  */
7613
7614 void
7615 c_end_vm_scope (unsigned int scope)
7616 {
7617   if (label_context_stack_vm == NULL)
7618     return;
7619   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7620     c_switch_stack->blocked_vm = 0;
7621   /* We may have a number of nested scopes of identifiers with
7622      variably modified type, all at this depth.  Pop each in turn.  */
7623   while (label_context_stack_vm->scope == scope)
7624     {
7625       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7626
7627       /* It is no longer possible to jump to labels defined within this
7628          scope.  */
7629       for (dlist = label_context_stack_vm->labels_def;
7630            dlist != NULL;
7631            dlist = dlist->next)
7632         {
7633           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7634         }
7635       /* It is again possible to define labels with a goto just outside
7636          this scope.  */
7637       for (glist = label_context_stack_vm->next->labels_used;
7638            glist != NULL;
7639            glist = glist->next)
7640         {
7641           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7642           glist_prev = glist;
7643         }
7644       if (glist_prev != NULL)
7645         glist_prev->next = label_context_stack_vm->labels_used;
7646       else
7647         label_context_stack_vm->next->labels_used
7648           = label_context_stack_vm->labels_used;
7649       label_context_stack_vm = label_context_stack_vm->next;
7650     }
7651 }
7652 \f
7653 /* Begin and end compound statements.  This is as simple as pushing
7654    and popping new statement lists from the tree.  */
7655
7656 tree
7657 c_begin_compound_stmt (bool do_scope)
7658 {
7659   tree stmt = push_stmt_list ();
7660   if (do_scope)
7661     push_scope ();
7662   return stmt;
7663 }
7664
7665 tree
7666 c_end_compound_stmt (tree stmt, bool do_scope)
7667 {
7668   tree block = NULL;
7669
7670   if (do_scope)
7671     {
7672       if (c_dialect_objc ())
7673         objc_clear_super_receiver ();
7674       block = pop_scope ();
7675     }
7676
7677   stmt = pop_stmt_list (stmt);
7678   stmt = c_build_bind_expr (block, stmt);
7679
7680   /* If this compound statement is nested immediately inside a statement
7681      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7682      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7683      STATEMENT_LISTs merge, and thus we can lose track of what statement
7684      was really last.  */
7685   if (cur_stmt_list
7686       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7687       && TREE_CODE (stmt) != BIND_EXPR)
7688     {
7689       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7690       TREE_SIDE_EFFECTS (stmt) = 1;
7691     }
7692
7693   return stmt;
7694 }
7695
7696 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7697    when the current scope is exited.  EH_ONLY is true when this is not
7698    meant to apply to normal control flow transfer.  */
7699
7700 void
7701 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7702 {
7703   enum tree_code code;
7704   tree stmt, list;
7705   bool stmt_expr;
7706
7707   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7708   stmt = build_stmt (code, NULL, cleanup);
7709   add_stmt (stmt);
7710   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7711   list = push_stmt_list ();
7712   TREE_OPERAND (stmt, 0) = list;
7713   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7714 }
7715 \f
7716 /* Build a binary-operation expression without default conversions.
7717    CODE is the kind of expression to build.
7718    This function differs from `build' in several ways:
7719    the data type of the result is computed and recorded in it,
7720    warnings are generated if arg data types are invalid,
7721    special handling for addition and subtraction of pointers is known,
7722    and some optimization is done (operations on narrow ints
7723    are done in the narrower type when that gives the same result).
7724    Constant folding is also done before the result is returned.
7725
7726    Note that the operands will never have enumeral types, or function
7727    or array types, because either they will have the default conversions
7728    performed or they have both just been converted to some other type in which
7729    the arithmetic is to be done.  */
7730
7731 tree
7732 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7733                  int convert_p)
7734 {
7735   tree type0, type1;
7736   enum tree_code code0, code1;
7737   tree op0, op1;
7738   const char *invalid_op_diag;
7739
7740   /* Expression code to give to the expression when it is built.
7741      Normally this is CODE, which is what the caller asked for,
7742      but in some special cases we change it.  */
7743   enum tree_code resultcode = code;
7744
7745   /* Data type in which the computation is to be performed.
7746      In the simplest cases this is the common type of the arguments.  */
7747   tree result_type = NULL;
7748
7749   /* Nonzero means operands have already been type-converted
7750      in whatever way is necessary.
7751      Zero means they need to be converted to RESULT_TYPE.  */
7752   int converted = 0;
7753
7754   /* Nonzero means create the expression with this type, rather than
7755      RESULT_TYPE.  */
7756   tree build_type = 0;
7757
7758   /* Nonzero means after finally constructing the expression
7759      convert it to this type.  */
7760   tree final_type = 0;
7761
7762   /* Nonzero if this is an operation like MIN or MAX which can
7763      safely be computed in short if both args are promoted shorts.
7764      Also implies COMMON.
7765      -1 indicates a bitwise operation; this makes a difference
7766      in the exact conditions for when it is safe to do the operation
7767      in a narrower mode.  */
7768   int shorten = 0;
7769
7770   /* Nonzero if this is a comparison operation;
7771      if both args are promoted shorts, compare the original shorts.
7772      Also implies COMMON.  */
7773   int short_compare = 0;
7774
7775   /* Nonzero if this is a right-shift operation, which can be computed on the
7776      original short and then promoted if the operand is a promoted short.  */
7777   int short_shift = 0;
7778
7779   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7780   int common = 0;
7781
7782   /* True means types are compatible as far as ObjC is concerned.  */
7783   bool objc_ok;
7784
7785   if (convert_p)
7786     {
7787       op0 = default_conversion (orig_op0);
7788       op1 = default_conversion (orig_op1);
7789     }
7790   else
7791     {
7792       op0 = orig_op0;
7793       op1 = orig_op1;
7794     }
7795
7796   type0 = TREE_TYPE (op0);
7797   type1 = TREE_TYPE (op1);
7798
7799   /* The expression codes of the data types of the arguments tell us
7800      whether the arguments are integers, floating, pointers, etc.  */
7801   code0 = TREE_CODE (type0);
7802   code1 = TREE_CODE (type1);
7803
7804   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7805   STRIP_TYPE_NOPS (op0);
7806   STRIP_TYPE_NOPS (op1);
7807
7808   /* If an error was already reported for one of the arguments,
7809      avoid reporting another error.  */
7810
7811   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7812     return error_mark_node;
7813
7814   if ((invalid_op_diag
7815        = targetm.invalid_binary_op (code, type0, type1)))
7816     {
7817       error (invalid_op_diag);
7818       return error_mark_node;
7819     }
7820
7821   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7822
7823   switch (code)
7824     {
7825     case PLUS_EXPR:
7826       /* Handle the pointer + int case.  */
7827       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7828         return pointer_int_sum (PLUS_EXPR, op0, op1);
7829       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7830         return pointer_int_sum (PLUS_EXPR, op1, op0);
7831       else
7832         common = 1;
7833       break;
7834
7835     case MINUS_EXPR:
7836       /* Subtraction of two similar pointers.
7837          We must subtract them as integers, then divide by object size.  */
7838       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7839           && comp_target_types (type0, type1))
7840         return pointer_diff (op0, op1);
7841       /* Handle pointer minus int.  Just like pointer plus int.  */
7842       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7843         return pointer_int_sum (MINUS_EXPR, op0, op1);
7844       else
7845         common = 1;
7846       break;
7847
7848     case MULT_EXPR:
7849       common = 1;
7850       break;
7851
7852     case TRUNC_DIV_EXPR:
7853     case CEIL_DIV_EXPR:
7854     case FLOOR_DIV_EXPR:
7855     case ROUND_DIV_EXPR:
7856     case EXACT_DIV_EXPR:
7857       warn_for_div_by_zero (op1);
7858
7859       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7860            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7861           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7862               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7863         {
7864           enum tree_code tcode0 = code0, tcode1 = code1;
7865
7866           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7867             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7868           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7869             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7870
7871           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7872             resultcode = RDIV_EXPR;
7873           else
7874             /* Although it would be tempting to shorten always here, that
7875                loses on some targets, since the modulo instruction is
7876                undefined if the quotient can't be represented in the
7877                computation mode.  We shorten only if unsigned or if
7878                dividing by something we know != -1.  */
7879             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7880                        || (TREE_CODE (op1) == INTEGER_CST
7881                            && !integer_all_onesp (op1)));
7882           common = 1;
7883         }
7884       break;
7885
7886     case BIT_AND_EXPR:
7887     case BIT_IOR_EXPR:
7888     case BIT_XOR_EXPR:
7889       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7890         shorten = -1;
7891       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7892         common = 1;
7893       break;
7894
7895     case TRUNC_MOD_EXPR:
7896     case FLOOR_MOD_EXPR:
7897       warn_for_div_by_zero (op1);
7898
7899       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7900         {
7901           /* Although it would be tempting to shorten always here, that loses
7902              on some targets, since the modulo instruction is undefined if the
7903              quotient can't be represented in the computation mode.  We shorten
7904              only if unsigned or if dividing by something we know != -1.  */
7905           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7906                      || (TREE_CODE (op1) == INTEGER_CST
7907                          && !integer_all_onesp (op1)));
7908           common = 1;
7909         }
7910       break;
7911
7912     case TRUTH_ANDIF_EXPR:
7913     case TRUTH_ORIF_EXPR:
7914     case TRUTH_AND_EXPR:
7915     case TRUTH_OR_EXPR:
7916     case TRUTH_XOR_EXPR:
7917       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7918            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7919           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7920               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7921         {
7922           /* Result of these operations is always an int,
7923              but that does not mean the operands should be
7924              converted to ints!  */
7925           result_type = integer_type_node;
7926           op0 = c_common_truthvalue_conversion (op0);
7927           op1 = c_common_truthvalue_conversion (op1);
7928           converted = 1;
7929         }
7930       break;
7931
7932       /* Shift operations: result has same type as first operand;
7933          always convert second operand to int.
7934          Also set SHORT_SHIFT if shifting rightward.  */
7935
7936     case RSHIFT_EXPR:
7937       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7938         {
7939           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7940             {
7941               if (tree_int_cst_sgn (op1) < 0)
7942                 warning (0, "right shift count is negative");
7943               else
7944                 {
7945                   if (!integer_zerop (op1))
7946                     short_shift = 1;
7947
7948                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7949                     warning (0, "right shift count >= width of type");
7950                 }
7951             }
7952
7953           /* Use the type of the value to be shifted.  */
7954           result_type = type0;
7955           /* Convert the shift-count to an integer, regardless of size
7956              of value being shifted.  */
7957           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7958             op1 = convert (integer_type_node, op1);
7959           /* Avoid converting op1 to result_type later.  */
7960           converted = 1;
7961         }
7962       break;
7963
7964     case LSHIFT_EXPR:
7965       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7966         {
7967           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7968             {
7969               if (tree_int_cst_sgn (op1) < 0)
7970                 warning (0, "left shift count is negative");
7971
7972               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7973                 warning (0, "left shift count >= width of type");
7974             }
7975
7976           /* Use the type of the value to be shifted.  */
7977           result_type = type0;
7978           /* Convert the shift-count to an integer, regardless of size
7979              of value being shifted.  */
7980           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7981             op1 = convert (integer_type_node, op1);
7982           /* Avoid converting op1 to result_type later.  */
7983           converted = 1;
7984         }
7985       break;
7986
7987     case EQ_EXPR:
7988     case NE_EXPR:
7989       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7990         warning (OPT_Wfloat_equal,
7991                  "comparing floating point with == or != is unsafe");
7992       /* Result of comparison is always int,
7993          but don't convert the args to int!  */
7994       build_type = integer_type_node;
7995       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7996            || code0 == COMPLEX_TYPE)
7997           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7998               || code1 == COMPLEX_TYPE))
7999         short_compare = 1;
8000       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8001         {
8002           tree tt0 = TREE_TYPE (type0);
8003           tree tt1 = TREE_TYPE (type1);
8004           /* Anything compares with void *.  void * compares with anything.
8005              Otherwise, the targets must be compatible
8006              and both must be object or both incomplete.  */
8007           if (comp_target_types (type0, type1))
8008             result_type = common_pointer_type (type0, type1);
8009           else if (VOID_TYPE_P (tt0))
8010             {
8011               /* op0 != orig_op0 detects the case of something
8012                  whose value is 0 but which isn't a valid null ptr const.  */
8013               if (pedantic && !null_pointer_constant_p (orig_op0)
8014                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8015                 pedwarn ("ISO C forbids comparison of %<void *%>"
8016                          " with function pointer");
8017             }
8018           else if (VOID_TYPE_P (tt1))
8019             {
8020               if (pedantic && !null_pointer_constant_p (orig_op1)
8021                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8022                 pedwarn ("ISO C forbids comparison of %<void *%>"
8023                          " with function pointer");
8024             }
8025           else
8026             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8027             if (!objc_ok)
8028               pedwarn ("comparison of distinct pointer types lacks a cast");
8029
8030           if (result_type == NULL_TREE)
8031             result_type = ptr_type_node;
8032         }
8033       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8034         {
8035           if (TREE_CODE (op0) == ADDR_EXPR
8036               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8037             warning (OPT_Waddress, "the address of %qD will never be NULL",
8038                      TREE_OPERAND (op0, 0));
8039           result_type = type0;
8040         }
8041       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8042         {
8043           if (TREE_CODE (op1) == ADDR_EXPR
8044               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8045             warning (OPT_Waddress, "the address of %qD will never be NULL",
8046                      TREE_OPERAND (op1, 0));
8047           result_type = type1;
8048         }
8049       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8050         {
8051           result_type = type0;
8052           pedwarn ("comparison between pointer and integer");
8053         }
8054       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8055         {
8056           result_type = type1;
8057           pedwarn ("comparison between pointer and integer");
8058         }
8059       break;
8060
8061     case LE_EXPR:
8062     case GE_EXPR:
8063     case LT_EXPR:
8064     case GT_EXPR:
8065       build_type = integer_type_node;
8066       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
8067           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
8068         short_compare = 1;
8069       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8070         {
8071           if (comp_target_types (type0, type1))
8072             {
8073               result_type = common_pointer_type (type0, type1);
8074               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8075                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8076                 pedwarn ("comparison of complete and incomplete pointers");
8077               else if (pedantic
8078                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8079                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8080             }
8081           else
8082             {
8083               result_type = ptr_type_node;
8084               pedwarn ("comparison of distinct pointer types lacks a cast");
8085             }
8086         }
8087       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8088         {
8089           result_type = type0;
8090           if (pedantic || extra_warnings)
8091             pedwarn ("ordered comparison of pointer with integer zero");
8092         }
8093       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8094         {
8095           result_type = type1;
8096           if (pedantic)
8097             pedwarn ("ordered comparison of pointer with integer zero");
8098         }
8099       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8100         {
8101           result_type = type0;
8102           pedwarn ("comparison between pointer and integer");
8103         }
8104       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8105         {
8106           result_type = type1;
8107           pedwarn ("comparison between pointer and integer");
8108         }
8109       break;
8110
8111     default:
8112       gcc_unreachable ();
8113     }
8114
8115   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8116     return error_mark_node;
8117
8118   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8119       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8120           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8121                                                     TREE_TYPE (type1))))
8122     {
8123       binary_op_error (code);
8124       return error_mark_node;
8125     }
8126
8127   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8128        || code0 == VECTOR_TYPE)
8129       &&
8130       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8131        || code1 == VECTOR_TYPE))
8132     {
8133       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8134
8135       if (shorten || common || short_compare)
8136         result_type = c_common_type (type0, type1);
8137
8138       /* For certain operations (which identify themselves by shorten != 0)
8139          if both args were extended from the same smaller type,
8140          do the arithmetic in that type and then extend.
8141
8142          shorten !=0 and !=1 indicates a bitwise operation.
8143          For them, this optimization is safe only if
8144          both args are zero-extended or both are sign-extended.
8145          Otherwise, we might change the result.
8146          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8147          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8148
8149       if (shorten && none_complex)
8150         {
8151           int unsigned0, unsigned1;
8152           tree arg0, arg1;
8153           int uns;
8154           tree type;
8155
8156           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8157              excessive narrowing when we call get_narrower below.  For
8158              example, suppose that OP0 is of unsigned int extended
8159              from signed char and that RESULT_TYPE is long long int.
8160              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8161              like
8162
8163                (long long int) (unsigned int) signed_char
8164
8165              which get_narrower would narrow down to
8166
8167                (unsigned int) signed char
8168
8169              If we do not cast OP0 first, get_narrower would return
8170              signed_char, which is inconsistent with the case of the
8171              explicit cast.  */
8172           op0 = convert (result_type, op0);
8173           op1 = convert (result_type, op1);
8174
8175           arg0 = get_narrower (op0, &unsigned0);
8176           arg1 = get_narrower (op1, &unsigned1);
8177
8178           /* UNS is 1 if the operation to be done is an unsigned one.  */
8179           uns = TYPE_UNSIGNED (result_type);
8180
8181           final_type = result_type;
8182
8183           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8184              but it *requires* conversion to FINAL_TYPE.  */
8185
8186           if ((TYPE_PRECISION (TREE_TYPE (op0))
8187                == TYPE_PRECISION (TREE_TYPE (arg0)))
8188               && TREE_TYPE (op0) != final_type)
8189             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8190           if ((TYPE_PRECISION (TREE_TYPE (op1))
8191                == TYPE_PRECISION (TREE_TYPE (arg1)))
8192               && TREE_TYPE (op1) != final_type)
8193             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8194
8195           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8196
8197           /* For bitwise operations, signedness of nominal type
8198              does not matter.  Consider only how operands were extended.  */
8199           if (shorten == -1)
8200             uns = unsigned0;
8201
8202           /* Note that in all three cases below we refrain from optimizing
8203              an unsigned operation on sign-extended args.
8204              That would not be valid.  */
8205
8206           /* Both args variable: if both extended in same way
8207              from same width, do it in that width.
8208              Do it unsigned if args were zero-extended.  */
8209           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8210                < TYPE_PRECISION (result_type))
8211               && (TYPE_PRECISION (TREE_TYPE (arg1))
8212                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8213               && unsigned0 == unsigned1
8214               && (unsigned0 || !uns))
8215             result_type
8216               = c_common_signed_or_unsigned_type
8217               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8218           else if (TREE_CODE (arg0) == INTEGER_CST
8219                    && (unsigned1 || !uns)
8220                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8221                        < TYPE_PRECISION (result_type))
8222                    && (type
8223                        = c_common_signed_or_unsigned_type (unsigned1,
8224                                                            TREE_TYPE (arg1)),
8225                        int_fits_type_p (arg0, type)))
8226             result_type = type;
8227           else if (TREE_CODE (arg1) == INTEGER_CST
8228                    && (unsigned0 || !uns)
8229                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8230                        < TYPE_PRECISION (result_type))
8231                    && (type
8232                        = c_common_signed_or_unsigned_type (unsigned0,
8233                                                            TREE_TYPE (arg0)),
8234                        int_fits_type_p (arg1, type)))
8235             result_type = type;
8236         }
8237
8238       /* Shifts can be shortened if shifting right.  */
8239
8240       if (short_shift)
8241         {
8242           int unsigned_arg;
8243           tree arg0 = get_narrower (op0, &unsigned_arg);
8244
8245           final_type = result_type;
8246
8247           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8248             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8249
8250           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8251               /* We can shorten only if the shift count is less than the
8252                  number of bits in the smaller type size.  */
8253               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8254               /* We cannot drop an unsigned shift after sign-extension.  */
8255               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8256             {
8257               /* Do an unsigned shift if the operand was zero-extended.  */
8258               result_type
8259                 = c_common_signed_or_unsigned_type (unsigned_arg,
8260                                                     TREE_TYPE (arg0));
8261               /* Convert value-to-be-shifted to that type.  */
8262               if (TREE_TYPE (op0) != result_type)
8263                 op0 = convert (result_type, op0);
8264               converted = 1;
8265             }
8266         }
8267
8268       /* Comparison operations are shortened too but differently.
8269          They identify themselves by setting short_compare = 1.  */
8270
8271       if (short_compare)
8272         {
8273           /* Don't write &op0, etc., because that would prevent op0
8274              from being kept in a register.
8275              Instead, make copies of the our local variables and
8276              pass the copies by reference, then copy them back afterward.  */
8277           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8278           enum tree_code xresultcode = resultcode;
8279           tree val
8280             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8281
8282           if (val != 0)
8283             return val;
8284
8285           op0 = xop0, op1 = xop1;
8286           converted = 1;
8287           resultcode = xresultcode;
8288
8289           if (warn_sign_compare && skip_evaluation == 0)
8290             {
8291               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8292               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8293               int unsignedp0, unsignedp1;
8294               tree primop0 = get_narrower (op0, &unsignedp0);
8295               tree primop1 = get_narrower (op1, &unsignedp1);
8296
8297               xop0 = orig_op0;
8298               xop1 = orig_op1;
8299               STRIP_TYPE_NOPS (xop0);
8300               STRIP_TYPE_NOPS (xop1);
8301
8302               /* Give warnings for comparisons between signed and unsigned
8303                  quantities that may fail.
8304
8305                  Do the checking based on the original operand trees, so that
8306                  casts will be considered, but default promotions won't be.
8307
8308                  Do not warn if the comparison is being done in a signed type,
8309                  since the signed type will only be chosen if it can represent
8310                  all the values of the unsigned type.  */
8311               if (!TYPE_UNSIGNED (result_type))
8312                 /* OK */;
8313               /* Do not warn if both operands are the same signedness.  */
8314               else if (op0_signed == op1_signed)
8315                 /* OK */;
8316               else
8317                 {
8318                   tree sop, uop;
8319                   bool ovf;
8320
8321                   if (op0_signed)
8322                     sop = xop0, uop = xop1;
8323                   else
8324                     sop = xop1, uop = xop0;
8325
8326                   /* Do not warn if the signed quantity is an
8327                      unsuffixed integer literal (or some static
8328                      constant expression involving such literals or a
8329                      conditional expression involving such literals)
8330                      and it is non-negative.  */
8331                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8332                     /* OK */;
8333                   /* Do not warn if the comparison is an equality operation,
8334                      the unsigned quantity is an integral constant, and it
8335                      would fit in the result if the result were signed.  */
8336                   else if (TREE_CODE (uop) == INTEGER_CST
8337                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8338                            && int_fits_type_p
8339                            (uop, c_common_signed_type (result_type)))
8340                     /* OK */;
8341                   /* Do not warn if the unsigned quantity is an enumeration
8342                      constant and its maximum value would fit in the result
8343                      if the result were signed.  */
8344                   else if (TREE_CODE (uop) == INTEGER_CST
8345                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8346                            && int_fits_type_p
8347                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8348                             c_common_signed_type (result_type)))
8349                     /* OK */;
8350                   else
8351                     warning (0, "comparison between signed and unsigned");
8352                 }
8353
8354               /* Warn if two unsigned values are being compared in a size
8355                  larger than their original size, and one (and only one) is the
8356                  result of a `~' operator.  This comparison will always fail.
8357
8358                  Also warn if one operand is a constant, and the constant
8359                  does not have all bits set that are set in the ~ operand
8360                  when it is extended.  */
8361
8362               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8363                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8364                 {
8365                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8366                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8367                                             &unsignedp0);
8368                   else
8369                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8370                                             &unsignedp1);
8371
8372                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8373                     {
8374                       tree primop;
8375                       HOST_WIDE_INT constant, mask;
8376                       int unsignedp, bits;
8377
8378                       if (host_integerp (primop0, 0))
8379                         {
8380                           primop = primop1;
8381                           unsignedp = unsignedp1;
8382                           constant = tree_low_cst (primop0, 0);
8383                         }
8384                       else
8385                         {
8386                           primop = primop0;
8387                           unsignedp = unsignedp0;
8388                           constant = tree_low_cst (primop1, 0);
8389                         }
8390
8391                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8392                       if (bits < TYPE_PRECISION (result_type)
8393                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8394                         {
8395                           mask = (~(HOST_WIDE_INT) 0) << bits;
8396                           if ((mask & constant) != mask)
8397                             warning (0, "comparison of promoted ~unsigned with constant");
8398                         }
8399                     }
8400                   else if (unsignedp0 && unsignedp1
8401                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8402                                < TYPE_PRECISION (result_type))
8403                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8404                                < TYPE_PRECISION (result_type)))
8405                     warning (0, "comparison of promoted ~unsigned with unsigned");
8406                 }
8407             }
8408         }
8409     }
8410
8411   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8412      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8413      Then the expression will be built.
8414      It will be given type FINAL_TYPE if that is nonzero;
8415      otherwise, it will be given type RESULT_TYPE.  */
8416
8417   if (!result_type)
8418     {
8419       binary_op_error (code);
8420       return error_mark_node;
8421     }
8422
8423   if (!converted)
8424     {
8425       if (TREE_TYPE (op0) != result_type)
8426         op0 = convert_and_check (result_type, op0);
8427       if (TREE_TYPE (op1) != result_type)
8428         op1 = convert_and_check (result_type, op1);
8429
8430       /* This can happen if one operand has a vector type, and the other
8431          has a different type.  */
8432       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8433         return error_mark_node;
8434     }
8435
8436   if (build_type == NULL_TREE)
8437     build_type = result_type;
8438
8439   {
8440     /* Treat expressions in initializers specially as they can't trap.  */
8441     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8442                                                                     build_type,
8443                                                                     op0, op1)
8444                                          : fold_build2 (resultcode, build_type,
8445                                                         op0, op1);
8446
8447     if (final_type != 0)
8448       result = convert (final_type, result);
8449     return result;
8450   }
8451 }
8452
8453
8454 /* Convert EXPR to be a truth-value, validating its type for this
8455    purpose.  */
8456
8457 tree
8458 c_objc_common_truthvalue_conversion (tree expr)
8459 {
8460   switch (TREE_CODE (TREE_TYPE (expr)))
8461     {
8462     case ARRAY_TYPE:
8463       error ("used array that cannot be converted to pointer where scalar is required");
8464       return error_mark_node;
8465
8466     case RECORD_TYPE:
8467       error ("used struct type value where scalar is required");
8468       return error_mark_node;
8469
8470     case UNION_TYPE:
8471       error ("used union type value where scalar is required");
8472       return error_mark_node;
8473
8474     case FUNCTION_TYPE:
8475       gcc_unreachable ();
8476
8477     default:
8478       break;
8479     }
8480
8481   /* ??? Should we also give an error for void and vectors rather than
8482      leaving those to give errors later?  */
8483   return c_common_truthvalue_conversion (expr);
8484 }
8485 \f
8486
8487 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8488    required.  */
8489
8490 tree
8491 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8492                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8493 {
8494   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8495     {
8496       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8497       /* Executing a compound literal inside a function reinitializes
8498          it.  */
8499       if (!TREE_STATIC (decl))
8500         *se = true;
8501       return decl;
8502     }
8503   else
8504     return expr;
8505 }
8506 \f
8507 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8508
8509 tree
8510 c_begin_omp_parallel (void)
8511 {
8512   tree block;
8513
8514   keep_next_level ();
8515   block = c_begin_compound_stmt (true);
8516
8517   return block;
8518 }
8519
8520 tree
8521 c_finish_omp_parallel (tree clauses, tree block)
8522 {
8523   tree stmt;
8524
8525   block = c_end_compound_stmt (block, true);
8526
8527   stmt = make_node (OMP_PARALLEL);
8528   TREE_TYPE (stmt) = void_type_node;
8529   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8530   OMP_PARALLEL_BODY (stmt) = block;
8531
8532   return add_stmt (stmt);
8533 }
8534
8535 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8536    Remove any elements from the list that are invalid.  */
8537
8538 tree
8539 c_finish_omp_clauses (tree clauses)
8540 {
8541   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8542   tree c, t, *pc = &clauses;
8543   const char *name;
8544
8545   bitmap_obstack_initialize (NULL);
8546   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8547   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8548   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8549
8550   for (pc = &clauses, c = clauses; c ; c = *pc)
8551     {
8552       bool remove = false;
8553       bool need_complete = false;
8554       bool need_implicitly_determined = false;
8555
8556       switch (OMP_CLAUSE_CODE (c))
8557         {
8558         case OMP_CLAUSE_SHARED:
8559           name = "shared";
8560           need_implicitly_determined = true;
8561           goto check_dup_generic;
8562
8563         case OMP_CLAUSE_PRIVATE:
8564           name = "private";
8565           need_complete = true;
8566           need_implicitly_determined = true;
8567           goto check_dup_generic;
8568
8569         case OMP_CLAUSE_REDUCTION:
8570           name = "reduction";
8571           need_implicitly_determined = true;
8572           t = OMP_CLAUSE_DECL (c);
8573           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8574               || POINTER_TYPE_P (TREE_TYPE (t)))
8575             {
8576               error ("%qE has invalid type for %<reduction%>", t);
8577               remove = true;
8578             }
8579           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8580             {
8581               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8582               const char *r_name = NULL;
8583
8584               switch (r_code)
8585                 {
8586                 case PLUS_EXPR:
8587                 case MULT_EXPR:
8588                 case MINUS_EXPR:
8589                   break;
8590                 case BIT_AND_EXPR:
8591                   r_name = "&";
8592                   break;
8593                 case BIT_XOR_EXPR:
8594                   r_name = "^";
8595                   break;
8596                 case BIT_IOR_EXPR:
8597                   r_name = "|";
8598                   break;
8599                 case TRUTH_ANDIF_EXPR:
8600                   r_name = "&&";
8601                   break;
8602                 case TRUTH_ORIF_EXPR:
8603                   r_name = "||";
8604                   break;
8605                 default:
8606                   gcc_unreachable ();
8607                 }
8608               if (r_name)
8609                 {
8610                   error ("%qE has invalid type for %<reduction(%s)%>",
8611                          t, r_name);
8612                   remove = true;
8613                 }
8614             }
8615           goto check_dup_generic;
8616
8617         case OMP_CLAUSE_COPYPRIVATE:
8618           name = "copyprivate";
8619           goto check_dup_generic;
8620
8621         case OMP_CLAUSE_COPYIN:
8622           name = "copyin";
8623           t = OMP_CLAUSE_DECL (c);
8624           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8625             {
8626               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8627               remove = true;
8628             }
8629           goto check_dup_generic;
8630
8631         check_dup_generic:
8632           t = OMP_CLAUSE_DECL (c);
8633           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8634             {
8635               error ("%qE is not a variable in clause %qs", t, name);
8636               remove = true;
8637             }
8638           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8639                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8640                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8641             {
8642               error ("%qE appears more than once in data clauses", t);
8643               remove = true;
8644             }
8645           else
8646             bitmap_set_bit (&generic_head, DECL_UID (t));
8647           break;
8648
8649         case OMP_CLAUSE_FIRSTPRIVATE:
8650           name = "firstprivate";
8651           t = OMP_CLAUSE_DECL (c);
8652           need_complete = true;
8653           need_implicitly_determined = true;
8654           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8655             {
8656               error ("%qE is not a variable in clause %<firstprivate%>", t);
8657               remove = true;
8658             }
8659           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8660                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8661             {
8662               error ("%qE appears more than once in data clauses", t);
8663               remove = true;
8664             }
8665           else
8666             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8667           break;
8668
8669         case OMP_CLAUSE_LASTPRIVATE:
8670           name = "lastprivate";
8671           t = OMP_CLAUSE_DECL (c);
8672           need_complete = true;
8673           need_implicitly_determined = true;
8674           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8675             {
8676               error ("%qE is not a variable in clause %<lastprivate%>", t);
8677               remove = true;
8678             }
8679           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8680                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8681             {
8682               error ("%qE appears more than once in data clauses", t);
8683               remove = true;
8684             }
8685           else
8686             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8687           break;
8688
8689         case OMP_CLAUSE_IF:
8690         case OMP_CLAUSE_NUM_THREADS:
8691         case OMP_CLAUSE_SCHEDULE:
8692         case OMP_CLAUSE_NOWAIT:
8693         case OMP_CLAUSE_ORDERED:
8694         case OMP_CLAUSE_DEFAULT:
8695           pc = &OMP_CLAUSE_CHAIN (c);
8696           continue;
8697
8698         default:
8699           gcc_unreachable ();
8700         }
8701
8702       if (!remove)
8703         {
8704           t = OMP_CLAUSE_DECL (c);
8705
8706           if (need_complete)
8707             {
8708               t = require_complete_type (t);
8709               if (t == error_mark_node)
8710                 remove = true;
8711             }
8712
8713           if (need_implicitly_determined)
8714             {
8715               const char *share_name = NULL;
8716
8717               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8718                 share_name = "threadprivate";
8719               else switch (c_omp_predetermined_sharing (t))
8720                 {
8721                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8722                   break;
8723                 case OMP_CLAUSE_DEFAULT_SHARED:
8724                   share_name = "shared";
8725                   break;
8726                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8727                   share_name = "private";
8728                   break;
8729                 default:
8730                   gcc_unreachable ();
8731                 }
8732               if (share_name)
8733                 {
8734                   error ("%qE is predetermined %qs for %qs",
8735                          t, share_name, name);
8736                   remove = true;
8737                 }
8738             }
8739         }
8740
8741       if (remove)
8742         *pc = OMP_CLAUSE_CHAIN (c);
8743       else
8744         pc = &OMP_CLAUSE_CHAIN (c);
8745     }
8746
8747   bitmap_obstack_release (NULL);
8748   return clauses;
8749 }