gcc/cp/method.c

   1 /* Handle the hair of processing (but not expanding) inline functions.
   2    Also manage function and variable name overloading.
   3    Copyright (C) 1987-2017 Free Software Foundation, Inc.
   4    Contributed by Michael Tiemann (tiemann@cygnus.com)
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* Handle method declarations.  */
  24 #include "config.h"
  25 #include "system.h"
  26 #include "coretypes.h"
  27 #include "target.h"
  28 #include "cp-tree.h"
  29 #include "stringpool.h"
  30 #include "cgraph.h"
  31 #include "varasm.h"
  32 #include "toplev.h"
  33 #include "common/common-target.h"
  34
  35 /* Various flags to control the mangling process.  */
  36
  37 enum mangling_flags
  38 {
  39   /* No flags.  */
  40   mf_none = 0,
  41   /* The thing we are presently mangling is part of a template type,
  42      rather than a fully instantiated type.  Therefore, we may see
  43      complex expressions where we would normally expect to see a
  44      simple integer constant.  */
  45   mf_maybe_uninstantiated = 1,
  46   /* When mangling a numeric value, use the form `_XX_' (instead of
  47      just `XX') if the value has more than one digit.  */
  48   mf_use_underscores_around_value = 2
  49 };
  50
  51 static void do_build_copy_assign (tree);
  52 static void do_build_copy_constructor (tree);
  53 static tree make_alias_for_thunk (tree);
  54
  55 /* Called once to initialize method.c.  */
  56
  57 void
  58 init_method (void)
  59 {
  60   init_mangle ();
  61 }
  62 \f
  63 /* Return a this or result adjusting thunk to FUNCTION.  THIS_ADJUSTING
  64    indicates whether it is a this or result adjusting thunk.
  65    FIXED_OFFSET and VIRTUAL_OFFSET indicate how to do the adjustment
  66    (see thunk_adjust).  VIRTUAL_OFFSET can be NULL, but FIXED_OFFSET
  67    never is.  VIRTUAL_OFFSET is the /index/ into the vtable for this
  68    adjusting thunks, we scale it to a byte offset. For covariant
  69    thunks VIRTUAL_OFFSET is the virtual binfo.  You must post process
  70    the returned thunk with finish_thunk.  */
  71
  72 tree
  73 make_thunk (tree function, bool this_adjusting,
  74             tree fixed_offset, tree virtual_offset)
  75 {
  76   HOST_WIDE_INT d;
  77   tree thunk;
  78
  79   gcc_assert (TREE_CODE (function) == FUNCTION_DECL);
  80   /* We can have this thunks to covariant thunks, but not vice versa.  */
  81   gcc_assert (!DECL_THIS_THUNK_P (function));
  82   gcc_assert (!DECL_RESULT_THUNK_P (function) || this_adjusting);
  83
  84   /* Scale the VIRTUAL_OFFSET to be in terms of bytes.  */
  85   if (this_adjusting && virtual_offset)
  86     virtual_offset
  87       = size_binop (MULT_EXPR,
  88                     virtual_offset,
  89                     convert (ssizetype,
  90                              TYPE_SIZE_UNIT (vtable_entry_type)));
  91
  92   d = tree_to_shwi (fixed_offset);
  93
  94   /* See if we already have the thunk in question.  For this_adjusting
  95      thunks VIRTUAL_OFFSET will be an INTEGER_CST, for covariant thunks it
  96      will be a BINFO.  */
  97   for (thunk = DECL_THUNKS (function); thunk; thunk = DECL_CHAIN (thunk))
  98     if (DECL_THIS_THUNK_P (thunk) == this_adjusting
  99         && THUNK_FIXED_OFFSET (thunk) == d
 100         && !virtual_offset == !THUNK_VIRTUAL_OFFSET (thunk)
 101         && (!virtual_offset
 102             || (this_adjusting
 103                 ? tree_int_cst_equal (THUNK_VIRTUAL_OFFSET (thunk),
 104                                       virtual_offset)
 105                 : THUNK_VIRTUAL_OFFSET (thunk) == virtual_offset)))
 106       return thunk;
 107
 108   /* All thunks must be created before FUNCTION is actually emitted;
 109      the ABI requires that all thunks be emitted together with the
 110      function to which they transfer control.  */
 111   gcc_assert (!TREE_ASM_WRITTEN (function));
 112   /* Likewise, we can only be adding thunks to a function declared in
 113      the class currently being laid out.  */
 114   gcc_assert (TYPE_SIZE (DECL_CONTEXT (function))
 115               && TYPE_BEING_DEFINED (DECL_CONTEXT (function)));
 116
 117   thunk = build_decl (DECL_SOURCE_LOCATION (function),
 118                       FUNCTION_DECL, NULL_TREE, TREE_TYPE (function));
 119   DECL_LANG_SPECIFIC (thunk) = DECL_LANG_SPECIFIC (function);
 120   cxx_dup_lang_specific_decl (thunk);
 121   DECL_VIRTUAL_P (thunk) = true;
 122   SET_DECL_THUNKS (thunk, NULL_TREE);
 123
 124   DECL_CONTEXT (thunk) = DECL_CONTEXT (function);
 125   TREE_READONLY (thunk) = TREE_READONLY (function);
 126   TREE_THIS_VOLATILE (thunk) = TREE_THIS_VOLATILE (function);
 127   TREE_PUBLIC (thunk) = TREE_PUBLIC (function);
 128   SET_DECL_THUNK_P (thunk, this_adjusting);
 129   THUNK_TARGET (thunk) = function;
 130   THUNK_FIXED_OFFSET (thunk) = d;
 131   THUNK_VIRTUAL_OFFSET (thunk) = virtual_offset;
 132   THUNK_ALIAS (thunk) = NULL_TREE;
 133
 134   DECL_INTERFACE_KNOWN (thunk) = 1;
 135   DECL_NOT_REALLY_EXTERN (thunk) = 1;
 136   DECL_COMDAT (thunk) = DECL_COMDAT (function);
 137   DECL_SAVED_FUNCTION_DATA (thunk) = NULL;
 138   /* The thunk itself is not a constructor or destructor, even if
 139      the thing it is thunking to is.  */
 140   DECL_DESTRUCTOR_P (thunk) = 0;
 141   DECL_CONSTRUCTOR_P (thunk) = 0;
 142   DECL_EXTERNAL (thunk) = 1;
 143   DECL_ARTIFICIAL (thunk) = 1;
 144   /* The THUNK is not a pending inline, even if the FUNCTION is.  */
 145   DECL_PENDING_INLINE_P (thunk) = 0;
 146   DECL_DECLARED_INLINE_P (thunk) = 0;
 147   /* Nor is it a template instantiation.  */
 148   DECL_USE_TEMPLATE (thunk) = 0;
 149   DECL_TEMPLATE_INFO (thunk) = NULL;
 150
 151   /* Add it to the list of thunks associated with FUNCTION.  */
 152   DECL_CHAIN (thunk) = DECL_THUNKS (function);
 153   SET_DECL_THUNKS (function, thunk);
 154
 155   return thunk;
 156 }
 157
 158 /* Finish THUNK, a thunk decl.  */
 159
 160 void
 161 finish_thunk (tree thunk)
 162 {
 163   tree function, name;
 164   tree fixed_offset = ssize_int (THUNK_FIXED_OFFSET (thunk));
 165   tree virtual_offset = THUNK_VIRTUAL_OFFSET (thunk);
 166
 167   gcc_assert (!DECL_NAME (thunk) && DECL_THUNK_P (thunk));
 168   if (virtual_offset && DECL_RESULT_THUNK_P (thunk))
 169     virtual_offset = BINFO_VPTR_FIELD (virtual_offset);
 170   function = THUNK_TARGET (thunk);
 171   name = mangle_thunk (function, DECL_THIS_THUNK_P (thunk),
 172                        fixed_offset, virtual_offset, thunk);
 173
 174   /* We can end up with declarations of (logically) different
 175      covariant thunks, that do identical adjustments.  The two thunks
 176      will be adjusting between within different hierarchies, which
 177      happen to have the same layout.  We must nullify one of them to
 178      refer to the other.  */
 179   if (DECL_RESULT_THUNK_P (thunk))
 180     {
 181       tree cov_probe;
 182
 183       for (cov_probe = DECL_THUNKS (function);
 184            cov_probe; cov_probe = DECL_CHAIN (cov_probe))
 185         if (DECL_NAME (cov_probe) == name)
 186           {
 187             gcc_assert (!DECL_THUNKS (thunk));
 188             THUNK_ALIAS (thunk) = (THUNK_ALIAS (cov_probe)
 189                                    ? THUNK_ALIAS (cov_probe) : cov_probe);
 190             break;
 191           }
 192     }
 193
 194   DECL_NAME (thunk) = name;
 195   SET_DECL_ASSEMBLER_NAME (thunk, name);
 196 }
 197
 198 static GTY (()) int thunk_labelno;
 199
 200 /* Create a static alias to target.  */
 201
 202 tree
 203 make_alias_for (tree target, tree newid)
 204 {
 205   tree alias = build_decl (DECL_SOURCE_LOCATION (target),
 206                            TREE_CODE (target), newid, TREE_TYPE (target));
 207   DECL_LANG_SPECIFIC (alias) = DECL_LANG_SPECIFIC (target);
 208   cxx_dup_lang_specific_decl (alias);
 209   DECL_CONTEXT (alias) = NULL;
 210   TREE_READONLY (alias) = TREE_READONLY (target);
 211   TREE_THIS_VOLATILE (alias) = TREE_THIS_VOLATILE (target);
 212   TREE_PUBLIC (alias) = 0;
 213   DECL_INTERFACE_KNOWN (alias) = 1;
 214   if (DECL_LANG_SPECIFIC (alias))
 215     {
 216       DECL_NOT_REALLY_EXTERN (alias) = 1;
 217       DECL_USE_TEMPLATE (alias) = 0;
 218       DECL_TEMPLATE_INFO (alias) = NULL;
 219     }
 220   DECL_EXTERNAL (alias) = 0;
 221   DECL_ARTIFICIAL (alias) = 1;
 222   DECL_TEMPLATE_INSTANTIATED (alias) = 0;
 223   if (TREE_CODE (alias) == FUNCTION_DECL)
 224     {
 225       DECL_SAVED_FUNCTION_DATA (alias) = NULL;
 226       DECL_DESTRUCTOR_P (alias) = 0;
 227       DECL_CONSTRUCTOR_P (alias) = 0;
 228       DECL_PENDING_INLINE_P (alias) = 0;
 229       DECL_DECLARED_INLINE_P (alias) = 0;
 230       DECL_INITIAL (alias) = error_mark_node;
 231       DECL_ARGUMENTS (alias) = copy_list (DECL_ARGUMENTS (target));
 232     }
 233   else
 234     TREE_STATIC (alias) = 1;
 235   TREE_ADDRESSABLE (alias) = 1;
 236   TREE_USED (alias) = 1;
 237   SET_DECL_ASSEMBLER_NAME (alias, DECL_NAME (alias));
 238   return alias;
 239 }
 240
 241 static tree
 242 make_alias_for_thunk (tree function)
 243 {
 244   tree alias;
 245   char buf[256];
 246
 247   targetm.asm_out.generate_internal_label (buf, "LTHUNK", thunk_labelno);
 248   thunk_labelno++;
 249
 250   alias = make_alias_for (function, get_identifier (buf));
 251
 252   if (!flag_syntax_only)
 253     {
 254       struct cgraph_node *funcn, *aliasn;
 255       funcn = cgraph_node::get (function);
 256       gcc_checking_assert (funcn);
 257       aliasn = cgraph_node::create_same_body_alias (alias, function);
 258       DECL_ASSEMBLER_NAME (function);
 259       gcc_assert (aliasn != NULL);
 260     }
 261
 262   return alias;
 263 }
 264
 265 /* Emit the definition of a C++ multiple inheritance or covariant
 266    return vtable thunk.  If EMIT_P is nonzero, the thunk is emitted
 267    immediately.  */
 268
 269 void
 270 use_thunk (tree thunk_fndecl, bool emit_p)
 271 {
 272   tree a, t, function, alias;
 273   tree virtual_offset;
 274   HOST_WIDE_INT fixed_offset, virtual_value;
 275   bool this_adjusting = DECL_THIS_THUNK_P (thunk_fndecl);
 276   struct cgraph_node *funcn, *thunk_node;
 277
 278   /* We should have called finish_thunk to give it a name.  */
 279   gcc_assert (DECL_NAME (thunk_fndecl));
 280
 281   /* We should never be using an alias, always refer to the
 282      aliased thunk.  */
 283   gcc_assert (!THUNK_ALIAS (thunk_fndecl));
 284
 285   if (TREE_ASM_WRITTEN (thunk_fndecl))
 286     return;
 287
 288   function = THUNK_TARGET (thunk_fndecl);
 289   if (DECL_RESULT (thunk_fndecl))
 290     /* We already turned this thunk into an ordinary function.
 291        There's no need to process this thunk again.  */
 292     return;
 293
 294   if (DECL_THUNK_P (function))
 295     /* The target is itself a thunk, process it now.  */
 296     use_thunk (function, emit_p);
 297
 298   /* Thunks are always addressable; they only appear in vtables.  */
 299   TREE_ADDRESSABLE (thunk_fndecl) = 1;
 300
 301   /* Figure out what function is being thunked to.  It's referenced in
 302      this translation unit.  */
 303   TREE_ADDRESSABLE (function) = 1;
 304   mark_used (function);
 305   if (!emit_p)
 306     return;
 307
 308   if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function))
 309    alias = make_alias_for_thunk (function);
 310   else
 311    alias = function;
 312
 313   fixed_offset = THUNK_FIXED_OFFSET (thunk_fndecl);
 314   virtual_offset = THUNK_VIRTUAL_OFFSET (thunk_fndecl);
 315
 316   if (virtual_offset)
 317     {
 318       if (!this_adjusting)
 319         virtual_offset = BINFO_VPTR_FIELD (virtual_offset);
 320       virtual_value = tree_to_shwi (virtual_offset);
 321       gcc_assert (virtual_value);
 322     }
 323   else
 324     virtual_value = 0;
 325
 326   /* And, if we need to emit the thunk, it's used.  */
 327   mark_used (thunk_fndecl);
 328   /* This thunk is actually defined.  */
 329   DECL_EXTERNAL (thunk_fndecl) = 0;
 330   /* The linkage of the function may have changed.  FIXME in linkage
 331      rewrite.  */
 332   gcc_assert (DECL_INTERFACE_KNOWN (function));
 333   TREE_PUBLIC (thunk_fndecl) = TREE_PUBLIC (function);
 334   DECL_VISIBILITY (thunk_fndecl) = DECL_VISIBILITY (function);
 335   DECL_VISIBILITY_SPECIFIED (thunk_fndecl)
 336     = DECL_VISIBILITY_SPECIFIED (function);
 337   DECL_COMDAT (thunk_fndecl) = DECL_COMDAT (function);
 338   DECL_WEAK (thunk_fndecl) = DECL_WEAK (function);
 339
 340   if (flag_syntax_only)
 341     {
 342       TREE_ASM_WRITTEN (thunk_fndecl) = 1;
 343       return;
 344     }
 345
 346   push_to_top_level ();
 347
 348   if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function)
 349       && targetm_common.have_named_sections)
 350     {
 351       tree fn = function;
 352       struct symtab_node *symbol;
 353
 354       if ((symbol = symtab_node::get (function))
 355           && symbol->alias)
 356         {
 357           if (symbol->analyzed)
 358             fn = symtab_node::get (function)->ultimate_alias_target ()->decl;
 359           else
 360             fn = symtab_node::get (function)->alias_target;
 361         }
 362       resolve_unique_section (fn, 0, flag_function_sections);
 363
 364       if (DECL_SECTION_NAME (fn) != NULL && DECL_ONE_ONLY (fn))
 365         {
 366           resolve_unique_section (thunk_fndecl, 0, flag_function_sections);
 367
 368           /* Output the thunk into the same section as function.  */
 369           set_decl_section_name (thunk_fndecl, DECL_SECTION_NAME (fn));
 370           symtab_node::get (thunk_fndecl)->implicit_section
 371             = symtab_node::get (fn)->implicit_section;
 372         }
 373     }
 374
 375   /* Set up cloned argument trees for the thunk.  */
 376   t = NULL_TREE;
 377   for (a = DECL_ARGUMENTS (function); a; a = DECL_CHAIN (a))
 378     {
 379       tree x = copy_node (a);
 380       DECL_CHAIN (x) = t;
 381       DECL_CONTEXT (x) = thunk_fndecl;
 382       SET_DECL_RTL (x, NULL);
 383       DECL_HAS_VALUE_EXPR_P (x) = 0;
 384       TREE_ADDRESSABLE (x) = 0;
 385       t = x;
 386     }
 387   a = nreverse (t);
 388   DECL_ARGUMENTS (thunk_fndecl) = a;
 389   TREE_ASM_WRITTEN (thunk_fndecl) = 1;
 390   funcn = cgraph_node::get (function);
 391   gcc_checking_assert (funcn);
 392   thunk_node = funcn->create_thunk (thunk_fndecl, function,
 393                                     this_adjusting, fixed_offset, virtual_value,
 394                                     virtual_offset, alias);
 395   if (DECL_ONE_ONLY (function))
 396     thunk_node->add_to_same_comdat_group (funcn);
 397
 398   pop_from_top_level ();
 399 }
 400 \f
 401 /* Code for synthesizing methods which have default semantics defined.  */
 402
 403 /* True iff CTYPE has a trivial SFK.  */
 404
 405 static bool
 406 type_has_trivial_fn (tree ctype, special_function_kind sfk)
 407 {
 408   switch (sfk)
 409     {
 410     case sfk_constructor:
 411       return !TYPE_HAS_COMPLEX_DFLT (ctype);
 412     case sfk_copy_constructor:
 413       return !TYPE_HAS_COMPLEX_COPY_CTOR (ctype);
 414     case sfk_move_constructor:
 415       return !TYPE_HAS_COMPLEX_MOVE_CTOR (ctype);
 416     case sfk_copy_assignment:
 417       return !TYPE_HAS_COMPLEX_COPY_ASSIGN (ctype);
 418     case sfk_move_assignment:
 419       return !TYPE_HAS_COMPLEX_MOVE_ASSIGN (ctype);
 420     case sfk_destructor:
 421       return !TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype);
 422     case sfk_inheriting_constructor:
 423       return false;
 424     default:
 425       gcc_unreachable ();
 426     }
 427 }
 428
 429 /* Note that CTYPE has a non-trivial SFK even though we previously thought
 430    it was trivial.  */
 431
 432 static void
 433 type_set_nontrivial_flag (tree ctype, special_function_kind sfk)
 434 {
 435   switch (sfk)
 436     {
 437     case sfk_constructor:
 438       TYPE_HAS_COMPLEX_DFLT (ctype) = true;
 439       return;
 440     case sfk_copy_constructor:
 441       TYPE_HAS_COMPLEX_COPY_CTOR (ctype) = true;
 442       return;
 443     case sfk_move_constructor:
 444       TYPE_HAS_COMPLEX_MOVE_CTOR (ctype) = true;
 445       return;
 446     case sfk_copy_assignment:
 447       TYPE_HAS_COMPLEX_COPY_ASSIGN (ctype) = true;
 448       return;
 449     case sfk_move_assignment:
 450       TYPE_HAS_COMPLEX_MOVE_ASSIGN (ctype) = true;
 451       return;
 452     case sfk_destructor:
 453       TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype) = true;
 454       return;
 455     case sfk_inheriting_constructor:
 456     default:
 457       gcc_unreachable ();
 458     }
 459 }
 460
 461 /* True iff FN is a trivial defaulted member function ([cd]tor, op=).  */
 462
 463 bool
 464 trivial_fn_p (tree fn)
 465 {
 466   if (TREE_CODE (fn) == TEMPLATE_DECL)
 467     return false;
 468   if (!DECL_DEFAULTED_FN (fn))
 469     return false;
 470
 471   /* If fn is a clone, get the primary variant.  */
 472   if (tree prim = DECL_CLONED_FUNCTION (fn))
 473     fn = prim;
 474   return type_has_trivial_fn (DECL_CONTEXT (fn), special_function_p (fn));
 475 }
 476
 477 /* PARM is a PARM_DECL for a function which we want to forward to another
 478    function without changing its value category, a la std::forward.  */
 479
 480 tree
 481 forward_parm (tree parm)
 482 {
 483   tree exp = convert_from_reference (parm);
 484   tree type = TREE_TYPE (parm);
 485   if (DECL_PACK_P (parm))
 486     type = PACK_EXPANSION_PATTERN (type);
 487   if (TREE_CODE (type) != REFERENCE_TYPE)
 488     type = cp_build_reference_type (type, /*rval=*/true);
 489   exp = build_static_cast (type, exp, tf_warning_or_error);
 490   if (DECL_PACK_P (parm))
 491     exp = make_pack_expansion (exp);
 492   return exp;
 493 }
 494
 495 /* Strip all inheriting constructors, if any, to return the original
 496    constructor from a (possibly indirect) base class.  */
 497
 498 tree
 499 strip_inheriting_ctors (tree dfn)
 500 {
 501   if (!flag_new_inheriting_ctors)
 502     return dfn;
 503   tree fn = dfn;
 504   while (tree inh = DECL_INHERITED_CTOR (fn))
 505     {
 506       inh = OVL_CURRENT (inh);
 507       fn = inh;
 508     }
 509   if (TREE_CODE (fn) == TEMPLATE_DECL
 510       && TREE_CODE (dfn) == FUNCTION_DECL)
 511     fn = DECL_TEMPLATE_RESULT (fn);
 512   return fn;
 513 }
 514
 515 /* Find the binfo for the base subobject of BINFO being initialized by
 516    inherited constructor FNDECL (a member of a direct base of BINFO).  */
 517
 518 static tree inherited_ctor_binfo (tree, tree);
 519 static tree
 520 inherited_ctor_binfo_1 (tree binfo, tree fndecl)
 521 {
 522   tree base = DECL_CONTEXT (fndecl);
 523   tree base_binfo;
 524   for (int i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
 525     if (BINFO_TYPE (base_binfo) == base)
 526       return inherited_ctor_binfo (base_binfo, fndecl);
 527
 528   gcc_unreachable();
 529 }
 530
 531 /* Find the binfo for the base subobject of BINFO being initialized by
 532    inheriting constructor FNDECL (a member of BINFO), or BINFO if FNDECL is not
 533    an inheriting constructor.  */
 534
 535 static tree
 536 inherited_ctor_binfo (tree binfo, tree fndecl)
 537 {
 538   tree inh = DECL_INHERITED_CTOR (fndecl);
 539   if (!inh)
 540     return binfo;
 541
 542   tree results = NULL_TREE;
 543   for (; inh; inh = OVL_NEXT (inh))
 544     {
 545       tree one = inherited_ctor_binfo_1 (binfo, OVL_CURRENT (inh));
 546       if (!results)
 547         results = one;
 548       else if (one != results)
 549         results = tree_cons (NULL_TREE, one, results);
 550     }
 551   return results;
 552 }
 553
 554 /* Find the binfo for the base subobject being initialized by inheriting
 555    constructor FNDECL, or NULL_TREE if FNDECL is not an inheriting
 556    constructor.  */
 557
 558 tree
 559 inherited_ctor_binfo (tree fndecl)
 560 {
 561   if (!DECL_INHERITED_CTOR (fndecl))
 562     return NULL_TREE;
 563   tree binfo = TYPE_BINFO (DECL_CONTEXT (fndecl));
 564   return inherited_ctor_binfo (binfo, fndecl);
 565 }
 566
 567 /* True if we should omit all user-declared parameters from constructor FN,
 568    because it is a base clone of a ctor inherited from a virtual base.  */
 569
 570 bool
 571 ctor_omit_inherited_parms (tree fn)
 572 {
 573   if (!flag_new_inheriting_ctors)
 574     /* We only optimize away the parameters in the new model.  */
 575     return false;
 576   if (!DECL_BASE_CONSTRUCTOR_P (fn)
 577       || !CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fn)))
 578     return false;
 579   if (FUNCTION_FIRST_USER_PARMTYPE (DECL_ORIGIN (fn)) == void_list_node)
 580     /* No user-declared parameters to omit.  */
 581     return false;
 582   tree binfo = inherited_ctor_binfo (fn);
 583   for (; binfo; binfo = BINFO_INHERITANCE_CHAIN (binfo))
 584     if (BINFO_VIRTUAL_P (binfo))
 585       return true;
 586   return false;
 587 }
 588
 589 /* True iff constructor(s) INH inherited into BINFO initializes INIT_BINFO.
 590    This can be true for multiple virtual bases as well as one direct
 591    non-virtual base.  */
 592
 593 static bool
 594 binfo_inherited_from (tree binfo, tree init_binfo, tree inh)
 595 {
 596   /* inh is an OVERLOAD if we inherited the same constructor along
 597      multiple paths, check all of them.  */
 598   for (; inh; inh = OVL_NEXT (inh))
 599     {
 600       tree fn = OVL_CURRENT (inh);
 601       tree base = DECL_CONTEXT (fn);
 602       tree base_binfo = NULL_TREE;
 603       for (int i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
 604         if (BINFO_TYPE (base_binfo) == base)
 605           break;
 606       if (base_binfo == init_binfo
 607           || (flag_new_inheriting_ctors
 608               && binfo_inherited_from (base_binfo, init_binfo,
 609                                        DECL_INHERITED_CTOR (fn))))
 610         return true;
 611     }
 612   return false;
 613 }
 614
 615 /* Subroutine of do_build_copy_constructor: Add a mem-initializer for BINFO
 616    given the parameter or parameters PARM, possibly inherited constructor
 617    base INH, or move flag MOVE_P.  */
 618
 619 static tree
 620 add_one_base_init (tree binfo, tree parm, bool move_p, tree inh,
 621                    tree member_init_list)
 622 {
 623   tree init;
 624   if (inh)
 625     {
 626       /* An inheriting constructor only has a mem-initializer for
 627          the base it inherits from.  */
 628       if (!binfo_inherited_from (TYPE_BINFO (current_class_type), binfo, inh))
 629         return member_init_list;
 630
 631       tree *p = &init;
 632       init = NULL_TREE;
 633       for (; parm; parm = DECL_CHAIN (parm))
 634         {
 635           tree exp = forward_parm (parm);
 636           *p = build_tree_list (NULL_TREE, exp);
 637           p = &TREE_CHAIN (*p);
 638         }
 639     }
 640   else
 641     {
 642       init = build_base_path (PLUS_EXPR, parm, binfo, 1,
 643                               tf_warning_or_error);
 644       if (move_p)
 645         init = move (init);
 646       init = build_tree_list (NULL_TREE, init);
 647     }
 648   return tree_cons (binfo, init, member_init_list);
 649 }
 650
 651 /* Generate code for default X(X&) or X(X&&) constructor or an inheriting
 652    constructor.  */
 653
 654 static void
 655 do_build_copy_constructor (tree fndecl)
 656 {
 657   tree parm = FUNCTION_FIRST_USER_PARM (fndecl);
 658   bool move_p = DECL_MOVE_CONSTRUCTOR_P (fndecl);
 659   bool trivial = trivial_fn_p (fndecl);
 660   tree inh = DECL_INHERITED_CTOR (fndecl);
 661
 662   if (!inh)
 663     parm = convert_from_reference (parm);
 664
 665   if (trivial)
 666     {
 667       if (is_empty_class (current_class_type))
 668         /* Don't copy the padding byte; it might not have been allocated
 669            if *this is a base subobject.  */;
 670       else if (tree_int_cst_equal (TYPE_SIZE (current_class_type),
 671                                    CLASSTYPE_SIZE (current_class_type)))
 672         {
 673           tree t = build2 (INIT_EXPR, void_type_node, current_class_ref, parm);
 674           finish_expr_stmt (t);
 675         }
 676       else
 677         {
 678           /* We must only copy the non-tail padding parts.  */
 679           tree base_size = CLASSTYPE_SIZE_UNIT (current_class_type);
 680           base_size = size_binop (MINUS_EXPR, base_size, size_int (1));
 681           tree array_type = build_array_type (unsigned_char_type_node,
 682                                               build_index_type (base_size));
 683           tree alias_set = build_int_cst (TREE_TYPE (current_class_ptr), 0);
 684           tree lhs = build2 (MEM_REF, array_type,
 685                              current_class_ptr, alias_set);
 686           tree rhs = build2 (MEM_REF, array_type,
 687                              TREE_OPERAND (parm, 0), alias_set);
 688           tree t = build2 (INIT_EXPR, void_type_node, lhs, rhs);
 689           finish_expr_stmt (t);
 690         }
 691     }
 692   else
 693     {
 694       tree fields = TYPE_FIELDS (current_class_type);
 695       tree member_init_list = NULL_TREE;
 696       int cvquals = cp_type_quals (TREE_TYPE (parm));
 697       int i;
 698       tree binfo, base_binfo;
 699       tree init;
 700       vec<tree, va_gc> *vbases;
 701
 702       /* Initialize all the base-classes with the parameter converted
 703          to their type so that we get their copy constructor and not
 704          another constructor that takes current_class_type.  We must
 705          deal with the binfo's directly as a direct base might be
 706          inaccessible due to ambiguity.  */
 707       for (vbases = CLASSTYPE_VBASECLASSES (current_class_type), i = 0;
 708            vec_safe_iterate (vbases, i, &binfo); i++)
 709         {
 710           member_init_list = add_one_base_init (binfo, parm, move_p, inh,
 711                                                 member_init_list);
 712         }
 713
 714       for (binfo = TYPE_BINFO (current_class_type), i = 0;
 715            BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
 716         {
 717           if (BINFO_VIRTUAL_P (base_binfo))
 718             continue;
 719           member_init_list = add_one_base_init (base_binfo, parm, move_p,
 720                                                 inh, member_init_list);
 721         }
 722
 723       for (; fields; fields = DECL_CHAIN (fields))
 724         {
 725           tree field = fields;
 726           tree expr_type;
 727
 728           if (TREE_CODE (field) != FIELD_DECL)
 729             continue;
 730           if (inh)
 731             continue;
 732
 733           expr_type = TREE_TYPE (field);
 734           if (DECL_NAME (field))
 735             {
 736               if (VFIELD_NAME_P (DECL_NAME (field)))
 737                 continue;
 738             }
 739           else if (ANON_AGGR_TYPE_P (expr_type) && TYPE_FIELDS (expr_type))
 740             /* Just use the field; anonymous types can't have
 741                nontrivial copy ctors or assignment ops or this
 742                function would be deleted.  */;
 743           else
 744             continue;
 745
 746           /* Compute the type of "init->field".  If the copy-constructor
 747              parameter is, for example, "const S&", and the type of
 748              the field is "T", then the type will usually be "const
 749              T".  (There are no cv-qualified variants of reference
 750              types.)  */
 751           if (TREE_CODE (expr_type) != REFERENCE_TYPE)
 752             {
 753               int quals = cvquals;
 754
 755               if (DECL_MUTABLE_P (field))
 756                 quals &= ~TYPE_QUAL_CONST;
 757               quals |= cp_type_quals (expr_type);
 758               expr_type = cp_build_qualified_type (expr_type, quals);
 759             }
 760
 761           init = build3 (COMPONENT_REF, expr_type, parm, field, NULL_TREE);
 762           if (move_p && TREE_CODE (expr_type) != REFERENCE_TYPE
 763               /* 'move' breaks bit-fields, and has no effect for scalars.  */
 764               && !scalarish_type_p (expr_type))
 765             init = move (init);
 766           init = build_tree_list (NULL_TREE, init);
 767
 768           member_init_list = tree_cons (field, init, member_init_list);
 769         }
 770       finish_mem_initializers (member_init_list);
 771     }
 772 }
 773
 774 static void
 775 do_build_copy_assign (tree fndecl)
 776 {
 777   tree parm = DECL_CHAIN (DECL_ARGUMENTS (fndecl));
 778   tree compound_stmt;
 779   bool move_p = move_fn_p (fndecl);
 780   bool trivial = trivial_fn_p (fndecl);
 781   int flags = LOOKUP_NORMAL | LOOKUP_NONVIRTUAL | LOOKUP_DEFAULTED;
 782
 783   compound_stmt = begin_compound_stmt (0);
 784   parm = convert_from_reference (parm);
 785
 786   if (trivial
 787       && is_empty_class (current_class_type))
 788     /* Don't copy the padding byte; it might not have been allocated
 789        if *this is a base subobject.  */;
 790   else if (trivial)
 791     {
 792       tree t = build2 (MODIFY_EXPR, void_type_node, current_class_ref, parm);
 793       finish_expr_stmt (t);
 794     }
 795   else
 796     {
 797       tree fields;
 798       int cvquals = cp_type_quals (TREE_TYPE (parm));
 799       int i;
 800       tree binfo, base_binfo;
 801
 802       /* Assign to each of the direct base classes.  */
 803       for (binfo = TYPE_BINFO (current_class_type), i = 0;
 804            BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
 805         {
 806           tree converted_parm;
 807           vec<tree, va_gc> *parmvec;
 808
 809           /* We must convert PARM directly to the base class
 810              explicitly since the base class may be ambiguous.  */
 811           converted_parm = build_base_path (PLUS_EXPR, parm, base_binfo, 1,
 812                                             tf_warning_or_error);
 813           if (move_p)
 814             converted_parm = move (converted_parm);
 815           /* Call the base class assignment operator.  */
 816           parmvec = make_tree_vector_single (converted_parm);
 817           finish_expr_stmt
 818             (build_special_member_call (current_class_ref,
 819                                         cp_assignment_operator_id (NOP_EXPR),
 820                                         &parmvec,
 821                                         base_binfo,
 822                                         flags,
 823                                         tf_warning_or_error));
 824           release_tree_vector (parmvec);
 825         }
 826
 827       /* Assign to each of the non-static data members.  */
 828       for (fields = TYPE_FIELDS (current_class_type);
 829            fields;
 830            fields = DECL_CHAIN (fields))
 831         {
 832           tree comp = current_class_ref;
 833           tree init = parm;
 834           tree field = fields;
 835           tree expr_type;
 836           int quals;
 837
 838           if (TREE_CODE (field) != FIELD_DECL || DECL_ARTIFICIAL (field))
 839             continue;
 840
 841           expr_type = TREE_TYPE (field);
 842
 843           if (CP_TYPE_CONST_P (expr_type))
 844             {
 845               error ("non-static const member %q#D, can%'t use default "
 846                      "assignment operator", field);
 847               continue;
 848             }
 849           else if (TREE_CODE (expr_type) == REFERENCE_TYPE)
 850             {
 851               error ("non-static reference member %q#D, can%'t use "
 852                      "default assignment operator", field);
 853               continue;
 854             }
 855
 856           if (DECL_NAME (field))
 857             {
 858               if (VFIELD_NAME_P (DECL_NAME (field)))
 859                 continue;
 860             }
 861           else if (ANON_AGGR_TYPE_P (expr_type)
 862                    && TYPE_FIELDS (expr_type) != NULL_TREE)
 863             /* Just use the field; anonymous types can't have
 864                nontrivial copy ctors or assignment ops or this
 865                function would be deleted.  */;
 866           else
 867             continue;
 868
 869           comp = build3 (COMPONENT_REF, expr_type, comp, field, NULL_TREE);
 870
 871           /* Compute the type of init->field  */
 872           quals = cvquals;
 873           if (DECL_MUTABLE_P (field))
 874             quals &= ~TYPE_QUAL_CONST;
 875           expr_type = cp_build_qualified_type (expr_type, quals);
 876
 877           init = build3 (COMPONENT_REF, expr_type, init, field, NULL_TREE);
 878           if (move_p && TREE_CODE (expr_type) != REFERENCE_TYPE
 879               /* 'move' breaks bit-fields, and has no effect for scalars.  */
 880               && !scalarish_type_p (expr_type))
 881             init = move (init);
 882
 883           if (DECL_NAME (field))
 884             init = cp_build_modify_expr (input_location, comp, NOP_EXPR, init,
 885                                          tf_warning_or_error);
 886           else
 887             init = build2 (MODIFY_EXPR, TREE_TYPE (comp), comp, init);
 888           finish_expr_stmt (init);
 889         }
 890     }
 891   finish_return_stmt (current_class_ref);
 892   finish_compound_stmt (compound_stmt);
 893 }
 894
 895 /* Synthesize FNDECL, a non-static member function.   */
 896
 897 void
 898 synthesize_method (tree fndecl)
 899 {
 900   bool nested = (current_function_decl != NULL_TREE);
 901   tree context = decl_function_context (fndecl);
 902   bool need_body = true;
 903   tree stmt;
 904   location_t save_input_location = input_location;
 905   int error_count = errorcount;
 906   int warning_count = warningcount + werrorcount;
 907
 908   /* Reset the source location, we might have been previously
 909      deferred, and thus have saved where we were first needed.  */
 910   DECL_SOURCE_LOCATION (fndecl)
 911     = DECL_SOURCE_LOCATION (TYPE_NAME (DECL_CONTEXT (fndecl)));
 912
 913   /* If we've been asked to synthesize a clone, just synthesize the
 914      cloned function instead.  Doing so will automatically fill in the
 915      body for the clone.  */
 916   if (DECL_CLONED_FUNCTION_P (fndecl))
 917     fndecl = DECL_CLONED_FUNCTION (fndecl);
 918
 919   /* We may be in the middle of deferred access check.  Disable
 920      it now.  */
 921   push_deferring_access_checks (dk_no_deferred);
 922
 923   if (! context)
 924     push_to_top_level ();
 925   else if (nested)
 926     push_function_context ();
 927
 928   input_location = DECL_SOURCE_LOCATION (fndecl);
 929
 930   start_preparsed_function (fndecl, NULL_TREE, SF_DEFAULT | SF_PRE_PARSED);
 931   stmt = begin_function_body ();
 932
 933   if (DECL_OVERLOADED_OPERATOR_P (fndecl) == NOP_EXPR)
 934     {
 935       do_build_copy_assign (fndecl);
 936       need_body = false;
 937     }
 938   else if (DECL_CONSTRUCTOR_P (fndecl))
 939     {
 940       tree arg_chain = FUNCTION_FIRST_USER_PARMTYPE (fndecl);
 941       if (arg_chain != void_list_node)
 942         do_build_copy_constructor (fndecl);
 943       else
 944         finish_mem_initializers (NULL_TREE);
 945     }
 946
 947   /* If we haven't yet generated the body of the function, just
 948      generate an empty compound statement.  */
 949   if (need_body)
 950     {
 951       tree compound_stmt;
 952       compound_stmt = begin_compound_stmt (BCS_FN_BODY);
 953       finish_compound_stmt (compound_stmt);
 954     }
 955
 956   finish_function_body (stmt);
 957   expand_or_defer_fn (finish_function (0));
 958
 959   input_location = save_input_location;
 960
 961   if (! context)
 962     pop_from_top_level ();
 963   else if (nested)
 964     pop_function_context ();
 965
 966   pop_deferring_access_checks ();
 967
 968   if (error_count != errorcount || warning_count != warningcount + werrorcount)
 969     inform (input_location, "synthesized method %qD first required here ",
 970             fndecl);
 971 }
 972
 973 /* Build a reference to type TYPE with cv-quals QUALS, which is an
 974    rvalue if RVALUE is true.  */
 975
 976 static tree
 977 build_stub_type (tree type, int quals, bool rvalue)
 978 {
 979   tree argtype = cp_build_qualified_type (type, quals);
 980   return cp_build_reference_type (argtype, rvalue);
 981 }
 982
 983 /* Build a dummy glvalue from dereferencing a dummy reference of type
 984    REFTYPE.  */
 985
 986 static tree
 987 build_stub_object (tree reftype)
 988 {
 989   if (TREE_CODE (reftype) != REFERENCE_TYPE)
 990     reftype = cp_build_reference_type (reftype, /*rval*/true);
 991   tree stub = build1 (CONVERT_EXPR, reftype, integer_one_node);
 992   return convert_from_reference (stub);
 993 }
 994
 995 /* Determine which function will be called when looking up NAME in TYPE,
 996    called with a single ARGTYPE argument, or no argument if ARGTYPE is
 997    null.  FLAGS and COMPLAIN are as for build_new_method_call.
 998
 999    Returns a FUNCTION_DECL if all is well.
1000    Returns NULL_TREE if overload resolution failed.
1001    Returns error_mark_node if the chosen function cannot be called.  */
1002
1003 static tree
1004 locate_fn_flags (tree type, tree name, tree argtype, int flags,
1005                  tsubst_flags_t complain)
1006 {
1007   tree ob, fn, fns, binfo, rval;
1008   vec<tree, va_gc> *args;
1009
1010   if (TYPE_P (type))
1011     binfo = TYPE_BINFO (type);
1012   else
1013     {
1014       binfo = type;
1015       type = BINFO_TYPE (binfo);
1016     }
1017
1018   ob = build_stub_object (cp_build_reference_type (type, false));
1019   args = make_tree_vector ();
1020   if (argtype)
1021     {
1022       if (TREE_CODE (argtype) == TREE_LIST)
1023         {
1024           for (tree elt = argtype; elt && elt != void_list_node;
1025                elt = TREE_CHAIN (elt))
1026             {
1027               tree type = TREE_VALUE (elt);
1028               tree arg = build_stub_object (type);
1029               vec_safe_push (args, arg);
1030             }
1031         }
1032       else
1033         {
1034           tree arg = build_stub_object (argtype);
1035           args->quick_push (arg);
1036         }
1037     }
1038
1039   fns = lookup_fnfields (binfo, name, 0);
1040   rval = build_new_method_call (ob, fns, &args, binfo, flags, &fn, complain);
1041
1042   release_tree_vector (args);
1043   if (fn && rval == error_mark_node)
1044     return rval;
1045   else
1046     return fn;
1047 }
1048
1049 /* Locate the dtor of TYPE.  */
1050
1051 tree
1052 get_dtor (tree type, tsubst_flags_t complain)
1053 {
1054   tree fn = locate_fn_flags (type, complete_dtor_identifier, NULL_TREE,
1055                              LOOKUP_NORMAL, complain);
1056   if (fn == error_mark_node)
1057     return NULL_TREE;
1058   return fn;
1059 }
1060
1061 /* Locate the default ctor of TYPE.  */
1062
1063 tree
1064 locate_ctor (tree type)
1065 {
1066   tree fn;
1067
1068   push_deferring_access_checks (dk_no_check);
1069   fn = locate_fn_flags (type, complete_ctor_identifier, NULL_TREE,
1070                         LOOKUP_SPECULATIVE, tf_none);
1071   pop_deferring_access_checks ();
1072   if (fn == error_mark_node)
1073     return NULL_TREE;
1074   return fn;
1075 }
1076
1077 /* Likewise, but give any appropriate errors.  */
1078
1079 tree
1080 get_default_ctor (tree type)
1081 {
1082   tree fn = locate_fn_flags (type, complete_ctor_identifier, NULL_TREE,
1083                              LOOKUP_NORMAL, tf_warning_or_error);
1084   if (fn == error_mark_node)
1085     return NULL_TREE;
1086   return fn;
1087 }
1088
1089 /* Locate the copy ctor of TYPE.  */
1090
1091 tree
1092 get_copy_ctor (tree type, tsubst_flags_t complain)
1093 {
1094   int quals = (TYPE_HAS_CONST_COPY_CTOR (type)
1095                ? TYPE_QUAL_CONST : TYPE_UNQUALIFIED);
1096   tree argtype = build_stub_type (type, quals, false);
1097   tree fn = locate_fn_flags (type, complete_ctor_identifier, argtype,
1098                              LOOKUP_NORMAL, complain);
1099   if (fn == error_mark_node)
1100     return NULL_TREE;
1101   return fn;
1102 }
1103
1104 /* Locate the copy assignment operator of TYPE.  */
1105
1106 tree
1107 get_copy_assign (tree type)
1108 {
1109   int quals = (TYPE_HAS_CONST_COPY_ASSIGN (type)
1110                ? TYPE_QUAL_CONST : TYPE_UNQUALIFIED);
1111   tree argtype = build_stub_type (type, quals, false);
1112   tree fn = locate_fn_flags (type, cp_assignment_operator_id (NOP_EXPR), argtype,
1113                              LOOKUP_NORMAL, tf_warning_or_error);
1114   if (fn == error_mark_node)
1115     return NULL_TREE;
1116   return fn;
1117 }
1118
1119 /* walk_tree helper function for is_trivially_xible.  If *TP is a call,
1120    return it if it calls something other than a trivial special member
1121    function.  */
1122
1123 static tree
1124 check_nontriv (tree *tp, int *, void *)
1125 {
1126   tree fn = cp_get_callee (*tp);
1127   if (fn == NULL_TREE)
1128     return NULL_TREE;
1129
1130   if (TREE_CODE (fn) == ADDR_EXPR)
1131     fn = TREE_OPERAND (fn, 0);
1132
1133   if (TREE_CODE (fn) != FUNCTION_DECL
1134       || !trivial_fn_p (fn))
1135     return fn;
1136   return NULL_TREE;
1137 }
1138
1139 /* Return declval<T>() = declval<U>() treated as an unevaluated operand.  */
1140
1141 static tree
1142 assignable_expr (tree to, tree from)
1143 {
1144   ++cp_unevaluated_operand;
1145   to = build_stub_object (to);
1146   from = build_stub_object (from);
1147   tree r = cp_build_modify_expr (input_location, to, NOP_EXPR, from, tf_none);
1148   --cp_unevaluated_operand;
1149   return r;
1150 }
1151
1152 /* The predicate condition for a template specialization
1153    is_constructible<T, Args...> shall be satisfied if and only if the
1154    following variable definition would be well-formed for some invented
1155    variable t: T t(create<Args>()...);
1156
1157    Return something equivalent in well-formedness and triviality.  */
1158
1159 static tree
1160 constructible_expr (tree to, tree from)
1161 {
1162   tree expr;
1163   if (CLASS_TYPE_P (to))
1164     {
1165       tree ctype = to;
1166       vec<tree, va_gc> *args = NULL;
1167       if (TREE_CODE (to) != REFERENCE_TYPE)
1168         to = cp_build_reference_type (to, /*rval*/false);
1169       tree ob = build_stub_object (to);
1170       for (; from; from = TREE_CHAIN (from))
1171         vec_safe_push (args, build_stub_object (TREE_VALUE (from)));
1172       expr = build_special_member_call (ob, complete_ctor_identifier, &args,
1173                                         ctype, LOOKUP_NORMAL, tf_none);
1174       if (expr == error_mark_node)
1175         return error_mark_node;
1176       /* The current state of the standard vis-a-vis LWG 2116 is that
1177          is_*constructible involves destruction as well.  */
1178       if (type_build_dtor_call (ctype))
1179         {
1180           tree dtor = build_special_member_call (ob, complete_dtor_identifier,
1181                                                  NULL, ctype, LOOKUP_NORMAL,
1182                                                  tf_none);
1183           if (dtor == error_mark_node)
1184             return error_mark_node;
1185           if (!TYPE_HAS_TRIVIAL_DESTRUCTOR (ctype))
1186             expr = build2 (COMPOUND_EXPR, void_type_node, expr, dtor);
1187         }
1188     }
1189   else
1190     {
1191       if (from == NULL_TREE)
1192         return build_value_init (to, tf_none);
1193       else if (TREE_CHAIN (from))
1194         return error_mark_node; // too many initializers
1195       from = build_stub_object (TREE_VALUE (from));
1196       expr = perform_direct_initialization_if_possible (to, from,
1197                                                         /*cast*/false,
1198                                                         tf_none);
1199     }
1200   return expr;
1201 }
1202
1203 /* Returns true iff TO is trivially assignable (if CODE is MODIFY_EXPR) or
1204    constructible (otherwise) from FROM, which is a single type for
1205    assignment or a list of types for construction.  */
1206
1207 bool
1208 is_trivially_xible (enum tree_code code, tree to, tree from)
1209 {
1210   tree expr;
1211   if (code == MODIFY_EXPR)
1212     expr = assignable_expr (to, from);
1213   else if (from && TREE_CHAIN (from))
1214     return false; // only 0- and 1-argument ctors can be trivial
1215   else
1216     expr = constructible_expr (to, from);
1217
1218   if (expr == error_mark_node)
1219     return false;
1220   tree nt = cp_walk_tree_without_duplicates (&expr, check_nontriv, NULL);
1221   return !nt;
1222 }
1223
1224 /* Subroutine of synthesized_method_walk.  Update SPEC_P, TRIVIAL_P and
1225    DELETED_P or give an error message MSG with argument ARG.  */
1226
1227 static void
1228 process_subob_fn (tree fn, tree *spec_p, bool *trivial_p,
1229                   bool *deleted_p, bool *constexpr_p,
1230                   bool diag, tree arg, bool dtor_from_ctor = false)
1231 {
1232   if (!fn || fn == error_mark_node)
1233     {
1234       if (deleted_p)
1235         *deleted_p = true;
1236       return;
1237     }
1238
1239   if (spec_p)
1240     {
1241       maybe_instantiate_noexcept (fn);
1242       tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn));
1243       *spec_p = merge_exception_specifiers (*spec_p, raises);
1244     }
1245
1246   if (!trivial_fn_p (fn) && !dtor_from_ctor)
1247     {
1248       if (trivial_p)
1249         *trivial_p = false;
1250       if (TREE_CODE (arg) == FIELD_DECL
1251           && TREE_CODE (DECL_CONTEXT (arg)) == UNION_TYPE)
1252         {
1253           if (deleted_p)
1254             *deleted_p = true;
1255           if (diag)
1256             error ("union member %q+D with non-trivial %qD", arg, fn);
1257         }
1258     }
1259
1260   if (constexpr_p && !DECL_DECLARED_CONSTEXPR_P (fn))
1261     {
1262       *constexpr_p = false;
1263       if (diag)
1264         {
1265           inform (DECL_SOURCE_LOCATION (fn),
1266                   "defaulted constructor calls non-constexpr %qD", fn);
1267           explain_invalid_constexpr_fn (fn);
1268         }
1269     }
1270 }
1271
1272 /* Subroutine of synthesized_method_walk to allow recursion into anonymous
1273    aggregates.  If DTOR_FROM_CTOR is true, we're walking subobject destructors
1274    called from a synthesized constructor, in which case we don't consider
1275    the triviality of the subobject destructor.  */
1276
1277 static void
1278 walk_field_subobs (tree fields, tree fnname, special_function_kind sfk,
1279                    int quals, bool copy_arg_p, bool move_p,
1280                    bool assign_p, tree *spec_p, bool *trivial_p,
1281                    bool *deleted_p, bool *constexpr_p,
1282                    bool diag, int flags, tsubst_flags_t complain,
1283                    bool dtor_from_ctor)
1284 {
1285   tree field;
1286   for (field = fields; field; field = DECL_CHAIN (field))
1287     {
1288       tree mem_type, argtype, rval;
1289
1290       if (TREE_CODE (field) != FIELD_DECL
1291           || DECL_ARTIFICIAL (field))
1292         continue;
1293
1294       mem_type = strip_array_types (TREE_TYPE (field));
1295       if (assign_p)
1296         {
1297           bool bad = true;
1298           if (CP_TYPE_CONST_P (mem_type) && !CLASS_TYPE_P (mem_type))
1299             {
1300               if (diag)
1301                 error ("non-static const member %q#D, can%'t use default "
1302                        "assignment operator", field);
1303             }
1304           else if (TREE_CODE (mem_type) == REFERENCE_TYPE)
1305             {
1306               if (diag)
1307                 error ("non-static reference member %q#D, can%'t use "
1308                        "default assignment operator", field);
1309             }
1310           else
1311             bad = false;
1312
1313           if (bad && deleted_p)
1314             *deleted_p = true;
1315         }
1316       else if (sfk == sfk_constructor)
1317         {
1318           bool bad;
1319
1320           if (DECL_INITIAL (field))
1321             {
1322               if (diag && DECL_INITIAL (field) == error_mark_node)
1323                 inform (DECL_SOURCE_LOCATION (field),
1324                         "initializer for %q#D is invalid", field);
1325               if (trivial_p)
1326                 *trivial_p = false;
1327               /* Core 1351: If the field has an NSDMI that could throw, the
1328                  default constructor is noexcept(false).  */
1329               if (spec_p)
1330                 {
1331                   tree nsdmi = get_nsdmi (field, /*ctor*/false);
1332                   if (!expr_noexcept_p (nsdmi, complain))
1333                     *spec_p = noexcept_false_spec;
1334                 }
1335               /* Don't do the normal processing.  */
1336               continue;
1337             }
1338
1339           bad = false;
1340           if (CP_TYPE_CONST_P (mem_type)
1341               && default_init_uninitialized_part (mem_type))
1342             {
1343               if (diag)
1344                 {
1345                   error ("uninitialized const member in %q#T",
1346                          current_class_type);
1347                   inform (DECL_SOURCE_LOCATION (field),
1348                           "%q#D should be initialized", field);
1349                 }
1350               bad = true;
1351             }
1352           else if (TREE_CODE (mem_type) == REFERENCE_TYPE)
1353             {
1354               if (diag)
1355                 {
1356                   error ("uninitialized reference member in %q#T",
1357                          current_class_type);
1358                   inform (DECL_SOURCE_LOCATION (field),
1359                           "%q#D should be initialized", field);
1360                 }
1361               bad = true;
1362             }
1363
1364           if (bad && deleted_p)
1365             *deleted_p = true;
1366
1367           /* For an implicitly-defined default constructor to be constexpr,
1368              every member must have a user-provided default constructor or
1369              an explicit initializer.  */
1370           if (constexpr_p && !CLASS_TYPE_P (mem_type)
1371               && TREE_CODE (DECL_CONTEXT (field)) != UNION_TYPE)
1372             {
1373               *constexpr_p = false;
1374               if (diag)
1375                 inform (DECL_SOURCE_LOCATION (field),
1376                         "defaulted default constructor does not "
1377                         "initialize %q#D", field);
1378             }
1379         }
1380       else if (sfk == sfk_copy_constructor)
1381         {
1382           /* 12.8p11b5 */
1383           if (TREE_CODE (mem_type) == REFERENCE_TYPE
1384               && TYPE_REF_IS_RVALUE (mem_type))
1385             {
1386               if (diag)
1387                 error ("copying non-static data member %q#D of rvalue "
1388                        "reference type", field);
1389               if (deleted_p)
1390                 *deleted_p = true;
1391             }
1392         }
1393
1394       if (!CLASS_TYPE_P (mem_type))
1395         continue;
1396
1397       if (ANON_AGGR_TYPE_P (mem_type))
1398         {
1399           walk_field_subobs (TYPE_FIELDS (mem_type), fnname, sfk, quals,
1400                              copy_arg_p, move_p, assign_p, spec_p, trivial_p,
1401                              deleted_p, constexpr_p,
1402                              diag, flags, complain, dtor_from_ctor);
1403           continue;
1404         }
1405
1406       if (copy_arg_p)
1407         {
1408           int mem_quals = cp_type_quals (mem_type) | quals;
1409           if (DECL_MUTABLE_P (field))
1410             mem_quals &= ~TYPE_QUAL_CONST;
1411           argtype = build_stub_type (mem_type, mem_quals, move_p);
1412         }
1413       else
1414         argtype = NULL_TREE;
1415
1416       rval = locate_fn_flags (mem_type, fnname, argtype, flags, complain);
1417
1418       process_subob_fn (rval, spec_p, trivial_p, deleted_p,
1419                         constexpr_p, diag, field, dtor_from_ctor);
1420     }
1421 }
1422
1423 /* Base walker helper for synthesized_method_walk.  Inspect a direct
1424    or virtual base.  BINFO is the parent type's binfo.  BASE_BINFO is
1425    the base binfo of interests.  All other parms are as for
1426    synthesized_method_walk, or its local vars.  */
1427
1428 static tree
1429 synthesized_method_base_walk (tree binfo, tree base_binfo,
1430                               int quals, bool copy_arg_p,
1431                               bool move_p, bool ctor_p,
1432                               tree inheriting_ctor, tree inherited_parms,
1433                               tree fnname, int flags, bool diag,
1434                               tree *spec_p, bool *trivial_p,
1435                               bool *deleted_p, bool *constexpr_p)
1436 {
1437   bool inherited_binfo = false;
1438   tree argtype = NULL_TREE;
1439   deferring_kind defer = dk_no_deferred;
1440
1441   if (copy_arg_p)
1442     argtype = build_stub_type (BINFO_TYPE (base_binfo), quals, move_p);
1443   else if ((inherited_binfo
1444             = binfo_inherited_from (binfo, base_binfo, inheriting_ctor)))
1445     {
1446       argtype = inherited_parms;
1447       /* Don't check access on the inherited constructor.  */
1448       if (flag_new_inheriting_ctors)
1449         defer = dk_deferred;
1450     }
1451   /* To be conservative, ignore access to the base dtor that
1452      DR1658 instructs us to ignore.  See the comment in
1453      synthesized_method_walk.  */
1454   else if (cxx_dialect >= cxx14 && fnname == complete_dtor_identifier
1455            && BINFO_VIRTUAL_P (base_binfo)
1456            && ABSTRACT_CLASS_TYPE_P (BINFO_TYPE (binfo)))
1457     defer = dk_no_check;
1458
1459   if (defer != dk_no_deferred)
1460     push_deferring_access_checks (defer);
1461   tree rval = locate_fn_flags (base_binfo, fnname, argtype, flags,
1462                                diag ? tf_warning_or_error : tf_none);
1463   if (defer != dk_no_deferred)
1464     pop_deferring_access_checks ();
1465
1466   process_subob_fn (rval, spec_p, trivial_p, deleted_p,
1467                     constexpr_p, diag, BINFO_TYPE (base_binfo));
1468   if (ctor_p &&
1469       (!BINFO_VIRTUAL_P (base_binfo)
1470        || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (BINFO_TYPE (base_binfo))))
1471     {
1472       /* In a constructor we also need to check the subobject
1473          destructors for cleanup of partially constructed objects.  */
1474       tree dtor = locate_fn_flags (base_binfo, complete_dtor_identifier,
1475                                    NULL_TREE, flags,
1476                                    diag ? tf_warning_or_error : tf_none);
1477           /* Note that we don't pass down trivial_p; the subobject
1478              destructors don't affect triviality of the constructor.  Nor
1479              do they affect constexpr-ness (a constant expression doesn't
1480              throw) or exception-specification (a throw from one of the
1481              dtors would be a double-fault).  */
1482       process_subob_fn (dtor, NULL, NULL, deleted_p, NULL, false,
1483                         BINFO_TYPE (base_binfo), /*dtor_from_ctor*/true);
1484     }
1485
1486   return rval;
1487 }
1488
1489 /* The caller wants to generate an implicit declaration of SFK for
1490    CTYPE which is const if relevant and CONST_P is set.  If SPEC_P,
1491    TRIVIAL_P, DELETED_P or CONSTEXPR_P are non-null, set their
1492    referent appropriately.  If DIAG is true, we're either being called
1493    from maybe_explain_implicit_delete to give errors, or if
1494    CONSTEXPR_P is non-null, from explain_invalid_constexpr_fn.  */
1495
1496 static void
1497 synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
1498                          tree *spec_p, bool *trivial_p, bool *deleted_p,
1499                          bool *constexpr_p, bool diag,
1500                          tree inheriting_ctor, tree inherited_parms)
1501 {
1502   tree binfo, base_binfo, fnname;
1503   int i;
1504
1505   if (spec_p)
1506     *spec_p = (cxx_dialect >= cxx11 ? noexcept_true_spec : empty_except_spec);
1507
1508   if (deleted_p)
1509     {
1510       /* "The closure type associated with a lambda-expression has a deleted
1511          default constructor and a deleted copy assignment operator."
1512          This is diagnosed in maybe_explain_implicit_delete.  */
1513       if (LAMBDA_TYPE_P (ctype)
1514           && (sfk == sfk_constructor
1515               || sfk == sfk_copy_assignment))
1516         {
1517           *deleted_p = true;
1518           return;
1519         }
1520
1521       *deleted_p = false;
1522     }
1523
1524   bool ctor_p = false;
1525   bool assign_p = false;
1526   bool check_vdtor = false;
1527   switch (sfk)
1528     {
1529     case sfk_move_assignment:
1530     case sfk_copy_assignment:
1531       assign_p = true;
1532       fnname = cp_assignment_operator_id (NOP_EXPR);
1533       break;
1534
1535     case sfk_destructor:
1536       check_vdtor = true;
1537       /* The synthesized method will call base dtors, but check complete
1538          here to avoid having to deal with VTT.  */
1539       fnname = complete_dtor_identifier;
1540       break;
1541
1542     case sfk_constructor:
1543     case sfk_move_constructor:
1544     case sfk_copy_constructor:
1545     case sfk_inheriting_constructor:
1546       ctor_p = true;
1547       fnname = complete_ctor_identifier;
1548       break;
1549
1550     default:
1551       gcc_unreachable ();
1552     }
1553
1554   gcc_assert ((sfk == sfk_inheriting_constructor)
1555               == (inheriting_ctor != NULL_TREE));
1556
1557   /* If that user-written default constructor would satisfy the
1558      requirements of a constexpr constructor (7.1.5), the
1559      implicitly-defined default constructor is constexpr.
1560
1561      The implicitly-defined copy/move assignment operator is constexpr if
1562       - X is a literal type, and
1563       - the assignment operator selected to copy/move each direct base class
1564         subobject is a constexpr function, and
1565       - for each non-static data member of X that is of class type (or array
1566         thereof), the assignment operator selected to copy/move that
1567         member is a constexpr function.  */
1568   if (constexpr_p)
1569     *constexpr_p = ctor_p || (assign_p && cxx_dialect >= cxx14);
1570
1571   bool move_p = false;
1572   bool copy_arg_p = false;
1573   switch (sfk)
1574     {
1575     case sfk_constructor:
1576     case sfk_destructor:
1577     case sfk_inheriting_constructor:
1578       break;
1579
1580     case sfk_move_constructor:
1581     case sfk_move_assignment:
1582       move_p = true;
1583       /* FALLTHRU */
1584     case sfk_copy_constructor:
1585     case sfk_copy_assignment:
1586       copy_arg_p = true;
1587       break;
1588
1589     default:
1590       gcc_unreachable ();
1591     }
1592
1593   bool expected_trivial = type_has_trivial_fn (ctype, sfk);
1594   if (trivial_p)
1595     *trivial_p = expected_trivial;
1596
1597   /* The TYPE_HAS_COMPLEX_* flags tell us about constraints from base
1598      class versions and other properties of the type.  But a subobject
1599      class can be trivially copyable and yet have overload resolution
1600      choose a template constructor for initialization, depending on
1601      rvalueness and cv-quals.  And furthermore, a member in a base might
1602      be trivial but deleted or otherwise not callable.  So we can't exit
1603      early in C++0x.  The same considerations apply in C++98/03, but
1604      there the definition of triviality does not consider overload
1605      resolution, so a constructor can be trivial even if it would otherwise
1606      call a non-trivial constructor.  */
1607   if (expected_trivial
1608       && (!copy_arg_p || cxx_dialect < cxx11))
1609     {
1610       if (constexpr_p && sfk == sfk_constructor)
1611         {
1612           bool cx = trivial_default_constructor_is_constexpr (ctype);
1613           *constexpr_p = cx;
1614           if (diag && !cx && TREE_CODE (ctype) == UNION_TYPE)
1615             /* A trivial constructor doesn't have any NSDMI.  */
1616             inform (input_location, "defaulted default constructor does "
1617                     "not initialize any non-static data member");
1618         }
1619       if (!diag && cxx_dialect < cxx11)
1620         return;
1621     }
1622
1623   ++cp_unevaluated_operand;
1624   ++c_inhibit_evaluation_warnings;
1625   push_deferring_access_checks (dk_no_deferred);
1626
1627   tree scope = push_scope (ctype);
1628
1629   int flags = LOOKUP_NORMAL | LOOKUP_SPECULATIVE;
1630   if (!inheriting_ctor)
1631     flags |= LOOKUP_DEFAULTED;
1632
1633   tsubst_flags_t complain = diag ? tf_warning_or_error : tf_none;
1634   int quals = const_p ? TYPE_QUAL_CONST : TYPE_UNQUALIFIED;
1635
1636   for (binfo = TYPE_BINFO (ctype), i = 0;
1637        BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
1638     {
1639       if (!assign_p && BINFO_VIRTUAL_P (base_binfo))
1640         /* We'll handle virtual bases below.  */
1641         continue;
1642
1643       tree fn = synthesized_method_base_walk (binfo, base_binfo, quals,
1644                                               copy_arg_p, move_p, ctor_p,
1645                                               inheriting_ctor,
1646                                               inherited_parms,
1647                                               fnname, flags, diag,
1648                                               spec_p, trivial_p,
1649                                               deleted_p, constexpr_p);
1650
1651       if (diag && assign_p && move_p
1652           && BINFO_VIRTUAL_P (base_binfo)
1653           && fn && TREE_CODE (fn) == FUNCTION_DECL
1654           && move_fn_p (fn) && !trivial_fn_p (fn)
1655           && vbase_has_user_provided_move_assign (BINFO_TYPE (base_binfo)))
1656         warning (OPT_Wvirtual_move_assign,
1657                  "defaulted move assignment for %qT calls a non-trivial "
1658                  "move assignment operator for virtual base %qT",
1659                  ctype, BINFO_TYPE (base_binfo));
1660
1661       if (check_vdtor && type_has_virtual_destructor (BINFO_TYPE (base_binfo)))
1662         {
1663           fn = locate_fn_flags (ctype, cp_operator_id (DELETE_EXPR),
1664                                 ptr_type_node, flags, complain);
1665           /* Unlike for base ctor/op=/dtor, for operator delete it's fine
1666              to have a null fn (no class-specific op delete).  */
1667           if (fn && fn == error_mark_node && deleted_p)
1668             *deleted_p = true;
1669           check_vdtor = false;
1670         }
1671     }
1672
1673   vec<tree, va_gc> *vbases = CLASSTYPE_VBASECLASSES (ctype);
1674   if (assign_p)
1675     /* Already examined vbases above.  */;
1676   else if (vec_safe_is_empty (vbases))
1677     /* No virtual bases to worry about.  */;
1678   else if (ABSTRACT_CLASS_TYPE_P (ctype) && cxx_dialect >= cxx14
1679            /* DR 1658 specifies that vbases of abstract classes are
1680               ignored for both ctors and dtors.  However, that breaks
1681               virtual dtor overriding when the ignored base has a
1682               throwing destructor.  So, ignore that piece of 1658.  A
1683               defect has been filed (no number yet).  */
1684            && sfk != sfk_destructor)
1685     /* Vbase cdtors are not relevant.  */;
1686   else
1687     {
1688       if (constexpr_p)
1689         *constexpr_p = false;
1690
1691       FOR_EACH_VEC_ELT (*vbases, i, base_binfo)
1692         synthesized_method_base_walk (binfo, base_binfo, quals,
1693                                       copy_arg_p, move_p, ctor_p,
1694                                       inheriting_ctor, inherited_parms,
1695                                       fnname, flags, diag,
1696                                       spec_p, trivial_p,
1697                                       deleted_p, constexpr_p);
1698     }
1699
1700   /* Now handle the non-static data members.  */
1701   walk_field_subobs (TYPE_FIELDS (ctype), fnname, sfk, quals,
1702                      copy_arg_p, move_p, assign_p, spec_p, trivial_p,
1703                      deleted_p, constexpr_p,
1704                      diag, flags, complain, /*dtor_from_ctor*/false);
1705   if (ctor_p)
1706     walk_field_subobs (TYPE_FIELDS (ctype), complete_dtor_identifier,
1707                        sfk_destructor, TYPE_UNQUALIFIED, false,
1708                        false, false, NULL, NULL,
1709                        deleted_p, NULL,
1710                        false, flags, complain, /*dtor_from_ctor*/true);
1711
1712   pop_scope (scope);
1713
1714   pop_deferring_access_checks ();
1715   --cp_unevaluated_operand;
1716   --c_inhibit_evaluation_warnings;
1717 }
1718
1719 /* DECL is a defaulted function whose exception specification is now
1720    needed.  Return what it should be.  */
1721
1722 tree
1723 get_defaulted_eh_spec (tree decl)
1724 {
1725   if (DECL_CLONED_FUNCTION_P (decl))
1726     decl = DECL_CLONED_FUNCTION (decl);
1727   special_function_kind sfk = special_function_p (decl);
1728   tree ctype = DECL_CONTEXT (decl);
1729   tree parms = FUNCTION_FIRST_USER_PARMTYPE (decl);
1730   tree parm_type = TREE_VALUE (parms);
1731   bool const_p = CP_TYPE_CONST_P (non_reference (parm_type));
1732   tree spec = empty_except_spec;
1733   synthesized_method_walk (ctype, sfk, const_p, &spec, NULL, NULL,
1734                            NULL, false, DECL_INHERITED_CTOR (decl),
1735                            parms);
1736   return spec;
1737 }
1738
1739 /* DECL is a deleted function.  If it's implicitly deleted, explain why and
1740    return true; else return false.  */
1741
1742 bool
1743 maybe_explain_implicit_delete (tree decl)
1744 {
1745   /* If decl is a clone, get the primary variant.  */
1746   decl = DECL_ORIGIN (decl);
1747   gcc_assert (DECL_DELETED_FN (decl));
1748   if (DECL_DEFAULTED_FN (decl))
1749     {
1750       /* Not marked GTY; it doesn't need to be GC'd or written to PCH.  */
1751       static hash_set<tree> *explained;
1752
1753       special_function_kind sfk;
1754       location_t loc;
1755       bool informed;
1756       tree ctype;
1757
1758       if (!explained)
1759         explained = new hash_set<tree>;
1760       if (explained->add (decl))
1761         return true;
1762
1763       sfk = special_function_p (decl);
1764       ctype = DECL_CONTEXT (decl);
1765       loc = input_location;
1766       input_location = DECL_SOURCE_LOCATION (decl);
1767
1768       informed = false;
1769       if (LAMBDA_TYPE_P (ctype))
1770         {
1771           informed = true;
1772           if (sfk == sfk_constructor)
1773             inform (DECL_SOURCE_LOCATION (decl),
1774                     "a lambda closure type has a deleted default constructor");
1775           else if (sfk == sfk_copy_assignment)
1776             inform (DECL_SOURCE_LOCATION (decl),
1777                     "a lambda closure type has a deleted copy assignment operator");
1778           else
1779             informed = false;
1780         }
1781       else if (DECL_ARTIFICIAL (decl)
1782                && (sfk == sfk_copy_assignment
1783                    || sfk == sfk_copy_constructor)
1784                && (type_has_user_declared_move_constructor (ctype)
1785                    || type_has_user_declared_move_assign (ctype)))
1786         {
1787           inform (DECL_SOURCE_LOCATION (decl),
1788                   "%q#D is implicitly declared as deleted because %qT "
1789                   "declares a move constructor or move assignment operator",
1790                   decl, ctype);
1791           informed = true;
1792         }
1793       else if (sfk == sfk_inheriting_constructor)
1794         {
1795           tree binfo = inherited_ctor_binfo (decl);
1796           if (TREE_CODE (binfo) != TREE_BINFO)
1797             {
1798               inform (DECL_SOURCE_LOCATION (decl),
1799                       "%q#D inherits from multiple base subobjects",
1800                       decl);
1801               informed = true;
1802             }
1803         }
1804       if (!informed)
1805         {
1806           tree parms = FUNCTION_FIRST_USER_PARMTYPE (decl);
1807           tree parm_type = TREE_VALUE (parms);
1808           bool const_p = CP_TYPE_CONST_P (non_reference (parm_type));
1809           tree raises = NULL_TREE;
1810           bool deleted_p = false;
1811           tree scope = push_scope (ctype);
1812
1813           synthesized_method_walk (ctype, sfk, const_p,
1814                                    &raises, NULL, &deleted_p, NULL, false,
1815                                    DECL_INHERITED_CTOR (decl), parms);
1816           if (deleted_p)
1817             {
1818               inform (DECL_SOURCE_LOCATION (decl),
1819                       "%q#D is implicitly deleted because the default "
1820                       "definition would be ill-formed:", decl);
1821               synthesized_method_walk (ctype, sfk, const_p,
1822                                        NULL, NULL, NULL, NULL, true,
1823                                        DECL_INHERITED_CTOR (decl), parms);
1824             }
1825           else if (!comp_except_specs
1826                    (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (decl)),
1827                     raises, ce_normal))
1828             inform (DECL_SOURCE_LOCATION (decl), "%q#F is implicitly "
1829                     "deleted because its exception-specification does not "
1830                     "match the implicit exception-specification %qX",
1831                     decl, raises);
1832           else if (flag_checking)
1833             gcc_unreachable ();
1834
1835           pop_scope (scope);
1836         }
1837
1838       input_location = loc;
1839       return true;
1840     }
1841   return false;
1842 }
1843
1844 /* DECL is a defaulted function which was declared constexpr.  Explain why
1845    it can't be constexpr.  */
1846
1847 void
1848 explain_implicit_non_constexpr (tree decl)
1849 {
1850   tree parm_type = TREE_VALUE (FUNCTION_FIRST_USER_PARMTYPE (decl));
1851   bool const_p = CP_TYPE_CONST_P (non_reference (parm_type));
1852   bool dummy;
1853   synthesized_method_walk (DECL_CLASS_CONTEXT (decl),
1854                            special_function_p (decl), const_p,
1855                            NULL, NULL, NULL, &dummy, true,
1856                            DECL_INHERITED_CTOR (decl),
1857                            FUNCTION_FIRST_USER_PARMTYPE (decl));
1858 }
1859
1860 /* DECL is an instantiation of an inheriting constructor template.  Deduce
1861    the correct exception-specification and deletedness for this particular
1862    specialization.  */
1863
1864 void
1865 deduce_inheriting_ctor (tree decl)
1866 {
1867   decl = DECL_ORIGIN (decl);
1868   gcc_assert (DECL_INHERITED_CTOR (decl));
1869   tree spec;
1870   bool trivial, constexpr_, deleted;
1871   synthesized_method_walk (DECL_CONTEXT (decl), sfk_inheriting_constructor,
1872                            false, &spec, &trivial, &deleted, &constexpr_,
1873                            /*diag*/false,
1874                            DECL_INHERITED_CTOR (decl),
1875                            FUNCTION_FIRST_USER_PARMTYPE (decl));
1876   if (TREE_CODE (inherited_ctor_binfo (decl)) != TREE_BINFO)
1877     /* Inherited the same constructor from different base subobjects.  */
1878     deleted = true;
1879   DECL_DELETED_FN (decl) = deleted;
1880   TREE_TYPE (decl) = build_exception_variant (TREE_TYPE (decl), spec);
1881
1882   tree clone;
1883   FOR_EACH_CLONE (clone, decl)
1884     {
1885       DECL_DELETED_FN (clone) = deleted;
1886       TREE_TYPE (clone) = build_exception_variant (TREE_TYPE (clone), spec);
1887     }
1888 }
1889
1890 /* Implicitly declare the special function indicated by KIND, as a
1891    member of TYPE.  For copy constructors and assignment operators,
1892    CONST_P indicates whether these functions should take a const
1893    reference argument or a non-const reference.  Returns the
1894    FUNCTION_DECL for the implicitly declared function.  */
1895
1896 tree
1897 implicitly_declare_fn (special_function_kind kind, tree type,
1898                        bool const_p, tree inherited_ctor,
1899                        tree inherited_parms)
1900 {
1901   tree fn;
1902   tree parameter_types = void_list_node;
1903   tree return_type;
1904   tree fn_type;
1905   tree raises = empty_except_spec;
1906   tree rhs_parm_type = NULL_TREE;
1907   tree this_parm;
1908   tree name;
1909   HOST_WIDE_INT saved_processing_template_decl;
1910   bool deleted_p;
1911   bool constexpr_p;
1912
1913   /* Because we create declarations for implicitly declared functions
1914      lazily, we may be creating the declaration for a member of TYPE
1915      while in some completely different context.  However, TYPE will
1916      never be a dependent class (because we never want to do lookups
1917      for implicitly defined functions in a dependent class).
1918      Furthermore, we must set PROCESSING_TEMPLATE_DECL to zero here
1919      because we only create clones for constructors and destructors
1920      when not in a template.  */
1921   gcc_assert (!dependent_type_p (type));
1922   saved_processing_template_decl = processing_template_decl;
1923   processing_template_decl = 0;
1924
1925   type = TYPE_MAIN_VARIANT (type);
1926
1927   if (targetm.cxx.cdtor_returns_this ())
1928     {
1929       if (kind == sfk_destructor)
1930         /* See comment in check_special_function_return_type.  */
1931         return_type = build_pointer_type (void_type_node);
1932       else
1933         return_type = build_pointer_type (type);
1934     }
1935   else
1936     return_type = void_type_node;
1937
1938   switch (kind)
1939     {
1940     case sfk_destructor:
1941       /* Destructor.  */
1942       name = constructor_name (type);
1943       break;
1944
1945     case sfk_constructor:
1946       /* Default constructor.  */
1947       name = constructor_name (type);
1948       break;
1949
1950     case sfk_copy_constructor:
1951     case sfk_copy_assignment:
1952     case sfk_move_constructor:
1953     case sfk_move_assignment:
1954     case sfk_inheriting_constructor:
1955     {
1956       bool move_p;
1957       if (kind == sfk_copy_assignment
1958           || kind == sfk_move_assignment)
1959         {
1960           return_type = build_reference_type (type);
1961           name = cp_assignment_operator_id (NOP_EXPR);
1962         }
1963       else
1964         name = constructor_name (type);
1965
1966       if (kind == sfk_inheriting_constructor)
1967         parameter_types = inherited_parms;
1968       else
1969         {
1970           if (const_p)
1971             rhs_parm_type = cp_build_qualified_type (type, TYPE_QUAL_CONST);
1972           else
1973             rhs_parm_type = type;
1974           move_p = (kind == sfk_move_assignment
1975                     || kind == sfk_move_constructor);
1976           rhs_parm_type = cp_build_reference_type (rhs_parm_type, move_p);
1977
1978           parameter_types = tree_cons (NULL_TREE, rhs_parm_type, parameter_types);
1979         }
1980       break;
1981     }
1982     default:
1983       gcc_unreachable ();
1984     }
1985
1986   bool trivial_p = false;
1987
1988   if (inherited_ctor)
1989     {
1990       /* For an inheriting constructor, just copy these flags from the
1991          inherited constructor until deduce_inheriting_ctor.  */
1992       raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (inherited_ctor));
1993       deleted_p = DECL_DELETED_FN (inherited_ctor);
1994       constexpr_p = DECL_DECLARED_CONSTEXPR_P (inherited_ctor);
1995     }
1996   else if (cxx_dialect >= cxx11)
1997     {
1998       raises = unevaluated_noexcept_spec ();
1999       synthesized_method_walk (type, kind, const_p, NULL, &trivial_p,
2000                                &deleted_p, &constexpr_p, false,
2001                                inherited_ctor, inherited_parms);
2002     }
2003   else
2004     synthesized_method_walk (type, kind, const_p, &raises, &trivial_p,
2005                              &deleted_p, &constexpr_p, false,
2006                              inherited_ctor, inherited_parms);
2007   /* Don't bother marking a deleted constructor as constexpr.  */
2008   if (deleted_p)
2009     constexpr_p = false;
2010   /* A trivial copy/move constructor is also a constexpr constructor,
2011      unless the class has virtual bases (7.1.5p4).  */
2012   else if (trivial_p && cxx_dialect >= cxx11
2013            && (kind == sfk_copy_constructor
2014                || kind == sfk_move_constructor)
2015            && !CLASSTYPE_VBASECLASSES (type))
2016     gcc_assert (constexpr_p);
2017
2018   if (!trivial_p && type_has_trivial_fn (type, kind))
2019     type_set_nontrivial_flag (type, kind);
2020
2021   /* Create the function.  */
2022   fn_type = build_method_type_directly (type, return_type, parameter_types);
2023   if (raises)
2024     fn_type = build_exception_variant (fn_type, raises);
2025   fn = build_lang_decl (FUNCTION_DECL, name, fn_type);
2026   if (kind != sfk_inheriting_constructor)
2027     DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (TYPE_NAME (type));
2028   if (kind == sfk_constructor || kind == sfk_copy_constructor
2029       || kind == sfk_move_constructor || kind == sfk_inheriting_constructor)
2030     DECL_CONSTRUCTOR_P (fn) = 1;
2031   else if (kind == sfk_destructor)
2032     DECL_DESTRUCTOR_P (fn) = 1;
2033   else
2034     {
2035       DECL_ASSIGNMENT_OPERATOR_P (fn) = 1;
2036       SET_OVERLOADED_OPERATOR_CODE (fn, NOP_EXPR);
2037     }
2038
2039   SET_DECL_ALIGN (fn, MINIMUM_METHOD_BOUNDARY);
2040
2041   /* Create the explicit arguments.  */
2042   if (rhs_parm_type)
2043     {
2044       /* Note that this parameter is *not* marked DECL_ARTIFICIAL; we
2045          want its type to be included in the mangled function
2046          name.  */
2047       tree decl = cp_build_parm_decl (NULL_TREE, rhs_parm_type);
2048       TREE_READONLY (decl) = 1;
2049       retrofit_lang_decl (decl);
2050       DECL_PARM_INDEX (decl) = DECL_PARM_LEVEL (decl) = 1;
2051       DECL_ARGUMENTS (fn) = decl;
2052     }
2053   else if (kind == sfk_inheriting_constructor)
2054     {
2055       tree *p = &DECL_ARGUMENTS (fn);
2056       int index = 1;
2057       for (tree parm = inherited_parms; parm && parm != void_list_node;
2058            parm = TREE_CHAIN (parm))
2059         {
2060           *p = cp_build_parm_decl (NULL_TREE, TREE_VALUE (parm));
2061           retrofit_lang_decl (*p);
2062           DECL_PARM_LEVEL (*p) = 1;
2063           DECL_PARM_INDEX (*p) = index++;
2064           DECL_CONTEXT (*p) = fn;
2065           p = &DECL_CHAIN (*p);
2066         }
2067       SET_DECL_INHERITED_CTOR (fn, inherited_ctor);
2068       DECL_NONCONVERTING_P (fn) = DECL_NONCONVERTING_P (inherited_ctor);
2069       /* A constructor so declared has the same access as the corresponding
2070          constructor in X.  */
2071       TREE_PRIVATE (fn) = TREE_PRIVATE (inherited_ctor);
2072       TREE_PROTECTED (fn) = TREE_PROTECTED (inherited_ctor);
2073       /* Copy constexpr from the inherited constructor even if the
2074          inheriting constructor doesn't satisfy the requirements.  */
2075       constexpr_p = DECL_DECLARED_CONSTEXPR_P (inherited_ctor);
2076     }
2077   /* Add the "this" parameter.  */
2078   this_parm = build_this_parm (fn_type, TYPE_UNQUALIFIED);
2079   DECL_CHAIN (this_parm) = DECL_ARGUMENTS (fn);
2080   DECL_ARGUMENTS (fn) = this_parm;
2081
2082   grokclassfn (type, fn, kind == sfk_destructor ? DTOR_FLAG : NO_SPECIAL);
2083   DECL_IN_AGGR_P (fn) = 1;
2084   DECL_ARTIFICIAL (fn) = 1;
2085   DECL_DEFAULTED_FN (fn) = 1;
2086   if (cxx_dialect >= cxx11)
2087     {
2088       DECL_DELETED_FN (fn) = deleted_p;
2089       DECL_DECLARED_CONSTEXPR_P (fn) = constexpr_p;
2090     }
2091   DECL_EXTERNAL (fn) = true;
2092   DECL_NOT_REALLY_EXTERN (fn) = 1;
2093   DECL_DECLARED_INLINE_P (fn) = 1;
2094   set_linkage_according_to_type (type, fn);
2095   if (TREE_PUBLIC (fn))
2096     DECL_COMDAT (fn) = 1;
2097   rest_of_decl_compilation (fn, toplevel_bindings_p (), at_eof);
2098   gcc_assert (!TREE_USED (fn));
2099
2100   /* Propagate constraints from the inherited constructor. */
2101   if (flag_concepts && inherited_ctor)
2102     if (tree orig_ci = get_constraints (inherited_ctor))
2103       {
2104         tree new_ci = copy_node (orig_ci);
2105         set_constraints (fn, new_ci);
2106       }
2107
2108   /* Restore PROCESSING_TEMPLATE_DECL.  */
2109   processing_template_decl = saved_processing_template_decl;
2110
2111   if (inherited_ctor && TREE_CODE (inherited_ctor) == TEMPLATE_DECL)
2112     fn = add_inherited_template_parms (fn, inherited_ctor);
2113
2114   /* Warn about calling a non-trivial move assignment in a virtual base.  */
2115   if (kind == sfk_move_assignment && !deleted_p && !trivial_p
2116       && CLASSTYPE_VBASECLASSES (type))
2117     {
2118       location_t loc = input_location;
2119       input_location = DECL_SOURCE_LOCATION (fn);
2120       synthesized_method_walk (type, kind, const_p,
2121                                NULL, NULL, NULL, NULL, true,
2122                                NULL_TREE, NULL_TREE);
2123       input_location = loc;
2124     }
2125
2126   return fn;
2127 }
2128
2129 /* Gives any errors about defaulted functions which need to be deferred
2130    until the containing class is complete.  */
2131
2132 void
2133 defaulted_late_check (tree fn)
2134 {
2135   /* Complain about invalid signature for defaulted fn.  */
2136   tree ctx = DECL_CONTEXT (fn);
2137   special_function_kind kind = special_function_p (fn);
2138   bool fn_const_p = (copy_fn_p (fn) == 2);
2139   tree implicit_fn = implicitly_declare_fn (kind, ctx, fn_const_p,
2140                                             NULL, NULL);
2141   tree eh_spec = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (implicit_fn));
2142
2143   if (!same_type_p (TREE_TYPE (TREE_TYPE (fn)),
2144                     TREE_TYPE (TREE_TYPE (implicit_fn)))
2145       || !compparms (TYPE_ARG_TYPES (TREE_TYPE (fn)),
2146                      TYPE_ARG_TYPES (TREE_TYPE (implicit_fn))))
2147     {
2148       error ("defaulted declaration %q+D", fn);
2149       error_at (DECL_SOURCE_LOCATION (fn),
2150                 "does not match expected signature %qD", implicit_fn);
2151     }
2152
2153   /* 8.4.2/2: An explicitly-defaulted function (...) may have an explicit
2154      exception-specification only if it is compatible (15.4) with the
2155      exception-specification on the implicit declaration.  If a function
2156      is explicitly defaulted on its first declaration, (...) it is
2157      implicitly considered to have the same exception-specification as if
2158      it had been implicitly declared.  */
2159   maybe_instantiate_noexcept (fn);
2160   tree fn_spec = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn));
2161   if (!fn_spec)
2162     {
2163       if (DECL_DEFAULTED_IN_CLASS_P (fn))
2164         TREE_TYPE (fn) = build_exception_variant (TREE_TYPE (fn), eh_spec);
2165     }
2166   else if (UNEVALUATED_NOEXCEPT_SPEC_P (fn_spec))
2167     /* Equivalent to the implicit spec.  */;
2168   else if (DECL_DEFAULTED_IN_CLASS_P (fn)
2169            && !CLASSTYPE_TEMPLATE_INSTANTIATION (ctx))
2170     /* We can't compare an explicit exception-specification on a
2171        constructor defaulted in the class body to the implicit
2172        exception-specification until after we've parsed any NSDMI; see
2173        after_nsdmi_defaulted_late_checks.  */;
2174   else
2175     {
2176       tree eh_spec = get_defaulted_eh_spec (fn);
2177       if (!comp_except_specs (fn_spec, eh_spec, ce_normal))
2178         {
2179           if (DECL_DEFAULTED_IN_CLASS_P (fn))
2180             DECL_DELETED_FN (fn) = true;
2181           else
2182             error ("function %q+D defaulted on its redeclaration "
2183                    "with an exception-specification that differs from "
2184                    "the implicit exception-specification %qX", fn, eh_spec);
2185         }
2186     }
2187
2188   if (DECL_DEFAULTED_IN_CLASS_P (fn)
2189       && DECL_DECLARED_CONSTEXPR_P (implicit_fn))
2190     {
2191       /* Hmm...should we do this for out-of-class too? Should it be OK to
2192          add constexpr later like inline, rather than requiring
2193          declarations to match?  */
2194       DECL_DECLARED_CONSTEXPR_P (fn) = true;
2195       if (kind == sfk_constructor)
2196         TYPE_HAS_CONSTEXPR_CTOR (ctx) = true;
2197     }
2198
2199   if (!DECL_DECLARED_CONSTEXPR_P (implicit_fn)
2200       && DECL_DECLARED_CONSTEXPR_P (fn))
2201     {
2202       if (!CLASSTYPE_TEMPLATE_INSTANTIATION (ctx))
2203         {
2204           error ("explicitly defaulted function %q+D cannot be declared "
2205                  "as constexpr because the implicit declaration is not "
2206                  "constexpr:", fn);
2207           explain_implicit_non_constexpr (fn);
2208         }
2209       DECL_DECLARED_CONSTEXPR_P (fn) = false;
2210     }
2211
2212   if (DECL_DELETED_FN (implicit_fn))
2213     DECL_DELETED_FN (fn) = 1;
2214 }
2215
2216 /* OK, we've parsed the NSDMI for class T, now we can check any explicit
2217    exception-specifications on functions defaulted in the class body.  */
2218
2219 void
2220 after_nsdmi_defaulted_late_checks (tree t)
2221 {
2222   if (uses_template_parms (t))
2223     return;
2224   if (t == error_mark_node)
2225     return;
2226   for (tree fn = TYPE_METHODS (t); fn; fn = DECL_CHAIN (fn))
2227     if (!DECL_ARTIFICIAL (fn) && DECL_DEFAULTED_IN_CLASS_P (fn))
2228       {
2229         tree fn_spec = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn));
2230         if (UNEVALUATED_NOEXCEPT_SPEC_P (fn_spec))
2231           continue;
2232
2233         tree eh_spec = get_defaulted_eh_spec (fn);
2234         if (!comp_except_specs (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)),
2235                                 eh_spec, ce_normal))
2236           DECL_DELETED_FN (fn) = true;
2237       }
2238 }
2239
2240 /* Returns true iff FN can be explicitly defaulted, and gives any
2241    errors if defaulting FN is ill-formed.  */
2242
2243 bool
2244 defaultable_fn_check (tree fn)
2245 {
2246   special_function_kind kind = sfk_none;
2247
2248   if (template_parm_scope_p ())
2249     {
2250       error ("a template cannot be defaulted");
2251       return false;
2252     }
2253
2254   if (DECL_CONSTRUCTOR_P (fn))
2255     {
2256       if (FUNCTION_FIRST_USER_PARMTYPE (fn) == void_list_node)
2257         kind = sfk_constructor;
2258       else if (copy_fn_p (fn) > 0
2259                && (TREE_CHAIN (FUNCTION_FIRST_USER_PARMTYPE (fn))
2260                    == void_list_node))
2261         kind = sfk_copy_constructor;
2262       else if (move_fn_p (fn))
2263         kind = sfk_move_constructor;
2264     }
2265   else if (DECL_DESTRUCTOR_P (fn))
2266     kind = sfk_destructor;
2267   else if (DECL_ASSIGNMENT_OPERATOR_P (fn)
2268            && DECL_OVERLOADED_OPERATOR_P (fn) == NOP_EXPR)
2269     {
2270       if (copy_fn_p (fn))
2271         kind = sfk_copy_assignment;
2272       else if (move_fn_p (fn))
2273         kind = sfk_move_assignment;
2274     }
2275
2276   if (kind == sfk_none)
2277     {
2278       error ("%qD cannot be defaulted", fn);
2279       return false;
2280     }
2281   else
2282     {
2283       for (tree t = FUNCTION_FIRST_USER_PARMTYPE (fn);
2284            t && t != void_list_node; t = TREE_CHAIN (t))
2285         if (TREE_PURPOSE (t))
2286           {
2287             error ("defaulted function %q+D with default argument", fn);
2288             break;
2289           }
2290
2291       /* Avoid do_warn_unused_parameter warnings.  */
2292       for (tree p = FUNCTION_FIRST_USER_PARM (fn); p; p = DECL_CHAIN (p))
2293         if (DECL_NAME (p))
2294           TREE_NO_WARNING (p) = 1;
2295
2296       if (TYPE_BEING_DEFINED (DECL_CONTEXT (fn)))
2297         /* Defer checking.  */;
2298       else if (!processing_template_decl)
2299         defaulted_late_check (fn);
2300
2301       return true;
2302     }
2303 }
2304
2305 /* Add an implicit declaration to TYPE for the kind of function
2306    indicated by SFK.  Return the FUNCTION_DECL for the new implicit
2307    declaration.  */
2308
2309 tree
2310 lazily_declare_fn (special_function_kind sfk, tree type)
2311 {
2312   tree fn;
2313   /* Whether or not the argument has a const reference type.  */
2314   bool const_p = false;
2315
2316   type = TYPE_MAIN_VARIANT (type);
2317
2318   switch (sfk)
2319     {
2320     case sfk_constructor:
2321       CLASSTYPE_LAZY_DEFAULT_CTOR (type) = 0;
2322       break;
2323     case sfk_copy_constructor:
2324       const_p = TYPE_HAS_CONST_COPY_CTOR (type);
2325       CLASSTYPE_LAZY_COPY_CTOR (type) = 0;
2326       break;
2327     case sfk_move_constructor:
2328       CLASSTYPE_LAZY_MOVE_CTOR (type) = 0;
2329       break;
2330     case sfk_copy_assignment:
2331       const_p = TYPE_HAS_CONST_COPY_ASSIGN (type);
2332       CLASSTYPE_LAZY_COPY_ASSIGN (type) = 0;
2333       break;
2334     case sfk_move_assignment:
2335       CLASSTYPE_LAZY_MOVE_ASSIGN (type) = 0;
2336       break;
2337     case sfk_destructor:
2338       CLASSTYPE_LAZY_DESTRUCTOR (type) = 0;
2339       break;
2340     default:
2341       gcc_unreachable ();
2342     }
2343
2344   /* Declare the function.  */
2345   fn = implicitly_declare_fn (sfk, type, const_p, NULL, NULL);
2346
2347   /* [class.copy]/8 If the class definition declares a move constructor or
2348      move assignment operator, the implicitly declared copy constructor is
2349      defined as deleted.... */
2350   if ((sfk == sfk_copy_assignment
2351        || sfk == sfk_copy_constructor)
2352       && (type_has_user_declared_move_constructor (type)
2353           || type_has_user_declared_move_assign (type)))
2354     DECL_DELETED_FN (fn) = true;
2355
2356   /* A destructor may be virtual.  */
2357   if (sfk == sfk_destructor
2358       || sfk == sfk_move_assignment
2359       || sfk == sfk_copy_assignment)
2360     check_for_override (fn, type);
2361   /* Add it to CLASSTYPE_METHOD_VEC.  */
2362   add_method (type, fn, NULL_TREE);
2363   /* Add it to TYPE_METHODS.  */
2364   if (sfk == sfk_destructor
2365       && DECL_VIRTUAL_P (fn))
2366     /* The ABI requires that a virtual destructor go at the end of the
2367        vtable.  */
2368     TYPE_METHODS (type) = chainon (TYPE_METHODS (type), fn);
2369   else
2370     {
2371       DECL_CHAIN (fn) = TYPE_METHODS (type);
2372       TYPE_METHODS (type) = fn;
2373     }
2374   maybe_add_class_template_decl_list (type, fn, /*friend_p=*/0);
2375   if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn)
2376       || DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn))
2377     /* Create appropriate clones.  */
2378     clone_function_decl (fn, /*update_method_vec=*/true);
2379
2380   return fn;
2381 }
2382
2383 /* Given a FUNCTION_DECL FN and a chain LIST, skip as many elements of LIST
2384    as there are artificial parms in FN.  */
2385
2386 tree
2387 skip_artificial_parms_for (const_tree fn, tree list)
2388 {
2389   if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn))
2390     list = TREE_CHAIN (list);
2391   else
2392     return list;
2393
2394   if (DECL_HAS_IN_CHARGE_PARM_P (fn))
2395     list = TREE_CHAIN (list);
2396   if (DECL_HAS_VTT_PARM_P (fn))
2397     list = TREE_CHAIN (list);
2398   return list;
2399 }
2400
2401 /* Given a FUNCTION_DECL FN and a chain LIST, return the number of
2402    artificial parms in FN.  */
2403
2404 int
2405 num_artificial_parms_for (const_tree fn)
2406 {
2407   int count = 0;
2408
2409   if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn))
2410     count++;
2411   else
2412     return 0;
2413
2414   if (DECL_HAS_IN_CHARGE_PARM_P (fn))
2415     count++;
2416   if (DECL_HAS_VTT_PARM_P (fn))
2417     count++;
2418   return count;
2419 }
2420
2421
2422 #include "gt-cp-method.h"