gcc/cp/tree.c

   1 /* Language-dependent node constructors for parse phase of GNU compiler.
   2    Copyright (C) 1987-2014 Free Software Foundation, Inc.
   3    Hacked by Michael Tiemann (tiemann@cygnus.com)
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "tree-hasher.h"
  27 #include "stor-layout.h"
  28 #include "print-tree.h"
  29 #include "tree-iterator.h"
  30 #include "cp-tree.h"
  31 #include "flags.h"
  32 #include "tree-inline.h"
  33 #include "debug.h"
  34 #include "convert.h"
  35 #include "hash-map.h"
  36 #include "is-a.h"
  37 #include "plugin-api.h"
  38 #include "vec.h"
  39 #include "hashtab.h"
  40 #include "hash-set.h"
  41 #include "machmode.h"
  42 #include "hard-reg-set.h"
  43 #include "input.h"
  44 #include "function.h"
  45 #include "ipa-ref.h"
  46 #include "cgraph.h"
  47 #include "splay-tree.h"
  48 #include "hash-table.h"
  49 #include "gimple-expr.h"
  50 #include "gimplify.h"
  51 #include "wide-int.h"
  52
  53 static tree bot_manip (tree *, int *, void *);
  54 static tree bot_replace (tree *, int *, void *);
  55 static hashval_t list_hash_pieces (tree, tree, tree);
  56 static tree build_target_expr (tree, tree, tsubst_flags_t);
  57 static tree count_trees_r (tree *, int *, void *);
  58 static tree verify_stmt_tree_r (tree *, int *, void *);
  59 static tree build_local_temp (tree);
  60
  61 static tree handle_java_interface_decl_attribute (tree *, tree, tree, int,
  62                                                   bool *);
  63 static tree handle_java_interface_type_attribute (tree *, tree, tree, int,
  64                                                   bool *);
  65 static tree handle_com_interface_decl_attribute (tree *, tree, tree, int,
  66                                                  bool *);
  67 static tree handle_com_interface_type_attribute (tree *, tree, tree, int,
  68                                                  bool *);
  69 static tree handle_init_priority_attribute (tree *, tree, tree, int, bool *);
  70 static tree handle_abi_tag_decl_attribute (tree *, tree, tree, int, bool *);
  71 static tree handle_abi_tag_type_attribute (tree *, tree, tree, int, bool *);
  72
  73 /* If REF is an lvalue, returns the kind of lvalue that REF is.
  74    Otherwise, returns clk_none.  */
  75
  76 cp_lvalue_kind
  77 lvalue_kind (const_tree ref)
  78 {
  79   cp_lvalue_kind op1_lvalue_kind = clk_none;
  80   cp_lvalue_kind op2_lvalue_kind = clk_none;
  81
  82   /* Expressions of reference type are sometimes wrapped in
  83      INDIRECT_REFs.  INDIRECT_REFs are just internal compiler
  84      representation, not part of the language, so we have to look
  85      through them.  */
  86   if (REFERENCE_REF_P (ref))
  87     return lvalue_kind (TREE_OPERAND (ref, 0));
  88
  89   if (TREE_TYPE (ref)
  90       && TREE_CODE (TREE_TYPE (ref)) == REFERENCE_TYPE)
  91     {
  92       /* unnamed rvalue references are rvalues */
  93       if (TYPE_REF_IS_RVALUE (TREE_TYPE (ref))
  94           && TREE_CODE (ref) != PARM_DECL
  95           && !VAR_P (ref)
  96           && TREE_CODE (ref) != COMPONENT_REF
  97           /* Functions are always lvalues.  */
  98           && TREE_CODE (TREE_TYPE (TREE_TYPE (ref))) != FUNCTION_TYPE)
  99         return clk_rvalueref;
 100
 101       /* lvalue references and named rvalue references are lvalues.  */
 102       return clk_ordinary;
 103     }
 104
 105   if (ref == current_class_ptr)
 106     return clk_none;
 107
 108   switch (TREE_CODE (ref))
 109     {
 110     case SAVE_EXPR:
 111       return clk_none;
 112       /* preincrements and predecrements are valid lvals, provided
 113          what they refer to are valid lvals.  */
 114     case PREINCREMENT_EXPR:
 115     case PREDECREMENT_EXPR:
 116     case TRY_CATCH_EXPR:
 117     case WITH_CLEANUP_EXPR:
 118     case REALPART_EXPR:
 119     case IMAGPART_EXPR:
 120       return lvalue_kind (TREE_OPERAND (ref, 0));
 121
 122     case MEMBER_REF:
 123     case DOTSTAR_EXPR:
 124       if (TREE_CODE (ref) == MEMBER_REF)
 125         op1_lvalue_kind = clk_ordinary;
 126       else
 127         op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 0));
 128       if (TYPE_PTRMEMFUNC_P (TREE_TYPE (TREE_OPERAND (ref, 1))))
 129         op1_lvalue_kind = clk_none;
 130       return op1_lvalue_kind;
 131
 132     case COMPONENT_REF:
 133       op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 0));
 134       /* Look at the member designator.  */
 135       if (!op1_lvalue_kind)
 136         ;
 137       else if (is_overloaded_fn (TREE_OPERAND (ref, 1)))
 138         /* The "field" can be a FUNCTION_DECL or an OVERLOAD in some
 139            situations.  If we're seeing a COMPONENT_REF, it's a non-static
 140            member, so it isn't an lvalue. */
 141         op1_lvalue_kind = clk_none;
 142       else if (TREE_CODE (TREE_OPERAND (ref, 1)) != FIELD_DECL)
 143         /* This can be IDENTIFIER_NODE in a template.  */;
 144       else if (DECL_C_BIT_FIELD (TREE_OPERAND (ref, 1)))
 145         {
 146           /* Clear the ordinary bit.  If this object was a class
 147              rvalue we want to preserve that information.  */
 148           op1_lvalue_kind &= ~clk_ordinary;
 149           /* The lvalue is for a bitfield.  */
 150           op1_lvalue_kind |= clk_bitfield;
 151         }
 152       else if (DECL_PACKED (TREE_OPERAND (ref, 1)))
 153         op1_lvalue_kind |= clk_packed;
 154
 155       return op1_lvalue_kind;
 156
 157     case STRING_CST:
 158     case COMPOUND_LITERAL_EXPR:
 159       return clk_ordinary;
 160
 161     case CONST_DECL:
 162       /* CONST_DECL without TREE_STATIC are enumeration values and
 163          thus not lvalues.  With TREE_STATIC they are used by ObjC++
 164          in objc_build_string_object and need to be considered as
 165          lvalues.  */
 166       if (! TREE_STATIC (ref))
 167         return clk_none;
 168     case VAR_DECL:
 169       if (TREE_READONLY (ref) && ! TREE_STATIC (ref)
 170           && DECL_LANG_SPECIFIC (ref)
 171           && DECL_IN_AGGR_P (ref))
 172         return clk_none;
 173     case INDIRECT_REF:
 174     case ARROW_EXPR:
 175     case ARRAY_REF:
 176     case ARRAY_NOTATION_REF:
 177     case PARM_DECL:
 178     case RESULT_DECL:
 179     case PLACEHOLDER_EXPR:
 180       return clk_ordinary;
 181
 182       /* A scope ref in a template, left as SCOPE_REF to support later
 183          access checking.  */
 184     case SCOPE_REF:
 185       gcc_assert (!type_dependent_expression_p (CONST_CAST_TREE (ref)));
 186       {
 187         tree op = TREE_OPERAND (ref, 1);
 188         if (TREE_CODE (op) == FIELD_DECL)
 189           return (DECL_C_BIT_FIELD (op) ? clk_bitfield : clk_ordinary);
 190         else
 191           return lvalue_kind (op);
 192       }
 193
 194     case MAX_EXPR:
 195     case MIN_EXPR:
 196       /* Disallow <? and >? as lvalues if either argument side-effects.  */
 197       if (TREE_SIDE_EFFECTS (TREE_OPERAND (ref, 0))
 198           || TREE_SIDE_EFFECTS (TREE_OPERAND (ref, 1)))
 199         return clk_none;
 200       op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 0));
 201       op2_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 1));
 202       break;
 203
 204     case COND_EXPR:
 205       op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 1)
 206                                     ? TREE_OPERAND (ref, 1)
 207                                     : TREE_OPERAND (ref, 0));
 208       op2_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 2));
 209       break;
 210
 211     case MODIFY_EXPR:
 212     case TYPEID_EXPR:
 213       return clk_ordinary;
 214
 215     case COMPOUND_EXPR:
 216       return lvalue_kind (TREE_OPERAND (ref, 1));
 217
 218     case TARGET_EXPR:
 219       return clk_class;
 220
 221     case VA_ARG_EXPR:
 222       return (CLASS_TYPE_P (TREE_TYPE (ref)) ? clk_class : clk_none);
 223
 224     case CALL_EXPR:
 225       /* We can see calls outside of TARGET_EXPR in templates.  */
 226       if (CLASS_TYPE_P (TREE_TYPE (ref)))
 227         return clk_class;
 228       return clk_none;
 229
 230     case FUNCTION_DECL:
 231       /* All functions (except non-static-member functions) are
 232          lvalues.  */
 233       return (DECL_NONSTATIC_MEMBER_FUNCTION_P (ref)
 234               ? clk_none : clk_ordinary);
 235
 236     case BASELINK:
 237       /* We now represent a reference to a single static member function
 238          with a BASELINK.  */
 239       /* This CONST_CAST is okay because BASELINK_FUNCTIONS returns
 240          its argument unmodified and we assign it to a const_tree.  */
 241       return lvalue_kind (BASELINK_FUNCTIONS (CONST_CAST_TREE (ref)));
 242
 243     case NON_DEPENDENT_EXPR:
 244       /* We just return clk_ordinary for NON_DEPENDENT_EXPR in C++98, but
 245          in C++11 lvalues don't bind to rvalue references, so we need to
 246          work harder to avoid bogus errors (c++/44870).  */
 247       if (cxx_dialect < cxx11)
 248         return clk_ordinary;
 249       else
 250         return lvalue_kind (TREE_OPERAND (ref, 0));
 251
 252     default:
 253       if (!TREE_TYPE (ref))
 254         return clk_none;
 255       if (CLASS_TYPE_P (TREE_TYPE (ref)))
 256         return clk_class;
 257       break;
 258     }
 259
 260   /* If one operand is not an lvalue at all, then this expression is
 261      not an lvalue.  */
 262   if (!op1_lvalue_kind || !op2_lvalue_kind)
 263     return clk_none;
 264
 265   /* Otherwise, it's an lvalue, and it has all the odd properties
 266      contributed by either operand.  */
 267   op1_lvalue_kind = op1_lvalue_kind | op2_lvalue_kind;
 268   /* It's not an ordinary lvalue if it involves any other kind.  */
 269   if ((op1_lvalue_kind & ~clk_ordinary) != clk_none)
 270     op1_lvalue_kind &= ~clk_ordinary;
 271   /* It can't be both a pseudo-lvalue and a non-addressable lvalue.
 272      A COND_EXPR of those should be wrapped in a TARGET_EXPR.  */
 273   if ((op1_lvalue_kind & (clk_rvalueref|clk_class))
 274       && (op1_lvalue_kind & (clk_bitfield|clk_packed)))
 275     op1_lvalue_kind = clk_none;
 276   return op1_lvalue_kind;
 277 }
 278
 279 /* Returns the kind of lvalue that REF is, in the sense of
 280    [basic.lval].  This function should really be named lvalue_p; it
 281    computes the C++ definition of lvalue.  */
 282
 283 cp_lvalue_kind
 284 real_lvalue_p (const_tree ref)
 285 {
 286   cp_lvalue_kind kind = lvalue_kind (ref);
 287   if (kind & (clk_rvalueref|clk_class))
 288     return clk_none;
 289   else
 290     return kind;
 291 }
 292
 293 /* This differs from real_lvalue_p in that class rvalues are considered
 294    lvalues.  */
 295
 296 bool
 297 lvalue_p (const_tree ref)
 298 {
 299   return (lvalue_kind (ref) != clk_none);
 300 }
 301
 302 /* This differs from real_lvalue_p in that rvalues formed by dereferencing
 303    rvalue references are considered rvalues.  */
 304
 305 bool
 306 lvalue_or_rvalue_with_address_p (const_tree ref)
 307 {
 308   cp_lvalue_kind kind = lvalue_kind (ref);
 309   if (kind & clk_class)
 310     return false;
 311   else
 312     return (kind != clk_none);
 313 }
 314
 315 /* Returns true if REF is an xvalue, false otherwise.  */
 316
 317 bool
 318 xvalue_p (const_tree ref)
 319 {
 320   return (lvalue_kind (ref) == clk_rvalueref);
 321 }
 322
 323 /* Test whether DECL is a builtin that may appear in a
 324    constant-expression. */
 325
 326 bool
 327 builtin_valid_in_constant_expr_p (const_tree decl)
 328 {
 329   /* At present BUILT_IN_CONSTANT_P is the only builtin we're allowing
 330      in constant-expressions.  We may want to add other builtins later. */
 331   return DECL_IS_BUILTIN_CONSTANT_P (decl);
 332 }
 333
 334 /* Build a TARGET_EXPR, initializing the DECL with the VALUE.  */
 335
 336 static tree
 337 build_target_expr (tree decl, tree value, tsubst_flags_t complain)
 338 {
 339   tree t;
 340   tree type = TREE_TYPE (decl);
 341
 342 #ifdef ENABLE_CHECKING
 343   gcc_assert (VOID_TYPE_P (TREE_TYPE (value))
 344               || TREE_TYPE (decl) == TREE_TYPE (value)
 345               /* On ARM ctors return 'this'.  */
 346               || (TYPE_PTR_P (TREE_TYPE (value))
 347                   && TREE_CODE (value) == CALL_EXPR)
 348               || useless_type_conversion_p (TREE_TYPE (decl),
 349                                             TREE_TYPE (value)));
 350 #endif
 351
 352   t = cxx_maybe_build_cleanup (decl, complain);
 353   if (t == error_mark_node)
 354     return error_mark_node;
 355   t = build4 (TARGET_EXPR, type, decl, value, t, NULL_TREE);
 356   /* We always set TREE_SIDE_EFFECTS so that expand_expr does not
 357      ignore the TARGET_EXPR.  If there really turn out to be no
 358      side-effects, then the optimizer should be able to get rid of
 359      whatever code is generated anyhow.  */
 360   TREE_SIDE_EFFECTS (t) = 1;
 361
 362   return t;
 363 }
 364
 365 /* Return an undeclared local temporary of type TYPE for use in building a
 366    TARGET_EXPR.  */
 367
 368 static tree
 369 build_local_temp (tree type)
 370 {
 371   tree slot = build_decl (input_location,
 372                           VAR_DECL, NULL_TREE, type);
 373   DECL_ARTIFICIAL (slot) = 1;
 374   DECL_IGNORED_P (slot) = 1;
 375   DECL_CONTEXT (slot) = current_function_decl;
 376   layout_decl (slot, 0);
 377   return slot;
 378 }
 379
 380 /* Set various status flags when building an AGGR_INIT_EXPR object T.  */
 381
 382 static void
 383 process_aggr_init_operands (tree t)
 384 {
 385   bool side_effects;
 386
 387   side_effects = TREE_SIDE_EFFECTS (t);
 388   if (!side_effects)
 389     {
 390       int i, n;
 391       n = TREE_OPERAND_LENGTH (t);
 392       for (i = 1; i < n; i++)
 393         {
 394           tree op = TREE_OPERAND (t, i);
 395           if (op && TREE_SIDE_EFFECTS (op))
 396             {
 397               side_effects = 1;
 398               break;
 399             }
 400         }
 401     }
 402   TREE_SIDE_EFFECTS (t) = side_effects;
 403 }
 404
 405 /* Build an AGGR_INIT_EXPR of class tcc_vl_exp with the indicated RETURN_TYPE,
 406    FN, and SLOT.  NARGS is the number of call arguments which are specified
 407    as a tree array ARGS.  */
 408
 409 static tree
 410 build_aggr_init_array (tree return_type, tree fn, tree slot, int nargs,
 411                        tree *args)
 412 {
 413   tree t;
 414   int i;
 415
 416   t = build_vl_exp (AGGR_INIT_EXPR, nargs + 3);
 417   TREE_TYPE (t) = return_type;
 418   AGGR_INIT_EXPR_FN (t) = fn;
 419   AGGR_INIT_EXPR_SLOT (t) = slot;
 420   for (i = 0; i < nargs; i++)
 421     AGGR_INIT_EXPR_ARG (t, i) = args[i];
 422   process_aggr_init_operands (t);
 423   return t;
 424 }
 425
 426 /* INIT is a CALL_EXPR or AGGR_INIT_EXPR which needs info about its
 427    target.  TYPE is the type to be initialized.
 428
 429    Build an AGGR_INIT_EXPR to represent the initialization.  This function
 430    differs from build_cplus_new in that an AGGR_INIT_EXPR can only be used
 431    to initialize another object, whereas a TARGET_EXPR can either
 432    initialize another object or create its own temporary object, and as a
 433    result building up a TARGET_EXPR requires that the type's destructor be
 434    callable.  */
 435
 436 tree
 437 build_aggr_init_expr (tree type, tree init)
 438 {
 439   tree fn;
 440   tree slot;
 441   tree rval;
 442   int is_ctor;
 443
 444   /* Don't build AGGR_INIT_EXPR in a template.  */
 445   if (processing_template_decl)
 446     return init;
 447
 448   if (TREE_CODE (init) == CALL_EXPR)
 449     fn = CALL_EXPR_FN (init);
 450   else if (TREE_CODE (init) == AGGR_INIT_EXPR)
 451     fn = AGGR_INIT_EXPR_FN (init);
 452   else
 453     return convert (type, init);
 454
 455   is_ctor = (TREE_CODE (fn) == ADDR_EXPR
 456              && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
 457              && DECL_CONSTRUCTOR_P (TREE_OPERAND (fn, 0)));
 458
 459   /* We split the CALL_EXPR into its function and its arguments here.
 460      Then, in expand_expr, we put them back together.  The reason for
 461      this is that this expression might be a default argument
 462      expression.  In that case, we need a new temporary every time the
 463      expression is used.  That's what break_out_target_exprs does; it
 464      replaces every AGGR_INIT_EXPR with a copy that uses a fresh
 465      temporary slot.  Then, expand_expr builds up a call-expression
 466      using the new slot.  */
 467
 468   /* If we don't need to use a constructor to create an object of this
 469      type, don't mess with AGGR_INIT_EXPR.  */
 470   if (is_ctor || TREE_ADDRESSABLE (type))
 471     {
 472       slot = build_local_temp (type);
 473
 474       if (TREE_CODE(init) == CALL_EXPR)
 475         rval = build_aggr_init_array (void_type_node, fn, slot,
 476                                       call_expr_nargs (init),
 477                                       CALL_EXPR_ARGP (init));
 478       else
 479         rval = build_aggr_init_array (void_type_node, fn, slot,
 480                                       aggr_init_expr_nargs (init),
 481                                       AGGR_INIT_EXPR_ARGP (init));
 482       TREE_SIDE_EFFECTS (rval) = 1;
 483       AGGR_INIT_VIA_CTOR_P (rval) = is_ctor;
 484       TREE_NOTHROW (rval) = TREE_NOTHROW (init);
 485       CALL_EXPR_LIST_INIT_P (rval) = CALL_EXPR_LIST_INIT_P (init);
 486     }
 487   else
 488     rval = init;
 489
 490   return rval;
 491 }
 492
 493 /* INIT is a CALL_EXPR or AGGR_INIT_EXPR which needs info about its
 494    target.  TYPE is the type that this initialization should appear to
 495    have.
 496
 497    Build an encapsulation of the initialization to perform
 498    and return it so that it can be processed by language-independent
 499    and language-specific expression expanders.  */
 500
 501 tree
 502 build_cplus_new (tree type, tree init, tsubst_flags_t complain)
 503 {
 504   tree rval = build_aggr_init_expr (type, init);
 505   tree slot;
 506
 507   if (!complete_type_or_maybe_complain (type, init, complain))
 508     return error_mark_node;
 509
 510   /* Make sure that we're not trying to create an instance of an
 511      abstract class.  */
 512   if (abstract_virtuals_error_sfinae (NULL_TREE, type, complain))
 513     return error_mark_node;
 514
 515   if (TREE_CODE (rval) == AGGR_INIT_EXPR)
 516     slot = AGGR_INIT_EXPR_SLOT (rval);
 517   else if (TREE_CODE (rval) == CALL_EXPR
 518            || TREE_CODE (rval) == CONSTRUCTOR)
 519     slot = build_local_temp (type);
 520   else
 521     return rval;
 522
 523   rval = build_target_expr (slot, rval, complain);
 524
 525   if (rval != error_mark_node)
 526     TARGET_EXPR_IMPLICIT_P (rval) = 1;
 527
 528   return rval;
 529 }
 530
 531 /* Subroutine of build_vec_init_expr: Build up a single element
 532    intialization as a proxy for the full array initialization to get things
 533    marked as used and any appropriate diagnostics.
 534
 535    Since we're deferring building the actual constructor calls until
 536    gimplification time, we need to build one now and throw it away so
 537    that the relevant constructor gets mark_used before cgraph decides
 538    what functions are needed.  Here we assume that init is either
 539    NULL_TREE, void_type_node (indicating value-initialization), or
 540    another array to copy.  */
 541
 542 static tree
 543 build_vec_init_elt (tree type, tree init, tsubst_flags_t complain)
 544 {
 545   tree inner_type = strip_array_types (type);
 546   vec<tree, va_gc> *argvec;
 547
 548   if (integer_zerop (array_type_nelts_total (type))
 549       || !CLASS_TYPE_P (inner_type))
 550     /* No interesting initialization to do.  */
 551     return integer_zero_node;
 552   else if (init == void_type_node)
 553     return build_value_init (inner_type, complain);
 554
 555   gcc_assert (init == NULL_TREE
 556               || (same_type_ignoring_top_level_qualifiers_p
 557                   (type, TREE_TYPE (init))));
 558
 559   argvec = make_tree_vector ();
 560   if (init)
 561     {
 562       tree init_type = strip_array_types (TREE_TYPE (init));
 563       tree dummy = build_dummy_object (init_type);
 564       if (!real_lvalue_p (init))
 565         dummy = move (dummy);
 566       argvec->quick_push (dummy);
 567     }
 568   init = build_special_member_call (NULL_TREE, complete_ctor_identifier,
 569                                     &argvec, inner_type, LOOKUP_NORMAL,
 570                                     complain);
 571   release_tree_vector (argvec);
 572
 573   /* For a trivial constructor, build_over_call creates a TARGET_EXPR.  But
 574      we don't want one here because we aren't creating a temporary.  */
 575   if (TREE_CODE (init) == TARGET_EXPR)
 576     init = TARGET_EXPR_INITIAL (init);
 577
 578   return init;
 579 }
 580
 581 /* Return a TARGET_EXPR which expresses the initialization of an array to
 582    be named later, either default-initialization or copy-initialization
 583    from another array of the same type.  */
 584
 585 tree
 586 build_vec_init_expr (tree type, tree init, tsubst_flags_t complain)
 587 {
 588   tree slot;
 589   bool value_init = false;
 590   tree elt_init = build_vec_init_elt (type, init, complain);
 591
 592   if (init == void_type_node)
 593     {
 594       value_init = true;
 595       init = NULL_TREE;
 596     }
 597
 598   slot = build_local_temp (type);
 599   init = build2 (VEC_INIT_EXPR, type, slot, init);
 600   TREE_SIDE_EFFECTS (init) = true;
 601   SET_EXPR_LOCATION (init, input_location);
 602
 603   if (cxx_dialect >= cxx11
 604       && potential_constant_expression (elt_init))
 605     VEC_INIT_EXPR_IS_CONSTEXPR (init) = true;
 606   VEC_INIT_EXPR_VALUE_INIT (init) = value_init;
 607
 608   return init;
 609 }
 610
 611 /* Give a helpful diagnostic for a non-constexpr VEC_INIT_EXPR in a context
 612    that requires a constant expression.  */
 613
 614 void
 615 diagnose_non_constexpr_vec_init (tree expr)
 616 {
 617   tree type = TREE_TYPE (VEC_INIT_EXPR_SLOT (expr));
 618   tree init, elt_init;
 619   if (VEC_INIT_EXPR_VALUE_INIT (expr))
 620     init = void_type_node;
 621   else
 622     init = VEC_INIT_EXPR_INIT (expr);
 623
 624   elt_init = build_vec_init_elt (type, init, tf_warning_or_error);
 625   require_potential_constant_expression (elt_init);
 626 }
 627
 628 tree
 629 build_array_copy (tree init)
 630 {
 631   return build_vec_init_expr (TREE_TYPE (init), init, tf_warning_or_error);
 632 }
 633
 634 /* Build a TARGET_EXPR using INIT to initialize a new temporary of the
 635    indicated TYPE.  */
 636
 637 tree
 638 build_target_expr_with_type (tree init, tree type, tsubst_flags_t complain)
 639 {
 640   gcc_assert (!VOID_TYPE_P (type));
 641
 642   if (TREE_CODE (init) == TARGET_EXPR
 643       || init == error_mark_node)
 644     return init;
 645   else if (CLASS_TYPE_P (type) && type_has_nontrivial_copy_init (type)
 646            && !VOID_TYPE_P (TREE_TYPE (init))
 647            && TREE_CODE (init) != COND_EXPR
 648            && TREE_CODE (init) != CONSTRUCTOR
 649            && TREE_CODE (init) != VA_ARG_EXPR)
 650     /* We need to build up a copy constructor call.  A void initializer
 651        means we're being called from bot_manip.  COND_EXPR is a special
 652        case because we already have copies on the arms and we don't want
 653        another one here.  A CONSTRUCTOR is aggregate initialization, which
 654        is handled separately.  A VA_ARG_EXPR is magic creation of an
 655        aggregate; there's no additional work to be done.  */
 656     return force_rvalue (init, complain);
 657
 658   return force_target_expr (type, init, complain);
 659 }
 660
 661 /* Like the above function, but without the checking.  This function should
 662    only be used by code which is deliberately trying to subvert the type
 663    system, such as call_builtin_trap.  Or build_over_call, to avoid
 664    infinite recursion.  */
 665
 666 tree
 667 force_target_expr (tree type, tree init, tsubst_flags_t complain)
 668 {
 669   tree slot;
 670
 671   gcc_assert (!VOID_TYPE_P (type));
 672
 673   slot = build_local_temp (type);
 674   return build_target_expr (slot, init, complain);
 675 }
 676
 677 /* Like build_target_expr_with_type, but use the type of INIT.  */
 678
 679 tree
 680 get_target_expr_sfinae (tree init, tsubst_flags_t complain)
 681 {
 682   if (TREE_CODE (init) == AGGR_INIT_EXPR)
 683     return build_target_expr (AGGR_INIT_EXPR_SLOT (init), init, complain);
 684   else if (TREE_CODE (init) == VEC_INIT_EXPR)
 685     return build_target_expr (VEC_INIT_EXPR_SLOT (init), init, complain);
 686   else
 687     return build_target_expr_with_type (init, TREE_TYPE (init), complain);
 688 }
 689
 690 tree
 691 get_target_expr (tree init)
 692 {
 693   return get_target_expr_sfinae (init, tf_warning_or_error);
 694 }
 695
 696 /* If EXPR is a bitfield reference, convert it to the declared type of
 697    the bitfield, and return the resulting expression.  Otherwise,
 698    return EXPR itself.  */
 699
 700 tree
 701 convert_bitfield_to_declared_type (tree expr)
 702 {
 703   tree bitfield_type;
 704
 705   bitfield_type = is_bitfield_expr_with_lowered_type (expr);
 706   if (bitfield_type)
 707     expr = convert_to_integer (TYPE_MAIN_VARIANT (bitfield_type),
 708                                expr);
 709   return expr;
 710 }
 711
 712 /* EXPR is being used in an rvalue context.  Return a version of EXPR
 713    that is marked as an rvalue.  */
 714
 715 tree
 716 rvalue (tree expr)
 717 {
 718   tree type;
 719
 720   if (error_operand_p (expr))
 721     return expr;
 722
 723   expr = mark_rvalue_use (expr);
 724
 725   /* [basic.lval]
 726
 727      Non-class rvalues always have cv-unqualified types.  */
 728   type = TREE_TYPE (expr);
 729   if (!CLASS_TYPE_P (type) && cv_qualified_p (type))
 730     type = cv_unqualified (type);
 731
 732   /* We need to do this for rvalue refs as well to get the right answer
 733      from decltype; see c++/36628.  */
 734   if (!processing_template_decl && lvalue_or_rvalue_with_address_p (expr))
 735     expr = build1 (NON_LVALUE_EXPR, type, expr);
 736   else if (type != TREE_TYPE (expr))
 737     expr = build_nop (type, expr);
 738
 739   return expr;
 740 }
 741
 742 \f
 743 struct cplus_array_info
 744 {
 745   tree type;
 746   tree domain;
 747 };
 748
 749 struct cplus_array_hasher : ggc_hasher<tree>
 750 {
 751   typedef cplus_array_info *compare_type;
 752
 753   static hashval_t hash (tree t);
 754   static bool equal (tree, cplus_array_info *);
 755 };
 756
 757 /* Hash an ARRAY_TYPE.  K is really of type `tree'.  */
 758
 759 hashval_t
 760 cplus_array_hasher::hash (tree t)
 761 {
 762   hashval_t hash;
 763
 764   hash = TYPE_UID (TREE_TYPE (t));
 765   if (TYPE_DOMAIN (t))
 766     hash ^= TYPE_UID (TYPE_DOMAIN (t));
 767   return hash;
 768 }
 769
 770 /* Compare two ARRAY_TYPEs.  K1 is really of type `tree', K2 is really
 771    of type `cplus_array_info*'. */
 772
 773 bool
 774 cplus_array_hasher::equal (tree t1, cplus_array_info *t2)
 775 {
 776   return (TREE_TYPE (t1) == t2->type && TYPE_DOMAIN (t1) == t2->domain);
 777 }
 778
 779 /* Hash table containing dependent array types, which are unsuitable for
 780    the language-independent type hash table.  */
 781 static GTY (()) hash_table<cplus_array_hasher> *cplus_array_htab;
 782
 783 /* Build an ARRAY_TYPE without laying it out.  */
 784
 785 static tree
 786 build_min_array_type (tree elt_type, tree index_type)
 787 {
 788   tree t = cxx_make_type (ARRAY_TYPE);
 789   TREE_TYPE (t) = elt_type;
 790   TYPE_DOMAIN (t) = index_type;
 791   return t;
 792 }
 793
 794 /* Set TYPE_CANONICAL like build_array_type_1, but using
 795    build_cplus_array_type.  */
 796
 797 static void
 798 set_array_type_canon (tree t, tree elt_type, tree index_type)
 799 {
 800   /* Set the canonical type for this new node.  */
 801   if (TYPE_STRUCTURAL_EQUALITY_P (elt_type)
 802       || (index_type && TYPE_STRUCTURAL_EQUALITY_P (index_type)))
 803     SET_TYPE_STRUCTURAL_EQUALITY (t);
 804   else if (TYPE_CANONICAL (elt_type) != elt_type
 805            || (index_type && TYPE_CANONICAL (index_type) != index_type))
 806     TYPE_CANONICAL (t)
 807       = build_cplus_array_type (TYPE_CANONICAL (elt_type),
 808                                 index_type
 809                                 ? TYPE_CANONICAL (index_type) : index_type);
 810   else
 811     TYPE_CANONICAL (t) = t;
 812 }
 813
 814 /* Like build_array_type, but handle special C++ semantics: an array of a
 815    variant element type is a variant of the array of the main variant of
 816    the element type.  */
 817
 818 tree
 819 build_cplus_array_type (tree elt_type, tree index_type)
 820 {
 821   tree t;
 822
 823   if (elt_type == error_mark_node || index_type == error_mark_node)
 824     return error_mark_node;
 825
 826   bool dependent
 827     = (processing_template_decl
 828        && (dependent_type_p (elt_type)
 829            || (index_type && !TREE_CONSTANT (TYPE_MAX_VALUE (index_type)))));
 830
 831   if (elt_type != TYPE_MAIN_VARIANT (elt_type))
 832     /* Start with an array of the TYPE_MAIN_VARIANT.  */
 833     t = build_cplus_array_type (TYPE_MAIN_VARIANT (elt_type),
 834                                 index_type);
 835   else if (dependent)
 836     {
 837       /* Since type_hash_canon calls layout_type, we need to use our own
 838          hash table.  */
 839       cplus_array_info cai;
 840       hashval_t hash;
 841
 842       if (cplus_array_htab == NULL)
 843         cplus_array_htab = hash_table<cplus_array_hasher>::create_ggc (61);
 844
 845       hash = TYPE_UID (elt_type);
 846       if (index_type)
 847         hash ^= TYPE_UID (index_type);
 848       cai.type = elt_type;
 849       cai.domain = index_type;
 850
 851       tree *e = cplus_array_htab->find_slot_with_hash (&cai, hash, INSERT);
 852       if (*e)
 853         /* We have found the type: we're done.  */
 854         return (tree) *e;
 855       else
 856         {
 857           /* Build a new array type.  */
 858           t = build_min_array_type (elt_type, index_type);
 859
 860           /* Store it in the hash table. */
 861           *e = t;
 862
 863           /* Set the canonical type for this new node.  */
 864           set_array_type_canon (t, elt_type, index_type);
 865         }
 866     }
 867   else
 868     {
 869       t = build_array_type (elt_type, index_type);
 870     }
 871
 872   /* Now check whether we already have this array variant.  */
 873   if (elt_type != TYPE_MAIN_VARIANT (elt_type))
 874     {
 875       tree m = t;
 876       for (t = m; t; t = TYPE_NEXT_VARIANT (t))
 877         if (TREE_TYPE (t) == elt_type
 878             && TYPE_NAME (t) == NULL_TREE
 879             && TYPE_ATTRIBUTES (t) == NULL_TREE)
 880           break;
 881       if (!t)
 882         {
 883           t = build_min_array_type (elt_type, index_type);
 884           set_array_type_canon (t, elt_type, index_type);
 885           if (!dependent)
 886             layout_type (t);
 887
 888           TYPE_MAIN_VARIANT (t) = m;
 889           TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
 890           TYPE_NEXT_VARIANT (m) = t;
 891         }
 892     }
 893
 894   /* Avoid spurious warnings with VLAs (c++/54583).  */
 895   if (TYPE_SIZE (t) && EXPR_P (TYPE_SIZE (t)))
 896     TREE_NO_WARNING (TYPE_SIZE (t)) = 1;
 897
 898   /* Push these needs up to the ARRAY_TYPE so that initialization takes
 899      place more easily.  */
 900   bool needs_ctor = (TYPE_NEEDS_CONSTRUCTING (t)
 901                      = TYPE_NEEDS_CONSTRUCTING (elt_type));
 902   bool needs_dtor = (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
 903                      = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (elt_type));
 904
 905   if (!dependent && t == TYPE_MAIN_VARIANT (t)
 906       && !COMPLETE_TYPE_P (t) && COMPLETE_TYPE_P (elt_type))
 907     {
 908       /* The element type has been completed since the last time we saw
 909          this array type; update the layout and 'tor flags for any variants
 910          that need it.  */
 911       layout_type (t);
 912       for (tree v = TYPE_NEXT_VARIANT (t); v; v = TYPE_NEXT_VARIANT (v))
 913         {
 914           TYPE_NEEDS_CONSTRUCTING (v) = needs_ctor;
 915           TYPE_HAS_NONTRIVIAL_DESTRUCTOR (v) = needs_dtor;
 916         }
 917     }
 918
 919   return t;
 920 }
 921
 922 /* Return an ARRAY_TYPE with element type ELT and length N.  */
 923
 924 tree
 925 build_array_of_n_type (tree elt, int n)
 926 {
 927   return build_cplus_array_type (elt, build_index_type (size_int (n - 1)));
 928 }
 929
 930 /* True iff T is an N3639 array of runtime bound (VLA).  These were
 931    approved for C++14 but then removed.  */
 932
 933 bool
 934 array_of_runtime_bound_p (tree t)
 935 {
 936   if (!t || TREE_CODE (t) != ARRAY_TYPE)
 937     return false;
 938   tree dom = TYPE_DOMAIN (t);
 939   if (!dom)
 940     return false;
 941   tree max = TYPE_MAX_VALUE (dom);
 942   return (!potential_rvalue_constant_expression (max)
 943           || (!value_dependent_expression_p (max) && !TREE_CONSTANT (max)));
 944 }
 945
 946 /* Return a reference type node referring to TO_TYPE.  If RVAL is
 947    true, return an rvalue reference type, otherwise return an lvalue
 948    reference type.  If a type node exists, reuse it, otherwise create
 949    a new one.  */
 950 tree
 951 cp_build_reference_type (tree to_type, bool rval)
 952 {
 953   tree lvalue_ref, t;
 954   lvalue_ref = build_reference_type (to_type);
 955   if (!rval)
 956     return lvalue_ref;
 957
 958   /* This code to create rvalue reference types is based on and tied
 959      to the code creating lvalue reference types in the middle-end
 960      functions build_reference_type_for_mode and build_reference_type.
 961
 962      It works by putting the rvalue reference type nodes after the
 963      lvalue reference nodes in the TYPE_NEXT_REF_TO linked list, so
 964      they will effectively be ignored by the middle end.  */
 965
 966   for (t = lvalue_ref; (t = TYPE_NEXT_REF_TO (t)); )
 967     if (TYPE_REF_IS_RVALUE (t))
 968       return t;
 969
 970   t = build_distinct_type_copy (lvalue_ref);
 971
 972   TYPE_REF_IS_RVALUE (t) = true;
 973   TYPE_NEXT_REF_TO (t) = TYPE_NEXT_REF_TO (lvalue_ref);
 974   TYPE_NEXT_REF_TO (lvalue_ref) = t;
 975
 976   if (TYPE_STRUCTURAL_EQUALITY_P (to_type))
 977     SET_TYPE_STRUCTURAL_EQUALITY (t);
 978   else if (TYPE_CANONICAL (to_type) != to_type)
 979     TYPE_CANONICAL (t)
 980       = cp_build_reference_type (TYPE_CANONICAL (to_type), rval);
 981   else
 982     TYPE_CANONICAL (t) = t;
 983
 984   layout_type (t);
 985
 986   return t;
 987
 988 }
 989
 990 /* Returns EXPR cast to rvalue reference type, like std::move.  */
 991
 992 tree
 993 move (tree expr)
 994 {
 995   tree type = TREE_TYPE (expr);
 996   gcc_assert (TREE_CODE (type) != REFERENCE_TYPE);
 997   type = cp_build_reference_type (type, /*rval*/true);
 998   return build_static_cast (type, expr, tf_warning_or_error);
 999 }
1000
1001 /* Used by the C++ front end to build qualified array types.  However,
1002    the C version of this function does not properly maintain canonical
1003    types (which are not used in C).  */
1004 tree
1005 c_build_qualified_type (tree type, int type_quals)
1006 {
1007   return cp_build_qualified_type (type, type_quals);
1008 }
1009
1010 \f
1011 /* Make a variant of TYPE, qualified with the TYPE_QUALS.  Handles
1012    arrays correctly.  In particular, if TYPE is an array of T's, and
1013    TYPE_QUALS is non-empty, returns an array of qualified T's.
1014
1015    FLAGS determines how to deal with ill-formed qualifications. If
1016    tf_ignore_bad_quals is set, then bad qualifications are dropped
1017    (this is permitted if TYPE was introduced via a typedef or template
1018    type parameter). If bad qualifications are dropped and tf_warning
1019    is set, then a warning is issued for non-const qualifications.  If
1020    tf_ignore_bad_quals is not set and tf_error is not set, we
1021    return error_mark_node. Otherwise, we issue an error, and ignore
1022    the qualifications.
1023
1024    Qualification of a reference type is valid when the reference came
1025    via a typedef or template type argument. [dcl.ref] No such
1026    dispensation is provided for qualifying a function type.  [dcl.fct]
1027    DR 295 queries this and the proposed resolution brings it into line
1028    with qualifying a reference.  We implement the DR.  We also behave
1029    in a similar manner for restricting non-pointer types.  */
1030
1031 tree
1032 cp_build_qualified_type_real (tree type,
1033                               int type_quals,
1034                               tsubst_flags_t complain)
1035 {
1036   tree result;
1037   int bad_quals = TYPE_UNQUALIFIED;
1038
1039   if (type == error_mark_node)
1040     return type;
1041
1042   if (type_quals == cp_type_quals (type))
1043     return type;
1044
1045   if (TREE_CODE (type) == ARRAY_TYPE)
1046     {
1047       /* In C++, the qualification really applies to the array element
1048          type.  Obtain the appropriately qualified element type.  */
1049       tree t;
1050       tree element_type
1051         = cp_build_qualified_type_real (TREE_TYPE (type),
1052                                         type_quals,
1053                                         complain);
1054
1055       if (element_type == error_mark_node)
1056         return error_mark_node;
1057
1058       /* See if we already have an identically qualified type.  Tests
1059          should be equivalent to those in check_qualified_type.  */
1060       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
1061         if (TREE_TYPE (t) == element_type
1062             && TYPE_NAME (t) == TYPE_NAME (type)
1063             && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
1064             && attribute_list_equal (TYPE_ATTRIBUTES (t),
1065                                      TYPE_ATTRIBUTES (type)))
1066           break;
1067
1068       if (!t)
1069         {
1070           t = build_cplus_array_type (element_type, TYPE_DOMAIN (type));
1071
1072           /* Keep the typedef name.  */
1073           if (TYPE_NAME (t) != TYPE_NAME (type))
1074             {
1075               t = build_variant_type_copy (t);
1076               TYPE_NAME (t) = TYPE_NAME (type);
1077             }
1078         }
1079
1080       /* Even if we already had this variant, we update
1081          TYPE_NEEDS_CONSTRUCTING and TYPE_HAS_NONTRIVIAL_DESTRUCTOR in case
1082          they changed since the variant was originally created.
1083
1084          This seems hokey; if there is some way to use a previous
1085          variant *without* coming through here,
1086          TYPE_NEEDS_CONSTRUCTING will never be updated.  */
1087       TYPE_NEEDS_CONSTRUCTING (t)
1088         = TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (element_type));
1089       TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
1090         = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TYPE_MAIN_VARIANT (element_type));
1091       return t;
1092     }
1093   else if (TREE_CODE (type) == TYPE_PACK_EXPANSION)
1094     {
1095       tree t = PACK_EXPANSION_PATTERN (type);
1096
1097       t = cp_build_qualified_type_real (t, type_quals, complain);
1098       return make_pack_expansion (t);
1099     }
1100
1101   /* A reference or method type shall not be cv-qualified.
1102      [dcl.ref], [dcl.fct].  This used to be an error, but as of DR 295
1103      (in CD1) we always ignore extra cv-quals on functions.  */
1104   if (type_quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE)
1105       && (TREE_CODE (type) == REFERENCE_TYPE
1106           || TREE_CODE (type) == FUNCTION_TYPE
1107           || TREE_CODE (type) == METHOD_TYPE))
1108     {
1109       if (TREE_CODE (type) == REFERENCE_TYPE)
1110         bad_quals |= type_quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE);
1111       type_quals &= ~(TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE);
1112     }
1113
1114   /* But preserve any function-cv-quals on a FUNCTION_TYPE.  */
1115   if (TREE_CODE (type) == FUNCTION_TYPE)
1116     type_quals |= type_memfn_quals (type);
1117
1118   /* A restrict-qualified type must be a pointer (or reference)
1119      to object or incomplete type. */
1120   if ((type_quals & TYPE_QUAL_RESTRICT)
1121       && TREE_CODE (type) != TEMPLATE_TYPE_PARM
1122       && TREE_CODE (type) != TYPENAME_TYPE
1123       && !POINTER_TYPE_P (type))
1124     {
1125       bad_quals |= TYPE_QUAL_RESTRICT;
1126       type_quals &= ~TYPE_QUAL_RESTRICT;
1127     }
1128
1129   if (bad_quals == TYPE_UNQUALIFIED
1130       || (complain & tf_ignore_bad_quals))
1131     /*OK*/;
1132   else if (!(complain & tf_error))
1133     return error_mark_node;
1134   else
1135     {
1136       tree bad_type = build_qualified_type (ptr_type_node, bad_quals);
1137       error ("%qV qualifiers cannot be applied to %qT",
1138              bad_type, type);
1139     }
1140
1141   /* Retrieve (or create) the appropriately qualified variant.  */
1142   result = build_qualified_type (type, type_quals);
1143
1144   /* Preserve exception specs and ref-qualifier since build_qualified_type
1145      doesn't know about them.  */
1146   if (TREE_CODE (result) == FUNCTION_TYPE
1147       || TREE_CODE (result) == METHOD_TYPE)
1148     {
1149       result = build_exception_variant (result, TYPE_RAISES_EXCEPTIONS (type));
1150       result = build_ref_qualified_type (result, type_memfn_rqual (type));
1151     }
1152
1153   return result;
1154 }
1155
1156 /* Return TYPE with const and volatile removed.  */
1157
1158 tree
1159 cv_unqualified (tree type)
1160 {
1161   int quals;
1162
1163   if (type == error_mark_node)
1164     return type;
1165
1166   quals = cp_type_quals (type);
1167   quals &= ~(TYPE_QUAL_CONST|TYPE_QUAL_VOLATILE);
1168   return cp_build_qualified_type (type, quals);
1169 }
1170
1171 /* Builds a qualified variant of T that is not a typedef variant.
1172    E.g. consider the following declarations:
1173      typedef const int ConstInt;
1174      typedef ConstInt* PtrConstInt;
1175    If T is PtrConstInt, this function returns a type representing
1176      const int*.
1177    In other words, if T is a typedef, the function returns the underlying type.
1178    The cv-qualification and attributes of the type returned match the
1179    input type.
1180    They will always be compatible types.
1181    The returned type is built so that all of its subtypes
1182    recursively have their typedefs stripped as well.
1183
1184    This is different from just returning TYPE_CANONICAL (T)
1185    Because of several reasons:
1186     * If T is a type that needs structural equality
1187       its TYPE_CANONICAL (T) will be NULL.
1188     * TYPE_CANONICAL (T) desn't carry type attributes
1189       and loses template parameter names.   */
1190
1191 tree
1192 strip_typedefs (tree t)
1193 {
1194   tree result = NULL, type = NULL, t0 = NULL;
1195
1196   if (!t || t == error_mark_node)
1197     return t;
1198
1199   if (TREE_CODE (t) == TREE_LIST)
1200     {
1201       bool changed = false;
1202       vec<tree,va_gc> *vec = make_tree_vector ();
1203       for (; t; t = TREE_CHAIN (t))
1204         {
1205           gcc_assert (!TREE_PURPOSE (t));
1206           tree elt = strip_typedefs (TREE_VALUE (t));
1207           if (elt != TREE_VALUE (t))
1208             changed = true;
1209           vec_safe_push (vec, elt);
1210         }
1211       tree r = t;
1212       if (changed)
1213         r = build_tree_list_vec (vec);
1214       release_tree_vector (vec);
1215       return r;
1216     }
1217
1218   gcc_assert (TYPE_P (t));
1219
1220   if (t == TYPE_CANONICAL (t))
1221     return t;
1222
1223   if (dependent_alias_template_spec_p (t))
1224     /* DR 1558: However, if the template-id is dependent, subsequent
1225        template argument substitution still applies to the template-id.  */
1226     return t;
1227
1228   switch (TREE_CODE (t))
1229     {
1230     case POINTER_TYPE:
1231       type = strip_typedefs (TREE_TYPE (t));
1232       result = build_pointer_type (type);
1233       break;
1234     case REFERENCE_TYPE:
1235       type = strip_typedefs (TREE_TYPE (t));
1236       result = cp_build_reference_type (type, TYPE_REF_IS_RVALUE (t));
1237       break;
1238     case OFFSET_TYPE:
1239       t0 = strip_typedefs (TYPE_OFFSET_BASETYPE (t));
1240       type = strip_typedefs (TREE_TYPE (t));
1241       result = build_offset_type (t0, type);
1242       break;
1243     case RECORD_TYPE:
1244       if (TYPE_PTRMEMFUNC_P (t))
1245         {
1246           t0 = strip_typedefs (TYPE_PTRMEMFUNC_FN_TYPE (t));
1247           result = build_ptrmemfunc_type (t0);
1248         }
1249       break;
1250     case ARRAY_TYPE:
1251       type = strip_typedefs (TREE_TYPE (t));
1252       t0  = strip_typedefs (TYPE_DOMAIN (t));;
1253       result = build_cplus_array_type (type, t0);
1254       break;
1255     case FUNCTION_TYPE:
1256     case METHOD_TYPE:
1257       {
1258         tree arg_types = NULL, arg_node, arg_type;
1259         for (arg_node = TYPE_ARG_TYPES (t);
1260              arg_node;
1261              arg_node = TREE_CHAIN (arg_node))
1262           {
1263             if (arg_node == void_list_node)
1264               break;
1265             arg_type = strip_typedefs (TREE_VALUE (arg_node));
1266             gcc_assert (arg_type);
1267
1268             arg_types =
1269               tree_cons (TREE_PURPOSE (arg_node), arg_type, arg_types);
1270           }
1271
1272         if (arg_types)
1273           arg_types = nreverse (arg_types);
1274
1275         /* A list of parameters not ending with an ellipsis
1276            must end with void_list_node.  */
1277         if (arg_node)
1278           arg_types = chainon (arg_types, void_list_node);
1279
1280         type = strip_typedefs (TREE_TYPE (t));
1281         if (TREE_CODE (t) == METHOD_TYPE)
1282           {
1283             tree class_type = TREE_TYPE (TREE_VALUE (arg_types));
1284             gcc_assert (class_type);
1285             result =
1286               build_method_type_directly (class_type, type,
1287                                           TREE_CHAIN (arg_types));
1288             result
1289               = build_ref_qualified_type (result, type_memfn_rqual (t));
1290           }
1291         else
1292           {
1293             result = build_function_type (type,
1294                                           arg_types);
1295             result = apply_memfn_quals (result,
1296                                         type_memfn_quals (t),
1297                                         type_memfn_rqual (t));
1298           }
1299
1300         if (TYPE_RAISES_EXCEPTIONS (t))
1301           result = build_exception_variant (result,
1302                                             TYPE_RAISES_EXCEPTIONS (t));
1303         if (TYPE_HAS_LATE_RETURN_TYPE (t))
1304           TYPE_HAS_LATE_RETURN_TYPE (result) = 1;
1305       }
1306       break;
1307     case TYPENAME_TYPE:
1308       {
1309         tree fullname = TYPENAME_TYPE_FULLNAME (t);
1310         if (TREE_CODE (fullname) == TEMPLATE_ID_EXPR
1311             && TREE_OPERAND (fullname, 1))
1312           {
1313             tree args = TREE_OPERAND (fullname, 1);
1314             tree new_args = copy_node (args);
1315             bool changed = false;
1316             for (int i = 0; i < TREE_VEC_LENGTH (args); ++i)
1317               {
1318                 tree arg = TREE_VEC_ELT (args, i);
1319                 tree strip_arg;
1320                 if (TYPE_P (arg))
1321                   strip_arg = strip_typedefs (arg);
1322                 else
1323                   strip_arg = strip_typedefs_expr (arg);
1324                 TREE_VEC_ELT (new_args, i) = strip_arg;
1325                 if (strip_arg != arg)
1326                   changed = true;
1327               }
1328             if (changed)
1329               {
1330                 NON_DEFAULT_TEMPLATE_ARGS_COUNT (new_args)
1331                   = NON_DEFAULT_TEMPLATE_ARGS_COUNT (args);
1332                 fullname
1333                   = lookup_template_function (TREE_OPERAND (fullname, 0),
1334                                               new_args);
1335               }
1336             else
1337               ggc_free (new_args);
1338           }
1339         result = make_typename_type (strip_typedefs (TYPE_CONTEXT (t)),
1340                                      fullname, typename_type, tf_none);
1341       }
1342       break;
1343     case DECLTYPE_TYPE:
1344       result = strip_typedefs_expr (DECLTYPE_TYPE_EXPR (t));
1345       if (result == DECLTYPE_TYPE_EXPR (t))
1346         return t;
1347       else
1348         result = (finish_decltype_type
1349                   (result,
1350                    DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t),
1351                    tf_none));
1352       break;
1353     default:
1354       break;
1355     }
1356
1357   if (!result)
1358       result = TYPE_MAIN_VARIANT (t);
1359   if (TYPE_USER_ALIGN (t) != TYPE_USER_ALIGN (result)
1360       || TYPE_ALIGN (t) != TYPE_ALIGN (result))
1361     {
1362       gcc_assert (TYPE_USER_ALIGN (t));
1363       if (TYPE_ALIGN (t) == TYPE_ALIGN (result))
1364         result = build_variant_type_copy (result);
1365       else
1366         result = build_aligned_type (result, TYPE_ALIGN (t));
1367       TYPE_USER_ALIGN (result) = true;
1368     }
1369   if (TYPE_ATTRIBUTES (t))
1370     result = cp_build_type_attribute_variant (result, TYPE_ATTRIBUTES (t));
1371   return cp_build_qualified_type (result, cp_type_quals (t));
1372 }
1373
1374 /* Like strip_typedefs above, but works on expressions, so that in
1375
1376    template<class T> struct A
1377    {
1378      typedef T TT;
1379      B<sizeof(TT)> b;
1380    };
1381
1382    sizeof(TT) is replaced by sizeof(T).  */
1383
1384 tree
1385 strip_typedefs_expr (tree t)
1386 {
1387   unsigned i,n;
1388   tree r, type, *ops;
1389   enum tree_code code;
1390
1391   if (t == NULL_TREE || t == error_mark_node)
1392     return t;
1393
1394   if (DECL_P (t) || CONSTANT_CLASS_P (t))
1395     return t;
1396
1397   /* Some expressions have type operands, so let's handle types here rather
1398      than check TYPE_P in multiple places below.  */
1399   if (TYPE_P (t))
1400     return strip_typedefs (t);
1401
1402   code = TREE_CODE (t);
1403   switch (code)
1404     {
1405     case IDENTIFIER_NODE:
1406     case TEMPLATE_PARM_INDEX:
1407     case OVERLOAD:
1408     case BASELINK:
1409     case ARGUMENT_PACK_SELECT:
1410       return t;
1411
1412     case TRAIT_EXPR:
1413       {
1414         tree type1 = strip_typedefs (TRAIT_EXPR_TYPE1 (t));
1415         tree type2 = strip_typedefs (TRAIT_EXPR_TYPE2 (t));
1416         if (type1 == TRAIT_EXPR_TYPE1 (t)
1417             && type2 == TRAIT_EXPR_TYPE2 (t))
1418           return t;
1419         r = copy_node (t);
1420         TRAIT_EXPR_TYPE1 (t) = type1;
1421         TRAIT_EXPR_TYPE2 (t) = type2;
1422         return r;
1423       }
1424
1425     case TREE_LIST:
1426       {
1427         vec<tree, va_gc> *vec = make_tree_vector ();
1428         bool changed = false;
1429         tree it;
1430         for (it = t; it; it = TREE_CHAIN (it))
1431           {
1432             tree val = strip_typedefs_expr (TREE_VALUE (t));
1433             vec_safe_push (vec, val);
1434             if (val != TREE_VALUE (t))
1435               changed = true;
1436             gcc_assert (TREE_PURPOSE (it) == NULL_TREE);
1437           }
1438         if (changed)
1439           {
1440             r = NULL_TREE;
1441             FOR_EACH_VEC_ELT_REVERSE (*vec, i, it)
1442               r = tree_cons (NULL_TREE, it, r);
1443           }
1444         else
1445           r = t;
1446         release_tree_vector (vec);
1447         return r;
1448       }
1449
1450     case TREE_VEC:
1451       {
1452         bool changed = false;
1453         vec<tree, va_gc> *vec = make_tree_vector ();
1454         n = TREE_VEC_LENGTH (t);
1455         vec_safe_reserve (vec, n);
1456         for (i = 0; i < n; ++i)
1457           {
1458             tree op = strip_typedefs_expr (TREE_VEC_ELT (t, i));
1459             vec->quick_push (op);
1460             if (op != TREE_VEC_ELT (t, i))
1461               changed = true;
1462           }
1463         if (changed)
1464           {
1465             r = copy_node (t);
1466             for (i = 0; i < n; ++i)
1467               TREE_VEC_ELT (r, i) = (*vec)[i];
1468             NON_DEFAULT_TEMPLATE_ARGS_COUNT (r)
1469               = NON_DEFAULT_TEMPLATE_ARGS_COUNT (t);
1470           }
1471         else
1472           r = t;
1473         release_tree_vector (vec);
1474         return r;
1475       }
1476
1477     case CONSTRUCTOR:
1478       {
1479         bool changed = false;
1480         vec<constructor_elt, va_gc> *vec
1481           = vec_safe_copy (CONSTRUCTOR_ELTS (t));
1482         n = CONSTRUCTOR_NELTS (t);
1483         type = strip_typedefs (TREE_TYPE (t));
1484         for (i = 0; i < n; ++i)
1485           {
1486             constructor_elt *e = &(*vec)[i];
1487             tree op = strip_typedefs_expr (e->value);
1488             if (op != e->value)
1489               {
1490                 changed = true;
1491                 e->value = op;
1492               }
1493             gcc_checking_assert (e->index == strip_typedefs_expr (e->index));
1494           }
1495
1496         if (!changed && type == TREE_TYPE (t))
1497           {
1498             vec_free (vec);
1499             return t;
1500           }
1501         else
1502           {
1503             r = copy_node (t);
1504             TREE_TYPE (r) = type;
1505             CONSTRUCTOR_ELTS (r) = vec;
1506             return r;
1507           }
1508       }
1509
1510     case LAMBDA_EXPR:
1511       error ("lambda-expression in a constant expression");
1512       return error_mark_node;
1513
1514     default:
1515       break;
1516     }
1517
1518   gcc_assert (EXPR_P (t));
1519
1520   n = TREE_OPERAND_LENGTH (t);
1521   ops = XALLOCAVEC (tree, n);
1522   type = TREE_TYPE (t);
1523
1524   switch (code)
1525     {
1526     CASE_CONVERT:
1527     case IMPLICIT_CONV_EXPR:
1528     case DYNAMIC_CAST_EXPR:
1529     case STATIC_CAST_EXPR:
1530     case CONST_CAST_EXPR:
1531     case REINTERPRET_CAST_EXPR:
1532     case CAST_EXPR:
1533     case NEW_EXPR:
1534       type = strip_typedefs (type);
1535       /* fallthrough */
1536
1537     default:
1538       for (i = 0; i < n; ++i)
1539         ops[i] = strip_typedefs_expr (TREE_OPERAND (t, i));
1540       break;
1541     }
1542
1543   /* If nothing changed, return t.  */
1544   for (i = 0; i < n; ++i)
1545     if (ops[i] != TREE_OPERAND (t, i))
1546       break;
1547   if (i == n && type == TREE_TYPE (t))
1548     return t;
1549
1550   r = copy_node (t);
1551   TREE_TYPE (r) = type;
1552   for (i = 0; i < n; ++i)
1553     TREE_OPERAND (r, i) = ops[i];
1554   return r;
1555 }
1556
1557 /* Makes a copy of BINFO and TYPE, which is to be inherited into a
1558    graph dominated by T.  If BINFO is NULL, TYPE is a dependent base,
1559    and we do a shallow copy.  If BINFO is non-NULL, we do a deep copy.
1560    VIRT indicates whether TYPE is inherited virtually or not.
1561    IGO_PREV points at the previous binfo of the inheritance graph
1562    order chain.  The newly copied binfo's TREE_CHAIN forms this
1563    ordering.
1564
1565    The CLASSTYPE_VBASECLASSES vector of T is constructed in the
1566    correct order. That is in the order the bases themselves should be
1567    constructed in.
1568
1569    The BINFO_INHERITANCE of a virtual base class points to the binfo
1570    of the most derived type. ??? We could probably change this so that
1571    BINFO_INHERITANCE becomes synonymous with BINFO_PRIMARY, and hence
1572    remove a field.  They currently can only differ for primary virtual
1573    virtual bases.  */
1574
1575 tree
1576 copy_binfo (tree binfo, tree type, tree t, tree *igo_prev, int virt)
1577 {
1578   tree new_binfo;
1579
1580   if (virt)
1581     {
1582       /* See if we've already made this virtual base.  */
1583       new_binfo = binfo_for_vbase (type, t);
1584       if (new_binfo)
1585         return new_binfo;
1586     }
1587
1588   new_binfo = make_tree_binfo (binfo ? BINFO_N_BASE_BINFOS (binfo) : 0);
1589   BINFO_TYPE (new_binfo) = type;
1590
1591   /* Chain it into the inheritance graph.  */
1592   TREE_CHAIN (*igo_prev) = new_binfo;
1593   *igo_prev = new_binfo;
1594
1595   if (binfo && !BINFO_DEPENDENT_BASE_P (binfo))
1596     {
1597       int ix;
1598       tree base_binfo;
1599
1600       gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), type));
1601
1602       BINFO_OFFSET (new_binfo) = BINFO_OFFSET (binfo);
1603       BINFO_VIRTUALS (new_binfo) = BINFO_VIRTUALS (binfo);
1604
1605       /* We do not need to copy the accesses, as they are read only.  */
1606       BINFO_BASE_ACCESSES (new_binfo) = BINFO_BASE_ACCESSES (binfo);
1607
1608       /* Recursively copy base binfos of BINFO.  */
1609       for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++)
1610         {
1611           tree new_base_binfo;
1612           new_base_binfo = copy_binfo (base_binfo, BINFO_TYPE (base_binfo),
1613                                        t, igo_prev,
1614                                        BINFO_VIRTUAL_P (base_binfo));
1615
1616           if (!BINFO_INHERITANCE_CHAIN (new_base_binfo))
1617             BINFO_INHERITANCE_CHAIN (new_base_binfo) = new_binfo;
1618           BINFO_BASE_APPEND (new_binfo, new_base_binfo);
1619         }
1620     }
1621   else
1622     BINFO_DEPENDENT_BASE_P (new_binfo) = 1;
1623
1624   if (virt)
1625     {
1626       /* Push it onto the list after any virtual bases it contains
1627          will have been pushed.  */
1628       CLASSTYPE_VBASECLASSES (t)->quick_push (new_binfo);
1629       BINFO_VIRTUAL_P (new_binfo) = 1;
1630       BINFO_INHERITANCE_CHAIN (new_binfo) = TYPE_BINFO (t);
1631     }
1632
1633   return new_binfo;
1634 }
1635 \f
1636 /* Hashing of lists so that we don't make duplicates.
1637    The entry point is `list_hash_canon'.  */
1638
1639 struct list_proxy
1640 {
1641   tree purpose;
1642   tree value;
1643   tree chain;
1644 };
1645
1646 struct list_hasher : ggc_hasher<tree>
1647 {
1648   typedef list_proxy *compare_type;
1649
1650   static hashval_t hash (tree);
1651   static bool equal (tree, list_proxy *);
1652 };
1653
1654 /* Now here is the hash table.  When recording a list, it is added
1655    to the slot whose index is the hash code mod the table size.
1656    Note that the hash table is used for several kinds of lists.
1657    While all these live in the same table, they are completely independent,
1658    and the hash code is computed differently for each of these.  */
1659
1660 static GTY (()) hash_table<list_hasher> *list_hash_table;
1661
1662 /* Compare ENTRY (an entry in the hash table) with DATA (a list_proxy
1663    for a node we are thinking about adding).  */
1664
1665 bool
1666 list_hasher::equal (tree t, list_proxy *proxy)
1667 {
1668   return (TREE_VALUE (t) == proxy->value
1669           && TREE_PURPOSE (t) == proxy->purpose
1670           && TREE_CHAIN (t) == proxy->chain);
1671 }
1672
1673 /* Compute a hash code for a list (chain of TREE_LIST nodes
1674    with goodies in the TREE_PURPOSE, TREE_VALUE, and bits of the
1675    TREE_COMMON slots), by adding the hash codes of the individual entries.  */
1676
1677 static hashval_t
1678 list_hash_pieces (tree purpose, tree value, tree chain)
1679 {
1680   hashval_t hashcode = 0;
1681
1682   if (chain)
1683     hashcode += TREE_HASH (chain);
1684
1685   if (value)
1686     hashcode += TREE_HASH (value);
1687   else
1688     hashcode += 1007;
1689   if (purpose)
1690     hashcode += TREE_HASH (purpose);
1691   else
1692     hashcode += 1009;
1693   return hashcode;
1694 }
1695
1696 /* Hash an already existing TREE_LIST.  */
1697
1698 hashval_t
1699 list_hasher::hash (tree t)
1700 {
1701   return list_hash_pieces (TREE_PURPOSE (t),
1702                            TREE_VALUE (t),
1703                            TREE_CHAIN (t));
1704 }
1705
1706 /* Given list components PURPOSE, VALUE, AND CHAIN, return the canonical
1707    object for an identical list if one already exists.  Otherwise, build a
1708    new one, and record it as the canonical object.  */
1709
1710 tree
1711 hash_tree_cons (tree purpose, tree value, tree chain)
1712 {
1713   int hashcode = 0;
1714   tree *slot;
1715   struct list_proxy proxy;
1716
1717   /* Hash the list node.  */
1718   hashcode = list_hash_pieces (purpose, value, chain);
1719   /* Create a proxy for the TREE_LIST we would like to create.  We
1720      don't actually create it so as to avoid creating garbage.  */
1721   proxy.purpose = purpose;
1722   proxy.value = value;
1723   proxy.chain = chain;
1724   /* See if it is already in the table.  */
1725   slot = list_hash_table->find_slot_with_hash (&proxy, hashcode, INSERT);
1726   /* If not, create a new node.  */
1727   if (!*slot)
1728     *slot = tree_cons (purpose, value, chain);
1729   return (tree) *slot;
1730 }
1731
1732 /* Constructor for hashed lists.  */
1733
1734 tree
1735 hash_tree_chain (tree value, tree chain)
1736 {
1737   return hash_tree_cons (NULL_TREE, value, chain);
1738 }
1739 \f
1740 void
1741 debug_binfo (tree elem)
1742 {
1743   HOST_WIDE_INT n;
1744   tree virtuals;
1745
1746   fprintf (stderr, "type \"%s\", offset = " HOST_WIDE_INT_PRINT_DEC
1747            "\nvtable type:\n",
1748            TYPE_NAME_STRING (BINFO_TYPE (elem)),
1749            TREE_INT_CST_LOW (BINFO_OFFSET (elem)));
1750   debug_tree (BINFO_TYPE (elem));
1751   if (BINFO_VTABLE (elem))
1752     fprintf (stderr, "vtable decl \"%s\"\n",
1753              IDENTIFIER_POINTER (DECL_NAME (get_vtbl_decl_for_binfo (elem))));
1754   else
1755     fprintf (stderr, "no vtable decl yet\n");
1756   fprintf (stderr, "virtuals:\n");
1757   virtuals = BINFO_VIRTUALS (elem);
1758   n = 0;
1759
1760   while (virtuals)
1761     {
1762       tree fndecl = TREE_VALUE (virtuals);
1763       fprintf (stderr, "%s [%ld =? %ld]\n",
1764                IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (fndecl)),
1765                (long) n, (long) TREE_INT_CST_LOW (DECL_VINDEX (fndecl)));
1766       ++n;
1767       virtuals = TREE_CHAIN (virtuals);
1768     }
1769 }
1770
1771 /* Build a representation for the qualified name SCOPE::NAME.  TYPE is
1772    the type of the result expression, if known, or NULL_TREE if the
1773    resulting expression is type-dependent.  If TEMPLATE_P is true,
1774    NAME is known to be a template because the user explicitly used the
1775    "template" keyword after the "::".
1776
1777    All SCOPE_REFs should be built by use of this function.  */
1778
1779 tree
1780 build_qualified_name (tree type, tree scope, tree name, bool template_p)
1781 {
1782   tree t;
1783   if (type == error_mark_node
1784       || scope == error_mark_node
1785       || name == error_mark_node)
1786     return error_mark_node;
1787   t = build2 (SCOPE_REF, type, scope, name);
1788   QUALIFIED_NAME_IS_TEMPLATE (t) = template_p;
1789   PTRMEM_OK_P (t) = true;
1790   if (type)
1791     t = convert_from_reference (t);
1792   return t;
1793 }
1794
1795 /* Like check_qualified_type, but also check ref-qualifier and exception
1796    specification.  */
1797
1798 static bool
1799 cp_check_qualified_type (const_tree cand, const_tree base, int type_quals,
1800                          cp_ref_qualifier rqual, tree raises)
1801 {
1802   return (check_qualified_type (cand, base, type_quals)
1803           && comp_except_specs (raises, TYPE_RAISES_EXCEPTIONS (cand),
1804                                 ce_exact)
1805           && type_memfn_rqual (cand) == rqual);
1806 }
1807
1808 /* Build the FUNCTION_TYPE or METHOD_TYPE with the ref-qualifier RQUAL.  */
1809
1810 tree
1811 build_ref_qualified_type (tree type, cp_ref_qualifier rqual)
1812 {
1813   tree t;
1814
1815   if (rqual == type_memfn_rqual (type))
1816     return type;
1817
1818   int type_quals = TYPE_QUALS (type);
1819   tree raises = TYPE_RAISES_EXCEPTIONS (type);
1820   for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
1821     if (cp_check_qualified_type (t, type, type_quals, rqual, raises))
1822       return t;
1823
1824   t = build_variant_type_copy (type);
1825   switch (rqual)
1826     {
1827     case REF_QUAL_RVALUE:
1828       FUNCTION_RVALUE_QUALIFIED (t) = 1;
1829       FUNCTION_REF_QUALIFIED (t) = 1;
1830       break;
1831     case REF_QUAL_LVALUE:
1832       FUNCTION_RVALUE_QUALIFIED (t) = 0;
1833       FUNCTION_REF_QUALIFIED (t) = 1;
1834       break;
1835     default:
1836       FUNCTION_REF_QUALIFIED (t) = 0;
1837       break;
1838     }
1839
1840   if (TYPE_STRUCTURAL_EQUALITY_P (type))
1841     /* Propagate structural equality. */
1842     SET_TYPE_STRUCTURAL_EQUALITY (t);
1843   else if (TYPE_CANONICAL (type) != type)
1844     /* Build the underlying canonical type, since it is different
1845        from TYPE. */
1846     TYPE_CANONICAL (t) = build_ref_qualified_type (TYPE_CANONICAL (type),
1847                                                    rqual);
1848   else
1849     /* T is its own canonical type. */
1850     TYPE_CANONICAL (t) = t;
1851
1852   return t;
1853 }
1854
1855 /* Returns nonzero if X is an expression for a (possibly overloaded)
1856    function.  If "f" is a function or function template, "f", "c->f",
1857    "c.f", "C::f", and "f<int>" will all be considered possibly
1858    overloaded functions.  Returns 2 if the function is actually
1859    overloaded, i.e., if it is impossible to know the type of the
1860    function without performing overload resolution.  */
1861
1862 int
1863 is_overloaded_fn (tree x)
1864 {
1865   /* A baselink is also considered an overloaded function.  */
1866   if (TREE_CODE (x) == OFFSET_REF
1867       || TREE_CODE (x) == COMPONENT_REF)
1868     x = TREE_OPERAND (x, 1);
1869   if (BASELINK_P (x))
1870     x = BASELINK_FUNCTIONS (x);
1871   if (TREE_CODE (x) == TEMPLATE_ID_EXPR)
1872     x = TREE_OPERAND (x, 0);
1873   if (DECL_FUNCTION_TEMPLATE_P (OVL_CURRENT (x))
1874       || (TREE_CODE (x) == OVERLOAD && OVL_CHAIN (x)))
1875     return 2;
1876   return  (TREE_CODE (x) == FUNCTION_DECL
1877            || TREE_CODE (x) == OVERLOAD);
1878 }
1879
1880 /* X is the CALL_EXPR_FN of a CALL_EXPR.  If X represents a dependent name
1881    (14.6.2), return the IDENTIFIER_NODE for that name.  Otherwise, return
1882    NULL_TREE.  */
1883
1884 tree
1885 dependent_name (tree x)
1886 {
1887   if (identifier_p (x))
1888     return x;
1889   if (TREE_CODE (x) != COMPONENT_REF
1890       && TREE_CODE (x) != OFFSET_REF
1891       && TREE_CODE (x) != BASELINK
1892       && is_overloaded_fn (x))
1893     return DECL_NAME (get_first_fn (x));
1894   return NULL_TREE;
1895 }
1896
1897 /* Returns true iff X is an expression for an overloaded function
1898    whose type cannot be known without performing overload
1899    resolution.  */
1900
1901 bool
1902 really_overloaded_fn (tree x)
1903 {
1904   return is_overloaded_fn (x) == 2;
1905 }
1906
1907 tree
1908 get_fns (tree from)
1909 {
1910   gcc_assert (is_overloaded_fn (from));
1911   /* A baselink is also considered an overloaded function.  */
1912   if (TREE_CODE (from) == OFFSET_REF
1913       || TREE_CODE (from) == COMPONENT_REF)
1914     from = TREE_OPERAND (from, 1);
1915   if (BASELINK_P (from))
1916     from = BASELINK_FUNCTIONS (from);
1917   if (TREE_CODE (from) == TEMPLATE_ID_EXPR)
1918     from = TREE_OPERAND (from, 0);
1919   return from;
1920 }
1921
1922 tree
1923 get_first_fn (tree from)
1924 {
1925   return OVL_CURRENT (get_fns (from));
1926 }
1927
1928 /* Return a new OVL node, concatenating it with the old one.  */
1929
1930 tree
1931 ovl_cons (tree decl, tree chain)
1932 {
1933   tree result = make_node (OVERLOAD);
1934   TREE_TYPE (result) = unknown_type_node;
1935   OVL_FUNCTION (result) = decl;
1936   TREE_CHAIN (result) = chain;
1937
1938   return result;
1939 }
1940
1941 /* Build a new overloaded function. If this is the first one,
1942    just return it; otherwise, ovl_cons the _DECLs */
1943
1944 tree
1945 build_overload (tree decl, tree chain)
1946 {
1947   if (! chain && TREE_CODE (decl) != TEMPLATE_DECL)
1948     return decl;
1949   return ovl_cons (decl, chain);
1950 }
1951
1952 /* Return the scope where the overloaded functions OVL were found.  */
1953
1954 tree
1955 ovl_scope (tree ovl)
1956 {
1957   if (TREE_CODE (ovl) == OFFSET_REF
1958       || TREE_CODE (ovl) == COMPONENT_REF)
1959     ovl = TREE_OPERAND (ovl, 1);
1960   if (TREE_CODE (ovl) == BASELINK)
1961     return BINFO_TYPE (BASELINK_BINFO (ovl));
1962   if (TREE_CODE (ovl) == TEMPLATE_ID_EXPR)
1963     ovl = TREE_OPERAND (ovl, 0);
1964   /* Skip using-declarations.  */
1965   while (TREE_CODE (ovl) == OVERLOAD && OVL_USED (ovl) && OVL_CHAIN (ovl))
1966     ovl = OVL_CHAIN (ovl);
1967   return CP_DECL_CONTEXT (OVL_CURRENT (ovl));
1968 }
1969
1970 /* Return TRUE if FN is a non-static member function, FALSE otherwise.
1971    This function looks into BASELINK and OVERLOAD nodes.  */
1972
1973 bool
1974 non_static_member_function_p (tree fn)
1975 {
1976   if (fn == NULL_TREE)
1977     return false;
1978
1979   if (is_overloaded_fn (fn))
1980     fn = get_first_fn (fn);
1981
1982   return (DECL_P (fn)
1983           && DECL_NONSTATIC_MEMBER_FUNCTION_P (fn));
1984 }
1985
1986 \f
1987 #define PRINT_RING_SIZE 4
1988
1989 static const char *
1990 cxx_printable_name_internal (tree decl, int v, bool translate)
1991 {
1992   static unsigned int uid_ring[PRINT_RING_SIZE];
1993   static char *print_ring[PRINT_RING_SIZE];
1994   static bool trans_ring[PRINT_RING_SIZE];
1995   static int ring_counter;
1996   int i;
1997
1998   /* Only cache functions.  */
1999   if (v < 2
2000       || TREE_CODE (decl) != FUNCTION_DECL
2001       || DECL_LANG_SPECIFIC (decl) == 0)
2002     return lang_decl_name (decl, v, translate);
2003
2004   /* See if this print name is lying around.  */
2005   for (i = 0; i < PRINT_RING_SIZE; i++)
2006     if (uid_ring[i] == DECL_UID (decl) && translate == trans_ring[i])
2007       /* yes, so return it.  */
2008       return print_ring[i];
2009
2010   if (++ring_counter == PRINT_RING_SIZE)
2011     ring_counter = 0;
2012
2013   if (current_function_decl != NULL_TREE)
2014     {
2015       /* There may be both translated and untranslated versions of the
2016          name cached.  */
2017       for (i = 0; i < 2; i++)
2018         {
2019           if (uid_ring[ring_counter] == DECL_UID (current_function_decl))
2020             ring_counter += 1;
2021           if (ring_counter == PRINT_RING_SIZE)
2022             ring_counter = 0;
2023         }
2024       gcc_assert (uid_ring[ring_counter] != DECL_UID (current_function_decl));
2025     }
2026
2027   free (print_ring[ring_counter]);
2028
2029   print_ring[ring_counter] = xstrdup (lang_decl_name (decl, v, translate));
2030   uid_ring[ring_counter] = DECL_UID (decl);
2031   trans_ring[ring_counter] = translate;
2032   return print_ring[ring_counter];
2033 }
2034
2035 const char *
2036 cxx_printable_name (tree decl, int v)
2037 {
2038   return cxx_printable_name_internal (decl, v, false);
2039 }
2040
2041 const char *
2042 cxx_printable_name_translate (tree decl, int v)
2043 {
2044   return cxx_printable_name_internal (decl, v, true);
2045 }
2046 \f
2047 /* Build the FUNCTION_TYPE or METHOD_TYPE which may throw exceptions
2048    listed in RAISES.  */
2049
2050 tree
2051 build_exception_variant (tree type, tree raises)
2052 {
2053   tree v;
2054   int type_quals;
2055
2056   if (comp_except_specs (raises, TYPE_RAISES_EXCEPTIONS (type), ce_exact))
2057     return type;
2058
2059   type_quals = TYPE_QUALS (type);
2060   cp_ref_qualifier rqual = type_memfn_rqual (type);
2061   for (v = TYPE_MAIN_VARIANT (type); v; v = TYPE_NEXT_VARIANT (v))
2062     if (cp_check_qualified_type (v, type, type_quals, rqual, raises))
2063       return v;
2064
2065   /* Need to build a new variant.  */
2066   v = build_variant_type_copy (type);
2067   TYPE_RAISES_EXCEPTIONS (v) = raises;
2068   return v;
2069 }
2070
2071 /* Given a TEMPLATE_TEMPLATE_PARM node T, create a new
2072    BOUND_TEMPLATE_TEMPLATE_PARM bound with NEWARGS as its template
2073    arguments.  */
2074
2075 tree
2076 bind_template_template_parm (tree t, tree newargs)
2077 {
2078   tree decl = TYPE_NAME (t);
2079   tree t2;
2080
2081   t2 = cxx_make_type (BOUND_TEMPLATE_TEMPLATE_PARM);
2082   decl = build_decl (input_location,
2083                      TYPE_DECL, DECL_NAME (decl), NULL_TREE);
2084
2085   /* These nodes have to be created to reflect new TYPE_DECL and template
2086      arguments.  */
2087   TEMPLATE_TYPE_PARM_INDEX (t2) = copy_node (TEMPLATE_TYPE_PARM_INDEX (t));
2088   TEMPLATE_PARM_DECL (TEMPLATE_TYPE_PARM_INDEX (t2)) = decl;
2089   TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (t2)
2090     = build_template_info (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t), newargs);
2091
2092   TREE_TYPE (decl) = t2;
2093   TYPE_NAME (t2) = decl;
2094   TYPE_STUB_DECL (t2) = decl;
2095   TYPE_SIZE (t2) = 0;
2096   SET_TYPE_STRUCTURAL_EQUALITY (t2);
2097
2098   return t2;
2099 }
2100
2101 /* Called from count_trees via walk_tree.  */
2102
2103 static tree
2104 count_trees_r (tree *tp, int *walk_subtrees, void *data)
2105 {
2106   ++*((int *) data);
2107
2108   if (TYPE_P (*tp))
2109     *walk_subtrees = 0;
2110
2111   return NULL_TREE;
2112 }
2113
2114 /* Debugging function for measuring the rough complexity of a tree
2115    representation.  */
2116
2117 int
2118 count_trees (tree t)
2119 {
2120   int n_trees = 0;
2121   cp_walk_tree_without_duplicates (&t, count_trees_r, &n_trees);
2122   return n_trees;
2123 }
2124
2125 /* Called from verify_stmt_tree via walk_tree.  */
2126
2127 static tree
2128 verify_stmt_tree_r (tree* tp, int * /*walk_subtrees*/, void* data)
2129 {
2130   tree t = *tp;
2131   hash_table<pointer_hash <tree_node> > *statements
2132       = static_cast <hash_table<pointer_hash <tree_node> > *> (data);
2133   tree_node **slot;
2134
2135   if (!STATEMENT_CODE_P (TREE_CODE (t)))
2136     return NULL_TREE;
2137
2138   /* If this statement is already present in the hash table, then
2139      there is a circularity in the statement tree.  */
2140   gcc_assert (!statements->find (t));
2141
2142   slot = statements->find_slot (t, INSERT);
2143   *slot = t;
2144
2145   return NULL_TREE;
2146 }
2147
2148 /* Debugging function to check that the statement T has not been
2149    corrupted.  For now, this function simply checks that T contains no
2150    circularities.  */
2151
2152 void
2153 verify_stmt_tree (tree t)
2154 {
2155   hash_table<pointer_hash <tree_node> > statements (37);
2156   cp_walk_tree (&t, verify_stmt_tree_r, &statements, NULL);
2157 }
2158
2159 /* Check if the type T depends on a type with no linkage and if so, return
2160    it.  If RELAXED_P then do not consider a class type declared within
2161    a vague-linkage function to have no linkage.  */
2162
2163 tree
2164 no_linkage_check (tree t, bool relaxed_p)
2165 {
2166   tree r;
2167
2168   /* There's no point in checking linkage on template functions; we
2169      can't know their complete types.  */
2170   if (processing_template_decl)
2171     return NULL_TREE;
2172
2173   switch (TREE_CODE (t))
2174     {
2175     case RECORD_TYPE:
2176       if (TYPE_PTRMEMFUNC_P (t))
2177         goto ptrmem;
2178       /* Lambda types that don't have mangling scope have no linkage.  We
2179          check CLASSTYPE_LAMBDA_EXPR for error_mark_node because
2180          when we get here from pushtag none of the lambda information is
2181          set up yet, so we want to assume that the lambda has linkage and
2182          fix it up later if not.  */
2183       if (CLASSTYPE_LAMBDA_EXPR (t)
2184           && CLASSTYPE_LAMBDA_EXPR (t) != error_mark_node
2185           && LAMBDA_TYPE_EXTRA_SCOPE (t) == NULL_TREE)
2186         return t;
2187       /* Fall through.  */
2188     case UNION_TYPE:
2189       if (!CLASS_TYPE_P (t))
2190         return NULL_TREE;
2191       /* Fall through.  */
2192     case ENUMERAL_TYPE:
2193       /* Only treat anonymous types as having no linkage if they're at
2194          namespace scope.  This is core issue 966.  */
2195       if (TYPE_ANONYMOUS_P (t) && TYPE_NAMESPACE_SCOPE_P (t))
2196         return t;
2197
2198       for (r = CP_TYPE_CONTEXT (t); ; )
2199         {
2200           /* If we're a nested type of a !TREE_PUBLIC class, we might not
2201              have linkage, or we might just be in an anonymous namespace.
2202              If we're in a TREE_PUBLIC class, we have linkage.  */
2203           if (TYPE_P (r) && !TREE_PUBLIC (TYPE_NAME (r)))
2204             return no_linkage_check (TYPE_CONTEXT (t), relaxed_p);
2205           else if (TREE_CODE (r) == FUNCTION_DECL)
2206             {
2207               if (!relaxed_p || !vague_linkage_p (r))
2208                 return t;
2209               else
2210                 r = CP_DECL_CONTEXT (r);
2211             }
2212           else
2213             break;
2214         }
2215
2216       return NULL_TREE;
2217
2218     case ARRAY_TYPE:
2219     case POINTER_TYPE:
2220     case REFERENCE_TYPE:
2221     case VECTOR_TYPE:
2222       return no_linkage_check (TREE_TYPE (t), relaxed_p);
2223
2224     case OFFSET_TYPE:
2225     ptrmem:
2226       r = no_linkage_check (TYPE_PTRMEM_POINTED_TO_TYPE (t),
2227                             relaxed_p);
2228       if (r)
2229         return r;
2230       return no_linkage_check (TYPE_PTRMEM_CLASS_TYPE (t), relaxed_p);
2231
2232     case METHOD_TYPE:
2233       r = no_linkage_check (TYPE_METHOD_BASETYPE (t), relaxed_p);
2234       if (r)
2235         return r;
2236       /* Fall through.  */
2237     case FUNCTION_TYPE:
2238       {
2239         tree parm;
2240         for (parm = TYPE_ARG_TYPES (t);
2241              parm && parm != void_list_node;
2242              parm = TREE_CHAIN (parm))
2243           {
2244             r = no_linkage_check (TREE_VALUE (parm), relaxed_p);
2245             if (r)
2246               return r;
2247           }
2248         return no_linkage_check (TREE_TYPE (t), relaxed_p);
2249       }
2250
2251     default:
2252       return NULL_TREE;
2253     }
2254 }
2255
2256 extern int depth_reached;
2257
2258 void
2259 cxx_print_statistics (void)
2260 {
2261   print_search_statistics ();
2262   print_class_statistics ();
2263   print_template_statistics ();
2264   if (GATHER_STATISTICS)
2265     fprintf (stderr, "maximum template instantiation depth reached: %d\n",
2266              depth_reached);
2267 }
2268
2269 /* Return, as an INTEGER_CST node, the number of elements for TYPE
2270    (which is an ARRAY_TYPE).  This counts only elements of the top
2271    array.  */
2272
2273 tree
2274 array_type_nelts_top (tree type)
2275 {
2276   return fold_build2_loc (input_location,
2277                       PLUS_EXPR, sizetype,
2278                       array_type_nelts (type),
2279                       size_one_node);
2280 }
2281
2282 /* Return, as an INTEGER_CST node, the number of elements for TYPE
2283    (which is an ARRAY_TYPE).  This one is a recursive count of all
2284    ARRAY_TYPEs that are clumped together.  */
2285
2286 tree
2287 array_type_nelts_total (tree type)
2288 {
2289   tree sz = array_type_nelts_top (type);
2290   type = TREE_TYPE (type);
2291   while (TREE_CODE (type) == ARRAY_TYPE)
2292     {
2293       tree n = array_type_nelts_top (type);
2294       sz = fold_build2_loc (input_location,
2295                         MULT_EXPR, sizetype, sz, n);
2296       type = TREE_TYPE (type);
2297     }
2298   return sz;
2299 }
2300
2301 /* Called from break_out_target_exprs via mapcar.  */
2302
2303 static tree
2304 bot_manip (tree* tp, int* walk_subtrees, void* data)
2305 {
2306   splay_tree target_remap = ((splay_tree) data);
2307   tree t = *tp;
2308
2309   if (!TYPE_P (t) && TREE_CONSTANT (t) && !TREE_SIDE_EFFECTS (t))
2310     {
2311       /* There can't be any TARGET_EXPRs or their slot variables below this
2312          point.  But we must make a copy, in case subsequent processing
2313          alters any part of it.  For example, during gimplification a cast
2314          of the form (T) &X::f (where "f" is a member function) will lead
2315          to replacing the PTRMEM_CST for &X::f with a VAR_DECL.  */
2316       *walk_subtrees = 0;
2317       *tp = unshare_expr (t);
2318       return NULL_TREE;
2319     }
2320   if (TREE_CODE (t) == TARGET_EXPR)
2321     {
2322       tree u;
2323
2324       if (TREE_CODE (TREE_OPERAND (t, 1)) == AGGR_INIT_EXPR)
2325         {
2326           u = build_cplus_new (TREE_TYPE (t), TREE_OPERAND (t, 1),
2327                                tf_warning_or_error);
2328           if (AGGR_INIT_ZERO_FIRST (TREE_OPERAND (t, 1)))
2329             AGGR_INIT_ZERO_FIRST (TREE_OPERAND (u, 1)) = true;
2330         }
2331       else
2332         u = build_target_expr_with_type (TREE_OPERAND (t, 1), TREE_TYPE (t),
2333                                          tf_warning_or_error);
2334
2335       TARGET_EXPR_IMPLICIT_P (u) = TARGET_EXPR_IMPLICIT_P (t);
2336       TARGET_EXPR_LIST_INIT_P (u) = TARGET_EXPR_LIST_INIT_P (t);
2337       TARGET_EXPR_DIRECT_INIT_P (u) = TARGET_EXPR_DIRECT_INIT_P (t);
2338
2339       /* Map the old variable to the new one.  */
2340       splay_tree_insert (target_remap,
2341                          (splay_tree_key) TREE_OPERAND (t, 0),
2342                          (splay_tree_value) TREE_OPERAND (u, 0));
2343
2344       TREE_OPERAND (u, 1) = break_out_target_exprs (TREE_OPERAND (u, 1));
2345
2346       /* Replace the old expression with the new version.  */
2347       *tp = u;
2348       /* We don't have to go below this point; the recursive call to
2349          break_out_target_exprs will have handled anything below this
2350          point.  */
2351       *walk_subtrees = 0;
2352       return NULL_TREE;
2353     }
2354
2355   /* Make a copy of this node.  */
2356   t = copy_tree_r (tp, walk_subtrees, NULL);
2357   if (TREE_CODE (*tp) == CALL_EXPR)
2358     {
2359       set_flags_from_callee (*tp);
2360
2361       /* builtin_LINE and builtin_FILE get the location where the default
2362          argument is expanded, not where the call was written.  */
2363       tree callee = get_callee_fndecl (*tp);
2364       if (callee && DECL_BUILT_IN (callee))
2365         switch (DECL_FUNCTION_CODE (callee))
2366           {
2367           case BUILT_IN_FILE:
2368           case BUILT_IN_LINE:
2369             SET_EXPR_LOCATION (*tp, input_location);
2370           default:
2371             break;
2372           }
2373     }
2374   return t;
2375 }
2376
2377 /* Replace all remapped VAR_DECLs in T with their new equivalents.
2378    DATA is really a splay-tree mapping old variables to new
2379    variables.  */
2380
2381 static tree
2382 bot_replace (tree* t, int* /*walk_subtrees*/, void* data)
2383 {
2384   splay_tree target_remap = ((splay_tree) data);
2385
2386   if (VAR_P (*t))
2387     {
2388       splay_tree_node n = splay_tree_lookup (target_remap,
2389                                              (splay_tree_key) *t);
2390       if (n)
2391         *t = (tree) n->value;
2392     }
2393   else if (TREE_CODE (*t) == PARM_DECL
2394            && DECL_NAME (*t) == this_identifier
2395            && !DECL_CONTEXT (*t))
2396     {
2397       /* In an NSDMI we need to replace the 'this' parameter we used for
2398          parsing with the real one for this function.  */
2399       *t = current_class_ptr;
2400     }
2401   else if (TREE_CODE (*t) == CONVERT_EXPR
2402            && CONVERT_EXPR_VBASE_PATH (*t))
2403     {
2404       /* In an NSDMI build_base_path defers building conversions to virtual
2405          bases, and we handle it here.  */
2406       tree basetype = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (*t)));
2407       vec<tree, va_gc> *vbases = CLASSTYPE_VBASECLASSES (current_class_type);
2408       int i; tree binfo;
2409       FOR_EACH_VEC_SAFE_ELT (vbases, i, binfo)
2410         if (BINFO_TYPE (binfo) == basetype)
2411           break;
2412       *t = build_base_path (PLUS_EXPR, TREE_OPERAND (*t, 0), binfo, true,
2413                             tf_warning_or_error);
2414     }
2415
2416   return NULL_TREE;
2417 }
2418
2419 /* When we parse a default argument expression, we may create
2420    temporary variables via TARGET_EXPRs.  When we actually use the
2421    default-argument expression, we make a copy of the expression
2422    and replace the temporaries with appropriate local versions.  */
2423
2424 tree
2425 break_out_target_exprs (tree t)
2426 {
2427   static int target_remap_count;
2428   static splay_tree target_remap;
2429
2430   if (!target_remap_count++)
2431     target_remap = splay_tree_new (splay_tree_compare_pointers,
2432                                    /*splay_tree_delete_key_fn=*/NULL,
2433                                    /*splay_tree_delete_value_fn=*/NULL);
2434   cp_walk_tree (&t, bot_manip, target_remap, NULL);
2435   cp_walk_tree (&t, bot_replace, target_remap, NULL);
2436
2437   if (!--target_remap_count)
2438     {
2439       splay_tree_delete (target_remap);
2440       target_remap = NULL;
2441     }
2442
2443   return t;
2444 }
2445
2446 /* Build an expression for the subobject of OBJ at CONSTRUCTOR index INDEX,
2447    which we expect to have type TYPE.  */
2448
2449 tree
2450 build_ctor_subob_ref (tree index, tree type, tree obj)
2451 {
2452   if (index == NULL_TREE)
2453     /* Can't refer to a particular member of a vector.  */
2454     obj = NULL_TREE;
2455   else if (TREE_CODE (index) == INTEGER_CST)
2456     obj = cp_build_array_ref (input_location, obj, index, tf_none);
2457   else
2458     obj = build_class_member_access_expr (obj, index, NULL_TREE,
2459                                           /*reference*/false, tf_none);
2460   if (obj)
2461     gcc_assert (same_type_ignoring_top_level_qualifiers_p (type,
2462                                                            TREE_TYPE (obj)));
2463   return obj;
2464 }
2465
2466 /* Like substitute_placeholder_in_expr, but handle C++ tree codes and
2467    build up subexpressions as we go deeper.  */
2468
2469 struct replace_placeholders_t
2470 {
2471   tree obj;
2472   hash_set<tree> *pset;
2473 };
2474
2475 static tree
2476 replace_placeholders_r (tree* t, int* walk_subtrees, void* data_)
2477 {
2478   tree obj = static_cast<tree>(data_);
2479
2480   if (TREE_CONSTANT (*t))
2481     {
2482       *walk_subtrees = false;
2483       return NULL_TREE;
2484     }
2485
2486   switch (TREE_CODE (*t))
2487     {
2488     case PLACEHOLDER_EXPR:
2489       gcc_assert (same_type_ignoring_top_level_qualifiers_p
2490                   (TREE_TYPE (*t), TREE_TYPE (obj)));
2491       *t = obj;
2492       *walk_subtrees = false;
2493       break;
2494
2495     case TARGET_EXPR:
2496       /* Don't mess with placeholders in an unrelated object.  */
2497       *walk_subtrees = false;
2498       break;
2499
2500     case CONSTRUCTOR:
2501       {
2502         constructor_elt *ce;
2503         vec<constructor_elt,va_gc> *v = CONSTRUCTOR_ELTS (*t);
2504         for (unsigned i = 0; vec_safe_iterate (v, i, &ce); ++i)
2505           {
2506             tree *valp = &ce->value;
2507             tree type = TREE_TYPE (*valp);
2508             tree subob = obj;
2509
2510             if (TREE_CODE (*valp) == CONSTRUCTOR
2511                 && AGGREGATE_TYPE_P (type))
2512               {
2513                 subob = build_ctor_subob_ref (ce->index, type, obj);
2514                 if (TREE_CODE (*valp) == TARGET_EXPR)
2515                   valp = &TARGET_EXPR_INITIAL (*valp);
2516               }
2517
2518             cp_walk_tree (valp, replace_placeholders_r,
2519                           subob, NULL);
2520           }
2521         *walk_subtrees = false;
2522         break;
2523       }
2524
2525     default:
2526       break;
2527     }
2528
2529   return NULL_TREE;
2530 }
2531
2532 tree
2533 replace_placeholders (tree exp, tree obj)
2534 {
2535   hash_set<tree> pset;
2536   tree *tp = &exp;
2537   if (TREE_CODE (exp) == TARGET_EXPR)
2538     tp = &TARGET_EXPR_INITIAL (exp);
2539   cp_walk_tree (tp, replace_placeholders_r, obj, NULL);
2540   return exp;
2541 }
2542
2543 /* Similar to `build_nt', but for template definitions of dependent
2544    expressions  */
2545
2546 tree
2547 build_min_nt_loc (location_t loc, enum tree_code code, ...)
2548 {
2549   tree t;
2550   int length;
2551   int i;
2552   va_list p;
2553
2554   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
2555
2556   va_start (p, code);
2557
2558   t = make_node (code);
2559   SET_EXPR_LOCATION (t, loc);
2560   length = TREE_CODE_LENGTH (code);
2561
2562   for (i = 0; i < length; i++)
2563     {
2564       tree x = va_arg (p, tree);
2565       TREE_OPERAND (t, i) = x;
2566     }
2567
2568   va_end (p);
2569   return t;
2570 }
2571
2572
2573 /* Similar to `build', but for template definitions.  */
2574
2575 tree
2576 build_min (enum tree_code code, tree tt, ...)
2577 {
2578   tree t;
2579   int length;
2580   int i;
2581   va_list p;
2582
2583   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
2584
2585   va_start (p, tt);
2586
2587   t = make_node (code);
2588   length = TREE_CODE_LENGTH (code);
2589   TREE_TYPE (t) = tt;
2590
2591   for (i = 0; i < length; i++)
2592     {
2593       tree x = va_arg (p, tree);
2594       TREE_OPERAND (t, i) = x;
2595       if (x && !TYPE_P (x) && TREE_SIDE_EFFECTS (x))
2596         TREE_SIDE_EFFECTS (t) = 1;
2597     }
2598
2599   va_end (p);
2600   return t;
2601 }
2602
2603 /* Similar to `build', but for template definitions of non-dependent
2604    expressions. NON_DEP is the non-dependent expression that has been
2605    built.  */
2606
2607 tree
2608 build_min_non_dep (enum tree_code code, tree non_dep, ...)
2609 {
2610   tree t;
2611   int length;
2612   int i;
2613   va_list p;
2614
2615   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
2616
2617   va_start (p, non_dep);
2618
2619   if (REFERENCE_REF_P (non_dep))
2620     non_dep = TREE_OPERAND (non_dep, 0);
2621
2622   t = make_node (code);
2623   length = TREE_CODE_LENGTH (code);
2624   TREE_TYPE (t) = TREE_TYPE (non_dep);
2625   TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (non_dep);
2626
2627   for (i = 0; i < length; i++)
2628     {
2629       tree x = va_arg (p, tree);
2630       TREE_OPERAND (t, i) = x;
2631     }
2632
2633   if (code == COMPOUND_EXPR && TREE_CODE (non_dep) != COMPOUND_EXPR)
2634     /* This should not be considered a COMPOUND_EXPR, because it
2635        resolves to an overload.  */
2636     COMPOUND_EXPR_OVERLOADED (t) = 1;
2637
2638   va_end (p);
2639   return convert_from_reference (t);
2640 }
2641
2642 /* Similar to `build_nt_call_vec', but for template definitions of
2643    non-dependent expressions. NON_DEP is the non-dependent expression
2644    that has been built.  */
2645
2646 tree
2647 build_min_non_dep_call_vec (tree non_dep, tree fn, vec<tree, va_gc> *argvec)
2648 {
2649   tree t = build_nt_call_vec (fn, argvec);
2650   if (REFERENCE_REF_P (non_dep))
2651     non_dep = TREE_OPERAND (non_dep, 0);
2652   TREE_TYPE (t) = TREE_TYPE (non_dep);
2653   TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (non_dep);
2654   return convert_from_reference (t);
2655 }
2656
2657 tree
2658 get_type_decl (tree t)
2659 {
2660   if (TREE_CODE (t) == TYPE_DECL)
2661     return t;
2662   if (TYPE_P (t))
2663     return TYPE_STUB_DECL (t);
2664   gcc_assert (t == error_mark_node);
2665   return t;
2666 }
2667
2668 /* Returns the namespace that contains DECL, whether directly or
2669    indirectly.  */
2670
2671 tree
2672 decl_namespace_context (tree decl)
2673 {
2674   while (1)
2675     {
2676       if (TREE_CODE (decl) == NAMESPACE_DECL)
2677         return decl;
2678       else if (TYPE_P (decl))
2679         decl = CP_DECL_CONTEXT (TYPE_MAIN_DECL (decl));
2680       else
2681         decl = CP_DECL_CONTEXT (decl);
2682     }
2683 }
2684
2685 /* Returns true if decl is within an anonymous namespace, however deeply
2686    nested, or false otherwise.  */
2687
2688 bool
2689 decl_anon_ns_mem_p (const_tree decl)
2690 {
2691   while (1)
2692     {
2693       if (decl == NULL_TREE || decl == error_mark_node)
2694         return false;
2695       if (TREE_CODE (decl) == NAMESPACE_DECL
2696           && DECL_NAME (decl) == NULL_TREE)
2697         return true;
2698       /* Classes and namespaces inside anonymous namespaces have
2699          TREE_PUBLIC == 0, so we can shortcut the search.  */
2700       else if (TYPE_P (decl))
2701         return (TREE_PUBLIC (TYPE_MAIN_DECL (decl)) == 0);
2702       else if (TREE_CODE (decl) == NAMESPACE_DECL)
2703         return (TREE_PUBLIC (decl) == 0);
2704       else
2705         decl = DECL_CONTEXT (decl);
2706     }
2707 }
2708
2709 /* Subroutine of cp_tree_equal: t1 and t2 are the CALL_EXPR_FNs of two
2710    CALL_EXPRS.  Return whether they are equivalent.  */
2711
2712 static bool
2713 called_fns_equal (tree t1, tree t2)
2714 {
2715   /* Core 1321: dependent names are equivalent even if the overload sets
2716      are different.  But do compare explicit template arguments.  */
2717   tree name1 = dependent_name (t1);
2718   tree name2 = dependent_name (t2);
2719   if (name1 || name2)
2720     {
2721       tree targs1 = NULL_TREE, targs2 = NULL_TREE;
2722
2723       if (name1 != name2)
2724         return false;
2725
2726       if (TREE_CODE (t1) == TEMPLATE_ID_EXPR)
2727         targs1 = TREE_OPERAND (t1, 1);
2728       if (TREE_CODE (t2) == TEMPLATE_ID_EXPR)
2729         targs2 = TREE_OPERAND (t2, 1);
2730       return cp_tree_equal (targs1, targs2);
2731     }
2732   else
2733     return cp_tree_equal (t1, t2);
2734 }
2735
2736 /* Return truthvalue of whether T1 is the same tree structure as T2.
2737    Return 1 if they are the same. Return 0 if they are different.  */
2738
2739 bool
2740 cp_tree_equal (tree t1, tree t2)
2741 {
2742   enum tree_code code1, code2;
2743
2744   if (t1 == t2)
2745     return true;
2746   if (!t1 || !t2)
2747     return false;
2748
2749   for (code1 = TREE_CODE (t1);
2750        CONVERT_EXPR_CODE_P (code1)
2751          || code1 == NON_LVALUE_EXPR;
2752        code1 = TREE_CODE (t1))
2753     t1 = TREE_OPERAND (t1, 0);
2754   for (code2 = TREE_CODE (t2);
2755        CONVERT_EXPR_CODE_P (code2)
2756          || code2 == NON_LVALUE_EXPR;
2757        code2 = TREE_CODE (t2))
2758     t2 = TREE_OPERAND (t2, 0);
2759
2760   /* They might have become equal now.  */
2761   if (t1 == t2)
2762     return true;
2763
2764   if (code1 != code2)
2765     return false;
2766
2767   switch (code1)
2768     {
2769     case VOID_CST:
2770       /* There's only a single VOID_CST node, so we should never reach
2771          here.  */
2772       gcc_unreachable ();
2773
2774     case INTEGER_CST:
2775       return tree_int_cst_equal (t1, t2);
2776
2777     case REAL_CST:
2778       return REAL_VALUES_EQUAL (TREE_REAL_CST (t1), TREE_REAL_CST (t2));
2779
2780     case STRING_CST:
2781       return TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
2782         && !memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
2783                     TREE_STRING_LENGTH (t1));
2784
2785     case FIXED_CST:
2786       return FIXED_VALUES_IDENTICAL (TREE_FIXED_CST (t1),
2787                                      TREE_FIXED_CST (t2));
2788
2789     case COMPLEX_CST:
2790       return cp_tree_equal (TREE_REALPART (t1), TREE_REALPART (t2))
2791         && cp_tree_equal (TREE_IMAGPART (t1), TREE_IMAGPART (t2));
2792
2793     case VECTOR_CST:
2794       return operand_equal_p (t1, t2, OEP_ONLY_CONST);
2795
2796     case CONSTRUCTOR:
2797       /* We need to do this when determining whether or not two
2798          non-type pointer to member function template arguments
2799          are the same.  */
2800       if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))
2801           || CONSTRUCTOR_NELTS (t1) != CONSTRUCTOR_NELTS (t2))
2802         return false;
2803       {
2804         tree field, value;
2805         unsigned int i;
2806         FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t1), i, field, value)
2807           {
2808             constructor_elt *elt2 = CONSTRUCTOR_ELT (t2, i);
2809             if (!cp_tree_equal (field, elt2->index)
2810                 || !cp_tree_equal (value, elt2->value))
2811               return false;
2812           }
2813       }
2814       return true;
2815
2816     case TREE_LIST:
2817       if (!cp_tree_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2)))
2818         return false;
2819       if (!cp_tree_equal (TREE_VALUE (t1), TREE_VALUE (t2)))
2820         return false;
2821       return cp_tree_equal (TREE_CHAIN (t1), TREE_CHAIN (t2));
2822
2823     case SAVE_EXPR:
2824       return cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
2825
2826     case CALL_EXPR:
2827       {
2828         tree arg1, arg2;
2829         call_expr_arg_iterator iter1, iter2;
2830         if (!called_fns_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
2831           return false;
2832         for (arg1 = first_call_expr_arg (t1, &iter1),
2833                arg2 = first_call_expr_arg (t2, &iter2);
2834              arg1 && arg2;
2835              arg1 = next_call_expr_arg (&iter1),
2836                arg2 = next_call_expr_arg (&iter2))
2837           if (!cp_tree_equal (arg1, arg2))
2838             return false;
2839         if (arg1 || arg2)
2840           return false;
2841         return true;
2842       }
2843
2844     case TARGET_EXPR:
2845       {
2846         tree o1 = TREE_OPERAND (t1, 0);
2847         tree o2 = TREE_OPERAND (t2, 0);
2848
2849         /* Special case: if either target is an unallocated VAR_DECL,
2850            it means that it's going to be unified with whatever the
2851            TARGET_EXPR is really supposed to initialize, so treat it
2852            as being equivalent to anything.  */
2853         if (VAR_P (o1) && DECL_NAME (o1) == NULL_TREE
2854             && !DECL_RTL_SET_P (o1))
2855           /*Nop*/;
2856         else if (VAR_P (o2) && DECL_NAME (o2) == NULL_TREE
2857                  && !DECL_RTL_SET_P (o2))
2858           /*Nop*/;
2859         else if (!cp_tree_equal (o1, o2))
2860           return false;
2861
2862         return cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
2863       }
2864
2865     case WITH_CLEANUP_EXPR:
2866       if (!cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0)))
2867         return false;
2868       return cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t1, 1));
2869
2870     case COMPONENT_REF:
2871       if (TREE_OPERAND (t1, 1) != TREE_OPERAND (t2, 1))
2872         return false;
2873       return cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
2874
2875     case PARM_DECL:
2876       /* For comparing uses of parameters in late-specified return types
2877          with an out-of-class definition of the function, but can also come
2878          up for expressions that involve 'this' in a member function
2879          template.  */
2880
2881       if (comparing_specializations)
2882         /* When comparing hash table entries, only an exact match is
2883            good enough; we don't want to replace 'this' with the
2884            version from another function.  */
2885         return false;
2886
2887       if (same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
2888         {
2889           if (DECL_ARTIFICIAL (t1) ^ DECL_ARTIFICIAL (t2))
2890             return false;
2891           if (DECL_ARTIFICIAL (t1)
2892               || (DECL_PARM_LEVEL (t1) == DECL_PARM_LEVEL (t2)
2893                   && DECL_PARM_INDEX (t1) == DECL_PARM_INDEX (t2)))
2894             return true;
2895         }
2896       return false;
2897
2898     case VAR_DECL:
2899     case CONST_DECL:
2900     case FIELD_DECL:
2901     case FUNCTION_DECL:
2902     case TEMPLATE_DECL:
2903     case IDENTIFIER_NODE:
2904     case SSA_NAME:
2905       return false;
2906
2907     case BASELINK:
2908       return (BASELINK_BINFO (t1) == BASELINK_BINFO (t2)
2909               && BASELINK_ACCESS_BINFO (t1) == BASELINK_ACCESS_BINFO (t2)
2910               && BASELINK_QUALIFIED_P (t1) == BASELINK_QUALIFIED_P (t2)
2911               && cp_tree_equal (BASELINK_FUNCTIONS (t1),
2912                                 BASELINK_FUNCTIONS (t2)));
2913
2914     case TEMPLATE_PARM_INDEX:
2915       return (TEMPLATE_PARM_IDX (t1) == TEMPLATE_PARM_IDX (t2)
2916               && TEMPLATE_PARM_LEVEL (t1) == TEMPLATE_PARM_LEVEL (t2)
2917               && (TEMPLATE_PARM_PARAMETER_PACK (t1)
2918                   == TEMPLATE_PARM_PARAMETER_PACK (t2))
2919               && same_type_p (TREE_TYPE (TEMPLATE_PARM_DECL (t1)),
2920                               TREE_TYPE (TEMPLATE_PARM_DECL (t2))));
2921
2922     case TEMPLATE_ID_EXPR:
2923       return (cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0))
2924               && cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1)));
2925
2926     case TREE_VEC:
2927       {
2928         unsigned ix;
2929         if (TREE_VEC_LENGTH (t1) != TREE_VEC_LENGTH (t2))
2930           return false;
2931         for (ix = TREE_VEC_LENGTH (t1); ix--;)
2932           if (!cp_tree_equal (TREE_VEC_ELT (t1, ix),
2933                               TREE_VEC_ELT (t2, ix)))
2934             return false;
2935         return true;
2936       }
2937
2938     case SIZEOF_EXPR:
2939     case ALIGNOF_EXPR:
2940       {
2941         tree o1 = TREE_OPERAND (t1, 0);
2942         tree o2 = TREE_OPERAND (t2, 0);
2943
2944         if (code1 == SIZEOF_EXPR)
2945           {
2946             if (SIZEOF_EXPR_TYPE_P (t1))
2947               o1 = TREE_TYPE (o1);
2948             if (SIZEOF_EXPR_TYPE_P (t2))
2949               o2 = TREE_TYPE (o2);
2950           }
2951         if (TREE_CODE (o1) != TREE_CODE (o2))
2952           return false;
2953         if (TYPE_P (o1))
2954           return same_type_p (o1, o2);
2955         else
2956           return cp_tree_equal (o1, o2);
2957       }
2958
2959     case MODOP_EXPR:
2960       {
2961         tree t1_op1, t2_op1;
2962
2963         if (!cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0)))
2964           return false;
2965
2966         t1_op1 = TREE_OPERAND (t1, 1);
2967         t2_op1 = TREE_OPERAND (t2, 1);
2968         if (TREE_CODE (t1_op1) != TREE_CODE (t2_op1))
2969           return false;
2970
2971         return cp_tree_equal (TREE_OPERAND (t1, 2), TREE_OPERAND (t2, 2));
2972       }
2973
2974     case PTRMEM_CST:
2975       /* Two pointer-to-members are the same if they point to the same
2976          field or function in the same class.  */
2977       if (PTRMEM_CST_MEMBER (t1) != PTRMEM_CST_MEMBER (t2))
2978         return false;
2979
2980       return same_type_p (PTRMEM_CST_CLASS (t1), PTRMEM_CST_CLASS (t2));
2981
2982     case OVERLOAD:
2983       if (OVL_FUNCTION (t1) != OVL_FUNCTION (t2))
2984         return false;
2985       return cp_tree_equal (OVL_CHAIN (t1), OVL_CHAIN (t2));
2986
2987     case TRAIT_EXPR:
2988       if (TRAIT_EXPR_KIND (t1) != TRAIT_EXPR_KIND (t2))
2989         return false;
2990       return same_type_p (TRAIT_EXPR_TYPE1 (t1), TRAIT_EXPR_TYPE1 (t2))
2991         && cp_tree_equal (TRAIT_EXPR_TYPE2 (t1), TRAIT_EXPR_TYPE2 (t2));
2992
2993     case CAST_EXPR:
2994     case STATIC_CAST_EXPR:
2995     case REINTERPRET_CAST_EXPR:
2996     case CONST_CAST_EXPR:
2997     case DYNAMIC_CAST_EXPR:
2998     case IMPLICIT_CONV_EXPR:
2999     case NEW_EXPR:
3000       if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
3001         return false;
3002       /* Now compare operands as usual.  */
3003       break;
3004
3005     case DEFERRED_NOEXCEPT:
3006       return (cp_tree_equal (DEFERRED_NOEXCEPT_PATTERN (t1),
3007                              DEFERRED_NOEXCEPT_PATTERN (t2))
3008               && comp_template_args (DEFERRED_NOEXCEPT_ARGS (t1),
3009                                      DEFERRED_NOEXCEPT_ARGS (t2)));
3010       break;
3011
3012     default:
3013       break;
3014     }
3015
3016   switch (TREE_CODE_CLASS (code1))
3017     {
3018     case tcc_unary:
3019     case tcc_binary:
3020     case tcc_comparison:
3021     case tcc_expression:
3022     case tcc_vl_exp:
3023     case tcc_reference:
3024     case tcc_statement:
3025       {
3026         int i, n;
3027
3028         n = cp_tree_operand_length (t1);
3029         if (TREE_CODE_CLASS (code1) == tcc_vl_exp
3030             && n != TREE_OPERAND_LENGTH (t2))
3031           return false;
3032
3033         for (i = 0; i < n; ++i)
3034           if (!cp_tree_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i)))
3035             return false;
3036
3037         return true;
3038       }
3039
3040     case tcc_type:
3041       return same_type_p (t1, t2);
3042     default:
3043       gcc_unreachable ();
3044     }
3045   /* We can get here with --disable-checking.  */
3046   return false;
3047 }
3048
3049 /* The type of ARG when used as an lvalue.  */
3050
3051 tree
3052 lvalue_type (tree arg)
3053 {
3054   tree type = TREE_TYPE (arg);
3055   return type;
3056 }
3057
3058 /* The type of ARG for printing error messages; denote lvalues with
3059    reference types.  */
3060
3061 tree
3062 error_type (tree arg)
3063 {
3064   tree type = TREE_TYPE (arg);
3065
3066   if (TREE_CODE (type) == ARRAY_TYPE)
3067     ;
3068   else if (TREE_CODE (type) == ERROR_MARK)
3069     ;
3070   else if (real_lvalue_p (arg))
3071     type = build_reference_type (lvalue_type (arg));
3072   else if (MAYBE_CLASS_TYPE_P (type))
3073     type = lvalue_type (arg);
3074
3075   return type;
3076 }
3077
3078 /* Does FUNCTION use a variable-length argument list?  */
3079
3080 int
3081 varargs_function_p (const_tree function)
3082 {
3083   return stdarg_p (TREE_TYPE (function));
3084 }
3085
3086 /* Returns 1 if decl is a member of a class.  */
3087
3088 int
3089 member_p (const_tree decl)
3090 {
3091   const_tree const ctx = DECL_CONTEXT (decl);
3092   return (ctx && TYPE_P (ctx));
3093 }
3094
3095 /* Create a placeholder for member access where we don't actually have an
3096    object that the access is against.  */
3097
3098 tree
3099 build_dummy_object (tree type)
3100 {
3101   tree decl = build1 (CONVERT_EXPR, build_pointer_type (type), void_node);
3102   return cp_build_indirect_ref (decl, RO_NULL, tf_warning_or_error);
3103 }
3104
3105 /* We've gotten a reference to a member of TYPE.  Return *this if appropriate,
3106    or a dummy object otherwise.  If BINFOP is non-0, it is filled with the
3107    binfo path from current_class_type to TYPE, or 0.  */
3108
3109 tree
3110 maybe_dummy_object (tree type, tree* binfop)
3111 {
3112   tree decl, context;
3113   tree binfo;
3114   tree current = current_nonlambda_class_type ();
3115
3116   if (current
3117       && (binfo = lookup_base (current, type, ba_any, NULL,
3118                                tf_warning_or_error)))
3119     context = current;
3120   else
3121     {
3122       /* Reference from a nested class member function.  */
3123       context = type;
3124       binfo = TYPE_BINFO (type);
3125     }
3126
3127   if (binfop)
3128     *binfop = binfo;
3129
3130   if (current_class_ref
3131       /* current_class_ref might not correspond to current_class_type if
3132          we're in tsubst_default_argument or a lambda-declarator; in either
3133          case, we want to use current_class_ref if it matches CONTEXT.  */
3134       && (same_type_ignoring_top_level_qualifiers_p
3135           (TREE_TYPE (current_class_ref), context)))
3136     decl = current_class_ref;
3137   else
3138     decl = build_dummy_object (context);
3139
3140   return decl;
3141 }
3142
3143 /* Returns 1 if OB is a placeholder object, or a pointer to one.  */
3144
3145 int
3146 is_dummy_object (const_tree ob)
3147 {
3148   if (INDIRECT_REF_P (ob))
3149     ob = TREE_OPERAND (ob, 0);
3150   return (TREE_CODE (ob) == CONVERT_EXPR
3151           && TREE_OPERAND (ob, 0) == void_node);
3152 }
3153
3154 /* Returns 1 iff type T is something we want to treat as a scalar type for
3155    the purpose of deciding whether it is trivial/POD/standard-layout.  */
3156
3157 bool
3158 scalarish_type_p (const_tree t)
3159 {
3160   if (t == error_mark_node)
3161     return 1;
3162
3163   return (SCALAR_TYPE_P (t)
3164           || TREE_CODE (t) == VECTOR_TYPE);
3165 }
3166
3167 /* Returns true iff T requires non-trivial default initialization.  */
3168
3169 bool
3170 type_has_nontrivial_default_init (const_tree t)
3171 {
3172   t = strip_array_types (CONST_CAST_TREE (t));
3173
3174   if (CLASS_TYPE_P (t))
3175     return TYPE_HAS_COMPLEX_DFLT (t);
3176   else
3177     return 0;
3178 }
3179
3180 /* Returns true iff copying an object of type T (including via move
3181    constructor) is non-trivial.  That is, T has no non-trivial copy
3182    constructors and no non-trivial move constructors.  */
3183
3184 bool
3185 type_has_nontrivial_copy_init (const_tree t)
3186 {
3187   t = strip_array_types (CONST_CAST_TREE (t));
3188
3189   if (CLASS_TYPE_P (t))
3190     {
3191       gcc_assert (COMPLETE_TYPE_P (t));
3192       return ((TYPE_HAS_COPY_CTOR (t)
3193                && TYPE_HAS_COMPLEX_COPY_CTOR (t))
3194               || TYPE_HAS_COMPLEX_MOVE_CTOR (t));
3195     }
3196   else
3197     return 0;
3198 }
3199
3200 /* Returns 1 iff type T is a trivially copyable type, as defined in
3201    [basic.types] and [class].  */
3202
3203 bool
3204 trivially_copyable_p (const_tree t)
3205 {
3206   t = strip_array_types (CONST_CAST_TREE (t));
3207
3208   if (CLASS_TYPE_P (t))
3209     return ((!TYPE_HAS_COPY_CTOR (t)
3210              || !TYPE_HAS_COMPLEX_COPY_CTOR (t))
3211             && !TYPE_HAS_COMPLEX_MOVE_CTOR (t)
3212             && (!TYPE_HAS_COPY_ASSIGN (t)
3213                 || !TYPE_HAS_COMPLEX_COPY_ASSIGN (t))
3214             && !TYPE_HAS_COMPLEX_MOVE_ASSIGN (t)
3215             && TYPE_HAS_TRIVIAL_DESTRUCTOR (t));
3216   else
3217     return !CP_TYPE_VOLATILE_P (t) && scalarish_type_p (t);
3218 }
3219
3220 /* Returns 1 iff type T is a trivial type, as defined in [basic.types] and
3221    [class].  */
3222
3223 bool
3224 trivial_type_p (const_tree t)
3225 {
3226   t = strip_array_types (CONST_CAST_TREE (t));
3227
3228   if (CLASS_TYPE_P (t))
3229     return (TYPE_HAS_TRIVIAL_DFLT (t)
3230             && trivially_copyable_p (t));
3231   else
3232     return scalarish_type_p (t);
3233 }
3234
3235 /* Returns 1 iff type T is a POD type, as defined in [basic.types].  */
3236
3237 bool
3238 pod_type_p (const_tree t)
3239 {
3240   /* This CONST_CAST is okay because strip_array_types returns its
3241      argument unmodified and we assign it to a const_tree.  */
3242   t = strip_array_types (CONST_CAST_TREE(t));
3243
3244   if (!CLASS_TYPE_P (t))
3245     return scalarish_type_p (t);
3246   else if (cxx_dialect > cxx98)
3247     /* [class]/10: A POD struct is a class that is both a trivial class and a
3248        standard-layout class, and has no non-static data members of type
3249        non-POD struct, non-POD union (or array of such types).
3250
3251        We don't need to check individual members because if a member is
3252        non-std-layout or non-trivial, the class will be too.  */
3253     return (std_layout_type_p (t) && trivial_type_p (t));
3254   else
3255     /* The C++98 definition of POD is different.  */
3256     return !CLASSTYPE_NON_LAYOUT_POD_P (t);
3257 }
3258
3259 /* Returns true iff T is POD for the purpose of layout, as defined in the
3260    C++ ABI.  */
3261
3262 bool
3263 layout_pod_type_p (const_tree t)
3264 {
3265   t = strip_array_types (CONST_CAST_TREE (t));
3266
3267   if (CLASS_TYPE_P (t))
3268     return !CLASSTYPE_NON_LAYOUT_POD_P (t);
3269   else
3270     return scalarish_type_p (t);
3271 }
3272
3273 /* Returns true iff T is a standard-layout type, as defined in
3274    [basic.types].  */
3275
3276 bool
3277 std_layout_type_p (const_tree t)
3278 {
3279   t = strip_array_types (CONST_CAST_TREE (t));
3280
3281   if (CLASS_TYPE_P (t))
3282     return !CLASSTYPE_NON_STD_LAYOUT (t);
3283   else
3284     return scalarish_type_p (t);
3285 }
3286
3287 /* Nonzero iff type T is a class template implicit specialization.  */
3288
3289 bool
3290 class_tmpl_impl_spec_p (const_tree t)
3291 {
3292   return CLASS_TYPE_P (t) && CLASSTYPE_TEMPLATE_INSTANTIATION (t);
3293 }
3294
3295 /* Returns 1 iff zero initialization of type T means actually storing
3296    zeros in it.  */
3297
3298 int
3299 zero_init_p (const_tree t)
3300 {
3301   /* This CONST_CAST is okay because strip_array_types returns its
3302      argument unmodified and we assign it to a const_tree.  */
3303   t = strip_array_types (CONST_CAST_TREE(t));
3304
3305   if (t == error_mark_node)
3306     return 1;
3307
3308   /* NULL pointers to data members are initialized with -1.  */
3309   if (TYPE_PTRDATAMEM_P (t))
3310     return 0;
3311
3312   /* Classes that contain types that can't be zero-initialized, cannot
3313      be zero-initialized themselves.  */
3314   if (CLASS_TYPE_P (t) && CLASSTYPE_NON_ZERO_INIT_P (t))
3315     return 0;
3316
3317   return 1;
3318 }
3319
3320 /* Table of valid C++ attributes.  */
3321 const struct attribute_spec cxx_attribute_table[] =
3322 {
3323   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, decl_handler,
3324        type_handler, affects_type_identity } */
3325   { "java_interface", 0, 0, false, false, false,
3326     handle_java_interface_decl_attribute, handle_java_interface_type_attribute,
3327     false },
3328   { "com_interface",  0, 0, false, false, false,
3329     handle_com_interface_decl_attribute, handle_com_interface_type_attribute,
3330     false },
3331   { "init_priority",  1, 1, true,  false, false,
3332     handle_init_priority_attribute, NULL, false },
3333   { "abi_tag", 1, -1, false, false, false,
3334     handle_abi_tag_decl_attribute, handle_abi_tag_type_attribute, true },
3335   { NULL,             0, 0, false, false, false, NULL, NULL, false }
3336 };
3337
3338
3339 static tree
3340 handle_java_interface_decl_attribute (tree* /*node*/, tree name, tree /*args*/,
3341                                       int /*flags*/, bool* no_add_attrs)
3342 {
3343   error ("%qE attribute can only be applied to Java class definitions", name);
3344   *no_add_attrs = true;
3345   return NULL_TREE;
3346 }
3347
3348 static tree
3349 handle_com_interface_decl_attribute (tree* /*node*/, tree name, tree /*args*/,
3350                                      int /*flags*/, bool* no_add_attrs)
3351 {
3352   warning (OPT_Wattributes, "%qE attribute can only be applied "
3353            "to class definitions", name);
3354   *no_add_attrs = true;
3355   return NULL_TREE;
3356 }
3357
3358 /* Handle a "java_interface" attribute; arguments as in
3359    struct attribute_spec.handler.  */
3360 static tree
3361 handle_java_interface_type_attribute (tree* node,
3362                                       tree name,
3363                                       tree /*args*/,
3364                                       int flags,
3365                                       bool* no_add_attrs)
3366 {
3367   if (!CLASS_TYPE_P (*node) || !TYPE_FOR_JAVA (*node))
3368     {
3369       error ("%qE attribute can only be applied to Java class definitions",
3370              name);
3371       *no_add_attrs = true;
3372       return NULL_TREE;
3373     }
3374   if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
3375     *node = build_variant_type_copy (*node);
3376   TYPE_JAVA_INTERFACE (*node) = 1;
3377
3378   return NULL_TREE;
3379 }
3380
3381 /* Handle a "com_interface" attribute; arguments as in
3382    struct attribute_spec.handler.  */
3383 static tree
3384 handle_com_interface_type_attribute (tree* node,
3385                                      tree name,
3386                                      tree /*args*/,
3387                                      int /*flags*/,
3388                                      bool* no_add_attrs)
3389 {
3390   static int warned;
3391
3392   *no_add_attrs = true;
3393
3394   if (!CLASS_TYPE_P (*node) || *node != TYPE_MAIN_VARIANT (*node))
3395     {
3396       warning (OPT_Wattributes, "%qE attribute can only be applied "
3397                "to class definitions", name);
3398       return NULL_TREE;
3399     }
3400
3401   if (!warned++)
3402     warning (0, "%qE is obsolete; g++ vtables are now COM-compatible by default",
3403              name);
3404
3405   return NULL_TREE;
3406 }
3407
3408 /* Handle an "init_priority" attribute; arguments as in
3409    struct attribute_spec.handler.  */
3410 static tree
3411 handle_init_priority_attribute (tree* node,
3412                                 tree name,
3413                                 tree args,
3414                                 int /*flags*/,
3415                                 bool* no_add_attrs)
3416 {
3417   tree initp_expr = TREE_VALUE (args);
3418   tree decl = *node;
3419   tree type = TREE_TYPE (decl);
3420   int pri;
3421
3422   STRIP_NOPS (initp_expr);
3423   initp_expr = default_conversion (initp_expr);
3424
3425   if (!initp_expr || TREE_CODE (initp_expr) != INTEGER_CST)
3426     {
3427       error ("requested init_priority is not an integer constant");
3428       *no_add_attrs = true;
3429       return NULL_TREE;
3430     }
3431
3432   pri = TREE_INT_CST_LOW (initp_expr);
3433
3434   type = strip_array_types (type);
3435
3436   if (decl == NULL_TREE
3437       || !VAR_P (decl)
3438       || !TREE_STATIC (decl)
3439       || DECL_EXTERNAL (decl)
3440       || (TREE_CODE (type) != RECORD_TYPE
3441           && TREE_CODE (type) != UNION_TYPE)
3442       /* Static objects in functions are initialized the
3443          first time control passes through that
3444          function. This is not precise enough to pin down an
3445          init_priority value, so don't allow it.  */
3446       || current_function_decl)
3447     {
3448       error ("can only use %qE attribute on file-scope definitions "
3449              "of objects of class type", name);
3450       *no_add_attrs = true;
3451       return NULL_TREE;
3452     }
3453
3454   if (pri > MAX_INIT_PRIORITY || pri <= 0)
3455     {
3456       error ("requested init_priority is out of range");
3457       *no_add_attrs = true;
3458       return NULL_TREE;
3459     }
3460
3461   /* Check for init_priorities that are reserved for
3462      language and runtime support implementations.*/
3463   if (pri <= MAX_RESERVED_INIT_PRIORITY)
3464     {
3465       warning
3466         (0, "requested init_priority is reserved for internal use");
3467     }
3468
3469   if (SUPPORTS_INIT_PRIORITY)
3470     {
3471       SET_DECL_INIT_PRIORITY (decl, pri);
3472       DECL_HAS_INIT_PRIORITY_P (decl) = 1;
3473       return NULL_TREE;
3474     }
3475   else
3476     {
3477       error ("%qE attribute is not supported on this platform", name);
3478       *no_add_attrs = true;
3479       return NULL_TREE;
3480     }
3481 }
3482
3483 /* DECL is being redeclared; the old declaration had the abi tags in OLD,
3484    and the new one has the tags in NEW_.  Give an error if there are tags
3485    in NEW_ that weren't in OLD.  */
3486
3487 bool
3488 check_abi_tag_redeclaration (const_tree decl, const_tree old, const_tree new_)
3489 {
3490   if (old && TREE_CODE (TREE_VALUE (old)) == TREE_LIST)
3491     old = TREE_VALUE (old);
3492   if (new_ && TREE_CODE (TREE_VALUE (new_)) == TREE_LIST)
3493     new_ = TREE_VALUE (new_);
3494   bool err = false;
3495   for (const_tree t = new_; t; t = TREE_CHAIN (t))
3496     {
3497       tree str = TREE_VALUE (t);
3498       for (const_tree in = old; in; in = TREE_CHAIN (in))
3499         {
3500           tree ostr = TREE_VALUE (in);
3501           if (cp_tree_equal (str, ostr))
3502             goto found;
3503         }
3504       error ("redeclaration of %qD adds abi tag %E", decl, str);
3505       err = true;
3506     found:;
3507     }
3508   if (err)
3509     {
3510       inform (DECL_SOURCE_LOCATION (decl), "previous declaration here");
3511       return false;
3512     }
3513   return true;
3514 }
3515
3516 /* Handle an "abi_tag" attribute; arguments as in
3517    struct attribute_spec.handler.  */
3518
3519 static tree
3520 handle_abi_tag_decl_attribute (tree* node, tree name, tree /*args*/,
3521                                int /*flags*/, bool* no_add_attrs)
3522 {
3523   if (TREE_CODE (*node) != FUNCTION_DECL)
3524     {
3525       error ("%qE attribute applied to non-function %qD", name, *node);
3526       *no_add_attrs = true;
3527     }
3528   else if (DECL_LANGUAGE (*node) == lang_c)
3529     {
3530       error ("%qE attribute applied to extern \"C\" function %qD",
3531              name, *node);
3532       *no_add_attrs = true;
3533     }
3534
3535   return NULL_TREE;
3536 }
3537
3538
3539 static tree
3540 handle_abi_tag_type_attribute (tree* node, tree name, tree args,
3541                           int flags, bool* no_add_attrs)
3542 {
3543   if (!OVERLOAD_TYPE_P (*node))
3544     {
3545       error ("%qE attribute applied to non-class, non-enum type %qT",
3546              name, *node);
3547       *no_add_attrs = true;
3548     }
3549   else if (!(flags & (int)ATTR_FLAG_TYPE_IN_PLACE))
3550     {
3551       error ("%qE attribute applied to %qT after its definition",
3552              name, *node);
3553       *no_add_attrs = true;
3554     }
3555   else if (CLASSTYPE_TEMPLATE_INSTANTIATION (*node))
3556     {
3557       warning (OPT_Wattributes, "ignoring %qE attribute applied to "
3558                "template instantiation %qT", name, *node);
3559       *no_add_attrs = true;
3560     }
3561   else if (CLASSTYPE_TEMPLATE_SPECIALIZATION (*node))
3562     {
3563       warning (OPT_Wattributes, "ignoring %qE attribute applied to "
3564                "template specialization %qT", name, *node);
3565       *no_add_attrs = true;
3566     }
3567   else
3568     {
3569       tree attributes = TYPE_ATTRIBUTES (*node);
3570       tree decl = TYPE_NAME (*node);
3571
3572       /* Make sure all declarations have the same abi tags.  */
3573       if (DECL_SOURCE_LOCATION (decl) != input_location)
3574         {
3575           if (!check_abi_tag_redeclaration (decl,
3576                                             lookup_attribute ("abi_tag",
3577                                                               attributes),
3578                                             args))
3579             *no_add_attrs = true;
3580         }
3581      }
3582
3583   return NULL_TREE;
3584 }
3585
3586 /* Return a new PTRMEM_CST of the indicated TYPE.  The MEMBER is the
3587    thing pointed to by the constant.  */
3588
3589 tree
3590 make_ptrmem_cst (tree type, tree member)
3591 {
3592   tree ptrmem_cst = make_node (PTRMEM_CST);
3593   TREE_TYPE (ptrmem_cst) = type;
3594   PTRMEM_CST_MEMBER (ptrmem_cst) = member;
3595   return ptrmem_cst;
3596 }
3597
3598 /* Build a variant of TYPE that has the indicated ATTRIBUTES.  May
3599    return an existing type if an appropriate type already exists.  */
3600
3601 tree
3602 cp_build_type_attribute_variant (tree type, tree attributes)
3603 {
3604   tree new_type;
3605
3606   new_type = build_type_attribute_variant (type, attributes);
3607   if (TREE_CODE (new_type) == FUNCTION_TYPE
3608       || TREE_CODE (new_type) == METHOD_TYPE)
3609     {
3610       new_type = build_exception_variant (new_type,
3611                                           TYPE_RAISES_EXCEPTIONS (type));
3612       new_type = build_ref_qualified_type (new_type,
3613                                            type_memfn_rqual (type));
3614     }
3615
3616   /* Making a new main variant of a class type is broken.  */
3617   gcc_assert (!CLASS_TYPE_P (type) || new_type == type);
3618
3619   return new_type;
3620 }
3621
3622 /* Return TRUE if TYPE1 and TYPE2 are identical for type hashing purposes.
3623    Called only after doing all language independent checks.  Only
3624    to check TYPE_RAISES_EXCEPTIONS for FUNCTION_TYPE, the rest is already
3625    compared in type_hash_eq.  */
3626
3627 bool
3628 cxx_type_hash_eq (const_tree typea, const_tree typeb)
3629 {
3630   gcc_assert (TREE_CODE (typea) == FUNCTION_TYPE
3631               || TREE_CODE (typea) == METHOD_TYPE);
3632
3633   return comp_except_specs (TYPE_RAISES_EXCEPTIONS (typea),
3634                             TYPE_RAISES_EXCEPTIONS (typeb), ce_exact);
3635 }
3636
3637 /* Apply FUNC to all language-specific sub-trees of TP in a pre-order
3638    traversal.  Called from walk_tree.  */
3639
3640 tree
3641 cp_walk_subtrees (tree *tp, int *walk_subtrees_p, walk_tree_fn func,
3642                   void *data, hash_set<tree> *pset)
3643 {
3644   enum tree_code code = TREE_CODE (*tp);
3645   tree result;
3646
3647 #define WALK_SUBTREE(NODE)                              \
3648   do                                                    \
3649     {                                                   \
3650       result = cp_walk_tree (&(NODE), func, data, pset);        \
3651       if (result) goto out;                             \
3652     }                                                   \
3653   while (0)
3654
3655   /* Not one of the easy cases.  We must explicitly go through the
3656      children.  */
3657   result = NULL_TREE;
3658   switch (code)
3659     {
3660     case DEFAULT_ARG:
3661     case TEMPLATE_TEMPLATE_PARM:
3662     case BOUND_TEMPLATE_TEMPLATE_PARM:
3663     case UNBOUND_CLASS_TEMPLATE:
3664     case TEMPLATE_PARM_INDEX:
3665     case TEMPLATE_TYPE_PARM:
3666     case TYPENAME_TYPE:
3667     case TYPEOF_TYPE:
3668     case UNDERLYING_TYPE:
3669       /* None of these have subtrees other than those already walked
3670          above.  */
3671       *walk_subtrees_p = 0;
3672       break;
3673
3674     case BASELINK:
3675       WALK_SUBTREE (BASELINK_FUNCTIONS (*tp));
3676       *walk_subtrees_p = 0;
3677       break;
3678
3679     case PTRMEM_CST:
3680       WALK_SUBTREE (TREE_TYPE (*tp));
3681       *walk_subtrees_p = 0;
3682       break;
3683
3684     case TREE_LIST:
3685       WALK_SUBTREE (TREE_PURPOSE (*tp));
3686       break;
3687
3688     case OVERLOAD:
3689       WALK_SUBTREE (OVL_FUNCTION (*tp));
3690       WALK_SUBTREE (OVL_CHAIN (*tp));
3691       *walk_subtrees_p = 0;
3692       break;
3693
3694     case USING_DECL:
3695       WALK_SUBTREE (DECL_NAME (*tp));
3696       WALK_SUBTREE (USING_DECL_SCOPE (*tp));
3697       WALK_SUBTREE (USING_DECL_DECLS (*tp));
3698       *walk_subtrees_p = 0;
3699       break;
3700
3701     case RECORD_TYPE:
3702       if (TYPE_PTRMEMFUNC_P (*tp))
3703         WALK_SUBTREE (TYPE_PTRMEMFUNC_FN_TYPE_RAW (*tp));
3704       break;
3705
3706     case TYPE_ARGUMENT_PACK:
3707     case NONTYPE_ARGUMENT_PACK:
3708       {
3709         tree args = ARGUMENT_PACK_ARGS (*tp);
3710         int i, len = TREE_VEC_LENGTH (args);
3711         for (i = 0; i < len; i++)
3712           WALK_SUBTREE (TREE_VEC_ELT (args, i));
3713       }
3714       break;
3715
3716     case TYPE_PACK_EXPANSION:
3717       WALK_SUBTREE (TREE_TYPE (*tp));
3718       WALK_SUBTREE (PACK_EXPANSION_EXTRA_ARGS (*tp));
3719       *walk_subtrees_p = 0;
3720       break;
3721
3722     case EXPR_PACK_EXPANSION:
3723       WALK_SUBTREE (TREE_OPERAND (*tp, 0));
3724       WALK_SUBTREE (PACK_EXPANSION_EXTRA_ARGS (*tp));
3725       *walk_subtrees_p = 0;
3726       break;
3727
3728     case CAST_EXPR:
3729     case REINTERPRET_CAST_EXPR:
3730     case STATIC_CAST_EXPR:
3731     case CONST_CAST_EXPR:
3732     case DYNAMIC_CAST_EXPR:
3733     case IMPLICIT_CONV_EXPR:
3734       if (TREE_TYPE (*tp))
3735         WALK_SUBTREE (TREE_TYPE (*tp));
3736
3737       {
3738         int i;
3739         for (i = 0; i < TREE_CODE_LENGTH (TREE_CODE (*tp)); ++i)
3740           WALK_SUBTREE (TREE_OPERAND (*tp, i));
3741       }
3742       *walk_subtrees_p = 0;
3743       break;
3744
3745     case TRAIT_EXPR:
3746       WALK_SUBTREE (TRAIT_EXPR_TYPE1 (*tp));
3747       WALK_SUBTREE (TRAIT_EXPR_TYPE2 (*tp));
3748       *walk_subtrees_p = 0;
3749       break;
3750
3751     case DECLTYPE_TYPE:
3752       WALK_SUBTREE (DECLTYPE_TYPE_EXPR (*tp));
3753       *walk_subtrees_p = 0;
3754       break;
3755
3756
3757     default:
3758       return NULL_TREE;
3759     }
3760
3761   /* We didn't find what we were looking for.  */
3762  out:
3763   return result;
3764
3765 #undef WALK_SUBTREE
3766 }
3767
3768 /* Like save_expr, but for C++.  */
3769
3770 tree
3771 cp_save_expr (tree expr)
3772 {
3773   /* There is no reason to create a SAVE_EXPR within a template; if
3774      needed, we can create the SAVE_EXPR when instantiating the
3775      template.  Furthermore, the middle-end cannot handle C++-specific
3776      tree codes.  */
3777   if (processing_template_decl)
3778     return expr;
3779   return save_expr (expr);
3780 }
3781
3782 /* Initialize tree.c.  */
3783
3784 void
3785 init_tree (void)
3786 {
3787   list_hash_table = hash_table<list_hasher>::create_ggc (61);
3788 }
3789
3790 /* Returns the kind of special function that DECL (a FUNCTION_DECL)
3791    is.  Note that sfk_none is zero, so this function can be used as a
3792    predicate to test whether or not DECL is a special function.  */
3793
3794 special_function_kind
3795 special_function_p (const_tree decl)
3796 {
3797   /* Rather than doing all this stuff with magic names, we should
3798      probably have a field of type `special_function_kind' in
3799      DECL_LANG_SPECIFIC.  */
3800   if (DECL_INHERITED_CTOR_BASE (decl))
3801     return sfk_inheriting_constructor;
3802   if (DECL_COPY_CONSTRUCTOR_P (decl))
3803     return sfk_copy_constructor;
3804   if (DECL_MOVE_CONSTRUCTOR_P (decl))
3805     return sfk_move_constructor;
3806   if (DECL_CONSTRUCTOR_P (decl))
3807     return sfk_constructor;
3808   if (DECL_OVERLOADED_OPERATOR_P (decl) == NOP_EXPR)
3809     {
3810       if (copy_fn_p (decl))
3811         return sfk_copy_assignment;
3812       if (move_fn_p (decl))
3813         return sfk_move_assignment;
3814     }
3815   if (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (decl))
3816     return sfk_destructor;
3817   if (DECL_COMPLETE_DESTRUCTOR_P (decl))
3818     return sfk_complete_destructor;
3819   if (DECL_BASE_DESTRUCTOR_P (decl))
3820     return sfk_base_destructor;
3821   if (DECL_DELETING_DESTRUCTOR_P (decl))
3822     return sfk_deleting_destructor;
3823   if (DECL_CONV_FN_P (decl))
3824     return sfk_conversion;
3825
3826   return sfk_none;
3827 }
3828
3829 /* Returns nonzero if TYPE is a character type, including wchar_t.  */
3830
3831 int
3832 char_type_p (tree type)
3833 {
3834   return (same_type_p (type, char_type_node)
3835           || same_type_p (type, unsigned_char_type_node)
3836           || same_type_p (type, signed_char_type_node)
3837           || same_type_p (type, char16_type_node)
3838           || same_type_p (type, char32_type_node)
3839           || same_type_p (type, wchar_type_node));
3840 }
3841
3842 /* Returns the kind of linkage associated with the indicated DECL.  Th
3843    value returned is as specified by the language standard; it is
3844    independent of implementation details regarding template
3845    instantiation, etc.  For example, it is possible that a declaration
3846    to which this function assigns external linkage would not show up
3847    as a global symbol when you run `nm' on the resulting object file.  */
3848
3849 linkage_kind
3850 decl_linkage (tree decl)
3851 {
3852   /* This function doesn't attempt to calculate the linkage from first
3853      principles as given in [basic.link].  Instead, it makes use of
3854      the fact that we have already set TREE_PUBLIC appropriately, and
3855      then handles a few special cases.  Ideally, we would calculate
3856      linkage first, and then transform that into a concrete
3857      implementation.  */
3858
3859   /* Things that don't have names have no linkage.  */
3860   if (!DECL_NAME (decl))
3861     return lk_none;
3862
3863   /* Fields have no linkage.  */
3864   if (TREE_CODE (decl) == FIELD_DECL)
3865     return lk_none;
3866
3867   /* Things that are TREE_PUBLIC have external linkage.  */
3868   if (TREE_PUBLIC (decl))
3869     return lk_external;
3870
3871   if (TREE_CODE (decl) == NAMESPACE_DECL)
3872     return lk_external;
3873
3874   /* Linkage of a CONST_DECL depends on the linkage of the enumeration
3875      type.  */
3876   if (TREE_CODE (decl) == CONST_DECL)
3877     return decl_linkage (TYPE_NAME (DECL_CONTEXT (decl)));
3878
3879   /* Things in local scope do not have linkage, if they don't have
3880      TREE_PUBLIC set.  */
3881   if (decl_function_context (decl))
3882     return lk_none;
3883
3884   /* Members of the anonymous namespace also have TREE_PUBLIC unset, but
3885      are considered to have external linkage for language purposes, as do
3886      template instantiations on targets without weak symbols.  DECLs really
3887      meant to have internal linkage have DECL_THIS_STATIC set.  */
3888   if (TREE_CODE (decl) == TYPE_DECL)
3889     return lk_external;
3890   if (VAR_OR_FUNCTION_DECL_P (decl))
3891     {
3892       if (!DECL_THIS_STATIC (decl))
3893         return lk_external;
3894
3895       /* Static data members and static member functions from classes
3896          in anonymous namespace also don't have TREE_PUBLIC set.  */
3897       if (DECL_CLASS_CONTEXT (decl))
3898         return lk_external;
3899     }
3900
3901   /* Everything else has internal linkage.  */
3902   return lk_internal;
3903 }
3904
3905 /* Returns the storage duration of the object or reference associated with
3906    the indicated DECL, which should be a VAR_DECL or PARM_DECL.  */
3907
3908 duration_kind
3909 decl_storage_duration (tree decl)
3910 {
3911   if (TREE_CODE (decl) == PARM_DECL)
3912     return dk_auto;
3913   if (TREE_CODE (decl) == FUNCTION_DECL)
3914     return dk_static;
3915   gcc_assert (VAR_P (decl));
3916   if (!TREE_STATIC (decl)
3917       && !DECL_EXTERNAL (decl))
3918     return dk_auto;
3919   if (DECL_THREAD_LOCAL_P (decl))
3920     return dk_thread;
3921   return dk_static;
3922 }
3923 \f
3924 /* EXP is an expression that we want to pre-evaluate.  Returns (in
3925    *INITP) an expression that will perform the pre-evaluation.  The
3926    value returned by this function is a side-effect free expression
3927    equivalent to the pre-evaluated expression.  Callers must ensure
3928    that *INITP is evaluated before EXP.  */
3929
3930 tree
3931 stabilize_expr (tree exp, tree* initp)
3932 {
3933   tree init_expr;
3934
3935   if (!TREE_SIDE_EFFECTS (exp))
3936     init_expr = NULL_TREE;
3937   else if (VOID_TYPE_P (TREE_TYPE (exp)))
3938     {
3939       init_expr = exp;
3940       exp = void_node;
3941     }
3942   /* There are no expressions with REFERENCE_TYPE, but there can be call
3943      arguments with such a type; just treat it as a pointer.  */
3944   else if (TREE_CODE (TREE_TYPE (exp)) == REFERENCE_TYPE
3945            || SCALAR_TYPE_P (TREE_TYPE (exp))
3946            || !lvalue_or_rvalue_with_address_p (exp))
3947     {
3948       init_expr = get_target_expr (exp);
3949       exp = TARGET_EXPR_SLOT (init_expr);
3950       if (CLASS_TYPE_P (TREE_TYPE (exp)))
3951         exp = move (exp);
3952       else
3953         exp = rvalue (exp);
3954     }
3955   else
3956     {
3957       bool xval = !real_lvalue_p (exp);
3958       exp = cp_build_addr_expr (exp, tf_warning_or_error);
3959       init_expr = get_target_expr (exp);
3960       exp = TARGET_EXPR_SLOT (init_expr);
3961       exp = cp_build_indirect_ref (exp, RO_NULL, tf_warning_or_error);
3962       if (xval)
3963         exp = move (exp);
3964     }
3965   *initp = init_expr;
3966
3967   gcc_assert (!TREE_SIDE_EFFECTS (exp));
3968   return exp;
3969 }
3970
3971 /* Add NEW_EXPR, an expression whose value we don't care about, after the
3972    similar expression ORIG.  */
3973
3974 tree
3975 add_stmt_to_compound (tree orig, tree new_expr)
3976 {
3977   if (!new_expr || !TREE_SIDE_EFFECTS (new_expr))
3978     return orig;
3979   if (!orig || !TREE_SIDE_EFFECTS (orig))
3980     return new_expr;
3981   return build2 (COMPOUND_EXPR, void_type_node, orig, new_expr);
3982 }
3983
3984 /* Like stabilize_expr, but for a call whose arguments we want to
3985    pre-evaluate.  CALL is modified in place to use the pre-evaluated
3986    arguments, while, upon return, *INITP contains an expression to
3987    compute the arguments.  */
3988
3989 void
3990 stabilize_call (tree call, tree *initp)
3991 {
3992   tree inits = NULL_TREE;
3993   int i;
3994   int nargs = call_expr_nargs (call);
3995
3996   if (call == error_mark_node || processing_template_decl)
3997     {
3998       *initp = NULL_TREE;
3999       return;
4000     }
4001
4002   gcc_assert (TREE_CODE (call) == CALL_EXPR);
4003
4004   for (i = 0; i < nargs; i++)
4005     {
4006       tree init;
4007       CALL_EXPR_ARG (call, i) =
4008         stabilize_expr (CALL_EXPR_ARG (call, i), &init);
4009       inits = add_stmt_to_compound (inits, init);
4010     }
4011
4012   *initp = inits;
4013 }
4014
4015 /* Like stabilize_expr, but for an AGGR_INIT_EXPR whose arguments we want
4016    to pre-evaluate.  CALL is modified in place to use the pre-evaluated
4017    arguments, while, upon return, *INITP contains an expression to
4018    compute the arguments.  */
4019
4020 static void
4021 stabilize_aggr_init (tree call, tree *initp)
4022 {
4023   tree inits = NULL_TREE;
4024   int i;
4025   int nargs = aggr_init_expr_nargs (call);
4026
4027   if (call == error_mark_node)
4028     return;
4029
4030   gcc_assert (TREE_CODE (call) == AGGR_INIT_EXPR);
4031
4032   for (i = 0; i < nargs; i++)
4033     {
4034       tree init;
4035       AGGR_INIT_EXPR_ARG (call, i) =
4036         stabilize_expr (AGGR_INIT_EXPR_ARG (call, i), &init);
4037       inits = add_stmt_to_compound (inits, init);
4038     }
4039
4040   *initp = inits;
4041 }
4042
4043 /* Like stabilize_expr, but for an initialization.
4044
4045    If the initialization is for an object of class type, this function
4046    takes care not to introduce additional temporaries.
4047
4048    Returns TRUE iff the expression was successfully pre-evaluated,
4049    i.e., if INIT is now side-effect free, except for, possibly, a
4050    single call to a constructor.  */
4051
4052 bool
4053 stabilize_init (tree init, tree *initp)
4054 {
4055   tree t = init;
4056
4057   *initp = NULL_TREE;
4058
4059   if (t == error_mark_node || processing_template_decl)
4060     return true;
4061
4062   if (TREE_CODE (t) == INIT_EXPR)
4063     t = TREE_OPERAND (t, 1);
4064   if (TREE_CODE (t) == TARGET_EXPR)
4065     t = TARGET_EXPR_INITIAL (t);
4066
4067   /* If the RHS can be stabilized without breaking copy elision, stabilize
4068      it.  We specifically don't stabilize class prvalues here because that
4069      would mean an extra copy, but they might be stabilized below.  */
4070   if (TREE_CODE (init) == INIT_EXPR
4071       && TREE_CODE (t) != CONSTRUCTOR
4072       && TREE_CODE (t) != AGGR_INIT_EXPR
4073       && (SCALAR_TYPE_P (TREE_TYPE (t))
4074           || lvalue_or_rvalue_with_address_p (t)))
4075     {
4076       TREE_OPERAND (init, 1) = stabilize_expr (t, initp);
4077       return true;
4078     }
4079
4080   if (TREE_CODE (t) == COMPOUND_EXPR
4081       && TREE_CODE (init) == INIT_EXPR)
4082     {
4083       tree last = expr_last (t);
4084       /* Handle stabilizing the EMPTY_CLASS_EXPR pattern.  */
4085       if (!TREE_SIDE_EFFECTS (last))
4086         {
4087           *initp = t;
4088           TREE_OPERAND (init, 1) = last;
4089           return true;
4090         }
4091     }
4092
4093   if (TREE_CODE (t) == CONSTRUCTOR)
4094     {
4095       /* Aggregate initialization: stabilize each of the field
4096          initializers.  */
4097       unsigned i;
4098       constructor_elt *ce;
4099       bool good = true;
4100       vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t);
4101       for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
4102         {
4103           tree type = TREE_TYPE (ce->value);
4104           tree subinit;
4105           if (TREE_CODE (type) == REFERENCE_TYPE
4106               || SCALAR_TYPE_P (type))
4107             ce->value = stabilize_expr (ce->value, &subinit);
4108           else if (!stabilize_init (ce->value, &subinit))
4109             good = false;
4110           *initp = add_stmt_to_compound (*initp, subinit);
4111         }
4112       return good;
4113     }
4114
4115   if (TREE_CODE (t) == CALL_EXPR)
4116     {
4117       stabilize_call (t, initp);
4118       return true;
4119     }
4120
4121   if (TREE_CODE (t) == AGGR_INIT_EXPR)
4122     {
4123       stabilize_aggr_init (t, initp);
4124       return true;
4125     }
4126
4127   /* The initialization is being performed via a bitwise copy -- and
4128      the item copied may have side effects.  */
4129   return !TREE_SIDE_EFFECTS (init);
4130 }
4131
4132 /* Like "fold", but should be used whenever we might be processing the
4133    body of a template.  */
4134
4135 tree
4136 fold_if_not_in_template (tree expr)
4137 {
4138   /* In the body of a template, there is never any need to call
4139      "fold".  We will call fold later when actually instantiating the
4140      template.  Integral constant expressions in templates will be
4141      evaluated via instantiate_non_dependent_expr, as necessary.  */
4142   if (processing_template_decl)
4143     return expr;
4144
4145   /* Fold C++ front-end specific tree codes.  */
4146   if (TREE_CODE (expr) == UNARY_PLUS_EXPR)
4147     return fold_convert (TREE_TYPE (expr), TREE_OPERAND (expr, 0));
4148
4149   return fold (expr);
4150 }
4151
4152 /* Returns true if a cast to TYPE may appear in an integral constant
4153    expression.  */
4154
4155 bool
4156 cast_valid_in_integral_constant_expression_p (tree type)
4157 {
4158   return (INTEGRAL_OR_ENUMERATION_TYPE_P (type)
4159           || cxx_dialect >= cxx11
4160           || dependent_type_p (type)
4161           || type == error_mark_node);
4162 }
4163
4164 /* Return true if we need to fix linkage information of DECL.  */
4165
4166 static bool
4167 cp_fix_function_decl_p (tree decl)
4168 {
4169   /* Skip if DECL is not externally visible.  */
4170   if (!TREE_PUBLIC (decl))
4171     return false;
4172
4173   /* We need to fix DECL if it a appears to be exported but with no
4174      function body.  Thunks do not have CFGs and we may need to
4175      handle them specially later.   */
4176   if (!gimple_has_body_p (decl)
4177       && !DECL_THUNK_P (decl)
4178       && !DECL_EXTERNAL (decl))
4179     {
4180       struct cgraph_node *node = cgraph_node::get (decl);
4181
4182       /* Don't fix same_body aliases.  Although they don't have their own
4183          CFG, they share it with what they alias to.  */
4184       if (!node || !node->alias
4185           || !vec_safe_length (node->ref_list.references))
4186         return true;
4187     }
4188
4189   return false;
4190 }
4191
4192 /* Clean the C++ specific parts of the tree T. */
4193
4194 void
4195 cp_free_lang_data (tree t)
4196 {
4197   if (TREE_CODE (t) == METHOD_TYPE
4198       || TREE_CODE (t) == FUNCTION_TYPE)
4199     {
4200       /* Default args are not interesting anymore.  */
4201       tree argtypes = TYPE_ARG_TYPES (t);
4202       while (argtypes)
4203         {
4204           TREE_PURPOSE (argtypes) = 0;
4205           argtypes = TREE_CHAIN (argtypes);
4206         }
4207     }
4208   else if (TREE_CODE (t) == FUNCTION_DECL
4209            && cp_fix_function_decl_p (t))
4210     {
4211       /* If T is used in this translation unit at all,  the definition
4212          must exist somewhere else since we have decided to not emit it
4213          in this TU.  So make it an external reference.  */
4214       DECL_EXTERNAL (t) = 1;
4215       TREE_STATIC (t) = 0;
4216     }
4217   if (TREE_CODE (t) == NAMESPACE_DECL)
4218     {
4219       /* The list of users of a namespace isn't useful for the middle-end
4220          or debug generators.  */
4221       DECL_NAMESPACE_USERS (t) = NULL_TREE;
4222       /* Neither do we need the leftover chaining of namespaces
4223          from the binding level.  */
4224       DECL_CHAIN (t) = NULL_TREE;
4225     }
4226 }
4227
4228 /* Stub for c-common.  Please keep in sync with c-decl.c.
4229    FIXME: If address space support is target specific, then this
4230    should be a C target hook.  But currently this is not possible,
4231    because this function is called via REGISTER_TARGET_PRAGMAS.  */
4232 void
4233 c_register_addr_space (const char * /*word*/, addr_space_t /*as*/)
4234 {
4235 }
4236
4237 /* Return the number of operands in T that we care about for things like
4238    mangling.  */
4239
4240 int
4241 cp_tree_operand_length (const_tree t)
4242 {
4243   enum tree_code code = TREE_CODE (t);
4244
4245   switch (code)
4246     {
4247     case PREINCREMENT_EXPR:
4248     case PREDECREMENT_EXPR:
4249     case POSTINCREMENT_EXPR:
4250     case POSTDECREMENT_EXPR:
4251       return 1;
4252
4253     case ARRAY_REF:
4254       return 2;
4255
4256     case EXPR_PACK_EXPANSION:
4257       return 1;
4258
4259     default:
4260       return TREE_OPERAND_LENGTH (t);
4261     }
4262 }
4263
4264 /* Implement -Wzero_as_null_pointer_constant.  Return true if the
4265    conditions for the warning hold, false otherwise.  */
4266 bool
4267 maybe_warn_zero_as_null_pointer_constant (tree expr, location_t loc)
4268 {
4269   if (c_inhibit_evaluation_warnings == 0
4270       && !NULLPTR_TYPE_P (TREE_TYPE (expr)))
4271     {
4272       warning_at (loc, OPT_Wzero_as_null_pointer_constant,
4273                   "zero as null pointer constant");
4274       return true;
4275     }
4276   return false;
4277 }
4278 \f
4279 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4280 /* Complain that some language-specific thing hanging off a tree
4281    node has been accessed improperly.  */
4282
4283 void
4284 lang_check_failed (const char* file, int line, const char* function)
4285 {
4286   internal_error ("lang_* check: failed in %s, at %s:%d",
4287                   function, trim_filename (file), line);
4288 }
4289 #endif /* ENABLE_TREE_CHECKING */
4290
4291 #include "gt-cp-tree.h"