gcc/cp/tree.c

   1 /* Language-dependent node constructors for parse phase of GNU compiler.
   2    Copyright (C) 1987-2017 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 "tree.h"
  25 #include "cp-tree.h"
  26 #include "gimple-expr.h"
  27 #include "cgraph.h"
  28 #include "stor-layout.h"
  29 #include "print-tree.h"
  30 #include "tree-iterator.h"
  31 #include "tree-inline.h"
  32 #include "debug.h"
  33 #include "convert.h"
  34 #include "gimplify.h"
  35 #include "attribs.h"
  36
  37 static tree bot_manip (tree *, int *, void *);
  38 static tree bot_replace (tree *, int *, void *);
  39 static hashval_t list_hash_pieces (tree, tree, tree);
  40 static tree build_target_expr (tree, tree, tsubst_flags_t);
  41 static tree count_trees_r (tree *, int *, void *);
  42 static tree verify_stmt_tree_r (tree *, int *, void *);
  43 static tree build_local_temp (tree);
  44
  45 static tree handle_init_priority_attribute (tree *, tree, tree, int, bool *);
  46 static tree handle_abi_tag_attribute (tree *, tree, tree, int, bool *);
  47
  48 /* If REF is an lvalue, returns the kind of lvalue that REF is.
  49    Otherwise, returns clk_none.  */
  50
  51 cp_lvalue_kind
  52 lvalue_kind (const_tree ref)
  53 {
  54   cp_lvalue_kind op1_lvalue_kind = clk_none;
  55   cp_lvalue_kind op2_lvalue_kind = clk_none;
  56
  57   /* Expressions of reference type are sometimes wrapped in
  58      INDIRECT_REFs.  INDIRECT_REFs are just internal compiler
  59      representation, not part of the language, so we have to look
  60      through them.  */
  61   if (REFERENCE_REF_P (ref))
  62     return lvalue_kind (TREE_OPERAND (ref, 0));
  63
  64   if (TREE_TYPE (ref)
  65       && TREE_CODE (TREE_TYPE (ref)) == REFERENCE_TYPE)
  66     {
  67       /* unnamed rvalue references are rvalues */
  68       if (TYPE_REF_IS_RVALUE (TREE_TYPE (ref))
  69           && TREE_CODE (ref) != PARM_DECL
  70           && !VAR_P (ref)
  71           && TREE_CODE (ref) != COMPONENT_REF
  72           /* Functions are always lvalues.  */
  73           && TREE_CODE (TREE_TYPE (TREE_TYPE (ref))) != FUNCTION_TYPE)
  74         return clk_rvalueref;
  75
  76       /* lvalue references and named rvalue references are lvalues.  */
  77       return clk_ordinary;
  78     }
  79
  80   if (ref == current_class_ptr)
  81     return clk_none;
  82
  83   switch (TREE_CODE (ref))
  84     {
  85     case SAVE_EXPR:
  86       return clk_none;
  87       /* preincrements and predecrements are valid lvals, provided
  88          what they refer to are valid lvals.  */
  89     case PREINCREMENT_EXPR:
  90     case PREDECREMENT_EXPR:
  91     case TRY_CATCH_EXPR:
  92     case WITH_CLEANUP_EXPR:
  93     case REALPART_EXPR:
  94     case IMAGPART_EXPR:
  95       return lvalue_kind (TREE_OPERAND (ref, 0));
  96
  97     case MEMBER_REF:
  98     case DOTSTAR_EXPR:
  99       if (TREE_CODE (ref) == MEMBER_REF)
 100         op1_lvalue_kind = clk_ordinary;
 101       else
 102         op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 0));
 103       if (TYPE_PTRMEMFUNC_P (TREE_TYPE (TREE_OPERAND (ref, 1))))
 104         op1_lvalue_kind = clk_none;
 105       return op1_lvalue_kind;
 106
 107     case COMPONENT_REF:
 108       op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 0));
 109       /* Look at the member designator.  */
 110       if (!op1_lvalue_kind)
 111         ;
 112       else if (is_overloaded_fn (TREE_OPERAND (ref, 1)))
 113         /* The "field" can be a FUNCTION_DECL or an OVERLOAD in some
 114            situations.  If we're seeing a COMPONENT_REF, it's a non-static
 115            member, so it isn't an lvalue. */
 116         op1_lvalue_kind = clk_none;
 117       else if (TREE_CODE (TREE_OPERAND (ref, 1)) != FIELD_DECL)
 118         /* This can be IDENTIFIER_NODE in a template.  */;
 119       else if (DECL_C_BIT_FIELD (TREE_OPERAND (ref, 1)))
 120         {
 121           /* Clear the ordinary bit.  If this object was a class
 122              rvalue we want to preserve that information.  */
 123           op1_lvalue_kind &= ~clk_ordinary;
 124           /* The lvalue is for a bitfield.  */
 125           op1_lvalue_kind |= clk_bitfield;
 126         }
 127       else if (DECL_PACKED (TREE_OPERAND (ref, 1)))
 128         op1_lvalue_kind |= clk_packed;
 129
 130       return op1_lvalue_kind;
 131
 132     case STRING_CST:
 133     case COMPOUND_LITERAL_EXPR:
 134       return clk_ordinary;
 135
 136     case CONST_DECL:
 137       /* CONST_DECL without TREE_STATIC are enumeration values and
 138          thus not lvalues.  With TREE_STATIC they are used by ObjC++
 139          in objc_build_string_object and need to be considered as
 140          lvalues.  */
 141       if (! TREE_STATIC (ref))
 142         return clk_none;
 143       /* FALLTHRU */
 144     case VAR_DECL:
 145       if (VAR_P (ref) && DECL_HAS_VALUE_EXPR_P (ref))
 146         return lvalue_kind (DECL_VALUE_EXPR (CONST_CAST_TREE (ref)));
 147
 148       if (TREE_READONLY (ref) && ! TREE_STATIC (ref)
 149           && DECL_LANG_SPECIFIC (ref)
 150           && DECL_IN_AGGR_P (ref))
 151         return clk_none;
 152       /* FALLTHRU */
 153     case INDIRECT_REF:
 154     case ARROW_EXPR:
 155     case ARRAY_REF:
 156     case ARRAY_NOTATION_REF:
 157     case PARM_DECL:
 158     case RESULT_DECL:
 159     case PLACEHOLDER_EXPR:
 160       return clk_ordinary;
 161
 162       /* A scope ref in a template, left as SCOPE_REF to support later
 163          access checking.  */
 164     case SCOPE_REF:
 165       gcc_assert (!type_dependent_expression_p (CONST_CAST_TREE (ref)));
 166       {
 167         tree op = TREE_OPERAND (ref, 1);
 168         if (TREE_CODE (op) == FIELD_DECL)
 169           return (DECL_C_BIT_FIELD (op) ? clk_bitfield : clk_ordinary);
 170         else
 171           return lvalue_kind (op);
 172       }
 173
 174     case MAX_EXPR:
 175     case MIN_EXPR:
 176       /* Disallow <? and >? as lvalues if either argument side-effects.  */
 177       if (TREE_SIDE_EFFECTS (TREE_OPERAND (ref, 0))
 178           || TREE_SIDE_EFFECTS (TREE_OPERAND (ref, 1)))
 179         return clk_none;
 180       op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 0));
 181       op2_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 1));
 182       break;
 183
 184     case COND_EXPR:
 185       op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 1)
 186                                     ? TREE_OPERAND (ref, 1)
 187                                     : TREE_OPERAND (ref, 0));
 188       op2_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 2));
 189       break;
 190
 191     case MODOP_EXPR:
 192       /* We expect to see unlowered MODOP_EXPRs only during
 193          template processing.  */
 194       gcc_assert (processing_template_decl);
 195       return clk_ordinary;
 196
 197     case MODIFY_EXPR:
 198     case TYPEID_EXPR:
 199       return clk_ordinary;
 200
 201     case COMPOUND_EXPR:
 202       return lvalue_kind (TREE_OPERAND (ref, 1));
 203
 204     case TARGET_EXPR:
 205       return clk_class;
 206
 207     case VA_ARG_EXPR:
 208       return (CLASS_TYPE_P (TREE_TYPE (ref)) ? clk_class : clk_none);
 209
 210     case CALL_EXPR:
 211       /* We can see calls outside of TARGET_EXPR in templates.  */
 212       if (CLASS_TYPE_P (TREE_TYPE (ref)))
 213         return clk_class;
 214       return clk_none;
 215
 216     case FUNCTION_DECL:
 217       /* All functions (except non-static-member functions) are
 218          lvalues.  */
 219       return (DECL_NONSTATIC_MEMBER_FUNCTION_P (ref)
 220               ? clk_none : clk_ordinary);
 221
 222     case BASELINK:
 223       /* We now represent a reference to a single static member function
 224          with a BASELINK.  */
 225       /* This CONST_CAST is okay because BASELINK_FUNCTIONS returns
 226          its argument unmodified and we assign it to a const_tree.  */
 227       return lvalue_kind (BASELINK_FUNCTIONS (CONST_CAST_TREE (ref)));
 228
 229     case NON_DEPENDENT_EXPR:
 230       return lvalue_kind (TREE_OPERAND (ref, 0));
 231
 232     default:
 233       if (!TREE_TYPE (ref))
 234         return clk_none;
 235       if (CLASS_TYPE_P (TREE_TYPE (ref)))
 236         return clk_class;
 237       break;
 238     }
 239
 240   /* If one operand is not an lvalue at all, then this expression is
 241      not an lvalue.  */
 242   if (!op1_lvalue_kind || !op2_lvalue_kind)
 243     return clk_none;
 244
 245   /* Otherwise, it's an lvalue, and it has all the odd properties
 246      contributed by either operand.  */
 247   op1_lvalue_kind = op1_lvalue_kind | op2_lvalue_kind;
 248   /* It's not an ordinary lvalue if it involves any other kind.  */
 249   if ((op1_lvalue_kind & ~clk_ordinary) != clk_none)
 250     op1_lvalue_kind &= ~clk_ordinary;
 251   /* It can't be both a pseudo-lvalue and a non-addressable lvalue.
 252      A COND_EXPR of those should be wrapped in a TARGET_EXPR.  */
 253   if ((op1_lvalue_kind & (clk_rvalueref|clk_class))
 254       && (op1_lvalue_kind & (clk_bitfield|clk_packed)))
 255     op1_lvalue_kind = clk_none;
 256   return op1_lvalue_kind;
 257 }
 258
 259 /* Returns the kind of lvalue that REF is, in the sense of [basic.lval].  */
 260
 261 cp_lvalue_kind
 262 real_lvalue_p (const_tree ref)
 263 {
 264   cp_lvalue_kind kind = lvalue_kind (ref);
 265   if (kind & (clk_rvalueref|clk_class))
 266     return clk_none;
 267   else
 268     return kind;
 269 }
 270
 271 /* c-common wants us to return bool.  */
 272
 273 bool
 274 lvalue_p (const_tree t)
 275 {
 276   return real_lvalue_p (t);
 277 }
 278
 279 /* This differs from lvalue_p in that xvalues are included.  */
 280
 281 bool
 282 glvalue_p (const_tree ref)
 283 {
 284   cp_lvalue_kind kind = lvalue_kind (ref);
 285   if (kind & clk_class)
 286     return false;
 287   else
 288     return (kind != clk_none);
 289 }
 290
 291 /* This differs from glvalue_p in that class prvalues are included.  */
 292
 293 bool
 294 obvalue_p (const_tree ref)
 295 {
 296   return (lvalue_kind (ref) != clk_none);
 297 }
 298
 299 /* Returns true if REF is an xvalue (the result of dereferencing an rvalue
 300    reference), false otherwise.  */
 301
 302 bool
 303 xvalue_p (const_tree ref)
 304 {
 305   return (lvalue_kind (ref) == clk_rvalueref);
 306 }
 307
 308 /* True if REF is a bit-field.  */
 309
 310 bool
 311 bitfield_p (const_tree ref)
 312 {
 313   return (lvalue_kind (ref) & clk_bitfield);
 314 }
 315
 316 /* C++-specific version of stabilize_reference.  */
 317
 318 tree
 319 cp_stabilize_reference (tree ref)
 320 {
 321   switch (TREE_CODE (ref))
 322     {
 323     /* We need to treat specially anything stabilize_reference doesn't
 324        handle specifically.  */
 325     case VAR_DECL:
 326     case PARM_DECL:
 327     case RESULT_DECL:
 328     CASE_CONVERT:
 329     case FLOAT_EXPR:
 330     case FIX_TRUNC_EXPR:
 331     case INDIRECT_REF:
 332     case COMPONENT_REF:
 333     case BIT_FIELD_REF:
 334     case ARRAY_REF:
 335     case ARRAY_RANGE_REF:
 336     case ERROR_MARK:
 337       break;
 338     default:
 339       cp_lvalue_kind kind = lvalue_kind (ref);
 340       if ((kind & ~clk_class) != clk_none)
 341         {
 342           tree type = unlowered_expr_type (ref);
 343           bool rval = !!(kind & clk_rvalueref);
 344           type = cp_build_reference_type (type, rval);
 345           /* This inhibits warnings in, eg, cxx_mark_addressable
 346              (c++/60955).  */
 347           warning_sentinel s (extra_warnings);
 348           ref = build_static_cast (type, ref, tf_error);
 349         }
 350     }
 351
 352   return stabilize_reference (ref);
 353 }
 354
 355 /* Test whether DECL is a builtin that may appear in a
 356    constant-expression. */
 357
 358 bool
 359 builtin_valid_in_constant_expr_p (const_tree decl)
 360 {
 361   if (!(TREE_CODE (decl) == FUNCTION_DECL
 362         && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL))
 363     /* Not a built-in.  */
 364     return false;
 365   switch (DECL_FUNCTION_CODE (decl))
 366     {
 367       /* These always have constant results like the corresponding
 368          macros/symbol.  */
 369     case BUILT_IN_FILE:
 370     case BUILT_IN_FUNCTION:
 371     case BUILT_IN_LINE:
 372
 373       /* The following built-ins are valid in constant expressions
 374          when their arguments are.  */
 375     case BUILT_IN_ADD_OVERFLOW_P:
 376     case BUILT_IN_SUB_OVERFLOW_P:
 377     case BUILT_IN_MUL_OVERFLOW_P:
 378
 379       /* These have constant results even if their operands are
 380          non-constant.  */
 381     case BUILT_IN_CONSTANT_P:
 382     case BUILT_IN_ATOMIC_ALWAYS_LOCK_FREE:
 383       return true;
 384     default:
 385       return false;
 386     }
 387 }
 388
 389 /* Build a TARGET_EXPR, initializing the DECL with the VALUE.  */
 390
 391 static tree
 392 build_target_expr (tree decl, tree value, tsubst_flags_t complain)
 393 {
 394   tree t;
 395   tree type = TREE_TYPE (decl);
 396
 397   value = mark_rvalue_use (value);
 398
 399   gcc_checking_assert (VOID_TYPE_P (TREE_TYPE (value))
 400                        || TREE_TYPE (decl) == TREE_TYPE (value)
 401                        /* On ARM ctors return 'this'.  */
 402                        || (TYPE_PTR_P (TREE_TYPE (value))
 403                            && TREE_CODE (value) == CALL_EXPR)
 404                        || useless_type_conversion_p (TREE_TYPE (decl),
 405                                                      TREE_TYPE (value)));
 406
 407   if (complain & tf_no_cleanup)
 408     /* The caller is building a new-expr and does not need a cleanup.  */
 409     t = NULL_TREE;
 410   else
 411     {
 412       t = cxx_maybe_build_cleanup (decl, complain);
 413       if (t == error_mark_node)
 414         return error_mark_node;
 415     }
 416   t = build4 (TARGET_EXPR, type, decl, value, t, NULL_TREE);
 417   if (EXPR_HAS_LOCATION (value))
 418     SET_EXPR_LOCATION (t, EXPR_LOCATION (value));
 419   /* We always set TREE_SIDE_EFFECTS so that expand_expr does not
 420      ignore the TARGET_EXPR.  If there really turn out to be no
 421      side-effects, then the optimizer should be able to get rid of
 422      whatever code is generated anyhow.  */
 423   TREE_SIDE_EFFECTS (t) = 1;
 424
 425   return t;
 426 }
 427
 428 /* Return an undeclared local temporary of type TYPE for use in building a
 429    TARGET_EXPR.  */
 430
 431 static tree
 432 build_local_temp (tree type)
 433 {
 434   tree slot = build_decl (input_location,
 435                           VAR_DECL, NULL_TREE, type);
 436   DECL_ARTIFICIAL (slot) = 1;
 437   DECL_IGNORED_P (slot) = 1;
 438   DECL_CONTEXT (slot) = current_function_decl;
 439   layout_decl (slot, 0);
 440   return slot;
 441 }
 442
 443 /* Set various status flags when building an AGGR_INIT_EXPR object T.  */
 444
 445 static void
 446 process_aggr_init_operands (tree t)
 447 {
 448   bool side_effects;
 449
 450   side_effects = TREE_SIDE_EFFECTS (t);
 451   if (!side_effects)
 452     {
 453       int i, n;
 454       n = TREE_OPERAND_LENGTH (t);
 455       for (i = 1; i < n; i++)
 456         {
 457           tree op = TREE_OPERAND (t, i);
 458           if (op && TREE_SIDE_EFFECTS (op))
 459             {
 460               side_effects = 1;
 461               break;
 462             }
 463         }
 464     }
 465   TREE_SIDE_EFFECTS (t) = side_effects;
 466 }
 467
 468 /* Build an AGGR_INIT_EXPR of class tcc_vl_exp with the indicated RETURN_TYPE,
 469    FN, and SLOT.  NARGS is the number of call arguments which are specified
 470    as a tree array ARGS.  */
 471
 472 static tree
 473 build_aggr_init_array (tree return_type, tree fn, tree slot, int nargs,
 474                        tree *args)
 475 {
 476   tree t;
 477   int i;
 478
 479   t = build_vl_exp (AGGR_INIT_EXPR, nargs + 3);
 480   TREE_TYPE (t) = return_type;
 481   AGGR_INIT_EXPR_FN (t) = fn;
 482   AGGR_INIT_EXPR_SLOT (t) = slot;
 483   for (i = 0; i < nargs; i++)
 484     AGGR_INIT_EXPR_ARG (t, i) = args[i];
 485   process_aggr_init_operands (t);
 486   return t;
 487 }
 488
 489 /* INIT is a CALL_EXPR or AGGR_INIT_EXPR which needs info about its
 490    target.  TYPE is the type to be initialized.
 491
 492    Build an AGGR_INIT_EXPR to represent the initialization.  This function
 493    differs from build_cplus_new in that an AGGR_INIT_EXPR can only be used
 494    to initialize another object, whereas a TARGET_EXPR can either
 495    initialize another object or create its own temporary object, and as a
 496    result building up a TARGET_EXPR requires that the type's destructor be
 497    callable.  */
 498
 499 tree
 500 build_aggr_init_expr (tree type, tree init)
 501 {
 502   tree fn;
 503   tree slot;
 504   tree rval;
 505   int is_ctor;
 506
 507   /* Don't build AGGR_INIT_EXPR in a template.  */
 508   if (processing_template_decl)
 509     return init;
 510
 511   fn = cp_get_callee (init);
 512   if (fn == NULL_TREE)
 513     return convert (type, init);
 514
 515   is_ctor = (TREE_CODE (fn) == ADDR_EXPR
 516              && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
 517              && DECL_CONSTRUCTOR_P (TREE_OPERAND (fn, 0)));
 518
 519   /* We split the CALL_EXPR into its function and its arguments here.
 520      Then, in expand_expr, we put them back together.  The reason for
 521      this is that this expression might be a default argument
 522      expression.  In that case, we need a new temporary every time the
 523      expression is used.  That's what break_out_target_exprs does; it
 524      replaces every AGGR_INIT_EXPR with a copy that uses a fresh
 525      temporary slot.  Then, expand_expr builds up a call-expression
 526      using the new slot.  */
 527
 528   /* If we don't need to use a constructor to create an object of this
 529      type, don't mess with AGGR_INIT_EXPR.  */
 530   if (is_ctor || TREE_ADDRESSABLE (type))
 531     {
 532       slot = build_local_temp (type);
 533
 534       if (TREE_CODE (init) == CALL_EXPR)
 535         {
 536           rval = build_aggr_init_array (void_type_node, fn, slot,
 537                                         call_expr_nargs (init),
 538                                         CALL_EXPR_ARGP (init));
 539           AGGR_INIT_FROM_THUNK_P (rval)
 540             = CALL_FROM_THUNK_P (init);
 541         }
 542       else
 543         {
 544           rval = build_aggr_init_array (void_type_node, fn, slot,
 545                                         aggr_init_expr_nargs (init),
 546                                         AGGR_INIT_EXPR_ARGP (init));
 547           AGGR_INIT_FROM_THUNK_P (rval)
 548             = AGGR_INIT_FROM_THUNK_P (init);
 549         }
 550       TREE_SIDE_EFFECTS (rval) = 1;
 551       AGGR_INIT_VIA_CTOR_P (rval) = is_ctor;
 552       TREE_NOTHROW (rval) = TREE_NOTHROW (init);
 553       CALL_EXPR_OPERATOR_SYNTAX (rval) = CALL_EXPR_OPERATOR_SYNTAX (init);
 554       CALL_EXPR_ORDERED_ARGS (rval) = CALL_EXPR_ORDERED_ARGS (init);
 555       CALL_EXPR_REVERSE_ARGS (rval) = CALL_EXPR_REVERSE_ARGS (init);
 556     }
 557   else
 558     rval = init;
 559
 560   return rval;
 561 }
 562
 563 /* INIT is a CALL_EXPR or AGGR_INIT_EXPR which needs info about its
 564    target.  TYPE is the type that this initialization should appear to
 565    have.
 566
 567    Build an encapsulation of the initialization to perform
 568    and return it so that it can be processed by language-independent
 569    and language-specific expression expanders.  */
 570
 571 tree
 572 build_cplus_new (tree type, tree init, tsubst_flags_t complain)
 573 {
 574   tree rval = build_aggr_init_expr (type, init);
 575   tree slot;
 576
 577   if (!complete_type_or_maybe_complain (type, init, complain))
 578     return error_mark_node;
 579
 580   /* Make sure that we're not trying to create an instance of an
 581      abstract class.  */
 582   if (abstract_virtuals_error_sfinae (NULL_TREE, type, complain))
 583     return error_mark_node;
 584
 585   if (TREE_CODE (rval) == AGGR_INIT_EXPR)
 586     slot = AGGR_INIT_EXPR_SLOT (rval);
 587   else if (TREE_CODE (rval) == CALL_EXPR
 588            || TREE_CODE (rval) == CONSTRUCTOR)
 589     slot = build_local_temp (type);
 590   else
 591     return rval;
 592
 593   rval = build_target_expr (slot, rval, complain);
 594
 595   if (rval != error_mark_node)
 596     TARGET_EXPR_IMPLICIT_P (rval) = 1;
 597
 598   return rval;
 599 }
 600
 601 /* Subroutine of build_vec_init_expr: Build up a single element
 602    intialization as a proxy for the full array initialization to get things
 603    marked as used and any appropriate diagnostics.
 604
 605    Since we're deferring building the actual constructor calls until
 606    gimplification time, we need to build one now and throw it away so
 607    that the relevant constructor gets mark_used before cgraph decides
 608    what functions are needed.  Here we assume that init is either
 609    NULL_TREE, void_type_node (indicating value-initialization), or
 610    another array to copy.  */
 611
 612 static tree
 613 build_vec_init_elt (tree type, tree init, tsubst_flags_t complain)
 614 {
 615   tree inner_type = strip_array_types (type);
 616   vec<tree, va_gc> *argvec;
 617
 618   if (integer_zerop (array_type_nelts_total (type))
 619       || !CLASS_TYPE_P (inner_type))
 620     /* No interesting initialization to do.  */
 621     return integer_zero_node;
 622   else if (init == void_type_node)
 623     return build_value_init (inner_type, complain);
 624
 625   gcc_assert (init == NULL_TREE
 626               || (same_type_ignoring_top_level_qualifiers_p
 627                   (type, TREE_TYPE (init))));
 628
 629   argvec = make_tree_vector ();
 630   if (init)
 631     {
 632       tree init_type = strip_array_types (TREE_TYPE (init));
 633       tree dummy = build_dummy_object (init_type);
 634       if (!lvalue_p (init))
 635         dummy = move (dummy);
 636       argvec->quick_push (dummy);
 637     }
 638   init = build_special_member_call (NULL_TREE, complete_ctor_identifier,
 639                                     &argvec, inner_type, LOOKUP_NORMAL,
 640                                     complain);
 641   release_tree_vector (argvec);
 642
 643   /* For a trivial constructor, build_over_call creates a TARGET_EXPR.  But
 644      we don't want one here because we aren't creating a temporary.  */
 645   if (TREE_CODE (init) == TARGET_EXPR)
 646     init = TARGET_EXPR_INITIAL (init);
 647
 648   return init;
 649 }
 650
 651 /* Return a TARGET_EXPR which expresses the initialization of an array to
 652    be named later, either default-initialization or copy-initialization
 653    from another array of the same type.  */
 654
 655 tree
 656 build_vec_init_expr (tree type, tree init, tsubst_flags_t complain)
 657 {
 658   tree slot;
 659   bool value_init = false;
 660   tree elt_init = build_vec_init_elt (type, init, complain);
 661
 662   if (init == void_type_node)
 663     {
 664       value_init = true;
 665       init = NULL_TREE;
 666     }
 667
 668   slot = build_local_temp (type);
 669   init = build2 (VEC_INIT_EXPR, type, slot, init);
 670   TREE_SIDE_EFFECTS (init) = true;
 671   SET_EXPR_LOCATION (init, input_location);
 672
 673   if (cxx_dialect >= cxx11
 674       && potential_constant_expression (elt_init))
 675     VEC_INIT_EXPR_IS_CONSTEXPR (init) = true;
 676   VEC_INIT_EXPR_VALUE_INIT (init) = value_init;
 677
 678   return init;
 679 }
 680
 681 /* Give a helpful diagnostic for a non-constexpr VEC_INIT_EXPR in a context
 682    that requires a constant expression.  */
 683
 684 void
 685 diagnose_non_constexpr_vec_init (tree expr)
 686 {
 687   tree type = TREE_TYPE (VEC_INIT_EXPR_SLOT (expr));
 688   tree init, elt_init;
 689   if (VEC_INIT_EXPR_VALUE_INIT (expr))
 690     init = void_type_node;
 691   else
 692     init = VEC_INIT_EXPR_INIT (expr);
 693
 694   elt_init = build_vec_init_elt (type, init, tf_warning_or_error);
 695   require_potential_constant_expression (elt_init);
 696 }
 697
 698 tree
 699 build_array_copy (tree init)
 700 {
 701   return build_vec_init_expr (TREE_TYPE (init), init, tf_warning_or_error);
 702 }
 703
 704 /* Build a TARGET_EXPR using INIT to initialize a new temporary of the
 705    indicated TYPE.  */
 706
 707 tree
 708 build_target_expr_with_type (tree init, tree type, tsubst_flags_t complain)
 709 {
 710   gcc_assert (!VOID_TYPE_P (type));
 711
 712   if (TREE_CODE (init) == TARGET_EXPR
 713       || init == error_mark_node)
 714     return init;
 715   else if (CLASS_TYPE_P (type) && type_has_nontrivial_copy_init (type)
 716            && !VOID_TYPE_P (TREE_TYPE (init))
 717            && TREE_CODE (init) != COND_EXPR
 718            && TREE_CODE (init) != CONSTRUCTOR
 719            && TREE_CODE (init) != VA_ARG_EXPR)
 720     /* We need to build up a copy constructor call.  A void initializer
 721        means we're being called from bot_manip.  COND_EXPR is a special
 722        case because we already have copies on the arms and we don't want
 723        another one here.  A CONSTRUCTOR is aggregate initialization, which
 724        is handled separately.  A VA_ARG_EXPR is magic creation of an
 725        aggregate; there's no additional work to be done.  */
 726     return force_rvalue (init, complain);
 727
 728   return force_target_expr (type, init, complain);
 729 }
 730
 731 /* Like the above function, but without the checking.  This function should
 732    only be used by code which is deliberately trying to subvert the type
 733    system, such as call_builtin_trap.  Or build_over_call, to avoid
 734    infinite recursion.  */
 735
 736 tree
 737 force_target_expr (tree type, tree init, tsubst_flags_t complain)
 738 {
 739   tree slot;
 740
 741   gcc_assert (!VOID_TYPE_P (type));
 742
 743   slot = build_local_temp (type);
 744   return build_target_expr (slot, init, complain);
 745 }
 746
 747 /* Like build_target_expr_with_type, but use the type of INIT.  */
 748
 749 tree
 750 get_target_expr_sfinae (tree init, tsubst_flags_t complain)
 751 {
 752   if (TREE_CODE (init) == AGGR_INIT_EXPR)
 753     return build_target_expr (AGGR_INIT_EXPR_SLOT (init), init, complain);
 754   else if (TREE_CODE (init) == VEC_INIT_EXPR)
 755     return build_target_expr (VEC_INIT_EXPR_SLOT (init), init, complain);
 756   else
 757     {
 758       init = convert_bitfield_to_declared_type (init);
 759       return build_target_expr_with_type (init, TREE_TYPE (init), complain);
 760     }
 761 }
 762
 763 tree
 764 get_target_expr (tree init)
 765 {
 766   return get_target_expr_sfinae (init, tf_warning_or_error);
 767 }
 768
 769 /* If EXPR is a bitfield reference, convert it to the declared type of
 770    the bitfield, and return the resulting expression.  Otherwise,
 771    return EXPR itself.  */
 772
 773 tree
 774 convert_bitfield_to_declared_type (tree expr)
 775 {
 776   tree bitfield_type;
 777
 778   bitfield_type = is_bitfield_expr_with_lowered_type (expr);
 779   if (bitfield_type)
 780     expr = convert_to_integer_nofold (TYPE_MAIN_VARIANT (bitfield_type),
 781                                       expr);
 782   return expr;
 783 }
 784
 785 /* EXPR is being used in an rvalue context.  Return a version of EXPR
 786    that is marked as an rvalue.  */
 787
 788 tree
 789 rvalue (tree expr)
 790 {
 791   tree type;
 792
 793   if (error_operand_p (expr))
 794     return expr;
 795
 796   expr = mark_rvalue_use (expr);
 797
 798   /* [basic.lval]
 799
 800      Non-class rvalues always have cv-unqualified types.  */
 801   type = TREE_TYPE (expr);
 802   if (!CLASS_TYPE_P (type) && cv_qualified_p (type))
 803     type = cv_unqualified (type);
 804
 805   /* We need to do this for rvalue refs as well to get the right answer
 806      from decltype; see c++/36628.  */
 807   if (!processing_template_decl && glvalue_p (expr))
 808     expr = build1 (NON_LVALUE_EXPR, type, expr);
 809   else if (type != TREE_TYPE (expr))
 810     expr = build_nop (type, expr);
 811
 812   return expr;
 813 }
 814
 815 \f
 816 struct cplus_array_info
 817 {
 818   tree type;
 819   tree domain;
 820 };
 821
 822 struct cplus_array_hasher : ggc_ptr_hash<tree_node>
 823 {
 824   typedef cplus_array_info *compare_type;
 825
 826   static hashval_t hash (tree t);
 827   static bool equal (tree, cplus_array_info *);
 828 };
 829
 830 /* Hash an ARRAY_TYPE.  K is really of type `tree'.  */
 831
 832 hashval_t
 833 cplus_array_hasher::hash (tree t)
 834 {
 835   hashval_t hash;
 836
 837   hash = TYPE_UID (TREE_TYPE (t));
 838   if (TYPE_DOMAIN (t))
 839     hash ^= TYPE_UID (TYPE_DOMAIN (t));
 840   return hash;
 841 }
 842
 843 /* Compare two ARRAY_TYPEs.  K1 is really of type `tree', K2 is really
 844    of type `cplus_array_info*'. */
 845
 846 bool
 847 cplus_array_hasher::equal (tree t1, cplus_array_info *t2)
 848 {
 849   return (TREE_TYPE (t1) == t2->type && TYPE_DOMAIN (t1) == t2->domain);
 850 }
 851
 852 /* Hash table containing dependent array types, which are unsuitable for
 853    the language-independent type hash table.  */
 854 static GTY (()) hash_table<cplus_array_hasher> *cplus_array_htab;
 855
 856 /* Build an ARRAY_TYPE without laying it out.  */
 857
 858 static tree
 859 build_min_array_type (tree elt_type, tree index_type)
 860 {
 861   tree t = cxx_make_type (ARRAY_TYPE);
 862   TREE_TYPE (t) = elt_type;
 863   TYPE_DOMAIN (t) = index_type;
 864   return t;
 865 }
 866
 867 /* Set TYPE_CANONICAL like build_array_type_1, but using
 868    build_cplus_array_type.  */
 869
 870 static void
 871 set_array_type_canon (tree t, tree elt_type, tree index_type)
 872 {
 873   /* Set the canonical type for this new node.  */
 874   if (TYPE_STRUCTURAL_EQUALITY_P (elt_type)
 875       || (index_type && TYPE_STRUCTURAL_EQUALITY_P (index_type)))
 876     SET_TYPE_STRUCTURAL_EQUALITY (t);
 877   else if (TYPE_CANONICAL (elt_type) != elt_type
 878            || (index_type && TYPE_CANONICAL (index_type) != index_type))
 879     TYPE_CANONICAL (t)
 880       = build_cplus_array_type (TYPE_CANONICAL (elt_type),
 881                                 index_type
 882                                 ? TYPE_CANONICAL (index_type) : index_type);
 883   else
 884     TYPE_CANONICAL (t) = t;
 885 }
 886
 887 /* Like build_array_type, but handle special C++ semantics: an array of a
 888    variant element type is a variant of the array of the main variant of
 889    the element type.  */
 890
 891 tree
 892 build_cplus_array_type (tree elt_type, tree index_type)
 893 {
 894   tree t;
 895
 896   if (elt_type == error_mark_node || index_type == error_mark_node)
 897     return error_mark_node;
 898
 899   bool dependent = (uses_template_parms (elt_type)
 900                     || (index_type && uses_template_parms (index_type)));
 901
 902   if (elt_type != TYPE_MAIN_VARIANT (elt_type))
 903     /* Start with an array of the TYPE_MAIN_VARIANT.  */
 904     t = build_cplus_array_type (TYPE_MAIN_VARIANT (elt_type),
 905                                 index_type);
 906   else if (dependent)
 907     {
 908       /* Since type_hash_canon calls layout_type, we need to use our own
 909          hash table.  */
 910       cplus_array_info cai;
 911       hashval_t hash;
 912
 913       if (cplus_array_htab == NULL)
 914         cplus_array_htab = hash_table<cplus_array_hasher>::create_ggc (61);
 915
 916       hash = TYPE_UID (elt_type);
 917       if (index_type)
 918         hash ^= TYPE_UID (index_type);
 919       cai.type = elt_type;
 920       cai.domain = index_type;
 921
 922       tree *e = cplus_array_htab->find_slot_with_hash (&cai, hash, INSERT);
 923       if (*e)
 924         /* We have found the type: we're done.  */
 925         return (tree) *e;
 926       else
 927         {
 928           /* Build a new array type.  */
 929           t = build_min_array_type (elt_type, index_type);
 930
 931           /* Store it in the hash table. */
 932           *e = t;
 933
 934           /* Set the canonical type for this new node.  */
 935           set_array_type_canon (t, elt_type, index_type);
 936         }
 937     }
 938   else
 939     {
 940       t = build_array_type (elt_type, index_type);
 941     }
 942
 943   /* Now check whether we already have this array variant.  */
 944   if (elt_type != TYPE_MAIN_VARIANT (elt_type))
 945     {
 946       tree m = t;
 947       for (t = m; t; t = TYPE_NEXT_VARIANT (t))
 948         if (TREE_TYPE (t) == elt_type
 949             && TYPE_NAME (t) == NULL_TREE
 950             && TYPE_ATTRIBUTES (t) == NULL_TREE)
 951           break;
 952       if (!t)
 953         {
 954           t = build_min_array_type (elt_type, index_type);
 955           set_array_type_canon (t, elt_type, index_type);
 956           if (!dependent)
 957             {
 958               layout_type (t);
 959               /* Make sure sizes are shared with the main variant.
 960                  layout_type can't be called after setting TYPE_NEXT_VARIANT,
 961                  as it will overwrite alignment etc. of all variants.  */
 962               TYPE_SIZE (t) = TYPE_SIZE (m);
 963               TYPE_SIZE_UNIT (t) = TYPE_SIZE_UNIT (m);
 964             }
 965
 966           TYPE_MAIN_VARIANT (t) = m;
 967           TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
 968           TYPE_NEXT_VARIANT (m) = t;
 969         }
 970     }
 971
 972   /* Avoid spurious warnings with VLAs (c++/54583).  */
 973   if (TYPE_SIZE (t) && EXPR_P (TYPE_SIZE (t)))
 974     TREE_NO_WARNING (TYPE_SIZE (t)) = 1;
 975
 976   /* Push these needs up to the ARRAY_TYPE so that initialization takes
 977      place more easily.  */
 978   bool needs_ctor = (TYPE_NEEDS_CONSTRUCTING (t)
 979                      = TYPE_NEEDS_CONSTRUCTING (elt_type));
 980   bool needs_dtor = (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
 981                      = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (elt_type));
 982
 983   if (!dependent && t == TYPE_MAIN_VARIANT (t)
 984       && !COMPLETE_TYPE_P (t) && COMPLETE_TYPE_P (elt_type))
 985     {
 986       /* The element type has been completed since the last time we saw
 987          this array type; update the layout and 'tor flags for any variants
 988          that need it.  */
 989       layout_type (t);
 990       for (tree v = TYPE_NEXT_VARIANT (t); v; v = TYPE_NEXT_VARIANT (v))
 991         {
 992           TYPE_NEEDS_CONSTRUCTING (v) = needs_ctor;
 993           TYPE_HAS_NONTRIVIAL_DESTRUCTOR (v) = needs_dtor;
 994         }
 995     }
 996
 997   return t;
 998 }
 999
1000 /* Return an ARRAY_TYPE with element type ELT and length N.  */
1001
1002 tree
1003 build_array_of_n_type (tree elt, int n)
1004 {
1005   return build_cplus_array_type (elt, build_index_type (size_int (n - 1)));
1006 }
1007
1008 /* True iff T is an N3639 array of runtime bound (VLA).  These were
1009    approved for C++14 but then removed.  */
1010
1011 bool
1012 array_of_runtime_bound_p (tree t)
1013 {
1014   if (!t || TREE_CODE (t) != ARRAY_TYPE)
1015     return false;
1016   tree dom = TYPE_DOMAIN (t);
1017   if (!dom)
1018     return false;
1019   tree max = TYPE_MAX_VALUE (dom);
1020   return (!potential_rvalue_constant_expression (max)
1021           || (!value_dependent_expression_p (max) && !TREE_CONSTANT (max)));
1022 }
1023
1024 /* Return a reference type node referring to TO_TYPE.  If RVAL is
1025    true, return an rvalue reference type, otherwise return an lvalue
1026    reference type.  If a type node exists, reuse it, otherwise create
1027    a new one.  */
1028 tree
1029 cp_build_reference_type (tree to_type, bool rval)
1030 {
1031   tree lvalue_ref, t;
1032
1033   if (TREE_CODE (to_type) == REFERENCE_TYPE)
1034     {
1035       rval = rval && TYPE_REF_IS_RVALUE (to_type);
1036       to_type = TREE_TYPE (to_type);
1037     }
1038
1039   lvalue_ref = build_reference_type (to_type);
1040   if (!rval)
1041     return lvalue_ref;
1042
1043   /* This code to create rvalue reference types is based on and tied
1044      to the code creating lvalue reference types in the middle-end
1045      functions build_reference_type_for_mode and build_reference_type.
1046
1047      It works by putting the rvalue reference type nodes after the
1048      lvalue reference nodes in the TYPE_NEXT_REF_TO linked list, so
1049      they will effectively be ignored by the middle end.  */
1050
1051   for (t = lvalue_ref; (t = TYPE_NEXT_REF_TO (t)); )
1052     if (TYPE_REF_IS_RVALUE (t))
1053       return t;
1054
1055   t = build_distinct_type_copy (lvalue_ref);
1056
1057   TYPE_REF_IS_RVALUE (t) = true;
1058   TYPE_NEXT_REF_TO (t) = TYPE_NEXT_REF_TO (lvalue_ref);
1059   TYPE_NEXT_REF_TO (lvalue_ref) = t;
1060
1061   if (TYPE_STRUCTURAL_EQUALITY_P (to_type))
1062     SET_TYPE_STRUCTURAL_EQUALITY (t);
1063   else if (TYPE_CANONICAL (to_type) != to_type)
1064     TYPE_CANONICAL (t)
1065       = cp_build_reference_type (TYPE_CANONICAL (to_type), rval);
1066   else
1067     TYPE_CANONICAL (t) = t;
1068
1069   layout_type (t);
1070
1071   return t;
1072
1073 }
1074
1075 /* Returns EXPR cast to rvalue reference type, like std::move.  */
1076
1077 tree
1078 move (tree expr)
1079 {
1080   tree type = TREE_TYPE (expr);
1081   gcc_assert (TREE_CODE (type) != REFERENCE_TYPE);
1082   type = cp_build_reference_type (type, /*rval*/true);
1083   return build_static_cast (type, expr, tf_warning_or_error);
1084 }
1085
1086 /* Used by the C++ front end to build qualified array types.  However,
1087    the C version of this function does not properly maintain canonical
1088    types (which are not used in C).  */
1089 tree
1090 c_build_qualified_type (tree type, int type_quals, tree /* orig_qual_type */,
1091                         size_t /* orig_qual_indirect */)
1092 {
1093   return cp_build_qualified_type (type, type_quals);
1094 }
1095
1096 \f
1097 /* Make a variant of TYPE, qualified with the TYPE_QUALS.  Handles
1098    arrays correctly.  In particular, if TYPE is an array of T's, and
1099    TYPE_QUALS is non-empty, returns an array of qualified T's.
1100
1101    FLAGS determines how to deal with ill-formed qualifications. If
1102    tf_ignore_bad_quals is set, then bad qualifications are dropped
1103    (this is permitted if TYPE was introduced via a typedef or template
1104    type parameter). If bad qualifications are dropped and tf_warning
1105    is set, then a warning is issued for non-const qualifications.  If
1106    tf_ignore_bad_quals is not set and tf_error is not set, we
1107    return error_mark_node. Otherwise, we issue an error, and ignore
1108    the qualifications.
1109
1110    Qualification of a reference type is valid when the reference came
1111    via a typedef or template type argument. [dcl.ref] No such
1112    dispensation is provided for qualifying a function type.  [dcl.fct]
1113    DR 295 queries this and the proposed resolution brings it into line
1114    with qualifying a reference.  We implement the DR.  We also behave
1115    in a similar manner for restricting non-pointer types.  */
1116
1117 tree
1118 cp_build_qualified_type_real (tree type,
1119                               int type_quals,
1120                               tsubst_flags_t complain)
1121 {
1122   tree result;
1123   int bad_quals = TYPE_UNQUALIFIED;
1124
1125   if (type == error_mark_node)
1126     return type;
1127
1128   if (type_quals == cp_type_quals (type))
1129     return type;
1130
1131   if (TREE_CODE (type) == ARRAY_TYPE)
1132     {
1133       /* In C++, the qualification really applies to the array element
1134          type.  Obtain the appropriately qualified element type.  */
1135       tree t;
1136       tree element_type
1137         = cp_build_qualified_type_real (TREE_TYPE (type),
1138                                         type_quals,
1139                                         complain);
1140
1141       if (element_type == error_mark_node)
1142         return error_mark_node;
1143
1144       /* See if we already have an identically qualified type.  Tests
1145          should be equivalent to those in check_qualified_type.  */
1146       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
1147         if (TREE_TYPE (t) == element_type
1148             && TYPE_NAME (t) == TYPE_NAME (type)
1149             && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
1150             && attribute_list_equal (TYPE_ATTRIBUTES (t),
1151                                      TYPE_ATTRIBUTES (type)))
1152           break;
1153
1154       if (!t)
1155         {
1156           t = build_cplus_array_type (element_type, TYPE_DOMAIN (type));
1157
1158           /* Keep the typedef name.  */
1159           if (TYPE_NAME (t) != TYPE_NAME (type))
1160             {
1161               t = build_variant_type_copy (t);
1162               TYPE_NAME (t) = TYPE_NAME (type);
1163               SET_TYPE_ALIGN (t, TYPE_ALIGN (type));
1164               TYPE_USER_ALIGN (t) = TYPE_USER_ALIGN (type);
1165             }
1166         }
1167
1168       /* Even if we already had this variant, we update
1169          TYPE_NEEDS_CONSTRUCTING and TYPE_HAS_NONTRIVIAL_DESTRUCTOR in case
1170          they changed since the variant was originally created.
1171
1172          This seems hokey; if there is some way to use a previous
1173          variant *without* coming through here,
1174          TYPE_NEEDS_CONSTRUCTING will never be updated.  */
1175       TYPE_NEEDS_CONSTRUCTING (t)
1176         = TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (element_type));
1177       TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
1178         = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TYPE_MAIN_VARIANT (element_type));
1179       return t;
1180     }
1181   else if (TREE_CODE (type) == TYPE_PACK_EXPANSION)
1182     {
1183       tree t = PACK_EXPANSION_PATTERN (type);
1184
1185       t = cp_build_qualified_type_real (t, type_quals, complain);
1186       return make_pack_expansion (t);
1187     }
1188
1189   /* A reference or method type shall not be cv-qualified.
1190      [dcl.ref], [dcl.fct].  This used to be an error, but as of DR 295
1191      (in CD1) we always ignore extra cv-quals on functions.  */
1192   if (type_quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE)
1193       && (TREE_CODE (type) == REFERENCE_TYPE
1194           || TREE_CODE (type) == FUNCTION_TYPE
1195           || TREE_CODE (type) == METHOD_TYPE))
1196     {
1197       if (TREE_CODE (type) == REFERENCE_TYPE)
1198         bad_quals |= type_quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE);
1199       type_quals &= ~(TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE);
1200     }
1201
1202   /* But preserve any function-cv-quals on a FUNCTION_TYPE.  */
1203   if (TREE_CODE (type) == FUNCTION_TYPE)
1204     type_quals |= type_memfn_quals (type);
1205
1206   /* A restrict-qualified type must be a pointer (or reference)
1207      to object or incomplete type. */
1208   if ((type_quals & TYPE_QUAL_RESTRICT)
1209       && TREE_CODE (type) != TEMPLATE_TYPE_PARM
1210       && TREE_CODE (type) != TYPENAME_TYPE
1211       && !POINTER_TYPE_P (type))
1212     {
1213       bad_quals |= TYPE_QUAL_RESTRICT;
1214       type_quals &= ~TYPE_QUAL_RESTRICT;
1215     }
1216
1217   if (bad_quals == TYPE_UNQUALIFIED
1218       || (complain & tf_ignore_bad_quals))
1219     /*OK*/;
1220   else if (!(complain & tf_error))
1221     return error_mark_node;
1222   else
1223     {
1224       tree bad_type = build_qualified_type (ptr_type_node, bad_quals);
1225       error ("%qV qualifiers cannot be applied to %qT",
1226              bad_type, type);
1227     }
1228
1229   /* Retrieve (or create) the appropriately qualified variant.  */
1230   result = build_qualified_type (type, type_quals);
1231
1232   /* Preserve exception specs and ref-qualifier since build_qualified_type
1233      doesn't know about them.  */
1234   if (TREE_CODE (result) == FUNCTION_TYPE
1235       || TREE_CODE (result) == METHOD_TYPE)
1236     {
1237       result = build_exception_variant (result, TYPE_RAISES_EXCEPTIONS (type));
1238       result = build_ref_qualified_type (result, type_memfn_rqual (type));
1239     }
1240
1241   return result;
1242 }
1243
1244 /* Return TYPE with const and volatile removed.  */
1245
1246 tree
1247 cv_unqualified (tree type)
1248 {
1249   int quals;
1250
1251   if (type == error_mark_node)
1252     return type;
1253
1254   quals = cp_type_quals (type);
1255   quals &= ~(TYPE_QUAL_CONST|TYPE_QUAL_VOLATILE);
1256   return cp_build_qualified_type (type, quals);
1257 }
1258
1259 /* Subroutine of strip_typedefs.  We want to apply to RESULT the attributes
1260    from ATTRIBS that affect type identity, and no others.  If any are not
1261    applied, set *remove_attributes to true.  */
1262
1263 static tree
1264 apply_identity_attributes (tree result, tree attribs, bool *remove_attributes)
1265 {
1266   tree first_ident = NULL_TREE;
1267   tree new_attribs = NULL_TREE;
1268   tree *p = &new_attribs;
1269
1270   if (OVERLOAD_TYPE_P (result))
1271     {
1272       /* On classes and enums all attributes are ingrained.  */
1273       gcc_assert (attribs == TYPE_ATTRIBUTES (result));
1274       return result;
1275     }
1276
1277   for (tree a = attribs; a; a = TREE_CHAIN (a))
1278     {
1279       const attribute_spec *as
1280         = lookup_attribute_spec (get_attribute_name (a));
1281       if (as && as->affects_type_identity)
1282         {
1283           if (!first_ident)
1284             first_ident = a;
1285           else if (first_ident == error_mark_node)
1286             {
1287               *p = tree_cons (TREE_PURPOSE (a), TREE_VALUE (a), NULL_TREE);
1288               p = &TREE_CHAIN (*p);
1289             }
1290         }
1291       else if (first_ident)
1292         {
1293           for (tree a2 = first_ident; a2; a2 = TREE_CHAIN (a2))
1294             {
1295               *p = tree_cons (TREE_PURPOSE (a2), TREE_VALUE (a2), NULL_TREE);
1296               p = &TREE_CHAIN (*p);
1297             }
1298           first_ident = error_mark_node;
1299         }
1300     }
1301   if (first_ident != error_mark_node)
1302     new_attribs = first_ident;
1303
1304   if (first_ident == attribs)
1305     /* All attributes affected type identity.  */;
1306   else
1307     *remove_attributes = true;
1308
1309   return cp_build_type_attribute_variant (result, new_attribs);
1310 }
1311
1312 /* Builds a qualified variant of T that is not a typedef variant.
1313    E.g. consider the following declarations:
1314      typedef const int ConstInt;
1315      typedef ConstInt* PtrConstInt;
1316    If T is PtrConstInt, this function returns a type representing
1317      const int*.
1318    In other words, if T is a typedef, the function returns the underlying type.
1319    The cv-qualification and attributes of the type returned match the
1320    input type.
1321    They will always be compatible types.
1322    The returned type is built so that all of its subtypes
1323    recursively have their typedefs stripped as well.
1324
1325    This is different from just returning TYPE_CANONICAL (T)
1326    Because of several reasons:
1327     * If T is a type that needs structural equality
1328       its TYPE_CANONICAL (T) will be NULL.
1329     * TYPE_CANONICAL (T) desn't carry type attributes
1330       and loses template parameter names.
1331
1332    If REMOVE_ATTRIBUTES is non-null, also strip attributes that don't
1333    affect type identity, and set the referent to true if any were
1334    stripped.  */
1335
1336 tree
1337 strip_typedefs (tree t, bool *remove_attributes)
1338 {
1339   tree result = NULL, type = NULL, t0 = NULL;
1340
1341   if (!t || t == error_mark_node)
1342     return t;
1343
1344   if (TREE_CODE (t) == TREE_LIST)
1345     {
1346       bool changed = false;
1347       vec<tree,va_gc> *vec = make_tree_vector ();
1348       tree r = t;
1349       for (; t; t = TREE_CHAIN (t))
1350         {
1351           gcc_assert (!TREE_PURPOSE (t));
1352           tree elt = strip_typedefs (TREE_VALUE (t), remove_attributes);
1353           if (elt != TREE_VALUE (t))
1354             changed = true;
1355           vec_safe_push (vec, elt);
1356         }
1357       if (changed)
1358         r = build_tree_list_vec (vec);
1359       release_tree_vector (vec);
1360       return r;
1361     }
1362
1363   gcc_assert (TYPE_P (t));
1364
1365   if (t == TYPE_CANONICAL (t))
1366     return t;
1367
1368   if (dependent_alias_template_spec_p (t))
1369     /* DR 1558: However, if the template-id is dependent, subsequent
1370        template argument substitution still applies to the template-id.  */
1371     return t;
1372
1373   switch (TREE_CODE (t))
1374     {
1375     case POINTER_TYPE:
1376       type = strip_typedefs (TREE_TYPE (t), remove_attributes);
1377       result = build_pointer_type (type);
1378       break;
1379     case REFERENCE_TYPE:
1380       type = strip_typedefs (TREE_TYPE (t), remove_attributes);
1381       result = cp_build_reference_type (type, TYPE_REF_IS_RVALUE (t));
1382       break;
1383     case OFFSET_TYPE:
1384       t0 = strip_typedefs (TYPE_OFFSET_BASETYPE (t), remove_attributes);
1385       type = strip_typedefs (TREE_TYPE (t), remove_attributes);
1386       result = build_offset_type (t0, type);
1387       break;
1388     case RECORD_TYPE:
1389       if (TYPE_PTRMEMFUNC_P (t))
1390         {
1391           t0 = strip_typedefs (TYPE_PTRMEMFUNC_FN_TYPE (t), remove_attributes);
1392           result = build_ptrmemfunc_type (t0);
1393         }
1394       break;
1395     case ARRAY_TYPE:
1396       type = strip_typedefs (TREE_TYPE (t), remove_attributes);
1397       t0  = strip_typedefs (TYPE_DOMAIN (t), remove_attributes);
1398       result = build_cplus_array_type (type, t0);
1399       break;
1400     case FUNCTION_TYPE:
1401     case METHOD_TYPE:
1402       {
1403         tree arg_types = NULL, arg_node, arg_node2, arg_type;
1404         bool changed;
1405
1406         /* Because we stomp on TREE_PURPOSE of TYPE_ARG_TYPES in many places
1407            around the compiler (e.g. cp_parser_late_parsing_default_args), we
1408            can't expect that re-hashing a function type will find a previous
1409            equivalent type, so try to reuse the input type if nothing has
1410            changed.  If the type is itself a variant, that will change.  */
1411         bool is_variant = typedef_variant_p (t);
1412         if (remove_attributes
1413             && (TYPE_ATTRIBUTES (t) || TYPE_USER_ALIGN (t)))
1414           is_variant = true;
1415
1416         type = strip_typedefs (TREE_TYPE (t), remove_attributes);
1417         changed = type != TREE_TYPE (t) || is_variant;
1418
1419         for (arg_node = TYPE_ARG_TYPES (t);
1420              arg_node;
1421              arg_node = TREE_CHAIN (arg_node))
1422           {
1423             if (arg_node == void_list_node)
1424               break;
1425             arg_type = strip_typedefs (TREE_VALUE (arg_node),
1426                                        remove_attributes);
1427             gcc_assert (arg_type);
1428             if (arg_type == TREE_VALUE (arg_node) && !changed)
1429               continue;
1430
1431             if (!changed)
1432               {
1433                 changed = true;
1434                 for (arg_node2 = TYPE_ARG_TYPES (t);
1435                      arg_node2 != arg_node;
1436                      arg_node2 = TREE_CHAIN (arg_node2))
1437                   arg_types
1438                     = tree_cons (TREE_PURPOSE (arg_node2),
1439                                  TREE_VALUE (arg_node2), arg_types);
1440               }
1441
1442             arg_types
1443               = tree_cons (TREE_PURPOSE (arg_node), arg_type, arg_types);
1444           }
1445
1446         if (!changed)
1447           return t;
1448
1449         if (arg_types)
1450           arg_types = nreverse (arg_types);
1451
1452         /* A list of parameters not ending with an ellipsis
1453            must end with void_list_node.  */
1454         if (arg_node)
1455           arg_types = chainon (arg_types, void_list_node);
1456
1457         if (TREE_CODE (t) == METHOD_TYPE)
1458           {
1459             tree class_type = TREE_TYPE (TREE_VALUE (arg_types));
1460             gcc_assert (class_type);
1461             result =
1462               build_method_type_directly (class_type, type,
1463                                           TREE_CHAIN (arg_types));
1464             result
1465               = build_ref_qualified_type (result, type_memfn_rqual (t));
1466           }
1467         else
1468           {
1469             result = build_function_type (type,
1470                                           arg_types);
1471             result = apply_memfn_quals (result,
1472                                         type_memfn_quals (t),
1473                                         type_memfn_rqual (t));
1474           }
1475
1476         if (TYPE_RAISES_EXCEPTIONS (t))
1477           result = build_exception_variant (result,
1478                                             TYPE_RAISES_EXCEPTIONS (t));
1479         if (TYPE_HAS_LATE_RETURN_TYPE (t))
1480           TYPE_HAS_LATE_RETURN_TYPE (result) = 1;
1481       }
1482       break;
1483     case TYPENAME_TYPE:
1484       {
1485         tree fullname = TYPENAME_TYPE_FULLNAME (t);
1486         if (TREE_CODE (fullname) == TEMPLATE_ID_EXPR
1487             && TREE_OPERAND (fullname, 1))
1488           {
1489             tree args = TREE_OPERAND (fullname, 1);
1490             tree new_args = copy_node (args);
1491             bool changed = false;
1492             for (int i = 0; i < TREE_VEC_LENGTH (args); ++i)
1493               {
1494                 tree arg = TREE_VEC_ELT (args, i);
1495                 tree strip_arg;
1496                 if (TYPE_P (arg))
1497                   strip_arg = strip_typedefs (arg, remove_attributes);
1498                 else
1499                   strip_arg = strip_typedefs_expr (arg, remove_attributes);
1500                 TREE_VEC_ELT (new_args, i) = strip_arg;
1501                 if (strip_arg != arg)
1502                   changed = true;
1503               }
1504             if (changed)
1505               {
1506                 NON_DEFAULT_TEMPLATE_ARGS_COUNT (new_args)
1507                   = NON_DEFAULT_TEMPLATE_ARGS_COUNT (args);
1508                 fullname
1509                   = lookup_template_function (TREE_OPERAND (fullname, 0),
1510                                               new_args);
1511               }
1512             else
1513               ggc_free (new_args);
1514           }
1515         result = make_typename_type (strip_typedefs (TYPE_CONTEXT (t),
1516                                                      remove_attributes),
1517                                      fullname, typename_type, tf_none);
1518         /* Handle 'typedef typename A::N N;'  */
1519         if (typedef_variant_p (result))
1520           result = TYPE_MAIN_VARIANT (DECL_ORIGINAL_TYPE (TYPE_NAME (result)));
1521       }
1522       break;
1523     case DECLTYPE_TYPE:
1524       result = strip_typedefs_expr (DECLTYPE_TYPE_EXPR (t),
1525                                     remove_attributes);
1526       if (result == DECLTYPE_TYPE_EXPR (t))
1527         result = NULL_TREE;
1528       else
1529         result = (finish_decltype_type
1530                   (result,
1531                    DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t),
1532                    tf_none));
1533       break;
1534     default:
1535       break;
1536     }
1537
1538   if (!result)
1539     {
1540       if (typedef_variant_p (t))
1541         {
1542           /* Explicitly get the underlying type, as TYPE_MAIN_VARIANT doesn't
1543              strip typedefs with attributes.  */
1544           result = TYPE_MAIN_VARIANT (DECL_ORIGINAL_TYPE (TYPE_NAME (t)));
1545           result = strip_typedefs (result);
1546         }
1547       else
1548         result = TYPE_MAIN_VARIANT (t);
1549     }
1550   gcc_assert (!typedef_variant_p (result));
1551
1552   if (COMPLETE_TYPE_P (result) && !COMPLETE_TYPE_P (t))
1553   /* If RESULT is complete and T isn't, it's likely the case that T
1554      is a variant of RESULT which hasn't been updated yet.  Skip the
1555      attribute handling.  */;
1556   else
1557     {
1558       if (TYPE_USER_ALIGN (t) != TYPE_USER_ALIGN (result)
1559           || TYPE_ALIGN (t) != TYPE_ALIGN (result))
1560         {
1561           gcc_assert (TYPE_USER_ALIGN (t));
1562           if (remove_attributes)
1563             *remove_attributes = true;
1564           else
1565             {
1566               if (TYPE_ALIGN (t) == TYPE_ALIGN (result))
1567                 result = build_variant_type_copy (result);
1568               else
1569                 result = build_aligned_type (result, TYPE_ALIGN (t));
1570               TYPE_USER_ALIGN (result) = true;
1571             }
1572         }
1573
1574       if (TYPE_ATTRIBUTES (t))
1575         {
1576           if (remove_attributes)
1577             result = apply_identity_attributes (result, TYPE_ATTRIBUTES (t),
1578                                                 remove_attributes);
1579           else
1580             result = cp_build_type_attribute_variant (result,
1581                                                       TYPE_ATTRIBUTES (t));
1582         }
1583     }
1584
1585   return cp_build_qualified_type (result, cp_type_quals (t));
1586 }
1587
1588 /* Like strip_typedefs above, but works on expressions, so that in
1589
1590    template<class T> struct A
1591    {
1592      typedef T TT;
1593      B<sizeof(TT)> b;
1594    };
1595
1596    sizeof(TT) is replaced by sizeof(T).  */
1597
1598 tree
1599 strip_typedefs_expr (tree t, bool *remove_attributes)
1600 {
1601   unsigned i,n;
1602   tree r, type, *ops;
1603   enum tree_code code;
1604
1605   if (t == NULL_TREE || t == error_mark_node)
1606     return t;
1607
1608   if (DECL_P (t) || CONSTANT_CLASS_P (t))
1609     return t;
1610
1611   /* Some expressions have type operands, so let's handle types here rather
1612      than check TYPE_P in multiple places below.  */
1613   if (TYPE_P (t))
1614     return strip_typedefs (t, remove_attributes);
1615
1616   code = TREE_CODE (t);
1617   switch (code)
1618     {
1619     case IDENTIFIER_NODE:
1620     case TEMPLATE_PARM_INDEX:
1621     case OVERLOAD:
1622     case BASELINK:
1623     case ARGUMENT_PACK_SELECT:
1624       return t;
1625
1626     case TRAIT_EXPR:
1627       {
1628         tree type1 = strip_typedefs (TRAIT_EXPR_TYPE1 (t), remove_attributes);
1629         tree type2 = strip_typedefs (TRAIT_EXPR_TYPE2 (t), remove_attributes);
1630         if (type1 == TRAIT_EXPR_TYPE1 (t)
1631             && type2 == TRAIT_EXPR_TYPE2 (t))
1632           return t;
1633         r = copy_node (t);
1634         TRAIT_EXPR_TYPE1 (r) = type1;
1635         TRAIT_EXPR_TYPE2 (r) = type2;
1636         return r;
1637       }
1638
1639     case TREE_LIST:
1640       {
1641         vec<tree, va_gc> *vec = make_tree_vector ();
1642         bool changed = false;
1643         tree it;
1644         for (it = t; it; it = TREE_CHAIN (it))
1645           {
1646             tree val = strip_typedefs_expr (TREE_VALUE (t), remove_attributes);
1647             vec_safe_push (vec, val);
1648             if (val != TREE_VALUE (t))
1649               changed = true;
1650             gcc_assert (TREE_PURPOSE (it) == NULL_TREE);
1651           }
1652         if (changed)
1653           {
1654             r = NULL_TREE;
1655             FOR_EACH_VEC_ELT_REVERSE (*vec, i, it)
1656               r = tree_cons (NULL_TREE, it, r);
1657           }
1658         else
1659           r = t;
1660         release_tree_vector (vec);
1661         return r;
1662       }
1663
1664     case TREE_VEC:
1665       {
1666         bool changed = false;
1667         vec<tree, va_gc> *vec = make_tree_vector ();
1668         n = TREE_VEC_LENGTH (t);
1669         vec_safe_reserve (vec, n);
1670         for (i = 0; i < n; ++i)
1671           {
1672             tree op = strip_typedefs_expr (TREE_VEC_ELT (t, i),
1673                                            remove_attributes);
1674             vec->quick_push (op);
1675             if (op != TREE_VEC_ELT (t, i))
1676               changed = true;
1677           }
1678         if (changed)
1679           {
1680             r = copy_node (t);
1681             for (i = 0; i < n; ++i)
1682               TREE_VEC_ELT (r, i) = (*vec)[i];
1683             NON_DEFAULT_TEMPLATE_ARGS_COUNT (r)
1684               = NON_DEFAULT_TEMPLATE_ARGS_COUNT (t);
1685           }
1686         else
1687           r = t;
1688         release_tree_vector (vec);
1689         return r;
1690       }
1691
1692     case CONSTRUCTOR:
1693       {
1694         bool changed = false;
1695         vec<constructor_elt, va_gc> *vec
1696           = vec_safe_copy (CONSTRUCTOR_ELTS (t));
1697         n = CONSTRUCTOR_NELTS (t);
1698         type = strip_typedefs (TREE_TYPE (t), remove_attributes);
1699         for (i = 0; i < n; ++i)
1700           {
1701             constructor_elt *e = &(*vec)[i];
1702             tree op = strip_typedefs_expr (e->value, remove_attributes);
1703             if (op != e->value)
1704               {
1705                 changed = true;
1706                 e->value = op;
1707               }
1708             gcc_checking_assert
1709               (e->index == strip_typedefs_expr (e->index, remove_attributes));
1710           }
1711
1712         if (!changed && type == TREE_TYPE (t))
1713           {
1714             vec_free (vec);
1715             return t;
1716           }
1717         else
1718           {
1719             r = copy_node (t);
1720             TREE_TYPE (r) = type;
1721             CONSTRUCTOR_ELTS (r) = vec;
1722             return r;
1723           }
1724       }
1725
1726     case LAMBDA_EXPR:
1727       error ("lambda-expression in a constant expression");
1728       return error_mark_node;
1729
1730     default:
1731       break;
1732     }
1733
1734   gcc_assert (EXPR_P (t));
1735
1736   n = TREE_OPERAND_LENGTH (t);
1737   ops = XALLOCAVEC (tree, n);
1738   type = TREE_TYPE (t);
1739
1740   switch (code)
1741     {
1742     CASE_CONVERT:
1743     case IMPLICIT_CONV_EXPR:
1744     case DYNAMIC_CAST_EXPR:
1745     case STATIC_CAST_EXPR:
1746     case CONST_CAST_EXPR:
1747     case REINTERPRET_CAST_EXPR:
1748     case CAST_EXPR:
1749     case NEW_EXPR:
1750       type = strip_typedefs (type, remove_attributes);
1751       /* fallthrough */
1752
1753     default:
1754       for (i = 0; i < n; ++i)
1755         ops[i] = strip_typedefs_expr (TREE_OPERAND (t, i), remove_attributes);
1756       break;
1757     }
1758
1759   /* If nothing changed, return t.  */
1760   for (i = 0; i < n; ++i)
1761     if (ops[i] != TREE_OPERAND (t, i))
1762       break;
1763   if (i == n && type == TREE_TYPE (t))
1764     return t;
1765
1766   r = copy_node (t);
1767   TREE_TYPE (r) = type;
1768   for (i = 0; i < n; ++i)
1769     TREE_OPERAND (r, i) = ops[i];
1770   return r;
1771 }
1772
1773 /* Makes a copy of BINFO and TYPE, which is to be inherited into a
1774    graph dominated by T.  If BINFO is NULL, TYPE is a dependent base,
1775    and we do a shallow copy.  If BINFO is non-NULL, we do a deep copy.
1776    VIRT indicates whether TYPE is inherited virtually or not.
1777    IGO_PREV points at the previous binfo of the inheritance graph
1778    order chain.  The newly copied binfo's TREE_CHAIN forms this
1779    ordering.
1780
1781    The CLASSTYPE_VBASECLASSES vector of T is constructed in the
1782    correct order. That is in the order the bases themselves should be
1783    constructed in.
1784
1785    The BINFO_INHERITANCE of a virtual base class points to the binfo
1786    of the most derived type. ??? We could probably change this so that
1787    BINFO_INHERITANCE becomes synonymous with BINFO_PRIMARY, and hence
1788    remove a field.  They currently can only differ for primary virtual
1789    virtual bases.  */
1790
1791 tree
1792 copy_binfo (tree binfo, tree type, tree t, tree *igo_prev, int virt)
1793 {
1794   tree new_binfo;
1795
1796   if (virt)
1797     {
1798       /* See if we've already made this virtual base.  */
1799       new_binfo = binfo_for_vbase (type, t);
1800       if (new_binfo)
1801         return new_binfo;
1802     }
1803
1804   new_binfo = make_tree_binfo (binfo ? BINFO_N_BASE_BINFOS (binfo) : 0);
1805   BINFO_TYPE (new_binfo) = type;
1806
1807   /* Chain it into the inheritance graph.  */
1808   TREE_CHAIN (*igo_prev) = new_binfo;
1809   *igo_prev = new_binfo;
1810
1811   if (binfo && !BINFO_DEPENDENT_BASE_P (binfo))
1812     {
1813       int ix;
1814       tree base_binfo;
1815
1816       gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), type));
1817
1818       BINFO_OFFSET (new_binfo) = BINFO_OFFSET (binfo);
1819       BINFO_VIRTUALS (new_binfo) = BINFO_VIRTUALS (binfo);
1820
1821       /* We do not need to copy the accesses, as they are read only.  */
1822       BINFO_BASE_ACCESSES (new_binfo) = BINFO_BASE_ACCESSES (binfo);
1823
1824       /* Recursively copy base binfos of BINFO.  */
1825       for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++)
1826         {
1827           tree new_base_binfo;
1828           new_base_binfo = copy_binfo (base_binfo, BINFO_TYPE (base_binfo),
1829                                        t, igo_prev,
1830                                        BINFO_VIRTUAL_P (base_binfo));
1831
1832           if (!BINFO_INHERITANCE_CHAIN (new_base_binfo))
1833             BINFO_INHERITANCE_CHAIN (new_base_binfo) = new_binfo;
1834           BINFO_BASE_APPEND (new_binfo, new_base_binfo);
1835         }
1836     }
1837   else
1838     BINFO_DEPENDENT_BASE_P (new_binfo) = 1;
1839
1840   if (virt)
1841     {
1842       /* Push it onto the list after any virtual bases it contains
1843          will have been pushed.  */
1844       CLASSTYPE_VBASECLASSES (t)->quick_push (new_binfo);
1845       BINFO_VIRTUAL_P (new_binfo) = 1;
1846       BINFO_INHERITANCE_CHAIN (new_binfo) = TYPE_BINFO (t);
1847     }
1848
1849   return new_binfo;
1850 }
1851 \f
1852 /* Hashing of lists so that we don't make duplicates.
1853    The entry point is `list_hash_canon'.  */
1854
1855 struct list_proxy
1856 {
1857   tree purpose;
1858   tree value;
1859   tree chain;
1860 };
1861
1862 struct list_hasher : ggc_ptr_hash<tree_node>
1863 {
1864   typedef list_proxy *compare_type;
1865
1866   static hashval_t hash (tree);
1867   static bool equal (tree, list_proxy *);
1868 };
1869
1870 /* Now here is the hash table.  When recording a list, it is added
1871    to the slot whose index is the hash code mod the table size.
1872    Note that the hash table is used for several kinds of lists.
1873    While all these live in the same table, they are completely independent,
1874    and the hash code is computed differently for each of these.  */
1875
1876 static GTY (()) hash_table<list_hasher> *list_hash_table;
1877
1878 /* Compare ENTRY (an entry in the hash table) with DATA (a list_proxy
1879    for a node we are thinking about adding).  */
1880
1881 bool
1882 list_hasher::equal (tree t, list_proxy *proxy)
1883 {
1884   return (TREE_VALUE (t) == proxy->value
1885           && TREE_PURPOSE (t) == proxy->purpose
1886           && TREE_CHAIN (t) == proxy->chain);
1887 }
1888
1889 /* Compute a hash code for a list (chain of TREE_LIST nodes
1890    with goodies in the TREE_PURPOSE, TREE_VALUE, and bits of the
1891    TREE_COMMON slots), by adding the hash codes of the individual entries.  */
1892
1893 static hashval_t
1894 list_hash_pieces (tree purpose, tree value, tree chain)
1895 {
1896   hashval_t hashcode = 0;
1897
1898   if (chain)
1899     hashcode += TREE_HASH (chain);
1900
1901   if (value)
1902     hashcode += TREE_HASH (value);
1903   else
1904     hashcode += 1007;
1905   if (purpose)
1906     hashcode += TREE_HASH (purpose);
1907   else
1908     hashcode += 1009;
1909   return hashcode;
1910 }
1911
1912 /* Hash an already existing TREE_LIST.  */
1913
1914 hashval_t
1915 list_hasher::hash (tree t)
1916 {
1917   return list_hash_pieces (TREE_PURPOSE (t),
1918                            TREE_VALUE (t),
1919                            TREE_CHAIN (t));
1920 }
1921
1922 /* Given list components PURPOSE, VALUE, AND CHAIN, return the canonical
1923    object for an identical list if one already exists.  Otherwise, build a
1924    new one, and record it as the canonical object.  */
1925
1926 tree
1927 hash_tree_cons (tree purpose, tree value, tree chain)
1928 {
1929   int hashcode = 0;
1930   tree *slot;
1931   struct list_proxy proxy;
1932
1933   /* Hash the list node.  */
1934   hashcode = list_hash_pieces (purpose, value, chain);
1935   /* Create a proxy for the TREE_LIST we would like to create.  We
1936      don't actually create it so as to avoid creating garbage.  */
1937   proxy.purpose = purpose;
1938   proxy.value = value;
1939   proxy.chain = chain;
1940   /* See if it is already in the table.  */
1941   slot = list_hash_table->find_slot_with_hash (&proxy, hashcode, INSERT);
1942   /* If not, create a new node.  */
1943   if (!*slot)
1944     *slot = tree_cons (purpose, value, chain);
1945   return (tree) *slot;
1946 }
1947
1948 /* Constructor for hashed lists.  */
1949
1950 tree
1951 hash_tree_chain (tree value, tree chain)
1952 {
1953   return hash_tree_cons (NULL_TREE, value, chain);
1954 }
1955 \f
1956 void
1957 debug_binfo (tree elem)
1958 {
1959   HOST_WIDE_INT n;
1960   tree virtuals;
1961
1962   fprintf (stderr, "type \"%s\", offset = " HOST_WIDE_INT_PRINT_DEC
1963            "\nvtable type:\n",
1964            TYPE_NAME_STRING (BINFO_TYPE (elem)),
1965            TREE_INT_CST_LOW (BINFO_OFFSET (elem)));
1966   debug_tree (BINFO_TYPE (elem));
1967   if (BINFO_VTABLE (elem))
1968     fprintf (stderr, "vtable decl \"%s\"\n",
1969              IDENTIFIER_POINTER (DECL_NAME (get_vtbl_decl_for_binfo (elem))));
1970   else
1971     fprintf (stderr, "no vtable decl yet\n");
1972   fprintf (stderr, "virtuals:\n");
1973   virtuals = BINFO_VIRTUALS (elem);
1974   n = 0;
1975
1976   while (virtuals)
1977     {
1978       tree fndecl = TREE_VALUE (virtuals);
1979       fprintf (stderr, "%s [%ld =? %ld]\n",
1980                IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (fndecl)),
1981                (long) n, (long) TREE_INT_CST_LOW (DECL_VINDEX (fndecl)));
1982       ++n;
1983       virtuals = TREE_CHAIN (virtuals);
1984     }
1985 }
1986
1987 /* Build a representation for the qualified name SCOPE::NAME.  TYPE is
1988    the type of the result expression, if known, or NULL_TREE if the
1989    resulting expression is type-dependent.  If TEMPLATE_P is true,
1990    NAME is known to be a template because the user explicitly used the
1991    "template" keyword after the "::".
1992
1993    All SCOPE_REFs should be built by use of this function.  */
1994
1995 tree
1996 build_qualified_name (tree type, tree scope, tree name, bool template_p)
1997 {
1998   tree t;
1999   if (type == error_mark_node
2000       || scope == error_mark_node
2001       || name == error_mark_node)
2002     return error_mark_node;
2003   t = build2 (SCOPE_REF, type, scope, name);
2004   QUALIFIED_NAME_IS_TEMPLATE (t) = template_p;
2005   PTRMEM_OK_P (t) = true;
2006   if (type)
2007     t = convert_from_reference (t);
2008   return t;
2009 }
2010
2011 /* Like check_qualified_type, but also check ref-qualifier and exception
2012    specification.  */
2013
2014 static bool
2015 cp_check_qualified_type (const_tree cand, const_tree base, int type_quals,
2016                          cp_ref_qualifier rqual, tree raises)
2017 {
2018   return (TYPE_QUALS (cand) == type_quals
2019           && check_base_type (cand, base)
2020           && comp_except_specs (raises, TYPE_RAISES_EXCEPTIONS (cand),
2021                                 ce_exact)
2022           && type_memfn_rqual (cand) == rqual);
2023 }
2024
2025 /* Build the FUNCTION_TYPE or METHOD_TYPE with the ref-qualifier RQUAL.  */
2026
2027 tree
2028 build_ref_qualified_type (tree type, cp_ref_qualifier rqual)
2029 {
2030   tree t;
2031
2032   if (rqual == type_memfn_rqual (type))
2033     return type;
2034
2035   int type_quals = TYPE_QUALS (type);
2036   tree raises = TYPE_RAISES_EXCEPTIONS (type);
2037   for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
2038     if (cp_check_qualified_type (t, type, type_quals, rqual, raises))
2039       return t;
2040
2041   t = build_variant_type_copy (type);
2042   switch (rqual)
2043     {
2044     case REF_QUAL_RVALUE:
2045       FUNCTION_RVALUE_QUALIFIED (t) = 1;
2046       FUNCTION_REF_QUALIFIED (t) = 1;
2047       break;
2048     case REF_QUAL_LVALUE:
2049       FUNCTION_RVALUE_QUALIFIED (t) = 0;
2050       FUNCTION_REF_QUALIFIED (t) = 1;
2051       break;
2052     default:
2053       FUNCTION_REF_QUALIFIED (t) = 0;
2054       break;
2055     }
2056
2057   if (TYPE_STRUCTURAL_EQUALITY_P (type))
2058     /* Propagate structural equality. */
2059     SET_TYPE_STRUCTURAL_EQUALITY (t);
2060   else if (TYPE_CANONICAL (type) != type)
2061     /* Build the underlying canonical type, since it is different
2062        from TYPE. */
2063     TYPE_CANONICAL (t) = build_ref_qualified_type (TYPE_CANONICAL (type),
2064                                                    rqual);
2065   else
2066     /* T is its own canonical type. */
2067     TYPE_CANONICAL (t) = t;
2068
2069   return t;
2070 }
2071
2072 /* Returns nonzero if X is an expression for a (possibly overloaded)
2073    function.  If "f" is a function or function template, "f", "c->f",
2074    "c.f", "C::f", and "f<int>" will all be considered possibly
2075    overloaded functions.  Returns 2 if the function is actually
2076    overloaded, i.e., if it is impossible to know the type of the
2077    function without performing overload resolution.  */
2078
2079 int
2080 is_overloaded_fn (tree x)
2081 {
2082   /* A baselink is also considered an overloaded function.  */
2083   if (TREE_CODE (x) == OFFSET_REF
2084       || TREE_CODE (x) == COMPONENT_REF)
2085     x = TREE_OPERAND (x, 1);
2086   if (BASELINK_P (x))
2087     x = BASELINK_FUNCTIONS (x);
2088   if (TREE_CODE (x) == TEMPLATE_ID_EXPR)
2089     x = TREE_OPERAND (x, 0);
2090   if (DECL_FUNCTION_TEMPLATE_P (OVL_CURRENT (x))
2091       || (TREE_CODE (x) == OVERLOAD && OVL_CHAIN (x)))
2092     return 2;
2093   return  (TREE_CODE (x) == FUNCTION_DECL
2094            || TREE_CODE (x) == OVERLOAD);
2095 }
2096
2097 /* X is the CALL_EXPR_FN of a CALL_EXPR.  If X represents a dependent name
2098    (14.6.2), return the IDENTIFIER_NODE for that name.  Otherwise, return
2099    NULL_TREE.  */
2100
2101 tree
2102 dependent_name (tree x)
2103 {
2104   if (identifier_p (x))
2105     return x;
2106   if (TREE_CODE (x) != COMPONENT_REF
2107       && TREE_CODE (x) != OFFSET_REF
2108       && TREE_CODE (x) != BASELINK
2109       && is_overloaded_fn (x))
2110     return DECL_NAME (get_first_fn (x));
2111   return NULL_TREE;
2112 }
2113
2114 /* Returns true iff X is an expression for an overloaded function
2115    whose type cannot be known without performing overload
2116    resolution.  */
2117
2118 bool
2119 really_overloaded_fn (tree x)
2120 {
2121   return is_overloaded_fn (x) == 2;
2122 }
2123
2124 tree
2125 get_fns (tree from)
2126 {
2127   gcc_assert (is_overloaded_fn (from));
2128   /* A baselink is also considered an overloaded function.  */
2129   if (TREE_CODE (from) == OFFSET_REF
2130       || TREE_CODE (from) == COMPONENT_REF)
2131     from = TREE_OPERAND (from, 1);
2132   if (BASELINK_P (from))
2133     from = BASELINK_FUNCTIONS (from);
2134   if (TREE_CODE (from) == TEMPLATE_ID_EXPR)
2135     from = TREE_OPERAND (from, 0);
2136   return from;
2137 }
2138
2139 tree
2140 get_first_fn (tree from)
2141 {
2142   return OVL_CURRENT (get_fns (from));
2143 }
2144
2145 /* Return a new OVL node, concatenating it with the old one.  */
2146
2147 tree
2148 ovl_cons (tree decl, tree chain)
2149 {
2150   tree result = make_node (OVERLOAD);
2151   TREE_TYPE (result) = unknown_type_node;
2152   OVL_FUNCTION (result) = decl;
2153   TREE_CHAIN (result) = chain;
2154
2155   return result;
2156 }
2157
2158 /* Build a new overloaded function. If this is the first one,
2159    just return it; otherwise, ovl_cons the _DECLs */
2160
2161 tree
2162 build_overload (tree decl, tree chain)
2163 {
2164   if (! chain && TREE_CODE (decl) != TEMPLATE_DECL)
2165     return decl;
2166   return ovl_cons (decl, chain);
2167 }
2168
2169 /* Return the scope where the overloaded functions OVL were found.  */
2170
2171 tree
2172 ovl_scope (tree ovl)
2173 {
2174   if (TREE_CODE (ovl) == OFFSET_REF
2175       || TREE_CODE (ovl) == COMPONENT_REF)
2176     ovl = TREE_OPERAND (ovl, 1);
2177   if (TREE_CODE (ovl) == BASELINK)
2178     return BINFO_TYPE (BASELINK_BINFO (ovl));
2179   if (TREE_CODE (ovl) == TEMPLATE_ID_EXPR)
2180     ovl = TREE_OPERAND (ovl, 0);
2181   /* Skip using-declarations.  */
2182   while (TREE_CODE (ovl) == OVERLOAD && OVL_USED (ovl) && OVL_CHAIN (ovl))
2183     ovl = OVL_CHAIN (ovl);
2184   return CP_DECL_CONTEXT (OVL_CURRENT (ovl));
2185 }
2186 \f
2187 #define PRINT_RING_SIZE 4
2188
2189 static const char *
2190 cxx_printable_name_internal (tree decl, int v, bool translate)
2191 {
2192   static unsigned int uid_ring[PRINT_RING_SIZE];
2193   static char *print_ring[PRINT_RING_SIZE];
2194   static bool trans_ring[PRINT_RING_SIZE];
2195   static int ring_counter;
2196   int i;
2197
2198   /* Only cache functions.  */
2199   if (v < 2
2200       || TREE_CODE (decl) != FUNCTION_DECL
2201       || DECL_LANG_SPECIFIC (decl) == 0)
2202     return lang_decl_name (decl, v, translate);
2203
2204   /* See if this print name is lying around.  */
2205   for (i = 0; i < PRINT_RING_SIZE; i++)
2206     if (uid_ring[i] == DECL_UID (decl) && translate == trans_ring[i])
2207       /* yes, so return it.  */
2208       return print_ring[i];
2209
2210   if (++ring_counter == PRINT_RING_SIZE)
2211     ring_counter = 0;
2212
2213   if (current_function_decl != NULL_TREE)
2214     {
2215       /* There may be both translated and untranslated versions of the
2216          name cached.  */
2217       for (i = 0; i < 2; i++)
2218         {
2219           if (uid_ring[ring_counter] == DECL_UID (current_function_decl))
2220             ring_counter += 1;
2221           if (ring_counter == PRINT_RING_SIZE)
2222             ring_counter = 0;
2223         }
2224       gcc_assert (uid_ring[ring_counter] != DECL_UID (current_function_decl));
2225     }
2226
2227   free (print_ring[ring_counter]);
2228
2229   print_ring[ring_counter] = xstrdup (lang_decl_name (decl, v, translate));
2230   uid_ring[ring_counter] = DECL_UID (decl);
2231   trans_ring[ring_counter] = translate;
2232   return print_ring[ring_counter];
2233 }
2234
2235 const char *
2236 cxx_printable_name (tree decl, int v)
2237 {
2238   return cxx_printable_name_internal (decl, v, false);
2239 }
2240
2241 const char *
2242 cxx_printable_name_translate (tree decl, int v)
2243 {
2244   return cxx_printable_name_internal (decl, v, true);
2245 }
2246 \f
2247 /* Return the canonical version of exception-specification RAISES for a C++17
2248    function type, for use in type comparison and building TYPE_CANONICAL.  */
2249
2250 tree
2251 canonical_eh_spec (tree raises)
2252 {
2253   if (raises == NULL_TREE)
2254     return raises;
2255   else if (DEFERRED_NOEXCEPT_SPEC_P (raises)
2256            || uses_template_parms (raises)
2257            || uses_template_parms (TREE_PURPOSE (raises)))
2258     /* Keep a dependent or deferred exception specification.  */
2259     return raises;
2260   else if (nothrow_spec_p (raises))
2261     /* throw() -> noexcept.  */
2262     return noexcept_true_spec;
2263   else
2264     /* For C++17 type matching, anything else -> nothing.  */
2265     return NULL_TREE;
2266 }
2267
2268 /* Build the FUNCTION_TYPE or METHOD_TYPE which may throw exceptions
2269    listed in RAISES.  */
2270
2271 tree
2272 build_exception_variant (tree type, tree raises)
2273 {
2274   tree v;
2275   int type_quals;
2276
2277   if (comp_except_specs (raises, TYPE_RAISES_EXCEPTIONS (type), ce_exact))
2278     return type;
2279
2280   type_quals = TYPE_QUALS (type);
2281   cp_ref_qualifier rqual = type_memfn_rqual (type);
2282   for (v = TYPE_MAIN_VARIANT (type); v; v = TYPE_NEXT_VARIANT (v))
2283     if (cp_check_qualified_type (v, type, type_quals, rqual, raises))
2284       return v;
2285
2286   /* Need to build a new variant.  */
2287   v = build_variant_type_copy (type);
2288   TYPE_RAISES_EXCEPTIONS (v) = raises;
2289
2290   if (!flag_noexcept_type)
2291     /* The exception-specification is not part of the canonical type.  */
2292     return v;
2293
2294   /* Canonicalize the exception specification.  */
2295   tree cr = canonical_eh_spec (raises);
2296
2297   if (TYPE_STRUCTURAL_EQUALITY_P (type))
2298     /* Propagate structural equality. */
2299     SET_TYPE_STRUCTURAL_EQUALITY (v);
2300   else if (TYPE_CANONICAL (type) != type || cr != raises)
2301     /* Build the underlying canonical type, since it is different
2302        from TYPE. */
2303     TYPE_CANONICAL (v) = build_exception_variant (TYPE_CANONICAL (type), cr);
2304   else
2305     /* T is its own canonical type. */
2306     TYPE_CANONICAL (v) = v;
2307
2308   return v;
2309 }
2310
2311 /* Given a TEMPLATE_TEMPLATE_PARM node T, create a new
2312    BOUND_TEMPLATE_TEMPLATE_PARM bound with NEWARGS as its template
2313    arguments.  */
2314
2315 tree
2316 bind_template_template_parm (tree t, tree newargs)
2317 {
2318   tree decl = TYPE_NAME (t);
2319   tree t2;
2320
2321   t2 = cxx_make_type (BOUND_TEMPLATE_TEMPLATE_PARM);
2322   decl = build_decl (input_location,
2323                      TYPE_DECL, DECL_NAME (decl), NULL_TREE);
2324
2325   /* These nodes have to be created to reflect new TYPE_DECL and template
2326      arguments.  */
2327   TEMPLATE_TYPE_PARM_INDEX (t2) = copy_node (TEMPLATE_TYPE_PARM_INDEX (t));
2328   TEMPLATE_PARM_DECL (TEMPLATE_TYPE_PARM_INDEX (t2)) = decl;
2329   TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (t2)
2330     = build_template_info (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t), newargs);
2331
2332   TREE_TYPE (decl) = t2;
2333   TYPE_NAME (t2) = decl;
2334   TYPE_STUB_DECL (t2) = decl;
2335   TYPE_SIZE (t2) = 0;
2336   SET_TYPE_STRUCTURAL_EQUALITY (t2);
2337
2338   return t2;
2339 }
2340
2341 /* Called from count_trees via walk_tree.  */
2342
2343 static tree
2344 count_trees_r (tree *tp, int *walk_subtrees, void *data)
2345 {
2346   ++*((int *) data);
2347
2348   if (TYPE_P (*tp))
2349     *walk_subtrees = 0;
2350
2351   return NULL_TREE;
2352 }
2353
2354 /* Debugging function for measuring the rough complexity of a tree
2355    representation.  */
2356
2357 int
2358 count_trees (tree t)
2359 {
2360   int n_trees = 0;
2361   cp_walk_tree_without_duplicates (&t, count_trees_r, &n_trees);
2362   return n_trees;
2363 }
2364
2365 /* Called from verify_stmt_tree via walk_tree.  */
2366
2367 static tree
2368 verify_stmt_tree_r (tree* tp, int * /*walk_subtrees*/, void* data)
2369 {
2370   tree t = *tp;
2371   hash_table<nofree_ptr_hash <tree_node> > *statements
2372       = static_cast <hash_table<nofree_ptr_hash <tree_node> > *> (data);
2373   tree_node **slot;
2374
2375   if (!STATEMENT_CODE_P (TREE_CODE (t)))
2376     return NULL_TREE;
2377
2378   /* If this statement is already present in the hash table, then
2379      there is a circularity in the statement tree.  */
2380   gcc_assert (!statements->find (t));
2381
2382   slot = statements->find_slot (t, INSERT);
2383   *slot = t;
2384
2385   return NULL_TREE;
2386 }
2387
2388 /* Debugging function to check that the statement T has not been
2389    corrupted.  For now, this function simply checks that T contains no
2390    circularities.  */
2391
2392 void
2393 verify_stmt_tree (tree t)
2394 {
2395   hash_table<nofree_ptr_hash <tree_node> > statements (37);
2396   cp_walk_tree (&t, verify_stmt_tree_r, &statements, NULL);
2397 }
2398
2399 /* Check if the type T depends on a type with no linkage and if so, return
2400    it.  If RELAXED_P then do not consider a class type declared within
2401    a vague-linkage function to have no linkage.  */
2402
2403 tree
2404 no_linkage_check (tree t, bool relaxed_p)
2405 {
2406   tree r;
2407
2408   /* There's no point in checking linkage on template functions; we
2409      can't know their complete types.  */
2410   if (processing_template_decl)
2411     return NULL_TREE;
2412
2413   switch (TREE_CODE (t))
2414     {
2415     case RECORD_TYPE:
2416       if (TYPE_PTRMEMFUNC_P (t))
2417         goto ptrmem;
2418       /* Lambda types that don't have mangling scope have no linkage.  We
2419          check CLASSTYPE_LAMBDA_EXPR for error_mark_node because
2420          when we get here from pushtag none of the lambda information is
2421          set up yet, so we want to assume that the lambda has linkage and
2422          fix it up later if not.  */
2423       if (CLASSTYPE_LAMBDA_EXPR (t)
2424           && CLASSTYPE_LAMBDA_EXPR (t) != error_mark_node
2425           && LAMBDA_TYPE_EXTRA_SCOPE (t) == NULL_TREE)
2426         return t;
2427       /* Fall through.  */
2428     case UNION_TYPE:
2429       if (!CLASS_TYPE_P (t))
2430         return NULL_TREE;
2431       /* Fall through.  */
2432     case ENUMERAL_TYPE:
2433       /* Only treat unnamed types as having no linkage if they're at
2434          namespace scope.  This is core issue 966.  */
2435       if (TYPE_UNNAMED_P (t) && TYPE_NAMESPACE_SCOPE_P (t))
2436         return t;
2437
2438       for (r = CP_TYPE_CONTEXT (t); ; )
2439         {
2440           /* If we're a nested type of a !TREE_PUBLIC class, we might not
2441              have linkage, or we might just be in an anonymous namespace.
2442              If we're in a TREE_PUBLIC class, we have linkage.  */
2443           if (TYPE_P (r) && !TREE_PUBLIC (TYPE_NAME (r)))
2444             return no_linkage_check (TYPE_CONTEXT (t), relaxed_p);
2445           else if (TREE_CODE (r) == FUNCTION_DECL)
2446             {
2447               if (!relaxed_p || !vague_linkage_p (r))
2448                 return t;
2449               else
2450                 r = CP_DECL_CONTEXT (r);
2451             }
2452           else
2453             break;
2454         }
2455
2456       return NULL_TREE;
2457
2458     case ARRAY_TYPE:
2459     case POINTER_TYPE:
2460     case REFERENCE_TYPE:
2461     case VECTOR_TYPE:
2462       return no_linkage_check (TREE_TYPE (t), relaxed_p);
2463
2464     case OFFSET_TYPE:
2465     ptrmem:
2466       r = no_linkage_check (TYPE_PTRMEM_POINTED_TO_TYPE (t),
2467                             relaxed_p);
2468       if (r)
2469         return r;
2470       return no_linkage_check (TYPE_PTRMEM_CLASS_TYPE (t), relaxed_p);
2471
2472     case METHOD_TYPE:
2473     case FUNCTION_TYPE:
2474       {
2475         tree parm = TYPE_ARG_TYPES (t);
2476         if (TREE_CODE (t) == METHOD_TYPE)
2477           /* The 'this' pointer isn't interesting; a method has the same
2478              linkage (or lack thereof) as its enclosing class.  */
2479           parm = TREE_CHAIN (parm);
2480         for (;
2481              parm && parm != void_list_node;
2482              parm = TREE_CHAIN (parm))
2483           {
2484             r = no_linkage_check (TREE_VALUE (parm), relaxed_p);
2485             if (r)
2486               return r;
2487           }
2488         return no_linkage_check (TREE_TYPE (t), relaxed_p);
2489       }
2490
2491     default:
2492       return NULL_TREE;
2493     }
2494 }
2495
2496 extern int depth_reached;
2497
2498 void
2499 cxx_print_statistics (void)
2500 {
2501   print_search_statistics ();
2502   print_class_statistics ();
2503   print_template_statistics ();
2504   if (GATHER_STATISTICS)
2505     fprintf (stderr, "maximum template instantiation depth reached: %d\n",
2506              depth_reached);
2507 }
2508
2509 /* Return, as an INTEGER_CST node, the number of elements for TYPE
2510    (which is an ARRAY_TYPE).  This counts only elements of the top
2511    array.  */
2512
2513 tree
2514 array_type_nelts_top (tree type)
2515 {
2516   return fold_build2_loc (input_location,
2517                       PLUS_EXPR, sizetype,
2518                       array_type_nelts (type),
2519                       size_one_node);
2520 }
2521
2522 /* Return, as an INTEGER_CST node, the number of elements for TYPE
2523    (which is an ARRAY_TYPE).  This one is a recursive count of all
2524    ARRAY_TYPEs that are clumped together.  */
2525
2526 tree
2527 array_type_nelts_total (tree type)
2528 {
2529   tree sz = array_type_nelts_top (type);
2530   type = TREE_TYPE (type);
2531   while (TREE_CODE (type) == ARRAY_TYPE)
2532     {
2533       tree n = array_type_nelts_top (type);
2534       sz = fold_build2_loc (input_location,
2535                         MULT_EXPR, sizetype, sz, n);
2536       type = TREE_TYPE (type);
2537     }
2538   return sz;
2539 }
2540
2541 /* Called from break_out_target_exprs via mapcar.  */
2542
2543 static tree
2544 bot_manip (tree* tp, int* walk_subtrees, void* data)
2545 {
2546   splay_tree target_remap = ((splay_tree) data);
2547   tree t = *tp;
2548
2549   if (!TYPE_P (t) && TREE_CONSTANT (t) && !TREE_SIDE_EFFECTS (t))
2550     {
2551       /* There can't be any TARGET_EXPRs or their slot variables below this
2552          point.  But we must make a copy, in case subsequent processing
2553          alters any part of it.  For example, during gimplification a cast
2554          of the form (T) &X::f (where "f" is a member function) will lead
2555          to replacing the PTRMEM_CST for &X::f with a VAR_DECL.  */
2556       *walk_subtrees = 0;
2557       *tp = unshare_expr (t);
2558       return NULL_TREE;
2559     }
2560   if (TREE_CODE (t) == TARGET_EXPR)
2561     {
2562       tree u;
2563
2564       if (TREE_CODE (TREE_OPERAND (t, 1)) == AGGR_INIT_EXPR)
2565         {
2566           u = build_cplus_new (TREE_TYPE (t), TREE_OPERAND (t, 1),
2567                                tf_warning_or_error);
2568           if (AGGR_INIT_ZERO_FIRST (TREE_OPERAND (t, 1)))
2569             AGGR_INIT_ZERO_FIRST (TREE_OPERAND (u, 1)) = true;
2570         }
2571       else
2572         u = build_target_expr_with_type (TREE_OPERAND (t, 1), TREE_TYPE (t),
2573                                          tf_warning_or_error);
2574
2575       TARGET_EXPR_IMPLICIT_P (u) = TARGET_EXPR_IMPLICIT_P (t);
2576       TARGET_EXPR_LIST_INIT_P (u) = TARGET_EXPR_LIST_INIT_P (t);
2577       TARGET_EXPR_DIRECT_INIT_P (u) = TARGET_EXPR_DIRECT_INIT_P (t);
2578
2579       /* Map the old variable to the new one.  */
2580       splay_tree_insert (target_remap,
2581                          (splay_tree_key) TREE_OPERAND (t, 0),
2582                          (splay_tree_value) TREE_OPERAND (u, 0));
2583
2584       TREE_OPERAND (u, 1) = break_out_target_exprs (TREE_OPERAND (u, 1));
2585
2586       /* Replace the old expression with the new version.  */
2587       *tp = u;
2588       /* We don't have to go below this point; the recursive call to
2589          break_out_target_exprs will have handled anything below this
2590          point.  */
2591       *walk_subtrees = 0;
2592       return NULL_TREE;
2593     }
2594   if (TREE_CODE (*tp) == SAVE_EXPR)
2595     {
2596       t = *tp;
2597       splay_tree_node n = splay_tree_lookup (target_remap,
2598                                              (splay_tree_key) t);
2599       if (n)
2600         {
2601           *tp = (tree)n->value;
2602           *walk_subtrees = 0;
2603         }
2604       else
2605         {
2606           copy_tree_r (tp, walk_subtrees, NULL);
2607           splay_tree_insert (target_remap,
2608                              (splay_tree_key)t,
2609                              (splay_tree_value)*tp);
2610           /* Make sure we don't remap an already-remapped SAVE_EXPR.  */
2611           splay_tree_insert (target_remap,
2612                              (splay_tree_key)*tp,
2613                              (splay_tree_value)*tp);
2614         }
2615       return NULL_TREE;
2616     }
2617
2618   /* Make a copy of this node.  */
2619   t = copy_tree_r (tp, walk_subtrees, NULL);
2620   if (TREE_CODE (*tp) == CALL_EXPR)
2621     {
2622       set_flags_from_callee (*tp);
2623
2624       /* builtin_LINE and builtin_FILE get the location where the default
2625          argument is expanded, not where the call was written.  */
2626       tree callee = get_callee_fndecl (*tp);
2627       if (callee && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
2628         switch (DECL_FUNCTION_CODE (callee))
2629           {
2630           case BUILT_IN_FILE:
2631           case BUILT_IN_LINE:
2632             SET_EXPR_LOCATION (*tp, input_location);
2633           default:
2634             break;
2635           }
2636     }
2637   return t;
2638 }
2639
2640 /* Replace all remapped VAR_DECLs in T with their new equivalents.
2641    DATA is really a splay-tree mapping old variables to new
2642    variables.  */
2643
2644 static tree
2645 bot_replace (tree* t, int* /*walk_subtrees*/, void* data)
2646 {
2647   splay_tree target_remap = ((splay_tree) data);
2648
2649   if (VAR_P (*t))
2650     {
2651       splay_tree_node n = splay_tree_lookup (target_remap,
2652                                              (splay_tree_key) *t);
2653       if (n)
2654         *t = (tree) n->value;
2655     }
2656   else if (TREE_CODE (*t) == PARM_DECL
2657            && DECL_NAME (*t) == this_identifier
2658            && !DECL_CONTEXT (*t))
2659     {
2660       /* In an NSDMI we need to replace the 'this' parameter we used for
2661          parsing with the real one for this function.  */
2662       *t = current_class_ptr;
2663     }
2664   else if (TREE_CODE (*t) == CONVERT_EXPR
2665            && CONVERT_EXPR_VBASE_PATH (*t))
2666     {
2667       /* In an NSDMI build_base_path defers building conversions to virtual
2668          bases, and we handle it here.  */
2669       tree basetype = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (*t)));
2670       vec<tree, va_gc> *vbases = CLASSTYPE_VBASECLASSES (current_class_type);
2671       int i; tree binfo;
2672       FOR_EACH_VEC_SAFE_ELT (vbases, i, binfo)
2673         if (BINFO_TYPE (binfo) == basetype)
2674           break;
2675       *t = build_base_path (PLUS_EXPR, TREE_OPERAND (*t, 0), binfo, true,
2676                             tf_warning_or_error);
2677     }
2678
2679   return NULL_TREE;
2680 }
2681
2682 /* When we parse a default argument expression, we may create
2683    temporary variables via TARGET_EXPRs.  When we actually use the
2684    default-argument expression, we make a copy of the expression
2685    and replace the temporaries with appropriate local versions.  */
2686
2687 tree
2688 break_out_target_exprs (tree t)
2689 {
2690   static int target_remap_count;
2691   static splay_tree target_remap;
2692
2693   if (!target_remap_count++)
2694     target_remap = splay_tree_new (splay_tree_compare_pointers,
2695                                    /*splay_tree_delete_key_fn=*/NULL,
2696                                    /*splay_tree_delete_value_fn=*/NULL);
2697   cp_walk_tree (&t, bot_manip, target_remap, NULL);
2698   cp_walk_tree (&t, bot_replace, target_remap, NULL);
2699
2700   if (!--target_remap_count)
2701     {
2702       splay_tree_delete (target_remap);
2703       target_remap = NULL;
2704     }
2705
2706   return t;
2707 }
2708
2709 /* Build an expression for the subobject of OBJ at CONSTRUCTOR index INDEX,
2710    which we expect to have type TYPE.  */
2711
2712 tree
2713 build_ctor_subob_ref (tree index, tree type, tree obj)
2714 {
2715   if (index == NULL_TREE)
2716     /* Can't refer to a particular member of a vector.  */
2717     obj = NULL_TREE;
2718   else if (TREE_CODE (index) == INTEGER_CST)
2719     obj = cp_build_array_ref (input_location, obj, index, tf_none);
2720   else
2721     obj = build_class_member_access_expr (obj, index, NULL_TREE,
2722                                           /*reference*/false, tf_none);
2723   if (obj)
2724     {
2725       tree objtype = TREE_TYPE (obj);
2726       if (TREE_CODE (objtype) == ARRAY_TYPE && !TYPE_DOMAIN (objtype))
2727         {
2728           /* When the destination object refers to a flexible array member
2729              verify that it matches the type of the source object except
2730              for its domain and qualifiers.  */
2731           gcc_assert (comptypes (TYPE_MAIN_VARIANT (type),
2732                                  TYPE_MAIN_VARIANT (objtype),
2733                                  COMPARE_REDECLARATION));
2734         }
2735       else
2736         gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, objtype));
2737     }
2738
2739   return obj;
2740 }
2741
2742 struct replace_placeholders_t
2743 {
2744   tree obj;         /* The object to be substituted for a PLACEHOLDER_EXPR.  */
2745   bool seen;        /* Whether we've encountered a PLACEHOLDER_EXPR.  */
2746 };
2747
2748 /* Like substitute_placeholder_in_expr, but handle C++ tree codes and
2749    build up subexpressions as we go deeper.  */
2750
2751 static tree
2752 replace_placeholders_r (tree* t, int* walk_subtrees, void* data_)
2753 {
2754   replace_placeholders_t *d = static_cast<replace_placeholders_t*>(data_);
2755   tree obj = d->obj;
2756
2757   if (TREE_CONSTANT (*t))
2758     {
2759       *walk_subtrees = false;
2760       return NULL_TREE;
2761     }
2762
2763   switch (TREE_CODE (*t))
2764     {
2765     case PLACEHOLDER_EXPR:
2766       {
2767         tree x = obj;
2768         for (; !(same_type_ignoring_top_level_qualifiers_p
2769                  (TREE_TYPE (*t), TREE_TYPE (x)));
2770              x = TREE_OPERAND (x, 0))
2771           gcc_assert (TREE_CODE (x) == COMPONENT_REF);
2772         *t = x;
2773         *walk_subtrees = false;
2774         d->seen = true;
2775       }
2776       break;
2777
2778     case CONSTRUCTOR:
2779       {
2780         constructor_elt *ce;
2781         vec<constructor_elt,va_gc> *v = CONSTRUCTOR_ELTS (*t);
2782         for (unsigned i = 0; vec_safe_iterate (v, i, &ce); ++i)
2783           {
2784             tree *valp = &ce->value;
2785             tree type = TREE_TYPE (*valp);
2786             tree subob = obj;
2787
2788             if (TREE_CODE (*valp) == CONSTRUCTOR
2789                 && AGGREGATE_TYPE_P (type))
2790               {
2791                 /* If we're looking at the initializer for OBJ, then build
2792                    a sub-object reference.  If we're looking at an
2793                    initializer for another object, just pass OBJ down.  */
2794                 if (same_type_ignoring_top_level_qualifiers_p
2795                     (TREE_TYPE (*t), TREE_TYPE (obj)))
2796                   subob = build_ctor_subob_ref (ce->index, type, obj);
2797                 if (TREE_CODE (*valp) == TARGET_EXPR)
2798                   valp = &TARGET_EXPR_INITIAL (*valp);
2799               }
2800             d->obj = subob;
2801             cp_walk_tree (valp, replace_placeholders_r,
2802                           data_, NULL);
2803             d->obj = obj;
2804           }
2805         *walk_subtrees = false;
2806         break;
2807       }
2808
2809     default:
2810       break;
2811     }
2812
2813   return NULL_TREE;
2814 }
2815
2816 tree
2817 replace_placeholders (tree exp, tree obj, bool *seen_p)
2818 {
2819   tree *tp = &exp;
2820   replace_placeholders_t data = { obj, false };
2821   if (TREE_CODE (exp) == TARGET_EXPR)
2822     tp = &TARGET_EXPR_INITIAL (exp);
2823   cp_walk_tree (tp, replace_placeholders_r, &data, NULL);
2824   if (seen_p)
2825     *seen_p = data.seen;
2826   return exp;
2827 }
2828
2829 /* Similar to `build_nt', but for template definitions of dependent
2830    expressions  */
2831
2832 tree
2833 build_min_nt_loc (location_t loc, enum tree_code code, ...)
2834 {
2835   tree t;
2836   int length;
2837   int i;
2838   va_list p;
2839
2840   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
2841
2842   va_start (p, code);
2843
2844   t = make_node (code);
2845   SET_EXPR_LOCATION (t, loc);
2846   length = TREE_CODE_LENGTH (code);
2847
2848   for (i = 0; i < length; i++)
2849     {
2850       tree x = va_arg (p, tree);
2851       TREE_OPERAND (t, i) = x;
2852     }
2853
2854   va_end (p);
2855   return t;
2856 }
2857
2858
2859 /* Similar to `build', but for template definitions.  */
2860
2861 tree
2862 build_min (enum tree_code code, tree tt, ...)
2863 {
2864   tree t;
2865   int length;
2866   int i;
2867   va_list p;
2868
2869   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
2870
2871   va_start (p, tt);
2872
2873   t = make_node (code);
2874   length = TREE_CODE_LENGTH (code);
2875   TREE_TYPE (t) = tt;
2876
2877   for (i = 0; i < length; i++)
2878     {
2879       tree x = va_arg (p, tree);
2880       TREE_OPERAND (t, i) = x;
2881       if (x && !TYPE_P (x) && TREE_SIDE_EFFECTS (x))
2882         TREE_SIDE_EFFECTS (t) = 1;
2883     }
2884
2885   va_end (p);
2886   return t;
2887 }
2888
2889 /* Similar to `build', but for template definitions of non-dependent
2890    expressions. NON_DEP is the non-dependent expression that has been
2891    built.  */
2892
2893 tree
2894 build_min_non_dep (enum tree_code code, tree non_dep, ...)
2895 {
2896   tree t;
2897   int length;
2898   int i;
2899   va_list p;
2900
2901   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
2902
2903   va_start (p, non_dep);
2904
2905   if (REFERENCE_REF_P (non_dep))
2906     non_dep = TREE_OPERAND (non_dep, 0);
2907
2908   t = make_node (code);
2909   length = TREE_CODE_LENGTH (code);
2910   TREE_TYPE (t) = unlowered_expr_type (non_dep);
2911   TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (non_dep);
2912
2913   for (i = 0; i < length; i++)
2914     {
2915       tree x = va_arg (p, tree);
2916       TREE_OPERAND (t, i) = x;
2917     }
2918
2919   if (code == COMPOUND_EXPR && TREE_CODE (non_dep) != COMPOUND_EXPR)
2920     /* This should not be considered a COMPOUND_EXPR, because it
2921        resolves to an overload.  */
2922     COMPOUND_EXPR_OVERLOADED (t) = 1;
2923
2924   va_end (p);
2925   return convert_from_reference (t);
2926 }
2927
2928 /* Similar to `build_nt_call_vec', but for template definitions of
2929    non-dependent expressions. NON_DEP is the non-dependent expression
2930    that has been built.  */
2931
2932 tree
2933 build_min_non_dep_call_vec (tree non_dep, tree fn, vec<tree, va_gc> *argvec)
2934 {
2935   tree t = build_nt_call_vec (fn, argvec);
2936   if (REFERENCE_REF_P (non_dep))
2937     non_dep = TREE_OPERAND (non_dep, 0);
2938   TREE_TYPE (t) = TREE_TYPE (non_dep);
2939   TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (non_dep);
2940   return convert_from_reference (t);
2941 }
2942
2943 /* Similar to build_min_non_dep, but for expressions that have been resolved to
2944    a call to an operator overload.  OP is the operator that has been
2945    overloaded.  NON_DEP is the non-dependent expression that's been built,
2946    which should be a CALL_EXPR or an INDIRECT_REF to a CALL_EXPR.  OVERLOAD is
2947    the overload that NON_DEP is calling.  */
2948
2949 tree
2950 build_min_non_dep_op_overload (enum tree_code op,
2951                                tree non_dep,
2952                                tree overload, ...)
2953 {
2954   va_list p;
2955   int nargs, expected_nargs;
2956   tree fn, call;
2957   vec<tree, va_gc> *args;
2958
2959   non_dep = extract_call_expr (non_dep);
2960
2961   nargs = call_expr_nargs (non_dep);
2962
2963   expected_nargs = cp_tree_code_length (op);
2964   if ((op == POSTINCREMENT_EXPR
2965        || op == POSTDECREMENT_EXPR)
2966       /* With -fpermissive non_dep could be operator++().  */
2967       && (!flag_permissive || nargs != expected_nargs))
2968     expected_nargs += 1;
2969   gcc_assert (nargs == expected_nargs);
2970
2971   args = make_tree_vector ();
2972   va_start (p, overload);
2973
2974   if (TREE_CODE (TREE_TYPE (overload)) == FUNCTION_TYPE)
2975     {
2976       fn = overload;
2977       for (int i = 0; i < nargs; i++)
2978         {
2979           tree arg = va_arg (p, tree);
2980           vec_safe_push (args, arg);
2981         }
2982     }
2983   else if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE)
2984     {
2985       tree object = va_arg (p, tree);
2986       tree binfo = TYPE_BINFO (TREE_TYPE (object));
2987       tree method = build_baselink (binfo, binfo, overload, NULL_TREE);
2988       fn = build_min (COMPONENT_REF, TREE_TYPE (overload),
2989                       object, method, NULL_TREE);
2990       for (int i = 1; i < nargs; i++)
2991         {
2992           tree arg = va_arg (p, tree);
2993           vec_safe_push (args, arg);
2994         }
2995     }
2996   else
2997    gcc_unreachable ();
2998
2999   va_end (p);
3000   call = build_min_non_dep_call_vec (non_dep, fn, args);
3001   release_tree_vector (args);
3002
3003   tree call_expr = extract_call_expr (call);
3004   KOENIG_LOOKUP_P (call_expr) = KOENIG_LOOKUP_P (non_dep);
3005   CALL_EXPR_OPERATOR_SYNTAX (call_expr) = true;
3006   CALL_EXPR_ORDERED_ARGS (call_expr) = CALL_EXPR_ORDERED_ARGS (non_dep);
3007   CALL_EXPR_REVERSE_ARGS (call_expr) = CALL_EXPR_REVERSE_ARGS (non_dep);
3008
3009   return call;
3010 }
3011
3012 /* Return a new tree vec copied from VEC, with ELT inserted at index IDX.  */
3013
3014 vec<tree, va_gc> *
3015 vec_copy_and_insert (vec<tree, va_gc> *old_vec, tree elt, unsigned idx)
3016 {
3017   unsigned len = vec_safe_length (old_vec);
3018   gcc_assert (idx <= len);
3019
3020   vec<tree, va_gc> *new_vec = NULL;
3021   vec_alloc (new_vec, len + 1);
3022
3023   unsigned i;
3024   for (i = 0; i < len; ++i)
3025     {
3026       if (i == idx)
3027         new_vec->quick_push (elt);
3028       new_vec->quick_push ((*old_vec)[i]);
3029     }
3030   if (i == idx)
3031     new_vec->quick_push (elt);
3032
3033   return new_vec;
3034 }
3035
3036 tree
3037 get_type_decl (tree t)
3038 {
3039   if (TREE_CODE (t) == TYPE_DECL)
3040     return t;
3041   if (TYPE_P (t))
3042     return TYPE_STUB_DECL (t);
3043   gcc_assert (t == error_mark_node);
3044   return t;
3045 }
3046
3047 /* Returns the namespace that contains DECL, whether directly or
3048    indirectly.  */
3049
3050 tree
3051 decl_namespace_context (tree decl)
3052 {
3053   while (1)
3054     {
3055       if (TREE_CODE (decl) == NAMESPACE_DECL)
3056         return decl;
3057       else if (TYPE_P (decl))
3058         decl = CP_DECL_CONTEXT (TYPE_MAIN_DECL (decl));
3059       else
3060         decl = CP_DECL_CONTEXT (decl);
3061     }
3062 }
3063
3064 /* Returns true if decl is within an anonymous namespace, however deeply
3065    nested, or false otherwise.  */
3066
3067 bool
3068 decl_anon_ns_mem_p (const_tree decl)
3069 {
3070   while (1)
3071     {
3072       if (decl == NULL_TREE || decl == error_mark_node)
3073         return false;
3074       if (TREE_CODE (decl) == NAMESPACE_DECL
3075           && DECL_NAME (decl) == NULL_TREE)
3076         return true;
3077       /* Classes and namespaces inside anonymous namespaces have
3078          TREE_PUBLIC == 0, so we can shortcut the search.  */
3079       else if (TYPE_P (decl))
3080         return (TREE_PUBLIC (TYPE_MAIN_DECL (decl)) == 0);
3081       else if (TREE_CODE (decl) == NAMESPACE_DECL)
3082         return (TREE_PUBLIC (decl) == 0);
3083       else
3084         decl = DECL_CONTEXT (decl);
3085     }
3086 }
3087
3088 /* Subroutine of cp_tree_equal: t1 and t2 are the CALL_EXPR_FNs of two
3089    CALL_EXPRS.  Return whether they are equivalent.  */
3090
3091 static bool
3092 called_fns_equal (tree t1, tree t2)
3093 {
3094   /* Core 1321: dependent names are equivalent even if the overload sets
3095      are different.  But do compare explicit template arguments.  */
3096   tree name1 = dependent_name (t1);
3097   tree name2 = dependent_name (t2);
3098   if (name1 || name2)
3099     {
3100       tree targs1 = NULL_TREE, targs2 = NULL_TREE;
3101
3102       if (name1 != name2)
3103         return false;
3104
3105       if (TREE_CODE (t1) == TEMPLATE_ID_EXPR)
3106         targs1 = TREE_OPERAND (t1, 1);
3107       if (TREE_CODE (t2) == TEMPLATE_ID_EXPR)
3108         targs2 = TREE_OPERAND (t2, 1);
3109       return cp_tree_equal (targs1, targs2);
3110     }
3111   else
3112     return cp_tree_equal (t1, t2);
3113 }
3114
3115 /* Return truthvalue of whether T1 is the same tree structure as T2.
3116    Return 1 if they are the same. Return 0 if they are different.  */
3117
3118 bool
3119 cp_tree_equal (tree t1, tree t2)
3120 {
3121   enum tree_code code1, code2;
3122
3123   if (t1 == t2)
3124     return true;
3125   if (!t1 || !t2)
3126     return false;
3127
3128   code1 = TREE_CODE (t1);
3129   code2 = TREE_CODE (t2);
3130
3131   if (code1 != code2)
3132     return false;
3133
3134   switch (code1)
3135     {
3136     case VOID_CST:
3137       /* There's only a single VOID_CST node, so we should never reach
3138          here.  */
3139       gcc_unreachable ();
3140
3141     case INTEGER_CST:
3142       return tree_int_cst_equal (t1, t2);
3143
3144     case REAL_CST:
3145       return real_equal (&TREE_REAL_CST (t1), &TREE_REAL_CST (t2));
3146
3147     case STRING_CST:
3148       return TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
3149         && !memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
3150                     TREE_STRING_LENGTH (t1));
3151
3152     case FIXED_CST:
3153       return FIXED_VALUES_IDENTICAL (TREE_FIXED_CST (t1),
3154                                      TREE_FIXED_CST (t2));
3155
3156     case COMPLEX_CST:
3157       return cp_tree_equal (TREE_REALPART (t1), TREE_REALPART (t2))
3158         && cp_tree_equal (TREE_IMAGPART (t1), TREE_IMAGPART (t2));
3159
3160     case VECTOR_CST:
3161       return operand_equal_p (t1, t2, OEP_ONLY_CONST);
3162
3163     case CONSTRUCTOR:
3164       /* We need to do this when determining whether or not two
3165          non-type pointer to member function template arguments
3166          are the same.  */
3167       if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))
3168           || CONSTRUCTOR_NELTS (t1) != CONSTRUCTOR_NELTS (t2))
3169         return false;
3170       {
3171         tree field, value;
3172         unsigned int i;
3173         FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t1), i, field, value)
3174           {
3175             constructor_elt *elt2 = CONSTRUCTOR_ELT (t2, i);
3176             if (!cp_tree_equal (field, elt2->index)
3177                 || !cp_tree_equal (value, elt2->value))
3178               return false;
3179           }
3180       }
3181       return true;
3182
3183     case TREE_LIST:
3184       if (!cp_tree_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2)))
3185         return false;
3186       if (!cp_tree_equal (TREE_VALUE (t1), TREE_VALUE (t2)))
3187         return false;
3188       return cp_tree_equal (TREE_CHAIN (t1), TREE_CHAIN (t2));
3189
3190     case SAVE_EXPR:
3191       return cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
3192
3193     case CALL_EXPR:
3194       {
3195         tree arg1, arg2;
3196         call_expr_arg_iterator iter1, iter2;
3197         if (!called_fns_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
3198           return false;
3199         for (arg1 = first_call_expr_arg (t1, &iter1),
3200                arg2 = first_call_expr_arg (t2, &iter2);
3201              arg1 && arg2;
3202              arg1 = next_call_expr_arg (&iter1),
3203                arg2 = next_call_expr_arg (&iter2))
3204           if (!cp_tree_equal (arg1, arg2))
3205             return false;
3206         if (arg1 || arg2)
3207           return false;
3208         return true;
3209       }
3210
3211     case TARGET_EXPR:
3212       {
3213         tree o1 = TREE_OPERAND (t1, 0);
3214         tree o2 = TREE_OPERAND (t2, 0);
3215
3216         /* Special case: if either target is an unallocated VAR_DECL,
3217            it means that it's going to be unified with whatever the
3218            TARGET_EXPR is really supposed to initialize, so treat it
3219            as being equivalent to anything.  */
3220         if (VAR_P (o1) && DECL_NAME (o1) == NULL_TREE
3221             && !DECL_RTL_SET_P (o1))
3222           /*Nop*/;
3223         else if (VAR_P (o2) && DECL_NAME (o2) == NULL_TREE
3224                  && !DECL_RTL_SET_P (o2))
3225           /*Nop*/;
3226         else if (!cp_tree_equal (o1, o2))
3227           return false;
3228
3229         return cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
3230       }
3231
3232     case WITH_CLEANUP_EXPR:
3233       if (!cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0)))
3234         return false;
3235       return cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t1, 1));
3236
3237     case COMPONENT_REF:
3238       if (TREE_OPERAND (t1, 1) != TREE_OPERAND (t2, 1))
3239         return false;
3240       return cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
3241
3242     case PARM_DECL:
3243       /* For comparing uses of parameters in late-specified return types
3244          with an out-of-class definition of the function, but can also come
3245          up for expressions that involve 'this' in a member function
3246          template.  */
3247
3248       if (comparing_specializations && !CONSTRAINT_VAR_P (t1))
3249         /* When comparing hash table entries, only an exact match is
3250            good enough; we don't want to replace 'this' with the
3251            version from another function.  But be more flexible
3252            with local parameters in a requires-expression.  */
3253         return false;
3254
3255       if (same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
3256         {
3257           if (DECL_ARTIFICIAL (t1) ^ DECL_ARTIFICIAL (t2))
3258             return false;
3259           if (CONSTRAINT_VAR_P (t1) ^ CONSTRAINT_VAR_P (t2))
3260             return false;
3261           if (DECL_ARTIFICIAL (t1)
3262               || (DECL_PARM_LEVEL (t1) == DECL_PARM_LEVEL (t2)
3263                   && DECL_PARM_INDEX (t1) == DECL_PARM_INDEX (t2)))
3264             return true;
3265         }
3266       return false;
3267
3268     case VAR_DECL:
3269     case CONST_DECL:
3270     case FIELD_DECL:
3271     case FUNCTION_DECL:
3272     case TEMPLATE_DECL:
3273     case IDENTIFIER_NODE:
3274     case SSA_NAME:
3275       return false;
3276
3277     case BASELINK:
3278       return (BASELINK_BINFO (t1) == BASELINK_BINFO (t2)
3279               && BASELINK_ACCESS_BINFO (t1) == BASELINK_ACCESS_BINFO (t2)
3280               && BASELINK_QUALIFIED_P (t1) == BASELINK_QUALIFIED_P (t2)
3281               && cp_tree_equal (BASELINK_FUNCTIONS (t1),
3282                                 BASELINK_FUNCTIONS (t2)));
3283
3284     case TEMPLATE_PARM_INDEX:
3285       return (TEMPLATE_PARM_IDX (t1) == TEMPLATE_PARM_IDX (t2)
3286               && TEMPLATE_PARM_LEVEL (t1) == TEMPLATE_PARM_LEVEL (t2)
3287               && (TEMPLATE_PARM_PARAMETER_PACK (t1)
3288                   == TEMPLATE_PARM_PARAMETER_PACK (t2))
3289               && same_type_p (TREE_TYPE (TEMPLATE_PARM_DECL (t1)),
3290                               TREE_TYPE (TEMPLATE_PARM_DECL (t2))));
3291
3292     case TEMPLATE_ID_EXPR:
3293       return (cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0))
3294               && cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1)));
3295
3296     case CONSTRAINT_INFO:
3297       return cp_tree_equal (CI_ASSOCIATED_CONSTRAINTS (t1),
3298                             CI_ASSOCIATED_CONSTRAINTS (t2));
3299
3300     case CHECK_CONSTR:
3301       return (CHECK_CONSTR_CONCEPT (t1) == CHECK_CONSTR_CONCEPT (t2)
3302               && comp_template_args (CHECK_CONSTR_ARGS (t1),
3303                                      CHECK_CONSTR_ARGS (t2)));
3304
3305     case TREE_VEC:
3306       {
3307         unsigned ix;
3308         if (TREE_VEC_LENGTH (t1) != TREE_VEC_LENGTH (t2))
3309           return false;
3310         for (ix = TREE_VEC_LENGTH (t1); ix--;)
3311           if (!cp_tree_equal (TREE_VEC_ELT (t1, ix),
3312                               TREE_VEC_ELT (t2, ix)))
3313             return false;
3314         return true;
3315       }
3316
3317     case SIZEOF_EXPR:
3318     case ALIGNOF_EXPR:
3319       {
3320         tree o1 = TREE_OPERAND (t1, 0);
3321         tree o2 = TREE_OPERAND (t2, 0);
3322
3323         if (code1 == SIZEOF_EXPR)
3324           {
3325             if (SIZEOF_EXPR_TYPE_P (t1))
3326               o1 = TREE_TYPE (o1);
3327             if (SIZEOF_EXPR_TYPE_P (t2))
3328               o2 = TREE_TYPE (o2);
3329           }
3330         if (TREE_CODE (o1) != TREE_CODE (o2))
3331           return false;
3332         if (TYPE_P (o1))
3333           return same_type_p (o1, o2);
3334         else
3335           return cp_tree_equal (o1, o2);
3336       }
3337
3338     case MODOP_EXPR:
3339       {
3340         tree t1_op1, t2_op1;
3341
3342         if (!cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0)))
3343           return false;
3344
3345         t1_op1 = TREE_OPERAND (t1, 1);
3346         t2_op1 = TREE_OPERAND (t2, 1);
3347         if (TREE_CODE (t1_op1) != TREE_CODE (t2_op1))
3348           return false;
3349
3350         return cp_tree_equal (TREE_OPERAND (t1, 2), TREE_OPERAND (t2, 2));
3351       }
3352
3353     case PTRMEM_CST:
3354       /* Two pointer-to-members are the same if they point to the same
3355          field or function in the same class.  */
3356       if (PTRMEM_CST_MEMBER (t1) != PTRMEM_CST_MEMBER (t2))
3357         return false;
3358
3359       return same_type_p (PTRMEM_CST_CLASS (t1), PTRMEM_CST_CLASS (t2));
3360
3361     case OVERLOAD:
3362       if (OVL_FUNCTION (t1) != OVL_FUNCTION (t2))
3363         return false;
3364       return cp_tree_equal (OVL_CHAIN (t1), OVL_CHAIN (t2));
3365
3366     case TRAIT_EXPR:
3367       if (TRAIT_EXPR_KIND (t1) != TRAIT_EXPR_KIND (t2))
3368         return false;
3369       return same_type_p (TRAIT_EXPR_TYPE1 (t1), TRAIT_EXPR_TYPE1 (t2))
3370         && cp_tree_equal (TRAIT_EXPR_TYPE2 (t1), TRAIT_EXPR_TYPE2 (t2));
3371
3372     case CAST_EXPR:
3373     case STATIC_CAST_EXPR:
3374     case REINTERPRET_CAST_EXPR:
3375     case CONST_CAST_EXPR:
3376     case DYNAMIC_CAST_EXPR:
3377     case IMPLICIT_CONV_EXPR:
3378     case NEW_EXPR:
3379     CASE_CONVERT:
3380     case NON_LVALUE_EXPR:
3381     case VIEW_CONVERT_EXPR:
3382       if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
3383         return false;
3384       /* Now compare operands as usual.  */
3385       break;
3386
3387     case DEFERRED_NOEXCEPT:
3388       return (cp_tree_equal (DEFERRED_NOEXCEPT_PATTERN (t1),
3389                              DEFERRED_NOEXCEPT_PATTERN (t2))
3390               && comp_template_args (DEFERRED_NOEXCEPT_ARGS (t1),
3391                                      DEFERRED_NOEXCEPT_ARGS (t2)));
3392       break;
3393
3394     default:
3395       break;
3396     }
3397
3398   switch (TREE_CODE_CLASS (code1))
3399     {
3400     case tcc_unary:
3401     case tcc_binary:
3402     case tcc_comparison:
3403     case tcc_expression:
3404     case tcc_vl_exp:
3405     case tcc_reference:
3406     case tcc_statement:
3407       {
3408         int i, n;
3409
3410         n = cp_tree_operand_length (t1);
3411         if (TREE_CODE_CLASS (code1) == tcc_vl_exp
3412             && n != TREE_OPERAND_LENGTH (t2))
3413           return false;
3414
3415         for (i = 0; i < n; ++i)
3416           if (!cp_tree_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i)))
3417             return false;
3418
3419         return true;
3420       }
3421
3422     case tcc_type:
3423       return same_type_p (t1, t2);
3424     default:
3425       gcc_unreachable ();
3426     }
3427   /* We can get here with --disable-checking.  */
3428   return false;
3429 }
3430
3431 /* The type of ARG when used as an lvalue.  */
3432
3433 tree
3434 lvalue_type (tree arg)
3435 {
3436   tree type = TREE_TYPE (arg);
3437   return type;
3438 }
3439
3440 /* The type of ARG for printing error messages; denote lvalues with
3441    reference types.  */
3442
3443 tree
3444 error_type (tree arg)
3445 {
3446   tree type = TREE_TYPE (arg);
3447
3448   if (TREE_CODE (type) == ARRAY_TYPE)
3449     ;
3450   else if (TREE_CODE (type) == ERROR_MARK)
3451     ;
3452   else if (lvalue_p (arg))
3453     type = build_reference_type (lvalue_type (arg));
3454   else if (MAYBE_CLASS_TYPE_P (type))
3455     type = lvalue_type (arg);
3456
3457   return type;
3458 }
3459
3460 /* Does FUNCTION use a variable-length argument list?  */
3461
3462 int
3463 varargs_function_p (const_tree function)
3464 {
3465   return stdarg_p (TREE_TYPE (function));
3466 }
3467
3468 /* Returns 1 if decl is a member of a class.  */
3469
3470 int
3471 member_p (const_tree decl)
3472 {
3473   const_tree const ctx = DECL_CONTEXT (decl);
3474   return (ctx && TYPE_P (ctx));
3475 }
3476
3477 /* Create a placeholder for member access where we don't actually have an
3478    object that the access is against.  */
3479
3480 tree
3481 build_dummy_object (tree type)
3482 {
3483   tree decl = build1 (CONVERT_EXPR, build_pointer_type (type), void_node);
3484   return cp_build_indirect_ref (decl, RO_NULL, tf_warning_or_error);
3485 }
3486
3487 /* We've gotten a reference to a member of TYPE.  Return *this if appropriate,
3488    or a dummy object otherwise.  If BINFOP is non-0, it is filled with the
3489    binfo path from current_class_type to TYPE, or 0.  */
3490
3491 tree
3492 maybe_dummy_object (tree type, tree* binfop)
3493 {
3494   tree decl, context;
3495   tree binfo;
3496   tree current = current_nonlambda_class_type ();
3497
3498   if (current
3499       && (binfo = lookup_base (current, type, ba_any, NULL,
3500                                tf_warning_or_error)))
3501     context = current;
3502   else
3503     {
3504       /* Reference from a nested class member function.  */
3505       context = type;
3506       binfo = TYPE_BINFO (type);
3507     }
3508
3509   if (binfop)
3510     *binfop = binfo;
3511
3512   if (current_class_ref
3513       /* current_class_ref might not correspond to current_class_type if
3514          we're in tsubst_default_argument or a lambda-declarator; in either
3515          case, we want to use current_class_ref if it matches CONTEXT.  */
3516       && (same_type_ignoring_top_level_qualifiers_p
3517           (TREE_TYPE (current_class_ref), context)))
3518     decl = current_class_ref;
3519   else
3520     decl = build_dummy_object (context);
3521
3522   return decl;
3523 }
3524
3525 /* Returns 1 if OB is a placeholder object, or a pointer to one.  */
3526
3527 int
3528 is_dummy_object (const_tree ob)
3529 {
3530   if (INDIRECT_REF_P (ob))
3531     ob = TREE_OPERAND (ob, 0);
3532   return (TREE_CODE (ob) == CONVERT_EXPR
3533           && TREE_OPERAND (ob, 0) == void_node);
3534 }
3535
3536 /* Returns 1 iff type T is something we want to treat as a scalar type for
3537    the purpose of deciding whether it is trivial/POD/standard-layout.  */
3538
3539 bool
3540 scalarish_type_p (const_tree t)
3541 {
3542   if (t == error_mark_node)
3543     return 1;
3544
3545   return (SCALAR_TYPE_P (t) || VECTOR_TYPE_P (t));
3546 }
3547
3548 /* Returns true iff T requires non-trivial default initialization.  */
3549
3550 bool
3551 type_has_nontrivial_default_init (const_tree t)
3552 {
3553   t = strip_array_types (CONST_CAST_TREE (t));
3554
3555   if (CLASS_TYPE_P (t))
3556     return TYPE_HAS_COMPLEX_DFLT (t);
3557   else
3558     return 0;
3559 }
3560
3561 /* Returns true iff copying an object of type T (including via move
3562    constructor) is non-trivial.  That is, T has no non-trivial copy
3563    constructors and no non-trivial move constructors.  */
3564
3565 bool
3566 type_has_nontrivial_copy_init (const_tree t)
3567 {
3568   t = strip_array_types (CONST_CAST_TREE (t));
3569
3570   if (CLASS_TYPE_P (t))
3571     {
3572       gcc_assert (COMPLETE_TYPE_P (t));
3573       return ((TYPE_HAS_COPY_CTOR (t)
3574                && TYPE_HAS_COMPLEX_COPY_CTOR (t))
3575               || TYPE_HAS_COMPLEX_MOVE_CTOR (t));
3576     }
3577   else
3578     return 0;
3579 }
3580
3581 /* Returns 1 iff type T is a trivially copyable type, as defined in
3582    [basic.types] and [class].  */
3583
3584 bool
3585 trivially_copyable_p (const_tree t)
3586 {
3587   t = strip_array_types (CONST_CAST_TREE (t));
3588
3589   if (CLASS_TYPE_P (t))
3590     return ((!TYPE_HAS_COPY_CTOR (t)
3591              || !TYPE_HAS_COMPLEX_COPY_CTOR (t))
3592             && !TYPE_HAS_COMPLEX_MOVE_CTOR (t)
3593             && (!TYPE_HAS_COPY_ASSIGN (t)
3594                 || !TYPE_HAS_COMPLEX_COPY_ASSIGN (t))
3595             && !TYPE_HAS_COMPLEX_MOVE_ASSIGN (t)
3596             && TYPE_HAS_TRIVIAL_DESTRUCTOR (t));
3597   else
3598     return !CP_TYPE_VOLATILE_P (t) && scalarish_type_p (t);
3599 }
3600
3601 /* Returns 1 iff type T is a trivial type, as defined in [basic.types] and
3602    [class].  */
3603
3604 bool
3605 trivial_type_p (const_tree t)
3606 {
3607   t = strip_array_types (CONST_CAST_TREE (t));
3608
3609   if (CLASS_TYPE_P (t))
3610     return (TYPE_HAS_TRIVIAL_DFLT (t)
3611             && trivially_copyable_p (t));
3612   else
3613     return scalarish_type_p (t);
3614 }
3615
3616 /* Returns 1 iff type T is a POD type, as defined in [basic.types].  */
3617
3618 bool
3619 pod_type_p (const_tree t)
3620 {
3621   /* This CONST_CAST is okay because strip_array_types returns its
3622      argument unmodified and we assign it to a const_tree.  */
3623   t = strip_array_types (CONST_CAST_TREE(t));
3624
3625   if (!CLASS_TYPE_P (t))
3626     return scalarish_type_p (t);
3627   else if (cxx_dialect > cxx98)
3628     /* [class]/10: A POD struct is a class that is both a trivial class and a
3629        standard-layout class, and has no non-static data members of type
3630        non-POD struct, non-POD union (or array of such types).
3631
3632        We don't need to check individual members because if a member is
3633        non-std-layout or non-trivial, the class will be too.  */
3634     return (std_layout_type_p (t) && trivial_type_p (t));
3635   else
3636     /* The C++98 definition of POD is different.  */
3637     return !CLASSTYPE_NON_LAYOUT_POD_P (t);
3638 }
3639
3640 /* Returns true iff T is POD for the purpose of layout, as defined in the
3641    C++ ABI.  */
3642
3643 bool
3644 layout_pod_type_p (const_tree t)
3645 {
3646   t = strip_array_types (CONST_CAST_TREE (t));
3647
3648   if (CLASS_TYPE_P (t))
3649     return !CLASSTYPE_NON_LAYOUT_POD_P (t);
3650   else
3651     return scalarish_type_p (t);
3652 }
3653
3654 /* Returns true iff T is a standard-layout type, as defined in
3655    [basic.types].  */
3656
3657 bool
3658 std_layout_type_p (const_tree t)
3659 {
3660   t = strip_array_types (CONST_CAST_TREE (t));
3661
3662   if (CLASS_TYPE_P (t))
3663     return !CLASSTYPE_NON_STD_LAYOUT (t);
3664   else
3665     return scalarish_type_p (t);
3666 }
3667
3668 static bool record_has_unique_obj_representations (const_tree, const_tree);
3669
3670 /* Returns true iff T satisfies std::has_unique_object_representations<T>,
3671    as defined in [meta.unary.prop].  */
3672
3673 bool
3674 type_has_unique_obj_representations (const_tree t)
3675 {
3676   bool ret;
3677
3678   t = strip_array_types (CONST_CAST_TREE (t));
3679
3680   if (!trivially_copyable_p (t))
3681     return false;
3682
3683   if (CLASS_TYPE_P (t) && CLASSTYPE_UNIQUE_OBJ_REPRESENTATIONS_SET (t))
3684     return CLASSTYPE_UNIQUE_OBJ_REPRESENTATIONS (t);
3685
3686   switch (TREE_CODE (t))
3687     {
3688     case INTEGER_TYPE:
3689     case POINTER_TYPE:
3690     case REFERENCE_TYPE:
3691       /* If some backend has any paddings in these types, we should add
3692          a target hook for this and handle it there.  */
3693       return true;
3694
3695     case BOOLEAN_TYPE:
3696       /* For bool values other than 0 and 1 should only appear with
3697          undefined behavior.  */
3698       return true;
3699
3700     case ENUMERAL_TYPE:
3701       return type_has_unique_obj_representations (ENUM_UNDERLYING_TYPE (t));
3702
3703     case REAL_TYPE:
3704       /* XFmode certainly contains padding on x86, which the CPU doesn't store
3705          when storing long double values, so for that we have to return false.
3706          Other kinds of floating point values are questionable due to +.0/-.0
3707          and NaNs, let's play safe for now.  */
3708       return false;
3709
3710     case FIXED_POINT_TYPE:
3711       return false;
3712
3713     case OFFSET_TYPE:
3714       return true;
3715
3716     case COMPLEX_TYPE:
3717     case VECTOR_TYPE:
3718       return type_has_unique_obj_representations (TREE_TYPE (t));
3719
3720     case RECORD_TYPE:
3721       ret = record_has_unique_obj_representations (t, TYPE_SIZE (t));
3722       if (CLASS_TYPE_P (t))
3723         {
3724           CLASSTYPE_UNIQUE_OBJ_REPRESENTATIONS_SET (t) = 1;
3725           CLASSTYPE_UNIQUE_OBJ_REPRESENTATIONS (t) = ret;
3726         }
3727       return ret;
3728
3729     case UNION_TYPE:
3730       ret = true;
3731       bool any_fields;
3732       any_fields = false;
3733       for (tree field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
3734         if (TREE_CODE (field) == FIELD_DECL)
3735           {
3736             any_fields = true;
3737             if (!type_has_unique_obj_representations (TREE_TYPE (field))
3738                 || simple_cst_equal (DECL_SIZE (field), TYPE_SIZE (t)) != 1)
3739               {
3740                 ret = false;
3741                 break;
3742               }
3743           }
3744       if (!any_fields && !integer_zerop (TYPE_SIZE (t)))
3745         ret = false;
3746       if (CLASS_TYPE_P (t))
3747         {
3748           CLASSTYPE_UNIQUE_OBJ_REPRESENTATIONS_SET (t) = 1;
3749           CLASSTYPE_UNIQUE_OBJ_REPRESENTATIONS (t) = ret;
3750         }
3751       return ret;
3752
3753     case NULLPTR_TYPE:
3754       return false;
3755
3756     case ERROR_MARK:
3757       return false;
3758
3759     default:
3760       gcc_unreachable ();
3761     }
3762 }
3763
3764 /* Helper function for type_has_unique_obj_representations.  */
3765
3766 static bool
3767 record_has_unique_obj_representations (const_tree t, const_tree sz)
3768 {
3769   for (tree field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
3770     if (TREE_CODE (field) != FIELD_DECL)
3771       ;
3772     /* For bases, can't use type_has_unique_obj_representations here, as in
3773         struct S { int i : 24; S (); };
3774         struct T : public S { int j : 8; T (); };
3775         S doesn't have unique obj representations, but T does.  */
3776     else if (DECL_FIELD_IS_BASE (field))
3777       {
3778         if (!record_has_unique_obj_representations (TREE_TYPE (field),
3779                                                     DECL_SIZE (field)))
3780           return false;
3781       }
3782     else if (DECL_C_BIT_FIELD (field))
3783       {
3784         tree btype = DECL_BIT_FIELD_TYPE (field);
3785         if (!type_has_unique_obj_representations (btype))
3786           return false;
3787       }
3788     else if (!type_has_unique_obj_representations (TREE_TYPE (field)))
3789       return false;
3790
3791   offset_int cur = 0;
3792   for (tree field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
3793     if (TREE_CODE (field) == FIELD_DECL)
3794       {
3795         offset_int fld = wi::to_offset (DECL_FIELD_OFFSET (field));
3796         offset_int bitpos = wi::to_offset (DECL_FIELD_BIT_OFFSET (field));
3797         fld = fld * BITS_PER_UNIT + bitpos;
3798         if (cur != fld)
3799           return false;
3800         if (DECL_SIZE (field))
3801           {
3802             offset_int size = wi::to_offset (DECL_SIZE (field));
3803             cur += size;
3804           }
3805       }
3806   if (cur != wi::to_offset (sz))
3807     return false;
3808
3809   return true;
3810 }
3811
3812 /* Nonzero iff type T is a class template implicit specialization.  */
3813
3814 bool
3815 class_tmpl_impl_spec_p (const_tree t)
3816 {
3817   return CLASS_TYPE_P (t) && CLASSTYPE_TEMPLATE_INSTANTIATION (t);
3818 }
3819
3820 /* Returns 1 iff zero initialization of type T means actually storing
3821    zeros in it.  */
3822
3823 int
3824 zero_init_p (const_tree t)
3825 {
3826   /* This CONST_CAST is okay because strip_array_types returns its
3827      argument unmodified and we assign it to a const_tree.  */
3828   t = strip_array_types (CONST_CAST_TREE(t));
3829
3830   if (t == error_mark_node)
3831     return 1;
3832
3833   /* NULL pointers to data members are initialized with -1.  */
3834   if (TYPE_PTRDATAMEM_P (t))
3835     return 0;
3836
3837   /* Classes that contain types that can't be zero-initialized, cannot
3838      be zero-initialized themselves.  */
3839   if (CLASS_TYPE_P (t) && CLASSTYPE_NON_ZERO_INIT_P (t))
3840     return 0;
3841
3842   return 1;
3843 }
3844
3845 /* Handle the C++17 [[nodiscard]] attribute, which is similar to the GNU
3846    warn_unused_result attribute.  */
3847
3848 static tree
3849 handle_nodiscard_attribute (tree *node, tree name, tree /*args*/,
3850                             int /*flags*/, bool *no_add_attrs)
3851 {
3852   if (TREE_CODE (*node) == FUNCTION_DECL)
3853     {
3854       if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (*node))))
3855         warning (OPT_Wattributes, "%qE attribute applied to %qD with void "
3856                  "return type", name, *node);
3857     }
3858   else if (OVERLOAD_TYPE_P (*node))
3859     /* OK */;
3860   else
3861     {
3862       warning (OPT_Wattributes, "%qE attribute can only be applied to "
3863                "functions or to class or enumeration types", name);
3864       *no_add_attrs = true;
3865     }
3866   return NULL_TREE;
3867 }
3868
3869 /* Table of valid C++ attributes.  */
3870 const struct attribute_spec cxx_attribute_table[] =
3871 {
3872   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler,
3873        affects_type_identity } */
3874   { "init_priority",  1, 1, true,  false, false,
3875     handle_init_priority_attribute, false },
3876   { "abi_tag", 1, -1, false, false, false,
3877     handle_abi_tag_attribute, true },
3878   { NULL,             0, 0, false, false, false, NULL, false }
3879 };
3880
3881 /* Table of C++ standard attributes.  */
3882 const struct attribute_spec std_attribute_table[] =
3883 {
3884   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler,
3885        affects_type_identity } */
3886   { "maybe_unused", 0, 0, false, false, false,
3887     handle_unused_attribute, false },
3888   { "nodiscard", 0, 0, false, false, false,
3889     handle_nodiscard_attribute, false },
3890   { NULL,             0, 0, false, false, false, NULL, false }
3891 };
3892
3893 /* Handle an "init_priority" attribute; arguments as in
3894    struct attribute_spec.handler.  */
3895 static tree
3896 handle_init_priority_attribute (tree* node,
3897                                 tree name,
3898                                 tree args,
3899                                 int /*flags*/,
3900                                 bool* no_add_attrs)
3901 {
3902   tree initp_expr = TREE_VALUE (args);
3903   tree decl = *node;
3904   tree type = TREE_TYPE (decl);
3905   int pri;
3906
3907   STRIP_NOPS (initp_expr);
3908   initp_expr = default_conversion (initp_expr);
3909   if (initp_expr)
3910     initp_expr = maybe_constant_value (initp_expr);
3911
3912   if (!initp_expr || TREE_CODE (initp_expr) != INTEGER_CST)
3913     {
3914       error ("requested init_priority is not an integer constant");
3915       cxx_constant_value (initp_expr);
3916       *no_add_attrs = true;
3917       return NULL_TREE;
3918     }
3919
3920   pri = TREE_INT_CST_LOW (initp_expr);
3921
3922   type = strip_array_types (type);
3923
3924   if (decl == NULL_TREE
3925       || !VAR_P (decl)
3926       || !TREE_STATIC (decl)
3927       || DECL_EXTERNAL (decl)
3928       || (TREE_CODE (type) != RECORD_TYPE
3929           && TREE_CODE (type) != UNION_TYPE)
3930       /* Static objects in functions are initialized the
3931          first time control passes through that
3932          function. This is not precise enough to pin down an
3933          init_priority value, so don't allow it.  */
3934       || current_function_decl)
3935     {
3936       error ("can only use %qE attribute on file-scope definitions "
3937              "of objects of class type", name);
3938       *no_add_attrs = true;
3939       return NULL_TREE;
3940     }
3941
3942   if (pri > MAX_INIT_PRIORITY || pri <= 0)
3943     {
3944       error ("requested init_priority is out of range");
3945       *no_add_attrs = true;
3946       return NULL_TREE;
3947     }
3948
3949   /* Check for init_priorities that are reserved for
3950      language and runtime support implementations.*/
3951   if (pri <= MAX_RESERVED_INIT_PRIORITY)
3952     {
3953       warning
3954         (0, "requested init_priority is reserved for internal use");
3955     }
3956
3957   if (SUPPORTS_INIT_PRIORITY)
3958     {
3959       SET_DECL_INIT_PRIORITY (decl, pri);
3960       DECL_HAS_INIT_PRIORITY_P (decl) = 1;
3961       return NULL_TREE;
3962     }
3963   else
3964     {
3965       error ("%qE attribute is not supported on this platform", name);
3966       *no_add_attrs = true;
3967       return NULL_TREE;
3968     }
3969 }
3970
3971 /* DECL is being redeclared; the old declaration had the abi tags in OLD,
3972    and the new one has the tags in NEW_.  Give an error if there are tags
3973    in NEW_ that weren't in OLD.  */
3974
3975 bool
3976 check_abi_tag_redeclaration (const_tree decl, const_tree old, const_tree new_)
3977 {
3978   if (old && TREE_CODE (TREE_VALUE (old)) == TREE_LIST)
3979     old = TREE_VALUE (old);
3980   if (new_ && TREE_CODE (TREE_VALUE (new_)) == TREE_LIST)
3981     new_ = TREE_VALUE (new_);
3982   bool err = false;
3983   for (const_tree t = new_; t; t = TREE_CHAIN (t))
3984     {
3985       tree str = TREE_VALUE (t);
3986       for (const_tree in = old; in; in = TREE_CHAIN (in))
3987         {
3988           tree ostr = TREE_VALUE (in);
3989           if (cp_tree_equal (str, ostr))
3990             goto found;
3991         }
3992       error ("redeclaration of %qD adds abi tag %E", decl, str);
3993       err = true;
3994     found:;
3995     }
3996   if (err)
3997     {
3998       inform (DECL_SOURCE_LOCATION (decl), "previous declaration here");
3999       return false;
4000     }
4001   return true;
4002 }
4003
4004 /* The abi_tag attribute with the name NAME was given ARGS.  If they are
4005    ill-formed, give an error and return false; otherwise, return true.  */
4006
4007 bool
4008 check_abi_tag_args (tree args, tree name)
4009 {
4010   if (!args)
4011     {
4012       error ("the %qE attribute requires arguments", name);
4013       return false;
4014     }
4015   for (tree arg = args; arg; arg = TREE_CHAIN (arg))
4016     {
4017       tree elt = TREE_VALUE (arg);
4018       if (TREE_CODE (elt) != STRING_CST
4019           || (!same_type_ignoring_top_level_qualifiers_p
4020               (strip_array_types (TREE_TYPE (elt)),
4021                char_type_node)))
4022         {
4023           error ("arguments to the %qE attribute must be narrow string "
4024                  "literals", name);
4025           return false;
4026         }
4027       const char *begin = TREE_STRING_POINTER (elt);
4028       const char *end = begin + TREE_STRING_LENGTH (elt);
4029       for (const char *p = begin; p != end; ++p)
4030         {
4031           char c = *p;
4032           if (p == begin)
4033             {
4034               if (!ISALPHA (c) && c != '_')
4035                 {
4036                   error ("arguments to the %qE attribute must contain valid "
4037                          "identifiers", name);
4038                   inform (input_location, "%<%c%> is not a valid first "
4039                           "character for an identifier", c);
4040                   return false;
4041                 }
4042             }
4043           else if (p == end - 1)
4044             gcc_assert (c == 0);
4045           else
4046             {
4047               if (!ISALNUM (c) && c != '_')
4048                 {
4049                   error ("arguments to the %qE attribute must contain valid "
4050                          "identifiers", name);
4051                   inform (input_location, "%<%c%> is not a valid character "
4052                           "in an identifier", c);
4053                   return false;
4054                 }
4055             }
4056         }
4057     }
4058   return true;
4059 }
4060
4061 /* Handle an "abi_tag" attribute; arguments as in
4062    struct attribute_spec.handler.  */
4063
4064 static tree
4065 handle_abi_tag_attribute (tree* node, tree name, tree args,
4066                           int flags, bool* no_add_attrs)
4067 {
4068   if (!check_abi_tag_args (args, name))
4069     goto fail;
4070
4071   if (TYPE_P (*node))
4072     {
4073       if (!OVERLOAD_TYPE_P (*node))
4074         {
4075           error ("%qE attribute applied to non-class, non-enum type %qT",
4076                  name, *node);
4077           goto fail;
4078         }
4079       else if (!(flags & (int)ATTR_FLAG_TYPE_IN_PLACE))
4080         {
4081           error ("%qE attribute applied to %qT after its definition",
4082                  name, *node);
4083           goto fail;
4084         }
4085       else if (CLASS_TYPE_P (*node)
4086                && CLASSTYPE_TEMPLATE_INSTANTIATION (*node))
4087         {
4088           warning (OPT_Wattributes, "ignoring %qE attribute applied to "
4089                    "template instantiation %qT", name, *node);
4090           goto fail;
4091         }
4092       else if (CLASS_TYPE_P (*node)
4093                && CLASSTYPE_TEMPLATE_SPECIALIZATION (*node))
4094         {
4095           warning (OPT_Wattributes, "ignoring %qE attribute applied to "
4096                    "template specialization %qT", name, *node);
4097           goto fail;
4098         }
4099
4100       tree attributes = TYPE_ATTRIBUTES (*node);
4101       tree decl = TYPE_NAME (*node);
4102
4103       /* Make sure all declarations have the same abi tags.  */
4104       if (DECL_SOURCE_LOCATION (decl) != input_location)
4105         {
4106           if (!check_abi_tag_redeclaration (decl,
4107                                             lookup_attribute ("abi_tag",
4108                                                               attributes),
4109                                             args))
4110             goto fail;
4111         }
4112     }
4113   else
4114     {
4115       if (!VAR_OR_FUNCTION_DECL_P (*node))
4116         {
4117           error ("%qE attribute applied to non-function, non-variable %qD",
4118                  name, *node);
4119           goto fail;
4120         }
4121       else if (DECL_LANGUAGE (*node) == lang_c)
4122         {
4123           error ("%qE attribute applied to extern \"C\" declaration %qD",
4124                  name, *node);
4125           goto fail;
4126         }
4127     }
4128
4129   return NULL_TREE;
4130
4131  fail:
4132   *no_add_attrs = true;
4133   return NULL_TREE;
4134 }
4135
4136 /* Return a new PTRMEM_CST of the indicated TYPE.  The MEMBER is the
4137    thing pointed to by the constant.  */
4138
4139 tree
4140 make_ptrmem_cst (tree type, tree member)
4141 {
4142   tree ptrmem_cst = make_node (PTRMEM_CST);
4143   TREE_TYPE (ptrmem_cst) = type;
4144   PTRMEM_CST_MEMBER (ptrmem_cst) = member;
4145   return ptrmem_cst;
4146 }
4147
4148 /* Build a variant of TYPE that has the indicated ATTRIBUTES.  May
4149    return an existing type if an appropriate type already exists.  */
4150
4151 tree
4152 cp_build_type_attribute_variant (tree type, tree attributes)
4153 {
4154   tree new_type;
4155
4156   new_type = build_type_attribute_variant (type, attributes);
4157   if (TREE_CODE (new_type) == FUNCTION_TYPE
4158       || TREE_CODE (new_type) == METHOD_TYPE)
4159     {
4160       new_type = build_exception_variant (new_type,
4161                                           TYPE_RAISES_EXCEPTIONS (type));
4162       new_type = build_ref_qualified_type (new_type,
4163                                            type_memfn_rqual (type));
4164     }
4165
4166   /* Making a new main variant of a class type is broken.  */
4167   gcc_assert (!CLASS_TYPE_P (type) || new_type == type);
4168
4169   return new_type;
4170 }
4171
4172 /* Return TRUE if TYPE1 and TYPE2 are identical for type hashing purposes.
4173    Called only after doing all language independent checks.  */
4174
4175 bool
4176 cxx_type_hash_eq (const_tree typea, const_tree typeb)
4177 {
4178   gcc_assert (TREE_CODE (typea) == FUNCTION_TYPE
4179               || TREE_CODE (typea) == METHOD_TYPE);
4180
4181   if (type_memfn_rqual (typea) != type_memfn_rqual (typeb))
4182     return false;
4183   return comp_except_specs (TYPE_RAISES_EXCEPTIONS (typea),
4184                             TYPE_RAISES_EXCEPTIONS (typeb), ce_exact);
4185 }
4186
4187 /* Apply FUNC to all language-specific sub-trees of TP in a pre-order
4188    traversal.  Called from walk_tree.  */
4189
4190 tree
4191 cp_walk_subtrees (tree *tp, int *walk_subtrees_p, walk_tree_fn func,
4192                   void *data, hash_set<tree> *pset)
4193 {
4194   enum tree_code code = TREE_CODE (*tp);
4195   tree result;
4196
4197 #define WALK_SUBTREE(NODE)                              \
4198   do                                                    \
4199     {                                                   \
4200       result = cp_walk_tree (&(NODE), func, data, pset);        \
4201       if (result) goto out;                             \
4202     }                                                   \
4203   while (0)
4204
4205   /* Not one of the easy cases.  We must explicitly go through the
4206      children.  */
4207   result = NULL_TREE;
4208   switch (code)
4209     {
4210     case DEFAULT_ARG:
4211     case TEMPLATE_TEMPLATE_PARM:
4212     case BOUND_TEMPLATE_TEMPLATE_PARM:
4213     case UNBOUND_CLASS_TEMPLATE:
4214     case TEMPLATE_PARM_INDEX:
4215     case TEMPLATE_TYPE_PARM:
4216     case TYPENAME_TYPE:
4217     case TYPEOF_TYPE:
4218     case UNDERLYING_TYPE:
4219       /* None of these have subtrees other than those already walked
4220          above.  */
4221       *walk_subtrees_p = 0;
4222       break;
4223
4224     case BASELINK:
4225       WALK_SUBTREE (BASELINK_FUNCTIONS (*tp));
4226       *walk_subtrees_p = 0;
4227       break;
4228
4229     case PTRMEM_CST:
4230       WALK_SUBTREE (TREE_TYPE (*tp));
4231       *walk_subtrees_p = 0;
4232       break;
4233
4234     case TREE_LIST:
4235       WALK_SUBTREE (TREE_PURPOSE (*tp));
4236       break;
4237
4238     case OVERLOAD:
4239       WALK_SUBTREE (OVL_FUNCTION (*tp));
4240       WALK_SUBTREE (OVL_CHAIN (*tp));
4241       *walk_subtrees_p = 0;
4242       break;
4243
4244     case USING_DECL:
4245       WALK_SUBTREE (DECL_NAME (*tp));
4246       WALK_SUBTREE (USING_DECL_SCOPE (*tp));
4247       WALK_SUBTREE (USING_DECL_DECLS (*tp));
4248       *walk_subtrees_p = 0;
4249       break;
4250
4251     case RECORD_TYPE:
4252       if (TYPE_PTRMEMFUNC_P (*tp))
4253         WALK_SUBTREE (TYPE_PTRMEMFUNC_FN_TYPE_RAW (*tp));
4254       break;
4255
4256     case TYPE_ARGUMENT_PACK:
4257     case NONTYPE_ARGUMENT_PACK:
4258       {
4259         tree args = ARGUMENT_PACK_ARGS (*tp);
4260         int i, len = TREE_VEC_LENGTH (args);
4261         for (i = 0; i < len; i++)
4262           WALK_SUBTREE (TREE_VEC_ELT (args, i));
4263       }
4264       break;
4265
4266     case TYPE_PACK_EXPANSION:
4267       WALK_SUBTREE (TREE_TYPE (*tp));
4268       WALK_SUBTREE (PACK_EXPANSION_EXTRA_ARGS (*tp));
4269       *walk_subtrees_p = 0;
4270       break;
4271
4272     case EXPR_PACK_EXPANSION:
4273       WALK_SUBTREE (TREE_OPERAND (*tp, 0));
4274       WALK_SUBTREE (PACK_EXPANSION_EXTRA_ARGS (*tp));
4275       *walk_subtrees_p = 0;
4276       break;
4277
4278     case CAST_EXPR:
4279     case REINTERPRET_CAST_EXPR:
4280     case STATIC_CAST_EXPR:
4281     case CONST_CAST_EXPR:
4282     case DYNAMIC_CAST_EXPR:
4283     case IMPLICIT_CONV_EXPR:
4284       if (TREE_TYPE (*tp))
4285         WALK_SUBTREE (TREE_TYPE (*tp));
4286
4287       {
4288         int i;
4289         for (i = 0; i < TREE_CODE_LENGTH (TREE_CODE (*tp)); ++i)
4290           WALK_SUBTREE (TREE_OPERAND (*tp, i));
4291       }
4292       *walk_subtrees_p = 0;
4293       break;
4294
4295     case TRAIT_EXPR:
4296       WALK_SUBTREE (TRAIT_EXPR_TYPE1 (*tp));
4297       WALK_SUBTREE (TRAIT_EXPR_TYPE2 (*tp));
4298       *walk_subtrees_p = 0;
4299       break;
4300
4301     case DECLTYPE_TYPE:
4302       WALK_SUBTREE (DECLTYPE_TYPE_EXPR (*tp));
4303       *walk_subtrees_p = 0;
4304       break;
4305
4306     case REQUIRES_EXPR:
4307       // Only recurse through the nested expression. Do not
4308       // walk the parameter list. Doing so causes false
4309       // positives in the pack expansion checker since the
4310       // requires parameters are introduced as pack expansions.
4311       WALK_SUBTREE (TREE_OPERAND (*tp, 1));
4312       *walk_subtrees_p = 0;
4313       break;
4314
4315     case DECL_EXPR:
4316       /* User variables should be mentioned in BIND_EXPR_VARS
4317          and their initializers and sizes walked when walking
4318          the containing BIND_EXPR.  Compiler temporaries are
4319          handled here.  */
4320       if (VAR_P (TREE_OPERAND (*tp, 0))
4321           && DECL_ARTIFICIAL (TREE_OPERAND (*tp, 0))
4322           && !TREE_STATIC (TREE_OPERAND (*tp, 0)))
4323         {
4324           tree decl = TREE_OPERAND (*tp, 0);
4325           WALK_SUBTREE (DECL_INITIAL (decl));
4326           WALK_SUBTREE (DECL_SIZE (decl));
4327           WALK_SUBTREE (DECL_SIZE_UNIT (decl));
4328         }
4329       break;
4330
4331     default:
4332       return NULL_TREE;
4333     }
4334
4335   /* We didn't find what we were looking for.  */
4336  out:
4337   return result;
4338
4339 #undef WALK_SUBTREE
4340 }
4341
4342 /* Like save_expr, but for C++.  */
4343
4344 tree
4345 cp_save_expr (tree expr)
4346 {
4347   /* There is no reason to create a SAVE_EXPR within a template; if
4348      needed, we can create the SAVE_EXPR when instantiating the
4349      template.  Furthermore, the middle-end cannot handle C++-specific
4350      tree codes.  */
4351   if (processing_template_decl)
4352     return expr;
4353   return save_expr (expr);
4354 }
4355
4356 /* Initialize tree.c.  */
4357
4358 void
4359 init_tree (void)
4360 {
4361   list_hash_table = hash_table<list_hasher>::create_ggc (61);
4362   register_scoped_attributes (std_attribute_table, NULL);
4363 }
4364
4365 /* Returns the kind of special function that DECL (a FUNCTION_DECL)
4366    is.  Note that sfk_none is zero, so this function can be used as a
4367    predicate to test whether or not DECL is a special function.  */
4368
4369 special_function_kind
4370 special_function_p (const_tree decl)
4371 {
4372   /* Rather than doing all this stuff with magic names, we should
4373      probably have a field of type `special_function_kind' in
4374      DECL_LANG_SPECIFIC.  */
4375   if (DECL_INHERITED_CTOR (decl))
4376     return sfk_inheriting_constructor;
4377   if (DECL_COPY_CONSTRUCTOR_P (decl))
4378     return sfk_copy_constructor;
4379   if (DECL_MOVE_CONSTRUCTOR_P (decl))
4380     return sfk_move_constructor;
4381   if (DECL_CONSTRUCTOR_P (decl))
4382     return sfk_constructor;
4383   if (DECL_OVERLOADED_OPERATOR_P (decl) == NOP_EXPR)
4384     {
4385       if (copy_fn_p (decl))
4386         return sfk_copy_assignment;
4387       if (move_fn_p (decl))
4388         return sfk_move_assignment;
4389     }
4390   if (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (decl))
4391     return sfk_destructor;
4392   if (DECL_COMPLETE_DESTRUCTOR_P (decl))
4393     return sfk_complete_destructor;
4394   if (DECL_BASE_DESTRUCTOR_P (decl))
4395     return sfk_base_destructor;
4396   if (DECL_DELETING_DESTRUCTOR_P (decl))
4397     return sfk_deleting_destructor;
4398   if (DECL_CONV_FN_P (decl))
4399     return sfk_conversion;
4400   if (deduction_guide_p (decl))
4401     return sfk_deduction_guide;
4402
4403   return sfk_none;
4404 }
4405
4406 /* Returns nonzero if TYPE is a character type, including wchar_t.  */
4407
4408 int
4409 char_type_p (tree type)
4410 {
4411   return (same_type_p (type, char_type_node)
4412           || same_type_p (type, unsigned_char_type_node)
4413           || same_type_p (type, signed_char_type_node)
4414           || same_type_p (type, char16_type_node)
4415           || same_type_p (type, char32_type_node)
4416           || same_type_p (type, wchar_type_node));
4417 }
4418
4419 /* Returns the kind of linkage associated with the indicated DECL.  Th
4420    value returned is as specified by the language standard; it is
4421    independent of implementation details regarding template
4422    instantiation, etc.  For example, it is possible that a declaration
4423    to which this function assigns external linkage would not show up
4424    as a global symbol when you run `nm' on the resulting object file.  */
4425
4426 linkage_kind
4427 decl_linkage (tree decl)
4428 {
4429   /* This function doesn't attempt to calculate the linkage from first
4430      principles as given in [basic.link].  Instead, it makes use of
4431      the fact that we have already set TREE_PUBLIC appropriately, and
4432      then handles a few special cases.  Ideally, we would calculate
4433      linkage first, and then transform that into a concrete
4434      implementation.  */
4435
4436   /* Things that don't have names have no linkage.  */
4437   if (!DECL_NAME (decl))
4438     return lk_none;
4439
4440   /* Fields have no linkage.  */
4441   if (TREE_CODE (decl) == FIELD_DECL)
4442     return lk_none;
4443
4444   /* Things that are TREE_PUBLIC have external linkage.  */
4445   if (TREE_PUBLIC (decl))
4446     return lk_external;
4447
4448   /* maybe_thunk_body clears TREE_PUBLIC on the maybe-in-charge 'tor variants,
4449      check one of the "clones" for the real linkage.  */
4450   if ((DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (decl)
4451        || DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (decl))
4452       && DECL_CHAIN (decl)
4453       && DECL_CLONED_FUNCTION (DECL_CHAIN (decl)))
4454     return decl_linkage (DECL_CHAIN (decl));
4455
4456   if (TREE_CODE (decl) == NAMESPACE_DECL)
4457     return lk_external;
4458
4459   /* Linkage of a CONST_DECL depends on the linkage of the enumeration
4460      type.  */
4461   if (TREE_CODE (decl) == CONST_DECL)
4462     return decl_linkage (TYPE_NAME (DECL_CONTEXT (decl)));
4463
4464   /* Things in local scope do not have linkage, if they don't have
4465      TREE_PUBLIC set.  */
4466   if (decl_function_context (decl))
4467     return lk_none;
4468
4469   /* Members of the anonymous namespace also have TREE_PUBLIC unset, but
4470      are considered to have external linkage for language purposes, as do
4471      template instantiations on targets without weak symbols.  DECLs really
4472      meant to have internal linkage have DECL_THIS_STATIC set.  */
4473   if (TREE_CODE (decl) == TYPE_DECL)
4474     return lk_external;
4475   if (VAR_OR_FUNCTION_DECL_P (decl))
4476     {
4477       if (!DECL_THIS_STATIC (decl))
4478         return lk_external;
4479
4480       /* Static data members and static member functions from classes
4481          in anonymous namespace also don't have TREE_PUBLIC set.  */
4482       if (DECL_CLASS_CONTEXT (decl))
4483         return lk_external;
4484     }
4485
4486   /* Everything else has internal linkage.  */
4487   return lk_internal;
4488 }
4489
4490 /* Returns the storage duration of the object or reference associated with
4491    the indicated DECL, which should be a VAR_DECL or PARM_DECL.  */
4492
4493 duration_kind
4494 decl_storage_duration (tree decl)
4495 {
4496   if (TREE_CODE (decl) == PARM_DECL)
4497     return dk_auto;
4498   if (TREE_CODE (decl) == FUNCTION_DECL)
4499     return dk_static;
4500   gcc_assert (VAR_P (decl));
4501   if (!TREE_STATIC (decl)
4502       && !DECL_EXTERNAL (decl))
4503     return dk_auto;
4504   if (CP_DECL_THREAD_LOCAL_P (decl))
4505     return dk_thread;
4506   return dk_static;
4507 }
4508 \f
4509 /* EXP is an expression that we want to pre-evaluate.  Returns (in
4510    *INITP) an expression that will perform the pre-evaluation.  The
4511    value returned by this function is a side-effect free expression
4512    equivalent to the pre-evaluated expression.  Callers must ensure
4513    that *INITP is evaluated before EXP.  */
4514
4515 tree
4516 stabilize_expr (tree exp, tree* initp)
4517 {
4518   tree init_expr;
4519
4520   if (!TREE_SIDE_EFFECTS (exp))
4521     init_expr = NULL_TREE;
4522   else if (VOID_TYPE_P (TREE_TYPE (exp)))
4523     {
4524       init_expr = exp;
4525       exp = void_node;
4526     }
4527   /* There are no expressions with REFERENCE_TYPE, but there can be call
4528      arguments with such a type; just treat it as a pointer.  */
4529   else if (TREE_CODE (TREE_TYPE (exp)) == REFERENCE_TYPE
4530            || SCALAR_TYPE_P (TREE_TYPE (exp))
4531            || !glvalue_p (exp))
4532     {
4533       init_expr = get_target_expr (exp);
4534       exp = TARGET_EXPR_SLOT (init_expr);
4535       if (CLASS_TYPE_P (TREE_TYPE (exp)))
4536         exp = move (exp);
4537       else
4538         exp = rvalue (exp);
4539     }
4540   else
4541     {
4542       bool xval = !lvalue_p (exp);
4543       exp = cp_build_addr_expr (exp, tf_warning_or_error);
4544       init_expr = get_target_expr (exp);
4545       exp = TARGET_EXPR_SLOT (init_expr);
4546       exp = cp_build_indirect_ref (exp, RO_NULL, tf_warning_or_error);
4547       if (xval)
4548         exp = move (exp);
4549     }
4550   *initp = init_expr;
4551
4552   gcc_assert (!TREE_SIDE_EFFECTS (exp));
4553   return exp;
4554 }
4555
4556 /* Add NEW_EXPR, an expression whose value we don't care about, after the
4557    similar expression ORIG.  */
4558
4559 tree
4560 add_stmt_to_compound (tree orig, tree new_expr)
4561 {
4562   if (!new_expr || !TREE_SIDE_EFFECTS (new_expr))
4563     return orig;
4564   if (!orig || !TREE_SIDE_EFFECTS (orig))
4565     return new_expr;
4566   return build2 (COMPOUND_EXPR, void_type_node, orig, new_expr);
4567 }
4568
4569 /* Like stabilize_expr, but for a call whose arguments we want to
4570    pre-evaluate.  CALL is modified in place to use the pre-evaluated
4571    arguments, while, upon return, *INITP contains an expression to
4572    compute the arguments.  */
4573
4574 void
4575 stabilize_call (tree call, tree *initp)
4576 {
4577   tree inits = NULL_TREE;
4578   int i;
4579   int nargs = call_expr_nargs (call);
4580
4581   if (call == error_mark_node || processing_template_decl)
4582     {
4583       *initp = NULL_TREE;
4584       return;
4585     }
4586
4587   gcc_assert (TREE_CODE (call) == CALL_EXPR);
4588
4589   for (i = 0; i < nargs; i++)
4590     {
4591       tree init;
4592       CALL_EXPR_ARG (call, i) =
4593         stabilize_expr (CALL_EXPR_ARG (call, i), &init);
4594       inits = add_stmt_to_compound (inits, init);
4595     }
4596
4597   *initp = inits;
4598 }
4599
4600 /* Like stabilize_expr, but for an AGGR_INIT_EXPR whose arguments we want
4601    to pre-evaluate.  CALL is modified in place to use the pre-evaluated
4602    arguments, while, upon return, *INITP contains an expression to
4603    compute the arguments.  */
4604
4605 static void
4606 stabilize_aggr_init (tree call, tree *initp)
4607 {
4608   tree inits = NULL_TREE;
4609   int i;
4610   int nargs = aggr_init_expr_nargs (call);
4611
4612   if (call == error_mark_node)
4613     return;
4614
4615   gcc_assert (TREE_CODE (call) == AGGR_INIT_EXPR);
4616
4617   for (i = 0; i < nargs; i++)
4618     {
4619       tree init;
4620       AGGR_INIT_EXPR_ARG (call, i) =
4621         stabilize_expr (AGGR_INIT_EXPR_ARG (call, i), &init);
4622       inits = add_stmt_to_compound (inits, init);
4623     }
4624
4625   *initp = inits;
4626 }
4627
4628 /* Like stabilize_expr, but for an initialization.
4629
4630    If the initialization is for an object of class type, this function
4631    takes care not to introduce additional temporaries.
4632
4633    Returns TRUE iff the expression was successfully pre-evaluated,
4634    i.e., if INIT is now side-effect free, except for, possibly, a
4635    single call to a constructor.  */
4636
4637 bool
4638 stabilize_init (tree init, tree *initp)
4639 {
4640   tree t = init;
4641
4642   *initp = NULL_TREE;
4643
4644   if (t == error_mark_node || processing_template_decl)
4645     return true;
4646
4647   if (TREE_CODE (t) == INIT_EXPR)
4648     t = TREE_OPERAND (t, 1);
4649   if (TREE_CODE (t) == TARGET_EXPR)
4650     t = TARGET_EXPR_INITIAL (t);
4651
4652   /* If the RHS can be stabilized without breaking copy elision, stabilize
4653      it.  We specifically don't stabilize class prvalues here because that
4654      would mean an extra copy, but they might be stabilized below.  */
4655   if (TREE_CODE (init) == INIT_EXPR
4656       && TREE_CODE (t) != CONSTRUCTOR
4657       && TREE_CODE (t) != AGGR_INIT_EXPR
4658       && (SCALAR_TYPE_P (TREE_TYPE (t))
4659           || glvalue_p (t)))
4660     {
4661       TREE_OPERAND (init, 1) = stabilize_expr (t, initp);
4662       return true;
4663     }
4664
4665   if (TREE_CODE (t) == COMPOUND_EXPR
4666       && TREE_CODE (init) == INIT_EXPR)
4667     {
4668       tree last = expr_last (t);
4669       /* Handle stabilizing the EMPTY_CLASS_EXPR pattern.  */
4670       if (!TREE_SIDE_EFFECTS (last))
4671         {
4672           *initp = t;
4673           TREE_OPERAND (init, 1) = last;
4674           return true;
4675         }
4676     }
4677
4678   if (TREE_CODE (t) == CONSTRUCTOR)
4679     {
4680       /* Aggregate initialization: stabilize each of the field
4681          initializers.  */
4682       unsigned i;
4683       constructor_elt *ce;
4684       bool good = true;
4685       vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t);
4686       for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
4687         {
4688           tree type = TREE_TYPE (ce->value);
4689           tree subinit;
4690           if (TREE_CODE (type) == REFERENCE_TYPE
4691               || SCALAR_TYPE_P (type))
4692             ce->value = stabilize_expr (ce->value, &subinit);
4693           else if (!stabilize_init (ce->value, &subinit))
4694             good = false;
4695           *initp = add_stmt_to_compound (*initp, subinit);
4696         }
4697       return good;
4698     }
4699
4700   if (TREE_CODE (t) == CALL_EXPR)
4701     {
4702       stabilize_call (t, initp);
4703       return true;
4704     }
4705
4706   if (TREE_CODE (t) == AGGR_INIT_EXPR)
4707     {
4708       stabilize_aggr_init (t, initp);
4709       return true;
4710     }
4711
4712   /* The initialization is being performed via a bitwise copy -- and
4713      the item copied may have side effects.  */
4714   return !TREE_SIDE_EFFECTS (init);
4715 }
4716
4717 /* Returns true if a cast to TYPE may appear in an integral constant
4718    expression.  */
4719
4720 bool
4721 cast_valid_in_integral_constant_expression_p (tree type)
4722 {
4723   return (INTEGRAL_OR_ENUMERATION_TYPE_P (type)
4724           || cxx_dialect >= cxx11
4725           || dependent_type_p (type)
4726           || type == error_mark_node);
4727 }
4728
4729 /* Return true if we need to fix linkage information of DECL.  */
4730
4731 static bool
4732 cp_fix_function_decl_p (tree decl)
4733 {
4734   /* Skip if DECL is not externally visible.  */
4735   if (!TREE_PUBLIC (decl))
4736     return false;
4737
4738   /* We need to fix DECL if it a appears to be exported but with no
4739      function body.  Thunks do not have CFGs and we may need to
4740      handle them specially later.   */
4741   if (!gimple_has_body_p (decl)
4742       && !DECL_THUNK_P (decl)
4743       && !DECL_EXTERNAL (decl))
4744     {
4745       struct cgraph_node *node = cgraph_node::get (decl);
4746
4747       /* Don't fix same_body aliases.  Although they don't have their own
4748          CFG, they share it with what they alias to.  */
4749       if (!node || !node->alias
4750           || !vec_safe_length (node->ref_list.references))
4751         return true;
4752     }
4753
4754   return false;
4755 }
4756
4757 /* Clean the C++ specific parts of the tree T. */
4758
4759 void
4760 cp_free_lang_data (tree t)
4761 {
4762   if (TREE_CODE (t) == METHOD_TYPE
4763       || TREE_CODE (t) == FUNCTION_TYPE)
4764     {
4765       /* Default args are not interesting anymore.  */
4766       tree argtypes = TYPE_ARG_TYPES (t);
4767       while (argtypes)
4768         {
4769           TREE_PURPOSE (argtypes) = 0;
4770           argtypes = TREE_CHAIN (argtypes);
4771         }
4772     }
4773   else if (TREE_CODE (t) == FUNCTION_DECL
4774            && cp_fix_function_decl_p (t))
4775     {
4776       /* If T is used in this translation unit at all,  the definition
4777          must exist somewhere else since we have decided to not emit it
4778          in this TU.  So make it an external reference.  */
4779       DECL_EXTERNAL (t) = 1;
4780       TREE_STATIC (t) = 0;
4781     }
4782   if (TREE_CODE (t) == NAMESPACE_DECL)
4783     {
4784       /* The list of users of a namespace isn't useful for the middle-end
4785          or debug generators.  */
4786       DECL_NAMESPACE_USERS (t) = NULL_TREE;
4787       /* Neither do we need the leftover chaining of namespaces
4788          from the binding level.  */
4789       DECL_CHAIN (t) = NULL_TREE;
4790     }
4791 }
4792
4793 /* Stub for c-common.  Please keep in sync with c-decl.c.
4794    FIXME: If address space support is target specific, then this
4795    should be a C target hook.  But currently this is not possible,
4796    because this function is called via REGISTER_TARGET_PRAGMAS.  */
4797 void
4798 c_register_addr_space (const char * /*word*/, addr_space_t /*as*/)
4799 {
4800 }
4801
4802 /* Return the number of operands in T that we care about for things like
4803    mangling.  */
4804
4805 int
4806 cp_tree_operand_length (const_tree t)
4807 {
4808   enum tree_code code = TREE_CODE (t);
4809
4810   if (TREE_CODE_CLASS (code) == tcc_vl_exp)
4811     return VL_EXP_OPERAND_LENGTH (t);
4812
4813   return cp_tree_code_length (code);
4814 }
4815
4816 /* Like cp_tree_operand_length, but takes a tree_code CODE.  */
4817
4818 int
4819 cp_tree_code_length (enum tree_code code)
4820 {
4821   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
4822
4823   switch (code)
4824     {
4825     case PREINCREMENT_EXPR:
4826     case PREDECREMENT_EXPR:
4827     case POSTINCREMENT_EXPR:
4828     case POSTDECREMENT_EXPR:
4829       return 1;
4830
4831     case ARRAY_REF:
4832       return 2;
4833
4834     case EXPR_PACK_EXPANSION:
4835       return 1;
4836
4837     default:
4838       return TREE_CODE_LENGTH (code);
4839     }
4840 }
4841
4842 /* Implement -Wzero_as_null_pointer_constant.  Return true if the
4843    conditions for the warning hold, false otherwise.  */
4844 bool
4845 maybe_warn_zero_as_null_pointer_constant (tree expr, location_t loc)
4846 {
4847   if (c_inhibit_evaluation_warnings == 0
4848       && !NULLPTR_TYPE_P (TREE_TYPE (expr)))
4849     {
4850       warning_at (loc, OPT_Wzero_as_null_pointer_constant,
4851                   "zero as null pointer constant");
4852       return true;
4853     }
4854   return false;
4855 }
4856 \f
4857 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4858 /* Complain that some language-specific thing hanging off a tree
4859    node has been accessed improperly.  */
4860
4861 void
4862 lang_check_failed (const char* file, int line, const char* function)
4863 {
4864   internal_error ("lang_* check: failed in %s, at %s:%d",
4865                   function, trim_filename (file), line);
4866 }
4867 #endif /* ENABLE_TREE_CHECKING */
4868
4869 #include "gt-cp-tree.h"