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 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "tree-gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static tree qualify_type (tree, tree);
  78 static int tagged_types_tu_compatible_p (tree, tree);
  79 static int comp_target_types (tree, tree);
  80 static int function_types_compatible_p (tree, tree);
  81 static int type_lists_compatible_p (tree, tree);
  82 static tree decl_constant_value_for_broken_optimization (tree);
  83 static tree lookup_field (tree, tree);
  84 static tree convert_arguments (tree, tree, tree, tree);
  85 static tree pointer_diff (tree, tree);
  86 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  87                                     int);
  88 static tree valid_compound_expr_initializer (tree, tree);
  89 static void push_string (const char *);
  90 static void push_member_name (tree);
  91 static void push_array_bounds (int);
  92 static int spelling_length (void);
  93 static char *print_spelling (char *);
  94 static void warning_init (const char *);
  95 static tree digest_init (tree, tree, bool, int);
  96 static void output_init_element (tree, bool, tree, tree, int);
  97 static void output_pending_init_elements (int);
  98 static int set_designator (int);
  99 static void push_range_stack (tree);
 100 static void add_pending_init (tree, tree);
 101 static void set_nonincremental_init (void);
 102 static void set_nonincremental_init_from_string (tree);
 103 static tree find_init_member (tree);
 104 static void readonly_error (tree, enum lvalue_use);
 105 static int lvalue_or_else (tree, enum lvalue_use);
 106 static int lvalue_p (tree);
 107 static void record_maybe_used_decl (tree);
 108 \f
 109 /* Do `exp = require_complete_type (exp);' to make sure exp
 110    does not have an incomplete type.  (That includes void types.)  */
 111
 112 tree
 113 require_complete_type (tree value)
 114 {
 115   tree type = TREE_TYPE (value);
 116
 117   if (value == error_mark_node || type == error_mark_node)
 118     return error_mark_node;
 119
 120   /* First, detect a valid value with a complete type.  */
 121   if (COMPLETE_TYPE_P (type))
 122     return value;
 123
 124   c_incomplete_type_error (value, type);
 125   return error_mark_node;
 126 }
 127
 128 /* Print an error message for invalid use of an incomplete type.
 129    VALUE is the expression that was used (or 0 if that isn't known)
 130    and TYPE is the type that was invalid.  */
 131
 132 void
 133 c_incomplete_type_error (tree value, tree type)
 134 {
 135   const char *type_code_string;
 136
 137   /* Avoid duplicate error message.  */
 138   if (TREE_CODE (type) == ERROR_MARK)
 139     return;
 140
 141   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 142                      || TREE_CODE (value) == PARM_DECL))
 143     error ("%qD has an incomplete type", value);
 144   else
 145     {
 146     retry:
 147       /* We must print an error message.  Be clever about what it says.  */
 148
 149       switch (TREE_CODE (type))
 150         {
 151         case RECORD_TYPE:
 152           type_code_string = "struct";
 153           break;
 154
 155         case UNION_TYPE:
 156           type_code_string = "union";
 157           break;
 158
 159         case ENUMERAL_TYPE:
 160           type_code_string = "enum";
 161           break;
 162
 163         case VOID_TYPE:
 164           error ("invalid use of void expression");
 165           return;
 166
 167         case ARRAY_TYPE:
 168           if (TYPE_DOMAIN (type))
 169             {
 170               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 171                 {
 172                   error ("invalid use of flexible array member");
 173                   return;
 174                 }
 175               type = TREE_TYPE (type);
 176               goto retry;
 177             }
 178           error ("invalid use of array with unspecified bounds");
 179           return;
 180
 181         default:
 182           gcc_unreachable ();
 183         }
 184
 185       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 186         error ("invalid use of undefined type %<%s %E%>",
 187                type_code_string, TYPE_NAME (type));
 188       else
 189         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 190         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 191     }
 192 }
 193
 194 /* Given a type, apply default promotions wrt unnamed function
 195    arguments and return the new type.  */
 196
 197 tree
 198 c_type_promotes_to (tree type)
 199 {
 200   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 201     return double_type_node;
 202
 203   if (c_promoting_integer_type_p (type))
 204     {
 205       /* Preserve unsignedness if not really getting any wider.  */
 206       if (TYPE_UNSIGNED (type)
 207           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 208         return unsigned_type_node;
 209       return integer_type_node;
 210     }
 211
 212   return type;
 213 }
 214
 215 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 216    as well as those of TYPE.  */
 217
 218 static tree
 219 qualify_type (tree type, tree like)
 220 {
 221   return c_build_qualified_type (type,
 222                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 223 }
 224 \f
 225 /* Return the composite type of two compatible types.
 226
 227    We assume that comptypes has already been done and returned
 228    nonzero; if that isn't so, this may crash.  In particular, we
 229    assume that qualifiers match.  */
 230
 231 tree
 232 composite_type (tree t1, tree t2)
 233 {
 234   enum tree_code code1;
 235   enum tree_code code2;
 236   tree attributes;
 237
 238   /* Save time if the two types are the same.  */
 239
 240   if (t1 == t2) return t1;
 241
 242   /* If one type is nonsense, use the other.  */
 243   if (t1 == error_mark_node)
 244     return t2;
 245   if (t2 == error_mark_node)
 246     return t1;
 247
 248   code1 = TREE_CODE (t1);
 249   code2 = TREE_CODE (t2);
 250
 251   /* Merge the attributes.  */
 252   attributes = targetm.merge_type_attributes (t1, t2);
 253
 254   /* If one is an enumerated type and the other is the compatible
 255      integer type, the composite type might be either of the two
 256      (DR#013 question 3).  For consistency, use the enumerated type as
 257      the composite type.  */
 258
 259   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 260     return t1;
 261   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 262     return t2;
 263
 264   gcc_assert (code1 == code2);
 265
 266   switch (code1)
 267     {
 268     case POINTER_TYPE:
 269       /* For two pointers, do this recursively on the target type.  */
 270       {
 271         tree pointed_to_1 = TREE_TYPE (t1);
 272         tree pointed_to_2 = TREE_TYPE (t2);
 273         tree target = composite_type (pointed_to_1, pointed_to_2);
 274         t1 = build_pointer_type (target);
 275         t1 = build_type_attribute_variant (t1, attributes);
 276         return qualify_type (t1, t2);
 277       }
 278
 279     case ARRAY_TYPE:
 280       {
 281         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 282         int quals;
 283         tree unqual_elt;
 284         tree d1 = TYPE_DOMAIN (t1);
 285         tree d2 = TYPE_DOMAIN (t2);
 286         bool d1_variable, d2_variable;
 287         bool d1_zero, d2_zero;
 288
 289         /* We should not have any type quals on arrays at all.  */
 290         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 291
 292         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 293         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 294
 295         d1_variable = (!d1_zero
 296                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 297                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 298         d2_variable = (!d2_zero
 299                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 300                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 301
 302         /* Save space: see if the result is identical to one of the args.  */
 303         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 304             && (d2_variable || d2_zero || !d1_variable))
 305           return build_type_attribute_variant (t1, attributes);
 306         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 307             && (d1_variable || d1_zero || !d2_variable))
 308           return build_type_attribute_variant (t2, attributes);
 309
 310         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 311           return build_type_attribute_variant (t1, attributes);
 312         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 313           return build_type_attribute_variant (t2, attributes);
 314
 315         /* Merge the element types, and have a size if either arg has
 316            one.  We may have qualifiers on the element types.  To set
 317            up TYPE_MAIN_VARIANT correctly, we need to form the
 318            composite of the unqualified types and add the qualifiers
 319            back at the end.  */
 320         quals = TYPE_QUALS (strip_array_types (elt));
 321         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 322         t1 = build_array_type (unqual_elt,
 323                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 324                                              && (d2_variable
 325                                                  || d2_zero
 326                                                  || !d1_variable))
 327                                             ? t1
 328                                             : t2));
 329         t1 = c_build_qualified_type (t1, quals);
 330         return build_type_attribute_variant (t1, attributes);
 331       }
 332
 333     case FUNCTION_TYPE:
 334       /* Function types: prefer the one that specified arg types.
 335          If both do, merge the arg types.  Also merge the return types.  */
 336       {
 337         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 338         tree p1 = TYPE_ARG_TYPES (t1);
 339         tree p2 = TYPE_ARG_TYPES (t2);
 340         int len;
 341         tree newargs, n;
 342         int i;
 343
 344         /* Save space: see if the result is identical to one of the args.  */
 345         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 346           return build_type_attribute_variant (t1, attributes);
 347         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 348           return build_type_attribute_variant (t2, attributes);
 349
 350         /* Simple way if one arg fails to specify argument types.  */
 351         if (TYPE_ARG_TYPES (t1) == 0)
 352          {
 353             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 354             t1 = build_type_attribute_variant (t1, attributes);
 355             return qualify_type (t1, t2);
 356          }
 357         if (TYPE_ARG_TYPES (t2) == 0)
 358          {
 359            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 360            t1 = build_type_attribute_variant (t1, attributes);
 361            return qualify_type (t1, t2);
 362          }
 363
 364         /* If both args specify argument types, we must merge the two
 365            lists, argument by argument.  */
 366         /* Tell global_bindings_p to return false so that variable_size
 367            doesn't die on VLAs in parameter types.  */
 368         c_override_global_bindings_to_false = true;
 369
 370         len = list_length (p1);
 371         newargs = 0;
 372
 373         for (i = 0; i < len; i++)
 374           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 375
 376         n = newargs;
 377
 378         for (; p1;
 379              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 380           {
 381             /* A null type means arg type is not specified.
 382                Take whatever the other function type has.  */
 383             if (TREE_VALUE (p1) == 0)
 384               {
 385                 TREE_VALUE (n) = TREE_VALUE (p2);
 386                 goto parm_done;
 387               }
 388             if (TREE_VALUE (p2) == 0)
 389               {
 390                 TREE_VALUE (n) = TREE_VALUE (p1);
 391                 goto parm_done;
 392               }
 393
 394             /* Given  wait (union {union wait *u; int *i} *)
 395                and  wait (union wait *),
 396                prefer  union wait *  as type of parm.  */
 397             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 398                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 399               {
 400                 tree memb;
 401                 tree mv2 = TREE_VALUE (p2);
 402                 if (mv2 && mv2 != error_mark_node
 403                     && TREE_CODE (mv2) != ARRAY_TYPE)
 404                   mv2 = TYPE_MAIN_VARIANT (mv2);
 405                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 406                      memb; memb = TREE_CHAIN (memb))
 407                   {
 408                     tree mv3 = TREE_TYPE (memb);
 409                     if (mv3 && mv3 != error_mark_node
 410                         && TREE_CODE (mv3) != ARRAY_TYPE)
 411                       mv3 = TYPE_MAIN_VARIANT (mv3);
 412                     if (comptypes (mv3, mv2))
 413                       {
 414                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 415                                                          TREE_VALUE (p2));
 416                         if (pedantic)
 417                           pedwarn ("function types not truly compatible in ISO C");
 418                         goto parm_done;
 419                       }
 420                   }
 421               }
 422             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 423                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 424               {
 425                 tree memb;
 426                 tree mv1 = TREE_VALUE (p1);
 427                 if (mv1 && mv1 != error_mark_node
 428                     && TREE_CODE (mv1) != ARRAY_TYPE)
 429                   mv1 = TYPE_MAIN_VARIANT (mv1);
 430                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 431                      memb; memb = TREE_CHAIN (memb))
 432                   {
 433                     tree mv3 = TREE_TYPE (memb);
 434                     if (mv3 && mv3 != error_mark_node
 435                         && TREE_CODE (mv3) != ARRAY_TYPE)
 436                       mv3 = TYPE_MAIN_VARIANT (mv3);
 437                     if (comptypes (mv3, mv1))
 438                       {
 439                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 440                                                          TREE_VALUE (p1));
 441                         if (pedantic)
 442                           pedwarn ("function types not truly compatible in ISO C");
 443                         goto parm_done;
 444                       }
 445                   }
 446               }
 447             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 448           parm_done: ;
 449           }
 450
 451         c_override_global_bindings_to_false = false;
 452         t1 = build_function_type (valtype, newargs);
 453         t1 = qualify_type (t1, t2);
 454         /* ... falls through ...  */
 455       }
 456
 457     default:
 458       return build_type_attribute_variant (t1, attributes);
 459     }
 460
 461 }
 462
 463 /* Return the type of a conditional expression between pointers to
 464    possibly differently qualified versions of compatible types.
 465
 466    We assume that comp_target_types has already been done and returned
 467    nonzero; if that isn't so, this may crash.  */
 468
 469 static tree
 470 common_pointer_type (tree t1, tree t2)
 471 {
 472   tree attributes;
 473   tree pointed_to_1, mv1;
 474   tree pointed_to_2, mv2;
 475   tree target;
 476
 477   /* Save time if the two types are the same.  */
 478
 479   if (t1 == t2) return t1;
 480
 481   /* If one type is nonsense, use the other.  */
 482   if (t1 == error_mark_node)
 483     return t2;
 484   if (t2 == error_mark_node)
 485     return t1;
 486
 487   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 488               && TREE_CODE (t2) == POINTER_TYPE);
 489
 490   /* Merge the attributes.  */
 491   attributes = targetm.merge_type_attributes (t1, t2);
 492
 493   /* Find the composite type of the target types, and combine the
 494      qualifiers of the two types' targets.  Do not lose qualifiers on
 495      array element types by taking the TYPE_MAIN_VARIANT.  */
 496   mv1 = pointed_to_1 = TREE_TYPE (t1);
 497   mv2 = pointed_to_2 = TREE_TYPE (t2);
 498   if (TREE_CODE (mv1) != ARRAY_TYPE)
 499     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 500   if (TREE_CODE (mv2) != ARRAY_TYPE)
 501     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 502   target = composite_type (mv1, mv2);
 503   t1 = build_pointer_type (c_build_qualified_type
 504                            (target,
 505                             TYPE_QUALS (pointed_to_1) |
 506                             TYPE_QUALS (pointed_to_2)));
 507   return build_type_attribute_variant (t1, attributes);
 508 }
 509
 510 /* Return the common type for two arithmetic types under the usual
 511    arithmetic conversions.  The default conversions have already been
 512    applied, and enumerated types converted to their compatible integer
 513    types.  The resulting type is unqualified and has no attributes.
 514
 515    This is the type for the result of most arithmetic operations
 516    if the operands have the given two types.  */
 517
 518 static tree
 519 c_common_type (tree t1, tree t2)
 520 {
 521   enum tree_code code1;
 522   enum tree_code code2;
 523
 524   /* If one type is nonsense, use the other.  */
 525   if (t1 == error_mark_node)
 526     return t2;
 527   if (t2 == error_mark_node)
 528     return t1;
 529
 530   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 531     t1 = TYPE_MAIN_VARIANT (t1);
 532
 533   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 534     t2 = TYPE_MAIN_VARIANT (t2);
 535
 536   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 537     t1 = build_type_attribute_variant (t1, NULL_TREE);
 538
 539   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 540     t2 = build_type_attribute_variant (t2, NULL_TREE);
 541
 542   /* Save time if the two types are the same.  */
 543
 544   if (t1 == t2) return t1;
 545
 546   code1 = TREE_CODE (t1);
 547   code2 = TREE_CODE (t2);
 548
 549   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 550               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 551   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 552               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 553
 554   /* If one type is a vector type, return that type.  (How the usual
 555      arithmetic conversions apply to the vector types extension is not
 556      precisely specified.)  */
 557   if (code1 == VECTOR_TYPE)
 558     return t1;
 559
 560   if (code2 == VECTOR_TYPE)
 561     return t2;
 562
 563   /* If one type is complex, form the common type of the non-complex
 564      components, then make that complex.  Use T1 or T2 if it is the
 565      required type.  */
 566   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 567     {
 568       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 569       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 570       tree subtype = c_common_type (subtype1, subtype2);
 571
 572       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 573         return t1;
 574       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 575         return t2;
 576       else
 577         return build_complex_type (subtype);
 578     }
 579
 580   /* If only one is real, use it as the result.  */
 581
 582   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 583     return t1;
 584
 585   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 586     return t2;
 587
 588   /* Both real or both integers; use the one with greater precision.  */
 589
 590   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 591     return t1;
 592   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 593     return t2;
 594
 595   /* Same precision.  Prefer long longs to longs to ints when the
 596      same precision, following the C99 rules on integer type rank
 597      (which are equivalent to the C90 rules for C90 types).  */
 598
 599   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 600       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 601     return long_long_unsigned_type_node;
 602
 603   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 604       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 605     {
 606       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 607         return long_long_unsigned_type_node;
 608       else
 609         return long_long_integer_type_node;
 610     }
 611
 612   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 613       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 614     return long_unsigned_type_node;
 615
 616   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 617       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 618     {
 619       /* But preserve unsignedness from the other type,
 620          since long cannot hold all the values of an unsigned int.  */
 621       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 622         return long_unsigned_type_node;
 623       else
 624         return long_integer_type_node;
 625     }
 626
 627   /* Likewise, prefer long double to double even if same size.  */
 628   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 629       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 630     return long_double_type_node;
 631
 632   /* Otherwise prefer the unsigned one.  */
 633
 634   if (TYPE_UNSIGNED (t1))
 635     return t1;
 636   else
 637     return t2;
 638 }
 639 \f
 640 /* Wrapper around c_common_type that is used by c-common.c.  ENUMERAL_TYPEs
 641    are allowed here and are converted to their compatible integer types.
 642    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 643    preferably a non-Boolean type as the common type.  */
 644 tree
 645 common_type (tree t1, tree t2)
 646 {
 647   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 648     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 649   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 650     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 651
 652   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 653   if (TREE_CODE (t1) == BOOLEAN_TYPE
 654       && TREE_CODE (t2) == BOOLEAN_TYPE)
 655     return boolean_type_node;
 656
 657   /* If either type is BOOLEAN_TYPE, then return the other.  */
 658   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 659     return t2;
 660   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 661     return t1;
 662
 663   return c_common_type (t1, t2);
 664 }
 665 \f
 666 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 667    or various other operations.  Return 2 if they are compatible
 668    but a warning may be needed if you use them together.  */
 669
 670 int
 671 comptypes (tree type1, tree type2)
 672 {
 673   tree t1 = type1;
 674   tree t2 = type2;
 675   int attrval, val;
 676
 677   /* Suppress errors caused by previously reported errors.  */
 678
 679   if (t1 == t2 || !t1 || !t2
 680       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 681     return 1;
 682
 683   /* If either type is the internal version of sizetype, return the
 684      language version.  */
 685   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 686       && TYPE_ORIG_SIZE_TYPE (t1))
 687     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 688
 689   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 690       && TYPE_ORIG_SIZE_TYPE (t2))
 691     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 692
 693
 694   /* Enumerated types are compatible with integer types, but this is
 695      not transitive: two enumerated types in the same translation unit
 696      are compatible with each other only if they are the same type.  */
 697
 698   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 699     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 700   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 701     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 702
 703   if (t1 == t2)
 704     return 1;
 705
 706   /* Different classes of types can't be compatible.  */
 707
 708   if (TREE_CODE (t1) != TREE_CODE (t2))
 709     return 0;
 710
 711   /* Qualifiers must match. C99 6.7.3p9 */
 712
 713   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 714     return 0;
 715
 716   /* Allow for two different type nodes which have essentially the same
 717      definition.  Note that we already checked for equality of the type
 718      qualifiers (just above).  */
 719
 720   if (TREE_CODE (t1) != ARRAY_TYPE
 721       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 722     return 1;
 723
 724   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 725   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 726      return 0;
 727
 728   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 729   val = 0;
 730
 731   switch (TREE_CODE (t1))
 732     {
 733     case POINTER_TYPE:
 734       /* Do not remove mode or aliasing information.  */
 735       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 736           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 737         break;
 738       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 739              ? 1 : comptypes (TREE_TYPE (t1), TREE_TYPE (t2)));
 740       break;
 741
 742     case FUNCTION_TYPE:
 743       val = function_types_compatible_p (t1, t2);
 744       break;
 745
 746     case ARRAY_TYPE:
 747       {
 748         tree d1 = TYPE_DOMAIN (t1);
 749         tree d2 = TYPE_DOMAIN (t2);
 750         bool d1_variable, d2_variable;
 751         bool d1_zero, d2_zero;
 752         val = 1;
 753
 754         /* Target types must match incl. qualifiers.  */
 755         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 756             && 0 == (val = comptypes (TREE_TYPE (t1), TREE_TYPE (t2))))
 757           return 0;
 758
 759         /* Sizes must match unless one is missing or variable.  */
 760         if (d1 == 0 || d2 == 0 || d1 == d2)
 761           break;
 762
 763         d1_zero = !TYPE_MAX_VALUE (d1);
 764         d2_zero = !TYPE_MAX_VALUE (d2);
 765
 766         d1_variable = (!d1_zero
 767                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 768                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 769         d2_variable = (!d2_zero
 770                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 771                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 772
 773         if (d1_variable || d2_variable)
 774           break;
 775         if (d1_zero && d2_zero)
 776           break;
 777         if (d1_zero || d2_zero
 778             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 779             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 780           val = 0;
 781
 782         break;
 783       }
 784
 785     case ENUMERAL_TYPE:
 786     case RECORD_TYPE:
 787     case UNION_TYPE:
 788       if (val != 1 && !same_translation_unit_p (t1, t2))
 789         val = tagged_types_tu_compatible_p (t1, t2);
 790       break;
 791
 792     case VECTOR_TYPE:
 793       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 794             && comptypes (TREE_TYPE (t1), TREE_TYPE (t2));
 795       break;
 796
 797     default:
 798       break;
 799     }
 800   return attrval == 2 && val == 1 ? 2 : val;
 801 }
 802
 803 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 804    ignoring their qualifiers.  */
 805
 806 static int
 807 comp_target_types (tree ttl, tree ttr)
 808 {
 809   int val;
 810   tree mvl, mvr;
 811
 812   /* Do not lose qualifiers on element types of array types that are
 813      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 814   mvl = TREE_TYPE (ttl);
 815   mvr = TREE_TYPE (ttr);
 816   if (TREE_CODE (mvl) != ARRAY_TYPE)
 817     mvl = TYPE_MAIN_VARIANT (mvl);
 818   if (TREE_CODE (mvr) != ARRAY_TYPE)
 819     mvr = TYPE_MAIN_VARIANT (mvr);
 820   val = comptypes (mvl, mvr);
 821
 822   if (val == 2 && pedantic)
 823     pedwarn ("types are not quite compatible");
 824   return val;
 825 }
 826 \f
 827 /* Subroutines of `comptypes'.  */
 828
 829 /* Determine whether two trees derive from the same translation unit.
 830    If the CONTEXT chain ends in a null, that tree's context is still
 831    being parsed, so if two trees have context chains ending in null,
 832    they're in the same translation unit.  */
 833 int
 834 same_translation_unit_p (tree t1, tree t2)
 835 {
 836   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 837     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 838       {
 839       case tcc_declaration:
 840         t1 = DECL_CONTEXT (t1); break;
 841       case tcc_type:
 842         t1 = TYPE_CONTEXT (t1); break;
 843       case tcc_exceptional:
 844         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 845       default: gcc_unreachable ();
 846       }
 847
 848   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 849     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 850       {
 851       case tcc_declaration:
 852         t2 = DECL_CONTEXT (t2); break;
 853       case tcc_type:
 854         t2 = TYPE_CONTEXT (t2); break;
 855       case tcc_exceptional:
 856         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 857       default: gcc_unreachable ();
 858       }
 859
 860   return t1 == t2;
 861 }
 862
 863 /* The C standard says that two structures in different translation
 864    units are compatible with each other only if the types of their
 865    fields are compatible (among other things).  So, consider two copies
 866    of this structure:  */
 867
 868 struct tagged_tu_seen {
 869   const struct tagged_tu_seen * next;
 870   tree t1;
 871   tree t2;
 872 };
 873
 874 /* Can they be compatible with each other?  We choose to break the
 875    recursion by allowing those types to be compatible.  */
 876
 877 static const struct tagged_tu_seen * tagged_tu_seen_base;
 878
 879 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 880    compatible.  If the two types are not the same (which has been
 881    checked earlier), this can only happen when multiple translation
 882    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 883    rules.  */
 884
 885 static int
 886 tagged_types_tu_compatible_p (tree t1, tree t2)
 887 {
 888   tree s1, s2;
 889   bool needs_warning = false;
 890
 891   /* We have to verify that the tags of the types are the same.  This
 892      is harder than it looks because this may be a typedef, so we have
 893      to go look at the original type.  It may even be a typedef of a
 894      typedef...
 895      In the case of compiler-created builtin structs the TYPE_DECL
 896      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 897   while (TYPE_NAME (t1)
 898          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 899          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 900     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 901
 902   while (TYPE_NAME (t2)
 903          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
 904          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
 905     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
 906
 907   /* C90 didn't have the requirement that the two tags be the same.  */
 908   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
 909     return 0;
 910
 911   /* C90 didn't say what happened if one or both of the types were
 912      incomplete; we choose to follow C99 rules here, which is that they
 913      are compatible.  */
 914   if (TYPE_SIZE (t1) == NULL
 915       || TYPE_SIZE (t2) == NULL)
 916     return 1;
 917
 918   {
 919     const struct tagged_tu_seen * tts_i;
 920     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
 921       if (tts_i->t1 == t1 && tts_i->t2 == t2)
 922         return 1;
 923   }
 924
 925   switch (TREE_CODE (t1))
 926     {
 927     case ENUMERAL_TYPE:
 928       {
 929
 930         /* Speed up the case where the type values are in the same order.  */
 931         tree tv1 = TYPE_VALUES (t1);
 932         tree tv2 = TYPE_VALUES (t2);
 933
 934         if (tv1 == tv2)
 935           return 1;
 936
 937         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
 938           {
 939             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
 940               break;
 941             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
 942               return 0;
 943           }
 944
 945         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
 946           return 1;
 947         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
 948           return 0;
 949
 950         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
 951           return 0;
 952
 953         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
 954           {
 955             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
 956             if (s2 == NULL
 957                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
 958               return 0;
 959           }
 960         return 1;
 961       }
 962
 963     case UNION_TYPE:
 964       {
 965         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
 966           return 0;
 967
 968         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
 969           {
 970             bool ok = false;
 971             struct tagged_tu_seen tts;
 972
 973             tts.next = tagged_tu_seen_base;
 974             tts.t1 = t1;
 975             tts.t2 = t2;
 976             tagged_tu_seen_base = &tts;
 977
 978             if (DECL_NAME (s1) != NULL)
 979               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
 980                 if (DECL_NAME (s1) == DECL_NAME (s2))
 981                   {
 982                     int result;
 983                     result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
 984                     if (result == 0)
 985                       break;
 986                     if (result == 2)
 987                       needs_warning = true;
 988
 989                     if (TREE_CODE (s1) == FIELD_DECL
 990                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
 991                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
 992                       break;
 993
 994                     ok = true;
 995                     break;
 996                   }
 997             tagged_tu_seen_base = tts.next;
 998             if (!ok)
 999               return 0;
1000           }
1001         return needs_warning ? 2 : 1;
1002       }
1003
1004     case RECORD_TYPE:
1005       {
1006         struct tagged_tu_seen tts;
1007
1008         tts.next = tagged_tu_seen_base;
1009         tts.t1 = t1;
1010         tts.t2 = t2;
1011         tagged_tu_seen_base = &tts;
1012
1013         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1014              s1 && s2;
1015              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1016           {
1017             int result;
1018             if (TREE_CODE (s1) != TREE_CODE (s2)
1019                 || DECL_NAME (s1) != DECL_NAME (s2))
1020               break;
1021             result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
1022             if (result == 0)
1023               break;
1024             if (result == 2)
1025               needs_warning = true;
1026
1027             if (TREE_CODE (s1) == FIELD_DECL
1028                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1029                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1030               break;
1031           }
1032         tagged_tu_seen_base = tts.next;
1033         if (s1 && s2)
1034           return 0;
1035         return needs_warning ? 2 : 1;
1036       }
1037
1038     default:
1039       gcc_unreachable ();
1040     }
1041 }
1042
1043 /* Return 1 if two function types F1 and F2 are compatible.
1044    If either type specifies no argument types,
1045    the other must specify a fixed number of self-promoting arg types.
1046    Otherwise, if one type specifies only the number of arguments,
1047    the other must specify that number of self-promoting arg types.
1048    Otherwise, the argument types must match.  */
1049
1050 static int
1051 function_types_compatible_p (tree f1, tree f2)
1052 {
1053   tree args1, args2;
1054   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1055   int val = 1;
1056   int val1;
1057   tree ret1, ret2;
1058
1059   ret1 = TREE_TYPE (f1);
1060   ret2 = TREE_TYPE (f2);
1061
1062   /* 'volatile' qualifiers on a function's return type used to mean
1063      the function is noreturn.  */
1064   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1065     pedwarn ("function return types not compatible due to %<volatile%>");
1066   if (TYPE_VOLATILE (ret1))
1067     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1068                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1069   if (TYPE_VOLATILE (ret2))
1070     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1071                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1072   val = comptypes (ret1, ret2);
1073   if (val == 0)
1074     return 0;
1075
1076   args1 = TYPE_ARG_TYPES (f1);
1077   args2 = TYPE_ARG_TYPES (f2);
1078
1079   /* An unspecified parmlist matches any specified parmlist
1080      whose argument types don't need default promotions.  */
1081
1082   if (args1 == 0)
1083     {
1084       if (!self_promoting_args_p (args2))
1085         return 0;
1086       /* If one of these types comes from a non-prototype fn definition,
1087          compare that with the other type's arglist.
1088          If they don't match, ask for a warning (but no error).  */
1089       if (TYPE_ACTUAL_ARG_TYPES (f1)
1090           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1091         val = 2;
1092       return val;
1093     }
1094   if (args2 == 0)
1095     {
1096       if (!self_promoting_args_p (args1))
1097         return 0;
1098       if (TYPE_ACTUAL_ARG_TYPES (f2)
1099           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1100         val = 2;
1101       return val;
1102     }
1103
1104   /* Both types have argument lists: compare them and propagate results.  */
1105   val1 = type_lists_compatible_p (args1, args2);
1106   return val1 != 1 ? val1 : val;
1107 }
1108
1109 /* Check two lists of types for compatibility,
1110    returning 0 for incompatible, 1 for compatible,
1111    or 2 for compatible with warning.  */
1112
1113 static int
1114 type_lists_compatible_p (tree args1, tree args2)
1115 {
1116   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1117   int val = 1;
1118   int newval = 0;
1119
1120   while (1)
1121     {
1122       tree a1, mv1, a2, mv2;
1123       if (args1 == 0 && args2 == 0)
1124         return val;
1125       /* If one list is shorter than the other,
1126          they fail to match.  */
1127       if (args1 == 0 || args2 == 0)
1128         return 0;
1129       mv1 = a1 = TREE_VALUE (args1);
1130       mv2 = a2 = TREE_VALUE (args2);
1131       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1132         mv1 = TYPE_MAIN_VARIANT (mv1);
1133       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1134         mv2 = TYPE_MAIN_VARIANT (mv2);
1135       /* A null pointer instead of a type
1136          means there is supposed to be an argument
1137          but nothing is specified about what type it has.
1138          So match anything that self-promotes.  */
1139       if (a1 == 0)
1140         {
1141           if (c_type_promotes_to (a2) != a2)
1142             return 0;
1143         }
1144       else if (a2 == 0)
1145         {
1146           if (c_type_promotes_to (a1) != a1)
1147             return 0;
1148         }
1149       /* If one of the lists has an error marker, ignore this arg.  */
1150       else if (TREE_CODE (a1) == ERROR_MARK
1151                || TREE_CODE (a2) == ERROR_MARK)
1152         ;
1153       else if (!(newval = comptypes (mv1, mv2)))
1154         {
1155           /* Allow  wait (union {union wait *u; int *i} *)
1156              and  wait (union wait *)  to be compatible.  */
1157           if (TREE_CODE (a1) == UNION_TYPE
1158               && (TYPE_NAME (a1) == 0
1159                   || TYPE_TRANSPARENT_UNION (a1))
1160               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1161               && tree_int_cst_equal (TYPE_SIZE (a1),
1162                                      TYPE_SIZE (a2)))
1163             {
1164               tree memb;
1165               for (memb = TYPE_FIELDS (a1);
1166                    memb; memb = TREE_CHAIN (memb))
1167                 {
1168                   tree mv3 = TREE_TYPE (memb);
1169                   if (mv3 && mv3 != error_mark_node
1170                       && TREE_CODE (mv3) != ARRAY_TYPE)
1171                     mv3 = TYPE_MAIN_VARIANT (mv3);
1172                   if (comptypes (mv3, mv2))
1173                     break;
1174                 }
1175               if (memb == 0)
1176                 return 0;
1177             }
1178           else if (TREE_CODE (a2) == UNION_TYPE
1179                    && (TYPE_NAME (a2) == 0
1180                        || TYPE_TRANSPARENT_UNION (a2))
1181                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1182                    && tree_int_cst_equal (TYPE_SIZE (a2),
1183                                           TYPE_SIZE (a1)))
1184             {
1185               tree memb;
1186               for (memb = TYPE_FIELDS (a2);
1187                    memb; memb = TREE_CHAIN (memb))
1188                 {
1189                   tree mv3 = TREE_TYPE (memb);
1190                   if (mv3 && mv3 != error_mark_node
1191                       && TREE_CODE (mv3) != ARRAY_TYPE)
1192                     mv3 = TYPE_MAIN_VARIANT (mv3);
1193                   if (comptypes (mv3, mv1))
1194                     break;
1195                 }
1196               if (memb == 0)
1197                 return 0;
1198             }
1199           else
1200             return 0;
1201         }
1202
1203       /* comptypes said ok, but record if it said to warn.  */
1204       if (newval > val)
1205         val = newval;
1206
1207       args1 = TREE_CHAIN (args1);
1208       args2 = TREE_CHAIN (args2);
1209     }
1210 }
1211 \f
1212 /* Compute the size to increment a pointer by.  */
1213
1214 static tree
1215 c_size_in_bytes (tree type)
1216 {
1217   enum tree_code code = TREE_CODE (type);
1218
1219   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1220     return size_one_node;
1221
1222   if (!COMPLETE_OR_VOID_TYPE_P (type))
1223     {
1224       error ("arithmetic on pointer to an incomplete type");
1225       return size_one_node;
1226     }
1227
1228   /* Convert in case a char is more than one unit.  */
1229   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1230                      size_int (TYPE_PRECISION (char_type_node)
1231                                / BITS_PER_UNIT));
1232 }
1233 \f
1234 /* Return either DECL or its known constant value (if it has one).  */
1235
1236 tree
1237 decl_constant_value (tree decl)
1238 {
1239   if (/* Don't change a variable array bound or initial value to a constant
1240          in a place where a variable is invalid.  Note that DECL_INITIAL
1241          isn't valid for a PARM_DECL.  */
1242       current_function_decl != 0
1243       && TREE_CODE (decl) != PARM_DECL
1244       && !TREE_THIS_VOLATILE (decl)
1245       && TREE_READONLY (decl)
1246       && DECL_INITIAL (decl) != 0
1247       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1248       /* This is invalid if initial value is not constant.
1249          If it has either a function call, a memory reference,
1250          or a variable, then re-evaluating it could give different results.  */
1251       && TREE_CONSTANT (DECL_INITIAL (decl))
1252       /* Check for cases where this is sub-optimal, even though valid.  */
1253       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1254     return DECL_INITIAL (decl);
1255   return decl;
1256 }
1257
1258 /* Return either DECL or its known constant value (if it has one), but
1259    return DECL if pedantic or DECL has mode BLKmode.  This is for
1260    bug-compatibility with the old behavior of decl_constant_value
1261    (before GCC 3.0); every use of this function is a bug and it should
1262    be removed before GCC 3.1.  It is not appropriate to use pedantic
1263    in a way that affects optimization, and BLKmode is probably not the
1264    right test for avoiding misoptimizations either.  */
1265
1266 static tree
1267 decl_constant_value_for_broken_optimization (tree decl)
1268 {
1269   tree ret;
1270
1271   if (pedantic || DECL_MODE (decl) == BLKmode)
1272     return decl;
1273
1274   ret = decl_constant_value (decl);
1275   /* Avoid unwanted tree sharing between the initializer and current
1276      function's body where the tree can be modified e.g. by the
1277      gimplifier.  */
1278   if (ret != decl && TREE_STATIC (decl))
1279     ret = unshare_expr (ret);
1280   return ret;
1281 }
1282
1283 /* Convert the array expression EXP to a pointer.  */
1284 static tree
1285 array_to_pointer_conversion (tree exp)
1286 {
1287   tree orig_exp = exp;
1288   tree type = TREE_TYPE (exp);
1289   tree adr;
1290   tree restype = TREE_TYPE (type);
1291   tree ptrtype;
1292
1293   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1294
1295   STRIP_TYPE_NOPS (exp);
1296
1297   if (TREE_NO_WARNING (orig_exp))
1298     TREE_NO_WARNING (exp) = 1;
1299
1300   ptrtype = build_pointer_type (restype);
1301
1302   if (TREE_CODE (exp) == INDIRECT_REF)
1303     return convert (ptrtype, TREE_OPERAND (exp, 0));
1304
1305   if (TREE_CODE (exp) == VAR_DECL)
1306     {
1307       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1308          ADDR_EXPR because it's the best way of representing what
1309          happens in C when we take the address of an array and place
1310          it in a pointer to the element type.  */
1311       adr = build1 (ADDR_EXPR, ptrtype, exp);
1312       if (!c_mark_addressable (exp))
1313         return error_mark_node;
1314       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1315       return adr;
1316     }
1317
1318   /* This way is better for a COMPONENT_REF since it can
1319      simplify the offset for a component.  */
1320   adr = build_unary_op (ADDR_EXPR, exp, 1);
1321   return convert (ptrtype, adr);
1322 }
1323
1324 /* Convert the function expression EXP to a pointer.  */
1325 static tree
1326 function_to_pointer_conversion (tree exp)
1327 {
1328   tree orig_exp = exp;
1329
1330   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1331
1332   STRIP_TYPE_NOPS (exp);
1333
1334   if (TREE_NO_WARNING (orig_exp))
1335     TREE_NO_WARNING (exp) = 1;
1336
1337   return build_unary_op (ADDR_EXPR, exp, 0);
1338 }
1339
1340 /* Perform the default conversion of arrays and functions to pointers.
1341    Return the result of converting EXP.  For any other expression, just
1342    return EXP after removing NOPs.  */
1343
1344 struct c_expr
1345 default_function_array_conversion (struct c_expr exp)
1346 {
1347   tree orig_exp = exp.value;
1348   tree type = TREE_TYPE (exp.value);
1349   enum tree_code code = TREE_CODE (type);
1350
1351   switch (code)
1352     {
1353     case ARRAY_TYPE:
1354       {
1355         bool not_lvalue = false;
1356         bool lvalue_array_p;
1357
1358         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1359                 || TREE_CODE (exp.value) == NOP_EXPR)
1360                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1361           {
1362             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1363               not_lvalue = true;
1364             exp.value = TREE_OPERAND (exp.value, 0);
1365           }
1366
1367         if (TREE_NO_WARNING (orig_exp))
1368           TREE_NO_WARNING (exp.value) = 1;
1369
1370         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1371         if (!flag_isoc99 && !lvalue_array_p)
1372           {
1373             /* Before C99, non-lvalue arrays do not decay to pointers.
1374                Normally, using such an array would be invalid; but it can
1375                be used correctly inside sizeof or as a statement expression.
1376                Thus, do not give an error here; an error will result later.  */
1377             return exp;
1378           }
1379
1380         exp.value = array_to_pointer_conversion (exp.value);
1381       }
1382       break;
1383     case FUNCTION_TYPE:
1384       exp.value = function_to_pointer_conversion (exp.value);
1385       break;
1386     default:
1387       STRIP_TYPE_NOPS (exp.value);
1388       if (TREE_NO_WARNING (orig_exp))
1389         TREE_NO_WARNING (exp.value) = 1;
1390       break;
1391     }
1392
1393   return exp;
1394 }
1395
1396
1397 /* EXP is an expression of integer type.  Apply the integer promotions
1398    to it and return the promoted value.  */
1399
1400 tree
1401 perform_integral_promotions (tree exp)
1402 {
1403   tree type = TREE_TYPE (exp);
1404   enum tree_code code = TREE_CODE (type);
1405
1406   gcc_assert (INTEGRAL_TYPE_P (type));
1407
1408   /* Normally convert enums to int,
1409      but convert wide enums to something wider.  */
1410   if (code == ENUMERAL_TYPE)
1411     {
1412       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1413                                           TYPE_PRECISION (integer_type_node)),
1414                                      ((TYPE_PRECISION (type)
1415                                        >= TYPE_PRECISION (integer_type_node))
1416                                       && TYPE_UNSIGNED (type)));
1417
1418       return convert (type, exp);
1419     }
1420
1421   /* ??? This should no longer be needed now bit-fields have their
1422      proper types.  */
1423   if (TREE_CODE (exp) == COMPONENT_REF
1424       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1425       /* If it's thinner than an int, promote it like a
1426          c_promoting_integer_type_p, otherwise leave it alone.  */
1427       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1428                                TYPE_PRECISION (integer_type_node)))
1429     return convert (integer_type_node, exp);
1430
1431   if (c_promoting_integer_type_p (type))
1432     {
1433       /* Preserve unsignedness if not really getting any wider.  */
1434       if (TYPE_UNSIGNED (type)
1435           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1436         return convert (unsigned_type_node, exp);
1437
1438       return convert (integer_type_node, exp);
1439     }
1440
1441   return exp;
1442 }
1443
1444
1445 /* Perform default promotions for C data used in expressions.
1446    Enumeral types or short or char are converted to int.
1447    In addition, manifest constants symbols are replaced by their values.  */
1448
1449 tree
1450 default_conversion (tree exp)
1451 {
1452   tree orig_exp;
1453   tree type = TREE_TYPE (exp);
1454   enum tree_code code = TREE_CODE (type);
1455
1456   /* Functions and arrays have been converted during parsing.  */
1457   gcc_assert (code != FUNCTION_TYPE);
1458   if (code == ARRAY_TYPE)
1459     return exp;
1460
1461   /* Constants can be used directly unless they're not loadable.  */
1462   if (TREE_CODE (exp) == CONST_DECL)
1463     exp = DECL_INITIAL (exp);
1464
1465   /* Replace a nonvolatile const static variable with its value unless
1466      it is an array, in which case we must be sure that taking the
1467      address of the array produces consistent results.  */
1468   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1469     {
1470       exp = decl_constant_value_for_broken_optimization (exp);
1471       type = TREE_TYPE (exp);
1472     }
1473
1474   /* Strip no-op conversions.  */
1475   orig_exp = exp;
1476   STRIP_TYPE_NOPS (exp);
1477
1478   if (TREE_NO_WARNING (orig_exp))
1479     TREE_NO_WARNING (exp) = 1;
1480
1481   if (INTEGRAL_TYPE_P (type))
1482     return perform_integral_promotions (exp);
1483
1484   if (code == VOID_TYPE)
1485     {
1486       error ("void value not ignored as it ought to be");
1487       return error_mark_node;
1488     }
1489   return exp;
1490 }
1491 \f
1492 /* Look up COMPONENT in a structure or union DECL.
1493
1494    If the component name is not found, returns NULL_TREE.  Otherwise,
1495    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1496    stepping down the chain to the component, which is in the last
1497    TREE_VALUE of the list.  Normally the list is of length one, but if
1498    the component is embedded within (nested) anonymous structures or
1499    unions, the list steps down the chain to the component.  */
1500
1501 static tree
1502 lookup_field (tree decl, tree component)
1503 {
1504   tree type = TREE_TYPE (decl);
1505   tree field;
1506
1507   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1508      to the field elements.  Use a binary search on this array to quickly
1509      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1510      will always be set for structures which have many elements.  */
1511
1512   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1513     {
1514       int bot, top, half;
1515       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1516
1517       field = TYPE_FIELDS (type);
1518       bot = 0;
1519       top = TYPE_LANG_SPECIFIC (type)->s->len;
1520       while (top - bot > 1)
1521         {
1522           half = (top - bot + 1) >> 1;
1523           field = field_array[bot+half];
1524
1525           if (DECL_NAME (field) == NULL_TREE)
1526             {
1527               /* Step through all anon unions in linear fashion.  */
1528               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1529                 {
1530                   field = field_array[bot++];
1531                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1532                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1533                     {
1534                       tree anon = lookup_field (field, component);
1535
1536                       if (anon)
1537                         return tree_cons (NULL_TREE, field, anon);
1538                     }
1539                 }
1540
1541               /* Entire record is only anon unions.  */
1542               if (bot > top)
1543                 return NULL_TREE;
1544
1545               /* Restart the binary search, with new lower bound.  */
1546               continue;
1547             }
1548
1549           if (DECL_NAME (field) == component)
1550             break;
1551           if (DECL_NAME (field) < component)
1552             bot += half;
1553           else
1554             top = bot + half;
1555         }
1556
1557       if (DECL_NAME (field_array[bot]) == component)
1558         field = field_array[bot];
1559       else if (DECL_NAME (field) != component)
1560         return NULL_TREE;
1561     }
1562   else
1563     {
1564       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1565         {
1566           if (DECL_NAME (field) == NULL_TREE
1567               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1568                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1569             {
1570               tree anon = lookup_field (field, component);
1571
1572               if (anon)
1573                 return tree_cons (NULL_TREE, field, anon);
1574             }
1575
1576           if (DECL_NAME (field) == component)
1577             break;
1578         }
1579
1580       if (field == NULL_TREE)
1581         return NULL_TREE;
1582     }
1583
1584   return tree_cons (NULL_TREE, field, NULL_TREE);
1585 }
1586
1587 /* Make an expression to refer to the COMPONENT field of
1588    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1589
1590 tree
1591 build_component_ref (tree datum, tree component)
1592 {
1593   tree type = TREE_TYPE (datum);
1594   enum tree_code code = TREE_CODE (type);
1595   tree field = NULL;
1596   tree ref;
1597
1598   if (!objc_is_public (datum, component))
1599     return error_mark_node;
1600
1601   /* See if there is a field or component with name COMPONENT.  */
1602
1603   if (code == RECORD_TYPE || code == UNION_TYPE)
1604     {
1605       if (!COMPLETE_TYPE_P (type))
1606         {
1607           c_incomplete_type_error (NULL_TREE, type);
1608           return error_mark_node;
1609         }
1610
1611       field = lookup_field (datum, component);
1612
1613       if (!field)
1614         {
1615           error ("%qT has no member named %qE", type, component);
1616           return error_mark_node;
1617         }
1618
1619       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1620          This might be better solved in future the way the C++ front
1621          end does it - by giving the anonymous entities each a
1622          separate name and type, and then have build_component_ref
1623          recursively call itself.  We can't do that here.  */
1624       do
1625         {
1626           tree subdatum = TREE_VALUE (field);
1627
1628           if (TREE_TYPE (subdatum) == error_mark_node)
1629             return error_mark_node;
1630
1631           ref = build3 (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1632                         NULL_TREE);
1633           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1634             TREE_READONLY (ref) = 1;
1635           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1636             TREE_THIS_VOLATILE (ref) = 1;
1637
1638           if (TREE_DEPRECATED (subdatum))
1639             warn_deprecated_use (subdatum);
1640
1641           datum = ref;
1642
1643           field = TREE_CHAIN (field);
1644         }
1645       while (field);
1646
1647       return ref;
1648     }
1649   else if (code != ERROR_MARK)
1650     error ("request for member %qE in something not a structure or union",
1651            component);
1652
1653   return error_mark_node;
1654 }
1655 \f
1656 /* Given an expression PTR for a pointer, return an expression
1657    for the value pointed to.
1658    ERRORSTRING is the name of the operator to appear in error messages.  */
1659
1660 tree
1661 build_indirect_ref (tree ptr, const char *errorstring)
1662 {
1663   tree pointer = default_conversion (ptr);
1664   tree type = TREE_TYPE (pointer);
1665
1666   if (TREE_CODE (type) == POINTER_TYPE)
1667     {
1668       if (TREE_CODE (pointer) == ADDR_EXPR
1669           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1670               == TREE_TYPE (type)))
1671         return TREE_OPERAND (pointer, 0);
1672       else
1673         {
1674           tree t = TREE_TYPE (type);
1675           tree ref;
1676
1677           ref = build1 (INDIRECT_REF, t, pointer);
1678
1679           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1680             {
1681               error ("dereferencing pointer to incomplete type");
1682               return error_mark_node;
1683             }
1684           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1685             warning (0, "dereferencing %<void *%> pointer");
1686
1687           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1688              so that we get the proper error message if the result is used
1689              to assign to.  Also, &* is supposed to be a no-op.
1690              And ANSI C seems to specify that the type of the result
1691              should be the const type.  */
1692           /* A de-reference of a pointer to const is not a const.  It is valid
1693              to change it via some other pointer.  */
1694           TREE_READONLY (ref) = TYPE_READONLY (t);
1695           TREE_SIDE_EFFECTS (ref)
1696             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1697           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1698           return ref;
1699         }
1700     }
1701   else if (TREE_CODE (pointer) != ERROR_MARK)
1702     error ("invalid type argument of %qs", errorstring);
1703   return error_mark_node;
1704 }
1705
1706 /* This handles expressions of the form "a[i]", which denotes
1707    an array reference.
1708
1709    This is logically equivalent in C to *(a+i), but we may do it differently.
1710    If A is a variable or a member, we generate a primitive ARRAY_REF.
1711    This avoids forcing the array out of registers, and can work on
1712    arrays that are not lvalues (for example, members of structures returned
1713    by functions).  */
1714
1715 tree
1716 build_array_ref (tree array, tree index)
1717 {
1718   bool swapped = false;
1719   if (TREE_TYPE (array) == error_mark_node
1720       || TREE_TYPE (index) == error_mark_node)
1721     return error_mark_node;
1722
1723   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1724       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1725     {
1726       tree temp;
1727       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1728           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1729         {
1730           error ("subscripted value is neither array nor pointer");
1731           return error_mark_node;
1732         }
1733       temp = array;
1734       array = index;
1735       index = temp;
1736       swapped = true;
1737     }
1738
1739   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1740     {
1741       error ("array subscript is not an integer");
1742       return error_mark_node;
1743     }
1744
1745   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1746     {
1747       error ("subscripted value is pointer to function");
1748       return error_mark_node;
1749     }
1750
1751   /* Subscripting with type char is likely to lose on a machine where
1752      chars are signed.  So warn on any machine, but optionally.  Don't
1753      warn for unsigned char since that type is safe.  Don't warn for
1754      signed char because anyone who uses that must have done so
1755      deliberately.  ??? Existing practice has also been to warn only
1756      when the char index is syntactically the index, not for
1757      char[array].  */
1758   if (!swapped
1759       && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1760     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
1761
1762   /* Apply default promotions *after* noticing character types.  */
1763   index = default_conversion (index);
1764
1765   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1766
1767   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1768     {
1769       tree rval, type;
1770
1771       /* An array that is indexed by a non-constant
1772          cannot be stored in a register; we must be able to do
1773          address arithmetic on its address.
1774          Likewise an array of elements of variable size.  */
1775       if (TREE_CODE (index) != INTEGER_CST
1776           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1777               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1778         {
1779           if (!c_mark_addressable (array))
1780             return error_mark_node;
1781         }
1782       /* An array that is indexed by a constant value which is not within
1783          the array bounds cannot be stored in a register either; because we
1784          would get a crash in store_bit_field/extract_bit_field when trying
1785          to access a non-existent part of the register.  */
1786       if (TREE_CODE (index) == INTEGER_CST
1787           && TYPE_DOMAIN (TREE_TYPE (array))
1788           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1789         {
1790           if (!c_mark_addressable (array))
1791             return error_mark_node;
1792         }
1793
1794       if (pedantic)
1795         {
1796           tree foo = array;
1797           while (TREE_CODE (foo) == COMPONENT_REF)
1798             foo = TREE_OPERAND (foo, 0);
1799           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1800             pedwarn ("ISO C forbids subscripting %<register%> array");
1801           else if (!flag_isoc99 && !lvalue_p (foo))
1802             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1803         }
1804
1805       type = TREE_TYPE (TREE_TYPE (array));
1806       if (TREE_CODE (type) != ARRAY_TYPE)
1807         type = TYPE_MAIN_VARIANT (type);
1808       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1809       /* Array ref is const/volatile if the array elements are
1810          or if the array is.  */
1811       TREE_READONLY (rval)
1812         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1813             | TREE_READONLY (array));
1814       TREE_SIDE_EFFECTS (rval)
1815         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1816             | TREE_SIDE_EFFECTS (array));
1817       TREE_THIS_VOLATILE (rval)
1818         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1819             /* This was added by rms on 16 Nov 91.
1820                It fixes  vol struct foo *a;  a->elts[1]
1821                in an inline function.
1822                Hope it doesn't break something else.  */
1823             | TREE_THIS_VOLATILE (array));
1824       return require_complete_type (fold (rval));
1825     }
1826   else
1827     {
1828       tree ar = default_conversion (array);
1829
1830       if (ar == error_mark_node)
1831         return ar;
1832
1833       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1834       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1835
1836       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1837                                  "array indexing");
1838     }
1839 }
1840 \f
1841 /* Build an external reference to identifier ID.  FUN indicates
1842    whether this will be used for a function call.  LOC is the source
1843    location of the identifier.  */
1844 tree
1845 build_external_ref (tree id, int fun, location_t loc)
1846 {
1847   tree ref;
1848   tree decl = lookup_name (id);
1849
1850   /* In Objective-C, an instance variable (ivar) may be preferred to
1851      whatever lookup_name() found.  */
1852   decl = objc_lookup_ivar (decl, id);
1853
1854   if (decl && decl != error_mark_node)
1855     ref = decl;
1856   else if (fun)
1857     /* Implicit function declaration.  */
1858     ref = implicitly_declare (id);
1859   else if (decl == error_mark_node)
1860     /* Don't complain about something that's already been
1861        complained about.  */
1862     return error_mark_node;
1863   else
1864     {
1865       undeclared_variable (id, loc);
1866       return error_mark_node;
1867     }
1868
1869   if (TREE_TYPE (ref) == error_mark_node)
1870     return error_mark_node;
1871
1872   if (TREE_DEPRECATED (ref))
1873     warn_deprecated_use (ref);
1874
1875   if (!skip_evaluation)
1876     assemble_external (ref);
1877   TREE_USED (ref) = 1;
1878
1879   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
1880     {
1881       if (!in_sizeof && !in_typeof)
1882         C_DECL_USED (ref) = 1;
1883       else if (DECL_INITIAL (ref) == 0
1884                && DECL_EXTERNAL (ref)
1885                && !TREE_PUBLIC (ref))
1886         record_maybe_used_decl (ref);
1887     }
1888
1889   if (TREE_CODE (ref) == CONST_DECL)
1890     {
1891       ref = DECL_INITIAL (ref);
1892       TREE_CONSTANT (ref) = 1;
1893       TREE_INVARIANT (ref) = 1;
1894     }
1895   else if (current_function_decl != 0
1896            && !DECL_FILE_SCOPE_P (current_function_decl)
1897            && (TREE_CODE (ref) == VAR_DECL
1898                || TREE_CODE (ref) == PARM_DECL
1899                || TREE_CODE (ref) == FUNCTION_DECL))
1900     {
1901       tree context = decl_function_context (ref);
1902
1903       if (context != 0 && context != current_function_decl)
1904         DECL_NONLOCAL (ref) = 1;
1905     }
1906
1907   return ref;
1908 }
1909
1910 /* Record details of decls possibly used inside sizeof or typeof.  */
1911 struct maybe_used_decl
1912 {
1913   /* The decl.  */
1914   tree decl;
1915   /* The level seen at (in_sizeof + in_typeof).  */
1916   int level;
1917   /* The next one at this level or above, or NULL.  */
1918   struct maybe_used_decl *next;
1919 };
1920
1921 static struct maybe_used_decl *maybe_used_decls;
1922
1923 /* Record that DECL, an undefined static function reference seen
1924    inside sizeof or typeof, might be used if the operand of sizeof is
1925    a VLA type or the operand of typeof is a variably modified
1926    type.  */
1927
1928 static void
1929 record_maybe_used_decl (tree decl)
1930 {
1931   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
1932   t->decl = decl;
1933   t->level = in_sizeof + in_typeof;
1934   t->next = maybe_used_decls;
1935   maybe_used_decls = t;
1936 }
1937
1938 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
1939    USED is false, just discard them.  If it is true, mark them used
1940    (if no longer inside sizeof or typeof) or move them to the next
1941    level up (if still inside sizeof or typeof).  */
1942
1943 void
1944 pop_maybe_used (bool used)
1945 {
1946   struct maybe_used_decl *p = maybe_used_decls;
1947   int cur_level = in_sizeof + in_typeof;
1948   while (p && p->level > cur_level)
1949     {
1950       if (used)
1951         {
1952           if (cur_level == 0)
1953             C_DECL_USED (p->decl) = 1;
1954           else
1955             p->level = cur_level;
1956         }
1957       p = p->next;
1958     }
1959   if (!used || cur_level == 0)
1960     maybe_used_decls = p;
1961 }
1962
1963 /* Return the result of sizeof applied to EXPR.  */
1964
1965 struct c_expr
1966 c_expr_sizeof_expr (struct c_expr expr)
1967 {
1968   struct c_expr ret;
1969   if (expr.value == error_mark_node)
1970     {
1971       ret.value = error_mark_node;
1972       ret.original_code = ERROR_MARK;
1973       pop_maybe_used (false);
1974     }
1975   else
1976     {
1977       ret.value = c_sizeof (TREE_TYPE (expr.value));
1978       ret.original_code = ERROR_MARK;
1979       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
1980     }
1981   return ret;
1982 }
1983
1984 /* Return the result of sizeof applied to T, a structure for the type
1985    name passed to sizeof (rather than the type itself).  */
1986
1987 struct c_expr
1988 c_expr_sizeof_type (struct c_type_name *t)
1989 {
1990   tree type;
1991   struct c_expr ret;
1992   type = groktypename (t);
1993   ret.value = c_sizeof (type);
1994   ret.original_code = ERROR_MARK;
1995   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
1996   return ret;
1997 }
1998
1999 /* Build a function call to function FUNCTION with parameters PARAMS.
2000    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2001    TREE_VALUE of each node is a parameter-expression.
2002    FUNCTION's data type may be a function type or a pointer-to-function.  */
2003
2004 tree
2005 build_function_call (tree function, tree params)
2006 {
2007   tree fntype, fundecl = 0;
2008   tree coerced_params;
2009   tree name = NULL_TREE, result;
2010   tree tem;
2011
2012   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2013   STRIP_TYPE_NOPS (function);
2014
2015   /* Convert anything with function type to a pointer-to-function.  */
2016   if (TREE_CODE (function) == FUNCTION_DECL)
2017     {
2018       /* Implement type-directed function overloading for builtins.
2019          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2020          handle all the type checking.  The result is a complete expression
2021          that implements this function call.  */
2022       tem = resolve_overloaded_builtin (function, params);
2023       if (tem)
2024         return tem;
2025
2026       name = DECL_NAME (function);
2027       fundecl = function;
2028     }
2029   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2030     function = function_to_pointer_conversion (function);
2031
2032   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2033      expressions, like those used for ObjC messenger dispatches.  */
2034   function = objc_rewrite_function_call (function, params);
2035
2036   fntype = TREE_TYPE (function);
2037
2038   if (TREE_CODE (fntype) == ERROR_MARK)
2039     return error_mark_node;
2040
2041   if (!(TREE_CODE (fntype) == POINTER_TYPE
2042         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2043     {
2044       error ("called object %qE is not a function", function);
2045       return error_mark_node;
2046     }
2047
2048   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2049     current_function_returns_abnormally = 1;
2050
2051   /* fntype now gets the type of function pointed to.  */
2052   fntype = TREE_TYPE (fntype);
2053
2054   /* Check that the function is called through a compatible prototype.
2055      If it is not, replace the call by a trap, wrapped up in a compound
2056      expression if necessary.  This has the nice side-effect to prevent
2057      the tree-inliner from generating invalid assignment trees which may
2058      blow up in the RTL expander later.  */
2059   if (TREE_CODE (function) == NOP_EXPR
2060       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2061       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2062       && !comptypes (fntype, TREE_TYPE (tem)))
2063     {
2064       tree return_type = TREE_TYPE (fntype);
2065       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2066                                        NULL_TREE);
2067
2068       /* This situation leads to run-time undefined behavior.  We can't,
2069          therefore, simply error unless we can prove that all possible
2070          executions of the program must execute the code.  */
2071       warning (0, "function called through a non-compatible type");
2072
2073       /* We can, however, treat "undefined" any way we please.
2074          Call abort to encourage the user to fix the program.  */
2075       inform ("if this code is reached, the program will abort");
2076
2077       if (VOID_TYPE_P (return_type))
2078         return trap;
2079       else
2080         {
2081           tree rhs;
2082
2083           if (AGGREGATE_TYPE_P (return_type))
2084             rhs = build_compound_literal (return_type,
2085                                           build_constructor (return_type, 0));
2086           else
2087             rhs = fold_build1 (NOP_EXPR, return_type, integer_zero_node);
2088
2089           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2090         }
2091     }
2092
2093   /* Convert the parameters to the types declared in the
2094      function prototype, or apply default promotions.  */
2095
2096   coerced_params
2097     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2098
2099   if (coerced_params == error_mark_node)
2100     return error_mark_node;
2101
2102   /* Check that the arguments to the function are valid.  */
2103
2104   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2105                             TYPE_ARG_TYPES (fntype));
2106
2107   result = build3 (CALL_EXPR, TREE_TYPE (fntype),
2108                    function, coerced_params, NULL_TREE);
2109   TREE_SIDE_EFFECTS (result) = 1;
2110
2111   if (require_constant_value)
2112     {
2113       result = fold_initializer (result);
2114
2115       if (TREE_CONSTANT (result)
2116           && (name == NULL_TREE
2117               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2118         pedwarn_init ("initializer element is not constant");
2119     }
2120   else
2121     result = fold (result);
2122
2123   if (VOID_TYPE_P (TREE_TYPE (result)))
2124     return result;
2125   return require_complete_type (result);
2126 }
2127 \f
2128 /* Convert the argument expressions in the list VALUES
2129    to the types in the list TYPELIST.  The result is a list of converted
2130    argument expressions, unless there are too few arguments in which
2131    case it is error_mark_node.
2132
2133    If TYPELIST is exhausted, or when an element has NULL as its type,
2134    perform the default conversions.
2135
2136    PARMLIST is the chain of parm decls for the function being called.
2137    It may be 0, if that info is not available.
2138    It is used only for generating error messages.
2139
2140    FUNCTION is a tree for the called function.  It is used only for
2141    error messages, where it is formatted with %qE.
2142
2143    This is also where warnings about wrong number of args are generated.
2144
2145    Both VALUES and the returned value are chains of TREE_LIST nodes
2146    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2147
2148 static tree
2149 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2150 {
2151   tree typetail, valtail;
2152   tree result = NULL;
2153   int parmnum;
2154   tree selector;
2155
2156   /* Change pointer to function to the function itself for
2157      diagnostics.  */
2158   if (TREE_CODE (function) == ADDR_EXPR
2159       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2160     function = TREE_OPERAND (function, 0);
2161
2162   /* Handle an ObjC selector specially for diagnostics.  */
2163   selector = objc_message_selector ();
2164
2165   /* Scan the given expressions and types, producing individual
2166      converted arguments and pushing them on RESULT in reverse order.  */
2167
2168   for (valtail = values, typetail = typelist, parmnum = 0;
2169        valtail;
2170        valtail = TREE_CHAIN (valtail), parmnum++)
2171     {
2172       tree type = typetail ? TREE_VALUE (typetail) : 0;
2173       tree val = TREE_VALUE (valtail);
2174       tree rname = function;
2175       int argnum = parmnum + 1;
2176       const char *invalid_func_diag;
2177
2178       if (type == void_type_node)
2179         {
2180           error ("too many arguments to function %qE", function);
2181           break;
2182         }
2183
2184       if (selector && argnum > 2)
2185         {
2186           rname = selector;
2187           argnum -= 2;
2188         }
2189
2190       STRIP_TYPE_NOPS (val);
2191
2192       val = require_complete_type (val);
2193
2194       if (type != 0)
2195         {
2196           /* Formal parm type is specified by a function prototype.  */
2197           tree parmval;
2198
2199           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2200             {
2201               error ("type of formal parameter %d is incomplete", parmnum + 1);
2202               parmval = val;
2203             }
2204           else
2205             {
2206               /* Optionally warn about conversions that
2207                  differ from the default conversions.  */
2208               if (warn_conversion || warn_traditional)
2209                 {
2210                   unsigned int formal_prec = TYPE_PRECISION (type);
2211
2212                   if (INTEGRAL_TYPE_P (type)
2213                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2214                     warning (0, "passing argument %d of %qE as integer "
2215                              "rather than floating due to prototype",
2216                              argnum, rname);
2217                   if (INTEGRAL_TYPE_P (type)
2218                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2219                     warning (0, "passing argument %d of %qE as integer "
2220                              "rather than complex due to prototype",
2221                              argnum, rname);
2222                   else if (TREE_CODE (type) == COMPLEX_TYPE
2223                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2224                     warning (0, "passing argument %d of %qE as complex "
2225                              "rather than floating due to prototype",
2226                              argnum, rname);
2227                   else if (TREE_CODE (type) == REAL_TYPE
2228                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2229                     warning (0, "passing argument %d of %qE as floating "
2230                              "rather than integer due to prototype",
2231                              argnum, rname);
2232                   else if (TREE_CODE (type) == COMPLEX_TYPE
2233                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2234                     warning (0, "passing argument %d of %qE as complex "
2235                              "rather than integer due to prototype",
2236                              argnum, rname);
2237                   else if (TREE_CODE (type) == REAL_TYPE
2238                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2239                     warning (0, "passing argument %d of %qE as floating "
2240                              "rather than complex due to prototype",
2241                              argnum, rname);
2242                   /* ??? At some point, messages should be written about
2243                      conversions between complex types, but that's too messy
2244                      to do now.  */
2245                   else if (TREE_CODE (type) == REAL_TYPE
2246                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2247                     {
2248                       /* Warn if any argument is passed as `float',
2249                          since without a prototype it would be `double'.  */
2250                       if (formal_prec == TYPE_PRECISION (float_type_node))
2251                         warning (0, "passing argument %d of %qE as %<float%> "
2252                                  "rather than %<double%> due to prototype",
2253                                  argnum, rname);
2254                     }
2255                   /* Detect integer changing in width or signedness.
2256                      These warnings are only activated with
2257                      -Wconversion, not with -Wtraditional.  */
2258                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2259                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2260                     {
2261                       tree would_have_been = default_conversion (val);
2262                       tree type1 = TREE_TYPE (would_have_been);
2263
2264                       if (TREE_CODE (type) == ENUMERAL_TYPE
2265                           && (TYPE_MAIN_VARIANT (type)
2266                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2267                         /* No warning if function asks for enum
2268                            and the actual arg is that enum type.  */
2269                         ;
2270                       else if (formal_prec != TYPE_PRECISION (type1))
2271                         warning (OPT_Wconversion, "passing argument %d of %qE "
2272                                  "with different width due to prototype",
2273                                  argnum, rname);
2274                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2275                         ;
2276                       /* Don't complain if the formal parameter type
2277                          is an enum, because we can't tell now whether
2278                          the value was an enum--even the same enum.  */
2279                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2280                         ;
2281                       else if (TREE_CODE (val) == INTEGER_CST
2282                                && int_fits_type_p (val, type))
2283                         /* Change in signedness doesn't matter
2284                            if a constant value is unaffected.  */
2285                         ;
2286                       /* If the value is extended from a narrower
2287                          unsigned type, it doesn't matter whether we
2288                          pass it as signed or unsigned; the value
2289                          certainly is the same either way.  */
2290                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2291                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2292                         ;
2293                       else if (TYPE_UNSIGNED (type))
2294                         warning (OPT_Wconversion, "passing argument %d of %qE "
2295                                  "as unsigned due to prototype",
2296                                  argnum, rname);
2297                       else
2298                         warning (OPT_Wconversion, "passing argument %d of %qE "
2299                                  "as signed due to prototype", argnum, rname);
2300                     }
2301                 }
2302
2303               parmval = convert_for_assignment (type, val, ic_argpass,
2304                                                 fundecl, function,
2305                                                 parmnum + 1);
2306
2307               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2308                   && INTEGRAL_TYPE_P (type)
2309                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2310                 parmval = default_conversion (parmval);
2311             }
2312           result = tree_cons (NULL_TREE, parmval, result);
2313         }
2314       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2315                && (TYPE_PRECISION (TREE_TYPE (val))
2316                    < TYPE_PRECISION (double_type_node)))
2317         /* Convert `float' to `double'.  */
2318         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2319       else if ((invalid_func_diag =
2320                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2321         {
2322           error (invalid_func_diag);
2323           return error_mark_node;
2324         }
2325       else
2326         /* Convert `short' and `char' to full-size `int'.  */
2327         result = tree_cons (NULL_TREE, default_conversion (val), result);
2328
2329       if (typetail)
2330         typetail = TREE_CHAIN (typetail);
2331     }
2332
2333   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2334     {
2335       error ("too few arguments to function %qE", function);
2336       return error_mark_node;
2337     }
2338
2339   return nreverse (result);
2340 }
2341 \f
2342 /* This is the entry point used by the parser to build unary operators
2343    in the input.  CODE, a tree_code, specifies the unary operator, and
2344    ARG is the operand.  For unary plus, the C parser currently uses
2345    CONVERT_EXPR for code.  */
2346
2347 struct c_expr
2348 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2349 {
2350   struct c_expr result;
2351
2352   result.original_code = ERROR_MARK;
2353   result.value = build_unary_op (code, arg.value, 0);
2354   overflow_warning (result.value);
2355   return result;
2356 }
2357
2358 /* This is the entry point used by the parser to build binary operators
2359    in the input.  CODE, a tree_code, specifies the binary operator, and
2360    ARG1 and ARG2 are the operands.  In addition to constructing the
2361    expression, we check for operands that were written with other binary
2362    operators in a way that is likely to confuse the user.  */
2363
2364 struct c_expr
2365 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2366                         struct c_expr arg2)
2367 {
2368   struct c_expr result;
2369
2370   enum tree_code code1 = arg1.original_code;
2371   enum tree_code code2 = arg2.original_code;
2372
2373   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2374   result.original_code = code;
2375
2376   if (TREE_CODE (result.value) == ERROR_MARK)
2377     return result;
2378
2379   /* Check for cases such as x+y<<z which users are likely
2380      to misinterpret.  */
2381   if (warn_parentheses)
2382     {
2383       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2384         {
2385           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2386               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2387             warning (OPT_Wparentheses,
2388                      "suggest parentheses around + or - inside shift");
2389         }
2390
2391       if (code == TRUTH_ORIF_EXPR)
2392         {
2393           if (code1 == TRUTH_ANDIF_EXPR
2394               || code2 == TRUTH_ANDIF_EXPR)
2395             warning (OPT_Wparentheses,
2396                      "suggest parentheses around && within ||");
2397         }
2398
2399       if (code == BIT_IOR_EXPR)
2400         {
2401           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2402               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2403               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2404               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2405             warning (OPT_Wparentheses,
2406                      "suggest parentheses around arithmetic in operand of |");
2407           /* Check cases like x|y==z */
2408           if (TREE_CODE_CLASS (code1) == tcc_comparison
2409               || TREE_CODE_CLASS (code2) == tcc_comparison)
2410             warning (OPT_Wparentheses,
2411                      "suggest parentheses around comparison in operand of |");
2412         }
2413
2414       if (code == BIT_XOR_EXPR)
2415         {
2416           if (code1 == BIT_AND_EXPR
2417               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2418               || code2 == BIT_AND_EXPR
2419               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2420             warning (OPT_Wparentheses,
2421                      "suggest parentheses around arithmetic in operand of ^");
2422           /* Check cases like x^y==z */
2423           if (TREE_CODE_CLASS (code1) == tcc_comparison
2424               || TREE_CODE_CLASS (code2) == tcc_comparison)
2425             warning (OPT_Wparentheses,
2426                      "suggest parentheses around comparison in operand of ^");
2427         }
2428
2429       if (code == BIT_AND_EXPR)
2430         {
2431           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2432               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2433             warning (OPT_Wparentheses,
2434                      "suggest parentheses around + or - in operand of &");
2435           /* Check cases like x&y==z */
2436           if (TREE_CODE_CLASS (code1) == tcc_comparison
2437               || TREE_CODE_CLASS (code2) == tcc_comparison)
2438             warning (OPT_Wparentheses,
2439                      "suggest parentheses around comparison in operand of &");
2440         }
2441       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2442       if (TREE_CODE_CLASS (code) == tcc_comparison
2443           && (TREE_CODE_CLASS (code1) == tcc_comparison
2444               || TREE_CODE_CLASS (code2) == tcc_comparison))
2445         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
2446                  "have their mathematical meaning");
2447
2448     }
2449
2450   unsigned_conversion_warning (result.value, arg1.value);
2451   unsigned_conversion_warning (result.value, arg2.value);
2452   overflow_warning (result.value);
2453
2454   return result;
2455 }
2456 \f
2457 /* Return a tree for the difference of pointers OP0 and OP1.
2458    The resulting tree has type int.  */
2459
2460 static tree
2461 pointer_diff (tree op0, tree op1)
2462 {
2463   tree restype = ptrdiff_type_node;
2464
2465   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2466   tree con0, con1, lit0, lit1;
2467   tree orig_op1 = op1;
2468
2469   if (pedantic || warn_pointer_arith)
2470     {
2471       if (TREE_CODE (target_type) == VOID_TYPE)
2472         pedwarn ("pointer of type %<void *%> used in subtraction");
2473       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2474         pedwarn ("pointer to a function used in subtraction");
2475     }
2476
2477   /* If the conversion to ptrdiff_type does anything like widening or
2478      converting a partial to an integral mode, we get a convert_expression
2479      that is in the way to do any simplifications.
2480      (fold-const.c doesn't know that the extra bits won't be needed.
2481      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2482      different mode in place.)
2483      So first try to find a common term here 'by hand'; we want to cover
2484      at least the cases that occur in legal static initializers.  */
2485   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2486   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2487
2488   if (TREE_CODE (con0) == PLUS_EXPR)
2489     {
2490       lit0 = TREE_OPERAND (con0, 1);
2491       con0 = TREE_OPERAND (con0, 0);
2492     }
2493   else
2494     lit0 = integer_zero_node;
2495
2496   if (TREE_CODE (con1) == PLUS_EXPR)
2497     {
2498       lit1 = TREE_OPERAND (con1, 1);
2499       con1 = TREE_OPERAND (con1, 0);
2500     }
2501   else
2502     lit1 = integer_zero_node;
2503
2504   if (operand_equal_p (con0, con1, 0))
2505     {
2506       op0 = lit0;
2507       op1 = lit1;
2508     }
2509
2510
2511   /* First do the subtraction as integers;
2512      then drop through to build the divide operator.
2513      Do not do default conversions on the minus operator
2514      in case restype is a short type.  */
2515
2516   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2517                          convert (restype, op1), 0);
2518   /* This generates an error if op1 is pointer to incomplete type.  */
2519   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2520     error ("arithmetic on pointer to an incomplete type");
2521
2522   /* This generates an error if op0 is pointer to incomplete type.  */
2523   op1 = c_size_in_bytes (target_type);
2524
2525   /* Divide by the size, in easiest possible way.  */
2526   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2527 }
2528 \f
2529 /* Construct and perhaps optimize a tree representation
2530    for a unary operation.  CODE, a tree_code, specifies the operation
2531    and XARG is the operand.
2532    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2533    the default promotions (such as from short to int).
2534    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2535    allows non-lvalues; this is only used to handle conversion of non-lvalue
2536    arrays to pointers in C99.  */
2537
2538 tree
2539 build_unary_op (enum tree_code code, tree xarg, int flag)
2540 {
2541   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2542   tree arg = xarg;
2543   tree argtype = 0;
2544   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2545   tree val;
2546   int noconvert = flag;
2547   const char *invalid_op_diag;
2548
2549   if (typecode == ERROR_MARK)
2550     return error_mark_node;
2551   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2552     typecode = INTEGER_TYPE;
2553
2554   if ((invalid_op_diag
2555        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2556     {
2557       error (invalid_op_diag);
2558       return error_mark_node;
2559     }
2560
2561   switch (code)
2562     {
2563     case CONVERT_EXPR:
2564       /* This is used for unary plus, because a CONVERT_EXPR
2565          is enough to prevent anybody from looking inside for
2566          associativity, but won't generate any code.  */
2567       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2568             || typecode == COMPLEX_TYPE
2569             || typecode == VECTOR_TYPE))
2570         {
2571           error ("wrong type argument to unary plus");
2572           return error_mark_node;
2573         }
2574       else if (!noconvert)
2575         arg = default_conversion (arg);
2576       arg = non_lvalue (arg);
2577       break;
2578
2579     case NEGATE_EXPR:
2580       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2581             || typecode == COMPLEX_TYPE
2582             || typecode == VECTOR_TYPE))
2583         {
2584           error ("wrong type argument to unary minus");
2585           return error_mark_node;
2586         }
2587       else if (!noconvert)
2588         arg = default_conversion (arg);
2589       break;
2590
2591     case BIT_NOT_EXPR:
2592       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2593         {
2594           if (!noconvert)
2595             arg = default_conversion (arg);
2596         }
2597       else if (typecode == COMPLEX_TYPE)
2598         {
2599           code = CONJ_EXPR;
2600           if (pedantic)
2601             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2602           if (!noconvert)
2603             arg = default_conversion (arg);
2604         }
2605       else
2606         {
2607           error ("wrong type argument to bit-complement");
2608           return error_mark_node;
2609         }
2610       break;
2611
2612     case ABS_EXPR:
2613       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2614         {
2615           error ("wrong type argument to abs");
2616           return error_mark_node;
2617         }
2618       else if (!noconvert)
2619         arg = default_conversion (arg);
2620       break;
2621
2622     case CONJ_EXPR:
2623       /* Conjugating a real value is a no-op, but allow it anyway.  */
2624       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2625             || typecode == COMPLEX_TYPE))
2626         {
2627           error ("wrong type argument to conjugation");
2628           return error_mark_node;
2629         }
2630       else if (!noconvert)
2631         arg = default_conversion (arg);
2632       break;
2633
2634     case TRUTH_NOT_EXPR:
2635       if (typecode != INTEGER_TYPE
2636           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2637           && typecode != COMPLEX_TYPE)
2638         {
2639           error ("wrong type argument to unary exclamation mark");
2640           return error_mark_node;
2641         }
2642       arg = c_objc_common_truthvalue_conversion (arg);
2643       return invert_truthvalue (arg);
2644
2645     case NOP_EXPR:
2646       break;
2647
2648     case REALPART_EXPR:
2649       if (TREE_CODE (arg) == COMPLEX_CST)
2650         return TREE_REALPART (arg);
2651       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2652         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2653       else
2654         return arg;
2655
2656     case IMAGPART_EXPR:
2657       if (TREE_CODE (arg) == COMPLEX_CST)
2658         return TREE_IMAGPART (arg);
2659       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2660         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2661       else
2662         return convert (TREE_TYPE (arg), integer_zero_node);
2663
2664     case PREINCREMENT_EXPR:
2665     case POSTINCREMENT_EXPR:
2666     case PREDECREMENT_EXPR:
2667     case POSTDECREMENT_EXPR:
2668
2669       /* Increment or decrement the real part of the value,
2670          and don't change the imaginary part.  */
2671       if (typecode == COMPLEX_TYPE)
2672         {
2673           tree real, imag;
2674
2675           if (pedantic)
2676             pedwarn ("ISO C does not support %<++%> and %<--%>"
2677                      " on complex types");
2678
2679           arg = stabilize_reference (arg);
2680           real = build_unary_op (REALPART_EXPR, arg, 1);
2681           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2682           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2683                          build_unary_op (code, real, 1), imag);
2684         }
2685
2686       /* Report invalid types.  */
2687
2688       if (typecode != POINTER_TYPE
2689           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2690         {
2691           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2692             error ("wrong type argument to increment");
2693           else
2694             error ("wrong type argument to decrement");
2695
2696           return error_mark_node;
2697         }
2698
2699       {
2700         tree inc;
2701         tree result_type = TREE_TYPE (arg);
2702
2703         arg = get_unwidened (arg, 0);
2704         argtype = TREE_TYPE (arg);
2705
2706         /* Compute the increment.  */
2707
2708         if (typecode == POINTER_TYPE)
2709           {
2710             /* If pointer target is an undefined struct,
2711                we just cannot know how to do the arithmetic.  */
2712             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2713               {
2714                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2715                   error ("increment of pointer to unknown structure");
2716                 else
2717                   error ("decrement of pointer to unknown structure");
2718               }
2719             else if ((pedantic || warn_pointer_arith)
2720                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2721                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2722               {
2723                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2724                   pedwarn ("wrong type argument to increment");
2725                 else
2726                   pedwarn ("wrong type argument to decrement");
2727               }
2728
2729             inc = c_size_in_bytes (TREE_TYPE (result_type));
2730           }
2731         else
2732           inc = integer_one_node;
2733
2734         inc = convert (argtype, inc);
2735
2736         /* Complain about anything else that is not a true lvalue.  */
2737         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2738                                     || code == POSTINCREMENT_EXPR)
2739                                    ? lv_increment
2740                                    : lv_decrement)))
2741           return error_mark_node;
2742
2743         /* Report a read-only lvalue.  */
2744         if (TREE_READONLY (arg))
2745           readonly_error (arg,
2746                           ((code == PREINCREMENT_EXPR
2747                             || code == POSTINCREMENT_EXPR)
2748                            ? lv_increment : lv_decrement));
2749
2750         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2751           val = boolean_increment (code, arg);
2752         else
2753           val = build2 (code, TREE_TYPE (arg), arg, inc);
2754         TREE_SIDE_EFFECTS (val) = 1;
2755         val = convert (result_type, val);
2756         if (TREE_CODE (val) != code)
2757           TREE_NO_WARNING (val) = 1;
2758         return val;
2759       }
2760
2761     case ADDR_EXPR:
2762       /* Note that this operation never does default_conversion.  */
2763
2764       /* Let &* cancel out to simplify resulting code.  */
2765       if (TREE_CODE (arg) == INDIRECT_REF)
2766         {
2767           /* Don't let this be an lvalue.  */
2768           if (lvalue_p (TREE_OPERAND (arg, 0)))
2769             return non_lvalue (TREE_OPERAND (arg, 0));
2770           return TREE_OPERAND (arg, 0);
2771         }
2772
2773       /* For &x[y], return x+y */
2774       if (TREE_CODE (arg) == ARRAY_REF)
2775         {
2776           tree op0 = TREE_OPERAND (arg, 0);
2777           if (!c_mark_addressable (op0))
2778             return error_mark_node;
2779           return build_binary_op (PLUS_EXPR,
2780                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2781                                    ? array_to_pointer_conversion (op0)
2782                                    : op0),
2783                                   TREE_OPERAND (arg, 1), 1);
2784         }
2785
2786       /* Anything not already handled and not a true memory reference
2787          or a non-lvalue array is an error.  */
2788       else if (typecode != FUNCTION_TYPE && !flag
2789                && !lvalue_or_else (arg, lv_addressof))
2790         return error_mark_node;
2791
2792       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2793       argtype = TREE_TYPE (arg);
2794
2795       /* If the lvalue is const or volatile, merge that into the type
2796          to which the address will point.  Note that you can't get a
2797          restricted pointer by taking the address of something, so we
2798          only have to deal with `const' and `volatile' here.  */
2799       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2800           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2801           argtype = c_build_type_variant (argtype,
2802                                           TREE_READONLY (arg),
2803                                           TREE_THIS_VOLATILE (arg));
2804
2805       if (!c_mark_addressable (arg))
2806         return error_mark_node;
2807
2808       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2809                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2810
2811       argtype = build_pointer_type (argtype);
2812
2813       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2814          when we have proper support for integer constant expressions.  */
2815       val = get_base_address (arg);
2816       if (val && TREE_CODE (val) == INDIRECT_REF
2817           && integer_zerop (TREE_OPERAND (val, 0)))
2818         return fold_convert (argtype, fold_offsetof (arg));
2819
2820       val = build1 (ADDR_EXPR, argtype, arg);
2821
2822       return val;
2823
2824     default:
2825       break;
2826     }
2827
2828   if (argtype == 0)
2829     argtype = TREE_TYPE (arg);
2830   val = build1 (code, argtype, arg);
2831   return require_constant_value ? fold_initializer (val) : fold (val);
2832 }
2833
2834 /* Return nonzero if REF is an lvalue valid for this language.
2835    Lvalues can be assigned, unless their type has TYPE_READONLY.
2836    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2837
2838 static int
2839 lvalue_p (tree ref)
2840 {
2841   enum tree_code code = TREE_CODE (ref);
2842
2843   switch (code)
2844     {
2845     case REALPART_EXPR:
2846     case IMAGPART_EXPR:
2847     case COMPONENT_REF:
2848       return lvalue_p (TREE_OPERAND (ref, 0));
2849
2850     case COMPOUND_LITERAL_EXPR:
2851     case STRING_CST:
2852       return 1;
2853
2854     case INDIRECT_REF:
2855     case ARRAY_REF:
2856     case VAR_DECL:
2857     case PARM_DECL:
2858     case RESULT_DECL:
2859     case ERROR_MARK:
2860       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2861               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2862
2863     case BIND_EXPR:
2864       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2865
2866     default:
2867       return 0;
2868     }
2869 }
2870 \f
2871 /* Give an error for storing in something that is 'const'.  */
2872
2873 static void
2874 readonly_error (tree arg, enum lvalue_use use)
2875 {
2876   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement);
2877   /* Using this macro rather than (for example) arrays of messages
2878      ensures that all the format strings are checked at compile
2879      time.  */
2880 #define READONLY_MSG(A, I, D) (use == lv_assign                         \
2881                                ? (A)                                    \
2882                                : (use == lv_increment ? (I) : (D)))
2883   if (TREE_CODE (arg) == COMPONENT_REF)
2884     {
2885       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2886         readonly_error (TREE_OPERAND (arg, 0), use);
2887       else
2888         error (READONLY_MSG (G_("assignment of read-only member %qD"),
2889                              G_("increment of read-only member %qD"),
2890                              G_("decrement of read-only member %qD")),
2891                TREE_OPERAND (arg, 1));
2892     }
2893   else if (TREE_CODE (arg) == VAR_DECL)
2894     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
2895                          G_("increment of read-only variable %qD"),
2896                          G_("decrement of read-only variable %qD")),
2897            arg);
2898   else
2899     error (READONLY_MSG (G_("assignment of read-only location"),
2900                          G_("increment of read-only location"),
2901                          G_("decrement of read-only location")));
2902 }
2903
2904
2905 /* Return nonzero if REF is an lvalue valid for this language;
2906    otherwise, print an error message and return zero.  USE says
2907    how the lvalue is being used and so selects the error message.  */
2908
2909 static int
2910 lvalue_or_else (tree ref, enum lvalue_use use)
2911 {
2912   int win = lvalue_p (ref);
2913
2914   if (!win)
2915     lvalue_error (use);
2916
2917   return win;
2918 }
2919 \f
2920 /* Mark EXP saying that we need to be able to take the
2921    address of it; it should not be allocated in a register.
2922    Returns true if successful.  */
2923
2924 bool
2925 c_mark_addressable (tree exp)
2926 {
2927   tree x = exp;
2928
2929   while (1)
2930     switch (TREE_CODE (x))
2931       {
2932       case COMPONENT_REF:
2933         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2934           {
2935             error
2936               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
2937             return false;
2938           }
2939
2940         /* ... fall through ...  */
2941
2942       case ADDR_EXPR:
2943       case ARRAY_REF:
2944       case REALPART_EXPR:
2945       case IMAGPART_EXPR:
2946         x = TREE_OPERAND (x, 0);
2947         break;
2948
2949       case COMPOUND_LITERAL_EXPR:
2950       case CONSTRUCTOR:
2951         TREE_ADDRESSABLE (x) = 1;
2952         return true;
2953
2954       case VAR_DECL:
2955       case CONST_DECL:
2956       case PARM_DECL:
2957       case RESULT_DECL:
2958         if (C_DECL_REGISTER (x)
2959             && DECL_NONLOCAL (x))
2960           {
2961             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2962               {
2963                 error
2964                   ("global register variable %qD used in nested function", x);
2965                 return false;
2966               }
2967             pedwarn ("register variable %qD used in nested function", x);
2968           }
2969         else if (C_DECL_REGISTER (x))
2970           {
2971             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2972               error ("address of global register variable %qD requested", x);
2973             else
2974               error ("address of register variable %qD requested", x);
2975             return false;
2976           }
2977
2978         /* drops in */
2979       case FUNCTION_DECL:
2980         TREE_ADDRESSABLE (x) = 1;
2981         /* drops out */
2982       default:
2983         return true;
2984     }
2985 }
2986 \f
2987 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2988
2989 tree
2990 build_conditional_expr (tree ifexp, tree op1, tree op2)
2991 {
2992   tree type1;
2993   tree type2;
2994   enum tree_code code1;
2995   enum tree_code code2;
2996   tree result_type = NULL;
2997   tree orig_op1 = op1, orig_op2 = op2;
2998
2999   /* Promote both alternatives.  */
3000
3001   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3002     op1 = default_conversion (op1);
3003   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3004     op2 = default_conversion (op2);
3005
3006   if (TREE_CODE (ifexp) == ERROR_MARK
3007       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3008       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3009     return error_mark_node;
3010
3011   type1 = TREE_TYPE (op1);
3012   code1 = TREE_CODE (type1);
3013   type2 = TREE_TYPE (op2);
3014   code2 = TREE_CODE (type2);
3015
3016   /* C90 does not permit non-lvalue arrays in conditional expressions.
3017      In C99 they will be pointers by now.  */
3018   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3019     {
3020       error ("non-lvalue array in conditional expression");
3021       return error_mark_node;
3022     }
3023
3024   /* Quickly detect the usual case where op1 and op2 have the same type
3025      after promotion.  */
3026   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3027     {
3028       if (type1 == type2)
3029         result_type = type1;
3030       else
3031         result_type = TYPE_MAIN_VARIANT (type1);
3032     }
3033   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3034             || code1 == COMPLEX_TYPE)
3035            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3036                || code2 == COMPLEX_TYPE))
3037     {
3038       result_type = c_common_type (type1, type2);
3039
3040       /* If -Wsign-compare, warn here if type1 and type2 have
3041          different signedness.  We'll promote the signed to unsigned
3042          and later code won't know it used to be different.
3043          Do this check on the original types, so that explicit casts
3044          will be considered, but default promotions won't.  */
3045       if (warn_sign_compare && !skip_evaluation)
3046         {
3047           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3048           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3049
3050           if (unsigned_op1 ^ unsigned_op2)
3051             {
3052               /* Do not warn if the result type is signed, since the
3053                  signed type will only be chosen if it can represent
3054                  all the values of the unsigned type.  */
3055               if (!TYPE_UNSIGNED (result_type))
3056                 /* OK */;
3057               /* Do not warn if the signed quantity is an unsuffixed
3058                  integer literal (or some static constant expression
3059                  involving such literals) and it is non-negative.  */
3060               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3061                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3062                 /* OK */;
3063               else
3064                 warning (0, "signed and unsigned type in conditional expression");
3065             }
3066         }
3067     }
3068   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3069     {
3070       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3071         pedwarn ("ISO C forbids conditional expr with only one void side");
3072       result_type = void_type_node;
3073     }
3074   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3075     {
3076       if (comp_target_types (type1, type2))
3077         result_type = common_pointer_type (type1, type2);
3078       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3079                && TREE_CODE (orig_op1) != NOP_EXPR)
3080         result_type = qualify_type (type2, type1);
3081       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3082                && TREE_CODE (orig_op2) != NOP_EXPR)
3083         result_type = qualify_type (type1, type2);
3084       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3085         {
3086           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3087             pedwarn ("ISO C forbids conditional expr between "
3088                      "%<void *%> and function pointer");
3089           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3090                                                           TREE_TYPE (type2)));
3091         }
3092       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3093         {
3094           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3095             pedwarn ("ISO C forbids conditional expr between "
3096                      "%<void *%> and function pointer");
3097           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3098                                                           TREE_TYPE (type1)));
3099         }
3100       else
3101         {
3102           pedwarn ("pointer type mismatch in conditional expression");
3103           result_type = build_pointer_type (void_type_node);
3104         }
3105     }
3106   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3107     {
3108       if (!integer_zerop (op2))
3109         pedwarn ("pointer/integer type mismatch in conditional expression");
3110       else
3111         {
3112           op2 = null_pointer_node;
3113         }
3114       result_type = type1;
3115     }
3116   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3117     {
3118       if (!integer_zerop (op1))
3119         pedwarn ("pointer/integer type mismatch in conditional expression");
3120       else
3121         {
3122           op1 = null_pointer_node;
3123         }
3124       result_type = type2;
3125     }
3126
3127   if (!result_type)
3128     {
3129       if (flag_cond_mismatch)
3130         result_type = void_type_node;
3131       else
3132         {
3133           error ("type mismatch in conditional expression");
3134           return error_mark_node;
3135         }
3136     }
3137
3138   /* Merge const and volatile flags of the incoming types.  */
3139   result_type
3140     = build_type_variant (result_type,
3141                           TREE_READONLY (op1) || TREE_READONLY (op2),
3142                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3143
3144   if (result_type != TREE_TYPE (op1))
3145     op1 = convert_and_check (result_type, op1);
3146   if (result_type != TREE_TYPE (op2))
3147     op2 = convert_and_check (result_type, op2);
3148
3149   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3150 }
3151 \f
3152 /* Return a compound expression that performs two expressions and
3153    returns the value of the second of them.  */
3154
3155 tree
3156 build_compound_expr (tree expr1, tree expr2)
3157 {
3158   if (!TREE_SIDE_EFFECTS (expr1))
3159     {
3160       /* The left-hand operand of a comma expression is like an expression
3161          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3162          any side-effects, unless it was explicitly cast to (void).  */
3163       if (warn_unused_value)
3164         {
3165           if (VOID_TYPE_P (TREE_TYPE (expr1))
3166               && TREE_CODE (expr1) == CONVERT_EXPR)
3167             ; /* (void) a, b */
3168           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3169                    && TREE_CODE (expr1) == COMPOUND_EXPR
3170                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3171             ; /* (void) a, (void) b, c */
3172           else
3173             warning (0, "left-hand operand of comma expression has no effect");
3174         }
3175     }
3176
3177   /* With -Wunused, we should also warn if the left-hand operand does have
3178      side-effects, but computes a value which is not used.  For example, in
3179      `foo() + bar(), baz()' the result of the `+' operator is not used,
3180      so we should issue a warning.  */
3181   else if (warn_unused_value)
3182     warn_if_unused_value (expr1, input_location);
3183
3184   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3185 }
3186
3187 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3188
3189 tree
3190 build_c_cast (tree type, tree expr)
3191 {
3192   tree value = expr;
3193
3194   if (type == error_mark_node || expr == error_mark_node)
3195     return error_mark_node;
3196
3197   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3198      only in <protocol> qualifications.  But when constructing cast expressions,
3199      the protocols do matter and must be kept around.  */
3200   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3201     return build1 (NOP_EXPR, type, expr);
3202
3203   type = TYPE_MAIN_VARIANT (type);
3204
3205   if (TREE_CODE (type) == ARRAY_TYPE)
3206     {
3207       error ("cast specifies array type");
3208       return error_mark_node;
3209     }
3210
3211   if (TREE_CODE (type) == FUNCTION_TYPE)
3212     {
3213       error ("cast specifies function type");
3214       return error_mark_node;
3215     }
3216
3217   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3218     {
3219       if (pedantic)
3220         {
3221           if (TREE_CODE (type) == RECORD_TYPE
3222               || TREE_CODE (type) == UNION_TYPE)
3223             pedwarn ("ISO C forbids casting nonscalar to the same type");
3224         }
3225     }
3226   else if (TREE_CODE (type) == UNION_TYPE)
3227     {
3228       tree field;
3229
3230       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3231         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3232                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3233           break;
3234
3235       if (field)
3236         {
3237           tree t;
3238
3239           if (pedantic)
3240             pedwarn ("ISO C forbids casts to union type");
3241           t = digest_init (type,
3242                            build_constructor_single (type, field, value),
3243                            true, 0);
3244           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3245           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3246           return t;
3247         }
3248       error ("cast to union type from type not present in union");
3249       return error_mark_node;
3250     }
3251   else
3252     {
3253       tree otype, ovalue;
3254
3255       if (type == void_type_node)
3256         return build1 (CONVERT_EXPR, type, value);
3257
3258       otype = TREE_TYPE (value);
3259
3260       /* Optionally warn about potentially worrisome casts.  */
3261
3262       if (warn_cast_qual
3263           && TREE_CODE (type) == POINTER_TYPE
3264           && TREE_CODE (otype) == POINTER_TYPE)
3265         {
3266           tree in_type = type;
3267           tree in_otype = otype;
3268           int added = 0;
3269           int discarded = 0;
3270
3271           /* Check that the qualifiers on IN_TYPE are a superset of
3272              the qualifiers of IN_OTYPE.  The outermost level of
3273              POINTER_TYPE nodes is uninteresting and we stop as soon
3274              as we hit a non-POINTER_TYPE node on either type.  */
3275           do
3276             {
3277               in_otype = TREE_TYPE (in_otype);
3278               in_type = TREE_TYPE (in_type);
3279
3280               /* GNU C allows cv-qualified function types.  'const'
3281                  means the function is very pure, 'volatile' means it
3282                  can't return.  We need to warn when such qualifiers
3283                  are added, not when they're taken away.  */
3284               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3285                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3286                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3287               else
3288                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3289             }
3290           while (TREE_CODE (in_type) == POINTER_TYPE
3291                  && TREE_CODE (in_otype) == POINTER_TYPE);
3292
3293           if (added)
3294             warning (0, "cast adds new qualifiers to function type");
3295
3296           if (discarded)
3297             /* There are qualifiers present in IN_OTYPE that are not
3298                present in IN_TYPE.  */
3299             warning (0, "cast discards qualifiers from pointer target type");
3300         }
3301
3302       /* Warn about possible alignment problems.  */
3303       if (STRICT_ALIGNMENT
3304           && TREE_CODE (type) == POINTER_TYPE
3305           && TREE_CODE (otype) == POINTER_TYPE
3306           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3307           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3308           /* Don't warn about opaque types, where the actual alignment
3309              restriction is unknown.  */
3310           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3311                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3312                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3313           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3314         warning (OPT_Wcast_align,
3315                  "cast increases required alignment of target type");
3316
3317       if (TREE_CODE (type) == INTEGER_TYPE
3318           && TREE_CODE (otype) == POINTER_TYPE
3319           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3320           && !TREE_CONSTANT (value))
3321         warning (OPT_Wpointer_to_int_cast,
3322                  "cast from pointer to integer of different size");
3323
3324       if (TREE_CODE (value) == CALL_EXPR
3325           && TREE_CODE (type) != TREE_CODE (otype))
3326         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3327                  "to non-matching type %qT", otype, type);
3328
3329       if (TREE_CODE (type) == POINTER_TYPE
3330           && TREE_CODE (otype) == INTEGER_TYPE
3331           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3332           /* Don't warn about converting any constant.  */
3333           && !TREE_CONSTANT (value))
3334         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3335                  "of different size");
3336
3337       if (flag_strict_aliasing && warn_strict_aliasing
3338           && TREE_CODE (type) == POINTER_TYPE
3339           && TREE_CODE (otype) == POINTER_TYPE
3340           && TREE_CODE (expr) == ADDR_EXPR
3341           && (DECL_P (TREE_OPERAND (expr, 0))
3342               || TREE_CODE (TREE_OPERAND (expr, 0)) == COMPONENT_REF)
3343           && !VOID_TYPE_P (TREE_TYPE (type)))
3344         {
3345           /* Casting the address of an object to non void pointer. Warn
3346              if the cast breaks type based aliasing.  */
3347           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3348             warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
3349                      "might break strict-aliasing rules");
3350           else
3351             {
3352               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3353               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3354
3355               if (!alias_sets_conflict_p (set1, set2))
3356                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3357                          "pointer will break strict-aliasing rules");
3358               else if (warn_strict_aliasing > 1
3359                        && !alias_sets_might_conflict_p (set1, set2))
3360                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3361                          "pointer might break strict-aliasing rules");
3362             }
3363         }
3364
3365       /* If pedantic, warn for conversions between function and object
3366          pointer types, except for converting a null pointer constant
3367          to function pointer type.  */
3368       if (pedantic
3369           && TREE_CODE (type) == POINTER_TYPE
3370           && TREE_CODE (otype) == POINTER_TYPE
3371           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3372           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3373         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3374
3375       if (pedantic
3376           && TREE_CODE (type) == POINTER_TYPE
3377           && TREE_CODE (otype) == POINTER_TYPE
3378           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3379           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3380           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3381                && TREE_CODE (expr) != NOP_EXPR))
3382         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3383
3384       ovalue = value;
3385       value = convert (type, value);
3386
3387       /* Ignore any integer overflow caused by the cast.  */
3388       if (TREE_CODE (value) == INTEGER_CST)
3389         {
3390           /* If OVALUE had overflow set, then so will VALUE, so it
3391              is safe to overwrite.  */
3392           if (CONSTANT_CLASS_P (ovalue))
3393             {
3394               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3395               /* Similarly, constant_overflow cannot have become cleared.  */
3396               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3397             }
3398           else
3399             TREE_OVERFLOW (value) = 0;
3400         }
3401     }
3402
3403   /* Don't let a cast be an lvalue.  */
3404   if (value == expr)
3405     value = non_lvalue (value);
3406
3407   return value;
3408 }
3409
3410 /* Interpret a cast of expression EXPR to type TYPE.  */
3411 tree
3412 c_cast_expr (struct c_type_name *type_name, tree expr)
3413 {
3414   tree type;
3415   int saved_wsp = warn_strict_prototypes;
3416
3417   /* This avoids warnings about unprototyped casts on
3418      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3419   if (TREE_CODE (expr) == INTEGER_CST)
3420     warn_strict_prototypes = 0;
3421   type = groktypename (type_name);
3422   warn_strict_prototypes = saved_wsp;
3423
3424   return build_c_cast (type, expr);
3425 }
3426
3427 \f
3428 /* Build an assignment expression of lvalue LHS from value RHS.
3429    MODIFYCODE is the code for a binary operator that we use
3430    to combine the old value of LHS with RHS to get the new value.
3431    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3432
3433 tree
3434 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3435 {
3436   tree result;
3437   tree newrhs;
3438   tree lhstype = TREE_TYPE (lhs);
3439   tree olhstype = lhstype;
3440
3441   /* Types that aren't fully specified cannot be used in assignments.  */
3442   lhs = require_complete_type (lhs);
3443
3444   /* Avoid duplicate error messages from operands that had errors.  */
3445   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3446     return error_mark_node;
3447
3448   STRIP_TYPE_NOPS (rhs);
3449
3450   newrhs = rhs;
3451
3452   /* If a binary op has been requested, combine the old LHS value with the RHS
3453      producing the value we should actually store into the LHS.  */
3454
3455   if (modifycode != NOP_EXPR)
3456     {
3457       lhs = stabilize_reference (lhs);
3458       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3459     }
3460
3461   if (!lvalue_or_else (lhs, lv_assign))
3462     return error_mark_node;
3463
3464   /* Give an error for storing in something that is 'const'.  */
3465
3466   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3467       || ((TREE_CODE (lhstype) == RECORD_TYPE
3468            || TREE_CODE (lhstype) == UNION_TYPE)
3469           && C_TYPE_FIELDS_READONLY (lhstype)))
3470     readonly_error (lhs, lv_assign);
3471
3472   /* If storing into a structure or union member,
3473      it has probably been given type `int'.
3474      Compute the type that would go with
3475      the actual amount of storage the member occupies.  */
3476
3477   if (TREE_CODE (lhs) == COMPONENT_REF
3478       && (TREE_CODE (lhstype) == INTEGER_TYPE
3479           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3480           || TREE_CODE (lhstype) == REAL_TYPE
3481           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3482     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3483
3484   /* If storing in a field that is in actuality a short or narrower than one,
3485      we must store in the field in its actual type.  */
3486
3487   if (lhstype != TREE_TYPE (lhs))
3488     {
3489       lhs = copy_node (lhs);
3490       TREE_TYPE (lhs) = lhstype;
3491     }
3492
3493   /* Convert new value to destination type.  */
3494
3495   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3496                                    NULL_TREE, NULL_TREE, 0);
3497   if (TREE_CODE (newrhs) == ERROR_MARK)
3498     return error_mark_node;
3499
3500   /* Emit ObjC write barrier, if necessary.  */
3501   if (c_dialect_objc () && flag_objc_gc)
3502     {
3503       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3504       if (result)
3505         return result;
3506     }
3507
3508   /* Scan operands.  */
3509
3510   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3511   TREE_SIDE_EFFECTS (result) = 1;
3512
3513   /* If we got the LHS in a different type for storing in,
3514      convert the result back to the nominal type of LHS
3515      so that the value we return always has the same type
3516      as the LHS argument.  */
3517
3518   if (olhstype == TREE_TYPE (result))
3519     return result;
3520   return convert_for_assignment (olhstype, result, ic_assign,
3521                                  NULL_TREE, NULL_TREE, 0);
3522 }
3523 \f
3524 /* Convert value RHS to type TYPE as preparation for an assignment
3525    to an lvalue of type TYPE.
3526    The real work of conversion is done by `convert'.
3527    The purpose of this function is to generate error messages
3528    for assignments that are not allowed in C.
3529    ERRTYPE says whether it is argument passing, assignment,
3530    initialization or return.
3531
3532    FUNCTION is a tree for the function being called.
3533    PARMNUM is the number of the argument, for printing in error messages.  */
3534
3535 static tree
3536 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3537                         tree fundecl, tree function, int parmnum)
3538 {
3539   enum tree_code codel = TREE_CODE (type);
3540   tree rhstype;
3541   enum tree_code coder;
3542   tree rname = NULL_TREE;
3543   bool objc_ok = false;
3544
3545   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3546     {
3547       tree selector;
3548       /* Change pointer to function to the function itself for
3549          diagnostics.  */
3550       if (TREE_CODE (function) == ADDR_EXPR
3551           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3552         function = TREE_OPERAND (function, 0);
3553
3554       /* Handle an ObjC selector specially for diagnostics.  */
3555       selector = objc_message_selector ();
3556       rname = function;
3557       if (selector && parmnum > 2)
3558         {
3559           rname = selector;
3560           parmnum -= 2;
3561         }
3562     }
3563
3564   /* This macro is used to emit diagnostics to ensure that all format
3565      strings are complete sentences, visible to gettext and checked at
3566      compile time.  */
3567 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3568   do {                                          \
3569     switch (errtype)                            \
3570       {                                         \
3571       case ic_argpass:                          \
3572         pedwarn (AR, parmnum, rname);           \
3573         break;                                  \
3574       case ic_argpass_nonproto:                 \
3575         warning (0, AR, parmnum, rname);                \
3576         break;                                  \
3577       case ic_assign:                           \
3578         pedwarn (AS);                           \
3579         break;                                  \
3580       case ic_init:                             \
3581         pedwarn (IN);                           \
3582         break;                                  \
3583       case ic_return:                           \
3584         pedwarn (RE);                           \
3585         break;                                  \
3586       default:                                  \
3587         gcc_unreachable ();                     \
3588       }                                         \
3589   } while (0)
3590
3591   STRIP_TYPE_NOPS (rhs);
3592
3593   if (optimize && TREE_CODE (rhs) == VAR_DECL
3594            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3595     rhs = decl_constant_value_for_broken_optimization (rhs);
3596
3597   rhstype = TREE_TYPE (rhs);
3598   coder = TREE_CODE (rhstype);
3599
3600   if (coder == ERROR_MARK)
3601     return error_mark_node;
3602
3603   if (c_dialect_objc ())
3604     {
3605       int parmno;
3606
3607       switch (errtype)
3608         {
3609         case ic_return:
3610           parmno = 0;
3611           break;
3612
3613         case ic_assign:
3614           parmno = -1;
3615           break;
3616
3617         case ic_init:
3618           parmno = -2;
3619           break;
3620
3621         default:
3622           parmno = parmnum;
3623           break;
3624         }
3625
3626       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3627     }
3628
3629   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3630     {
3631       overflow_warning (rhs);
3632       return rhs;
3633     }
3634
3635   if (coder == VOID_TYPE)
3636     {
3637       /* Except for passing an argument to an unprototyped function,
3638          this is a constraint violation.  When passing an argument to
3639          an unprototyped function, it is compile-time undefined;
3640          making it a constraint in that case was rejected in
3641          DR#252.  */
3642       error ("void value not ignored as it ought to be");
3643       return error_mark_node;
3644     }
3645   /* A type converts to a reference to it.
3646      This code doesn't fully support references, it's just for the
3647      special case of va_start and va_copy.  */
3648   if (codel == REFERENCE_TYPE
3649       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3650     {
3651       if (!lvalue_p (rhs))
3652         {
3653           error ("cannot pass rvalue to reference parameter");
3654           return error_mark_node;
3655         }
3656       if (!c_mark_addressable (rhs))
3657         return error_mark_node;
3658       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3659
3660       /* We already know that these two types are compatible, but they
3661          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3662          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3663          likely to be va_list, a typedef to __builtin_va_list, which
3664          is different enough that it will cause problems later.  */
3665       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3666         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3667
3668       rhs = build1 (NOP_EXPR, type, rhs);
3669       return rhs;
3670     }
3671   /* Some types can interconvert without explicit casts.  */
3672   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3673            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3674     return convert (type, rhs);
3675   /* Arithmetic types all interconvert, and enum is treated like int.  */
3676   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3677             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3678             || codel == BOOLEAN_TYPE)
3679            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3680                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3681                || coder == BOOLEAN_TYPE))
3682     return convert_and_check (type, rhs);
3683
3684   /* Conversion to a transparent union from its member types.
3685      This applies only to function arguments.  */
3686   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3687            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3688     {
3689       tree memb_types;
3690       tree marginal_memb_type = 0;
3691
3692       for (memb_types = TYPE_FIELDS (type); memb_types;
3693            memb_types = TREE_CHAIN (memb_types))
3694         {
3695           tree memb_type = TREE_TYPE (memb_types);
3696
3697           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3698                          TYPE_MAIN_VARIANT (rhstype)))
3699             break;
3700
3701           if (TREE_CODE (memb_type) != POINTER_TYPE)
3702             continue;
3703
3704           if (coder == POINTER_TYPE)
3705             {
3706               tree ttl = TREE_TYPE (memb_type);
3707               tree ttr = TREE_TYPE (rhstype);
3708
3709               /* Any non-function converts to a [const][volatile] void *
3710                  and vice versa; otherwise, targets must be the same.
3711                  Meanwhile, the lhs target must have all the qualifiers of
3712                  the rhs.  */
3713               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3714                   || comp_target_types (memb_type, rhstype))
3715                 {
3716                   /* If this type won't generate any warnings, use it.  */
3717                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3718                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3719                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3720                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3721                              == TYPE_QUALS (ttr))
3722                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3723                              == TYPE_QUALS (ttl))))
3724                     break;
3725
3726                   /* Keep looking for a better type, but remember this one.  */
3727                   if (!marginal_memb_type)
3728                     marginal_memb_type = memb_type;
3729                 }
3730             }
3731
3732           /* Can convert integer zero to any pointer type.  */
3733           if (integer_zerop (rhs)
3734               || (TREE_CODE (rhs) == NOP_EXPR
3735                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3736             {
3737               rhs = null_pointer_node;
3738               break;
3739             }
3740         }
3741
3742       if (memb_types || marginal_memb_type)
3743         {
3744           if (!memb_types)
3745             {
3746               /* We have only a marginally acceptable member type;
3747                  it needs a warning.  */
3748               tree ttl = TREE_TYPE (marginal_memb_type);
3749               tree ttr = TREE_TYPE (rhstype);
3750
3751               /* Const and volatile mean something different for function
3752                  types, so the usual warnings are not appropriate.  */
3753               if (TREE_CODE (ttr) == FUNCTION_TYPE
3754                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3755                 {
3756                   /* Because const and volatile on functions are
3757                      restrictions that say the function will not do
3758                      certain things, it is okay to use a const or volatile
3759                      function where an ordinary one is wanted, but not
3760                      vice-versa.  */
3761                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3762                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3763                                             "makes qualified function "
3764                                             "pointer from unqualified"),
3765                                          G_("assignment makes qualified "
3766                                             "function pointer from "
3767                                             "unqualified"),
3768                                          G_("initialization makes qualified "
3769                                             "function pointer from "
3770                                             "unqualified"),
3771                                          G_("return makes qualified function "
3772                                             "pointer from unqualified"));
3773                 }
3774               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3775                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3776                                         "qualifiers from pointer target type"),
3777                                      G_("assignment discards qualifiers "
3778                                         "from pointer target type"),
3779                                      G_("initialization discards qualifiers "
3780                                         "from pointer target type"),
3781                                      G_("return discards qualifiers from "
3782                                         "pointer target type"));
3783             }
3784
3785           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3786             pedwarn ("ISO C prohibits argument conversion to union type");
3787
3788           return build1 (NOP_EXPR, type, rhs);
3789         }
3790     }
3791
3792   /* Conversions among pointers */
3793   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3794            && (coder == codel))
3795     {
3796       tree ttl = TREE_TYPE (type);
3797       tree ttr = TREE_TYPE (rhstype);
3798       tree mvl = ttl;
3799       tree mvr = ttr;
3800       bool is_opaque_pointer;
3801       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3802
3803       if (TREE_CODE (mvl) != ARRAY_TYPE)
3804         mvl = TYPE_MAIN_VARIANT (mvl);
3805       if (TREE_CODE (mvr) != ARRAY_TYPE)
3806         mvr = TYPE_MAIN_VARIANT (mvr);
3807       /* Opaque pointers are treated like void pointers.  */
3808       is_opaque_pointer = (targetm.vector_opaque_p (type)
3809                            || targetm.vector_opaque_p (rhstype))
3810         && TREE_CODE (ttl) == VECTOR_TYPE
3811         && TREE_CODE (ttr) == VECTOR_TYPE;
3812
3813       /* C++ does not allow the implicit conversion void* -> T*.  However,
3814          for the purpose of reducing the number of false positives, we
3815          tolerate the special case of
3816
3817                 int *p = NULL;
3818
3819          where NULL is typically defined in C to be '(void *) 0'.  */
3820       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3821         warning (OPT_Wc___compat, "request for implicit conversion from "
3822                  "%qT to %qT not permitted in C++", rhstype, type);
3823
3824       /* Check if the right-hand side has a format attribute but the
3825          left-hand side doesn't.  */
3826       if (warn_missing_format_attribute
3827           && check_missing_format_attribute (type, rhstype))
3828         {
3829           switch (errtype)
3830           {
3831           case ic_argpass:
3832           case ic_argpass_nonproto:
3833             warning (OPT_Wmissing_format_attribute,
3834                      "argument %d of %qE might be "
3835                      "a candidate for a format attribute",
3836                      parmnum, rname);
3837             break;
3838           case ic_assign:
3839             warning (OPT_Wmissing_format_attribute,
3840                      "assignment left-hand side might be "
3841                      "a candidate for a format attribute");
3842             break;
3843           case ic_init:
3844             warning (OPT_Wmissing_format_attribute,
3845                      "initialization left-hand side might be "
3846                      "a candidate for a format attribute");
3847             break;
3848           case ic_return:
3849             warning (OPT_Wmissing_format_attribute,
3850                      "return type might be "
3851                      "a candidate for a format attribute");
3852             break;
3853           default:
3854             gcc_unreachable ();
3855           }
3856         }
3857
3858       /* Any non-function converts to a [const][volatile] void *
3859          and vice versa; otherwise, targets must be the same.
3860          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3861       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3862           || (target_cmp = comp_target_types (type, rhstype))
3863           || is_opaque_pointer
3864           || (c_common_unsigned_type (mvl)
3865               == c_common_unsigned_type (mvr)))
3866         {
3867           if (pedantic
3868               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3869                   ||
3870                   (VOID_TYPE_P (ttr)
3871                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3872                       which are not ANSI null ptr constants.  */
3873                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3874                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3875             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3876                                     "%qE between function pointer "
3877                                     "and %<void *%>"),
3878                                  G_("ISO C forbids assignment between "
3879                                     "function pointer and %<void *%>"),
3880                                  G_("ISO C forbids initialization between "
3881                                     "function pointer and %<void *%>"),
3882                                  G_("ISO C forbids return between function "
3883                                     "pointer and %<void *%>"));
3884           /* Const and volatile mean something different for function types,
3885              so the usual warnings are not appropriate.  */
3886           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3887                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3888             {
3889               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3890                 {
3891                   /* Types differing only by the presence of the 'volatile'
3892                      qualifier are acceptable if the 'volatile' has been added
3893                      in by the Objective-C EH machinery.  */
3894                   if (!objc_type_quals_match (ttl, ttr))
3895                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3896                                             "qualifiers from pointer target type"),
3897                                          G_("assignment discards qualifiers "
3898                                             "from pointer target type"),
3899                                          G_("initialization discards qualifiers "
3900                                             "from pointer target type"),
3901                                          G_("return discards qualifiers from "
3902                                             "pointer target type"));
3903                 }
3904               /* If this is not a case of ignoring a mismatch in signedness,
3905                  no warning.  */
3906               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3907                        || target_cmp)
3908                 ;
3909               /* If there is a mismatch, do warn.  */
3910               else if (warn_pointer_sign)
3911                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
3912                                         "%d of %qE differ in signedness"),
3913                                      G_("pointer targets in assignment "
3914                                         "differ in signedness"),
3915                                      G_("pointer targets in initialization "
3916                                         "differ in signedness"),
3917                                      G_("pointer targets in return differ "
3918                                         "in signedness"));
3919             }
3920           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3921                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3922             {
3923               /* Because const and volatile on functions are restrictions
3924                  that say the function will not do certain things,
3925                  it is okay to use a const or volatile function
3926                  where an ordinary one is wanted, but not vice-versa.  */
3927               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3928                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3929                                         "qualified function pointer "
3930                                         "from unqualified"),
3931                                      G_("assignment makes qualified function "
3932                                         "pointer from unqualified"),
3933                                      G_("initialization makes qualified "
3934                                         "function pointer from unqualified"),
3935                                      G_("return makes qualified function "
3936                                         "pointer from unqualified"));
3937             }
3938         }
3939       else
3940         /* Avoid warning about the volatile ObjC EH puts on decls.  */
3941         if (!objc_ok)
3942           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
3943                                   "incompatible pointer type"),
3944                                G_("assignment from incompatible pointer type"),
3945                                G_("initialization from incompatible "
3946                                   "pointer type"),
3947                                G_("return from incompatible pointer type"));
3948
3949       return convert (type, rhs);
3950     }
3951   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3952     {
3953       /* ??? This should not be an error when inlining calls to
3954          unprototyped functions.  */
3955       error ("invalid use of non-lvalue array");
3956       return error_mark_node;
3957     }
3958   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3959     {
3960       /* An explicit constant 0 can convert to a pointer,
3961          or one that results from arithmetic, even including
3962          a cast to integer type.  */
3963       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3964           &&
3965           !(TREE_CODE (rhs) == NOP_EXPR
3966             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3967             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3968             && integer_zerop (TREE_OPERAND (rhs, 0))))
3969         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
3970                                 "pointer from integer without a cast"),
3971                              G_("assignment makes pointer from integer "
3972                                 "without a cast"),
3973                              G_("initialization makes pointer from "
3974                                 "integer without a cast"),
3975                              G_("return makes pointer from integer "
3976                                 "without a cast"));
3977
3978       return convert (type, rhs);
3979     }
3980   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3981     {
3982       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
3983                               "from pointer without a cast"),
3984                            G_("assignment makes integer from pointer "
3985                               "without a cast"),
3986                            G_("initialization makes integer from pointer "
3987                               "without a cast"),
3988                            G_("return makes integer from pointer "
3989                               "without a cast"));
3990       return convert (type, rhs);
3991     }
3992   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3993     return convert (type, rhs);
3994
3995   switch (errtype)
3996     {
3997     case ic_argpass:
3998     case ic_argpass_nonproto:
3999       /* ??? This should not be an error when inlining calls to
4000          unprototyped functions.  */
4001       error ("incompatible type for argument %d of %qE", parmnum, rname);
4002       break;
4003     case ic_assign:
4004       error ("incompatible types in assignment");
4005       break;
4006     case ic_init:
4007       error ("incompatible types in initialization");
4008       break;
4009     case ic_return:
4010       error ("incompatible types in return");
4011       break;
4012     default:
4013       gcc_unreachable ();
4014     }
4015
4016   return error_mark_node;
4017 }
4018
4019 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4020    is used for error and waring reporting and indicates which argument
4021    is being processed.  */
4022
4023 tree
4024 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4025 {
4026   tree ret, type;
4027
4028   /* If FN was prototyped, the value has been converted already
4029      in convert_arguments.  */
4030   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4031     return value;
4032
4033   type = TREE_TYPE (parm);
4034   ret = convert_for_assignment (type, value,
4035                                 ic_argpass_nonproto, fn,
4036                                 fn, argnum);
4037   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4038       && INTEGRAL_TYPE_P (type)
4039       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4040     ret = default_conversion (ret);
4041   return ret;
4042 }
4043 \f
4044 /* If VALUE is a compound expr all of whose expressions are constant, then
4045    return its value.  Otherwise, return error_mark_node.
4046
4047    This is for handling COMPOUND_EXPRs as initializer elements
4048    which is allowed with a warning when -pedantic is specified.  */
4049
4050 static tree
4051 valid_compound_expr_initializer (tree value, tree endtype)
4052 {
4053   if (TREE_CODE (value) == COMPOUND_EXPR)
4054     {
4055       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4056           == error_mark_node)
4057         return error_mark_node;
4058       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4059                                               endtype);
4060     }
4061   else if (!initializer_constant_valid_p (value, endtype))
4062     return error_mark_node;
4063   else
4064     return value;
4065 }
4066 \f
4067 /* Perform appropriate conversions on the initial value of a variable,
4068    store it in the declaration DECL,
4069    and print any error messages that are appropriate.
4070    If the init is invalid, store an ERROR_MARK.  */
4071
4072 void
4073 store_init_value (tree decl, tree init)
4074 {
4075   tree value, type;
4076
4077   /* If variable's type was invalidly declared, just ignore it.  */
4078
4079   type = TREE_TYPE (decl);
4080   if (TREE_CODE (type) == ERROR_MARK)
4081     return;
4082
4083   /* Digest the specified initializer into an expression.  */
4084
4085   value = digest_init (type, init, true, TREE_STATIC (decl));
4086
4087   /* Store the expression if valid; else report error.  */
4088
4089   if (!in_system_header
4090       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4091     warning (OPT_Wtraditional, "traditional C rejects automatic "
4092              "aggregate initialization");
4093
4094   DECL_INITIAL (decl) = value;
4095
4096   /* ANSI wants warnings about out-of-range constant initializers.  */
4097   STRIP_TYPE_NOPS (value);
4098   constant_expression_warning (value);
4099
4100   /* Check if we need to set array size from compound literal size.  */
4101   if (TREE_CODE (type) == ARRAY_TYPE
4102       && TYPE_DOMAIN (type) == 0
4103       && value != error_mark_node)
4104     {
4105       tree inside_init = init;
4106
4107       STRIP_TYPE_NOPS (inside_init);
4108       inside_init = fold (inside_init);
4109
4110       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4111         {
4112           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4113
4114           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4115             {
4116               /* For int foo[] = (int [3]){1}; we need to set array size
4117                  now since later on array initializer will be just the
4118                  brace enclosed list of the compound literal.  */
4119               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4120               layout_type (type);
4121               layout_decl (decl, 0);
4122             }
4123         }
4124     }
4125 }
4126 \f
4127 /* Methods for storing and printing names for error messages.  */
4128
4129 /* Implement a spelling stack that allows components of a name to be pushed
4130    and popped.  Each element on the stack is this structure.  */
4131
4132 struct spelling
4133 {
4134   int kind;
4135   union
4136     {
4137       int i;
4138       const char *s;
4139     } u;
4140 };
4141
4142 #define SPELLING_STRING 1
4143 #define SPELLING_MEMBER 2
4144 #define SPELLING_BOUNDS 3
4145
4146 static struct spelling *spelling;       /* Next stack element (unused).  */
4147 static struct spelling *spelling_base;  /* Spelling stack base.  */
4148 static int spelling_size;               /* Size of the spelling stack.  */
4149
4150 /* Macros to save and restore the spelling stack around push_... functions.
4151    Alternative to SAVE_SPELLING_STACK.  */
4152
4153 #define SPELLING_DEPTH() (spelling - spelling_base)
4154 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4155
4156 /* Push an element on the spelling stack with type KIND and assign VALUE
4157    to MEMBER.  */
4158
4159 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4160 {                                                                       \
4161   int depth = SPELLING_DEPTH ();                                        \
4162                                                                         \
4163   if (depth >= spelling_size)                                           \
4164     {                                                                   \
4165       spelling_size += 10;                                              \
4166       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4167                                   spelling_size);                       \
4168       RESTORE_SPELLING_DEPTH (depth);                                   \
4169     }                                                                   \
4170                                                                         \
4171   spelling->kind = (KIND);                                              \
4172   spelling->MEMBER = (VALUE);                                           \
4173   spelling++;                                                           \
4174 }
4175
4176 /* Push STRING on the stack.  Printed literally.  */
4177
4178 static void
4179 push_string (const char *string)
4180 {
4181   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4182 }
4183
4184 /* Push a member name on the stack.  Printed as '.' STRING.  */
4185
4186 static void
4187 push_member_name (tree decl)
4188 {
4189   const char *const string
4190     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4191   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4192 }
4193
4194 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4195
4196 static void
4197 push_array_bounds (int bounds)
4198 {
4199   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4200 }
4201
4202 /* Compute the maximum size in bytes of the printed spelling.  */
4203
4204 static int
4205 spelling_length (void)
4206 {
4207   int size = 0;
4208   struct spelling *p;
4209
4210   for (p = spelling_base; p < spelling; p++)
4211     {
4212       if (p->kind == SPELLING_BOUNDS)
4213         size += 25;
4214       else
4215         size += strlen (p->u.s) + 1;
4216     }
4217
4218   return size;
4219 }
4220
4221 /* Print the spelling to BUFFER and return it.  */
4222
4223 static char *
4224 print_spelling (char *buffer)
4225 {
4226   char *d = buffer;
4227   struct spelling *p;
4228
4229   for (p = spelling_base; p < spelling; p++)
4230     if (p->kind == SPELLING_BOUNDS)
4231       {
4232         sprintf (d, "[%d]", p->u.i);
4233         d += strlen (d);
4234       }
4235     else
4236       {
4237         const char *s;
4238         if (p->kind == SPELLING_MEMBER)
4239           *d++ = '.';
4240         for (s = p->u.s; (*d = *s++); d++)
4241           ;
4242       }
4243   *d++ = '\0';
4244   return buffer;
4245 }
4246
4247 /* Issue an error message for a bad initializer component.
4248    MSGID identifies the message.
4249    The component name is taken from the spelling stack.  */
4250
4251 void
4252 error_init (const char *msgid)
4253 {
4254   char *ofwhat;
4255
4256   error ("%s", _(msgid));
4257   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4258   if (*ofwhat)
4259     error ("(near initialization for %qs)", ofwhat);
4260 }
4261
4262 /* Issue a pedantic warning for a bad initializer component.
4263    MSGID identifies the message.
4264    The component name is taken from the spelling stack.  */
4265
4266 void
4267 pedwarn_init (const char *msgid)
4268 {
4269   char *ofwhat;
4270
4271   pedwarn ("%s", _(msgid));
4272   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4273   if (*ofwhat)
4274     pedwarn ("(near initialization for %qs)", ofwhat);
4275 }
4276
4277 /* Issue a warning for a bad initializer component.
4278    MSGID identifies the message.
4279    The component name is taken from the spelling stack.  */
4280
4281 static void
4282 warning_init (const char *msgid)
4283 {
4284   char *ofwhat;
4285
4286   warning (0, "%s", _(msgid));
4287   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4288   if (*ofwhat)
4289     warning (0, "(near initialization for %qs)", ofwhat);
4290 }
4291 \f
4292 /* If TYPE is an array type and EXPR is a parenthesized string
4293    constant, warn if pedantic that EXPR is being used to initialize an
4294    object of type TYPE.  */
4295
4296 void
4297 maybe_warn_string_init (tree type, struct c_expr expr)
4298 {
4299   if (pedantic
4300       && TREE_CODE (type) == ARRAY_TYPE
4301       && TREE_CODE (expr.value) == STRING_CST
4302       && expr.original_code != STRING_CST)
4303     pedwarn_init ("array initialized from parenthesized string constant");
4304 }
4305
4306 /* Digest the parser output INIT as an initializer for type TYPE.
4307    Return a C expression of type TYPE to represent the initial value.
4308
4309    If INIT is a string constant, STRICT_STRING is true if it is
4310    unparenthesized or we should not warn here for it being parenthesized.
4311    For other types of INIT, STRICT_STRING is not used.
4312
4313    REQUIRE_CONSTANT requests an error if non-constant initializers or
4314    elements are seen.  */
4315
4316 static tree
4317 digest_init (tree type, tree init, bool strict_string, int require_constant)
4318 {
4319   enum tree_code code = TREE_CODE (type);
4320   tree inside_init = init;
4321
4322   if (type == error_mark_node
4323       || init == error_mark_node
4324       || TREE_TYPE (init) == error_mark_node)
4325     return error_mark_node;
4326
4327   STRIP_TYPE_NOPS (inside_init);
4328
4329   inside_init = fold (inside_init);
4330
4331   /* Initialization of an array of chars from a string constant
4332      optionally enclosed in braces.  */
4333
4334   if (code == ARRAY_TYPE && inside_init
4335       && TREE_CODE (inside_init) == STRING_CST)
4336     {
4337       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4338       /* Note that an array could be both an array of character type
4339          and an array of wchar_t if wchar_t is signed char or unsigned
4340          char.  */
4341       bool char_array = (typ1 == char_type_node
4342                          || typ1 == signed_char_type_node
4343                          || typ1 == unsigned_char_type_node);
4344       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4345       if (char_array || wchar_array)
4346         {
4347           struct c_expr expr;
4348           bool char_string;
4349           expr.value = inside_init;
4350           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4351           maybe_warn_string_init (type, expr);
4352
4353           char_string
4354             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4355                == char_type_node);
4356
4357           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4358                          TYPE_MAIN_VARIANT (type)))
4359             return inside_init;
4360
4361           if (!wchar_array && !char_string)
4362             {
4363               error_init ("char-array initialized from wide string");
4364               return error_mark_node;
4365             }
4366           if (char_string && !char_array)
4367             {
4368               error_init ("wchar_t-array initialized from non-wide string");
4369               return error_mark_node;
4370             }
4371
4372           TREE_TYPE (inside_init) = type;
4373           if (TYPE_DOMAIN (type) != 0
4374               && TYPE_SIZE (type) != 0
4375               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4376               /* Subtract 1 (or sizeof (wchar_t))
4377                  because it's ok to ignore the terminating null char
4378                  that is counted in the length of the constant.  */
4379               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4380                                        TREE_STRING_LENGTH (inside_init)
4381                                        - ((TYPE_PRECISION (typ1)
4382                                            != TYPE_PRECISION (char_type_node))
4383                                           ? (TYPE_PRECISION (wchar_type_node)
4384                                              / BITS_PER_UNIT)
4385                                           : 1)))
4386             pedwarn_init ("initializer-string for array of chars is too long");
4387
4388           return inside_init;
4389         }
4390       else if (INTEGRAL_TYPE_P (typ1))
4391         {
4392           error_init ("array of inappropriate type initialized "
4393                       "from string constant");
4394           return error_mark_node;
4395         }
4396     }
4397
4398   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4399      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4400      below and handle as a constructor.  */
4401   if (code == VECTOR_TYPE
4402       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4403       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4404       && TREE_CONSTANT (inside_init))
4405     {
4406       if (TREE_CODE (inside_init) == VECTOR_CST
4407           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4408                         TYPE_MAIN_VARIANT (type)))
4409         return inside_init;
4410
4411       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4412         {
4413           unsigned HOST_WIDE_INT ix;
4414           tree value;
4415           bool constant_p = true;
4416
4417           /* Iterate through elements and check if all constructor
4418              elements are *_CSTs.  */
4419           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4420             if (!CONSTANT_CLASS_P (value))
4421               {
4422                 constant_p = false;
4423                 break;
4424               }
4425
4426           if (constant_p)
4427             return build_vector_from_ctor (type,
4428                                            CONSTRUCTOR_ELTS (inside_init));
4429         }
4430     }
4431
4432   /* Any type can be initialized
4433      from an expression of the same type, optionally with braces.  */
4434
4435   if (inside_init && TREE_TYPE (inside_init) != 0
4436       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4437                      TYPE_MAIN_VARIANT (type))
4438           || (code == ARRAY_TYPE
4439               && comptypes (TREE_TYPE (inside_init), type))
4440           || (code == VECTOR_TYPE
4441               && comptypes (TREE_TYPE (inside_init), type))
4442           || (code == POINTER_TYPE
4443               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4444               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4445                             TREE_TYPE (type)))))
4446     {
4447       if (code == POINTER_TYPE)
4448         {
4449           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4450             {
4451               if (TREE_CODE (inside_init) == STRING_CST
4452                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4453                 inside_init = array_to_pointer_conversion (inside_init);
4454               else
4455                 {
4456                   error_init ("invalid use of non-lvalue array");
4457                   return error_mark_node;
4458                 }
4459             }
4460         }
4461
4462       if (code == VECTOR_TYPE)
4463         /* Although the types are compatible, we may require a
4464            conversion.  */
4465         inside_init = convert (type, inside_init);
4466
4467       if (require_constant && !flag_isoc99
4468           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4469         {
4470           /* As an extension, allow initializing objects with static storage
4471              duration with compound literals (which are then treated just as
4472              the brace enclosed list they contain).  */
4473           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4474           inside_init = DECL_INITIAL (decl);
4475         }
4476
4477       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4478           && TREE_CODE (inside_init) != CONSTRUCTOR)
4479         {
4480           error_init ("array initialized from non-constant array expression");
4481           return error_mark_node;
4482         }
4483
4484       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4485         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4486
4487       /* Compound expressions can only occur here if -pedantic or
4488          -pedantic-errors is specified.  In the later case, we always want
4489          an error.  In the former case, we simply want a warning.  */
4490       if (require_constant && pedantic
4491           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4492         {
4493           inside_init
4494             = valid_compound_expr_initializer (inside_init,
4495                                                TREE_TYPE (inside_init));
4496           if (inside_init == error_mark_node)
4497             error_init ("initializer element is not constant");
4498           else
4499             pedwarn_init ("initializer element is not constant");
4500           if (flag_pedantic_errors)
4501             inside_init = error_mark_node;
4502         }
4503       else if (require_constant
4504                && !initializer_constant_valid_p (inside_init,
4505                                                  TREE_TYPE (inside_init)))
4506         {
4507           error_init ("initializer element is not constant");
4508           inside_init = error_mark_node;
4509         }
4510
4511       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4512       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4513         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4514                                               NULL_TREE, 0);
4515       return inside_init;
4516     }
4517
4518   /* Handle scalar types, including conversions.  */
4519
4520   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4521       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4522       || code == VECTOR_TYPE)
4523     {
4524       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4525           && (TREE_CODE (init) == STRING_CST
4526               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4527         init = array_to_pointer_conversion (init);
4528       inside_init
4529         = convert_for_assignment (type, init, ic_init,
4530                                   NULL_TREE, NULL_TREE, 0);
4531
4532       /* Check to see if we have already given an error message.  */
4533       if (inside_init == error_mark_node)
4534         ;
4535       else if (require_constant && !TREE_CONSTANT (inside_init))
4536         {
4537           error_init ("initializer element is not constant");
4538           inside_init = error_mark_node;
4539         }
4540       else if (require_constant
4541                && !initializer_constant_valid_p (inside_init,
4542                                                  TREE_TYPE (inside_init)))
4543         {
4544           error_init ("initializer element is not computable at load time");
4545           inside_init = error_mark_node;
4546         }
4547
4548       return inside_init;
4549     }
4550
4551   /* Come here only for records and arrays.  */
4552
4553   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4554     {
4555       error_init ("variable-sized object may not be initialized");
4556       return error_mark_node;
4557     }
4558
4559   error_init ("invalid initializer");
4560   return error_mark_node;
4561 }
4562 \f
4563 /* Handle initializers that use braces.  */
4564
4565 /* Type of object we are accumulating a constructor for.
4566    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4567 static tree constructor_type;
4568
4569 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4570    left to fill.  */
4571 static tree constructor_fields;
4572
4573 /* For an ARRAY_TYPE, this is the specified index
4574    at which to store the next element we get.  */
4575 static tree constructor_index;
4576
4577 /* For an ARRAY_TYPE, this is the maximum index.  */
4578 static tree constructor_max_index;
4579
4580 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4581 static tree constructor_unfilled_fields;
4582
4583 /* For an ARRAY_TYPE, this is the index of the first element
4584    not yet written out.  */
4585 static tree constructor_unfilled_index;
4586
4587 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4588    This is so we can generate gaps between fields, when appropriate.  */
4589 static tree constructor_bit_index;
4590
4591 /* If we are saving up the elements rather than allocating them,
4592    this is the list of elements so far (in reverse order,
4593    most recent first).  */
4594 static VEC(constructor_elt,gc) *constructor_elements;
4595
4596 /* 1 if constructor should be incrementally stored into a constructor chain,
4597    0 if all the elements should be kept in AVL tree.  */
4598 static int constructor_incremental;
4599
4600 /* 1 if so far this constructor's elements are all compile-time constants.  */
4601 static int constructor_constant;
4602
4603 /* 1 if so far this constructor's elements are all valid address constants.  */
4604 static int constructor_simple;
4605
4606 /* 1 if this constructor is erroneous so far.  */
4607 static int constructor_erroneous;
4608
4609 /* Structure for managing pending initializer elements, organized as an
4610    AVL tree.  */
4611
4612 struct init_node
4613 {
4614   struct init_node *left, *right;
4615   struct init_node *parent;
4616   int balance;
4617   tree purpose;
4618   tree value;
4619 };
4620
4621 /* Tree of pending elements at this constructor level.
4622    These are elements encountered out of order
4623    which belong at places we haven't reached yet in actually
4624    writing the output.
4625    Will never hold tree nodes across GC runs.  */
4626 static struct init_node *constructor_pending_elts;
4627
4628 /* The SPELLING_DEPTH of this constructor.  */
4629 static int constructor_depth;
4630
4631 /* DECL node for which an initializer is being read.
4632    0 means we are reading a constructor expression
4633    such as (struct foo) {...}.  */
4634 static tree constructor_decl;
4635
4636 /* Nonzero if this is an initializer for a top-level decl.  */
4637 static int constructor_top_level;
4638
4639 /* Nonzero if there were any member designators in this initializer.  */
4640 static int constructor_designated;
4641
4642 /* Nesting depth of designator list.  */
4643 static int designator_depth;
4644
4645 /* Nonzero if there were diagnosed errors in this designator list.  */
4646 static int designator_errorneous;
4647
4648 \f
4649 /* This stack has a level for each implicit or explicit level of
4650    structuring in the initializer, including the outermost one.  It
4651    saves the values of most of the variables above.  */
4652
4653 struct constructor_range_stack;
4654
4655 struct constructor_stack
4656 {
4657   struct constructor_stack *next;
4658   tree type;
4659   tree fields;
4660   tree index;
4661   tree max_index;
4662   tree unfilled_index;
4663   tree unfilled_fields;
4664   tree bit_index;
4665   VEC(constructor_elt,gc) *elements;
4666   struct init_node *pending_elts;
4667   int offset;
4668   int depth;
4669   /* If value nonzero, this value should replace the entire
4670      constructor at this level.  */
4671   struct c_expr replacement_value;
4672   struct constructor_range_stack *range_stack;
4673   char constant;
4674   char simple;
4675   char implicit;
4676   char erroneous;
4677   char outer;
4678   char incremental;
4679   char designated;
4680 };
4681
4682 static struct constructor_stack *constructor_stack;
4683
4684 /* This stack represents designators from some range designator up to
4685    the last designator in the list.  */
4686
4687 struct constructor_range_stack
4688 {
4689   struct constructor_range_stack *next, *prev;
4690   struct constructor_stack *stack;
4691   tree range_start;
4692   tree index;
4693   tree range_end;
4694   tree fields;
4695 };
4696
4697 static struct constructor_range_stack *constructor_range_stack;
4698
4699 /* This stack records separate initializers that are nested.
4700    Nested initializers can't happen in ANSI C, but GNU C allows them
4701    in cases like { ... (struct foo) { ... } ... }.  */
4702
4703 struct initializer_stack
4704 {
4705   struct initializer_stack *next;
4706   tree decl;
4707   struct constructor_stack *constructor_stack;
4708   struct constructor_range_stack *constructor_range_stack;
4709   VEC(constructor_elt,gc) *elements;
4710   struct spelling *spelling;
4711   struct spelling *spelling_base;
4712   int spelling_size;
4713   char top_level;
4714   char require_constant_value;
4715   char require_constant_elements;
4716 };
4717
4718 static struct initializer_stack *initializer_stack;
4719 \f
4720 /* Prepare to parse and output the initializer for variable DECL.  */
4721
4722 void
4723 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4724 {
4725   const char *locus;
4726   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4727
4728   p->decl = constructor_decl;
4729   p->require_constant_value = require_constant_value;
4730   p->require_constant_elements = require_constant_elements;
4731   p->constructor_stack = constructor_stack;
4732   p->constructor_range_stack = constructor_range_stack;
4733   p->elements = constructor_elements;
4734   p->spelling = spelling;
4735   p->spelling_base = spelling_base;
4736   p->spelling_size = spelling_size;
4737   p->top_level = constructor_top_level;
4738   p->next = initializer_stack;
4739   initializer_stack = p;
4740
4741   constructor_decl = decl;
4742   constructor_designated = 0;
4743   constructor_top_level = top_level;
4744
4745   if (decl != 0 && decl != error_mark_node)
4746     {
4747       require_constant_value = TREE_STATIC (decl);
4748       require_constant_elements
4749         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4750            /* For a scalar, you can always use any value to initialize,
4751               even within braces.  */
4752            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4753                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4754                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4755                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4756       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4757     }
4758   else
4759     {
4760       require_constant_value = 0;
4761       require_constant_elements = 0;
4762       locus = "(anonymous)";
4763     }
4764
4765   constructor_stack = 0;
4766   constructor_range_stack = 0;
4767
4768   missing_braces_mentioned = 0;
4769
4770   spelling_base = 0;
4771   spelling_size = 0;
4772   RESTORE_SPELLING_DEPTH (0);
4773
4774   if (locus)
4775     push_string (locus);
4776 }
4777
4778 void
4779 finish_init (void)
4780 {
4781   struct initializer_stack *p = initializer_stack;
4782
4783   /* Free the whole constructor stack of this initializer.  */
4784   while (constructor_stack)
4785     {
4786       struct constructor_stack *q = constructor_stack;
4787       constructor_stack = q->next;
4788       free (q);
4789     }
4790
4791   gcc_assert (!constructor_range_stack);
4792
4793   /* Pop back to the data of the outer initializer (if any).  */
4794   free (spelling_base);
4795
4796   constructor_decl = p->decl;
4797   require_constant_value = p->require_constant_value;
4798   require_constant_elements = p->require_constant_elements;
4799   constructor_stack = p->constructor_stack;
4800   constructor_range_stack = p->constructor_range_stack;
4801   constructor_elements = p->elements;
4802   spelling = p->spelling;
4803   spelling_base = p->spelling_base;
4804   spelling_size = p->spelling_size;
4805   constructor_top_level = p->top_level;
4806   initializer_stack = p->next;
4807   free (p);
4808 }
4809 \f
4810 /* Call here when we see the initializer is surrounded by braces.
4811    This is instead of a call to push_init_level;
4812    it is matched by a call to pop_init_level.
4813
4814    TYPE is the type to initialize, for a constructor expression.
4815    For an initializer for a decl, TYPE is zero.  */
4816
4817 void
4818 really_start_incremental_init (tree type)
4819 {
4820   struct constructor_stack *p = XNEW (struct constructor_stack);
4821
4822   if (type == 0)
4823     type = TREE_TYPE (constructor_decl);
4824
4825   if (targetm.vector_opaque_p (type))
4826     error ("opaque vector types cannot be initialized");
4827
4828   p->type = constructor_type;
4829   p->fields = constructor_fields;
4830   p->index = constructor_index;
4831   p->max_index = constructor_max_index;
4832   p->unfilled_index = constructor_unfilled_index;
4833   p->unfilled_fields = constructor_unfilled_fields;
4834   p->bit_index = constructor_bit_index;
4835   p->elements = constructor_elements;
4836   p->constant = constructor_constant;
4837   p->simple = constructor_simple;
4838   p->erroneous = constructor_erroneous;
4839   p->pending_elts = constructor_pending_elts;
4840   p->depth = constructor_depth;
4841   p->replacement_value.value = 0;
4842   p->replacement_value.original_code = ERROR_MARK;
4843   p->implicit = 0;
4844   p->range_stack = 0;
4845   p->outer = 0;
4846   p->incremental = constructor_incremental;
4847   p->designated = constructor_designated;
4848   p->next = 0;
4849   constructor_stack = p;
4850
4851   constructor_constant = 1;
4852   constructor_simple = 1;
4853   constructor_depth = SPELLING_DEPTH ();
4854   constructor_elements = 0;
4855   constructor_pending_elts = 0;
4856   constructor_type = type;
4857   constructor_incremental = 1;
4858   constructor_designated = 0;
4859   designator_depth = 0;
4860   designator_errorneous = 0;
4861
4862   if (TREE_CODE (constructor_type) == RECORD_TYPE
4863       || TREE_CODE (constructor_type) == UNION_TYPE)
4864     {
4865       constructor_fields = TYPE_FIELDS (constructor_type);
4866       /* Skip any nameless bit fields at the beginning.  */
4867       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4868              && DECL_NAME (constructor_fields) == 0)
4869         constructor_fields = TREE_CHAIN (constructor_fields);
4870
4871       constructor_unfilled_fields = constructor_fields;
4872       constructor_bit_index = bitsize_zero_node;
4873     }
4874   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4875     {
4876       if (TYPE_DOMAIN (constructor_type))
4877         {
4878           constructor_max_index
4879             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4880
4881           /* Detect non-empty initializations of zero-length arrays.  */
4882           if (constructor_max_index == NULL_TREE
4883               && TYPE_SIZE (constructor_type))
4884             constructor_max_index = build_int_cst (NULL_TREE, -1);
4885
4886           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4887              to initialize VLAs will cause a proper error; avoid tree
4888              checking errors as well by setting a safe value.  */
4889           if (constructor_max_index
4890               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4891             constructor_max_index = build_int_cst (NULL_TREE, -1);
4892
4893           constructor_index
4894             = convert (bitsizetype,
4895                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4896         }
4897       else
4898         {
4899           constructor_index = bitsize_zero_node;
4900           constructor_max_index = NULL_TREE;
4901         }
4902
4903       constructor_unfilled_index = constructor_index;
4904     }
4905   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4906     {
4907       /* Vectors are like simple fixed-size arrays.  */
4908       constructor_max_index =
4909         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4910       constructor_index = convert (bitsizetype, bitsize_zero_node);
4911       constructor_unfilled_index = constructor_index;
4912     }
4913   else
4914     {
4915       /* Handle the case of int x = {5}; */
4916       constructor_fields = constructor_type;
4917       constructor_unfilled_fields = constructor_type;
4918     }
4919 }
4920 \f
4921 /* Push down into a subobject, for initialization.
4922    If this is for an explicit set of braces, IMPLICIT is 0.
4923    If it is because the next element belongs at a lower level,
4924    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4925
4926 void
4927 push_init_level (int implicit)
4928 {
4929   struct constructor_stack *p;
4930   tree value = NULL_TREE;
4931
4932   /* If we've exhausted any levels that didn't have braces,
4933      pop them now.  If implicit == 1, this will have been done in
4934      process_init_element; do not repeat it here because in the case
4935      of excess initializers for an empty aggregate this leads to an
4936      infinite cycle of popping a level and immediately recreating
4937      it.  */
4938   if (implicit != 1)
4939     {
4940       while (constructor_stack->implicit)
4941         {
4942           if ((TREE_CODE (constructor_type) == RECORD_TYPE
4943                || TREE_CODE (constructor_type) == UNION_TYPE)
4944               && constructor_fields == 0)
4945             process_init_element (pop_init_level (1));
4946           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4947                    && constructor_max_index
4948                    && tree_int_cst_lt (constructor_max_index,
4949                                        constructor_index))
4950             process_init_element (pop_init_level (1));
4951           else
4952             break;
4953         }
4954     }
4955
4956   /* Unless this is an explicit brace, we need to preserve previous
4957      content if any.  */
4958   if (implicit)
4959     {
4960       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4961            || TREE_CODE (constructor_type) == UNION_TYPE)
4962           && constructor_fields)
4963         value = find_init_member (constructor_fields);
4964       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4965         value = find_init_member (constructor_index);
4966     }
4967
4968   p = XNEW (struct constructor_stack);
4969   p->type = constructor_type;
4970   p->fields = constructor_fields;
4971   p->index = constructor_index;
4972   p->max_index = constructor_max_index;
4973   p->unfilled_index = constructor_unfilled_index;
4974   p->unfilled_fields = constructor_unfilled_fields;
4975   p->bit_index = constructor_bit_index;
4976   p->elements = constructor_elements;
4977   p->constant = constructor_constant;
4978   p->simple = constructor_simple;
4979   p->erroneous = constructor_erroneous;
4980   p->pending_elts = constructor_pending_elts;
4981   p->depth = constructor_depth;
4982   p->replacement_value.value = 0;
4983   p->replacement_value.original_code = ERROR_MARK;
4984   p->implicit = implicit;
4985   p->outer = 0;
4986   p->incremental = constructor_incremental;
4987   p->designated = constructor_designated;
4988   p->next = constructor_stack;
4989   p->range_stack = 0;
4990   constructor_stack = p;
4991
4992   constructor_constant = 1;
4993   constructor_simple = 1;
4994   constructor_depth = SPELLING_DEPTH ();
4995   constructor_elements = 0;
4996   constructor_incremental = 1;
4997   constructor_designated = 0;
4998   constructor_pending_elts = 0;
4999   if (!implicit)
5000     {
5001       p->range_stack = constructor_range_stack;
5002       constructor_range_stack = 0;
5003       designator_depth = 0;
5004       designator_errorneous = 0;
5005     }
5006
5007   /* Don't die if an entire brace-pair level is superfluous
5008      in the containing level.  */
5009   if (constructor_type == 0)
5010     ;
5011   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5012            || TREE_CODE (constructor_type) == UNION_TYPE)
5013     {
5014       /* Don't die if there are extra init elts at the end.  */
5015       if (constructor_fields == 0)
5016         constructor_type = 0;
5017       else
5018         {
5019           constructor_type = TREE_TYPE (constructor_fields);
5020           push_member_name (constructor_fields);
5021           constructor_depth++;
5022         }
5023     }
5024   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5025     {
5026       constructor_type = TREE_TYPE (constructor_type);
5027       push_array_bounds (tree_low_cst (constructor_index, 0));
5028       constructor_depth++;
5029     }
5030
5031   if (constructor_type == 0)
5032     {
5033       error_init ("extra brace group at end of initializer");
5034       constructor_fields = 0;
5035       constructor_unfilled_fields = 0;
5036       return;
5037     }
5038
5039   if (value && TREE_CODE (value) == CONSTRUCTOR)
5040     {
5041       constructor_constant = TREE_CONSTANT (value);
5042       constructor_simple = TREE_STATIC (value);
5043       constructor_elements = CONSTRUCTOR_ELTS (value);
5044       if (!VEC_empty (constructor_elt, constructor_elements)
5045           && (TREE_CODE (constructor_type) == RECORD_TYPE
5046               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5047         set_nonincremental_init ();
5048     }
5049
5050   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5051     {
5052       missing_braces_mentioned = 1;
5053       warning_init ("missing braces around initializer");
5054     }
5055
5056   if (TREE_CODE (constructor_type) == RECORD_TYPE
5057            || TREE_CODE (constructor_type) == UNION_TYPE)
5058     {
5059       constructor_fields = TYPE_FIELDS (constructor_type);
5060       /* Skip any nameless bit fields at the beginning.  */
5061       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5062              && DECL_NAME (constructor_fields) == 0)
5063         constructor_fields = TREE_CHAIN (constructor_fields);
5064
5065       constructor_unfilled_fields = constructor_fields;
5066       constructor_bit_index = bitsize_zero_node;
5067     }
5068   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5069     {
5070       /* Vectors are like simple fixed-size arrays.  */
5071       constructor_max_index =
5072         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5073       constructor_index = convert (bitsizetype, integer_zero_node);
5074       constructor_unfilled_index = constructor_index;
5075     }
5076   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5077     {
5078       if (TYPE_DOMAIN (constructor_type))
5079         {
5080           constructor_max_index
5081             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5082
5083           /* Detect non-empty initializations of zero-length arrays.  */
5084           if (constructor_max_index == NULL_TREE
5085               && TYPE_SIZE (constructor_type))
5086             constructor_max_index = build_int_cst (NULL_TREE, -1);
5087
5088           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5089              to initialize VLAs will cause a proper error; avoid tree
5090              checking errors as well by setting a safe value.  */
5091           if (constructor_max_index
5092               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5093             constructor_max_index = build_int_cst (NULL_TREE, -1);
5094
5095           constructor_index
5096             = convert (bitsizetype,
5097                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5098         }
5099       else
5100         constructor_index = bitsize_zero_node;
5101
5102       constructor_unfilled_index = constructor_index;
5103       if (value && TREE_CODE (value) == STRING_CST)
5104         {
5105           /* We need to split the char/wchar array into individual
5106              characters, so that we don't have to special case it
5107              everywhere.  */
5108           set_nonincremental_init_from_string (value);
5109         }
5110     }
5111   else
5112     {
5113       if (constructor_type != error_mark_node)
5114         warning_init ("braces around scalar initializer");
5115       constructor_fields = constructor_type;
5116       constructor_unfilled_fields = constructor_type;
5117     }
5118 }
5119
5120 /* At the end of an implicit or explicit brace level,
5121    finish up that level of constructor.  If a single expression
5122    with redundant braces initialized that level, return the
5123    c_expr structure for that expression.  Otherwise, the original_code
5124    element is set to ERROR_MARK.
5125    If we were outputting the elements as they are read, return 0 as the value
5126    from inner levels (process_init_element ignores that),
5127    but return error_mark_node as the value from the outermost level
5128    (that's what we want to put in DECL_INITIAL).
5129    Otherwise, return a CONSTRUCTOR expression as the value.  */
5130
5131 struct c_expr
5132 pop_init_level (int implicit)
5133 {
5134   struct constructor_stack *p;
5135   struct c_expr ret;
5136   ret.value = 0;
5137   ret.original_code = ERROR_MARK;
5138
5139   if (implicit == 0)
5140     {
5141       /* When we come to an explicit close brace,
5142          pop any inner levels that didn't have explicit braces.  */
5143       while (constructor_stack->implicit)
5144         process_init_element (pop_init_level (1));
5145
5146       gcc_assert (!constructor_range_stack);
5147     }
5148
5149   /* Now output all pending elements.  */
5150   constructor_incremental = 1;
5151   output_pending_init_elements (1);
5152
5153   p = constructor_stack;
5154
5155   /* Error for initializing a flexible array member, or a zero-length
5156      array member in an inappropriate context.  */
5157   if (constructor_type && constructor_fields
5158       && TREE_CODE (constructor_type) == ARRAY_TYPE
5159       && TYPE_DOMAIN (constructor_type)
5160       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5161     {
5162       /* Silently discard empty initializations.  The parser will
5163          already have pedwarned for empty brackets.  */
5164       if (integer_zerop (constructor_unfilled_index))
5165         constructor_type = NULL_TREE;
5166       else
5167         {
5168           gcc_assert (!TYPE_SIZE (constructor_type));
5169
5170           if (constructor_depth > 2)
5171             error_init ("initialization of flexible array member in a nested context");
5172           else if (pedantic)
5173             pedwarn_init ("initialization of a flexible array member");
5174
5175           /* We have already issued an error message for the existence
5176              of a flexible array member not at the end of the structure.
5177              Discard the initializer so that we do not die later.  */
5178           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5179             constructor_type = NULL_TREE;
5180         }
5181     }
5182
5183   /* Warn when some struct elements are implicitly initialized to zero.  */
5184   if (warn_missing_field_initializers
5185       && constructor_type
5186       && TREE_CODE (constructor_type) == RECORD_TYPE
5187       && constructor_unfilled_fields)
5188     {
5189         /* Do not warn for flexible array members or zero-length arrays.  */
5190         while (constructor_unfilled_fields
5191                && (!DECL_SIZE (constructor_unfilled_fields)
5192                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5193           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5194
5195         /* Do not warn if this level of the initializer uses member
5196            designators; it is likely to be deliberate.  */
5197         if (constructor_unfilled_fields && !constructor_designated)
5198           {
5199             push_member_name (constructor_unfilled_fields);
5200             warning_init ("missing initializer");
5201             RESTORE_SPELLING_DEPTH (constructor_depth);
5202           }
5203     }
5204
5205   /* Pad out the end of the structure.  */
5206   if (p->replacement_value.value)
5207     /* If this closes a superfluous brace pair,
5208        just pass out the element between them.  */
5209     ret = p->replacement_value;
5210   else if (constructor_type == 0)
5211     ;
5212   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5213            && TREE_CODE (constructor_type) != UNION_TYPE
5214            && TREE_CODE (constructor_type) != ARRAY_TYPE
5215            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5216     {
5217       /* A nonincremental scalar initializer--just return
5218          the element, after verifying there is just one.  */
5219       if (VEC_empty (constructor_elt,constructor_elements))
5220         {
5221           if (!constructor_erroneous)
5222             error_init ("empty scalar initializer");
5223           ret.value = error_mark_node;
5224         }
5225       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5226         {
5227           error_init ("extra elements in scalar initializer");
5228           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5229         }
5230       else
5231         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5232     }
5233   else
5234     {
5235       if (constructor_erroneous)
5236         ret.value = error_mark_node;
5237       else
5238         {
5239           ret.value = build_constructor (constructor_type,
5240                                          constructor_elements);
5241           if (constructor_constant)
5242             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5243           if (constructor_constant && constructor_simple)
5244             TREE_STATIC (ret.value) = 1;
5245         }
5246     }
5247
5248   constructor_type = p->type;
5249   constructor_fields = p->fields;
5250   constructor_index = p->index;
5251   constructor_max_index = p->max_index;
5252   constructor_unfilled_index = p->unfilled_index;
5253   constructor_unfilled_fields = p->unfilled_fields;
5254   constructor_bit_index = p->bit_index;
5255   constructor_elements = p->elements;
5256   constructor_constant = p->constant;
5257   constructor_simple = p->simple;
5258   constructor_erroneous = p->erroneous;
5259   constructor_incremental = p->incremental;
5260   constructor_designated = p->designated;
5261   constructor_pending_elts = p->pending_elts;
5262   constructor_depth = p->depth;
5263   if (!p->implicit)
5264     constructor_range_stack = p->range_stack;
5265   RESTORE_SPELLING_DEPTH (constructor_depth);
5266
5267   constructor_stack = p->next;
5268   free (p);
5269
5270   if (ret.value == 0)
5271     {
5272       if (constructor_stack == 0)
5273         {
5274           ret.value = error_mark_node;
5275           return ret;
5276         }
5277       return ret;
5278     }
5279   return ret;
5280 }
5281
5282 /* Common handling for both array range and field name designators.
5283    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5284
5285 static int
5286 set_designator (int array)
5287 {
5288   tree subtype;
5289   enum tree_code subcode;
5290
5291   /* Don't die if an entire brace-pair level is superfluous
5292      in the containing level.  */
5293   if (constructor_type == 0)
5294     return 1;
5295
5296   /* If there were errors in this designator list already, bail out
5297      silently.  */
5298   if (designator_errorneous)
5299     return 1;
5300
5301   if (!designator_depth)
5302     {
5303       gcc_assert (!constructor_range_stack);
5304
5305       /* Designator list starts at the level of closest explicit
5306          braces.  */
5307       while (constructor_stack->implicit)
5308         process_init_element (pop_init_level (1));
5309       constructor_designated = 1;
5310       return 0;
5311     }
5312
5313   switch (TREE_CODE (constructor_type))
5314     {
5315     case  RECORD_TYPE:
5316     case  UNION_TYPE:
5317       subtype = TREE_TYPE (constructor_fields);
5318       if (subtype != error_mark_node)
5319         subtype = TYPE_MAIN_VARIANT (subtype);
5320       break;
5321     case ARRAY_TYPE:
5322       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5323       break;
5324     default:
5325       gcc_unreachable ();
5326     }
5327
5328   subcode = TREE_CODE (subtype);
5329   if (array && subcode != ARRAY_TYPE)
5330     {
5331       error_init ("array index in non-array initializer");
5332       return 1;
5333     }
5334   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5335     {
5336       error_init ("field name not in record or union initializer");
5337       return 1;
5338     }
5339
5340   constructor_designated = 1;
5341   push_init_level (2);
5342   return 0;
5343 }
5344
5345 /* If there are range designators in designator list, push a new designator
5346    to constructor_range_stack.  RANGE_END is end of such stack range or
5347    NULL_TREE if there is no range designator at this level.  */
5348
5349 static void
5350 push_range_stack (tree range_end)
5351 {
5352   struct constructor_range_stack *p;
5353
5354   p = GGC_NEW (struct constructor_range_stack);
5355   p->prev = constructor_range_stack;
5356   p->next = 0;
5357   p->fields = constructor_fields;
5358   p->range_start = constructor_index;
5359   p->index = constructor_index;
5360   p->stack = constructor_stack;
5361   p->range_end = range_end;
5362   if (constructor_range_stack)
5363     constructor_range_stack->next = p;
5364   constructor_range_stack = p;
5365 }
5366
5367 /* Within an array initializer, specify the next index to be initialized.
5368    FIRST is that index.  If LAST is nonzero, then initialize a range
5369    of indices, running from FIRST through LAST.  */
5370
5371 void
5372 set_init_index (tree first, tree last)
5373 {
5374   if (set_designator (1))
5375     return;
5376
5377   designator_errorneous = 1;
5378
5379   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5380       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5381     {
5382       error_init ("array index in initializer not of integer type");
5383       return;
5384     }
5385
5386   if (TREE_CODE (first) != INTEGER_CST)
5387     error_init ("nonconstant array index in initializer");
5388   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5389     error_init ("nonconstant array index in initializer");
5390   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5391     error_init ("array index in non-array initializer");
5392   else if (tree_int_cst_sgn (first) == -1)
5393     error_init ("array index in initializer exceeds array bounds");
5394   else if (constructor_max_index
5395            && tree_int_cst_lt (constructor_max_index, first))
5396     error_init ("array index in initializer exceeds array bounds");
5397   else
5398     {
5399       constructor_index = convert (bitsizetype, first);
5400
5401       if (last)
5402         {
5403           if (tree_int_cst_equal (first, last))
5404             last = 0;
5405           else if (tree_int_cst_lt (last, first))
5406             {
5407               error_init ("empty index range in initializer");
5408               last = 0;
5409             }
5410           else
5411             {
5412               last = convert (bitsizetype, last);
5413               if (constructor_max_index != 0
5414                   && tree_int_cst_lt (constructor_max_index, last))
5415                 {
5416                   error_init ("array index range in initializer exceeds array bounds");
5417                   last = 0;
5418                 }
5419             }
5420         }
5421
5422       designator_depth++;
5423       designator_errorneous = 0;
5424       if (constructor_range_stack || last)
5425         push_range_stack (last);
5426     }
5427 }
5428
5429 /* Within a struct initializer, specify the next field to be initialized.  */
5430
5431 void
5432 set_init_label (tree fieldname)
5433 {
5434   tree tail;
5435
5436   if (set_designator (0))
5437     return;
5438
5439   designator_errorneous = 1;
5440
5441   if (TREE_CODE (constructor_type) != RECORD_TYPE
5442       && TREE_CODE (constructor_type) != UNION_TYPE)
5443     {
5444       error_init ("field name not in record or union initializer");
5445       return;
5446     }
5447
5448   for (tail = TYPE_FIELDS (constructor_type); tail;
5449        tail = TREE_CHAIN (tail))
5450     {
5451       if (DECL_NAME (tail) == fieldname)
5452         break;
5453     }
5454
5455   if (tail == 0)
5456     error ("unknown field %qE specified in initializer", fieldname);
5457   else
5458     {
5459       constructor_fields = tail;
5460       designator_depth++;
5461       designator_errorneous = 0;
5462       if (constructor_range_stack)
5463         push_range_stack (NULL_TREE);
5464     }
5465 }
5466 \f
5467 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5468    identifies the initializer, either array index or field in a structure.
5469    VALUE is the value of that index or field.  */
5470
5471 static void
5472 add_pending_init (tree purpose, tree value)
5473 {
5474   struct init_node *p, **q, *r;
5475
5476   q = &constructor_pending_elts;
5477   p = 0;
5478
5479   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5480     {
5481       while (*q != 0)
5482         {
5483           p = *q;
5484           if (tree_int_cst_lt (purpose, p->purpose))
5485             q = &p->left;
5486           else if (tree_int_cst_lt (p->purpose, purpose))
5487             q = &p->right;
5488           else
5489             {
5490               if (TREE_SIDE_EFFECTS (p->value))
5491                 warning_init ("initialized field with side-effects overwritten");
5492               p->value = value;
5493               return;
5494             }
5495         }
5496     }
5497   else
5498     {
5499       tree bitpos;
5500
5501       bitpos = bit_position (purpose);
5502       while (*q != NULL)
5503         {
5504           p = *q;
5505           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5506             q = &p->left;
5507           else if (p->purpose != purpose)
5508             q = &p->right;
5509           else
5510             {
5511               if (TREE_SIDE_EFFECTS (p->value))
5512                 warning_init ("initialized field with side-effects overwritten");
5513               p->value = value;
5514               return;
5515             }
5516         }
5517     }
5518
5519   r = GGC_NEW (struct init_node);
5520   r->purpose = purpose;
5521   r->value = value;
5522
5523   *q = r;
5524   r->parent = p;
5525   r->left = 0;
5526   r->right = 0;
5527   r->balance = 0;
5528
5529   while (p)
5530     {
5531       struct init_node *s;
5532
5533       if (r == p->left)
5534         {
5535           if (p->balance == 0)
5536             p->balance = -1;
5537           else if (p->balance < 0)
5538             {
5539               if (r->balance < 0)
5540                 {
5541                   /* L rotation.  */
5542                   p->left = r->right;
5543                   if (p->left)
5544                     p->left->parent = p;
5545                   r->right = p;
5546
5547                   p->balance = 0;
5548                   r->balance = 0;
5549
5550                   s = p->parent;
5551                   p->parent = r;
5552                   r->parent = s;
5553                   if (s)
5554                     {
5555                       if (s->left == p)
5556                         s->left = r;
5557                       else
5558                         s->right = r;
5559                     }
5560                   else
5561                     constructor_pending_elts = r;
5562                 }
5563               else
5564                 {
5565                   /* LR rotation.  */
5566                   struct init_node *t = r->right;
5567
5568                   r->right = t->left;
5569                   if (r->right)
5570                     r->right->parent = r;
5571                   t->left = r;
5572
5573                   p->left = t->right;
5574                   if (p->left)
5575                     p->left->parent = p;
5576                   t->right = p;
5577
5578                   p->balance = t->balance < 0;
5579                   r->balance = -(t->balance > 0);
5580                   t->balance = 0;
5581
5582                   s = p->parent;
5583                   p->parent = t;
5584                   r->parent = t;
5585                   t->parent = s;
5586                   if (s)
5587                     {
5588                       if (s->left == p)
5589                         s->left = t;
5590                       else
5591                         s->right = t;
5592                     }
5593                   else
5594                     constructor_pending_elts = t;
5595                 }
5596               break;
5597             }
5598           else
5599             {
5600               /* p->balance == +1; growth of left side balances the node.  */
5601               p->balance = 0;
5602               break;
5603             }
5604         }
5605       else /* r == p->right */
5606         {
5607           if (p->balance == 0)
5608             /* Growth propagation from right side.  */
5609             p->balance++;
5610           else if (p->balance > 0)
5611             {
5612               if (r->balance > 0)
5613                 {
5614                   /* R rotation.  */
5615                   p->right = r->left;
5616                   if (p->right)
5617                     p->right->parent = p;
5618                   r->left = p;
5619
5620                   p->balance = 0;
5621                   r->balance = 0;
5622
5623                   s = p->parent;
5624                   p->parent = r;
5625                   r->parent = s;
5626                   if (s)
5627                     {
5628                       if (s->left == p)
5629                         s->left = r;
5630                       else
5631                         s->right = r;
5632                     }
5633                   else
5634                     constructor_pending_elts = r;
5635                 }
5636               else /* r->balance == -1 */
5637                 {
5638                   /* RL rotation */
5639                   struct init_node *t = r->left;
5640
5641                   r->left = t->right;
5642                   if (r->left)
5643                     r->left->parent = r;
5644                   t->right = r;
5645
5646                   p->right = t->left;
5647                   if (p->right)
5648                     p->right->parent = p;
5649                   t->left = p;
5650
5651                   r->balance = (t->balance < 0);
5652                   p->balance = -(t->balance > 0);
5653                   t->balance = 0;
5654
5655                   s = p->parent;
5656                   p->parent = t;
5657                   r->parent = t;
5658                   t->parent = s;
5659                   if (s)
5660                     {
5661                       if (s->left == p)
5662                         s->left = t;
5663                       else
5664                         s->right = t;
5665                     }
5666                   else
5667                     constructor_pending_elts = t;
5668                 }
5669               break;
5670             }
5671           else
5672             {
5673               /* p->balance == -1; growth of right side balances the node.  */
5674               p->balance = 0;
5675               break;
5676             }
5677         }
5678
5679       r = p;
5680       p = p->parent;
5681     }
5682 }
5683
5684 /* Build AVL tree from a sorted chain.  */
5685
5686 static void
5687 set_nonincremental_init (void)
5688 {
5689   unsigned HOST_WIDE_INT ix;
5690   tree index, value;
5691
5692   if (TREE_CODE (constructor_type) != RECORD_TYPE
5693       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5694     return;
5695
5696   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5697     add_pending_init (index, value);
5698   constructor_elements = 0;
5699   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5700     {
5701       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5702       /* Skip any nameless bit fields at the beginning.  */
5703       while (constructor_unfilled_fields != 0
5704              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5705              && DECL_NAME (constructor_unfilled_fields) == 0)
5706         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5707
5708     }
5709   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5710     {
5711       if (TYPE_DOMAIN (constructor_type))
5712         constructor_unfilled_index
5713             = convert (bitsizetype,
5714                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5715       else
5716         constructor_unfilled_index = bitsize_zero_node;
5717     }
5718   constructor_incremental = 0;
5719 }
5720
5721 /* Build AVL tree from a string constant.  */
5722
5723 static void
5724 set_nonincremental_init_from_string (tree str)
5725 {
5726   tree value, purpose, type;
5727   HOST_WIDE_INT val[2];
5728   const char *p, *end;
5729   int byte, wchar_bytes, charwidth, bitpos;
5730
5731   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5732
5733   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5734       == TYPE_PRECISION (char_type_node))
5735     wchar_bytes = 1;
5736   else
5737     {
5738       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5739                   == TYPE_PRECISION (wchar_type_node));
5740       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5741     }
5742   charwidth = TYPE_PRECISION (char_type_node);
5743   type = TREE_TYPE (constructor_type);
5744   p = TREE_STRING_POINTER (str);
5745   end = p + TREE_STRING_LENGTH (str);
5746
5747   for (purpose = bitsize_zero_node;
5748        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5749        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5750     {
5751       if (wchar_bytes == 1)
5752         {
5753           val[1] = (unsigned char) *p++;
5754           val[0] = 0;
5755         }
5756       else
5757         {
5758           val[0] = 0;
5759           val[1] = 0;
5760           for (byte = 0; byte < wchar_bytes; byte++)
5761             {
5762               if (BYTES_BIG_ENDIAN)
5763                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5764               else
5765                 bitpos = byte * charwidth;
5766               val[bitpos < HOST_BITS_PER_WIDE_INT]
5767                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5768                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5769             }
5770         }
5771
5772       if (!TYPE_UNSIGNED (type))
5773         {
5774           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5775           if (bitpos < HOST_BITS_PER_WIDE_INT)
5776             {
5777               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5778                 {
5779                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5780                   val[0] = -1;
5781                 }
5782             }
5783           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5784             {
5785               if (val[1] < 0)
5786                 val[0] = -1;
5787             }
5788           else if (val[0] & (((HOST_WIDE_INT) 1)
5789                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5790             val[0] |= ((HOST_WIDE_INT) -1)
5791                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5792         }
5793
5794       value = build_int_cst_wide (type, val[1], val[0]);
5795       add_pending_init (purpose, value);
5796     }
5797
5798   constructor_incremental = 0;
5799 }
5800
5801 /* Return value of FIELD in pending initializer or zero if the field was
5802    not initialized yet.  */
5803
5804 static tree
5805 find_init_member (tree field)
5806 {
5807   struct init_node *p;
5808
5809   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5810     {
5811       if (constructor_incremental
5812           && tree_int_cst_lt (field, constructor_unfilled_index))
5813         set_nonincremental_init ();
5814
5815       p = constructor_pending_elts;
5816       while (p)
5817         {
5818           if (tree_int_cst_lt (field, p->purpose))
5819             p = p->left;
5820           else if (tree_int_cst_lt (p->purpose, field))
5821             p = p->right;
5822           else
5823             return p->value;
5824         }
5825     }
5826   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5827     {
5828       tree bitpos = bit_position (field);
5829
5830       if (constructor_incremental
5831           && (!constructor_unfilled_fields
5832               || tree_int_cst_lt (bitpos,
5833                                   bit_position (constructor_unfilled_fields))))
5834         set_nonincremental_init ();
5835
5836       p = constructor_pending_elts;
5837       while (p)
5838         {
5839           if (field == p->purpose)
5840             return p->value;
5841           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5842             p = p->left;
5843           else
5844             p = p->right;
5845         }
5846     }
5847   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5848     {
5849       if (!VEC_empty (constructor_elt, constructor_elements)
5850           && (VEC_last (constructor_elt, constructor_elements)->index
5851               == field))
5852         return VEC_last (constructor_elt, constructor_elements)->value;
5853     }
5854   return 0;
5855 }
5856
5857 /* "Output" the next constructor element.
5858    At top level, really output it to assembler code now.
5859    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5860    TYPE is the data type that the containing data type wants here.
5861    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5862    If VALUE is a string constant, STRICT_STRING is true if it is
5863    unparenthesized or we should not warn here for it being parenthesized.
5864    For other types of VALUE, STRICT_STRING is not used.
5865
5866    PENDING if non-nil means output pending elements that belong
5867    right after this element.  (PENDING is normally 1;
5868    it is 0 while outputting pending elements, to avoid recursion.)  */
5869
5870 static void
5871 output_init_element (tree value, bool strict_string, tree type, tree field,
5872                      int pending)
5873 {
5874   constructor_elt *celt;
5875
5876   if (type == error_mark_node || value == error_mark_node)
5877     {
5878       constructor_erroneous = 1;
5879       return;
5880     }
5881   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5882       && (TREE_CODE (value) == STRING_CST
5883           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5884       && !(TREE_CODE (value) == STRING_CST
5885            && TREE_CODE (type) == ARRAY_TYPE
5886            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5887       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5888                      TYPE_MAIN_VARIANT (type)))
5889     value = array_to_pointer_conversion (value);
5890
5891   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5892       && require_constant_value && !flag_isoc99 && pending)
5893     {
5894       /* As an extension, allow initializing objects with static storage
5895          duration with compound literals (which are then treated just as
5896          the brace enclosed list they contain).  */
5897       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5898       value = DECL_INITIAL (decl);
5899     }
5900
5901   if (value == error_mark_node)
5902     constructor_erroneous = 1;
5903   else if (!TREE_CONSTANT (value))
5904     constructor_constant = 0;
5905   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
5906            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5907                 || TREE_CODE (constructor_type) == UNION_TYPE)
5908                && DECL_C_BIT_FIELD (field)
5909                && TREE_CODE (value) != INTEGER_CST))
5910     constructor_simple = 0;
5911
5912   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
5913     {
5914       if (require_constant_value)
5915         {
5916           error_init ("initializer element is not constant");
5917           value = error_mark_node;
5918         }
5919       else if (require_constant_elements)
5920         pedwarn ("initializer element is not computable at load time");
5921     }
5922
5923   /* If this field is empty (and not at the end of structure),
5924      don't do anything other than checking the initializer.  */
5925   if (field
5926       && (TREE_TYPE (field) == error_mark_node
5927           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5928               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5929               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5930                   || TREE_CHAIN (field)))))
5931     return;
5932
5933   value = digest_init (type, value, strict_string, require_constant_value);
5934   if (value == error_mark_node)
5935     {
5936       constructor_erroneous = 1;
5937       return;
5938     }
5939
5940   /* If this element doesn't come next in sequence,
5941      put it on constructor_pending_elts.  */
5942   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5943       && (!constructor_incremental
5944           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5945     {
5946       if (constructor_incremental
5947           && tree_int_cst_lt (field, constructor_unfilled_index))
5948         set_nonincremental_init ();
5949
5950       add_pending_init (field, value);
5951       return;
5952     }
5953   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5954            && (!constructor_incremental
5955                || field != constructor_unfilled_fields))
5956     {
5957       /* We do this for records but not for unions.  In a union,
5958          no matter which field is specified, it can be initialized
5959          right away since it starts at the beginning of the union.  */
5960       if (constructor_incremental)
5961         {
5962           if (!constructor_unfilled_fields)
5963             set_nonincremental_init ();
5964           else
5965             {
5966               tree bitpos, unfillpos;
5967
5968               bitpos = bit_position (field);
5969               unfillpos = bit_position (constructor_unfilled_fields);
5970
5971               if (tree_int_cst_lt (bitpos, unfillpos))
5972                 set_nonincremental_init ();
5973             }
5974         }
5975
5976       add_pending_init (field, value);
5977       return;
5978     }
5979   else if (TREE_CODE (constructor_type) == UNION_TYPE
5980            && !VEC_empty (constructor_elt, constructor_elements))
5981     {
5982       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
5983                                        constructor_elements)->value))
5984         warning_init ("initialized field with side-effects overwritten");
5985
5986       /* We can have just one union field set.  */
5987       constructor_elements = 0;
5988     }
5989
5990   /* Otherwise, output this element either to
5991      constructor_elements or to the assembler file.  */
5992
5993   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
5994   celt->index = field;
5995   celt->value = value;
5996
5997   /* Advance the variable that indicates sequential elements output.  */
5998   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5999     constructor_unfilled_index
6000       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6001                     bitsize_one_node);
6002   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6003     {
6004       constructor_unfilled_fields
6005         = TREE_CHAIN (constructor_unfilled_fields);
6006
6007       /* Skip any nameless bit fields.  */
6008       while (constructor_unfilled_fields != 0
6009              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6010              && DECL_NAME (constructor_unfilled_fields) == 0)
6011         constructor_unfilled_fields =
6012           TREE_CHAIN (constructor_unfilled_fields);
6013     }
6014   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6015     constructor_unfilled_fields = 0;
6016
6017   /* Now output any pending elements which have become next.  */
6018   if (pending)
6019     output_pending_init_elements (0);
6020 }
6021
6022 /* Output any pending elements which have become next.
6023    As we output elements, constructor_unfilled_{fields,index}
6024    advances, which may cause other elements to become next;
6025    if so, they too are output.
6026
6027    If ALL is 0, we return when there are
6028    no more pending elements to output now.
6029
6030    If ALL is 1, we output space as necessary so that
6031    we can output all the pending elements.  */
6032
6033 static void
6034 output_pending_init_elements (int all)
6035 {
6036   struct init_node *elt = constructor_pending_elts;
6037   tree next;
6038
6039  retry:
6040
6041   /* Look through the whole pending tree.
6042      If we find an element that should be output now,
6043      output it.  Otherwise, set NEXT to the element
6044      that comes first among those still pending.  */
6045
6046   next = 0;
6047   while (elt)
6048     {
6049       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6050         {
6051           if (tree_int_cst_equal (elt->purpose,
6052                                   constructor_unfilled_index))
6053             output_init_element (elt->value, true,
6054                                  TREE_TYPE (constructor_type),
6055                                  constructor_unfilled_index, 0);
6056           else if (tree_int_cst_lt (constructor_unfilled_index,
6057                                     elt->purpose))
6058             {
6059               /* Advance to the next smaller node.  */
6060               if (elt->left)
6061                 elt = elt->left;
6062               else
6063                 {
6064                   /* We have reached the smallest node bigger than the
6065                      current unfilled index.  Fill the space first.  */
6066                   next = elt->purpose;
6067                   break;
6068                 }
6069             }
6070           else
6071             {
6072               /* Advance to the next bigger node.  */
6073               if (elt->right)
6074                 elt = elt->right;
6075               else
6076                 {
6077                   /* We have reached the biggest node in a subtree.  Find
6078                      the parent of it, which is the next bigger node.  */
6079                   while (elt->parent && elt->parent->right == elt)
6080                     elt = elt->parent;
6081                   elt = elt->parent;
6082                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6083                                               elt->purpose))
6084                     {
6085                       next = elt->purpose;
6086                       break;
6087                     }
6088                 }
6089             }
6090         }
6091       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6092                || TREE_CODE (constructor_type) == UNION_TYPE)
6093         {
6094           tree ctor_unfilled_bitpos, elt_bitpos;
6095
6096           /* If the current record is complete we are done.  */
6097           if (constructor_unfilled_fields == 0)
6098             break;
6099
6100           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6101           elt_bitpos = bit_position (elt->purpose);
6102           /* We can't compare fields here because there might be empty
6103              fields in between.  */
6104           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6105             {
6106               constructor_unfilled_fields = elt->purpose;
6107               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6108                                    elt->purpose, 0);
6109             }
6110           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6111             {
6112               /* Advance to the next smaller node.  */
6113               if (elt->left)
6114                 elt = elt->left;
6115               else
6116                 {
6117                   /* We have reached the smallest node bigger than the
6118                      current unfilled field.  Fill the space first.  */
6119                   next = elt->purpose;
6120                   break;
6121                 }
6122             }
6123           else
6124             {
6125               /* Advance to the next bigger node.  */
6126               if (elt->right)
6127                 elt = elt->right;
6128               else
6129                 {
6130                   /* We have reached the biggest node in a subtree.  Find
6131                      the parent of it, which is the next bigger node.  */
6132                   while (elt->parent && elt->parent->right == elt)
6133                     elt = elt->parent;
6134                   elt = elt->parent;
6135                   if (elt
6136                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6137                                            bit_position (elt->purpose))))
6138                     {
6139                       next = elt->purpose;
6140                       break;
6141                     }
6142                 }
6143             }
6144         }
6145     }
6146
6147   /* Ordinarily return, but not if we want to output all
6148      and there are elements left.  */
6149   if (!(all && next != 0))
6150     return;
6151
6152   /* If it's not incremental, just skip over the gap, so that after
6153      jumping to retry we will output the next successive element.  */
6154   if (TREE_CODE (constructor_type) == RECORD_TYPE
6155       || TREE_CODE (constructor_type) == UNION_TYPE)
6156     constructor_unfilled_fields = next;
6157   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6158     constructor_unfilled_index = next;
6159
6160   /* ELT now points to the node in the pending tree with the next
6161      initializer to output.  */
6162   goto retry;
6163 }
6164 \f
6165 /* Add one non-braced element to the current constructor level.
6166    This adjusts the current position within the constructor's type.
6167    This may also start or terminate implicit levels
6168    to handle a partly-braced initializer.
6169
6170    Once this has found the correct level for the new element,
6171    it calls output_init_element.  */
6172
6173 void
6174 process_init_element (struct c_expr value)
6175 {
6176   tree orig_value = value.value;
6177   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6178   bool strict_string = value.original_code == STRING_CST;
6179
6180   designator_depth = 0;
6181   designator_errorneous = 0;
6182
6183   /* Handle superfluous braces around string cst as in
6184      char x[] = {"foo"}; */
6185   if (string_flag
6186       && constructor_type
6187       && TREE_CODE (constructor_type) == ARRAY_TYPE
6188       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6189       && integer_zerop (constructor_unfilled_index))
6190     {
6191       if (constructor_stack->replacement_value.value)
6192         error_init ("excess elements in char array initializer");
6193       constructor_stack->replacement_value = value;
6194       return;
6195     }
6196
6197   if (constructor_stack->replacement_value.value != 0)
6198     {
6199       error_init ("excess elements in struct initializer");
6200       return;
6201     }
6202
6203   /* Ignore elements of a brace group if it is entirely superfluous
6204      and has already been diagnosed.  */
6205   if (constructor_type == 0)
6206     return;
6207
6208   /* If we've exhausted any levels that didn't have braces,
6209      pop them now.  */
6210   while (constructor_stack->implicit)
6211     {
6212       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6213            || TREE_CODE (constructor_type) == UNION_TYPE)
6214           && constructor_fields == 0)
6215         process_init_element (pop_init_level (1));
6216       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6217                && (constructor_max_index == 0
6218                    || tree_int_cst_lt (constructor_max_index,
6219                                        constructor_index)))
6220         process_init_element (pop_init_level (1));
6221       else
6222         break;
6223     }
6224
6225   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6226   if (constructor_range_stack)
6227     {
6228       /* If value is a compound literal and we'll be just using its
6229          content, don't put it into a SAVE_EXPR.  */
6230       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6231           || !require_constant_value
6232           || flag_isoc99)
6233         value.value = save_expr (value.value);
6234     }
6235
6236   while (1)
6237     {
6238       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6239         {
6240           tree fieldtype;
6241           enum tree_code fieldcode;
6242
6243           if (constructor_fields == 0)
6244             {
6245               pedwarn_init ("excess elements in struct initializer");
6246               break;
6247             }
6248
6249           fieldtype = TREE_TYPE (constructor_fields);
6250           if (fieldtype != error_mark_node)
6251             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6252           fieldcode = TREE_CODE (fieldtype);
6253
6254           /* Error for non-static initialization of a flexible array member.  */
6255           if (fieldcode == ARRAY_TYPE
6256               && !require_constant_value
6257               && TYPE_SIZE (fieldtype) == NULL_TREE
6258               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6259             {
6260               error_init ("non-static initialization of a flexible array member");
6261               break;
6262             }
6263
6264           /* Accept a string constant to initialize a subarray.  */
6265           if (value.value != 0
6266               && fieldcode == ARRAY_TYPE
6267               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6268               && string_flag)
6269             value.value = orig_value;
6270           /* Otherwise, if we have come to a subaggregate,
6271              and we don't have an element of its type, push into it.  */
6272           else if (value.value != 0
6273                    && value.value != error_mark_node
6274                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6275                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6276                        || fieldcode == UNION_TYPE))
6277             {
6278               push_init_level (1);
6279               continue;
6280             }
6281
6282           if (value.value)
6283             {
6284               push_member_name (constructor_fields);
6285               output_init_element (value.value, strict_string,
6286                                    fieldtype, constructor_fields, 1);
6287               RESTORE_SPELLING_DEPTH (constructor_depth);
6288             }
6289           else
6290             /* Do the bookkeeping for an element that was
6291                directly output as a constructor.  */
6292             {
6293               /* For a record, keep track of end position of last field.  */
6294               if (DECL_SIZE (constructor_fields))
6295                 constructor_bit_index
6296                   = size_binop (PLUS_EXPR,
6297                                 bit_position (constructor_fields),
6298                                 DECL_SIZE (constructor_fields));
6299
6300               /* If the current field was the first one not yet written out,
6301                  it isn't now, so update.  */
6302               if (constructor_unfilled_fields == constructor_fields)
6303                 {
6304                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6305                   /* Skip any nameless bit fields.  */
6306                   while (constructor_unfilled_fields != 0
6307                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6308                          && DECL_NAME (constructor_unfilled_fields) == 0)
6309                     constructor_unfilled_fields =
6310                       TREE_CHAIN (constructor_unfilled_fields);
6311                 }
6312             }
6313
6314           constructor_fields = TREE_CHAIN (constructor_fields);
6315           /* Skip any nameless bit fields at the beginning.  */
6316           while (constructor_fields != 0
6317                  && DECL_C_BIT_FIELD (constructor_fields)
6318                  && DECL_NAME (constructor_fields) == 0)
6319             constructor_fields = TREE_CHAIN (constructor_fields);
6320         }
6321       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6322         {
6323           tree fieldtype;
6324           enum tree_code fieldcode;
6325
6326           if (constructor_fields == 0)
6327             {
6328               pedwarn_init ("excess elements in union initializer");
6329               break;
6330             }
6331
6332           fieldtype = TREE_TYPE (constructor_fields);
6333           if (fieldtype != error_mark_node)
6334             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6335           fieldcode = TREE_CODE (fieldtype);
6336
6337           /* Warn that traditional C rejects initialization of unions.
6338              We skip the warning if the value is zero.  This is done
6339              under the assumption that the zero initializer in user
6340              code appears conditioned on e.g. __STDC__ to avoid
6341              "missing initializer" warnings and relies on default
6342              initialization to zero in the traditional C case.
6343              We also skip the warning if the initializer is designated,
6344              again on the assumption that this must be conditional on
6345              __STDC__ anyway (and we've already complained about the
6346              member-designator already).  */
6347           if (!in_system_header && !constructor_designated
6348               && !(value.value && (integer_zerop (value.value)
6349                                    || real_zerop (value.value))))
6350             warning (OPT_Wtraditional, "traditional C rejects initialization "
6351                      "of unions");
6352
6353           /* Accept a string constant to initialize a subarray.  */
6354           if (value.value != 0
6355               && fieldcode == ARRAY_TYPE
6356               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6357               && string_flag)
6358             value.value = orig_value;
6359           /* Otherwise, if we have come to a subaggregate,
6360              and we don't have an element of its type, push into it.  */
6361           else if (value.value != 0
6362                    && value.value != error_mark_node
6363                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6364                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6365                        || fieldcode == UNION_TYPE))
6366             {
6367               push_init_level (1);
6368               continue;
6369             }
6370
6371           if (value.value)
6372             {
6373               push_member_name (constructor_fields);
6374               output_init_element (value.value, strict_string,
6375                                    fieldtype, constructor_fields, 1);
6376               RESTORE_SPELLING_DEPTH (constructor_depth);
6377             }
6378           else
6379             /* Do the bookkeeping for an element that was
6380                directly output as a constructor.  */
6381             {
6382               constructor_bit_index = DECL_SIZE (constructor_fields);
6383               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6384             }
6385
6386           constructor_fields = 0;
6387         }
6388       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6389         {
6390           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6391           enum tree_code eltcode = TREE_CODE (elttype);
6392
6393           /* Accept a string constant to initialize a subarray.  */
6394           if (value.value != 0
6395               && eltcode == ARRAY_TYPE
6396               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6397               && string_flag)
6398             value.value = orig_value;
6399           /* Otherwise, if we have come to a subaggregate,
6400              and we don't have an element of its type, push into it.  */
6401           else if (value.value != 0
6402                    && value.value != error_mark_node
6403                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6404                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6405                        || eltcode == UNION_TYPE))
6406             {
6407               push_init_level (1);
6408               continue;
6409             }
6410
6411           if (constructor_max_index != 0
6412               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6413                   || integer_all_onesp (constructor_max_index)))
6414             {
6415               pedwarn_init ("excess elements in array initializer");
6416               break;
6417             }
6418
6419           /* Now output the actual element.  */
6420           if (value.value)
6421             {
6422               push_array_bounds (tree_low_cst (constructor_index, 0));
6423               output_init_element (value.value, strict_string,
6424                                    elttype, constructor_index, 1);
6425               RESTORE_SPELLING_DEPTH (constructor_depth);
6426             }
6427
6428           constructor_index
6429             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6430
6431           if (!value.value)
6432             /* If we are doing the bookkeeping for an element that was
6433                directly output as a constructor, we must update
6434                constructor_unfilled_index.  */
6435             constructor_unfilled_index = constructor_index;
6436         }
6437       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6438         {
6439           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6440
6441          /* Do a basic check of initializer size.  Note that vectors
6442             always have a fixed size derived from their type.  */
6443           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6444             {
6445               pedwarn_init ("excess elements in vector initializer");
6446               break;
6447             }
6448
6449           /* Now output the actual element.  */
6450           if (value.value)
6451             output_init_element (value.value, strict_string,
6452                                  elttype, constructor_index, 1);
6453
6454           constructor_index
6455             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6456
6457           if (!value.value)
6458             /* If we are doing the bookkeeping for an element that was
6459                directly output as a constructor, we must update
6460                constructor_unfilled_index.  */
6461             constructor_unfilled_index = constructor_index;
6462         }
6463
6464       /* Handle the sole element allowed in a braced initializer
6465          for a scalar variable.  */
6466       else if (constructor_type != error_mark_node
6467                && constructor_fields == 0)
6468         {
6469           pedwarn_init ("excess elements in scalar initializer");
6470           break;
6471         }
6472       else
6473         {
6474           if (value.value)
6475             output_init_element (value.value, strict_string,
6476                                  constructor_type, NULL_TREE, 1);
6477           constructor_fields = 0;
6478         }
6479
6480       /* Handle range initializers either at this level or anywhere higher
6481          in the designator stack.  */
6482       if (constructor_range_stack)
6483         {
6484           struct constructor_range_stack *p, *range_stack;
6485           int finish = 0;
6486
6487           range_stack = constructor_range_stack;
6488           constructor_range_stack = 0;
6489           while (constructor_stack != range_stack->stack)
6490             {
6491               gcc_assert (constructor_stack->implicit);
6492               process_init_element (pop_init_level (1));
6493             }
6494           for (p = range_stack;
6495                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6496                p = p->prev)
6497             {
6498               gcc_assert (constructor_stack->implicit);
6499               process_init_element (pop_init_level (1));
6500             }
6501
6502           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6503           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6504             finish = 1;
6505
6506           while (1)
6507             {
6508               constructor_index = p->index;
6509               constructor_fields = p->fields;
6510               if (finish && p->range_end && p->index == p->range_start)
6511                 {
6512                   finish = 0;
6513                   p->prev = 0;
6514                 }
6515               p = p->next;
6516               if (!p)
6517                 break;
6518               push_init_level (2);
6519               p->stack = constructor_stack;
6520               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6521                 p->index = p->range_start;
6522             }
6523
6524           if (!finish)
6525             constructor_range_stack = range_stack;
6526           continue;
6527         }
6528
6529       break;
6530     }
6531
6532   constructor_range_stack = 0;
6533 }
6534 \f
6535 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6536    (guaranteed to be 'volatile' or null) and ARGS (represented using
6537    an ASM_EXPR node).  */
6538 tree
6539 build_asm_stmt (tree cv_qualifier, tree args)
6540 {
6541   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6542     ASM_VOLATILE_P (args) = 1;
6543   return add_stmt (args);
6544 }
6545
6546 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6547    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6548    SIMPLE indicates whether there was anything at all after the
6549    string in the asm expression -- asm("blah") and asm("blah" : )
6550    are subtly different.  We use a ASM_EXPR node to represent this.  */
6551 tree
6552 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6553                 bool simple)
6554 {
6555   tree tail;
6556   tree args;
6557   int i;
6558   const char *constraint;
6559   const char **oconstraints;
6560   bool allows_mem, allows_reg, is_inout;
6561   int ninputs, noutputs;
6562
6563   ninputs = list_length (inputs);
6564   noutputs = list_length (outputs);
6565   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6566
6567   string = resolve_asm_operand_names (string, outputs, inputs);
6568
6569   /* Remove output conversions that change the type but not the mode.  */
6570   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6571     {
6572       tree output = TREE_VALUE (tail);
6573
6574       /* ??? Really, this should not be here.  Users should be using a
6575          proper lvalue, dammit.  But there's a long history of using casts
6576          in the output operands.  In cases like longlong.h, this becomes a
6577          primitive form of typechecking -- if the cast can be removed, then
6578          the output operand had a type of the proper width; otherwise we'll
6579          get an error.  Gross, but ...  */
6580       STRIP_NOPS (output);
6581
6582       if (!lvalue_or_else (output, lv_asm))
6583         output = error_mark_node;
6584
6585       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6586       oconstraints[i] = constraint;
6587
6588       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6589                                    &allows_mem, &allows_reg, &is_inout))
6590         {
6591           /* If the operand is going to end up in memory,
6592              mark it addressable.  */
6593           if (!allows_reg && !c_mark_addressable (output))
6594             output = error_mark_node;
6595         }
6596       else
6597         output = error_mark_node;
6598
6599       TREE_VALUE (tail) = output;
6600     }
6601
6602   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6603     {
6604       tree input;
6605
6606       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6607       input = TREE_VALUE (tail);
6608
6609       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6610                                   oconstraints, &allows_mem, &allows_reg))
6611         {
6612           /* If the operand is going to end up in memory,
6613              mark it addressable.  */
6614           if (!allows_reg && allows_mem)
6615             {
6616               /* Strip the nops as we allow this case.  FIXME, this really
6617                  should be rejected or made deprecated.  */
6618               STRIP_NOPS (input);
6619               if (!c_mark_addressable (input))
6620                 input = error_mark_node;
6621           }
6622         }
6623       else
6624         input = error_mark_node;
6625
6626       TREE_VALUE (tail) = input;
6627     }
6628
6629   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6630
6631   /* Simple asm statements are treated as volatile.  */
6632   if (simple)
6633     {
6634       ASM_VOLATILE_P (args) = 1;
6635       ASM_INPUT_P (args) = 1;
6636     }
6637
6638   return args;
6639 }
6640 \f
6641 /* Generate a goto statement to LABEL.  */
6642
6643 tree
6644 c_finish_goto_label (tree label)
6645 {
6646   tree decl = lookup_label (label);
6647   if (!decl)
6648     return NULL_TREE;
6649
6650   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6651     {
6652       error ("jump into statement expression");
6653       return NULL_TREE;
6654     }
6655
6656   if (C_DECL_UNJUMPABLE_VM (decl))
6657     {
6658       error ("jump into scope of identifier with variably modified type");
6659       return NULL_TREE;
6660     }
6661
6662   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6663     {
6664       /* No jump from outside this statement expression context, so
6665          record that there is a jump from within this context.  */
6666       struct c_label_list *nlist;
6667       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6668       nlist->next = label_context_stack_se->labels_used;
6669       nlist->label = decl;
6670       label_context_stack_se->labels_used = nlist;
6671     }
6672
6673   if (!C_DECL_UNDEFINABLE_VM (decl))
6674     {
6675       /* No jump from outside this context context of identifiers with
6676          variably modified type, so record that there is a jump from
6677          within this context.  */
6678       struct c_label_list *nlist;
6679       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6680       nlist->next = label_context_stack_vm->labels_used;
6681       nlist->label = decl;
6682       label_context_stack_vm->labels_used = nlist;
6683     }
6684
6685   TREE_USED (decl) = 1;
6686   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6687 }
6688
6689 /* Generate a computed goto statement to EXPR.  */
6690
6691 tree
6692 c_finish_goto_ptr (tree expr)
6693 {
6694   if (pedantic)
6695     pedwarn ("ISO C forbids %<goto *expr;%>");
6696   expr = convert (ptr_type_node, expr);
6697   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6698 }
6699
6700 /* Generate a C `return' statement.  RETVAL is the expression for what
6701    to return, or a null pointer for `return;' with no value.  */
6702
6703 tree
6704 c_finish_return (tree retval)
6705 {
6706   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6707
6708   if (TREE_THIS_VOLATILE (current_function_decl))
6709     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6710
6711   if (!retval)
6712     {
6713       current_function_returns_null = 1;
6714       if ((warn_return_type || flag_isoc99)
6715           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6716         pedwarn_c99 ("%<return%> with no value, in "
6717                      "function returning non-void");
6718     }
6719   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6720     {
6721       current_function_returns_null = 1;
6722       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6723         pedwarn ("%<return%> with a value, in function returning void");
6724     }
6725   else
6726     {
6727       tree t = convert_for_assignment (valtype, retval, ic_return,
6728                                        NULL_TREE, NULL_TREE, 0);
6729       tree res = DECL_RESULT (current_function_decl);
6730       tree inner;
6731
6732       current_function_returns_value = 1;
6733       if (t == error_mark_node)
6734         return NULL_TREE;
6735
6736       inner = t = convert (TREE_TYPE (res), t);
6737
6738       /* Strip any conversions, additions, and subtractions, and see if
6739          we are returning the address of a local variable.  Warn if so.  */
6740       while (1)
6741         {
6742           switch (TREE_CODE (inner))
6743             {
6744             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6745             case PLUS_EXPR:
6746               inner = TREE_OPERAND (inner, 0);
6747               continue;
6748
6749             case MINUS_EXPR:
6750               /* If the second operand of the MINUS_EXPR has a pointer
6751                  type (or is converted from it), this may be valid, so
6752                  don't give a warning.  */
6753               {
6754                 tree op1 = TREE_OPERAND (inner, 1);
6755
6756                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6757                        && (TREE_CODE (op1) == NOP_EXPR
6758                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6759                            || TREE_CODE (op1) == CONVERT_EXPR))
6760                   op1 = TREE_OPERAND (op1, 0);
6761
6762                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6763                   break;
6764
6765                 inner = TREE_OPERAND (inner, 0);
6766                 continue;
6767               }
6768
6769             case ADDR_EXPR:
6770               inner = TREE_OPERAND (inner, 0);
6771
6772               while (REFERENCE_CLASS_P (inner)
6773                      && TREE_CODE (inner) != INDIRECT_REF)
6774                 inner = TREE_OPERAND (inner, 0);
6775
6776               if (DECL_P (inner)
6777                   && !DECL_EXTERNAL (inner)
6778                   && !TREE_STATIC (inner)
6779                   && DECL_CONTEXT (inner) == current_function_decl)
6780                 warning (0, "function returns address of local variable");
6781               break;
6782
6783             default:
6784               break;
6785             }
6786
6787           break;
6788         }
6789
6790       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6791     }
6792
6793   return add_stmt (build_stmt (RETURN_EXPR, retval));
6794 }
6795 \f
6796 struct c_switch {
6797   /* The SWITCH_EXPR being built.  */
6798   tree switch_expr;
6799
6800   /* The original type of the testing expression, i.e. before the
6801      default conversion is applied.  */
6802   tree orig_type;
6803
6804   /* A splay-tree mapping the low element of a case range to the high
6805      element, or NULL_TREE if there is no high element.  Used to
6806      determine whether or not a new case label duplicates an old case
6807      label.  We need a tree, rather than simply a hash table, because
6808      of the GNU case range extension.  */
6809   splay_tree cases;
6810
6811   /* Number of nested statement expressions within this switch
6812      statement; if nonzero, case and default labels may not
6813      appear.  */
6814   unsigned int blocked_stmt_expr;
6815
6816   /* Scope of outermost declarations of identifiers with variably
6817      modified type within this switch statement; if nonzero, case and
6818      default labels may not appear.  */
6819   unsigned int blocked_vm;
6820
6821   /* The next node on the stack.  */
6822   struct c_switch *next;
6823 };
6824
6825 /* A stack of the currently active switch statements.  The innermost
6826    switch statement is on the top of the stack.  There is no need to
6827    mark the stack for garbage collection because it is only active
6828    during the processing of the body of a function, and we never
6829    collect at that point.  */
6830
6831 struct c_switch *c_switch_stack;
6832
6833 /* Start a C switch statement, testing expression EXP.  Return the new
6834    SWITCH_EXPR.  */
6835
6836 tree
6837 c_start_case (tree exp)
6838 {
6839   enum tree_code code;
6840   tree type, orig_type = error_mark_node;
6841   struct c_switch *cs;
6842
6843   if (exp != error_mark_node)
6844     {
6845       code = TREE_CODE (TREE_TYPE (exp));
6846       orig_type = TREE_TYPE (exp);
6847
6848       if (!INTEGRAL_TYPE_P (orig_type)
6849           && code != ERROR_MARK)
6850         {
6851           error ("switch quantity not an integer");
6852           exp = integer_zero_node;
6853           orig_type = error_mark_node;
6854         }
6855       else
6856         {
6857           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6858
6859           if (!in_system_header
6860               && (type == long_integer_type_node
6861                   || type == long_unsigned_type_node))
6862             warning (OPT_Wtraditional, "%<long%> switch expression not "
6863                      "converted to %<int%> in ISO C");
6864
6865           exp = default_conversion (exp);
6866           type = TREE_TYPE (exp);
6867         }
6868     }
6869
6870   /* Add this new SWITCH_EXPR to the stack.  */
6871   cs = XNEW (struct c_switch);
6872   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6873   cs->orig_type = orig_type;
6874   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6875   cs->blocked_stmt_expr = 0;
6876   cs->blocked_vm = 0;
6877   cs->next = c_switch_stack;
6878   c_switch_stack = cs;
6879
6880   return add_stmt (cs->switch_expr);
6881 }
6882
6883 /* Process a case label.  */
6884
6885 tree
6886 do_case (tree low_value, tree high_value)
6887 {
6888   tree label = NULL_TREE;
6889
6890   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
6891       && !c_switch_stack->blocked_vm)
6892     {
6893       label = c_add_case_label (c_switch_stack->cases,
6894                                 SWITCH_COND (c_switch_stack->switch_expr),
6895                                 c_switch_stack->orig_type,
6896                                 low_value, high_value);
6897       if (label == error_mark_node)
6898         label = NULL_TREE;
6899     }
6900   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
6901     {
6902       if (low_value)
6903         error ("case label in statement expression not containing "
6904                "enclosing switch statement");
6905       else
6906         error ("%<default%> label in statement expression not containing "
6907                "enclosing switch statement");
6908     }
6909   else if (c_switch_stack && c_switch_stack->blocked_vm)
6910     {
6911       if (low_value)
6912         error ("case label in scope of identifier with variably modified "
6913                "type not containing enclosing switch statement");
6914       else
6915         error ("%<default%> label in scope of identifier with variably "
6916                "modified type not containing enclosing switch statement");
6917     }
6918   else if (low_value)
6919     error ("case label not within a switch statement");
6920   else
6921     error ("%<default%> label not within a switch statement");
6922
6923   return label;
6924 }
6925
6926 /* Finish the switch statement.  */
6927
6928 void
6929 c_finish_case (tree body)
6930 {
6931   struct c_switch *cs = c_switch_stack;
6932   location_t switch_location;
6933
6934   SWITCH_BODY (cs->switch_expr) = body;
6935
6936   /* We must not be within a statement expression nested in the switch
6937      at this point; we might, however, be within the scope of an
6938      identifier with variably modified type nested in the switch.  */
6939   gcc_assert (!cs->blocked_stmt_expr);
6940
6941   /* Emit warnings as needed.  */
6942   if (EXPR_HAS_LOCATION (cs->switch_expr))
6943     switch_location = EXPR_LOCATION (cs->switch_expr);
6944   else
6945     switch_location = input_location;
6946   c_do_switch_warnings (cs->cases, switch_location,
6947                         TREE_TYPE (cs->switch_expr),
6948                         SWITCH_COND (cs->switch_expr));
6949
6950   /* Pop the stack.  */
6951   c_switch_stack = cs->next;
6952   splay_tree_delete (cs->cases);
6953   XDELETE (cs);
6954 }
6955 \f
6956 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6957    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6958    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6959    statement, and was not surrounded with parenthesis.  */
6960
6961 void
6962 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6963                   tree else_block, bool nested_if)
6964 {
6965   tree stmt;
6966
6967   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6968   if (warn_parentheses && nested_if && else_block == NULL)
6969     {
6970       tree inner_if = then_block;
6971
6972       /* We know from the grammar productions that there is an IF nested
6973          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6974          it might not be exactly THEN_BLOCK, but should be the last
6975          non-container statement within.  */
6976       while (1)
6977         switch (TREE_CODE (inner_if))
6978           {
6979           case COND_EXPR:
6980             goto found;
6981           case BIND_EXPR:
6982             inner_if = BIND_EXPR_BODY (inner_if);
6983             break;
6984           case STATEMENT_LIST:
6985             inner_if = expr_last (then_block);
6986             break;
6987           case TRY_FINALLY_EXPR:
6988           case TRY_CATCH_EXPR:
6989             inner_if = TREE_OPERAND (inner_if, 0);
6990             break;
6991           default:
6992             gcc_unreachable ();
6993           }
6994     found:
6995
6996       if (COND_EXPR_ELSE (inner_if))
6997          warning (OPT_Wparentheses,
6998                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
6999                   &if_locus);
7000     }
7001
7002   /* Diagnose ";" via the special empty statement node that we create.  */
7003   if (extra_warnings)
7004     {
7005       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
7006         {
7007           if (!else_block)
7008             warning (0, "%Hempty body in an if-statement",
7009                      EXPR_LOCUS (then_block));
7010           then_block = alloc_stmt_list ();
7011         }
7012       if (else_block
7013           && TREE_CODE (else_block) == NOP_EXPR
7014           && !TREE_TYPE (else_block))
7015         {
7016           warning (0, "%Hempty body in an else-statement",
7017                    EXPR_LOCUS (else_block));
7018           else_block = alloc_stmt_list ();
7019         }
7020     }
7021
7022   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7023   SET_EXPR_LOCATION (stmt, if_locus);
7024   add_stmt (stmt);
7025 }
7026
7027 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7028    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7029    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7030    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7031    the continue label.  Everything is allowed to be NULL.  */
7032
7033 void
7034 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7035                tree blab, tree clab, bool cond_is_first)
7036 {
7037   tree entry = NULL, exit = NULL, t;
7038
7039   /* If the condition is zero don't generate a loop construct.  */
7040   if (cond && integer_zerop (cond))
7041     {
7042       if (cond_is_first)
7043         {
7044           t = build_and_jump (&blab);
7045           SET_EXPR_LOCATION (t, start_locus);
7046           add_stmt (t);
7047         }
7048     }
7049   else
7050     {
7051       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7052
7053       /* If we have an exit condition, then we build an IF with gotos either
7054          out of the loop, or to the top of it.  If there's no exit condition,
7055          then we just build a jump back to the top.  */
7056       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7057
7058       if (cond && !integer_nonzerop (cond))
7059         {
7060           /* Canonicalize the loop condition to the end.  This means
7061              generating a branch to the loop condition.  Reuse the
7062              continue label, if possible.  */
7063           if (cond_is_first)
7064             {
7065               if (incr || !clab)
7066                 {
7067                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7068                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7069                 }
7070               else
7071                 t = build1 (GOTO_EXPR, void_type_node, clab);
7072               SET_EXPR_LOCATION (t, start_locus);
7073               add_stmt (t);
7074             }
7075
7076           t = build_and_jump (&blab);
7077           exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
7078           exit = fold (exit);
7079           if (cond_is_first)
7080             SET_EXPR_LOCATION (exit, start_locus);
7081           else
7082             SET_EXPR_LOCATION (exit, input_location);
7083         }
7084
7085       add_stmt (top);
7086     }
7087
7088   if (body)
7089     add_stmt (body);
7090   if (clab)
7091     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7092   if (incr)
7093     add_stmt (incr);
7094   if (entry)
7095     add_stmt (entry);
7096   if (exit)
7097     add_stmt (exit);
7098   if (blab)
7099     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7100 }
7101
7102 tree
7103 c_finish_bc_stmt (tree *label_p, bool is_break)
7104 {
7105   bool skip;
7106   tree label = *label_p;
7107
7108   /* In switch statements break is sometimes stylistically used after
7109      a return statement.  This can lead to spurious warnings about
7110      control reaching the end of a non-void function when it is
7111      inlined.  Note that we are calling block_may_fallthru with
7112      language specific tree nodes; this works because
7113      block_may_fallthru returns true when given something it does not
7114      understand.  */
7115   skip = !block_may_fallthru (cur_stmt_list);
7116
7117   if (!label)
7118     {
7119       if (!skip)
7120         *label_p = label = create_artificial_label ();
7121     }
7122   else if (TREE_CODE (label) != LABEL_DECL)
7123     {
7124       if (is_break)
7125         error ("break statement not within loop or switch");
7126       else
7127         error ("continue statement not within a loop");
7128       return NULL_TREE;
7129     }
7130
7131   if (skip)
7132     return NULL_TREE;
7133
7134   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7135 }
7136
7137 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7138
7139 static void
7140 emit_side_effect_warnings (tree expr)
7141 {
7142   if (expr == error_mark_node)
7143     ;
7144   else if (!TREE_SIDE_EFFECTS (expr))
7145     {
7146       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7147         warning (0, "%Hstatement with no effect",
7148                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7149     }
7150   else if (warn_unused_value)
7151     warn_if_unused_value (expr, input_location);
7152 }
7153
7154 /* Process an expression as if it were a complete statement.  Emit
7155    diagnostics, but do not call ADD_STMT.  */
7156
7157 tree
7158 c_process_expr_stmt (tree expr)
7159 {
7160   if (!expr)
7161     return NULL_TREE;
7162
7163   if (warn_sequence_point)
7164     verify_sequence_points (expr);
7165
7166   if (TREE_TYPE (expr) != error_mark_node
7167       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7168       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7169     error ("expression statement has incomplete type");
7170
7171   /* If we're not processing a statement expression, warn about unused values.
7172      Warnings for statement expressions will be emitted later, once we figure
7173      out which is the result.  */
7174   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7175       && (extra_warnings || warn_unused_value))
7176     emit_side_effect_warnings (expr);
7177
7178   /* If the expression is not of a type to which we cannot assign a line
7179      number, wrap the thing in a no-op NOP_EXPR.  */
7180   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7181     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7182
7183   if (EXPR_P (expr))
7184     SET_EXPR_LOCATION (expr, input_location);
7185
7186   return expr;
7187 }
7188
7189 /* Emit an expression as a statement.  */
7190
7191 tree
7192 c_finish_expr_stmt (tree expr)
7193 {
7194   if (expr)
7195     return add_stmt (c_process_expr_stmt (expr));
7196   else
7197     return NULL;
7198 }
7199
7200 /* Do the opposite and emit a statement as an expression.  To begin,
7201    create a new binding level and return it.  */
7202
7203 tree
7204 c_begin_stmt_expr (void)
7205 {
7206   tree ret;
7207   struct c_label_context_se *nstack;
7208   struct c_label_list *glist;
7209
7210   /* We must force a BLOCK for this level so that, if it is not expanded
7211      later, there is a way to turn off the entire subtree of blocks that
7212      are contained in it.  */
7213   keep_next_level ();
7214   ret = c_begin_compound_stmt (true);
7215   if (c_switch_stack)
7216     {
7217       c_switch_stack->blocked_stmt_expr++;
7218       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7219     }
7220   for (glist = label_context_stack_se->labels_used;
7221        glist != NULL;
7222        glist = glist->next)
7223     {
7224       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7225     }
7226   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7227   nstack->labels_def = NULL;
7228   nstack->labels_used = NULL;
7229   nstack->next = label_context_stack_se;
7230   label_context_stack_se = nstack;
7231
7232   /* Mark the current statement list as belonging to a statement list.  */
7233   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7234
7235   return ret;
7236 }
7237
7238 tree
7239 c_finish_stmt_expr (tree body)
7240 {
7241   tree last, type, tmp, val;
7242   tree *last_p;
7243   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7244
7245   body = c_end_compound_stmt (body, true);
7246   if (c_switch_stack)
7247     {
7248       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7249       c_switch_stack->blocked_stmt_expr--;
7250     }
7251   /* It is no longer possible to jump to labels defined within this
7252      statement expression.  */
7253   for (dlist = label_context_stack_se->labels_def;
7254        dlist != NULL;
7255        dlist = dlist->next)
7256     {
7257       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7258     }
7259   /* It is again possible to define labels with a goto just outside
7260      this statement expression.  */
7261   for (glist = label_context_stack_se->next->labels_used;
7262        glist != NULL;
7263        glist = glist->next)
7264     {
7265       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7266       glist_prev = glist;
7267     }
7268   if (glist_prev != NULL)
7269     glist_prev->next = label_context_stack_se->labels_used;
7270   else
7271     label_context_stack_se->next->labels_used
7272       = label_context_stack_se->labels_used;
7273   label_context_stack_se = label_context_stack_se->next;
7274
7275   /* Locate the last statement in BODY.  See c_end_compound_stmt
7276      about always returning a BIND_EXPR.  */
7277   last_p = &BIND_EXPR_BODY (body);
7278   last = BIND_EXPR_BODY (body);
7279
7280  continue_searching:
7281   if (TREE_CODE (last) == STATEMENT_LIST)
7282     {
7283       tree_stmt_iterator i;
7284
7285       /* This can happen with degenerate cases like ({ }).  No value.  */
7286       if (!TREE_SIDE_EFFECTS (last))
7287         return body;
7288
7289       /* If we're supposed to generate side effects warnings, process
7290          all of the statements except the last.  */
7291       if (extra_warnings || warn_unused_value)
7292         {
7293           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7294             emit_side_effect_warnings (tsi_stmt (i));
7295         }
7296       else
7297         i = tsi_last (last);
7298       last_p = tsi_stmt_ptr (i);
7299       last = *last_p;
7300     }
7301
7302   /* If the end of the list is exception related, then the list was split
7303      by a call to push_cleanup.  Continue searching.  */
7304   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7305       || TREE_CODE (last) == TRY_CATCH_EXPR)
7306     {
7307       last_p = &TREE_OPERAND (last, 0);
7308       last = *last_p;
7309       goto continue_searching;
7310     }
7311
7312   /* In the case that the BIND_EXPR is not necessary, return the
7313      expression out from inside it.  */
7314   if (last == error_mark_node
7315       || (last == BIND_EXPR_BODY (body)
7316           && BIND_EXPR_VARS (body) == NULL))
7317     return last;
7318
7319   /* Extract the type of said expression.  */
7320   type = TREE_TYPE (last);
7321
7322   /* If we're not returning a value at all, then the BIND_EXPR that
7323      we already have is a fine expression to return.  */
7324   if (!type || VOID_TYPE_P (type))
7325     return body;
7326
7327   /* Now that we've located the expression containing the value, it seems
7328      silly to make voidify_wrapper_expr repeat the process.  Create a
7329      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7330   tmp = create_tmp_var_raw (type, NULL);
7331
7332   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7333      tree_expr_nonnegative_p giving up immediately.  */
7334   val = last;
7335   if (TREE_CODE (val) == NOP_EXPR
7336       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7337     val = TREE_OPERAND (val, 0);
7338
7339   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7340   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7341
7342   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7343 }
7344
7345 /* Begin the scope of an identifier of variably modified type, scope
7346    number SCOPE.  Jumping from outside this scope to inside it is not
7347    permitted.  */
7348
7349 void
7350 c_begin_vm_scope (unsigned int scope)
7351 {
7352   struct c_label_context_vm *nstack;
7353   struct c_label_list *glist;
7354
7355   gcc_assert (scope > 0);
7356   if (c_switch_stack && !c_switch_stack->blocked_vm)
7357     c_switch_stack->blocked_vm = scope;
7358   for (glist = label_context_stack_vm->labels_used;
7359        glist != NULL;
7360        glist = glist->next)
7361     {
7362       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7363     }
7364   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7365   nstack->labels_def = NULL;
7366   nstack->labels_used = NULL;
7367   nstack->scope = scope;
7368   nstack->next = label_context_stack_vm;
7369   label_context_stack_vm = nstack;
7370 }
7371
7372 /* End a scope which may contain identifiers of variably modified
7373    type, scope number SCOPE.  */
7374
7375 void
7376 c_end_vm_scope (unsigned int scope)
7377 {
7378   if (label_context_stack_vm == NULL)
7379     return;
7380   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7381     c_switch_stack->blocked_vm = 0;
7382   /* We may have a number of nested scopes of identifiers with
7383      variably modified type, all at this depth.  Pop each in turn.  */
7384   while (label_context_stack_vm->scope == scope)
7385     {
7386       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7387
7388       /* It is no longer possible to jump to labels defined within this
7389          scope.  */
7390       for (dlist = label_context_stack_vm->labels_def;
7391            dlist != NULL;
7392            dlist = dlist->next)
7393         {
7394           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7395         }
7396       /* It is again possible to define labels with a goto just outside
7397          this scope.  */
7398       for (glist = label_context_stack_vm->next->labels_used;
7399            glist != NULL;
7400            glist = glist->next)
7401         {
7402           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7403           glist_prev = glist;
7404         }
7405       if (glist_prev != NULL)
7406         glist_prev->next = label_context_stack_vm->labels_used;
7407       else
7408         label_context_stack_vm->next->labels_used
7409           = label_context_stack_vm->labels_used;
7410       label_context_stack_vm = label_context_stack_vm->next;
7411     }
7412 }
7413 \f
7414 /* Begin and end compound statements.  This is as simple as pushing
7415    and popping new statement lists from the tree.  */
7416
7417 tree
7418 c_begin_compound_stmt (bool do_scope)
7419 {
7420   tree stmt = push_stmt_list ();
7421   if (do_scope)
7422     push_scope ();
7423   return stmt;
7424 }
7425
7426 tree
7427 c_end_compound_stmt (tree stmt, bool do_scope)
7428 {
7429   tree block = NULL;
7430
7431   if (do_scope)
7432     {
7433       if (c_dialect_objc ())
7434         objc_clear_super_receiver ();
7435       block = pop_scope ();
7436     }
7437
7438   stmt = pop_stmt_list (stmt);
7439   stmt = c_build_bind_expr (block, stmt);
7440
7441   /* If this compound statement is nested immediately inside a statement
7442      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7443      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7444      STATEMENT_LISTs merge, and thus we can lose track of what statement
7445      was really last.  */
7446   if (cur_stmt_list
7447       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7448       && TREE_CODE (stmt) != BIND_EXPR)
7449     {
7450       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7451       TREE_SIDE_EFFECTS (stmt) = 1;
7452     }
7453
7454   return stmt;
7455 }
7456
7457 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7458    when the current scope is exited.  EH_ONLY is true when this is not
7459    meant to apply to normal control flow transfer.  */
7460
7461 void
7462 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7463 {
7464   enum tree_code code;
7465   tree stmt, list;
7466   bool stmt_expr;
7467
7468   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7469   stmt = build_stmt (code, NULL, cleanup);
7470   add_stmt (stmt);
7471   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7472   list = push_stmt_list ();
7473   TREE_OPERAND (stmt, 0) = list;
7474   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7475 }
7476 \f
7477 /* Build a binary-operation expression without default conversions.
7478    CODE is the kind of expression to build.
7479    This function differs from `build' in several ways:
7480    the data type of the result is computed and recorded in it,
7481    warnings are generated if arg data types are invalid,
7482    special handling for addition and subtraction of pointers is known,
7483    and some optimization is done (operations on narrow ints
7484    are done in the narrower type when that gives the same result).
7485    Constant folding is also done before the result is returned.
7486
7487    Note that the operands will never have enumeral types, or function
7488    or array types, because either they will have the default conversions
7489    performed or they have both just been converted to some other type in which
7490    the arithmetic is to be done.  */
7491
7492 tree
7493 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7494                  int convert_p)
7495 {
7496   tree type0, type1;
7497   enum tree_code code0, code1;
7498   tree op0, op1;
7499   const char *invalid_op_diag;
7500
7501   /* Expression code to give to the expression when it is built.
7502      Normally this is CODE, which is what the caller asked for,
7503      but in some special cases we change it.  */
7504   enum tree_code resultcode = code;
7505
7506   /* Data type in which the computation is to be performed.
7507      In the simplest cases this is the common type of the arguments.  */
7508   tree result_type = NULL;
7509
7510   /* Nonzero means operands have already been type-converted
7511      in whatever way is necessary.
7512      Zero means they need to be converted to RESULT_TYPE.  */
7513   int converted = 0;
7514
7515   /* Nonzero means create the expression with this type, rather than
7516      RESULT_TYPE.  */
7517   tree build_type = 0;
7518
7519   /* Nonzero means after finally constructing the expression
7520      convert it to this type.  */
7521   tree final_type = 0;
7522
7523   /* Nonzero if this is an operation like MIN or MAX which can
7524      safely be computed in short if both args are promoted shorts.
7525      Also implies COMMON.
7526      -1 indicates a bitwise operation; this makes a difference
7527      in the exact conditions for when it is safe to do the operation
7528      in a narrower mode.  */
7529   int shorten = 0;
7530
7531   /* Nonzero if this is a comparison operation;
7532      if both args are promoted shorts, compare the original shorts.
7533      Also implies COMMON.  */
7534   int short_compare = 0;
7535
7536   /* Nonzero if this is a right-shift operation, which can be computed on the
7537      original short and then promoted if the operand is a promoted short.  */
7538   int short_shift = 0;
7539
7540   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7541   int common = 0;
7542
7543   /* True means types are compatible as far as ObjC is concerned.  */
7544   bool objc_ok;
7545
7546   if (convert_p)
7547     {
7548       op0 = default_conversion (orig_op0);
7549       op1 = default_conversion (orig_op1);
7550     }
7551   else
7552     {
7553       op0 = orig_op0;
7554       op1 = orig_op1;
7555     }
7556
7557   type0 = TREE_TYPE (op0);
7558   type1 = TREE_TYPE (op1);
7559
7560   /* The expression codes of the data types of the arguments tell us
7561      whether the arguments are integers, floating, pointers, etc.  */
7562   code0 = TREE_CODE (type0);
7563   code1 = TREE_CODE (type1);
7564
7565   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7566   STRIP_TYPE_NOPS (op0);
7567   STRIP_TYPE_NOPS (op1);
7568
7569   /* If an error was already reported for one of the arguments,
7570      avoid reporting another error.  */
7571
7572   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7573     return error_mark_node;
7574
7575   if ((invalid_op_diag
7576        = targetm.invalid_binary_op (code, type0, type1)))
7577     {
7578       error (invalid_op_diag);
7579       return error_mark_node;
7580     }
7581
7582   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7583
7584   switch (code)
7585     {
7586     case PLUS_EXPR:
7587       /* Handle the pointer + int case.  */
7588       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7589         return pointer_int_sum (PLUS_EXPR, op0, op1);
7590       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7591         return pointer_int_sum (PLUS_EXPR, op1, op0);
7592       else
7593         common = 1;
7594       break;
7595
7596     case MINUS_EXPR:
7597       /* Subtraction of two similar pointers.
7598          We must subtract them as integers, then divide by object size.  */
7599       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7600           && comp_target_types (type0, type1))
7601         return pointer_diff (op0, op1);
7602       /* Handle pointer minus int.  Just like pointer plus int.  */
7603       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7604         return pointer_int_sum (MINUS_EXPR, op0, op1);
7605       else
7606         common = 1;
7607       break;
7608
7609     case MULT_EXPR:
7610       common = 1;
7611       break;
7612
7613     case TRUNC_DIV_EXPR:
7614     case CEIL_DIV_EXPR:
7615     case FLOOR_DIV_EXPR:
7616     case ROUND_DIV_EXPR:
7617     case EXACT_DIV_EXPR:
7618       /* Floating point division by zero is a legitimate way to obtain
7619          infinities and NaNs.  */
7620       if (skip_evaluation == 0 && integer_zerop (op1))
7621         warning (OPT_Wdiv_by_zero, "division by zero");
7622
7623       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7624            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7625           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7626               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7627         {
7628           enum tree_code tcode0 = code0, tcode1 = code1;
7629
7630           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7631             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7632           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7633             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7634
7635           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7636             resultcode = RDIV_EXPR;
7637           else
7638             /* Although it would be tempting to shorten always here, that
7639                loses on some targets, since the modulo instruction is
7640                undefined if the quotient can't be represented in the
7641                computation mode.  We shorten only if unsigned or if
7642                dividing by something we know != -1.  */
7643             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7644                        || (TREE_CODE (op1) == INTEGER_CST
7645                            && !integer_all_onesp (op1)));
7646           common = 1;
7647         }
7648       break;
7649
7650     case BIT_AND_EXPR:
7651     case BIT_IOR_EXPR:
7652     case BIT_XOR_EXPR:
7653       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7654         shorten = -1;
7655       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7656         common = 1;
7657       break;
7658
7659     case TRUNC_MOD_EXPR:
7660     case FLOOR_MOD_EXPR:
7661       if (skip_evaluation == 0 && integer_zerop (op1))
7662         warning (OPT_Wdiv_by_zero, "division by zero");
7663
7664       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7665         {
7666           /* Although it would be tempting to shorten always here, that loses
7667              on some targets, since the modulo instruction is undefined if the
7668              quotient can't be represented in the computation mode.  We shorten
7669              only if unsigned or if dividing by something we know != -1.  */
7670           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7671                      || (TREE_CODE (op1) == INTEGER_CST
7672                          && !integer_all_onesp (op1)));
7673           common = 1;
7674         }
7675       break;
7676
7677     case TRUTH_ANDIF_EXPR:
7678     case TRUTH_ORIF_EXPR:
7679     case TRUTH_AND_EXPR:
7680     case TRUTH_OR_EXPR:
7681     case TRUTH_XOR_EXPR:
7682       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7683            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7684           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7685               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7686         {
7687           /* Result of these operations is always an int,
7688              but that does not mean the operands should be
7689              converted to ints!  */
7690           result_type = integer_type_node;
7691           op0 = c_common_truthvalue_conversion (op0);
7692           op1 = c_common_truthvalue_conversion (op1);
7693           converted = 1;
7694         }
7695       break;
7696
7697       /* Shift operations: result has same type as first operand;
7698          always convert second operand to int.
7699          Also set SHORT_SHIFT if shifting rightward.  */
7700
7701     case RSHIFT_EXPR:
7702       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7703         {
7704           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7705             {
7706               if (tree_int_cst_sgn (op1) < 0)
7707                 warning (0, "right shift count is negative");
7708               else
7709                 {
7710                   if (!integer_zerop (op1))
7711                     short_shift = 1;
7712
7713                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7714                     warning (0, "right shift count >= width of type");
7715                 }
7716             }
7717
7718           /* Use the type of the value to be shifted.  */
7719           result_type = type0;
7720           /* Convert the shift-count to an integer, regardless of size
7721              of value being shifted.  */
7722           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7723             op1 = convert (integer_type_node, op1);
7724           /* Avoid converting op1 to result_type later.  */
7725           converted = 1;
7726         }
7727       break;
7728
7729     case LSHIFT_EXPR:
7730       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7731         {
7732           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7733             {
7734               if (tree_int_cst_sgn (op1) < 0)
7735                 warning (0, "left shift count is negative");
7736
7737               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7738                 warning (0, "left shift count >= width of type");
7739             }
7740
7741           /* Use the type of the value to be shifted.  */
7742           result_type = type0;
7743           /* Convert the shift-count to an integer, regardless of size
7744              of value being shifted.  */
7745           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7746             op1 = convert (integer_type_node, op1);
7747           /* Avoid converting op1 to result_type later.  */
7748           converted = 1;
7749         }
7750       break;
7751
7752     case EQ_EXPR:
7753     case NE_EXPR:
7754       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7755         warning (OPT_Wfloat_equal,
7756                  "comparing floating point with == or != is unsafe");
7757       /* Result of comparison is always int,
7758          but don't convert the args to int!  */
7759       build_type = integer_type_node;
7760       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7761            || code0 == COMPLEX_TYPE)
7762           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7763               || code1 == COMPLEX_TYPE))
7764         short_compare = 1;
7765       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7766         {
7767           tree tt0 = TREE_TYPE (type0);
7768           tree tt1 = TREE_TYPE (type1);
7769           /* Anything compares with void *.  void * compares with anything.
7770              Otherwise, the targets must be compatible
7771              and both must be object or both incomplete.  */
7772           if (comp_target_types (type0, type1))
7773             result_type = common_pointer_type (type0, type1);
7774           else if (VOID_TYPE_P (tt0))
7775             {
7776               /* op0 != orig_op0 detects the case of something
7777                  whose value is 0 but which isn't a valid null ptr const.  */
7778               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7779                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7780                 pedwarn ("ISO C forbids comparison of %<void *%>"
7781                          " with function pointer");
7782             }
7783           else if (VOID_TYPE_P (tt1))
7784             {
7785               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7786                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7787                 pedwarn ("ISO C forbids comparison of %<void *%>"
7788                          " with function pointer");
7789             }
7790           else
7791             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7792             if (!objc_ok)
7793               pedwarn ("comparison of distinct pointer types lacks a cast");
7794
7795           if (result_type == NULL_TREE)
7796             result_type = ptr_type_node;
7797         }
7798       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7799                && integer_zerop (op1))
7800         result_type = type0;
7801       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7802                && integer_zerop (op0))
7803         result_type = type1;
7804       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7805         {
7806           result_type = type0;
7807           pedwarn ("comparison between pointer and integer");
7808         }
7809       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7810         {
7811           result_type = type1;
7812           pedwarn ("comparison between pointer and integer");
7813         }
7814       break;
7815
7816     case LE_EXPR:
7817     case GE_EXPR:
7818     case LT_EXPR:
7819     case GT_EXPR:
7820       build_type = integer_type_node;
7821       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7822           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7823         short_compare = 1;
7824       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7825         {
7826           if (comp_target_types (type0, type1))
7827             {
7828               result_type = common_pointer_type (type0, type1);
7829               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7830                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7831                 pedwarn ("comparison of complete and incomplete pointers");
7832               else if (pedantic
7833                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7834                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7835             }
7836           else
7837             {
7838               result_type = ptr_type_node;
7839               pedwarn ("comparison of distinct pointer types lacks a cast");
7840             }
7841         }
7842       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7843                && integer_zerop (op1))
7844         {
7845           result_type = type0;
7846           if (pedantic || extra_warnings)
7847             pedwarn ("ordered comparison of pointer with integer zero");
7848         }
7849       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7850                && integer_zerop (op0))
7851         {
7852           result_type = type1;
7853           if (pedantic)
7854             pedwarn ("ordered comparison of pointer with integer zero");
7855         }
7856       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7857         {
7858           result_type = type0;
7859           pedwarn ("comparison between pointer and integer");
7860         }
7861       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7862         {
7863           result_type = type1;
7864           pedwarn ("comparison between pointer and integer");
7865         }
7866       break;
7867
7868     default:
7869       gcc_unreachable ();
7870     }
7871
7872   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7873     return error_mark_node;
7874
7875   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
7876       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
7877           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
7878                                                     TREE_TYPE (type1))))
7879     {
7880       binary_op_error (code);
7881       return error_mark_node;
7882     }
7883
7884   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7885        || code0 == VECTOR_TYPE)
7886       &&
7887       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7888        || code1 == VECTOR_TYPE))
7889     {
7890       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7891
7892       if (shorten || common || short_compare)
7893         result_type = c_common_type (type0, type1);
7894
7895       /* For certain operations (which identify themselves by shorten != 0)
7896          if both args were extended from the same smaller type,
7897          do the arithmetic in that type and then extend.
7898
7899          shorten !=0 and !=1 indicates a bitwise operation.
7900          For them, this optimization is safe only if
7901          both args are zero-extended or both are sign-extended.
7902          Otherwise, we might change the result.
7903          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7904          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7905
7906       if (shorten && none_complex)
7907         {
7908           int unsigned0, unsigned1;
7909           tree arg0 = get_narrower (op0, &unsigned0);
7910           tree arg1 = get_narrower (op1, &unsigned1);
7911           /* UNS is 1 if the operation to be done is an unsigned one.  */
7912           int uns = TYPE_UNSIGNED (result_type);
7913           tree type;
7914
7915           final_type = result_type;
7916
7917           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7918              but it *requires* conversion to FINAL_TYPE.  */
7919
7920           if ((TYPE_PRECISION (TREE_TYPE (op0))
7921                == TYPE_PRECISION (TREE_TYPE (arg0)))
7922               && TREE_TYPE (op0) != final_type)
7923             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7924           if ((TYPE_PRECISION (TREE_TYPE (op1))
7925                == TYPE_PRECISION (TREE_TYPE (arg1)))
7926               && TREE_TYPE (op1) != final_type)
7927             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7928
7929           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7930
7931           /* For bitwise operations, signedness of nominal type
7932              does not matter.  Consider only how operands were extended.  */
7933           if (shorten == -1)
7934             uns = unsigned0;
7935
7936           /* Note that in all three cases below we refrain from optimizing
7937              an unsigned operation on sign-extended args.
7938              That would not be valid.  */
7939
7940           /* Both args variable: if both extended in same way
7941              from same width, do it in that width.
7942              Do it unsigned if args were zero-extended.  */
7943           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7944                < TYPE_PRECISION (result_type))
7945               && (TYPE_PRECISION (TREE_TYPE (arg1))
7946                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7947               && unsigned0 == unsigned1
7948               && (unsigned0 || !uns))
7949             result_type
7950               = c_common_signed_or_unsigned_type
7951               (unsigned0, c_common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7952           else if (TREE_CODE (arg0) == INTEGER_CST
7953                    && (unsigned1 || !uns)
7954                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7955                        < TYPE_PRECISION (result_type))
7956                    && (type
7957                        = c_common_signed_or_unsigned_type (unsigned1,
7958                                                            TREE_TYPE (arg1)),
7959                        int_fits_type_p (arg0, type)))
7960             result_type = type;
7961           else if (TREE_CODE (arg1) == INTEGER_CST
7962                    && (unsigned0 || !uns)
7963                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7964                        < TYPE_PRECISION (result_type))
7965                    && (type
7966                        = c_common_signed_or_unsigned_type (unsigned0,
7967                                                            TREE_TYPE (arg0)),
7968                        int_fits_type_p (arg1, type)))
7969             result_type = type;
7970         }
7971
7972       /* Shifts can be shortened if shifting right.  */
7973
7974       if (short_shift)
7975         {
7976           int unsigned_arg;
7977           tree arg0 = get_narrower (op0, &unsigned_arg);
7978
7979           final_type = result_type;
7980
7981           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7982             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7983
7984           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7985               /* We can shorten only if the shift count is less than the
7986                  number of bits in the smaller type size.  */
7987               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7988               /* We cannot drop an unsigned shift after sign-extension.  */
7989               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7990             {
7991               /* Do an unsigned shift if the operand was zero-extended.  */
7992               result_type
7993                 = c_common_signed_or_unsigned_type (unsigned_arg,
7994                                                     TREE_TYPE (arg0));
7995               /* Convert value-to-be-shifted to that type.  */
7996               if (TREE_TYPE (op0) != result_type)
7997                 op0 = convert (result_type, op0);
7998               converted = 1;
7999             }
8000         }
8001
8002       /* Comparison operations are shortened too but differently.
8003          They identify themselves by setting short_compare = 1.  */
8004
8005       if (short_compare)
8006         {
8007           /* Don't write &op0, etc., because that would prevent op0
8008              from being kept in a register.
8009              Instead, make copies of the our local variables and
8010              pass the copies by reference, then copy them back afterward.  */
8011           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8012           enum tree_code xresultcode = resultcode;
8013           tree val
8014             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8015
8016           if (val != 0)
8017             return val;
8018
8019           op0 = xop0, op1 = xop1;
8020           converted = 1;
8021           resultcode = xresultcode;
8022
8023           if (warn_sign_compare && skip_evaluation == 0)
8024             {
8025               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8026               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8027               int unsignedp0, unsignedp1;
8028               tree primop0 = get_narrower (op0, &unsignedp0);
8029               tree primop1 = get_narrower (op1, &unsignedp1);
8030
8031               xop0 = orig_op0;
8032               xop1 = orig_op1;
8033               STRIP_TYPE_NOPS (xop0);
8034               STRIP_TYPE_NOPS (xop1);
8035
8036               /* Give warnings for comparisons between signed and unsigned
8037                  quantities that may fail.
8038
8039                  Do the checking based on the original operand trees, so that
8040                  casts will be considered, but default promotions won't be.
8041
8042                  Do not warn if the comparison is being done in a signed type,
8043                  since the signed type will only be chosen if it can represent
8044                  all the values of the unsigned type.  */
8045               if (!TYPE_UNSIGNED (result_type))
8046                 /* OK */;
8047               /* Do not warn if both operands are the same signedness.  */
8048               else if (op0_signed == op1_signed)
8049                 /* OK */;
8050               else
8051                 {
8052                   tree sop, uop;
8053
8054                   if (op0_signed)
8055                     sop = xop0, uop = xop1;
8056                   else
8057                     sop = xop1, uop = xop0;
8058
8059                   /* Do not warn if the signed quantity is an
8060                      unsuffixed integer literal (or some static
8061                      constant expression involving such literals or a
8062                      conditional expression involving such literals)
8063                      and it is non-negative.  */
8064                   if (tree_expr_nonnegative_p (sop))
8065                     /* OK */;
8066                   /* Do not warn if the comparison is an equality operation,
8067                      the unsigned quantity is an integral constant, and it
8068                      would fit in the result if the result were signed.  */
8069                   else if (TREE_CODE (uop) == INTEGER_CST
8070                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8071                            && int_fits_type_p
8072                            (uop, c_common_signed_type (result_type)))
8073                     /* OK */;
8074                   /* Do not warn if the unsigned quantity is an enumeration
8075                      constant and its maximum value would fit in the result
8076                      if the result were signed.  */
8077                   else if (TREE_CODE (uop) == INTEGER_CST
8078                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8079                            && int_fits_type_p
8080                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8081                             c_common_signed_type (result_type)))
8082                     /* OK */;
8083                   else
8084                     warning (0, "comparison between signed and unsigned");
8085                 }
8086
8087               /* Warn if two unsigned values are being compared in a size
8088                  larger than their original size, and one (and only one) is the
8089                  result of a `~' operator.  This comparison will always fail.
8090
8091                  Also warn if one operand is a constant, and the constant
8092                  does not have all bits set that are set in the ~ operand
8093                  when it is extended.  */
8094
8095               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8096                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8097                 {
8098                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8099                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8100                                             &unsignedp0);
8101                   else
8102                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8103                                             &unsignedp1);
8104
8105                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8106                     {
8107                       tree primop;
8108                       HOST_WIDE_INT constant, mask;
8109                       int unsignedp, bits;
8110
8111                       if (host_integerp (primop0, 0))
8112                         {
8113                           primop = primop1;
8114                           unsignedp = unsignedp1;
8115                           constant = tree_low_cst (primop0, 0);
8116                         }
8117                       else
8118                         {
8119                           primop = primop0;
8120                           unsignedp = unsignedp0;
8121                           constant = tree_low_cst (primop1, 0);
8122                         }
8123
8124                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8125                       if (bits < TYPE_PRECISION (result_type)
8126                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8127                         {
8128                           mask = (~(HOST_WIDE_INT) 0) << bits;
8129                           if ((mask & constant) != mask)
8130                             warning (0, "comparison of promoted ~unsigned with constant");
8131                         }
8132                     }
8133                   else if (unsignedp0 && unsignedp1
8134                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8135                                < TYPE_PRECISION (result_type))
8136                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8137                                < TYPE_PRECISION (result_type)))
8138                     warning (0, "comparison of promoted ~unsigned with unsigned");
8139                 }
8140             }
8141         }
8142     }
8143
8144   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8145      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8146      Then the expression will be built.
8147      It will be given type FINAL_TYPE if that is nonzero;
8148      otherwise, it will be given type RESULT_TYPE.  */
8149
8150   if (!result_type)
8151     {
8152       binary_op_error (code);
8153       return error_mark_node;
8154     }
8155
8156   if (!converted)
8157     {
8158       if (TREE_TYPE (op0) != result_type)
8159         op0 = convert (result_type, op0);
8160       if (TREE_TYPE (op1) != result_type)
8161         op1 = convert (result_type, op1);
8162
8163       /* This can happen if one operand has a vector type, and the other
8164          has a different type.  */
8165       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8166         return error_mark_node;
8167     }
8168
8169   if (build_type == NULL_TREE)
8170     build_type = result_type;
8171
8172   {
8173     tree result = build2 (resultcode, build_type, op0, op1);
8174
8175     /* Treat expressions in initializers specially as they can't trap.  */
8176     result = require_constant_value ? fold_initializer (result)
8177                                     : fold (result);
8178
8179     if (final_type != 0)
8180       result = convert (final_type, result);
8181     return result;
8182   }
8183 }
8184
8185
8186 /* Convert EXPR to be a truth-value, validating its type for this
8187    purpose.  */
8188
8189 tree
8190 c_objc_common_truthvalue_conversion (tree expr)
8191 {
8192   switch (TREE_CODE (TREE_TYPE (expr)))
8193     {
8194     case ARRAY_TYPE:
8195       error ("used array that cannot be converted to pointer where scalar is required");
8196       return error_mark_node;
8197
8198     case RECORD_TYPE:
8199       error ("used struct type value where scalar is required");
8200       return error_mark_node;
8201
8202     case UNION_TYPE:
8203       error ("used union type value where scalar is required");
8204       return error_mark_node;
8205
8206     case FUNCTION_TYPE:
8207       gcc_unreachable ();
8208
8209     default:
8210       break;
8211     }
8212
8213   /* ??? Should we also give an error for void and vectors rather than
8214      leaving those to give errors later?  */
8215   return c_common_truthvalue_conversion (expr);
8216 }
8217 \f
8218
8219 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8220    required.  */
8221
8222 tree
8223 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8224                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8225 {
8226   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8227     {
8228       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8229       /* Executing a compound literal inside a function reinitializes
8230          it.  */
8231       if (!TREE_STATIC (decl))
8232         *se = true;
8233       return decl;
8234     }
8235   else
8236     return expr;
8237 }