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
   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 tree convert_arguments (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 void push_array_bounds (int);
  94 static int spelling_length (void);
  95 static char *print_spelling (char *);
  96 static void warning_init (const char *);
  97 static tree digest_init (tree, tree, bool, int);
  98 static void output_init_element (tree, bool, tree, tree, int);
  99 static void output_pending_init_elements (int);
 100 static int set_designator (int);
 101 static void push_range_stack (tree);
 102 static void add_pending_init (tree, tree);
 103 static void set_nonincremental_init (void);
 104 static void set_nonincremental_init_from_string (tree);
 105 static tree find_init_member (tree);
 106 static void readonly_error (tree, enum lvalue_use);
 107 static int lvalue_or_else (tree, enum lvalue_use);
 108 static int lvalue_p (tree);
 109 static void record_maybe_used_decl (tree);
 110 static int comptypes_internal (tree, tree);
 111 \f
 112 /* Return true if EXP is a null pointer constant, false otherwise.  */
 113
 114 static bool
 115 null_pointer_constant_p (tree expr)
 116 {
 117   /* This should really operate on c_expr structures, but they aren't
 118      yet available everywhere required.  */
 119   tree type = TREE_TYPE (expr);
 120   return (TREE_CODE (expr) == INTEGER_CST
 121           && !TREE_CONSTANT_OVERFLOW (expr)
 122           && integer_zerop (expr)
 123           && (INTEGRAL_TYPE_P (type)
 124               || (TREE_CODE (type) == POINTER_TYPE
 125                   && VOID_TYPE_P (TREE_TYPE (type))
 126                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 127 }
 128 \f/* This is a cache to hold if two types are compatible or not.  */
 129
 130 struct tagged_tu_seen_cache {
 131   const struct tagged_tu_seen_cache * next;
 132   tree t1;
 133   tree t2;
 134   /* The return value of tagged_types_tu_compatible_p if we had seen
 135      these two types already.  */
 136   int val;
 137 };
 138
 139 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 140 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 141
 142 /* Do `exp = require_complete_type (exp);' to make sure exp
 143    does not have an incomplete type.  (That includes void types.)  */
 144
 145 tree
 146 require_complete_type (tree value)
 147 {
 148   tree type = TREE_TYPE (value);
 149
 150   if (value == error_mark_node || type == error_mark_node)
 151     return error_mark_node;
 152
 153   /* First, detect a valid value with a complete type.  */
 154   if (COMPLETE_TYPE_P (type))
 155     return value;
 156
 157   c_incomplete_type_error (value, type);
 158   return error_mark_node;
 159 }
 160
 161 /* Print an error message for invalid use of an incomplete type.
 162    VALUE is the expression that was used (or 0 if that isn't known)
 163    and TYPE is the type that was invalid.  */
 164
 165 void
 166 c_incomplete_type_error (tree value, tree type)
 167 {
 168   const char *type_code_string;
 169
 170   /* Avoid duplicate error message.  */
 171   if (TREE_CODE (type) == ERROR_MARK)
 172     return;
 173
 174   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 175                      || TREE_CODE (value) == PARM_DECL))
 176     error ("%qD has an incomplete type", value);
 177   else
 178     {
 179     retry:
 180       /* We must print an error message.  Be clever about what it says.  */
 181
 182       switch (TREE_CODE (type))
 183         {
 184         case RECORD_TYPE:
 185           type_code_string = "struct";
 186           break;
 187
 188         case UNION_TYPE:
 189           type_code_string = "union";
 190           break;
 191
 192         case ENUMERAL_TYPE:
 193           type_code_string = "enum";
 194           break;
 195
 196         case VOID_TYPE:
 197           error ("invalid use of void expression");
 198           return;
 199
 200         case ARRAY_TYPE:
 201           if (TYPE_DOMAIN (type))
 202             {
 203               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 204                 {
 205                   error ("invalid use of flexible array member");
 206                   return;
 207                 }
 208               type = TREE_TYPE (type);
 209               goto retry;
 210             }
 211           error ("invalid use of array with unspecified bounds");
 212           return;
 213
 214         default:
 215           gcc_unreachable ();
 216         }
 217
 218       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 219         error ("invalid use of undefined type %<%s %E%>",
 220                type_code_string, TYPE_NAME (type));
 221       else
 222         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 223         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 224     }
 225 }
 226
 227 /* Given a type, apply default promotions wrt unnamed function
 228    arguments and return the new type.  */
 229
 230 tree
 231 c_type_promotes_to (tree type)
 232 {
 233   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 234     return double_type_node;
 235
 236   if (c_promoting_integer_type_p (type))
 237     {
 238       /* Preserve unsignedness if not really getting any wider.  */
 239       if (TYPE_UNSIGNED (type)
 240           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 241         return unsigned_type_node;
 242       return integer_type_node;
 243     }
 244
 245   return type;
 246 }
 247
 248 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 249    as well as those of TYPE.  */
 250
 251 static tree
 252 qualify_type (tree type, tree like)
 253 {
 254   return c_build_qualified_type (type,
 255                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 256 }
 257 \f
 258 /* Return the composite type of two compatible types.
 259
 260    We assume that comptypes has already been done and returned
 261    nonzero; if that isn't so, this may crash.  In particular, we
 262    assume that qualifiers match.  */
 263
 264 tree
 265 composite_type (tree t1, tree t2)
 266 {
 267   enum tree_code code1;
 268   enum tree_code code2;
 269   tree attributes;
 270
 271   /* Save time if the two types are the same.  */
 272
 273   if (t1 == t2) return t1;
 274
 275   /* If one type is nonsense, use the other.  */
 276   if (t1 == error_mark_node)
 277     return t2;
 278   if (t2 == error_mark_node)
 279     return t1;
 280
 281   code1 = TREE_CODE (t1);
 282   code2 = TREE_CODE (t2);
 283
 284   /* Merge the attributes.  */
 285   attributes = targetm.merge_type_attributes (t1, t2);
 286
 287   /* If one is an enumerated type and the other is the compatible
 288      integer type, the composite type might be either of the two
 289      (DR#013 question 3).  For consistency, use the enumerated type as
 290      the composite type.  */
 291
 292   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 293     return t1;
 294   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 295     return t2;
 296
 297   gcc_assert (code1 == code2);
 298
 299   switch (code1)
 300     {
 301     case POINTER_TYPE:
 302       /* For two pointers, do this recursively on the target type.  */
 303       {
 304         tree pointed_to_1 = TREE_TYPE (t1);
 305         tree pointed_to_2 = TREE_TYPE (t2);
 306         tree target = composite_type (pointed_to_1, pointed_to_2);
 307         t1 = build_pointer_type (target);
 308         t1 = build_type_attribute_variant (t1, attributes);
 309         return qualify_type (t1, t2);
 310       }
 311
 312     case ARRAY_TYPE:
 313       {
 314         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 315         int quals;
 316         tree unqual_elt;
 317         tree d1 = TYPE_DOMAIN (t1);
 318         tree d2 = TYPE_DOMAIN (t2);
 319         bool d1_variable, d2_variable;
 320         bool d1_zero, d2_zero;
 321
 322         /* We should not have any type quals on arrays at all.  */
 323         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 324
 325         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 326         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 327
 328         d1_variable = (!d1_zero
 329                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 330                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 331         d2_variable = (!d2_zero
 332                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 333                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 334
 335         /* Save space: see if the result is identical to one of the args.  */
 336         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 337             && (d2_variable || d2_zero || !d1_variable))
 338           return build_type_attribute_variant (t1, attributes);
 339         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 340             && (d1_variable || d1_zero || !d2_variable))
 341           return build_type_attribute_variant (t2, attributes);
 342
 343         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 344           return build_type_attribute_variant (t1, attributes);
 345         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 346           return build_type_attribute_variant (t2, attributes);
 347
 348         /* Merge the element types, and have a size if either arg has
 349            one.  We may have qualifiers on the element types.  To set
 350            up TYPE_MAIN_VARIANT correctly, we need to form the
 351            composite of the unqualified types and add the qualifiers
 352            back at the end.  */
 353         quals = TYPE_QUALS (strip_array_types (elt));
 354         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 355         t1 = build_array_type (unqual_elt,
 356                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 357                                              && (d2_variable
 358                                                  || d2_zero
 359                                                  || !d1_variable))
 360                                             ? t1
 361                                             : t2));
 362         t1 = c_build_qualified_type (t1, quals);
 363         return build_type_attribute_variant (t1, attributes);
 364       }
 365
 366     case FUNCTION_TYPE:
 367       /* Function types: prefer the one that specified arg types.
 368          If both do, merge the arg types.  Also merge the return types.  */
 369       {
 370         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 371         tree p1 = TYPE_ARG_TYPES (t1);
 372         tree p2 = TYPE_ARG_TYPES (t2);
 373         int len;
 374         tree newargs, n;
 375         int i;
 376
 377         /* Save space: see if the result is identical to one of the args.  */
 378         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 379           return build_type_attribute_variant (t1, attributes);
 380         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 381           return build_type_attribute_variant (t2, attributes);
 382
 383         /* Simple way if one arg fails to specify argument types.  */
 384         if (TYPE_ARG_TYPES (t1) == 0)
 385          {
 386             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 387             t1 = build_type_attribute_variant (t1, attributes);
 388             return qualify_type (t1, t2);
 389          }
 390         if (TYPE_ARG_TYPES (t2) == 0)
 391          {
 392            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 393            t1 = build_type_attribute_variant (t1, attributes);
 394            return qualify_type (t1, t2);
 395          }
 396
 397         /* If both args specify argument types, we must merge the two
 398            lists, argument by argument.  */
 399         /* Tell global_bindings_p to return false so that variable_size
 400            doesn't die on VLAs in parameter types.  */
 401         c_override_global_bindings_to_false = true;
 402
 403         len = list_length (p1);
 404         newargs = 0;
 405
 406         for (i = 0; i < len; i++)
 407           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 408
 409         n = newargs;
 410
 411         for (; p1;
 412              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 413           {
 414             /* A null type means arg type is not specified.
 415                Take whatever the other function type has.  */
 416             if (TREE_VALUE (p1) == 0)
 417               {
 418                 TREE_VALUE (n) = TREE_VALUE (p2);
 419                 goto parm_done;
 420               }
 421             if (TREE_VALUE (p2) == 0)
 422               {
 423                 TREE_VALUE (n) = TREE_VALUE (p1);
 424                 goto parm_done;
 425               }
 426
 427             /* Given  wait (union {union wait *u; int *i} *)
 428                and  wait (union wait *),
 429                prefer  union wait *  as type of parm.  */
 430             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 431                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 432               {
 433                 tree memb;
 434                 tree mv2 = TREE_VALUE (p2);
 435                 if (mv2 && mv2 != error_mark_node
 436                     && TREE_CODE (mv2) != ARRAY_TYPE)
 437                   mv2 = TYPE_MAIN_VARIANT (mv2);
 438                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 439                      memb; memb = TREE_CHAIN (memb))
 440                   {
 441                     tree mv3 = TREE_TYPE (memb);
 442                     if (mv3 && mv3 != error_mark_node
 443                         && TREE_CODE (mv3) != ARRAY_TYPE)
 444                       mv3 = TYPE_MAIN_VARIANT (mv3);
 445                     if (comptypes (mv3, mv2))
 446                       {
 447                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 448                                                          TREE_VALUE (p2));
 449                         if (pedantic)
 450                           pedwarn ("function types not truly compatible in ISO C");
 451                         goto parm_done;
 452                       }
 453                   }
 454               }
 455             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 456                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 457               {
 458                 tree memb;
 459                 tree mv1 = TREE_VALUE (p1);
 460                 if (mv1 && mv1 != error_mark_node
 461                     && TREE_CODE (mv1) != ARRAY_TYPE)
 462                   mv1 = TYPE_MAIN_VARIANT (mv1);
 463                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 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, mv1))
 471                       {
 472                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 473                                                          TREE_VALUE (p1));
 474                         if (pedantic)
 475                           pedwarn ("function types not truly compatible in ISO C");
 476                         goto parm_done;
 477                       }
 478                   }
 479               }
 480             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 481           parm_done: ;
 482           }
 483
 484         c_override_global_bindings_to_false = false;
 485         t1 = build_function_type (valtype, newargs);
 486         t1 = qualify_type (t1, t2);
 487         /* ... falls through ...  */
 488       }
 489
 490     default:
 491       return build_type_attribute_variant (t1, attributes);
 492     }
 493
 494 }
 495
 496 /* Return the type of a conditional expression between pointers to
 497    possibly differently qualified versions of compatible types.
 498
 499    We assume that comp_target_types has already been done and returned
 500    nonzero; if that isn't so, this may crash.  */
 501
 502 static tree
 503 common_pointer_type (tree t1, tree t2)
 504 {
 505   tree attributes;
 506   tree pointed_to_1, mv1;
 507   tree pointed_to_2, mv2;
 508   tree target;
 509
 510   /* Save time if the two types are the same.  */
 511
 512   if (t1 == t2) return t1;
 513
 514   /* If one type is nonsense, use the other.  */
 515   if (t1 == error_mark_node)
 516     return t2;
 517   if (t2 == error_mark_node)
 518     return t1;
 519
 520   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 521               && TREE_CODE (t2) == POINTER_TYPE);
 522
 523   /* Merge the attributes.  */
 524   attributes = targetm.merge_type_attributes (t1, t2);
 525
 526   /* Find the composite type of the target types, and combine the
 527      qualifiers of the two types' targets.  Do not lose qualifiers on
 528      array element types by taking the TYPE_MAIN_VARIANT.  */
 529   mv1 = pointed_to_1 = TREE_TYPE (t1);
 530   mv2 = pointed_to_2 = TREE_TYPE (t2);
 531   if (TREE_CODE (mv1) != ARRAY_TYPE)
 532     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 533   if (TREE_CODE (mv2) != ARRAY_TYPE)
 534     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 535   target = composite_type (mv1, mv2);
 536   t1 = build_pointer_type (c_build_qualified_type
 537                            (target,
 538                             TYPE_QUALS (pointed_to_1) |
 539                             TYPE_QUALS (pointed_to_2)));
 540   return build_type_attribute_variant (t1, attributes);
 541 }
 542
 543 /* Return the common type for two arithmetic types under the usual
 544    arithmetic conversions.  The default conversions have already been
 545    applied, and enumerated types converted to their compatible integer
 546    types.  The resulting type is unqualified and has no attributes.
 547
 548    This is the type for the result of most arithmetic operations
 549    if the operands have the given two types.  */
 550
 551 static tree
 552 c_common_type (tree t1, tree t2)
 553 {
 554   enum tree_code code1;
 555   enum tree_code code2;
 556
 557   /* If one type is nonsense, use the other.  */
 558   if (t1 == error_mark_node)
 559     return t2;
 560   if (t2 == error_mark_node)
 561     return t1;
 562
 563   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 564     t1 = TYPE_MAIN_VARIANT (t1);
 565
 566   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 567     t2 = TYPE_MAIN_VARIANT (t2);
 568
 569   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 570     t1 = build_type_attribute_variant (t1, NULL_TREE);
 571
 572   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 573     t2 = build_type_attribute_variant (t2, NULL_TREE);
 574
 575   /* Save time if the two types are the same.  */
 576
 577   if (t1 == t2) return t1;
 578
 579   code1 = TREE_CODE (t1);
 580   code2 = TREE_CODE (t2);
 581
 582   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 583               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 584   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 585               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 586
 587   /* If one type is a vector type, return that type.  (How the usual
 588      arithmetic conversions apply to the vector types extension is not
 589      precisely specified.)  */
 590   if (code1 == VECTOR_TYPE)
 591     return t1;
 592
 593   if (code2 == VECTOR_TYPE)
 594     return t2;
 595
 596   /* If one type is complex, form the common type of the non-complex
 597      components, then make that complex.  Use T1 or T2 if it is the
 598      required type.  */
 599   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 600     {
 601       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 602       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 603       tree subtype = c_common_type (subtype1, subtype2);
 604
 605       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 606         return t1;
 607       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 608         return t2;
 609       else
 610         return build_complex_type (subtype);
 611     }
 612
 613   /* If only one is real, use it as the result.  */
 614
 615   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 616     return t1;
 617
 618   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 619     return t2;
 620
 621   /* If both are real and either are decimal floating point types, use
 622      the decimal floating point type with the greater precision. */
 623
 624   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 625     {
 626       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 627           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 628         return dfloat128_type_node;
 629       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 630                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 631         return dfloat64_type_node;
 632       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 633                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 634         return dfloat32_type_node;
 635     }
 636
 637   /* Both real or both integers; use the one with greater precision.  */
 638
 639   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 640     return t1;
 641   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 642     return t2;
 643
 644   /* Same precision.  Prefer long longs to longs to ints when the
 645      same precision, following the C99 rules on integer type rank
 646      (which are equivalent to the C90 rules for C90 types).  */
 647
 648   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 649       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 650     return long_long_unsigned_type_node;
 651
 652   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 653       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 654     {
 655       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 656         return long_long_unsigned_type_node;
 657       else
 658         return long_long_integer_type_node;
 659     }
 660
 661   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 662       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 663     return long_unsigned_type_node;
 664
 665   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 666       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 667     {
 668       /* But preserve unsignedness from the other type,
 669          since long cannot hold all the values of an unsigned int.  */
 670       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 671         return long_unsigned_type_node;
 672       else
 673         return long_integer_type_node;
 674     }
 675
 676   /* Likewise, prefer long double to double even if same size.  */
 677   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 678       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 679     return long_double_type_node;
 680
 681   /* Otherwise prefer the unsigned one.  */
 682
 683   if (TYPE_UNSIGNED (t1))
 684     return t1;
 685   else
 686     return t2;
 687 }
 688 \f
 689 /* Wrapper around c_common_type that is used by c-common.c and other
 690    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 691    are allowed here and are converted to their compatible integer types.
 692    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 693    preferably a non-Boolean type as the common type.  */
 694 tree
 695 common_type (tree t1, tree t2)
 696 {
 697   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 698     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 699   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 700     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 701
 702   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 703   if (TREE_CODE (t1) == BOOLEAN_TYPE
 704       && TREE_CODE (t2) == BOOLEAN_TYPE)
 705     return boolean_type_node;
 706
 707   /* If either type is BOOLEAN_TYPE, then return the other.  */
 708   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 709     return t2;
 710   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 711     return t1;
 712
 713   return c_common_type (t1, t2);
 714 }
 715
 716 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 717    or various other operations.  Return 2 if they are compatible
 718    but a warning may be needed if you use them together.  */
 719
 720 int
 721 comptypes (tree type1, tree type2)
 722 {
 723   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 724   int val;
 725
 726   val = comptypes_internal (type1, type2);
 727   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 728
 729   return val;
 730 }\f
 731 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 732    or various other operations.  Return 2 if they are compatible
 733    but a warning may be needed if you use them together.  This
 734    differs from comptypes, in that we don't free the seen types.  */
 735
 736 static int
 737 comptypes_internal (tree type1, tree type2)
 738 {
 739   tree t1 = type1;
 740   tree t2 = type2;
 741   int attrval, val;
 742
 743   /* Suppress errors caused by previously reported errors.  */
 744
 745   if (t1 == t2 || !t1 || !t2
 746       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 747     return 1;
 748
 749   /* If either type is the internal version of sizetype, return the
 750      language version.  */
 751   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 752       && TYPE_ORIG_SIZE_TYPE (t1))
 753     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 754
 755   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 756       && TYPE_ORIG_SIZE_TYPE (t2))
 757     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 758
 759
 760   /* Enumerated types are compatible with integer types, but this is
 761      not transitive: two enumerated types in the same translation unit
 762      are compatible with each other only if they are the same type.  */
 763
 764   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 765     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 766   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 767     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 768
 769   if (t1 == t2)
 770     return 1;
 771
 772   /* Different classes of types can't be compatible.  */
 773
 774   if (TREE_CODE (t1) != TREE_CODE (t2))
 775     return 0;
 776
 777   /* Qualifiers must match. C99 6.7.3p9 */
 778
 779   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 780     return 0;
 781
 782   /* Allow for two different type nodes which have essentially the same
 783      definition.  Note that we already checked for equality of the type
 784      qualifiers (just above).  */
 785
 786   if (TREE_CODE (t1) != ARRAY_TYPE
 787       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 788     return 1;
 789
 790   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 791   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 792      return 0;
 793
 794   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 795   val = 0;
 796
 797   switch (TREE_CODE (t1))
 798     {
 799     case POINTER_TYPE:
 800       /* Do not remove mode or aliasing information.  */
 801       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 802           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 803         break;
 804       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 805              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 806       break;
 807
 808     case FUNCTION_TYPE:
 809       val = function_types_compatible_p (t1, t2);
 810       break;
 811
 812     case ARRAY_TYPE:
 813       {
 814         tree d1 = TYPE_DOMAIN (t1);
 815         tree d2 = TYPE_DOMAIN (t2);
 816         bool d1_variable, d2_variable;
 817         bool d1_zero, d2_zero;
 818         val = 1;
 819
 820         /* Target types must match incl. qualifiers.  */
 821         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 822             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 823           return 0;
 824
 825         /* Sizes must match unless one is missing or variable.  */
 826         if (d1 == 0 || d2 == 0 || d1 == d2)
 827           break;
 828
 829         d1_zero = !TYPE_MAX_VALUE (d1);
 830         d2_zero = !TYPE_MAX_VALUE (d2);
 831
 832         d1_variable = (!d1_zero
 833                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 834                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 835         d2_variable = (!d2_zero
 836                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 837                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 838
 839         if (d1_variable || d2_variable)
 840           break;
 841         if (d1_zero && d2_zero)
 842           break;
 843         if (d1_zero || d2_zero
 844             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 845             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 846           val = 0;
 847
 848         break;
 849       }
 850
 851     case ENUMERAL_TYPE:
 852     case RECORD_TYPE:
 853     case UNION_TYPE:
 854       if (val != 1 && !same_translation_unit_p (t1, t2))
 855         {
 856           if (attrval != 2)
 857             return tagged_types_tu_compatible_p (t1, t2);
 858           val = tagged_types_tu_compatible_p (t1, t2);
 859         }
 860       break;
 861
 862     case VECTOR_TYPE:
 863       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 864             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
 865       break;
 866
 867     default:
 868       break;
 869     }
 870   return attrval == 2 && val == 1 ? 2 : val;
 871 }
 872
 873 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 874    ignoring their qualifiers.  */
 875
 876 static int
 877 comp_target_types (tree ttl, tree ttr)
 878 {
 879   int val;
 880   tree mvl, mvr;
 881
 882   /* Do not lose qualifiers on element types of array types that are
 883      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 884   mvl = TREE_TYPE (ttl);
 885   mvr = TREE_TYPE (ttr);
 886   if (TREE_CODE (mvl) != ARRAY_TYPE)
 887     mvl = TYPE_MAIN_VARIANT (mvl);
 888   if (TREE_CODE (mvr) != ARRAY_TYPE)
 889     mvr = TYPE_MAIN_VARIANT (mvr);
 890   val = comptypes (mvl, mvr);
 891
 892   if (val == 2 && pedantic)
 893     pedwarn ("types are not quite compatible");
 894   return val;
 895 }
 896 \f
 897 /* Subroutines of `comptypes'.  */
 898
 899 /* Determine whether two trees derive from the same translation unit.
 900    If the CONTEXT chain ends in a null, that tree's context is still
 901    being parsed, so if two trees have context chains ending in null,
 902    they're in the same translation unit.  */
 903 int
 904 same_translation_unit_p (tree t1, tree t2)
 905 {
 906   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 907     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 908       {
 909       case tcc_declaration:
 910         t1 = DECL_CONTEXT (t1); break;
 911       case tcc_type:
 912         t1 = TYPE_CONTEXT (t1); break;
 913       case tcc_exceptional:
 914         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 915       default: gcc_unreachable ();
 916       }
 917
 918   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 919     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 920       {
 921       case tcc_declaration:
 922         t2 = DECL_CONTEXT (t2); break;
 923       case tcc_type:
 924         t2 = TYPE_CONTEXT (t2); break;
 925       case tcc_exceptional:
 926         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 927       default: gcc_unreachable ();
 928       }
 929
 930   return t1 == t2;
 931 }
 932
 933 /* Allocate the seen two types, assuming that they are compatible. */
 934
 935 static struct tagged_tu_seen_cache *
 936 alloc_tagged_tu_seen_cache (tree t1, tree t2)
 937 {
 938   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
 939   tu->next = tagged_tu_seen_base;
 940   tu->t1 = t1;
 941   tu->t2 = t2;
 942
 943   tagged_tu_seen_base = tu;
 944
 945   /* The C standard says that two structures in different translation
 946      units are compatible with each other only if the types of their
 947      fields are compatible (among other things).  We assume that they
 948      are compatible until proven otherwise when building the cache.
 949      An example where this can occur is:
 950      struct a
 951      {
 952        struct a *next;
 953      };
 954      If we are comparing this against a similar struct in another TU,
 955      and did not assume they were compatible, we end up with an infinite
 956      loop.  */
 957   tu->val = 1;
 958   return tu;
 959 }
 960
 961 /* Free the seen types until we get to TU_TIL. */
 962
 963 static void
 964 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
 965 {
 966   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
 967   while (tu != tu_til)
 968     {
 969       struct tagged_tu_seen_cache *tu1 = (struct tagged_tu_seen_cache*)tu;
 970       tu = tu1->next;
 971       free (tu1);
 972     }
 973   tagged_tu_seen_base = tu_til;
 974 }
 975
 976 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 977    compatible.  If the two types are not the same (which has been
 978    checked earlier), this can only happen when multiple translation
 979    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 980    rules.  */
 981
 982 static int
 983 tagged_types_tu_compatible_p (tree t1, tree t2)
 984 {
 985   tree s1, s2;
 986   bool needs_warning = false;
 987
 988   /* We have to verify that the tags of the types are the same.  This
 989      is harder than it looks because this may be a typedef, so we have
 990      to go look at the original type.  It may even be a typedef of a
 991      typedef...
 992      In the case of compiler-created builtin structs the TYPE_DECL
 993      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 994   while (TYPE_NAME (t1)
 995          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 996          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 997     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 998
 999   while (TYPE_NAME (t2)
1000          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1001          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1002     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1003
1004   /* C90 didn't have the requirement that the two tags be the same.  */
1005   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1006     return 0;
1007
1008   /* C90 didn't say what happened if one or both of the types were
1009      incomplete; we choose to follow C99 rules here, which is that they
1010      are compatible.  */
1011   if (TYPE_SIZE (t1) == NULL
1012       || TYPE_SIZE (t2) == NULL)
1013     return 1;
1014
1015   {
1016     const struct tagged_tu_seen_cache * tts_i;
1017     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1018       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1019         return tts_i->val;
1020   }
1021
1022   switch (TREE_CODE (t1))
1023     {
1024     case ENUMERAL_TYPE:
1025       {
1026         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1027         /* Speed up the case where the type values are in the same order.  */
1028         tree tv1 = TYPE_VALUES (t1);
1029         tree tv2 = TYPE_VALUES (t2);
1030
1031         if (tv1 == tv2)
1032           {
1033             return 1;
1034           }
1035
1036         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1037           {
1038             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1039               break;
1040             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1041               {
1042                 tu->val = 0;
1043                 return 0;
1044               }
1045           }
1046
1047         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1048           {
1049             return 1;
1050           }
1051         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1052           {
1053             tu->val = 0;
1054             return 0;
1055           }
1056
1057         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1058           {
1059             tu->val = 0;
1060             return 0;
1061           }
1062
1063         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1064           {
1065             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1066             if (s2 == NULL
1067                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1068               {
1069                 tu->val = 0;
1070                 return 0;
1071               }
1072           }
1073         return 1;
1074       }
1075
1076     case UNION_TYPE:
1077       {
1078         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1079         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1080           {
1081             tu->val = 0;
1082             return 0;
1083           }
1084
1085         /*  Speed up the common case where the fields are in the same order. */
1086         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1087              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1088           {
1089             int result;
1090
1091
1092             if (DECL_NAME (s1) == NULL
1093                 || DECL_NAME (s1) != DECL_NAME (s2))
1094               break;
1095             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1096             if (result == 0)
1097               {
1098                 tu->val = 0;
1099                 return 0;
1100               }
1101             if (result == 2)
1102               needs_warning = true;
1103
1104             if (TREE_CODE (s1) == FIELD_DECL
1105                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1106                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1107               {
1108                 tu->val = 0;
1109                 return 0;
1110               }
1111           }
1112         if (!s1 && !s2)
1113           {
1114             tu->val = needs_warning ? 2 : 1;
1115             return tu->val;
1116           }
1117
1118         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1119           {
1120             bool ok = false;
1121
1122             if (DECL_NAME (s1) != NULL)
1123               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1124                 if (DECL_NAME (s1) == DECL_NAME (s2))
1125                   {
1126                     int result;
1127                     result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1128                     if (result == 0)
1129                       {
1130                         tu->val = 0;
1131                         return 0;
1132                       }
1133                     if (result == 2)
1134                       needs_warning = true;
1135
1136                     if (TREE_CODE (s1) == FIELD_DECL
1137                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1138                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
1139                       break;
1140
1141                     ok = true;
1142                     break;
1143                   }
1144             if (!ok)
1145               {
1146                 tu->val = 0;
1147                 return 0;
1148               }
1149           }
1150         tu->val = needs_warning ? 2 : 10;
1151         return tu->val;
1152       }
1153
1154     case RECORD_TYPE:
1155       {
1156         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1157
1158         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1159              s1 && s2;
1160              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1161           {
1162             int result;
1163             if (TREE_CODE (s1) != TREE_CODE (s2)
1164                 || DECL_NAME (s1) != DECL_NAME (s2))
1165               break;
1166             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1167             if (result == 0)
1168               break;
1169             if (result == 2)
1170               needs_warning = true;
1171
1172             if (TREE_CODE (s1) == FIELD_DECL
1173                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1174                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1175               break;
1176           }
1177         if (s1 && s2)
1178           tu->val = 0;
1179         else
1180           tu->val = needs_warning ? 2 : 1;
1181         return tu->val;
1182       }
1183
1184     default:
1185       gcc_unreachable ();
1186     }
1187 }
1188
1189 /* Return 1 if two function types F1 and F2 are compatible.
1190    If either type specifies no argument types,
1191    the other must specify a fixed number of self-promoting arg types.
1192    Otherwise, if one type specifies only the number of arguments,
1193    the other must specify that number of self-promoting arg types.
1194    Otherwise, the argument types must match.  */
1195
1196 static int
1197 function_types_compatible_p (tree f1, tree f2)
1198 {
1199   tree args1, args2;
1200   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1201   int val = 1;
1202   int val1;
1203   tree ret1, ret2;
1204
1205   ret1 = TREE_TYPE (f1);
1206   ret2 = TREE_TYPE (f2);
1207
1208   /* 'volatile' qualifiers on a function's return type used to mean
1209      the function is noreturn.  */
1210   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1211     pedwarn ("function return types not compatible due to %<volatile%>");
1212   if (TYPE_VOLATILE (ret1))
1213     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1214                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1215   if (TYPE_VOLATILE (ret2))
1216     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1217                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1218   val = comptypes_internal (ret1, ret2);
1219   if (val == 0)
1220     return 0;
1221
1222   args1 = TYPE_ARG_TYPES (f1);
1223   args2 = TYPE_ARG_TYPES (f2);
1224
1225   /* An unspecified parmlist matches any specified parmlist
1226      whose argument types don't need default promotions.  */
1227
1228   if (args1 == 0)
1229     {
1230       if (!self_promoting_args_p (args2))
1231         return 0;
1232       /* If one of these types comes from a non-prototype fn definition,
1233          compare that with the other type's arglist.
1234          If they don't match, ask for a warning (but no error).  */
1235       if (TYPE_ACTUAL_ARG_TYPES (f1)
1236           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1237         val = 2;
1238       return val;
1239     }
1240   if (args2 == 0)
1241     {
1242       if (!self_promoting_args_p (args1))
1243         return 0;
1244       if (TYPE_ACTUAL_ARG_TYPES (f2)
1245           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1246         val = 2;
1247       return val;
1248     }
1249
1250   /* Both types have argument lists: compare them and propagate results.  */
1251   val1 = type_lists_compatible_p (args1, args2);
1252   return val1 != 1 ? val1 : val;
1253 }
1254
1255 /* Check two lists of types for compatibility,
1256    returning 0 for incompatible, 1 for compatible,
1257    or 2 for compatible with warning.  */
1258
1259 static int
1260 type_lists_compatible_p (tree args1, tree args2)
1261 {
1262   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1263   int val = 1;
1264   int newval = 0;
1265
1266   while (1)
1267     {
1268       tree a1, mv1, a2, mv2;
1269       if (args1 == 0 && args2 == 0)
1270         return val;
1271       /* If one list is shorter than the other,
1272          they fail to match.  */
1273       if (args1 == 0 || args2 == 0)
1274         return 0;
1275       mv1 = a1 = TREE_VALUE (args1);
1276       mv2 = a2 = TREE_VALUE (args2);
1277       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1278         mv1 = TYPE_MAIN_VARIANT (mv1);
1279       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1280         mv2 = TYPE_MAIN_VARIANT (mv2);
1281       /* A null pointer instead of a type
1282          means there is supposed to be an argument
1283          but nothing is specified about what type it has.
1284          So match anything that self-promotes.  */
1285       if (a1 == 0)
1286         {
1287           if (c_type_promotes_to (a2) != a2)
1288             return 0;
1289         }
1290       else if (a2 == 0)
1291         {
1292           if (c_type_promotes_to (a1) != a1)
1293             return 0;
1294         }
1295       /* If one of the lists has an error marker, ignore this arg.  */
1296       else if (TREE_CODE (a1) == ERROR_MARK
1297                || TREE_CODE (a2) == ERROR_MARK)
1298         ;
1299       else if (!(newval = comptypes_internal (mv1, mv2)))
1300         {
1301           /* Allow  wait (union {union wait *u; int *i} *)
1302              and  wait (union wait *)  to be compatible.  */
1303           if (TREE_CODE (a1) == UNION_TYPE
1304               && (TYPE_NAME (a1) == 0
1305                   || TYPE_TRANSPARENT_UNION (a1))
1306               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1307               && tree_int_cst_equal (TYPE_SIZE (a1),
1308                                      TYPE_SIZE (a2)))
1309             {
1310               tree memb;
1311               for (memb = TYPE_FIELDS (a1);
1312                    memb; memb = TREE_CHAIN (memb))
1313                 {
1314                   tree mv3 = TREE_TYPE (memb);
1315                   if (mv3 && mv3 != error_mark_node
1316                       && TREE_CODE (mv3) != ARRAY_TYPE)
1317                     mv3 = TYPE_MAIN_VARIANT (mv3);
1318                   if (comptypes_internal (mv3, mv2))
1319                     break;
1320                 }
1321               if (memb == 0)
1322                 return 0;
1323             }
1324           else if (TREE_CODE (a2) == UNION_TYPE
1325                    && (TYPE_NAME (a2) == 0
1326                        || TYPE_TRANSPARENT_UNION (a2))
1327                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1328                    && tree_int_cst_equal (TYPE_SIZE (a2),
1329                                           TYPE_SIZE (a1)))
1330             {
1331               tree memb;
1332               for (memb = TYPE_FIELDS (a2);
1333                    memb; memb = TREE_CHAIN (memb))
1334                 {
1335                   tree mv3 = TREE_TYPE (memb);
1336                   if (mv3 && mv3 != error_mark_node
1337                       && TREE_CODE (mv3) != ARRAY_TYPE)
1338                     mv3 = TYPE_MAIN_VARIANT (mv3);
1339                   if (comptypes_internal (mv3, mv1))
1340                     break;
1341                 }
1342               if (memb == 0)
1343                 return 0;
1344             }
1345           else
1346             return 0;
1347         }
1348
1349       /* comptypes said ok, but record if it said to warn.  */
1350       if (newval > val)
1351         val = newval;
1352
1353       args1 = TREE_CHAIN (args1);
1354       args2 = TREE_CHAIN (args2);
1355     }
1356 }
1357 \f
1358 /* Compute the size to increment a pointer by.  */
1359
1360 static tree
1361 c_size_in_bytes (tree type)
1362 {
1363   enum tree_code code = TREE_CODE (type);
1364
1365   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1366     return size_one_node;
1367
1368   if (!COMPLETE_OR_VOID_TYPE_P (type))
1369     {
1370       error ("arithmetic on pointer to an incomplete type");
1371       return size_one_node;
1372     }
1373
1374   /* Convert in case a char is more than one unit.  */
1375   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1376                      size_int (TYPE_PRECISION (char_type_node)
1377                                / BITS_PER_UNIT));
1378 }
1379 \f
1380 /* Return either DECL or its known constant value (if it has one).  */
1381
1382 tree
1383 decl_constant_value (tree decl)
1384 {
1385   if (/* Don't change a variable array bound or initial value to a constant
1386          in a place where a variable is invalid.  Note that DECL_INITIAL
1387          isn't valid for a PARM_DECL.  */
1388       current_function_decl != 0
1389       && TREE_CODE (decl) != PARM_DECL
1390       && !TREE_THIS_VOLATILE (decl)
1391       && TREE_READONLY (decl)
1392       && DECL_INITIAL (decl) != 0
1393       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1394       /* This is invalid if initial value is not constant.
1395          If it has either a function call, a memory reference,
1396          or a variable, then re-evaluating it could give different results.  */
1397       && TREE_CONSTANT (DECL_INITIAL (decl))
1398       /* Check for cases where this is sub-optimal, even though valid.  */
1399       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1400     return DECL_INITIAL (decl);
1401   return decl;
1402 }
1403
1404 /* Return either DECL or its known constant value (if it has one), but
1405    return DECL if pedantic or DECL has mode BLKmode.  This is for
1406    bug-compatibility with the old behavior of decl_constant_value
1407    (before GCC 3.0); every use of this function is a bug and it should
1408    be removed before GCC 3.1.  It is not appropriate to use pedantic
1409    in a way that affects optimization, and BLKmode is probably not the
1410    right test for avoiding misoptimizations either.  */
1411
1412 static tree
1413 decl_constant_value_for_broken_optimization (tree decl)
1414 {
1415   tree ret;
1416
1417   if (pedantic || DECL_MODE (decl) == BLKmode)
1418     return decl;
1419
1420   ret = decl_constant_value (decl);
1421   /* Avoid unwanted tree sharing between the initializer and current
1422      function's body where the tree can be modified e.g. by the
1423      gimplifier.  */
1424   if (ret != decl && TREE_STATIC (decl))
1425     ret = unshare_expr (ret);
1426   return ret;
1427 }
1428
1429 /* Convert the array expression EXP to a pointer.  */
1430 static tree
1431 array_to_pointer_conversion (tree exp)
1432 {
1433   tree orig_exp = exp;
1434   tree type = TREE_TYPE (exp);
1435   tree adr;
1436   tree restype = TREE_TYPE (type);
1437   tree ptrtype;
1438
1439   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1440
1441   STRIP_TYPE_NOPS (exp);
1442
1443   if (TREE_NO_WARNING (orig_exp))
1444     TREE_NO_WARNING (exp) = 1;
1445
1446   ptrtype = build_pointer_type (restype);
1447
1448   if (TREE_CODE (exp) == INDIRECT_REF)
1449     return convert (ptrtype, TREE_OPERAND (exp, 0));
1450
1451   if (TREE_CODE (exp) == VAR_DECL)
1452     {
1453       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1454          ADDR_EXPR because it's the best way of representing what
1455          happens in C when we take the address of an array and place
1456          it in a pointer to the element type.  */
1457       adr = build1 (ADDR_EXPR, ptrtype, exp);
1458       if (!c_mark_addressable (exp))
1459         return error_mark_node;
1460       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1461       return adr;
1462     }
1463
1464   /* This way is better for a COMPONENT_REF since it can
1465      simplify the offset for a component.  */
1466   adr = build_unary_op (ADDR_EXPR, exp, 1);
1467   return convert (ptrtype, adr);
1468 }
1469
1470 /* Convert the function expression EXP to a pointer.  */
1471 static tree
1472 function_to_pointer_conversion (tree exp)
1473 {
1474   tree orig_exp = exp;
1475
1476   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1477
1478   STRIP_TYPE_NOPS (exp);
1479
1480   if (TREE_NO_WARNING (orig_exp))
1481     TREE_NO_WARNING (exp) = 1;
1482
1483   return build_unary_op (ADDR_EXPR, exp, 0);
1484 }
1485
1486 /* Perform the default conversion of arrays and functions to pointers.
1487    Return the result of converting EXP.  For any other expression, just
1488    return EXP after removing NOPs.  */
1489
1490 struct c_expr
1491 default_function_array_conversion (struct c_expr exp)
1492 {
1493   tree orig_exp = exp.value;
1494   tree type = TREE_TYPE (exp.value);
1495   enum tree_code code = TREE_CODE (type);
1496
1497   switch (code)
1498     {
1499     case ARRAY_TYPE:
1500       {
1501         bool not_lvalue = false;
1502         bool lvalue_array_p;
1503
1504         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1505                 || TREE_CODE (exp.value) == NOP_EXPR
1506                 || TREE_CODE (exp.value) == CONVERT_EXPR)
1507                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1508           {
1509             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1510               not_lvalue = true;
1511             exp.value = TREE_OPERAND (exp.value, 0);
1512           }
1513
1514         if (TREE_NO_WARNING (orig_exp))
1515           TREE_NO_WARNING (exp.value) = 1;
1516
1517         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1518         if (!flag_isoc99 && !lvalue_array_p)
1519           {
1520             /* Before C99, non-lvalue arrays do not decay to pointers.
1521                Normally, using such an array would be invalid; but it can
1522                be used correctly inside sizeof or as a statement expression.
1523                Thus, do not give an error here; an error will result later.  */
1524             return exp;
1525           }
1526
1527         exp.value = array_to_pointer_conversion (exp.value);
1528       }
1529       break;
1530     case FUNCTION_TYPE:
1531       exp.value = function_to_pointer_conversion (exp.value);
1532       break;
1533     default:
1534       STRIP_TYPE_NOPS (exp.value);
1535       if (TREE_NO_WARNING (orig_exp))
1536         TREE_NO_WARNING (exp.value) = 1;
1537       break;
1538     }
1539
1540   return exp;
1541 }
1542
1543
1544 /* EXP is an expression of integer type.  Apply the integer promotions
1545    to it and return the promoted value.  */
1546
1547 tree
1548 perform_integral_promotions (tree exp)
1549 {
1550   tree type = TREE_TYPE (exp);
1551   enum tree_code code = TREE_CODE (type);
1552
1553   gcc_assert (INTEGRAL_TYPE_P (type));
1554
1555   /* Normally convert enums to int,
1556      but convert wide enums to something wider.  */
1557   if (code == ENUMERAL_TYPE)
1558     {
1559       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1560                                           TYPE_PRECISION (integer_type_node)),
1561                                      ((TYPE_PRECISION (type)
1562                                        >= TYPE_PRECISION (integer_type_node))
1563                                       && TYPE_UNSIGNED (type)));
1564
1565       return convert (type, exp);
1566     }
1567
1568   /* ??? This should no longer be needed now bit-fields have their
1569      proper types.  */
1570   if (TREE_CODE (exp) == COMPONENT_REF
1571       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1572       /* If it's thinner than an int, promote it like a
1573          c_promoting_integer_type_p, otherwise leave it alone.  */
1574       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1575                                TYPE_PRECISION (integer_type_node)))
1576     return convert (integer_type_node, exp);
1577
1578   if (c_promoting_integer_type_p (type))
1579     {
1580       /* Preserve unsignedness if not really getting any wider.  */
1581       if (TYPE_UNSIGNED (type)
1582           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1583         return convert (unsigned_type_node, exp);
1584
1585       return convert (integer_type_node, exp);
1586     }
1587
1588   return exp;
1589 }
1590
1591
1592 /* Perform default promotions for C data used in expressions.
1593    Enumeral types or short or char are converted to int.
1594    In addition, manifest constants symbols are replaced by their values.  */
1595
1596 tree
1597 default_conversion (tree exp)
1598 {
1599   tree orig_exp;
1600   tree type = TREE_TYPE (exp);
1601   enum tree_code code = TREE_CODE (type);
1602
1603   /* Functions and arrays have been converted during parsing.  */
1604   gcc_assert (code != FUNCTION_TYPE);
1605   if (code == ARRAY_TYPE)
1606     return exp;
1607
1608   /* Constants can be used directly unless they're not loadable.  */
1609   if (TREE_CODE (exp) == CONST_DECL)
1610     exp = DECL_INITIAL (exp);
1611
1612   /* Replace a nonvolatile const static variable with its value unless
1613      it is an array, in which case we must be sure that taking the
1614      address of the array produces consistent results.  */
1615   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1616     {
1617       exp = decl_constant_value_for_broken_optimization (exp);
1618       type = TREE_TYPE (exp);
1619     }
1620
1621   /* Strip no-op conversions.  */
1622   orig_exp = exp;
1623   STRIP_TYPE_NOPS (exp);
1624
1625   if (TREE_NO_WARNING (orig_exp))
1626     TREE_NO_WARNING (exp) = 1;
1627
1628   if (INTEGRAL_TYPE_P (type))
1629     return perform_integral_promotions (exp);
1630
1631   if (code == VOID_TYPE)
1632     {
1633       error ("void value not ignored as it ought to be");
1634       return error_mark_node;
1635     }
1636   return exp;
1637 }
1638 \f
1639 /* Look up COMPONENT in a structure or union DECL.
1640
1641    If the component name is not found, returns NULL_TREE.  Otherwise,
1642    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1643    stepping down the chain to the component, which is in the last
1644    TREE_VALUE of the list.  Normally the list is of length one, but if
1645    the component is embedded within (nested) anonymous structures or
1646    unions, the list steps down the chain to the component.  */
1647
1648 static tree
1649 lookup_field (tree decl, tree component)
1650 {
1651   tree type = TREE_TYPE (decl);
1652   tree field;
1653
1654   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1655      to the field elements.  Use a binary search on this array to quickly
1656      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1657      will always be set for structures which have many elements.  */
1658
1659   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1660     {
1661       int bot, top, half;
1662       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1663
1664       field = TYPE_FIELDS (type);
1665       bot = 0;
1666       top = TYPE_LANG_SPECIFIC (type)->s->len;
1667       while (top - bot > 1)
1668         {
1669           half = (top - bot + 1) >> 1;
1670           field = field_array[bot+half];
1671
1672           if (DECL_NAME (field) == NULL_TREE)
1673             {
1674               /* Step through all anon unions in linear fashion.  */
1675               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1676                 {
1677                   field = field_array[bot++];
1678                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1679                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1680                     {
1681                       tree anon = lookup_field (field, component);
1682
1683                       if (anon)
1684                         return tree_cons (NULL_TREE, field, anon);
1685                     }
1686                 }
1687
1688               /* Entire record is only anon unions.  */
1689               if (bot > top)
1690                 return NULL_TREE;
1691
1692               /* Restart the binary search, with new lower bound.  */
1693               continue;
1694             }
1695
1696           if (DECL_NAME (field) == component)
1697             break;
1698           if (DECL_NAME (field) < component)
1699             bot += half;
1700           else
1701             top = bot + half;
1702         }
1703
1704       if (DECL_NAME (field_array[bot]) == component)
1705         field = field_array[bot];
1706       else if (DECL_NAME (field) != component)
1707         return NULL_TREE;
1708     }
1709   else
1710     {
1711       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1712         {
1713           if (DECL_NAME (field) == NULL_TREE
1714               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1715                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1716             {
1717               tree anon = lookup_field (field, component);
1718
1719               if (anon)
1720                 return tree_cons (NULL_TREE, field, anon);
1721             }
1722
1723           if (DECL_NAME (field) == component)
1724             break;
1725         }
1726
1727       if (field == NULL_TREE)
1728         return NULL_TREE;
1729     }
1730
1731   return tree_cons (NULL_TREE, field, NULL_TREE);
1732 }
1733
1734 /* Make an expression to refer to the COMPONENT field of
1735    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1736
1737 tree
1738 build_component_ref (tree datum, tree component)
1739 {
1740   tree type = TREE_TYPE (datum);
1741   enum tree_code code = TREE_CODE (type);
1742   tree field = NULL;
1743   tree ref;
1744
1745   if (!objc_is_public (datum, component))
1746     return error_mark_node;
1747
1748   /* See if there is a field or component with name COMPONENT.  */
1749
1750   if (code == RECORD_TYPE || code == UNION_TYPE)
1751     {
1752       if (!COMPLETE_TYPE_P (type))
1753         {
1754           c_incomplete_type_error (NULL_TREE, type);
1755           return error_mark_node;
1756         }
1757
1758       field = lookup_field (datum, component);
1759
1760       if (!field)
1761         {
1762           error ("%qT has no member named %qE", type, component);
1763           return error_mark_node;
1764         }
1765
1766       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1767          This might be better solved in future the way the C++ front
1768          end does it - by giving the anonymous entities each a
1769          separate name and type, and then have build_component_ref
1770          recursively call itself.  We can't do that here.  */
1771       do
1772         {
1773           tree subdatum = TREE_VALUE (field);
1774
1775           if (TREE_TYPE (subdatum) == error_mark_node)
1776             return error_mark_node;
1777
1778           ref = build3 (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1779                         NULL_TREE);
1780           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1781             TREE_READONLY (ref) = 1;
1782           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1783             TREE_THIS_VOLATILE (ref) = 1;
1784
1785           if (TREE_DEPRECATED (subdatum))
1786             warn_deprecated_use (subdatum);
1787
1788           datum = ref;
1789
1790           field = TREE_CHAIN (field);
1791         }
1792       while (field);
1793
1794       return ref;
1795     }
1796   else if (code != ERROR_MARK)
1797     error ("request for member %qE in something not a structure or union",
1798            component);
1799
1800   return error_mark_node;
1801 }
1802 \f
1803 /* Given an expression PTR for a pointer, return an expression
1804    for the value pointed to.
1805    ERRORSTRING is the name of the operator to appear in error messages.  */
1806
1807 tree
1808 build_indirect_ref (tree ptr, const char *errorstring)
1809 {
1810   tree pointer = default_conversion (ptr);
1811   tree type = TREE_TYPE (pointer);
1812
1813   if (TREE_CODE (type) == POINTER_TYPE)
1814     {
1815       if (TREE_CODE (pointer) == ADDR_EXPR
1816           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1817               == TREE_TYPE (type)))
1818         return TREE_OPERAND (pointer, 0);
1819       else
1820         {
1821           tree t = TREE_TYPE (type);
1822           tree ref;
1823
1824           ref = build1 (INDIRECT_REF, t, pointer);
1825
1826           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1827             {
1828               error ("dereferencing pointer to incomplete type");
1829               return error_mark_node;
1830             }
1831           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1832             warning (0, "dereferencing %<void *%> pointer");
1833
1834           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1835              so that we get the proper error message if the result is used
1836              to assign to.  Also, &* is supposed to be a no-op.
1837              And ANSI C seems to specify that the type of the result
1838              should be the const type.  */
1839           /* A de-reference of a pointer to const is not a const.  It is valid
1840              to change it via some other pointer.  */
1841           TREE_READONLY (ref) = TYPE_READONLY (t);
1842           TREE_SIDE_EFFECTS (ref)
1843             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1844           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1845           return ref;
1846         }
1847     }
1848   else if (TREE_CODE (pointer) != ERROR_MARK)
1849     error ("invalid type argument of %qs", errorstring);
1850   return error_mark_node;
1851 }
1852
1853 /* This handles expressions of the form "a[i]", which denotes
1854    an array reference.
1855
1856    This is logically equivalent in C to *(a+i), but we may do it differently.
1857    If A is a variable or a member, we generate a primitive ARRAY_REF.
1858    This avoids forcing the array out of registers, and can work on
1859    arrays that are not lvalues (for example, members of structures returned
1860    by functions).  */
1861
1862 tree
1863 build_array_ref (tree array, tree index)
1864 {
1865   bool swapped = false;
1866   if (TREE_TYPE (array) == error_mark_node
1867       || TREE_TYPE (index) == error_mark_node)
1868     return error_mark_node;
1869
1870   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1871       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1872     {
1873       tree temp;
1874       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1875           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1876         {
1877           error ("subscripted value is neither array nor pointer");
1878           return error_mark_node;
1879         }
1880       temp = array;
1881       array = index;
1882       index = temp;
1883       swapped = true;
1884     }
1885
1886   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1887     {
1888       error ("array subscript is not an integer");
1889       return error_mark_node;
1890     }
1891
1892   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1893     {
1894       error ("subscripted value is pointer to function");
1895       return error_mark_node;
1896     }
1897
1898   /* ??? Existing practice has been to warn only when the char
1899      index is syntactically the index, not for char[array].  */
1900   if (!swapped)
1901      warn_array_subscript_with_type_char (index);
1902
1903   /* Apply default promotions *after* noticing character types.  */
1904   index = default_conversion (index);
1905
1906   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1907
1908   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1909     {
1910       tree rval, type;
1911
1912       /* An array that is indexed by a non-constant
1913          cannot be stored in a register; we must be able to do
1914          address arithmetic on its address.
1915          Likewise an array of elements of variable size.  */
1916       if (TREE_CODE (index) != INTEGER_CST
1917           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1918               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1919         {
1920           if (!c_mark_addressable (array))
1921             return error_mark_node;
1922         }
1923       /* An array that is indexed by a constant value which is not within
1924          the array bounds cannot be stored in a register either; because we
1925          would get a crash in store_bit_field/extract_bit_field when trying
1926          to access a non-existent part of the register.  */
1927       if (TREE_CODE (index) == INTEGER_CST
1928           && TYPE_DOMAIN (TREE_TYPE (array))
1929           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1930         {
1931           if (!c_mark_addressable (array))
1932             return error_mark_node;
1933         }
1934
1935       if (pedantic)
1936         {
1937           tree foo = array;
1938           while (TREE_CODE (foo) == COMPONENT_REF)
1939             foo = TREE_OPERAND (foo, 0);
1940           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1941             pedwarn ("ISO C forbids subscripting %<register%> array");
1942           else if (!flag_isoc99 && !lvalue_p (foo))
1943             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1944         }
1945
1946       type = TREE_TYPE (TREE_TYPE (array));
1947       if (TREE_CODE (type) != ARRAY_TYPE)
1948         type = TYPE_MAIN_VARIANT (type);
1949       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1950       /* Array ref is const/volatile if the array elements are
1951          or if the array is.  */
1952       TREE_READONLY (rval)
1953         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1954             | TREE_READONLY (array));
1955       TREE_SIDE_EFFECTS (rval)
1956         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1957             | TREE_SIDE_EFFECTS (array));
1958       TREE_THIS_VOLATILE (rval)
1959         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1960             /* This was added by rms on 16 Nov 91.
1961                It fixes  vol struct foo *a;  a->elts[1]
1962                in an inline function.
1963                Hope it doesn't break something else.  */
1964             | TREE_THIS_VOLATILE (array));
1965       return require_complete_type (fold (rval));
1966     }
1967   else
1968     {
1969       tree ar = default_conversion (array);
1970
1971       if (ar == error_mark_node)
1972         return ar;
1973
1974       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1975       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1976
1977       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1978                                  "array indexing");
1979     }
1980 }
1981 \f
1982 /* Build an external reference to identifier ID.  FUN indicates
1983    whether this will be used for a function call.  LOC is the source
1984    location of the identifier.  */
1985 tree
1986 build_external_ref (tree id, int fun, location_t loc)
1987 {
1988   tree ref;
1989   tree decl = lookup_name (id);
1990
1991   /* In Objective-C, an instance variable (ivar) may be preferred to
1992      whatever lookup_name() found.  */
1993   decl = objc_lookup_ivar (decl, id);
1994
1995   if (decl && decl != error_mark_node)
1996     ref = decl;
1997   else if (fun)
1998     /* Implicit function declaration.  */
1999     ref = implicitly_declare (id);
2000   else if (decl == error_mark_node)
2001     /* Don't complain about something that's already been
2002        complained about.  */
2003     return error_mark_node;
2004   else
2005     {
2006       undeclared_variable (id, loc);
2007       return error_mark_node;
2008     }
2009
2010   if (TREE_TYPE (ref) == error_mark_node)
2011     return error_mark_node;
2012
2013   if (TREE_DEPRECATED (ref))
2014     warn_deprecated_use (ref);
2015
2016   if (!skip_evaluation)
2017     assemble_external (ref);
2018   TREE_USED (ref) = 1;
2019
2020   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2021     {
2022       if (!in_sizeof && !in_typeof)
2023         C_DECL_USED (ref) = 1;
2024       else if (DECL_INITIAL (ref) == 0
2025                && DECL_EXTERNAL (ref)
2026                && !TREE_PUBLIC (ref))
2027         record_maybe_used_decl (ref);
2028     }
2029
2030   if (TREE_CODE (ref) == CONST_DECL)
2031     {
2032       ref = DECL_INITIAL (ref);
2033       TREE_CONSTANT (ref) = 1;
2034       TREE_INVARIANT (ref) = 1;
2035     }
2036   else if (current_function_decl != 0
2037            && !DECL_FILE_SCOPE_P (current_function_decl)
2038            && (TREE_CODE (ref) == VAR_DECL
2039                || TREE_CODE (ref) == PARM_DECL
2040                || TREE_CODE (ref) == FUNCTION_DECL))
2041     {
2042       tree context = decl_function_context (ref);
2043
2044       if (context != 0 && context != current_function_decl)
2045         DECL_NONLOCAL (ref) = 1;
2046     }
2047
2048   return ref;
2049 }
2050
2051 /* Record details of decls possibly used inside sizeof or typeof.  */
2052 struct maybe_used_decl
2053 {
2054   /* The decl.  */
2055   tree decl;
2056   /* The level seen at (in_sizeof + in_typeof).  */
2057   int level;
2058   /* The next one at this level or above, or NULL.  */
2059   struct maybe_used_decl *next;
2060 };
2061
2062 static struct maybe_used_decl *maybe_used_decls;
2063
2064 /* Record that DECL, an undefined static function reference seen
2065    inside sizeof or typeof, might be used if the operand of sizeof is
2066    a VLA type or the operand of typeof is a variably modified
2067    type.  */
2068
2069 static void
2070 record_maybe_used_decl (tree decl)
2071 {
2072   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2073   t->decl = decl;
2074   t->level = in_sizeof + in_typeof;
2075   t->next = maybe_used_decls;
2076   maybe_used_decls = t;
2077 }
2078
2079 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2080    USED is false, just discard them.  If it is true, mark them used
2081    (if no longer inside sizeof or typeof) or move them to the next
2082    level up (if still inside sizeof or typeof).  */
2083
2084 void
2085 pop_maybe_used (bool used)
2086 {
2087   struct maybe_used_decl *p = maybe_used_decls;
2088   int cur_level = in_sizeof + in_typeof;
2089   while (p && p->level > cur_level)
2090     {
2091       if (used)
2092         {
2093           if (cur_level == 0)
2094             C_DECL_USED (p->decl) = 1;
2095           else
2096             p->level = cur_level;
2097         }
2098       p = p->next;
2099     }
2100   if (!used || cur_level == 0)
2101     maybe_used_decls = p;
2102 }
2103
2104 /* Return the result of sizeof applied to EXPR.  */
2105
2106 struct c_expr
2107 c_expr_sizeof_expr (struct c_expr expr)
2108 {
2109   struct c_expr ret;
2110   if (expr.value == error_mark_node)
2111     {
2112       ret.value = error_mark_node;
2113       ret.original_code = ERROR_MARK;
2114       pop_maybe_used (false);
2115     }
2116   else
2117     {
2118       ret.value = c_sizeof (TREE_TYPE (expr.value));
2119       ret.original_code = ERROR_MARK;
2120       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2121     }
2122   return ret;
2123 }
2124
2125 /* Return the result of sizeof applied to T, a structure for the type
2126    name passed to sizeof (rather than the type itself).  */
2127
2128 struct c_expr
2129 c_expr_sizeof_type (struct c_type_name *t)
2130 {
2131   tree type;
2132   struct c_expr ret;
2133   type = groktypename (t);
2134   ret.value = c_sizeof (type);
2135   ret.original_code = ERROR_MARK;
2136   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
2137   return ret;
2138 }
2139
2140 /* Build a function call to function FUNCTION with parameters PARAMS.
2141    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2142    TREE_VALUE of each node is a parameter-expression.
2143    FUNCTION's data type may be a function type or a pointer-to-function.  */
2144
2145 tree
2146 build_function_call (tree function, tree params)
2147 {
2148   tree fntype, fundecl = 0;
2149   tree coerced_params;
2150   tree name = NULL_TREE, result;
2151   tree tem;
2152
2153   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2154   STRIP_TYPE_NOPS (function);
2155
2156   /* Convert anything with function type to a pointer-to-function.  */
2157   if (TREE_CODE (function) == FUNCTION_DECL)
2158     {
2159       /* Implement type-directed function overloading for builtins.
2160          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2161          handle all the type checking.  The result is a complete expression
2162          that implements this function call.  */
2163       tem = resolve_overloaded_builtin (function, params);
2164       if (tem)
2165         return tem;
2166
2167       name = DECL_NAME (function);
2168       fundecl = function;
2169     }
2170   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2171     function = function_to_pointer_conversion (function);
2172
2173   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2174      expressions, like those used for ObjC messenger dispatches.  */
2175   function = objc_rewrite_function_call (function, params);
2176
2177   fntype = TREE_TYPE (function);
2178
2179   if (TREE_CODE (fntype) == ERROR_MARK)
2180     return error_mark_node;
2181
2182   if (!(TREE_CODE (fntype) == POINTER_TYPE
2183         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2184     {
2185       error ("called object %qE is not a function", function);
2186       return error_mark_node;
2187     }
2188
2189   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2190     current_function_returns_abnormally = 1;
2191
2192   /* fntype now gets the type of function pointed to.  */
2193   fntype = TREE_TYPE (fntype);
2194
2195   /* Check that the function is called through a compatible prototype.
2196      If it is not, replace the call by a trap, wrapped up in a compound
2197      expression if necessary.  This has the nice side-effect to prevent
2198      the tree-inliner from generating invalid assignment trees which may
2199      blow up in the RTL expander later.  */
2200   if ((TREE_CODE (function) == NOP_EXPR
2201        || TREE_CODE (function) == CONVERT_EXPR)
2202       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2203       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2204       && !comptypes (fntype, TREE_TYPE (tem)))
2205     {
2206       tree return_type = TREE_TYPE (fntype);
2207       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2208                                        NULL_TREE);
2209
2210       /* This situation leads to run-time undefined behavior.  We can't,
2211          therefore, simply error unless we can prove that all possible
2212          executions of the program must execute the code.  */
2213       warning (0, "function called through a non-compatible type");
2214
2215       /* We can, however, treat "undefined" any way we please.
2216          Call abort to encourage the user to fix the program.  */
2217       inform ("if this code is reached, the program will abort");
2218
2219       if (VOID_TYPE_P (return_type))
2220         return trap;
2221       else
2222         {
2223           tree rhs;
2224
2225           if (AGGREGATE_TYPE_P (return_type))
2226             rhs = build_compound_literal (return_type,
2227                                           build_constructor (return_type, 0));
2228           else
2229             rhs = fold_convert (return_type, integer_zero_node);
2230
2231           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2232         }
2233     }
2234
2235   /* Convert the parameters to the types declared in the
2236      function prototype, or apply default promotions.  */
2237
2238   coerced_params
2239     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2240
2241   if (coerced_params == error_mark_node)
2242     return error_mark_node;
2243
2244   /* Check that the arguments to the function are valid.  */
2245
2246   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2247                             TYPE_ARG_TYPES (fntype));
2248
2249   if (require_constant_value)
2250     {
2251       result = fold_build3_initializer (CALL_EXPR, TREE_TYPE (fntype),
2252                                         function, coerced_params, NULL_TREE);
2253
2254       if (TREE_CONSTANT (result)
2255           && (name == NULL_TREE
2256               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2257         pedwarn_init ("initializer element is not constant");
2258     }
2259   else
2260     result = fold_build3 (CALL_EXPR, TREE_TYPE (fntype),
2261                           function, coerced_params, NULL_TREE);
2262
2263   if (VOID_TYPE_P (TREE_TYPE (result)))
2264     return result;
2265   return require_complete_type (result);
2266 }
2267 \f
2268 /* Convert the argument expressions in the list VALUES
2269    to the types in the list TYPELIST.  The result is a list of converted
2270    argument expressions, unless there are too few arguments in which
2271    case it is error_mark_node.
2272
2273    If TYPELIST is exhausted, or when an element has NULL as its type,
2274    perform the default conversions.
2275
2276    PARMLIST is the chain of parm decls for the function being called.
2277    It may be 0, if that info is not available.
2278    It is used only for generating error messages.
2279
2280    FUNCTION is a tree for the called function.  It is used only for
2281    error messages, where it is formatted with %qE.
2282
2283    This is also where warnings about wrong number of args are generated.
2284
2285    Both VALUES and the returned value are chains of TREE_LIST nodes
2286    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2287
2288 static tree
2289 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2290 {
2291   tree typetail, valtail;
2292   tree result = NULL;
2293   int parmnum;
2294   tree selector;
2295
2296   /* Change pointer to function to the function itself for
2297      diagnostics.  */
2298   if (TREE_CODE (function) == ADDR_EXPR
2299       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2300     function = TREE_OPERAND (function, 0);
2301
2302   /* Handle an ObjC selector specially for diagnostics.  */
2303   selector = objc_message_selector ();
2304
2305   /* Scan the given expressions and types, producing individual
2306      converted arguments and pushing them on RESULT in reverse order.  */
2307
2308   for (valtail = values, typetail = typelist, parmnum = 0;
2309        valtail;
2310        valtail = TREE_CHAIN (valtail), parmnum++)
2311     {
2312       tree type = typetail ? TREE_VALUE (typetail) : 0;
2313       tree val = TREE_VALUE (valtail);
2314       tree rname = function;
2315       int argnum = parmnum + 1;
2316       const char *invalid_func_diag;
2317
2318       if (type == void_type_node)
2319         {
2320           error ("too many arguments to function %qE", function);
2321           break;
2322         }
2323
2324       if (selector && argnum > 2)
2325         {
2326           rname = selector;
2327           argnum -= 2;
2328         }
2329
2330       STRIP_TYPE_NOPS (val);
2331
2332       val = require_complete_type (val);
2333
2334       if (type != 0)
2335         {
2336           /* Formal parm type is specified by a function prototype.  */
2337           tree parmval;
2338
2339           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2340             {
2341               error ("type of formal parameter %d is incomplete", parmnum + 1);
2342               parmval = val;
2343             }
2344           else
2345             {
2346               /* Optionally warn about conversions that
2347                  differ from the default conversions.  */
2348               if (warn_conversion || warn_traditional)
2349                 {
2350                   unsigned int formal_prec = TYPE_PRECISION (type);
2351
2352                   if (INTEGRAL_TYPE_P (type)
2353                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2354                     warning (0, "passing argument %d of %qE as integer "
2355                              "rather than floating due to prototype",
2356                              argnum, rname);
2357                   if (INTEGRAL_TYPE_P (type)
2358                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2359                     warning (0, "passing argument %d of %qE as integer "
2360                              "rather than complex due to prototype",
2361                              argnum, rname);
2362                   else if (TREE_CODE (type) == COMPLEX_TYPE
2363                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2364                     warning (0, "passing argument %d of %qE as complex "
2365                              "rather than floating due to prototype",
2366                              argnum, rname);
2367                   else if (TREE_CODE (type) == REAL_TYPE
2368                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2369                     warning (0, "passing argument %d of %qE as floating "
2370                              "rather than integer due to prototype",
2371                              argnum, rname);
2372                   else if (TREE_CODE (type) == COMPLEX_TYPE
2373                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2374                     warning (0, "passing argument %d of %qE as complex "
2375                              "rather than integer due to prototype",
2376                              argnum, rname);
2377                   else if (TREE_CODE (type) == REAL_TYPE
2378                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2379                     warning (0, "passing argument %d of %qE as floating "
2380                              "rather than complex due to prototype",
2381                              argnum, rname);
2382                   /* ??? At some point, messages should be written about
2383                      conversions between complex types, but that's too messy
2384                      to do now.  */
2385                   else if (TREE_CODE (type) == REAL_TYPE
2386                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2387                     {
2388                       /* Warn if any argument is passed as `float',
2389                          since without a prototype it would be `double'.  */
2390                       if (formal_prec == TYPE_PRECISION (float_type_node)
2391                           && type != dfloat32_type_node)
2392                         warning (0, "passing argument %d of %qE as %<float%> "
2393                                  "rather than %<double%> due to prototype",
2394                                  argnum, rname);
2395
2396                       /* Warn if mismatch between argument and prototype
2397                          for decimal float types.  Warn of conversions with
2398                          binary float types and of precision narrowing due to
2399                          prototype. */
2400                       else if (type != TREE_TYPE (val)
2401                                && (type == dfloat32_type_node
2402                                    || type == dfloat64_type_node
2403                                    || type == dfloat128_type_node
2404                                    || TREE_TYPE (val) == dfloat32_type_node
2405                                    || TREE_TYPE (val) == dfloat64_type_node
2406                                    || TREE_TYPE (val) == dfloat128_type_node)
2407                                && (formal_prec
2408                                    <= TYPE_PRECISION (TREE_TYPE (val))
2409                                    || (type == dfloat128_type_node
2410                                        && (TREE_TYPE (val)
2411                                            != dfloat64_type_node
2412                                            && (TREE_TYPE (val)
2413                                                != dfloat32_type_node)))
2414                                    || (type == dfloat64_type_node
2415                                        && (TREE_TYPE (val)
2416                                            != dfloat32_type_node))))
2417                         warning (0, "passing argument %d of %qE as %qT "
2418                                  "rather than %qT due to prototype",
2419                                  argnum, rname, type, TREE_TYPE (val));
2420
2421                     }
2422                   /* Detect integer changing in width or signedness.
2423                      These warnings are only activated with
2424                      -Wconversion, not with -Wtraditional.  */
2425                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2426                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2427                     {
2428                       tree would_have_been = default_conversion (val);
2429                       tree type1 = TREE_TYPE (would_have_been);
2430
2431                       if (TREE_CODE (type) == ENUMERAL_TYPE
2432                           && (TYPE_MAIN_VARIANT (type)
2433                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2434                         /* No warning if function asks for enum
2435                            and the actual arg is that enum type.  */
2436                         ;
2437                       else if (formal_prec != TYPE_PRECISION (type1))
2438                         warning (OPT_Wconversion, "passing argument %d of %qE "
2439                                  "with different width due to prototype",
2440                                  argnum, rname);
2441                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2442                         ;
2443                       /* Don't complain if the formal parameter type
2444                          is an enum, because we can't tell now whether
2445                          the value was an enum--even the same enum.  */
2446                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2447                         ;
2448                       else if (TREE_CODE (val) == INTEGER_CST
2449                                && int_fits_type_p (val, type))
2450                         /* Change in signedness doesn't matter
2451                            if a constant value is unaffected.  */
2452                         ;
2453                       /* If the value is extended from a narrower
2454                          unsigned type, it doesn't matter whether we
2455                          pass it as signed or unsigned; the value
2456                          certainly is the same either way.  */
2457                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2458                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2459                         ;
2460                       else if (TYPE_UNSIGNED (type))
2461                         warning (OPT_Wconversion, "passing argument %d of %qE "
2462                                  "as unsigned due to prototype",
2463                                  argnum, rname);
2464                       else
2465                         warning (OPT_Wconversion, "passing argument %d of %qE "
2466                                  "as signed due to prototype", argnum, rname);
2467                     }
2468                 }
2469
2470               parmval = convert_for_assignment (type, val, ic_argpass,
2471                                                 fundecl, function,
2472                                                 parmnum + 1);
2473
2474               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2475                   && INTEGRAL_TYPE_P (type)
2476                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2477                 parmval = default_conversion (parmval);
2478             }
2479           result = tree_cons (NULL_TREE, parmval, result);
2480         }
2481       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2482                && (TYPE_PRECISION (TREE_TYPE (val))
2483                    < TYPE_PRECISION (double_type_node))
2484                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2485         /* Convert `float' to `double'.  */
2486         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2487       else if ((invalid_func_diag =
2488                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2489         {
2490           error (invalid_func_diag);
2491           return error_mark_node;
2492         }
2493       else
2494         /* Convert `short' and `char' to full-size `int'.  */
2495         result = tree_cons (NULL_TREE, default_conversion (val), result);
2496
2497       if (typetail)
2498         typetail = TREE_CHAIN (typetail);
2499     }
2500
2501   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2502     {
2503       error ("too few arguments to function %qE", function);
2504       return error_mark_node;
2505     }
2506
2507   return nreverse (result);
2508 }
2509 \f
2510 /* This is the entry point used by the parser to build unary operators
2511    in the input.  CODE, a tree_code, specifies the unary operator, and
2512    ARG is the operand.  For unary plus, the C parser currently uses
2513    CONVERT_EXPR for code.  */
2514
2515 struct c_expr
2516 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2517 {
2518   struct c_expr result;
2519
2520   result.original_code = ERROR_MARK;
2521   result.value = build_unary_op (code, arg.value, 0);
2522   overflow_warning (result.value);
2523   return result;
2524 }
2525
2526 /* This is the entry point used by the parser to build binary operators
2527    in the input.  CODE, a tree_code, specifies the binary operator, and
2528    ARG1 and ARG2 are the operands.  In addition to constructing the
2529    expression, we check for operands that were written with other binary
2530    operators in a way that is likely to confuse the user.  */
2531
2532 struct c_expr
2533 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2534                         struct c_expr arg2)
2535 {
2536   struct c_expr result;
2537
2538   enum tree_code code1 = arg1.original_code;
2539   enum tree_code code2 = arg2.original_code;
2540
2541   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2542   result.original_code = code;
2543
2544   if (TREE_CODE (result.value) == ERROR_MARK)
2545     return result;
2546
2547   /* Check for cases such as x+y<<z which users are likely
2548      to misinterpret.  */
2549   if (warn_parentheses)
2550     {
2551       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2552         {
2553           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2554               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2555             warning (OPT_Wparentheses,
2556                      "suggest parentheses around + or - inside shift");
2557         }
2558
2559       if (code == TRUTH_ORIF_EXPR)
2560         {
2561           if (code1 == TRUTH_ANDIF_EXPR
2562               || code2 == TRUTH_ANDIF_EXPR)
2563             warning (OPT_Wparentheses,
2564                      "suggest parentheses around && within ||");
2565         }
2566
2567       if (code == BIT_IOR_EXPR)
2568         {
2569           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2570               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2571               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2572               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2573             warning (OPT_Wparentheses,
2574                      "suggest parentheses around arithmetic in operand of |");
2575           /* Check cases like x|y==z */
2576           if (TREE_CODE_CLASS (code1) == tcc_comparison
2577               || TREE_CODE_CLASS (code2) == tcc_comparison)
2578             warning (OPT_Wparentheses,
2579                      "suggest parentheses around comparison in operand of |");
2580         }
2581
2582       if (code == BIT_XOR_EXPR)
2583         {
2584           if (code1 == BIT_AND_EXPR
2585               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2586               || code2 == BIT_AND_EXPR
2587               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2588             warning (OPT_Wparentheses,
2589                      "suggest parentheses around arithmetic in operand of ^");
2590           /* Check cases like x^y==z */
2591           if (TREE_CODE_CLASS (code1) == tcc_comparison
2592               || TREE_CODE_CLASS (code2) == tcc_comparison)
2593             warning (OPT_Wparentheses,
2594                      "suggest parentheses around comparison in operand of ^");
2595         }
2596
2597       if (code == BIT_AND_EXPR)
2598         {
2599           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2600               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2601             warning (OPT_Wparentheses,
2602                      "suggest parentheses around + or - in operand of &");
2603           /* Check cases like x&y==z */
2604           if (TREE_CODE_CLASS (code1) == tcc_comparison
2605               || TREE_CODE_CLASS (code2) == tcc_comparison)
2606             warning (OPT_Wparentheses,
2607                      "suggest parentheses around comparison in operand of &");
2608         }
2609       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2610       if (TREE_CODE_CLASS (code) == tcc_comparison
2611           && (TREE_CODE_CLASS (code1) == tcc_comparison
2612               || TREE_CODE_CLASS (code2) == tcc_comparison))
2613         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
2614                  "have their mathematical meaning");
2615
2616     }
2617
2618   /* Warn about comparisons against string literals, with the exception
2619      of testing for equality or inequality of a string literal with NULL.  */
2620   if (code == EQ_EXPR || code == NE_EXPR)
2621     {
2622       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2623           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2624         warning (OPT_Wstring_literal_comparison,
2625                  "comparison with string literal");
2626     }
2627   else if (TREE_CODE_CLASS (code) == tcc_comparison
2628            && (code1 == STRING_CST || code2 == STRING_CST))
2629     warning (OPT_Wstring_literal_comparison,
2630              "comparison with string literal");
2631
2632   unsigned_conversion_warning (result.value, arg1.value);
2633   unsigned_conversion_warning (result.value, arg2.value);
2634   overflow_warning (result.value);
2635
2636   return result;
2637 }
2638 \f
2639 /* Return a tree for the difference of pointers OP0 and OP1.
2640    The resulting tree has type int.  */
2641
2642 static tree
2643 pointer_diff (tree op0, tree op1)
2644 {
2645   tree restype = ptrdiff_type_node;
2646
2647   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2648   tree con0, con1, lit0, lit1;
2649   tree orig_op1 = op1;
2650
2651   if (pedantic || warn_pointer_arith)
2652     {
2653       if (TREE_CODE (target_type) == VOID_TYPE)
2654         pedwarn ("pointer of type %<void *%> used in subtraction");
2655       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2656         pedwarn ("pointer to a function used in subtraction");
2657     }
2658
2659   /* If the conversion to ptrdiff_type does anything like widening or
2660      converting a partial to an integral mode, we get a convert_expression
2661      that is in the way to do any simplifications.
2662      (fold-const.c doesn't know that the extra bits won't be needed.
2663      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2664      different mode in place.)
2665      So first try to find a common term here 'by hand'; we want to cover
2666      at least the cases that occur in legal static initializers.  */
2667   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2668       && (TYPE_PRECISION (TREE_TYPE (op0))
2669           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2670     con0 = TREE_OPERAND (op0, 0);
2671   else
2672     con0 = op0;
2673   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2674       && (TYPE_PRECISION (TREE_TYPE (op1))
2675           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2676     con1 = TREE_OPERAND (op1, 0);
2677   else
2678     con1 = op1;
2679
2680   if (TREE_CODE (con0) == PLUS_EXPR)
2681     {
2682       lit0 = TREE_OPERAND (con0, 1);
2683       con0 = TREE_OPERAND (con0, 0);
2684     }
2685   else
2686     lit0 = integer_zero_node;
2687
2688   if (TREE_CODE (con1) == PLUS_EXPR)
2689     {
2690       lit1 = TREE_OPERAND (con1, 1);
2691       con1 = TREE_OPERAND (con1, 0);
2692     }
2693   else
2694     lit1 = integer_zero_node;
2695
2696   if (operand_equal_p (con0, con1, 0))
2697     {
2698       op0 = lit0;
2699       op1 = lit1;
2700     }
2701
2702
2703   /* First do the subtraction as integers;
2704      then drop through to build the divide operator.
2705      Do not do default conversions on the minus operator
2706      in case restype is a short type.  */
2707
2708   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2709                          convert (restype, op1), 0);
2710   /* This generates an error if op1 is pointer to incomplete type.  */
2711   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2712     error ("arithmetic on pointer to an incomplete type");
2713
2714   /* This generates an error if op0 is pointer to incomplete type.  */
2715   op1 = c_size_in_bytes (target_type);
2716
2717   /* Divide by the size, in easiest possible way.  */
2718   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2719 }
2720 \f
2721 /* Construct and perhaps optimize a tree representation
2722    for a unary operation.  CODE, a tree_code, specifies the operation
2723    and XARG is the operand.
2724    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2725    the default promotions (such as from short to int).
2726    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2727    allows non-lvalues; this is only used to handle conversion of non-lvalue
2728    arrays to pointers in C99.  */
2729
2730 tree
2731 build_unary_op (enum tree_code code, tree xarg, int flag)
2732 {
2733   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2734   tree arg = xarg;
2735   tree argtype = 0;
2736   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2737   tree val;
2738   int noconvert = flag;
2739   const char *invalid_op_diag;
2740
2741   if (typecode == ERROR_MARK)
2742     return error_mark_node;
2743   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2744     typecode = INTEGER_TYPE;
2745
2746   if ((invalid_op_diag
2747        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2748     {
2749       error (invalid_op_diag);
2750       return error_mark_node;
2751     }
2752
2753   switch (code)
2754     {
2755     case CONVERT_EXPR:
2756       /* This is used for unary plus, because a CONVERT_EXPR
2757          is enough to prevent anybody from looking inside for
2758          associativity, but won't generate any code.  */
2759       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2760             || typecode == COMPLEX_TYPE
2761             || typecode == VECTOR_TYPE))
2762         {
2763           error ("wrong type argument to unary plus");
2764           return error_mark_node;
2765         }
2766       else if (!noconvert)
2767         arg = default_conversion (arg);
2768       arg = non_lvalue (arg);
2769       break;
2770
2771     case NEGATE_EXPR:
2772       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2773             || typecode == COMPLEX_TYPE
2774             || typecode == VECTOR_TYPE))
2775         {
2776           error ("wrong type argument to unary minus");
2777           return error_mark_node;
2778         }
2779       else if (!noconvert)
2780         arg = default_conversion (arg);
2781       break;
2782
2783     case BIT_NOT_EXPR:
2784       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2785         {
2786           if (!noconvert)
2787             arg = default_conversion (arg);
2788         }
2789       else if (typecode == COMPLEX_TYPE)
2790         {
2791           code = CONJ_EXPR;
2792           if (pedantic)
2793             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2794           if (!noconvert)
2795             arg = default_conversion (arg);
2796         }
2797       else
2798         {
2799           error ("wrong type argument to bit-complement");
2800           return error_mark_node;
2801         }
2802       break;
2803
2804     case ABS_EXPR:
2805       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2806         {
2807           error ("wrong type argument to abs");
2808           return error_mark_node;
2809         }
2810       else if (!noconvert)
2811         arg = default_conversion (arg);
2812       break;
2813
2814     case CONJ_EXPR:
2815       /* Conjugating a real value is a no-op, but allow it anyway.  */
2816       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2817             || typecode == COMPLEX_TYPE))
2818         {
2819           error ("wrong type argument to conjugation");
2820           return error_mark_node;
2821         }
2822       else if (!noconvert)
2823         arg = default_conversion (arg);
2824       break;
2825
2826     case TRUTH_NOT_EXPR:
2827       if (typecode != INTEGER_TYPE
2828           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2829           && typecode != COMPLEX_TYPE)
2830         {
2831           error ("wrong type argument to unary exclamation mark");
2832           return error_mark_node;
2833         }
2834       arg = c_objc_common_truthvalue_conversion (arg);
2835       return invert_truthvalue (arg);
2836
2837     case REALPART_EXPR:
2838       if (TREE_CODE (arg) == COMPLEX_CST)
2839         return TREE_REALPART (arg);
2840       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2841         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2842       else
2843         return arg;
2844
2845     case IMAGPART_EXPR:
2846       if (TREE_CODE (arg) == COMPLEX_CST)
2847         return TREE_IMAGPART (arg);
2848       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2849         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2850       else
2851         return convert (TREE_TYPE (arg), integer_zero_node);
2852
2853     case PREINCREMENT_EXPR:
2854     case POSTINCREMENT_EXPR:
2855     case PREDECREMENT_EXPR:
2856     case POSTDECREMENT_EXPR:
2857
2858       /* Increment or decrement the real part of the value,
2859          and don't change the imaginary part.  */
2860       if (typecode == COMPLEX_TYPE)
2861         {
2862           tree real, imag;
2863
2864           if (pedantic)
2865             pedwarn ("ISO C does not support %<++%> and %<--%>"
2866                      " on complex types");
2867
2868           arg = stabilize_reference (arg);
2869           real = build_unary_op (REALPART_EXPR, arg, 1);
2870           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2871           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2872                          build_unary_op (code, real, 1), imag);
2873         }
2874
2875       /* Report invalid types.  */
2876
2877       if (typecode != POINTER_TYPE
2878           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2879         {
2880           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2881             error ("wrong type argument to increment");
2882           else
2883             error ("wrong type argument to decrement");
2884
2885           return error_mark_node;
2886         }
2887
2888       {
2889         tree inc;
2890         tree result_type = TREE_TYPE (arg);
2891
2892         arg = get_unwidened (arg, 0);
2893         argtype = TREE_TYPE (arg);
2894
2895         /* Compute the increment.  */
2896
2897         if (typecode == POINTER_TYPE)
2898           {
2899             /* If pointer target is an undefined struct,
2900                we just cannot know how to do the arithmetic.  */
2901             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2902               {
2903                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2904                   error ("increment of pointer to unknown structure");
2905                 else
2906                   error ("decrement of pointer to unknown structure");
2907               }
2908             else if ((pedantic || warn_pointer_arith)
2909                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2910                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2911               {
2912                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2913                   pedwarn ("wrong type argument to increment");
2914                 else
2915                   pedwarn ("wrong type argument to decrement");
2916               }
2917
2918             inc = c_size_in_bytes (TREE_TYPE (result_type));
2919           }
2920         else
2921           inc = integer_one_node;
2922
2923         inc = convert (argtype, inc);
2924
2925         /* Complain about anything else that is not a true lvalue.  */
2926         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2927                                     || code == POSTINCREMENT_EXPR)
2928                                    ? lv_increment
2929                                    : lv_decrement)))
2930           return error_mark_node;
2931
2932         /* Report a read-only lvalue.  */
2933         if (TREE_READONLY (arg))
2934           {
2935             readonly_error (arg,
2936                             ((code == PREINCREMENT_EXPR
2937                               || code == POSTINCREMENT_EXPR)
2938                              ? lv_increment : lv_decrement));
2939             return error_mark_node;
2940           }
2941
2942         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2943           val = boolean_increment (code, arg);
2944         else
2945           val = build2 (code, TREE_TYPE (arg), arg, inc);
2946         TREE_SIDE_EFFECTS (val) = 1;
2947         val = convert (result_type, val);
2948         if (TREE_CODE (val) != code)
2949           TREE_NO_WARNING (val) = 1;
2950         return val;
2951       }
2952
2953     case ADDR_EXPR:
2954       /* Note that this operation never does default_conversion.  */
2955
2956       /* Let &* cancel out to simplify resulting code.  */
2957       if (TREE_CODE (arg) == INDIRECT_REF)
2958         {
2959           /* Don't let this be an lvalue.  */
2960           if (lvalue_p (TREE_OPERAND (arg, 0)))
2961             return non_lvalue (TREE_OPERAND (arg, 0));
2962           return TREE_OPERAND (arg, 0);
2963         }
2964
2965       /* For &x[y], return x+y */
2966       if (TREE_CODE (arg) == ARRAY_REF)
2967         {
2968           tree op0 = TREE_OPERAND (arg, 0);
2969           if (!c_mark_addressable (op0))
2970             return error_mark_node;
2971           return build_binary_op (PLUS_EXPR,
2972                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2973                                    ? array_to_pointer_conversion (op0)
2974                                    : op0),
2975                                   TREE_OPERAND (arg, 1), 1);
2976         }
2977
2978       /* Anything not already handled and not a true memory reference
2979          or a non-lvalue array is an error.  */
2980       else if (typecode != FUNCTION_TYPE && !flag
2981                && !lvalue_or_else (arg, lv_addressof))
2982         return error_mark_node;
2983
2984       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2985       argtype = TREE_TYPE (arg);
2986
2987       /* If the lvalue is const or volatile, merge that into the type
2988          to which the address will point.  Note that you can't get a
2989          restricted pointer by taking the address of something, so we
2990          only have to deal with `const' and `volatile' here.  */
2991       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2992           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2993           argtype = c_build_type_variant (argtype,
2994                                           TREE_READONLY (arg),
2995                                           TREE_THIS_VOLATILE (arg));
2996
2997       if (!c_mark_addressable (arg))
2998         return error_mark_node;
2999
3000       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3001                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3002
3003       argtype = build_pointer_type (argtype);
3004
3005       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3006          when we have proper support for integer constant expressions.  */
3007       val = get_base_address (arg);
3008       if (val && TREE_CODE (val) == INDIRECT_REF
3009           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3010         {
3011           tree op0 = fold_convert (argtype, fold_offsetof (arg)), op1;
3012
3013           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3014           return fold_build2 (PLUS_EXPR, argtype, op0, op1);
3015         }
3016
3017       val = build1 (ADDR_EXPR, argtype, arg);
3018
3019       return val;
3020
3021     default:
3022       gcc_unreachable ();
3023     }
3024
3025   if (argtype == 0)
3026     argtype = TREE_TYPE (arg);
3027   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3028                                 : fold_build1 (code, argtype, arg);
3029 }
3030
3031 /* Return nonzero if REF is an lvalue valid for this language.
3032    Lvalues can be assigned, unless their type has TYPE_READONLY.
3033    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3034
3035 static int
3036 lvalue_p (tree ref)
3037 {
3038   enum tree_code code = TREE_CODE (ref);
3039
3040   switch (code)
3041     {
3042     case REALPART_EXPR:
3043     case IMAGPART_EXPR:
3044     case COMPONENT_REF:
3045       return lvalue_p (TREE_OPERAND (ref, 0));
3046
3047     case COMPOUND_LITERAL_EXPR:
3048     case STRING_CST:
3049       return 1;
3050
3051     case INDIRECT_REF:
3052     case ARRAY_REF:
3053     case VAR_DECL:
3054     case PARM_DECL:
3055     case RESULT_DECL:
3056     case ERROR_MARK:
3057       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3058               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3059
3060     case BIND_EXPR:
3061       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3062
3063     default:
3064       return 0;
3065     }
3066 }
3067 \f
3068 /* Give an error for storing in something that is 'const'.  */
3069
3070 static void
3071 readonly_error (tree arg, enum lvalue_use use)
3072 {
3073   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3074               || use == lv_asm);
3075   /* Using this macro rather than (for example) arrays of messages
3076      ensures that all the format strings are checked at compile
3077      time.  */
3078 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3079                                    : (use == lv_increment ? (I)         \
3080                                    : (use == lv_decrement ? (D) : (AS))))
3081   if (TREE_CODE (arg) == COMPONENT_REF)
3082     {
3083       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3084         readonly_error (TREE_OPERAND (arg, 0), use);
3085       else
3086         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3087                              G_("increment of read-only member %qD"),
3088                              G_("decrement of read-only member %qD"),
3089                              G_("read-only member %qD used as %<asm%> output")),
3090                TREE_OPERAND (arg, 1));
3091     }
3092   else if (TREE_CODE (arg) == VAR_DECL)
3093     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3094                          G_("increment of read-only variable %qD"),
3095                          G_("decrement of read-only variable %qD"),
3096                          G_("read-only variable %qD used as %<asm%> output")),
3097            arg);
3098   else
3099     error (READONLY_MSG (G_("assignment of read-only location"),
3100                          G_("increment of read-only location"),
3101                          G_("decrement of read-only location"),
3102                          G_("read-only location used as %<asm%> output")));
3103 }
3104
3105
3106 /* Return nonzero if REF is an lvalue valid for this language;
3107    otherwise, print an error message and return zero.  USE says
3108    how the lvalue is being used and so selects the error message.  */
3109
3110 static int
3111 lvalue_or_else (tree ref, enum lvalue_use use)
3112 {
3113   int win = lvalue_p (ref);
3114
3115   if (!win)
3116     lvalue_error (use);
3117
3118   return win;
3119 }
3120 \f
3121 /* Mark EXP saying that we need to be able to take the
3122    address of it; it should not be allocated in a register.
3123    Returns true if successful.  */
3124
3125 bool
3126 c_mark_addressable (tree exp)
3127 {
3128   tree x = exp;
3129
3130   while (1)
3131     switch (TREE_CODE (x))
3132       {
3133       case COMPONENT_REF:
3134         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3135           {
3136             error
3137               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3138             return false;
3139           }
3140
3141         /* ... fall through ...  */
3142
3143       case ADDR_EXPR:
3144       case ARRAY_REF:
3145       case REALPART_EXPR:
3146       case IMAGPART_EXPR:
3147         x = TREE_OPERAND (x, 0);
3148         break;
3149
3150       case COMPOUND_LITERAL_EXPR:
3151       case CONSTRUCTOR:
3152         TREE_ADDRESSABLE (x) = 1;
3153         return true;
3154
3155       case VAR_DECL:
3156       case CONST_DECL:
3157       case PARM_DECL:
3158       case RESULT_DECL:
3159         if (C_DECL_REGISTER (x)
3160             && DECL_NONLOCAL (x))
3161           {
3162             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3163               {
3164                 error
3165                   ("global register variable %qD used in nested function", x);
3166                 return false;
3167               }
3168             pedwarn ("register variable %qD used in nested function", x);
3169           }
3170         else if (C_DECL_REGISTER (x))
3171           {
3172             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3173               error ("address of global register variable %qD requested", x);
3174             else
3175               error ("address of register variable %qD requested", x);
3176             return false;
3177           }
3178
3179         /* drops in */
3180       case FUNCTION_DECL:
3181         TREE_ADDRESSABLE (x) = 1;
3182         /* drops out */
3183       default:
3184         return true;
3185     }
3186 }
3187 \f
3188 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3189
3190 tree
3191 build_conditional_expr (tree ifexp, tree op1, tree op2)
3192 {
3193   tree type1;
3194   tree type2;
3195   enum tree_code code1;
3196   enum tree_code code2;
3197   tree result_type = NULL;
3198   tree orig_op1 = op1, orig_op2 = op2;
3199
3200   /* Promote both alternatives.  */
3201
3202   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3203     op1 = default_conversion (op1);
3204   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3205     op2 = default_conversion (op2);
3206
3207   if (TREE_CODE (ifexp) == ERROR_MARK
3208       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3209       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3210     return error_mark_node;
3211
3212   type1 = TREE_TYPE (op1);
3213   code1 = TREE_CODE (type1);
3214   type2 = TREE_TYPE (op2);
3215   code2 = TREE_CODE (type2);
3216
3217   /* C90 does not permit non-lvalue arrays in conditional expressions.
3218      In C99 they will be pointers by now.  */
3219   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3220     {
3221       error ("non-lvalue array in conditional expression");
3222       return error_mark_node;
3223     }
3224
3225   /* Quickly detect the usual case where op1 and op2 have the same type
3226      after promotion.  */
3227   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3228     {
3229       if (type1 == type2)
3230         result_type = type1;
3231       else
3232         result_type = TYPE_MAIN_VARIANT (type1);
3233     }
3234   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3235             || code1 == COMPLEX_TYPE)
3236            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3237                || code2 == COMPLEX_TYPE))
3238     {
3239       result_type = c_common_type (type1, type2);
3240
3241       /* If -Wsign-compare, warn here if type1 and type2 have
3242          different signedness.  We'll promote the signed to unsigned
3243          and later code won't know it used to be different.
3244          Do this check on the original types, so that explicit casts
3245          will be considered, but default promotions won't.  */
3246       if (warn_sign_compare && !skip_evaluation)
3247         {
3248           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3249           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3250
3251           if (unsigned_op1 ^ unsigned_op2)
3252             {
3253               /* Do not warn if the result type is signed, since the
3254                  signed type will only be chosen if it can represent
3255                  all the values of the unsigned type.  */
3256               if (!TYPE_UNSIGNED (result_type))
3257                 /* OK */;
3258               /* Do not warn if the signed quantity is an unsuffixed
3259                  integer literal (or some static constant expression
3260                  involving such literals) and it is non-negative.  */
3261               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3262                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3263                 /* OK */;
3264               else
3265                 warning (0, "signed and unsigned type in conditional expression");
3266             }
3267         }
3268     }
3269   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3270     {
3271       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3272         pedwarn ("ISO C forbids conditional expr with only one void side");
3273       result_type = void_type_node;
3274     }
3275   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3276     {
3277       if (comp_target_types (type1, type2))
3278         result_type = common_pointer_type (type1, type2);
3279       else if (null_pointer_constant_p (orig_op1))
3280         result_type = qualify_type (type2, type1);
3281       else if (null_pointer_constant_p (orig_op2))
3282         result_type = qualify_type (type1, type2);
3283       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3284         {
3285           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3286             pedwarn ("ISO C forbids conditional expr between "
3287                      "%<void *%> and function pointer");
3288           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3289                                                           TREE_TYPE (type2)));
3290         }
3291       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3292         {
3293           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3294             pedwarn ("ISO C forbids conditional expr between "
3295                      "%<void *%> and function pointer");
3296           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3297                                                           TREE_TYPE (type1)));
3298         }
3299       else
3300         {
3301           pedwarn ("pointer type mismatch in conditional expression");
3302           result_type = build_pointer_type (void_type_node);
3303         }
3304     }
3305   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3306     {
3307       if (!null_pointer_constant_p (orig_op2))
3308         pedwarn ("pointer/integer type mismatch in conditional expression");
3309       else
3310         {
3311           op2 = null_pointer_node;
3312         }
3313       result_type = type1;
3314     }
3315   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3316     {
3317       if (!null_pointer_constant_p (orig_op1))
3318         pedwarn ("pointer/integer type mismatch in conditional expression");
3319       else
3320         {
3321           op1 = null_pointer_node;
3322         }
3323       result_type = type2;
3324     }
3325
3326   if (!result_type)
3327     {
3328       if (flag_cond_mismatch)
3329         result_type = void_type_node;
3330       else
3331         {
3332           error ("type mismatch in conditional expression");
3333           return error_mark_node;
3334         }
3335     }
3336
3337   /* Merge const and volatile flags of the incoming types.  */
3338   result_type
3339     = build_type_variant (result_type,
3340                           TREE_READONLY (op1) || TREE_READONLY (op2),
3341                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3342
3343   if (result_type != TREE_TYPE (op1))
3344     op1 = convert_and_check (result_type, op1);
3345   if (result_type != TREE_TYPE (op2))
3346     op2 = convert_and_check (result_type, op2);
3347
3348   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3349 }
3350 \f
3351 /* Return a compound expression that performs two expressions and
3352    returns the value of the second of them.  */
3353
3354 tree
3355 build_compound_expr (tree expr1, tree expr2)
3356 {
3357   if (!TREE_SIDE_EFFECTS (expr1))
3358     {
3359       /* The left-hand operand of a comma expression is like an expression
3360          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3361          any side-effects, unless it was explicitly cast to (void).  */
3362       if (warn_unused_value)
3363         {
3364           if (VOID_TYPE_P (TREE_TYPE (expr1))
3365               && (TREE_CODE (expr1) == NOP_EXPR
3366                   || TREE_CODE (expr1) == CONVERT_EXPR))
3367             ; /* (void) a, b */
3368           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3369                    && TREE_CODE (expr1) == COMPOUND_EXPR
3370                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3371                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
3372             ; /* (void) a, (void) b, c */
3373           else
3374             warning (0, "left-hand operand of comma expression has no effect");
3375         }
3376     }
3377
3378   /* With -Wunused, we should also warn if the left-hand operand does have
3379      side-effects, but computes a value which is not used.  For example, in
3380      `foo() + bar(), baz()' the result of the `+' operator is not used,
3381      so we should issue a warning.  */
3382   else if (warn_unused_value)
3383     warn_if_unused_value (expr1, input_location);
3384
3385   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3386 }
3387
3388 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3389
3390 tree
3391 build_c_cast (tree type, tree expr)
3392 {
3393   tree value = expr;
3394
3395   if (type == error_mark_node || expr == error_mark_node)
3396     return error_mark_node;
3397
3398   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3399      only in <protocol> qualifications.  But when constructing cast expressions,
3400      the protocols do matter and must be kept around.  */
3401   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3402     return build1 (NOP_EXPR, type, expr);
3403
3404   type = TYPE_MAIN_VARIANT (type);
3405
3406   if (TREE_CODE (type) == ARRAY_TYPE)
3407     {
3408       error ("cast specifies array type");
3409       return error_mark_node;
3410     }
3411
3412   if (TREE_CODE (type) == FUNCTION_TYPE)
3413     {
3414       error ("cast specifies function type");
3415       return error_mark_node;
3416     }
3417
3418   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3419     {
3420       if (pedantic)
3421         {
3422           if (TREE_CODE (type) == RECORD_TYPE
3423               || TREE_CODE (type) == UNION_TYPE)
3424             pedwarn ("ISO C forbids casting nonscalar to the same type");
3425         }
3426     }
3427   else if (TREE_CODE (type) == UNION_TYPE)
3428     {
3429       tree field;
3430
3431       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3432         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3433                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3434           break;
3435
3436       if (field)
3437         {
3438           tree t;
3439
3440           if (pedantic)
3441             pedwarn ("ISO C forbids casts to union type");
3442           t = digest_init (type,
3443                            build_constructor_single (type, field, value),
3444                            true, 0);
3445           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3446           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3447           return t;
3448         }
3449       error ("cast to union type from type not present in union");
3450       return error_mark_node;
3451     }
3452   else
3453     {
3454       tree otype, ovalue;
3455
3456       if (type == void_type_node)
3457         return build1 (CONVERT_EXPR, type, value);
3458
3459       otype = TREE_TYPE (value);
3460
3461       /* Optionally warn about potentially worrisome casts.  */
3462
3463       if (warn_cast_qual
3464           && TREE_CODE (type) == POINTER_TYPE
3465           && TREE_CODE (otype) == POINTER_TYPE)
3466         {
3467           tree in_type = type;
3468           tree in_otype = otype;
3469           int added = 0;
3470           int discarded = 0;
3471
3472           /* Check that the qualifiers on IN_TYPE are a superset of
3473              the qualifiers of IN_OTYPE.  The outermost level of
3474              POINTER_TYPE nodes is uninteresting and we stop as soon
3475              as we hit a non-POINTER_TYPE node on either type.  */
3476           do
3477             {
3478               in_otype = TREE_TYPE (in_otype);
3479               in_type = TREE_TYPE (in_type);
3480
3481               /* GNU C allows cv-qualified function types.  'const'
3482                  means the function is very pure, 'volatile' means it
3483                  can't return.  We need to warn when such qualifiers
3484                  are added, not when they're taken away.  */
3485               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3486                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3487                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3488               else
3489                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3490             }
3491           while (TREE_CODE (in_type) == POINTER_TYPE
3492                  && TREE_CODE (in_otype) == POINTER_TYPE);
3493
3494           if (added)
3495             warning (0, "cast adds new qualifiers to function type");
3496
3497           if (discarded)
3498             /* There are qualifiers present in IN_OTYPE that are not
3499                present in IN_TYPE.  */
3500             warning (0, "cast discards qualifiers from pointer target type");
3501         }
3502
3503       /* Warn about possible alignment problems.  */
3504       if (STRICT_ALIGNMENT
3505           && TREE_CODE (type) == POINTER_TYPE
3506           && TREE_CODE (otype) == POINTER_TYPE
3507           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3508           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3509           /* Don't warn about opaque types, where the actual alignment
3510              restriction is unknown.  */
3511           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3512                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3513                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3514           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3515         warning (OPT_Wcast_align,
3516                  "cast increases required alignment of target type");
3517
3518       if (TREE_CODE (type) == INTEGER_TYPE
3519           && TREE_CODE (otype) == POINTER_TYPE
3520           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3521       /* Unlike conversion of integers to pointers, where the
3522          warning is disabled for converting constants because
3523          of cases such as SIG_*, warn about converting constant
3524          pointers to integers. In some cases it may cause unwanted
3525          sign extension, and a warning is appropriate.  */
3526         warning (OPT_Wpointer_to_int_cast,
3527                  "cast from pointer to integer of different size");
3528
3529       if (TREE_CODE (value) == CALL_EXPR
3530           && TREE_CODE (type) != TREE_CODE (otype))
3531         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3532                  "to non-matching type %qT", otype, type);
3533
3534       if (TREE_CODE (type) == POINTER_TYPE
3535           && TREE_CODE (otype) == INTEGER_TYPE
3536           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3537           /* Don't warn about converting any constant.  */
3538           && !TREE_CONSTANT (value))
3539         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3540                  "of different size");
3541
3542       strict_aliasing_warning (otype, type, expr);
3543
3544       /* If pedantic, warn for conversions between function and object
3545          pointer types, except for converting a null pointer constant
3546          to function pointer type.  */
3547       if (pedantic
3548           && TREE_CODE (type) == POINTER_TYPE
3549           && TREE_CODE (otype) == POINTER_TYPE
3550           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3551           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3552         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3553
3554       if (pedantic
3555           && TREE_CODE (type) == POINTER_TYPE
3556           && TREE_CODE (otype) == POINTER_TYPE
3557           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3558           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3559           && !null_pointer_constant_p (value))
3560         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3561
3562       ovalue = value;
3563       value = convert (type, value);
3564
3565       /* Ignore any integer overflow caused by the cast.  */
3566       if (TREE_CODE (value) == INTEGER_CST)
3567         {
3568           if (CONSTANT_CLASS_P (ovalue)
3569               && (TREE_OVERFLOW (ovalue) || TREE_CONSTANT_OVERFLOW (ovalue)))
3570             {
3571               /* Avoid clobbering a shared constant.  */
3572               value = copy_node (value);
3573               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3574               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3575             }
3576           else if (TREE_OVERFLOW (value) || TREE_CONSTANT_OVERFLOW (value))
3577             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3578             value = build_int_cst_wide (TREE_TYPE (value),
3579                                         TREE_INT_CST_LOW (value),
3580                                         TREE_INT_CST_HIGH (value));
3581         }
3582     }
3583
3584   /* Don't let a cast be an lvalue.  */
3585   if (value == expr)
3586     value = non_lvalue (value);
3587
3588   return value;
3589 }
3590
3591 /* Interpret a cast of expression EXPR to type TYPE.  */
3592 tree
3593 c_cast_expr (struct c_type_name *type_name, tree expr)
3594 {
3595   tree type;
3596   int saved_wsp = warn_strict_prototypes;
3597
3598   /* This avoids warnings about unprototyped casts on
3599      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3600   if (TREE_CODE (expr) == INTEGER_CST)
3601     warn_strict_prototypes = 0;
3602   type = groktypename (type_name);
3603   warn_strict_prototypes = saved_wsp;
3604
3605   return build_c_cast (type, expr);
3606 }
3607
3608 \f
3609 /* Build an assignment expression of lvalue LHS from value RHS.
3610    MODIFYCODE is the code for a binary operator that we use
3611    to combine the old value of LHS with RHS to get the new value.
3612    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3613
3614 tree
3615 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3616 {
3617   tree result;
3618   tree newrhs;
3619   tree lhstype = TREE_TYPE (lhs);
3620   tree olhstype = lhstype;
3621
3622   /* Types that aren't fully specified cannot be used in assignments.  */
3623   lhs = require_complete_type (lhs);
3624
3625   /* Avoid duplicate error messages from operands that had errors.  */
3626   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3627     return error_mark_node;
3628
3629   STRIP_TYPE_NOPS (rhs);
3630
3631   newrhs = rhs;
3632
3633   /* If a binary op has been requested, combine the old LHS value with the RHS
3634      producing the value we should actually store into the LHS.  */
3635
3636   if (modifycode != NOP_EXPR)
3637     {
3638       lhs = stabilize_reference (lhs);
3639       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3640     }
3641
3642   if (!lvalue_or_else (lhs, lv_assign))
3643     return error_mark_node;
3644
3645   /* Give an error for storing in something that is 'const'.  */
3646
3647   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3648       || ((TREE_CODE (lhstype) == RECORD_TYPE
3649            || TREE_CODE (lhstype) == UNION_TYPE)
3650           && C_TYPE_FIELDS_READONLY (lhstype)))
3651     {
3652       readonly_error (lhs, lv_assign);
3653       return error_mark_node;
3654     }
3655
3656   /* If storing into a structure or union member,
3657      it has probably been given type `int'.
3658      Compute the type that would go with
3659      the actual amount of storage the member occupies.  */
3660
3661   if (TREE_CODE (lhs) == COMPONENT_REF
3662       && (TREE_CODE (lhstype) == INTEGER_TYPE
3663           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3664           || TREE_CODE (lhstype) == REAL_TYPE
3665           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3666     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3667
3668   /* If storing in a field that is in actuality a short or narrower than one,
3669      we must store in the field in its actual type.  */
3670
3671   if (lhstype != TREE_TYPE (lhs))
3672     {
3673       lhs = copy_node (lhs);
3674       TREE_TYPE (lhs) = lhstype;
3675     }
3676
3677   /* Convert new value to destination type.  */
3678
3679   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3680                                    NULL_TREE, NULL_TREE, 0);
3681   if (TREE_CODE (newrhs) == ERROR_MARK)
3682     return error_mark_node;
3683
3684   /* Emit ObjC write barrier, if necessary.  */
3685   if (c_dialect_objc () && flag_objc_gc)
3686     {
3687       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3688       if (result)
3689         return result;
3690     }
3691
3692   /* Scan operands.  */
3693
3694   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3695   TREE_SIDE_EFFECTS (result) = 1;
3696
3697   /* If we got the LHS in a different type for storing in,
3698      convert the result back to the nominal type of LHS
3699      so that the value we return always has the same type
3700      as the LHS argument.  */
3701
3702   if (olhstype == TREE_TYPE (result))
3703     return result;
3704   return convert_for_assignment (olhstype, result, ic_assign,
3705                                  NULL_TREE, NULL_TREE, 0);
3706 }
3707 \f
3708 /* Convert value RHS to type TYPE as preparation for an assignment
3709    to an lvalue of type TYPE.
3710    The real work of conversion is done by `convert'.
3711    The purpose of this function is to generate error messages
3712    for assignments that are not allowed in C.
3713    ERRTYPE says whether it is argument passing, assignment,
3714    initialization or return.
3715
3716    FUNCTION is a tree for the function being called.
3717    PARMNUM is the number of the argument, for printing in error messages.  */
3718
3719 static tree
3720 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3721                         tree fundecl, tree function, int parmnum)
3722 {
3723   enum tree_code codel = TREE_CODE (type);
3724   tree rhstype;
3725   enum tree_code coder;
3726   tree rname = NULL_TREE;
3727   bool objc_ok = false;
3728
3729   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3730     {
3731       tree selector;
3732       /* Change pointer to function to the function itself for
3733          diagnostics.  */
3734       if (TREE_CODE (function) == ADDR_EXPR
3735           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3736         function = TREE_OPERAND (function, 0);
3737
3738       /* Handle an ObjC selector specially for diagnostics.  */
3739       selector = objc_message_selector ();
3740       rname = function;
3741       if (selector && parmnum > 2)
3742         {
3743           rname = selector;
3744           parmnum -= 2;
3745         }
3746     }
3747
3748   /* This macro is used to emit diagnostics to ensure that all format
3749      strings are complete sentences, visible to gettext and checked at
3750      compile time.  */
3751 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3752   do {                                          \
3753     switch (errtype)                            \
3754       {                                         \
3755       case ic_argpass:                          \
3756         pedwarn (AR, parmnum, rname);           \
3757         break;                                  \
3758       case ic_argpass_nonproto:                 \
3759         warning (0, AR, parmnum, rname);                \
3760         break;                                  \
3761       case ic_assign:                           \
3762         pedwarn (AS);                           \
3763         break;                                  \
3764       case ic_init:                             \
3765         pedwarn (IN);                           \
3766         break;                                  \
3767       case ic_return:                           \
3768         pedwarn (RE);                           \
3769         break;                                  \
3770       default:                                  \
3771         gcc_unreachable ();                     \
3772       }                                         \
3773   } while (0)
3774
3775   STRIP_TYPE_NOPS (rhs);
3776
3777   if (optimize && TREE_CODE (rhs) == VAR_DECL
3778            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3779     rhs = decl_constant_value_for_broken_optimization (rhs);
3780
3781   rhstype = TREE_TYPE (rhs);
3782   coder = TREE_CODE (rhstype);
3783
3784   if (coder == ERROR_MARK)
3785     return error_mark_node;
3786
3787   if (c_dialect_objc ())
3788     {
3789       int parmno;
3790
3791       switch (errtype)
3792         {
3793         case ic_return:
3794           parmno = 0;
3795           break;
3796
3797         case ic_assign:
3798           parmno = -1;
3799           break;
3800
3801         case ic_init:
3802           parmno = -2;
3803           break;
3804
3805         default:
3806           parmno = parmnum;
3807           break;
3808         }
3809
3810       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3811     }
3812
3813   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3814     {
3815       overflow_warning (rhs);
3816       return rhs;
3817     }
3818
3819   if (coder == VOID_TYPE)
3820     {
3821       /* Except for passing an argument to an unprototyped function,
3822          this is a constraint violation.  When passing an argument to
3823          an unprototyped function, it is compile-time undefined;
3824          making it a constraint in that case was rejected in
3825          DR#252.  */
3826       error ("void value not ignored as it ought to be");
3827       return error_mark_node;
3828     }
3829   /* A type converts to a reference to it.
3830      This code doesn't fully support references, it's just for the
3831      special case of va_start and va_copy.  */
3832   if (codel == REFERENCE_TYPE
3833       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3834     {
3835       if (!lvalue_p (rhs))
3836         {
3837           error ("cannot pass rvalue to reference parameter");
3838           return error_mark_node;
3839         }
3840       if (!c_mark_addressable (rhs))
3841         return error_mark_node;
3842       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3843
3844       /* We already know that these two types are compatible, but they
3845          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3846          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3847          likely to be va_list, a typedef to __builtin_va_list, which
3848          is different enough that it will cause problems later.  */
3849       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3850         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3851
3852       rhs = build1 (NOP_EXPR, type, rhs);
3853       return rhs;
3854     }
3855   /* Some types can interconvert without explicit casts.  */
3856   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3857            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3858     return convert (type, rhs);
3859   /* Arithmetic types all interconvert, and enum is treated like int.  */
3860   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3861             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3862             || codel == BOOLEAN_TYPE)
3863            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3864                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3865                || coder == BOOLEAN_TYPE))
3866     return convert_and_check (type, rhs);
3867
3868   /* Conversion to a transparent union from its member types.
3869      This applies only to function arguments.  */
3870   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3871            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3872     {
3873       tree memb, marginal_memb = NULL_TREE;
3874
3875       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3876         {
3877           tree memb_type = TREE_TYPE (memb);
3878
3879           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3880                          TYPE_MAIN_VARIANT (rhstype)))
3881             break;
3882
3883           if (TREE_CODE (memb_type) != POINTER_TYPE)
3884             continue;
3885
3886           if (coder == POINTER_TYPE)
3887             {
3888               tree ttl = TREE_TYPE (memb_type);
3889               tree ttr = TREE_TYPE (rhstype);
3890
3891               /* Any non-function converts to a [const][volatile] void *
3892                  and vice versa; otherwise, targets must be the same.
3893                  Meanwhile, the lhs target must have all the qualifiers of
3894                  the rhs.  */
3895               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3896                   || comp_target_types (memb_type, rhstype))
3897                 {
3898                   /* If this type won't generate any warnings, use it.  */
3899                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3900                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3901                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3902                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3903                              == TYPE_QUALS (ttr))
3904                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3905                              == TYPE_QUALS (ttl))))
3906                     break;
3907
3908                   /* Keep looking for a better type, but remember this one.  */
3909                   if (!marginal_memb)
3910                     marginal_memb = memb;
3911                 }
3912             }
3913
3914           /* Can convert integer zero to any pointer type.  */
3915           if (null_pointer_constant_p (rhs))
3916             {
3917               rhs = null_pointer_node;
3918               break;
3919             }
3920         }
3921
3922       if (memb || marginal_memb)
3923         {
3924           if (!memb)
3925             {
3926               /* We have only a marginally acceptable member type;
3927                  it needs a warning.  */
3928               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3929               tree ttr = TREE_TYPE (rhstype);
3930
3931               /* Const and volatile mean something different for function
3932                  types, so the usual warnings are not appropriate.  */
3933               if (TREE_CODE (ttr) == FUNCTION_TYPE
3934                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3935                 {
3936                   /* Because const and volatile on functions are
3937                      restrictions that say the function will not do
3938                      certain things, it is okay to use a const or volatile
3939                      function where an ordinary one is wanted, but not
3940                      vice-versa.  */
3941                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3942                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3943                                             "makes qualified function "
3944                                             "pointer from unqualified"),
3945                                          G_("assignment makes qualified "
3946                                             "function pointer from "
3947                                             "unqualified"),
3948                                          G_("initialization makes qualified "
3949                                             "function pointer from "
3950                                             "unqualified"),
3951                                          G_("return makes qualified function "
3952                                             "pointer from unqualified"));
3953                 }
3954               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3955                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3956                                         "qualifiers from pointer target type"),
3957                                      G_("assignment discards qualifiers "
3958                                         "from pointer target type"),
3959                                      G_("initialization discards qualifiers "
3960                                         "from pointer target type"),
3961                                      G_("return discards qualifiers from "
3962                                         "pointer target type"));
3963
3964               memb = marginal_memb;
3965             }
3966
3967           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3968             pedwarn ("ISO C prohibits argument conversion to union type");
3969
3970           return build_constructor_single (type, memb, rhs);
3971         }
3972     }
3973
3974   /* Conversions among pointers */
3975   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3976            && (coder == codel))
3977     {
3978       tree ttl = TREE_TYPE (type);
3979       tree ttr = TREE_TYPE (rhstype);
3980       tree mvl = ttl;
3981       tree mvr = ttr;
3982       bool is_opaque_pointer;
3983       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3984
3985       if (TREE_CODE (mvl) != ARRAY_TYPE)
3986         mvl = TYPE_MAIN_VARIANT (mvl);
3987       if (TREE_CODE (mvr) != ARRAY_TYPE)
3988         mvr = TYPE_MAIN_VARIANT (mvr);
3989       /* Opaque pointers are treated like void pointers.  */
3990       is_opaque_pointer = (targetm.vector_opaque_p (type)
3991                            || targetm.vector_opaque_p (rhstype))
3992         && TREE_CODE (ttl) == VECTOR_TYPE
3993         && TREE_CODE (ttr) == VECTOR_TYPE;
3994
3995       /* C++ does not allow the implicit conversion void* -> T*.  However,
3996          for the purpose of reducing the number of false positives, we
3997          tolerate the special case of
3998
3999                 int *p = NULL;
4000
4001          where NULL is typically defined in C to be '(void *) 0'.  */
4002       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4003         warning (OPT_Wc___compat, "request for implicit conversion from "
4004                  "%qT to %qT not permitted in C++", rhstype, type);
4005
4006       /* Check if the right-hand side has a format attribute but the
4007          left-hand side doesn't.  */
4008       if (warn_missing_format_attribute
4009           && check_missing_format_attribute (type, rhstype))
4010         {
4011           switch (errtype)
4012           {
4013           case ic_argpass:
4014           case ic_argpass_nonproto:
4015             warning (OPT_Wmissing_format_attribute,
4016                      "argument %d of %qE might be "
4017                      "a candidate for a format attribute",
4018                      parmnum, rname);
4019             break;
4020           case ic_assign:
4021             warning (OPT_Wmissing_format_attribute,
4022                      "assignment left-hand side might be "
4023                      "a candidate for a format attribute");
4024             break;
4025           case ic_init:
4026             warning (OPT_Wmissing_format_attribute,
4027                      "initialization left-hand side might be "
4028                      "a candidate for a format attribute");
4029             break;
4030           case ic_return:
4031             warning (OPT_Wmissing_format_attribute,
4032                      "return type might be "
4033                      "a candidate for a format attribute");
4034             break;
4035           default:
4036             gcc_unreachable ();
4037           }
4038         }
4039
4040       /* Any non-function converts to a [const][volatile] void *
4041          and vice versa; otherwise, targets must be the same.
4042          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4043       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4044           || (target_cmp = comp_target_types (type, rhstype))
4045           || is_opaque_pointer
4046           || (c_common_unsigned_type (mvl)
4047               == c_common_unsigned_type (mvr)))
4048         {
4049           if (pedantic
4050               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4051                   ||
4052                   (VOID_TYPE_P (ttr)
4053                    && !null_pointer_constant_p (rhs)
4054                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4055             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4056                                     "%qE between function pointer "
4057                                     "and %<void *%>"),
4058                                  G_("ISO C forbids assignment between "
4059                                     "function pointer and %<void *%>"),
4060                                  G_("ISO C forbids initialization between "
4061                                     "function pointer and %<void *%>"),
4062                                  G_("ISO C forbids return between function "
4063                                     "pointer and %<void *%>"));
4064           /* Const and volatile mean something different for function types,
4065              so the usual warnings are not appropriate.  */
4066           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4067                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4068             {
4069               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4070                 {
4071                   /* Types differing only by the presence of the 'volatile'
4072                      qualifier are acceptable if the 'volatile' has been added
4073                      in by the Objective-C EH machinery.  */
4074                   if (!objc_type_quals_match (ttl, ttr))
4075                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4076                                             "qualifiers from pointer target type"),
4077                                          G_("assignment discards qualifiers "
4078                                             "from pointer target type"),
4079                                          G_("initialization discards qualifiers "
4080                                             "from pointer target type"),
4081                                          G_("return discards qualifiers from "
4082                                             "pointer target type"));
4083                 }
4084               /* If this is not a case of ignoring a mismatch in signedness,
4085                  no warning.  */
4086               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4087                        || target_cmp)
4088                 ;
4089               /* If there is a mismatch, do warn.  */
4090               else if (warn_pointer_sign)
4091                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4092                                         "%d of %qE differ in signedness"),
4093                                      G_("pointer targets in assignment "
4094                                         "differ in signedness"),
4095                                      G_("pointer targets in initialization "
4096                                         "differ in signedness"),
4097                                      G_("pointer targets in return differ "
4098                                         "in signedness"));
4099             }
4100           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4101                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4102             {
4103               /* Because const and volatile on functions are restrictions
4104                  that say the function will not do certain things,
4105                  it is okay to use a const or volatile function
4106                  where an ordinary one is wanted, but not vice-versa.  */
4107               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4108                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4109                                         "qualified function pointer "
4110                                         "from unqualified"),
4111                                      G_("assignment makes qualified function "
4112                                         "pointer from unqualified"),
4113                                      G_("initialization makes qualified "
4114                                         "function pointer from unqualified"),
4115                                      G_("return makes qualified function "
4116                                         "pointer from unqualified"));
4117             }
4118         }
4119       else
4120         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4121         if (!objc_ok)
4122           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4123                                   "incompatible pointer type"),
4124                                G_("assignment from incompatible pointer type"),
4125                                G_("initialization from incompatible "
4126                                   "pointer type"),
4127                                G_("return from incompatible pointer type"));
4128
4129       return convert (type, rhs);
4130     }
4131   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4132     {
4133       /* ??? This should not be an error when inlining calls to
4134          unprototyped functions.  */
4135       error ("invalid use of non-lvalue array");
4136       return error_mark_node;
4137     }
4138   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4139     {
4140       /* An explicit constant 0 can convert to a pointer,
4141          or one that results from arithmetic, even including
4142          a cast to integer type.  */
4143       if (!null_pointer_constant_p (rhs))
4144         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4145                                 "pointer from integer without a cast"),
4146                              G_("assignment makes pointer from integer "
4147                                 "without a cast"),
4148                              G_("initialization makes pointer from "
4149                                 "integer without a cast"),
4150                              G_("return makes pointer from integer "
4151                                 "without a cast"));
4152
4153       return convert (type, rhs);
4154     }
4155   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4156     {
4157       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4158                               "from pointer without a cast"),
4159                            G_("assignment makes integer from pointer "
4160                               "without a cast"),
4161                            G_("initialization makes integer from pointer "
4162                               "without a cast"),
4163                            G_("return makes integer from pointer "
4164                               "without a cast"));
4165       return convert (type, rhs);
4166     }
4167   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4168     return convert (type, rhs);
4169
4170   switch (errtype)
4171     {
4172     case ic_argpass:
4173     case ic_argpass_nonproto:
4174       /* ??? This should not be an error when inlining calls to
4175          unprototyped functions.  */
4176       error ("incompatible type for argument %d of %qE", parmnum, rname);
4177       break;
4178     case ic_assign:
4179       error ("incompatible types in assignment");
4180       break;
4181     case ic_init:
4182       error ("incompatible types in initialization");
4183       break;
4184     case ic_return:
4185       error ("incompatible types in return");
4186       break;
4187     default:
4188       gcc_unreachable ();
4189     }
4190
4191   return error_mark_node;
4192 }
4193
4194 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4195    is used for error and waring reporting and indicates which argument
4196    is being processed.  */
4197
4198 tree
4199 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4200 {
4201   tree ret, type;
4202
4203   /* If FN was prototyped, the value has been converted already
4204      in convert_arguments.  */
4205   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4206     return value;
4207
4208   type = TREE_TYPE (parm);
4209   ret = convert_for_assignment (type, value,
4210                                 ic_argpass_nonproto, fn,
4211                                 fn, argnum);
4212   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4213       && INTEGRAL_TYPE_P (type)
4214       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4215     ret = default_conversion (ret);
4216   return ret;
4217 }
4218 \f
4219 /* If VALUE is a compound expr all of whose expressions are constant, then
4220    return its value.  Otherwise, return error_mark_node.
4221
4222    This is for handling COMPOUND_EXPRs as initializer elements
4223    which is allowed with a warning when -pedantic is specified.  */
4224
4225 static tree
4226 valid_compound_expr_initializer (tree value, tree endtype)
4227 {
4228   if (TREE_CODE (value) == COMPOUND_EXPR)
4229     {
4230       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4231           == error_mark_node)
4232         return error_mark_node;
4233       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4234                                               endtype);
4235     }
4236   else if (!initializer_constant_valid_p (value, endtype))
4237     return error_mark_node;
4238   else
4239     return value;
4240 }
4241 \f
4242 /* Perform appropriate conversions on the initial value of a variable,
4243    store it in the declaration DECL,
4244    and print any error messages that are appropriate.
4245    If the init is invalid, store an ERROR_MARK.  */
4246
4247 void
4248 store_init_value (tree decl, tree init)
4249 {
4250   tree value, type;
4251
4252   /* If variable's type was invalidly declared, just ignore it.  */
4253
4254   type = TREE_TYPE (decl);
4255   if (TREE_CODE (type) == ERROR_MARK)
4256     return;
4257
4258   /* Digest the specified initializer into an expression.  */
4259
4260   value = digest_init (type, init, true, TREE_STATIC (decl));
4261
4262   /* Store the expression if valid; else report error.  */
4263
4264   if (!in_system_header
4265       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4266     warning (OPT_Wtraditional, "traditional C rejects automatic "
4267              "aggregate initialization");
4268
4269   DECL_INITIAL (decl) = value;
4270
4271   /* ANSI wants warnings about out-of-range constant initializers.  */
4272   STRIP_TYPE_NOPS (value);
4273   constant_expression_warning (value);
4274
4275   /* Check if we need to set array size from compound literal size.  */
4276   if (TREE_CODE (type) == ARRAY_TYPE
4277       && TYPE_DOMAIN (type) == 0
4278       && value != error_mark_node)
4279     {
4280       tree inside_init = init;
4281
4282       STRIP_TYPE_NOPS (inside_init);
4283       inside_init = fold (inside_init);
4284
4285       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4286         {
4287           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4288
4289           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4290             {
4291               /* For int foo[] = (int [3]){1}; we need to set array size
4292                  now since later on array initializer will be just the
4293                  brace enclosed list of the compound literal.  */
4294               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4295               layout_type (type);
4296               layout_decl (decl, 0);
4297             }
4298         }
4299     }
4300 }
4301 \f
4302 /* Methods for storing and printing names for error messages.  */
4303
4304 /* Implement a spelling stack that allows components of a name to be pushed
4305    and popped.  Each element on the stack is this structure.  */
4306
4307 struct spelling
4308 {
4309   int kind;
4310   union
4311     {
4312       int i;
4313       const char *s;
4314     } u;
4315 };
4316
4317 #define SPELLING_STRING 1
4318 #define SPELLING_MEMBER 2
4319 #define SPELLING_BOUNDS 3
4320
4321 static struct spelling *spelling;       /* Next stack element (unused).  */
4322 static struct spelling *spelling_base;  /* Spelling stack base.  */
4323 static int spelling_size;               /* Size of the spelling stack.  */
4324
4325 /* Macros to save and restore the spelling stack around push_... functions.
4326    Alternative to SAVE_SPELLING_STACK.  */
4327
4328 #define SPELLING_DEPTH() (spelling - spelling_base)
4329 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4330
4331 /* Push an element on the spelling stack with type KIND and assign VALUE
4332    to MEMBER.  */
4333
4334 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4335 {                                                                       \
4336   int depth = SPELLING_DEPTH ();                                        \
4337                                                                         \
4338   if (depth >= spelling_size)                                           \
4339     {                                                                   \
4340       spelling_size += 10;                                              \
4341       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4342                                   spelling_size);                       \
4343       RESTORE_SPELLING_DEPTH (depth);                                   \
4344     }                                                                   \
4345                                                                         \
4346   spelling->kind = (KIND);                                              \
4347   spelling->MEMBER = (VALUE);                                           \
4348   spelling++;                                                           \
4349 }
4350
4351 /* Push STRING on the stack.  Printed literally.  */
4352
4353 static void
4354 push_string (const char *string)
4355 {
4356   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4357 }
4358
4359 /* Push a member name on the stack.  Printed as '.' STRING.  */
4360
4361 static void
4362 push_member_name (tree decl)
4363 {
4364   const char *const string
4365     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4366   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4367 }
4368
4369 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4370
4371 static void
4372 push_array_bounds (int bounds)
4373 {
4374   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4375 }
4376
4377 /* Compute the maximum size in bytes of the printed spelling.  */
4378
4379 static int
4380 spelling_length (void)
4381 {
4382   int size = 0;
4383   struct spelling *p;
4384
4385   for (p = spelling_base; p < spelling; p++)
4386     {
4387       if (p->kind == SPELLING_BOUNDS)
4388         size += 25;
4389       else
4390         size += strlen (p->u.s) + 1;
4391     }
4392
4393   return size;
4394 }
4395
4396 /* Print the spelling to BUFFER and return it.  */
4397
4398 static char *
4399 print_spelling (char *buffer)
4400 {
4401   char *d = buffer;
4402   struct spelling *p;
4403
4404   for (p = spelling_base; p < spelling; p++)
4405     if (p->kind == SPELLING_BOUNDS)
4406       {
4407         sprintf (d, "[%d]", p->u.i);
4408         d += strlen (d);
4409       }
4410     else
4411       {
4412         const char *s;
4413         if (p->kind == SPELLING_MEMBER)
4414           *d++ = '.';
4415         for (s = p->u.s; (*d = *s++); d++)
4416           ;
4417       }
4418   *d++ = '\0';
4419   return buffer;
4420 }
4421
4422 /* Issue an error message for a bad initializer component.
4423    MSGID identifies the message.
4424    The component name is taken from the spelling stack.  */
4425
4426 void
4427 error_init (const char *msgid)
4428 {
4429   char *ofwhat;
4430
4431   error ("%s", _(msgid));
4432   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4433   if (*ofwhat)
4434     error ("(near initialization for %qs)", ofwhat);
4435 }
4436
4437 /* Issue a pedantic warning for a bad initializer component.
4438    MSGID identifies the message.
4439    The component name is taken from the spelling stack.  */
4440
4441 void
4442 pedwarn_init (const char *msgid)
4443 {
4444   char *ofwhat;
4445
4446   pedwarn ("%s", _(msgid));
4447   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4448   if (*ofwhat)
4449     pedwarn ("(near initialization for %qs)", ofwhat);
4450 }
4451
4452 /* Issue a warning for a bad initializer component.
4453    MSGID identifies the message.
4454    The component name is taken from the spelling stack.  */
4455
4456 static void
4457 warning_init (const char *msgid)
4458 {
4459   char *ofwhat;
4460
4461   warning (0, "%s", _(msgid));
4462   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4463   if (*ofwhat)
4464     warning (0, "(near initialization for %qs)", ofwhat);
4465 }
4466 \f
4467 /* If TYPE is an array type and EXPR is a parenthesized string
4468    constant, warn if pedantic that EXPR is being used to initialize an
4469    object of type TYPE.  */
4470
4471 void
4472 maybe_warn_string_init (tree type, struct c_expr expr)
4473 {
4474   if (pedantic
4475       && TREE_CODE (type) == ARRAY_TYPE
4476       && TREE_CODE (expr.value) == STRING_CST
4477       && expr.original_code != STRING_CST)
4478     pedwarn_init ("array initialized from parenthesized string constant");
4479 }
4480
4481 /* Digest the parser output INIT as an initializer for type TYPE.
4482    Return a C expression of type TYPE to represent the initial value.
4483
4484    If INIT is a string constant, STRICT_STRING is true if it is
4485    unparenthesized or we should not warn here for it being parenthesized.
4486    For other types of INIT, STRICT_STRING is not used.
4487
4488    REQUIRE_CONSTANT requests an error if non-constant initializers or
4489    elements are seen.  */
4490
4491 static tree
4492 digest_init (tree type, tree init, bool strict_string, int require_constant)
4493 {
4494   enum tree_code code = TREE_CODE (type);
4495   tree inside_init = init;
4496
4497   if (type == error_mark_node
4498       || init == error_mark_node
4499       || TREE_TYPE (init) == error_mark_node)
4500     return error_mark_node;
4501
4502   STRIP_TYPE_NOPS (inside_init);
4503
4504   inside_init = fold (inside_init);
4505
4506   /* Initialization of an array of chars from a string constant
4507      optionally enclosed in braces.  */
4508
4509   if (code == ARRAY_TYPE && inside_init
4510       && TREE_CODE (inside_init) == STRING_CST)
4511     {
4512       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4513       /* Note that an array could be both an array of character type
4514          and an array of wchar_t if wchar_t is signed char or unsigned
4515          char.  */
4516       bool char_array = (typ1 == char_type_node
4517                          || typ1 == signed_char_type_node
4518                          || typ1 == unsigned_char_type_node);
4519       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4520       if (char_array || wchar_array)
4521         {
4522           struct c_expr expr;
4523           bool char_string;
4524           expr.value = inside_init;
4525           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4526           maybe_warn_string_init (type, expr);
4527
4528           char_string
4529             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4530                == char_type_node);
4531
4532           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4533                          TYPE_MAIN_VARIANT (type)))
4534             return inside_init;
4535
4536           if (!wchar_array && !char_string)
4537             {
4538               error_init ("char-array initialized from wide string");
4539               return error_mark_node;
4540             }
4541           if (char_string && !char_array)
4542             {
4543               error_init ("wchar_t-array initialized from non-wide string");
4544               return error_mark_node;
4545             }
4546
4547           TREE_TYPE (inside_init) = type;
4548           if (TYPE_DOMAIN (type) != 0
4549               && TYPE_SIZE (type) != 0
4550               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4551               /* Subtract 1 (or sizeof (wchar_t))
4552                  because it's ok to ignore the terminating null char
4553                  that is counted in the length of the constant.  */
4554               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4555                                        TREE_STRING_LENGTH (inside_init)
4556                                        - ((TYPE_PRECISION (typ1)
4557                                            != TYPE_PRECISION (char_type_node))
4558                                           ? (TYPE_PRECISION (wchar_type_node)
4559                                              / BITS_PER_UNIT)
4560                                           : 1)))
4561             pedwarn_init ("initializer-string for array of chars is too long");
4562
4563           return inside_init;
4564         }
4565       else if (INTEGRAL_TYPE_P (typ1))
4566         {
4567           error_init ("array of inappropriate type initialized "
4568                       "from string constant");
4569           return error_mark_node;
4570         }
4571     }
4572
4573   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4574      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4575      below and handle as a constructor.  */
4576   if (code == VECTOR_TYPE
4577       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4578       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4579       && TREE_CONSTANT (inside_init))
4580     {
4581       if (TREE_CODE (inside_init) == VECTOR_CST
4582           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4583                         TYPE_MAIN_VARIANT (type)))
4584         return inside_init;
4585
4586       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4587         {
4588           unsigned HOST_WIDE_INT ix;
4589           tree value;
4590           bool constant_p = true;
4591
4592           /* Iterate through elements and check if all constructor
4593              elements are *_CSTs.  */
4594           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4595             if (!CONSTANT_CLASS_P (value))
4596               {
4597                 constant_p = false;
4598                 break;
4599               }
4600
4601           if (constant_p)
4602             return build_vector_from_ctor (type,
4603                                            CONSTRUCTOR_ELTS (inside_init));
4604         }
4605     }
4606
4607   /* Any type can be initialized
4608      from an expression of the same type, optionally with braces.  */
4609
4610   if (inside_init && TREE_TYPE (inside_init) != 0
4611       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4612                      TYPE_MAIN_VARIANT (type))
4613           || (code == ARRAY_TYPE
4614               && comptypes (TREE_TYPE (inside_init), type))
4615           || (code == VECTOR_TYPE
4616               && comptypes (TREE_TYPE (inside_init), type))
4617           || (code == POINTER_TYPE
4618               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4619               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4620                             TREE_TYPE (type)))))
4621     {
4622       if (code == POINTER_TYPE)
4623         {
4624           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4625             {
4626               if (TREE_CODE (inside_init) == STRING_CST
4627                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4628                 inside_init = array_to_pointer_conversion (inside_init);
4629               else
4630                 {
4631                   error_init ("invalid use of non-lvalue array");
4632                   return error_mark_node;
4633                 }
4634             }
4635         }
4636
4637       if (code == VECTOR_TYPE)
4638         /* Although the types are compatible, we may require a
4639            conversion.  */
4640         inside_init = convert (type, inside_init);
4641
4642       if (require_constant && !flag_isoc99
4643           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4644         {
4645           /* As an extension, allow initializing objects with static storage
4646              duration with compound literals (which are then treated just as
4647              the brace enclosed list they contain).  */
4648           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4649           inside_init = DECL_INITIAL (decl);
4650         }
4651
4652       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4653           && TREE_CODE (inside_init) != CONSTRUCTOR)
4654         {
4655           error_init ("array initialized from non-constant array expression");
4656           return error_mark_node;
4657         }
4658
4659       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4660         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4661
4662       /* Compound expressions can only occur here if -pedantic or
4663          -pedantic-errors is specified.  In the later case, we always want
4664          an error.  In the former case, we simply want a warning.  */
4665       if (require_constant && pedantic
4666           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4667         {
4668           inside_init
4669             = valid_compound_expr_initializer (inside_init,
4670                                                TREE_TYPE (inside_init));
4671           if (inside_init == error_mark_node)
4672             error_init ("initializer element is not constant");
4673           else
4674             pedwarn_init ("initializer element is not constant");
4675           if (flag_pedantic_errors)
4676             inside_init = error_mark_node;
4677         }
4678       else if (require_constant
4679                && !initializer_constant_valid_p (inside_init,
4680                                                  TREE_TYPE (inside_init)))
4681         {
4682           error_init ("initializer element is not constant");
4683           inside_init = error_mark_node;
4684         }
4685
4686       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4687       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4688         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4689                                               NULL_TREE, 0);
4690       return inside_init;
4691     }
4692
4693   /* Handle scalar types, including conversions.  */
4694
4695   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4696       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4697       || code == VECTOR_TYPE)
4698     {
4699       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4700           && (TREE_CODE (init) == STRING_CST
4701               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4702         init = array_to_pointer_conversion (init);
4703       inside_init
4704         = convert_for_assignment (type, init, ic_init,
4705                                   NULL_TREE, NULL_TREE, 0);
4706
4707       /* Check to see if we have already given an error message.  */
4708       if (inside_init == error_mark_node)
4709         ;
4710       else if (require_constant && !TREE_CONSTANT (inside_init))
4711         {
4712           error_init ("initializer element is not constant");
4713           inside_init = error_mark_node;
4714         }
4715       else if (require_constant
4716                && !initializer_constant_valid_p (inside_init,
4717                                                  TREE_TYPE (inside_init)))
4718         {
4719           error_init ("initializer element is not computable at load time");
4720           inside_init = error_mark_node;
4721         }
4722
4723       return inside_init;
4724     }
4725
4726   /* Come here only for records and arrays.  */
4727
4728   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4729     {
4730       error_init ("variable-sized object may not be initialized");
4731       return error_mark_node;
4732     }
4733
4734   error_init ("invalid initializer");
4735   return error_mark_node;
4736 }
4737 \f
4738 /* Handle initializers that use braces.  */
4739
4740 /* Type of object we are accumulating a constructor for.
4741    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4742 static tree constructor_type;
4743
4744 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4745    left to fill.  */
4746 static tree constructor_fields;
4747
4748 /* For an ARRAY_TYPE, this is the specified index
4749    at which to store the next element we get.  */
4750 static tree constructor_index;
4751
4752 /* For an ARRAY_TYPE, this is the maximum index.  */
4753 static tree constructor_max_index;
4754
4755 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4756 static tree constructor_unfilled_fields;
4757
4758 /* For an ARRAY_TYPE, this is the index of the first element
4759    not yet written out.  */
4760 static tree constructor_unfilled_index;
4761
4762 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4763    This is so we can generate gaps between fields, when appropriate.  */
4764 static tree constructor_bit_index;
4765
4766 /* If we are saving up the elements rather than allocating them,
4767    this is the list of elements so far (in reverse order,
4768    most recent first).  */
4769 static VEC(constructor_elt,gc) *constructor_elements;
4770
4771 /* 1 if constructor should be incrementally stored into a constructor chain,
4772    0 if all the elements should be kept in AVL tree.  */
4773 static int constructor_incremental;
4774
4775 /* 1 if so far this constructor's elements are all compile-time constants.  */
4776 static int constructor_constant;
4777
4778 /* 1 if so far this constructor's elements are all valid address constants.  */
4779 static int constructor_simple;
4780
4781 /* 1 if this constructor is erroneous so far.  */
4782 static int constructor_erroneous;
4783
4784 /* Structure for managing pending initializer elements, organized as an
4785    AVL tree.  */
4786
4787 struct init_node
4788 {
4789   struct init_node *left, *right;
4790   struct init_node *parent;
4791   int balance;
4792   tree purpose;
4793   tree value;
4794 };
4795
4796 /* Tree of pending elements at this constructor level.
4797    These are elements encountered out of order
4798    which belong at places we haven't reached yet in actually
4799    writing the output.
4800    Will never hold tree nodes across GC runs.  */
4801 static struct init_node *constructor_pending_elts;
4802
4803 /* The SPELLING_DEPTH of this constructor.  */
4804 static int constructor_depth;
4805
4806 /* DECL node for which an initializer is being read.
4807    0 means we are reading a constructor expression
4808    such as (struct foo) {...}.  */
4809 static tree constructor_decl;
4810
4811 /* Nonzero if this is an initializer for a top-level decl.  */
4812 static int constructor_top_level;
4813
4814 /* Nonzero if there were any member designators in this initializer.  */
4815 static int constructor_designated;
4816
4817 /* Nesting depth of designator list.  */
4818 static int designator_depth;
4819
4820 /* Nonzero if there were diagnosed errors in this designator list.  */
4821 static int designator_erroneous;
4822
4823 \f
4824 /* This stack has a level for each implicit or explicit level of
4825    structuring in the initializer, including the outermost one.  It
4826    saves the values of most of the variables above.  */
4827
4828 struct constructor_range_stack;
4829
4830 struct constructor_stack
4831 {
4832   struct constructor_stack *next;
4833   tree type;
4834   tree fields;
4835   tree index;
4836   tree max_index;
4837   tree unfilled_index;
4838   tree unfilled_fields;
4839   tree bit_index;
4840   VEC(constructor_elt,gc) *elements;
4841   struct init_node *pending_elts;
4842   int offset;
4843   int depth;
4844   /* If value nonzero, this value should replace the entire
4845      constructor at this level.  */
4846   struct c_expr replacement_value;
4847   struct constructor_range_stack *range_stack;
4848   char constant;
4849   char simple;
4850   char implicit;
4851   char erroneous;
4852   char outer;
4853   char incremental;
4854   char designated;
4855 };
4856
4857 static struct constructor_stack *constructor_stack;
4858
4859 /* This stack represents designators from some range designator up to
4860    the last designator in the list.  */
4861
4862 struct constructor_range_stack
4863 {
4864   struct constructor_range_stack *next, *prev;
4865   struct constructor_stack *stack;
4866   tree range_start;
4867   tree index;
4868   tree range_end;
4869   tree fields;
4870 };
4871
4872 static struct constructor_range_stack *constructor_range_stack;
4873
4874 /* This stack records separate initializers that are nested.
4875    Nested initializers can't happen in ANSI C, but GNU C allows them
4876    in cases like { ... (struct foo) { ... } ... }.  */
4877
4878 struct initializer_stack
4879 {
4880   struct initializer_stack *next;
4881   tree decl;
4882   struct constructor_stack *constructor_stack;
4883   struct constructor_range_stack *constructor_range_stack;
4884   VEC(constructor_elt,gc) *elements;
4885   struct spelling *spelling;
4886   struct spelling *spelling_base;
4887   int spelling_size;
4888   char top_level;
4889   char require_constant_value;
4890   char require_constant_elements;
4891 };
4892
4893 static struct initializer_stack *initializer_stack;
4894 \f
4895 /* Prepare to parse and output the initializer for variable DECL.  */
4896
4897 void
4898 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4899 {
4900   const char *locus;
4901   struct initializer_stack *p = XNEW (struct initializer_stack);
4902
4903   p->decl = constructor_decl;
4904   p->require_constant_value = require_constant_value;
4905   p->require_constant_elements = require_constant_elements;
4906   p->constructor_stack = constructor_stack;
4907   p->constructor_range_stack = constructor_range_stack;
4908   p->elements = constructor_elements;
4909   p->spelling = spelling;
4910   p->spelling_base = spelling_base;
4911   p->spelling_size = spelling_size;
4912   p->top_level = constructor_top_level;
4913   p->next = initializer_stack;
4914   initializer_stack = p;
4915
4916   constructor_decl = decl;
4917   constructor_designated = 0;
4918   constructor_top_level = top_level;
4919
4920   if (decl != 0 && decl != error_mark_node)
4921     {
4922       require_constant_value = TREE_STATIC (decl);
4923       require_constant_elements
4924         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4925            /* For a scalar, you can always use any value to initialize,
4926               even within braces.  */
4927            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4928                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4929                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4930                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4931       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4932     }
4933   else
4934     {
4935       require_constant_value = 0;
4936       require_constant_elements = 0;
4937       locus = "(anonymous)";
4938     }
4939
4940   constructor_stack = 0;
4941   constructor_range_stack = 0;
4942
4943   missing_braces_mentioned = 0;
4944
4945   spelling_base = 0;
4946   spelling_size = 0;
4947   RESTORE_SPELLING_DEPTH (0);
4948
4949   if (locus)
4950     push_string (locus);
4951 }
4952
4953 void
4954 finish_init (void)
4955 {
4956   struct initializer_stack *p = initializer_stack;
4957
4958   /* Free the whole constructor stack of this initializer.  */
4959   while (constructor_stack)
4960     {
4961       struct constructor_stack *q = constructor_stack;
4962       constructor_stack = q->next;
4963       free (q);
4964     }
4965
4966   gcc_assert (!constructor_range_stack);
4967
4968   /* Pop back to the data of the outer initializer (if any).  */
4969   free (spelling_base);
4970
4971   constructor_decl = p->decl;
4972   require_constant_value = p->require_constant_value;
4973   require_constant_elements = p->require_constant_elements;
4974   constructor_stack = p->constructor_stack;
4975   constructor_range_stack = p->constructor_range_stack;
4976   constructor_elements = p->elements;
4977   spelling = p->spelling;
4978   spelling_base = p->spelling_base;
4979   spelling_size = p->spelling_size;
4980   constructor_top_level = p->top_level;
4981   initializer_stack = p->next;
4982   free (p);
4983 }
4984 \f
4985 /* Call here when we see the initializer is surrounded by braces.
4986    This is instead of a call to push_init_level;
4987    it is matched by a call to pop_init_level.
4988
4989    TYPE is the type to initialize, for a constructor expression.
4990    For an initializer for a decl, TYPE is zero.  */
4991
4992 void
4993 really_start_incremental_init (tree type)
4994 {
4995   struct constructor_stack *p = XNEW (struct constructor_stack);
4996
4997   if (type == 0)
4998     type = TREE_TYPE (constructor_decl);
4999
5000   if (targetm.vector_opaque_p (type))
5001     error ("opaque vector types cannot be initialized");
5002
5003   p->type = constructor_type;
5004   p->fields = constructor_fields;
5005   p->index = constructor_index;
5006   p->max_index = constructor_max_index;
5007   p->unfilled_index = constructor_unfilled_index;
5008   p->unfilled_fields = constructor_unfilled_fields;
5009   p->bit_index = constructor_bit_index;
5010   p->elements = constructor_elements;
5011   p->constant = constructor_constant;
5012   p->simple = constructor_simple;
5013   p->erroneous = constructor_erroneous;
5014   p->pending_elts = constructor_pending_elts;
5015   p->depth = constructor_depth;
5016   p->replacement_value.value = 0;
5017   p->replacement_value.original_code = ERROR_MARK;
5018   p->implicit = 0;
5019   p->range_stack = 0;
5020   p->outer = 0;
5021   p->incremental = constructor_incremental;
5022   p->designated = constructor_designated;
5023   p->next = 0;
5024   constructor_stack = p;
5025
5026   constructor_constant = 1;
5027   constructor_simple = 1;
5028   constructor_depth = SPELLING_DEPTH ();
5029   constructor_elements = 0;
5030   constructor_pending_elts = 0;
5031   constructor_type = type;
5032   constructor_incremental = 1;
5033   constructor_designated = 0;
5034   designator_depth = 0;
5035   designator_erroneous = 0;
5036
5037   if (TREE_CODE (constructor_type) == RECORD_TYPE
5038       || TREE_CODE (constructor_type) == UNION_TYPE)
5039     {
5040       constructor_fields = TYPE_FIELDS (constructor_type);
5041       /* Skip any nameless bit fields at the beginning.  */
5042       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5043              && DECL_NAME (constructor_fields) == 0)
5044         constructor_fields = TREE_CHAIN (constructor_fields);
5045
5046       constructor_unfilled_fields = constructor_fields;
5047       constructor_bit_index = bitsize_zero_node;
5048     }
5049   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5050     {
5051       if (TYPE_DOMAIN (constructor_type))
5052         {
5053           constructor_max_index
5054             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5055
5056           /* Detect non-empty initializations of zero-length arrays.  */
5057           if (constructor_max_index == NULL_TREE
5058               && TYPE_SIZE (constructor_type))
5059             constructor_max_index = build_int_cst (NULL_TREE, -1);
5060
5061           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5062              to initialize VLAs will cause a proper error; avoid tree
5063              checking errors as well by setting a safe value.  */
5064           if (constructor_max_index
5065               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5066             constructor_max_index = build_int_cst (NULL_TREE, -1);
5067
5068           constructor_index
5069             = convert (bitsizetype,
5070                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5071         }
5072       else
5073         {
5074           constructor_index = bitsize_zero_node;
5075           constructor_max_index = NULL_TREE;
5076         }
5077
5078       constructor_unfilled_index = constructor_index;
5079     }
5080   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5081     {
5082       /* Vectors are like simple fixed-size arrays.  */
5083       constructor_max_index =
5084         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5085       constructor_index = convert (bitsizetype, bitsize_zero_node);
5086       constructor_unfilled_index = constructor_index;
5087     }
5088   else
5089     {
5090       /* Handle the case of int x = {5}; */
5091       constructor_fields = constructor_type;
5092       constructor_unfilled_fields = constructor_type;
5093     }
5094 }
5095 \f
5096 /* Push down into a subobject, for initialization.
5097    If this is for an explicit set of braces, IMPLICIT is 0.
5098    If it is because the next element belongs at a lower level,
5099    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5100
5101 void
5102 push_init_level (int implicit)
5103 {
5104   struct constructor_stack *p;
5105   tree value = NULL_TREE;
5106
5107   /* If we've exhausted any levels that didn't have braces,
5108      pop them now.  If implicit == 1, this will have been done in
5109      process_init_element; do not repeat it here because in the case
5110      of excess initializers for an empty aggregate this leads to an
5111      infinite cycle of popping a level and immediately recreating
5112      it.  */
5113   if (implicit != 1)
5114     {
5115       while (constructor_stack->implicit)
5116         {
5117           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5118                || TREE_CODE (constructor_type) == UNION_TYPE)
5119               && constructor_fields == 0)
5120             process_init_element (pop_init_level (1));
5121           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5122                    && constructor_max_index
5123                    && tree_int_cst_lt (constructor_max_index,
5124                                        constructor_index))
5125             process_init_element (pop_init_level (1));
5126           else
5127             break;
5128         }
5129     }
5130
5131   /* Unless this is an explicit brace, we need to preserve previous
5132      content if any.  */
5133   if (implicit)
5134     {
5135       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5136            || TREE_CODE (constructor_type) == UNION_TYPE)
5137           && constructor_fields)
5138         value = find_init_member (constructor_fields);
5139       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5140         value = find_init_member (constructor_index);
5141     }
5142
5143   p = XNEW (struct constructor_stack);
5144   p->type = constructor_type;
5145   p->fields = constructor_fields;
5146   p->index = constructor_index;
5147   p->max_index = constructor_max_index;
5148   p->unfilled_index = constructor_unfilled_index;
5149   p->unfilled_fields = constructor_unfilled_fields;
5150   p->bit_index = constructor_bit_index;
5151   p->elements = constructor_elements;
5152   p->constant = constructor_constant;
5153   p->simple = constructor_simple;
5154   p->erroneous = constructor_erroneous;
5155   p->pending_elts = constructor_pending_elts;
5156   p->depth = constructor_depth;
5157   p->replacement_value.value = 0;
5158   p->replacement_value.original_code = ERROR_MARK;
5159   p->implicit = implicit;
5160   p->outer = 0;
5161   p->incremental = constructor_incremental;
5162   p->designated = constructor_designated;
5163   p->next = constructor_stack;
5164   p->range_stack = 0;
5165   constructor_stack = p;
5166
5167   constructor_constant = 1;
5168   constructor_simple = 1;
5169   constructor_depth = SPELLING_DEPTH ();
5170   constructor_elements = 0;
5171   constructor_incremental = 1;
5172   constructor_designated = 0;
5173   constructor_pending_elts = 0;
5174   if (!implicit)
5175     {
5176       p->range_stack = constructor_range_stack;
5177       constructor_range_stack = 0;
5178       designator_depth = 0;
5179       designator_erroneous = 0;
5180     }
5181
5182   /* Don't die if an entire brace-pair level is superfluous
5183      in the containing level.  */
5184   if (constructor_type == 0)
5185     ;
5186   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5187            || TREE_CODE (constructor_type) == UNION_TYPE)
5188     {
5189       /* Don't die if there are extra init elts at the end.  */
5190       if (constructor_fields == 0)
5191         constructor_type = 0;
5192       else
5193         {
5194           constructor_type = TREE_TYPE (constructor_fields);
5195           push_member_name (constructor_fields);
5196           constructor_depth++;
5197         }
5198     }
5199   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5200     {
5201       constructor_type = TREE_TYPE (constructor_type);
5202       push_array_bounds (tree_low_cst (constructor_index, 0));
5203       constructor_depth++;
5204     }
5205
5206   if (constructor_type == 0)
5207     {
5208       error_init ("extra brace group at end of initializer");
5209       constructor_fields = 0;
5210       constructor_unfilled_fields = 0;
5211       return;
5212     }
5213
5214   if (value && TREE_CODE (value) == CONSTRUCTOR)
5215     {
5216       constructor_constant = TREE_CONSTANT (value);
5217       constructor_simple = TREE_STATIC (value);
5218       constructor_elements = CONSTRUCTOR_ELTS (value);
5219       if (!VEC_empty (constructor_elt, constructor_elements)
5220           && (TREE_CODE (constructor_type) == RECORD_TYPE
5221               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5222         set_nonincremental_init ();
5223     }
5224
5225   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5226     {
5227       missing_braces_mentioned = 1;
5228       warning_init ("missing braces around initializer");
5229     }
5230
5231   if (TREE_CODE (constructor_type) == RECORD_TYPE
5232            || TREE_CODE (constructor_type) == UNION_TYPE)
5233     {
5234       constructor_fields = TYPE_FIELDS (constructor_type);
5235       /* Skip any nameless bit fields at the beginning.  */
5236       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5237              && DECL_NAME (constructor_fields) == 0)
5238         constructor_fields = TREE_CHAIN (constructor_fields);
5239
5240       constructor_unfilled_fields = constructor_fields;
5241       constructor_bit_index = bitsize_zero_node;
5242     }
5243   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5244     {
5245       /* Vectors are like simple fixed-size arrays.  */
5246       constructor_max_index =
5247         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5248       constructor_index = convert (bitsizetype, integer_zero_node);
5249       constructor_unfilled_index = constructor_index;
5250     }
5251   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5252     {
5253       if (TYPE_DOMAIN (constructor_type))
5254         {
5255           constructor_max_index
5256             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5257
5258           /* Detect non-empty initializations of zero-length arrays.  */
5259           if (constructor_max_index == NULL_TREE
5260               && TYPE_SIZE (constructor_type))
5261             constructor_max_index = build_int_cst (NULL_TREE, -1);
5262
5263           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5264              to initialize VLAs will cause a proper error; avoid tree
5265              checking errors as well by setting a safe value.  */
5266           if (constructor_max_index
5267               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5268             constructor_max_index = build_int_cst (NULL_TREE, -1);
5269
5270           constructor_index
5271             = convert (bitsizetype,
5272                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5273         }
5274       else
5275         constructor_index = bitsize_zero_node;
5276
5277       constructor_unfilled_index = constructor_index;
5278       if (value && TREE_CODE (value) == STRING_CST)
5279         {
5280           /* We need to split the char/wchar array into individual
5281              characters, so that we don't have to special case it
5282              everywhere.  */
5283           set_nonincremental_init_from_string (value);
5284         }
5285     }
5286   else
5287     {
5288       if (constructor_type != error_mark_node)
5289         warning_init ("braces around scalar initializer");
5290       constructor_fields = constructor_type;
5291       constructor_unfilled_fields = constructor_type;
5292     }
5293 }
5294
5295 /* At the end of an implicit or explicit brace level,
5296    finish up that level of constructor.  If a single expression
5297    with redundant braces initialized that level, return the
5298    c_expr structure for that expression.  Otherwise, the original_code
5299    element is set to ERROR_MARK.
5300    If we were outputting the elements as they are read, return 0 as the value
5301    from inner levels (process_init_element ignores that),
5302    but return error_mark_node as the value from the outermost level
5303    (that's what we want to put in DECL_INITIAL).
5304    Otherwise, return a CONSTRUCTOR expression as the value.  */
5305
5306 struct c_expr
5307 pop_init_level (int implicit)
5308 {
5309   struct constructor_stack *p;
5310   struct c_expr ret;
5311   ret.value = 0;
5312   ret.original_code = ERROR_MARK;
5313
5314   if (implicit == 0)
5315     {
5316       /* When we come to an explicit close brace,
5317          pop any inner levels that didn't have explicit braces.  */
5318       while (constructor_stack->implicit)
5319         process_init_element (pop_init_level (1));
5320
5321       gcc_assert (!constructor_range_stack);
5322     }
5323
5324   /* Now output all pending elements.  */
5325   constructor_incremental = 1;
5326   output_pending_init_elements (1);
5327
5328   p = constructor_stack;
5329
5330   /* Error for initializing a flexible array member, or a zero-length
5331      array member in an inappropriate context.  */
5332   if (constructor_type && constructor_fields
5333       && TREE_CODE (constructor_type) == ARRAY_TYPE
5334       && TYPE_DOMAIN (constructor_type)
5335       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5336     {
5337       /* Silently discard empty initializations.  The parser will
5338          already have pedwarned for empty brackets.  */
5339       if (integer_zerop (constructor_unfilled_index))
5340         constructor_type = NULL_TREE;
5341       else
5342         {
5343           gcc_assert (!TYPE_SIZE (constructor_type));
5344
5345           if (constructor_depth > 2)
5346             error_init ("initialization of flexible array member in a nested context");
5347           else if (pedantic)
5348             pedwarn_init ("initialization of a flexible array member");
5349
5350           /* We have already issued an error message for the existence
5351              of a flexible array member not at the end of the structure.
5352              Discard the initializer so that we do not die later.  */
5353           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5354             constructor_type = NULL_TREE;
5355         }
5356     }
5357
5358   /* Warn when some struct elements are implicitly initialized to zero.  */
5359   if (warn_missing_field_initializers
5360       && constructor_type
5361       && TREE_CODE (constructor_type) == RECORD_TYPE
5362       && constructor_unfilled_fields)
5363     {
5364         /* Do not warn for flexible array members or zero-length arrays.  */
5365         while (constructor_unfilled_fields
5366                && (!DECL_SIZE (constructor_unfilled_fields)
5367                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5368           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5369
5370         /* Do not warn if this level of the initializer uses member
5371            designators; it is likely to be deliberate.  */
5372         if (constructor_unfilled_fields && !constructor_designated)
5373           {
5374             push_member_name (constructor_unfilled_fields);
5375             warning_init ("missing initializer");
5376             RESTORE_SPELLING_DEPTH (constructor_depth);
5377           }
5378     }
5379
5380   /* Pad out the end of the structure.  */
5381   if (p->replacement_value.value)
5382     /* If this closes a superfluous brace pair,
5383        just pass out the element between them.  */
5384     ret = p->replacement_value;
5385   else if (constructor_type == 0)
5386     ;
5387   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5388            && TREE_CODE (constructor_type) != UNION_TYPE
5389            && TREE_CODE (constructor_type) != ARRAY_TYPE
5390            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5391     {
5392       /* A nonincremental scalar initializer--just return
5393          the element, after verifying there is just one.  */
5394       if (VEC_empty (constructor_elt,constructor_elements))
5395         {
5396           if (!constructor_erroneous)
5397             error_init ("empty scalar initializer");
5398           ret.value = error_mark_node;
5399         }
5400       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5401         {
5402           error_init ("extra elements in scalar initializer");
5403           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5404         }
5405       else
5406         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5407     }
5408   else
5409     {
5410       if (constructor_erroneous)
5411         ret.value = error_mark_node;
5412       else
5413         {
5414           ret.value = build_constructor (constructor_type,
5415                                          constructor_elements);
5416           if (constructor_constant)
5417             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5418           if (constructor_constant && constructor_simple)
5419             TREE_STATIC (ret.value) = 1;
5420         }
5421     }
5422
5423   constructor_type = p->type;
5424   constructor_fields = p->fields;
5425   constructor_index = p->index;
5426   constructor_max_index = p->max_index;
5427   constructor_unfilled_index = p->unfilled_index;
5428   constructor_unfilled_fields = p->unfilled_fields;
5429   constructor_bit_index = p->bit_index;
5430   constructor_elements = p->elements;
5431   constructor_constant = p->constant;
5432   constructor_simple = p->simple;
5433   constructor_erroneous = p->erroneous;
5434   constructor_incremental = p->incremental;
5435   constructor_designated = p->designated;
5436   constructor_pending_elts = p->pending_elts;
5437   constructor_depth = p->depth;
5438   if (!p->implicit)
5439     constructor_range_stack = p->range_stack;
5440   RESTORE_SPELLING_DEPTH (constructor_depth);
5441
5442   constructor_stack = p->next;
5443   free (p);
5444
5445   if (ret.value == 0)
5446     {
5447       if (constructor_stack == 0)
5448         {
5449           ret.value = error_mark_node;
5450           return ret;
5451         }
5452       return ret;
5453     }
5454   return ret;
5455 }
5456
5457 /* Common handling for both array range and field name designators.
5458    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5459
5460 static int
5461 set_designator (int array)
5462 {
5463   tree subtype;
5464   enum tree_code subcode;
5465
5466   /* Don't die if an entire brace-pair level is superfluous
5467      in the containing level.  */
5468   if (constructor_type == 0)
5469     return 1;
5470
5471   /* If there were errors in this designator list already, bail out
5472      silently.  */
5473   if (designator_erroneous)
5474     return 1;
5475
5476   if (!designator_depth)
5477     {
5478       gcc_assert (!constructor_range_stack);
5479
5480       /* Designator list starts at the level of closest explicit
5481          braces.  */
5482       while (constructor_stack->implicit)
5483         process_init_element (pop_init_level (1));
5484       constructor_designated = 1;
5485       return 0;
5486     }
5487
5488   switch (TREE_CODE (constructor_type))
5489     {
5490     case  RECORD_TYPE:
5491     case  UNION_TYPE:
5492       subtype = TREE_TYPE (constructor_fields);
5493       if (subtype != error_mark_node)
5494         subtype = TYPE_MAIN_VARIANT (subtype);
5495       break;
5496     case ARRAY_TYPE:
5497       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5498       break;
5499     default:
5500       gcc_unreachable ();
5501     }
5502
5503   subcode = TREE_CODE (subtype);
5504   if (array && subcode != ARRAY_TYPE)
5505     {
5506       error_init ("array index in non-array initializer");
5507       return 1;
5508     }
5509   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5510     {
5511       error_init ("field name not in record or union initializer");
5512       return 1;
5513     }
5514
5515   constructor_designated = 1;
5516   push_init_level (2);
5517   return 0;
5518 }
5519
5520 /* If there are range designators in designator list, push a new designator
5521    to constructor_range_stack.  RANGE_END is end of such stack range or
5522    NULL_TREE if there is no range designator at this level.  */
5523
5524 static void
5525 push_range_stack (tree range_end)
5526 {
5527   struct constructor_range_stack *p;
5528
5529   p = GGC_NEW (struct constructor_range_stack);
5530   p->prev = constructor_range_stack;
5531   p->next = 0;
5532   p->fields = constructor_fields;
5533   p->range_start = constructor_index;
5534   p->index = constructor_index;
5535   p->stack = constructor_stack;
5536   p->range_end = range_end;
5537   if (constructor_range_stack)
5538     constructor_range_stack->next = p;
5539   constructor_range_stack = p;
5540 }
5541
5542 /* Within an array initializer, specify the next index to be initialized.
5543    FIRST is that index.  If LAST is nonzero, then initialize a range
5544    of indices, running from FIRST through LAST.  */
5545
5546 void
5547 set_init_index (tree first, tree last)
5548 {
5549   if (set_designator (1))
5550     return;
5551
5552   designator_erroneous = 1;
5553
5554   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5555       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5556     {
5557       error_init ("array index in initializer not of integer type");
5558       return;
5559     }
5560
5561   if (TREE_CODE (first) != INTEGER_CST)
5562     error_init ("nonconstant array index in initializer");
5563   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5564     error_init ("nonconstant array index in initializer");
5565   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5566     error_init ("array index in non-array initializer");
5567   else if (tree_int_cst_sgn (first) == -1)
5568     error_init ("array index in initializer exceeds array bounds");
5569   else if (constructor_max_index
5570            && tree_int_cst_lt (constructor_max_index, first))
5571     error_init ("array index in initializer exceeds array bounds");
5572   else
5573     {
5574       constructor_index = convert (bitsizetype, first);
5575
5576       if (last)
5577         {
5578           if (tree_int_cst_equal (first, last))
5579             last = 0;
5580           else if (tree_int_cst_lt (last, first))
5581             {
5582               error_init ("empty index range in initializer");
5583               last = 0;
5584             }
5585           else
5586             {
5587               last = convert (bitsizetype, last);
5588               if (constructor_max_index != 0
5589                   && tree_int_cst_lt (constructor_max_index, last))
5590                 {
5591                   error_init ("array index range in initializer exceeds array bounds");
5592                   last = 0;
5593                 }
5594             }
5595         }
5596
5597       designator_depth++;
5598       designator_erroneous = 0;
5599       if (constructor_range_stack || last)
5600         push_range_stack (last);
5601     }
5602 }
5603
5604 /* Within a struct initializer, specify the next field to be initialized.  */
5605
5606 void
5607 set_init_label (tree fieldname)
5608 {
5609   tree tail;
5610
5611   if (set_designator (0))
5612     return;
5613
5614   designator_erroneous = 1;
5615
5616   if (TREE_CODE (constructor_type) != RECORD_TYPE
5617       && TREE_CODE (constructor_type) != UNION_TYPE)
5618     {
5619       error_init ("field name not in record or union initializer");
5620       return;
5621     }
5622
5623   for (tail = TYPE_FIELDS (constructor_type); tail;
5624        tail = TREE_CHAIN (tail))
5625     {
5626       if (DECL_NAME (tail) == fieldname)
5627         break;
5628     }
5629
5630   if (tail == 0)
5631     error ("unknown field %qE specified in initializer", fieldname);
5632   else
5633     {
5634       constructor_fields = tail;
5635       designator_depth++;
5636       designator_erroneous = 0;
5637       if (constructor_range_stack)
5638         push_range_stack (NULL_TREE);
5639     }
5640 }
5641 \f
5642 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5643    identifies the initializer, either array index or field in a structure.
5644    VALUE is the value of that index or field.  */
5645
5646 static void
5647 add_pending_init (tree purpose, tree value)
5648 {
5649   struct init_node *p, **q, *r;
5650
5651   q = &constructor_pending_elts;
5652   p = 0;
5653
5654   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5655     {
5656       while (*q != 0)
5657         {
5658           p = *q;
5659           if (tree_int_cst_lt (purpose, p->purpose))
5660             q = &p->left;
5661           else if (tree_int_cst_lt (p->purpose, purpose))
5662             q = &p->right;
5663           else
5664             {
5665               if (TREE_SIDE_EFFECTS (p->value))
5666                 warning_init ("initialized field with side-effects overwritten");
5667               p->value = value;
5668               return;
5669             }
5670         }
5671     }
5672   else
5673     {
5674       tree bitpos;
5675
5676       bitpos = bit_position (purpose);
5677       while (*q != NULL)
5678         {
5679           p = *q;
5680           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5681             q = &p->left;
5682           else if (p->purpose != purpose)
5683             q = &p->right;
5684           else
5685             {
5686               if (TREE_SIDE_EFFECTS (p->value))
5687                 warning_init ("initialized field with side-effects overwritten");
5688               p->value = value;
5689               return;
5690             }
5691         }
5692     }
5693
5694   r = GGC_NEW (struct init_node);
5695   r->purpose = purpose;
5696   r->value = value;
5697
5698   *q = r;
5699   r->parent = p;
5700   r->left = 0;
5701   r->right = 0;
5702   r->balance = 0;
5703
5704   while (p)
5705     {
5706       struct init_node *s;
5707
5708       if (r == p->left)
5709         {
5710           if (p->balance == 0)
5711             p->balance = -1;
5712           else if (p->balance < 0)
5713             {
5714               if (r->balance < 0)
5715                 {
5716                   /* L rotation.  */
5717                   p->left = r->right;
5718                   if (p->left)
5719                     p->left->parent = p;
5720                   r->right = p;
5721
5722                   p->balance = 0;
5723                   r->balance = 0;
5724
5725                   s = p->parent;
5726                   p->parent = r;
5727                   r->parent = s;
5728                   if (s)
5729                     {
5730                       if (s->left == p)
5731                         s->left = r;
5732                       else
5733                         s->right = r;
5734                     }
5735                   else
5736                     constructor_pending_elts = r;
5737                 }
5738               else
5739                 {
5740                   /* LR rotation.  */
5741                   struct init_node *t = r->right;
5742
5743                   r->right = t->left;
5744                   if (r->right)
5745                     r->right->parent = r;
5746                   t->left = r;
5747
5748                   p->left = t->right;
5749                   if (p->left)
5750                     p->left->parent = p;
5751                   t->right = p;
5752
5753                   p->balance = t->balance < 0;
5754                   r->balance = -(t->balance > 0);
5755                   t->balance = 0;
5756
5757                   s = p->parent;
5758                   p->parent = t;
5759                   r->parent = t;
5760                   t->parent = s;
5761                   if (s)
5762                     {
5763                       if (s->left == p)
5764                         s->left = t;
5765                       else
5766                         s->right = t;
5767                     }
5768                   else
5769                     constructor_pending_elts = t;
5770                 }
5771               break;
5772             }
5773           else
5774             {
5775               /* p->balance == +1; growth of left side balances the node.  */
5776               p->balance = 0;
5777               break;
5778             }
5779         }
5780       else /* r == p->right */
5781         {
5782           if (p->balance == 0)
5783             /* Growth propagation from right side.  */
5784             p->balance++;
5785           else if (p->balance > 0)
5786             {
5787               if (r->balance > 0)
5788                 {
5789                   /* R rotation.  */
5790                   p->right = r->left;
5791                   if (p->right)
5792                     p->right->parent = p;
5793                   r->left = p;
5794
5795                   p->balance = 0;
5796                   r->balance = 0;
5797
5798                   s = p->parent;
5799                   p->parent = r;
5800                   r->parent = s;
5801                   if (s)
5802                     {
5803                       if (s->left == p)
5804                         s->left = r;
5805                       else
5806                         s->right = r;
5807                     }
5808                   else
5809                     constructor_pending_elts = r;
5810                 }
5811               else /* r->balance == -1 */
5812                 {
5813                   /* RL rotation */
5814                   struct init_node *t = r->left;
5815
5816                   r->left = t->right;
5817                   if (r->left)
5818                     r->left->parent = r;
5819                   t->right = r;
5820
5821                   p->right = t->left;
5822                   if (p->right)
5823                     p->right->parent = p;
5824                   t->left = p;
5825
5826                   r->balance = (t->balance < 0);
5827                   p->balance = -(t->balance > 0);
5828                   t->balance = 0;
5829
5830                   s = p->parent;
5831                   p->parent = t;
5832                   r->parent = t;
5833                   t->parent = s;
5834                   if (s)
5835                     {
5836                       if (s->left == p)
5837                         s->left = t;
5838                       else
5839                         s->right = t;
5840                     }
5841                   else
5842                     constructor_pending_elts = t;
5843                 }
5844               break;
5845             }
5846           else
5847             {
5848               /* p->balance == -1; growth of right side balances the node.  */
5849               p->balance = 0;
5850               break;
5851             }
5852         }
5853
5854       r = p;
5855       p = p->parent;
5856     }
5857 }
5858
5859 /* Build AVL tree from a sorted chain.  */
5860
5861 static void
5862 set_nonincremental_init (void)
5863 {
5864   unsigned HOST_WIDE_INT ix;
5865   tree index, value;
5866
5867   if (TREE_CODE (constructor_type) != RECORD_TYPE
5868       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5869     return;
5870
5871   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5872     add_pending_init (index, value);
5873   constructor_elements = 0;
5874   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5875     {
5876       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5877       /* Skip any nameless bit fields at the beginning.  */
5878       while (constructor_unfilled_fields != 0
5879              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5880              && DECL_NAME (constructor_unfilled_fields) == 0)
5881         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5882
5883     }
5884   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5885     {
5886       if (TYPE_DOMAIN (constructor_type))
5887         constructor_unfilled_index
5888             = convert (bitsizetype,
5889                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5890       else
5891         constructor_unfilled_index = bitsize_zero_node;
5892     }
5893   constructor_incremental = 0;
5894 }
5895
5896 /* Build AVL tree from a string constant.  */
5897
5898 static void
5899 set_nonincremental_init_from_string (tree str)
5900 {
5901   tree value, purpose, type;
5902   HOST_WIDE_INT val[2];
5903   const char *p, *end;
5904   int byte, wchar_bytes, charwidth, bitpos;
5905
5906   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5907
5908   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5909       == TYPE_PRECISION (char_type_node))
5910     wchar_bytes = 1;
5911   else
5912     {
5913       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5914                   == TYPE_PRECISION (wchar_type_node));
5915       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5916     }
5917   charwidth = TYPE_PRECISION (char_type_node);
5918   type = TREE_TYPE (constructor_type);
5919   p = TREE_STRING_POINTER (str);
5920   end = p + TREE_STRING_LENGTH (str);
5921
5922   for (purpose = bitsize_zero_node;
5923        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5924        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5925     {
5926       if (wchar_bytes == 1)
5927         {
5928           val[1] = (unsigned char) *p++;
5929           val[0] = 0;
5930         }
5931       else
5932         {
5933           val[0] = 0;
5934           val[1] = 0;
5935           for (byte = 0; byte < wchar_bytes; byte++)
5936             {
5937               if (BYTES_BIG_ENDIAN)
5938                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5939               else
5940                 bitpos = byte * charwidth;
5941               val[bitpos < HOST_BITS_PER_WIDE_INT]
5942                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5943                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5944             }
5945         }
5946
5947       if (!TYPE_UNSIGNED (type))
5948         {
5949           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5950           if (bitpos < HOST_BITS_PER_WIDE_INT)
5951             {
5952               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5953                 {
5954                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5955                   val[0] = -1;
5956                 }
5957             }
5958           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5959             {
5960               if (val[1] < 0)
5961                 val[0] = -1;
5962             }
5963           else if (val[0] & (((HOST_WIDE_INT) 1)
5964                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5965             val[0] |= ((HOST_WIDE_INT) -1)
5966                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5967         }
5968
5969       value = build_int_cst_wide (type, val[1], val[0]);
5970       add_pending_init (purpose, value);
5971     }
5972
5973   constructor_incremental = 0;
5974 }
5975
5976 /* Return value of FIELD in pending initializer or zero if the field was
5977    not initialized yet.  */
5978
5979 static tree
5980 find_init_member (tree field)
5981 {
5982   struct init_node *p;
5983
5984   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5985     {
5986       if (constructor_incremental
5987           && tree_int_cst_lt (field, constructor_unfilled_index))
5988         set_nonincremental_init ();
5989
5990       p = constructor_pending_elts;
5991       while (p)
5992         {
5993           if (tree_int_cst_lt (field, p->purpose))
5994             p = p->left;
5995           else if (tree_int_cst_lt (p->purpose, field))
5996             p = p->right;
5997           else
5998             return p->value;
5999         }
6000     }
6001   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6002     {
6003       tree bitpos = bit_position (field);
6004
6005       if (constructor_incremental
6006           && (!constructor_unfilled_fields
6007               || tree_int_cst_lt (bitpos,
6008                                   bit_position (constructor_unfilled_fields))))
6009         set_nonincremental_init ();
6010
6011       p = constructor_pending_elts;
6012       while (p)
6013         {
6014           if (field == p->purpose)
6015             return p->value;
6016           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6017             p = p->left;
6018           else
6019             p = p->right;
6020         }
6021     }
6022   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6023     {
6024       if (!VEC_empty (constructor_elt, constructor_elements)
6025           && (VEC_last (constructor_elt, constructor_elements)->index
6026               == field))
6027         return VEC_last (constructor_elt, constructor_elements)->value;
6028     }
6029   return 0;
6030 }
6031
6032 /* "Output" the next constructor element.
6033    At top level, really output it to assembler code now.
6034    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6035    TYPE is the data type that the containing data type wants here.
6036    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6037    If VALUE is a string constant, STRICT_STRING is true if it is
6038    unparenthesized or we should not warn here for it being parenthesized.
6039    For other types of VALUE, STRICT_STRING is not used.
6040
6041    PENDING if non-nil means output pending elements that belong
6042    right after this element.  (PENDING is normally 1;
6043    it is 0 while outputting pending elements, to avoid recursion.)  */
6044
6045 static void
6046 output_init_element (tree value, bool strict_string, tree type, tree field,
6047                      int pending)
6048 {
6049   constructor_elt *celt;
6050
6051   if (type == error_mark_node || value == error_mark_node)
6052     {
6053       constructor_erroneous = 1;
6054       return;
6055     }
6056   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6057       && (TREE_CODE (value) == STRING_CST
6058           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6059       && !(TREE_CODE (value) == STRING_CST
6060            && TREE_CODE (type) == ARRAY_TYPE
6061            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6062       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6063                      TYPE_MAIN_VARIANT (type)))
6064     value = array_to_pointer_conversion (value);
6065
6066   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6067       && require_constant_value && !flag_isoc99 && pending)
6068     {
6069       /* As an extension, allow initializing objects with static storage
6070          duration with compound literals (which are then treated just as
6071          the brace enclosed list they contain).  */
6072       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6073       value = DECL_INITIAL (decl);
6074     }
6075
6076   if (value == error_mark_node)
6077     constructor_erroneous = 1;
6078   else if (!TREE_CONSTANT (value))
6079     constructor_constant = 0;
6080   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6081            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6082                 || TREE_CODE (constructor_type) == UNION_TYPE)
6083                && DECL_C_BIT_FIELD (field)
6084                && TREE_CODE (value) != INTEGER_CST))
6085     constructor_simple = 0;
6086
6087   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6088     {
6089       if (require_constant_value)
6090         {
6091           error_init ("initializer element is not constant");
6092           value = error_mark_node;
6093         }
6094       else if (require_constant_elements)
6095         pedwarn ("initializer element is not computable at load time");
6096     }
6097
6098   /* If this field is empty (and not at the end of structure),
6099      don't do anything other than checking the initializer.  */
6100   if (field
6101       && (TREE_TYPE (field) == error_mark_node
6102           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6103               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6104               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6105                   || TREE_CHAIN (field)))))
6106     return;
6107
6108   value = digest_init (type, value, strict_string, require_constant_value);
6109   if (value == error_mark_node)
6110     {
6111       constructor_erroneous = 1;
6112       return;
6113     }
6114
6115   /* If this element doesn't come next in sequence,
6116      put it on constructor_pending_elts.  */
6117   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6118       && (!constructor_incremental
6119           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6120     {
6121       if (constructor_incremental
6122           && tree_int_cst_lt (field, constructor_unfilled_index))
6123         set_nonincremental_init ();
6124
6125       add_pending_init (field, value);
6126       return;
6127     }
6128   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6129            && (!constructor_incremental
6130                || field != constructor_unfilled_fields))
6131     {
6132       /* We do this for records but not for unions.  In a union,
6133          no matter which field is specified, it can be initialized
6134          right away since it starts at the beginning of the union.  */
6135       if (constructor_incremental)
6136         {
6137           if (!constructor_unfilled_fields)
6138             set_nonincremental_init ();
6139           else
6140             {
6141               tree bitpos, unfillpos;
6142
6143               bitpos = bit_position (field);
6144               unfillpos = bit_position (constructor_unfilled_fields);
6145
6146               if (tree_int_cst_lt (bitpos, unfillpos))
6147                 set_nonincremental_init ();
6148             }
6149         }
6150
6151       add_pending_init (field, value);
6152       return;
6153     }
6154   else if (TREE_CODE (constructor_type) == UNION_TYPE
6155            && !VEC_empty (constructor_elt, constructor_elements))
6156     {
6157       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6158                                        constructor_elements)->value))
6159         warning_init ("initialized field with side-effects overwritten");
6160
6161       /* We can have just one union field set.  */
6162       constructor_elements = 0;
6163     }
6164
6165   /* Otherwise, output this element either to
6166      constructor_elements or to the assembler file.  */
6167
6168   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6169   celt->index = field;
6170   celt->value = value;
6171
6172   /* Advance the variable that indicates sequential elements output.  */
6173   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6174     constructor_unfilled_index
6175       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6176                     bitsize_one_node);
6177   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6178     {
6179       constructor_unfilled_fields
6180         = TREE_CHAIN (constructor_unfilled_fields);
6181
6182       /* Skip any nameless bit fields.  */
6183       while (constructor_unfilled_fields != 0
6184              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6185              && DECL_NAME (constructor_unfilled_fields) == 0)
6186         constructor_unfilled_fields =
6187           TREE_CHAIN (constructor_unfilled_fields);
6188     }
6189   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6190     constructor_unfilled_fields = 0;
6191
6192   /* Now output any pending elements which have become next.  */
6193   if (pending)
6194     output_pending_init_elements (0);
6195 }
6196
6197 /* Output any pending elements which have become next.
6198    As we output elements, constructor_unfilled_{fields,index}
6199    advances, which may cause other elements to become next;
6200    if so, they too are output.
6201
6202    If ALL is 0, we return when there are
6203    no more pending elements to output now.
6204
6205    If ALL is 1, we output space as necessary so that
6206    we can output all the pending elements.  */
6207
6208 static void
6209 output_pending_init_elements (int all)
6210 {
6211   struct init_node *elt = constructor_pending_elts;
6212   tree next;
6213
6214  retry:
6215
6216   /* Look through the whole pending tree.
6217      If we find an element that should be output now,
6218      output it.  Otherwise, set NEXT to the element
6219      that comes first among those still pending.  */
6220
6221   next = 0;
6222   while (elt)
6223     {
6224       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6225         {
6226           if (tree_int_cst_equal (elt->purpose,
6227                                   constructor_unfilled_index))
6228             output_init_element (elt->value, true,
6229                                  TREE_TYPE (constructor_type),
6230                                  constructor_unfilled_index, 0);
6231           else if (tree_int_cst_lt (constructor_unfilled_index,
6232                                     elt->purpose))
6233             {
6234               /* Advance to the next smaller node.  */
6235               if (elt->left)
6236                 elt = elt->left;
6237               else
6238                 {
6239                   /* We have reached the smallest node bigger than the
6240                      current unfilled index.  Fill the space first.  */
6241                   next = elt->purpose;
6242                   break;
6243                 }
6244             }
6245           else
6246             {
6247               /* Advance to the next bigger node.  */
6248               if (elt->right)
6249                 elt = elt->right;
6250               else
6251                 {
6252                   /* We have reached the biggest node in a subtree.  Find
6253                      the parent of it, which is the next bigger node.  */
6254                   while (elt->parent && elt->parent->right == elt)
6255                     elt = elt->parent;
6256                   elt = elt->parent;
6257                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6258                                               elt->purpose))
6259                     {
6260                       next = elt->purpose;
6261                       break;
6262                     }
6263                 }
6264             }
6265         }
6266       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6267                || TREE_CODE (constructor_type) == UNION_TYPE)
6268         {
6269           tree ctor_unfilled_bitpos, elt_bitpos;
6270
6271           /* If the current record is complete we are done.  */
6272           if (constructor_unfilled_fields == 0)
6273             break;
6274
6275           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6276           elt_bitpos = bit_position (elt->purpose);
6277           /* We can't compare fields here because there might be empty
6278              fields in between.  */
6279           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6280             {
6281               constructor_unfilled_fields = elt->purpose;
6282               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6283                                    elt->purpose, 0);
6284             }
6285           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6286             {
6287               /* Advance to the next smaller node.  */
6288               if (elt->left)
6289                 elt = elt->left;
6290               else
6291                 {
6292                   /* We have reached the smallest node bigger than the
6293                      current unfilled field.  Fill the space first.  */
6294                   next = elt->purpose;
6295                   break;
6296                 }
6297             }
6298           else
6299             {
6300               /* Advance to the next bigger node.  */
6301               if (elt->right)
6302                 elt = elt->right;
6303               else
6304                 {
6305                   /* We have reached the biggest node in a subtree.  Find
6306                      the parent of it, which is the next bigger node.  */
6307                   while (elt->parent && elt->parent->right == elt)
6308                     elt = elt->parent;
6309                   elt = elt->parent;
6310                   if (elt
6311                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6312                                            bit_position (elt->purpose))))
6313                     {
6314                       next = elt->purpose;
6315                       break;
6316                     }
6317                 }
6318             }
6319         }
6320     }
6321
6322   /* Ordinarily return, but not if we want to output all
6323      and there are elements left.  */
6324   if (!(all && next != 0))
6325     return;
6326
6327   /* If it's not incremental, just skip over the gap, so that after
6328      jumping to retry we will output the next successive element.  */
6329   if (TREE_CODE (constructor_type) == RECORD_TYPE
6330       || TREE_CODE (constructor_type) == UNION_TYPE)
6331     constructor_unfilled_fields = next;
6332   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6333     constructor_unfilled_index = next;
6334
6335   /* ELT now points to the node in the pending tree with the next
6336      initializer to output.  */
6337   goto retry;
6338 }
6339 \f
6340 /* Add one non-braced element to the current constructor level.
6341    This adjusts the current position within the constructor's type.
6342    This may also start or terminate implicit levels
6343    to handle a partly-braced initializer.
6344
6345    Once this has found the correct level for the new element,
6346    it calls output_init_element.  */
6347
6348 void
6349 process_init_element (struct c_expr value)
6350 {
6351   tree orig_value = value.value;
6352   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6353   bool strict_string = value.original_code == STRING_CST;
6354
6355   designator_depth = 0;
6356   designator_erroneous = 0;
6357
6358   /* Handle superfluous braces around string cst as in
6359      char x[] = {"foo"}; */
6360   if (string_flag
6361       && constructor_type
6362       && TREE_CODE (constructor_type) == ARRAY_TYPE
6363       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6364       && integer_zerop (constructor_unfilled_index))
6365     {
6366       if (constructor_stack->replacement_value.value)
6367         error_init ("excess elements in char array initializer");
6368       constructor_stack->replacement_value = value;
6369       return;
6370     }
6371
6372   if (constructor_stack->replacement_value.value != 0)
6373     {
6374       error_init ("excess elements in struct initializer");
6375       return;
6376     }
6377
6378   /* Ignore elements of a brace group if it is entirely superfluous
6379      and has already been diagnosed.  */
6380   if (constructor_type == 0)
6381     return;
6382
6383   /* If we've exhausted any levels that didn't have braces,
6384      pop them now.  */
6385   while (constructor_stack->implicit)
6386     {
6387       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6388            || TREE_CODE (constructor_type) == UNION_TYPE)
6389           && constructor_fields == 0)
6390         process_init_element (pop_init_level (1));
6391       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6392                && (constructor_max_index == 0
6393                    || tree_int_cst_lt (constructor_max_index,
6394                                        constructor_index)))
6395         process_init_element (pop_init_level (1));
6396       else
6397         break;
6398     }
6399
6400   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6401   if (constructor_range_stack)
6402     {
6403       /* If value is a compound literal and we'll be just using its
6404          content, don't put it into a SAVE_EXPR.  */
6405       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6406           || !require_constant_value
6407           || flag_isoc99)
6408         value.value = save_expr (value.value);
6409     }
6410
6411   while (1)
6412     {
6413       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6414         {
6415           tree fieldtype;
6416           enum tree_code fieldcode;
6417
6418           if (constructor_fields == 0)
6419             {
6420               pedwarn_init ("excess elements in struct initializer");
6421               break;
6422             }
6423
6424           fieldtype = TREE_TYPE (constructor_fields);
6425           if (fieldtype != error_mark_node)
6426             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6427           fieldcode = TREE_CODE (fieldtype);
6428
6429           /* Error for non-static initialization of a flexible array member.  */
6430           if (fieldcode == ARRAY_TYPE
6431               && !require_constant_value
6432               && TYPE_SIZE (fieldtype) == NULL_TREE
6433               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6434             {
6435               error_init ("non-static initialization of a flexible array member");
6436               break;
6437             }
6438
6439           /* Accept a string constant to initialize a subarray.  */
6440           if (value.value != 0
6441               && fieldcode == ARRAY_TYPE
6442               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6443               && string_flag)
6444             value.value = orig_value;
6445           /* Otherwise, if we have come to a subaggregate,
6446              and we don't have an element of its type, push into it.  */
6447           else if (value.value != 0
6448                    && value.value != error_mark_node
6449                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6450                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6451                        || fieldcode == UNION_TYPE))
6452             {
6453               push_init_level (1);
6454               continue;
6455             }
6456
6457           if (value.value)
6458             {
6459               push_member_name (constructor_fields);
6460               output_init_element (value.value, strict_string,
6461                                    fieldtype, constructor_fields, 1);
6462               RESTORE_SPELLING_DEPTH (constructor_depth);
6463             }
6464           else
6465             /* Do the bookkeeping for an element that was
6466                directly output as a constructor.  */
6467             {
6468               /* For a record, keep track of end position of last field.  */
6469               if (DECL_SIZE (constructor_fields))
6470                 constructor_bit_index
6471                   = size_binop (PLUS_EXPR,
6472                                 bit_position (constructor_fields),
6473                                 DECL_SIZE (constructor_fields));
6474
6475               /* If the current field was the first one not yet written out,
6476                  it isn't now, so update.  */
6477               if (constructor_unfilled_fields == constructor_fields)
6478                 {
6479                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6480                   /* Skip any nameless bit fields.  */
6481                   while (constructor_unfilled_fields != 0
6482                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6483                          && DECL_NAME (constructor_unfilled_fields) == 0)
6484                     constructor_unfilled_fields =
6485                       TREE_CHAIN (constructor_unfilled_fields);
6486                 }
6487             }
6488
6489           constructor_fields = TREE_CHAIN (constructor_fields);
6490           /* Skip any nameless bit fields at the beginning.  */
6491           while (constructor_fields != 0
6492                  && DECL_C_BIT_FIELD (constructor_fields)
6493                  && DECL_NAME (constructor_fields) == 0)
6494             constructor_fields = TREE_CHAIN (constructor_fields);
6495         }
6496       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6497         {
6498           tree fieldtype;
6499           enum tree_code fieldcode;
6500
6501           if (constructor_fields == 0)
6502             {
6503               pedwarn_init ("excess elements in union initializer");
6504               break;
6505             }
6506
6507           fieldtype = TREE_TYPE (constructor_fields);
6508           if (fieldtype != error_mark_node)
6509             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6510           fieldcode = TREE_CODE (fieldtype);
6511
6512           /* Warn that traditional C rejects initialization of unions.
6513              We skip the warning if the value is zero.  This is done
6514              under the assumption that the zero initializer in user
6515              code appears conditioned on e.g. __STDC__ to avoid
6516              "missing initializer" warnings and relies on default
6517              initialization to zero in the traditional C case.
6518              We also skip the warning if the initializer is designated,
6519              again on the assumption that this must be conditional on
6520              __STDC__ anyway (and we've already complained about the
6521              member-designator already).  */
6522           if (!in_system_header && !constructor_designated
6523               && !(value.value && (integer_zerop (value.value)
6524                                    || real_zerop (value.value))))
6525             warning (OPT_Wtraditional, "traditional C rejects initialization "
6526                      "of unions");
6527
6528           /* Accept a string constant to initialize a subarray.  */
6529           if (value.value != 0
6530               && fieldcode == ARRAY_TYPE
6531               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6532               && string_flag)
6533             value.value = orig_value;
6534           /* Otherwise, if we have come to a subaggregate,
6535              and we don't have an element of its type, push into it.  */
6536           else if (value.value != 0
6537                    && value.value != error_mark_node
6538                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6539                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6540                        || fieldcode == UNION_TYPE))
6541             {
6542               push_init_level (1);
6543               continue;
6544             }
6545
6546           if (value.value)
6547             {
6548               push_member_name (constructor_fields);
6549               output_init_element (value.value, strict_string,
6550                                    fieldtype, constructor_fields, 1);
6551               RESTORE_SPELLING_DEPTH (constructor_depth);
6552             }
6553           else
6554             /* Do the bookkeeping for an element that was
6555                directly output as a constructor.  */
6556             {
6557               constructor_bit_index = DECL_SIZE (constructor_fields);
6558               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6559             }
6560
6561           constructor_fields = 0;
6562         }
6563       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6564         {
6565           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6566           enum tree_code eltcode = TREE_CODE (elttype);
6567
6568           /* Accept a string constant to initialize a subarray.  */
6569           if (value.value != 0
6570               && eltcode == ARRAY_TYPE
6571               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6572               && string_flag)
6573             value.value = orig_value;
6574           /* Otherwise, if we have come to a subaggregate,
6575              and we don't have an element of its type, push into it.  */
6576           else if (value.value != 0
6577                    && value.value != error_mark_node
6578                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6579                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6580                        || eltcode == UNION_TYPE))
6581             {
6582               push_init_level (1);
6583               continue;
6584             }
6585
6586           if (constructor_max_index != 0
6587               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6588                   || integer_all_onesp (constructor_max_index)))
6589             {
6590               pedwarn_init ("excess elements in array initializer");
6591               break;
6592             }
6593
6594           /* Now output the actual element.  */
6595           if (value.value)
6596             {
6597               push_array_bounds (tree_low_cst (constructor_index, 0));
6598               output_init_element (value.value, strict_string,
6599                                    elttype, constructor_index, 1);
6600               RESTORE_SPELLING_DEPTH (constructor_depth);
6601             }
6602
6603           constructor_index
6604             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6605
6606           if (!value.value)
6607             /* If we are doing the bookkeeping for an element that was
6608                directly output as a constructor, we must update
6609                constructor_unfilled_index.  */
6610             constructor_unfilled_index = constructor_index;
6611         }
6612       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6613         {
6614           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6615
6616          /* Do a basic check of initializer size.  Note that vectors
6617             always have a fixed size derived from their type.  */
6618           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6619             {
6620               pedwarn_init ("excess elements in vector initializer");
6621               break;
6622             }
6623
6624           /* Now output the actual element.  */
6625           if (value.value)
6626             output_init_element (value.value, strict_string,
6627                                  elttype, constructor_index, 1);
6628
6629           constructor_index
6630             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6631
6632           if (!value.value)
6633             /* If we are doing the bookkeeping for an element that was
6634                directly output as a constructor, we must update
6635                constructor_unfilled_index.  */
6636             constructor_unfilled_index = constructor_index;
6637         }
6638
6639       /* Handle the sole element allowed in a braced initializer
6640          for a scalar variable.  */
6641       else if (constructor_type != error_mark_node
6642                && constructor_fields == 0)
6643         {
6644           pedwarn_init ("excess elements in scalar initializer");
6645           break;
6646         }
6647       else
6648         {
6649           if (value.value)
6650             output_init_element (value.value, strict_string,
6651                                  constructor_type, NULL_TREE, 1);
6652           constructor_fields = 0;
6653         }
6654
6655       /* Handle range initializers either at this level or anywhere higher
6656          in the designator stack.  */
6657       if (constructor_range_stack)
6658         {
6659           struct constructor_range_stack *p, *range_stack;
6660           int finish = 0;
6661
6662           range_stack = constructor_range_stack;
6663           constructor_range_stack = 0;
6664           while (constructor_stack != range_stack->stack)
6665             {
6666               gcc_assert (constructor_stack->implicit);
6667               process_init_element (pop_init_level (1));
6668             }
6669           for (p = range_stack;
6670                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6671                p = p->prev)
6672             {
6673               gcc_assert (constructor_stack->implicit);
6674               process_init_element (pop_init_level (1));
6675             }
6676
6677           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6678           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6679             finish = 1;
6680
6681           while (1)
6682             {
6683               constructor_index = p->index;
6684               constructor_fields = p->fields;
6685               if (finish && p->range_end && p->index == p->range_start)
6686                 {
6687                   finish = 0;
6688                   p->prev = 0;
6689                 }
6690               p = p->next;
6691               if (!p)
6692                 break;
6693               push_init_level (2);
6694               p->stack = constructor_stack;
6695               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6696                 p->index = p->range_start;
6697             }
6698
6699           if (!finish)
6700             constructor_range_stack = range_stack;
6701           continue;
6702         }
6703
6704       break;
6705     }
6706
6707   constructor_range_stack = 0;
6708 }
6709 \f
6710 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6711    (guaranteed to be 'volatile' or null) and ARGS (represented using
6712    an ASM_EXPR node).  */
6713 tree
6714 build_asm_stmt (tree cv_qualifier, tree args)
6715 {
6716   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6717     ASM_VOLATILE_P (args) = 1;
6718   return add_stmt (args);
6719 }
6720
6721 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6722    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6723    SIMPLE indicates whether there was anything at all after the
6724    string in the asm expression -- asm("blah") and asm("blah" : )
6725    are subtly different.  We use a ASM_EXPR node to represent this.  */
6726 tree
6727 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6728                 bool simple)
6729 {
6730   tree tail;
6731   tree args;
6732   int i;
6733   const char *constraint;
6734   const char **oconstraints;
6735   bool allows_mem, allows_reg, is_inout;
6736   int ninputs, noutputs;
6737
6738   ninputs = list_length (inputs);
6739   noutputs = list_length (outputs);
6740   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6741
6742   string = resolve_asm_operand_names (string, outputs, inputs);
6743
6744   /* Remove output conversions that change the type but not the mode.  */
6745   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6746     {
6747       tree output = TREE_VALUE (tail);
6748
6749       /* ??? Really, this should not be here.  Users should be using a
6750          proper lvalue, dammit.  But there's a long history of using casts
6751          in the output operands.  In cases like longlong.h, this becomes a
6752          primitive form of typechecking -- if the cast can be removed, then
6753          the output operand had a type of the proper width; otherwise we'll
6754          get an error.  Gross, but ...  */
6755       STRIP_NOPS (output);
6756
6757       if (!lvalue_or_else (output, lv_asm))
6758         output = error_mark_node;
6759
6760       if (output != error_mark_node
6761           && (TREE_READONLY (output)
6762               || TYPE_READONLY (TREE_TYPE (output))
6763               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6764                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6765                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6766         readonly_error (output, lv_asm);
6767
6768       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6769       oconstraints[i] = constraint;
6770
6771       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6772                                    &allows_mem, &allows_reg, &is_inout))
6773         {
6774           /* If the operand is going to end up in memory,
6775              mark it addressable.  */
6776           if (!allows_reg && !c_mark_addressable (output))
6777             output = error_mark_node;
6778         }
6779       else
6780         output = error_mark_node;
6781
6782       TREE_VALUE (tail) = output;
6783     }
6784
6785   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6786     {
6787       tree input;
6788
6789       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6790       input = TREE_VALUE (tail);
6791
6792       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6793                                   oconstraints, &allows_mem, &allows_reg))
6794         {
6795           /* If the operand is going to end up in memory,
6796              mark it addressable.  */
6797           if (!allows_reg && allows_mem)
6798             {
6799               /* Strip the nops as we allow this case.  FIXME, this really
6800                  should be rejected or made deprecated.  */
6801               STRIP_NOPS (input);
6802               if (!c_mark_addressable (input))
6803                 input = error_mark_node;
6804           }
6805         }
6806       else
6807         input = error_mark_node;
6808
6809       TREE_VALUE (tail) = input;
6810     }
6811
6812   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6813
6814   /* asm statements without outputs, including simple ones, are treated
6815      as volatile.  */
6816   ASM_INPUT_P (args) = simple;
6817   ASM_VOLATILE_P (args) = (noutputs == 0);
6818
6819   return args;
6820 }
6821 \f
6822 /* Generate a goto statement to LABEL.  */
6823
6824 tree
6825 c_finish_goto_label (tree label)
6826 {
6827   tree decl = lookup_label (label);
6828   if (!decl)
6829     return NULL_TREE;
6830
6831   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6832     {
6833       error ("jump into statement expression");
6834       return NULL_TREE;
6835     }
6836
6837   if (C_DECL_UNJUMPABLE_VM (decl))
6838     {
6839       error ("jump into scope of identifier with variably modified type");
6840       return NULL_TREE;
6841     }
6842
6843   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6844     {
6845       /* No jump from outside this statement expression context, so
6846          record that there is a jump from within this context.  */
6847       struct c_label_list *nlist;
6848       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6849       nlist->next = label_context_stack_se->labels_used;
6850       nlist->label = decl;
6851       label_context_stack_se->labels_used = nlist;
6852     }
6853
6854   if (!C_DECL_UNDEFINABLE_VM (decl))
6855     {
6856       /* No jump from outside this context context of identifiers with
6857          variably modified type, so record that there is a jump from
6858          within this context.  */
6859       struct c_label_list *nlist;
6860       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6861       nlist->next = label_context_stack_vm->labels_used;
6862       nlist->label = decl;
6863       label_context_stack_vm->labels_used = nlist;
6864     }
6865
6866   TREE_USED (decl) = 1;
6867   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6868 }
6869
6870 /* Generate a computed goto statement to EXPR.  */
6871
6872 tree
6873 c_finish_goto_ptr (tree expr)
6874 {
6875   if (pedantic)
6876     pedwarn ("ISO C forbids %<goto *expr;%>");
6877   expr = convert (ptr_type_node, expr);
6878   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6879 }
6880
6881 /* Generate a C `return' statement.  RETVAL is the expression for what
6882    to return, or a null pointer for `return;' with no value.  */
6883
6884 tree
6885 c_finish_return (tree retval)
6886 {
6887   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6888   bool no_warning = false;
6889
6890   if (TREE_THIS_VOLATILE (current_function_decl))
6891     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6892
6893   if (!retval)
6894     {
6895       current_function_returns_null = 1;
6896       if ((warn_return_type || flag_isoc99)
6897           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6898         {
6899           pedwarn_c99 ("%<return%> with no value, in "
6900                        "function returning non-void");
6901           no_warning = true;
6902         }
6903     }
6904   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6905     {
6906       current_function_returns_null = 1;
6907       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6908         pedwarn ("%<return%> with a value, in function returning void");
6909     }
6910   else
6911     {
6912       tree t = convert_for_assignment (valtype, retval, ic_return,
6913                                        NULL_TREE, NULL_TREE, 0);
6914       tree res = DECL_RESULT (current_function_decl);
6915       tree inner;
6916
6917       current_function_returns_value = 1;
6918       if (t == error_mark_node)
6919         return NULL_TREE;
6920
6921       inner = t = convert (TREE_TYPE (res), t);
6922
6923       /* Strip any conversions, additions, and subtractions, and see if
6924          we are returning the address of a local variable.  Warn if so.  */
6925       while (1)
6926         {
6927           switch (TREE_CODE (inner))
6928             {
6929             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6930             case PLUS_EXPR:
6931               inner = TREE_OPERAND (inner, 0);
6932               continue;
6933
6934             case MINUS_EXPR:
6935               /* If the second operand of the MINUS_EXPR has a pointer
6936                  type (or is converted from it), this may be valid, so
6937                  don't give a warning.  */
6938               {
6939                 tree op1 = TREE_OPERAND (inner, 1);
6940
6941                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6942                        && (TREE_CODE (op1) == NOP_EXPR
6943                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6944                            || TREE_CODE (op1) == CONVERT_EXPR))
6945                   op1 = TREE_OPERAND (op1, 0);
6946
6947                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6948                   break;
6949
6950                 inner = TREE_OPERAND (inner, 0);
6951                 continue;
6952               }
6953
6954             case ADDR_EXPR:
6955               inner = TREE_OPERAND (inner, 0);
6956
6957               while (REFERENCE_CLASS_P (inner)
6958                      && TREE_CODE (inner) != INDIRECT_REF)
6959                 inner = TREE_OPERAND (inner, 0);
6960
6961               if (DECL_P (inner)
6962                   && !DECL_EXTERNAL (inner)
6963                   && !TREE_STATIC (inner)
6964                   && DECL_CONTEXT (inner) == current_function_decl)
6965                 warning (0, "function returns address of local variable");
6966               break;
6967
6968             default:
6969               break;
6970             }
6971
6972           break;
6973         }
6974
6975       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6976     }
6977
6978   ret_stmt = build_stmt (RETURN_EXPR, retval);
6979   TREE_NO_WARNING (ret_stmt) |= no_warning;
6980   return add_stmt (ret_stmt);
6981 }
6982 \f
6983 struct c_switch {
6984   /* The SWITCH_EXPR being built.  */
6985   tree switch_expr;
6986
6987   /* The original type of the testing expression, i.e. before the
6988      default conversion is applied.  */
6989   tree orig_type;
6990
6991   /* A splay-tree mapping the low element of a case range to the high
6992      element, or NULL_TREE if there is no high element.  Used to
6993      determine whether or not a new case label duplicates an old case
6994      label.  We need a tree, rather than simply a hash table, because
6995      of the GNU case range extension.  */
6996   splay_tree cases;
6997
6998   /* Number of nested statement expressions within this switch
6999      statement; if nonzero, case and default labels may not
7000      appear.  */
7001   unsigned int blocked_stmt_expr;
7002
7003   /* Scope of outermost declarations of identifiers with variably
7004      modified type within this switch statement; if nonzero, case and
7005      default labels may not appear.  */
7006   unsigned int blocked_vm;
7007
7008   /* The next node on the stack.  */
7009   struct c_switch *next;
7010 };
7011
7012 /* A stack of the currently active switch statements.  The innermost
7013    switch statement is on the top of the stack.  There is no need to
7014    mark the stack for garbage collection because it is only active
7015    during the processing of the body of a function, and we never
7016    collect at that point.  */
7017
7018 struct c_switch *c_switch_stack;
7019
7020 /* Start a C switch statement, testing expression EXP.  Return the new
7021    SWITCH_EXPR.  */
7022
7023 tree
7024 c_start_case (tree exp)
7025 {
7026   enum tree_code code;
7027   tree type, orig_type = error_mark_node;
7028   struct c_switch *cs;
7029
7030   if (exp != error_mark_node)
7031     {
7032       code = TREE_CODE (TREE_TYPE (exp));
7033       orig_type = TREE_TYPE (exp);
7034
7035       if (!INTEGRAL_TYPE_P (orig_type)
7036           && code != ERROR_MARK)
7037         {
7038           error ("switch quantity not an integer");
7039           exp = integer_zero_node;
7040           orig_type = error_mark_node;
7041         }
7042       else
7043         {
7044           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
7045
7046           if (!in_system_header
7047               && (type == long_integer_type_node
7048                   || type == long_unsigned_type_node))
7049             warning (OPT_Wtraditional, "%<long%> switch expression not "
7050                      "converted to %<int%> in ISO C");
7051
7052           exp = default_conversion (exp);
7053           type = TREE_TYPE (exp);
7054         }
7055     }
7056
7057   /* Add this new SWITCH_EXPR to the stack.  */
7058   cs = XNEW (struct c_switch);
7059   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7060   cs->orig_type = orig_type;
7061   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7062   cs->blocked_stmt_expr = 0;
7063   cs->blocked_vm = 0;
7064   cs->next = c_switch_stack;
7065   c_switch_stack = cs;
7066
7067   return add_stmt (cs->switch_expr);
7068 }
7069
7070 /* Process a case label.  */
7071
7072 tree
7073 do_case (tree low_value, tree high_value)
7074 {
7075   tree label = NULL_TREE;
7076
7077   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7078       && !c_switch_stack->blocked_vm)
7079     {
7080       label = c_add_case_label (c_switch_stack->cases,
7081                                 SWITCH_COND (c_switch_stack->switch_expr),
7082                                 c_switch_stack->orig_type,
7083                                 low_value, high_value);
7084       if (label == error_mark_node)
7085         label = NULL_TREE;
7086     }
7087   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7088     {
7089       if (low_value)
7090         error ("case label in statement expression not containing "
7091                "enclosing switch statement");
7092       else
7093         error ("%<default%> label in statement expression not containing "
7094                "enclosing switch statement");
7095     }
7096   else if (c_switch_stack && c_switch_stack->blocked_vm)
7097     {
7098       if (low_value)
7099         error ("case label in scope of identifier with variably modified "
7100                "type not containing enclosing switch statement");
7101       else
7102         error ("%<default%> label in scope of identifier with variably "
7103                "modified type not containing enclosing switch statement");
7104     }
7105   else if (low_value)
7106     error ("case label not within a switch statement");
7107   else
7108     error ("%<default%> label not within a switch statement");
7109
7110   return label;
7111 }
7112
7113 /* Finish the switch statement.  */
7114
7115 void
7116 c_finish_case (tree body)
7117 {
7118   struct c_switch *cs = c_switch_stack;
7119   location_t switch_location;
7120
7121   SWITCH_BODY (cs->switch_expr) = body;
7122
7123   /* We must not be within a statement expression nested in the switch
7124      at this point; we might, however, be within the scope of an
7125      identifier with variably modified type nested in the switch.  */
7126   gcc_assert (!cs->blocked_stmt_expr);
7127
7128   /* Emit warnings as needed.  */
7129   if (EXPR_HAS_LOCATION (cs->switch_expr))
7130     switch_location = EXPR_LOCATION (cs->switch_expr);
7131   else
7132     switch_location = input_location;
7133   c_do_switch_warnings (cs->cases, switch_location,
7134                         TREE_TYPE (cs->switch_expr),
7135                         SWITCH_COND (cs->switch_expr));
7136
7137   /* Pop the stack.  */
7138   c_switch_stack = cs->next;
7139   splay_tree_delete (cs->cases);
7140   XDELETE (cs);
7141 }
7142 \f
7143 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7144    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7145    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7146    statement, and was not surrounded with parenthesis.  */
7147
7148 void
7149 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7150                   tree else_block, bool nested_if)
7151 {
7152   tree stmt;
7153
7154   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7155   if (warn_parentheses && nested_if && else_block == NULL)
7156     {
7157       tree inner_if = then_block;
7158
7159       /* We know from the grammar productions that there is an IF nested
7160          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7161          it might not be exactly THEN_BLOCK, but should be the last
7162          non-container statement within.  */
7163       while (1)
7164         switch (TREE_CODE (inner_if))
7165           {
7166           case COND_EXPR:
7167             goto found;
7168           case BIND_EXPR:
7169             inner_if = BIND_EXPR_BODY (inner_if);
7170             break;
7171           case STATEMENT_LIST:
7172             inner_if = expr_last (then_block);
7173             break;
7174           case TRY_FINALLY_EXPR:
7175           case TRY_CATCH_EXPR:
7176             inner_if = TREE_OPERAND (inner_if, 0);
7177             break;
7178           default:
7179             gcc_unreachable ();
7180           }
7181     found:
7182
7183       if (COND_EXPR_ELSE (inner_if))
7184          warning (OPT_Wparentheses,
7185                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7186                   &if_locus);
7187     }
7188
7189   empty_body_warning (then_block, else_block);
7190
7191   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7192   SET_EXPR_LOCATION (stmt, if_locus);
7193   add_stmt (stmt);
7194 }
7195
7196 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7197    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7198    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7199    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7200    the continue label.  Everything is allowed to be NULL.  */
7201
7202 void
7203 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7204                tree blab, tree clab, bool cond_is_first)
7205 {
7206   tree entry = NULL, exit = NULL, t;
7207
7208   /* If the condition is zero don't generate a loop construct.  */
7209   if (cond && integer_zerop (cond))
7210     {
7211       if (cond_is_first)
7212         {
7213           t = build_and_jump (&blab);
7214           SET_EXPR_LOCATION (t, start_locus);
7215           add_stmt (t);
7216         }
7217     }
7218   else
7219     {
7220       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7221
7222       /* If we have an exit condition, then we build an IF with gotos either
7223          out of the loop, or to the top of it.  If there's no exit condition,
7224          then we just build a jump back to the top.  */
7225       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7226
7227       if (cond && !integer_nonzerop (cond))
7228         {
7229           /* Canonicalize the loop condition to the end.  This means
7230              generating a branch to the loop condition.  Reuse the
7231              continue label, if possible.  */
7232           if (cond_is_first)
7233             {
7234               if (incr || !clab)
7235                 {
7236                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7237                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7238                 }
7239               else
7240                 t = build1 (GOTO_EXPR, void_type_node, clab);
7241               SET_EXPR_LOCATION (t, start_locus);
7242               add_stmt (t);
7243             }
7244
7245           t = build_and_jump (&blab);
7246           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7247           if (cond_is_first)
7248             SET_EXPR_LOCATION (exit, start_locus);
7249           else
7250             SET_EXPR_LOCATION (exit, input_location);
7251         }
7252
7253       add_stmt (top);
7254     }
7255
7256   if (body)
7257     add_stmt (body);
7258   if (clab)
7259     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7260   if (incr)
7261     add_stmt (incr);
7262   if (entry)
7263     add_stmt (entry);
7264   if (exit)
7265     add_stmt (exit);
7266   if (blab)
7267     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7268 }
7269
7270 tree
7271 c_finish_bc_stmt (tree *label_p, bool is_break)
7272 {
7273   bool skip;
7274   tree label = *label_p;
7275
7276   /* In switch statements break is sometimes stylistically used after
7277      a return statement.  This can lead to spurious warnings about
7278      control reaching the end of a non-void function when it is
7279      inlined.  Note that we are calling block_may_fallthru with
7280      language specific tree nodes; this works because
7281      block_may_fallthru returns true when given something it does not
7282      understand.  */
7283   skip = !block_may_fallthru (cur_stmt_list);
7284
7285   if (!label)
7286     {
7287       if (!skip)
7288         *label_p = label = create_artificial_label ();
7289     }
7290   else if (TREE_CODE (label) == LABEL_DECL)
7291     ;
7292   else switch (TREE_INT_CST_LOW (label))
7293     {
7294     case 0:
7295       if (is_break)
7296         error ("break statement not within loop or switch");
7297       else
7298         error ("continue statement not within a loop");
7299       return NULL_TREE;
7300
7301     case 1:
7302       gcc_assert (is_break);
7303       error ("break statement used with OpenMP for loop");
7304       return NULL_TREE;
7305
7306     default:
7307       gcc_unreachable ();
7308     }
7309
7310   if (skip)
7311     return NULL_TREE;
7312
7313   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7314 }
7315
7316 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7317
7318 static void
7319 emit_side_effect_warnings (tree expr)
7320 {
7321   if (expr == error_mark_node)
7322     ;
7323   else if (!TREE_SIDE_EFFECTS (expr))
7324     {
7325       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7326         warning (0, "%Hstatement with no effect",
7327                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7328     }
7329   else if (warn_unused_value)
7330     warn_if_unused_value (expr, input_location);
7331 }
7332
7333 /* Process an expression as if it were a complete statement.  Emit
7334    diagnostics, but do not call ADD_STMT.  */
7335
7336 tree
7337 c_process_expr_stmt (tree expr)
7338 {
7339   if (!expr)
7340     return NULL_TREE;
7341
7342   if (warn_sequence_point)
7343     verify_sequence_points (expr);
7344
7345   if (TREE_TYPE (expr) != error_mark_node
7346       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7347       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7348     error ("expression statement has incomplete type");
7349
7350   /* If we're not processing a statement expression, warn about unused values.
7351      Warnings for statement expressions will be emitted later, once we figure
7352      out which is the result.  */
7353   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7354       && (extra_warnings || warn_unused_value))
7355     emit_side_effect_warnings (expr);
7356
7357   /* If the expression is not of a type to which we cannot assign a line
7358      number, wrap the thing in a no-op NOP_EXPR.  */
7359   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7360     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7361
7362   if (EXPR_P (expr))
7363     SET_EXPR_LOCATION (expr, input_location);
7364
7365   return expr;
7366 }
7367
7368 /* Emit an expression as a statement.  */
7369
7370 tree
7371 c_finish_expr_stmt (tree expr)
7372 {
7373   if (expr)
7374     return add_stmt (c_process_expr_stmt (expr));
7375   else
7376     return NULL;
7377 }
7378
7379 /* Do the opposite and emit a statement as an expression.  To begin,
7380    create a new binding level and return it.  */
7381
7382 tree
7383 c_begin_stmt_expr (void)
7384 {
7385   tree ret;
7386   struct c_label_context_se *nstack;
7387   struct c_label_list *glist;
7388
7389   /* We must force a BLOCK for this level so that, if it is not expanded
7390      later, there is a way to turn off the entire subtree of blocks that
7391      are contained in it.  */
7392   keep_next_level ();
7393   ret = c_begin_compound_stmt (true);
7394   if (c_switch_stack)
7395     {
7396       c_switch_stack->blocked_stmt_expr++;
7397       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7398     }
7399   for (glist = label_context_stack_se->labels_used;
7400        glist != NULL;
7401        glist = glist->next)
7402     {
7403       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7404     }
7405   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7406   nstack->labels_def = NULL;
7407   nstack->labels_used = NULL;
7408   nstack->next = label_context_stack_se;
7409   label_context_stack_se = nstack;
7410
7411   /* Mark the current statement list as belonging to a statement list.  */
7412   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7413
7414   return ret;
7415 }
7416
7417 tree
7418 c_finish_stmt_expr (tree body)
7419 {
7420   tree last, type, tmp, val;
7421   tree *last_p;
7422   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7423
7424   body = c_end_compound_stmt (body, true);
7425   if (c_switch_stack)
7426     {
7427       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7428       c_switch_stack->blocked_stmt_expr--;
7429     }
7430   /* It is no longer possible to jump to labels defined within this
7431      statement expression.  */
7432   for (dlist = label_context_stack_se->labels_def;
7433        dlist != NULL;
7434        dlist = dlist->next)
7435     {
7436       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7437     }
7438   /* It is again possible to define labels with a goto just outside
7439      this statement expression.  */
7440   for (glist = label_context_stack_se->next->labels_used;
7441        glist != NULL;
7442        glist = glist->next)
7443     {
7444       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7445       glist_prev = glist;
7446     }
7447   if (glist_prev != NULL)
7448     glist_prev->next = label_context_stack_se->labels_used;
7449   else
7450     label_context_stack_se->next->labels_used
7451       = label_context_stack_se->labels_used;
7452   label_context_stack_se = label_context_stack_se->next;
7453
7454   /* Locate the last statement in BODY.  See c_end_compound_stmt
7455      about always returning a BIND_EXPR.  */
7456   last_p = &BIND_EXPR_BODY (body);
7457   last = BIND_EXPR_BODY (body);
7458
7459  continue_searching:
7460   if (TREE_CODE (last) == STATEMENT_LIST)
7461     {
7462       tree_stmt_iterator i;
7463
7464       /* This can happen with degenerate cases like ({ }).  No value.  */
7465       if (!TREE_SIDE_EFFECTS (last))
7466         return body;
7467
7468       /* If we're supposed to generate side effects warnings, process
7469          all of the statements except the last.  */
7470       if (extra_warnings || warn_unused_value)
7471         {
7472           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7473             emit_side_effect_warnings (tsi_stmt (i));
7474         }
7475       else
7476         i = tsi_last (last);
7477       last_p = tsi_stmt_ptr (i);
7478       last = *last_p;
7479     }
7480
7481   /* If the end of the list is exception related, then the list was split
7482      by a call to push_cleanup.  Continue searching.  */
7483   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7484       || TREE_CODE (last) == TRY_CATCH_EXPR)
7485     {
7486       last_p = &TREE_OPERAND (last, 0);
7487       last = *last_p;
7488       goto continue_searching;
7489     }
7490
7491   /* In the case that the BIND_EXPR is not necessary, return the
7492      expression out from inside it.  */
7493   if (last == error_mark_node
7494       || (last == BIND_EXPR_BODY (body)
7495           && BIND_EXPR_VARS (body) == NULL))
7496     {
7497       /* Do not warn if the return value of a statement expression is
7498          unused.  */
7499       if (EXPR_P (last))
7500         TREE_NO_WARNING (last) = 1;
7501       return last;
7502     }
7503
7504   /* Extract the type of said expression.  */
7505   type = TREE_TYPE (last);
7506
7507   /* If we're not returning a value at all, then the BIND_EXPR that
7508      we already have is a fine expression to return.  */
7509   if (!type || VOID_TYPE_P (type))
7510     return body;
7511
7512   /* Now that we've located the expression containing the value, it seems
7513      silly to make voidify_wrapper_expr repeat the process.  Create a
7514      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7515   tmp = create_tmp_var_raw (type, NULL);
7516
7517   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7518      tree_expr_nonnegative_p giving up immediately.  */
7519   val = last;
7520   if (TREE_CODE (val) == NOP_EXPR
7521       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7522     val = TREE_OPERAND (val, 0);
7523
7524   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7525   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7526
7527   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7528 }
7529
7530 /* Begin the scope of an identifier of variably modified type, scope
7531    number SCOPE.  Jumping from outside this scope to inside it is not
7532    permitted.  */
7533
7534 void
7535 c_begin_vm_scope (unsigned int scope)
7536 {
7537   struct c_label_context_vm *nstack;
7538   struct c_label_list *glist;
7539
7540   gcc_assert (scope > 0);
7541   if (c_switch_stack && !c_switch_stack->blocked_vm)
7542     c_switch_stack->blocked_vm = scope;
7543   for (glist = label_context_stack_vm->labels_used;
7544        glist != NULL;
7545        glist = glist->next)
7546     {
7547       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7548     }
7549   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7550   nstack->labels_def = NULL;
7551   nstack->labels_used = NULL;
7552   nstack->scope = scope;
7553   nstack->next = label_context_stack_vm;
7554   label_context_stack_vm = nstack;
7555 }
7556
7557 /* End a scope which may contain identifiers of variably modified
7558    type, scope number SCOPE.  */
7559
7560 void
7561 c_end_vm_scope (unsigned int scope)
7562 {
7563   if (label_context_stack_vm == NULL)
7564     return;
7565   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7566     c_switch_stack->blocked_vm = 0;
7567   /* We may have a number of nested scopes of identifiers with
7568      variably modified type, all at this depth.  Pop each in turn.  */
7569   while (label_context_stack_vm->scope == scope)
7570     {
7571       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7572
7573       /* It is no longer possible to jump to labels defined within this
7574          scope.  */
7575       for (dlist = label_context_stack_vm->labels_def;
7576            dlist != NULL;
7577            dlist = dlist->next)
7578         {
7579           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7580         }
7581       /* It is again possible to define labels with a goto just outside
7582          this scope.  */
7583       for (glist = label_context_stack_vm->next->labels_used;
7584            glist != NULL;
7585            glist = glist->next)
7586         {
7587           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7588           glist_prev = glist;
7589         }
7590       if (glist_prev != NULL)
7591         glist_prev->next = label_context_stack_vm->labels_used;
7592       else
7593         label_context_stack_vm->next->labels_used
7594           = label_context_stack_vm->labels_used;
7595       label_context_stack_vm = label_context_stack_vm->next;
7596     }
7597 }
7598 \f
7599 /* Begin and end compound statements.  This is as simple as pushing
7600    and popping new statement lists from the tree.  */
7601
7602 tree
7603 c_begin_compound_stmt (bool do_scope)
7604 {
7605   tree stmt = push_stmt_list ();
7606   if (do_scope)
7607     push_scope ();
7608   return stmt;
7609 }
7610
7611 tree
7612 c_end_compound_stmt (tree stmt, bool do_scope)
7613 {
7614   tree block = NULL;
7615
7616   if (do_scope)
7617     {
7618       if (c_dialect_objc ())
7619         objc_clear_super_receiver ();
7620       block = pop_scope ();
7621     }
7622
7623   stmt = pop_stmt_list (stmt);
7624   stmt = c_build_bind_expr (block, stmt);
7625
7626   /* If this compound statement is nested immediately inside a statement
7627      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7628      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7629      STATEMENT_LISTs merge, and thus we can lose track of what statement
7630      was really last.  */
7631   if (cur_stmt_list
7632       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7633       && TREE_CODE (stmt) != BIND_EXPR)
7634     {
7635       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7636       TREE_SIDE_EFFECTS (stmt) = 1;
7637     }
7638
7639   return stmt;
7640 }
7641
7642 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7643    when the current scope is exited.  EH_ONLY is true when this is not
7644    meant to apply to normal control flow transfer.  */
7645
7646 void
7647 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7648 {
7649   enum tree_code code;
7650   tree stmt, list;
7651   bool stmt_expr;
7652
7653   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7654   stmt = build_stmt (code, NULL, cleanup);
7655   add_stmt (stmt);
7656   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7657   list = push_stmt_list ();
7658   TREE_OPERAND (stmt, 0) = list;
7659   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7660 }
7661 \f
7662 /* Build a binary-operation expression without default conversions.
7663    CODE is the kind of expression to build.
7664    This function differs from `build' in several ways:
7665    the data type of the result is computed and recorded in it,
7666    warnings are generated if arg data types are invalid,
7667    special handling for addition and subtraction of pointers is known,
7668    and some optimization is done (operations on narrow ints
7669    are done in the narrower type when that gives the same result).
7670    Constant folding is also done before the result is returned.
7671
7672    Note that the operands will never have enumeral types, or function
7673    or array types, because either they will have the default conversions
7674    performed or they have both just been converted to some other type in which
7675    the arithmetic is to be done.  */
7676
7677 tree
7678 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7679                  int convert_p)
7680 {
7681   tree type0, type1;
7682   enum tree_code code0, code1;
7683   tree op0, op1;
7684   const char *invalid_op_diag;
7685
7686   /* Expression code to give to the expression when it is built.
7687      Normally this is CODE, which is what the caller asked for,
7688      but in some special cases we change it.  */
7689   enum tree_code resultcode = code;
7690
7691   /* Data type in which the computation is to be performed.
7692      In the simplest cases this is the common type of the arguments.  */
7693   tree result_type = NULL;
7694
7695   /* Nonzero means operands have already been type-converted
7696      in whatever way is necessary.
7697      Zero means they need to be converted to RESULT_TYPE.  */
7698   int converted = 0;
7699
7700   /* Nonzero means create the expression with this type, rather than
7701      RESULT_TYPE.  */
7702   tree build_type = 0;
7703
7704   /* Nonzero means after finally constructing the expression
7705      convert it to this type.  */
7706   tree final_type = 0;
7707
7708   /* Nonzero if this is an operation like MIN or MAX which can
7709      safely be computed in short if both args are promoted shorts.
7710      Also implies COMMON.
7711      -1 indicates a bitwise operation; this makes a difference
7712      in the exact conditions for when it is safe to do the operation
7713      in a narrower mode.  */
7714   int shorten = 0;
7715
7716   /* Nonzero if this is a comparison operation;
7717      if both args are promoted shorts, compare the original shorts.
7718      Also implies COMMON.  */
7719   int short_compare = 0;
7720
7721   /* Nonzero if this is a right-shift operation, which can be computed on the
7722      original short and then promoted if the operand is a promoted short.  */
7723   int short_shift = 0;
7724
7725   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7726   int common = 0;
7727
7728   /* True means types are compatible as far as ObjC is concerned.  */
7729   bool objc_ok;
7730
7731   if (convert_p)
7732     {
7733       op0 = default_conversion (orig_op0);
7734       op1 = default_conversion (orig_op1);
7735     }
7736   else
7737     {
7738       op0 = orig_op0;
7739       op1 = orig_op1;
7740     }
7741
7742   type0 = TREE_TYPE (op0);
7743   type1 = TREE_TYPE (op1);
7744
7745   /* The expression codes of the data types of the arguments tell us
7746      whether the arguments are integers, floating, pointers, etc.  */
7747   code0 = TREE_CODE (type0);
7748   code1 = TREE_CODE (type1);
7749
7750   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7751   STRIP_TYPE_NOPS (op0);
7752   STRIP_TYPE_NOPS (op1);
7753
7754   /* If an error was already reported for one of the arguments,
7755      avoid reporting another error.  */
7756
7757   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7758     return error_mark_node;
7759
7760   if ((invalid_op_diag
7761        = targetm.invalid_binary_op (code, type0, type1)))
7762     {
7763       error (invalid_op_diag);
7764       return error_mark_node;
7765     }
7766
7767   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7768
7769   switch (code)
7770     {
7771     case PLUS_EXPR:
7772       /* Handle the pointer + int case.  */
7773       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7774         return pointer_int_sum (PLUS_EXPR, op0, op1);
7775       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7776         return pointer_int_sum (PLUS_EXPR, op1, op0);
7777       else
7778         common = 1;
7779       break;
7780
7781     case MINUS_EXPR:
7782       /* Subtraction of two similar pointers.
7783          We must subtract them as integers, then divide by object size.  */
7784       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7785           && comp_target_types (type0, type1))
7786         return pointer_diff (op0, op1);
7787       /* Handle pointer minus int.  Just like pointer plus int.  */
7788       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7789         return pointer_int_sum (MINUS_EXPR, op0, op1);
7790       else
7791         common = 1;
7792       break;
7793
7794     case MULT_EXPR:
7795       common = 1;
7796       break;
7797
7798     case TRUNC_DIV_EXPR:
7799     case CEIL_DIV_EXPR:
7800     case FLOOR_DIV_EXPR:
7801     case ROUND_DIV_EXPR:
7802     case EXACT_DIV_EXPR:
7803       /* Floating point division by zero is a legitimate way to obtain
7804          infinities and NaNs.  */
7805       if (skip_evaluation == 0 && integer_zerop (op1))
7806         warning (OPT_Wdiv_by_zero, "division by zero");
7807
7808       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7809            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7810           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7811               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7812         {
7813           enum tree_code tcode0 = code0, tcode1 = code1;
7814
7815           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7816             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7817           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7818             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7819
7820           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7821             resultcode = RDIV_EXPR;
7822           else
7823             /* Although it would be tempting to shorten always here, that
7824                loses on some targets, since the modulo instruction is
7825                undefined if the quotient can't be represented in the
7826                computation mode.  We shorten only if unsigned or if
7827                dividing by something we know != -1.  */
7828             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7829                        || (TREE_CODE (op1) == INTEGER_CST
7830                            && !integer_all_onesp (op1)));
7831           common = 1;
7832         }
7833       break;
7834
7835     case BIT_AND_EXPR:
7836     case BIT_IOR_EXPR:
7837     case BIT_XOR_EXPR:
7838       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7839         shorten = -1;
7840       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7841         common = 1;
7842       break;
7843
7844     case TRUNC_MOD_EXPR:
7845     case FLOOR_MOD_EXPR:
7846       if (skip_evaluation == 0 && integer_zerop (op1))
7847         warning (OPT_Wdiv_by_zero, "division by zero");
7848
7849       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7850         {
7851           /* Although it would be tempting to shorten always here, that loses
7852              on some targets, since the modulo instruction is undefined if the
7853              quotient can't be represented in the computation mode.  We shorten
7854              only if unsigned or if dividing by something we know != -1.  */
7855           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7856                      || (TREE_CODE (op1) == INTEGER_CST
7857                          && !integer_all_onesp (op1)));
7858           common = 1;
7859         }
7860       break;
7861
7862     case TRUTH_ANDIF_EXPR:
7863     case TRUTH_ORIF_EXPR:
7864     case TRUTH_AND_EXPR:
7865     case TRUTH_OR_EXPR:
7866     case TRUTH_XOR_EXPR:
7867       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7868            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7869           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7870               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7871         {
7872           /* Result of these operations is always an int,
7873              but that does not mean the operands should be
7874              converted to ints!  */
7875           result_type = integer_type_node;
7876           op0 = c_common_truthvalue_conversion (op0);
7877           op1 = c_common_truthvalue_conversion (op1);
7878           converted = 1;
7879         }
7880       break;
7881
7882       /* Shift operations: result has same type as first operand;
7883          always convert second operand to int.
7884          Also set SHORT_SHIFT if shifting rightward.  */
7885
7886     case RSHIFT_EXPR:
7887       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7888         {
7889           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7890             {
7891               if (tree_int_cst_sgn (op1) < 0)
7892                 warning (0, "right shift count is negative");
7893               else
7894                 {
7895                   if (!integer_zerop (op1))
7896                     short_shift = 1;
7897
7898                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7899                     warning (0, "right shift count >= width of type");
7900                 }
7901             }
7902
7903           /* Use the type of the value to be shifted.  */
7904           result_type = type0;
7905           /* Convert the shift-count to an integer, regardless of size
7906              of value being shifted.  */
7907           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7908             op1 = convert (integer_type_node, op1);
7909           /* Avoid converting op1 to result_type later.  */
7910           converted = 1;
7911         }
7912       break;
7913
7914     case LSHIFT_EXPR:
7915       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7916         {
7917           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7918             {
7919               if (tree_int_cst_sgn (op1) < 0)
7920                 warning (0, "left shift count is negative");
7921
7922               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7923                 warning (0, "left shift count >= width of type");
7924             }
7925
7926           /* Use the type of the value to be shifted.  */
7927           result_type = type0;
7928           /* Convert the shift-count to an integer, regardless of size
7929              of value being shifted.  */
7930           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7931             op1 = convert (integer_type_node, op1);
7932           /* Avoid converting op1 to result_type later.  */
7933           converted = 1;
7934         }
7935       break;
7936
7937     case EQ_EXPR:
7938     case NE_EXPR:
7939       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7940         warning (OPT_Wfloat_equal,
7941                  "comparing floating point with == or != is unsafe");
7942       /* Result of comparison is always int,
7943          but don't convert the args to int!  */
7944       build_type = integer_type_node;
7945       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7946            || code0 == COMPLEX_TYPE)
7947           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7948               || code1 == COMPLEX_TYPE))
7949         short_compare = 1;
7950       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7951         {
7952           tree tt0 = TREE_TYPE (type0);
7953           tree tt1 = TREE_TYPE (type1);
7954           /* Anything compares with void *.  void * compares with anything.
7955              Otherwise, the targets must be compatible
7956              and both must be object or both incomplete.  */
7957           if (comp_target_types (type0, type1))
7958             result_type = common_pointer_type (type0, type1);
7959           else if (VOID_TYPE_P (tt0))
7960             {
7961               /* op0 != orig_op0 detects the case of something
7962                  whose value is 0 but which isn't a valid null ptr const.  */
7963               if (pedantic && !null_pointer_constant_p (orig_op0)
7964                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7965                 pedwarn ("ISO C forbids comparison of %<void *%>"
7966                          " with function pointer");
7967             }
7968           else if (VOID_TYPE_P (tt1))
7969             {
7970               if (pedantic && !null_pointer_constant_p (orig_op1)
7971                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7972                 pedwarn ("ISO C forbids comparison of %<void *%>"
7973                          " with function pointer");
7974             }
7975           else
7976             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7977             if (!objc_ok)
7978               pedwarn ("comparison of distinct pointer types lacks a cast");
7979
7980           if (result_type == NULL_TREE)
7981             result_type = ptr_type_node;
7982         }
7983       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
7984         {
7985           if (TREE_CODE (op0) == ADDR_EXPR
7986               && DECL_P (TREE_OPERAND (op0, 0))
7987               && !DECL_WEAK (TREE_OPERAND (op0, 0)))
7988             warning (OPT_Walways_true, "the address of %qD will never be NULL",
7989                      TREE_OPERAND (op0, 0));
7990           result_type = type0;
7991         }
7992       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
7993         {
7994           if (TREE_CODE (op1) == ADDR_EXPR
7995               && DECL_P (TREE_OPERAND (op1, 0))
7996               && !DECL_WEAK (TREE_OPERAND (op1, 0)))
7997             warning (OPT_Walways_true, "the address of %qD will never be NULL",
7998                      TREE_OPERAND (op1, 0));
7999           result_type = type1;
8000         }
8001       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8002         {
8003           result_type = type0;
8004           pedwarn ("comparison between pointer and integer");
8005         }
8006       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8007         {
8008           result_type = type1;
8009           pedwarn ("comparison between pointer and integer");
8010         }
8011       break;
8012
8013     case LE_EXPR:
8014     case GE_EXPR:
8015     case LT_EXPR:
8016     case GT_EXPR:
8017       build_type = integer_type_node;
8018       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
8019           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
8020         short_compare = 1;
8021       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8022         {
8023           if (comp_target_types (type0, type1))
8024             {
8025               result_type = common_pointer_type (type0, type1);
8026               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8027                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8028                 pedwarn ("comparison of complete and incomplete pointers");
8029               else if (pedantic
8030                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8031                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8032             }
8033           else
8034             {
8035               result_type = ptr_type_node;
8036               pedwarn ("comparison of distinct pointer types lacks a cast");
8037             }
8038         }
8039       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8040         {
8041           result_type = type0;
8042           if (pedantic || extra_warnings)
8043             pedwarn ("ordered comparison of pointer with integer zero");
8044         }
8045       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8046         {
8047           result_type = type1;
8048           if (pedantic)
8049             pedwarn ("ordered comparison of pointer with integer zero");
8050         }
8051       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8052         {
8053           result_type = type0;
8054           pedwarn ("comparison between pointer and integer");
8055         }
8056       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8057         {
8058           result_type = type1;
8059           pedwarn ("comparison between pointer and integer");
8060         }
8061       break;
8062
8063     default:
8064       gcc_unreachable ();
8065     }
8066
8067   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8068     return error_mark_node;
8069
8070   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8071       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8072           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8073                                                     TREE_TYPE (type1))))
8074     {
8075       binary_op_error (code);
8076       return error_mark_node;
8077     }
8078
8079   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8080        || code0 == VECTOR_TYPE)
8081       &&
8082       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8083        || code1 == VECTOR_TYPE))
8084     {
8085       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8086
8087       if (shorten || common || short_compare)
8088         result_type = c_common_type (type0, type1);
8089
8090       /* For certain operations (which identify themselves by shorten != 0)
8091          if both args were extended from the same smaller type,
8092          do the arithmetic in that type and then extend.
8093
8094          shorten !=0 and !=1 indicates a bitwise operation.
8095          For them, this optimization is safe only if
8096          both args are zero-extended or both are sign-extended.
8097          Otherwise, we might change the result.
8098          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8099          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8100
8101       if (shorten && none_complex)
8102         {
8103           int unsigned0, unsigned1;
8104           tree arg0, arg1;
8105           int uns;
8106           tree type;
8107
8108           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8109              excessive narrowing when we call get_narrower below.  For
8110              example, suppose that OP0 is of unsigned int extended
8111              from signed char and that RESULT_TYPE is long long int.
8112              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8113              like
8114
8115                (long long int) (unsigned int) signed_char
8116
8117              which get_narrower would narrow down to
8118
8119                (unsigned int) signed char
8120
8121              If we do not cast OP0 first, get_narrower would return
8122              signed_char, which is inconsistent with the case of the
8123              explicit cast.  */
8124           op0 = convert (result_type, op0);
8125           op1 = convert (result_type, op1);
8126
8127           arg0 = get_narrower (op0, &unsigned0);
8128           arg1 = get_narrower (op1, &unsigned1);
8129
8130           /* UNS is 1 if the operation to be done is an unsigned one.  */
8131           uns = TYPE_UNSIGNED (result_type);
8132
8133           final_type = result_type;
8134
8135           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8136              but it *requires* conversion to FINAL_TYPE.  */
8137
8138           if ((TYPE_PRECISION (TREE_TYPE (op0))
8139                == TYPE_PRECISION (TREE_TYPE (arg0)))
8140               && TREE_TYPE (op0) != final_type)
8141             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8142           if ((TYPE_PRECISION (TREE_TYPE (op1))
8143                == TYPE_PRECISION (TREE_TYPE (arg1)))
8144               && TREE_TYPE (op1) != final_type)
8145             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8146
8147           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8148
8149           /* For bitwise operations, signedness of nominal type
8150              does not matter.  Consider only how operands were extended.  */
8151           if (shorten == -1)
8152             uns = unsigned0;
8153
8154           /* Note that in all three cases below we refrain from optimizing
8155              an unsigned operation on sign-extended args.
8156              That would not be valid.  */
8157
8158           /* Both args variable: if both extended in same way
8159              from same width, do it in that width.
8160              Do it unsigned if args were zero-extended.  */
8161           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8162                < TYPE_PRECISION (result_type))
8163               && (TYPE_PRECISION (TREE_TYPE (arg1))
8164                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8165               && unsigned0 == unsigned1
8166               && (unsigned0 || !uns))
8167             result_type
8168               = c_common_signed_or_unsigned_type
8169               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8170           else if (TREE_CODE (arg0) == INTEGER_CST
8171                    && (unsigned1 || !uns)
8172                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8173                        < TYPE_PRECISION (result_type))
8174                    && (type
8175                        = c_common_signed_or_unsigned_type (unsigned1,
8176                                                            TREE_TYPE (arg1)),
8177                        int_fits_type_p (arg0, type)))
8178             result_type = type;
8179           else if (TREE_CODE (arg1) == INTEGER_CST
8180                    && (unsigned0 || !uns)
8181                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8182                        < TYPE_PRECISION (result_type))
8183                    && (type
8184                        = c_common_signed_or_unsigned_type (unsigned0,
8185                                                            TREE_TYPE (arg0)),
8186                        int_fits_type_p (arg1, type)))
8187             result_type = type;
8188         }
8189
8190       /* Shifts can be shortened if shifting right.  */
8191
8192       if (short_shift)
8193         {
8194           int unsigned_arg;
8195           tree arg0 = get_narrower (op0, &unsigned_arg);
8196
8197           final_type = result_type;
8198
8199           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8200             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8201
8202           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8203               /* We can shorten only if the shift count is less than the
8204                  number of bits in the smaller type size.  */
8205               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8206               /* We cannot drop an unsigned shift after sign-extension.  */
8207               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8208             {
8209               /* Do an unsigned shift if the operand was zero-extended.  */
8210               result_type
8211                 = c_common_signed_or_unsigned_type (unsigned_arg,
8212                                                     TREE_TYPE (arg0));
8213               /* Convert value-to-be-shifted to that type.  */
8214               if (TREE_TYPE (op0) != result_type)
8215                 op0 = convert (result_type, op0);
8216               converted = 1;
8217             }
8218         }
8219
8220       /* Comparison operations are shortened too but differently.
8221          They identify themselves by setting short_compare = 1.  */
8222
8223       if (short_compare)
8224         {
8225           /* Don't write &op0, etc., because that would prevent op0
8226              from being kept in a register.
8227              Instead, make copies of the our local variables and
8228              pass the copies by reference, then copy them back afterward.  */
8229           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8230           enum tree_code xresultcode = resultcode;
8231           tree val
8232             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8233
8234           if (val != 0)
8235             return val;
8236
8237           op0 = xop0, op1 = xop1;
8238           converted = 1;
8239           resultcode = xresultcode;
8240
8241           if (warn_sign_compare && skip_evaluation == 0)
8242             {
8243               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8244               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8245               int unsignedp0, unsignedp1;
8246               tree primop0 = get_narrower (op0, &unsignedp0);
8247               tree primop1 = get_narrower (op1, &unsignedp1);
8248
8249               xop0 = orig_op0;
8250               xop1 = orig_op1;
8251               STRIP_TYPE_NOPS (xop0);
8252               STRIP_TYPE_NOPS (xop1);
8253
8254               /* Give warnings for comparisons between signed and unsigned
8255                  quantities that may fail.
8256
8257                  Do the checking based on the original operand trees, so that
8258                  casts will be considered, but default promotions won't be.
8259
8260                  Do not warn if the comparison is being done in a signed type,
8261                  since the signed type will only be chosen if it can represent
8262                  all the values of the unsigned type.  */
8263               if (!TYPE_UNSIGNED (result_type))
8264                 /* OK */;
8265               /* Do not warn if both operands are the same signedness.  */
8266               else if (op0_signed == op1_signed)
8267                 /* OK */;
8268               else
8269                 {
8270                   tree sop, uop;
8271
8272                   if (op0_signed)
8273                     sop = xop0, uop = xop1;
8274                   else
8275                     sop = xop1, uop = xop0;
8276
8277                   /* Do not warn if the signed quantity is an
8278                      unsuffixed integer literal (or some static
8279                      constant expression involving such literals or a
8280                      conditional expression involving such literals)
8281                      and it is non-negative.  */
8282                   if (tree_expr_nonnegative_p (sop))
8283                     /* OK */;
8284                   /* Do not warn if the comparison is an equality operation,
8285                      the unsigned quantity is an integral constant, and it
8286                      would fit in the result if the result were signed.  */
8287                   else if (TREE_CODE (uop) == INTEGER_CST
8288                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8289                            && int_fits_type_p
8290                            (uop, c_common_signed_type (result_type)))
8291                     /* OK */;
8292                   /* Do not warn if the unsigned quantity is an enumeration
8293                      constant and its maximum value would fit in the result
8294                      if the result were signed.  */
8295                   else if (TREE_CODE (uop) == INTEGER_CST
8296                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8297                            && int_fits_type_p
8298                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8299                             c_common_signed_type (result_type)))
8300                     /* OK */;
8301                   else
8302                     warning (0, "comparison between signed and unsigned");
8303                 }
8304
8305               /* Warn if two unsigned values are being compared in a size
8306                  larger than their original size, and one (and only one) is the
8307                  result of a `~' operator.  This comparison will always fail.
8308
8309                  Also warn if one operand is a constant, and the constant
8310                  does not have all bits set that are set in the ~ operand
8311                  when it is extended.  */
8312
8313               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8314                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8315                 {
8316                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8317                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8318                                             &unsignedp0);
8319                   else
8320                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8321                                             &unsignedp1);
8322
8323                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8324                     {
8325                       tree primop;
8326                       HOST_WIDE_INT constant, mask;
8327                       int unsignedp, bits;
8328
8329                       if (host_integerp (primop0, 0))
8330                         {
8331                           primop = primop1;
8332                           unsignedp = unsignedp1;
8333                           constant = tree_low_cst (primop0, 0);
8334                         }
8335                       else
8336                         {
8337                           primop = primop0;
8338                           unsignedp = unsignedp0;
8339                           constant = tree_low_cst (primop1, 0);
8340                         }
8341
8342                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8343                       if (bits < TYPE_PRECISION (result_type)
8344                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8345                         {
8346                           mask = (~(HOST_WIDE_INT) 0) << bits;
8347                           if ((mask & constant) != mask)
8348                             warning (0, "comparison of promoted ~unsigned with constant");
8349                         }
8350                     }
8351                   else if (unsignedp0 && unsignedp1
8352                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8353                                < TYPE_PRECISION (result_type))
8354                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8355                                < TYPE_PRECISION (result_type)))
8356                     warning (0, "comparison of promoted ~unsigned with unsigned");
8357                 }
8358             }
8359         }
8360     }
8361
8362   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8363      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8364      Then the expression will be built.
8365      It will be given type FINAL_TYPE if that is nonzero;
8366      otherwise, it will be given type RESULT_TYPE.  */
8367
8368   if (!result_type)
8369     {
8370       binary_op_error (code);
8371       return error_mark_node;
8372     }
8373
8374   if (!converted)
8375     {
8376       if (TREE_TYPE (op0) != result_type)
8377         op0 = convert (result_type, op0);
8378       if (TREE_TYPE (op1) != result_type)
8379         op1 = convert (result_type, op1);
8380
8381       /* This can happen if one operand has a vector type, and the other
8382          has a different type.  */
8383       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8384         return error_mark_node;
8385     }
8386
8387   if (build_type == NULL_TREE)
8388     build_type = result_type;
8389
8390   {
8391     /* Treat expressions in initializers specially as they can't trap.  */
8392     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8393                                                                     build_type,
8394                                                                     op0, op1)
8395                                          : fold_build2 (resultcode, build_type,
8396                                                         op0, op1);
8397
8398     if (final_type != 0)
8399       result = convert (final_type, result);
8400     return result;
8401   }
8402 }
8403
8404
8405 /* Convert EXPR to be a truth-value, validating its type for this
8406    purpose.  */
8407
8408 tree
8409 c_objc_common_truthvalue_conversion (tree expr)
8410 {
8411   switch (TREE_CODE (TREE_TYPE (expr)))
8412     {
8413     case ARRAY_TYPE:
8414       error ("used array that cannot be converted to pointer where scalar is required");
8415       return error_mark_node;
8416
8417     case RECORD_TYPE:
8418       error ("used struct type value where scalar is required");
8419       return error_mark_node;
8420
8421     case UNION_TYPE:
8422       error ("used union type value where scalar is required");
8423       return error_mark_node;
8424
8425     case FUNCTION_TYPE:
8426       gcc_unreachable ();
8427
8428     default:
8429       break;
8430     }
8431
8432   /* ??? Should we also give an error for void and vectors rather than
8433      leaving those to give errors later?  */
8434   return c_common_truthvalue_conversion (expr);
8435 }
8436 \f
8437
8438 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8439    required.  */
8440
8441 tree
8442 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8443                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8444 {
8445   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8446     {
8447       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8448       /* Executing a compound literal inside a function reinitializes
8449          it.  */
8450       if (!TREE_STATIC (decl))
8451         *se = true;
8452       return decl;
8453     }
8454   else
8455     return expr;
8456 }
8457
8458 \f
8459 /* Like c_begin_compound_stmt, except force the retension of the BLOCK.  */
8460
8461 tree
8462 c_begin_omp_parallel (void)
8463 {
8464   tree block;
8465
8466   keep_next_level ();
8467   block = c_begin_compound_stmt (true);
8468
8469   return block;
8470 }
8471
8472 tree
8473 c_finish_omp_parallel (tree clauses, tree block)
8474 {
8475   tree stmt;
8476
8477   block = c_end_compound_stmt (block, true);
8478
8479   stmt = make_node (OMP_PARALLEL);
8480   TREE_TYPE (stmt) = void_type_node;
8481   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8482   OMP_PARALLEL_BODY (stmt) = block;
8483
8484   return add_stmt (stmt);
8485 }
8486
8487 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8488    Remove any elements from the list that are invalid.  */
8489
8490 tree
8491 c_finish_omp_clauses (tree clauses)
8492 {
8493   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8494   tree c, t, *pc = &clauses;
8495   const char *name;
8496
8497   bitmap_obstack_initialize (NULL);
8498   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8499   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8500   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8501
8502   for (pc = &clauses, c = clauses; c ; c = *pc)
8503     {
8504       bool remove = false;
8505       bool need_complete = false;
8506       bool need_implicitly_determined = false;
8507
8508       switch (OMP_CLAUSE_CODE (c))
8509         {
8510         case OMP_CLAUSE_SHARED:
8511           name = "shared";
8512           need_implicitly_determined = true;
8513           goto check_dup_generic;
8514
8515         case OMP_CLAUSE_PRIVATE:
8516           name = "private";
8517           need_complete = true;
8518           need_implicitly_determined = true;
8519           goto check_dup_generic;
8520
8521         case OMP_CLAUSE_REDUCTION:
8522           name = "reduction";
8523           need_implicitly_determined = true;
8524           t = OMP_CLAUSE_DECL (c);
8525           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8526               || POINTER_TYPE_P (TREE_TYPE (t)))
8527             {
8528               error ("%qE has invalid type for %<reduction%>", t);
8529               remove = true;
8530             }
8531           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8532             {
8533               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8534               const char *r_name = NULL;
8535
8536               switch (r_code)
8537                 {
8538                 case PLUS_EXPR:
8539                 case MULT_EXPR:
8540                 case MINUS_EXPR:
8541                   break;
8542                 case BIT_AND_EXPR:
8543                   r_name = "&";
8544                   break;
8545                 case BIT_XOR_EXPR:
8546                   r_name = "^";
8547                   break;
8548                 case BIT_IOR_EXPR:
8549                   r_name = "|";
8550                   break;
8551                 case TRUTH_ANDIF_EXPR:
8552                   r_name = "&&";
8553                   break;
8554                 case TRUTH_ORIF_EXPR:
8555                   r_name = "||";
8556                   break;
8557                 default:
8558                   gcc_unreachable ();
8559                 }
8560               if (r_name)
8561                 {
8562                   error ("%qE has invalid type for %<reduction(%s)%>",
8563                          t, r_name);
8564                   remove = true;
8565                 }
8566             }
8567           goto check_dup_generic;
8568
8569         case OMP_CLAUSE_COPYPRIVATE:
8570           name = "copyprivate";
8571           goto check_dup_generic;
8572
8573         case OMP_CLAUSE_COPYIN:
8574           name = "copyin";
8575           t = OMP_CLAUSE_DECL (c);
8576           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8577             {
8578               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8579               remove = true;
8580             }
8581           goto check_dup_generic;
8582
8583         check_dup_generic:
8584           t = OMP_CLAUSE_DECL (c);
8585           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8586             {
8587               error ("%qE is not a variable in clause %qs", t, name);
8588               remove = true;
8589             }
8590           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8591                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8592                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8593             {
8594               error ("%qE appears more than once in data clauses", t);
8595               remove = true;
8596             }
8597           else
8598             bitmap_set_bit (&generic_head, DECL_UID (t));
8599           break;
8600
8601         case OMP_CLAUSE_FIRSTPRIVATE:
8602           name = "firstprivate";
8603           t = OMP_CLAUSE_DECL (c);
8604           need_complete = true;
8605           need_implicitly_determined = true;
8606           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8607             {
8608               error ("%qE is not a variable in clause %<firstprivate%>", t);
8609               remove = true;
8610             }
8611           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8612                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8613             {
8614               error ("%qE appears more than once in data clauses", t);
8615               remove = true;
8616             }
8617           else
8618             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8619           break;
8620
8621         case OMP_CLAUSE_LASTPRIVATE:
8622           name = "lastprivate";
8623           t = OMP_CLAUSE_DECL (c);
8624           need_complete = true;
8625           need_implicitly_determined = true;
8626           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8627             {
8628               error ("%qE is not a variable in clause %<lastprivate%>", t);
8629               remove = true;
8630             }
8631           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8632                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8633             {
8634               error ("%qE appears more than once in data clauses", t);
8635               remove = true;
8636             }
8637           else
8638             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8639           break;
8640
8641         case OMP_CLAUSE_IF:
8642         case OMP_CLAUSE_NUM_THREADS:
8643         case OMP_CLAUSE_SCHEDULE:
8644         case OMP_CLAUSE_NOWAIT:
8645         case OMP_CLAUSE_ORDERED:
8646         case OMP_CLAUSE_DEFAULT:
8647           pc = &OMP_CLAUSE_CHAIN (c);
8648           continue;
8649
8650         default:
8651           gcc_unreachable ();
8652         }
8653
8654       if (!remove)
8655         {
8656           t = OMP_CLAUSE_DECL (c);
8657
8658           if (need_complete)
8659             {
8660               t = require_complete_type (t);
8661               if (t == error_mark_node)
8662                 remove = true;
8663             }
8664
8665           if (need_implicitly_determined)
8666             {
8667               const char *share_name = NULL;
8668
8669               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8670                 share_name = "threadprivate";
8671               else switch (c_omp_predetermined_sharing (t))
8672                 {
8673                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8674                   break;
8675                 case OMP_CLAUSE_DEFAULT_SHARED:
8676                   share_name = "shared";
8677                   break;
8678                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8679                   share_name = "private";
8680                   break;
8681                 default:
8682                   gcc_unreachable ();
8683                 }
8684               if (share_name)
8685                 {
8686                   error ("%qE is predetermined %qs for %qs",
8687                          t, share_name, name);
8688                   remove = true;
8689                 }
8690             }
8691         }
8692
8693       if (remove)
8694         *pc = OMP_CLAUSE_CHAIN (c);
8695       else
8696         pc = &OMP_CLAUSE_CHAIN (c);
8697     }
8698
8699   bitmap_obstack_release (NULL);
8700   return clauses;
8701 }