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   /* Warn about comparisons against string literals, with the exception
2644      of testing for equality or inequality of a string literal with NULL.  */
2645   if (code == EQ_EXPR || code == NE_EXPR)
2646     {
2647       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2648           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2649         warning (OPT_Waddress, "comparison with string literal results in unspecified behaviour");
2650     }
2651   else if (TREE_CODE_CLASS (code) == tcc_comparison
2652            && (code1 == STRING_CST || code2 == STRING_CST))
2653     warning (OPT_Waddress, "comparison with string literal results in unspecified behaviour");
2654
2655   if (TREE_OVERFLOW_P (result.value)
2656       && !TREE_OVERFLOW_P (arg1.value)
2657       && !TREE_OVERFLOW_P (arg2.value))
2658     overflow_warning (result.value);
2659
2660   return result;
2661 }
2662 \f
2663 /* Return a tree for the difference of pointers OP0 and OP1.
2664    The resulting tree has type int.  */
2665
2666 static tree
2667 pointer_diff (tree op0, tree op1)
2668 {
2669   tree restype = ptrdiff_type_node;
2670
2671   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2672   tree con0, con1, lit0, lit1;
2673   tree orig_op1 = op1;
2674
2675   if (pedantic || warn_pointer_arith)
2676     {
2677       if (TREE_CODE (target_type) == VOID_TYPE)
2678         pedwarn ("pointer of type %<void *%> used in subtraction");
2679       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2680         pedwarn ("pointer to a function used in subtraction");
2681     }
2682
2683   /* If the conversion to ptrdiff_type does anything like widening or
2684      converting a partial to an integral mode, we get a convert_expression
2685      that is in the way to do any simplifications.
2686      (fold-const.c doesn't know that the extra bits won't be needed.
2687      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2688      different mode in place.)
2689      So first try to find a common term here 'by hand'; we want to cover
2690      at least the cases that occur in legal static initializers.  */
2691   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2692       && (TYPE_PRECISION (TREE_TYPE (op0))
2693           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2694     con0 = TREE_OPERAND (op0, 0);
2695   else
2696     con0 = op0;
2697   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2698       && (TYPE_PRECISION (TREE_TYPE (op1))
2699           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2700     con1 = TREE_OPERAND (op1, 0);
2701   else
2702     con1 = op1;
2703
2704   if (TREE_CODE (con0) == PLUS_EXPR)
2705     {
2706       lit0 = TREE_OPERAND (con0, 1);
2707       con0 = TREE_OPERAND (con0, 0);
2708     }
2709   else
2710     lit0 = integer_zero_node;
2711
2712   if (TREE_CODE (con1) == PLUS_EXPR)
2713     {
2714       lit1 = TREE_OPERAND (con1, 1);
2715       con1 = TREE_OPERAND (con1, 0);
2716     }
2717   else
2718     lit1 = integer_zero_node;
2719
2720   if (operand_equal_p (con0, con1, 0))
2721     {
2722       op0 = lit0;
2723       op1 = lit1;
2724     }
2725
2726
2727   /* First do the subtraction as integers;
2728      then drop through to build the divide operator.
2729      Do not do default conversions on the minus operator
2730      in case restype is a short type.  */
2731
2732   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2733                          convert (restype, op1), 0);
2734   /* This generates an error if op1 is pointer to incomplete type.  */
2735   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2736     error ("arithmetic on pointer to an incomplete type");
2737
2738   /* This generates an error if op0 is pointer to incomplete type.  */
2739   op1 = c_size_in_bytes (target_type);
2740
2741   /* Divide by the size, in easiest possible way.  */
2742   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2743 }
2744 \f
2745 /* Construct and perhaps optimize a tree representation
2746    for a unary operation.  CODE, a tree_code, specifies the operation
2747    and XARG is the operand.
2748    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2749    the default promotions (such as from short to int).
2750    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2751    allows non-lvalues; this is only used to handle conversion of non-lvalue
2752    arrays to pointers in C99.  */
2753
2754 tree
2755 build_unary_op (enum tree_code code, tree xarg, int flag)
2756 {
2757   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2758   tree arg = xarg;
2759   tree argtype = 0;
2760   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2761   tree val;
2762   int noconvert = flag;
2763   const char *invalid_op_diag;
2764
2765   if (typecode == ERROR_MARK)
2766     return error_mark_node;
2767   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2768     typecode = INTEGER_TYPE;
2769
2770   if ((invalid_op_diag
2771        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2772     {
2773       error (invalid_op_diag);
2774       return error_mark_node;
2775     }
2776
2777   switch (code)
2778     {
2779     case CONVERT_EXPR:
2780       /* This is used for unary plus, because a CONVERT_EXPR
2781          is enough to prevent anybody from looking inside for
2782          associativity, but won't generate any code.  */
2783       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2784             || typecode == COMPLEX_TYPE
2785             || typecode == VECTOR_TYPE))
2786         {
2787           error ("wrong type argument to unary plus");
2788           return error_mark_node;
2789         }
2790       else if (!noconvert)
2791         arg = default_conversion (arg);
2792       arg = non_lvalue (arg);
2793       break;
2794
2795     case NEGATE_EXPR:
2796       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2797             || typecode == COMPLEX_TYPE
2798             || typecode == VECTOR_TYPE))
2799         {
2800           error ("wrong type argument to unary minus");
2801           return error_mark_node;
2802         }
2803       else if (!noconvert)
2804         arg = default_conversion (arg);
2805       break;
2806
2807     case BIT_NOT_EXPR:
2808       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2809         {
2810           if (!noconvert)
2811             arg = default_conversion (arg);
2812         }
2813       else if (typecode == COMPLEX_TYPE)
2814         {
2815           code = CONJ_EXPR;
2816           if (pedantic)
2817             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2818           if (!noconvert)
2819             arg = default_conversion (arg);
2820         }
2821       else
2822         {
2823           error ("wrong type argument to bit-complement");
2824           return error_mark_node;
2825         }
2826       break;
2827
2828     case ABS_EXPR:
2829       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2830         {
2831           error ("wrong type argument to abs");
2832           return error_mark_node;
2833         }
2834       else if (!noconvert)
2835         arg = default_conversion (arg);
2836       break;
2837
2838     case CONJ_EXPR:
2839       /* Conjugating a real value is a no-op, but allow it anyway.  */
2840       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2841             || typecode == COMPLEX_TYPE))
2842         {
2843           error ("wrong type argument to conjugation");
2844           return error_mark_node;
2845         }
2846       else if (!noconvert)
2847         arg = default_conversion (arg);
2848       break;
2849
2850     case TRUTH_NOT_EXPR:
2851       if (typecode != INTEGER_TYPE
2852           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2853           && typecode != COMPLEX_TYPE)
2854         {
2855           error ("wrong type argument to unary exclamation mark");
2856           return error_mark_node;
2857         }
2858       arg = c_objc_common_truthvalue_conversion (arg);
2859       return invert_truthvalue (arg);
2860
2861     case REALPART_EXPR:
2862       if (TREE_CODE (arg) == COMPLEX_CST)
2863         return TREE_REALPART (arg);
2864       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2865         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2866       else
2867         return arg;
2868
2869     case IMAGPART_EXPR:
2870       if (TREE_CODE (arg) == COMPLEX_CST)
2871         return TREE_IMAGPART (arg);
2872       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2873         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2874       else
2875         return convert (TREE_TYPE (arg), integer_zero_node);
2876
2877     case PREINCREMENT_EXPR:
2878     case POSTINCREMENT_EXPR:
2879     case PREDECREMENT_EXPR:
2880     case POSTDECREMENT_EXPR:
2881
2882       /* Increment or decrement the real part of the value,
2883          and don't change the imaginary part.  */
2884       if (typecode == COMPLEX_TYPE)
2885         {
2886           tree real, imag;
2887
2888           if (pedantic)
2889             pedwarn ("ISO C does not support %<++%> and %<--%>"
2890                      " on complex types");
2891
2892           arg = stabilize_reference (arg);
2893           real = build_unary_op (REALPART_EXPR, arg, 1);
2894           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2895           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2896                          build_unary_op (code, real, 1), imag);
2897         }
2898
2899       /* Report invalid types.  */
2900
2901       if (typecode != POINTER_TYPE
2902           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2903         {
2904           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2905             error ("wrong type argument to increment");
2906           else
2907             error ("wrong type argument to decrement");
2908
2909           return error_mark_node;
2910         }
2911
2912       {
2913         tree inc;
2914         tree result_type = TREE_TYPE (arg);
2915
2916         arg = get_unwidened (arg, 0);
2917         argtype = TREE_TYPE (arg);
2918
2919         /* Compute the increment.  */
2920
2921         if (typecode == POINTER_TYPE)
2922           {
2923             /* If pointer target is an undefined struct,
2924                we just cannot know how to do the arithmetic.  */
2925             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2926               {
2927                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2928                   error ("increment of pointer to unknown structure");
2929                 else
2930                   error ("decrement of pointer to unknown structure");
2931               }
2932             else if ((pedantic || warn_pointer_arith)
2933                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2934                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2935               {
2936                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2937                   pedwarn ("wrong type argument to increment");
2938                 else
2939                   pedwarn ("wrong type argument to decrement");
2940               }
2941
2942             inc = c_size_in_bytes (TREE_TYPE (result_type));
2943           }
2944         else
2945           inc = integer_one_node;
2946
2947         inc = convert (argtype, inc);
2948
2949         /* Complain about anything else that is not a true lvalue.  */
2950         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2951                                     || code == POSTINCREMENT_EXPR)
2952                                    ? lv_increment
2953                                    : lv_decrement)))
2954           return error_mark_node;
2955
2956         /* Report a read-only lvalue.  */
2957         if (TREE_READONLY (arg))
2958           {
2959             readonly_error (arg,
2960                             ((code == PREINCREMENT_EXPR
2961                               || code == POSTINCREMENT_EXPR)
2962                              ? lv_increment : lv_decrement));
2963             return error_mark_node;
2964           }
2965
2966         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2967           val = boolean_increment (code, arg);
2968         else
2969           val = build2 (code, TREE_TYPE (arg), arg, inc);
2970         TREE_SIDE_EFFECTS (val) = 1;
2971         val = convert (result_type, val);
2972         if (TREE_CODE (val) != code)
2973           TREE_NO_WARNING (val) = 1;
2974         return val;
2975       }
2976
2977     case ADDR_EXPR:
2978       /* Note that this operation never does default_conversion.  */
2979
2980       /* Let &* cancel out to simplify resulting code.  */
2981       if (TREE_CODE (arg) == INDIRECT_REF)
2982         {
2983           /* Don't let this be an lvalue.  */
2984           if (lvalue_p (TREE_OPERAND (arg, 0)))
2985             return non_lvalue (TREE_OPERAND (arg, 0));
2986           return TREE_OPERAND (arg, 0);
2987         }
2988
2989       /* For &x[y], return x+y */
2990       if (TREE_CODE (arg) == ARRAY_REF)
2991         {
2992           tree op0 = TREE_OPERAND (arg, 0);
2993           if (!c_mark_addressable (op0))
2994             return error_mark_node;
2995           return build_binary_op (PLUS_EXPR,
2996                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2997                                    ? array_to_pointer_conversion (op0)
2998                                    : op0),
2999                                   TREE_OPERAND (arg, 1), 1);
3000         }
3001
3002       /* Anything not already handled and not a true memory reference
3003          or a non-lvalue array is an error.  */
3004       else if (typecode != FUNCTION_TYPE && !flag
3005                && !lvalue_or_else (arg, lv_addressof))
3006         return error_mark_node;
3007
3008       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3009       argtype = TREE_TYPE (arg);
3010
3011       /* If the lvalue is const or volatile, merge that into the type
3012          to which the address will point.  Note that you can't get a
3013          restricted pointer by taking the address of something, so we
3014          only have to deal with `const' and `volatile' here.  */
3015       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3016           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3017           argtype = c_build_type_variant (argtype,
3018                                           TREE_READONLY (arg),
3019                                           TREE_THIS_VOLATILE (arg));
3020
3021       if (!c_mark_addressable (arg))
3022         return error_mark_node;
3023
3024       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3025                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3026
3027       argtype = build_pointer_type (argtype);
3028
3029       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3030          when we have proper support for integer constant expressions.  */
3031       val = get_base_address (arg);
3032       if (val && TREE_CODE (val) == INDIRECT_REF
3033           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3034         {
3035           tree op0 = fold_convert (argtype, fold_offsetof (arg, val)), op1;
3036
3037           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3038           return fold_build2 (PLUS_EXPR, argtype, op0, op1);
3039         }
3040
3041       val = build1 (ADDR_EXPR, argtype, arg);
3042
3043       return val;
3044
3045     default:
3046       gcc_unreachable ();
3047     }
3048
3049   if (argtype == 0)
3050     argtype = TREE_TYPE (arg);
3051   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3052                                 : fold_build1 (code, argtype, arg);
3053 }
3054
3055 /* Return nonzero if REF is an lvalue valid for this language.
3056    Lvalues can be assigned, unless their type has TYPE_READONLY.
3057    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3058
3059 static int
3060 lvalue_p (tree ref)
3061 {
3062   enum tree_code code = TREE_CODE (ref);
3063
3064   switch (code)
3065     {
3066     case REALPART_EXPR:
3067     case IMAGPART_EXPR:
3068     case COMPONENT_REF:
3069       return lvalue_p (TREE_OPERAND (ref, 0));
3070
3071     case COMPOUND_LITERAL_EXPR:
3072     case STRING_CST:
3073       return 1;
3074
3075     case INDIRECT_REF:
3076     case ARRAY_REF:
3077     case VAR_DECL:
3078     case PARM_DECL:
3079     case RESULT_DECL:
3080     case ERROR_MARK:
3081       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3082               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3083
3084     case BIND_EXPR:
3085       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3086
3087     default:
3088       return 0;
3089     }
3090 }
3091 \f
3092 /* Give an error for storing in something that is 'const'.  */
3093
3094 static void
3095 readonly_error (tree arg, enum lvalue_use use)
3096 {
3097   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3098               || use == lv_asm);
3099   /* Using this macro rather than (for example) arrays of messages
3100      ensures that all the format strings are checked at compile
3101      time.  */
3102 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3103                                    : (use == lv_increment ? (I)         \
3104                                    : (use == lv_decrement ? (D) : (AS))))
3105   if (TREE_CODE (arg) == COMPONENT_REF)
3106     {
3107       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3108         readonly_error (TREE_OPERAND (arg, 0), use);
3109       else
3110         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3111                              G_("increment of read-only member %qD"),
3112                              G_("decrement of read-only member %qD"),
3113                              G_("read-only member %qD used as %<asm%> output")),
3114                TREE_OPERAND (arg, 1));
3115     }
3116   else if (TREE_CODE (arg) == VAR_DECL)
3117     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3118                          G_("increment of read-only variable %qD"),
3119                          G_("decrement of read-only variable %qD"),
3120                          G_("read-only variable %qD used as %<asm%> output")),
3121            arg);
3122   else
3123     error (READONLY_MSG (G_("assignment of read-only location"),
3124                          G_("increment of read-only location"),
3125                          G_("decrement of read-only location"),
3126                          G_("read-only location used as %<asm%> output")));
3127 }
3128
3129
3130 /* Return nonzero if REF is an lvalue valid for this language;
3131    otherwise, print an error message and return zero.  USE says
3132    how the lvalue is being used and so selects the error message.  */
3133
3134 static int
3135 lvalue_or_else (tree ref, enum lvalue_use use)
3136 {
3137   int win = lvalue_p (ref);
3138
3139   if (!win)
3140     lvalue_error (use);
3141
3142   return win;
3143 }
3144 \f
3145 /* Mark EXP saying that we need to be able to take the
3146    address of it; it should not be allocated in a register.
3147    Returns true if successful.  */
3148
3149 bool
3150 c_mark_addressable (tree exp)
3151 {
3152   tree x = exp;
3153
3154   while (1)
3155     switch (TREE_CODE (x))
3156       {
3157       case COMPONENT_REF:
3158         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3159           {
3160             error
3161               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3162             return false;
3163           }
3164
3165         /* ... fall through ...  */
3166
3167       case ADDR_EXPR:
3168       case ARRAY_REF:
3169       case REALPART_EXPR:
3170       case IMAGPART_EXPR:
3171         x = TREE_OPERAND (x, 0);
3172         break;
3173
3174       case COMPOUND_LITERAL_EXPR:
3175       case CONSTRUCTOR:
3176         TREE_ADDRESSABLE (x) = 1;
3177         return true;
3178
3179       case VAR_DECL:
3180       case CONST_DECL:
3181       case PARM_DECL:
3182       case RESULT_DECL:
3183         if (C_DECL_REGISTER (x)
3184             && DECL_NONLOCAL (x))
3185           {
3186             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3187               {
3188                 error
3189                   ("global register variable %qD used in nested function", x);
3190                 return false;
3191               }
3192             pedwarn ("register variable %qD used in nested function", x);
3193           }
3194         else if (C_DECL_REGISTER (x))
3195           {
3196             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3197               error ("address of global register variable %qD requested", x);
3198             else
3199               error ("address of register variable %qD requested", x);
3200             return false;
3201           }
3202
3203         /* drops in */
3204       case FUNCTION_DECL:
3205         TREE_ADDRESSABLE (x) = 1;
3206         /* drops out */
3207       default:
3208         return true;
3209     }
3210 }
3211 \f
3212 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3213
3214 tree
3215 build_conditional_expr (tree ifexp, tree op1, tree op2)
3216 {
3217   tree type1;
3218   tree type2;
3219   enum tree_code code1;
3220   enum tree_code code2;
3221   tree result_type = NULL;
3222   tree orig_op1 = op1, orig_op2 = op2;
3223
3224   /* Promote both alternatives.  */
3225
3226   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3227     op1 = default_conversion (op1);
3228   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3229     op2 = default_conversion (op2);
3230
3231   if (TREE_CODE (ifexp) == ERROR_MARK
3232       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3233       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3234     return error_mark_node;
3235
3236   type1 = TREE_TYPE (op1);
3237   code1 = TREE_CODE (type1);
3238   type2 = TREE_TYPE (op2);
3239   code2 = TREE_CODE (type2);
3240
3241   /* C90 does not permit non-lvalue arrays in conditional expressions.
3242      In C99 they will be pointers by now.  */
3243   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3244     {
3245       error ("non-lvalue array in conditional expression");
3246       return error_mark_node;
3247     }
3248
3249   /* Quickly detect the usual case where op1 and op2 have the same type
3250      after promotion.  */
3251   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3252     {
3253       if (type1 == type2)
3254         result_type = type1;
3255       else
3256         result_type = TYPE_MAIN_VARIANT (type1);
3257     }
3258   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3259             || code1 == COMPLEX_TYPE)
3260            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3261                || code2 == COMPLEX_TYPE))
3262     {
3263       result_type = c_common_type (type1, type2);
3264
3265       /* If -Wsign-compare, warn here if type1 and type2 have
3266          different signedness.  We'll promote the signed to unsigned
3267          and later code won't know it used to be different.
3268          Do this check on the original types, so that explicit casts
3269          will be considered, but default promotions won't.  */
3270       if (warn_sign_compare && !skip_evaluation)
3271         {
3272           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3273           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3274
3275           if (unsigned_op1 ^ unsigned_op2)
3276             {
3277               bool ovf;
3278
3279               /* Do not warn if the result type is signed, since the
3280                  signed type will only be chosen if it can represent
3281                  all the values of the unsigned type.  */
3282               if (!TYPE_UNSIGNED (result_type))
3283                 /* OK */;
3284               /* Do not warn if the signed quantity is an unsuffixed
3285                  integer literal (or some static constant expression
3286                  involving such literals) and it is non-negative.  */
3287               else if ((unsigned_op2
3288                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3289                        || (unsigned_op1
3290                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3291                 /* OK */;
3292               else
3293                 warning (0, "signed and unsigned type in conditional expression");
3294             }
3295         }
3296     }
3297   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3298     {
3299       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3300         pedwarn ("ISO C forbids conditional expr with only one void side");
3301       result_type = void_type_node;
3302     }
3303   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3304     {
3305       if (comp_target_types (type1, type2))
3306         result_type = common_pointer_type (type1, type2);
3307       else if (null_pointer_constant_p (orig_op1))
3308         result_type = qualify_type (type2, type1);
3309       else if (null_pointer_constant_p (orig_op2))
3310         result_type = qualify_type (type1, type2);
3311       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3312         {
3313           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3314             pedwarn ("ISO C forbids conditional expr between "
3315                      "%<void *%> and function pointer");
3316           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3317                                                           TREE_TYPE (type2)));
3318         }
3319       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3320         {
3321           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3322             pedwarn ("ISO C forbids conditional expr between "
3323                      "%<void *%> and function pointer");
3324           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3325                                                           TREE_TYPE (type1)));
3326         }
3327       else
3328         {
3329           pedwarn ("pointer type mismatch in conditional expression");
3330           result_type = build_pointer_type (void_type_node);
3331         }
3332     }
3333   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3334     {
3335       if (!null_pointer_constant_p (orig_op2))
3336         pedwarn ("pointer/integer type mismatch in conditional expression");
3337       else
3338         {
3339           op2 = null_pointer_node;
3340         }
3341       result_type = type1;
3342     }
3343   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3344     {
3345       if (!null_pointer_constant_p (orig_op1))
3346         pedwarn ("pointer/integer type mismatch in conditional expression");
3347       else
3348         {
3349           op1 = null_pointer_node;
3350         }
3351       result_type = type2;
3352     }
3353
3354   if (!result_type)
3355     {
3356       if (flag_cond_mismatch)
3357         result_type = void_type_node;
3358       else
3359         {
3360           error ("type mismatch in conditional expression");
3361           return error_mark_node;
3362         }
3363     }
3364
3365   /* Merge const and volatile flags of the incoming types.  */
3366   result_type
3367     = build_type_variant (result_type,
3368                           TREE_READONLY (op1) || TREE_READONLY (op2),
3369                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3370
3371   if (result_type != TREE_TYPE (op1))
3372     op1 = convert_and_check (result_type, op1);
3373   if (result_type != TREE_TYPE (op2))
3374     op2 = convert_and_check (result_type, op2);
3375
3376   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3377 }
3378 \f
3379 /* Return a compound expression that performs two expressions and
3380    returns the value of the second of them.  */
3381
3382 tree
3383 build_compound_expr (tree expr1, tree expr2)
3384 {
3385   if (!TREE_SIDE_EFFECTS (expr1))
3386     {
3387       /* The left-hand operand of a comma expression is like an expression
3388          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3389          any side-effects, unless it was explicitly cast to (void).  */
3390       if (warn_unused_value)
3391         {
3392           if (VOID_TYPE_P (TREE_TYPE (expr1))
3393               && (TREE_CODE (expr1) == NOP_EXPR
3394                   || TREE_CODE (expr1) == CONVERT_EXPR))
3395             ; /* (void) a, b */
3396           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3397                    && TREE_CODE (expr1) == COMPOUND_EXPR
3398                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3399                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
3400             ; /* (void) a, (void) b, c */
3401           else
3402             warning (0, "left-hand operand of comma expression has no effect");
3403         }
3404     }
3405
3406   /* With -Wunused, we should also warn if the left-hand operand does have
3407      side-effects, but computes a value which is not used.  For example, in
3408      `foo() + bar(), baz()' the result of the `+' operator is not used,
3409      so we should issue a warning.  */
3410   else if (warn_unused_value)
3411     warn_if_unused_value (expr1, input_location);
3412
3413   if (expr2 == error_mark_node)
3414     return error_mark_node;
3415
3416   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3417 }
3418
3419 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3420
3421 tree
3422 build_c_cast (tree type, tree expr)
3423 {
3424   tree value = expr;
3425
3426   if (type == error_mark_node || expr == error_mark_node)
3427     return error_mark_node;
3428
3429   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3430      only in <protocol> qualifications.  But when constructing cast expressions,
3431      the protocols do matter and must be kept around.  */
3432   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3433     return build1 (NOP_EXPR, type, expr);
3434
3435   type = TYPE_MAIN_VARIANT (type);
3436
3437   if (TREE_CODE (type) == ARRAY_TYPE)
3438     {
3439       error ("cast specifies array type");
3440       return error_mark_node;
3441     }
3442
3443   if (TREE_CODE (type) == FUNCTION_TYPE)
3444     {
3445       error ("cast specifies function type");
3446       return error_mark_node;
3447     }
3448
3449   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3450     {
3451       if (pedantic)
3452         {
3453           if (TREE_CODE (type) == RECORD_TYPE
3454               || TREE_CODE (type) == UNION_TYPE)
3455             pedwarn ("ISO C forbids casting nonscalar to the same type");
3456         }
3457     }
3458   else if (TREE_CODE (type) == UNION_TYPE)
3459     {
3460       tree field;
3461
3462       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3463         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3464                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3465           break;
3466
3467       if (field)
3468         {
3469           tree t;
3470
3471           if (pedantic)
3472             pedwarn ("ISO C forbids casts to union type");
3473           t = digest_init (type,
3474                            build_constructor_single (type, field, value),
3475                            true, 0);
3476           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3477           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3478           return t;
3479         }
3480       error ("cast to union type from type not present in union");
3481       return error_mark_node;
3482     }
3483   else
3484     {
3485       tree otype, ovalue;
3486
3487       if (type == void_type_node)
3488         return build1 (CONVERT_EXPR, type, value);
3489
3490       otype = TREE_TYPE (value);
3491
3492       /* Optionally warn about potentially worrisome casts.  */
3493
3494       if (warn_cast_qual
3495           && TREE_CODE (type) == POINTER_TYPE
3496           && TREE_CODE (otype) == POINTER_TYPE)
3497         {
3498           tree in_type = type;
3499           tree in_otype = otype;
3500           int added = 0;
3501           int discarded = 0;
3502
3503           /* Check that the qualifiers on IN_TYPE are a superset of
3504              the qualifiers of IN_OTYPE.  The outermost level of
3505              POINTER_TYPE nodes is uninteresting and we stop as soon
3506              as we hit a non-POINTER_TYPE node on either type.  */
3507           do
3508             {
3509               in_otype = TREE_TYPE (in_otype);
3510               in_type = TREE_TYPE (in_type);
3511
3512               /* GNU C allows cv-qualified function types.  'const'
3513                  means the function is very pure, 'volatile' means it
3514                  can't return.  We need to warn when such qualifiers
3515                  are added, not when they're taken away.  */
3516               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3517                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3518                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3519               else
3520                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3521             }
3522           while (TREE_CODE (in_type) == POINTER_TYPE
3523                  && TREE_CODE (in_otype) == POINTER_TYPE);
3524
3525           if (added)
3526             warning (0, "cast adds new qualifiers to function type");
3527
3528           if (discarded)
3529             /* There are qualifiers present in IN_OTYPE that are not
3530                present in IN_TYPE.  */
3531             warning (0, "cast discards qualifiers from pointer target type");
3532         }
3533
3534       /* Warn about possible alignment problems.  */
3535       if (STRICT_ALIGNMENT
3536           && TREE_CODE (type) == POINTER_TYPE
3537           && TREE_CODE (otype) == POINTER_TYPE
3538           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3539           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3540           /* Don't warn about opaque types, where the actual alignment
3541              restriction is unknown.  */
3542           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3543                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3544                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3545           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3546         warning (OPT_Wcast_align,
3547                  "cast increases required alignment of target type");
3548
3549       if (TREE_CODE (type) == INTEGER_TYPE
3550           && TREE_CODE (otype) == POINTER_TYPE
3551           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3552       /* Unlike conversion of integers to pointers, where the
3553          warning is disabled for converting constants because
3554          of cases such as SIG_*, warn about converting constant
3555          pointers to integers. In some cases it may cause unwanted
3556          sign extension, and a warning is appropriate.  */
3557         warning (OPT_Wpointer_to_int_cast,
3558                  "cast from pointer to integer of different size");
3559
3560       if (TREE_CODE (value) == CALL_EXPR
3561           && TREE_CODE (type) != TREE_CODE (otype))
3562         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3563                  "to non-matching type %qT", otype, type);
3564
3565       if (TREE_CODE (type) == POINTER_TYPE
3566           && TREE_CODE (otype) == INTEGER_TYPE
3567           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3568           /* Don't warn about converting any constant.  */
3569           && !TREE_CONSTANT (value))
3570         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3571                  "of different size");
3572
3573       strict_aliasing_warning (otype, type, expr);
3574
3575       /* If pedantic, warn for conversions between function and object
3576          pointer types, except for converting a null pointer constant
3577          to function pointer type.  */
3578       if (pedantic
3579           && TREE_CODE (type) == POINTER_TYPE
3580           && TREE_CODE (otype) == POINTER_TYPE
3581           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3582           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3583         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3584
3585       if (pedantic
3586           && TREE_CODE (type) == POINTER_TYPE
3587           && TREE_CODE (otype) == POINTER_TYPE
3588           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3589           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3590           && !null_pointer_constant_p (value))
3591         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3592
3593       ovalue = value;
3594       value = convert (type, value);
3595
3596       /* Ignore any integer overflow caused by the cast.  */
3597       if (TREE_CODE (value) == INTEGER_CST)
3598         {
3599           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3600             {
3601               if (!TREE_OVERFLOW (value))
3602                 {
3603                   /* Avoid clobbering a shared constant.  */
3604                   value = copy_node (value);
3605                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3606                 }
3607             }
3608           else if (TREE_OVERFLOW (value))
3609             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3610             value = build_int_cst_wide (TREE_TYPE (value),
3611                                         TREE_INT_CST_LOW (value),
3612                                         TREE_INT_CST_HIGH (value));
3613         }
3614     }
3615
3616   /* Don't let a cast be an lvalue.  */
3617   if (value == expr)
3618     value = non_lvalue (value);
3619
3620   return value;
3621 }
3622
3623 /* Interpret a cast of expression EXPR to type TYPE.  */
3624 tree
3625 c_cast_expr (struct c_type_name *type_name, tree expr)
3626 {
3627   tree type;
3628   int saved_wsp = warn_strict_prototypes;
3629
3630   /* This avoids warnings about unprototyped casts on
3631      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3632   if (TREE_CODE (expr) == INTEGER_CST)
3633     warn_strict_prototypes = 0;
3634   type = groktypename (type_name);
3635   warn_strict_prototypes = saved_wsp;
3636
3637   return build_c_cast (type, expr);
3638 }
3639 \f
3640 /* Build an assignment expression of lvalue LHS from value RHS.
3641    MODIFYCODE is the code for a binary operator that we use
3642    to combine the old value of LHS with RHS to get the new value.
3643    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3644
3645 tree
3646 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3647 {
3648   tree result;
3649   tree newrhs;
3650   tree lhstype = TREE_TYPE (lhs);
3651   tree olhstype = lhstype;
3652
3653   /* Types that aren't fully specified cannot be used in assignments.  */
3654   lhs = require_complete_type (lhs);
3655
3656   /* Avoid duplicate error messages from operands that had errors.  */
3657   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3658     return error_mark_node;
3659
3660   if (!lvalue_or_else (lhs, lv_assign))
3661     return error_mark_node;
3662
3663   STRIP_TYPE_NOPS (rhs);
3664
3665   newrhs = rhs;
3666
3667   /* If a binary op has been requested, combine the old LHS value with the RHS
3668      producing the value we should actually store into the LHS.  */
3669
3670   if (modifycode != NOP_EXPR)
3671     {
3672       lhs = stabilize_reference (lhs);
3673       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3674     }
3675
3676   /* Give an error for storing in something that is 'const'.  */
3677
3678   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3679       || ((TREE_CODE (lhstype) == RECORD_TYPE
3680            || TREE_CODE (lhstype) == UNION_TYPE)
3681           && C_TYPE_FIELDS_READONLY (lhstype)))
3682     {
3683       readonly_error (lhs, lv_assign);
3684       return error_mark_node;
3685     }
3686
3687   /* If storing into a structure or union member,
3688      it has probably been given type `int'.
3689      Compute the type that would go with
3690      the actual amount of storage the member occupies.  */
3691
3692   if (TREE_CODE (lhs) == COMPONENT_REF
3693       && (TREE_CODE (lhstype) == INTEGER_TYPE
3694           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3695           || TREE_CODE (lhstype) == REAL_TYPE
3696           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3697     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3698
3699   /* If storing in a field that is in actuality a short or narrower than one,
3700      we must store in the field in its actual type.  */
3701
3702   if (lhstype != TREE_TYPE (lhs))
3703     {
3704       lhs = copy_node (lhs);
3705       TREE_TYPE (lhs) = lhstype;
3706     }
3707
3708   /* Convert new value to destination type.  */
3709
3710   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3711                                    NULL_TREE, NULL_TREE, 0);
3712   if (TREE_CODE (newrhs) == ERROR_MARK)
3713     return error_mark_node;
3714
3715   /* Emit ObjC write barrier, if necessary.  */
3716   if (c_dialect_objc () && flag_objc_gc)
3717     {
3718       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3719       if (result)
3720         return result;
3721     }
3722
3723   /* Scan operands.  */
3724
3725   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3726   TREE_SIDE_EFFECTS (result) = 1;
3727
3728   /* If we got the LHS in a different type for storing in,
3729      convert the result back to the nominal type of LHS
3730      so that the value we return always has the same type
3731      as the LHS argument.  */
3732
3733   if (olhstype == TREE_TYPE (result))
3734     return result;
3735   return convert_for_assignment (olhstype, result, ic_assign,
3736                                  NULL_TREE, NULL_TREE, 0);
3737 }
3738 \f
3739 /* Convert value RHS to type TYPE as preparation for an assignment
3740    to an lvalue of type TYPE.
3741    The real work of conversion is done by `convert'.
3742    The purpose of this function is to generate error messages
3743    for assignments that are not allowed in C.
3744    ERRTYPE says whether it is argument passing, assignment,
3745    initialization or return.
3746
3747    FUNCTION is a tree for the function being called.
3748    PARMNUM is the number of the argument, for printing in error messages.  */
3749
3750 static tree
3751 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3752                         tree fundecl, tree function, int parmnum)
3753 {
3754   enum tree_code codel = TREE_CODE (type);
3755   tree rhstype;
3756   enum tree_code coder;
3757   tree rname = NULL_TREE;
3758   bool objc_ok = false;
3759
3760   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3761     {
3762       tree selector;
3763       /* Change pointer to function to the function itself for
3764          diagnostics.  */
3765       if (TREE_CODE (function) == ADDR_EXPR
3766           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3767         function = TREE_OPERAND (function, 0);
3768
3769       /* Handle an ObjC selector specially for diagnostics.  */
3770       selector = objc_message_selector ();
3771       rname = function;
3772       if (selector && parmnum > 2)
3773         {
3774           rname = selector;
3775           parmnum -= 2;
3776         }
3777     }
3778
3779   /* This macro is used to emit diagnostics to ensure that all format
3780      strings are complete sentences, visible to gettext and checked at
3781      compile time.  */
3782 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3783   do {                                          \
3784     switch (errtype)                            \
3785       {                                         \
3786       case ic_argpass:                          \
3787         pedwarn (AR, parmnum, rname);           \
3788         break;                                  \
3789       case ic_argpass_nonproto:                 \
3790         warning (0, AR, parmnum, rname);                \
3791         break;                                  \
3792       case ic_assign:                           \
3793         pedwarn (AS);                           \
3794         break;                                  \
3795       case ic_init:                             \
3796         pedwarn (IN);                           \
3797         break;                                  \
3798       case ic_return:                           \
3799         pedwarn (RE);                           \
3800         break;                                  \
3801       default:                                  \
3802         gcc_unreachable ();                     \
3803       }                                         \
3804   } while (0)
3805
3806   STRIP_TYPE_NOPS (rhs);
3807
3808   if (optimize && TREE_CODE (rhs) == VAR_DECL
3809            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3810     rhs = decl_constant_value_for_broken_optimization (rhs);
3811
3812   rhstype = TREE_TYPE (rhs);
3813   coder = TREE_CODE (rhstype);
3814
3815   if (coder == ERROR_MARK)
3816     return error_mark_node;
3817
3818   if (c_dialect_objc ())
3819     {
3820       int parmno;
3821
3822       switch (errtype)
3823         {
3824         case ic_return:
3825           parmno = 0;
3826           break;
3827
3828         case ic_assign:
3829           parmno = -1;
3830           break;
3831
3832         case ic_init:
3833           parmno = -2;
3834           break;
3835
3836         default:
3837           parmno = parmnum;
3838           break;
3839         }
3840
3841       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3842     }
3843
3844   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3845     return rhs;
3846
3847   if (coder == VOID_TYPE)
3848     {
3849       /* Except for passing an argument to an unprototyped function,
3850          this is a constraint violation.  When passing an argument to
3851          an unprototyped function, it is compile-time undefined;
3852          making it a constraint in that case was rejected in
3853          DR#252.  */
3854       error ("void value not ignored as it ought to be");
3855       return error_mark_node;
3856     }
3857   /* A type converts to a reference to it.
3858      This code doesn't fully support references, it's just for the
3859      special case of va_start and va_copy.  */
3860   if (codel == REFERENCE_TYPE
3861       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3862     {
3863       if (!lvalue_p (rhs))
3864         {
3865           error ("cannot pass rvalue to reference parameter");
3866           return error_mark_node;
3867         }
3868       if (!c_mark_addressable (rhs))
3869         return error_mark_node;
3870       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3871
3872       /* We already know that these two types are compatible, but they
3873          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3874          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3875          likely to be va_list, a typedef to __builtin_va_list, which
3876          is different enough that it will cause problems later.  */
3877       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3878         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3879
3880       rhs = build1 (NOP_EXPR, type, rhs);
3881       return rhs;
3882     }
3883   /* Some types can interconvert without explicit casts.  */
3884   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3885            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
3886     return convert (type, rhs);
3887   /* Arithmetic types all interconvert, and enum is treated like int.  */
3888   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3889             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3890             || codel == BOOLEAN_TYPE)
3891            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3892                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3893                || coder == BOOLEAN_TYPE))
3894     return convert_and_check (type, rhs);
3895
3896   /* Conversion to a transparent union from its member types.
3897      This applies only to function arguments.  */
3898   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3899            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3900     {
3901       tree memb, marginal_memb = NULL_TREE;
3902
3903       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3904         {
3905           tree memb_type = TREE_TYPE (memb);
3906
3907           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3908                          TYPE_MAIN_VARIANT (rhstype)))
3909             break;
3910
3911           if (TREE_CODE (memb_type) != POINTER_TYPE)
3912             continue;
3913
3914           if (coder == POINTER_TYPE)
3915             {
3916               tree ttl = TREE_TYPE (memb_type);
3917               tree ttr = TREE_TYPE (rhstype);
3918
3919               /* Any non-function converts to a [const][volatile] void *
3920                  and vice versa; otherwise, targets must be the same.
3921                  Meanwhile, the lhs target must have all the qualifiers of
3922                  the rhs.  */
3923               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3924                   || comp_target_types (memb_type, rhstype))
3925                 {
3926                   /* If this type won't generate any warnings, use it.  */
3927                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3928                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3929                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3930                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3931                              == TYPE_QUALS (ttr))
3932                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3933                              == TYPE_QUALS (ttl))))
3934                     break;
3935
3936                   /* Keep looking for a better type, but remember this one.  */
3937                   if (!marginal_memb)
3938                     marginal_memb = memb;
3939                 }
3940             }
3941
3942           /* Can convert integer zero to any pointer type.  */
3943           if (null_pointer_constant_p (rhs))
3944             {
3945               rhs = null_pointer_node;
3946               break;
3947             }
3948         }
3949
3950       if (memb || marginal_memb)
3951         {
3952           if (!memb)
3953             {
3954               /* We have only a marginally acceptable member type;
3955                  it needs a warning.  */
3956               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3957               tree ttr = TREE_TYPE (rhstype);
3958
3959               /* Const and volatile mean something different for function
3960                  types, so the usual warnings are not appropriate.  */
3961               if (TREE_CODE (ttr) == FUNCTION_TYPE
3962                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3963                 {
3964                   /* Because const and volatile on functions are
3965                      restrictions that say the function will not do
3966                      certain things, it is okay to use a const or volatile
3967                      function where an ordinary one is wanted, but not
3968                      vice-versa.  */
3969                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3970                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3971                                             "makes qualified function "
3972                                             "pointer from unqualified"),
3973                                          G_("assignment makes qualified "
3974                                             "function pointer from "
3975                                             "unqualified"),
3976                                          G_("initialization makes qualified "
3977                                             "function pointer from "
3978                                             "unqualified"),
3979                                          G_("return makes qualified function "
3980                                             "pointer from unqualified"));
3981                 }
3982               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3983                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3984                                         "qualifiers from pointer target type"),
3985                                      G_("assignment discards qualifiers "
3986                                         "from pointer target type"),
3987                                      G_("initialization discards qualifiers "
3988                                         "from pointer target type"),
3989                                      G_("return discards qualifiers from "
3990                                         "pointer target type"));
3991
3992               memb = marginal_memb;
3993             }
3994
3995           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3996             pedwarn ("ISO C prohibits argument conversion to union type");
3997
3998           return build_constructor_single (type, memb, rhs);
3999         }
4000     }
4001
4002   /* Conversions among pointers */
4003   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4004            && (coder == codel))
4005     {
4006       tree ttl = TREE_TYPE (type);
4007       tree ttr = TREE_TYPE (rhstype);
4008       tree mvl = ttl;
4009       tree mvr = ttr;
4010       bool is_opaque_pointer;
4011       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4012
4013       if (TREE_CODE (mvl) != ARRAY_TYPE)
4014         mvl = TYPE_MAIN_VARIANT (mvl);
4015       if (TREE_CODE (mvr) != ARRAY_TYPE)
4016         mvr = TYPE_MAIN_VARIANT (mvr);
4017       /* Opaque pointers are treated like void pointers.  */
4018       is_opaque_pointer = (targetm.vector_opaque_p (type)
4019                            || targetm.vector_opaque_p (rhstype))
4020         && TREE_CODE (ttl) == VECTOR_TYPE
4021         && TREE_CODE (ttr) == VECTOR_TYPE;
4022
4023       /* C++ does not allow the implicit conversion void* -> T*.  However,
4024          for the purpose of reducing the number of false positives, we
4025          tolerate the special case of
4026
4027                 int *p = NULL;
4028
4029          where NULL is typically defined in C to be '(void *) 0'.  */
4030       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4031         warning (OPT_Wc___compat, "request for implicit conversion from "
4032                  "%qT to %qT not permitted in C++", rhstype, type);
4033
4034       /* Check if the right-hand side has a format attribute but the
4035          left-hand side doesn't.  */
4036       if (warn_missing_format_attribute
4037           && check_missing_format_attribute (type, rhstype))
4038         {
4039           switch (errtype)
4040           {
4041           case ic_argpass:
4042           case ic_argpass_nonproto:
4043             warning (OPT_Wmissing_format_attribute,
4044                      "argument %d of %qE might be "
4045                      "a candidate for a format attribute",
4046                      parmnum, rname);
4047             break;
4048           case ic_assign:
4049             warning (OPT_Wmissing_format_attribute,
4050                      "assignment left-hand side might be "
4051                      "a candidate for a format attribute");
4052             break;
4053           case ic_init:
4054             warning (OPT_Wmissing_format_attribute,
4055                      "initialization left-hand side might be "
4056                      "a candidate for a format attribute");
4057             break;
4058           case ic_return:
4059             warning (OPT_Wmissing_format_attribute,
4060                      "return type might be "
4061                      "a candidate for a format attribute");
4062             break;
4063           default:
4064             gcc_unreachable ();
4065           }
4066         }
4067
4068       /* Any non-function converts to a [const][volatile] void *
4069          and vice versa; otherwise, targets must be the same.
4070          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4071       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4072           || (target_cmp = comp_target_types (type, rhstype))
4073           || is_opaque_pointer
4074           || (c_common_unsigned_type (mvl)
4075               == c_common_unsigned_type (mvr)))
4076         {
4077           if (pedantic
4078               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4079                   ||
4080                   (VOID_TYPE_P (ttr)
4081                    && !null_pointer_constant_p (rhs)
4082                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4083             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4084                                     "%qE between function pointer "
4085                                     "and %<void *%>"),
4086                                  G_("ISO C forbids assignment between "
4087                                     "function pointer and %<void *%>"),
4088                                  G_("ISO C forbids initialization between "
4089                                     "function pointer and %<void *%>"),
4090                                  G_("ISO C forbids return between function "
4091                                     "pointer and %<void *%>"));
4092           /* Const and volatile mean something different for function types,
4093              so the usual warnings are not appropriate.  */
4094           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4095                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4096             {
4097               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4098                 {
4099                   /* Types differing only by the presence of the 'volatile'
4100                      qualifier are acceptable if the 'volatile' has been added
4101                      in by the Objective-C EH machinery.  */
4102                   if (!objc_type_quals_match (ttl, ttr))
4103                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4104                                             "qualifiers from pointer target type"),
4105                                          G_("assignment discards qualifiers "
4106                                             "from pointer target type"),
4107                                          G_("initialization discards qualifiers "
4108                                             "from pointer target type"),
4109                                          G_("return discards qualifiers from "
4110                                             "pointer target type"));
4111                 }
4112               /* If this is not a case of ignoring a mismatch in signedness,
4113                  no warning.  */
4114               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4115                        || target_cmp)
4116                 ;
4117               /* If there is a mismatch, do warn.  */
4118               else if (warn_pointer_sign)
4119                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4120                                         "%d of %qE differ in signedness"),
4121                                      G_("pointer targets in assignment "
4122                                         "differ in signedness"),
4123                                      G_("pointer targets in initialization "
4124                                         "differ in signedness"),
4125                                      G_("pointer targets in return differ "
4126                                         "in signedness"));
4127             }
4128           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4129                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4130             {
4131               /* Because const and volatile on functions are restrictions
4132                  that say the function will not do certain things,
4133                  it is okay to use a const or volatile function
4134                  where an ordinary one is wanted, but not vice-versa.  */
4135               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4136                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4137                                         "qualified function pointer "
4138                                         "from unqualified"),
4139                                      G_("assignment makes qualified function "
4140                                         "pointer from unqualified"),
4141                                      G_("initialization makes qualified "
4142                                         "function pointer from unqualified"),
4143                                      G_("return makes qualified function "
4144                                         "pointer from unqualified"));
4145             }
4146         }
4147       else
4148         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4149         if (!objc_ok)
4150           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4151                                   "incompatible pointer type"),
4152                                G_("assignment from incompatible pointer type"),
4153                                G_("initialization from incompatible "
4154                                   "pointer type"),
4155                                G_("return from incompatible pointer type"));
4156
4157       return convert (type, rhs);
4158     }
4159   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4160     {
4161       /* ??? This should not be an error when inlining calls to
4162          unprototyped functions.  */
4163       error ("invalid use of non-lvalue array");
4164       return error_mark_node;
4165     }
4166   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4167     {
4168       /* An explicit constant 0 can convert to a pointer,
4169          or one that results from arithmetic, even including
4170          a cast to integer type.  */
4171       if (!null_pointer_constant_p (rhs))
4172         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4173                                 "pointer from integer without a cast"),
4174                              G_("assignment makes pointer from integer "
4175                                 "without a cast"),
4176                              G_("initialization makes pointer from "
4177                                 "integer without a cast"),
4178                              G_("return makes pointer from integer "
4179                                 "without a cast"));
4180
4181       return convert (type, rhs);
4182     }
4183   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4184     {
4185       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4186                               "from pointer without a cast"),
4187                            G_("assignment makes integer from pointer "
4188                               "without a cast"),
4189                            G_("initialization makes integer from pointer "
4190                               "without a cast"),
4191                            G_("return makes integer from pointer "
4192                               "without a cast"));
4193       return convert (type, rhs);
4194     }
4195   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4196     return convert (type, rhs);
4197
4198   switch (errtype)
4199     {
4200     case ic_argpass:
4201     case ic_argpass_nonproto:
4202       /* ??? This should not be an error when inlining calls to
4203          unprototyped functions.  */
4204       error ("incompatible type for argument %d of %qE", parmnum, rname);
4205       break;
4206     case ic_assign:
4207       error ("incompatible types in assignment");
4208       break;
4209     case ic_init:
4210       error ("incompatible types in initialization");
4211       break;
4212     case ic_return:
4213       error ("incompatible types in return");
4214       break;
4215     default:
4216       gcc_unreachable ();
4217     }
4218
4219   return error_mark_node;
4220 }
4221
4222 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4223    is used for error and warning reporting and indicates which argument
4224    is being processed.  */
4225
4226 tree
4227 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4228 {
4229   tree ret, type;
4230
4231   /* If FN was prototyped at the call site, the value has been converted
4232      already in convert_arguments.
4233      However, we might see a prototype now that was not in place when
4234      the function call was seen, so check that the VALUE actually matches
4235      PARM before taking an early exit.  */
4236   if (!value
4237       || (TYPE_ARG_TYPES (TREE_TYPE (fn))
4238           && (TYPE_MAIN_VARIANT (TREE_TYPE (parm))
4239               == TYPE_MAIN_VARIANT (TREE_TYPE (value)))))
4240     return value;
4241
4242   type = TREE_TYPE (parm);
4243   ret = convert_for_assignment (type, value,
4244                                 ic_argpass_nonproto, fn,
4245                                 fn, argnum);
4246   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4247       && INTEGRAL_TYPE_P (type)
4248       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4249     ret = default_conversion (ret);
4250   return ret;
4251 }
4252 \f
4253 /* If VALUE is a compound expr all of whose expressions are constant, then
4254    return its value.  Otherwise, return error_mark_node.
4255
4256    This is for handling COMPOUND_EXPRs as initializer elements
4257    which is allowed with a warning when -pedantic is specified.  */
4258
4259 static tree
4260 valid_compound_expr_initializer (tree value, tree endtype)
4261 {
4262   if (TREE_CODE (value) == COMPOUND_EXPR)
4263     {
4264       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4265           == error_mark_node)
4266         return error_mark_node;
4267       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4268                                               endtype);
4269     }
4270   else if (!initializer_constant_valid_p (value, endtype))
4271     return error_mark_node;
4272   else
4273     return value;
4274 }
4275 \f
4276 /* Perform appropriate conversions on the initial value of a variable,
4277    store it in the declaration DECL,
4278    and print any error messages that are appropriate.
4279    If the init is invalid, store an ERROR_MARK.  */
4280
4281 void
4282 store_init_value (tree decl, tree init)
4283 {
4284   tree value, type;
4285
4286   /* If variable's type was invalidly declared, just ignore it.  */
4287
4288   type = TREE_TYPE (decl);
4289   if (TREE_CODE (type) == ERROR_MARK)
4290     return;
4291
4292   /* Digest the specified initializer into an expression.  */
4293
4294   value = digest_init (type, init, true, TREE_STATIC (decl));
4295
4296   /* Store the expression if valid; else report error.  */
4297
4298   if (!in_system_header
4299       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4300     warning (OPT_Wtraditional, "traditional C rejects automatic "
4301              "aggregate initialization");
4302
4303   DECL_INITIAL (decl) = value;
4304
4305   /* ANSI wants warnings about out-of-range constant initializers.  */
4306   STRIP_TYPE_NOPS (value);
4307   if (TREE_STATIC (decl))
4308     constant_expression_warning (value);
4309
4310   /* Check if we need to set array size from compound literal size.  */
4311   if (TREE_CODE (type) == ARRAY_TYPE
4312       && TYPE_DOMAIN (type) == 0
4313       && value != error_mark_node)
4314     {
4315       tree inside_init = init;
4316
4317       STRIP_TYPE_NOPS (inside_init);
4318       inside_init = fold (inside_init);
4319
4320       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4321         {
4322           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4323
4324           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4325             {
4326               /* For int foo[] = (int [3]){1}; we need to set array size
4327                  now since later on array initializer will be just the
4328                  brace enclosed list of the compound literal.  */
4329               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4330               TREE_TYPE (decl) = type;
4331               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4332               layout_type (type);
4333               layout_decl (cldecl, 0);
4334             }
4335         }
4336     }
4337 }
4338 \f
4339 /* Methods for storing and printing names for error messages.  */
4340
4341 /* Implement a spelling stack that allows components of a name to be pushed
4342    and popped.  Each element on the stack is this structure.  */
4343
4344 struct spelling
4345 {
4346   int kind;
4347   union
4348     {
4349       unsigned HOST_WIDE_INT i;
4350       const char *s;
4351     } u;
4352 };
4353
4354 #define SPELLING_STRING 1
4355 #define SPELLING_MEMBER 2
4356 #define SPELLING_BOUNDS 3
4357
4358 static struct spelling *spelling;       /* Next stack element (unused).  */
4359 static struct spelling *spelling_base;  /* Spelling stack base.  */
4360 static int spelling_size;               /* Size of the spelling stack.  */
4361
4362 /* Macros to save and restore the spelling stack around push_... functions.
4363    Alternative to SAVE_SPELLING_STACK.  */
4364
4365 #define SPELLING_DEPTH() (spelling - spelling_base)
4366 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4367
4368 /* Push an element on the spelling stack with type KIND and assign VALUE
4369    to MEMBER.  */
4370
4371 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4372 {                                                                       \
4373   int depth = SPELLING_DEPTH ();                                        \
4374                                                                         \
4375   if (depth >= spelling_size)                                           \
4376     {                                                                   \
4377       spelling_size += 10;                                              \
4378       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4379                                   spelling_size);                       \
4380       RESTORE_SPELLING_DEPTH (depth);                                   \
4381     }                                                                   \
4382                                                                         \
4383   spelling->kind = (KIND);                                              \
4384   spelling->MEMBER = (VALUE);                                           \
4385   spelling++;                                                           \
4386 }
4387
4388 /* Push STRING on the stack.  Printed literally.  */
4389
4390 static void
4391 push_string (const char *string)
4392 {
4393   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4394 }
4395
4396 /* Push a member name on the stack.  Printed as '.' STRING.  */
4397
4398 static void
4399 push_member_name (tree decl)
4400 {
4401   const char *const string
4402     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4403   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4404 }
4405
4406 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4407
4408 static void
4409 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4410 {
4411   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4412 }
4413
4414 /* Compute the maximum size in bytes of the printed spelling.  */
4415
4416 static int
4417 spelling_length (void)
4418 {
4419   int size = 0;
4420   struct spelling *p;
4421
4422   for (p = spelling_base; p < spelling; p++)
4423     {
4424       if (p->kind == SPELLING_BOUNDS)
4425         size += 25;
4426       else
4427         size += strlen (p->u.s) + 1;
4428     }
4429
4430   return size;
4431 }
4432
4433 /* Print the spelling to BUFFER and return it.  */
4434
4435 static char *
4436 print_spelling (char *buffer)
4437 {
4438   char *d = buffer;
4439   struct spelling *p;
4440
4441   for (p = spelling_base; p < spelling; p++)
4442     if (p->kind == SPELLING_BOUNDS)
4443       {
4444         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4445         d += strlen (d);
4446       }
4447     else
4448       {
4449         const char *s;
4450         if (p->kind == SPELLING_MEMBER)
4451           *d++ = '.';
4452         for (s = p->u.s; (*d = *s++); d++)
4453           ;
4454       }
4455   *d++ = '\0';
4456   return buffer;
4457 }
4458
4459 /* Issue an error message for a bad initializer component.
4460    MSGID identifies the message.
4461    The component name is taken from the spelling stack.  */
4462
4463 void
4464 error_init (const char *msgid)
4465 {
4466   char *ofwhat;
4467
4468   error ("%s", _(msgid));
4469   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4470   if (*ofwhat)
4471     error ("(near initialization for %qs)", ofwhat);
4472 }
4473
4474 /* Issue a pedantic warning for a bad initializer component.
4475    MSGID identifies the message.
4476    The component name is taken from the spelling stack.  */
4477
4478 void
4479 pedwarn_init (const char *msgid)
4480 {
4481   char *ofwhat;
4482
4483   pedwarn ("%s", _(msgid));
4484   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4485   if (*ofwhat)
4486     pedwarn ("(near initialization for %qs)", ofwhat);
4487 }
4488
4489 /* Issue a warning for a bad initializer component.
4490    MSGID identifies the message.
4491    The component name is taken from the spelling stack.  */
4492
4493 static void
4494 warning_init (const char *msgid)
4495 {
4496   char *ofwhat;
4497
4498   warning (0, "%s", _(msgid));
4499   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4500   if (*ofwhat)
4501     warning (0, "(near initialization for %qs)", ofwhat);
4502 }
4503 \f
4504 /* If TYPE is an array type and EXPR is a parenthesized string
4505    constant, warn if pedantic that EXPR is being used to initialize an
4506    object of type TYPE.  */
4507
4508 void
4509 maybe_warn_string_init (tree type, struct c_expr expr)
4510 {
4511   if (pedantic
4512       && TREE_CODE (type) == ARRAY_TYPE
4513       && TREE_CODE (expr.value) == STRING_CST
4514       && expr.original_code != STRING_CST)
4515     pedwarn_init ("array initialized from parenthesized string constant");
4516 }
4517
4518 /* Digest the parser output INIT as an initializer for type TYPE.
4519    Return a C expression of type TYPE to represent the initial value.
4520
4521    If INIT is a string constant, STRICT_STRING is true if it is
4522    unparenthesized or we should not warn here for it being parenthesized.
4523    For other types of INIT, STRICT_STRING is not used.
4524
4525    REQUIRE_CONSTANT requests an error if non-constant initializers or
4526    elements are seen.  */
4527
4528 static tree
4529 digest_init (tree type, tree init, bool strict_string, int require_constant)
4530 {
4531   enum tree_code code = TREE_CODE (type);
4532   tree inside_init = init;
4533
4534   if (type == error_mark_node
4535       || !init
4536       || init == error_mark_node
4537       || TREE_TYPE (init) == error_mark_node)
4538     return error_mark_node;
4539
4540   STRIP_TYPE_NOPS (inside_init);
4541
4542   inside_init = fold (inside_init);
4543
4544   /* Initialization of an array of chars from a string constant
4545      optionally enclosed in braces.  */
4546
4547   if (code == ARRAY_TYPE && inside_init
4548       && TREE_CODE (inside_init) == STRING_CST)
4549     {
4550       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4551       /* Note that an array could be both an array of character type
4552          and an array of wchar_t if wchar_t is signed char or unsigned
4553          char.  */
4554       bool char_array = (typ1 == char_type_node
4555                          || typ1 == signed_char_type_node
4556                          || typ1 == unsigned_char_type_node);
4557       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4558       if (char_array || wchar_array)
4559         {
4560           struct c_expr expr;
4561           bool char_string;
4562           expr.value = inside_init;
4563           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4564           maybe_warn_string_init (type, expr);
4565
4566           char_string
4567             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4568                == char_type_node);
4569
4570           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4571                          TYPE_MAIN_VARIANT (type)))
4572             return inside_init;
4573
4574           if (!wchar_array && !char_string)
4575             {
4576               error_init ("char-array initialized from wide string");
4577               return error_mark_node;
4578             }
4579           if (char_string && !char_array)
4580             {
4581               error_init ("wchar_t-array initialized from non-wide string");
4582               return error_mark_node;
4583             }
4584
4585           TREE_TYPE (inside_init) = type;
4586           if (TYPE_DOMAIN (type) != 0
4587               && TYPE_SIZE (type) != 0
4588               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4589               /* Subtract 1 (or sizeof (wchar_t))
4590                  because it's ok to ignore the terminating null char
4591                  that is counted in the length of the constant.  */
4592               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4593                                        TREE_STRING_LENGTH (inside_init)
4594                                        - ((TYPE_PRECISION (typ1)
4595                                            != TYPE_PRECISION (char_type_node))
4596                                           ? (TYPE_PRECISION (wchar_type_node)
4597                                              / BITS_PER_UNIT)
4598                                           : 1)))
4599             pedwarn_init ("initializer-string for array of chars is too long");
4600
4601           return inside_init;
4602         }
4603       else if (INTEGRAL_TYPE_P (typ1))
4604         {
4605           error_init ("array of inappropriate type initialized "
4606                       "from string constant");
4607           return error_mark_node;
4608         }
4609     }
4610
4611   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4612      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4613      below and handle as a constructor.  */
4614   if (code == VECTOR_TYPE
4615       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4616       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4617       && TREE_CONSTANT (inside_init))
4618     {
4619       if (TREE_CODE (inside_init) == VECTOR_CST
4620           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4621                         TYPE_MAIN_VARIANT (type)))
4622         return inside_init;
4623
4624       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4625         {
4626           unsigned HOST_WIDE_INT ix;
4627           tree value;
4628           bool constant_p = true;
4629
4630           /* Iterate through elements and check if all constructor
4631              elements are *_CSTs.  */
4632           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4633             if (!CONSTANT_CLASS_P (value))
4634               {
4635                 constant_p = false;
4636                 break;
4637               }
4638
4639           if (constant_p)
4640             return build_vector_from_ctor (type,
4641                                            CONSTRUCTOR_ELTS (inside_init));
4642         }
4643     }
4644
4645   /* Any type can be initialized
4646      from an expression of the same type, optionally with braces.  */
4647
4648   if (inside_init && TREE_TYPE (inside_init) != 0
4649       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4650                      TYPE_MAIN_VARIANT (type))
4651           || (code == ARRAY_TYPE
4652               && comptypes (TREE_TYPE (inside_init), type))
4653           || (code == VECTOR_TYPE
4654               && comptypes (TREE_TYPE (inside_init), type))
4655           || (code == POINTER_TYPE
4656               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4657               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4658                             TREE_TYPE (type)))))
4659     {
4660       if (code == POINTER_TYPE)
4661         {
4662           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4663             {
4664               if (TREE_CODE (inside_init) == STRING_CST
4665                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4666                 inside_init = array_to_pointer_conversion (inside_init);
4667               else
4668                 {
4669                   error_init ("invalid use of non-lvalue array");
4670                   return error_mark_node;
4671                 }
4672             }
4673         }
4674
4675       if (code == VECTOR_TYPE)
4676         /* Although the types are compatible, we may require a
4677            conversion.  */
4678         inside_init = convert (type, inside_init);
4679
4680       if (require_constant
4681           && (code == VECTOR_TYPE || !flag_isoc99)
4682           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4683         {
4684           /* As an extension, allow initializing objects with static storage
4685              duration with compound literals (which are then treated just as
4686              the brace enclosed list they contain).  Also allow this for
4687              vectors, as we can only assign them with compound literals.  */
4688           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4689           inside_init = DECL_INITIAL (decl);
4690         }
4691
4692       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4693           && TREE_CODE (inside_init) != CONSTRUCTOR)
4694         {
4695           error_init ("array initialized from non-constant array expression");
4696           return error_mark_node;
4697         }
4698
4699       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4700         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4701
4702       /* Compound expressions can only occur here if -pedantic or
4703          -pedantic-errors is specified.  In the later case, we always want
4704          an error.  In the former case, we simply want a warning.  */
4705       if (require_constant && pedantic
4706           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4707         {
4708           inside_init
4709             = valid_compound_expr_initializer (inside_init,
4710                                                TREE_TYPE (inside_init));
4711           if (inside_init == error_mark_node)
4712             error_init ("initializer element is not constant");
4713           else
4714             pedwarn_init ("initializer element is not constant");
4715           if (flag_pedantic_errors)
4716             inside_init = error_mark_node;
4717         }
4718       else if (require_constant
4719                && !initializer_constant_valid_p (inside_init,
4720                                                  TREE_TYPE (inside_init)))
4721         {
4722           error_init ("initializer element is not constant");
4723           inside_init = error_mark_node;
4724         }
4725
4726       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4727       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4728         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4729                                               NULL_TREE, 0);
4730       return inside_init;
4731     }
4732
4733   /* Handle scalar types, including conversions.  */
4734
4735   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4736       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4737       || code == VECTOR_TYPE)
4738     {
4739       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4740           && (TREE_CODE (init) == STRING_CST
4741               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4742         init = array_to_pointer_conversion (init);
4743       inside_init
4744         = convert_for_assignment (type, init, ic_init,
4745                                   NULL_TREE, NULL_TREE, 0);
4746
4747       /* Check to see if we have already given an error message.  */
4748       if (inside_init == error_mark_node)
4749         ;
4750       else if (require_constant && !TREE_CONSTANT (inside_init))
4751         {
4752           error_init ("initializer element is not constant");
4753           inside_init = error_mark_node;
4754         }
4755       else if (require_constant
4756                && !initializer_constant_valid_p (inside_init,
4757                                                  TREE_TYPE (inside_init)))
4758         {
4759           error_init ("initializer element is not computable at load time");
4760           inside_init = error_mark_node;
4761         }
4762
4763       return inside_init;
4764     }
4765
4766   /* Come here only for records and arrays.  */
4767
4768   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4769     {
4770       error_init ("variable-sized object may not be initialized");
4771       return error_mark_node;
4772     }
4773
4774   error_init ("invalid initializer");
4775   return error_mark_node;
4776 }
4777 \f
4778 /* Handle initializers that use braces.  */
4779
4780 /* Type of object we are accumulating a constructor for.
4781    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4782 static tree constructor_type;
4783
4784 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4785    left to fill.  */
4786 static tree constructor_fields;
4787
4788 /* For an ARRAY_TYPE, this is the specified index
4789    at which to store the next element we get.  */
4790 static tree constructor_index;
4791
4792 /* For an ARRAY_TYPE, this is the maximum index.  */
4793 static tree constructor_max_index;
4794
4795 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4796 static tree constructor_unfilled_fields;
4797
4798 /* For an ARRAY_TYPE, this is the index of the first element
4799    not yet written out.  */
4800 static tree constructor_unfilled_index;
4801
4802 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4803    This is so we can generate gaps between fields, when appropriate.  */
4804 static tree constructor_bit_index;
4805
4806 /* If we are saving up the elements rather than allocating them,
4807    this is the list of elements so far (in reverse order,
4808    most recent first).  */
4809 static VEC(constructor_elt,gc) *constructor_elements;
4810
4811 /* 1 if constructor should be incrementally stored into a constructor chain,
4812    0 if all the elements should be kept in AVL tree.  */
4813 static int constructor_incremental;
4814
4815 /* 1 if so far this constructor's elements are all compile-time constants.  */
4816 static int constructor_constant;
4817
4818 /* 1 if so far this constructor's elements are all valid address constants.  */
4819 static int constructor_simple;
4820
4821 /* 1 if this constructor is erroneous so far.  */
4822 static int constructor_erroneous;
4823
4824 /* Structure for managing pending initializer elements, organized as an
4825    AVL tree.  */
4826
4827 struct init_node
4828 {
4829   struct init_node *left, *right;
4830   struct init_node *parent;
4831   int balance;
4832   tree purpose;
4833   tree value;
4834 };
4835
4836 /* Tree of pending elements at this constructor level.
4837    These are elements encountered out of order
4838    which belong at places we haven't reached yet in actually
4839    writing the output.
4840    Will never hold tree nodes across GC runs.  */
4841 static struct init_node *constructor_pending_elts;
4842
4843 /* The SPELLING_DEPTH of this constructor.  */
4844 static int constructor_depth;
4845
4846 /* DECL node for which an initializer is being read.
4847    0 means we are reading a constructor expression
4848    such as (struct foo) {...}.  */
4849 static tree constructor_decl;
4850
4851 /* Nonzero if this is an initializer for a top-level decl.  */
4852 static int constructor_top_level;
4853
4854 /* Nonzero if there were any member designators in this initializer.  */
4855 static int constructor_designated;
4856
4857 /* Nesting depth of designator list.  */
4858 static int designator_depth;
4859
4860 /* Nonzero if there were diagnosed errors in this designator list.  */
4861 static int designator_erroneous;
4862
4863 \f
4864 /* This stack has a level for each implicit or explicit level of
4865    structuring in the initializer, including the outermost one.  It
4866    saves the values of most of the variables above.  */
4867
4868 struct constructor_range_stack;
4869
4870 struct constructor_stack
4871 {
4872   struct constructor_stack *next;
4873   tree type;
4874   tree fields;
4875   tree index;
4876   tree max_index;
4877   tree unfilled_index;
4878   tree unfilled_fields;
4879   tree bit_index;
4880   VEC(constructor_elt,gc) *elements;
4881   struct init_node *pending_elts;
4882   int offset;
4883   int depth;
4884   /* If value nonzero, this value should replace the entire
4885      constructor at this level.  */
4886   struct c_expr replacement_value;
4887   struct constructor_range_stack *range_stack;
4888   char constant;
4889   char simple;
4890   char implicit;
4891   char erroneous;
4892   char outer;
4893   char incremental;
4894   char designated;
4895 };
4896
4897 static struct constructor_stack *constructor_stack;
4898
4899 /* This stack represents designators from some range designator up to
4900    the last designator in the list.  */
4901
4902 struct constructor_range_stack
4903 {
4904   struct constructor_range_stack *next, *prev;
4905   struct constructor_stack *stack;
4906   tree range_start;
4907   tree index;
4908   tree range_end;
4909   tree fields;
4910 };
4911
4912 static struct constructor_range_stack *constructor_range_stack;
4913
4914 /* This stack records separate initializers that are nested.
4915    Nested initializers can't happen in ANSI C, but GNU C allows them
4916    in cases like { ... (struct foo) { ... } ... }.  */
4917
4918 struct initializer_stack
4919 {
4920   struct initializer_stack *next;
4921   tree decl;
4922   struct constructor_stack *constructor_stack;
4923   struct constructor_range_stack *constructor_range_stack;
4924   VEC(constructor_elt,gc) *elements;
4925   struct spelling *spelling;
4926   struct spelling *spelling_base;
4927   int spelling_size;
4928   char top_level;
4929   char require_constant_value;
4930   char require_constant_elements;
4931 };
4932
4933 static struct initializer_stack *initializer_stack;
4934 \f
4935 /* Prepare to parse and output the initializer for variable DECL.  */
4936
4937 void
4938 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4939 {
4940   const char *locus;
4941   struct initializer_stack *p = XNEW (struct initializer_stack);
4942
4943   p->decl = constructor_decl;
4944   p->require_constant_value = require_constant_value;
4945   p->require_constant_elements = require_constant_elements;
4946   p->constructor_stack = constructor_stack;
4947   p->constructor_range_stack = constructor_range_stack;
4948   p->elements = constructor_elements;
4949   p->spelling = spelling;
4950   p->spelling_base = spelling_base;
4951   p->spelling_size = spelling_size;
4952   p->top_level = constructor_top_level;
4953   p->next = initializer_stack;
4954   initializer_stack = p;
4955
4956   constructor_decl = decl;
4957   constructor_designated = 0;
4958   constructor_top_level = top_level;
4959
4960   if (decl != 0 && decl != error_mark_node)
4961     {
4962       require_constant_value = TREE_STATIC (decl);
4963       require_constant_elements
4964         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4965            /* For a scalar, you can always use any value to initialize,
4966               even within braces.  */
4967            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4968                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4969                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4970                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4971       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4972     }
4973   else
4974     {
4975       require_constant_value = 0;
4976       require_constant_elements = 0;
4977       locus = "(anonymous)";
4978     }
4979
4980   constructor_stack = 0;
4981   constructor_range_stack = 0;
4982
4983   missing_braces_mentioned = 0;
4984
4985   spelling_base = 0;
4986   spelling_size = 0;
4987   RESTORE_SPELLING_DEPTH (0);
4988
4989   if (locus)
4990     push_string (locus);
4991 }
4992
4993 void
4994 finish_init (void)
4995 {
4996   struct initializer_stack *p = initializer_stack;
4997
4998   /* Free the whole constructor stack of this initializer.  */
4999   while (constructor_stack)
5000     {
5001       struct constructor_stack *q = constructor_stack;
5002       constructor_stack = q->next;
5003       free (q);
5004     }
5005
5006   gcc_assert (!constructor_range_stack);
5007
5008   /* Pop back to the data of the outer initializer (if any).  */
5009   free (spelling_base);
5010
5011   constructor_decl = p->decl;
5012   require_constant_value = p->require_constant_value;
5013   require_constant_elements = p->require_constant_elements;
5014   constructor_stack = p->constructor_stack;
5015   constructor_range_stack = p->constructor_range_stack;
5016   constructor_elements = p->elements;
5017   spelling = p->spelling;
5018   spelling_base = p->spelling_base;
5019   spelling_size = p->spelling_size;
5020   constructor_top_level = p->top_level;
5021   initializer_stack = p->next;
5022   free (p);
5023 }
5024 \f
5025 /* Call here when we see the initializer is surrounded by braces.
5026    This is instead of a call to push_init_level;
5027    it is matched by a call to pop_init_level.
5028
5029    TYPE is the type to initialize, for a constructor expression.
5030    For an initializer for a decl, TYPE is zero.  */
5031
5032 void
5033 really_start_incremental_init (tree type)
5034 {
5035   struct constructor_stack *p = XNEW (struct constructor_stack);
5036
5037   if (type == 0)
5038     type = TREE_TYPE (constructor_decl);
5039
5040   if (targetm.vector_opaque_p (type))
5041     error ("opaque vector types cannot be initialized");
5042
5043   p->type = constructor_type;
5044   p->fields = constructor_fields;
5045   p->index = constructor_index;
5046   p->max_index = constructor_max_index;
5047   p->unfilled_index = constructor_unfilled_index;
5048   p->unfilled_fields = constructor_unfilled_fields;
5049   p->bit_index = constructor_bit_index;
5050   p->elements = constructor_elements;
5051   p->constant = constructor_constant;
5052   p->simple = constructor_simple;
5053   p->erroneous = constructor_erroneous;
5054   p->pending_elts = constructor_pending_elts;
5055   p->depth = constructor_depth;
5056   p->replacement_value.value = 0;
5057   p->replacement_value.original_code = ERROR_MARK;
5058   p->implicit = 0;
5059   p->range_stack = 0;
5060   p->outer = 0;
5061   p->incremental = constructor_incremental;
5062   p->designated = constructor_designated;
5063   p->next = 0;
5064   constructor_stack = p;
5065
5066   constructor_constant = 1;
5067   constructor_simple = 1;
5068   constructor_depth = SPELLING_DEPTH ();
5069   constructor_elements = 0;
5070   constructor_pending_elts = 0;
5071   constructor_type = type;
5072   constructor_incremental = 1;
5073   constructor_designated = 0;
5074   designator_depth = 0;
5075   designator_erroneous = 0;
5076
5077   if (TREE_CODE (constructor_type) == RECORD_TYPE
5078       || TREE_CODE (constructor_type) == UNION_TYPE)
5079     {
5080       constructor_fields = TYPE_FIELDS (constructor_type);
5081       /* Skip any nameless bit fields at the beginning.  */
5082       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5083              && DECL_NAME (constructor_fields) == 0)
5084         constructor_fields = TREE_CHAIN (constructor_fields);
5085
5086       constructor_unfilled_fields = constructor_fields;
5087       constructor_bit_index = bitsize_zero_node;
5088     }
5089   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5090     {
5091       if (TYPE_DOMAIN (constructor_type))
5092         {
5093           constructor_max_index
5094             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5095
5096           /* Detect non-empty initializations of zero-length arrays.  */
5097           if (constructor_max_index == NULL_TREE
5098               && TYPE_SIZE (constructor_type))
5099             constructor_max_index = build_int_cst (NULL_TREE, -1);
5100
5101           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5102              to initialize VLAs will cause a proper error; avoid tree
5103              checking errors as well by setting a safe value.  */
5104           if (constructor_max_index
5105               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5106             constructor_max_index = build_int_cst (NULL_TREE, -1);
5107
5108           constructor_index
5109             = convert (bitsizetype,
5110                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5111         }
5112       else
5113         {
5114           constructor_index = bitsize_zero_node;
5115           constructor_max_index = NULL_TREE;
5116         }
5117
5118       constructor_unfilled_index = constructor_index;
5119     }
5120   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5121     {
5122       /* Vectors are like simple fixed-size arrays.  */
5123       constructor_max_index =
5124         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5125       constructor_index = bitsize_zero_node;
5126       constructor_unfilled_index = constructor_index;
5127     }
5128   else
5129     {
5130       /* Handle the case of int x = {5}; */
5131       constructor_fields = constructor_type;
5132       constructor_unfilled_fields = constructor_type;
5133     }
5134 }
5135 \f
5136 /* Push down into a subobject, for initialization.
5137    If this is for an explicit set of braces, IMPLICIT is 0.
5138    If it is because the next element belongs at a lower level,
5139    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5140
5141 void
5142 push_init_level (int implicit)
5143 {
5144   struct constructor_stack *p;
5145   tree value = NULL_TREE;
5146
5147   /* If we've exhausted any levels that didn't have braces,
5148      pop them now.  If implicit == 1, this will have been done in
5149      process_init_element; do not repeat it here because in the case
5150      of excess initializers for an empty aggregate this leads to an
5151      infinite cycle of popping a level and immediately recreating
5152      it.  */
5153   if (implicit != 1)
5154     {
5155       while (constructor_stack->implicit)
5156         {
5157           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5158                || TREE_CODE (constructor_type) == UNION_TYPE)
5159               && constructor_fields == 0)
5160             process_init_element (pop_init_level (1));
5161           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5162                    && constructor_max_index
5163                    && tree_int_cst_lt (constructor_max_index,
5164                                        constructor_index))
5165             process_init_element (pop_init_level (1));
5166           else
5167             break;
5168         }
5169     }
5170
5171   /* Unless this is an explicit brace, we need to preserve previous
5172      content if any.  */
5173   if (implicit)
5174     {
5175       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5176            || TREE_CODE (constructor_type) == UNION_TYPE)
5177           && constructor_fields)
5178         value = find_init_member (constructor_fields);
5179       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5180         value = find_init_member (constructor_index);
5181     }
5182
5183   p = XNEW (struct constructor_stack);
5184   p->type = constructor_type;
5185   p->fields = constructor_fields;
5186   p->index = constructor_index;
5187   p->max_index = constructor_max_index;
5188   p->unfilled_index = constructor_unfilled_index;
5189   p->unfilled_fields = constructor_unfilled_fields;
5190   p->bit_index = constructor_bit_index;
5191   p->elements = constructor_elements;
5192   p->constant = constructor_constant;
5193   p->simple = constructor_simple;
5194   p->erroneous = constructor_erroneous;
5195   p->pending_elts = constructor_pending_elts;
5196   p->depth = constructor_depth;
5197   p->replacement_value.value = 0;
5198   p->replacement_value.original_code = ERROR_MARK;
5199   p->implicit = implicit;
5200   p->outer = 0;
5201   p->incremental = constructor_incremental;
5202   p->designated = constructor_designated;
5203   p->next = constructor_stack;
5204   p->range_stack = 0;
5205   constructor_stack = p;
5206
5207   constructor_constant = 1;
5208   constructor_simple = 1;
5209   constructor_depth = SPELLING_DEPTH ();
5210   constructor_elements = 0;
5211   constructor_incremental = 1;
5212   constructor_designated = 0;
5213   constructor_pending_elts = 0;
5214   if (!implicit)
5215     {
5216       p->range_stack = constructor_range_stack;
5217       constructor_range_stack = 0;
5218       designator_depth = 0;
5219       designator_erroneous = 0;
5220     }
5221
5222   /* Don't die if an entire brace-pair level is superfluous
5223      in the containing level.  */
5224   if (constructor_type == 0)
5225     ;
5226   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5227            || TREE_CODE (constructor_type) == UNION_TYPE)
5228     {
5229       /* Don't die if there are extra init elts at the end.  */
5230       if (constructor_fields == 0)
5231         constructor_type = 0;
5232       else
5233         {
5234           constructor_type = TREE_TYPE (constructor_fields);
5235           push_member_name (constructor_fields);
5236           constructor_depth++;
5237         }
5238     }
5239   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5240     {
5241       constructor_type = TREE_TYPE (constructor_type);
5242       push_array_bounds (tree_low_cst (constructor_index, 1));
5243       constructor_depth++;
5244     }
5245
5246   if (constructor_type == 0)
5247     {
5248       error_init ("extra brace group at end of initializer");
5249       constructor_fields = 0;
5250       constructor_unfilled_fields = 0;
5251       return;
5252     }
5253
5254   if (value && TREE_CODE (value) == CONSTRUCTOR)
5255     {
5256       constructor_constant = TREE_CONSTANT (value);
5257       constructor_simple = TREE_STATIC (value);
5258       constructor_elements = CONSTRUCTOR_ELTS (value);
5259       if (!VEC_empty (constructor_elt, constructor_elements)
5260           && (TREE_CODE (constructor_type) == RECORD_TYPE
5261               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5262         set_nonincremental_init ();
5263     }
5264
5265   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5266     {
5267       missing_braces_mentioned = 1;
5268       warning_init ("missing braces around initializer");
5269     }
5270
5271   if (TREE_CODE (constructor_type) == RECORD_TYPE
5272            || TREE_CODE (constructor_type) == UNION_TYPE)
5273     {
5274       constructor_fields = TYPE_FIELDS (constructor_type);
5275       /* Skip any nameless bit fields at the beginning.  */
5276       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5277              && DECL_NAME (constructor_fields) == 0)
5278         constructor_fields = TREE_CHAIN (constructor_fields);
5279
5280       constructor_unfilled_fields = constructor_fields;
5281       constructor_bit_index = bitsize_zero_node;
5282     }
5283   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5284     {
5285       /* Vectors are like simple fixed-size arrays.  */
5286       constructor_max_index =
5287         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5288       constructor_index = convert (bitsizetype, integer_zero_node);
5289       constructor_unfilled_index = constructor_index;
5290     }
5291   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5292     {
5293       if (TYPE_DOMAIN (constructor_type))
5294         {
5295           constructor_max_index
5296             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5297
5298           /* Detect non-empty initializations of zero-length arrays.  */
5299           if (constructor_max_index == NULL_TREE
5300               && TYPE_SIZE (constructor_type))
5301             constructor_max_index = build_int_cst (NULL_TREE, -1);
5302
5303           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5304              to initialize VLAs will cause a proper error; avoid tree
5305              checking errors as well by setting a safe value.  */
5306           if (constructor_max_index
5307               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5308             constructor_max_index = build_int_cst (NULL_TREE, -1);
5309
5310           constructor_index
5311             = convert (bitsizetype,
5312                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5313         }
5314       else
5315         constructor_index = bitsize_zero_node;
5316
5317       constructor_unfilled_index = constructor_index;
5318       if (value && TREE_CODE (value) == STRING_CST)
5319         {
5320           /* We need to split the char/wchar array into individual
5321              characters, so that we don't have to special case it
5322              everywhere.  */
5323           set_nonincremental_init_from_string (value);
5324         }
5325     }
5326   else
5327     {
5328       if (constructor_type != error_mark_node)
5329         warning_init ("braces around scalar initializer");
5330       constructor_fields = constructor_type;
5331       constructor_unfilled_fields = constructor_type;
5332     }
5333 }
5334
5335 /* At the end of an implicit or explicit brace level,
5336    finish up that level of constructor.  If a single expression
5337    with redundant braces initialized that level, return the
5338    c_expr structure for that expression.  Otherwise, the original_code
5339    element is set to ERROR_MARK.
5340    If we were outputting the elements as they are read, return 0 as the value
5341    from inner levels (process_init_element ignores that),
5342    but return error_mark_node as the value from the outermost level
5343    (that's what we want to put in DECL_INITIAL).
5344    Otherwise, return a CONSTRUCTOR expression as the value.  */
5345
5346 struct c_expr
5347 pop_init_level (int implicit)
5348 {
5349   struct constructor_stack *p;
5350   struct c_expr ret;
5351   ret.value = 0;
5352   ret.original_code = ERROR_MARK;
5353
5354   if (implicit == 0)
5355     {
5356       /* When we come to an explicit close brace,
5357          pop any inner levels that didn't have explicit braces.  */
5358       while (constructor_stack->implicit)
5359         process_init_element (pop_init_level (1));
5360
5361       gcc_assert (!constructor_range_stack);
5362     }
5363
5364   /* Now output all pending elements.  */
5365   constructor_incremental = 1;
5366   output_pending_init_elements (1);
5367
5368   p = constructor_stack;
5369
5370   /* Error for initializing a flexible array member, or a zero-length
5371      array member in an inappropriate context.  */
5372   if (constructor_type && constructor_fields
5373       && TREE_CODE (constructor_type) == ARRAY_TYPE
5374       && TYPE_DOMAIN (constructor_type)
5375       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5376     {
5377       /* Silently discard empty initializations.  The parser will
5378          already have pedwarned for empty brackets.  */
5379       if (integer_zerop (constructor_unfilled_index))
5380         constructor_type = NULL_TREE;
5381       else
5382         {
5383           gcc_assert (!TYPE_SIZE (constructor_type));
5384
5385           if (constructor_depth > 2)
5386             error_init ("initialization of flexible array member in a nested context");
5387           else if (pedantic)
5388             pedwarn_init ("initialization of a flexible array member");
5389
5390           /* We have already issued an error message for the existence
5391              of a flexible array member not at the end of the structure.
5392              Discard the initializer so that we do not die later.  */
5393           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5394             constructor_type = NULL_TREE;
5395         }
5396     }
5397
5398   /* Warn when some struct elements are implicitly initialized to zero.  */
5399   if (warn_missing_field_initializers
5400       && constructor_type
5401       && TREE_CODE (constructor_type) == RECORD_TYPE
5402       && constructor_unfilled_fields)
5403     {
5404         /* Do not warn for flexible array members or zero-length arrays.  */
5405         while (constructor_unfilled_fields
5406                && (!DECL_SIZE (constructor_unfilled_fields)
5407                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5408           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5409
5410         /* Do not warn if this level of the initializer uses member
5411            designators; it is likely to be deliberate.  */
5412         if (constructor_unfilled_fields && !constructor_designated)
5413           {
5414             push_member_name (constructor_unfilled_fields);
5415             warning_init ("missing initializer");
5416             RESTORE_SPELLING_DEPTH (constructor_depth);
5417           }
5418     }
5419
5420   /* Pad out the end of the structure.  */
5421   if (p->replacement_value.value)
5422     /* If this closes a superfluous brace pair,
5423        just pass out the element between them.  */
5424     ret = p->replacement_value;
5425   else if (constructor_type == 0)
5426     ;
5427   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5428            && TREE_CODE (constructor_type) != UNION_TYPE
5429            && TREE_CODE (constructor_type) != ARRAY_TYPE
5430            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5431     {
5432       /* A nonincremental scalar initializer--just return
5433          the element, after verifying there is just one.  */
5434       if (VEC_empty (constructor_elt,constructor_elements))
5435         {
5436           if (!constructor_erroneous)
5437             error_init ("empty scalar initializer");
5438           ret.value = error_mark_node;
5439         }
5440       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5441         {
5442           error_init ("extra elements in scalar initializer");
5443           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5444         }
5445       else
5446         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5447     }
5448   else
5449     {
5450       if (constructor_erroneous)
5451         ret.value = error_mark_node;
5452       else
5453         {
5454           ret.value = build_constructor (constructor_type,
5455                                          constructor_elements);
5456           if (constructor_constant)
5457             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5458           if (constructor_constant && constructor_simple)
5459             TREE_STATIC (ret.value) = 1;
5460         }
5461     }
5462
5463   constructor_type = p->type;
5464   constructor_fields = p->fields;
5465   constructor_index = p->index;
5466   constructor_max_index = p->max_index;
5467   constructor_unfilled_index = p->unfilled_index;
5468   constructor_unfilled_fields = p->unfilled_fields;
5469   constructor_bit_index = p->bit_index;
5470   constructor_elements = p->elements;
5471   constructor_constant = p->constant;
5472   constructor_simple = p->simple;
5473   constructor_erroneous = p->erroneous;
5474   constructor_incremental = p->incremental;
5475   constructor_designated = p->designated;
5476   constructor_pending_elts = p->pending_elts;
5477   constructor_depth = p->depth;
5478   if (!p->implicit)
5479     constructor_range_stack = p->range_stack;
5480   RESTORE_SPELLING_DEPTH (constructor_depth);
5481
5482   constructor_stack = p->next;
5483   free (p);
5484
5485   if (ret.value == 0 && constructor_stack == 0)
5486     ret.value = error_mark_node;
5487   return ret;
5488 }
5489
5490 /* Common handling for both array range and field name designators.
5491    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5492
5493 static int
5494 set_designator (int array)
5495 {
5496   tree subtype;
5497   enum tree_code subcode;
5498
5499   /* Don't die if an entire brace-pair level is superfluous
5500      in the containing level.  */
5501   if (constructor_type == 0)
5502     return 1;
5503
5504   /* If there were errors in this designator list already, bail out
5505      silently.  */
5506   if (designator_erroneous)
5507     return 1;
5508
5509   if (!designator_depth)
5510     {
5511       gcc_assert (!constructor_range_stack);
5512
5513       /* Designator list starts at the level of closest explicit
5514          braces.  */
5515       while (constructor_stack->implicit)
5516         process_init_element (pop_init_level (1));
5517       constructor_designated = 1;
5518       return 0;
5519     }
5520
5521   switch (TREE_CODE (constructor_type))
5522     {
5523     case  RECORD_TYPE:
5524     case  UNION_TYPE:
5525       subtype = TREE_TYPE (constructor_fields);
5526       if (subtype != error_mark_node)
5527         subtype = TYPE_MAIN_VARIANT (subtype);
5528       break;
5529     case ARRAY_TYPE:
5530       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5531       break;
5532     default:
5533       gcc_unreachable ();
5534     }
5535
5536   subcode = TREE_CODE (subtype);
5537   if (array && subcode != ARRAY_TYPE)
5538     {
5539       error_init ("array index in non-array initializer");
5540       return 1;
5541     }
5542   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5543     {
5544       error_init ("field name not in record or union initializer");
5545       return 1;
5546     }
5547
5548   constructor_designated = 1;
5549   push_init_level (2);
5550   return 0;
5551 }
5552
5553 /* If there are range designators in designator list, push a new designator
5554    to constructor_range_stack.  RANGE_END is end of such stack range or
5555    NULL_TREE if there is no range designator at this level.  */
5556
5557 static void
5558 push_range_stack (tree range_end)
5559 {
5560   struct constructor_range_stack *p;
5561
5562   p = GGC_NEW (struct constructor_range_stack);
5563   p->prev = constructor_range_stack;
5564   p->next = 0;
5565   p->fields = constructor_fields;
5566   p->range_start = constructor_index;
5567   p->index = constructor_index;
5568   p->stack = constructor_stack;
5569   p->range_end = range_end;
5570   if (constructor_range_stack)
5571     constructor_range_stack->next = p;
5572   constructor_range_stack = p;
5573 }
5574
5575 /* Within an array initializer, specify the next index to be initialized.
5576    FIRST is that index.  If LAST is nonzero, then initialize a range
5577    of indices, running from FIRST through LAST.  */
5578
5579 void
5580 set_init_index (tree first, tree last)
5581 {
5582   if (set_designator (1))
5583     return;
5584
5585   designator_erroneous = 1;
5586
5587   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5588       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5589     {
5590       error_init ("array index in initializer not of integer type");
5591       return;
5592     }
5593
5594   if (TREE_CODE (first) != INTEGER_CST)
5595     error_init ("nonconstant array index in initializer");
5596   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5597     error_init ("nonconstant array index in initializer");
5598   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5599     error_init ("array index in non-array initializer");
5600   else if (tree_int_cst_sgn (first) == -1)
5601     error_init ("array index in initializer exceeds array bounds");
5602   else if (constructor_max_index
5603            && tree_int_cst_lt (constructor_max_index, first))
5604     error_init ("array index in initializer exceeds array bounds");
5605   else
5606     {
5607       constructor_index = convert (bitsizetype, first);
5608
5609       if (last)
5610         {
5611           if (tree_int_cst_equal (first, last))
5612             last = 0;
5613           else if (tree_int_cst_lt (last, first))
5614             {
5615               error_init ("empty index range in initializer");
5616               last = 0;
5617             }
5618           else
5619             {
5620               last = convert (bitsizetype, last);
5621               if (constructor_max_index != 0
5622                   && tree_int_cst_lt (constructor_max_index, last))
5623                 {
5624                   error_init ("array index range in initializer exceeds array bounds");
5625                   last = 0;
5626                 }
5627             }
5628         }
5629
5630       designator_depth++;
5631       designator_erroneous = 0;
5632       if (constructor_range_stack || last)
5633         push_range_stack (last);
5634     }
5635 }
5636
5637 /* Within a struct initializer, specify the next field to be initialized.  */
5638
5639 void
5640 set_init_label (tree fieldname)
5641 {
5642   tree tail;
5643
5644   if (set_designator (0))
5645     return;
5646
5647   designator_erroneous = 1;
5648
5649   if (TREE_CODE (constructor_type) != RECORD_TYPE
5650       && TREE_CODE (constructor_type) != UNION_TYPE)
5651     {
5652       error_init ("field name not in record or union initializer");
5653       return;
5654     }
5655
5656   for (tail = TYPE_FIELDS (constructor_type); tail;
5657        tail = TREE_CHAIN (tail))
5658     {
5659       if (DECL_NAME (tail) == fieldname)
5660         break;
5661     }
5662
5663   if (tail == 0)
5664     error ("unknown field %qE specified in initializer", fieldname);
5665   else
5666     {
5667       constructor_fields = tail;
5668       designator_depth++;
5669       designator_erroneous = 0;
5670       if (constructor_range_stack)
5671         push_range_stack (NULL_TREE);
5672     }
5673 }
5674 \f
5675 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5676    identifies the initializer, either array index or field in a structure.
5677    VALUE is the value of that index or field.  */
5678
5679 static void
5680 add_pending_init (tree purpose, tree value)
5681 {
5682   struct init_node *p, **q, *r;
5683
5684   q = &constructor_pending_elts;
5685   p = 0;
5686
5687   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5688     {
5689       while (*q != 0)
5690         {
5691           p = *q;
5692           if (tree_int_cst_lt (purpose, p->purpose))
5693             q = &p->left;
5694           else if (tree_int_cst_lt (p->purpose, purpose))
5695             q = &p->right;
5696           else
5697             {
5698               if (TREE_SIDE_EFFECTS (p->value))
5699                 warning_init ("initialized field with side-effects overwritten");
5700               else if (warn_override_init)
5701                 warning_init ("initialized field overwritten");
5702               p->value = value;
5703               return;
5704             }
5705         }
5706     }
5707   else
5708     {
5709       tree bitpos;
5710
5711       bitpos = bit_position (purpose);
5712       while (*q != NULL)
5713         {
5714           p = *q;
5715           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5716             q = &p->left;
5717           else if (p->purpose != purpose)
5718             q = &p->right;
5719           else
5720             {
5721               if (TREE_SIDE_EFFECTS (p->value))
5722                 warning_init ("initialized field with side-effects overwritten");
5723               else if (warn_override_init)
5724                 warning_init ("initialized field overwritten");
5725               p->value = value;
5726               return;
5727             }
5728         }
5729     }
5730
5731   r = GGC_NEW (struct init_node);
5732   r->purpose = purpose;
5733   r->value = value;
5734
5735   *q = r;
5736   r->parent = p;
5737   r->left = 0;
5738   r->right = 0;
5739   r->balance = 0;
5740
5741   while (p)
5742     {
5743       struct init_node *s;
5744
5745       if (r == p->left)
5746         {
5747           if (p->balance == 0)
5748             p->balance = -1;
5749           else if (p->balance < 0)
5750             {
5751               if (r->balance < 0)
5752                 {
5753                   /* L rotation.  */
5754                   p->left = r->right;
5755                   if (p->left)
5756                     p->left->parent = p;
5757                   r->right = p;
5758
5759                   p->balance = 0;
5760                   r->balance = 0;
5761
5762                   s = p->parent;
5763                   p->parent = r;
5764                   r->parent = s;
5765                   if (s)
5766                     {
5767                       if (s->left == p)
5768                         s->left = r;
5769                       else
5770                         s->right = r;
5771                     }
5772                   else
5773                     constructor_pending_elts = r;
5774                 }
5775               else
5776                 {
5777                   /* LR rotation.  */
5778                   struct init_node *t = r->right;
5779
5780                   r->right = t->left;
5781                   if (r->right)
5782                     r->right->parent = r;
5783                   t->left = r;
5784
5785                   p->left = t->right;
5786                   if (p->left)
5787                     p->left->parent = p;
5788                   t->right = p;
5789
5790                   p->balance = t->balance < 0;
5791                   r->balance = -(t->balance > 0);
5792                   t->balance = 0;
5793
5794                   s = p->parent;
5795                   p->parent = t;
5796                   r->parent = t;
5797                   t->parent = s;
5798                   if (s)
5799                     {
5800                       if (s->left == p)
5801                         s->left = t;
5802                       else
5803                         s->right = t;
5804                     }
5805                   else
5806                     constructor_pending_elts = t;
5807                 }
5808               break;
5809             }
5810           else
5811             {
5812               /* p->balance == +1; growth of left side balances the node.  */
5813               p->balance = 0;
5814               break;
5815             }
5816         }
5817       else /* r == p->right */
5818         {
5819           if (p->balance == 0)
5820             /* Growth propagation from right side.  */
5821             p->balance++;
5822           else if (p->balance > 0)
5823             {
5824               if (r->balance > 0)
5825                 {
5826                   /* R rotation.  */
5827                   p->right = r->left;
5828                   if (p->right)
5829                     p->right->parent = p;
5830                   r->left = p;
5831
5832                   p->balance = 0;
5833                   r->balance = 0;
5834
5835                   s = p->parent;
5836                   p->parent = r;
5837                   r->parent = s;
5838                   if (s)
5839                     {
5840                       if (s->left == p)
5841                         s->left = r;
5842                       else
5843                         s->right = r;
5844                     }
5845                   else
5846                     constructor_pending_elts = r;
5847                 }
5848               else /* r->balance == -1 */
5849                 {
5850                   /* RL rotation */
5851                   struct init_node *t = r->left;
5852
5853                   r->left = t->right;
5854                   if (r->left)
5855                     r->left->parent = r;
5856                   t->right = r;
5857
5858                   p->right = t->left;
5859                   if (p->right)
5860                     p->right->parent = p;
5861                   t->left = p;
5862
5863                   r->balance = (t->balance < 0);
5864                   p->balance = -(t->balance > 0);
5865                   t->balance = 0;
5866
5867                   s = p->parent;
5868                   p->parent = t;
5869                   r->parent = t;
5870                   t->parent = s;
5871                   if (s)
5872                     {
5873                       if (s->left == p)
5874                         s->left = t;
5875                       else
5876                         s->right = t;
5877                     }
5878                   else
5879                     constructor_pending_elts = t;
5880                 }
5881               break;
5882             }
5883           else
5884             {
5885               /* p->balance == -1; growth of right side balances the node.  */
5886               p->balance = 0;
5887               break;
5888             }
5889         }
5890
5891       r = p;
5892       p = p->parent;
5893     }
5894 }
5895
5896 /* Build AVL tree from a sorted chain.  */
5897
5898 static void
5899 set_nonincremental_init (void)
5900 {
5901   unsigned HOST_WIDE_INT ix;
5902   tree index, value;
5903
5904   if (TREE_CODE (constructor_type) != RECORD_TYPE
5905       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5906     return;
5907
5908   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5909     add_pending_init (index, value);
5910   constructor_elements = 0;
5911   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5912     {
5913       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5914       /* Skip any nameless bit fields at the beginning.  */
5915       while (constructor_unfilled_fields != 0
5916              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5917              && DECL_NAME (constructor_unfilled_fields) == 0)
5918         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5919
5920     }
5921   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5922     {
5923       if (TYPE_DOMAIN (constructor_type))
5924         constructor_unfilled_index
5925             = convert (bitsizetype,
5926                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5927       else
5928         constructor_unfilled_index = bitsize_zero_node;
5929     }
5930   constructor_incremental = 0;
5931 }
5932
5933 /* Build AVL tree from a string constant.  */
5934
5935 static void
5936 set_nonincremental_init_from_string (tree str)
5937 {
5938   tree value, purpose, type;
5939   HOST_WIDE_INT val[2];
5940   const char *p, *end;
5941   int byte, wchar_bytes, charwidth, bitpos;
5942
5943   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5944
5945   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5946       == TYPE_PRECISION (char_type_node))
5947     wchar_bytes = 1;
5948   else
5949     {
5950       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5951                   == TYPE_PRECISION (wchar_type_node));
5952       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5953     }
5954   charwidth = TYPE_PRECISION (char_type_node);
5955   type = TREE_TYPE (constructor_type);
5956   p = TREE_STRING_POINTER (str);
5957   end = p + TREE_STRING_LENGTH (str);
5958
5959   for (purpose = bitsize_zero_node;
5960        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5961        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5962     {
5963       if (wchar_bytes == 1)
5964         {
5965           val[1] = (unsigned char) *p++;
5966           val[0] = 0;
5967         }
5968       else
5969         {
5970           val[0] = 0;
5971           val[1] = 0;
5972           for (byte = 0; byte < wchar_bytes; byte++)
5973             {
5974               if (BYTES_BIG_ENDIAN)
5975                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5976               else
5977                 bitpos = byte * charwidth;
5978               val[bitpos < HOST_BITS_PER_WIDE_INT]
5979                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5980                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5981             }
5982         }
5983
5984       if (!TYPE_UNSIGNED (type))
5985         {
5986           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5987           if (bitpos < HOST_BITS_PER_WIDE_INT)
5988             {
5989               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5990                 {
5991                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5992                   val[0] = -1;
5993                 }
5994             }
5995           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5996             {
5997               if (val[1] < 0)
5998                 val[0] = -1;
5999             }
6000           else if (val[0] & (((HOST_WIDE_INT) 1)
6001                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6002             val[0] |= ((HOST_WIDE_INT) -1)
6003                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6004         }
6005
6006       value = build_int_cst_wide (type, val[1], val[0]);
6007       add_pending_init (purpose, value);
6008     }
6009
6010   constructor_incremental = 0;
6011 }
6012
6013 /* Return value of FIELD in pending initializer or zero if the field was
6014    not initialized yet.  */
6015
6016 static tree
6017 find_init_member (tree field)
6018 {
6019   struct init_node *p;
6020
6021   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6022     {
6023       if (constructor_incremental
6024           && tree_int_cst_lt (field, constructor_unfilled_index))
6025         set_nonincremental_init ();
6026
6027       p = constructor_pending_elts;
6028       while (p)
6029         {
6030           if (tree_int_cst_lt (field, p->purpose))
6031             p = p->left;
6032           else if (tree_int_cst_lt (p->purpose, field))
6033             p = p->right;
6034           else
6035             return p->value;
6036         }
6037     }
6038   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6039     {
6040       tree bitpos = bit_position (field);
6041
6042       if (constructor_incremental
6043           && (!constructor_unfilled_fields
6044               || tree_int_cst_lt (bitpos,
6045                                   bit_position (constructor_unfilled_fields))))
6046         set_nonincremental_init ();
6047
6048       p = constructor_pending_elts;
6049       while (p)
6050         {
6051           if (field == p->purpose)
6052             return p->value;
6053           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6054             p = p->left;
6055           else
6056             p = p->right;
6057         }
6058     }
6059   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6060     {
6061       if (!VEC_empty (constructor_elt, constructor_elements)
6062           && (VEC_last (constructor_elt, constructor_elements)->index
6063               == field))
6064         return VEC_last (constructor_elt, constructor_elements)->value;
6065     }
6066   return 0;
6067 }
6068
6069 /* "Output" the next constructor element.
6070    At top level, really output it to assembler code now.
6071    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6072    TYPE is the data type that the containing data type wants here.
6073    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6074    If VALUE is a string constant, STRICT_STRING is true if it is
6075    unparenthesized or we should not warn here for it being parenthesized.
6076    For other types of VALUE, STRICT_STRING is not used.
6077
6078    PENDING if non-nil means output pending elements that belong
6079    right after this element.  (PENDING is normally 1;
6080    it is 0 while outputting pending elements, to avoid recursion.)  */
6081
6082 static void
6083 output_init_element (tree value, bool strict_string, tree type, tree field,
6084                      int pending)
6085 {
6086   constructor_elt *celt;
6087
6088   if (type == error_mark_node || value == error_mark_node)
6089     {
6090       constructor_erroneous = 1;
6091       return;
6092     }
6093   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6094       && (TREE_CODE (value) == STRING_CST
6095           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6096       && !(TREE_CODE (value) == STRING_CST
6097            && TREE_CODE (type) == ARRAY_TYPE
6098            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6099       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6100                      TYPE_MAIN_VARIANT (type)))
6101     value = array_to_pointer_conversion (value);
6102
6103   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6104       && require_constant_value && !flag_isoc99 && pending)
6105     {
6106       /* As an extension, allow initializing objects with static storage
6107          duration with compound literals (which are then treated just as
6108          the brace enclosed list they contain).  */
6109       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6110       value = DECL_INITIAL (decl);
6111     }
6112
6113   if (value == error_mark_node)
6114     constructor_erroneous = 1;
6115   else if (!TREE_CONSTANT (value))
6116     constructor_constant = 0;
6117   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6118            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6119                 || TREE_CODE (constructor_type) == UNION_TYPE)
6120                && DECL_C_BIT_FIELD (field)
6121                && TREE_CODE (value) != INTEGER_CST))
6122     constructor_simple = 0;
6123
6124   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6125     {
6126       if (require_constant_value)
6127         {
6128           error_init ("initializer element is not constant");
6129           value = error_mark_node;
6130         }
6131       else if (require_constant_elements)
6132         pedwarn ("initializer element is not computable at load time");
6133     }
6134
6135   /* If this field is empty (and not at the end of structure),
6136      don't do anything other than checking the initializer.  */
6137   if (field
6138       && (TREE_TYPE (field) == error_mark_node
6139           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6140               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6141               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6142                   || TREE_CHAIN (field)))))
6143     return;
6144
6145   value = digest_init (type, value, strict_string, require_constant_value);
6146   if (value == error_mark_node)
6147     {
6148       constructor_erroneous = 1;
6149       return;
6150     }
6151
6152   /* If this element doesn't come next in sequence,
6153      put it on constructor_pending_elts.  */
6154   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6155       && (!constructor_incremental
6156           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6157     {
6158       if (constructor_incremental
6159           && tree_int_cst_lt (field, constructor_unfilled_index))
6160         set_nonincremental_init ();
6161
6162       add_pending_init (field, value);
6163       return;
6164     }
6165   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6166            && (!constructor_incremental
6167                || field != constructor_unfilled_fields))
6168     {
6169       /* We do this for records but not for unions.  In a union,
6170          no matter which field is specified, it can be initialized
6171          right away since it starts at the beginning of the union.  */
6172       if (constructor_incremental)
6173         {
6174           if (!constructor_unfilled_fields)
6175             set_nonincremental_init ();
6176           else
6177             {
6178               tree bitpos, unfillpos;
6179
6180               bitpos = bit_position (field);
6181               unfillpos = bit_position (constructor_unfilled_fields);
6182
6183               if (tree_int_cst_lt (bitpos, unfillpos))
6184                 set_nonincremental_init ();
6185             }
6186         }
6187
6188       add_pending_init (field, value);
6189       return;
6190     }
6191   else if (TREE_CODE (constructor_type) == UNION_TYPE
6192            && !VEC_empty (constructor_elt, constructor_elements))
6193     {
6194       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6195                                        constructor_elements)->value))
6196         warning_init ("initialized field with side-effects overwritten");
6197       else if (warn_override_init)
6198         warning_init ("initialized field overwritten");
6199
6200       /* We can have just one union field set.  */
6201       constructor_elements = 0;
6202     }
6203
6204   /* Otherwise, output this element either to
6205      constructor_elements or to the assembler file.  */
6206
6207   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6208   celt->index = field;
6209   celt->value = value;
6210
6211   /* Advance the variable that indicates sequential elements output.  */
6212   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6213     constructor_unfilled_index
6214       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6215                     bitsize_one_node);
6216   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6217     {
6218       constructor_unfilled_fields
6219         = TREE_CHAIN (constructor_unfilled_fields);
6220
6221       /* Skip any nameless bit fields.  */
6222       while (constructor_unfilled_fields != 0
6223              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6224              && DECL_NAME (constructor_unfilled_fields) == 0)
6225         constructor_unfilled_fields =
6226           TREE_CHAIN (constructor_unfilled_fields);
6227     }
6228   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6229     constructor_unfilled_fields = 0;
6230
6231   /* Now output any pending elements which have become next.  */
6232   if (pending)
6233     output_pending_init_elements (0);
6234 }
6235
6236 /* Output any pending elements which have become next.
6237    As we output elements, constructor_unfilled_{fields,index}
6238    advances, which may cause other elements to become next;
6239    if so, they too are output.
6240
6241    If ALL is 0, we return when there are
6242    no more pending elements to output now.
6243
6244    If ALL is 1, we output space as necessary so that
6245    we can output all the pending elements.  */
6246
6247 static void
6248 output_pending_init_elements (int all)
6249 {
6250   struct init_node *elt = constructor_pending_elts;
6251   tree next;
6252
6253  retry:
6254
6255   /* Look through the whole pending tree.
6256      If we find an element that should be output now,
6257      output it.  Otherwise, set NEXT to the element
6258      that comes first among those still pending.  */
6259
6260   next = 0;
6261   while (elt)
6262     {
6263       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6264         {
6265           if (tree_int_cst_equal (elt->purpose,
6266                                   constructor_unfilled_index))
6267             output_init_element (elt->value, true,
6268                                  TREE_TYPE (constructor_type),
6269                                  constructor_unfilled_index, 0);
6270           else if (tree_int_cst_lt (constructor_unfilled_index,
6271                                     elt->purpose))
6272             {
6273               /* Advance to the next smaller node.  */
6274               if (elt->left)
6275                 elt = elt->left;
6276               else
6277                 {
6278                   /* We have reached the smallest node bigger than the
6279                      current unfilled index.  Fill the space first.  */
6280                   next = elt->purpose;
6281                   break;
6282                 }
6283             }
6284           else
6285             {
6286               /* Advance to the next bigger node.  */
6287               if (elt->right)
6288                 elt = elt->right;
6289               else
6290                 {
6291                   /* We have reached the biggest node in a subtree.  Find
6292                      the parent of it, which is the next bigger node.  */
6293                   while (elt->parent && elt->parent->right == elt)
6294                     elt = elt->parent;
6295                   elt = elt->parent;
6296                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6297                                               elt->purpose))
6298                     {
6299                       next = elt->purpose;
6300                       break;
6301                     }
6302                 }
6303             }
6304         }
6305       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6306                || TREE_CODE (constructor_type) == UNION_TYPE)
6307         {
6308           tree ctor_unfilled_bitpos, elt_bitpos;
6309
6310           /* If the current record is complete we are done.  */
6311           if (constructor_unfilled_fields == 0)
6312             break;
6313
6314           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6315           elt_bitpos = bit_position (elt->purpose);
6316           /* We can't compare fields here because there might be empty
6317              fields in between.  */
6318           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6319             {
6320               constructor_unfilled_fields = elt->purpose;
6321               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6322                                    elt->purpose, 0);
6323             }
6324           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6325             {
6326               /* Advance to the next smaller node.  */
6327               if (elt->left)
6328                 elt = elt->left;
6329               else
6330                 {
6331                   /* We have reached the smallest node bigger than the
6332                      current unfilled field.  Fill the space first.  */
6333                   next = elt->purpose;
6334                   break;
6335                 }
6336             }
6337           else
6338             {
6339               /* Advance to the next bigger node.  */
6340               if (elt->right)
6341                 elt = elt->right;
6342               else
6343                 {
6344                   /* We have reached the biggest node in a subtree.  Find
6345                      the parent of it, which is the next bigger node.  */
6346                   while (elt->parent && elt->parent->right == elt)
6347                     elt = elt->parent;
6348                   elt = elt->parent;
6349                   if (elt
6350                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6351                                            bit_position (elt->purpose))))
6352                     {
6353                       next = elt->purpose;
6354                       break;
6355                     }
6356                 }
6357             }
6358         }
6359     }
6360
6361   /* Ordinarily return, but not if we want to output all
6362      and there are elements left.  */
6363   if (!(all && next != 0))
6364     return;
6365
6366   /* If it's not incremental, just skip over the gap, so that after
6367      jumping to retry we will output the next successive element.  */
6368   if (TREE_CODE (constructor_type) == RECORD_TYPE
6369       || TREE_CODE (constructor_type) == UNION_TYPE)
6370     constructor_unfilled_fields = next;
6371   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6372     constructor_unfilled_index = next;
6373
6374   /* ELT now points to the node in the pending tree with the next
6375      initializer to output.  */
6376   goto retry;
6377 }
6378 \f
6379 /* Add one non-braced element to the current constructor level.
6380    This adjusts the current position within the constructor's type.
6381    This may also start or terminate implicit levels
6382    to handle a partly-braced initializer.
6383
6384    Once this has found the correct level for the new element,
6385    it calls output_init_element.  */
6386
6387 void
6388 process_init_element (struct c_expr value)
6389 {
6390   tree orig_value = value.value;
6391   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6392   bool strict_string = value.original_code == STRING_CST;
6393
6394   designator_depth = 0;
6395   designator_erroneous = 0;
6396
6397   /* Handle superfluous braces around string cst as in
6398      char x[] = {"foo"}; */
6399   if (string_flag
6400       && constructor_type
6401       && TREE_CODE (constructor_type) == ARRAY_TYPE
6402       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6403       && integer_zerop (constructor_unfilled_index))
6404     {
6405       if (constructor_stack->replacement_value.value)
6406         error_init ("excess elements in char array initializer");
6407       constructor_stack->replacement_value = value;
6408       return;
6409     }
6410
6411   if (constructor_stack->replacement_value.value != 0)
6412     {
6413       error_init ("excess elements in struct initializer");
6414       return;
6415     }
6416
6417   /* Ignore elements of a brace group if it is entirely superfluous
6418      and has already been diagnosed.  */
6419   if (constructor_type == 0)
6420     return;
6421
6422   /* If we've exhausted any levels that didn't have braces,
6423      pop them now.  */
6424   while (constructor_stack->implicit)
6425     {
6426       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6427            || TREE_CODE (constructor_type) == UNION_TYPE)
6428           && constructor_fields == 0)
6429         process_init_element (pop_init_level (1));
6430       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6431                && (constructor_max_index == 0
6432                    || tree_int_cst_lt (constructor_max_index,
6433                                        constructor_index)))
6434         process_init_element (pop_init_level (1));
6435       else
6436         break;
6437     }
6438
6439   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6440   if (constructor_range_stack)
6441     {
6442       /* If value is a compound literal and we'll be just using its
6443          content, don't put it into a SAVE_EXPR.  */
6444       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6445           || !require_constant_value
6446           || flag_isoc99)
6447         value.value = save_expr (value.value);
6448     }
6449
6450   while (1)
6451     {
6452       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6453         {
6454           tree fieldtype;
6455           enum tree_code fieldcode;
6456
6457           if (constructor_fields == 0)
6458             {
6459               pedwarn_init ("excess elements in struct initializer");
6460               break;
6461             }
6462
6463           fieldtype = TREE_TYPE (constructor_fields);
6464           if (fieldtype != error_mark_node)
6465             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6466           fieldcode = TREE_CODE (fieldtype);
6467
6468           /* Error for non-static initialization of a flexible array member.  */
6469           if (fieldcode == ARRAY_TYPE
6470               && !require_constant_value
6471               && TYPE_SIZE (fieldtype) == NULL_TREE
6472               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6473             {
6474               error_init ("non-static initialization of a flexible array member");
6475               break;
6476             }
6477
6478           /* Accept a string constant to initialize a subarray.  */
6479           if (value.value != 0
6480               && fieldcode == ARRAY_TYPE
6481               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6482               && string_flag)
6483             value.value = orig_value;
6484           /* Otherwise, if we have come to a subaggregate,
6485              and we don't have an element of its type, push into it.  */
6486           else if (value.value != 0
6487                    && value.value != error_mark_node
6488                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6489                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6490                        || fieldcode == UNION_TYPE))
6491             {
6492               push_init_level (1);
6493               continue;
6494             }
6495
6496           if (value.value)
6497             {
6498               push_member_name (constructor_fields);
6499               output_init_element (value.value, strict_string,
6500                                    fieldtype, constructor_fields, 1);
6501               RESTORE_SPELLING_DEPTH (constructor_depth);
6502             }
6503           else
6504             /* Do the bookkeeping for an element that was
6505                directly output as a constructor.  */
6506             {
6507               /* For a record, keep track of end position of last field.  */
6508               if (DECL_SIZE (constructor_fields))
6509                 constructor_bit_index
6510                   = size_binop (PLUS_EXPR,
6511                                 bit_position (constructor_fields),
6512                                 DECL_SIZE (constructor_fields));
6513
6514               /* If the current field was the first one not yet written out,
6515                  it isn't now, so update.  */
6516               if (constructor_unfilled_fields == constructor_fields)
6517                 {
6518                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6519                   /* Skip any nameless bit fields.  */
6520                   while (constructor_unfilled_fields != 0
6521                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6522                          && DECL_NAME (constructor_unfilled_fields) == 0)
6523                     constructor_unfilled_fields =
6524                       TREE_CHAIN (constructor_unfilled_fields);
6525                 }
6526             }
6527
6528           constructor_fields = TREE_CHAIN (constructor_fields);
6529           /* Skip any nameless bit fields at the beginning.  */
6530           while (constructor_fields != 0
6531                  && DECL_C_BIT_FIELD (constructor_fields)
6532                  && DECL_NAME (constructor_fields) == 0)
6533             constructor_fields = TREE_CHAIN (constructor_fields);
6534         }
6535       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6536         {
6537           tree fieldtype;
6538           enum tree_code fieldcode;
6539
6540           if (constructor_fields == 0)
6541             {
6542               pedwarn_init ("excess elements in union initializer");
6543               break;
6544             }
6545
6546           fieldtype = TREE_TYPE (constructor_fields);
6547           if (fieldtype != error_mark_node)
6548             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6549           fieldcode = TREE_CODE (fieldtype);
6550
6551           /* Warn that traditional C rejects initialization of unions.
6552              We skip the warning if the value is zero.  This is done
6553              under the assumption that the zero initializer in user
6554              code appears conditioned on e.g. __STDC__ to avoid
6555              "missing initializer" warnings and relies on default
6556              initialization to zero in the traditional C case.
6557              We also skip the warning if the initializer is designated,
6558              again on the assumption that this must be conditional on
6559              __STDC__ anyway (and we've already complained about the
6560              member-designator already).  */
6561           if (!in_system_header && !constructor_designated
6562               && !(value.value && (integer_zerop (value.value)
6563                                    || real_zerop (value.value))))
6564             warning (OPT_Wtraditional, "traditional C rejects initialization "
6565                      "of unions");
6566
6567           /* Accept a string constant to initialize a subarray.  */
6568           if (value.value != 0
6569               && fieldcode == ARRAY_TYPE
6570               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6571               && string_flag)
6572             value.value = orig_value;
6573           /* Otherwise, if we have come to a subaggregate,
6574              and we don't have an element of its type, push into it.  */
6575           else if (value.value != 0
6576                    && value.value != error_mark_node
6577                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6578                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6579                        || fieldcode == UNION_TYPE))
6580             {
6581               push_init_level (1);
6582               continue;
6583             }
6584
6585           if (value.value)
6586             {
6587               push_member_name (constructor_fields);
6588               output_init_element (value.value, strict_string,
6589                                    fieldtype, constructor_fields, 1);
6590               RESTORE_SPELLING_DEPTH (constructor_depth);
6591             }
6592           else
6593             /* Do the bookkeeping for an element that was
6594                directly output as a constructor.  */
6595             {
6596               constructor_bit_index = DECL_SIZE (constructor_fields);
6597               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6598             }
6599
6600           constructor_fields = 0;
6601         }
6602       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6603         {
6604           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6605           enum tree_code eltcode = TREE_CODE (elttype);
6606
6607           /* Accept a string constant to initialize a subarray.  */
6608           if (value.value != 0
6609               && eltcode == ARRAY_TYPE
6610               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6611               && string_flag)
6612             value.value = orig_value;
6613           /* Otherwise, if we have come to a subaggregate,
6614              and we don't have an element of its type, push into it.  */
6615           else if (value.value != 0
6616                    && value.value != error_mark_node
6617                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6618                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6619                        || eltcode == UNION_TYPE))
6620             {
6621               push_init_level (1);
6622               continue;
6623             }
6624
6625           if (constructor_max_index != 0
6626               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6627                   || integer_all_onesp (constructor_max_index)))
6628             {
6629               pedwarn_init ("excess elements in array initializer");
6630               break;
6631             }
6632
6633           /* Now output the actual element.  */
6634           if (value.value)
6635             {
6636               push_array_bounds (tree_low_cst (constructor_index, 1));
6637               output_init_element (value.value, strict_string,
6638                                    elttype, constructor_index, 1);
6639               RESTORE_SPELLING_DEPTH (constructor_depth);
6640             }
6641
6642           constructor_index
6643             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6644
6645           if (!value.value)
6646             /* If we are doing the bookkeeping for an element that was
6647                directly output as a constructor, we must update
6648                constructor_unfilled_index.  */
6649             constructor_unfilled_index = constructor_index;
6650         }
6651       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6652         {
6653           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6654
6655          /* Do a basic check of initializer size.  Note that vectors
6656             always have a fixed size derived from their type.  */
6657           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6658             {
6659               pedwarn_init ("excess elements in vector initializer");
6660               break;
6661             }
6662
6663           /* Now output the actual element.  */
6664           if (value.value)
6665             output_init_element (value.value, strict_string,
6666                                  elttype, constructor_index, 1);
6667
6668           constructor_index
6669             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6670
6671           if (!value.value)
6672             /* If we are doing the bookkeeping for an element that was
6673                directly output as a constructor, we must update
6674                constructor_unfilled_index.  */
6675             constructor_unfilled_index = constructor_index;
6676         }
6677
6678       /* Handle the sole element allowed in a braced initializer
6679          for a scalar variable.  */
6680       else if (constructor_type != error_mark_node
6681                && constructor_fields == 0)
6682         {
6683           pedwarn_init ("excess elements in scalar initializer");
6684           break;
6685         }
6686       else
6687         {
6688           if (value.value)
6689             output_init_element (value.value, strict_string,
6690                                  constructor_type, NULL_TREE, 1);
6691           constructor_fields = 0;
6692         }
6693
6694       /* Handle range initializers either at this level or anywhere higher
6695          in the designator stack.  */
6696       if (constructor_range_stack)
6697         {
6698           struct constructor_range_stack *p, *range_stack;
6699           int finish = 0;
6700
6701           range_stack = constructor_range_stack;
6702           constructor_range_stack = 0;
6703           while (constructor_stack != range_stack->stack)
6704             {
6705               gcc_assert (constructor_stack->implicit);
6706               process_init_element (pop_init_level (1));
6707             }
6708           for (p = range_stack;
6709                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6710                p = p->prev)
6711             {
6712               gcc_assert (constructor_stack->implicit);
6713               process_init_element (pop_init_level (1));
6714             }
6715
6716           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6717           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6718             finish = 1;
6719
6720           while (1)
6721             {
6722               constructor_index = p->index;
6723               constructor_fields = p->fields;
6724               if (finish && p->range_end && p->index == p->range_start)
6725                 {
6726                   finish = 0;
6727                   p->prev = 0;
6728                 }
6729               p = p->next;
6730               if (!p)
6731                 break;
6732               push_init_level (2);
6733               p->stack = constructor_stack;
6734               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6735                 p->index = p->range_start;
6736             }
6737
6738           if (!finish)
6739             constructor_range_stack = range_stack;
6740           continue;
6741         }
6742
6743       break;
6744     }
6745
6746   constructor_range_stack = 0;
6747 }
6748 \f
6749 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6750    (guaranteed to be 'volatile' or null) and ARGS (represented using
6751    an ASM_EXPR node).  */
6752 tree
6753 build_asm_stmt (tree cv_qualifier, tree args)
6754 {
6755   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6756     ASM_VOLATILE_P (args) = 1;
6757   return add_stmt (args);
6758 }
6759
6760 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6761    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6762    SIMPLE indicates whether there was anything at all after the
6763    string in the asm expression -- asm("blah") and asm("blah" : )
6764    are subtly different.  We use a ASM_EXPR node to represent this.  */
6765 tree
6766 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6767                 bool simple)
6768 {
6769   tree tail;
6770   tree args;
6771   int i;
6772   const char *constraint;
6773   const char **oconstraints;
6774   bool allows_mem, allows_reg, is_inout;
6775   int ninputs, noutputs;
6776
6777   ninputs = list_length (inputs);
6778   noutputs = list_length (outputs);
6779   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6780
6781   string = resolve_asm_operand_names (string, outputs, inputs);
6782
6783   /* Remove output conversions that change the type but not the mode.  */
6784   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6785     {
6786       tree output = TREE_VALUE (tail);
6787
6788       /* ??? Really, this should not be here.  Users should be using a
6789          proper lvalue, dammit.  But there's a long history of using casts
6790          in the output operands.  In cases like longlong.h, this becomes a
6791          primitive form of typechecking -- if the cast can be removed, then
6792          the output operand had a type of the proper width; otherwise we'll
6793          get an error.  Gross, but ...  */
6794       STRIP_NOPS (output);
6795
6796       if (!lvalue_or_else (output, lv_asm))
6797         output = error_mark_node;
6798
6799       if (output != error_mark_node
6800           && (TREE_READONLY (output)
6801               || TYPE_READONLY (TREE_TYPE (output))
6802               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6803                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6804                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6805         readonly_error (output, lv_asm);
6806
6807       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6808       oconstraints[i] = constraint;
6809
6810       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6811                                    &allows_mem, &allows_reg, &is_inout))
6812         {
6813           /* If the operand is going to end up in memory,
6814              mark it addressable.  */
6815           if (!allows_reg && !c_mark_addressable (output))
6816             output = error_mark_node;
6817         }
6818       else
6819         output = error_mark_node;
6820
6821       TREE_VALUE (tail) = output;
6822     }
6823
6824   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6825     {
6826       tree input;
6827
6828       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6829       input = TREE_VALUE (tail);
6830
6831       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6832                                   oconstraints, &allows_mem, &allows_reg))
6833         {
6834           /* If the operand is going to end up in memory,
6835              mark it addressable.  */
6836           if (!allows_reg && allows_mem)
6837             {
6838               /* Strip the nops as we allow this case.  FIXME, this really
6839                  should be rejected or made deprecated.  */
6840               STRIP_NOPS (input);
6841               if (!c_mark_addressable (input))
6842                 input = error_mark_node;
6843           }
6844         }
6845       else
6846         input = error_mark_node;
6847
6848       TREE_VALUE (tail) = input;
6849     }
6850
6851   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6852
6853   /* asm statements without outputs, including simple ones, are treated
6854      as volatile.  */
6855   ASM_INPUT_P (args) = simple;
6856   ASM_VOLATILE_P (args) = (noutputs == 0);
6857
6858   return args;
6859 }
6860 \f
6861 /* Generate a goto statement to LABEL.  */
6862
6863 tree
6864 c_finish_goto_label (tree label)
6865 {
6866   tree decl = lookup_label (label);
6867   if (!decl)
6868     return NULL_TREE;
6869
6870   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6871     {
6872       error ("jump into statement expression");
6873       return NULL_TREE;
6874     }
6875
6876   if (C_DECL_UNJUMPABLE_VM (decl))
6877     {
6878       error ("jump into scope of identifier with variably modified type");
6879       return NULL_TREE;
6880     }
6881
6882   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6883     {
6884       /* No jump from outside this statement expression context, so
6885          record that there is a jump from within this context.  */
6886       struct c_label_list *nlist;
6887       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6888       nlist->next = label_context_stack_se->labels_used;
6889       nlist->label = decl;
6890       label_context_stack_se->labels_used = nlist;
6891     }
6892
6893   if (!C_DECL_UNDEFINABLE_VM (decl))
6894     {
6895       /* No jump from outside this context context of identifiers with
6896          variably modified type, so record that there is a jump from
6897          within this context.  */
6898       struct c_label_list *nlist;
6899       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6900       nlist->next = label_context_stack_vm->labels_used;
6901       nlist->label = decl;
6902       label_context_stack_vm->labels_used = nlist;
6903     }
6904
6905   TREE_USED (decl) = 1;
6906   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6907 }
6908
6909 /* Generate a computed goto statement to EXPR.  */
6910
6911 tree
6912 c_finish_goto_ptr (tree expr)
6913 {
6914   if (pedantic)
6915     pedwarn ("ISO C forbids %<goto *expr;%>");
6916   expr = convert (ptr_type_node, expr);
6917   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6918 }
6919
6920 /* Generate a C `return' statement.  RETVAL is the expression for what
6921    to return, or a null pointer for `return;' with no value.  */
6922
6923 tree
6924 c_finish_return (tree retval)
6925 {
6926   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6927   bool no_warning = false;
6928
6929   if (TREE_THIS_VOLATILE (current_function_decl))
6930     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6931
6932   if (!retval)
6933     {
6934       current_function_returns_null = 1;
6935       if ((warn_return_type || flag_isoc99)
6936           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6937         {
6938           pedwarn_c99 ("%<return%> with no value, in "
6939                        "function returning non-void");
6940           no_warning = true;
6941         }
6942     }
6943   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6944     {
6945       current_function_returns_null = 1;
6946       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6947         pedwarn ("%<return%> with a value, in function returning void");
6948       else if (pedantic)
6949         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
6950     }
6951   else
6952     {
6953       tree t = convert_for_assignment (valtype, retval, ic_return,
6954                                        NULL_TREE, NULL_TREE, 0);
6955       tree res = DECL_RESULT (current_function_decl);
6956       tree inner;
6957
6958       current_function_returns_value = 1;
6959       if (t == error_mark_node)
6960         return NULL_TREE;
6961
6962       inner = t = convert (TREE_TYPE (res), t);
6963
6964       /* Strip any conversions, additions, and subtractions, and see if
6965          we are returning the address of a local variable.  Warn if so.  */
6966       while (1)
6967         {
6968           switch (TREE_CODE (inner))
6969             {
6970             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6971             case PLUS_EXPR:
6972               inner = TREE_OPERAND (inner, 0);
6973               continue;
6974
6975             case MINUS_EXPR:
6976               /* If the second operand of the MINUS_EXPR has a pointer
6977                  type (or is converted from it), this may be valid, so
6978                  don't give a warning.  */
6979               {
6980                 tree op1 = TREE_OPERAND (inner, 1);
6981
6982                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6983                        && (TREE_CODE (op1) == NOP_EXPR
6984                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6985                            || TREE_CODE (op1) == CONVERT_EXPR))
6986                   op1 = TREE_OPERAND (op1, 0);
6987
6988                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6989                   break;
6990
6991                 inner = TREE_OPERAND (inner, 0);
6992                 continue;
6993               }
6994
6995             case ADDR_EXPR:
6996               inner = TREE_OPERAND (inner, 0);
6997
6998               while (REFERENCE_CLASS_P (inner)
6999                      && TREE_CODE (inner) != INDIRECT_REF)
7000                 inner = TREE_OPERAND (inner, 0);
7001
7002               if (DECL_P (inner)
7003                   && !DECL_EXTERNAL (inner)
7004                   && !TREE_STATIC (inner)
7005                   && DECL_CONTEXT (inner) == current_function_decl)
7006                 warning (0, "function returns address of local variable");
7007               break;
7008
7009             default:
7010               break;
7011             }
7012
7013           break;
7014         }
7015
7016       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7017     }
7018
7019   ret_stmt = build_stmt (RETURN_EXPR, retval);
7020   TREE_NO_WARNING (ret_stmt) |= no_warning;
7021   return add_stmt (ret_stmt);
7022 }
7023 \f
7024 struct c_switch {
7025   /* The SWITCH_EXPR being built.  */
7026   tree switch_expr;
7027
7028   /* The original type of the testing expression, i.e. before the
7029      default conversion is applied.  */
7030   tree orig_type;
7031
7032   /* A splay-tree mapping the low element of a case range to the high
7033      element, or NULL_TREE if there is no high element.  Used to
7034      determine whether or not a new case label duplicates an old case
7035      label.  We need a tree, rather than simply a hash table, because
7036      of the GNU case range extension.  */
7037   splay_tree cases;
7038
7039   /* Number of nested statement expressions within this switch
7040      statement; if nonzero, case and default labels may not
7041      appear.  */
7042   unsigned int blocked_stmt_expr;
7043
7044   /* Scope of outermost declarations of identifiers with variably
7045      modified type within this switch statement; if nonzero, case and
7046      default labels may not appear.  */
7047   unsigned int blocked_vm;
7048
7049   /* The next node on the stack.  */
7050   struct c_switch *next;
7051 };
7052
7053 /* A stack of the currently active switch statements.  The innermost
7054    switch statement is on the top of the stack.  There is no need to
7055    mark the stack for garbage collection because it is only active
7056    during the processing of the body of a function, and we never
7057    collect at that point.  */
7058
7059 struct c_switch *c_switch_stack;
7060
7061 /* Start a C switch statement, testing expression EXP.  Return the new
7062    SWITCH_EXPR.  */
7063
7064 tree
7065 c_start_case (tree exp)
7066 {
7067   tree orig_type = error_mark_node;
7068   struct c_switch *cs;
7069
7070   if (exp != error_mark_node)
7071     {
7072       orig_type = TREE_TYPE (exp);
7073
7074       if (!INTEGRAL_TYPE_P (orig_type))
7075         {
7076           if (orig_type != error_mark_node)
7077             {
7078               error ("switch quantity not an integer");
7079               orig_type = error_mark_node;
7080             }
7081           exp = integer_zero_node;
7082         }
7083       else
7084         {
7085           tree type = TYPE_MAIN_VARIANT (orig_type);
7086
7087           if (!in_system_header
7088               && (type == long_integer_type_node
7089                   || type == long_unsigned_type_node))
7090             warning (OPT_Wtraditional, "%<long%> switch expression not "
7091                      "converted to %<int%> in ISO C");
7092
7093           exp = default_conversion (exp);
7094         }
7095     }
7096
7097   /* Add this new SWITCH_EXPR to the stack.  */
7098   cs = XNEW (struct c_switch);
7099   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7100   cs->orig_type = orig_type;
7101   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7102   cs->blocked_stmt_expr = 0;
7103   cs->blocked_vm = 0;
7104   cs->next = c_switch_stack;
7105   c_switch_stack = cs;
7106
7107   return add_stmt (cs->switch_expr);
7108 }
7109
7110 /* Process a case label.  */
7111
7112 tree
7113 do_case (tree low_value, tree high_value)
7114 {
7115   tree label = NULL_TREE;
7116
7117   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7118       && !c_switch_stack->blocked_vm)
7119     {
7120       label = c_add_case_label (c_switch_stack->cases,
7121                                 SWITCH_COND (c_switch_stack->switch_expr),
7122                                 c_switch_stack->orig_type,
7123                                 low_value, high_value);
7124       if (label == error_mark_node)
7125         label = NULL_TREE;
7126     }
7127   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7128     {
7129       if (low_value)
7130         error ("case label in statement expression not containing "
7131                "enclosing switch statement");
7132       else
7133         error ("%<default%> label in statement expression not containing "
7134                "enclosing switch statement");
7135     }
7136   else if (c_switch_stack && c_switch_stack->blocked_vm)
7137     {
7138       if (low_value)
7139         error ("case label in scope of identifier with variably modified "
7140                "type not containing enclosing switch statement");
7141       else
7142         error ("%<default%> label in scope of identifier with variably "
7143                "modified type not containing enclosing switch statement");
7144     }
7145   else if (low_value)
7146     error ("case label not within a switch statement");
7147   else
7148     error ("%<default%> label not within a switch statement");
7149
7150   return label;
7151 }
7152
7153 /* Finish the switch statement.  */
7154
7155 void
7156 c_finish_case (tree body)
7157 {
7158   struct c_switch *cs = c_switch_stack;
7159   location_t switch_location;
7160
7161   SWITCH_BODY (cs->switch_expr) = body;
7162
7163   /* We must not be within a statement expression nested in the switch
7164      at this point; we might, however, be within the scope of an
7165      identifier with variably modified type nested in the switch.  */
7166   gcc_assert (!cs->blocked_stmt_expr);
7167
7168   /* Emit warnings as needed.  */
7169   if (EXPR_HAS_LOCATION (cs->switch_expr))
7170     switch_location = EXPR_LOCATION (cs->switch_expr);
7171   else
7172     switch_location = input_location;
7173   c_do_switch_warnings (cs->cases, switch_location,
7174                         TREE_TYPE (cs->switch_expr),
7175                         SWITCH_COND (cs->switch_expr));
7176
7177   /* Pop the stack.  */
7178   c_switch_stack = cs->next;
7179   splay_tree_delete (cs->cases);
7180   XDELETE (cs);
7181 }
7182 \f
7183 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7184    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7185    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7186    statement, and was not surrounded with parenthesis.  */
7187
7188 void
7189 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7190                   tree else_block, bool nested_if)
7191 {
7192   tree stmt;
7193
7194   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7195   if (warn_parentheses && nested_if && else_block == NULL)
7196     {
7197       tree inner_if = then_block;
7198
7199       /* We know from the grammar productions that there is an IF nested
7200          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7201          it might not be exactly THEN_BLOCK, but should be the last
7202          non-container statement within.  */
7203       while (1)
7204         switch (TREE_CODE (inner_if))
7205           {
7206           case COND_EXPR:
7207             goto found;
7208           case BIND_EXPR:
7209             inner_if = BIND_EXPR_BODY (inner_if);
7210             break;
7211           case STATEMENT_LIST:
7212             inner_if = expr_last (then_block);
7213             break;
7214           case TRY_FINALLY_EXPR:
7215           case TRY_CATCH_EXPR:
7216             inner_if = TREE_OPERAND (inner_if, 0);
7217             break;
7218           default:
7219             gcc_unreachable ();
7220           }
7221     found:
7222
7223       if (COND_EXPR_ELSE (inner_if))
7224          warning (OPT_Wparentheses,
7225                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7226                   &if_locus);
7227     }
7228
7229   empty_body_warning (then_block, else_block);
7230
7231   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7232   SET_EXPR_LOCATION (stmt, if_locus);
7233   add_stmt (stmt);
7234 }
7235
7236 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7237    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7238    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7239    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7240    the continue label.  Everything is allowed to be NULL.  */
7241
7242 void
7243 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7244                tree blab, tree clab, bool cond_is_first)
7245 {
7246   tree entry = NULL, exit = NULL, t;
7247
7248   /* If the condition is zero don't generate a loop construct.  */
7249   if (cond && integer_zerop (cond))
7250     {
7251       if (cond_is_first)
7252         {
7253           t = build_and_jump (&blab);
7254           SET_EXPR_LOCATION (t, start_locus);
7255           add_stmt (t);
7256         }
7257     }
7258   else
7259     {
7260       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7261
7262       /* If we have an exit condition, then we build an IF with gotos either
7263          out of the loop, or to the top of it.  If there's no exit condition,
7264          then we just build a jump back to the top.  */
7265       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7266
7267       if (cond && !integer_nonzerop (cond))
7268         {
7269           /* Canonicalize the loop condition to the end.  This means
7270              generating a branch to the loop condition.  Reuse the
7271              continue label, if possible.  */
7272           if (cond_is_first)
7273             {
7274               if (incr || !clab)
7275                 {
7276                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7277                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7278                 }
7279               else
7280                 t = build1 (GOTO_EXPR, void_type_node, clab);
7281               SET_EXPR_LOCATION (t, start_locus);
7282               add_stmt (t);
7283             }
7284
7285           t = build_and_jump (&blab);
7286           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7287           if (cond_is_first)
7288             SET_EXPR_LOCATION (exit, start_locus);
7289           else
7290             SET_EXPR_LOCATION (exit, input_location);
7291         }
7292
7293       add_stmt (top);
7294     }
7295
7296   if (body)
7297     add_stmt (body);
7298   if (clab)
7299     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7300   if (incr)
7301     add_stmt (incr);
7302   if (entry)
7303     add_stmt (entry);
7304   if (exit)
7305     add_stmt (exit);
7306   if (blab)
7307     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7308 }
7309
7310 tree
7311 c_finish_bc_stmt (tree *label_p, bool is_break)
7312 {
7313   bool skip;
7314   tree label = *label_p;
7315
7316   /* In switch statements break is sometimes stylistically used after
7317      a return statement.  This can lead to spurious warnings about
7318      control reaching the end of a non-void function when it is
7319      inlined.  Note that we are calling block_may_fallthru with
7320      language specific tree nodes; this works because
7321      block_may_fallthru returns true when given something it does not
7322      understand.  */
7323   skip = !block_may_fallthru (cur_stmt_list);
7324
7325   if (!label)
7326     {
7327       if (!skip)
7328         *label_p = label = create_artificial_label ();
7329     }
7330   else if (TREE_CODE (label) == LABEL_DECL)
7331     ;
7332   else switch (TREE_INT_CST_LOW (label))
7333     {
7334     case 0:
7335       if (is_break)
7336         error ("break statement not within loop or switch");
7337       else
7338         error ("continue statement not within a loop");
7339       return NULL_TREE;
7340
7341     case 1:
7342       gcc_assert (is_break);
7343       error ("break statement used with OpenMP for loop");
7344       return NULL_TREE;
7345
7346     default:
7347       gcc_unreachable ();
7348     }
7349
7350   if (skip)
7351     return NULL_TREE;
7352
7353   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7354 }
7355
7356 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7357
7358 static void
7359 emit_side_effect_warnings (tree expr)
7360 {
7361   if (expr == error_mark_node)
7362     ;
7363   else if (!TREE_SIDE_EFFECTS (expr))
7364     {
7365       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7366         warning (OPT_Wunused_value, "%Hstatement with no effect",
7367                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7368     }
7369   else
7370     warn_if_unused_value (expr, input_location);
7371 }
7372
7373 /* Process an expression as if it were a complete statement.  Emit
7374    diagnostics, but do not call ADD_STMT.  */
7375
7376 tree
7377 c_process_expr_stmt (tree expr)
7378 {
7379   if (!expr)
7380     return NULL_TREE;
7381
7382   if (warn_sequence_point)
7383     verify_sequence_points (expr);
7384
7385   if (TREE_TYPE (expr) != error_mark_node
7386       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7387       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7388     error ("expression statement has incomplete type");
7389
7390   /* If we're not processing a statement expression, warn about unused values.
7391      Warnings for statement expressions will be emitted later, once we figure
7392      out which is the result.  */
7393   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7394       && warn_unused_value)
7395     emit_side_effect_warnings (expr);
7396
7397   /* If the expression is not of a type to which we cannot assign a line
7398      number, wrap the thing in a no-op NOP_EXPR.  */
7399   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7400     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7401
7402   if (CAN_HAVE_LOCATION_P (expr))
7403     SET_EXPR_LOCATION (expr, input_location);
7404
7405   return expr;
7406 }
7407
7408 /* Emit an expression as a statement.  */
7409
7410 tree
7411 c_finish_expr_stmt (tree expr)
7412 {
7413   if (expr)
7414     return add_stmt (c_process_expr_stmt (expr));
7415   else
7416     return NULL;
7417 }
7418
7419 /* Do the opposite and emit a statement as an expression.  To begin,
7420    create a new binding level and return it.  */
7421
7422 tree
7423 c_begin_stmt_expr (void)
7424 {
7425   tree ret;
7426   struct c_label_context_se *nstack;
7427   struct c_label_list *glist;
7428
7429   /* We must force a BLOCK for this level so that, if it is not expanded
7430      later, there is a way to turn off the entire subtree of blocks that
7431      are contained in it.  */
7432   keep_next_level ();
7433   ret = c_begin_compound_stmt (true);
7434   if (c_switch_stack)
7435     {
7436       c_switch_stack->blocked_stmt_expr++;
7437       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7438     }
7439   for (glist = label_context_stack_se->labels_used;
7440        glist != NULL;
7441        glist = glist->next)
7442     {
7443       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7444     }
7445   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7446   nstack->labels_def = NULL;
7447   nstack->labels_used = NULL;
7448   nstack->next = label_context_stack_se;
7449   label_context_stack_se = nstack;
7450
7451   /* Mark the current statement list as belonging to a statement list.  */
7452   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7453
7454   return ret;
7455 }
7456
7457 tree
7458 c_finish_stmt_expr (tree body)
7459 {
7460   tree last, type, tmp, val;
7461   tree *last_p;
7462   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7463
7464   body = c_end_compound_stmt (body, true);
7465   if (c_switch_stack)
7466     {
7467       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7468       c_switch_stack->blocked_stmt_expr--;
7469     }
7470   /* It is no longer possible to jump to labels defined within this
7471      statement expression.  */
7472   for (dlist = label_context_stack_se->labels_def;
7473        dlist != NULL;
7474        dlist = dlist->next)
7475     {
7476       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7477     }
7478   /* It is again possible to define labels with a goto just outside
7479      this statement expression.  */
7480   for (glist = label_context_stack_se->next->labels_used;
7481        glist != NULL;
7482        glist = glist->next)
7483     {
7484       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7485       glist_prev = glist;
7486     }
7487   if (glist_prev != NULL)
7488     glist_prev->next = label_context_stack_se->labels_used;
7489   else
7490     label_context_stack_se->next->labels_used
7491       = label_context_stack_se->labels_used;
7492   label_context_stack_se = label_context_stack_se->next;
7493
7494   /* Locate the last statement in BODY.  See c_end_compound_stmt
7495      about always returning a BIND_EXPR.  */
7496   last_p = &BIND_EXPR_BODY (body);
7497   last = BIND_EXPR_BODY (body);
7498
7499  continue_searching:
7500   if (TREE_CODE (last) == STATEMENT_LIST)
7501     {
7502       tree_stmt_iterator i;
7503
7504       /* This can happen with degenerate cases like ({ }).  No value.  */
7505       if (!TREE_SIDE_EFFECTS (last))
7506         return body;
7507
7508       /* If we're supposed to generate side effects warnings, process
7509          all of the statements except the last.  */
7510       if (warn_unused_value)
7511         {
7512           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7513             emit_side_effect_warnings (tsi_stmt (i));
7514         }
7515       else
7516         i = tsi_last (last);
7517       last_p = tsi_stmt_ptr (i);
7518       last = *last_p;
7519     }
7520
7521   /* If the end of the list is exception related, then the list was split
7522      by a call to push_cleanup.  Continue searching.  */
7523   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7524       || TREE_CODE (last) == TRY_CATCH_EXPR)
7525     {
7526       last_p = &TREE_OPERAND (last, 0);
7527       last = *last_p;
7528       goto continue_searching;
7529     }
7530
7531   /* In the case that the BIND_EXPR is not necessary, return the
7532      expression out from inside it.  */
7533   if (last == error_mark_node
7534       || (last == BIND_EXPR_BODY (body)
7535           && BIND_EXPR_VARS (body) == NULL))
7536     {
7537       /* Do not warn if the return value of a statement expression is
7538          unused.  */
7539       if (CAN_HAVE_LOCATION_P (last))
7540         TREE_NO_WARNING (last) = 1;
7541       return last;
7542     }
7543
7544   /* Extract the type of said expression.  */
7545   type = TREE_TYPE (last);
7546
7547   /* If we're not returning a value at all, then the BIND_EXPR that
7548      we already have is a fine expression to return.  */
7549   if (!type || VOID_TYPE_P (type))
7550     return body;
7551
7552   /* Now that we've located the expression containing the value, it seems
7553      silly to make voidify_wrapper_expr repeat the process.  Create a
7554      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7555   tmp = create_tmp_var_raw (type, NULL);
7556
7557   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7558      tree_expr_nonnegative_p giving up immediately.  */
7559   val = last;
7560   if (TREE_CODE (val) == NOP_EXPR
7561       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7562     val = TREE_OPERAND (val, 0);
7563
7564   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7565   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7566
7567   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7568 }
7569
7570 /* Begin the scope of an identifier of variably modified type, scope
7571    number SCOPE.  Jumping from outside this scope to inside it is not
7572    permitted.  */
7573
7574 void
7575 c_begin_vm_scope (unsigned int scope)
7576 {
7577   struct c_label_context_vm *nstack;
7578   struct c_label_list *glist;
7579
7580   gcc_assert (scope > 0);
7581
7582   /* At file_scope, we don't have to do any processing.  */
7583   if (label_context_stack_vm == NULL)
7584     return;
7585
7586   if (c_switch_stack && !c_switch_stack->blocked_vm)
7587     c_switch_stack->blocked_vm = scope;
7588   for (glist = label_context_stack_vm->labels_used;
7589        glist != NULL;
7590        glist = glist->next)
7591     {
7592       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7593     }
7594   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7595   nstack->labels_def = NULL;
7596   nstack->labels_used = NULL;
7597   nstack->scope = scope;
7598   nstack->next = label_context_stack_vm;
7599   label_context_stack_vm = nstack;
7600 }
7601
7602 /* End a scope which may contain identifiers of variably modified
7603    type, scope number SCOPE.  */
7604
7605 void
7606 c_end_vm_scope (unsigned int scope)
7607 {
7608   if (label_context_stack_vm == NULL)
7609     return;
7610   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7611     c_switch_stack->blocked_vm = 0;
7612   /* We may have a number of nested scopes of identifiers with
7613      variably modified type, all at this depth.  Pop each in turn.  */
7614   while (label_context_stack_vm->scope == scope)
7615     {
7616       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7617
7618       /* It is no longer possible to jump to labels defined within this
7619          scope.  */
7620       for (dlist = label_context_stack_vm->labels_def;
7621            dlist != NULL;
7622            dlist = dlist->next)
7623         {
7624           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7625         }
7626       /* It is again possible to define labels with a goto just outside
7627          this scope.  */
7628       for (glist = label_context_stack_vm->next->labels_used;
7629            glist != NULL;
7630            glist = glist->next)
7631         {
7632           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7633           glist_prev = glist;
7634         }
7635       if (glist_prev != NULL)
7636         glist_prev->next = label_context_stack_vm->labels_used;
7637       else
7638         label_context_stack_vm->next->labels_used
7639           = label_context_stack_vm->labels_used;
7640       label_context_stack_vm = label_context_stack_vm->next;
7641     }
7642 }
7643 \f
7644 /* Begin and end compound statements.  This is as simple as pushing
7645    and popping new statement lists from the tree.  */
7646
7647 tree
7648 c_begin_compound_stmt (bool do_scope)
7649 {
7650   tree stmt = push_stmt_list ();
7651   if (do_scope)
7652     push_scope ();
7653   return stmt;
7654 }
7655
7656 tree
7657 c_end_compound_stmt (tree stmt, bool do_scope)
7658 {
7659   tree block = NULL;
7660
7661   if (do_scope)
7662     {
7663       if (c_dialect_objc ())
7664         objc_clear_super_receiver ();
7665       block = pop_scope ();
7666     }
7667
7668   stmt = pop_stmt_list (stmt);
7669   stmt = c_build_bind_expr (block, stmt);
7670
7671   /* If this compound statement is nested immediately inside a statement
7672      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7673      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7674      STATEMENT_LISTs merge, and thus we can lose track of what statement
7675      was really last.  */
7676   if (cur_stmt_list
7677       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7678       && TREE_CODE (stmt) != BIND_EXPR)
7679     {
7680       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7681       TREE_SIDE_EFFECTS (stmt) = 1;
7682     }
7683
7684   return stmt;
7685 }
7686
7687 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7688    when the current scope is exited.  EH_ONLY is true when this is not
7689    meant to apply to normal control flow transfer.  */
7690
7691 void
7692 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7693 {
7694   enum tree_code code;
7695   tree stmt, list;
7696   bool stmt_expr;
7697
7698   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7699   stmt = build_stmt (code, NULL, cleanup);
7700   add_stmt (stmt);
7701   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7702   list = push_stmt_list ();
7703   TREE_OPERAND (stmt, 0) = list;
7704   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7705 }
7706 \f
7707 /* Build a binary-operation expression without default conversions.
7708    CODE is the kind of expression to build.
7709    This function differs from `build' in several ways:
7710    the data type of the result is computed and recorded in it,
7711    warnings are generated if arg data types are invalid,
7712    special handling for addition and subtraction of pointers is known,
7713    and some optimization is done (operations on narrow ints
7714    are done in the narrower type when that gives the same result).
7715    Constant folding is also done before the result is returned.
7716
7717    Note that the operands will never have enumeral types, or function
7718    or array types, because either they will have the default conversions
7719    performed or they have both just been converted to some other type in which
7720    the arithmetic is to be done.  */
7721
7722 tree
7723 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7724                  int convert_p)
7725 {
7726   tree type0, type1;
7727   enum tree_code code0, code1;
7728   tree op0, op1;
7729   const char *invalid_op_diag;
7730
7731   /* Expression code to give to the expression when it is built.
7732      Normally this is CODE, which is what the caller asked for,
7733      but in some special cases we change it.  */
7734   enum tree_code resultcode = code;
7735
7736   /* Data type in which the computation is to be performed.
7737      In the simplest cases this is the common type of the arguments.  */
7738   tree result_type = NULL;
7739
7740   /* Nonzero means operands have already been type-converted
7741      in whatever way is necessary.
7742      Zero means they need to be converted to RESULT_TYPE.  */
7743   int converted = 0;
7744
7745   /* Nonzero means create the expression with this type, rather than
7746      RESULT_TYPE.  */
7747   tree build_type = 0;
7748
7749   /* Nonzero means after finally constructing the expression
7750      convert it to this type.  */
7751   tree final_type = 0;
7752
7753   /* Nonzero if this is an operation like MIN or MAX which can
7754      safely be computed in short if both args are promoted shorts.
7755      Also implies COMMON.
7756      -1 indicates a bitwise operation; this makes a difference
7757      in the exact conditions for when it is safe to do the operation
7758      in a narrower mode.  */
7759   int shorten = 0;
7760
7761   /* Nonzero if this is a comparison operation;
7762      if both args are promoted shorts, compare the original shorts.
7763      Also implies COMMON.  */
7764   int short_compare = 0;
7765
7766   /* Nonzero if this is a right-shift operation, which can be computed on the
7767      original short and then promoted if the operand is a promoted short.  */
7768   int short_shift = 0;
7769
7770   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7771   int common = 0;
7772
7773   /* True means types are compatible as far as ObjC is concerned.  */
7774   bool objc_ok;
7775
7776   if (convert_p)
7777     {
7778       op0 = default_conversion (orig_op0);
7779       op1 = default_conversion (orig_op1);
7780     }
7781   else
7782     {
7783       op0 = orig_op0;
7784       op1 = orig_op1;
7785     }
7786
7787   type0 = TREE_TYPE (op0);
7788   type1 = TREE_TYPE (op1);
7789
7790   /* The expression codes of the data types of the arguments tell us
7791      whether the arguments are integers, floating, pointers, etc.  */
7792   code0 = TREE_CODE (type0);
7793   code1 = TREE_CODE (type1);
7794
7795   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7796   STRIP_TYPE_NOPS (op0);
7797   STRIP_TYPE_NOPS (op1);
7798
7799   /* If an error was already reported for one of the arguments,
7800      avoid reporting another error.  */
7801
7802   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7803     return error_mark_node;
7804
7805   if ((invalid_op_diag
7806        = targetm.invalid_binary_op (code, type0, type1)))
7807     {
7808       error (invalid_op_diag);
7809       return error_mark_node;
7810     }
7811
7812   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7813
7814   switch (code)
7815     {
7816     case PLUS_EXPR:
7817       /* Handle the pointer + int case.  */
7818       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7819         return pointer_int_sum (PLUS_EXPR, op0, op1);
7820       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7821         return pointer_int_sum (PLUS_EXPR, op1, op0);
7822       else
7823         common = 1;
7824       break;
7825
7826     case MINUS_EXPR:
7827       /* Subtraction of two similar pointers.
7828          We must subtract them as integers, then divide by object size.  */
7829       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7830           && comp_target_types (type0, type1))
7831         return pointer_diff (op0, op1);
7832       /* Handle pointer minus int.  Just like pointer plus int.  */
7833       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7834         return pointer_int_sum (MINUS_EXPR, op0, op1);
7835       else
7836         common = 1;
7837       break;
7838
7839     case MULT_EXPR:
7840       common = 1;
7841       break;
7842
7843     case TRUNC_DIV_EXPR:
7844     case CEIL_DIV_EXPR:
7845     case FLOOR_DIV_EXPR:
7846     case ROUND_DIV_EXPR:
7847     case EXACT_DIV_EXPR:
7848       /* Floating point division by zero is a legitimate way to obtain
7849          infinities and NaNs.  */
7850       if (skip_evaluation == 0 && integer_zerop (op1))
7851         warning (OPT_Wdiv_by_zero, "division by zero");
7852
7853       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7854            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7855           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7856               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7857         {
7858           enum tree_code tcode0 = code0, tcode1 = code1;
7859
7860           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7861             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7862           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7863             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7864
7865           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7866             resultcode = RDIV_EXPR;
7867           else
7868             /* Although it would be tempting to shorten always here, that
7869                loses on some targets, since the modulo instruction is
7870                undefined if the quotient can't be represented in the
7871                computation mode.  We shorten only if unsigned or if
7872                dividing by something we know != -1.  */
7873             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7874                        || (TREE_CODE (op1) == INTEGER_CST
7875                            && !integer_all_onesp (op1)));
7876           common = 1;
7877         }
7878       break;
7879
7880     case BIT_AND_EXPR:
7881     case BIT_IOR_EXPR:
7882     case BIT_XOR_EXPR:
7883       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7884         shorten = -1;
7885       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7886         common = 1;
7887       break;
7888
7889     case TRUNC_MOD_EXPR:
7890     case FLOOR_MOD_EXPR:
7891       if (skip_evaluation == 0 && integer_zerop (op1))
7892         warning (OPT_Wdiv_by_zero, "division by zero");
7893
7894       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7895         {
7896           /* Although it would be tempting to shorten always here, that loses
7897              on some targets, since the modulo instruction is undefined if the
7898              quotient can't be represented in the computation mode.  We shorten
7899              only if unsigned or if dividing by something we know != -1.  */
7900           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7901                      || (TREE_CODE (op1) == INTEGER_CST
7902                          && !integer_all_onesp (op1)));
7903           common = 1;
7904         }
7905       break;
7906
7907     case TRUTH_ANDIF_EXPR:
7908     case TRUTH_ORIF_EXPR:
7909     case TRUTH_AND_EXPR:
7910     case TRUTH_OR_EXPR:
7911     case TRUTH_XOR_EXPR:
7912       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7913            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7914           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7915               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7916         {
7917           /* Result of these operations is always an int,
7918              but that does not mean the operands should be
7919              converted to ints!  */
7920           result_type = integer_type_node;
7921           op0 = c_common_truthvalue_conversion (op0);
7922           op1 = c_common_truthvalue_conversion (op1);
7923           converted = 1;
7924         }
7925       break;
7926
7927       /* Shift operations: result has same type as first operand;
7928          always convert second operand to int.
7929          Also set SHORT_SHIFT if shifting rightward.  */
7930
7931     case RSHIFT_EXPR:
7932       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7933         {
7934           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7935             {
7936               if (tree_int_cst_sgn (op1) < 0)
7937                 warning (0, "right shift count is negative");
7938               else
7939                 {
7940                   if (!integer_zerop (op1))
7941                     short_shift = 1;
7942
7943                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7944                     warning (0, "right shift count >= width of type");
7945                 }
7946             }
7947
7948           /* Use the type of the value to be shifted.  */
7949           result_type = type0;
7950           /* Convert the shift-count to an integer, regardless of size
7951              of value being shifted.  */
7952           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7953             op1 = convert (integer_type_node, op1);
7954           /* Avoid converting op1 to result_type later.  */
7955           converted = 1;
7956         }
7957       break;
7958
7959     case LSHIFT_EXPR:
7960       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7961         {
7962           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7963             {
7964               if (tree_int_cst_sgn (op1) < 0)
7965                 warning (0, "left shift count is negative");
7966
7967               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7968                 warning (0, "left shift count >= width of type");
7969             }
7970
7971           /* Use the type of the value to be shifted.  */
7972           result_type = type0;
7973           /* Convert the shift-count to an integer, regardless of size
7974              of value being shifted.  */
7975           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7976             op1 = convert (integer_type_node, op1);
7977           /* Avoid converting op1 to result_type later.  */
7978           converted = 1;
7979         }
7980       break;
7981
7982     case EQ_EXPR:
7983     case NE_EXPR:
7984       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7985         warning (OPT_Wfloat_equal,
7986                  "comparing floating point with == or != is unsafe");
7987       /* Result of comparison is always int,
7988          but don't convert the args to int!  */
7989       build_type = integer_type_node;
7990       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7991            || code0 == COMPLEX_TYPE)
7992           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7993               || code1 == COMPLEX_TYPE))
7994         short_compare = 1;
7995       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7996         {
7997           tree tt0 = TREE_TYPE (type0);
7998           tree tt1 = TREE_TYPE (type1);
7999           /* Anything compares with void *.  void * compares with anything.
8000              Otherwise, the targets must be compatible
8001              and both must be object or both incomplete.  */
8002           if (comp_target_types (type0, type1))
8003             result_type = common_pointer_type (type0, type1);
8004           else if (VOID_TYPE_P (tt0))
8005             {
8006               /* op0 != orig_op0 detects the case of something
8007                  whose value is 0 but which isn't a valid null ptr const.  */
8008               if (pedantic && !null_pointer_constant_p (orig_op0)
8009                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8010                 pedwarn ("ISO C forbids comparison of %<void *%>"
8011                          " with function pointer");
8012             }
8013           else if (VOID_TYPE_P (tt1))
8014             {
8015               if (pedantic && !null_pointer_constant_p (orig_op1)
8016                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8017                 pedwarn ("ISO C forbids comparison of %<void *%>"
8018                          " with function pointer");
8019             }
8020           else
8021             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8022             if (!objc_ok)
8023               pedwarn ("comparison of distinct pointer types lacks a cast");
8024
8025           if (result_type == NULL_TREE)
8026             result_type = ptr_type_node;
8027         }
8028       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8029         {
8030           if (TREE_CODE (op0) == ADDR_EXPR
8031               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8032             warning (OPT_Waddress, "the address of %qD will never be NULL",
8033                      TREE_OPERAND (op0, 0));
8034           result_type = type0;
8035         }
8036       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8037         {
8038           if (TREE_CODE (op1) == ADDR_EXPR
8039               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8040             warning (OPT_Waddress, "the address of %qD will never be NULL",
8041                      TREE_OPERAND (op1, 0));
8042           result_type = type1;
8043         }
8044       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8045         {
8046           result_type = type0;
8047           pedwarn ("comparison between pointer and integer");
8048         }
8049       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8050         {
8051           result_type = type1;
8052           pedwarn ("comparison between pointer and integer");
8053         }
8054       break;
8055
8056     case LE_EXPR:
8057     case GE_EXPR:
8058     case LT_EXPR:
8059     case GT_EXPR:
8060       build_type = integer_type_node;
8061       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
8062           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
8063         short_compare = 1;
8064       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8065         {
8066           if (comp_target_types (type0, type1))
8067             {
8068               result_type = common_pointer_type (type0, type1);
8069               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8070                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8071                 pedwarn ("comparison of complete and incomplete pointers");
8072               else if (pedantic
8073                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8074                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8075             }
8076           else
8077             {
8078               result_type = ptr_type_node;
8079               pedwarn ("comparison of distinct pointer types lacks a cast");
8080             }
8081         }
8082       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8083         {
8084           result_type = type0;
8085           if (pedantic || extra_warnings)
8086             pedwarn ("ordered comparison of pointer with integer zero");
8087         }
8088       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8089         {
8090           result_type = type1;
8091           if (pedantic)
8092             pedwarn ("ordered comparison of pointer with integer zero");
8093         }
8094       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8095         {
8096           result_type = type0;
8097           pedwarn ("comparison between pointer and integer");
8098         }
8099       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8100         {
8101           result_type = type1;
8102           pedwarn ("comparison between pointer and integer");
8103         }
8104       break;
8105
8106     default:
8107       gcc_unreachable ();
8108     }
8109
8110   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8111     return error_mark_node;
8112
8113   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8114       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8115           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8116                                                     TREE_TYPE (type1))))
8117     {
8118       binary_op_error (code);
8119       return error_mark_node;
8120     }
8121
8122   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8123        || code0 == VECTOR_TYPE)
8124       &&
8125       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8126        || code1 == VECTOR_TYPE))
8127     {
8128       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8129
8130       if (shorten || common || short_compare)
8131         result_type = c_common_type (type0, type1);
8132
8133       /* For certain operations (which identify themselves by shorten != 0)
8134          if both args were extended from the same smaller type,
8135          do the arithmetic in that type and then extend.
8136
8137          shorten !=0 and !=1 indicates a bitwise operation.
8138          For them, this optimization is safe only if
8139          both args are zero-extended or both are sign-extended.
8140          Otherwise, we might change the result.
8141          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8142          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8143
8144       if (shorten && none_complex)
8145         {
8146           int unsigned0, unsigned1;
8147           tree arg0, arg1;
8148           int uns;
8149           tree type;
8150
8151           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8152              excessive narrowing when we call get_narrower below.  For
8153              example, suppose that OP0 is of unsigned int extended
8154              from signed char and that RESULT_TYPE is long long int.
8155              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8156              like
8157
8158                (long long int) (unsigned int) signed_char
8159
8160              which get_narrower would narrow down to
8161
8162                (unsigned int) signed char
8163
8164              If we do not cast OP0 first, get_narrower would return
8165              signed_char, which is inconsistent with the case of the
8166              explicit cast.  */
8167           op0 = convert (result_type, op0);
8168           op1 = convert (result_type, op1);
8169
8170           arg0 = get_narrower (op0, &unsigned0);
8171           arg1 = get_narrower (op1, &unsigned1);
8172
8173           /* UNS is 1 if the operation to be done is an unsigned one.  */
8174           uns = TYPE_UNSIGNED (result_type);
8175
8176           final_type = result_type;
8177
8178           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8179              but it *requires* conversion to FINAL_TYPE.  */
8180
8181           if ((TYPE_PRECISION (TREE_TYPE (op0))
8182                == TYPE_PRECISION (TREE_TYPE (arg0)))
8183               && TREE_TYPE (op0) != final_type)
8184             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8185           if ((TYPE_PRECISION (TREE_TYPE (op1))
8186                == TYPE_PRECISION (TREE_TYPE (arg1)))
8187               && TREE_TYPE (op1) != final_type)
8188             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8189
8190           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8191
8192           /* For bitwise operations, signedness of nominal type
8193              does not matter.  Consider only how operands were extended.  */
8194           if (shorten == -1)
8195             uns = unsigned0;
8196
8197           /* Note that in all three cases below we refrain from optimizing
8198              an unsigned operation on sign-extended args.
8199              That would not be valid.  */
8200
8201           /* Both args variable: if both extended in same way
8202              from same width, do it in that width.
8203              Do it unsigned if args were zero-extended.  */
8204           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8205                < TYPE_PRECISION (result_type))
8206               && (TYPE_PRECISION (TREE_TYPE (arg1))
8207                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8208               && unsigned0 == unsigned1
8209               && (unsigned0 || !uns))
8210             result_type
8211               = c_common_signed_or_unsigned_type
8212               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8213           else if (TREE_CODE (arg0) == INTEGER_CST
8214                    && (unsigned1 || !uns)
8215                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8216                        < TYPE_PRECISION (result_type))
8217                    && (type
8218                        = c_common_signed_or_unsigned_type (unsigned1,
8219                                                            TREE_TYPE (arg1)),
8220                        int_fits_type_p (arg0, type)))
8221             result_type = type;
8222           else if (TREE_CODE (arg1) == INTEGER_CST
8223                    && (unsigned0 || !uns)
8224                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8225                        < TYPE_PRECISION (result_type))
8226                    && (type
8227                        = c_common_signed_or_unsigned_type (unsigned0,
8228                                                            TREE_TYPE (arg0)),
8229                        int_fits_type_p (arg1, type)))
8230             result_type = type;
8231         }
8232
8233       /* Shifts can be shortened if shifting right.  */
8234
8235       if (short_shift)
8236         {
8237           int unsigned_arg;
8238           tree arg0 = get_narrower (op0, &unsigned_arg);
8239
8240           final_type = result_type;
8241
8242           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8243             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8244
8245           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8246               /* We can shorten only if the shift count is less than the
8247                  number of bits in the smaller type size.  */
8248               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8249               /* We cannot drop an unsigned shift after sign-extension.  */
8250               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8251             {
8252               /* Do an unsigned shift if the operand was zero-extended.  */
8253               result_type
8254                 = c_common_signed_or_unsigned_type (unsigned_arg,
8255                                                     TREE_TYPE (arg0));
8256               /* Convert value-to-be-shifted to that type.  */
8257               if (TREE_TYPE (op0) != result_type)
8258                 op0 = convert (result_type, op0);
8259               converted = 1;
8260             }
8261         }
8262
8263       /* Comparison operations are shortened too but differently.
8264          They identify themselves by setting short_compare = 1.  */
8265
8266       if (short_compare)
8267         {
8268           /* Don't write &op0, etc., because that would prevent op0
8269              from being kept in a register.
8270              Instead, make copies of the our local variables and
8271              pass the copies by reference, then copy them back afterward.  */
8272           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8273           enum tree_code xresultcode = resultcode;
8274           tree val
8275             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8276
8277           if (val != 0)
8278             return val;
8279
8280           op0 = xop0, op1 = xop1;
8281           converted = 1;
8282           resultcode = xresultcode;
8283
8284           if (warn_sign_compare && skip_evaluation == 0)
8285             {
8286               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8287               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8288               int unsignedp0, unsignedp1;
8289               tree primop0 = get_narrower (op0, &unsignedp0);
8290               tree primop1 = get_narrower (op1, &unsignedp1);
8291
8292               xop0 = orig_op0;
8293               xop1 = orig_op1;
8294               STRIP_TYPE_NOPS (xop0);
8295               STRIP_TYPE_NOPS (xop1);
8296
8297               /* Give warnings for comparisons between signed and unsigned
8298                  quantities that may fail.
8299
8300                  Do the checking based on the original operand trees, so that
8301                  casts will be considered, but default promotions won't be.
8302
8303                  Do not warn if the comparison is being done in a signed type,
8304                  since the signed type will only be chosen if it can represent
8305                  all the values of the unsigned type.  */
8306               if (!TYPE_UNSIGNED (result_type))
8307                 /* OK */;
8308               /* Do not warn if both operands are the same signedness.  */
8309               else if (op0_signed == op1_signed)
8310                 /* OK */;
8311               else
8312                 {
8313                   tree sop, uop;
8314                   bool ovf;
8315
8316                   if (op0_signed)
8317                     sop = xop0, uop = xop1;
8318                   else
8319                     sop = xop1, uop = xop0;
8320
8321                   /* Do not warn if the signed quantity is an
8322                      unsuffixed integer literal (or some static
8323                      constant expression involving such literals or a
8324                      conditional expression involving such literals)
8325                      and it is non-negative.  */
8326                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8327                     /* OK */;
8328                   /* Do not warn if the comparison is an equality operation,
8329                      the unsigned quantity is an integral constant, and it
8330                      would fit in the result if the result were signed.  */
8331                   else if (TREE_CODE (uop) == INTEGER_CST
8332                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8333                            && int_fits_type_p
8334                            (uop, c_common_signed_type (result_type)))
8335                     /* OK */;
8336                   /* Do not warn if the unsigned quantity is an enumeration
8337                      constant and its maximum value would fit in the result
8338                      if the result were signed.  */
8339                   else if (TREE_CODE (uop) == INTEGER_CST
8340                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8341                            && int_fits_type_p
8342                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8343                             c_common_signed_type (result_type)))
8344                     /* OK */;
8345                   else
8346                     warning (0, "comparison between signed and unsigned");
8347                 }
8348
8349               /* Warn if two unsigned values are being compared in a size
8350                  larger than their original size, and one (and only one) is the
8351                  result of a `~' operator.  This comparison will always fail.
8352
8353                  Also warn if one operand is a constant, and the constant
8354                  does not have all bits set that are set in the ~ operand
8355                  when it is extended.  */
8356
8357               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8358                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8359                 {
8360                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8361                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8362                                             &unsignedp0);
8363                   else
8364                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8365                                             &unsignedp1);
8366
8367                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8368                     {
8369                       tree primop;
8370                       HOST_WIDE_INT constant, mask;
8371                       int unsignedp, bits;
8372
8373                       if (host_integerp (primop0, 0))
8374                         {
8375                           primop = primop1;
8376                           unsignedp = unsignedp1;
8377                           constant = tree_low_cst (primop0, 0);
8378                         }
8379                       else
8380                         {
8381                           primop = primop0;
8382                           unsignedp = unsignedp0;
8383                           constant = tree_low_cst (primop1, 0);
8384                         }
8385
8386                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8387                       if (bits < TYPE_PRECISION (result_type)
8388                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8389                         {
8390                           mask = (~(HOST_WIDE_INT) 0) << bits;
8391                           if ((mask & constant) != mask)
8392                             warning (0, "comparison of promoted ~unsigned with constant");
8393                         }
8394                     }
8395                   else if (unsignedp0 && unsignedp1
8396                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8397                                < TYPE_PRECISION (result_type))
8398                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8399                                < TYPE_PRECISION (result_type)))
8400                     warning (0, "comparison of promoted ~unsigned with unsigned");
8401                 }
8402             }
8403         }
8404     }
8405
8406   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8407      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8408      Then the expression will be built.
8409      It will be given type FINAL_TYPE if that is nonzero;
8410      otherwise, it will be given type RESULT_TYPE.  */
8411
8412   if (!result_type)
8413     {
8414       binary_op_error (code);
8415       return error_mark_node;
8416     }
8417
8418   if (!converted)
8419     {
8420       if (TREE_TYPE (op0) != result_type)
8421         op0 = convert_and_check (result_type, op0);
8422       if (TREE_TYPE (op1) != result_type)
8423         op1 = convert_and_check (result_type, op1);
8424
8425       /* This can happen if one operand has a vector type, and the other
8426          has a different type.  */
8427       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8428         return error_mark_node;
8429     }
8430
8431   if (build_type == NULL_TREE)
8432     build_type = result_type;
8433
8434   {
8435     /* Treat expressions in initializers specially as they can't trap.  */
8436     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8437                                                                     build_type,
8438                                                                     op0, op1)
8439                                          : fold_build2 (resultcode, build_type,
8440                                                         op0, op1);
8441
8442     if (final_type != 0)
8443       result = convert (final_type, result);
8444     return result;
8445   }
8446 }
8447
8448
8449 /* Convert EXPR to be a truth-value, validating its type for this
8450    purpose.  */
8451
8452 tree
8453 c_objc_common_truthvalue_conversion (tree expr)
8454 {
8455   switch (TREE_CODE (TREE_TYPE (expr)))
8456     {
8457     case ARRAY_TYPE:
8458       error ("used array that cannot be converted to pointer where scalar is required");
8459       return error_mark_node;
8460
8461     case RECORD_TYPE:
8462       error ("used struct type value where scalar is required");
8463       return error_mark_node;
8464
8465     case UNION_TYPE:
8466       error ("used union type value where scalar is required");
8467       return error_mark_node;
8468
8469     case FUNCTION_TYPE:
8470       gcc_unreachable ();
8471
8472     default:
8473       break;
8474     }
8475
8476   /* ??? Should we also give an error for void and vectors rather than
8477      leaving those to give errors later?  */
8478   return c_common_truthvalue_conversion (expr);
8479 }
8480 \f
8481
8482 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8483    required.  */
8484
8485 tree
8486 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8487                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8488 {
8489   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8490     {
8491       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8492       /* Executing a compound literal inside a function reinitializes
8493          it.  */
8494       if (!TREE_STATIC (decl))
8495         *se = true;
8496       return decl;
8497     }
8498   else
8499     return expr;
8500 }
8501 \f
8502 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8503
8504 tree
8505 c_begin_omp_parallel (void)
8506 {
8507   tree block;
8508
8509   keep_next_level ();
8510   block = c_begin_compound_stmt (true);
8511
8512   return block;
8513 }
8514
8515 tree
8516 c_finish_omp_parallel (tree clauses, tree block)
8517 {
8518   tree stmt;
8519
8520   block = c_end_compound_stmt (block, true);
8521
8522   stmt = make_node (OMP_PARALLEL);
8523   TREE_TYPE (stmt) = void_type_node;
8524   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8525   OMP_PARALLEL_BODY (stmt) = block;
8526
8527   return add_stmt (stmt);
8528 }
8529
8530 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8531    Remove any elements from the list that are invalid.  */
8532
8533 tree
8534 c_finish_omp_clauses (tree clauses)
8535 {
8536   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8537   tree c, t, *pc = &clauses;
8538   const char *name;
8539
8540   bitmap_obstack_initialize (NULL);
8541   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8542   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8543   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8544
8545   for (pc = &clauses, c = clauses; c ; c = *pc)
8546     {
8547       bool remove = false;
8548       bool need_complete = false;
8549       bool need_implicitly_determined = false;
8550
8551       switch (OMP_CLAUSE_CODE (c))
8552         {
8553         case OMP_CLAUSE_SHARED:
8554           name = "shared";
8555           need_implicitly_determined = true;
8556           goto check_dup_generic;
8557
8558         case OMP_CLAUSE_PRIVATE:
8559           name = "private";
8560           need_complete = true;
8561           need_implicitly_determined = true;
8562           goto check_dup_generic;
8563
8564         case OMP_CLAUSE_REDUCTION:
8565           name = "reduction";
8566           need_implicitly_determined = true;
8567           t = OMP_CLAUSE_DECL (c);
8568           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8569               || POINTER_TYPE_P (TREE_TYPE (t)))
8570             {
8571               error ("%qE has invalid type for %<reduction%>", t);
8572               remove = true;
8573             }
8574           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8575             {
8576               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8577               const char *r_name = NULL;
8578
8579               switch (r_code)
8580                 {
8581                 case PLUS_EXPR:
8582                 case MULT_EXPR:
8583                 case MINUS_EXPR:
8584                   break;
8585                 case BIT_AND_EXPR:
8586                   r_name = "&";
8587                   break;
8588                 case BIT_XOR_EXPR:
8589                   r_name = "^";
8590                   break;
8591                 case BIT_IOR_EXPR:
8592                   r_name = "|";
8593                   break;
8594                 case TRUTH_ANDIF_EXPR:
8595                   r_name = "&&";
8596                   break;
8597                 case TRUTH_ORIF_EXPR:
8598                   r_name = "||";
8599                   break;
8600                 default:
8601                   gcc_unreachable ();
8602                 }
8603               if (r_name)
8604                 {
8605                   error ("%qE has invalid type for %<reduction(%s)%>",
8606                          t, r_name);
8607                   remove = true;
8608                 }
8609             }
8610           goto check_dup_generic;
8611
8612         case OMP_CLAUSE_COPYPRIVATE:
8613           name = "copyprivate";
8614           goto check_dup_generic;
8615
8616         case OMP_CLAUSE_COPYIN:
8617           name = "copyin";
8618           t = OMP_CLAUSE_DECL (c);
8619           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8620             {
8621               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8622               remove = true;
8623             }
8624           goto check_dup_generic;
8625
8626         check_dup_generic:
8627           t = OMP_CLAUSE_DECL (c);
8628           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8629             {
8630               error ("%qE is not a variable in clause %qs", t, name);
8631               remove = true;
8632             }
8633           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8634                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8635                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8636             {
8637               error ("%qE appears more than once in data clauses", t);
8638               remove = true;
8639             }
8640           else
8641             bitmap_set_bit (&generic_head, DECL_UID (t));
8642           break;
8643
8644         case OMP_CLAUSE_FIRSTPRIVATE:
8645           name = "firstprivate";
8646           t = OMP_CLAUSE_DECL (c);
8647           need_complete = true;
8648           need_implicitly_determined = true;
8649           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8650             {
8651               error ("%qE is not a variable in clause %<firstprivate%>", t);
8652               remove = true;
8653             }
8654           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8655                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8656             {
8657               error ("%qE appears more than once in data clauses", t);
8658               remove = true;
8659             }
8660           else
8661             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8662           break;
8663
8664         case OMP_CLAUSE_LASTPRIVATE:
8665           name = "lastprivate";
8666           t = OMP_CLAUSE_DECL (c);
8667           need_complete = true;
8668           need_implicitly_determined = true;
8669           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8670             {
8671               error ("%qE is not a variable in clause %<lastprivate%>", t);
8672               remove = true;
8673             }
8674           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8675                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8676             {
8677               error ("%qE appears more than once in data clauses", t);
8678               remove = true;
8679             }
8680           else
8681             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8682           break;
8683
8684         case OMP_CLAUSE_IF:
8685         case OMP_CLAUSE_NUM_THREADS:
8686         case OMP_CLAUSE_SCHEDULE:
8687         case OMP_CLAUSE_NOWAIT:
8688         case OMP_CLAUSE_ORDERED:
8689         case OMP_CLAUSE_DEFAULT:
8690           pc = &OMP_CLAUSE_CHAIN (c);
8691           continue;
8692
8693         default:
8694           gcc_unreachable ();
8695         }
8696
8697       if (!remove)
8698         {
8699           t = OMP_CLAUSE_DECL (c);
8700
8701           if (need_complete)
8702             {
8703               t = require_complete_type (t);
8704               if (t == error_mark_node)
8705                 remove = true;
8706             }
8707
8708           if (need_implicitly_determined)
8709             {
8710               const char *share_name = NULL;
8711
8712               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8713                 share_name = "threadprivate";
8714               else switch (c_omp_predetermined_sharing (t))
8715                 {
8716                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8717                   break;
8718                 case OMP_CLAUSE_DEFAULT_SHARED:
8719                   share_name = "shared";
8720                   break;
8721                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8722                   share_name = "private";
8723                   break;
8724                 default:
8725                   gcc_unreachable ();
8726                 }
8727               if (share_name)
8728                 {
8729                   error ("%qE is predetermined %qs for %qs",
8730                          t, share_name, name);
8731                   remove = true;
8732                 }
8733             }
8734         }
8735
8736       if (remove)
8737         *pc = OMP_CLAUSE_CHAIN (c);
8738       else
8739         pc = &OMP_CLAUSE_CHAIN (c);
8740     }
8741
8742   bitmap_obstack_release (NULL);
8743   return clauses;
8744 }