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 int spelling_length (void);
  94 static char *print_spelling (char *);
  95 static void warning_init (const char *);
  96 static tree digest_init (tree, tree, bool, int);
  97 static void output_init_element (tree, bool, tree, tree, int);
  98 static void output_pending_init_elements (int);
  99 static int set_designator (int);
 100 static void push_range_stack (tree);
 101 static void add_pending_init (tree, tree);
 102 static void set_nonincremental_init (void);
 103 static void set_nonincremental_init_from_string (tree);
 104 static tree find_init_member (tree);
 105 static void readonly_error (tree, enum lvalue_use);
 106 static int lvalue_or_else (tree, enum lvalue_use);
 107 static int lvalue_p (tree);
 108 static void record_maybe_used_decl (tree);
 109 static int comptypes_internal (tree, tree);
 110 \f
 111 /* Return true if EXP is a null pointer constant, false otherwise.  */
 112
 113 static bool
 114 null_pointer_constant_p (tree expr)
 115 {
 116   /* This should really operate on c_expr structures, but they aren't
 117      yet available everywhere required.  */
 118   tree type = TREE_TYPE (expr);
 119   return (TREE_CODE (expr) == INTEGER_CST
 120           && !TREE_CONSTANT_OVERFLOW (expr)
 121           && integer_zerop (expr)
 122           && (INTEGRAL_TYPE_P (type)
 123               || (TREE_CODE (type) == POINTER_TYPE
 124                   && VOID_TYPE_P (TREE_TYPE (type))
 125                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 126 }
 127 \f/* This is a cache to hold if two types are compatible or not.  */
 128
 129 struct tagged_tu_seen_cache {
 130   const struct tagged_tu_seen_cache * next;
 131   tree t1;
 132   tree t2;
 133   /* The return value of tagged_types_tu_compatible_p if we had seen
 134      these two types already.  */
 135   int val;
 136 };
 137
 138 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 139 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 140
 141 /* Do `exp = require_complete_type (exp);' to make sure exp
 142    does not have an incomplete type.  (That includes void types.)  */
 143
 144 tree
 145 require_complete_type (tree value)
 146 {
 147   tree type = TREE_TYPE (value);
 148
 149   if (value == error_mark_node || type == error_mark_node)
 150     return error_mark_node;
 151
 152   /* First, detect a valid value with a complete type.  */
 153   if (COMPLETE_TYPE_P (type))
 154     return value;
 155
 156   c_incomplete_type_error (value, type);
 157   return error_mark_node;
 158 }
 159
 160 /* Print an error message for invalid use of an incomplete type.
 161    VALUE is the expression that was used (or 0 if that isn't known)
 162    and TYPE is the type that was invalid.  */
 163
 164 void
 165 c_incomplete_type_error (tree value, tree type)
 166 {
 167   const char *type_code_string;
 168
 169   /* Avoid duplicate error message.  */
 170   if (TREE_CODE (type) == ERROR_MARK)
 171     return;
 172
 173   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 174                      || TREE_CODE (value) == PARM_DECL))
 175     error ("%qD has an incomplete type", value);
 176   else
 177     {
 178     retry:
 179       /* We must print an error message.  Be clever about what it says.  */
 180
 181       switch (TREE_CODE (type))
 182         {
 183         case RECORD_TYPE:
 184           type_code_string = "struct";
 185           break;
 186
 187         case UNION_TYPE:
 188           type_code_string = "union";
 189           break;
 190
 191         case ENUMERAL_TYPE:
 192           type_code_string = "enum";
 193           break;
 194
 195         case VOID_TYPE:
 196           error ("invalid use of void expression");
 197           return;
 198
 199         case ARRAY_TYPE:
 200           if (TYPE_DOMAIN (type))
 201             {
 202               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 203                 {
 204                   error ("invalid use of flexible array member");
 205                   return;
 206                 }
 207               type = TREE_TYPE (type);
 208               goto retry;
 209             }
 210           error ("invalid use of array with unspecified bounds");
 211           return;
 212
 213         default:
 214           gcc_unreachable ();
 215         }
 216
 217       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 218         error ("invalid use of undefined type %<%s %E%>",
 219                type_code_string, TYPE_NAME (type));
 220       else
 221         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 222         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 223     }
 224 }
 225
 226 /* Given a type, apply default promotions wrt unnamed function
 227    arguments and return the new type.  */
 228
 229 tree
 230 c_type_promotes_to (tree type)
 231 {
 232   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 233     return double_type_node;
 234
 235   if (c_promoting_integer_type_p (type))
 236     {
 237       /* Preserve unsignedness if not really getting any wider.  */
 238       if (TYPE_UNSIGNED (type)
 239           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 240         return unsigned_type_node;
 241       return integer_type_node;
 242     }
 243
 244   return type;
 245 }
 246
 247 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 248    as well as those of TYPE.  */
 249
 250 static tree
 251 qualify_type (tree type, tree like)
 252 {
 253   return c_build_qualified_type (type,
 254                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 255 }
 256 \f
 257 /* Return the composite type of two compatible types.
 258
 259    We assume that comptypes has already been done and returned
 260    nonzero; if that isn't so, this may crash.  In particular, we
 261    assume that qualifiers match.  */
 262
 263 tree
 264 composite_type (tree t1, tree t2)
 265 {
 266   enum tree_code code1;
 267   enum tree_code code2;
 268   tree attributes;
 269
 270   /* Save time if the two types are the same.  */
 271
 272   if (t1 == t2) return t1;
 273
 274   /* If one type is nonsense, use the other.  */
 275   if (t1 == error_mark_node)
 276     return t2;
 277   if (t2 == error_mark_node)
 278     return t1;
 279
 280   code1 = TREE_CODE (t1);
 281   code2 = TREE_CODE (t2);
 282
 283   /* Merge the attributes.  */
 284   attributes = targetm.merge_type_attributes (t1, t2);
 285
 286   /* If one is an enumerated type and the other is the compatible
 287      integer type, the composite type might be either of the two
 288      (DR#013 question 3).  For consistency, use the enumerated type as
 289      the composite type.  */
 290
 291   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 292     return t1;
 293   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 294     return t2;
 295
 296   gcc_assert (code1 == code2);
 297
 298   switch (code1)
 299     {
 300     case POINTER_TYPE:
 301       /* For two pointers, do this recursively on the target type.  */
 302       {
 303         tree pointed_to_1 = TREE_TYPE (t1);
 304         tree pointed_to_2 = TREE_TYPE (t2);
 305         tree target = composite_type (pointed_to_1, pointed_to_2);
 306         t1 = build_pointer_type (target);
 307         t1 = build_type_attribute_variant (t1, attributes);
 308         return qualify_type (t1, t2);
 309       }
 310
 311     case ARRAY_TYPE:
 312       {
 313         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 314         int quals;
 315         tree unqual_elt;
 316         tree d1 = TYPE_DOMAIN (t1);
 317         tree d2 = TYPE_DOMAIN (t2);
 318         bool d1_variable, d2_variable;
 319         bool d1_zero, d2_zero;
 320
 321         /* We should not have any type quals on arrays at all.  */
 322         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 323
 324         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 325         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 326
 327         d1_variable = (!d1_zero
 328                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 329                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 330         d2_variable = (!d2_zero
 331                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 332                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 333
 334         /* Save space: see if the result is identical to one of the args.  */
 335         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 336             && (d2_variable || d2_zero || !d1_variable))
 337           return build_type_attribute_variant (t1, attributes);
 338         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 339             && (d1_variable || d1_zero || !d2_variable))
 340           return build_type_attribute_variant (t2, attributes);
 341
 342         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 343           return build_type_attribute_variant (t1, attributes);
 344         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 345           return build_type_attribute_variant (t2, attributes);
 346
 347         /* Merge the element types, and have a size if either arg has
 348            one.  We may have qualifiers on the element types.  To set
 349            up TYPE_MAIN_VARIANT correctly, we need to form the
 350            composite of the unqualified types and add the qualifiers
 351            back at the end.  */
 352         quals = TYPE_QUALS (strip_array_types (elt));
 353         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 354         t1 = build_array_type (unqual_elt,
 355                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 356                                              && (d2_variable
 357                                                  || d2_zero
 358                                                  || !d1_variable))
 359                                             ? t1
 360                                             : t2));
 361         t1 = c_build_qualified_type (t1, quals);
 362         return build_type_attribute_variant (t1, attributes);
 363       }
 364
 365     case FUNCTION_TYPE:
 366       /* Function types: prefer the one that specified arg types.
 367          If both do, merge the arg types.  Also merge the return types.  */
 368       {
 369         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 370         tree p1 = TYPE_ARG_TYPES (t1);
 371         tree p2 = TYPE_ARG_TYPES (t2);
 372         int len;
 373         tree newargs, n;
 374         int i;
 375
 376         /* Save space: see if the result is identical to one of the args.  */
 377         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 378           return build_type_attribute_variant (t1, attributes);
 379         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 380           return build_type_attribute_variant (t2, attributes);
 381
 382         /* Simple way if one arg fails to specify argument types.  */
 383         if (TYPE_ARG_TYPES (t1) == 0)
 384          {
 385             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 386             t1 = build_type_attribute_variant (t1, attributes);
 387             return qualify_type (t1, t2);
 388          }
 389         if (TYPE_ARG_TYPES (t2) == 0)
 390          {
 391            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 392            t1 = build_type_attribute_variant (t1, attributes);
 393            return qualify_type (t1, t2);
 394          }
 395
 396         /* If both args specify argument types, we must merge the two
 397            lists, argument by argument.  */
 398         /* Tell global_bindings_p to return false so that variable_size
 399            doesn't die on VLAs in parameter types.  */
 400         c_override_global_bindings_to_false = true;
 401
 402         len = list_length (p1);
 403         newargs = 0;
 404
 405         for (i = 0; i < len; i++)
 406           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 407
 408         n = newargs;
 409
 410         for (; p1;
 411              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 412           {
 413             /* A null type means arg type is not specified.
 414                Take whatever the other function type has.  */
 415             if (TREE_VALUE (p1) == 0)
 416               {
 417                 TREE_VALUE (n) = TREE_VALUE (p2);
 418                 goto parm_done;
 419               }
 420             if (TREE_VALUE (p2) == 0)
 421               {
 422                 TREE_VALUE (n) = TREE_VALUE (p1);
 423                 goto parm_done;
 424               }
 425
 426             /* Given  wait (union {union wait *u; int *i} *)
 427                and  wait (union wait *),
 428                prefer  union wait *  as type of parm.  */
 429             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 430                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 431               {
 432                 tree memb;
 433                 tree mv2 = TREE_VALUE (p2);
 434                 if (mv2 && mv2 != error_mark_node
 435                     && TREE_CODE (mv2) != ARRAY_TYPE)
 436                   mv2 = TYPE_MAIN_VARIANT (mv2);
 437                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 438                      memb; memb = TREE_CHAIN (memb))
 439                   {
 440                     tree mv3 = TREE_TYPE (memb);
 441                     if (mv3 && mv3 != error_mark_node
 442                         && TREE_CODE (mv3) != ARRAY_TYPE)
 443                       mv3 = TYPE_MAIN_VARIANT (mv3);
 444                     if (comptypes (mv3, mv2))
 445                       {
 446                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 447                                                          TREE_VALUE (p2));
 448                         if (pedantic)
 449                           pedwarn ("function types not truly compatible in ISO C");
 450                         goto parm_done;
 451                       }
 452                   }
 453               }
 454             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 455                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 456               {
 457                 tree memb;
 458                 tree mv1 = TREE_VALUE (p1);
 459                 if (mv1 && mv1 != error_mark_node
 460                     && TREE_CODE (mv1) != ARRAY_TYPE)
 461                   mv1 = TYPE_MAIN_VARIANT (mv1);
 462                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 463                      memb; memb = TREE_CHAIN (memb))
 464                   {
 465                     tree mv3 = TREE_TYPE (memb);
 466                     if (mv3 && mv3 != error_mark_node
 467                         && TREE_CODE (mv3) != ARRAY_TYPE)
 468                       mv3 = TYPE_MAIN_VARIANT (mv3);
 469                     if (comptypes (mv3, mv1))
 470                       {
 471                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 472                                                          TREE_VALUE (p1));
 473                         if (pedantic)
 474                           pedwarn ("function types not truly compatible in ISO C");
 475                         goto parm_done;
 476                       }
 477                   }
 478               }
 479             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 480           parm_done: ;
 481           }
 482
 483         c_override_global_bindings_to_false = false;
 484         t1 = build_function_type (valtype, newargs);
 485         t1 = qualify_type (t1, t2);
 486         /* ... falls through ...  */
 487       }
 488
 489     default:
 490       return build_type_attribute_variant (t1, attributes);
 491     }
 492
 493 }
 494
 495 /* Return the type of a conditional expression between pointers to
 496    possibly differently qualified versions of compatible types.
 497
 498    We assume that comp_target_types has already been done and returned
 499    nonzero; if that isn't so, this may crash.  */
 500
 501 static tree
 502 common_pointer_type (tree t1, tree t2)
 503 {
 504   tree attributes;
 505   tree pointed_to_1, mv1;
 506   tree pointed_to_2, mv2;
 507   tree target;
 508
 509   /* Save time if the two types are the same.  */
 510
 511   if (t1 == t2) return t1;
 512
 513   /* If one type is nonsense, use the other.  */
 514   if (t1 == error_mark_node)
 515     return t2;
 516   if (t2 == error_mark_node)
 517     return t1;
 518
 519   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 520               && TREE_CODE (t2) == POINTER_TYPE);
 521
 522   /* Merge the attributes.  */
 523   attributes = targetm.merge_type_attributes (t1, t2);
 524
 525   /* Find the composite type of the target types, and combine the
 526      qualifiers of the two types' targets.  Do not lose qualifiers on
 527      array element types by taking the TYPE_MAIN_VARIANT.  */
 528   mv1 = pointed_to_1 = TREE_TYPE (t1);
 529   mv2 = pointed_to_2 = TREE_TYPE (t2);
 530   if (TREE_CODE (mv1) != ARRAY_TYPE)
 531     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 532   if (TREE_CODE (mv2) != ARRAY_TYPE)
 533     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 534   target = composite_type (mv1, mv2);
 535   t1 = build_pointer_type (c_build_qualified_type
 536                            (target,
 537                             TYPE_QUALS (pointed_to_1) |
 538                             TYPE_QUALS (pointed_to_2)));
 539   return build_type_attribute_variant (t1, attributes);
 540 }
 541
 542 /* Return the common type for two arithmetic types under the usual
 543    arithmetic conversions.  The default conversions have already been
 544    applied, and enumerated types converted to their compatible integer
 545    types.  The resulting type is unqualified and has no attributes.
 546
 547    This is the type for the result of most arithmetic operations
 548    if the operands have the given two types.  */
 549
 550 static tree
 551 c_common_type (tree t1, tree t2)
 552 {
 553   enum tree_code code1;
 554   enum tree_code code2;
 555
 556   /* If one type is nonsense, use the other.  */
 557   if (t1 == error_mark_node)
 558     return t2;
 559   if (t2 == error_mark_node)
 560     return t1;
 561
 562   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 563     t1 = TYPE_MAIN_VARIANT (t1);
 564
 565   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 566     t2 = TYPE_MAIN_VARIANT (t2);
 567
 568   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 569     t1 = build_type_attribute_variant (t1, NULL_TREE);
 570
 571   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 572     t2 = build_type_attribute_variant (t2, NULL_TREE);
 573
 574   /* Save time if the two types are the same.  */
 575
 576   if (t1 == t2) return t1;
 577
 578   code1 = TREE_CODE (t1);
 579   code2 = TREE_CODE (t2);
 580
 581   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 582               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 583   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 584               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 585
 586   /* If one type is a vector type, return that type.  (How the usual
 587      arithmetic conversions apply to the vector types extension is not
 588      precisely specified.)  */
 589   if (code1 == VECTOR_TYPE)
 590     return t1;
 591
 592   if (code2 == VECTOR_TYPE)
 593     return t2;
 594
 595   /* If one type is complex, form the common type of the non-complex
 596      components, then make that complex.  Use T1 or T2 if it is the
 597      required type.  */
 598   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 599     {
 600       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 601       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 602       tree subtype = c_common_type (subtype1, subtype2);
 603
 604       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 605         return t1;
 606       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 607         return t2;
 608       else
 609         return build_complex_type (subtype);
 610     }
 611
 612   /* If only one is real, use it as the result.  */
 613
 614   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 615     return t1;
 616
 617   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 618     return t2;
 619
 620   /* If both are real and either are decimal floating point types, use
 621      the decimal floating point type with the greater precision. */
 622
 623   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 624     {
 625       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 626           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 627         return dfloat128_type_node;
 628       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 629                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 630         return dfloat64_type_node;
 631       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 632                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 633         return dfloat32_type_node;
 634     }
 635
 636   /* Both real or both integers; use the one with greater precision.  */
 637
 638   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 639     return t1;
 640   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 641     return t2;
 642
 643   /* Same precision.  Prefer long longs to longs to ints when the
 644      same precision, following the C99 rules on integer type rank
 645      (which are equivalent to the C90 rules for C90 types).  */
 646
 647   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 648       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 649     return long_long_unsigned_type_node;
 650
 651   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 652       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 653     {
 654       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 655         return long_long_unsigned_type_node;
 656       else
 657         return long_long_integer_type_node;
 658     }
 659
 660   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 661       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 662     return long_unsigned_type_node;
 663
 664   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 665       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 666     {
 667       /* But preserve unsignedness from the other type,
 668          since long cannot hold all the values of an unsigned int.  */
 669       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 670         return long_unsigned_type_node;
 671       else
 672         return long_integer_type_node;
 673     }
 674
 675   /* Likewise, prefer long double to double even if same size.  */
 676   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 677       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 678     return long_double_type_node;
 679
 680   /* Otherwise prefer the unsigned one.  */
 681
 682   if (TYPE_UNSIGNED (t1))
 683     return t1;
 684   else
 685     return t2;
 686 }
 687 \f
 688 /* Wrapper around c_common_type that is used by c-common.c and other
 689    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 690    are allowed here and are converted to their compatible integer types.
 691    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 692    preferably a non-Boolean type as the common type.  */
 693 tree
 694 common_type (tree t1, tree t2)
 695 {
 696   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 697     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 698   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 699     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 700
 701   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 702   if (TREE_CODE (t1) == BOOLEAN_TYPE
 703       && TREE_CODE (t2) == BOOLEAN_TYPE)
 704     return boolean_type_node;
 705
 706   /* If either type is BOOLEAN_TYPE, then return the other.  */
 707   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 708     return t2;
 709   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 710     return t1;
 711
 712   return c_common_type (t1, t2);
 713 }
 714
 715 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 716    or various other operations.  Return 2 if they are compatible
 717    but a warning may be needed if you use them together.  */
 718
 719 int
 720 comptypes (tree type1, tree type2)
 721 {
 722   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 723   int val;
 724
 725   val = comptypes_internal (type1, type2);
 726   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 727
 728   return val;
 729 }\f
 730 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 731    or various other operations.  Return 2 if they are compatible
 732    but a warning may be needed if you use them together.  This
 733    differs from comptypes, in that we don't free the seen types.  */
 734
 735 static int
 736 comptypes_internal (tree type1, tree type2)
 737 {
 738   tree t1 = type1;
 739   tree t2 = type2;
 740   int attrval, val;
 741
 742   /* Suppress errors caused by previously reported errors.  */
 743
 744   if (t1 == t2 || !t1 || !t2
 745       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 746     return 1;
 747
 748   /* If either type is the internal version of sizetype, return the
 749      language version.  */
 750   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 751       && TYPE_ORIG_SIZE_TYPE (t1))
 752     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 753
 754   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 755       && TYPE_ORIG_SIZE_TYPE (t2))
 756     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 757
 758
 759   /* Enumerated types are compatible with integer types, but this is
 760      not transitive: two enumerated types in the same translation unit
 761      are compatible with each other only if they are the same type.  */
 762
 763   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 764     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 765   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 766     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 767
 768   if (t1 == t2)
 769     return 1;
 770
 771   /* Different classes of types can't be compatible.  */
 772
 773   if (TREE_CODE (t1) != TREE_CODE (t2))
 774     return 0;
 775
 776   /* Qualifiers must match. C99 6.7.3p9 */
 777
 778   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 779     return 0;
 780
 781   /* Allow for two different type nodes which have essentially the same
 782      definition.  Note that we already checked for equality of the type
 783      qualifiers (just above).  */
 784
 785   if (TREE_CODE (t1) != ARRAY_TYPE
 786       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 787     return 1;
 788
 789   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 790   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 791      return 0;
 792
 793   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 794   val = 0;
 795
 796   switch (TREE_CODE (t1))
 797     {
 798     case POINTER_TYPE:
 799       /* Do not remove mode or aliasing information.  */
 800       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 801           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 802         break;
 803       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 804              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 805       break;
 806
 807     case FUNCTION_TYPE:
 808       val = function_types_compatible_p (t1, t2);
 809       break;
 810
 811     case ARRAY_TYPE:
 812       {
 813         tree d1 = TYPE_DOMAIN (t1);
 814         tree d2 = TYPE_DOMAIN (t2);
 815         bool d1_variable, d2_variable;
 816         bool d1_zero, d2_zero;
 817         val = 1;
 818
 819         /* Target types must match incl. qualifiers.  */
 820         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 821             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 822           return 0;
 823
 824         /* Sizes must match unless one is missing or variable.  */
 825         if (d1 == 0 || d2 == 0 || d1 == d2)
 826           break;
 827
 828         d1_zero = !TYPE_MAX_VALUE (d1);
 829         d2_zero = !TYPE_MAX_VALUE (d2);
 830
 831         d1_variable = (!d1_zero
 832                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 833                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 834         d2_variable = (!d2_zero
 835                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 836                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 837
 838         if (d1_variable || d2_variable)
 839           break;
 840         if (d1_zero && d2_zero)
 841           break;
 842         if (d1_zero || d2_zero
 843             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 844             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 845           val = 0;
 846
 847         break;
 848       }
 849
 850     case ENUMERAL_TYPE:
 851     case RECORD_TYPE:
 852     case UNION_TYPE:
 853       if (val != 1 && !same_translation_unit_p (t1, t2))
 854         {
 855           if (attrval != 2)
 856             return tagged_types_tu_compatible_p (t1, t2);
 857           val = tagged_types_tu_compatible_p (t1, t2);
 858         }
 859       break;
 860
 861     case VECTOR_TYPE:
 862       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 863             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
 864       break;
 865
 866     default:
 867       break;
 868     }
 869   return attrval == 2 && val == 1 ? 2 : val;
 870 }
 871
 872 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 873    ignoring their qualifiers.  */
 874
 875 static int
 876 comp_target_types (tree ttl, tree ttr)
 877 {
 878   int val;
 879   tree mvl, mvr;
 880
 881   /* Do not lose qualifiers on element types of array types that are
 882      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 883   mvl = TREE_TYPE (ttl);
 884   mvr = TREE_TYPE (ttr);
 885   if (TREE_CODE (mvl) != ARRAY_TYPE)
 886     mvl = TYPE_MAIN_VARIANT (mvl);
 887   if (TREE_CODE (mvr) != ARRAY_TYPE)
 888     mvr = TYPE_MAIN_VARIANT (mvr);
 889   val = comptypes (mvl, mvr);
 890
 891   if (val == 2 && pedantic)
 892     pedwarn ("types are not quite compatible");
 893   return val;
 894 }
 895 \f
 896 /* Subroutines of `comptypes'.  */
 897
 898 /* Determine whether two trees derive from the same translation unit.
 899    If the CONTEXT chain ends in a null, that tree's context is still
 900    being parsed, so if two trees have context chains ending in null,
 901    they're in the same translation unit.  */
 902 int
 903 same_translation_unit_p (tree t1, tree t2)
 904 {
 905   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 906     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 907       {
 908       case tcc_declaration:
 909         t1 = DECL_CONTEXT (t1); break;
 910       case tcc_type:
 911         t1 = TYPE_CONTEXT (t1); break;
 912       case tcc_exceptional:
 913         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 914       default: gcc_unreachable ();
 915       }
 916
 917   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 918     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 919       {
 920       case tcc_declaration:
 921         t2 = DECL_CONTEXT (t2); break;
 922       case tcc_type:
 923         t2 = TYPE_CONTEXT (t2); break;
 924       case tcc_exceptional:
 925         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 926       default: gcc_unreachable ();
 927       }
 928
 929   return t1 == t2;
 930 }
 931
 932 /* Allocate the seen two types, assuming that they are compatible. */
 933
 934 static struct tagged_tu_seen_cache *
 935 alloc_tagged_tu_seen_cache (tree t1, tree t2)
 936 {
 937   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
 938   tu->next = tagged_tu_seen_base;
 939   tu->t1 = t1;
 940   tu->t2 = t2;
 941
 942   tagged_tu_seen_base = tu;
 943
 944   /* The C standard says that two structures in different translation
 945      units are compatible with each other only if the types of their
 946      fields are compatible (among other things).  We assume that they
 947      are compatible until proven otherwise when building the cache.
 948      An example where this can occur is:
 949      struct a
 950      {
 951        struct a *next;
 952      };
 953      If we are comparing this against a similar struct in another TU,
 954      and did not assume they were compatible, we end up with an infinite
 955      loop.  */
 956   tu->val = 1;
 957   return tu;
 958 }
 959
 960 /* Free the seen types until we get to TU_TIL. */
 961
 962 static void
 963 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
 964 {
 965   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
 966   while (tu != tu_til)
 967     {
 968       struct tagged_tu_seen_cache *tu1 = (struct tagged_tu_seen_cache*)tu;
 969       tu = tu1->next;
 970       free (tu1);
 971     }
 972   tagged_tu_seen_base = tu_til;
 973 }
 974
 975 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 976    compatible.  If the two types are not the same (which has been
 977    checked earlier), this can only happen when multiple translation
 978    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 979    rules.  */
 980
 981 static int
 982 tagged_types_tu_compatible_p (tree t1, tree t2)
 983 {
 984   tree s1, s2;
 985   bool needs_warning = false;
 986
 987   /* We have to verify that the tags of the types are the same.  This
 988      is harder than it looks because this may be a typedef, so we have
 989      to go look at the original type.  It may even be a typedef of a
 990      typedef...
 991      In the case of compiler-created builtin structs the TYPE_DECL
 992      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 993   while (TYPE_NAME (t1)
 994          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 995          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 996     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 997
 998   while (TYPE_NAME (t2)
 999          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1000          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1001     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1002
1003   /* C90 didn't have the requirement that the two tags be the same.  */
1004   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1005     return 0;
1006
1007   /* C90 didn't say what happened if one or both of the types were
1008      incomplete; we choose to follow C99 rules here, which is that they
1009      are compatible.  */
1010   if (TYPE_SIZE (t1) == NULL
1011       || TYPE_SIZE (t2) == NULL)
1012     return 1;
1013
1014   {
1015     const struct tagged_tu_seen_cache * tts_i;
1016     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1017       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1018         return tts_i->val;
1019   }
1020
1021   switch (TREE_CODE (t1))
1022     {
1023     case ENUMERAL_TYPE:
1024       {
1025         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1026         /* Speed up the case where the type values are in the same order.  */
1027         tree tv1 = TYPE_VALUES (t1);
1028         tree tv2 = TYPE_VALUES (t2);
1029
1030         if (tv1 == tv2)
1031           {
1032             return 1;
1033           }
1034
1035         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1036           {
1037             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1038               break;
1039             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1040               {
1041                 tu->val = 0;
1042                 return 0;
1043               }
1044           }
1045
1046         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1047           {
1048             return 1;
1049           }
1050         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1051           {
1052             tu->val = 0;
1053             return 0;
1054           }
1055
1056         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1057           {
1058             tu->val = 0;
1059             return 0;
1060           }
1061
1062         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1063           {
1064             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1065             if (s2 == NULL
1066                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1067               {
1068                 tu->val = 0;
1069                 return 0;
1070               }
1071           }
1072         return 1;
1073       }
1074
1075     case UNION_TYPE:
1076       {
1077         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1078         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1079           {
1080             tu->val = 0;
1081             return 0;
1082           }
1083
1084         /*  Speed up the common case where the fields are in the same order. */
1085         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1086              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1087           {
1088             int result;
1089
1090
1091             if (DECL_NAME (s1) == NULL
1092                 || DECL_NAME (s1) != DECL_NAME (s2))
1093               break;
1094             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1095             if (result == 0)
1096               {
1097                 tu->val = 0;
1098                 return 0;
1099               }
1100             if (result == 2)
1101               needs_warning = true;
1102
1103             if (TREE_CODE (s1) == FIELD_DECL
1104                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1105                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1106               {
1107                 tu->val = 0;
1108                 return 0;
1109               }
1110           }
1111         if (!s1 && !s2)
1112           {
1113             tu->val = needs_warning ? 2 : 1;
1114             return tu->val;
1115           }
1116
1117         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1118           {
1119             bool ok = false;
1120
1121             if (DECL_NAME (s1) != NULL)
1122               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1123                 if (DECL_NAME (s1) == DECL_NAME (s2))
1124                   {
1125                     int result;
1126                     result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1127                     if (result == 0)
1128                       {
1129                         tu->val = 0;
1130                         return 0;
1131                       }
1132                     if (result == 2)
1133                       needs_warning = true;
1134
1135                     if (TREE_CODE (s1) == FIELD_DECL
1136                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1137                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
1138                       break;
1139
1140                     ok = true;
1141                     break;
1142                   }
1143             if (!ok)
1144               {
1145                 tu->val = 0;
1146                 return 0;
1147               }
1148           }
1149         tu->val = needs_warning ? 2 : 10;
1150         return tu->val;
1151       }
1152
1153     case RECORD_TYPE:
1154       {
1155         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1156
1157         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1158              s1 && s2;
1159              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1160           {
1161             int result;
1162             if (TREE_CODE (s1) != TREE_CODE (s2)
1163                 || DECL_NAME (s1) != DECL_NAME (s2))
1164               break;
1165             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1166             if (result == 0)
1167               break;
1168             if (result == 2)
1169               needs_warning = true;
1170
1171             if (TREE_CODE (s1) == FIELD_DECL
1172                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1173                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1174               break;
1175           }
1176         if (s1 && s2)
1177           tu->val = 0;
1178         else
1179           tu->val = needs_warning ? 2 : 1;
1180         return tu->val;
1181       }
1182
1183     default:
1184       gcc_unreachable ();
1185     }
1186 }
1187
1188 /* Return 1 if two function types F1 and F2 are compatible.
1189    If either type specifies no argument types,
1190    the other must specify a fixed number of self-promoting arg types.
1191    Otherwise, if one type specifies only the number of arguments,
1192    the other must specify that number of self-promoting arg types.
1193    Otherwise, the argument types must match.  */
1194
1195 static int
1196 function_types_compatible_p (tree f1, tree f2)
1197 {
1198   tree args1, args2;
1199   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1200   int val = 1;
1201   int val1;
1202   tree ret1, ret2;
1203
1204   ret1 = TREE_TYPE (f1);
1205   ret2 = TREE_TYPE (f2);
1206
1207   /* 'volatile' qualifiers on a function's return type used to mean
1208      the function is noreturn.  */
1209   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1210     pedwarn ("function return types not compatible due to %<volatile%>");
1211   if (TYPE_VOLATILE (ret1))
1212     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1213                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1214   if (TYPE_VOLATILE (ret2))
1215     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1216                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1217   val = comptypes_internal (ret1, ret2);
1218   if (val == 0)
1219     return 0;
1220
1221   args1 = TYPE_ARG_TYPES (f1);
1222   args2 = TYPE_ARG_TYPES (f2);
1223
1224   /* An unspecified parmlist matches any specified parmlist
1225      whose argument types don't need default promotions.  */
1226
1227   if (args1 == 0)
1228     {
1229       if (!self_promoting_args_p (args2))
1230         return 0;
1231       /* If one of these types comes from a non-prototype fn definition,
1232          compare that with the other type's arglist.
1233          If they don't match, ask for a warning (but no error).  */
1234       if (TYPE_ACTUAL_ARG_TYPES (f1)
1235           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1236         val = 2;
1237       return val;
1238     }
1239   if (args2 == 0)
1240     {
1241       if (!self_promoting_args_p (args1))
1242         return 0;
1243       if (TYPE_ACTUAL_ARG_TYPES (f2)
1244           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1245         val = 2;
1246       return val;
1247     }
1248
1249   /* Both types have argument lists: compare them and propagate results.  */
1250   val1 = type_lists_compatible_p (args1, args2);
1251   return val1 != 1 ? val1 : val;
1252 }
1253
1254 /* Check two lists of types for compatibility,
1255    returning 0 for incompatible, 1 for compatible,
1256    or 2 for compatible with warning.  */
1257
1258 static int
1259 type_lists_compatible_p (tree args1, tree args2)
1260 {
1261   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1262   int val = 1;
1263   int newval = 0;
1264
1265   while (1)
1266     {
1267       tree a1, mv1, a2, mv2;
1268       if (args1 == 0 && args2 == 0)
1269         return val;
1270       /* If one list is shorter than the other,
1271          they fail to match.  */
1272       if (args1 == 0 || args2 == 0)
1273         return 0;
1274       mv1 = a1 = TREE_VALUE (args1);
1275       mv2 = a2 = TREE_VALUE (args2);
1276       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1277         mv1 = TYPE_MAIN_VARIANT (mv1);
1278       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1279         mv2 = TYPE_MAIN_VARIANT (mv2);
1280       /* A null pointer instead of a type
1281          means there is supposed to be an argument
1282          but nothing is specified about what type it has.
1283          So match anything that self-promotes.  */
1284       if (a1 == 0)
1285         {
1286           if (c_type_promotes_to (a2) != a2)
1287             return 0;
1288         }
1289       else if (a2 == 0)
1290         {
1291           if (c_type_promotes_to (a1) != a1)
1292             return 0;
1293         }
1294       /* If one of the lists has an error marker, ignore this arg.  */
1295       else if (TREE_CODE (a1) == ERROR_MARK
1296                || TREE_CODE (a2) == ERROR_MARK)
1297         ;
1298       else if (!(newval = comptypes_internal (mv1, mv2)))
1299         {
1300           /* Allow  wait (union {union wait *u; int *i} *)
1301              and  wait (union wait *)  to be compatible.  */
1302           if (TREE_CODE (a1) == UNION_TYPE
1303               && (TYPE_NAME (a1) == 0
1304                   || TYPE_TRANSPARENT_UNION (a1))
1305               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1306               && tree_int_cst_equal (TYPE_SIZE (a1),
1307                                      TYPE_SIZE (a2)))
1308             {
1309               tree memb;
1310               for (memb = TYPE_FIELDS (a1);
1311                    memb; memb = TREE_CHAIN (memb))
1312                 {
1313                   tree mv3 = TREE_TYPE (memb);
1314                   if (mv3 && mv3 != error_mark_node
1315                       && TREE_CODE (mv3) != ARRAY_TYPE)
1316                     mv3 = TYPE_MAIN_VARIANT (mv3);
1317                   if (comptypes_internal (mv3, mv2))
1318                     break;
1319                 }
1320               if (memb == 0)
1321                 return 0;
1322             }
1323           else if (TREE_CODE (a2) == UNION_TYPE
1324                    && (TYPE_NAME (a2) == 0
1325                        || TYPE_TRANSPARENT_UNION (a2))
1326                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1327                    && tree_int_cst_equal (TYPE_SIZE (a2),
1328                                           TYPE_SIZE (a1)))
1329             {
1330               tree memb;
1331               for (memb = TYPE_FIELDS (a2);
1332                    memb; memb = TREE_CHAIN (memb))
1333                 {
1334                   tree mv3 = TREE_TYPE (memb);
1335                   if (mv3 && mv3 != error_mark_node
1336                       && TREE_CODE (mv3) != ARRAY_TYPE)
1337                     mv3 = TYPE_MAIN_VARIANT (mv3);
1338                   if (comptypes_internal (mv3, mv1))
1339                     break;
1340                 }
1341               if (memb == 0)
1342                 return 0;
1343             }
1344           else
1345             return 0;
1346         }
1347
1348       /* comptypes said ok, but record if it said to warn.  */
1349       if (newval > val)
1350         val = newval;
1351
1352       args1 = TREE_CHAIN (args1);
1353       args2 = TREE_CHAIN (args2);
1354     }
1355 }
1356 \f
1357 /* Compute the size to increment a pointer by.  */
1358
1359 static tree
1360 c_size_in_bytes (tree type)
1361 {
1362   enum tree_code code = TREE_CODE (type);
1363
1364   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1365     return size_one_node;
1366
1367   if (!COMPLETE_OR_VOID_TYPE_P (type))
1368     {
1369       error ("arithmetic on pointer to an incomplete type");
1370       return size_one_node;
1371     }
1372
1373   /* Convert in case a char is more than one unit.  */
1374   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1375                      size_int (TYPE_PRECISION (char_type_node)
1376                                / BITS_PER_UNIT));
1377 }
1378 \f
1379 /* Return either DECL or its known constant value (if it has one).  */
1380
1381 tree
1382 decl_constant_value (tree decl)
1383 {
1384   if (/* Don't change a variable array bound or initial value to a constant
1385          in a place where a variable is invalid.  Note that DECL_INITIAL
1386          isn't valid for a PARM_DECL.  */
1387       current_function_decl != 0
1388       && TREE_CODE (decl) != PARM_DECL
1389       && !TREE_THIS_VOLATILE (decl)
1390       && TREE_READONLY (decl)
1391       && DECL_INITIAL (decl) != 0
1392       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1393       /* This is invalid if initial value is not constant.
1394          If it has either a function call, a memory reference,
1395          or a variable, then re-evaluating it could give different results.  */
1396       && TREE_CONSTANT (DECL_INITIAL (decl))
1397       /* Check for cases where this is sub-optimal, even though valid.  */
1398       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1399     return DECL_INITIAL (decl);
1400   return decl;
1401 }
1402
1403 /* Return either DECL or its known constant value (if it has one), but
1404    return DECL if pedantic or DECL has mode BLKmode.  This is for
1405    bug-compatibility with the old behavior of decl_constant_value
1406    (before GCC 3.0); every use of this function is a bug and it should
1407    be removed before GCC 3.1.  It is not appropriate to use pedantic
1408    in a way that affects optimization, and BLKmode is probably not the
1409    right test for avoiding misoptimizations either.  */
1410
1411 static tree
1412 decl_constant_value_for_broken_optimization (tree decl)
1413 {
1414   tree ret;
1415
1416   if (pedantic || DECL_MODE (decl) == BLKmode)
1417     return decl;
1418
1419   ret = decl_constant_value (decl);
1420   /* Avoid unwanted tree sharing between the initializer and current
1421      function's body where the tree can be modified e.g. by the
1422      gimplifier.  */
1423   if (ret != decl && TREE_STATIC (decl))
1424     ret = unshare_expr (ret);
1425   return ret;
1426 }
1427
1428 /* Convert the array expression EXP to a pointer.  */
1429 static tree
1430 array_to_pointer_conversion (tree exp)
1431 {
1432   tree orig_exp = exp;
1433   tree type = TREE_TYPE (exp);
1434   tree adr;
1435   tree restype = TREE_TYPE (type);
1436   tree ptrtype;
1437
1438   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1439
1440   STRIP_TYPE_NOPS (exp);
1441
1442   if (TREE_NO_WARNING (orig_exp))
1443     TREE_NO_WARNING (exp) = 1;
1444
1445   ptrtype = build_pointer_type (restype);
1446
1447   if (TREE_CODE (exp) == INDIRECT_REF)
1448     return convert (ptrtype, TREE_OPERAND (exp, 0));
1449
1450   if (TREE_CODE (exp) == VAR_DECL)
1451     {
1452       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1453          ADDR_EXPR because it's the best way of representing what
1454          happens in C when we take the address of an array and place
1455          it in a pointer to the element type.  */
1456       adr = build1 (ADDR_EXPR, ptrtype, exp);
1457       if (!c_mark_addressable (exp))
1458         return error_mark_node;
1459       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1460       return adr;
1461     }
1462
1463   /* This way is better for a COMPONENT_REF since it can
1464      simplify the offset for a component.  */
1465   adr = build_unary_op (ADDR_EXPR, exp, 1);
1466   return convert (ptrtype, adr);
1467 }
1468
1469 /* Convert the function expression EXP to a pointer.  */
1470 static tree
1471 function_to_pointer_conversion (tree exp)
1472 {
1473   tree orig_exp = exp;
1474
1475   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1476
1477   STRIP_TYPE_NOPS (exp);
1478
1479   if (TREE_NO_WARNING (orig_exp))
1480     TREE_NO_WARNING (exp) = 1;
1481
1482   return build_unary_op (ADDR_EXPR, exp, 0);
1483 }
1484
1485 /* Perform the default conversion of arrays and functions to pointers.
1486    Return the result of converting EXP.  For any other expression, just
1487    return EXP after removing NOPs.  */
1488
1489 struct c_expr
1490 default_function_array_conversion (struct c_expr exp)
1491 {
1492   tree orig_exp = exp.value;
1493   tree type = TREE_TYPE (exp.value);
1494   enum tree_code code = TREE_CODE (type);
1495
1496   switch (code)
1497     {
1498     case ARRAY_TYPE:
1499       {
1500         bool not_lvalue = false;
1501         bool lvalue_array_p;
1502
1503         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1504                 || TREE_CODE (exp.value) == NOP_EXPR
1505                 || TREE_CODE (exp.value) == CONVERT_EXPR)
1506                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1507           {
1508             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1509               not_lvalue = true;
1510             exp.value = TREE_OPERAND (exp.value, 0);
1511           }
1512
1513         if (TREE_NO_WARNING (orig_exp))
1514           TREE_NO_WARNING (exp.value) = 1;
1515
1516         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1517         if (!flag_isoc99 && !lvalue_array_p)
1518           {
1519             /* Before C99, non-lvalue arrays do not decay to pointers.
1520                Normally, using such an array would be invalid; but it can
1521                be used correctly inside sizeof or as a statement expression.
1522                Thus, do not give an error here; an error will result later.  */
1523             return exp;
1524           }
1525
1526         exp.value = array_to_pointer_conversion (exp.value);
1527       }
1528       break;
1529     case FUNCTION_TYPE:
1530       exp.value = function_to_pointer_conversion (exp.value);
1531       break;
1532     default:
1533       STRIP_TYPE_NOPS (exp.value);
1534       if (TREE_NO_WARNING (orig_exp))
1535         TREE_NO_WARNING (exp.value) = 1;
1536       break;
1537     }
1538
1539   return exp;
1540 }
1541
1542
1543 /* EXP is an expression of integer type.  Apply the integer promotions
1544    to it and return the promoted value.  */
1545
1546 tree
1547 perform_integral_promotions (tree exp)
1548 {
1549   tree type = TREE_TYPE (exp);
1550   enum tree_code code = TREE_CODE (type);
1551
1552   gcc_assert (INTEGRAL_TYPE_P (type));
1553
1554   /* Normally convert enums to int,
1555      but convert wide enums to something wider.  */
1556   if (code == ENUMERAL_TYPE)
1557     {
1558       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1559                                           TYPE_PRECISION (integer_type_node)),
1560                                      ((TYPE_PRECISION (type)
1561                                        >= TYPE_PRECISION (integer_type_node))
1562                                       && TYPE_UNSIGNED (type)));
1563
1564       return convert (type, exp);
1565     }
1566
1567   /* ??? This should no longer be needed now bit-fields have their
1568      proper types.  */
1569   if (TREE_CODE (exp) == COMPONENT_REF
1570       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1571       /* If it's thinner than an int, promote it like a
1572          c_promoting_integer_type_p, otherwise leave it alone.  */
1573       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1574                                TYPE_PRECISION (integer_type_node)))
1575     return convert (integer_type_node, exp);
1576
1577   if (c_promoting_integer_type_p (type))
1578     {
1579       /* Preserve unsignedness if not really getting any wider.  */
1580       if (TYPE_UNSIGNED (type)
1581           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1582         return convert (unsigned_type_node, exp);
1583
1584       return convert (integer_type_node, exp);
1585     }
1586
1587   return exp;
1588 }
1589
1590
1591 /* Perform default promotions for C data used in expressions.
1592    Enumeral types or short or char are converted to int.
1593    In addition, manifest constants symbols are replaced by their values.  */
1594
1595 tree
1596 default_conversion (tree exp)
1597 {
1598   tree orig_exp;
1599   tree type = TREE_TYPE (exp);
1600   enum tree_code code = TREE_CODE (type);
1601
1602   /* Functions and arrays have been converted during parsing.  */
1603   gcc_assert (code != FUNCTION_TYPE);
1604   if (code == ARRAY_TYPE)
1605     return exp;
1606
1607   /* Constants can be used directly unless they're not loadable.  */
1608   if (TREE_CODE (exp) == CONST_DECL)
1609     exp = DECL_INITIAL (exp);
1610
1611   /* Replace a nonvolatile const static variable with its value unless
1612      it is an array, in which case we must be sure that taking the
1613      address of the array produces consistent results.  */
1614   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1615     {
1616       exp = decl_constant_value_for_broken_optimization (exp);
1617       type = TREE_TYPE (exp);
1618     }
1619
1620   /* Strip no-op conversions.  */
1621   orig_exp = exp;
1622   STRIP_TYPE_NOPS (exp);
1623
1624   if (TREE_NO_WARNING (orig_exp))
1625     TREE_NO_WARNING (exp) = 1;
1626
1627   if (INTEGRAL_TYPE_P (type))
1628     return perform_integral_promotions (exp);
1629
1630   if (code == VOID_TYPE)
1631     {
1632       error ("void value not ignored as it ought to be");
1633       return error_mark_node;
1634     }
1635   return exp;
1636 }
1637 \f
1638 /* Look up COMPONENT in a structure or union DECL.
1639
1640    If the component name is not found, returns NULL_TREE.  Otherwise,
1641    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1642    stepping down the chain to the component, which is in the last
1643    TREE_VALUE of the list.  Normally the list is of length one, but if
1644    the component is embedded within (nested) anonymous structures or
1645    unions, the list steps down the chain to the component.  */
1646
1647 static tree
1648 lookup_field (tree decl, tree component)
1649 {
1650   tree type = TREE_TYPE (decl);
1651   tree field;
1652
1653   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1654      to the field elements.  Use a binary search on this array to quickly
1655      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1656      will always be set for structures which have many elements.  */
1657
1658   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1659     {
1660       int bot, top, half;
1661       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1662
1663       field = TYPE_FIELDS (type);
1664       bot = 0;
1665       top = TYPE_LANG_SPECIFIC (type)->s->len;
1666       while (top - bot > 1)
1667         {
1668           half = (top - bot + 1) >> 1;
1669           field = field_array[bot+half];
1670
1671           if (DECL_NAME (field) == NULL_TREE)
1672             {
1673               /* Step through all anon unions in linear fashion.  */
1674               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1675                 {
1676                   field = field_array[bot++];
1677                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1678                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1679                     {
1680                       tree anon = lookup_field (field, component);
1681
1682                       if (anon)
1683                         return tree_cons (NULL_TREE, field, anon);
1684                     }
1685                 }
1686
1687               /* Entire record is only anon unions.  */
1688               if (bot > top)
1689                 return NULL_TREE;
1690
1691               /* Restart the binary search, with new lower bound.  */
1692               continue;
1693             }
1694
1695           if (DECL_NAME (field) == component)
1696             break;
1697           if (DECL_NAME (field) < component)
1698             bot += half;
1699           else
1700             top = bot + half;
1701         }
1702
1703       if (DECL_NAME (field_array[bot]) == component)
1704         field = field_array[bot];
1705       else if (DECL_NAME (field) != component)
1706         return NULL_TREE;
1707     }
1708   else
1709     {
1710       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1711         {
1712           if (DECL_NAME (field) == NULL_TREE
1713               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1714                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1715             {
1716               tree anon = lookup_field (field, component);
1717
1718               if (anon)
1719                 return tree_cons (NULL_TREE, field, anon);
1720             }
1721
1722           if (DECL_NAME (field) == component)
1723             break;
1724         }
1725
1726       if (field == NULL_TREE)
1727         return NULL_TREE;
1728     }
1729
1730   return tree_cons (NULL_TREE, field, NULL_TREE);
1731 }
1732
1733 /* Make an expression to refer to the COMPONENT field of
1734    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1735
1736 tree
1737 build_component_ref (tree datum, tree component)
1738 {
1739   tree type = TREE_TYPE (datum);
1740   enum tree_code code = TREE_CODE (type);
1741   tree field = NULL;
1742   tree ref;
1743
1744   if (!objc_is_public (datum, component))
1745     return error_mark_node;
1746
1747   /* See if there is a field or component with name COMPONENT.  */
1748
1749   if (code == RECORD_TYPE || code == UNION_TYPE)
1750     {
1751       if (!COMPLETE_TYPE_P (type))
1752         {
1753           c_incomplete_type_error (NULL_TREE, type);
1754           return error_mark_node;
1755         }
1756
1757       field = lookup_field (datum, component);
1758
1759       if (!field)
1760         {
1761           error ("%qT has no member named %qE", type, component);
1762           return error_mark_node;
1763         }
1764
1765       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1766          This might be better solved in future the way the C++ front
1767          end does it - by giving the anonymous entities each a
1768          separate name and type, and then have build_component_ref
1769          recursively call itself.  We can't do that here.  */
1770       do
1771         {
1772           tree subdatum = TREE_VALUE (field);
1773
1774           if (TREE_TYPE (subdatum) == error_mark_node)
1775             return error_mark_node;
1776
1777           ref = build3 (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1778                         NULL_TREE);
1779           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1780             TREE_READONLY (ref) = 1;
1781           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1782             TREE_THIS_VOLATILE (ref) = 1;
1783
1784           if (TREE_DEPRECATED (subdatum))
1785             warn_deprecated_use (subdatum);
1786
1787           datum = ref;
1788
1789           field = TREE_CHAIN (field);
1790         }
1791       while (field);
1792
1793       return ref;
1794     }
1795   else if (code != ERROR_MARK)
1796     error ("request for member %qE in something not a structure or union",
1797            component);
1798
1799   return error_mark_node;
1800 }
1801 \f
1802 /* Given an expression PTR for a pointer, return an expression
1803    for the value pointed to.
1804    ERRORSTRING is the name of the operator to appear in error messages.  */
1805
1806 tree
1807 build_indirect_ref (tree ptr, const char *errorstring)
1808 {
1809   tree pointer = default_conversion (ptr);
1810   tree type = TREE_TYPE (pointer);
1811
1812   if (TREE_CODE (type) == POINTER_TYPE)
1813     {
1814       if (TREE_CODE (pointer) == ADDR_EXPR
1815           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1816               == TREE_TYPE (type)))
1817         return TREE_OPERAND (pointer, 0);
1818       else
1819         {
1820           tree t = TREE_TYPE (type);
1821           tree ref;
1822
1823           ref = build1 (INDIRECT_REF, t, pointer);
1824
1825           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1826             {
1827               error ("dereferencing pointer to incomplete type");
1828               return error_mark_node;
1829             }
1830           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1831             warning (0, "dereferencing %<void *%> pointer");
1832
1833           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1834              so that we get the proper error message if the result is used
1835              to assign to.  Also, &* is supposed to be a no-op.
1836              And ANSI C seems to specify that the type of the result
1837              should be the const type.  */
1838           /* A de-reference of a pointer to const is not a const.  It is valid
1839              to change it via some other pointer.  */
1840           TREE_READONLY (ref) = TYPE_READONLY (t);
1841           TREE_SIDE_EFFECTS (ref)
1842             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1843           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1844           return ref;
1845         }
1846     }
1847   else if (TREE_CODE (pointer) != ERROR_MARK)
1848     error ("invalid type argument of %qs", errorstring);
1849   return error_mark_node;
1850 }
1851
1852 /* This handles expressions of the form "a[i]", which denotes
1853    an array reference.
1854
1855    This is logically equivalent in C to *(a+i), but we may do it differently.
1856    If A is a variable or a member, we generate a primitive ARRAY_REF.
1857    This avoids forcing the array out of registers, and can work on
1858    arrays that are not lvalues (for example, members of structures returned
1859    by functions).  */
1860
1861 tree
1862 build_array_ref (tree array, tree index)
1863 {
1864   bool swapped = false;
1865   if (TREE_TYPE (array) == error_mark_node
1866       || TREE_TYPE (index) == error_mark_node)
1867     return error_mark_node;
1868
1869   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1870       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1871     {
1872       tree temp;
1873       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1874           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1875         {
1876           error ("subscripted value is neither array nor pointer");
1877           return error_mark_node;
1878         }
1879       temp = array;
1880       array = index;
1881       index = temp;
1882       swapped = true;
1883     }
1884
1885   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1886     {
1887       error ("array subscript is not an integer");
1888       return error_mark_node;
1889     }
1890
1891   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1892     {
1893       error ("subscripted value is pointer to function");
1894       return error_mark_node;
1895     }
1896
1897   /* ??? Existing practice has been to warn only when the char
1898      index is syntactically the index, not for char[array].  */
1899   if (!swapped)
1900      warn_array_subscript_with_type_char (index);
1901
1902   /* Apply default promotions *after* noticing character types.  */
1903   index = default_conversion (index);
1904
1905   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1906
1907   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1908     {
1909       tree rval, type;
1910
1911       /* An array that is indexed by a non-constant
1912          cannot be stored in a register; we must be able to do
1913          address arithmetic on its address.
1914          Likewise an array of elements of variable size.  */
1915       if (TREE_CODE (index) != INTEGER_CST
1916           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1917               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1918         {
1919           if (!c_mark_addressable (array))
1920             return error_mark_node;
1921         }
1922       /* An array that is indexed by a constant value which is not within
1923          the array bounds cannot be stored in a register either; because we
1924          would get a crash in store_bit_field/extract_bit_field when trying
1925          to access a non-existent part of the register.  */
1926       if (TREE_CODE (index) == INTEGER_CST
1927           && TYPE_DOMAIN (TREE_TYPE (array))
1928           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1929         {
1930           if (!c_mark_addressable (array))
1931             return error_mark_node;
1932         }
1933
1934       if (pedantic)
1935         {
1936           tree foo = array;
1937           while (TREE_CODE (foo) == COMPONENT_REF)
1938             foo = TREE_OPERAND (foo, 0);
1939           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1940             pedwarn ("ISO C forbids subscripting %<register%> array");
1941           else if (!flag_isoc99 && !lvalue_p (foo))
1942             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1943         }
1944
1945       type = TREE_TYPE (TREE_TYPE (array));
1946       if (TREE_CODE (type) != ARRAY_TYPE)
1947         type = TYPE_MAIN_VARIANT (type);
1948       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1949       /* Array ref is const/volatile if the array elements are
1950          or if the array is.  */
1951       TREE_READONLY (rval)
1952         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1953             | TREE_READONLY (array));
1954       TREE_SIDE_EFFECTS (rval)
1955         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1956             | TREE_SIDE_EFFECTS (array));
1957       TREE_THIS_VOLATILE (rval)
1958         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1959             /* This was added by rms on 16 Nov 91.
1960                It fixes  vol struct foo *a;  a->elts[1]
1961                in an inline function.
1962                Hope it doesn't break something else.  */
1963             | TREE_THIS_VOLATILE (array));
1964       return require_complete_type (fold (rval));
1965     }
1966   else
1967     {
1968       tree ar = default_conversion (array);
1969
1970       if (ar == error_mark_node)
1971         return ar;
1972
1973       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1974       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1975
1976       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1977                                  "array indexing");
1978     }
1979 }
1980 \f
1981 /* Build an external reference to identifier ID.  FUN indicates
1982    whether this will be used for a function call.  LOC is the source
1983    location of the identifier.  */
1984 tree
1985 build_external_ref (tree id, int fun, location_t loc)
1986 {
1987   tree ref;
1988   tree decl = lookup_name (id);
1989
1990   /* In Objective-C, an instance variable (ivar) may be preferred to
1991      whatever lookup_name() found.  */
1992   decl = objc_lookup_ivar (decl, id);
1993
1994   if (decl && decl != error_mark_node)
1995     ref = decl;
1996   else if (fun)
1997     /* Implicit function declaration.  */
1998     ref = implicitly_declare (id);
1999   else if (decl == error_mark_node)
2000     /* Don't complain about something that's already been
2001        complained about.  */
2002     return error_mark_node;
2003   else
2004     {
2005       undeclared_variable (id, loc);
2006       return error_mark_node;
2007     }
2008
2009   if (TREE_TYPE (ref) == error_mark_node)
2010     return error_mark_node;
2011
2012   if (TREE_DEPRECATED (ref))
2013     warn_deprecated_use (ref);
2014
2015   if (!skip_evaluation)
2016     assemble_external (ref);
2017   TREE_USED (ref) = 1;
2018
2019   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2020     {
2021       if (!in_sizeof && !in_typeof)
2022         C_DECL_USED (ref) = 1;
2023       else if (DECL_INITIAL (ref) == 0
2024                && DECL_EXTERNAL (ref)
2025                && !TREE_PUBLIC (ref))
2026         record_maybe_used_decl (ref);
2027     }
2028
2029   if (TREE_CODE (ref) == CONST_DECL)
2030     {
2031       ref = DECL_INITIAL (ref);
2032       TREE_CONSTANT (ref) = 1;
2033       TREE_INVARIANT (ref) = 1;
2034     }
2035   else if (current_function_decl != 0
2036            && !DECL_FILE_SCOPE_P (current_function_decl)
2037            && (TREE_CODE (ref) == VAR_DECL
2038                || TREE_CODE (ref) == PARM_DECL
2039                || TREE_CODE (ref) == FUNCTION_DECL))
2040     {
2041       tree context = decl_function_context (ref);
2042
2043       if (context != 0 && context != current_function_decl)
2044         DECL_NONLOCAL (ref) = 1;
2045     }
2046
2047   return ref;
2048 }
2049
2050 /* Record details of decls possibly used inside sizeof or typeof.  */
2051 struct maybe_used_decl
2052 {
2053   /* The decl.  */
2054   tree decl;
2055   /* The level seen at (in_sizeof + in_typeof).  */
2056   int level;
2057   /* The next one at this level or above, or NULL.  */
2058   struct maybe_used_decl *next;
2059 };
2060
2061 static struct maybe_used_decl *maybe_used_decls;
2062
2063 /* Record that DECL, an undefined static function reference seen
2064    inside sizeof or typeof, might be used if the operand of sizeof is
2065    a VLA type or the operand of typeof is a variably modified
2066    type.  */
2067
2068 static void
2069 record_maybe_used_decl (tree decl)
2070 {
2071   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2072   t->decl = decl;
2073   t->level = in_sizeof + in_typeof;
2074   t->next = maybe_used_decls;
2075   maybe_used_decls = t;
2076 }
2077
2078 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2079    USED is false, just discard them.  If it is true, mark them used
2080    (if no longer inside sizeof or typeof) or move them to the next
2081    level up (if still inside sizeof or typeof).  */
2082
2083 void
2084 pop_maybe_used (bool used)
2085 {
2086   struct maybe_used_decl *p = maybe_used_decls;
2087   int cur_level = in_sizeof + in_typeof;
2088   while (p && p->level > cur_level)
2089     {
2090       if (used)
2091         {
2092           if (cur_level == 0)
2093             C_DECL_USED (p->decl) = 1;
2094           else
2095             p->level = cur_level;
2096         }
2097       p = p->next;
2098     }
2099   if (!used || cur_level == 0)
2100     maybe_used_decls = p;
2101 }
2102
2103 /* Return the result of sizeof applied to EXPR.  */
2104
2105 struct c_expr
2106 c_expr_sizeof_expr (struct c_expr expr)
2107 {
2108   struct c_expr ret;
2109   if (expr.value == error_mark_node)
2110     {
2111       ret.value = error_mark_node;
2112       ret.original_code = ERROR_MARK;
2113       pop_maybe_used (false);
2114     }
2115   else
2116     {
2117       ret.value = c_sizeof (TREE_TYPE (expr.value));
2118       ret.original_code = ERROR_MARK;
2119       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2120     }
2121   return ret;
2122 }
2123
2124 /* Return the result of sizeof applied to T, a structure for the type
2125    name passed to sizeof (rather than the type itself).  */
2126
2127 struct c_expr
2128 c_expr_sizeof_type (struct c_type_name *t)
2129 {
2130   tree type;
2131   struct c_expr ret;
2132   type = groktypename (t);
2133   ret.value = c_sizeof (type);
2134   ret.original_code = ERROR_MARK;
2135   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
2136   return ret;
2137 }
2138
2139 /* Build a function call to function FUNCTION with parameters PARAMS.
2140    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2141    TREE_VALUE of each node is a parameter-expression.
2142    FUNCTION's data type may be a function type or a pointer-to-function.  */
2143
2144 tree
2145 build_function_call (tree function, tree params)
2146 {
2147   tree fntype, fundecl = 0;
2148   tree coerced_params;
2149   tree name = NULL_TREE, result;
2150   tree tem;
2151
2152   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2153   STRIP_TYPE_NOPS (function);
2154
2155   /* Convert anything with function type to a pointer-to-function.  */
2156   if (TREE_CODE (function) == FUNCTION_DECL)
2157     {
2158       /* Implement type-directed function overloading for builtins.
2159          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2160          handle all the type checking.  The result is a complete expression
2161          that implements this function call.  */
2162       tem = resolve_overloaded_builtin (function, params);
2163       if (tem)
2164         return tem;
2165
2166       name = DECL_NAME (function);
2167       fundecl = function;
2168     }
2169   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2170     function = function_to_pointer_conversion (function);
2171
2172   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2173      expressions, like those used for ObjC messenger dispatches.  */
2174   function = objc_rewrite_function_call (function, params);
2175
2176   fntype = TREE_TYPE (function);
2177
2178   if (TREE_CODE (fntype) == ERROR_MARK)
2179     return error_mark_node;
2180
2181   if (!(TREE_CODE (fntype) == POINTER_TYPE
2182         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2183     {
2184       error ("called object %qE is not a function", function);
2185       return error_mark_node;
2186     }
2187
2188   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2189     current_function_returns_abnormally = 1;
2190
2191   /* fntype now gets the type of function pointed to.  */
2192   fntype = TREE_TYPE (fntype);
2193
2194   /* Check that the function is called through a compatible prototype.
2195      If it is not, replace the call by a trap, wrapped up in a compound
2196      expression if necessary.  This has the nice side-effect to prevent
2197      the tree-inliner from generating invalid assignment trees which may
2198      blow up in the RTL expander later.  */
2199   if ((TREE_CODE (function) == NOP_EXPR
2200        || TREE_CODE (function) == CONVERT_EXPR)
2201       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2202       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2203       && !comptypes (fntype, TREE_TYPE (tem)))
2204     {
2205       tree return_type = TREE_TYPE (fntype);
2206       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2207                                        NULL_TREE);
2208
2209       /* This situation leads to run-time undefined behavior.  We can't,
2210          therefore, simply error unless we can prove that all possible
2211          executions of the program must execute the code.  */
2212       warning (0, "function called through a non-compatible type");
2213
2214       /* We can, however, treat "undefined" any way we please.
2215          Call abort to encourage the user to fix the program.  */
2216       inform ("if this code is reached, the program will abort");
2217
2218       if (VOID_TYPE_P (return_type))
2219         return trap;
2220       else
2221         {
2222           tree rhs;
2223
2224           if (AGGREGATE_TYPE_P (return_type))
2225             rhs = build_compound_literal (return_type,
2226                                           build_constructor (return_type, 0));
2227           else
2228             rhs = fold_convert (return_type, integer_zero_node);
2229
2230           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2231         }
2232     }
2233
2234   /* Convert the parameters to the types declared in the
2235      function prototype, or apply default promotions.  */
2236
2237   coerced_params
2238     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2239
2240   if (coerced_params == error_mark_node)
2241     return error_mark_node;
2242
2243   /* Check that the arguments to the function are valid.  */
2244
2245   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2246                             TYPE_ARG_TYPES (fntype));
2247
2248   if (require_constant_value)
2249     {
2250       result = fold_build3_initializer (CALL_EXPR, TREE_TYPE (fntype),
2251                                         function, coerced_params, NULL_TREE);
2252
2253       if (TREE_CONSTANT (result)
2254           && (name == NULL_TREE
2255               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2256         pedwarn_init ("initializer element is not constant");
2257     }
2258   else
2259     result = fold_build3 (CALL_EXPR, TREE_TYPE (fntype),
2260                           function, coerced_params, NULL_TREE);
2261
2262   if (VOID_TYPE_P (TREE_TYPE (result)))
2263     return result;
2264   return require_complete_type (result);
2265 }
2266 \f
2267 /* Convert the argument expressions in the list VALUES
2268    to the types in the list TYPELIST.  The result is a list of converted
2269    argument expressions, unless there are too few arguments in which
2270    case it is error_mark_node.
2271
2272    If TYPELIST is exhausted, or when an element has NULL as its type,
2273    perform the default conversions.
2274
2275    PARMLIST is the chain of parm decls for the function being called.
2276    It may be 0, if that info is not available.
2277    It is used only for generating error messages.
2278
2279    FUNCTION is a tree for the called function.  It is used only for
2280    error messages, where it is formatted with %qE.
2281
2282    This is also where warnings about wrong number of args are generated.
2283
2284    Both VALUES and the returned value are chains of TREE_LIST nodes
2285    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2286
2287 static tree
2288 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2289 {
2290   tree typetail, valtail;
2291   tree result = NULL;
2292   int parmnum;
2293   tree selector;
2294
2295   /* Change pointer to function to the function itself for
2296      diagnostics.  */
2297   if (TREE_CODE (function) == ADDR_EXPR
2298       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2299     function = TREE_OPERAND (function, 0);
2300
2301   /* Handle an ObjC selector specially for diagnostics.  */
2302   selector = objc_message_selector ();
2303
2304   /* Scan the given expressions and types, producing individual
2305      converted arguments and pushing them on RESULT in reverse order.  */
2306
2307   for (valtail = values, typetail = typelist, parmnum = 0;
2308        valtail;
2309        valtail = TREE_CHAIN (valtail), parmnum++)
2310     {
2311       tree type = typetail ? TREE_VALUE (typetail) : 0;
2312       tree val = TREE_VALUE (valtail);
2313       tree rname = function;
2314       int argnum = parmnum + 1;
2315       const char *invalid_func_diag;
2316
2317       if (type == void_type_node)
2318         {
2319           error ("too many arguments to function %qE", function);
2320           break;
2321         }
2322
2323       if (selector && argnum > 2)
2324         {
2325           rname = selector;
2326           argnum -= 2;
2327         }
2328
2329       STRIP_TYPE_NOPS (val);
2330
2331       val = require_complete_type (val);
2332
2333       if (type != 0)
2334         {
2335           /* Formal parm type is specified by a function prototype.  */
2336           tree parmval;
2337
2338           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2339             {
2340               error ("type of formal parameter %d is incomplete", parmnum + 1);
2341               parmval = val;
2342             }
2343           else
2344             {
2345               /* Optionally warn about conversions that
2346                  differ from the default conversions.  */
2347               if (warn_conversion || warn_traditional)
2348                 {
2349                   unsigned int formal_prec = TYPE_PRECISION (type);
2350
2351                   if (INTEGRAL_TYPE_P (type)
2352                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2353                     warning (0, "passing argument %d of %qE as integer "
2354                              "rather than floating due to prototype",
2355                              argnum, rname);
2356                   if (INTEGRAL_TYPE_P (type)
2357                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2358                     warning (0, "passing argument %d of %qE as integer "
2359                              "rather than complex due to prototype",
2360                              argnum, rname);
2361                   else if (TREE_CODE (type) == COMPLEX_TYPE
2362                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2363                     warning (0, "passing argument %d of %qE as complex "
2364                              "rather than floating due to prototype",
2365                              argnum, rname);
2366                   else if (TREE_CODE (type) == REAL_TYPE
2367                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2368                     warning (0, "passing argument %d of %qE as floating "
2369                              "rather than integer due to prototype",
2370                              argnum, rname);
2371                   else if (TREE_CODE (type) == COMPLEX_TYPE
2372                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2373                     warning (0, "passing argument %d of %qE as complex "
2374                              "rather than integer due to prototype",
2375                              argnum, rname);
2376                   else if (TREE_CODE (type) == REAL_TYPE
2377                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2378                     warning (0, "passing argument %d of %qE as floating "
2379                              "rather than complex due to prototype",
2380                              argnum, rname);
2381                   /* ??? At some point, messages should be written about
2382                      conversions between complex types, but that's too messy
2383                      to do now.  */
2384                   else if (TREE_CODE (type) == REAL_TYPE
2385                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2386                     {
2387                       /* Warn if any argument is passed as `float',
2388                          since without a prototype it would be `double'.  */
2389                       if (formal_prec == TYPE_PRECISION (float_type_node)
2390                           && type != dfloat32_type_node)
2391                         warning (0, "passing argument %d of %qE as %<float%> "
2392                                  "rather than %<double%> due to prototype",
2393                                  argnum, rname);
2394
2395                       /* Warn if mismatch between argument and prototype
2396                          for decimal float types.  Warn of conversions with
2397                          binary float types and of precision narrowing due to
2398                          prototype. */
2399                       else if (type != TREE_TYPE (val)
2400                                && (type == dfloat32_type_node
2401                                    || type == dfloat64_type_node
2402                                    || type == dfloat128_type_node
2403                                    || TREE_TYPE (val) == dfloat32_type_node
2404                                    || TREE_TYPE (val) == dfloat64_type_node
2405                                    || TREE_TYPE (val) == dfloat128_type_node)
2406                                && (formal_prec
2407                                    <= TYPE_PRECISION (TREE_TYPE (val))
2408                                    || (type == dfloat128_type_node
2409                                        && (TREE_TYPE (val)
2410                                            != dfloat64_type_node
2411                                            && (TREE_TYPE (val)
2412                                                != dfloat32_type_node)))
2413                                    || (type == dfloat64_type_node
2414                                        && (TREE_TYPE (val)
2415                                            != dfloat32_type_node))))
2416                         warning (0, "passing argument %d of %qE as %qT "
2417                                  "rather than %qT due to prototype",
2418                                  argnum, rname, type, TREE_TYPE (val));
2419
2420                     }
2421                   /* Detect integer changing in width or signedness.
2422                      These warnings are only activated with
2423                      -Wconversion, not with -Wtraditional.  */
2424                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2425                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2426                     {
2427                       tree would_have_been = default_conversion (val);
2428                       tree type1 = TREE_TYPE (would_have_been);
2429
2430                       if (TREE_CODE (type) == ENUMERAL_TYPE
2431                           && (TYPE_MAIN_VARIANT (type)
2432                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2433                         /* No warning if function asks for enum
2434                            and the actual arg is that enum type.  */
2435                         ;
2436                       else if (formal_prec != TYPE_PRECISION (type1))
2437                         warning (OPT_Wconversion, "passing argument %d of %qE "
2438                                  "with different width due to prototype",
2439                                  argnum, rname);
2440                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2441                         ;
2442                       /* Don't complain if the formal parameter type
2443                          is an enum, because we can't tell now whether
2444                          the value was an enum--even the same enum.  */
2445                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2446                         ;
2447                       else if (TREE_CODE (val) == INTEGER_CST
2448                                && int_fits_type_p (val, type))
2449                         /* Change in signedness doesn't matter
2450                            if a constant value is unaffected.  */
2451                         ;
2452                       /* If the value is extended from a narrower
2453                          unsigned type, it doesn't matter whether we
2454                          pass it as signed or unsigned; the value
2455                          certainly is the same either way.  */
2456                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2457                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2458                         ;
2459                       else if (TYPE_UNSIGNED (type))
2460                         warning (OPT_Wconversion, "passing argument %d of %qE "
2461                                  "as unsigned due to prototype",
2462                                  argnum, rname);
2463                       else
2464                         warning (OPT_Wconversion, "passing argument %d of %qE "
2465                                  "as signed due to prototype", argnum, rname);
2466                     }
2467                 }
2468
2469               parmval = convert_for_assignment (type, val, ic_argpass,
2470                                                 fundecl, function,
2471                                                 parmnum + 1);
2472
2473               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2474                   && INTEGRAL_TYPE_P (type)
2475                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2476                 parmval = default_conversion (parmval);
2477             }
2478           result = tree_cons (NULL_TREE, parmval, result);
2479         }
2480       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2481                && (TYPE_PRECISION (TREE_TYPE (val))
2482                    < TYPE_PRECISION (double_type_node))
2483                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2484         /* Convert `float' to `double'.  */
2485         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2486       else if ((invalid_func_diag =
2487                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2488         {
2489           error (invalid_func_diag);
2490           return error_mark_node;
2491         }
2492       else
2493         /* Convert `short' and `char' to full-size `int'.  */
2494         result = tree_cons (NULL_TREE, default_conversion (val), result);
2495
2496       if (typetail)
2497         typetail = TREE_CHAIN (typetail);
2498     }
2499
2500   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2501     {
2502       error ("too few arguments to function %qE", function);
2503       return error_mark_node;
2504     }
2505
2506   return nreverse (result);
2507 }
2508 \f
2509 /* This is the entry point used by the parser to build unary operators
2510    in the input.  CODE, a tree_code, specifies the unary operator, and
2511    ARG is the operand.  For unary plus, the C parser currently uses
2512    CONVERT_EXPR for code.  */
2513
2514 struct c_expr
2515 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2516 {
2517   struct c_expr result;
2518
2519   result.original_code = ERROR_MARK;
2520   result.value = build_unary_op (code, arg.value, 0);
2521   overflow_warning (result.value);
2522   return result;
2523 }
2524
2525 /* This is the entry point used by the parser to build binary operators
2526    in the input.  CODE, a tree_code, specifies the binary operator, and
2527    ARG1 and ARG2 are the operands.  In addition to constructing the
2528    expression, we check for operands that were written with other binary
2529    operators in a way that is likely to confuse the user.  */
2530
2531 struct c_expr
2532 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2533                         struct c_expr arg2)
2534 {
2535   struct c_expr result;
2536
2537   enum tree_code code1 = arg1.original_code;
2538   enum tree_code code2 = arg2.original_code;
2539
2540   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2541   result.original_code = code;
2542
2543   if (TREE_CODE (result.value) == ERROR_MARK)
2544     return result;
2545
2546   /* Check for cases such as x+y<<z which users are likely
2547      to misinterpret.  */
2548   if (warn_parentheses)
2549     {
2550       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2551         {
2552           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2553               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2554             warning (OPT_Wparentheses,
2555                      "suggest parentheses around + or - inside shift");
2556         }
2557
2558       if (code == TRUTH_ORIF_EXPR)
2559         {
2560           if (code1 == TRUTH_ANDIF_EXPR
2561               || code2 == TRUTH_ANDIF_EXPR)
2562             warning (OPT_Wparentheses,
2563                      "suggest parentheses around && within ||");
2564         }
2565
2566       if (code == BIT_IOR_EXPR)
2567         {
2568           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2569               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2570               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2571               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2572             warning (OPT_Wparentheses,
2573                      "suggest parentheses around arithmetic in operand of |");
2574           /* Check cases like x|y==z */
2575           if (TREE_CODE_CLASS (code1) == tcc_comparison
2576               || TREE_CODE_CLASS (code2) == tcc_comparison)
2577             warning (OPT_Wparentheses,
2578                      "suggest parentheses around comparison in operand of |");
2579         }
2580
2581       if (code == BIT_XOR_EXPR)
2582         {
2583           if (code1 == BIT_AND_EXPR
2584               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2585               || code2 == BIT_AND_EXPR
2586               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2587             warning (OPT_Wparentheses,
2588                      "suggest parentheses around arithmetic in operand of ^");
2589           /* Check cases like x^y==z */
2590           if (TREE_CODE_CLASS (code1) == tcc_comparison
2591               || TREE_CODE_CLASS (code2) == tcc_comparison)
2592             warning (OPT_Wparentheses,
2593                      "suggest parentheses around comparison in operand of ^");
2594         }
2595
2596       if (code == BIT_AND_EXPR)
2597         {
2598           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2599               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2600             warning (OPT_Wparentheses,
2601                      "suggest parentheses around + or - in operand of &");
2602           /* Check cases like x&y==z */
2603           if (TREE_CODE_CLASS (code1) == tcc_comparison
2604               || TREE_CODE_CLASS (code2) == tcc_comparison)
2605             warning (OPT_Wparentheses,
2606                      "suggest parentheses around comparison in operand of &");
2607         }
2608       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2609       if (TREE_CODE_CLASS (code) == tcc_comparison
2610           && (TREE_CODE_CLASS (code1) == tcc_comparison
2611               || TREE_CODE_CLASS (code2) == tcc_comparison))
2612         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
2613                  "have their mathematical meaning");
2614
2615     }
2616
2617   /* Warn about comparisons against string literals, with the exception
2618      of testing for equality or inequality of a string literal with NULL.  */
2619   if (code == EQ_EXPR || code == NE_EXPR)
2620     {
2621       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2622           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2623         warning (OPT_Wstring_literal_comparison,
2624                  "comparison with string literal");
2625     }
2626   else if (TREE_CODE_CLASS (code) == tcc_comparison
2627            && (code1 == STRING_CST || code2 == STRING_CST))
2628     warning (OPT_Wstring_literal_comparison,
2629              "comparison with string literal");
2630
2631   overflow_warning (result.value);
2632
2633   return result;
2634 }
2635 \f
2636 /* Return a tree for the difference of pointers OP0 and OP1.
2637    The resulting tree has type int.  */
2638
2639 static tree
2640 pointer_diff (tree op0, tree op1)
2641 {
2642   tree restype = ptrdiff_type_node;
2643
2644   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2645   tree con0, con1, lit0, lit1;
2646   tree orig_op1 = op1;
2647
2648   if (pedantic || warn_pointer_arith)
2649     {
2650       if (TREE_CODE (target_type) == VOID_TYPE)
2651         pedwarn ("pointer of type %<void *%> used in subtraction");
2652       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2653         pedwarn ("pointer to a function used in subtraction");
2654     }
2655
2656   /* If the conversion to ptrdiff_type does anything like widening or
2657      converting a partial to an integral mode, we get a convert_expression
2658      that is in the way to do any simplifications.
2659      (fold-const.c doesn't know that the extra bits won't be needed.
2660      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2661      different mode in place.)
2662      So first try to find a common term here 'by hand'; we want to cover
2663      at least the cases that occur in legal static initializers.  */
2664   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2665       && (TYPE_PRECISION (TREE_TYPE (op0))
2666           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2667     con0 = TREE_OPERAND (op0, 0);
2668   else
2669     con0 = op0;
2670   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2671       && (TYPE_PRECISION (TREE_TYPE (op1))
2672           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2673     con1 = TREE_OPERAND (op1, 0);
2674   else
2675     con1 = op1;
2676
2677   if (TREE_CODE (con0) == PLUS_EXPR)
2678     {
2679       lit0 = TREE_OPERAND (con0, 1);
2680       con0 = TREE_OPERAND (con0, 0);
2681     }
2682   else
2683     lit0 = integer_zero_node;
2684
2685   if (TREE_CODE (con1) == PLUS_EXPR)
2686     {
2687       lit1 = TREE_OPERAND (con1, 1);
2688       con1 = TREE_OPERAND (con1, 0);
2689     }
2690   else
2691     lit1 = integer_zero_node;
2692
2693   if (operand_equal_p (con0, con1, 0))
2694     {
2695       op0 = lit0;
2696       op1 = lit1;
2697     }
2698
2699
2700   /* First do the subtraction as integers;
2701      then drop through to build the divide operator.
2702      Do not do default conversions on the minus operator
2703      in case restype is a short type.  */
2704
2705   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2706                          convert (restype, op1), 0);
2707   /* This generates an error if op1 is pointer to incomplete type.  */
2708   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2709     error ("arithmetic on pointer to an incomplete type");
2710
2711   /* This generates an error if op0 is pointer to incomplete type.  */
2712   op1 = c_size_in_bytes (target_type);
2713
2714   /* Divide by the size, in easiest possible way.  */
2715   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2716 }
2717 \f
2718 /* Construct and perhaps optimize a tree representation
2719    for a unary operation.  CODE, a tree_code, specifies the operation
2720    and XARG is the operand.
2721    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2722    the default promotions (such as from short to int).
2723    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2724    allows non-lvalues; this is only used to handle conversion of non-lvalue
2725    arrays to pointers in C99.  */
2726
2727 tree
2728 build_unary_op (enum tree_code code, tree xarg, int flag)
2729 {
2730   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2731   tree arg = xarg;
2732   tree argtype = 0;
2733   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2734   tree val;
2735   int noconvert = flag;
2736   const char *invalid_op_diag;
2737
2738   if (typecode == ERROR_MARK)
2739     return error_mark_node;
2740   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2741     typecode = INTEGER_TYPE;
2742
2743   if ((invalid_op_diag
2744        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2745     {
2746       error (invalid_op_diag);
2747       return error_mark_node;
2748     }
2749
2750   switch (code)
2751     {
2752     case CONVERT_EXPR:
2753       /* This is used for unary plus, because a CONVERT_EXPR
2754          is enough to prevent anybody from looking inside for
2755          associativity, but won't generate any code.  */
2756       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2757             || typecode == COMPLEX_TYPE
2758             || typecode == VECTOR_TYPE))
2759         {
2760           error ("wrong type argument to unary plus");
2761           return error_mark_node;
2762         }
2763       else if (!noconvert)
2764         arg = default_conversion (arg);
2765       arg = non_lvalue (arg);
2766       break;
2767
2768     case NEGATE_EXPR:
2769       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2770             || typecode == COMPLEX_TYPE
2771             || typecode == VECTOR_TYPE))
2772         {
2773           error ("wrong type argument to unary minus");
2774           return error_mark_node;
2775         }
2776       else if (!noconvert)
2777         arg = default_conversion (arg);
2778       break;
2779
2780     case BIT_NOT_EXPR:
2781       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2782         {
2783           if (!noconvert)
2784             arg = default_conversion (arg);
2785         }
2786       else if (typecode == COMPLEX_TYPE)
2787         {
2788           code = CONJ_EXPR;
2789           if (pedantic)
2790             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2791           if (!noconvert)
2792             arg = default_conversion (arg);
2793         }
2794       else
2795         {
2796           error ("wrong type argument to bit-complement");
2797           return error_mark_node;
2798         }
2799       break;
2800
2801     case ABS_EXPR:
2802       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2803         {
2804           error ("wrong type argument to abs");
2805           return error_mark_node;
2806         }
2807       else if (!noconvert)
2808         arg = default_conversion (arg);
2809       break;
2810
2811     case CONJ_EXPR:
2812       /* Conjugating a real value is a no-op, but allow it anyway.  */
2813       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2814             || typecode == COMPLEX_TYPE))
2815         {
2816           error ("wrong type argument to conjugation");
2817           return error_mark_node;
2818         }
2819       else if (!noconvert)
2820         arg = default_conversion (arg);
2821       break;
2822
2823     case TRUTH_NOT_EXPR:
2824       if (typecode != INTEGER_TYPE
2825           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2826           && typecode != COMPLEX_TYPE)
2827         {
2828           error ("wrong type argument to unary exclamation mark");
2829           return error_mark_node;
2830         }
2831       arg = c_objc_common_truthvalue_conversion (arg);
2832       return invert_truthvalue (arg);
2833
2834     case REALPART_EXPR:
2835       if (TREE_CODE (arg) == COMPLEX_CST)
2836         return TREE_REALPART (arg);
2837       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2838         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2839       else
2840         return arg;
2841
2842     case IMAGPART_EXPR:
2843       if (TREE_CODE (arg) == COMPLEX_CST)
2844         return TREE_IMAGPART (arg);
2845       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2846         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2847       else
2848         return convert (TREE_TYPE (arg), integer_zero_node);
2849
2850     case PREINCREMENT_EXPR:
2851     case POSTINCREMENT_EXPR:
2852     case PREDECREMENT_EXPR:
2853     case POSTDECREMENT_EXPR:
2854
2855       /* Increment or decrement the real part of the value,
2856          and don't change the imaginary part.  */
2857       if (typecode == COMPLEX_TYPE)
2858         {
2859           tree real, imag;
2860
2861           if (pedantic)
2862             pedwarn ("ISO C does not support %<++%> and %<--%>"
2863                      " on complex types");
2864
2865           arg = stabilize_reference (arg);
2866           real = build_unary_op (REALPART_EXPR, arg, 1);
2867           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2868           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2869                          build_unary_op (code, real, 1), imag);
2870         }
2871
2872       /* Report invalid types.  */
2873
2874       if (typecode != POINTER_TYPE
2875           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2876         {
2877           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2878             error ("wrong type argument to increment");
2879           else
2880             error ("wrong type argument to decrement");
2881
2882           return error_mark_node;
2883         }
2884
2885       {
2886         tree inc;
2887         tree result_type = TREE_TYPE (arg);
2888
2889         arg = get_unwidened (arg, 0);
2890         argtype = TREE_TYPE (arg);
2891
2892         /* Compute the increment.  */
2893
2894         if (typecode == POINTER_TYPE)
2895           {
2896             /* If pointer target is an undefined struct,
2897                we just cannot know how to do the arithmetic.  */
2898             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2899               {
2900                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2901                   error ("increment of pointer to unknown structure");
2902                 else
2903                   error ("decrement of pointer to unknown structure");
2904               }
2905             else if ((pedantic || warn_pointer_arith)
2906                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2907                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2908               {
2909                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2910                   pedwarn ("wrong type argument to increment");
2911                 else
2912                   pedwarn ("wrong type argument to decrement");
2913               }
2914
2915             inc = c_size_in_bytes (TREE_TYPE (result_type));
2916           }
2917         else
2918           inc = integer_one_node;
2919
2920         inc = convert (argtype, inc);
2921
2922         /* Complain about anything else that is not a true lvalue.  */
2923         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2924                                     || code == POSTINCREMENT_EXPR)
2925                                    ? lv_increment
2926                                    : lv_decrement)))
2927           return error_mark_node;
2928
2929         /* Report a read-only lvalue.  */
2930         if (TREE_READONLY (arg))
2931           {
2932             readonly_error (arg,
2933                             ((code == PREINCREMENT_EXPR
2934                               || code == POSTINCREMENT_EXPR)
2935                              ? lv_increment : lv_decrement));
2936             return error_mark_node;
2937           }
2938
2939         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2940           val = boolean_increment (code, arg);
2941         else
2942           val = build2 (code, TREE_TYPE (arg), arg, inc);
2943         TREE_SIDE_EFFECTS (val) = 1;
2944         val = convert (result_type, val);
2945         if (TREE_CODE (val) != code)
2946           TREE_NO_WARNING (val) = 1;
2947         return val;
2948       }
2949
2950     case ADDR_EXPR:
2951       /* Note that this operation never does default_conversion.  */
2952
2953       /* Let &* cancel out to simplify resulting code.  */
2954       if (TREE_CODE (arg) == INDIRECT_REF)
2955         {
2956           /* Don't let this be an lvalue.  */
2957           if (lvalue_p (TREE_OPERAND (arg, 0)))
2958             return non_lvalue (TREE_OPERAND (arg, 0));
2959           return TREE_OPERAND (arg, 0);
2960         }
2961
2962       /* For &x[y], return x+y */
2963       if (TREE_CODE (arg) == ARRAY_REF)
2964         {
2965           tree op0 = TREE_OPERAND (arg, 0);
2966           if (!c_mark_addressable (op0))
2967             return error_mark_node;
2968           return build_binary_op (PLUS_EXPR,
2969                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2970                                    ? array_to_pointer_conversion (op0)
2971                                    : op0),
2972                                   TREE_OPERAND (arg, 1), 1);
2973         }
2974
2975       /* Anything not already handled and not a true memory reference
2976          or a non-lvalue array is an error.  */
2977       else if (typecode != FUNCTION_TYPE && !flag
2978                && !lvalue_or_else (arg, lv_addressof))
2979         return error_mark_node;
2980
2981       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2982       argtype = TREE_TYPE (arg);
2983
2984       /* If the lvalue is const or volatile, merge that into the type
2985          to which the address will point.  Note that you can't get a
2986          restricted pointer by taking the address of something, so we
2987          only have to deal with `const' and `volatile' here.  */
2988       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2989           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2990           argtype = c_build_type_variant (argtype,
2991                                           TREE_READONLY (arg),
2992                                           TREE_THIS_VOLATILE (arg));
2993
2994       if (!c_mark_addressable (arg))
2995         return error_mark_node;
2996
2997       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2998                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2999
3000       argtype = build_pointer_type (argtype);
3001
3002       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3003          when we have proper support for integer constant expressions.  */
3004       val = get_base_address (arg);
3005       if (val && TREE_CODE (val) == INDIRECT_REF
3006           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3007         {
3008           tree op0 = fold_convert (argtype, fold_offsetof (arg)), op1;
3009
3010           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3011           return fold_build2 (PLUS_EXPR, argtype, op0, op1);
3012         }
3013
3014       val = build1 (ADDR_EXPR, argtype, arg);
3015
3016       return val;
3017
3018     default:
3019       gcc_unreachable ();
3020     }
3021
3022   if (argtype == 0)
3023     argtype = TREE_TYPE (arg);
3024   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3025                                 : fold_build1 (code, argtype, arg);
3026 }
3027
3028 /* Return nonzero if REF is an lvalue valid for this language.
3029    Lvalues can be assigned, unless their type has TYPE_READONLY.
3030    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3031
3032 static int
3033 lvalue_p (tree ref)
3034 {
3035   enum tree_code code = TREE_CODE (ref);
3036
3037   switch (code)
3038     {
3039     case REALPART_EXPR:
3040     case IMAGPART_EXPR:
3041     case COMPONENT_REF:
3042       return lvalue_p (TREE_OPERAND (ref, 0));
3043
3044     case COMPOUND_LITERAL_EXPR:
3045     case STRING_CST:
3046       return 1;
3047
3048     case INDIRECT_REF:
3049     case ARRAY_REF:
3050     case VAR_DECL:
3051     case PARM_DECL:
3052     case RESULT_DECL:
3053     case ERROR_MARK:
3054       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3055               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3056
3057     case BIND_EXPR:
3058       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3059
3060     default:
3061       return 0;
3062     }
3063 }
3064 \f
3065 /* Give an error for storing in something that is 'const'.  */
3066
3067 static void
3068 readonly_error (tree arg, enum lvalue_use use)
3069 {
3070   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3071               || use == lv_asm);
3072   /* Using this macro rather than (for example) arrays of messages
3073      ensures that all the format strings are checked at compile
3074      time.  */
3075 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3076                                    : (use == lv_increment ? (I)         \
3077                                    : (use == lv_decrement ? (D) : (AS))))
3078   if (TREE_CODE (arg) == COMPONENT_REF)
3079     {
3080       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3081         readonly_error (TREE_OPERAND (arg, 0), use);
3082       else
3083         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3084                              G_("increment of read-only member %qD"),
3085                              G_("decrement of read-only member %qD"),
3086                              G_("read-only member %qD used as %<asm%> output")),
3087                TREE_OPERAND (arg, 1));
3088     }
3089   else if (TREE_CODE (arg) == VAR_DECL)
3090     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3091                          G_("increment of read-only variable %qD"),
3092                          G_("decrement of read-only variable %qD"),
3093                          G_("read-only variable %qD used as %<asm%> output")),
3094            arg);
3095   else
3096     error (READONLY_MSG (G_("assignment of read-only location"),
3097                          G_("increment of read-only location"),
3098                          G_("decrement of read-only location"),
3099                          G_("read-only location used as %<asm%> output")));
3100 }
3101
3102
3103 /* Return nonzero if REF is an lvalue valid for this language;
3104    otherwise, print an error message and return zero.  USE says
3105    how the lvalue is being used and so selects the error message.  */
3106
3107 static int
3108 lvalue_or_else (tree ref, enum lvalue_use use)
3109 {
3110   int win = lvalue_p (ref);
3111
3112   if (!win)
3113     lvalue_error (use);
3114
3115   return win;
3116 }
3117 \f
3118 /* Mark EXP saying that we need to be able to take the
3119    address of it; it should not be allocated in a register.
3120    Returns true if successful.  */
3121
3122 bool
3123 c_mark_addressable (tree exp)
3124 {
3125   tree x = exp;
3126
3127   while (1)
3128     switch (TREE_CODE (x))
3129       {
3130       case COMPONENT_REF:
3131         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3132           {
3133             error
3134               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3135             return false;
3136           }
3137
3138         /* ... fall through ...  */
3139
3140       case ADDR_EXPR:
3141       case ARRAY_REF:
3142       case REALPART_EXPR:
3143       case IMAGPART_EXPR:
3144         x = TREE_OPERAND (x, 0);
3145         break;
3146
3147       case COMPOUND_LITERAL_EXPR:
3148       case CONSTRUCTOR:
3149         TREE_ADDRESSABLE (x) = 1;
3150         return true;
3151
3152       case VAR_DECL:
3153       case CONST_DECL:
3154       case PARM_DECL:
3155       case RESULT_DECL:
3156         if (C_DECL_REGISTER (x)
3157             && DECL_NONLOCAL (x))
3158           {
3159             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3160               {
3161                 error
3162                   ("global register variable %qD used in nested function", x);
3163                 return false;
3164               }
3165             pedwarn ("register variable %qD used in nested function", x);
3166           }
3167         else if (C_DECL_REGISTER (x))
3168           {
3169             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3170               error ("address of global register variable %qD requested", x);
3171             else
3172               error ("address of register variable %qD requested", x);
3173             return false;
3174           }
3175
3176         /* drops in */
3177       case FUNCTION_DECL:
3178         TREE_ADDRESSABLE (x) = 1;
3179         /* drops out */
3180       default:
3181         return true;
3182     }
3183 }
3184 \f
3185 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3186
3187 tree
3188 build_conditional_expr (tree ifexp, tree op1, tree op2)
3189 {
3190   tree type1;
3191   tree type2;
3192   enum tree_code code1;
3193   enum tree_code code2;
3194   tree result_type = NULL;
3195   tree orig_op1 = op1, orig_op2 = op2;
3196
3197   /* Promote both alternatives.  */
3198
3199   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3200     op1 = default_conversion (op1);
3201   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3202     op2 = default_conversion (op2);
3203
3204   if (TREE_CODE (ifexp) == ERROR_MARK
3205       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3206       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3207     return error_mark_node;
3208
3209   type1 = TREE_TYPE (op1);
3210   code1 = TREE_CODE (type1);
3211   type2 = TREE_TYPE (op2);
3212   code2 = TREE_CODE (type2);
3213
3214   /* C90 does not permit non-lvalue arrays in conditional expressions.
3215      In C99 they will be pointers by now.  */
3216   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3217     {
3218       error ("non-lvalue array in conditional expression");
3219       return error_mark_node;
3220     }
3221
3222   /* Quickly detect the usual case where op1 and op2 have the same type
3223      after promotion.  */
3224   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3225     {
3226       if (type1 == type2)
3227         result_type = type1;
3228       else
3229         result_type = TYPE_MAIN_VARIANT (type1);
3230     }
3231   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3232             || code1 == COMPLEX_TYPE)
3233            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3234                || code2 == COMPLEX_TYPE))
3235     {
3236       result_type = c_common_type (type1, type2);
3237
3238       /* If -Wsign-compare, warn here if type1 and type2 have
3239          different signedness.  We'll promote the signed to unsigned
3240          and later code won't know it used to be different.
3241          Do this check on the original types, so that explicit casts
3242          will be considered, but default promotions won't.  */
3243       if (warn_sign_compare && !skip_evaluation)
3244         {
3245           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3246           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3247
3248           if (unsigned_op1 ^ unsigned_op2)
3249             {
3250               /* Do not warn if the result type is signed, since the
3251                  signed type will only be chosen if it can represent
3252                  all the values of the unsigned type.  */
3253               if (!TYPE_UNSIGNED (result_type))
3254                 /* OK */;
3255               /* Do not warn if the signed quantity is an unsuffixed
3256                  integer literal (or some static constant expression
3257                  involving such literals) and it is non-negative.  */
3258               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3259                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3260                 /* OK */;
3261               else
3262                 warning (0, "signed and unsigned type in conditional expression");
3263             }
3264         }
3265     }
3266   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3267     {
3268       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3269         pedwarn ("ISO C forbids conditional expr with only one void side");
3270       result_type = void_type_node;
3271     }
3272   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3273     {
3274       if (comp_target_types (type1, type2))
3275         result_type = common_pointer_type (type1, type2);
3276       else if (null_pointer_constant_p (orig_op1))
3277         result_type = qualify_type (type2, type1);
3278       else if (null_pointer_constant_p (orig_op2))
3279         result_type = qualify_type (type1, type2);
3280       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3281         {
3282           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3283             pedwarn ("ISO C forbids conditional expr between "
3284                      "%<void *%> and function pointer");
3285           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3286                                                           TREE_TYPE (type2)));
3287         }
3288       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3289         {
3290           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3291             pedwarn ("ISO C forbids conditional expr between "
3292                      "%<void *%> and function pointer");
3293           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3294                                                           TREE_TYPE (type1)));
3295         }
3296       else
3297         {
3298           pedwarn ("pointer type mismatch in conditional expression");
3299           result_type = build_pointer_type (void_type_node);
3300         }
3301     }
3302   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3303     {
3304       if (!null_pointer_constant_p (orig_op2))
3305         pedwarn ("pointer/integer type mismatch in conditional expression");
3306       else
3307         {
3308           op2 = null_pointer_node;
3309         }
3310       result_type = type1;
3311     }
3312   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3313     {
3314       if (!null_pointer_constant_p (orig_op1))
3315         pedwarn ("pointer/integer type mismatch in conditional expression");
3316       else
3317         {
3318           op1 = null_pointer_node;
3319         }
3320       result_type = type2;
3321     }
3322
3323   if (!result_type)
3324     {
3325       if (flag_cond_mismatch)
3326         result_type = void_type_node;
3327       else
3328         {
3329           error ("type mismatch in conditional expression");
3330           return error_mark_node;
3331         }
3332     }
3333
3334   /* Merge const and volatile flags of the incoming types.  */
3335   result_type
3336     = build_type_variant (result_type,
3337                           TREE_READONLY (op1) || TREE_READONLY (op2),
3338                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3339
3340   if (result_type != TREE_TYPE (op1))
3341     op1 = convert_and_check (result_type, op1);
3342   if (result_type != TREE_TYPE (op2))
3343     op2 = convert_and_check (result_type, op2);
3344
3345   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3346 }
3347 \f
3348 /* Return a compound expression that performs two expressions and
3349    returns the value of the second of them.  */
3350
3351 tree
3352 build_compound_expr (tree expr1, tree expr2)
3353 {
3354   if (!TREE_SIDE_EFFECTS (expr1))
3355     {
3356       /* The left-hand operand of a comma expression is like an expression
3357          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3358          any side-effects, unless it was explicitly cast to (void).  */
3359       if (warn_unused_value)
3360         {
3361           if (VOID_TYPE_P (TREE_TYPE (expr1))
3362               && (TREE_CODE (expr1) == NOP_EXPR
3363                   || TREE_CODE (expr1) == CONVERT_EXPR))
3364             ; /* (void) a, b */
3365           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3366                    && TREE_CODE (expr1) == COMPOUND_EXPR
3367                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3368                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
3369             ; /* (void) a, (void) b, c */
3370           else
3371             warning (0, "left-hand operand of comma expression has no effect");
3372         }
3373     }
3374
3375   /* With -Wunused, we should also warn if the left-hand operand does have
3376      side-effects, but computes a value which is not used.  For example, in
3377      `foo() + bar(), baz()' the result of the `+' operator is not used,
3378      so we should issue a warning.  */
3379   else if (warn_unused_value)
3380     warn_if_unused_value (expr1, input_location);
3381
3382   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3383 }
3384
3385 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3386
3387 tree
3388 build_c_cast (tree type, tree expr)
3389 {
3390   tree value = expr;
3391
3392   if (type == error_mark_node || expr == error_mark_node)
3393     return error_mark_node;
3394
3395   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3396      only in <protocol> qualifications.  But when constructing cast expressions,
3397      the protocols do matter and must be kept around.  */
3398   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3399     return build1 (NOP_EXPR, type, expr);
3400
3401   type = TYPE_MAIN_VARIANT (type);
3402
3403   if (TREE_CODE (type) == ARRAY_TYPE)
3404     {
3405       error ("cast specifies array type");
3406       return error_mark_node;
3407     }
3408
3409   if (TREE_CODE (type) == FUNCTION_TYPE)
3410     {
3411       error ("cast specifies function type");
3412       return error_mark_node;
3413     }
3414
3415   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3416     {
3417       if (pedantic)
3418         {
3419           if (TREE_CODE (type) == RECORD_TYPE
3420               || TREE_CODE (type) == UNION_TYPE)
3421             pedwarn ("ISO C forbids casting nonscalar to the same type");
3422         }
3423     }
3424   else if (TREE_CODE (type) == UNION_TYPE)
3425     {
3426       tree field;
3427
3428       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3429         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3430                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3431           break;
3432
3433       if (field)
3434         {
3435           tree t;
3436
3437           if (pedantic)
3438             pedwarn ("ISO C forbids casts to union type");
3439           t = digest_init (type,
3440                            build_constructor_single (type, field, value),
3441                            true, 0);
3442           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3443           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3444           return t;
3445         }
3446       error ("cast to union type from type not present in union");
3447       return error_mark_node;
3448     }
3449   else
3450     {
3451       tree otype, ovalue;
3452
3453       if (type == void_type_node)
3454         return build1 (CONVERT_EXPR, type, value);
3455
3456       otype = TREE_TYPE (value);
3457
3458       /* Optionally warn about potentially worrisome casts.  */
3459
3460       if (warn_cast_qual
3461           && TREE_CODE (type) == POINTER_TYPE
3462           && TREE_CODE (otype) == POINTER_TYPE)
3463         {
3464           tree in_type = type;
3465           tree in_otype = otype;
3466           int added = 0;
3467           int discarded = 0;
3468
3469           /* Check that the qualifiers on IN_TYPE are a superset of
3470              the qualifiers of IN_OTYPE.  The outermost level of
3471              POINTER_TYPE nodes is uninteresting and we stop as soon
3472              as we hit a non-POINTER_TYPE node on either type.  */
3473           do
3474             {
3475               in_otype = TREE_TYPE (in_otype);
3476               in_type = TREE_TYPE (in_type);
3477
3478               /* GNU C allows cv-qualified function types.  'const'
3479                  means the function is very pure, 'volatile' means it
3480                  can't return.  We need to warn when such qualifiers
3481                  are added, not when they're taken away.  */
3482               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3483                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3484                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3485               else
3486                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3487             }
3488           while (TREE_CODE (in_type) == POINTER_TYPE
3489                  && TREE_CODE (in_otype) == POINTER_TYPE);
3490
3491           if (added)
3492             warning (0, "cast adds new qualifiers to function type");
3493
3494           if (discarded)
3495             /* There are qualifiers present in IN_OTYPE that are not
3496                present in IN_TYPE.  */
3497             warning (0, "cast discards qualifiers from pointer target type");
3498         }
3499
3500       /* Warn about possible alignment problems.  */
3501       if (STRICT_ALIGNMENT
3502           && TREE_CODE (type) == POINTER_TYPE
3503           && TREE_CODE (otype) == POINTER_TYPE
3504           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3505           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3506           /* Don't warn about opaque types, where the actual alignment
3507              restriction is unknown.  */
3508           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3509                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3510                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3511           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3512         warning (OPT_Wcast_align,
3513                  "cast increases required alignment of target type");
3514
3515       if (TREE_CODE (type) == INTEGER_TYPE
3516           && TREE_CODE (otype) == POINTER_TYPE
3517           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3518       /* Unlike conversion of integers to pointers, where the
3519          warning is disabled for converting constants because
3520          of cases such as SIG_*, warn about converting constant
3521          pointers to integers. In some cases it may cause unwanted
3522          sign extension, and a warning is appropriate.  */
3523         warning (OPT_Wpointer_to_int_cast,
3524                  "cast from pointer to integer of different size");
3525
3526       if (TREE_CODE (value) == CALL_EXPR
3527           && TREE_CODE (type) != TREE_CODE (otype))
3528         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3529                  "to non-matching type %qT", otype, type);
3530
3531       if (TREE_CODE (type) == POINTER_TYPE
3532           && TREE_CODE (otype) == INTEGER_TYPE
3533           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3534           /* Don't warn about converting any constant.  */
3535           && !TREE_CONSTANT (value))
3536         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3537                  "of different size");
3538
3539       strict_aliasing_warning (otype, type, expr);
3540
3541       /* If pedantic, warn for conversions between function and object
3542          pointer types, except for converting a null pointer constant
3543          to function pointer type.  */
3544       if (pedantic
3545           && TREE_CODE (type) == POINTER_TYPE
3546           && TREE_CODE (otype) == POINTER_TYPE
3547           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3548           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3549         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3550
3551       if (pedantic
3552           && TREE_CODE (type) == POINTER_TYPE
3553           && TREE_CODE (otype) == POINTER_TYPE
3554           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3555           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3556           && !null_pointer_constant_p (value))
3557         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3558
3559       ovalue = value;
3560       value = convert (type, value);
3561
3562       /* Ignore any integer overflow caused by the cast.  */
3563       if (TREE_CODE (value) == INTEGER_CST)
3564         {
3565           if (CONSTANT_CLASS_P (ovalue)
3566               && (TREE_OVERFLOW (ovalue) || TREE_CONSTANT_OVERFLOW (ovalue)))
3567             {
3568               /* Avoid clobbering a shared constant.  */
3569               value = copy_node (value);
3570               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3571               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3572             }
3573           else if (TREE_OVERFLOW (value) || TREE_CONSTANT_OVERFLOW (value))
3574             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3575             value = build_int_cst_wide (TREE_TYPE (value),
3576                                         TREE_INT_CST_LOW (value),
3577                                         TREE_INT_CST_HIGH (value));
3578         }
3579     }
3580
3581   /* Don't let a cast be an lvalue.  */
3582   if (value == expr)
3583     value = non_lvalue (value);
3584
3585   return value;
3586 }
3587
3588 /* Interpret a cast of expression EXPR to type TYPE.  */
3589 tree
3590 c_cast_expr (struct c_type_name *type_name, tree expr)
3591 {
3592   tree type;
3593   int saved_wsp = warn_strict_prototypes;
3594
3595   /* This avoids warnings about unprototyped casts on
3596      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3597   if (TREE_CODE (expr) == INTEGER_CST)
3598     warn_strict_prototypes = 0;
3599   type = groktypename (type_name);
3600   warn_strict_prototypes = saved_wsp;
3601
3602   return build_c_cast (type, expr);
3603 }
3604
3605 \f
3606 /* Build an assignment expression of lvalue LHS from value RHS.
3607    MODIFYCODE is the code for a binary operator that we use
3608    to combine the old value of LHS with RHS to get the new value.
3609    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3610
3611 tree
3612 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3613 {
3614   tree result;
3615   tree newrhs;
3616   tree lhstype = TREE_TYPE (lhs);
3617   tree olhstype = lhstype;
3618
3619   /* Types that aren't fully specified cannot be used in assignments.  */
3620   lhs = require_complete_type (lhs);
3621
3622   /* Avoid duplicate error messages from operands that had errors.  */
3623   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3624     return error_mark_node;
3625
3626   STRIP_TYPE_NOPS (rhs);
3627
3628   newrhs = rhs;
3629
3630   /* If a binary op has been requested, combine the old LHS value with the RHS
3631      producing the value we should actually store into the LHS.  */
3632
3633   if (modifycode != NOP_EXPR)
3634     {
3635       lhs = stabilize_reference (lhs);
3636       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3637     }
3638
3639   if (!lvalue_or_else (lhs, lv_assign))
3640     return error_mark_node;
3641
3642   /* Give an error for storing in something that is 'const'.  */
3643
3644   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3645       || ((TREE_CODE (lhstype) == RECORD_TYPE
3646            || TREE_CODE (lhstype) == UNION_TYPE)
3647           && C_TYPE_FIELDS_READONLY (lhstype)))
3648     {
3649       readonly_error (lhs, lv_assign);
3650       return error_mark_node;
3651     }
3652
3653   /* If storing into a structure or union member,
3654      it has probably been given type `int'.
3655      Compute the type that would go with
3656      the actual amount of storage the member occupies.  */
3657
3658   if (TREE_CODE (lhs) == COMPONENT_REF
3659       && (TREE_CODE (lhstype) == INTEGER_TYPE
3660           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3661           || TREE_CODE (lhstype) == REAL_TYPE
3662           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3663     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3664
3665   /* If storing in a field that is in actuality a short or narrower than one,
3666      we must store in the field in its actual type.  */
3667
3668   if (lhstype != TREE_TYPE (lhs))
3669     {
3670       lhs = copy_node (lhs);
3671       TREE_TYPE (lhs) = lhstype;
3672     }
3673
3674   /* Convert new value to destination type.  */
3675
3676   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3677                                    NULL_TREE, NULL_TREE, 0);
3678   if (TREE_CODE (newrhs) == ERROR_MARK)
3679     return error_mark_node;
3680
3681   /* Emit ObjC write barrier, if necessary.  */
3682   if (c_dialect_objc () && flag_objc_gc)
3683     {
3684       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3685       if (result)
3686         return result;
3687     }
3688
3689   /* Scan operands.  */
3690
3691   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3692   TREE_SIDE_EFFECTS (result) = 1;
3693
3694   /* If we got the LHS in a different type for storing in,
3695      convert the result back to the nominal type of LHS
3696      so that the value we return always has the same type
3697      as the LHS argument.  */
3698
3699   if (olhstype == TREE_TYPE (result))
3700     return result;
3701   return convert_for_assignment (olhstype, result, ic_assign,
3702                                  NULL_TREE, NULL_TREE, 0);
3703 }
3704 \f
3705 /* Convert value RHS to type TYPE as preparation for an assignment
3706    to an lvalue of type TYPE.
3707    The real work of conversion is done by `convert'.
3708    The purpose of this function is to generate error messages
3709    for assignments that are not allowed in C.
3710    ERRTYPE says whether it is argument passing, assignment,
3711    initialization or return.
3712
3713    FUNCTION is a tree for the function being called.
3714    PARMNUM is the number of the argument, for printing in error messages.  */
3715
3716 static tree
3717 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3718                         tree fundecl, tree function, int parmnum)
3719 {
3720   enum tree_code codel = TREE_CODE (type);
3721   tree rhstype;
3722   enum tree_code coder;
3723   tree rname = NULL_TREE;
3724   bool objc_ok = false;
3725
3726   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3727     {
3728       tree selector;
3729       /* Change pointer to function to the function itself for
3730          diagnostics.  */
3731       if (TREE_CODE (function) == ADDR_EXPR
3732           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3733         function = TREE_OPERAND (function, 0);
3734
3735       /* Handle an ObjC selector specially for diagnostics.  */
3736       selector = objc_message_selector ();
3737       rname = function;
3738       if (selector && parmnum > 2)
3739         {
3740           rname = selector;
3741           parmnum -= 2;
3742         }
3743     }
3744
3745   /* This macro is used to emit diagnostics to ensure that all format
3746      strings are complete sentences, visible to gettext and checked at
3747      compile time.  */
3748 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3749   do {                                          \
3750     switch (errtype)                            \
3751       {                                         \
3752       case ic_argpass:                          \
3753         pedwarn (AR, parmnum, rname);           \
3754         break;                                  \
3755       case ic_argpass_nonproto:                 \
3756         warning (0, AR, parmnum, rname);                \
3757         break;                                  \
3758       case ic_assign:                           \
3759         pedwarn (AS);                           \
3760         break;                                  \
3761       case ic_init:                             \
3762         pedwarn (IN);                           \
3763         break;                                  \
3764       case ic_return:                           \
3765         pedwarn (RE);                           \
3766         break;                                  \
3767       default:                                  \
3768         gcc_unreachable ();                     \
3769       }                                         \
3770   } while (0)
3771
3772   STRIP_TYPE_NOPS (rhs);
3773
3774   if (optimize && TREE_CODE (rhs) == VAR_DECL
3775            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3776     rhs = decl_constant_value_for_broken_optimization (rhs);
3777
3778   rhstype = TREE_TYPE (rhs);
3779   coder = TREE_CODE (rhstype);
3780
3781   if (coder == ERROR_MARK)
3782     return error_mark_node;
3783
3784   if (c_dialect_objc ())
3785     {
3786       int parmno;
3787
3788       switch (errtype)
3789         {
3790         case ic_return:
3791           parmno = 0;
3792           break;
3793
3794         case ic_assign:
3795           parmno = -1;
3796           break;
3797
3798         case ic_init:
3799           parmno = -2;
3800           break;
3801
3802         default:
3803           parmno = parmnum;
3804           break;
3805         }
3806
3807       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3808     }
3809
3810   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3811     {
3812       overflow_warning (rhs);
3813       return rhs;
3814     }
3815
3816   if (coder == VOID_TYPE)
3817     {
3818       /* Except for passing an argument to an unprototyped function,
3819          this is a constraint violation.  When passing an argument to
3820          an unprototyped function, it is compile-time undefined;
3821          making it a constraint in that case was rejected in
3822          DR#252.  */
3823       error ("void value not ignored as it ought to be");
3824       return error_mark_node;
3825     }
3826   /* A type converts to a reference to it.
3827      This code doesn't fully support references, it's just for the
3828      special case of va_start and va_copy.  */
3829   if (codel == REFERENCE_TYPE
3830       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3831     {
3832       if (!lvalue_p (rhs))
3833         {
3834           error ("cannot pass rvalue to reference parameter");
3835           return error_mark_node;
3836         }
3837       if (!c_mark_addressable (rhs))
3838         return error_mark_node;
3839       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3840
3841       /* We already know that these two types are compatible, but they
3842          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3843          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3844          likely to be va_list, a typedef to __builtin_va_list, which
3845          is different enough that it will cause problems later.  */
3846       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3847         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3848
3849       rhs = build1 (NOP_EXPR, type, rhs);
3850       return rhs;
3851     }
3852   /* Some types can interconvert without explicit casts.  */
3853   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3854            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3855     return convert (type, rhs);
3856   /* Arithmetic types all interconvert, and enum is treated like int.  */
3857   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3858             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3859             || codel == BOOLEAN_TYPE)
3860            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3861                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3862                || coder == BOOLEAN_TYPE))
3863     return convert_and_check (type, rhs);
3864
3865   /* Conversion to a transparent union from its member types.
3866      This applies only to function arguments.  */
3867   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3868            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3869     {
3870       tree memb, marginal_memb = NULL_TREE;
3871
3872       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3873         {
3874           tree memb_type = TREE_TYPE (memb);
3875
3876           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3877                          TYPE_MAIN_VARIANT (rhstype)))
3878             break;
3879
3880           if (TREE_CODE (memb_type) != POINTER_TYPE)
3881             continue;
3882
3883           if (coder == POINTER_TYPE)
3884             {
3885               tree ttl = TREE_TYPE (memb_type);
3886               tree ttr = TREE_TYPE (rhstype);
3887
3888               /* Any non-function converts to a [const][volatile] void *
3889                  and vice versa; otherwise, targets must be the same.
3890                  Meanwhile, the lhs target must have all the qualifiers of
3891                  the rhs.  */
3892               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3893                   || comp_target_types (memb_type, rhstype))
3894                 {
3895                   /* If this type won't generate any warnings, use it.  */
3896                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3897                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3898                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3899                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3900                              == TYPE_QUALS (ttr))
3901                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3902                              == TYPE_QUALS (ttl))))
3903                     break;
3904
3905                   /* Keep looking for a better type, but remember this one.  */
3906                   if (!marginal_memb)
3907                     marginal_memb = memb;
3908                 }
3909             }
3910
3911           /* Can convert integer zero to any pointer type.  */
3912           if (null_pointer_constant_p (rhs))
3913             {
3914               rhs = null_pointer_node;
3915               break;
3916             }
3917         }
3918
3919       if (memb || marginal_memb)
3920         {
3921           if (!memb)
3922             {
3923               /* We have only a marginally acceptable member type;
3924                  it needs a warning.  */
3925               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3926               tree ttr = TREE_TYPE (rhstype);
3927
3928               /* Const and volatile mean something different for function
3929                  types, so the usual warnings are not appropriate.  */
3930               if (TREE_CODE (ttr) == FUNCTION_TYPE
3931                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3932                 {
3933                   /* Because const and volatile on functions are
3934                      restrictions that say the function will not do
3935                      certain things, it is okay to use a const or volatile
3936                      function where an ordinary one is wanted, but not
3937                      vice-versa.  */
3938                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3939                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3940                                             "makes qualified function "
3941                                             "pointer from unqualified"),
3942                                          G_("assignment makes qualified "
3943                                             "function pointer from "
3944                                             "unqualified"),
3945                                          G_("initialization makes qualified "
3946                                             "function pointer from "
3947                                             "unqualified"),
3948                                          G_("return makes qualified function "
3949                                             "pointer from unqualified"));
3950                 }
3951               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3952                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3953                                         "qualifiers from pointer target type"),
3954                                      G_("assignment discards qualifiers "
3955                                         "from pointer target type"),
3956                                      G_("initialization discards qualifiers "
3957                                         "from pointer target type"),
3958                                      G_("return discards qualifiers from "
3959                                         "pointer target type"));
3960
3961               memb = marginal_memb;
3962             }
3963
3964           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3965             pedwarn ("ISO C prohibits argument conversion to union type");
3966
3967           return build_constructor_single (type, memb, rhs);
3968         }
3969     }
3970
3971   /* Conversions among pointers */
3972   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3973            && (coder == codel))
3974     {
3975       tree ttl = TREE_TYPE (type);
3976       tree ttr = TREE_TYPE (rhstype);
3977       tree mvl = ttl;
3978       tree mvr = ttr;
3979       bool is_opaque_pointer;
3980       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3981
3982       if (TREE_CODE (mvl) != ARRAY_TYPE)
3983         mvl = TYPE_MAIN_VARIANT (mvl);
3984       if (TREE_CODE (mvr) != ARRAY_TYPE)
3985         mvr = TYPE_MAIN_VARIANT (mvr);
3986       /* Opaque pointers are treated like void pointers.  */
3987       is_opaque_pointer = (targetm.vector_opaque_p (type)
3988                            || targetm.vector_opaque_p (rhstype))
3989         && TREE_CODE (ttl) == VECTOR_TYPE
3990         && TREE_CODE (ttr) == VECTOR_TYPE;
3991
3992       /* C++ does not allow the implicit conversion void* -> T*.  However,
3993          for the purpose of reducing the number of false positives, we
3994          tolerate the special case of
3995
3996                 int *p = NULL;
3997
3998          where NULL is typically defined in C to be '(void *) 0'.  */
3999       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4000         warning (OPT_Wc___compat, "request for implicit conversion from "
4001                  "%qT to %qT not permitted in C++", rhstype, type);
4002
4003       /* Check if the right-hand side has a format attribute but the
4004          left-hand side doesn't.  */
4005       if (warn_missing_format_attribute
4006           && check_missing_format_attribute (type, rhstype))
4007         {
4008           switch (errtype)
4009           {
4010           case ic_argpass:
4011           case ic_argpass_nonproto:
4012             warning (OPT_Wmissing_format_attribute,
4013                      "argument %d of %qE might be "
4014                      "a candidate for a format attribute",
4015                      parmnum, rname);
4016             break;
4017           case ic_assign:
4018             warning (OPT_Wmissing_format_attribute,
4019                      "assignment left-hand side might be "
4020                      "a candidate for a format attribute");
4021             break;
4022           case ic_init:
4023             warning (OPT_Wmissing_format_attribute,
4024                      "initialization left-hand side might be "
4025                      "a candidate for a format attribute");
4026             break;
4027           case ic_return:
4028             warning (OPT_Wmissing_format_attribute,
4029                      "return type might be "
4030                      "a candidate for a format attribute");
4031             break;
4032           default:
4033             gcc_unreachable ();
4034           }
4035         }
4036
4037       /* Any non-function converts to a [const][volatile] void *
4038          and vice versa; otherwise, targets must be the same.
4039          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4040       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4041           || (target_cmp = comp_target_types (type, rhstype))
4042           || is_opaque_pointer
4043           || (c_common_unsigned_type (mvl)
4044               == c_common_unsigned_type (mvr)))
4045         {
4046           if (pedantic
4047               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4048                   ||
4049                   (VOID_TYPE_P (ttr)
4050                    && !null_pointer_constant_p (rhs)
4051                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4052             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4053                                     "%qE between function pointer "
4054                                     "and %<void *%>"),
4055                                  G_("ISO C forbids assignment between "
4056                                     "function pointer and %<void *%>"),
4057                                  G_("ISO C forbids initialization between "
4058                                     "function pointer and %<void *%>"),
4059                                  G_("ISO C forbids return between function "
4060                                     "pointer and %<void *%>"));
4061           /* Const and volatile mean something different for function types,
4062              so the usual warnings are not appropriate.  */
4063           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4064                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4065             {
4066               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4067                 {
4068                   /* Types differing only by the presence of the 'volatile'
4069                      qualifier are acceptable if the 'volatile' has been added
4070                      in by the Objective-C EH machinery.  */
4071                   if (!objc_type_quals_match (ttl, ttr))
4072                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4073                                             "qualifiers from pointer target type"),
4074                                          G_("assignment discards qualifiers "
4075                                             "from pointer target type"),
4076                                          G_("initialization discards qualifiers "
4077                                             "from pointer target type"),
4078                                          G_("return discards qualifiers from "
4079                                             "pointer target type"));
4080                 }
4081               /* If this is not a case of ignoring a mismatch in signedness,
4082                  no warning.  */
4083               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4084                        || target_cmp)
4085                 ;
4086               /* If there is a mismatch, do warn.  */
4087               else if (warn_pointer_sign)
4088                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4089                                         "%d of %qE differ in signedness"),
4090                                      G_("pointer targets in assignment "
4091                                         "differ in signedness"),
4092                                      G_("pointer targets in initialization "
4093                                         "differ in signedness"),
4094                                      G_("pointer targets in return differ "
4095                                         "in signedness"));
4096             }
4097           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4098                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4099             {
4100               /* Because const and volatile on functions are restrictions
4101                  that say the function will not do certain things,
4102                  it is okay to use a const or volatile function
4103                  where an ordinary one is wanted, but not vice-versa.  */
4104               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4105                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4106                                         "qualified function pointer "
4107                                         "from unqualified"),
4108                                      G_("assignment makes qualified function "
4109                                         "pointer from unqualified"),
4110                                      G_("initialization makes qualified "
4111                                         "function pointer from unqualified"),
4112                                      G_("return makes qualified function "
4113                                         "pointer from unqualified"));
4114             }
4115         }
4116       else
4117         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4118         if (!objc_ok)
4119           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4120                                   "incompatible pointer type"),
4121                                G_("assignment from incompatible pointer type"),
4122                                G_("initialization from incompatible "
4123                                   "pointer type"),
4124                                G_("return from incompatible pointer type"));
4125
4126       return convert (type, rhs);
4127     }
4128   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4129     {
4130       /* ??? This should not be an error when inlining calls to
4131          unprototyped functions.  */
4132       error ("invalid use of non-lvalue array");
4133       return error_mark_node;
4134     }
4135   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4136     {
4137       /* An explicit constant 0 can convert to a pointer,
4138          or one that results from arithmetic, even including
4139          a cast to integer type.  */
4140       if (!null_pointer_constant_p (rhs))
4141         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4142                                 "pointer from integer without a cast"),
4143                              G_("assignment makes pointer from integer "
4144                                 "without a cast"),
4145                              G_("initialization makes pointer from "
4146                                 "integer without a cast"),
4147                              G_("return makes pointer from integer "
4148                                 "without a cast"));
4149
4150       return convert (type, rhs);
4151     }
4152   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4153     {
4154       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4155                               "from pointer without a cast"),
4156                            G_("assignment makes integer from pointer "
4157                               "without a cast"),
4158                            G_("initialization makes integer from pointer "
4159                               "without a cast"),
4160                            G_("return makes integer from pointer "
4161                               "without a cast"));
4162       return convert (type, rhs);
4163     }
4164   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4165     return convert (type, rhs);
4166
4167   switch (errtype)
4168     {
4169     case ic_argpass:
4170     case ic_argpass_nonproto:
4171       /* ??? This should not be an error when inlining calls to
4172          unprototyped functions.  */
4173       error ("incompatible type for argument %d of %qE", parmnum, rname);
4174       break;
4175     case ic_assign:
4176       error ("incompatible types in assignment");
4177       break;
4178     case ic_init:
4179       error ("incompatible types in initialization");
4180       break;
4181     case ic_return:
4182       error ("incompatible types in return");
4183       break;
4184     default:
4185       gcc_unreachable ();
4186     }
4187
4188   return error_mark_node;
4189 }
4190
4191 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4192    is used for error and waring reporting and indicates which argument
4193    is being processed.  */
4194
4195 tree
4196 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4197 {
4198   tree ret, type;
4199
4200   /* If FN was prototyped, the value has been converted already
4201      in convert_arguments.  */
4202   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4203     return value;
4204
4205   type = TREE_TYPE (parm);
4206   ret = convert_for_assignment (type, value,
4207                                 ic_argpass_nonproto, fn,
4208                                 fn, argnum);
4209   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4210       && INTEGRAL_TYPE_P (type)
4211       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4212     ret = default_conversion (ret);
4213   return ret;
4214 }
4215 \f
4216 /* If VALUE is a compound expr all of whose expressions are constant, then
4217    return its value.  Otherwise, return error_mark_node.
4218
4219    This is for handling COMPOUND_EXPRs as initializer elements
4220    which is allowed with a warning when -pedantic is specified.  */
4221
4222 static tree
4223 valid_compound_expr_initializer (tree value, tree endtype)
4224 {
4225   if (TREE_CODE (value) == COMPOUND_EXPR)
4226     {
4227       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4228           == error_mark_node)
4229         return error_mark_node;
4230       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4231                                               endtype);
4232     }
4233   else if (!initializer_constant_valid_p (value, endtype))
4234     return error_mark_node;
4235   else
4236     return value;
4237 }
4238 \f
4239 /* Perform appropriate conversions on the initial value of a variable,
4240    store it in the declaration DECL,
4241    and print any error messages that are appropriate.
4242    If the init is invalid, store an ERROR_MARK.  */
4243
4244 void
4245 store_init_value (tree decl, tree init)
4246 {
4247   tree value, type;
4248
4249   /* If variable's type was invalidly declared, just ignore it.  */
4250
4251   type = TREE_TYPE (decl);
4252   if (TREE_CODE (type) == ERROR_MARK)
4253     return;
4254
4255   /* Digest the specified initializer into an expression.  */
4256
4257   value = digest_init (type, init, true, TREE_STATIC (decl));
4258
4259   /* Store the expression if valid; else report error.  */
4260
4261   if (!in_system_header
4262       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4263     warning (OPT_Wtraditional, "traditional C rejects automatic "
4264              "aggregate initialization");
4265
4266   DECL_INITIAL (decl) = value;
4267
4268   /* ANSI wants warnings about out-of-range constant initializers.  */
4269   STRIP_TYPE_NOPS (value);
4270   constant_expression_warning (value);
4271
4272   /* Check if we need to set array size from compound literal size.  */
4273   if (TREE_CODE (type) == ARRAY_TYPE
4274       && TYPE_DOMAIN (type) == 0
4275       && value != error_mark_node)
4276     {
4277       tree inside_init = init;
4278
4279       STRIP_TYPE_NOPS (inside_init);
4280       inside_init = fold (inside_init);
4281
4282       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4283         {
4284           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4285
4286           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4287             {
4288               /* For int foo[] = (int [3]){1}; we need to set array size
4289                  now since later on array initializer will be just the
4290                  brace enclosed list of the compound literal.  */
4291               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4292               layout_type (type);
4293               layout_decl (decl, 0);
4294             }
4295         }
4296     }
4297 }
4298 \f
4299 /* Methods for storing and printing names for error messages.  */
4300
4301 /* Implement a spelling stack that allows components of a name to be pushed
4302    and popped.  Each element on the stack is this structure.  */
4303
4304 struct spelling
4305 {
4306   int kind;
4307   union
4308     {
4309       unsigned HOST_WIDE_INT i;
4310       const char *s;
4311     } u;
4312 };
4313
4314 #define SPELLING_STRING 1
4315 #define SPELLING_MEMBER 2
4316 #define SPELLING_BOUNDS 3
4317
4318 static struct spelling *spelling;       /* Next stack element (unused).  */
4319 static struct spelling *spelling_base;  /* Spelling stack base.  */
4320 static int spelling_size;               /* Size of the spelling stack.  */
4321
4322 /* Macros to save and restore the spelling stack around push_... functions.
4323    Alternative to SAVE_SPELLING_STACK.  */
4324
4325 #define SPELLING_DEPTH() (spelling - spelling_base)
4326 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4327
4328 /* Push an element on the spelling stack with type KIND and assign VALUE
4329    to MEMBER.  */
4330
4331 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4332 {                                                                       \
4333   int depth = SPELLING_DEPTH ();                                        \
4334                                                                         \
4335   if (depth >= spelling_size)                                           \
4336     {                                                                   \
4337       spelling_size += 10;                                              \
4338       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4339                                   spelling_size);                       \
4340       RESTORE_SPELLING_DEPTH (depth);                                   \
4341     }                                                                   \
4342                                                                         \
4343   spelling->kind = (KIND);                                              \
4344   spelling->MEMBER = (VALUE);                                           \
4345   spelling++;                                                           \
4346 }
4347
4348 /* Push STRING on the stack.  Printed literally.  */
4349
4350 static void
4351 push_string (const char *string)
4352 {
4353   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4354 }
4355
4356 /* Push a member name on the stack.  Printed as '.' STRING.  */
4357
4358 static void
4359 push_member_name (tree decl)
4360 {
4361   const char *const string
4362     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4363   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4364 }
4365
4366 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4367
4368 static void
4369 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4370 {
4371   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4372 }
4373
4374 /* Compute the maximum size in bytes of the printed spelling.  */
4375
4376 static int
4377 spelling_length (void)
4378 {
4379   int size = 0;
4380   struct spelling *p;
4381
4382   for (p = spelling_base; p < spelling; p++)
4383     {
4384       if (p->kind == SPELLING_BOUNDS)
4385         size += 25;
4386       else
4387         size += strlen (p->u.s) + 1;
4388     }
4389
4390   return size;
4391 }
4392
4393 /* Print the spelling to BUFFER and return it.  */
4394
4395 static char *
4396 print_spelling (char *buffer)
4397 {
4398   char *d = buffer;
4399   struct spelling *p;
4400
4401   for (p = spelling_base; p < spelling; p++)
4402     if (p->kind == SPELLING_BOUNDS)
4403       {
4404         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4405         d += strlen (d);
4406       }
4407     else
4408       {
4409         const char *s;
4410         if (p->kind == SPELLING_MEMBER)
4411           *d++ = '.';
4412         for (s = p->u.s; (*d = *s++); d++)
4413           ;
4414       }
4415   *d++ = '\0';
4416   return buffer;
4417 }
4418
4419 /* Issue an error message for a bad initializer component.
4420    MSGID identifies the message.
4421    The component name is taken from the spelling stack.  */
4422
4423 void
4424 error_init (const char *msgid)
4425 {
4426   char *ofwhat;
4427
4428   error ("%s", _(msgid));
4429   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4430   if (*ofwhat)
4431     error ("(near initialization for %qs)", ofwhat);
4432 }
4433
4434 /* Issue a pedantic warning for a bad initializer component.
4435    MSGID identifies the message.
4436    The component name is taken from the spelling stack.  */
4437
4438 void
4439 pedwarn_init (const char *msgid)
4440 {
4441   char *ofwhat;
4442
4443   pedwarn ("%s", _(msgid));
4444   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4445   if (*ofwhat)
4446     pedwarn ("(near initialization for %qs)", ofwhat);
4447 }
4448
4449 /* Issue a warning for a bad initializer component.
4450    MSGID identifies the message.
4451    The component name is taken from the spelling stack.  */
4452
4453 static void
4454 warning_init (const char *msgid)
4455 {
4456   char *ofwhat;
4457
4458   warning (0, "%s", _(msgid));
4459   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4460   if (*ofwhat)
4461     warning (0, "(near initialization for %qs)", ofwhat);
4462 }
4463 \f
4464 /* If TYPE is an array type and EXPR is a parenthesized string
4465    constant, warn if pedantic that EXPR is being used to initialize an
4466    object of type TYPE.  */
4467
4468 void
4469 maybe_warn_string_init (tree type, struct c_expr expr)
4470 {
4471   if (pedantic
4472       && TREE_CODE (type) == ARRAY_TYPE
4473       && TREE_CODE (expr.value) == STRING_CST
4474       && expr.original_code != STRING_CST)
4475     pedwarn_init ("array initialized from parenthesized string constant");
4476 }
4477
4478 /* Digest the parser output INIT as an initializer for type TYPE.
4479    Return a C expression of type TYPE to represent the initial value.
4480
4481    If INIT is a string constant, STRICT_STRING is true if it is
4482    unparenthesized or we should not warn here for it being parenthesized.
4483    For other types of INIT, STRICT_STRING is not used.
4484
4485    REQUIRE_CONSTANT requests an error if non-constant initializers or
4486    elements are seen.  */
4487
4488 static tree
4489 digest_init (tree type, tree init, bool strict_string, int require_constant)
4490 {
4491   enum tree_code code = TREE_CODE (type);
4492   tree inside_init = init;
4493
4494   if (type == error_mark_node
4495       || !init
4496       || init == error_mark_node
4497       || TREE_TYPE (init) == error_mark_node)
4498     return error_mark_node;
4499
4500   STRIP_TYPE_NOPS (inside_init);
4501
4502   inside_init = fold (inside_init);
4503
4504   /* Initialization of an array of chars from a string constant
4505      optionally enclosed in braces.  */
4506
4507   if (code == ARRAY_TYPE && inside_init
4508       && TREE_CODE (inside_init) == STRING_CST)
4509     {
4510       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4511       /* Note that an array could be both an array of character type
4512          and an array of wchar_t if wchar_t is signed char or unsigned
4513          char.  */
4514       bool char_array = (typ1 == char_type_node
4515                          || typ1 == signed_char_type_node
4516                          || typ1 == unsigned_char_type_node);
4517       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4518       if (char_array || wchar_array)
4519         {
4520           struct c_expr expr;
4521           bool char_string;
4522           expr.value = inside_init;
4523           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4524           maybe_warn_string_init (type, expr);
4525
4526           char_string
4527             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4528                == char_type_node);
4529
4530           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4531                          TYPE_MAIN_VARIANT (type)))
4532             return inside_init;
4533
4534           if (!wchar_array && !char_string)
4535             {
4536               error_init ("char-array initialized from wide string");
4537               return error_mark_node;
4538             }
4539           if (char_string && !char_array)
4540             {
4541               error_init ("wchar_t-array initialized from non-wide string");
4542               return error_mark_node;
4543             }
4544
4545           TREE_TYPE (inside_init) = type;
4546           if (TYPE_DOMAIN (type) != 0
4547               && TYPE_SIZE (type) != 0
4548               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4549               /* Subtract 1 (or sizeof (wchar_t))
4550                  because it's ok to ignore the terminating null char
4551                  that is counted in the length of the constant.  */
4552               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4553                                        TREE_STRING_LENGTH (inside_init)
4554                                        - ((TYPE_PRECISION (typ1)
4555                                            != TYPE_PRECISION (char_type_node))
4556                                           ? (TYPE_PRECISION (wchar_type_node)
4557                                              / BITS_PER_UNIT)
4558                                           : 1)))
4559             pedwarn_init ("initializer-string for array of chars is too long");
4560
4561           return inside_init;
4562         }
4563       else if (INTEGRAL_TYPE_P (typ1))
4564         {
4565           error_init ("array of inappropriate type initialized "
4566                       "from string constant");
4567           return error_mark_node;
4568         }
4569     }
4570
4571   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4572      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4573      below and handle as a constructor.  */
4574   if (code == VECTOR_TYPE
4575       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4576       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4577       && TREE_CONSTANT (inside_init))
4578     {
4579       if (TREE_CODE (inside_init) == VECTOR_CST
4580           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4581                         TYPE_MAIN_VARIANT (type)))
4582         return inside_init;
4583
4584       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4585         {
4586           unsigned HOST_WIDE_INT ix;
4587           tree value;
4588           bool constant_p = true;
4589
4590           /* Iterate through elements and check if all constructor
4591              elements are *_CSTs.  */
4592           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4593             if (!CONSTANT_CLASS_P (value))
4594               {
4595                 constant_p = false;
4596                 break;
4597               }
4598
4599           if (constant_p)
4600             return build_vector_from_ctor (type,
4601                                            CONSTRUCTOR_ELTS (inside_init));
4602         }
4603     }
4604
4605   /* Any type can be initialized
4606      from an expression of the same type, optionally with braces.  */
4607
4608   if (inside_init && TREE_TYPE (inside_init) != 0
4609       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4610                      TYPE_MAIN_VARIANT (type))
4611           || (code == ARRAY_TYPE
4612               && comptypes (TREE_TYPE (inside_init), type))
4613           || (code == VECTOR_TYPE
4614               && comptypes (TREE_TYPE (inside_init), type))
4615           || (code == POINTER_TYPE
4616               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4617               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4618                             TREE_TYPE (type)))))
4619     {
4620       if (code == POINTER_TYPE)
4621         {
4622           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4623             {
4624               if (TREE_CODE (inside_init) == STRING_CST
4625                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4626                 inside_init = array_to_pointer_conversion (inside_init);
4627               else
4628                 {
4629                   error_init ("invalid use of non-lvalue array");
4630                   return error_mark_node;
4631                 }
4632             }
4633         }
4634
4635       if (code == VECTOR_TYPE)
4636         /* Although the types are compatible, we may require a
4637            conversion.  */
4638         inside_init = convert (type, inside_init);
4639
4640       if (require_constant && !flag_isoc99
4641           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4642         {
4643           /* As an extension, allow initializing objects with static storage
4644              duration with compound literals (which are then treated just as
4645              the brace enclosed list they contain).  */
4646           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4647           inside_init = DECL_INITIAL (decl);
4648         }
4649
4650       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4651           && TREE_CODE (inside_init) != CONSTRUCTOR)
4652         {
4653           error_init ("array initialized from non-constant array expression");
4654           return error_mark_node;
4655         }
4656
4657       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4658         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4659
4660       /* Compound expressions can only occur here if -pedantic or
4661          -pedantic-errors is specified.  In the later case, we always want
4662          an error.  In the former case, we simply want a warning.  */
4663       if (require_constant && pedantic
4664           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4665         {
4666           inside_init
4667             = valid_compound_expr_initializer (inside_init,
4668                                                TREE_TYPE (inside_init));
4669           if (inside_init == error_mark_node)
4670             error_init ("initializer element is not constant");
4671           else
4672             pedwarn_init ("initializer element is not constant");
4673           if (flag_pedantic_errors)
4674             inside_init = error_mark_node;
4675         }
4676       else if (require_constant
4677                && !initializer_constant_valid_p (inside_init,
4678                                                  TREE_TYPE (inside_init)))
4679         {
4680           error_init ("initializer element is not constant");
4681           inside_init = error_mark_node;
4682         }
4683
4684       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4685       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4686         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4687                                               NULL_TREE, 0);
4688       return inside_init;
4689     }
4690
4691   /* Handle scalar types, including conversions.  */
4692
4693   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4694       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4695       || code == VECTOR_TYPE)
4696     {
4697       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4698           && (TREE_CODE (init) == STRING_CST
4699               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4700         init = array_to_pointer_conversion (init);
4701       inside_init
4702         = convert_for_assignment (type, init, ic_init,
4703                                   NULL_TREE, NULL_TREE, 0);
4704
4705       /* Check to see if we have already given an error message.  */
4706       if (inside_init == error_mark_node)
4707         ;
4708       else if (require_constant && !TREE_CONSTANT (inside_init))
4709         {
4710           error_init ("initializer element is not constant");
4711           inside_init = error_mark_node;
4712         }
4713       else if (require_constant
4714                && !initializer_constant_valid_p (inside_init,
4715                                                  TREE_TYPE (inside_init)))
4716         {
4717           error_init ("initializer element is not computable at load time");
4718           inside_init = error_mark_node;
4719         }
4720
4721       return inside_init;
4722     }
4723
4724   /* Come here only for records and arrays.  */
4725
4726   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4727     {
4728       error_init ("variable-sized object may not be initialized");
4729       return error_mark_node;
4730     }
4731
4732   error_init ("invalid initializer");
4733   return error_mark_node;
4734 }
4735 \f
4736 /* Handle initializers that use braces.  */
4737
4738 /* Type of object we are accumulating a constructor for.
4739    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4740 static tree constructor_type;
4741
4742 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4743    left to fill.  */
4744 static tree constructor_fields;
4745
4746 /* For an ARRAY_TYPE, this is the specified index
4747    at which to store the next element we get.  */
4748 static tree constructor_index;
4749
4750 /* For an ARRAY_TYPE, this is the maximum index.  */
4751 static tree constructor_max_index;
4752
4753 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4754 static tree constructor_unfilled_fields;
4755
4756 /* For an ARRAY_TYPE, this is the index of the first element
4757    not yet written out.  */
4758 static tree constructor_unfilled_index;
4759
4760 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4761    This is so we can generate gaps between fields, when appropriate.  */
4762 static tree constructor_bit_index;
4763
4764 /* If we are saving up the elements rather than allocating them,
4765    this is the list of elements so far (in reverse order,
4766    most recent first).  */
4767 static VEC(constructor_elt,gc) *constructor_elements;
4768
4769 /* 1 if constructor should be incrementally stored into a constructor chain,
4770    0 if all the elements should be kept in AVL tree.  */
4771 static int constructor_incremental;
4772
4773 /* 1 if so far this constructor's elements are all compile-time constants.  */
4774 static int constructor_constant;
4775
4776 /* 1 if so far this constructor's elements are all valid address constants.  */
4777 static int constructor_simple;
4778
4779 /* 1 if this constructor is erroneous so far.  */
4780 static int constructor_erroneous;
4781
4782 /* Structure for managing pending initializer elements, organized as an
4783    AVL tree.  */
4784
4785 struct init_node
4786 {
4787   struct init_node *left, *right;
4788   struct init_node *parent;
4789   int balance;
4790   tree purpose;
4791   tree value;
4792 };
4793
4794 /* Tree of pending elements at this constructor level.
4795    These are elements encountered out of order
4796    which belong at places we haven't reached yet in actually
4797    writing the output.
4798    Will never hold tree nodes across GC runs.  */
4799 static struct init_node *constructor_pending_elts;
4800
4801 /* The SPELLING_DEPTH of this constructor.  */
4802 static int constructor_depth;
4803
4804 /* DECL node for which an initializer is being read.
4805    0 means we are reading a constructor expression
4806    such as (struct foo) {...}.  */
4807 static tree constructor_decl;
4808
4809 /* Nonzero if this is an initializer for a top-level decl.  */
4810 static int constructor_top_level;
4811
4812 /* Nonzero if there were any member designators in this initializer.  */
4813 static int constructor_designated;
4814
4815 /* Nesting depth of designator list.  */
4816 static int designator_depth;
4817
4818 /* Nonzero if there were diagnosed errors in this designator list.  */
4819 static int designator_erroneous;
4820
4821 \f
4822 /* This stack has a level for each implicit or explicit level of
4823    structuring in the initializer, including the outermost one.  It
4824    saves the values of most of the variables above.  */
4825
4826 struct constructor_range_stack;
4827
4828 struct constructor_stack
4829 {
4830   struct constructor_stack *next;
4831   tree type;
4832   tree fields;
4833   tree index;
4834   tree max_index;
4835   tree unfilled_index;
4836   tree unfilled_fields;
4837   tree bit_index;
4838   VEC(constructor_elt,gc) *elements;
4839   struct init_node *pending_elts;
4840   int offset;
4841   int depth;
4842   /* If value nonzero, this value should replace the entire
4843      constructor at this level.  */
4844   struct c_expr replacement_value;
4845   struct constructor_range_stack *range_stack;
4846   char constant;
4847   char simple;
4848   char implicit;
4849   char erroneous;
4850   char outer;
4851   char incremental;
4852   char designated;
4853 };
4854
4855 static struct constructor_stack *constructor_stack;
4856
4857 /* This stack represents designators from some range designator up to
4858    the last designator in the list.  */
4859
4860 struct constructor_range_stack
4861 {
4862   struct constructor_range_stack *next, *prev;
4863   struct constructor_stack *stack;
4864   tree range_start;
4865   tree index;
4866   tree range_end;
4867   tree fields;
4868 };
4869
4870 static struct constructor_range_stack *constructor_range_stack;
4871
4872 /* This stack records separate initializers that are nested.
4873    Nested initializers can't happen in ANSI C, but GNU C allows them
4874    in cases like { ... (struct foo) { ... } ... }.  */
4875
4876 struct initializer_stack
4877 {
4878   struct initializer_stack *next;
4879   tree decl;
4880   struct constructor_stack *constructor_stack;
4881   struct constructor_range_stack *constructor_range_stack;
4882   VEC(constructor_elt,gc) *elements;
4883   struct spelling *spelling;
4884   struct spelling *spelling_base;
4885   int spelling_size;
4886   char top_level;
4887   char require_constant_value;
4888   char require_constant_elements;
4889 };
4890
4891 static struct initializer_stack *initializer_stack;
4892 \f
4893 /* Prepare to parse and output the initializer for variable DECL.  */
4894
4895 void
4896 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4897 {
4898   const char *locus;
4899   struct initializer_stack *p = XNEW (struct initializer_stack);
4900
4901   p->decl = constructor_decl;
4902   p->require_constant_value = require_constant_value;
4903   p->require_constant_elements = require_constant_elements;
4904   p->constructor_stack = constructor_stack;
4905   p->constructor_range_stack = constructor_range_stack;
4906   p->elements = constructor_elements;
4907   p->spelling = spelling;
4908   p->spelling_base = spelling_base;
4909   p->spelling_size = spelling_size;
4910   p->top_level = constructor_top_level;
4911   p->next = initializer_stack;
4912   initializer_stack = p;
4913
4914   constructor_decl = decl;
4915   constructor_designated = 0;
4916   constructor_top_level = top_level;
4917
4918   if (decl != 0 && decl != error_mark_node)
4919     {
4920       require_constant_value = TREE_STATIC (decl);
4921       require_constant_elements
4922         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4923            /* For a scalar, you can always use any value to initialize,
4924               even within braces.  */
4925            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4926                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4927                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4928                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4929       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4930     }
4931   else
4932     {
4933       require_constant_value = 0;
4934       require_constant_elements = 0;
4935       locus = "(anonymous)";
4936     }
4937
4938   constructor_stack = 0;
4939   constructor_range_stack = 0;
4940
4941   missing_braces_mentioned = 0;
4942
4943   spelling_base = 0;
4944   spelling_size = 0;
4945   RESTORE_SPELLING_DEPTH (0);
4946
4947   if (locus)
4948     push_string (locus);
4949 }
4950
4951 void
4952 finish_init (void)
4953 {
4954   struct initializer_stack *p = initializer_stack;
4955
4956   /* Free the whole constructor stack of this initializer.  */
4957   while (constructor_stack)
4958     {
4959       struct constructor_stack *q = constructor_stack;
4960       constructor_stack = q->next;
4961       free (q);
4962     }
4963
4964   gcc_assert (!constructor_range_stack);
4965
4966   /* Pop back to the data of the outer initializer (if any).  */
4967   free (spelling_base);
4968
4969   constructor_decl = p->decl;
4970   require_constant_value = p->require_constant_value;
4971   require_constant_elements = p->require_constant_elements;
4972   constructor_stack = p->constructor_stack;
4973   constructor_range_stack = p->constructor_range_stack;
4974   constructor_elements = p->elements;
4975   spelling = p->spelling;
4976   spelling_base = p->spelling_base;
4977   spelling_size = p->spelling_size;
4978   constructor_top_level = p->top_level;
4979   initializer_stack = p->next;
4980   free (p);
4981 }
4982 \f
4983 /* Call here when we see the initializer is surrounded by braces.
4984    This is instead of a call to push_init_level;
4985    it is matched by a call to pop_init_level.
4986
4987    TYPE is the type to initialize, for a constructor expression.
4988    For an initializer for a decl, TYPE is zero.  */
4989
4990 void
4991 really_start_incremental_init (tree type)
4992 {
4993   struct constructor_stack *p = XNEW (struct constructor_stack);
4994
4995   if (type == 0)
4996     type = TREE_TYPE (constructor_decl);
4997
4998   if (targetm.vector_opaque_p (type))
4999     error ("opaque vector types cannot be initialized");
5000
5001   p->type = constructor_type;
5002   p->fields = constructor_fields;
5003   p->index = constructor_index;
5004   p->max_index = constructor_max_index;
5005   p->unfilled_index = constructor_unfilled_index;
5006   p->unfilled_fields = constructor_unfilled_fields;
5007   p->bit_index = constructor_bit_index;
5008   p->elements = constructor_elements;
5009   p->constant = constructor_constant;
5010   p->simple = constructor_simple;
5011   p->erroneous = constructor_erroneous;
5012   p->pending_elts = constructor_pending_elts;
5013   p->depth = constructor_depth;
5014   p->replacement_value.value = 0;
5015   p->replacement_value.original_code = ERROR_MARK;
5016   p->implicit = 0;
5017   p->range_stack = 0;
5018   p->outer = 0;
5019   p->incremental = constructor_incremental;
5020   p->designated = constructor_designated;
5021   p->next = 0;
5022   constructor_stack = p;
5023
5024   constructor_constant = 1;
5025   constructor_simple = 1;
5026   constructor_depth = SPELLING_DEPTH ();
5027   constructor_elements = 0;
5028   constructor_pending_elts = 0;
5029   constructor_type = type;
5030   constructor_incremental = 1;
5031   constructor_designated = 0;
5032   designator_depth = 0;
5033   designator_erroneous = 0;
5034
5035   if (TREE_CODE (constructor_type) == RECORD_TYPE
5036       || TREE_CODE (constructor_type) == UNION_TYPE)
5037     {
5038       constructor_fields = TYPE_FIELDS (constructor_type);
5039       /* Skip any nameless bit fields at the beginning.  */
5040       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5041              && DECL_NAME (constructor_fields) == 0)
5042         constructor_fields = TREE_CHAIN (constructor_fields);
5043
5044       constructor_unfilled_fields = constructor_fields;
5045       constructor_bit_index = bitsize_zero_node;
5046     }
5047   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5048     {
5049       if (TYPE_DOMAIN (constructor_type))
5050         {
5051           constructor_max_index
5052             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5053
5054           /* Detect non-empty initializations of zero-length arrays.  */
5055           if (constructor_max_index == NULL_TREE
5056               && TYPE_SIZE (constructor_type))
5057             constructor_max_index = build_int_cst (NULL_TREE, -1);
5058
5059           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5060              to initialize VLAs will cause a proper error; avoid tree
5061              checking errors as well by setting a safe value.  */
5062           if (constructor_max_index
5063               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5064             constructor_max_index = build_int_cst (NULL_TREE, -1);
5065
5066           constructor_index
5067             = convert (bitsizetype,
5068                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5069         }
5070       else
5071         {
5072           constructor_index = bitsize_zero_node;
5073           constructor_max_index = NULL_TREE;
5074         }
5075
5076       constructor_unfilled_index = constructor_index;
5077     }
5078   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5079     {
5080       /* Vectors are like simple fixed-size arrays.  */
5081       constructor_max_index =
5082         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5083       constructor_index = bitsize_zero_node;
5084       constructor_unfilled_index = constructor_index;
5085     }
5086   else
5087     {
5088       /* Handle the case of int x = {5}; */
5089       constructor_fields = constructor_type;
5090       constructor_unfilled_fields = constructor_type;
5091     }
5092 }
5093 \f
5094 /* Push down into a subobject, for initialization.
5095    If this is for an explicit set of braces, IMPLICIT is 0.
5096    If it is because the next element belongs at a lower level,
5097    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5098
5099 void
5100 push_init_level (int implicit)
5101 {
5102   struct constructor_stack *p;
5103   tree value = NULL_TREE;
5104
5105   /* If we've exhausted any levels that didn't have braces,
5106      pop them now.  If implicit == 1, this will have been done in
5107      process_init_element; do not repeat it here because in the case
5108      of excess initializers for an empty aggregate this leads to an
5109      infinite cycle of popping a level and immediately recreating
5110      it.  */
5111   if (implicit != 1)
5112     {
5113       while (constructor_stack->implicit)
5114         {
5115           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5116                || TREE_CODE (constructor_type) == UNION_TYPE)
5117               && constructor_fields == 0)
5118             process_init_element (pop_init_level (1));
5119           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5120                    && constructor_max_index
5121                    && tree_int_cst_lt (constructor_max_index,
5122                                        constructor_index))
5123             process_init_element (pop_init_level (1));
5124           else
5125             break;
5126         }
5127     }
5128
5129   /* Unless this is an explicit brace, we need to preserve previous
5130      content if any.  */
5131   if (implicit)
5132     {
5133       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5134            || TREE_CODE (constructor_type) == UNION_TYPE)
5135           && constructor_fields)
5136         value = find_init_member (constructor_fields);
5137       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5138         value = find_init_member (constructor_index);
5139     }
5140
5141   p = XNEW (struct constructor_stack);
5142   p->type = constructor_type;
5143   p->fields = constructor_fields;
5144   p->index = constructor_index;
5145   p->max_index = constructor_max_index;
5146   p->unfilled_index = constructor_unfilled_index;
5147   p->unfilled_fields = constructor_unfilled_fields;
5148   p->bit_index = constructor_bit_index;
5149   p->elements = constructor_elements;
5150   p->constant = constructor_constant;
5151   p->simple = constructor_simple;
5152   p->erroneous = constructor_erroneous;
5153   p->pending_elts = constructor_pending_elts;
5154   p->depth = constructor_depth;
5155   p->replacement_value.value = 0;
5156   p->replacement_value.original_code = ERROR_MARK;
5157   p->implicit = implicit;
5158   p->outer = 0;
5159   p->incremental = constructor_incremental;
5160   p->designated = constructor_designated;
5161   p->next = constructor_stack;
5162   p->range_stack = 0;
5163   constructor_stack = p;
5164
5165   constructor_constant = 1;
5166   constructor_simple = 1;
5167   constructor_depth = SPELLING_DEPTH ();
5168   constructor_elements = 0;
5169   constructor_incremental = 1;
5170   constructor_designated = 0;
5171   constructor_pending_elts = 0;
5172   if (!implicit)
5173     {
5174       p->range_stack = constructor_range_stack;
5175       constructor_range_stack = 0;
5176       designator_depth = 0;
5177       designator_erroneous = 0;
5178     }
5179
5180   /* Don't die if an entire brace-pair level is superfluous
5181      in the containing level.  */
5182   if (constructor_type == 0)
5183     ;
5184   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5185            || TREE_CODE (constructor_type) == UNION_TYPE)
5186     {
5187       /* Don't die if there are extra init elts at the end.  */
5188       if (constructor_fields == 0)
5189         constructor_type = 0;
5190       else
5191         {
5192           constructor_type = TREE_TYPE (constructor_fields);
5193           push_member_name (constructor_fields);
5194           constructor_depth++;
5195         }
5196     }
5197   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5198     {
5199       constructor_type = TREE_TYPE (constructor_type);
5200       push_array_bounds (tree_low_cst (constructor_index, 1));
5201       constructor_depth++;
5202     }
5203
5204   if (constructor_type == 0)
5205     {
5206       error_init ("extra brace group at end of initializer");
5207       constructor_fields = 0;
5208       constructor_unfilled_fields = 0;
5209       return;
5210     }
5211
5212   if (value && TREE_CODE (value) == CONSTRUCTOR)
5213     {
5214       constructor_constant = TREE_CONSTANT (value);
5215       constructor_simple = TREE_STATIC (value);
5216       constructor_elements = CONSTRUCTOR_ELTS (value);
5217       if (!VEC_empty (constructor_elt, constructor_elements)
5218           && (TREE_CODE (constructor_type) == RECORD_TYPE
5219               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5220         set_nonincremental_init ();
5221     }
5222
5223   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5224     {
5225       missing_braces_mentioned = 1;
5226       warning_init ("missing braces around initializer");
5227     }
5228
5229   if (TREE_CODE (constructor_type) == RECORD_TYPE
5230            || TREE_CODE (constructor_type) == UNION_TYPE)
5231     {
5232       constructor_fields = TYPE_FIELDS (constructor_type);
5233       /* Skip any nameless bit fields at the beginning.  */
5234       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5235              && DECL_NAME (constructor_fields) == 0)
5236         constructor_fields = TREE_CHAIN (constructor_fields);
5237
5238       constructor_unfilled_fields = constructor_fields;
5239       constructor_bit_index = bitsize_zero_node;
5240     }
5241   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5242     {
5243       /* Vectors are like simple fixed-size arrays.  */
5244       constructor_max_index =
5245         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5246       constructor_index = convert (bitsizetype, integer_zero_node);
5247       constructor_unfilled_index = constructor_index;
5248     }
5249   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5250     {
5251       if (TYPE_DOMAIN (constructor_type))
5252         {
5253           constructor_max_index
5254             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5255
5256           /* Detect non-empty initializations of zero-length arrays.  */
5257           if (constructor_max_index == NULL_TREE
5258               && TYPE_SIZE (constructor_type))
5259             constructor_max_index = build_int_cst (NULL_TREE, -1);
5260
5261           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5262              to initialize VLAs will cause a proper error; avoid tree
5263              checking errors as well by setting a safe value.  */
5264           if (constructor_max_index
5265               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5266             constructor_max_index = build_int_cst (NULL_TREE, -1);
5267
5268           constructor_index
5269             = convert (bitsizetype,
5270                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5271         }
5272       else
5273         constructor_index = bitsize_zero_node;
5274
5275       constructor_unfilled_index = constructor_index;
5276       if (value && TREE_CODE (value) == STRING_CST)
5277         {
5278           /* We need to split the char/wchar array into individual
5279              characters, so that we don't have to special case it
5280              everywhere.  */
5281           set_nonincremental_init_from_string (value);
5282         }
5283     }
5284   else
5285     {
5286       if (constructor_type != error_mark_node)
5287         warning_init ("braces around scalar initializer");
5288       constructor_fields = constructor_type;
5289       constructor_unfilled_fields = constructor_type;
5290     }
5291 }
5292
5293 /* At the end of an implicit or explicit brace level,
5294    finish up that level of constructor.  If a single expression
5295    with redundant braces initialized that level, return the
5296    c_expr structure for that expression.  Otherwise, the original_code
5297    element is set to ERROR_MARK.
5298    If we were outputting the elements as they are read, return 0 as the value
5299    from inner levels (process_init_element ignores that),
5300    but return error_mark_node as the value from the outermost level
5301    (that's what we want to put in DECL_INITIAL).
5302    Otherwise, return a CONSTRUCTOR expression as the value.  */
5303
5304 struct c_expr
5305 pop_init_level (int implicit)
5306 {
5307   struct constructor_stack *p;
5308   struct c_expr ret;
5309   ret.value = 0;
5310   ret.original_code = ERROR_MARK;
5311
5312   if (implicit == 0)
5313     {
5314       /* When we come to an explicit close brace,
5315          pop any inner levels that didn't have explicit braces.  */
5316       while (constructor_stack->implicit)
5317         process_init_element (pop_init_level (1));
5318
5319       gcc_assert (!constructor_range_stack);
5320     }
5321
5322   /* Now output all pending elements.  */
5323   constructor_incremental = 1;
5324   output_pending_init_elements (1);
5325
5326   p = constructor_stack;
5327
5328   /* Error for initializing a flexible array member, or a zero-length
5329      array member in an inappropriate context.  */
5330   if (constructor_type && constructor_fields
5331       && TREE_CODE (constructor_type) == ARRAY_TYPE
5332       && TYPE_DOMAIN (constructor_type)
5333       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5334     {
5335       /* Silently discard empty initializations.  The parser will
5336          already have pedwarned for empty brackets.  */
5337       if (integer_zerop (constructor_unfilled_index))
5338         constructor_type = NULL_TREE;
5339       else
5340         {
5341           gcc_assert (!TYPE_SIZE (constructor_type));
5342
5343           if (constructor_depth > 2)
5344             error_init ("initialization of flexible array member in a nested context");
5345           else if (pedantic)
5346             pedwarn_init ("initialization of a flexible array member");
5347
5348           /* We have already issued an error message for the existence
5349              of a flexible array member not at the end of the structure.
5350              Discard the initializer so that we do not die later.  */
5351           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5352             constructor_type = NULL_TREE;
5353         }
5354     }
5355
5356   /* Warn when some struct elements are implicitly initialized to zero.  */
5357   if (warn_missing_field_initializers
5358       && constructor_type
5359       && TREE_CODE (constructor_type) == RECORD_TYPE
5360       && constructor_unfilled_fields)
5361     {
5362         /* Do not warn for flexible array members or zero-length arrays.  */
5363         while (constructor_unfilled_fields
5364                && (!DECL_SIZE (constructor_unfilled_fields)
5365                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5366           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5367
5368         /* Do not warn if this level of the initializer uses member
5369            designators; it is likely to be deliberate.  */
5370         if (constructor_unfilled_fields && !constructor_designated)
5371           {
5372             push_member_name (constructor_unfilled_fields);
5373             warning_init ("missing initializer");
5374             RESTORE_SPELLING_DEPTH (constructor_depth);
5375           }
5376     }
5377
5378   /* Pad out the end of the structure.  */
5379   if (p->replacement_value.value)
5380     /* If this closes a superfluous brace pair,
5381        just pass out the element between them.  */
5382     ret = p->replacement_value;
5383   else if (constructor_type == 0)
5384     ;
5385   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5386            && TREE_CODE (constructor_type) != UNION_TYPE
5387            && TREE_CODE (constructor_type) != ARRAY_TYPE
5388            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5389     {
5390       /* A nonincremental scalar initializer--just return
5391          the element, after verifying there is just one.  */
5392       if (VEC_empty (constructor_elt,constructor_elements))
5393         {
5394           if (!constructor_erroneous)
5395             error_init ("empty scalar initializer");
5396           ret.value = error_mark_node;
5397         }
5398       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5399         {
5400           error_init ("extra elements in scalar initializer");
5401           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5402         }
5403       else
5404         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5405     }
5406   else
5407     {
5408       if (constructor_erroneous)
5409         ret.value = error_mark_node;
5410       else
5411         {
5412           ret.value = build_constructor (constructor_type,
5413                                          constructor_elements);
5414           if (constructor_constant)
5415             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5416           if (constructor_constant && constructor_simple)
5417             TREE_STATIC (ret.value) = 1;
5418         }
5419     }
5420
5421   constructor_type = p->type;
5422   constructor_fields = p->fields;
5423   constructor_index = p->index;
5424   constructor_max_index = p->max_index;
5425   constructor_unfilled_index = p->unfilled_index;
5426   constructor_unfilled_fields = p->unfilled_fields;
5427   constructor_bit_index = p->bit_index;
5428   constructor_elements = p->elements;
5429   constructor_constant = p->constant;
5430   constructor_simple = p->simple;
5431   constructor_erroneous = p->erroneous;
5432   constructor_incremental = p->incremental;
5433   constructor_designated = p->designated;
5434   constructor_pending_elts = p->pending_elts;
5435   constructor_depth = p->depth;
5436   if (!p->implicit)
5437     constructor_range_stack = p->range_stack;
5438   RESTORE_SPELLING_DEPTH (constructor_depth);
5439
5440   constructor_stack = p->next;
5441   free (p);
5442
5443   if (ret.value == 0 && constructor_stack == 0)
5444     ret.value = error_mark_node;
5445   return ret;
5446 }
5447
5448 /* Common handling for both array range and field name designators.
5449    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5450
5451 static int
5452 set_designator (int array)
5453 {
5454   tree subtype;
5455   enum tree_code subcode;
5456
5457   /* Don't die if an entire brace-pair level is superfluous
5458      in the containing level.  */
5459   if (constructor_type == 0)
5460     return 1;
5461
5462   /* If there were errors in this designator list already, bail out
5463      silently.  */
5464   if (designator_erroneous)
5465     return 1;
5466
5467   if (!designator_depth)
5468     {
5469       gcc_assert (!constructor_range_stack);
5470
5471       /* Designator list starts at the level of closest explicit
5472          braces.  */
5473       while (constructor_stack->implicit)
5474         process_init_element (pop_init_level (1));
5475       constructor_designated = 1;
5476       return 0;
5477     }
5478
5479   switch (TREE_CODE (constructor_type))
5480     {
5481     case  RECORD_TYPE:
5482     case  UNION_TYPE:
5483       subtype = TREE_TYPE (constructor_fields);
5484       if (subtype != error_mark_node)
5485         subtype = TYPE_MAIN_VARIANT (subtype);
5486       break;
5487     case ARRAY_TYPE:
5488       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5489       break;
5490     default:
5491       gcc_unreachable ();
5492     }
5493
5494   subcode = TREE_CODE (subtype);
5495   if (array && subcode != ARRAY_TYPE)
5496     {
5497       error_init ("array index in non-array initializer");
5498       return 1;
5499     }
5500   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5501     {
5502       error_init ("field name not in record or union initializer");
5503       return 1;
5504     }
5505
5506   constructor_designated = 1;
5507   push_init_level (2);
5508   return 0;
5509 }
5510
5511 /* If there are range designators in designator list, push a new designator
5512    to constructor_range_stack.  RANGE_END is end of such stack range or
5513    NULL_TREE if there is no range designator at this level.  */
5514
5515 static void
5516 push_range_stack (tree range_end)
5517 {
5518   struct constructor_range_stack *p;
5519
5520   p = GGC_NEW (struct constructor_range_stack);
5521   p->prev = constructor_range_stack;
5522   p->next = 0;
5523   p->fields = constructor_fields;
5524   p->range_start = constructor_index;
5525   p->index = constructor_index;
5526   p->stack = constructor_stack;
5527   p->range_end = range_end;
5528   if (constructor_range_stack)
5529     constructor_range_stack->next = p;
5530   constructor_range_stack = p;
5531 }
5532
5533 /* Within an array initializer, specify the next index to be initialized.
5534    FIRST is that index.  If LAST is nonzero, then initialize a range
5535    of indices, running from FIRST through LAST.  */
5536
5537 void
5538 set_init_index (tree first, tree last)
5539 {
5540   if (set_designator (1))
5541     return;
5542
5543   designator_erroneous = 1;
5544
5545   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5546       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5547     {
5548       error_init ("array index in initializer not of integer type");
5549       return;
5550     }
5551
5552   if (TREE_CODE (first) != INTEGER_CST)
5553     error_init ("nonconstant array index in initializer");
5554   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5555     error_init ("nonconstant array index in initializer");
5556   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5557     error_init ("array index in non-array initializer");
5558   else if (tree_int_cst_sgn (first) == -1)
5559     error_init ("array index in initializer exceeds array bounds");
5560   else if (constructor_max_index
5561            && tree_int_cst_lt (constructor_max_index, first))
5562     error_init ("array index in initializer exceeds array bounds");
5563   else
5564     {
5565       constructor_index = convert (bitsizetype, first);
5566
5567       if (last)
5568         {
5569           if (tree_int_cst_equal (first, last))
5570             last = 0;
5571           else if (tree_int_cst_lt (last, first))
5572             {
5573               error_init ("empty index range in initializer");
5574               last = 0;
5575             }
5576           else
5577             {
5578               last = convert (bitsizetype, last);
5579               if (constructor_max_index != 0
5580                   && tree_int_cst_lt (constructor_max_index, last))
5581                 {
5582                   error_init ("array index range in initializer exceeds array bounds");
5583                   last = 0;
5584                 }
5585             }
5586         }
5587
5588       designator_depth++;
5589       designator_erroneous = 0;
5590       if (constructor_range_stack || last)
5591         push_range_stack (last);
5592     }
5593 }
5594
5595 /* Within a struct initializer, specify the next field to be initialized.  */
5596
5597 void
5598 set_init_label (tree fieldname)
5599 {
5600   tree tail;
5601
5602   if (set_designator (0))
5603     return;
5604
5605   designator_erroneous = 1;
5606
5607   if (TREE_CODE (constructor_type) != RECORD_TYPE
5608       && TREE_CODE (constructor_type) != UNION_TYPE)
5609     {
5610       error_init ("field name not in record or union initializer");
5611       return;
5612     }
5613
5614   for (tail = TYPE_FIELDS (constructor_type); tail;
5615        tail = TREE_CHAIN (tail))
5616     {
5617       if (DECL_NAME (tail) == fieldname)
5618         break;
5619     }
5620
5621   if (tail == 0)
5622     error ("unknown field %qE specified in initializer", fieldname);
5623   else
5624     {
5625       constructor_fields = tail;
5626       designator_depth++;
5627       designator_erroneous = 0;
5628       if (constructor_range_stack)
5629         push_range_stack (NULL_TREE);
5630     }
5631 }
5632 \f
5633 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5634    identifies the initializer, either array index or field in a structure.
5635    VALUE is the value of that index or field.  */
5636
5637 static void
5638 add_pending_init (tree purpose, tree value)
5639 {
5640   struct init_node *p, **q, *r;
5641
5642   q = &constructor_pending_elts;
5643   p = 0;
5644
5645   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5646     {
5647       while (*q != 0)
5648         {
5649           p = *q;
5650           if (tree_int_cst_lt (purpose, p->purpose))
5651             q = &p->left;
5652           else if (tree_int_cst_lt (p->purpose, purpose))
5653             q = &p->right;
5654           else
5655             {
5656               if (TREE_SIDE_EFFECTS (p->value))
5657                 warning_init ("initialized field with side-effects overwritten");
5658               p->value = value;
5659               return;
5660             }
5661         }
5662     }
5663   else
5664     {
5665       tree bitpos;
5666
5667       bitpos = bit_position (purpose);
5668       while (*q != NULL)
5669         {
5670           p = *q;
5671           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5672             q = &p->left;
5673           else if (p->purpose != purpose)
5674             q = &p->right;
5675           else
5676             {
5677               if (TREE_SIDE_EFFECTS (p->value))
5678                 warning_init ("initialized field with side-effects overwritten");
5679               p->value = value;
5680               return;
5681             }
5682         }
5683     }
5684
5685   r = GGC_NEW (struct init_node);
5686   r->purpose = purpose;
5687   r->value = value;
5688
5689   *q = r;
5690   r->parent = p;
5691   r->left = 0;
5692   r->right = 0;
5693   r->balance = 0;
5694
5695   while (p)
5696     {
5697       struct init_node *s;
5698
5699       if (r == p->left)
5700         {
5701           if (p->balance == 0)
5702             p->balance = -1;
5703           else if (p->balance < 0)
5704             {
5705               if (r->balance < 0)
5706                 {
5707                   /* L rotation.  */
5708                   p->left = r->right;
5709                   if (p->left)
5710                     p->left->parent = p;
5711                   r->right = p;
5712
5713                   p->balance = 0;
5714                   r->balance = 0;
5715
5716                   s = p->parent;
5717                   p->parent = r;
5718                   r->parent = s;
5719                   if (s)
5720                     {
5721                       if (s->left == p)
5722                         s->left = r;
5723                       else
5724                         s->right = r;
5725                     }
5726                   else
5727                     constructor_pending_elts = r;
5728                 }
5729               else
5730                 {
5731                   /* LR rotation.  */
5732                   struct init_node *t = r->right;
5733
5734                   r->right = t->left;
5735                   if (r->right)
5736                     r->right->parent = r;
5737                   t->left = r;
5738
5739                   p->left = t->right;
5740                   if (p->left)
5741                     p->left->parent = p;
5742                   t->right = p;
5743
5744                   p->balance = t->balance < 0;
5745                   r->balance = -(t->balance > 0);
5746                   t->balance = 0;
5747
5748                   s = p->parent;
5749                   p->parent = t;
5750                   r->parent = t;
5751                   t->parent = s;
5752                   if (s)
5753                     {
5754                       if (s->left == p)
5755                         s->left = t;
5756                       else
5757                         s->right = t;
5758                     }
5759                   else
5760                     constructor_pending_elts = t;
5761                 }
5762               break;
5763             }
5764           else
5765             {
5766               /* p->balance == +1; growth of left side balances the node.  */
5767               p->balance = 0;
5768               break;
5769             }
5770         }
5771       else /* r == p->right */
5772         {
5773           if (p->balance == 0)
5774             /* Growth propagation from right side.  */
5775             p->balance++;
5776           else if (p->balance > 0)
5777             {
5778               if (r->balance > 0)
5779                 {
5780                   /* R rotation.  */
5781                   p->right = r->left;
5782                   if (p->right)
5783                     p->right->parent = p;
5784                   r->left = p;
5785
5786                   p->balance = 0;
5787                   r->balance = 0;
5788
5789                   s = p->parent;
5790                   p->parent = r;
5791                   r->parent = s;
5792                   if (s)
5793                     {
5794                       if (s->left == p)
5795                         s->left = r;
5796                       else
5797                         s->right = r;
5798                     }
5799                   else
5800                     constructor_pending_elts = r;
5801                 }
5802               else /* r->balance == -1 */
5803                 {
5804                   /* RL rotation */
5805                   struct init_node *t = r->left;
5806
5807                   r->left = t->right;
5808                   if (r->left)
5809                     r->left->parent = r;
5810                   t->right = r;
5811
5812                   p->right = t->left;
5813                   if (p->right)
5814                     p->right->parent = p;
5815                   t->left = p;
5816
5817                   r->balance = (t->balance < 0);
5818                   p->balance = -(t->balance > 0);
5819                   t->balance = 0;
5820
5821                   s = p->parent;
5822                   p->parent = t;
5823                   r->parent = t;
5824                   t->parent = s;
5825                   if (s)
5826                     {
5827                       if (s->left == p)
5828                         s->left = t;
5829                       else
5830                         s->right = t;
5831                     }
5832                   else
5833                     constructor_pending_elts = t;
5834                 }
5835               break;
5836             }
5837           else
5838             {
5839               /* p->balance == -1; growth of right side balances the node.  */
5840               p->balance = 0;
5841               break;
5842             }
5843         }
5844
5845       r = p;
5846       p = p->parent;
5847     }
5848 }
5849
5850 /* Build AVL tree from a sorted chain.  */
5851
5852 static void
5853 set_nonincremental_init (void)
5854 {
5855   unsigned HOST_WIDE_INT ix;
5856   tree index, value;
5857
5858   if (TREE_CODE (constructor_type) != RECORD_TYPE
5859       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5860     return;
5861
5862   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5863     add_pending_init (index, value);
5864   constructor_elements = 0;
5865   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5866     {
5867       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5868       /* Skip any nameless bit fields at the beginning.  */
5869       while (constructor_unfilled_fields != 0
5870              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5871              && DECL_NAME (constructor_unfilled_fields) == 0)
5872         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5873
5874     }
5875   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5876     {
5877       if (TYPE_DOMAIN (constructor_type))
5878         constructor_unfilled_index
5879             = convert (bitsizetype,
5880                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5881       else
5882         constructor_unfilled_index = bitsize_zero_node;
5883     }
5884   constructor_incremental = 0;
5885 }
5886
5887 /* Build AVL tree from a string constant.  */
5888
5889 static void
5890 set_nonincremental_init_from_string (tree str)
5891 {
5892   tree value, purpose, type;
5893   HOST_WIDE_INT val[2];
5894   const char *p, *end;
5895   int byte, wchar_bytes, charwidth, bitpos;
5896
5897   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5898
5899   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5900       == TYPE_PRECISION (char_type_node))
5901     wchar_bytes = 1;
5902   else
5903     {
5904       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5905                   == TYPE_PRECISION (wchar_type_node));
5906       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5907     }
5908   charwidth = TYPE_PRECISION (char_type_node);
5909   type = TREE_TYPE (constructor_type);
5910   p = TREE_STRING_POINTER (str);
5911   end = p + TREE_STRING_LENGTH (str);
5912
5913   for (purpose = bitsize_zero_node;
5914        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5915        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5916     {
5917       if (wchar_bytes == 1)
5918         {
5919           val[1] = (unsigned char) *p++;
5920           val[0] = 0;
5921         }
5922       else
5923         {
5924           val[0] = 0;
5925           val[1] = 0;
5926           for (byte = 0; byte < wchar_bytes; byte++)
5927             {
5928               if (BYTES_BIG_ENDIAN)
5929                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5930               else
5931                 bitpos = byte * charwidth;
5932               val[bitpos < HOST_BITS_PER_WIDE_INT]
5933                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5934                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5935             }
5936         }
5937
5938       if (!TYPE_UNSIGNED (type))
5939         {
5940           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5941           if (bitpos < HOST_BITS_PER_WIDE_INT)
5942             {
5943               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5944                 {
5945                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5946                   val[0] = -1;
5947                 }
5948             }
5949           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5950             {
5951               if (val[1] < 0)
5952                 val[0] = -1;
5953             }
5954           else if (val[0] & (((HOST_WIDE_INT) 1)
5955                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5956             val[0] |= ((HOST_WIDE_INT) -1)
5957                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5958         }
5959
5960       value = build_int_cst_wide (type, val[1], val[0]);
5961       add_pending_init (purpose, value);
5962     }
5963
5964   constructor_incremental = 0;
5965 }
5966
5967 /* Return value of FIELD in pending initializer or zero if the field was
5968    not initialized yet.  */
5969
5970 static tree
5971 find_init_member (tree field)
5972 {
5973   struct init_node *p;
5974
5975   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5976     {
5977       if (constructor_incremental
5978           && tree_int_cst_lt (field, constructor_unfilled_index))
5979         set_nonincremental_init ();
5980
5981       p = constructor_pending_elts;
5982       while (p)
5983         {
5984           if (tree_int_cst_lt (field, p->purpose))
5985             p = p->left;
5986           else if (tree_int_cst_lt (p->purpose, field))
5987             p = p->right;
5988           else
5989             return p->value;
5990         }
5991     }
5992   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5993     {
5994       tree bitpos = bit_position (field);
5995
5996       if (constructor_incremental
5997           && (!constructor_unfilled_fields
5998               || tree_int_cst_lt (bitpos,
5999                                   bit_position (constructor_unfilled_fields))))
6000         set_nonincremental_init ();
6001
6002       p = constructor_pending_elts;
6003       while (p)
6004         {
6005           if (field == p->purpose)
6006             return p->value;
6007           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6008             p = p->left;
6009           else
6010             p = p->right;
6011         }
6012     }
6013   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6014     {
6015       if (!VEC_empty (constructor_elt, constructor_elements)
6016           && (VEC_last (constructor_elt, constructor_elements)->index
6017               == field))
6018         return VEC_last (constructor_elt, constructor_elements)->value;
6019     }
6020   return 0;
6021 }
6022
6023 /* "Output" the next constructor element.
6024    At top level, really output it to assembler code now.
6025    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6026    TYPE is the data type that the containing data type wants here.
6027    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6028    If VALUE is a string constant, STRICT_STRING is true if it is
6029    unparenthesized or we should not warn here for it being parenthesized.
6030    For other types of VALUE, STRICT_STRING is not used.
6031
6032    PENDING if non-nil means output pending elements that belong
6033    right after this element.  (PENDING is normally 1;
6034    it is 0 while outputting pending elements, to avoid recursion.)  */
6035
6036 static void
6037 output_init_element (tree value, bool strict_string, tree type, tree field,
6038                      int pending)
6039 {
6040   constructor_elt *celt;
6041
6042   if (type == error_mark_node || value == error_mark_node)
6043     {
6044       constructor_erroneous = 1;
6045       return;
6046     }
6047   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6048       && (TREE_CODE (value) == STRING_CST
6049           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6050       && !(TREE_CODE (value) == STRING_CST
6051            && TREE_CODE (type) == ARRAY_TYPE
6052            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6053       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6054                      TYPE_MAIN_VARIANT (type)))
6055     value = array_to_pointer_conversion (value);
6056
6057   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6058       && require_constant_value && !flag_isoc99 && pending)
6059     {
6060       /* As an extension, allow initializing objects with static storage
6061          duration with compound literals (which are then treated just as
6062          the brace enclosed list they contain).  */
6063       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6064       value = DECL_INITIAL (decl);
6065     }
6066
6067   if (value == error_mark_node)
6068     constructor_erroneous = 1;
6069   else if (!TREE_CONSTANT (value))
6070     constructor_constant = 0;
6071   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6072            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6073                 || TREE_CODE (constructor_type) == UNION_TYPE)
6074                && DECL_C_BIT_FIELD (field)
6075                && TREE_CODE (value) != INTEGER_CST))
6076     constructor_simple = 0;
6077
6078   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6079     {
6080       if (require_constant_value)
6081         {
6082           error_init ("initializer element is not constant");
6083           value = error_mark_node;
6084         }
6085       else if (require_constant_elements)
6086         pedwarn ("initializer element is not computable at load time");
6087     }
6088
6089   /* If this field is empty (and not at the end of structure),
6090      don't do anything other than checking the initializer.  */
6091   if (field
6092       && (TREE_TYPE (field) == error_mark_node
6093           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6094               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6095               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6096                   || TREE_CHAIN (field)))))
6097     return;
6098
6099   value = digest_init (type, value, strict_string, require_constant_value);
6100   if (value == error_mark_node)
6101     {
6102       constructor_erroneous = 1;
6103       return;
6104     }
6105
6106   /* If this element doesn't come next in sequence,
6107      put it on constructor_pending_elts.  */
6108   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6109       && (!constructor_incremental
6110           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6111     {
6112       if (constructor_incremental
6113           && tree_int_cst_lt (field, constructor_unfilled_index))
6114         set_nonincremental_init ();
6115
6116       add_pending_init (field, value);
6117       return;
6118     }
6119   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6120            && (!constructor_incremental
6121                || field != constructor_unfilled_fields))
6122     {
6123       /* We do this for records but not for unions.  In a union,
6124          no matter which field is specified, it can be initialized
6125          right away since it starts at the beginning of the union.  */
6126       if (constructor_incremental)
6127         {
6128           if (!constructor_unfilled_fields)
6129             set_nonincremental_init ();
6130           else
6131             {
6132               tree bitpos, unfillpos;
6133
6134               bitpos = bit_position (field);
6135               unfillpos = bit_position (constructor_unfilled_fields);
6136
6137               if (tree_int_cst_lt (bitpos, unfillpos))
6138                 set_nonincremental_init ();
6139             }
6140         }
6141
6142       add_pending_init (field, value);
6143       return;
6144     }
6145   else if (TREE_CODE (constructor_type) == UNION_TYPE
6146            && !VEC_empty (constructor_elt, constructor_elements))
6147     {
6148       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6149                                        constructor_elements)->value))
6150         warning_init ("initialized field with side-effects overwritten");
6151
6152       /* We can have just one union field set.  */
6153       constructor_elements = 0;
6154     }
6155
6156   /* Otherwise, output this element either to
6157      constructor_elements or to the assembler file.  */
6158
6159   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6160   celt->index = field;
6161   celt->value = value;
6162
6163   /* Advance the variable that indicates sequential elements output.  */
6164   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6165     constructor_unfilled_index
6166       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6167                     bitsize_one_node);
6168   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6169     {
6170       constructor_unfilled_fields
6171         = TREE_CHAIN (constructor_unfilled_fields);
6172
6173       /* Skip any nameless bit fields.  */
6174       while (constructor_unfilled_fields != 0
6175              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6176              && DECL_NAME (constructor_unfilled_fields) == 0)
6177         constructor_unfilled_fields =
6178           TREE_CHAIN (constructor_unfilled_fields);
6179     }
6180   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6181     constructor_unfilled_fields = 0;
6182
6183   /* Now output any pending elements which have become next.  */
6184   if (pending)
6185     output_pending_init_elements (0);
6186 }
6187
6188 /* Output any pending elements which have become next.
6189    As we output elements, constructor_unfilled_{fields,index}
6190    advances, which may cause other elements to become next;
6191    if so, they too are output.
6192
6193    If ALL is 0, we return when there are
6194    no more pending elements to output now.
6195
6196    If ALL is 1, we output space as necessary so that
6197    we can output all the pending elements.  */
6198
6199 static void
6200 output_pending_init_elements (int all)
6201 {
6202   struct init_node *elt = constructor_pending_elts;
6203   tree next;
6204
6205  retry:
6206
6207   /* Look through the whole pending tree.
6208      If we find an element that should be output now,
6209      output it.  Otherwise, set NEXT to the element
6210      that comes first among those still pending.  */
6211
6212   next = 0;
6213   while (elt)
6214     {
6215       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6216         {
6217           if (tree_int_cst_equal (elt->purpose,
6218                                   constructor_unfilled_index))
6219             output_init_element (elt->value, true,
6220                                  TREE_TYPE (constructor_type),
6221                                  constructor_unfilled_index, 0);
6222           else if (tree_int_cst_lt (constructor_unfilled_index,
6223                                     elt->purpose))
6224             {
6225               /* Advance to the next smaller node.  */
6226               if (elt->left)
6227                 elt = elt->left;
6228               else
6229                 {
6230                   /* We have reached the smallest node bigger than the
6231                      current unfilled index.  Fill the space first.  */
6232                   next = elt->purpose;
6233                   break;
6234                 }
6235             }
6236           else
6237             {
6238               /* Advance to the next bigger node.  */
6239               if (elt->right)
6240                 elt = elt->right;
6241               else
6242                 {
6243                   /* We have reached the biggest node in a subtree.  Find
6244                      the parent of it, which is the next bigger node.  */
6245                   while (elt->parent && elt->parent->right == elt)
6246                     elt = elt->parent;
6247                   elt = elt->parent;
6248                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6249                                               elt->purpose))
6250                     {
6251                       next = elt->purpose;
6252                       break;
6253                     }
6254                 }
6255             }
6256         }
6257       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6258                || TREE_CODE (constructor_type) == UNION_TYPE)
6259         {
6260           tree ctor_unfilled_bitpos, elt_bitpos;
6261
6262           /* If the current record is complete we are done.  */
6263           if (constructor_unfilled_fields == 0)
6264             break;
6265
6266           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6267           elt_bitpos = bit_position (elt->purpose);
6268           /* We can't compare fields here because there might be empty
6269              fields in between.  */
6270           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6271             {
6272               constructor_unfilled_fields = elt->purpose;
6273               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6274                                    elt->purpose, 0);
6275             }
6276           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6277             {
6278               /* Advance to the next smaller node.  */
6279               if (elt->left)
6280                 elt = elt->left;
6281               else
6282                 {
6283                   /* We have reached the smallest node bigger than the
6284                      current unfilled field.  Fill the space first.  */
6285                   next = elt->purpose;
6286                   break;
6287                 }
6288             }
6289           else
6290             {
6291               /* Advance to the next bigger node.  */
6292               if (elt->right)
6293                 elt = elt->right;
6294               else
6295                 {
6296                   /* We have reached the biggest node in a subtree.  Find
6297                      the parent of it, which is the next bigger node.  */
6298                   while (elt->parent && elt->parent->right == elt)
6299                     elt = elt->parent;
6300                   elt = elt->parent;
6301                   if (elt
6302                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6303                                            bit_position (elt->purpose))))
6304                     {
6305                       next = elt->purpose;
6306                       break;
6307                     }
6308                 }
6309             }
6310         }
6311     }
6312
6313   /* Ordinarily return, but not if we want to output all
6314      and there are elements left.  */
6315   if (!(all && next != 0))
6316     return;
6317
6318   /* If it's not incremental, just skip over the gap, so that after
6319      jumping to retry we will output the next successive element.  */
6320   if (TREE_CODE (constructor_type) == RECORD_TYPE
6321       || TREE_CODE (constructor_type) == UNION_TYPE)
6322     constructor_unfilled_fields = next;
6323   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6324     constructor_unfilled_index = next;
6325
6326   /* ELT now points to the node in the pending tree with the next
6327      initializer to output.  */
6328   goto retry;
6329 }
6330 \f
6331 /* Add one non-braced element to the current constructor level.
6332    This adjusts the current position within the constructor's type.
6333    This may also start or terminate implicit levels
6334    to handle a partly-braced initializer.
6335
6336    Once this has found the correct level for the new element,
6337    it calls output_init_element.  */
6338
6339 void
6340 process_init_element (struct c_expr value)
6341 {
6342   tree orig_value = value.value;
6343   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6344   bool strict_string = value.original_code == STRING_CST;
6345
6346   designator_depth = 0;
6347   designator_erroneous = 0;
6348
6349   /* Handle superfluous braces around string cst as in
6350      char x[] = {"foo"}; */
6351   if (string_flag
6352       && constructor_type
6353       && TREE_CODE (constructor_type) == ARRAY_TYPE
6354       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6355       && integer_zerop (constructor_unfilled_index))
6356     {
6357       if (constructor_stack->replacement_value.value)
6358         error_init ("excess elements in char array initializer");
6359       constructor_stack->replacement_value = value;
6360       return;
6361     }
6362
6363   if (constructor_stack->replacement_value.value != 0)
6364     {
6365       error_init ("excess elements in struct initializer");
6366       return;
6367     }
6368
6369   /* Ignore elements of a brace group if it is entirely superfluous
6370      and has already been diagnosed.  */
6371   if (constructor_type == 0)
6372     return;
6373
6374   /* If we've exhausted any levels that didn't have braces,
6375      pop them now.  */
6376   while (constructor_stack->implicit)
6377     {
6378       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6379            || TREE_CODE (constructor_type) == UNION_TYPE)
6380           && constructor_fields == 0)
6381         process_init_element (pop_init_level (1));
6382       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6383                && (constructor_max_index == 0
6384                    || tree_int_cst_lt (constructor_max_index,
6385                                        constructor_index)))
6386         process_init_element (pop_init_level (1));
6387       else
6388         break;
6389     }
6390
6391   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6392   if (constructor_range_stack)
6393     {
6394       /* If value is a compound literal and we'll be just using its
6395          content, don't put it into a SAVE_EXPR.  */
6396       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6397           || !require_constant_value
6398           || flag_isoc99)
6399         value.value = save_expr (value.value);
6400     }
6401
6402   while (1)
6403     {
6404       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6405         {
6406           tree fieldtype;
6407           enum tree_code fieldcode;
6408
6409           if (constructor_fields == 0)
6410             {
6411               pedwarn_init ("excess elements in struct initializer");
6412               break;
6413             }
6414
6415           fieldtype = TREE_TYPE (constructor_fields);
6416           if (fieldtype != error_mark_node)
6417             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6418           fieldcode = TREE_CODE (fieldtype);
6419
6420           /* Error for non-static initialization of a flexible array member.  */
6421           if (fieldcode == ARRAY_TYPE
6422               && !require_constant_value
6423               && TYPE_SIZE (fieldtype) == NULL_TREE
6424               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6425             {
6426               error_init ("non-static initialization of a flexible array member");
6427               break;
6428             }
6429
6430           /* Accept a string constant to initialize a subarray.  */
6431           if (value.value != 0
6432               && fieldcode == ARRAY_TYPE
6433               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6434               && string_flag)
6435             value.value = orig_value;
6436           /* Otherwise, if we have come to a subaggregate,
6437              and we don't have an element of its type, push into it.  */
6438           else if (value.value != 0
6439                    && value.value != error_mark_node
6440                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6441                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6442                        || fieldcode == UNION_TYPE))
6443             {
6444               push_init_level (1);
6445               continue;
6446             }
6447
6448           if (value.value)
6449             {
6450               push_member_name (constructor_fields);
6451               output_init_element (value.value, strict_string,
6452                                    fieldtype, constructor_fields, 1);
6453               RESTORE_SPELLING_DEPTH (constructor_depth);
6454             }
6455           else
6456             /* Do the bookkeeping for an element that was
6457                directly output as a constructor.  */
6458             {
6459               /* For a record, keep track of end position of last field.  */
6460               if (DECL_SIZE (constructor_fields))
6461                 constructor_bit_index
6462                   = size_binop (PLUS_EXPR,
6463                                 bit_position (constructor_fields),
6464                                 DECL_SIZE (constructor_fields));
6465
6466               /* If the current field was the first one not yet written out,
6467                  it isn't now, so update.  */
6468               if (constructor_unfilled_fields == constructor_fields)
6469                 {
6470                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6471                   /* Skip any nameless bit fields.  */
6472                   while (constructor_unfilled_fields != 0
6473                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6474                          && DECL_NAME (constructor_unfilled_fields) == 0)
6475                     constructor_unfilled_fields =
6476                       TREE_CHAIN (constructor_unfilled_fields);
6477                 }
6478             }
6479
6480           constructor_fields = TREE_CHAIN (constructor_fields);
6481           /* Skip any nameless bit fields at the beginning.  */
6482           while (constructor_fields != 0
6483                  && DECL_C_BIT_FIELD (constructor_fields)
6484                  && DECL_NAME (constructor_fields) == 0)
6485             constructor_fields = TREE_CHAIN (constructor_fields);
6486         }
6487       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6488         {
6489           tree fieldtype;
6490           enum tree_code fieldcode;
6491
6492           if (constructor_fields == 0)
6493             {
6494               pedwarn_init ("excess elements in union initializer");
6495               break;
6496             }
6497
6498           fieldtype = TREE_TYPE (constructor_fields);
6499           if (fieldtype != error_mark_node)
6500             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6501           fieldcode = TREE_CODE (fieldtype);
6502
6503           /* Warn that traditional C rejects initialization of unions.
6504              We skip the warning if the value is zero.  This is done
6505              under the assumption that the zero initializer in user
6506              code appears conditioned on e.g. __STDC__ to avoid
6507              "missing initializer" warnings and relies on default
6508              initialization to zero in the traditional C case.
6509              We also skip the warning if the initializer is designated,
6510              again on the assumption that this must be conditional on
6511              __STDC__ anyway (and we've already complained about the
6512              member-designator already).  */
6513           if (!in_system_header && !constructor_designated
6514               && !(value.value && (integer_zerop (value.value)
6515                                    || real_zerop (value.value))))
6516             warning (OPT_Wtraditional, "traditional C rejects initialization "
6517                      "of unions");
6518
6519           /* Accept a string constant to initialize a subarray.  */
6520           if (value.value != 0
6521               && fieldcode == ARRAY_TYPE
6522               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6523               && string_flag)
6524             value.value = orig_value;
6525           /* Otherwise, if we have come to a subaggregate,
6526              and we don't have an element of its type, push into it.  */
6527           else if (value.value != 0
6528                    && value.value != error_mark_node
6529                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6530                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6531                        || fieldcode == UNION_TYPE))
6532             {
6533               push_init_level (1);
6534               continue;
6535             }
6536
6537           if (value.value)
6538             {
6539               push_member_name (constructor_fields);
6540               output_init_element (value.value, strict_string,
6541                                    fieldtype, constructor_fields, 1);
6542               RESTORE_SPELLING_DEPTH (constructor_depth);
6543             }
6544           else
6545             /* Do the bookkeeping for an element that was
6546                directly output as a constructor.  */
6547             {
6548               constructor_bit_index = DECL_SIZE (constructor_fields);
6549               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6550             }
6551
6552           constructor_fields = 0;
6553         }
6554       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6555         {
6556           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6557           enum tree_code eltcode = TREE_CODE (elttype);
6558
6559           /* Accept a string constant to initialize a subarray.  */
6560           if (value.value != 0
6561               && eltcode == ARRAY_TYPE
6562               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6563               && string_flag)
6564             value.value = orig_value;
6565           /* Otherwise, if we have come to a subaggregate,
6566              and we don't have an element of its type, push into it.  */
6567           else if (value.value != 0
6568                    && value.value != error_mark_node
6569                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6570                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6571                        || eltcode == UNION_TYPE))
6572             {
6573               push_init_level (1);
6574               continue;
6575             }
6576
6577           if (constructor_max_index != 0
6578               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6579                   || integer_all_onesp (constructor_max_index)))
6580             {
6581               pedwarn_init ("excess elements in array initializer");
6582               break;
6583             }
6584
6585           /* Now output the actual element.  */
6586           if (value.value)
6587             {
6588               push_array_bounds (tree_low_cst (constructor_index, 1));
6589               output_init_element (value.value, strict_string,
6590                                    elttype, constructor_index, 1);
6591               RESTORE_SPELLING_DEPTH (constructor_depth);
6592             }
6593
6594           constructor_index
6595             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6596
6597           if (!value.value)
6598             /* If we are doing the bookkeeping for an element that was
6599                directly output as a constructor, we must update
6600                constructor_unfilled_index.  */
6601             constructor_unfilled_index = constructor_index;
6602         }
6603       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6604         {
6605           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6606
6607          /* Do a basic check of initializer size.  Note that vectors
6608             always have a fixed size derived from their type.  */
6609           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6610             {
6611               pedwarn_init ("excess elements in vector initializer");
6612               break;
6613             }
6614
6615           /* Now output the actual element.  */
6616           if (value.value)
6617             output_init_element (value.value, strict_string,
6618                                  elttype, constructor_index, 1);
6619
6620           constructor_index
6621             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6622
6623           if (!value.value)
6624             /* If we are doing the bookkeeping for an element that was
6625                directly output as a constructor, we must update
6626                constructor_unfilled_index.  */
6627             constructor_unfilled_index = constructor_index;
6628         }
6629
6630       /* Handle the sole element allowed in a braced initializer
6631          for a scalar variable.  */
6632       else if (constructor_type != error_mark_node
6633                && constructor_fields == 0)
6634         {
6635           pedwarn_init ("excess elements in scalar initializer");
6636           break;
6637         }
6638       else
6639         {
6640           if (value.value)
6641             output_init_element (value.value, strict_string,
6642                                  constructor_type, NULL_TREE, 1);
6643           constructor_fields = 0;
6644         }
6645
6646       /* Handle range initializers either at this level or anywhere higher
6647          in the designator stack.  */
6648       if (constructor_range_stack)
6649         {
6650           struct constructor_range_stack *p, *range_stack;
6651           int finish = 0;
6652
6653           range_stack = constructor_range_stack;
6654           constructor_range_stack = 0;
6655           while (constructor_stack != range_stack->stack)
6656             {
6657               gcc_assert (constructor_stack->implicit);
6658               process_init_element (pop_init_level (1));
6659             }
6660           for (p = range_stack;
6661                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6662                p = p->prev)
6663             {
6664               gcc_assert (constructor_stack->implicit);
6665               process_init_element (pop_init_level (1));
6666             }
6667
6668           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6669           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6670             finish = 1;
6671
6672           while (1)
6673             {
6674               constructor_index = p->index;
6675               constructor_fields = p->fields;
6676               if (finish && p->range_end && p->index == p->range_start)
6677                 {
6678                   finish = 0;
6679                   p->prev = 0;
6680                 }
6681               p = p->next;
6682               if (!p)
6683                 break;
6684               push_init_level (2);
6685               p->stack = constructor_stack;
6686               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6687                 p->index = p->range_start;
6688             }
6689
6690           if (!finish)
6691             constructor_range_stack = range_stack;
6692           continue;
6693         }
6694
6695       break;
6696     }
6697
6698   constructor_range_stack = 0;
6699 }
6700 \f
6701 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6702    (guaranteed to be 'volatile' or null) and ARGS (represented using
6703    an ASM_EXPR node).  */
6704 tree
6705 build_asm_stmt (tree cv_qualifier, tree args)
6706 {
6707   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6708     ASM_VOLATILE_P (args) = 1;
6709   return add_stmt (args);
6710 }
6711
6712 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6713    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6714    SIMPLE indicates whether there was anything at all after the
6715    string in the asm expression -- asm("blah") and asm("blah" : )
6716    are subtly different.  We use a ASM_EXPR node to represent this.  */
6717 tree
6718 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6719                 bool simple)
6720 {
6721   tree tail;
6722   tree args;
6723   int i;
6724   const char *constraint;
6725   const char **oconstraints;
6726   bool allows_mem, allows_reg, is_inout;
6727   int ninputs, noutputs;
6728
6729   ninputs = list_length (inputs);
6730   noutputs = list_length (outputs);
6731   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6732
6733   string = resolve_asm_operand_names (string, outputs, inputs);
6734
6735   /* Remove output conversions that change the type but not the mode.  */
6736   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6737     {
6738       tree output = TREE_VALUE (tail);
6739
6740       /* ??? Really, this should not be here.  Users should be using a
6741          proper lvalue, dammit.  But there's a long history of using casts
6742          in the output operands.  In cases like longlong.h, this becomes a
6743          primitive form of typechecking -- if the cast can be removed, then
6744          the output operand had a type of the proper width; otherwise we'll
6745          get an error.  Gross, but ...  */
6746       STRIP_NOPS (output);
6747
6748       if (!lvalue_or_else (output, lv_asm))
6749         output = error_mark_node;
6750
6751       if (output != error_mark_node
6752           && (TREE_READONLY (output)
6753               || TYPE_READONLY (TREE_TYPE (output))
6754               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6755                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6756                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6757         readonly_error (output, lv_asm);
6758
6759       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6760       oconstraints[i] = constraint;
6761
6762       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6763                                    &allows_mem, &allows_reg, &is_inout))
6764         {
6765           /* If the operand is going to end up in memory,
6766              mark it addressable.  */
6767           if (!allows_reg && !c_mark_addressable (output))
6768             output = error_mark_node;
6769         }
6770       else
6771         output = error_mark_node;
6772
6773       TREE_VALUE (tail) = output;
6774     }
6775
6776   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6777     {
6778       tree input;
6779
6780       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6781       input = TREE_VALUE (tail);
6782
6783       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6784                                   oconstraints, &allows_mem, &allows_reg))
6785         {
6786           /* If the operand is going to end up in memory,
6787              mark it addressable.  */
6788           if (!allows_reg && allows_mem)
6789             {
6790               /* Strip the nops as we allow this case.  FIXME, this really
6791                  should be rejected or made deprecated.  */
6792               STRIP_NOPS (input);
6793               if (!c_mark_addressable (input))
6794                 input = error_mark_node;
6795           }
6796         }
6797       else
6798         input = error_mark_node;
6799
6800       TREE_VALUE (tail) = input;
6801     }
6802
6803   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6804
6805   /* asm statements without outputs, including simple ones, are treated
6806      as volatile.  */
6807   ASM_INPUT_P (args) = simple;
6808   ASM_VOLATILE_P (args) = (noutputs == 0);
6809
6810   return args;
6811 }
6812 \f
6813 /* Generate a goto statement to LABEL.  */
6814
6815 tree
6816 c_finish_goto_label (tree label)
6817 {
6818   tree decl = lookup_label (label);
6819   if (!decl)
6820     return NULL_TREE;
6821
6822   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6823     {
6824       error ("jump into statement expression");
6825       return NULL_TREE;
6826     }
6827
6828   if (C_DECL_UNJUMPABLE_VM (decl))
6829     {
6830       error ("jump into scope of identifier with variably modified type");
6831       return NULL_TREE;
6832     }
6833
6834   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6835     {
6836       /* No jump from outside this statement expression context, so
6837          record that there is a jump from within this context.  */
6838       struct c_label_list *nlist;
6839       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6840       nlist->next = label_context_stack_se->labels_used;
6841       nlist->label = decl;
6842       label_context_stack_se->labels_used = nlist;
6843     }
6844
6845   if (!C_DECL_UNDEFINABLE_VM (decl))
6846     {
6847       /* No jump from outside this context context of identifiers with
6848          variably modified type, so record that there is a jump from
6849          within this context.  */
6850       struct c_label_list *nlist;
6851       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6852       nlist->next = label_context_stack_vm->labels_used;
6853       nlist->label = decl;
6854       label_context_stack_vm->labels_used = nlist;
6855     }
6856
6857   TREE_USED (decl) = 1;
6858   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6859 }
6860
6861 /* Generate a computed goto statement to EXPR.  */
6862
6863 tree
6864 c_finish_goto_ptr (tree expr)
6865 {
6866   if (pedantic)
6867     pedwarn ("ISO C forbids %<goto *expr;%>");
6868   expr = convert (ptr_type_node, expr);
6869   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6870 }
6871
6872 /* Generate a C `return' statement.  RETVAL is the expression for what
6873    to return, or a null pointer for `return;' with no value.  */
6874
6875 tree
6876 c_finish_return (tree retval)
6877 {
6878   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6879   bool no_warning = false;
6880
6881   if (TREE_THIS_VOLATILE (current_function_decl))
6882     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6883
6884   if (!retval)
6885     {
6886       current_function_returns_null = 1;
6887       if ((warn_return_type || flag_isoc99)
6888           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6889         {
6890           pedwarn_c99 ("%<return%> with no value, in "
6891                        "function returning non-void");
6892           no_warning = true;
6893         }
6894     }
6895   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6896     {
6897       current_function_returns_null = 1;
6898       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6899         pedwarn ("%<return%> with a value, in function returning void");
6900     }
6901   else
6902     {
6903       tree t = convert_for_assignment (valtype, retval, ic_return,
6904                                        NULL_TREE, NULL_TREE, 0);
6905       tree res = DECL_RESULT (current_function_decl);
6906       tree inner;
6907
6908       current_function_returns_value = 1;
6909       if (t == error_mark_node)
6910         return NULL_TREE;
6911
6912       inner = t = convert (TREE_TYPE (res), t);
6913
6914       /* Strip any conversions, additions, and subtractions, and see if
6915          we are returning the address of a local variable.  Warn if so.  */
6916       while (1)
6917         {
6918           switch (TREE_CODE (inner))
6919             {
6920             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6921             case PLUS_EXPR:
6922               inner = TREE_OPERAND (inner, 0);
6923               continue;
6924
6925             case MINUS_EXPR:
6926               /* If the second operand of the MINUS_EXPR has a pointer
6927                  type (or is converted from it), this may be valid, so
6928                  don't give a warning.  */
6929               {
6930                 tree op1 = TREE_OPERAND (inner, 1);
6931
6932                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6933                        && (TREE_CODE (op1) == NOP_EXPR
6934                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6935                            || TREE_CODE (op1) == CONVERT_EXPR))
6936                   op1 = TREE_OPERAND (op1, 0);
6937
6938                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6939                   break;
6940
6941                 inner = TREE_OPERAND (inner, 0);
6942                 continue;
6943               }
6944
6945             case ADDR_EXPR:
6946               inner = TREE_OPERAND (inner, 0);
6947
6948               while (REFERENCE_CLASS_P (inner)
6949                      && TREE_CODE (inner) != INDIRECT_REF)
6950                 inner = TREE_OPERAND (inner, 0);
6951
6952               if (DECL_P (inner)
6953                   && !DECL_EXTERNAL (inner)
6954                   && !TREE_STATIC (inner)
6955                   && DECL_CONTEXT (inner) == current_function_decl)
6956                 warning (0, "function returns address of local variable");
6957               break;
6958
6959             default:
6960               break;
6961             }
6962
6963           break;
6964         }
6965
6966       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6967     }
6968
6969   ret_stmt = build_stmt (RETURN_EXPR, retval);
6970   TREE_NO_WARNING (ret_stmt) |= no_warning;
6971   return add_stmt (ret_stmt);
6972 }
6973 \f
6974 struct c_switch {
6975   /* The SWITCH_EXPR being built.  */
6976   tree switch_expr;
6977
6978   /* The original type of the testing expression, i.e. before the
6979      default conversion is applied.  */
6980   tree orig_type;
6981
6982   /* A splay-tree mapping the low element of a case range to the high
6983      element, or NULL_TREE if there is no high element.  Used to
6984      determine whether or not a new case label duplicates an old case
6985      label.  We need a tree, rather than simply a hash table, because
6986      of the GNU case range extension.  */
6987   splay_tree cases;
6988
6989   /* Number of nested statement expressions within this switch
6990      statement; if nonzero, case and default labels may not
6991      appear.  */
6992   unsigned int blocked_stmt_expr;
6993
6994   /* Scope of outermost declarations of identifiers with variably
6995      modified type within this switch statement; if nonzero, case and
6996      default labels may not appear.  */
6997   unsigned int blocked_vm;
6998
6999   /* The next node on the stack.  */
7000   struct c_switch *next;
7001 };
7002
7003 /* A stack of the currently active switch statements.  The innermost
7004    switch statement is on the top of the stack.  There is no need to
7005    mark the stack for garbage collection because it is only active
7006    during the processing of the body of a function, and we never
7007    collect at that point.  */
7008
7009 struct c_switch *c_switch_stack;
7010
7011 /* Start a C switch statement, testing expression EXP.  Return the new
7012    SWITCH_EXPR.  */
7013
7014 tree
7015 c_start_case (tree exp)
7016 {
7017   enum tree_code code;
7018   tree type, orig_type = error_mark_node;
7019   struct c_switch *cs;
7020
7021   if (exp != error_mark_node)
7022     {
7023       code = TREE_CODE (TREE_TYPE (exp));
7024       orig_type = TREE_TYPE (exp);
7025
7026       if (!INTEGRAL_TYPE_P (orig_type)
7027           && code != ERROR_MARK)
7028         {
7029           error ("switch quantity not an integer");
7030           exp = integer_zero_node;
7031           orig_type = error_mark_node;
7032         }
7033       else
7034         {
7035           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
7036
7037           if (!in_system_header
7038               && (type == long_integer_type_node
7039                   || type == long_unsigned_type_node))
7040             warning (OPT_Wtraditional, "%<long%> switch expression not "
7041                      "converted to %<int%> in ISO C");
7042
7043           exp = default_conversion (exp);
7044           type = TREE_TYPE (exp);
7045         }
7046     }
7047
7048   /* Add this new SWITCH_EXPR to the stack.  */
7049   cs = XNEW (struct c_switch);
7050   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7051   cs->orig_type = orig_type;
7052   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7053   cs->blocked_stmt_expr = 0;
7054   cs->blocked_vm = 0;
7055   cs->next = c_switch_stack;
7056   c_switch_stack = cs;
7057
7058   return add_stmt (cs->switch_expr);
7059 }
7060
7061 /* Process a case label.  */
7062
7063 tree
7064 do_case (tree low_value, tree high_value)
7065 {
7066   tree label = NULL_TREE;
7067
7068   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7069       && !c_switch_stack->blocked_vm)
7070     {
7071       label = c_add_case_label (c_switch_stack->cases,
7072                                 SWITCH_COND (c_switch_stack->switch_expr),
7073                                 c_switch_stack->orig_type,
7074                                 low_value, high_value);
7075       if (label == error_mark_node)
7076         label = NULL_TREE;
7077     }
7078   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7079     {
7080       if (low_value)
7081         error ("case label in statement expression not containing "
7082                "enclosing switch statement");
7083       else
7084         error ("%<default%> label in statement expression not containing "
7085                "enclosing switch statement");
7086     }
7087   else if (c_switch_stack && c_switch_stack->blocked_vm)
7088     {
7089       if (low_value)
7090         error ("case label in scope of identifier with variably modified "
7091                "type not containing enclosing switch statement");
7092       else
7093         error ("%<default%> label in scope of identifier with variably "
7094                "modified type not containing enclosing switch statement");
7095     }
7096   else if (low_value)
7097     error ("case label not within a switch statement");
7098   else
7099     error ("%<default%> label not within a switch statement");
7100
7101   return label;
7102 }
7103
7104 /* Finish the switch statement.  */
7105
7106 void
7107 c_finish_case (tree body)
7108 {
7109   struct c_switch *cs = c_switch_stack;
7110   location_t switch_location;
7111
7112   SWITCH_BODY (cs->switch_expr) = body;
7113
7114   /* We must not be within a statement expression nested in the switch
7115      at this point; we might, however, be within the scope of an
7116      identifier with variably modified type nested in the switch.  */
7117   gcc_assert (!cs->blocked_stmt_expr);
7118
7119   /* Emit warnings as needed.  */
7120   if (EXPR_HAS_LOCATION (cs->switch_expr))
7121     switch_location = EXPR_LOCATION (cs->switch_expr);
7122   else
7123     switch_location = input_location;
7124   c_do_switch_warnings (cs->cases, switch_location,
7125                         TREE_TYPE (cs->switch_expr),
7126                         SWITCH_COND (cs->switch_expr));
7127
7128   /* Pop the stack.  */
7129   c_switch_stack = cs->next;
7130   splay_tree_delete (cs->cases);
7131   XDELETE (cs);
7132 }
7133 \f
7134 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7135    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7136    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7137    statement, and was not surrounded with parenthesis.  */
7138
7139 void
7140 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7141                   tree else_block, bool nested_if)
7142 {
7143   tree stmt;
7144
7145   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7146   if (warn_parentheses && nested_if && else_block == NULL)
7147     {
7148       tree inner_if = then_block;
7149
7150       /* We know from the grammar productions that there is an IF nested
7151          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7152          it might not be exactly THEN_BLOCK, but should be the last
7153          non-container statement within.  */
7154       while (1)
7155         switch (TREE_CODE (inner_if))
7156           {
7157           case COND_EXPR:
7158             goto found;
7159           case BIND_EXPR:
7160             inner_if = BIND_EXPR_BODY (inner_if);
7161             break;
7162           case STATEMENT_LIST:
7163             inner_if = expr_last (then_block);
7164             break;
7165           case TRY_FINALLY_EXPR:
7166           case TRY_CATCH_EXPR:
7167             inner_if = TREE_OPERAND (inner_if, 0);
7168             break;
7169           default:
7170             gcc_unreachable ();
7171           }
7172     found:
7173
7174       if (COND_EXPR_ELSE (inner_if))
7175          warning (OPT_Wparentheses,
7176                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7177                   &if_locus);
7178     }
7179
7180   empty_body_warning (then_block, else_block);
7181
7182   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7183   SET_EXPR_LOCATION (stmt, if_locus);
7184   add_stmt (stmt);
7185 }
7186
7187 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7188    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7189    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7190    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7191    the continue label.  Everything is allowed to be NULL.  */
7192
7193 void
7194 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7195                tree blab, tree clab, bool cond_is_first)
7196 {
7197   tree entry = NULL, exit = NULL, t;
7198
7199   /* If the condition is zero don't generate a loop construct.  */
7200   if (cond && integer_zerop (cond))
7201     {
7202       if (cond_is_first)
7203         {
7204           t = build_and_jump (&blab);
7205           SET_EXPR_LOCATION (t, start_locus);
7206           add_stmt (t);
7207         }
7208     }
7209   else
7210     {
7211       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7212
7213       /* If we have an exit condition, then we build an IF with gotos either
7214          out of the loop, or to the top of it.  If there's no exit condition,
7215          then we just build a jump back to the top.  */
7216       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7217
7218       if (cond && !integer_nonzerop (cond))
7219         {
7220           /* Canonicalize the loop condition to the end.  This means
7221              generating a branch to the loop condition.  Reuse the
7222              continue label, if possible.  */
7223           if (cond_is_first)
7224             {
7225               if (incr || !clab)
7226                 {
7227                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7228                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7229                 }
7230               else
7231                 t = build1 (GOTO_EXPR, void_type_node, clab);
7232               SET_EXPR_LOCATION (t, start_locus);
7233               add_stmt (t);
7234             }
7235
7236           t = build_and_jump (&blab);
7237           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7238           if (cond_is_first)
7239             SET_EXPR_LOCATION (exit, start_locus);
7240           else
7241             SET_EXPR_LOCATION (exit, input_location);
7242         }
7243
7244       add_stmt (top);
7245     }
7246
7247   if (body)
7248     add_stmt (body);
7249   if (clab)
7250     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7251   if (incr)
7252     add_stmt (incr);
7253   if (entry)
7254     add_stmt (entry);
7255   if (exit)
7256     add_stmt (exit);
7257   if (blab)
7258     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7259 }
7260
7261 tree
7262 c_finish_bc_stmt (tree *label_p, bool is_break)
7263 {
7264   bool skip;
7265   tree label = *label_p;
7266
7267   /* In switch statements break is sometimes stylistically used after
7268      a return statement.  This can lead to spurious warnings about
7269      control reaching the end of a non-void function when it is
7270      inlined.  Note that we are calling block_may_fallthru with
7271      language specific tree nodes; this works because
7272      block_may_fallthru returns true when given something it does not
7273      understand.  */
7274   skip = !block_may_fallthru (cur_stmt_list);
7275
7276   if (!label)
7277     {
7278       if (!skip)
7279         *label_p = label = create_artificial_label ();
7280     }
7281   else if (TREE_CODE (label) == LABEL_DECL)
7282     ;
7283   else switch (TREE_INT_CST_LOW (label))
7284     {
7285     case 0:
7286       if (is_break)
7287         error ("break statement not within loop or switch");
7288       else
7289         error ("continue statement not within a loop");
7290       return NULL_TREE;
7291
7292     case 1:
7293       gcc_assert (is_break);
7294       error ("break statement used with OpenMP for loop");
7295       return NULL_TREE;
7296
7297     default:
7298       gcc_unreachable ();
7299     }
7300
7301   if (skip)
7302     return NULL_TREE;
7303
7304   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7305 }
7306
7307 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7308
7309 static void
7310 emit_side_effect_warnings (tree expr)
7311 {
7312   if (expr == error_mark_node)
7313     ;
7314   else if (!TREE_SIDE_EFFECTS (expr))
7315     {
7316       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7317         warning (0, "%Hstatement with no effect",
7318                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7319     }
7320   else if (warn_unused_value)
7321     warn_if_unused_value (expr, input_location);
7322 }
7323
7324 /* Process an expression as if it were a complete statement.  Emit
7325    diagnostics, but do not call ADD_STMT.  */
7326
7327 tree
7328 c_process_expr_stmt (tree expr)
7329 {
7330   if (!expr)
7331     return NULL_TREE;
7332
7333   if (warn_sequence_point)
7334     verify_sequence_points (expr);
7335
7336   if (TREE_TYPE (expr) != error_mark_node
7337       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7338       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7339     error ("expression statement has incomplete type");
7340
7341   /* If we're not processing a statement expression, warn about unused values.
7342      Warnings for statement expressions will be emitted later, once we figure
7343      out which is the result.  */
7344   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7345       && (extra_warnings || warn_unused_value))
7346     emit_side_effect_warnings (expr);
7347
7348   /* If the expression is not of a type to which we cannot assign a line
7349      number, wrap the thing in a no-op NOP_EXPR.  */
7350   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7351     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7352
7353   if (EXPR_P (expr))
7354     SET_EXPR_LOCATION (expr, input_location);
7355
7356   return expr;
7357 }
7358
7359 /* Emit an expression as a statement.  */
7360
7361 tree
7362 c_finish_expr_stmt (tree expr)
7363 {
7364   if (expr)
7365     return add_stmt (c_process_expr_stmt (expr));
7366   else
7367     return NULL;
7368 }
7369
7370 /* Do the opposite and emit a statement as an expression.  To begin,
7371    create a new binding level and return it.  */
7372
7373 tree
7374 c_begin_stmt_expr (void)
7375 {
7376   tree ret;
7377   struct c_label_context_se *nstack;
7378   struct c_label_list *glist;
7379
7380   /* We must force a BLOCK for this level so that, if it is not expanded
7381      later, there is a way to turn off the entire subtree of blocks that
7382      are contained in it.  */
7383   keep_next_level ();
7384   ret = c_begin_compound_stmt (true);
7385   if (c_switch_stack)
7386     {
7387       c_switch_stack->blocked_stmt_expr++;
7388       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7389     }
7390   for (glist = label_context_stack_se->labels_used;
7391        glist != NULL;
7392        glist = glist->next)
7393     {
7394       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7395     }
7396   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7397   nstack->labels_def = NULL;
7398   nstack->labels_used = NULL;
7399   nstack->next = label_context_stack_se;
7400   label_context_stack_se = nstack;
7401
7402   /* Mark the current statement list as belonging to a statement list.  */
7403   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7404
7405   return ret;
7406 }
7407
7408 tree
7409 c_finish_stmt_expr (tree body)
7410 {
7411   tree last, type, tmp, val;
7412   tree *last_p;
7413   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7414
7415   body = c_end_compound_stmt (body, true);
7416   if (c_switch_stack)
7417     {
7418       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7419       c_switch_stack->blocked_stmt_expr--;
7420     }
7421   /* It is no longer possible to jump to labels defined within this
7422      statement expression.  */
7423   for (dlist = label_context_stack_se->labels_def;
7424        dlist != NULL;
7425        dlist = dlist->next)
7426     {
7427       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7428     }
7429   /* It is again possible to define labels with a goto just outside
7430      this statement expression.  */
7431   for (glist = label_context_stack_se->next->labels_used;
7432        glist != NULL;
7433        glist = glist->next)
7434     {
7435       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7436       glist_prev = glist;
7437     }
7438   if (glist_prev != NULL)
7439     glist_prev->next = label_context_stack_se->labels_used;
7440   else
7441     label_context_stack_se->next->labels_used
7442       = label_context_stack_se->labels_used;
7443   label_context_stack_se = label_context_stack_se->next;
7444
7445   /* Locate the last statement in BODY.  See c_end_compound_stmt
7446      about always returning a BIND_EXPR.  */
7447   last_p = &BIND_EXPR_BODY (body);
7448   last = BIND_EXPR_BODY (body);
7449
7450  continue_searching:
7451   if (TREE_CODE (last) == STATEMENT_LIST)
7452     {
7453       tree_stmt_iterator i;
7454
7455       /* This can happen with degenerate cases like ({ }).  No value.  */
7456       if (!TREE_SIDE_EFFECTS (last))
7457         return body;
7458
7459       /* If we're supposed to generate side effects warnings, process
7460          all of the statements except the last.  */
7461       if (extra_warnings || warn_unused_value)
7462         {
7463           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7464             emit_side_effect_warnings (tsi_stmt (i));
7465         }
7466       else
7467         i = tsi_last (last);
7468       last_p = tsi_stmt_ptr (i);
7469       last = *last_p;
7470     }
7471
7472   /* If the end of the list is exception related, then the list was split
7473      by a call to push_cleanup.  Continue searching.  */
7474   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7475       || TREE_CODE (last) == TRY_CATCH_EXPR)
7476     {
7477       last_p = &TREE_OPERAND (last, 0);
7478       last = *last_p;
7479       goto continue_searching;
7480     }
7481
7482   /* In the case that the BIND_EXPR is not necessary, return the
7483      expression out from inside it.  */
7484   if (last == error_mark_node
7485       || (last == BIND_EXPR_BODY (body)
7486           && BIND_EXPR_VARS (body) == NULL))
7487     {
7488       /* Do not warn if the return value of a statement expression is
7489          unused.  */
7490       if (EXPR_P (last))
7491         TREE_NO_WARNING (last) = 1;
7492       return last;
7493     }
7494
7495   /* Extract the type of said expression.  */
7496   type = TREE_TYPE (last);
7497
7498   /* If we're not returning a value at all, then the BIND_EXPR that
7499      we already have is a fine expression to return.  */
7500   if (!type || VOID_TYPE_P (type))
7501     return body;
7502
7503   /* Now that we've located the expression containing the value, it seems
7504      silly to make voidify_wrapper_expr repeat the process.  Create a
7505      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7506   tmp = create_tmp_var_raw (type, NULL);
7507
7508   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7509      tree_expr_nonnegative_p giving up immediately.  */
7510   val = last;
7511   if (TREE_CODE (val) == NOP_EXPR
7512       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7513     val = TREE_OPERAND (val, 0);
7514
7515   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7516   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7517
7518   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7519 }
7520
7521 /* Begin the scope of an identifier of variably modified type, scope
7522    number SCOPE.  Jumping from outside this scope to inside it is not
7523    permitted.  */
7524
7525 void
7526 c_begin_vm_scope (unsigned int scope)
7527 {
7528   struct c_label_context_vm *nstack;
7529   struct c_label_list *glist;
7530
7531   gcc_assert (scope > 0);
7532   if (c_switch_stack && !c_switch_stack->blocked_vm)
7533     c_switch_stack->blocked_vm = scope;
7534   for (glist = label_context_stack_vm->labels_used;
7535        glist != NULL;
7536        glist = glist->next)
7537     {
7538       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7539     }
7540   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7541   nstack->labels_def = NULL;
7542   nstack->labels_used = NULL;
7543   nstack->scope = scope;
7544   nstack->next = label_context_stack_vm;
7545   label_context_stack_vm = nstack;
7546 }
7547
7548 /* End a scope which may contain identifiers of variably modified
7549    type, scope number SCOPE.  */
7550
7551 void
7552 c_end_vm_scope (unsigned int scope)
7553 {
7554   if (label_context_stack_vm == NULL)
7555     return;
7556   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7557     c_switch_stack->blocked_vm = 0;
7558   /* We may have a number of nested scopes of identifiers with
7559      variably modified type, all at this depth.  Pop each in turn.  */
7560   while (label_context_stack_vm->scope == scope)
7561     {
7562       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7563
7564       /* It is no longer possible to jump to labels defined within this
7565          scope.  */
7566       for (dlist = label_context_stack_vm->labels_def;
7567            dlist != NULL;
7568            dlist = dlist->next)
7569         {
7570           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7571         }
7572       /* It is again possible to define labels with a goto just outside
7573          this scope.  */
7574       for (glist = label_context_stack_vm->next->labels_used;
7575            glist != NULL;
7576            glist = glist->next)
7577         {
7578           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7579           glist_prev = glist;
7580         }
7581       if (glist_prev != NULL)
7582         glist_prev->next = label_context_stack_vm->labels_used;
7583       else
7584         label_context_stack_vm->next->labels_used
7585           = label_context_stack_vm->labels_used;
7586       label_context_stack_vm = label_context_stack_vm->next;
7587     }
7588 }
7589 \f
7590 /* Begin and end compound statements.  This is as simple as pushing
7591    and popping new statement lists from the tree.  */
7592
7593 tree
7594 c_begin_compound_stmt (bool do_scope)
7595 {
7596   tree stmt = push_stmt_list ();
7597   if (do_scope)
7598     push_scope ();
7599   return stmt;
7600 }
7601
7602 tree
7603 c_end_compound_stmt (tree stmt, bool do_scope)
7604 {
7605   tree block = NULL;
7606
7607   if (do_scope)
7608     {
7609       if (c_dialect_objc ())
7610         objc_clear_super_receiver ();
7611       block = pop_scope ();
7612     }
7613
7614   stmt = pop_stmt_list (stmt);
7615   stmt = c_build_bind_expr (block, stmt);
7616
7617   /* If this compound statement is nested immediately inside a statement
7618      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7619      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7620      STATEMENT_LISTs merge, and thus we can lose track of what statement
7621      was really last.  */
7622   if (cur_stmt_list
7623       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7624       && TREE_CODE (stmt) != BIND_EXPR)
7625     {
7626       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7627       TREE_SIDE_EFFECTS (stmt) = 1;
7628     }
7629
7630   return stmt;
7631 }
7632
7633 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7634    when the current scope is exited.  EH_ONLY is true when this is not
7635    meant to apply to normal control flow transfer.  */
7636
7637 void
7638 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7639 {
7640   enum tree_code code;
7641   tree stmt, list;
7642   bool stmt_expr;
7643
7644   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7645   stmt = build_stmt (code, NULL, cleanup);
7646   add_stmt (stmt);
7647   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7648   list = push_stmt_list ();
7649   TREE_OPERAND (stmt, 0) = list;
7650   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7651 }
7652 \f
7653 /* Build a binary-operation expression without default conversions.
7654    CODE is the kind of expression to build.
7655    This function differs from `build' in several ways:
7656    the data type of the result is computed and recorded in it,
7657    warnings are generated if arg data types are invalid,
7658    special handling for addition and subtraction of pointers is known,
7659    and some optimization is done (operations on narrow ints
7660    are done in the narrower type when that gives the same result).
7661    Constant folding is also done before the result is returned.
7662
7663    Note that the operands will never have enumeral types, or function
7664    or array types, because either they will have the default conversions
7665    performed or they have both just been converted to some other type in which
7666    the arithmetic is to be done.  */
7667
7668 tree
7669 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7670                  int convert_p)
7671 {
7672   tree type0, type1;
7673   enum tree_code code0, code1;
7674   tree op0, op1;
7675   const char *invalid_op_diag;
7676
7677   /* Expression code to give to the expression when it is built.
7678      Normally this is CODE, which is what the caller asked for,
7679      but in some special cases we change it.  */
7680   enum tree_code resultcode = code;
7681
7682   /* Data type in which the computation is to be performed.
7683      In the simplest cases this is the common type of the arguments.  */
7684   tree result_type = NULL;
7685
7686   /* Nonzero means operands have already been type-converted
7687      in whatever way is necessary.
7688      Zero means they need to be converted to RESULT_TYPE.  */
7689   int converted = 0;
7690
7691   /* Nonzero means create the expression with this type, rather than
7692      RESULT_TYPE.  */
7693   tree build_type = 0;
7694
7695   /* Nonzero means after finally constructing the expression
7696      convert it to this type.  */
7697   tree final_type = 0;
7698
7699   /* Nonzero if this is an operation like MIN or MAX which can
7700      safely be computed in short if both args are promoted shorts.
7701      Also implies COMMON.
7702      -1 indicates a bitwise operation; this makes a difference
7703      in the exact conditions for when it is safe to do the operation
7704      in a narrower mode.  */
7705   int shorten = 0;
7706
7707   /* Nonzero if this is a comparison operation;
7708      if both args are promoted shorts, compare the original shorts.
7709      Also implies COMMON.  */
7710   int short_compare = 0;
7711
7712   /* Nonzero if this is a right-shift operation, which can be computed on the
7713      original short and then promoted if the operand is a promoted short.  */
7714   int short_shift = 0;
7715
7716   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7717   int common = 0;
7718
7719   /* True means types are compatible as far as ObjC is concerned.  */
7720   bool objc_ok;
7721
7722   if (convert_p)
7723     {
7724       op0 = default_conversion (orig_op0);
7725       op1 = default_conversion (orig_op1);
7726     }
7727   else
7728     {
7729       op0 = orig_op0;
7730       op1 = orig_op1;
7731     }
7732
7733   type0 = TREE_TYPE (op0);
7734   type1 = TREE_TYPE (op1);
7735
7736   /* The expression codes of the data types of the arguments tell us
7737      whether the arguments are integers, floating, pointers, etc.  */
7738   code0 = TREE_CODE (type0);
7739   code1 = TREE_CODE (type1);
7740
7741   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7742   STRIP_TYPE_NOPS (op0);
7743   STRIP_TYPE_NOPS (op1);
7744
7745   /* If an error was already reported for one of the arguments,
7746      avoid reporting another error.  */
7747
7748   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7749     return error_mark_node;
7750
7751   if ((invalid_op_diag
7752        = targetm.invalid_binary_op (code, type0, type1)))
7753     {
7754       error (invalid_op_diag);
7755       return error_mark_node;
7756     }
7757
7758   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7759
7760   switch (code)
7761     {
7762     case PLUS_EXPR:
7763       /* Handle the pointer + int case.  */
7764       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7765         return pointer_int_sum (PLUS_EXPR, op0, op1);
7766       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7767         return pointer_int_sum (PLUS_EXPR, op1, op0);
7768       else
7769         common = 1;
7770       break;
7771
7772     case MINUS_EXPR:
7773       /* Subtraction of two similar pointers.
7774          We must subtract them as integers, then divide by object size.  */
7775       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7776           && comp_target_types (type0, type1))
7777         return pointer_diff (op0, op1);
7778       /* Handle pointer minus int.  Just like pointer plus int.  */
7779       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7780         return pointer_int_sum (MINUS_EXPR, op0, op1);
7781       else
7782         common = 1;
7783       break;
7784
7785     case MULT_EXPR:
7786       common = 1;
7787       break;
7788
7789     case TRUNC_DIV_EXPR:
7790     case CEIL_DIV_EXPR:
7791     case FLOOR_DIV_EXPR:
7792     case ROUND_DIV_EXPR:
7793     case EXACT_DIV_EXPR:
7794       /* Floating point division by zero is a legitimate way to obtain
7795          infinities and NaNs.  */
7796       if (skip_evaluation == 0 && integer_zerop (op1))
7797         warning (OPT_Wdiv_by_zero, "division by zero");
7798
7799       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7800            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7801           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7802               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7803         {
7804           enum tree_code tcode0 = code0, tcode1 = code1;
7805
7806           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7807             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7808           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7809             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7810
7811           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7812             resultcode = RDIV_EXPR;
7813           else
7814             /* Although it would be tempting to shorten always here, that
7815                loses on some targets, since the modulo instruction is
7816                undefined if the quotient can't be represented in the
7817                computation mode.  We shorten only if unsigned or if
7818                dividing by something we know != -1.  */
7819             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7820                        || (TREE_CODE (op1) == INTEGER_CST
7821                            && !integer_all_onesp (op1)));
7822           common = 1;
7823         }
7824       break;
7825
7826     case BIT_AND_EXPR:
7827     case BIT_IOR_EXPR:
7828     case BIT_XOR_EXPR:
7829       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7830         shorten = -1;
7831       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7832         common = 1;
7833       break;
7834
7835     case TRUNC_MOD_EXPR:
7836     case FLOOR_MOD_EXPR:
7837       if (skip_evaluation == 0 && integer_zerop (op1))
7838         warning (OPT_Wdiv_by_zero, "division by zero");
7839
7840       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7841         {
7842           /* Although it would be tempting to shorten always here, that loses
7843              on some targets, since the modulo instruction is undefined if the
7844              quotient can't be represented in the computation mode.  We shorten
7845              only if unsigned or if dividing by something we know != -1.  */
7846           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7847                      || (TREE_CODE (op1) == INTEGER_CST
7848                          && !integer_all_onesp (op1)));
7849           common = 1;
7850         }
7851       break;
7852
7853     case TRUTH_ANDIF_EXPR:
7854     case TRUTH_ORIF_EXPR:
7855     case TRUTH_AND_EXPR:
7856     case TRUTH_OR_EXPR:
7857     case TRUTH_XOR_EXPR:
7858       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7859            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7860           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7861               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7862         {
7863           /* Result of these operations is always an int,
7864              but that does not mean the operands should be
7865              converted to ints!  */
7866           result_type = integer_type_node;
7867           op0 = c_common_truthvalue_conversion (op0);
7868           op1 = c_common_truthvalue_conversion (op1);
7869           converted = 1;
7870         }
7871       break;
7872
7873       /* Shift operations: result has same type as first operand;
7874          always convert second operand to int.
7875          Also set SHORT_SHIFT if shifting rightward.  */
7876
7877     case RSHIFT_EXPR:
7878       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7879         {
7880           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7881             {
7882               if (tree_int_cst_sgn (op1) < 0)
7883                 warning (0, "right shift count is negative");
7884               else
7885                 {
7886                   if (!integer_zerop (op1))
7887                     short_shift = 1;
7888
7889                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7890                     warning (0, "right shift count >= width of type");
7891                 }
7892             }
7893
7894           /* Use the type of the value to be shifted.  */
7895           result_type = type0;
7896           /* Convert the shift-count to an integer, regardless of size
7897              of value being shifted.  */
7898           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7899             op1 = convert (integer_type_node, op1);
7900           /* Avoid converting op1 to result_type later.  */
7901           converted = 1;
7902         }
7903       break;
7904
7905     case LSHIFT_EXPR:
7906       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7907         {
7908           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7909             {
7910               if (tree_int_cst_sgn (op1) < 0)
7911                 warning (0, "left shift count is negative");
7912
7913               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7914                 warning (0, "left shift count >= width of type");
7915             }
7916
7917           /* Use the type of the value to be shifted.  */
7918           result_type = type0;
7919           /* Convert the shift-count to an integer, regardless of size
7920              of value being shifted.  */
7921           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7922             op1 = convert (integer_type_node, op1);
7923           /* Avoid converting op1 to result_type later.  */
7924           converted = 1;
7925         }
7926       break;
7927
7928     case EQ_EXPR:
7929     case NE_EXPR:
7930       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7931         warning (OPT_Wfloat_equal,
7932                  "comparing floating point with == or != is unsafe");
7933       /* Result of comparison is always int,
7934          but don't convert the args to int!  */
7935       build_type = integer_type_node;
7936       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7937            || code0 == COMPLEX_TYPE)
7938           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7939               || code1 == COMPLEX_TYPE))
7940         short_compare = 1;
7941       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7942         {
7943           tree tt0 = TREE_TYPE (type0);
7944           tree tt1 = TREE_TYPE (type1);
7945           /* Anything compares with void *.  void * compares with anything.
7946              Otherwise, the targets must be compatible
7947              and both must be object or both incomplete.  */
7948           if (comp_target_types (type0, type1))
7949             result_type = common_pointer_type (type0, type1);
7950           else if (VOID_TYPE_P (tt0))
7951             {
7952               /* op0 != orig_op0 detects the case of something
7953                  whose value is 0 but which isn't a valid null ptr const.  */
7954               if (pedantic && !null_pointer_constant_p (orig_op0)
7955                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7956                 pedwarn ("ISO C forbids comparison of %<void *%>"
7957                          " with function pointer");
7958             }
7959           else if (VOID_TYPE_P (tt1))
7960             {
7961               if (pedantic && !null_pointer_constant_p (orig_op1)
7962                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7963                 pedwarn ("ISO C forbids comparison of %<void *%>"
7964                          " with function pointer");
7965             }
7966           else
7967             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7968             if (!objc_ok)
7969               pedwarn ("comparison of distinct pointer types lacks a cast");
7970
7971           if (result_type == NULL_TREE)
7972             result_type = ptr_type_node;
7973         }
7974       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
7975         {
7976           if (TREE_CODE (op0) == ADDR_EXPR
7977               && DECL_P (TREE_OPERAND (op0, 0))
7978               && !DECL_WEAK (TREE_OPERAND (op0, 0)))
7979             warning (OPT_Walways_true, "the address of %qD will never be NULL",
7980                      TREE_OPERAND (op0, 0));
7981           result_type = type0;
7982         }
7983       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
7984         {
7985           if (TREE_CODE (op1) == ADDR_EXPR
7986               && DECL_P (TREE_OPERAND (op1, 0))
7987               && !DECL_WEAK (TREE_OPERAND (op1, 0)))
7988             warning (OPT_Walways_true, "the address of %qD will never be NULL",
7989                      TREE_OPERAND (op1, 0));
7990           result_type = type1;
7991         }
7992       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7993         {
7994           result_type = type0;
7995           pedwarn ("comparison between pointer and integer");
7996         }
7997       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7998         {
7999           result_type = type1;
8000           pedwarn ("comparison between pointer and integer");
8001         }
8002       break;
8003
8004     case LE_EXPR:
8005     case GE_EXPR:
8006     case LT_EXPR:
8007     case GT_EXPR:
8008       build_type = integer_type_node;
8009       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
8010           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
8011         short_compare = 1;
8012       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8013         {
8014           if (comp_target_types (type0, type1))
8015             {
8016               result_type = common_pointer_type (type0, type1);
8017               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8018                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8019                 pedwarn ("comparison of complete and incomplete pointers");
8020               else if (pedantic
8021                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8022                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8023             }
8024           else
8025             {
8026               result_type = ptr_type_node;
8027               pedwarn ("comparison of distinct pointer types lacks a cast");
8028             }
8029         }
8030       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8031         {
8032           result_type = type0;
8033           if (pedantic || extra_warnings)
8034             pedwarn ("ordered comparison of pointer with integer zero");
8035         }
8036       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8037         {
8038           result_type = type1;
8039           if (pedantic)
8040             pedwarn ("ordered comparison of pointer with integer zero");
8041         }
8042       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8043         {
8044           result_type = type0;
8045           pedwarn ("comparison between pointer and integer");
8046         }
8047       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8048         {
8049           result_type = type1;
8050           pedwarn ("comparison between pointer and integer");
8051         }
8052       break;
8053
8054     default:
8055       gcc_unreachable ();
8056     }
8057
8058   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8059     return error_mark_node;
8060
8061   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8062       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8063           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8064                                                     TREE_TYPE (type1))))
8065     {
8066       binary_op_error (code);
8067       return error_mark_node;
8068     }
8069
8070   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8071        || code0 == VECTOR_TYPE)
8072       &&
8073       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8074        || code1 == VECTOR_TYPE))
8075     {
8076       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8077
8078       if (shorten || common || short_compare)
8079         result_type = c_common_type (type0, type1);
8080
8081       /* For certain operations (which identify themselves by shorten != 0)
8082          if both args were extended from the same smaller type,
8083          do the arithmetic in that type and then extend.
8084
8085          shorten !=0 and !=1 indicates a bitwise operation.
8086          For them, this optimization is safe only if
8087          both args are zero-extended or both are sign-extended.
8088          Otherwise, we might change the result.
8089          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8090          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8091
8092       if (shorten && none_complex)
8093         {
8094           int unsigned0, unsigned1;
8095           tree arg0, arg1;
8096           int uns;
8097           tree type;
8098
8099           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8100              excessive narrowing when we call get_narrower below.  For
8101              example, suppose that OP0 is of unsigned int extended
8102              from signed char and that RESULT_TYPE is long long int.
8103              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8104              like
8105
8106                (long long int) (unsigned int) signed_char
8107
8108              which get_narrower would narrow down to
8109
8110                (unsigned int) signed char
8111
8112              If we do not cast OP0 first, get_narrower would return
8113              signed_char, which is inconsistent with the case of the
8114              explicit cast.  */
8115           op0 = convert (result_type, op0);
8116           op1 = convert (result_type, op1);
8117
8118           arg0 = get_narrower (op0, &unsigned0);
8119           arg1 = get_narrower (op1, &unsigned1);
8120
8121           /* UNS is 1 if the operation to be done is an unsigned one.  */
8122           uns = TYPE_UNSIGNED (result_type);
8123
8124           final_type = result_type;
8125
8126           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8127              but it *requires* conversion to FINAL_TYPE.  */
8128
8129           if ((TYPE_PRECISION (TREE_TYPE (op0))
8130                == TYPE_PRECISION (TREE_TYPE (arg0)))
8131               && TREE_TYPE (op0) != final_type)
8132             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8133           if ((TYPE_PRECISION (TREE_TYPE (op1))
8134                == TYPE_PRECISION (TREE_TYPE (arg1)))
8135               && TREE_TYPE (op1) != final_type)
8136             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8137
8138           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8139
8140           /* For bitwise operations, signedness of nominal type
8141              does not matter.  Consider only how operands were extended.  */
8142           if (shorten == -1)
8143             uns = unsigned0;
8144
8145           /* Note that in all three cases below we refrain from optimizing
8146              an unsigned operation on sign-extended args.
8147              That would not be valid.  */
8148
8149           /* Both args variable: if both extended in same way
8150              from same width, do it in that width.
8151              Do it unsigned if args were zero-extended.  */
8152           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8153                < TYPE_PRECISION (result_type))
8154               && (TYPE_PRECISION (TREE_TYPE (arg1))
8155                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8156               && unsigned0 == unsigned1
8157               && (unsigned0 || !uns))
8158             result_type
8159               = c_common_signed_or_unsigned_type
8160               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8161           else if (TREE_CODE (arg0) == INTEGER_CST
8162                    && (unsigned1 || !uns)
8163                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8164                        < TYPE_PRECISION (result_type))
8165                    && (type
8166                        = c_common_signed_or_unsigned_type (unsigned1,
8167                                                            TREE_TYPE (arg1)),
8168                        int_fits_type_p (arg0, type)))
8169             result_type = type;
8170           else if (TREE_CODE (arg1) == INTEGER_CST
8171                    && (unsigned0 || !uns)
8172                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8173                        < TYPE_PRECISION (result_type))
8174                    && (type
8175                        = c_common_signed_or_unsigned_type (unsigned0,
8176                                                            TREE_TYPE (arg0)),
8177                        int_fits_type_p (arg1, type)))
8178             result_type = type;
8179         }
8180
8181       /* Shifts can be shortened if shifting right.  */
8182
8183       if (short_shift)
8184         {
8185           int unsigned_arg;
8186           tree arg0 = get_narrower (op0, &unsigned_arg);
8187
8188           final_type = result_type;
8189
8190           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8191             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8192
8193           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8194               /* We can shorten only if the shift count is less than the
8195                  number of bits in the smaller type size.  */
8196               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8197               /* We cannot drop an unsigned shift after sign-extension.  */
8198               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8199             {
8200               /* Do an unsigned shift if the operand was zero-extended.  */
8201               result_type
8202                 = c_common_signed_or_unsigned_type (unsigned_arg,
8203                                                     TREE_TYPE (arg0));
8204               /* Convert value-to-be-shifted to that type.  */
8205               if (TREE_TYPE (op0) != result_type)
8206                 op0 = convert (result_type, op0);
8207               converted = 1;
8208             }
8209         }
8210
8211       /* Comparison operations are shortened too but differently.
8212          They identify themselves by setting short_compare = 1.  */
8213
8214       if (short_compare)
8215         {
8216           /* Don't write &op0, etc., because that would prevent op0
8217              from being kept in a register.
8218              Instead, make copies of the our local variables and
8219              pass the copies by reference, then copy them back afterward.  */
8220           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8221           enum tree_code xresultcode = resultcode;
8222           tree val
8223             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8224
8225           if (val != 0)
8226             return val;
8227
8228           op0 = xop0, op1 = xop1;
8229           converted = 1;
8230           resultcode = xresultcode;
8231
8232           if (warn_sign_compare && skip_evaluation == 0)
8233             {
8234               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8235               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8236               int unsignedp0, unsignedp1;
8237               tree primop0 = get_narrower (op0, &unsignedp0);
8238               tree primop1 = get_narrower (op1, &unsignedp1);
8239
8240               xop0 = orig_op0;
8241               xop1 = orig_op1;
8242               STRIP_TYPE_NOPS (xop0);
8243               STRIP_TYPE_NOPS (xop1);
8244
8245               /* Give warnings for comparisons between signed and unsigned
8246                  quantities that may fail.
8247
8248                  Do the checking based on the original operand trees, so that
8249                  casts will be considered, but default promotions won't be.
8250
8251                  Do not warn if the comparison is being done in a signed type,
8252                  since the signed type will only be chosen if it can represent
8253                  all the values of the unsigned type.  */
8254               if (!TYPE_UNSIGNED (result_type))
8255                 /* OK */;
8256               /* Do not warn if both operands are the same signedness.  */
8257               else if (op0_signed == op1_signed)
8258                 /* OK */;
8259               else
8260                 {
8261                   tree sop, uop;
8262
8263                   if (op0_signed)
8264                     sop = xop0, uop = xop1;
8265                   else
8266                     sop = xop1, uop = xop0;
8267
8268                   /* Do not warn if the signed quantity is an
8269                      unsuffixed integer literal (or some static
8270                      constant expression involving such literals or a
8271                      conditional expression involving such literals)
8272                      and it is non-negative.  */
8273                   if (tree_expr_nonnegative_p (sop))
8274                     /* OK */;
8275                   /* Do not warn if the comparison is an equality operation,
8276                      the unsigned quantity is an integral constant, and it
8277                      would fit in the result if the result were signed.  */
8278                   else if (TREE_CODE (uop) == INTEGER_CST
8279                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8280                            && int_fits_type_p
8281                            (uop, c_common_signed_type (result_type)))
8282                     /* OK */;
8283                   /* Do not warn if the unsigned quantity is an enumeration
8284                      constant and its maximum value would fit in the result
8285                      if the result were signed.  */
8286                   else if (TREE_CODE (uop) == INTEGER_CST
8287                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8288                            && int_fits_type_p
8289                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8290                             c_common_signed_type (result_type)))
8291                     /* OK */;
8292                   else
8293                     warning (0, "comparison between signed and unsigned");
8294                 }
8295
8296               /* Warn if two unsigned values are being compared in a size
8297                  larger than their original size, and one (and only one) is the
8298                  result of a `~' operator.  This comparison will always fail.
8299
8300                  Also warn if one operand is a constant, and the constant
8301                  does not have all bits set that are set in the ~ operand
8302                  when it is extended.  */
8303
8304               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8305                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8306                 {
8307                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8308                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8309                                             &unsignedp0);
8310                   else
8311                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8312                                             &unsignedp1);
8313
8314                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8315                     {
8316                       tree primop;
8317                       HOST_WIDE_INT constant, mask;
8318                       int unsignedp, bits;
8319
8320                       if (host_integerp (primop0, 0))
8321                         {
8322                           primop = primop1;
8323                           unsignedp = unsignedp1;
8324                           constant = tree_low_cst (primop0, 0);
8325                         }
8326                       else
8327                         {
8328                           primop = primop0;
8329                           unsignedp = unsignedp0;
8330                           constant = tree_low_cst (primop1, 0);
8331                         }
8332
8333                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8334                       if (bits < TYPE_PRECISION (result_type)
8335                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8336                         {
8337                           mask = (~(HOST_WIDE_INT) 0) << bits;
8338                           if ((mask & constant) != mask)
8339                             warning (0, "comparison of promoted ~unsigned with constant");
8340                         }
8341                     }
8342                   else if (unsignedp0 && unsignedp1
8343                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8344                                < TYPE_PRECISION (result_type))
8345                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8346                                < TYPE_PRECISION (result_type)))
8347                     warning (0, "comparison of promoted ~unsigned with unsigned");
8348                 }
8349             }
8350         }
8351     }
8352
8353   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8354      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8355      Then the expression will be built.
8356      It will be given type FINAL_TYPE if that is nonzero;
8357      otherwise, it will be given type RESULT_TYPE.  */
8358
8359   if (!result_type)
8360     {
8361       binary_op_error (code);
8362       return error_mark_node;
8363     }
8364
8365   if (!converted)
8366     {
8367       if (TREE_TYPE (op0) != result_type)
8368         op0 = convert_and_check (result_type, op0);
8369       if (TREE_TYPE (op1) != result_type)
8370         op1 = convert_and_check (result_type, op1);
8371
8372       /* This can happen if one operand has a vector type, and the other
8373          has a different type.  */
8374       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8375         return error_mark_node;
8376     }
8377
8378   if (build_type == NULL_TREE)
8379     build_type = result_type;
8380
8381   {
8382     /* Treat expressions in initializers specially as they can't trap.  */
8383     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8384                                                                     build_type,
8385                                                                     op0, op1)
8386                                          : fold_build2 (resultcode, build_type,
8387                                                         op0, op1);
8388
8389     if (final_type != 0)
8390       result = convert (final_type, result);
8391     return result;
8392   }
8393 }
8394
8395
8396 /* Convert EXPR to be a truth-value, validating its type for this
8397    purpose.  */
8398
8399 tree
8400 c_objc_common_truthvalue_conversion (tree expr)
8401 {
8402   switch (TREE_CODE (TREE_TYPE (expr)))
8403     {
8404     case ARRAY_TYPE:
8405       error ("used array that cannot be converted to pointer where scalar is required");
8406       return error_mark_node;
8407
8408     case RECORD_TYPE:
8409       error ("used struct type value where scalar is required");
8410       return error_mark_node;
8411
8412     case UNION_TYPE:
8413       error ("used union type value where scalar is required");
8414       return error_mark_node;
8415
8416     case FUNCTION_TYPE:
8417       gcc_unreachable ();
8418
8419     default:
8420       break;
8421     }
8422
8423   /* ??? Should we also give an error for void and vectors rather than
8424      leaving those to give errors later?  */
8425   return c_common_truthvalue_conversion (expr);
8426 }
8427 \f
8428
8429 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8430    required.  */
8431
8432 tree
8433 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8434                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8435 {
8436   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8437     {
8438       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8439       /* Executing a compound literal inside a function reinitializes
8440          it.  */
8441       if (!TREE_STATIC (decl))
8442         *se = true;
8443       return decl;
8444     }
8445   else
8446     return expr;
8447 }
8448
8449 \f
8450 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8451
8452 tree
8453 c_begin_omp_parallel (void)
8454 {
8455   tree block;
8456
8457   keep_next_level ();
8458   block = c_begin_compound_stmt (true);
8459
8460   return block;
8461 }
8462
8463 tree
8464 c_finish_omp_parallel (tree clauses, tree block)
8465 {
8466   tree stmt;
8467
8468   block = c_end_compound_stmt (block, true);
8469
8470   stmt = make_node (OMP_PARALLEL);
8471   TREE_TYPE (stmt) = void_type_node;
8472   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8473   OMP_PARALLEL_BODY (stmt) = block;
8474
8475   return add_stmt (stmt);
8476 }
8477
8478 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8479    Remove any elements from the list that are invalid.  */
8480
8481 tree
8482 c_finish_omp_clauses (tree clauses)
8483 {
8484   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8485   tree c, t, *pc = &clauses;
8486   const char *name;
8487
8488   bitmap_obstack_initialize (NULL);
8489   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8490   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8491   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8492
8493   for (pc = &clauses, c = clauses; c ; c = *pc)
8494     {
8495       bool remove = false;
8496       bool need_complete = false;
8497       bool need_implicitly_determined = false;
8498
8499       switch (OMP_CLAUSE_CODE (c))
8500         {
8501         case OMP_CLAUSE_SHARED:
8502           name = "shared";
8503           need_implicitly_determined = true;
8504           goto check_dup_generic;
8505
8506         case OMP_CLAUSE_PRIVATE:
8507           name = "private";
8508           need_complete = true;
8509           need_implicitly_determined = true;
8510           goto check_dup_generic;
8511
8512         case OMP_CLAUSE_REDUCTION:
8513           name = "reduction";
8514           need_implicitly_determined = true;
8515           t = OMP_CLAUSE_DECL (c);
8516           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8517               || POINTER_TYPE_P (TREE_TYPE (t)))
8518             {
8519               error ("%qE has invalid type for %<reduction%>", t);
8520               remove = true;
8521             }
8522           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8523             {
8524               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8525               const char *r_name = NULL;
8526
8527               switch (r_code)
8528                 {
8529                 case PLUS_EXPR:
8530                 case MULT_EXPR:
8531                 case MINUS_EXPR:
8532                   break;
8533                 case BIT_AND_EXPR:
8534                   r_name = "&";
8535                   break;
8536                 case BIT_XOR_EXPR:
8537                   r_name = "^";
8538                   break;
8539                 case BIT_IOR_EXPR:
8540                   r_name = "|";
8541                   break;
8542                 case TRUTH_ANDIF_EXPR:
8543                   r_name = "&&";
8544                   break;
8545                 case TRUTH_ORIF_EXPR:
8546                   r_name = "||";
8547                   break;
8548                 default:
8549                   gcc_unreachable ();
8550                 }
8551               if (r_name)
8552                 {
8553                   error ("%qE has invalid type for %<reduction(%s)%>",
8554                          t, r_name);
8555                   remove = true;
8556                 }
8557             }
8558           goto check_dup_generic;
8559
8560         case OMP_CLAUSE_COPYPRIVATE:
8561           name = "copyprivate";
8562           goto check_dup_generic;
8563
8564         case OMP_CLAUSE_COPYIN:
8565           name = "copyin";
8566           t = OMP_CLAUSE_DECL (c);
8567           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8568             {
8569               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8570               remove = true;
8571             }
8572           goto check_dup_generic;
8573
8574         check_dup_generic:
8575           t = OMP_CLAUSE_DECL (c);
8576           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8577             {
8578               error ("%qE is not a variable in clause %qs", t, name);
8579               remove = true;
8580             }
8581           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8582                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8583                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8584             {
8585               error ("%qE appears more than once in data clauses", t);
8586               remove = true;
8587             }
8588           else
8589             bitmap_set_bit (&generic_head, DECL_UID (t));
8590           break;
8591
8592         case OMP_CLAUSE_FIRSTPRIVATE:
8593           name = "firstprivate";
8594           t = OMP_CLAUSE_DECL (c);
8595           need_complete = true;
8596           need_implicitly_determined = true;
8597           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8598             {
8599               error ("%qE is not a variable in clause %<firstprivate%>", t);
8600               remove = true;
8601             }
8602           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8603                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8604             {
8605               error ("%qE appears more than once in data clauses", t);
8606               remove = true;
8607             }
8608           else
8609             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8610           break;
8611
8612         case OMP_CLAUSE_LASTPRIVATE:
8613           name = "lastprivate";
8614           t = OMP_CLAUSE_DECL (c);
8615           need_complete = true;
8616           need_implicitly_determined = true;
8617           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8618             {
8619               error ("%qE is not a variable in clause %<lastprivate%>", t);
8620               remove = true;
8621             }
8622           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8623                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8624             {
8625               error ("%qE appears more than once in data clauses", t);
8626               remove = true;
8627             }
8628           else
8629             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8630           break;
8631
8632         case OMP_CLAUSE_IF:
8633         case OMP_CLAUSE_NUM_THREADS:
8634         case OMP_CLAUSE_SCHEDULE:
8635         case OMP_CLAUSE_NOWAIT:
8636         case OMP_CLAUSE_ORDERED:
8637         case OMP_CLAUSE_DEFAULT:
8638           pc = &OMP_CLAUSE_CHAIN (c);
8639           continue;
8640
8641         default:
8642           gcc_unreachable ();
8643         }
8644
8645       if (!remove)
8646         {
8647           t = OMP_CLAUSE_DECL (c);
8648
8649           if (need_complete)
8650             {
8651               t = require_complete_type (t);
8652               if (t == error_mark_node)
8653                 remove = true;
8654             }
8655
8656           if (need_implicitly_determined)
8657             {
8658               const char *share_name = NULL;
8659
8660               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8661                 share_name = "threadprivate";
8662               else switch (c_omp_predetermined_sharing (t))
8663                 {
8664                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8665                   break;
8666                 case OMP_CLAUSE_DEFAULT_SHARED:
8667                   share_name = "shared";
8668                   break;
8669                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8670                   share_name = "private";
8671                   break;
8672                 default:
8673                   gcc_unreachable ();
8674                 }
8675               if (share_name)
8676                 {
8677                   error ("%qE is predetermined %qs for %qs",
8678                          t, share_name, name);
8679                   remove = true;
8680                 }
8681             }
8682         }
8683
8684       if (remove)
8685         *pc = OMP_CLAUSE_CHAIN (c);
8686       else
8687         pc = &OMP_CLAUSE_CHAIN (c);
8688     }
8689
8690   bitmap_obstack_release (NULL);
8691   return clauses;
8692 }