gcc/cp/decl2.c

   1 /* Process declarations and variables for C++ compiler.
   2    Copyright (C) 1988-2021 Free Software Foundation, Inc.
   3    Hacked by Michael Tiemann (tiemann@cygnus.com)
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21
  22 /* Process declarations and symbol lookup for C++ front end.
  23    Also constructs types; the standard scalar types at initialization,
  24    and structure, union, array and enum types when they are declared.  */
  25
  26 /* ??? not all decl nodes are given the most useful possible
  27    line numbers.  For example, the CONST_DECLs for enum values.  */
  28
  29 #include "config.h"
  30 #include "system.h"
  31 #include "coretypes.h"
  32 #include "memmodel.h"
  33 #include "target.h"
  34 #include "cp-tree.h"
  35 #include "c-family/c-common.h"
  36 #include "timevar.h"
  37 #include "stringpool.h"
  38 #include "cgraph.h"
  39 #include "varasm.h"
  40 #include "attribs.h"
  41 #include "stor-layout.h"
  42 #include "calls.h"
  43 #include "decl.h"
  44 #include "toplev.h"
  45 #include "c-family/c-objc.h"
  46 #include "c-family/c-pragma.h"
  47 #include "dumpfile.h"
  48 #include "intl.h"
  49 #include "c-family/c-ada-spec.h"
  50 #include "asan.h"
  51 #include "optabs-query.h"
  52
  53 /* Id for dumping the raw trees.  */
  54 int raw_dump_id;
  55
  56 extern cpp_reader *parse_in;
  57
  58 /* This structure contains information about the initializations
  59    and/or destructions required for a particular priority level.  */
  60 typedef struct priority_info_s {
  61   /* Nonzero if there have been any initializations at this priority
  62      throughout the translation unit.  */
  63   int initializations_p;
  64   /* Nonzero if there have been any destructions at this priority
  65      throughout the translation unit.  */
  66   int destructions_p;
  67 } *priority_info;
  68
  69 static tree start_objects (int, int);
  70 static void finish_objects (int, int, tree);
  71 static tree start_static_storage_duration_function (unsigned);
  72 static void finish_static_storage_duration_function (tree);
  73 static priority_info get_priority_info (int);
  74 static void do_static_initialization_or_destruction (tree, bool);
  75 static void one_static_initialization_or_destruction (tree, tree, bool);
  76 static void generate_ctor_or_dtor_function (bool, int, location_t *);
  77 static int generate_ctor_and_dtor_functions_for_priority (splay_tree_node,
  78                                                           void *);
  79 static tree prune_vars_needing_no_initialization (tree *);
  80 static void write_out_vars (tree);
  81 static void import_export_class (tree);
  82 static tree get_guard_bits (tree);
  83 static void determine_visibility_from_class (tree, tree);
  84 static bool determine_hidden_inline (tree);
  85
  86 /* A list of static class variables.  This is needed, because a
  87    static class variable can be declared inside the class without
  88    an initializer, and then initialized, statically, outside the class.  */
  89 static GTY(()) vec<tree, va_gc> *pending_statics;
  90
  91 /* A list of functions which were declared inline, but which we
  92    may need to emit outline anyway.  */
  93 static GTY(()) vec<tree, va_gc> *deferred_fns;
  94
  95 /* A list of decls that use types with no linkage, which we need to make
  96    sure are defined.  */
  97 static GTY(()) vec<tree, va_gc> *no_linkage_decls;
  98
  99 /* A vector of alternating decls and identifiers, where the latter
 100    is to be an alias for the former if the former is defined.  */
 101 static GTY(()) vec<tree, va_gc> *mangling_aliases;
 102
 103 /* hash traits for declarations.  Hashes single decls via
 104    DECL_ASSEMBLER_NAME_RAW.  */
 105
 106 struct mangled_decl_hash : ggc_remove <tree>
 107 {
 108   typedef tree value_type; /* A DECL.  */
 109   typedef tree compare_type; /* An identifier.  */
 110
 111   static hashval_t hash (const value_type decl)
 112   {
 113     return IDENTIFIER_HASH_VALUE (DECL_ASSEMBLER_NAME_RAW (decl));
 114   }
 115   static bool equal (const value_type existing, compare_type candidate)
 116   {
 117     tree name = DECL_ASSEMBLER_NAME_RAW (existing);
 118     return candidate == name;
 119   }
 120
 121   static const bool empty_zero_p = true;
 122   static inline void mark_empty (value_type &p) {p = NULL_TREE;}
 123   static inline bool is_empty (value_type p) {return !p;}
 124
 125   static bool is_deleted (value_type e)
 126   {
 127     return e == reinterpret_cast <value_type> (1);
 128   }
 129   static void mark_deleted (value_type &e)
 130   {
 131     e = reinterpret_cast <value_type> (1);
 132   }
 133 };
 134
 135 /* A hash table of decls keyed by mangled name.  Used to figure out if
 136    we need compatibility aliases.  */
 137 static GTY(()) hash_table<mangled_decl_hash> *mangled_decls;
 138
 139 /* Nonzero if we're done parsing and into end-of-file activities.  */
 140
 141 int at_eof;
 142
 143 /* True if note_mangling_alias should enqueue mangling aliases for
 144    later generation, rather than emitting them right away.  */
 145
 146 bool defer_mangling_aliases = true;
 147 \f
 148
 149 /* Return a member function type (a METHOD_TYPE), given FNTYPE (a
 150    FUNCTION_TYPE), CTYPE (class type), and QUALS (the cv-qualifiers
 151    that apply to the function).  */
 152
 153 tree
 154 build_memfn_type (tree fntype, tree ctype, cp_cv_quals quals,
 155                   cp_ref_qualifier rqual)
 156 {
 157   if (fntype == error_mark_node || ctype == error_mark_node)
 158     return error_mark_node;
 159
 160   gcc_assert (FUNC_OR_METHOD_TYPE_P (fntype));
 161
 162   cp_cv_quals type_quals = quals & ~TYPE_QUAL_RESTRICT;
 163   ctype = cp_build_qualified_type (ctype, type_quals);
 164
 165   tree newtype
 166     = build_method_type_directly (ctype, TREE_TYPE (fntype),
 167                                   (TREE_CODE (fntype) == METHOD_TYPE
 168                                    ? TREE_CHAIN (TYPE_ARG_TYPES (fntype))
 169                                    : TYPE_ARG_TYPES (fntype)));
 170   if (tree attrs = TYPE_ATTRIBUTES (fntype))
 171     newtype = cp_build_type_attribute_variant (newtype, attrs);
 172   newtype = build_cp_fntype_variant (newtype, rqual,
 173                                      TYPE_RAISES_EXCEPTIONS (fntype),
 174                                      TYPE_HAS_LATE_RETURN_TYPE (fntype));
 175
 176   return newtype;
 177 }
 178
 179 /* Return a variant of FNTYPE, a FUNCTION_TYPE or METHOD_TYPE, with its
 180    return type changed to NEW_RET.  */
 181
 182 tree
 183 change_return_type (tree new_ret, tree fntype)
 184 {
 185   if (new_ret == error_mark_node)
 186     return fntype;
 187
 188   if (same_type_p (new_ret, TREE_TYPE (fntype)))
 189     return fntype;
 190
 191   tree newtype;
 192   tree args = TYPE_ARG_TYPES (fntype);
 193
 194   if (TREE_CODE (fntype) == FUNCTION_TYPE)
 195     {
 196       newtype = build_function_type (new_ret, args);
 197       newtype = apply_memfn_quals (newtype,
 198                                    type_memfn_quals (fntype));
 199     }
 200   else
 201     newtype = build_method_type_directly
 202       (class_of_this_parm (fntype), new_ret, TREE_CHAIN (args));
 203
 204   if (tree attrs = TYPE_ATTRIBUTES (fntype))
 205     newtype = cp_build_type_attribute_variant (newtype, attrs);
 206   newtype = cxx_copy_lang_qualifiers (newtype, fntype);
 207
 208   return newtype;
 209 }
 210
 211 /* Build a PARM_DECL of FN with NAME and TYPE, and set DECL_ARG_TYPE
 212    appropriately.  */
 213
 214 tree
 215 cp_build_parm_decl (tree fn, tree name, tree type)
 216 {
 217   tree parm = build_decl (input_location,
 218                           PARM_DECL, name, type);
 219   DECL_CONTEXT (parm) = fn;
 220
 221   /* DECL_ARG_TYPE is only used by the back end and the back end never
 222      sees templates.  */
 223   if (!processing_template_decl)
 224     DECL_ARG_TYPE (parm) = type_passed_as (type);
 225
 226   return parm;
 227 }
 228
 229 /* Returns a PARM_DECL of FN for a parameter of the indicated TYPE, with the
 230    indicated NAME.  */
 231
 232 tree
 233 build_artificial_parm (tree fn, tree name, tree type)
 234 {
 235   tree parm = cp_build_parm_decl (fn, name, type);
 236   DECL_ARTIFICIAL (parm) = 1;
 237   /* All our artificial parms are implicitly `const'; they cannot be
 238      assigned to.  */
 239   TREE_READONLY (parm) = 1;
 240   return parm;
 241 }
 242
 243 /* Constructors for types with virtual baseclasses need an "in-charge" flag
 244    saying whether this constructor is responsible for initialization of
 245    virtual baseclasses or not.  All destructors also need this "in-charge"
 246    flag, which additionally determines whether or not the destructor should
 247    free the memory for the object.
 248
 249    This function adds the "in-charge" flag to member function FN if
 250    appropriate.  It is called from grokclassfn and tsubst.
 251    FN must be either a constructor or destructor.
 252
 253    The in-charge flag follows the 'this' parameter, and is followed by the
 254    VTT parm (if any), then the user-written parms.  */
 255
 256 void
 257 maybe_retrofit_in_chrg (tree fn)
 258 {
 259   tree basetype, arg_types, parms, parm, fntype;
 260
 261   /* If we've already add the in-charge parameter don't do it again.  */
 262   if (DECL_HAS_IN_CHARGE_PARM_P (fn))
 263     return;
 264
 265   /* When processing templates we can't know, in general, whether or
 266      not we're going to have virtual baseclasses.  */
 267   if (processing_template_decl)
 268     return;
 269
 270   /* We don't need an in-charge parameter for constructors that don't
 271      have virtual bases.  */
 272   if (DECL_CONSTRUCTOR_P (fn)
 273       && !CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fn)))
 274     return;
 275
 276   arg_types = TYPE_ARG_TYPES (TREE_TYPE (fn));
 277   basetype = TREE_TYPE (TREE_VALUE (arg_types));
 278   arg_types = TREE_CHAIN (arg_types);
 279
 280   parms = DECL_CHAIN (DECL_ARGUMENTS (fn));
 281
 282   /* If this is a subobject constructor or destructor, our caller will
 283      pass us a pointer to our VTT.  */
 284   if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fn)))
 285     {
 286       parm = build_artificial_parm (fn, vtt_parm_identifier, vtt_parm_type);
 287
 288       /* First add it to DECL_ARGUMENTS between 'this' and the real args...  */
 289       DECL_CHAIN (parm) = parms;
 290       parms = parm;
 291
 292       /* ...and then to TYPE_ARG_TYPES.  */
 293       arg_types = hash_tree_chain (vtt_parm_type, arg_types);
 294
 295       DECL_HAS_VTT_PARM_P (fn) = 1;
 296     }
 297
 298   /* Then add the in-charge parm (before the VTT parm).  */
 299   parm = build_artificial_parm (fn, in_charge_identifier, integer_type_node);
 300   DECL_CHAIN (parm) = parms;
 301   parms = parm;
 302   arg_types = hash_tree_chain (integer_type_node, arg_types);
 303
 304   /* Insert our new parameter(s) into the list.  */
 305   DECL_CHAIN (DECL_ARGUMENTS (fn)) = parms;
 306
 307   /* And rebuild the function type.  */
 308   fntype = build_method_type_directly (basetype, TREE_TYPE (TREE_TYPE (fn)),
 309                                        arg_types);
 310   if (TYPE_ATTRIBUTES (TREE_TYPE (fn)))
 311     fntype = (cp_build_type_attribute_variant
 312               (fntype, TYPE_ATTRIBUTES (TREE_TYPE (fn))));
 313   fntype = cxx_copy_lang_qualifiers (fntype, TREE_TYPE (fn));
 314   TREE_TYPE (fn) = fntype;
 315
 316   /* Now we've got the in-charge parameter.  */
 317   DECL_HAS_IN_CHARGE_PARM_P (fn) = 1;
 318 }
 319
 320 /* Classes overload their constituent function names automatically.
 321    When a function name is declared in a record structure,
 322    its name is changed to it overloaded name.  Since names for
 323    constructors and destructors can conflict, we place a leading
 324    '$' for destructors.
 325
 326    CNAME is the name of the class we are grokking for.
 327
 328    FUNCTION is a FUNCTION_DECL.  It was created by `grokdeclarator'.
 329
 330    FLAGS contains bits saying what's special about today's
 331    arguments.  DTOR_FLAG == DESTRUCTOR.
 332
 333    If FUNCTION is a destructor, then we must add the `auto-delete' field
 334    as a second parameter.  There is some hair associated with the fact
 335    that we must "declare" this variable in the manner consistent with the
 336    way the rest of the arguments were declared.
 337
 338    QUALS are the qualifiers for the this pointer.  */
 339
 340 void
 341 grokclassfn (tree ctype, tree function, enum overload_flags flags)
 342 {
 343   tree fn_name = DECL_NAME (function);
 344
 345   /* Even within an `extern "C"' block, members get C++ linkage.  See
 346      [dcl.link] for details.  */
 347   SET_DECL_LANGUAGE (function, lang_cplusplus);
 348
 349   if (fn_name == NULL_TREE)
 350     {
 351       error ("name missing for member function");
 352       fn_name = get_identifier ("<anonymous>");
 353       DECL_NAME (function) = fn_name;
 354     }
 355
 356   DECL_CONTEXT (function) = ctype;
 357
 358   if (flags == DTOR_FLAG)
 359     DECL_CXX_DESTRUCTOR_P (function) = 1;
 360
 361   if (flags == DTOR_FLAG || DECL_CONSTRUCTOR_P (function))
 362     maybe_retrofit_in_chrg (function);
 363 }
 364
 365 /* Create an ARRAY_REF, checking for the user doing things backwards
 366    along the way.  DECLTYPE_P is for N3276, as in the parser.  */
 367
 368 tree
 369 grok_array_decl (location_t loc, tree array_expr, tree index_exp,
 370                  bool decltype_p)
 371 {
 372   tree type;
 373   tree expr;
 374   tree orig_array_expr = array_expr;
 375   tree orig_index_exp = index_exp;
 376   tree overload = NULL_TREE;
 377
 378   if (error_operand_p (array_expr) || error_operand_p (index_exp))
 379     return error_mark_node;
 380
 381   if (processing_template_decl)
 382     {
 383       if (type_dependent_expression_p (array_expr)
 384           || type_dependent_expression_p (index_exp))
 385         return build_min_nt_loc (loc, ARRAY_REF, array_expr, index_exp,
 386                                  NULL_TREE, NULL_TREE);
 387       array_expr = build_non_dependent_expr (array_expr);
 388       index_exp = build_non_dependent_expr (index_exp);
 389     }
 390
 391   type = TREE_TYPE (array_expr);
 392   gcc_assert (type);
 393   type = non_reference (type);
 394
 395   /* If they have an `operator[]', use that.  */
 396   if (MAYBE_CLASS_TYPE_P (type) || MAYBE_CLASS_TYPE_P (TREE_TYPE (index_exp)))
 397     {
 398       tsubst_flags_t complain = tf_warning_or_error;
 399       if (decltype_p)
 400         complain |= tf_decltype;
 401       expr = build_new_op (loc, ARRAY_REF, LOOKUP_NORMAL, array_expr,
 402                            index_exp, NULL_TREE, &overload, complain);
 403     }
 404   else
 405     {
 406       tree p1, p2, i1, i2;
 407       bool swapped = false;
 408
 409       /* Otherwise, create an ARRAY_REF for a pointer or array type.
 410          It is a little-known fact that, if `a' is an array and `i' is
 411          an int, you can write `i[a]', which means the same thing as
 412          `a[i]'.  */
 413       if (TREE_CODE (type) == ARRAY_TYPE || VECTOR_TYPE_P (type))
 414         p1 = array_expr;
 415       else
 416         p1 = build_expr_type_conversion (WANT_POINTER, array_expr, false);
 417
 418       if (TREE_CODE (TREE_TYPE (index_exp)) == ARRAY_TYPE)
 419         p2 = index_exp;
 420       else
 421         p2 = build_expr_type_conversion (WANT_POINTER, index_exp, false);
 422
 423       i1 = build_expr_type_conversion (WANT_INT | WANT_ENUM, array_expr,
 424                                        false);
 425       i2 = build_expr_type_conversion (WANT_INT | WANT_ENUM, index_exp,
 426                                        false);
 427
 428       if ((p1 && i2) && (i1 && p2))
 429         error ("ambiguous conversion for array subscript");
 430
 431       if (p1 && i2)
 432         array_expr = p1, index_exp = i2;
 433       else if (i1 && p2)
 434         swapped = true, array_expr = p2, index_exp = i1;
 435       else
 436         {
 437           error_at (loc, "invalid types %<%T[%T]%> for array subscript",
 438                     type, TREE_TYPE (index_exp));
 439           return error_mark_node;
 440         }
 441
 442       if (array_expr == error_mark_node || index_exp == error_mark_node)
 443         error ("ambiguous conversion for array subscript");
 444
 445       if (TYPE_PTR_P (TREE_TYPE (array_expr)))
 446         array_expr = mark_rvalue_use (array_expr);
 447       else
 448         array_expr = mark_lvalue_use_nonread (array_expr);
 449       index_exp = mark_rvalue_use (index_exp);
 450       if (swapped
 451           && flag_strong_eval_order == 2
 452           && (TREE_SIDE_EFFECTS (array_expr) || TREE_SIDE_EFFECTS (index_exp)))
 453         expr = build_array_ref (input_location, index_exp, array_expr);
 454       else
 455         expr = build_array_ref (input_location, array_expr, index_exp);
 456     }
 457   if (processing_template_decl && expr != error_mark_node)
 458     {
 459       if (overload != NULL_TREE)
 460         return (build_min_non_dep_op_overload
 461                 (ARRAY_REF, expr, overload, orig_array_expr, orig_index_exp));
 462
 463       return build_min_non_dep (ARRAY_REF, expr, orig_array_expr, orig_index_exp,
 464                                 NULL_TREE, NULL_TREE);
 465     }
 466   return expr;
 467 }
 468
 469 /* Given the cast expression EXP, checking out its validity.   Either return
 470    an error_mark_node if there was an unavoidable error, return a cast to
 471    void for trying to delete a pointer w/ the value 0, or return the
 472    call to delete.  If DOING_VEC is true, we handle things differently
 473    for doing an array delete.
 474    Implements ARM $5.3.4.  This is called from the parser.  */
 475
 476 tree
 477 delete_sanity (location_t loc, tree exp, tree size, bool doing_vec,
 478                int use_global_delete, tsubst_flags_t complain)
 479 {
 480   tree t, type;
 481
 482   if (exp == error_mark_node)
 483     return exp;
 484
 485   if (processing_template_decl)
 486     {
 487       t = build_min (DELETE_EXPR, void_type_node, exp, size);
 488       DELETE_EXPR_USE_GLOBAL (t) = use_global_delete;
 489       DELETE_EXPR_USE_VEC (t) = doing_vec;
 490       TREE_SIDE_EFFECTS (t) = 1;
 491       SET_EXPR_LOCATION (t, loc);
 492       return t;
 493     }
 494
 495   location_t exp_loc = cp_expr_loc_or_loc (exp, loc);
 496
 497   /* An array can't have been allocated by new, so complain.  */
 498   if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE
 499       && (complain & tf_warning))
 500     warning_at (exp_loc, 0, "deleting array %q#E", exp);
 501
 502   t = build_expr_type_conversion (WANT_POINTER, exp, true);
 503
 504   if (t == NULL_TREE || t == error_mark_node)
 505     {
 506       if (complain & tf_error)
 507         error_at (exp_loc,
 508                   "type %q#T argument given to %<delete%>, expected pointer",
 509                   TREE_TYPE (exp));
 510       return error_mark_node;
 511     }
 512
 513   type = TREE_TYPE (t);
 514
 515   /* As of Valley Forge, you can delete a pointer to const.  */
 516
 517   /* You can't delete functions.  */
 518   if (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
 519     {
 520       if (complain & tf_error)
 521         error_at (exp_loc,
 522                   "cannot delete a function.  Only pointer-to-objects are "
 523                   "valid arguments to %<delete%>");
 524       return error_mark_node;
 525     }
 526
 527   /* Deleting ptr to void is undefined behavior [expr.delete/3].  */
 528   if (VOID_TYPE_P (TREE_TYPE (type)))
 529     {
 530       if (complain & tf_warning)
 531         warning_at (exp_loc, OPT_Wdelete_incomplete,
 532                     "deleting %qT is undefined", type);
 533       doing_vec = 0;
 534     }
 535
 536   /* Deleting a pointer with the value zero is valid and has no effect.  */
 537   if (integer_zerop (t))
 538     return build1_loc (loc, NOP_EXPR, void_type_node, t);
 539
 540   if (doing_vec)
 541     return build_vec_delete (loc, t, /*maxindex=*/NULL_TREE,
 542                              sfk_deleting_destructor,
 543                              use_global_delete, complain);
 544   else
 545     return build_delete (loc, type, t, sfk_deleting_destructor,
 546                          LOOKUP_NORMAL, use_global_delete,
 547                          complain);
 548 }
 549
 550 /* Report an error if the indicated template declaration is not the
 551    sort of thing that should be a member template.  */
 552
 553 void
 554 check_member_template (tree tmpl)
 555 {
 556   tree decl;
 557
 558   gcc_assert (TREE_CODE (tmpl) == TEMPLATE_DECL);
 559   decl = DECL_TEMPLATE_RESULT (tmpl);
 560
 561   if (TREE_CODE (decl) == FUNCTION_DECL
 562       || DECL_ALIAS_TEMPLATE_P (tmpl)
 563       || (TREE_CODE (decl) == TYPE_DECL
 564           && MAYBE_CLASS_TYPE_P (TREE_TYPE (decl))))
 565     {
 566       /* The parser rejects template declarations in local classes
 567          (with the exception of generic lambdas).  */
 568       gcc_assert (!current_function_decl || LAMBDA_FUNCTION_P (decl));
 569       /* The parser rejects any use of virtual in a function template.  */
 570       gcc_assert (!(TREE_CODE (decl) == FUNCTION_DECL
 571                     && DECL_VIRTUAL_P (decl)));
 572
 573       /* The debug-information generating code doesn't know what to do
 574          with member templates.  */
 575       DECL_IGNORED_P (tmpl) = 1;
 576     }
 577   else if (variable_template_p (tmpl))
 578     /* OK */;
 579   else
 580     error ("template declaration of %q#D", decl);
 581 }
 582
 583 /* Sanity check: report error if this function FUNCTION is not
 584    really a member of the class (CTYPE) it is supposed to belong to.
 585    TEMPLATE_PARMS is used to specify the template parameters of a member
 586    template passed as FUNCTION_DECL. If the member template is passed as a
 587    TEMPLATE_DECL, it can be NULL since the parameters can be extracted
 588    from the declaration. If the function is not a function template, it
 589    must be NULL.
 590    It returns the original declaration for the function, NULL_TREE if
 591    no declaration was found, error_mark_node if an error was emitted.  */
 592
 593 tree
 594 check_classfn (tree ctype, tree function, tree template_parms)
 595 {
 596   if (DECL_USE_TEMPLATE (function)
 597       && !(TREE_CODE (function) == TEMPLATE_DECL
 598            && DECL_TEMPLATE_SPECIALIZATION (function))
 599       && DECL_MEMBER_TEMPLATE_P (DECL_TI_TEMPLATE (function)))
 600     /* Since this is a specialization of a member template,
 601        we're not going to find the declaration in the class.
 602        For example, in:
 603
 604          struct S { template <typename T> void f(T); };
 605          template <> void S::f(int);
 606
 607        we're not going to find `S::f(int)', but there's no
 608        reason we should, either.  We let our callers know we didn't
 609        find the method, but we don't complain.  */
 610     return NULL_TREE;
 611
 612   /* Basic sanity check: for a template function, the template parameters
 613      either were not passed, or they are the same of DECL_TEMPLATE_PARMS.  */
 614   if (TREE_CODE (function) == TEMPLATE_DECL)
 615     {
 616       if (template_parms
 617           && !comp_template_parms (template_parms,
 618                                    DECL_TEMPLATE_PARMS (function)))
 619         {
 620           error ("template parameter lists provided don%'t match the "
 621                  "template parameters of %qD", function);
 622           return error_mark_node;
 623         }
 624       template_parms = DECL_TEMPLATE_PARMS (function);
 625     }
 626
 627   /* OK, is this a definition of a member template?  */
 628   bool is_template = (template_parms != NULL_TREE);
 629
 630   /* [temp.mem]
 631
 632      A destructor shall not be a member template.  */
 633   if (DECL_DESTRUCTOR_P (function) && is_template)
 634     {
 635       error ("destructor %qD declared as member template", function);
 636       return error_mark_node;
 637     }
 638
 639   /* We must enter the scope here, because conversion operators are
 640      named by target type, and type equivalence relies on typenames
 641      resolving within the scope of CTYPE.  */
 642   tree pushed_scope = push_scope (ctype);
 643   tree matched = NULL_TREE;
 644   tree fns = get_class_binding (ctype, DECL_NAME (function));
 645
 646   for (ovl_iterator iter (fns); !matched && iter; ++iter)
 647     {
 648       tree fndecl = *iter;
 649
 650       /* A member template definition only matches a member template
 651          declaration.  */
 652       if (is_template != (TREE_CODE (fndecl) == TEMPLATE_DECL))
 653         continue;
 654
 655       if (!DECL_DECLARES_FUNCTION_P (fndecl))
 656         continue;
 657
 658       tree p1 = TYPE_ARG_TYPES (TREE_TYPE (function));
 659       tree p2 = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
 660
 661       /* We cannot simply call decls_match because this doesn't work
 662          for static member functions that are pretending to be
 663          methods, and because the name may have been changed by
 664          asm("new_name").  */
 665
 666       /* Get rid of the this parameter on functions that become
 667          static.  */
 668       if (DECL_STATIC_FUNCTION_P (fndecl)
 669           && TREE_CODE (TREE_TYPE (function)) == METHOD_TYPE)
 670         p1 = TREE_CHAIN (p1);
 671
 672       /* ref-qualifier or absence of same must match.  */
 673       if (type_memfn_rqual (TREE_TYPE (function))
 674           != type_memfn_rqual (TREE_TYPE (fndecl)))
 675         continue;
 676
 677       // Include constraints in the match.
 678       tree c1 = get_constraints (function);
 679       tree c2 = get_constraints (fndecl);
 680
 681       /* While finding a match, same types and params are not enough
 682          if the function is versioned.  Also check version ("target")
 683          attributes.  */
 684       if (same_type_p (TREE_TYPE (TREE_TYPE (function)),
 685                        TREE_TYPE (TREE_TYPE (fndecl)))
 686           && compparms (p1, p2)
 687           && !targetm.target_option.function_versions (function, fndecl)
 688           && (!is_template
 689               || comp_template_parms (template_parms,
 690                                       DECL_TEMPLATE_PARMS (fndecl)))
 691           && equivalent_constraints (c1, c2)
 692           && (DECL_TEMPLATE_SPECIALIZATION (function)
 693               == DECL_TEMPLATE_SPECIALIZATION (fndecl))
 694           && (!DECL_TEMPLATE_SPECIALIZATION (function)
 695               || (DECL_TI_TEMPLATE (function) == DECL_TI_TEMPLATE (fndecl))))
 696         matched = fndecl;
 697     }
 698
 699   if (!matched)
 700     {
 701       if (!COMPLETE_TYPE_P (ctype))
 702         cxx_incomplete_type_error (DECL_SOURCE_LOCATION (function),
 703                                    function, ctype);
 704       else
 705         {
 706           if (DECL_CONV_FN_P (function))
 707             fns = get_class_binding (ctype, conv_op_identifier);
 708
 709           error_at (DECL_SOURCE_LOCATION (function),
 710                     "no declaration matches %q#D", function);
 711           if (fns)
 712             print_candidates (fns);
 713           else if (DECL_CONV_FN_P (function))
 714             inform (DECL_SOURCE_LOCATION (function),
 715                     "no conversion operators declared");
 716           else
 717             inform (DECL_SOURCE_LOCATION (function),
 718                     "no functions named %qD", function);
 719           inform (DECL_SOURCE_LOCATION (TYPE_NAME (ctype)),
 720                   "%#qT defined here", ctype);
 721         }
 722       matched = error_mark_node;
 723     }
 724
 725   if (pushed_scope)
 726     pop_scope (pushed_scope);
 727
 728   return matched;
 729 }
 730
 731 /* DECL is a function with vague linkage.  Remember it so that at the
 732    end of the translation unit we can decide whether or not to emit
 733    it.  */
 734
 735 void
 736 note_vague_linkage_fn (tree decl)
 737 {
 738   if (processing_template_decl)
 739     return;
 740
 741   DECL_DEFER_OUTPUT (decl) = 1;
 742   vec_safe_push (deferred_fns, decl);
 743 }
 744
 745 /* As above, but for variable template instantiations.  */
 746
 747 void
 748 note_variable_template_instantiation (tree decl)
 749 {
 750   vec_safe_push (pending_statics, decl);
 751 }
 752
 753 /* We have just processed the DECL, which is a static data member.
 754    The other parameters are as for cp_finish_decl.  */
 755
 756 void
 757 finish_static_data_member_decl (tree decl,
 758                                 tree init, bool init_const_expr_p,
 759                                 tree asmspec_tree,
 760                                 int flags)
 761 {
 762   if (DECL_TEMPLATE_INSTANTIATED (decl))
 763     /* We already needed to instantiate this, so the processing in this
 764        function is unnecessary/wrong.  */
 765     return;
 766
 767   DECL_CONTEXT (decl) = current_class_type;
 768
 769   /* We cannot call pushdecl here, because that would fill in the
 770      TREE_CHAIN of our decl.  Instead, we modify cp_finish_decl to do
 771      the right thing, namely, to put this decl out straight away.  */
 772
 773   if (! processing_template_decl)
 774     vec_safe_push (pending_statics, decl);
 775
 776   if (LOCAL_CLASS_P (current_class_type)
 777       /* We already complained about the template definition.  */
 778       && !DECL_TEMPLATE_INSTANTIATION (decl))
 779     permerror (DECL_SOURCE_LOCATION (decl),
 780                "local class %q#T shall not have static data member %q#D",
 781                current_class_type, decl);
 782   else
 783     for (tree t = current_class_type; TYPE_P (t);
 784          t = CP_TYPE_CONTEXT (t))
 785       if (TYPE_UNNAMED_P (t))
 786         {
 787           auto_diagnostic_group d;
 788           if (permerror (DECL_SOURCE_LOCATION (decl),
 789                          "static data member %qD in unnamed class", decl))
 790             inform (DECL_SOURCE_LOCATION (TYPE_NAME (t)),
 791                     "unnamed class defined here");
 792           break;
 793         }
 794
 795   if (DECL_INLINE_VAR_P (decl) && !DECL_TEMPLATE_INSTANTIATION (decl))
 796     /* An inline variable is immediately defined, so don't set DECL_IN_AGGR_P.
 797        Except that if decl is a template instantiation, it isn't defined until
 798        instantiate_decl.  */;
 799   else
 800     DECL_IN_AGGR_P (decl) = 1;
 801
 802   if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
 803       && TYPE_DOMAIN (TREE_TYPE (decl)) == NULL_TREE)
 804     SET_VAR_HAD_UNKNOWN_BOUND (decl);
 805
 806   if (init)
 807     {
 808       /* Similarly to start_decl_1, we want to complete the type in order
 809          to do the right thing in cp_apply_type_quals_to_decl, possibly
 810          clear TYPE_QUAL_CONST (c++/65579).  */
 811       tree type = TREE_TYPE (decl) = complete_type (TREE_TYPE (decl));
 812       cp_apply_type_quals_to_decl (cp_type_quals (type), decl);
 813     }
 814
 815   cp_finish_decl (decl, init, init_const_expr_p, asmspec_tree, flags);
 816 }
 817
 818 /* DECLARATOR and DECLSPECS correspond to a class member.  The other
 819    parameters are as for cp_finish_decl.  Return the DECL for the
 820    class member declared.  */
 821
 822 tree
 823 grokfield (const cp_declarator *declarator,
 824            cp_decl_specifier_seq *declspecs,
 825            tree init, bool init_const_expr_p,
 826            tree asmspec_tree,
 827            tree attrlist)
 828 {
 829   tree value;
 830   const char *asmspec = 0;
 831   int flags;
 832
 833   if (init
 834       && TREE_CODE (init) == TREE_LIST
 835       && TREE_VALUE (init) == error_mark_node
 836       && TREE_CHAIN (init) == NULL_TREE)
 837     init = NULL_TREE;
 838
 839   int initialized;
 840   if (init == ridpointers[(int)RID_DELETE])
 841     initialized = SD_DELETED;
 842   else if (init == ridpointers[(int)RID_DEFAULT])
 843     initialized = SD_DEFAULTED;
 844   else if (init)
 845     initialized = SD_INITIALIZED;
 846   else
 847     initialized = SD_UNINITIALIZED;
 848
 849   value = grokdeclarator (declarator, declspecs, FIELD, initialized, &attrlist);
 850   if (! value || value == error_mark_node)
 851     /* friend or constructor went bad.  */
 852     return error_mark_node;
 853   if (TREE_TYPE (value) == error_mark_node)
 854     return value;
 855
 856   if (TREE_CODE (value) == TYPE_DECL && init)
 857     {
 858       error_at (cp_expr_loc_or_loc (init, DECL_SOURCE_LOCATION (value)),
 859                 "typedef %qD is initialized (use %qs instead)",
 860                 value, "decltype");
 861       init = NULL_TREE;
 862     }
 863
 864   /* Pass friendly classes back.  */
 865   if (value == void_type_node)
 866     return value;
 867
 868   if (DECL_NAME (value)
 869       && TREE_CODE (DECL_NAME (value)) == TEMPLATE_ID_EXPR)
 870     {
 871       error_at (declarator->id_loc,
 872                 "explicit template argument list not allowed");
 873       return error_mark_node;
 874     }
 875
 876   /* Stash away type declarations.  */
 877   if (TREE_CODE (value) == TYPE_DECL)
 878     {
 879       DECL_NONLOCAL (value) = 1;
 880       DECL_CONTEXT (value) = current_class_type;
 881
 882       if (attrlist)
 883         {
 884           int attrflags = 0;
 885
 886           /* If this is a typedef that names the class for linkage purposes
 887              (7.1.3p8), apply any attributes directly to the type.  */
 888           if (OVERLOAD_TYPE_P (TREE_TYPE (value))
 889               && value == TYPE_NAME (TYPE_MAIN_VARIANT (TREE_TYPE (value))))
 890             attrflags = ATTR_FLAG_TYPE_IN_PLACE;
 891
 892           cplus_decl_attributes (&value, attrlist, attrflags);
 893         }
 894
 895       if (decl_spec_seq_has_spec_p (declspecs, ds_typedef)
 896           && TREE_TYPE (value) != error_mark_node
 897           && TYPE_NAME (TYPE_MAIN_VARIANT (TREE_TYPE (value))) != value)
 898         set_underlying_type (value);
 899
 900       /* It's important that push_template_decl below follows
 901          set_underlying_type above so that the created template
 902          carries the properly set type of VALUE.  */
 903       if (processing_template_decl)
 904         value = push_template_decl (value);
 905
 906       record_locally_defined_typedef (value);
 907       return value;
 908     }
 909
 910   int friendp = decl_spec_seq_has_spec_p (declspecs, ds_friend);
 911
 912   if (!friendp && DECL_IN_AGGR_P (value))
 913     {
 914       error ("%qD is already defined in %qT", value, DECL_CONTEXT (value));
 915       return void_type_node;
 916     }
 917
 918   if (asmspec_tree && asmspec_tree != error_mark_node)
 919     asmspec = TREE_STRING_POINTER (asmspec_tree);
 920
 921   if (init)
 922     {
 923       if (TREE_CODE (value) == FUNCTION_DECL)
 924         {
 925           if (init == ridpointers[(int)RID_DELETE])
 926             {
 927               DECL_DELETED_FN (value) = 1;
 928               DECL_DECLARED_INLINE_P (value) = 1;
 929             }
 930           else if (init == ridpointers[(int)RID_DEFAULT])
 931             {
 932               if (defaultable_fn_check (value))
 933                 {
 934                   DECL_DEFAULTED_FN (value) = 1;
 935                   DECL_INITIALIZED_IN_CLASS_P (value) = 1;
 936                   DECL_DECLARED_INLINE_P (value) = 1;
 937                   /* grokfndecl set this to error_mark_node, but we want to
 938                      leave it unset until synthesize_method.  */
 939                   DECL_INITIAL (value) = NULL_TREE;
 940                 }
 941             }
 942           else if (TREE_CODE (init) == DEFERRED_PARSE)
 943             error ("invalid initializer for member function %qD", value);
 944           else if (TREE_CODE (TREE_TYPE (value)) == METHOD_TYPE)
 945             {
 946               if (integer_zerop (init))
 947                 DECL_PURE_VIRTUAL_P (value) = 1;
 948               else if (error_operand_p (init))
 949                 ; /* An error has already been reported.  */
 950               else
 951                 error ("invalid initializer for member function %qD",
 952                        value);
 953             }
 954           else
 955             {
 956               gcc_assert (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE);
 957               location_t iloc
 958                 = cp_expr_loc_or_loc (init, DECL_SOURCE_LOCATION (value));
 959               if (friendp)
 960                 error_at (iloc, "initializer specified for friend "
 961                           "function %qD", value);
 962               else
 963                 error_at (iloc, "initializer specified for static "
 964                           "member function %qD", value);
 965             }
 966         }
 967       else if (TREE_CODE (value) == FIELD_DECL)
 968         /* C++11 NSDMI, keep going.  */;
 969       else if (!VAR_P (value))
 970         gcc_unreachable ();
 971     }
 972
 973   /* Pass friend decls back.  */
 974   if ((TREE_CODE (value) == FUNCTION_DECL
 975        || TREE_CODE (value) == TEMPLATE_DECL)
 976       && DECL_CONTEXT (value) != current_class_type)
 977     {
 978       if (attrlist)
 979         cplus_decl_attributes (&value, attrlist, 0);
 980       return value;
 981     }
 982
 983   /* Need to set this before push_template_decl.  */
 984   if (VAR_P (value))
 985     DECL_CONTEXT (value) = current_class_type;
 986
 987   if (processing_template_decl && VAR_OR_FUNCTION_DECL_P (value))
 988     {
 989       value = push_template_decl (value);
 990       if (error_operand_p (value))
 991         return error_mark_node;
 992     }
 993
 994   if (attrlist)
 995     cplus_decl_attributes (&value, attrlist, 0);
 996
 997   if (init && DIRECT_LIST_INIT_P (init))
 998     flags = LOOKUP_NORMAL;
 999   else
1000     flags = LOOKUP_IMPLICIT;
1001
1002   switch (TREE_CODE (value))
1003     {
1004     case VAR_DECL:
1005       finish_static_data_member_decl (value, init, init_const_expr_p,
1006                                       asmspec_tree, flags);
1007       return value;
1008
1009     case FIELD_DECL:
1010       if (asmspec)
1011         error ("%<asm%> specifiers are not permitted on non-static data members");
1012       if (DECL_INITIAL (value) == error_mark_node)
1013         init = error_mark_node;
1014       cp_finish_decl (value, init, /*init_const_expr_p=*/false,
1015                       NULL_TREE, flags);
1016       DECL_IN_AGGR_P (value) = 1;
1017       return value;
1018
1019     case  FUNCTION_DECL:
1020       if (asmspec)
1021         set_user_assembler_name (value, asmspec);
1022
1023       cp_finish_decl (value,
1024                       /*init=*/NULL_TREE,
1025                       /*init_const_expr_p=*/false,
1026                       asmspec_tree, flags);
1027
1028       /* Pass friends back this way.  */
1029       if (DECL_UNIQUE_FRIEND_P (value))
1030         return void_type_node;
1031
1032       DECL_IN_AGGR_P (value) = 1;
1033       return value;
1034
1035     default:
1036       gcc_unreachable ();
1037     }
1038   return NULL_TREE;
1039 }
1040
1041 /* Like `grokfield', but for bitfields.
1042    WIDTH is the width of the bitfield, a constant expression.
1043    The other parameters are as for grokfield.  */
1044
1045 tree
1046 grokbitfield (const cp_declarator *declarator,
1047               cp_decl_specifier_seq *declspecs, tree width, tree init,
1048               tree attrlist)
1049 {
1050   tree value = grokdeclarator (declarator, declspecs, BITFIELD,
1051                                init != NULL_TREE, &attrlist);
1052
1053   if (value == error_mark_node)
1054     return NULL_TREE; /* friends went bad.  */
1055
1056   tree type = TREE_TYPE (value);
1057   if (type == error_mark_node)
1058     return value;
1059
1060   /* Pass friendly classes back.  */
1061   if (VOID_TYPE_P (value))
1062     return void_type_node;
1063
1064   if (!INTEGRAL_OR_ENUMERATION_TYPE_P (type)
1065       && (INDIRECT_TYPE_P (type) || !dependent_type_p (type)))
1066     {
1067       error_at (DECL_SOURCE_LOCATION (value),
1068                 "bit-field %qD with non-integral type %qT",
1069                 value, type);
1070       return error_mark_node;
1071     }
1072
1073   if (TREE_CODE (value) == TYPE_DECL)
1074     {
1075       error_at (DECL_SOURCE_LOCATION (value),
1076                 "cannot declare %qD to be a bit-field type", value);
1077       return NULL_TREE;
1078     }
1079
1080   /* Usually, finish_struct_1 catches bitfields with invalid types.
1081      But, in the case of bitfields with function type, we confuse
1082      ourselves into thinking they are member functions, so we must
1083      check here.  */
1084   if (TREE_CODE (value) == FUNCTION_DECL)
1085     {
1086       error_at (DECL_SOURCE_LOCATION (value),
1087                 "cannot declare bit-field %qD with function type", value);
1088       return NULL_TREE;
1089     }
1090
1091   if (TYPE_WARN_IF_NOT_ALIGN (type))
1092     {
1093       error_at (DECL_SOURCE_LOCATION (value), "cannot declare bit-field "
1094                 "%qD with %<warn_if_not_aligned%> type", value);
1095       return NULL_TREE;
1096     }
1097
1098   if (DECL_IN_AGGR_P (value))
1099     {
1100       error ("%qD is already defined in the class %qT", value,
1101              DECL_CONTEXT (value));
1102       return void_type_node;
1103     }
1104
1105   if (TREE_STATIC (value))
1106     {
1107       error_at (DECL_SOURCE_LOCATION (value),
1108                 "static member %qD cannot be a bit-field", value);
1109       return NULL_TREE;
1110     }
1111
1112   int flags = LOOKUP_IMPLICIT;
1113   if (init && DIRECT_LIST_INIT_P (init))
1114     flags = LOOKUP_NORMAL;
1115   cp_finish_decl (value, init, false, NULL_TREE, flags);
1116
1117   if (width != error_mark_node)
1118     {
1119       /* The width must be an integer type.  */
1120       if (!type_dependent_expression_p (width)
1121           && !INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (TREE_TYPE (width)))
1122         error ("width of bit-field %qD has non-integral type %qT", value,
1123                TREE_TYPE (width));
1124       else if (!check_for_bare_parameter_packs (width))
1125         {
1126           /* Temporarily stash the width in DECL_BIT_FIELD_REPRESENTATIVE.
1127              check_bitfield_decl picks it from there later and sets DECL_SIZE
1128              accordingly.  */
1129           DECL_BIT_FIELD_REPRESENTATIVE (value) = width;
1130           SET_DECL_C_BIT_FIELD (value);
1131         }
1132     }
1133
1134   DECL_IN_AGGR_P (value) = 1;
1135
1136   if (attrlist)
1137     cplus_decl_attributes (&value, attrlist, /*flags=*/0);
1138
1139   return value;
1140 }
1141
1142 \f
1143 /* Returns true iff ATTR is an attribute which needs to be applied at
1144    instantiation time rather than template definition time.  */
1145
1146 static bool
1147 is_late_template_attribute (tree attr, tree decl)
1148 {
1149   tree name = get_attribute_name (attr);
1150   tree args = TREE_VALUE (attr);
1151   const struct attribute_spec *spec = lookup_attribute_spec (name);
1152   tree arg;
1153
1154   if (!spec)
1155     /* Unknown attribute.  */
1156     return false;
1157
1158   /* Attribute weak handling wants to write out assembly right away.  */
1159   if (is_attribute_p ("weak", name))
1160     return true;
1161
1162   /* Attributes used and unused are applied directly to typedefs for the
1163      benefit of maybe_warn_unused_local_typedefs.  */
1164   if (TREE_CODE (decl) == TYPE_DECL
1165       && (is_attribute_p ("unused", name)
1166           || is_attribute_p ("used", name)))
1167     return false;
1168
1169   /* Attribute tls_model wants to modify the symtab.  */
1170   if (is_attribute_p ("tls_model", name))
1171     return true;
1172
1173   /* #pragma omp declare simd attribute needs to be always deferred.  */
1174   if (flag_openmp
1175       && is_attribute_p ("omp declare simd", name))
1176     return true;
1177
1178   if (args == error_mark_node)
1179     return false;
1180
1181   /* An attribute pack is clearly dependent.  */
1182   if (args && PACK_EXPANSION_P (args))
1183     return true;
1184
1185   /* If any of the arguments are dependent expressions, we can't evaluate
1186      the attribute until instantiation time.  */
1187   for (arg = args; arg; arg = TREE_CHAIN (arg))
1188     {
1189       tree t = TREE_VALUE (arg);
1190
1191       /* If the first attribute argument is an identifier, only consider
1192          second and following arguments.  Attributes like mode, format,
1193          cleanup and several target specific attributes aren't late
1194          just because they have an IDENTIFIER_NODE as first argument.  */
1195       if (arg == args && attribute_takes_identifier_p (name)
1196           && identifier_p (t))
1197         continue;
1198
1199       if (value_dependent_expression_p (t))
1200         return true;
1201     }
1202
1203   if (TREE_CODE (decl) == TYPE_DECL
1204       || TYPE_P (decl)
1205       || spec->type_required)
1206     {
1207       tree type = TYPE_P (decl) ? decl : TREE_TYPE (decl);
1208
1209       /* We can't apply any attributes to a completely unknown type until
1210          instantiation time.  */
1211       enum tree_code code = TREE_CODE (type);
1212       if (code == TEMPLATE_TYPE_PARM
1213           || code == BOUND_TEMPLATE_TEMPLATE_PARM
1214           || code == TYPENAME_TYPE)
1215         return true;
1216       /* Also defer most attributes on dependent types.  This is not
1217          necessary in all cases, but is the better default.  */
1218       else if (dependent_type_p (type)
1219                /* But some attributes specifically apply to templates.  */
1220                && !is_attribute_p ("abi_tag", name)
1221                && !is_attribute_p ("deprecated", name)
1222                && !is_attribute_p ("visibility", name))
1223         return true;
1224       else
1225         return false;
1226     }
1227   else
1228     return false;
1229 }
1230
1231 /* ATTR_P is a list of attributes.  Remove any attributes which need to be
1232    applied at instantiation time and return them.  If IS_DEPENDENT is true,
1233    the declaration itself is dependent, so all attributes should be applied
1234    at instantiation time.  */
1235
1236 tree
1237 splice_template_attributes (tree *attr_p, tree decl)
1238 {
1239   tree *p = attr_p;
1240   tree late_attrs = NULL_TREE;
1241   tree *q = &late_attrs;
1242
1243   if (!p)
1244     return NULL_TREE;
1245
1246   for (; *p; )
1247     {
1248       if (is_late_template_attribute (*p, decl))
1249         {
1250           ATTR_IS_DEPENDENT (*p) = 1;
1251           *q = *p;
1252           *p = TREE_CHAIN (*p);
1253           q = &TREE_CHAIN (*q);
1254           *q = NULL_TREE;
1255         }
1256       else
1257         p = &TREE_CHAIN (*p);
1258     }
1259
1260   return late_attrs;
1261 }
1262
1263 /* Remove any late attributes from the list in ATTR_P and attach them to
1264    DECL_P.  */
1265
1266 static void
1267 save_template_attributes (tree *attr_p, tree *decl_p, int flags)
1268 {
1269   tree *q;
1270
1271   if (attr_p && *attr_p == error_mark_node)
1272     return;
1273
1274   tree late_attrs = splice_template_attributes (attr_p, *decl_p);
1275   if (!late_attrs)
1276     return;
1277
1278   if (DECL_P (*decl_p))
1279     q = &DECL_ATTRIBUTES (*decl_p);
1280   else
1281     q = &TYPE_ATTRIBUTES (*decl_p);
1282
1283   tree old_attrs = *q;
1284
1285   /* Place the late attributes at the beginning of the attribute
1286      list.  */
1287   late_attrs = chainon (late_attrs, *q);
1288   if (*q != late_attrs
1289       && !DECL_P (*decl_p)
1290       && !(flags & ATTR_FLAG_TYPE_IN_PLACE))
1291     {
1292       if (!dependent_type_p (*decl_p))
1293         *decl_p = cp_build_type_attribute_variant (*decl_p, late_attrs);
1294       else
1295         {
1296           *decl_p = build_variant_type_copy (*decl_p);
1297           TYPE_ATTRIBUTES (*decl_p) = late_attrs;
1298         }
1299     }
1300   else
1301     *q = late_attrs;
1302
1303   if (!DECL_P (*decl_p) && *decl_p == TYPE_MAIN_VARIANT (*decl_p))
1304     {
1305       /* We've added new attributes directly to the main variant, so
1306          now we need to update all of the other variants to include
1307          these new attributes.  */
1308       tree variant;
1309       for (variant = TYPE_NEXT_VARIANT (*decl_p); variant;
1310            variant = TYPE_NEXT_VARIANT (variant))
1311         {
1312           gcc_assert (TYPE_ATTRIBUTES (variant) == old_attrs);
1313           TYPE_ATTRIBUTES (variant) = TYPE_ATTRIBUTES (*decl_p);
1314         }
1315     }
1316 }
1317
1318 /* True if ATTRS contains any dependent attributes that affect type
1319    identity.  */
1320
1321 bool
1322 any_dependent_type_attributes_p (tree attrs)
1323 {
1324   for (tree a = attrs; a; a = TREE_CHAIN (a))
1325     if (ATTR_IS_DEPENDENT (a))
1326       {
1327         const attribute_spec *as = lookup_attribute_spec (TREE_PURPOSE (a));
1328         if (as && as->affects_type_identity)
1329           return true;
1330       }
1331   return false;
1332 }
1333
1334 /* Return true iff ATTRS are acceptable attributes to be applied in-place
1335    to a typedef which gives a previously unnamed class or enum a name for
1336    linkage purposes.  */
1337
1338 bool
1339 attributes_naming_typedef_ok (tree attrs)
1340 {
1341   for (; attrs; attrs = TREE_CHAIN (attrs))
1342     {
1343       tree name = get_attribute_name (attrs);
1344       if (is_attribute_p ("vector_size", name))
1345         return false;
1346     }
1347   return true;
1348 }
1349
1350 /* Like reconstruct_complex_type, but handle also template trees.  */
1351
1352 tree
1353 cp_reconstruct_complex_type (tree type, tree bottom)
1354 {
1355   tree inner, outer;
1356
1357   if (TYPE_PTR_P (type))
1358     {
1359       inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
1360       outer = build_pointer_type_for_mode (inner, TYPE_MODE (type),
1361                                            TYPE_REF_CAN_ALIAS_ALL (type));
1362     }
1363   else if (TYPE_REF_P (type))
1364     {
1365       inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
1366       outer = build_reference_type_for_mode (inner, TYPE_MODE (type),
1367                                              TYPE_REF_CAN_ALIAS_ALL (type));
1368     }
1369   else if (TREE_CODE (type) == ARRAY_TYPE)
1370     {
1371       inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
1372       outer = build_cplus_array_type (inner, TYPE_DOMAIN (type));
1373       /* Don't call cp_build_qualified_type on ARRAY_TYPEs, the
1374          element type qualification will be handled by the recursive
1375          cp_reconstruct_complex_type call and cp_build_qualified_type
1376          for ARRAY_TYPEs changes the element type.  */
1377       return outer;
1378     }
1379   else if (TREE_CODE (type) == FUNCTION_TYPE)
1380     {
1381       inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
1382       outer = build_function_type (inner, TYPE_ARG_TYPES (type));
1383       outer = apply_memfn_quals (outer, type_memfn_quals (type));
1384     }
1385   else if (TREE_CODE (type) == METHOD_TYPE)
1386     {
1387       inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
1388       /* The build_method_type_directly() routine prepends 'this' to argument list,
1389          so we must compensate by getting rid of it.  */
1390       outer
1391         = build_method_type_directly
1392             (class_of_this_parm (type), inner,
1393              TREE_CHAIN (TYPE_ARG_TYPES (type)));
1394     }
1395   else if (TREE_CODE (type) == OFFSET_TYPE)
1396     {
1397       inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
1398       outer = build_offset_type (TYPE_OFFSET_BASETYPE (type), inner);
1399     }
1400   else
1401     return bottom;
1402
1403   if (TYPE_ATTRIBUTES (type))
1404     outer = cp_build_type_attribute_variant (outer, TYPE_ATTRIBUTES (type));
1405   outer = cp_build_qualified_type (outer, cp_type_quals (type));
1406   outer = cxx_copy_lang_qualifiers (outer, type);
1407
1408   return outer;
1409 }
1410
1411 /* Replaces any constexpr expression that may be into the attributes
1412    arguments with their reduced value.  */
1413
1414 void
1415 cp_check_const_attributes (tree attributes)
1416 {
1417   if (attributes == error_mark_node)
1418     return;
1419
1420   tree attr;
1421   for (attr = attributes; attr; attr = TREE_CHAIN (attr))
1422     {
1423       tree arg;
1424       for (arg = TREE_VALUE (attr); arg && TREE_CODE (arg) == TREE_LIST;
1425            arg = TREE_CHAIN (arg))
1426         {
1427           tree expr = TREE_VALUE (arg);
1428           if (EXPR_P (expr))
1429             TREE_VALUE (arg) = fold_non_dependent_expr (expr);
1430         }
1431     }
1432 }
1433
1434 /* Return true if TYPE is an OpenMP mappable type.
1435    If NOTES is non-zero, emit a note message for each problem.  */
1436 static bool
1437 cp_omp_mappable_type_1 (tree type, bool notes)
1438 {
1439   bool result = true;
1440
1441   /* Mappable type has to be complete.  */
1442   if (type == error_mark_node || !COMPLETE_TYPE_P (type))
1443     {
1444       if (notes && type != error_mark_node)
1445         {
1446           tree decl = TYPE_MAIN_DECL (type);
1447           inform ((decl ? DECL_SOURCE_LOCATION (decl) : input_location),
1448                   "incomplete type %qT is not mappable", type);
1449         }
1450       result = false;
1451     }
1452   /* Arrays have mappable type if the elements have mappable type.  */
1453   while (TREE_CODE (type) == ARRAY_TYPE)
1454     type = TREE_TYPE (type);
1455   /* A mappable type cannot contain virtual members.  */
1456   if (CLASS_TYPE_P (type) && CLASSTYPE_VTABLES (type))
1457     {
1458       if (notes)
1459         inform (DECL_SOURCE_LOCATION (TYPE_MAIN_DECL (type)),
1460                 "type %qT with virtual members is not mappable", type);
1461       result = false;
1462     }
1463   /* All data members must be non-static.  */
1464   if (CLASS_TYPE_P (type))
1465     {
1466       tree field;
1467       for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
1468         if (VAR_P (field))
1469           {
1470             if (notes)
1471               inform (DECL_SOURCE_LOCATION (field),
1472                       "static field %qD is not mappable", field);
1473             result = false;
1474           }
1475         /* All fields must have mappable types.  */
1476         else if (TREE_CODE (field) == FIELD_DECL
1477                  && !cp_omp_mappable_type_1 (TREE_TYPE (field), notes))
1478           result = false;
1479     }
1480   return result;
1481 }
1482
1483 /* Return true if TYPE is an OpenMP mappable type.  */
1484 bool
1485 cp_omp_mappable_type (tree type)
1486 {
1487   return cp_omp_mappable_type_1 (type, false);
1488 }
1489
1490 /* Return true if TYPE is an OpenMP mappable type.
1491    Emit an error messages if not.  */
1492 bool
1493 cp_omp_emit_unmappable_type_notes (tree type)
1494 {
1495   return cp_omp_mappable_type_1 (type, true);
1496 }
1497
1498 /* Return the last pushed declaration for the symbol DECL or NULL
1499    when no such declaration exists.  */
1500
1501 static tree
1502 find_last_decl (tree decl)
1503 {
1504   tree last_decl = NULL_TREE;
1505
1506   if (tree name = DECL_P (decl) ? DECL_NAME (decl) : NULL_TREE)
1507     {
1508       /* Look up the declaration in its scope.  */
1509       tree pushed_scope = NULL_TREE;
1510       if (tree ctype = DECL_CONTEXT (decl))
1511         pushed_scope = push_scope (ctype);
1512
1513       last_decl = lookup_name (name);
1514
1515       if (pushed_scope)
1516         pop_scope (pushed_scope);
1517
1518       /* The declaration may be a member conversion operator
1519          or a bunch of overfloads (handle the latter below).  */
1520       if (last_decl && BASELINK_P (last_decl))
1521         last_decl = BASELINK_FUNCTIONS (last_decl);
1522     }
1523
1524   if (!last_decl)
1525     return NULL_TREE;
1526
1527   if (DECL_P (last_decl) || TREE_CODE (last_decl) == OVERLOAD)
1528     {
1529       /* A set of overloads of the same function.  */
1530       for (lkp_iterator iter (last_decl); iter; ++iter)
1531         {
1532           if (TREE_CODE (*iter) == OVERLOAD)
1533             continue;
1534
1535           if (decls_match (decl, *iter, /*record_decls=*/false))
1536             return *iter;
1537         }
1538       return NULL_TREE;
1539     }
1540
1541   return NULL_TREE;
1542 }
1543
1544 /* Like decl_attributes, but handle C++ complexity.  */
1545
1546 void
1547 cplus_decl_attributes (tree *decl, tree attributes, int flags)
1548 {
1549   if (*decl == NULL_TREE || *decl == void_type_node
1550       || *decl == error_mark_node)
1551     return;
1552
1553   /* Add implicit "omp declare target" attribute if requested.  */
1554   if (vec_safe_length (scope_chain->omp_declare_target_attribute)
1555       && ((VAR_P (*decl)
1556            && (TREE_STATIC (*decl) || DECL_EXTERNAL (*decl)))
1557           || TREE_CODE (*decl) == FUNCTION_DECL))
1558     {
1559       if (VAR_P (*decl)
1560           && DECL_CLASS_SCOPE_P (*decl))
1561         error ("%q+D static data member inside of declare target directive",
1562                *decl);
1563       else if (VAR_P (*decl)
1564                && (processing_template_decl
1565                    || !cp_omp_mappable_type (TREE_TYPE (*decl))))
1566         attributes = tree_cons (get_identifier ("omp declare target implicit"),
1567                                 NULL_TREE, attributes);
1568       else
1569         {
1570           attributes = tree_cons (get_identifier ("omp declare target"),
1571                                   NULL_TREE, attributes);
1572           attributes = tree_cons (get_identifier ("omp declare target block"),
1573                                   NULL_TREE, attributes);
1574         }
1575     }
1576
1577   if (processing_template_decl)
1578     {
1579       if (check_for_bare_parameter_packs (attributes))
1580         return;
1581
1582       save_template_attributes (&attributes, decl, flags);
1583     }
1584
1585   cp_check_const_attributes (attributes);
1586
1587   if ((flag_openmp || flag_openmp_simd) && attributes != error_mark_node)
1588     {
1589       bool diagnosed = false;
1590       for (tree *pa = &attributes; *pa; )
1591         {
1592           if (get_attribute_namespace (*pa) == omp_identifier)
1593             {
1594               tree name = get_attribute_name (*pa);
1595               if (is_attribute_p ("directive", name)
1596                   || is_attribute_p ("sequence", name))
1597                 {
1598                   if (!diagnosed)
1599                     {
1600                       error ("%<omp::%E%> not allowed to be specified in this "
1601                              "context", name);
1602                       diagnosed = true;
1603                     }
1604                   *pa = TREE_CHAIN (*pa);
1605                   continue;
1606                 }
1607             }
1608           pa = &TREE_CHAIN (*pa);
1609         }
1610     }
1611
1612   if (TREE_CODE (*decl) == TEMPLATE_DECL)
1613     decl = &DECL_TEMPLATE_RESULT (*decl);
1614
1615   if (TREE_TYPE (*decl) && TYPE_PTRMEMFUNC_P (TREE_TYPE (*decl)))
1616     {
1617       attributes
1618         = decl_attributes (decl, attributes, flags | ATTR_FLAG_FUNCTION_NEXT);
1619       decl_attributes (&TYPE_PTRMEMFUNC_FN_TYPE_RAW (TREE_TYPE (*decl)),
1620                        attributes, flags);
1621     }
1622   else
1623     {
1624       tree last_decl = find_last_decl (*decl);
1625       decl_attributes (decl, attributes, flags, last_decl);
1626     }
1627
1628   /* Propagate deprecation out to the template.  */
1629   if (TREE_DEPRECATED (*decl))
1630     if (tree ti = get_template_info (*decl))
1631       {
1632         tree tmpl = TI_TEMPLATE (ti);
1633         tree pattern = (TYPE_P (*decl) ? TREE_TYPE (tmpl)
1634                         : DECL_TEMPLATE_RESULT (tmpl));
1635         if (*decl == pattern)
1636           TREE_DEPRECATED (tmpl) = true;
1637       }
1638 }
1639 \f
1640 /* Walks through the namespace- or function-scope anonymous union
1641    OBJECT, with the indicated TYPE, building appropriate VAR_DECLs.
1642    Returns one of the fields for use in the mangled name.  */
1643
1644 static tree
1645 build_anon_union_vars (tree type, tree object)
1646 {
1647   tree main_decl = NULL_TREE;
1648   tree field;
1649
1650   /* Rather than write the code to handle the non-union case,
1651      just give an error.  */
1652   if (TREE_CODE (type) != UNION_TYPE)
1653     {
1654       error_at (DECL_SOURCE_LOCATION (TYPE_MAIN_DECL (type)),
1655                 "anonymous struct not inside named type");
1656       return error_mark_node;
1657     }
1658
1659   for (field = TYPE_FIELDS (type);
1660        field != NULL_TREE;
1661        field = DECL_CHAIN (field))
1662     {
1663       tree decl;
1664       tree ref;
1665
1666       if (DECL_ARTIFICIAL (field))
1667         continue;
1668       if (TREE_CODE (field) != FIELD_DECL)
1669         {
1670           permerror (DECL_SOURCE_LOCATION (field),
1671                      "%q#D invalid; an anonymous union can only "
1672                      "have non-static data members", field);
1673           continue;
1674         }
1675
1676       if (TREE_PRIVATE (field))
1677         permerror (DECL_SOURCE_LOCATION (field),
1678                    "private member %q#D in anonymous union", field);
1679       else if (TREE_PROTECTED (field))
1680         permerror (DECL_SOURCE_LOCATION (field),
1681                    "protected member %q#D in anonymous union", field);
1682
1683       if (processing_template_decl)
1684         ref = build_min_nt_loc (UNKNOWN_LOCATION, COMPONENT_REF, object,
1685                                 DECL_NAME (field), NULL_TREE);
1686       else
1687         ref = build_class_member_access_expr (object, field, NULL_TREE,
1688                                               false, tf_warning_or_error);
1689
1690       if (DECL_NAME (field))
1691         {
1692           tree base;
1693
1694           decl = build_decl (input_location,
1695                              VAR_DECL, DECL_NAME (field), TREE_TYPE (field));
1696           DECL_ANON_UNION_VAR_P (decl) = 1;
1697           DECL_ARTIFICIAL (decl) = 1;
1698
1699           base = get_base_address (object);
1700           TREE_PUBLIC (decl) = TREE_PUBLIC (base);
1701           TREE_STATIC (decl) = TREE_STATIC (base);
1702           DECL_EXTERNAL (decl) = DECL_EXTERNAL (base);
1703
1704           SET_DECL_VALUE_EXPR (decl, ref);
1705           DECL_HAS_VALUE_EXPR_P (decl) = 1;
1706
1707           decl = pushdecl (decl);
1708         }
1709       else if (ANON_AGGR_TYPE_P (TREE_TYPE (field)))
1710         decl = build_anon_union_vars (TREE_TYPE (field), ref);
1711       else
1712         decl = 0;
1713
1714       if (main_decl == NULL_TREE)
1715         main_decl = decl;
1716     }
1717
1718   return main_decl;
1719 }
1720
1721 /* Finish off the processing of a UNION_TYPE structure.  If the union is an
1722    anonymous union, then all members must be laid out together.  PUBLIC_P
1723    is nonzero if this union is not declared static.  */
1724
1725 void
1726 finish_anon_union (tree anon_union_decl)
1727 {
1728   tree type;
1729   tree main_decl;
1730   bool public_p;
1731
1732   if (anon_union_decl == error_mark_node)
1733     return;
1734
1735   type = TREE_TYPE (anon_union_decl);
1736   public_p = TREE_PUBLIC (anon_union_decl);
1737
1738   /* The VAR_DECL's context is the same as the TYPE's context.  */
1739   DECL_CONTEXT (anon_union_decl) = DECL_CONTEXT (TYPE_NAME (type));
1740
1741   if (TYPE_FIELDS (type) == NULL_TREE)
1742     return;
1743
1744   if (public_p)
1745     {
1746       error ("namespace-scope anonymous aggregates must be static");
1747       return;
1748     }
1749
1750   main_decl = build_anon_union_vars (type, anon_union_decl);
1751   if (main_decl == error_mark_node)
1752     return;
1753   if (main_decl == NULL_TREE)
1754     {
1755       pedwarn (input_location, 0, "anonymous union with no members");
1756       return;
1757     }
1758
1759   if (!processing_template_decl)
1760     {
1761       /* Use main_decl to set the mangled name.  */
1762       DECL_NAME (anon_union_decl) = DECL_NAME (main_decl);
1763       maybe_commonize_var (anon_union_decl);
1764       if (TREE_STATIC (anon_union_decl) || DECL_EXTERNAL (anon_union_decl))
1765         {
1766           if (DECL_DISCRIMINATOR_P (anon_union_decl))
1767             determine_local_discriminator (anon_union_decl);
1768           mangle_decl (anon_union_decl);
1769         }
1770       DECL_NAME (anon_union_decl) = NULL_TREE;
1771     }
1772
1773   pushdecl (anon_union_decl);
1774   cp_finish_decl (anon_union_decl, NULL_TREE, false, NULL_TREE, 0);
1775 }
1776 \f
1777 /* Auxiliary functions to make type signatures for
1778    `operator new' and `operator delete' correspond to
1779    what compiler will be expecting.  */
1780
1781 tree
1782 coerce_new_type (tree type, location_t loc)
1783 {
1784   int e = 0;
1785   tree args = TYPE_ARG_TYPES (type);
1786
1787   gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);
1788
1789   if (!same_type_p (TREE_TYPE (type), ptr_type_node))
1790     {
1791       e = 1;
1792       error_at (loc, "%<operator new%> must return type %qT",
1793                 ptr_type_node);
1794     }
1795
1796   if (args && args != void_list_node)
1797     {
1798       if (TREE_PURPOSE (args))
1799         {
1800           /* [basic.stc.dynamic.allocation]
1801
1802              The first parameter shall not have an associated default
1803              argument.  */
1804           error_at (loc, "the first parameter of %<operator new%> cannot "
1805                     "have a default argument");
1806           /* Throw away the default argument.  */
1807           TREE_PURPOSE (args) = NULL_TREE;
1808         }
1809
1810       if (!same_type_p (TREE_VALUE (args), size_type_node))
1811         {
1812           e = 2;
1813           args = TREE_CHAIN (args);
1814         }
1815     }
1816   else
1817     e = 2;
1818
1819   if (e == 2)
1820     permerror (loc, "%<operator new%> takes type %<size_t%> (%qT) "
1821                "as first parameter", size_type_node);
1822
1823   switch (e)
1824   {
1825     case 2:
1826       args = tree_cons (NULL_TREE, size_type_node, args);
1827       /* Fall through.  */
1828     case 1:
1829       type = (cxx_copy_lang_qualifiers
1830               (build_function_type (ptr_type_node, args),
1831                type));
1832       /* Fall through.  */
1833     default:;
1834   }
1835   return type;
1836 }
1837
1838 void
1839 coerce_delete_type (tree decl, location_t loc)
1840 {
1841   int e = 0;
1842   tree type = TREE_TYPE (decl);
1843   tree args = TYPE_ARG_TYPES (type);
1844
1845   gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);
1846
1847   if (!same_type_p (TREE_TYPE (type), void_type_node))
1848     {
1849       e = 1;
1850       error_at (loc, "%<operator delete%> must return type %qT",
1851                 void_type_node);
1852     }
1853
1854   tree ptrtype = ptr_type_node;
1855   if (destroying_delete_p (decl))
1856     {
1857       if (DECL_CLASS_SCOPE_P (decl))
1858         /* If the function is a destroying operator delete declared in class
1859            type C, the type of its first parameter shall be C*.  */
1860         ptrtype = build_pointer_type (DECL_CONTEXT (decl));
1861       else
1862         /* A destroying operator delete shall be a class member function named
1863            operator delete.  */
1864         error_at (loc,
1865                   "destroying %<operator delete%> must be a member function");
1866       const ovl_op_info_t *op = IDENTIFIER_OVL_OP_INFO (DECL_NAME (decl));
1867       if (op->flags & OVL_OP_FLAG_VEC)
1868         error_at (loc, "%<operator delete[]%> cannot be a destroying delete");
1869       if (!usual_deallocation_fn_p (decl))
1870         error_at (loc, "destroying %<operator delete%> must be a usual "
1871                   "deallocation function");
1872     }
1873
1874   if (!args || args == void_list_node
1875       || !same_type_p (TREE_VALUE (args), ptrtype))
1876     {
1877       e = 2;
1878       if (args && args != void_list_node)
1879         args = TREE_CHAIN (args);
1880       error_at (loc, "%<operator delete%> takes type %qT as first parameter",
1881                 ptrtype);
1882     }
1883   switch (e)
1884   {
1885     case 2:
1886       args = tree_cons (NULL_TREE, ptrtype, args);
1887       /* Fall through.  */
1888     case 1:
1889       type = (cxx_copy_lang_qualifiers
1890               (build_function_type (void_type_node, args),
1891                type));
1892       /* Fall through.  */
1893     default:;
1894   }
1895
1896   TREE_TYPE (decl) = type;
1897 }
1898 \f
1899 /* DECL is a VAR_DECL for a vtable: walk through the entries in the vtable
1900    and mark them as needed.  */
1901
1902 static void
1903 mark_vtable_entries (tree decl, vec<tree> &consteval_vtables)
1904 {
1905   tree fnaddr;
1906   unsigned HOST_WIDE_INT idx;
1907
1908   /* It's OK for the vtable to refer to deprecated virtual functions.  */
1909   warning_sentinel w(warn_deprecated_decl);
1910
1911   bool consteval_seen = false;
1912
1913   FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (DECL_INITIAL (decl)),
1914                               idx, fnaddr)
1915     {
1916       tree fn;
1917
1918       STRIP_NOPS (fnaddr);
1919
1920       if (TREE_CODE (fnaddr) != ADDR_EXPR
1921           && TREE_CODE (fnaddr) != FDESC_EXPR)
1922         /* This entry is an offset: a virtual base class offset, a
1923            virtual call offset, an RTTI offset, etc.  */
1924         continue;
1925
1926       fn = TREE_OPERAND (fnaddr, 0);
1927       if (TREE_CODE (fn) == FUNCTION_DECL && DECL_IMMEDIATE_FUNCTION_P (fn))
1928         {
1929           if (!consteval_seen)
1930             {
1931               consteval_seen = true;
1932               consteval_vtables.safe_push (decl);
1933             }
1934           continue;
1935         }
1936       TREE_ADDRESSABLE (fn) = 1;
1937       /* When we don't have vcall offsets, we output thunks whenever
1938          we output the vtables that contain them.  With vcall offsets,
1939          we know all the thunks we'll need when we emit a virtual
1940          function, so we emit the thunks there instead.  */
1941       if (DECL_THUNK_P (fn))
1942         use_thunk (fn, /*emit_p=*/0);
1943       /* Set the location, as marking the function could cause
1944          instantiation.  We do not need to preserve the incoming
1945          location, as we're called from c_parse_final_cleanups, which
1946          takes care of that.  */
1947       input_location = DECL_SOURCE_LOCATION (fn);
1948       mark_used (fn);
1949     }
1950 }
1951
1952 /* Replace any consteval functions in vtables with null pointers.  */
1953
1954 static void
1955 clear_consteval_vfns (vec<tree> &consteval_vtables)
1956 {
1957   for (tree vtable : consteval_vtables)
1958     for (constructor_elt &elt : CONSTRUCTOR_ELTS (DECL_INITIAL (vtable)))
1959       {
1960         tree fn = cp_get_fndecl_from_callee (elt.value, /*fold*/false);
1961         if (fn && DECL_IMMEDIATE_FUNCTION_P (fn))
1962           elt.value = build_zero_cst (vtable_entry_type);
1963       }
1964 }
1965
1966 /* Adjust the TLS model on variable DECL if need be, typically after
1967    the linkage of DECL has been modified.  */
1968
1969 static void
1970 adjust_var_decl_tls_model (tree decl)
1971 {
1972   if (CP_DECL_THREAD_LOCAL_P (decl)
1973       && !lookup_attribute ("tls_model", DECL_ATTRIBUTES (decl)))
1974     set_decl_tls_model (decl, decl_default_tls_model (decl));
1975 }
1976
1977 /* Set DECL up to have the closest approximation of "initialized common"
1978    linkage available.  */
1979
1980 void
1981 comdat_linkage (tree decl)
1982 {
1983   if (flag_weak)
1984     make_decl_one_only (decl, cxx_comdat_group (decl));
1985   else if (TREE_CODE (decl) == FUNCTION_DECL
1986            || (VAR_P (decl) && DECL_ARTIFICIAL (decl)))
1987     /* We can just emit function and compiler-generated variables
1988        statically; having multiple copies is (for the most part) only
1989        a waste of space.
1990
1991        There are two correctness issues, however: the address of a
1992        template instantiation with external linkage should be the
1993        same, independent of what translation unit asks for the
1994        address, and this will not hold when we emit multiple copies of
1995        the function.  However, there's little else we can do.
1996
1997        Also, by default, the typeinfo implementation assumes that
1998        there will be only one copy of the string used as the name for
1999        each type.  Therefore, if weak symbols are unavailable, the
2000        run-time library should perform a more conservative check; it
2001        should perform a string comparison, rather than an address
2002        comparison.  */
2003     TREE_PUBLIC (decl) = 0;
2004   else
2005     {
2006       /* Static data member template instantiations, however, cannot
2007          have multiple copies.  */
2008       if (DECL_INITIAL (decl) == 0
2009           || DECL_INITIAL (decl) == error_mark_node)
2010         DECL_COMMON (decl) = 1;
2011       else if (EMPTY_CONSTRUCTOR_P (DECL_INITIAL (decl)))
2012         {
2013           DECL_COMMON (decl) = 1;
2014           DECL_INITIAL (decl) = error_mark_node;
2015         }
2016       else if (!DECL_EXPLICIT_INSTANTIATION (decl))
2017         {
2018           /* We can't do anything useful; leave vars for explicit
2019              instantiation.  */
2020           DECL_EXTERNAL (decl) = 1;
2021           DECL_NOT_REALLY_EXTERN (decl) = 0;
2022         }
2023     }
2024
2025   if (TREE_PUBLIC (decl))
2026     DECL_COMDAT (decl) = 1;
2027
2028   if (VAR_P (decl))
2029     adjust_var_decl_tls_model (decl);
2030 }
2031
2032 /* For win32 we also want to put explicit instantiations in
2033    linkonce sections, so that they will be merged with implicit
2034    instantiations; otherwise we get duplicate symbol errors.
2035    For Darwin we do not want explicit instantiations to be
2036    linkonce.  */
2037
2038 void
2039 maybe_make_one_only (tree decl)
2040 {
2041   /* We used to say that this was not necessary on targets that support weak
2042      symbols, because the implicit instantiations will defer to the explicit
2043      one.  However, that's not actually the case in SVR4; a strong definition
2044      after a weak one is an error.  Also, not making explicit
2045      instantiations one_only means that we can end up with two copies of
2046      some template instantiations.  */
2047   if (! flag_weak)
2048     return;
2049
2050   /* We can't set DECL_COMDAT on functions, or cp_finish_file will think
2051      we can get away with not emitting them if they aren't used.  We need
2052      to for variables so that cp_finish_decl will update their linkage,
2053      because their DECL_INITIAL may not have been set properly yet.  */
2054
2055   if (!TARGET_WEAK_NOT_IN_ARCHIVE_TOC
2056       || (! DECL_EXPLICIT_INSTANTIATION (decl)
2057           && ! DECL_TEMPLATE_SPECIALIZATION (decl)))
2058     {
2059       make_decl_one_only (decl, cxx_comdat_group (decl));
2060
2061       if (VAR_P (decl))
2062         {
2063           varpool_node *node = varpool_node::get_create (decl);
2064           DECL_COMDAT (decl) = 1;
2065           /* Mark it needed so we don't forget to emit it.  */
2066           node->forced_by_abi = true;
2067           TREE_USED (decl) = 1;
2068
2069           adjust_var_decl_tls_model (decl);
2070         }
2071     }
2072 }
2073
2074 /* Returns true iff DECL, a FUNCTION_DECL or VAR_DECL, has vague linkage.
2075    This predicate will give the right answer during parsing of the
2076    function, which other tests may not.  */
2077
2078 bool
2079 vague_linkage_p (tree decl)
2080 {
2081   if (!TREE_PUBLIC (decl))
2082     {
2083       /* maybe_thunk_body clears TREE_PUBLIC and DECL_ABSTRACT_P on the
2084          maybe-in-charge 'tor variants; in that case we need to check one of
2085          the "clones" for the real linkage.  But only in that case; before
2086          maybe_clone_body we haven't yet copied the linkage to the clones.  */
2087       if (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl)
2088           && !DECL_ABSTRACT_P (decl)
2089           && DECL_CHAIN (decl)
2090           && DECL_CLONED_FUNCTION_P (DECL_CHAIN (decl)))
2091         return vague_linkage_p (DECL_CHAIN (decl));
2092
2093       gcc_checking_assert (!DECL_COMDAT (decl));
2094       return false;
2095     }
2096   /* Unfortunately, import_export_decl has not always been called
2097      before the function is processed, so we cannot simply check
2098      DECL_COMDAT.  */
2099   if (DECL_COMDAT (decl)
2100       || (TREE_CODE (decl) == FUNCTION_DECL
2101           && DECL_DECLARED_INLINE_P (decl))
2102       || (DECL_LANG_SPECIFIC (decl)
2103           && DECL_TEMPLATE_INSTANTIATION (decl))
2104       || (VAR_P (decl) && DECL_INLINE_VAR_P (decl)))
2105     return true;
2106   else if (DECL_FUNCTION_SCOPE_P (decl))
2107     /* A local static in an inline effectively has vague linkage.  */
2108     return (TREE_STATIC (decl)
2109             && vague_linkage_p (DECL_CONTEXT (decl)));
2110   else
2111     return false;
2112 }
2113
2114 /* Determine whether or not we want to specifically import or export CTYPE,
2115    using various heuristics.  */
2116
2117 static void
2118 import_export_class (tree ctype)
2119 {
2120   /* -1 for imported, 1 for exported.  */
2121   int import_export = 0;
2122
2123   /* It only makes sense to call this function at EOF.  The reason is
2124      that this function looks at whether or not the first non-inline
2125      non-abstract virtual member function has been defined in this
2126      translation unit.  But, we can't possibly know that until we've
2127      seen the entire translation unit.  */
2128   gcc_assert (at_eof);
2129
2130   if (CLASSTYPE_INTERFACE_KNOWN (ctype))
2131     return;
2132
2133   /* If MULTIPLE_SYMBOL_SPACES is set and we saw a #pragma interface,
2134      we will have CLASSTYPE_INTERFACE_ONLY set but not
2135      CLASSTYPE_INTERFACE_KNOWN.  In that case, we don't want to use this
2136      heuristic because someone will supply a #pragma implementation
2137      elsewhere, and deducing it here would produce a conflict.  */
2138   if (CLASSTYPE_INTERFACE_ONLY (ctype))
2139     return;
2140
2141   if (lookup_attribute ("dllimport", TYPE_ATTRIBUTES (ctype)))
2142     import_export = -1;
2143   else if (lookup_attribute ("dllexport", TYPE_ATTRIBUTES (ctype)))
2144     import_export = 1;
2145   else if (CLASSTYPE_IMPLICIT_INSTANTIATION (ctype)
2146            && !flag_implicit_templates)
2147     /* For a template class, without -fimplicit-templates, check the
2148        repository.  If the virtual table is assigned to this
2149        translation unit, then export the class; otherwise, import
2150        it.  */
2151       import_export = -1;
2152   else if (TYPE_POLYMORPHIC_P (ctype))
2153     {
2154       /* The ABI specifies that the virtual table and associated
2155          information are emitted with the key method, if any.  */
2156       tree method = CLASSTYPE_KEY_METHOD (ctype);
2157       /* If weak symbol support is not available, then we must be
2158          careful not to emit the vtable when the key function is
2159          inline.  An inline function can be defined in multiple
2160          translation units.  If we were to emit the vtable in each
2161          translation unit containing a definition, we would get
2162          multiple definition errors at link-time.  */
2163       if (method && (flag_weak || ! DECL_DECLARED_INLINE_P (method)))
2164         import_export = (DECL_REALLY_EXTERN (method) ? -1 : 1);
2165     }
2166
2167   /* When MULTIPLE_SYMBOL_SPACES is set, we cannot count on seeing
2168      a definition anywhere else.  */
2169   if (MULTIPLE_SYMBOL_SPACES && import_export == -1)
2170     import_export = 0;
2171
2172   /* Allow back ends the chance to overrule the decision.  */
2173   if (targetm.cxx.import_export_class)
2174     import_export = targetm.cxx.import_export_class (ctype, import_export);
2175
2176   if (import_export)
2177     {
2178       SET_CLASSTYPE_INTERFACE_KNOWN (ctype);
2179       CLASSTYPE_INTERFACE_ONLY (ctype) = (import_export < 0);
2180     }
2181 }
2182
2183 /* Return true if VAR has already been provided to the back end; in that
2184    case VAR should not be modified further by the front end.  */
2185 static bool
2186 var_finalized_p (tree var)
2187 {
2188   return varpool_node::get_create (var)->definition;
2189 }
2190
2191 /* DECL is a VAR_DECL or FUNCTION_DECL which, for whatever reason,
2192    must be emitted in this translation unit.  Mark it as such.  */
2193
2194 void
2195 mark_needed (tree decl)
2196 {
2197   TREE_USED (decl) = 1;
2198   if (TREE_CODE (decl) == FUNCTION_DECL)
2199     {
2200       /* Extern inline functions don't become needed when referenced.
2201          If we know a method will be emitted in other TU and no new
2202          functions can be marked reachable, just use the external
2203          definition.  */
2204       struct cgraph_node *node = cgraph_node::get_create (decl);
2205       node->forced_by_abi = true;
2206
2207       /* #pragma interface can call mark_needed for
2208           maybe-in-charge 'tors; mark the clones as well.  */
2209       tree clone;
2210       FOR_EACH_CLONE (clone, decl)
2211         mark_needed (clone);
2212     }
2213   else if (VAR_P (decl))
2214     {
2215       varpool_node *node = varpool_node::get_create (decl);
2216       /* C++ frontend use mark_decl_references to force COMDAT variables
2217          to be output that might appear dead otherwise.  */
2218       node->forced_by_abi = true;
2219     }
2220 }
2221
2222 /* DECL is either a FUNCTION_DECL or a VAR_DECL.  This function
2223    returns true if a definition of this entity should be provided in
2224    this object file.  Callers use this function to determine whether
2225    or not to let the back end know that a definition of DECL is
2226    available in this translation unit.  */
2227
2228 bool
2229 decl_needed_p (tree decl)
2230 {
2231   gcc_assert (VAR_OR_FUNCTION_DECL_P (decl));
2232   /* This function should only be called at the end of the translation
2233      unit.  We cannot be sure of whether or not something will be
2234      COMDAT until that point.  */
2235   gcc_assert (at_eof);
2236
2237   /* All entities with external linkage that are not COMDAT/EXTERN should be
2238      emitted; they may be referred to from other object files.  */
2239   if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_REALLY_EXTERN (decl))
2240     return true;
2241
2242   /* Functions marked "dllexport" must be emitted so that they are
2243      visible to other DLLs.  */
2244   if (flag_keep_inline_dllexport
2245       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
2246     return true;
2247
2248   /* When not optimizing, do not bother to produce definitions for extern
2249      symbols.  */
2250   if (DECL_REALLY_EXTERN (decl)
2251       && ((TREE_CODE (decl) != FUNCTION_DECL
2252            && !optimize)
2253           || (TREE_CODE (decl) == FUNCTION_DECL
2254               && !opt_for_fn (decl, optimize)))
2255       && !lookup_attribute ("always_inline", decl))
2256     return false;
2257
2258   /* If this entity was used, let the back end see it; it will decide
2259      whether or not to emit it into the object file.  */
2260   if (TREE_USED (decl))
2261     return true;
2262
2263   /* Virtual functions might be needed for devirtualization.  */
2264   if (flag_devirtualize
2265       && TREE_CODE (decl) == FUNCTION_DECL
2266       && DECL_VIRTUAL_P (decl))
2267     return true;
2268
2269   /* Otherwise, DECL does not need to be emitted -- yet.  A subsequent
2270      reference to DECL might cause it to be emitted later.  */
2271   return false;
2272 }
2273
2274 /* If necessary, write out the vtables for the dynamic class CTYPE.
2275    Returns true if any vtables were emitted.  */
2276
2277 static bool
2278 maybe_emit_vtables (tree ctype, vec<tree> &consteval_vtables)
2279 {
2280   tree vtbl;
2281   tree primary_vtbl;
2282   int needed = 0;
2283   varpool_node *current = NULL, *last = NULL;
2284
2285   /* If the vtables for this class have already been emitted there is
2286      nothing more to do.  */
2287   primary_vtbl = CLASSTYPE_VTABLES (ctype);
2288   if (var_finalized_p (primary_vtbl))
2289     return false;
2290   /* Ignore dummy vtables made by get_vtable_decl.  */
2291   if (TREE_TYPE (primary_vtbl) == void_type_node)
2292     return false;
2293
2294   /* On some targets, we cannot determine the key method until the end
2295      of the translation unit -- which is when this function is
2296      called.  */
2297   if (!targetm.cxx.key_method_may_be_inline ())
2298     determine_key_method (ctype);
2299
2300   /* See if any of the vtables are needed.  */
2301   for (vtbl = CLASSTYPE_VTABLES (ctype); vtbl; vtbl = DECL_CHAIN (vtbl))
2302     {
2303       import_export_decl (vtbl);
2304       if (DECL_NOT_REALLY_EXTERN (vtbl) && decl_needed_p (vtbl))
2305         needed = 1;
2306     }
2307   if (!needed)
2308     {
2309       /* If the references to this class' vtables are optimized away,
2310          still emit the appropriate debugging information.  See
2311          dfs_debug_mark.  */
2312       if (DECL_COMDAT (primary_vtbl)
2313           && CLASSTYPE_DEBUG_REQUESTED (ctype))
2314         note_debug_info_needed (ctype);
2315       return false;
2316     }
2317
2318   /* The ABI requires that we emit all of the vtables if we emit any
2319      of them.  */
2320   for (vtbl = CLASSTYPE_VTABLES (ctype); vtbl; vtbl = DECL_CHAIN (vtbl))
2321     {
2322       /* Mark entities references from the virtual table as used.  */
2323       mark_vtable_entries (vtbl, consteval_vtables);
2324
2325       if (TREE_TYPE (DECL_INITIAL (vtbl)) == 0)
2326         {
2327           vec<tree, va_gc> *cleanups = NULL;
2328           tree expr = store_init_value (vtbl, DECL_INITIAL (vtbl), &cleanups,
2329                                         LOOKUP_NORMAL);
2330
2331           /* It had better be all done at compile-time.  */
2332           gcc_assert (!expr && !cleanups);
2333         }
2334
2335       /* Write it out.  */
2336       DECL_EXTERNAL (vtbl) = 0;
2337       rest_of_decl_compilation (vtbl, 1, 1);
2338
2339       /* Because we're only doing syntax-checking, we'll never end up
2340          actually marking the variable as written.  */
2341       if (flag_syntax_only)
2342         TREE_ASM_WRITTEN (vtbl) = 1;
2343       else if (DECL_ONE_ONLY (vtbl))
2344         {
2345           current = varpool_node::get_create (vtbl);
2346           if (last)
2347             current->add_to_same_comdat_group (last);
2348           last = current;
2349         }
2350     }
2351
2352   /* For abstract classes, the destructor has been removed from the
2353      vtable (in class.c's build_vtbl_initializer).  For a compiler-
2354      generated destructor, it hence might not have been generated in
2355      this translation unit - and with '#pragma interface' it might
2356      never get generated.  */
2357   if (CLASSTYPE_PURE_VIRTUALS (ctype)
2358       && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype)
2359       && !CLASSTYPE_LAZY_DESTRUCTOR (ctype)
2360       && DECL_DEFAULTED_IN_CLASS_P (CLASSTYPE_DESTRUCTOR (ctype)))
2361     note_vague_linkage_fn (CLASSTYPE_DESTRUCTOR (ctype));
2362
2363   /* Since we're writing out the vtable here, also write the debug
2364      info.  */
2365   note_debug_info_needed (ctype);
2366
2367   return true;
2368 }
2369
2370 /* A special return value from type_visibility meaning internal
2371    linkage.  */
2372
2373 enum { VISIBILITY_ANON = VISIBILITY_INTERNAL+1 };
2374
2375 static int expr_visibility (tree);
2376 static int type_visibility (tree);
2377
2378 /* walk_tree helper function for type_visibility.  */
2379
2380 static tree
2381 min_vis_r (tree *tp, int *walk_subtrees, void *data)
2382 {
2383   int *vis_p = (int *)data;
2384   int this_vis = VISIBILITY_DEFAULT;
2385   if (! TYPE_P (*tp))
2386     *walk_subtrees = 0;
2387   else if (OVERLOAD_TYPE_P (*tp)
2388            && !TREE_PUBLIC (TYPE_MAIN_DECL (*tp)))
2389     {
2390       this_vis = VISIBILITY_ANON;
2391       *walk_subtrees = 0;
2392     }
2393   else if (CLASS_TYPE_P (*tp))
2394     {
2395       this_vis = CLASSTYPE_VISIBILITY (*tp);
2396       *walk_subtrees = 0;
2397     }
2398   else if (TREE_CODE (*tp) == ARRAY_TYPE
2399            && uses_template_parms (TYPE_DOMAIN (*tp)))
2400     this_vis = expr_visibility (TYPE_MAX_VALUE (TYPE_DOMAIN (*tp)));
2401
2402   if (this_vis > *vis_p)
2403     *vis_p = this_vis;
2404
2405   /* Tell cp_walk_subtrees to look through typedefs.  */
2406   if (*walk_subtrees == 1)
2407     *walk_subtrees = 2;
2408
2409   return NULL;
2410 }
2411
2412 /* walk_tree helper function for expr_visibility.  */
2413
2414 static tree
2415 min_vis_expr_r (tree *tp, int */*walk_subtrees*/, void *data)
2416 {
2417   int *vis_p = (int *)data;
2418   int tpvis = VISIBILITY_DEFAULT;
2419
2420   switch (TREE_CODE (*tp))
2421     {
2422     case CAST_EXPR:
2423     case IMPLICIT_CONV_EXPR:
2424     case STATIC_CAST_EXPR:
2425     case REINTERPRET_CAST_EXPR:
2426     case CONST_CAST_EXPR:
2427     case DYNAMIC_CAST_EXPR:
2428     case NEW_EXPR:
2429     case CONSTRUCTOR:
2430     case LAMBDA_EXPR:
2431       tpvis = type_visibility (TREE_TYPE (*tp));
2432       break;
2433
2434     case VAR_DECL:
2435     case FUNCTION_DECL:
2436       if (! TREE_PUBLIC (*tp))
2437         tpvis = VISIBILITY_ANON;
2438       else
2439         tpvis = DECL_VISIBILITY (*tp);
2440       break;
2441
2442     default:
2443       break;
2444     }
2445
2446   if (tpvis > *vis_p)
2447     *vis_p = tpvis;
2448
2449   return NULL_TREE;
2450 }
2451
2452 /* Returns the visibility of TYPE, which is the minimum visibility of its
2453    component types.  */
2454
2455 static int
2456 type_visibility (tree type)
2457 {
2458   int vis = VISIBILITY_DEFAULT;
2459   cp_walk_tree_without_duplicates (&type, min_vis_r, &vis);
2460   return vis;
2461 }
2462
2463 /* Returns the visibility of an expression EXPR that appears in the signature
2464    of a function template, which is the minimum visibility of names that appear
2465    in its mangling.  */
2466
2467 static int
2468 expr_visibility (tree expr)
2469 {
2470   int vis = VISIBILITY_DEFAULT;
2471   cp_walk_tree_without_duplicates (&expr, min_vis_expr_r, &vis);
2472   return vis;
2473 }
2474
2475 /* Limit the visibility of DECL to VISIBILITY, if not explicitly
2476    specified (or if VISIBILITY is static).  If TMPL is true, this
2477    constraint is for a template argument, and takes precedence
2478    over explicitly-specified visibility on the template.  */
2479
2480 static void
2481 constrain_visibility (tree decl, int visibility, bool tmpl)
2482 {
2483   if (visibility == VISIBILITY_ANON)
2484     {
2485       /* extern "C" declarations aren't affected by the anonymous
2486          namespace.  */
2487       if (!DECL_EXTERN_C_P (decl))
2488         {
2489           TREE_PUBLIC (decl) = 0;
2490           DECL_WEAK (decl) = 0;
2491           DECL_COMMON (decl) = 0;
2492           DECL_COMDAT (decl) = false;
2493           if (VAR_OR_FUNCTION_DECL_P (decl))
2494             {
2495               struct symtab_node *snode = symtab_node::get (decl);
2496
2497               if (snode)
2498                 snode->set_comdat_group (NULL);
2499             }
2500           DECL_INTERFACE_KNOWN (decl) = 1;
2501           if (DECL_LANG_SPECIFIC (decl))
2502             DECL_NOT_REALLY_EXTERN (decl) = 1;
2503         }
2504     }
2505   else if (visibility > DECL_VISIBILITY (decl)
2506            && (tmpl || !DECL_VISIBILITY_SPECIFIED (decl)))
2507     {
2508       DECL_VISIBILITY (decl) = (enum symbol_visibility) visibility;
2509       /* This visibility was not specified.  */
2510       DECL_VISIBILITY_SPECIFIED (decl) = false;
2511     }
2512 }
2513
2514 /* Constrain the visibility of DECL based on the visibility of its template
2515    arguments.  */
2516
2517 static void
2518 constrain_visibility_for_template (tree decl, tree targs)
2519 {
2520   /* If this is a template instantiation, check the innermost
2521      template args for visibility constraints.  The outer template
2522      args are covered by the class check.  */
2523   tree args = INNERMOST_TEMPLATE_ARGS (targs);
2524   int i;
2525   for (i = TREE_VEC_LENGTH (args); i > 0; --i)
2526     {
2527       int vis = 0;
2528
2529       tree arg = TREE_VEC_ELT (args, i-1);
2530       if (TYPE_P (arg))
2531         vis = type_visibility (arg);
2532       else
2533         vis = expr_visibility (arg);
2534       if (vis)
2535         constrain_visibility (decl, vis, true);
2536     }
2537 }
2538
2539 /* Like c_determine_visibility, but with additional C++-specific
2540    behavior.
2541
2542    Function-scope entities can rely on the function's visibility because
2543    it is set in start_preparsed_function.
2544
2545    Class-scope entities cannot rely on the class's visibility until the end
2546    of the enclosing class definition.
2547
2548    Note that because namespaces have multiple independent definitions,
2549    namespace visibility is handled elsewhere using the #pragma visibility
2550    machinery rather than by decorating the namespace declaration.
2551
2552    The goal is for constraints from the type to give a diagnostic, and
2553    other constraints to be applied silently.  */
2554
2555 void
2556 determine_visibility (tree decl)
2557 {
2558   /* Remember that all decls get VISIBILITY_DEFAULT when built.  */
2559
2560   /* Only relevant for names with external linkage.  */
2561   if (!TREE_PUBLIC (decl))
2562     return;
2563
2564   /* Cloned constructors and destructors get the same visibility as
2565      the underlying function.  That should be set up in
2566      maybe_clone_body.  */
2567   gcc_assert (!DECL_CLONED_FUNCTION_P (decl));
2568
2569   bool orig_visibility_specified = DECL_VISIBILITY_SPECIFIED (decl);
2570   enum symbol_visibility orig_visibility = DECL_VISIBILITY (decl);
2571
2572   /* The decl may be a template instantiation, which could influence
2573      visibilty.  */
2574   tree template_decl = NULL_TREE;
2575   if (TREE_CODE (decl) == TYPE_DECL)
2576     {
2577       if (CLASS_TYPE_P (TREE_TYPE (decl)))
2578         {
2579           if (CLASSTYPE_USE_TEMPLATE (TREE_TYPE (decl)))
2580             template_decl = decl;
2581         }
2582       else if (TYPE_TEMPLATE_INFO (TREE_TYPE (decl)))
2583         template_decl = decl;
2584     }
2585   else if (DECL_LANG_SPECIFIC (decl) && DECL_USE_TEMPLATE (decl))
2586     template_decl = decl;
2587
2588   if (TREE_CODE (decl) == TYPE_DECL
2589       && LAMBDA_TYPE_P (TREE_TYPE (decl))
2590       && CLASSTYPE_LAMBDA_EXPR (TREE_TYPE (decl)) != error_mark_node)
2591     if (tree extra = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl)))
2592       {
2593         /* The lambda's visibility is limited by that of its extra
2594            scope.  */
2595         int vis = 0;
2596         if (TYPE_P (extra))
2597           vis = type_visibility (extra);
2598         else
2599           vis = expr_visibility (extra);
2600         constrain_visibility (decl, vis, false);
2601       }
2602
2603   /* If DECL is a member of a class, visibility specifiers on the
2604      class can influence the visibility of the DECL.  */
2605   tree class_type = NULL_TREE;
2606   if (DECL_CLASS_SCOPE_P (decl))
2607     class_type = DECL_CONTEXT (decl);
2608   else
2609     {
2610       /* Not a class member.  */
2611
2612       /* Virtual tables have DECL_CONTEXT set to their associated class,
2613          so they are automatically handled above.  */
2614       gcc_assert (!VAR_P (decl)
2615                   || !DECL_VTABLE_OR_VTT_P (decl));
2616
2617       if (DECL_FUNCTION_SCOPE_P (decl) && ! DECL_VISIBILITY_SPECIFIED (decl))
2618         {
2619           /* Local statics and classes get the visibility of their
2620              containing function by default, except that
2621              -fvisibility-inlines-hidden doesn't affect them.  */
2622           tree fn = DECL_CONTEXT (decl);
2623           if (DECL_VISIBILITY_SPECIFIED (fn))
2624             {
2625               DECL_VISIBILITY (decl) = DECL_VISIBILITY (fn);
2626               DECL_VISIBILITY_SPECIFIED (decl) =
2627                 DECL_VISIBILITY_SPECIFIED (fn);
2628             }
2629           else
2630             {
2631               if (DECL_CLASS_SCOPE_P (fn))
2632                 determine_visibility_from_class (decl, DECL_CONTEXT (fn));
2633               else if (determine_hidden_inline (fn))
2634                 {
2635                   DECL_VISIBILITY (decl) = default_visibility;
2636                   DECL_VISIBILITY_SPECIFIED (decl) =
2637                     visibility_options.inpragma;
2638                 }
2639               else
2640                 {
2641                   DECL_VISIBILITY (decl) = DECL_VISIBILITY (fn);
2642                   DECL_VISIBILITY_SPECIFIED (decl) =
2643                     DECL_VISIBILITY_SPECIFIED (fn);
2644                 }
2645             }
2646
2647           /* Local classes in templates have CLASSTYPE_USE_TEMPLATE set,
2648              but have no TEMPLATE_INFO, so don't try to check it.  */
2649           template_decl = NULL_TREE;
2650         }
2651       else if (VAR_P (decl) && DECL_TINFO_P (decl)
2652                && flag_visibility_ms_compat)
2653         {
2654           /* Under -fvisibility-ms-compat, types are visible by default,
2655              even though their contents aren't.  */
2656           tree underlying_type = TREE_TYPE (DECL_NAME (decl));
2657           int underlying_vis = type_visibility (underlying_type);
2658           if (underlying_vis == VISIBILITY_ANON
2659               || (CLASS_TYPE_P (underlying_type)
2660                   && CLASSTYPE_VISIBILITY_SPECIFIED (underlying_type)))
2661             constrain_visibility (decl, underlying_vis, false);
2662           else
2663             DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
2664         }
2665       else if (VAR_P (decl) && DECL_TINFO_P (decl))
2666         {
2667           /* tinfo visibility is based on the type it's for.  */
2668           constrain_visibility
2669             (decl, type_visibility (TREE_TYPE (DECL_NAME (decl))), false);
2670
2671           /* Give the target a chance to override the visibility associated
2672              with DECL.  */
2673           if (TREE_PUBLIC (decl)
2674               && !DECL_REALLY_EXTERN (decl)
2675               && CLASS_TYPE_P (TREE_TYPE (DECL_NAME (decl)))
2676               && !CLASSTYPE_VISIBILITY_SPECIFIED (TREE_TYPE (DECL_NAME (decl))))
2677             targetm.cxx.determine_class_data_visibility (decl);
2678         }
2679       else if (template_decl)
2680         /* Template instantiations and specializations get visibility based
2681            on their template unless they override it with an attribute.  */;
2682       else if (! DECL_VISIBILITY_SPECIFIED (decl))
2683         {
2684           if (determine_hidden_inline (decl))
2685             DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
2686           else
2687             {
2688               /* Set default visibility to whatever the user supplied with
2689                  #pragma GCC visibility or a namespace visibility attribute.  */
2690               DECL_VISIBILITY (decl) = default_visibility;
2691               DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
2692             }
2693         }
2694     }
2695
2696   if (template_decl)
2697     {
2698       /* If the specialization doesn't specify visibility, use the
2699          visibility from the template.  */
2700       tree tinfo = get_template_info (template_decl);
2701       tree args = TI_ARGS (tinfo);
2702       tree attribs = (TREE_CODE (decl) == TYPE_DECL
2703                       ? TYPE_ATTRIBUTES (TREE_TYPE (decl))
2704                       : DECL_ATTRIBUTES (decl));
2705       tree attr = lookup_attribute ("visibility", attribs);
2706
2707       if (args != error_mark_node)
2708         {
2709           tree pattern = DECL_TEMPLATE_RESULT (TI_TEMPLATE (tinfo));
2710
2711           if (!DECL_VISIBILITY_SPECIFIED (decl))
2712             {
2713               if (!attr
2714                   && determine_hidden_inline (decl))
2715                 DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
2716               else
2717                 {
2718                   DECL_VISIBILITY (decl) = DECL_VISIBILITY (pattern);
2719                   DECL_VISIBILITY_SPECIFIED (decl)
2720                     = DECL_VISIBILITY_SPECIFIED (pattern);
2721                 }
2722             }
2723
2724           if (args
2725               /* Template argument visibility outweighs #pragma or namespace
2726                  visibility, but not an explicit attribute.  */
2727               && !attr)
2728             {
2729               int depth = TMPL_ARGS_DEPTH (args);
2730               if (DECL_VISIBILITY_SPECIFIED (decl))
2731                 {
2732                   /* A class template member with explicit visibility
2733                      overrides the class visibility, so we need to apply
2734                      all the levels of template args directly.  */
2735                   int i;
2736                   for (i = 1; i <= depth; ++i)
2737                     {
2738                       tree lev = TMPL_ARGS_LEVEL (args, i);
2739                       constrain_visibility_for_template (decl, lev);
2740                     }
2741                 }
2742               else if (PRIMARY_TEMPLATE_P (TI_TEMPLATE (tinfo)))
2743                 /* Limit visibility based on its template arguments.  */
2744                 constrain_visibility_for_template (decl, args);
2745             }
2746         }
2747     }
2748
2749   if (class_type)
2750     determine_visibility_from_class (decl, class_type);
2751
2752   if (decl_anon_ns_mem_p (decl))
2753     /* Names in an anonymous namespace get internal linkage.  */
2754     constrain_visibility (decl, VISIBILITY_ANON, false);
2755   else if (TREE_CODE (decl) != TYPE_DECL)
2756     {
2757       /* Propagate anonymity from type to decl.  */
2758       int tvis = type_visibility (TREE_TYPE (decl));
2759       if (tvis == VISIBILITY_ANON
2760           || ! DECL_VISIBILITY_SPECIFIED (decl))
2761         constrain_visibility (decl, tvis, false);
2762     }
2763   else if (no_linkage_check (TREE_TYPE (decl), /*relaxed_p=*/true))
2764     /* DR 757: A type without linkage shall not be used as the type of a
2765        variable or function with linkage, unless
2766        o the variable or function has extern "C" linkage (7.5 [dcl.link]), or
2767        o the variable or function is not used (3.2 [basic.def.odr]) or is
2768        defined in the same translation unit.
2769
2770        Since non-extern "C" decls need to be defined in the same
2771        translation unit, we can make the type internal.  */
2772     constrain_visibility (decl, VISIBILITY_ANON, false);
2773
2774   /* If visibility changed and DECL already has DECL_RTL, ensure
2775      symbol flags are updated.  */
2776   if ((DECL_VISIBILITY (decl) != orig_visibility
2777        || DECL_VISIBILITY_SPECIFIED (decl) != orig_visibility_specified)
2778       && ((VAR_P (decl) && TREE_STATIC (decl))
2779           || TREE_CODE (decl) == FUNCTION_DECL)
2780       && DECL_RTL_SET_P (decl))
2781     make_decl_rtl (decl);
2782 }
2783
2784 /* By default, static data members and function members receive
2785    the visibility of their containing class.  */
2786
2787 static void
2788 determine_visibility_from_class (tree decl, tree class_type)
2789 {
2790   if (DECL_VISIBILITY_SPECIFIED (decl))
2791     return;
2792
2793   if (determine_hidden_inline (decl))
2794     DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
2795   else
2796     {
2797       /* Default to the class visibility.  */
2798       DECL_VISIBILITY (decl) = CLASSTYPE_VISIBILITY (class_type);
2799       DECL_VISIBILITY_SPECIFIED (decl)
2800         = CLASSTYPE_VISIBILITY_SPECIFIED (class_type);
2801     }
2802
2803   /* Give the target a chance to override the visibility associated
2804      with DECL.  */
2805   if (VAR_P (decl)
2806       && TREE_PUBLIC (decl)
2807       && (DECL_TINFO_P (decl) || DECL_VTABLE_OR_VTT_P (decl))
2808       && !DECL_REALLY_EXTERN (decl)
2809       && !CLASSTYPE_VISIBILITY_SPECIFIED (class_type))
2810     targetm.cxx.determine_class_data_visibility (decl);
2811 }
2812
2813 /* Returns true iff DECL is an inline that should get hidden visibility
2814    because of -fvisibility-inlines-hidden.  */
2815
2816 static bool
2817 determine_hidden_inline (tree decl)
2818 {
2819   return (visibility_options.inlines_hidden
2820           /* Don't do this for inline templates; specializations might not be
2821              inline, and we don't want them to inherit the hidden
2822              visibility.  We'll set it here for all inline instantiations.  */
2823           && !processing_template_decl
2824           && TREE_CODE (decl) == FUNCTION_DECL
2825           && DECL_DECLARED_INLINE_P (decl)
2826           && (! DECL_LANG_SPECIFIC (decl)
2827               || ! DECL_EXPLICIT_INSTANTIATION (decl)));
2828 }
2829
2830 /* Constrain the visibility of a class TYPE based on the visibility of its
2831    field types.  Warn if any fields require lesser visibility.  */
2832
2833 void
2834 constrain_class_visibility (tree type)
2835 {
2836   tree binfo;
2837   tree t;
2838   int i;
2839
2840   int vis = type_visibility (type);
2841
2842   if (vis == VISIBILITY_ANON
2843       || DECL_IN_SYSTEM_HEADER (TYPE_MAIN_DECL (type)))
2844     return;
2845
2846   /* Don't warn about visibility if the class has explicit visibility.  */
2847   if (CLASSTYPE_VISIBILITY_SPECIFIED (type))
2848     vis = VISIBILITY_INTERNAL;
2849
2850   for (t = TYPE_FIELDS (type); t; t = DECL_CHAIN (t))
2851     if (TREE_CODE (t) == FIELD_DECL && TREE_TYPE (t) != error_mark_node
2852         && !DECL_ARTIFICIAL (t))
2853       {
2854         tree ftype = strip_pointer_or_array_types (TREE_TYPE (t));
2855         int subvis = type_visibility (ftype);
2856
2857         if (subvis == VISIBILITY_ANON)
2858           {
2859             if (!in_main_input_context())
2860               {
2861                 tree nlt = no_linkage_check (ftype, /*relaxed_p=*/false);
2862                 if (nlt)
2863                   {
2864                     if (same_type_p (TREE_TYPE (t), nlt))
2865                       warning (OPT_Wsubobject_linkage, "\
2866 %qT has a field %qD whose type has no linkage",
2867                                type, t);
2868                     else
2869                       warning (OPT_Wsubobject_linkage, "\
2870 %qT has a field %qD whose type depends on the type %qT which has no linkage",
2871                                type, t, nlt);
2872                   }
2873                 else
2874                   warning (OPT_Wsubobject_linkage, "\
2875 %qT has a field %qD whose type uses the anonymous namespace",
2876                            type, t);
2877               }
2878           }
2879         else if (MAYBE_CLASS_TYPE_P (ftype)
2880                  && vis < VISIBILITY_HIDDEN
2881                  && subvis >= VISIBILITY_HIDDEN)
2882           warning (OPT_Wattributes, "\
2883 %qT declared with greater visibility than the type of its field %qD",
2884                    type, t);
2885       }
2886
2887   binfo = TYPE_BINFO (type);
2888   for (i = 0; BINFO_BASE_ITERATE (binfo, i, t); ++i)
2889     {
2890       int subvis = type_visibility (TREE_TYPE (t));
2891
2892       if (subvis == VISIBILITY_ANON)
2893         {
2894           if (!in_main_input_context())
2895             {
2896               tree nlt = no_linkage_check (TREE_TYPE (t), /*relaxed_p=*/false);
2897               if (nlt)
2898                 {
2899                   if (same_type_p (TREE_TYPE (t), nlt))
2900                     warning (OPT_Wsubobject_linkage, "\
2901 %qT has a base %qT whose type has no linkage",
2902                              type, TREE_TYPE (t));
2903                   else
2904                     warning (OPT_Wsubobject_linkage, "\
2905 %qT has a base %qT whose type depends on the type %qT which has no linkage",
2906                              type, TREE_TYPE (t), nlt);
2907                 }
2908               else
2909                 warning (OPT_Wsubobject_linkage, "\
2910 %qT has a base %qT whose type uses the anonymous namespace",
2911                          type, TREE_TYPE (t));
2912             }
2913         }
2914       else if (vis < VISIBILITY_HIDDEN
2915                && subvis >= VISIBILITY_HIDDEN)
2916         warning (OPT_Wattributes, "\
2917 %qT declared with greater visibility than its base %qT",
2918                  type, TREE_TYPE (t));
2919     }
2920 }
2921
2922 /* Functions for adjusting the visibility of a tagged type and its nested
2923    types and declarations when it gets a name for linkage purposes from a
2924    typedef.  */
2925 // FIXME: It is now a DR for such a class type to contain anything
2926 // other than C.  So at minium most of this can probably be deleted.
2927
2928 /* First reset the visibility of all the types.  */
2929
2930 static void
2931 reset_type_linkage_1 (tree type)
2932 {
2933   set_linkage_according_to_type (type, TYPE_MAIN_DECL (type));
2934   if (CLASS_TYPE_P (type))
2935     for (tree member = TYPE_FIELDS (type); member; member = DECL_CHAIN (member))
2936       if (DECL_IMPLICIT_TYPEDEF_P (member))
2937         reset_type_linkage_1 (TREE_TYPE (member));
2938 }
2939
2940 /* Then reset the visibility of any static data members or member
2941    functions that use those types.  */
2942
2943 static void
2944 reset_decl_linkage (tree decl)
2945 {
2946   if (TREE_PUBLIC (decl))
2947     return;
2948   if (DECL_CLONED_FUNCTION_P (decl))
2949     return;
2950   TREE_PUBLIC (decl) = true;
2951   DECL_INTERFACE_KNOWN (decl) = false;
2952   determine_visibility (decl);
2953   tentative_decl_linkage (decl);
2954 }
2955
2956 void
2957 reset_type_linkage (tree type)
2958 {
2959   reset_type_linkage_1 (type);
2960   if (CLASS_TYPE_P (type))
2961     {
2962       if (tree vt = CLASSTYPE_VTABLES (type))
2963         {
2964           tree name = mangle_vtbl_for_type (type);
2965           DECL_NAME (vt) = name;
2966           SET_DECL_ASSEMBLER_NAME (vt, name);
2967           reset_decl_linkage (vt);
2968         }
2969       if (tree ti = CLASSTYPE_TYPEINFO_VAR (type))
2970         {
2971           tree name = mangle_typeinfo_for_type (type);
2972           DECL_NAME (ti) = name;
2973           SET_DECL_ASSEMBLER_NAME (ti, name);
2974           TREE_TYPE (name) = type;
2975           reset_decl_linkage (ti);
2976         }
2977       for (tree m = TYPE_FIELDS (type); m; m = DECL_CHAIN (m))
2978         {
2979           tree mem = STRIP_TEMPLATE (m);
2980           if (TREE_CODE (mem) == VAR_DECL || TREE_CODE (mem) == FUNCTION_DECL)
2981             reset_decl_linkage (mem);
2982           else if (DECL_IMPLICIT_TYPEDEF_P (mem))
2983             reset_type_linkage (TREE_TYPE (mem));
2984         }
2985     }
2986 }
2987
2988 /* Set up our initial idea of what the linkage of DECL should be.  */
2989
2990 void
2991 tentative_decl_linkage (tree decl)
2992 {
2993   if (DECL_INTERFACE_KNOWN (decl))
2994     /* We've already made a decision as to how this function will
2995        be handled.  */;
2996   else if (vague_linkage_p (decl))
2997     {
2998       if (TREE_CODE (decl) == FUNCTION_DECL
2999           && decl_defined_p (decl))
3000         {
3001           DECL_EXTERNAL (decl) = 1;
3002           DECL_NOT_REALLY_EXTERN (decl) = 1;
3003           note_vague_linkage_fn (decl);
3004           /* A non-template inline function with external linkage will
3005              always be COMDAT.  As we must eventually determine the
3006              linkage of all functions, and as that causes writes to
3007              the data mapped in from the PCH file, it's advantageous
3008              to mark the functions at this point.  */
3009           if (DECL_DECLARED_INLINE_P (decl)
3010               && (!DECL_IMPLICIT_INSTANTIATION (decl)
3011                   || DECL_DEFAULTED_FN (decl)))
3012             {
3013               /* This function must have external linkage, as
3014                  otherwise DECL_INTERFACE_KNOWN would have been
3015                  set.  */
3016               gcc_assert (TREE_PUBLIC (decl));
3017               comdat_linkage (decl);
3018               DECL_INTERFACE_KNOWN (decl) = 1;
3019             }
3020         }
3021       else if (VAR_P (decl))
3022         maybe_commonize_var (decl);
3023     }
3024 }
3025
3026 /* DECL is a FUNCTION_DECL or VAR_DECL.  If the object file linkage
3027    for DECL has not already been determined, do so now by setting
3028    DECL_EXTERNAL, DECL_COMDAT and other related flags.  Until this
3029    function is called entities with vague linkage whose definitions
3030    are available must have TREE_PUBLIC set.
3031
3032    If this function decides to place DECL in COMDAT, it will set
3033    appropriate flags -- but will not clear DECL_EXTERNAL.  It is up to
3034    the caller to decide whether or not to clear DECL_EXTERNAL.  Some
3035    callers defer that decision until it is clear that DECL is actually
3036    required.  */
3037
3038 void
3039 import_export_decl (tree decl)
3040 {
3041   bool comdat_p;
3042   bool import_p;
3043   tree class_type = NULL_TREE;
3044
3045   if (DECL_INTERFACE_KNOWN (decl))
3046     return;
3047
3048   /* We cannot determine what linkage to give to an entity with vague
3049      linkage until the end of the file.  For example, a virtual table
3050      for a class will be defined if and only if the key method is
3051      defined in this translation unit.  */
3052   gcc_assert (at_eof);
3053   /* Object file linkage for explicit instantiations is handled in
3054      mark_decl_instantiated.  For static variables in functions with
3055      vague linkage, maybe_commonize_var is used.
3056
3057      Therefore, the only declarations that should be provided to this
3058      function are those with external linkage that are:
3059
3060      * implicit instantiations of function templates
3061
3062      * inline function
3063
3064      * implicit instantiations of static data members of class
3065        templates
3066
3067      * virtual tables
3068
3069      * typeinfo objects
3070
3071      Furthermore, all entities that reach this point must have a
3072      definition available in this translation unit.
3073
3074      The following assertions check these conditions.  */
3075   gcc_assert (VAR_OR_FUNCTION_DECL_P (decl));
3076   /* Any code that creates entities with TREE_PUBLIC cleared should
3077      also set DECL_INTERFACE_KNOWN.  */
3078   gcc_assert (TREE_PUBLIC (decl));
3079   if (TREE_CODE (decl) == FUNCTION_DECL)
3080     gcc_assert (DECL_IMPLICIT_INSTANTIATION (decl)
3081                 || DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (decl)
3082                 || DECL_DECLARED_INLINE_P (decl));
3083   else
3084     gcc_assert (DECL_IMPLICIT_INSTANTIATION (decl)
3085                 || DECL_VTABLE_OR_VTT_P (decl)
3086                 || DECL_TINFO_P (decl));
3087   /* Check that a definition of DECL is available in this translation
3088      unit.  */
3089   gcc_assert (!DECL_REALLY_EXTERN (decl));
3090
3091   /* Assume that DECL will not have COMDAT linkage.  */
3092   comdat_p = false;
3093   /* Assume that DECL will not be imported into this translation
3094      unit.  */
3095   import_p = false;
3096
3097   if (VAR_P (decl) && DECL_VTABLE_OR_VTT_P (decl))
3098     {
3099       class_type = DECL_CONTEXT (decl);
3100       import_export_class (class_type);
3101       if (CLASSTYPE_INTERFACE_KNOWN (class_type)
3102           && CLASSTYPE_INTERFACE_ONLY (class_type))
3103         import_p = true;
3104       else if ((!flag_weak || TARGET_WEAK_NOT_IN_ARCHIVE_TOC)
3105                && !CLASSTYPE_USE_TEMPLATE (class_type)
3106                && CLASSTYPE_KEY_METHOD (class_type)
3107                && !DECL_DECLARED_INLINE_P (CLASSTYPE_KEY_METHOD (class_type)))
3108         /* The ABI requires that all virtual tables be emitted with
3109            COMDAT linkage.  However, on systems where COMDAT symbols
3110            don't show up in the table of contents for a static
3111            archive, or on systems without weak symbols (where we
3112            approximate COMDAT linkage by using internal linkage), the
3113            linker will report errors about undefined symbols because
3114            it will not see the virtual table definition.  Therefore,
3115            in the case that we know that the virtual table will be
3116            emitted in only one translation unit, we make the virtual
3117            table an ordinary definition with external linkage.  */
3118         DECL_EXTERNAL (decl) = 0;
3119       else if (CLASSTYPE_INTERFACE_KNOWN (class_type))
3120         {
3121           /* CLASS_TYPE is being exported from this translation unit,
3122              so DECL should be defined here.  */
3123           if (!flag_weak && CLASSTYPE_EXPLICIT_INSTANTIATION (class_type))
3124             /* If a class is declared in a header with the "extern
3125                template" extension, then it will not be instantiated,
3126                even in translation units that would normally require
3127                it.  Often such classes are explicitly instantiated in
3128                one translation unit.  Therefore, the explicit
3129                instantiation must be made visible to other translation
3130                units.  */
3131             DECL_EXTERNAL (decl) = 0;
3132           else
3133             {
3134               /* The generic C++ ABI says that class data is always
3135                  COMDAT, even if there is a key function.  Some
3136                  variants (e.g., the ARM EABI) says that class data
3137                  only has COMDAT linkage if the class data might be
3138                  emitted in more than one translation unit.  When the
3139                  key method can be inline and is inline, we still have
3140                  to arrange for comdat even though
3141                  class_data_always_comdat is false.  */
3142               if (!CLASSTYPE_KEY_METHOD (class_type)
3143                   || DECL_DECLARED_INLINE_P (CLASSTYPE_KEY_METHOD (class_type))
3144                   || targetm.cxx.class_data_always_comdat ())
3145                 {
3146                   /* The ABI requires COMDAT linkage.  Normally, we
3147                      only emit COMDAT things when they are needed;
3148                      make sure that we realize that this entity is
3149                      indeed needed.  */
3150                   comdat_p = true;
3151                   mark_needed (decl);
3152                 }
3153             }
3154         }
3155       else if (!flag_implicit_templates
3156                && CLASSTYPE_IMPLICIT_INSTANTIATION (class_type))
3157         import_p = true;
3158       else
3159         comdat_p = true;
3160     }
3161   else if (VAR_P (decl) && DECL_TINFO_P (decl))
3162     {
3163       tree type = TREE_TYPE (DECL_NAME (decl));
3164       if (CLASS_TYPE_P (type))
3165         {
3166           class_type = type;
3167           import_export_class (type);
3168           if (CLASSTYPE_INTERFACE_KNOWN (type)
3169               && TYPE_POLYMORPHIC_P (type)
3170               && CLASSTYPE_INTERFACE_ONLY (type)
3171               /* If -fno-rtti was specified, then we cannot be sure
3172                  that RTTI information will be emitted with the
3173                  virtual table of the class, so we must emit it
3174                  wherever it is used.  */
3175               && flag_rtti)
3176             import_p = true;
3177           else
3178             {
3179               if (CLASSTYPE_INTERFACE_KNOWN (type)
3180                   && !CLASSTYPE_INTERFACE_ONLY (type))
3181                 {
3182                   comdat_p = (targetm.cxx.class_data_always_comdat ()
3183                               || (CLASSTYPE_KEY_METHOD (type)
3184                                   && DECL_DECLARED_INLINE_P (CLASSTYPE_KEY_METHOD (type))));
3185                   mark_needed (decl);
3186                   if (!flag_weak)
3187                     {
3188                       comdat_p = false;
3189                       DECL_EXTERNAL (decl) = 0;
3190                     }
3191                 }
3192               else
3193                 comdat_p = true;
3194             }
3195         }
3196       else
3197         comdat_p = true;
3198     }
3199   else if (DECL_TEMPLOID_INSTANTIATION (decl))
3200     {
3201       /* DECL is an implicit instantiation of a function or static
3202          data member.  */
3203       if (flag_implicit_templates
3204           || (flag_implicit_inline_templates
3205               && TREE_CODE (decl) == FUNCTION_DECL
3206               && DECL_DECLARED_INLINE_P (decl)))
3207         comdat_p = true;
3208       else
3209         /* If we are not implicitly generating templates, then mark
3210            this entity as undefined in this translation unit.  */
3211         import_p = true;
3212     }
3213   else if (DECL_FUNCTION_MEMBER_P (decl))
3214     {
3215       if (!DECL_DECLARED_INLINE_P (decl))
3216         {
3217           tree ctype = DECL_CONTEXT (decl);
3218           import_export_class (ctype);
3219           if (CLASSTYPE_INTERFACE_KNOWN (ctype))
3220             {
3221               DECL_NOT_REALLY_EXTERN (decl)
3222                 = ! (CLASSTYPE_INTERFACE_ONLY (ctype)
3223                      || (DECL_DECLARED_INLINE_P (decl)
3224                          && ! flag_implement_inlines
3225                          && !DECL_VINDEX (decl)));
3226
3227               if (!DECL_NOT_REALLY_EXTERN (decl))
3228                 DECL_EXTERNAL (decl) = 1;
3229
3230               /* Always make artificials weak.  */
3231               if (DECL_ARTIFICIAL (decl) && flag_weak)
3232                 comdat_p = true;
3233               else
3234                 maybe_make_one_only (decl);
3235             }
3236         }
3237       else
3238         comdat_p = true;
3239     }
3240   else
3241     comdat_p = true;
3242
3243   if (import_p)
3244     {
3245       /* If we are importing DECL into this translation unit, mark is
3246          an undefined here.  */
3247       DECL_EXTERNAL (decl) = 1;
3248       DECL_NOT_REALLY_EXTERN (decl) = 0;
3249     }
3250   else if (comdat_p)
3251     {
3252       /* If we decided to put DECL in COMDAT, mark it accordingly at
3253          this point.  */
3254       comdat_linkage (decl);
3255     }
3256
3257   DECL_INTERFACE_KNOWN (decl) = 1;
3258 }
3259
3260 /* Return an expression that performs the destruction of DECL, which
3261    must be a VAR_DECL whose type has a non-trivial destructor, or is
3262    an array whose (innermost) elements have a non-trivial destructor.  */
3263
3264 tree
3265 build_cleanup (tree decl)
3266 {
3267   tree clean = cxx_maybe_build_cleanup (decl, tf_warning_or_error);
3268   gcc_assert (clean != NULL_TREE);
3269   return clean;
3270 }
3271
3272 /* GUARD is a helper variable for DECL; make them have the same linkage and
3273    visibility.  */
3274
3275 void
3276 copy_linkage (tree guard, tree decl)
3277 {
3278   TREE_PUBLIC (guard) = TREE_PUBLIC (decl);
3279   TREE_STATIC (guard) = TREE_STATIC (decl);
3280   DECL_COMMON (guard) = DECL_COMMON (decl);
3281   DECL_COMDAT (guard) = DECL_COMDAT (decl);
3282   if (TREE_STATIC (guard))
3283     {
3284       CP_DECL_THREAD_LOCAL_P (guard) = CP_DECL_THREAD_LOCAL_P (decl);
3285       set_decl_tls_model (guard, DECL_TLS_MODEL (decl));
3286       if (DECL_ONE_ONLY (decl))
3287         make_decl_one_only (guard, cxx_comdat_group (guard));
3288       if (TREE_PUBLIC (decl))
3289         DECL_WEAK (guard) = DECL_WEAK (decl);
3290       /* Also check vague_linkage_p, as DECL_WEAK and DECL_ONE_ONLY might not
3291          be set until import_export_decl at EOF.  */
3292       if (vague_linkage_p (decl))
3293         comdat_linkage (guard);
3294       DECL_VISIBILITY (guard) = DECL_VISIBILITY (decl);
3295       DECL_VISIBILITY_SPECIFIED (guard) = DECL_VISIBILITY_SPECIFIED (decl);
3296     }
3297 }
3298
3299 /* Returns the initialization guard variable for the variable DECL,
3300    which has static storage duration.  */
3301
3302 tree
3303 get_guard (tree decl)
3304 {
3305   tree sname = mangle_guard_variable (decl);
3306   tree guard = get_global_binding (sname);
3307   if (! guard)
3308     {
3309       tree guard_type;
3310
3311       /* We use a type that is big enough to contain a mutex as well
3312          as an integer counter.  */
3313       guard_type = targetm.cxx.guard_type ();
3314       guard = build_decl (DECL_SOURCE_LOCATION (decl),
3315                           VAR_DECL, sname, guard_type);
3316
3317       /* The guard should have the same linkage as what it guards.  */
3318       copy_linkage (guard, decl);
3319
3320       DECL_ARTIFICIAL (guard) = 1;
3321       DECL_IGNORED_P (guard) = 1;
3322       TREE_USED (guard) = 1;
3323       pushdecl_top_level_and_finish (guard, NULL_TREE);
3324     }
3325   return guard;
3326 }
3327
3328 /* Returns true if accessing the GUARD atomic is expensive,
3329    i.e. involves a call to __sync_synchronize or similar.
3330    In this case let __cxa_guard_acquire handle the atomics.  */
3331
3332 static bool
3333 is_atomic_expensive_p (machine_mode mode)
3334 {
3335   if (!flag_inline_atomics)
3336     return true;
3337
3338   if (!can_compare_and_swap_p (mode, false) || !can_atomic_load_p (mode))
3339     return true;
3340
3341   return false;
3342 }
3343
3344 /* Return an atomic load of src with the appropriate memory model.  */
3345
3346 static tree
3347 build_atomic_load_type (tree src, HOST_WIDE_INT model, tree type)
3348 {
3349   tree ptr_type = build_pointer_type (type);
3350   tree mem_model = build_int_cst (integer_type_node, model);
3351   tree t, addr, val;
3352   unsigned int size;
3353   int fncode;
3354
3355   size = tree_to_uhwi (TYPE_SIZE_UNIT (type));
3356
3357   fncode = BUILT_IN_ATOMIC_LOAD_N + exact_log2 (size) + 1;
3358   t = builtin_decl_implicit ((enum built_in_function) fncode);
3359
3360   addr = build1 (ADDR_EXPR, ptr_type, src);
3361   val = build_call_expr (t, 2, addr, mem_model);
3362   return val;
3363 }
3364
3365 /* Return those bits of the GUARD variable that should be set when the
3366    guarded entity is actually initialized.  */
3367
3368 static tree
3369 get_guard_bits (tree guard)
3370 {
3371   if (!targetm.cxx.guard_mask_bit ())
3372     {
3373       /* We only set the first byte of the guard, in order to leave room
3374          for a mutex in the high-order bits.  */
3375       guard = build1 (ADDR_EXPR,
3376                       build_pointer_type (TREE_TYPE (guard)),
3377                       guard);
3378       guard = build1 (NOP_EXPR,
3379                       build_pointer_type (char_type_node),
3380                       guard);
3381       guard = build1 (INDIRECT_REF, char_type_node, guard);
3382     }
3383
3384   return guard;
3385 }
3386
3387 /* Return an expression which determines whether or not the GUARD
3388    variable has already been initialized.  */
3389
3390 tree
3391 get_guard_cond (tree guard, bool thread_safe)
3392 {
3393   tree guard_value;
3394
3395   if (!thread_safe)
3396     guard = get_guard_bits (guard);
3397   else
3398     {
3399       tree type = targetm.cxx.guard_mask_bit ()
3400                   ? TREE_TYPE (guard) : char_type_node;
3401
3402       if (is_atomic_expensive_p (TYPE_MODE (type)))
3403         guard = integer_zero_node;
3404       else
3405         guard = build_atomic_load_type (guard, MEMMODEL_ACQUIRE, type);
3406     }
3407
3408   /* Mask off all but the low bit.  */
3409   if (targetm.cxx.guard_mask_bit ())
3410     {
3411       guard_value = integer_one_node;
3412       if (!same_type_p (TREE_TYPE (guard_value), TREE_TYPE (guard)))
3413         guard_value = fold_convert (TREE_TYPE (guard), guard_value);
3414       guard = cp_build_binary_op (input_location,
3415                                   BIT_AND_EXPR, guard, guard_value,
3416                                   tf_warning_or_error);
3417     }
3418
3419   guard_value = integer_zero_node;
3420   if (!same_type_p (TREE_TYPE (guard_value), TREE_TYPE (guard)))
3421     guard_value = fold_convert (TREE_TYPE (guard), guard_value);
3422   return cp_build_binary_op (input_location,
3423                              EQ_EXPR, guard, guard_value,
3424                              tf_warning_or_error);
3425 }
3426
3427 /* Return an expression which sets the GUARD variable, indicating that
3428    the variable being guarded has been initialized.  */
3429
3430 tree
3431 set_guard (tree guard)
3432 {
3433   tree guard_init;
3434
3435   /* Set the GUARD to one.  */
3436   guard = get_guard_bits (guard);
3437   guard_init = integer_one_node;
3438   if (!same_type_p (TREE_TYPE (guard_init), TREE_TYPE (guard)))
3439     guard_init = fold_convert (TREE_TYPE (guard), guard_init);
3440   return cp_build_modify_expr (input_location, guard, NOP_EXPR, guard_init,
3441                                tf_warning_or_error);
3442 }
3443
3444 /* Returns true iff we can tell that VAR does not have a dynamic
3445    initializer.  */
3446
3447 static bool
3448 var_defined_without_dynamic_init (tree var)
3449 {
3450   /* constinit vars are guaranteed to not have dynamic initializer,
3451      but still registering the destructor counts as dynamic initialization.  */
3452   if (DECL_DECLARED_CONSTINIT_P (var)
3453       && COMPLETE_TYPE_P (TREE_TYPE (var))
3454       && !TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (var)))
3455     return true;
3456   /* If it's defined in another TU, we can't tell.  */
3457   if (DECL_EXTERNAL (var))
3458     return false;
3459   /* If it has a non-trivial destructor, registering the destructor
3460      counts as dynamic initialization.  */
3461   if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (var)))
3462     return false;
3463   /* If it's in this TU, its initializer has been processed, unless
3464      it's a case of self-initialization, then DECL_INITIALIZED_P is
3465      false while the initializer is handled by finish_id_expression.  */
3466   if (!DECL_INITIALIZED_P (var))
3467     return false;
3468   /* If it has no initializer or a constant one, it's not dynamic.  */
3469   return (!DECL_NONTRIVIALLY_INITIALIZED_P (var)
3470           || DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (var));
3471 }
3472
3473 /* Returns true iff VAR is a variable that needs uses to be
3474    wrapped for possible dynamic initialization.  */
3475
3476 static bool
3477 var_needs_tls_wrapper (tree var)
3478 {
3479   return (!error_operand_p (var)
3480           && CP_DECL_THREAD_LOCAL_P (var)
3481           && !DECL_GNU_TLS_P (var)
3482           && !DECL_FUNCTION_SCOPE_P (var)
3483           && !var_defined_without_dynamic_init (var));
3484 }
3485
3486 /* Get the FUNCTION_DECL for the shared TLS init function for this
3487    translation unit.  */
3488
3489 static tree
3490 get_local_tls_init_fn (location_t loc)
3491 {
3492   tree sname = get_identifier ("__tls_init");
3493   tree fn = get_global_binding (sname);
3494   if (!fn)
3495     {
3496       fn = build_lang_decl_loc (loc, FUNCTION_DECL, sname,
3497                                 build_function_type (void_type_node,
3498                                                      void_list_node));
3499       SET_DECL_LANGUAGE (fn, lang_c);
3500       TREE_PUBLIC (fn) = false;
3501       DECL_ARTIFICIAL (fn) = true;
3502       mark_used (fn);
3503       set_global_binding (fn);
3504     }
3505   return fn;
3506 }
3507
3508 /* Get a FUNCTION_DECL for the init function for the thread_local
3509    variable VAR.  The init function will be an alias to the function
3510    that initializes all the non-local TLS variables in the translation
3511    unit.  The init function is only used by the wrapper function.  */
3512
3513 static tree
3514 get_tls_init_fn (tree var)
3515 {
3516   /* Only C++11 TLS vars need this init fn.  */
3517   if (!var_needs_tls_wrapper (var))
3518     return NULL_TREE;
3519
3520   /* If -fno-extern-tls-init, assume that we don't need to call
3521      a tls init function for a variable defined in another TU.  */
3522   if (!flag_extern_tls_init && DECL_EXTERNAL (var))
3523     return NULL_TREE;
3524
3525   /* If the variable is internal, or if we can't generate aliases,
3526      call the local init function directly.  */
3527   if (!TREE_PUBLIC (var) || !TARGET_SUPPORTS_ALIASES)
3528     return get_local_tls_init_fn (DECL_SOURCE_LOCATION (var));
3529
3530   tree sname = mangle_tls_init_fn (var);
3531   tree fn = get_global_binding (sname);
3532   if (!fn)
3533     {
3534       fn = build_lang_decl (FUNCTION_DECL, sname,
3535                             build_function_type (void_type_node,
3536                                                  void_list_node));
3537       SET_DECL_LANGUAGE (fn, lang_c);
3538       TREE_PUBLIC (fn) = TREE_PUBLIC (var);
3539       DECL_ARTIFICIAL (fn) = true;
3540       DECL_COMDAT (fn) = DECL_COMDAT (var);
3541       DECL_EXTERNAL (fn) = DECL_EXTERNAL (var);
3542       if (DECL_ONE_ONLY (var))
3543         make_decl_one_only (fn, cxx_comdat_group (fn));
3544       if (TREE_PUBLIC (var))
3545         {
3546           tree obtype = strip_array_types (non_reference (TREE_TYPE (var)));
3547           /* If the variable is defined somewhere else and might have static
3548              initialization, make the init function a weak reference.  */
3549           if ((!TYPE_NEEDS_CONSTRUCTING (obtype)
3550                || TYPE_HAS_CONSTEXPR_CTOR (obtype)
3551                || TYPE_HAS_TRIVIAL_DFLT (obtype))
3552               && TYPE_HAS_TRIVIAL_DESTRUCTOR (obtype)
3553               && DECL_EXTERNAL (var))
3554             declare_weak (fn);
3555           else
3556             DECL_WEAK (fn) = DECL_WEAK (var);
3557         }
3558       DECL_VISIBILITY (fn) = DECL_VISIBILITY (var);
3559       DECL_VISIBILITY_SPECIFIED (fn) = DECL_VISIBILITY_SPECIFIED (var);
3560       DECL_DLLIMPORT_P (fn) = DECL_DLLIMPORT_P (var);
3561       DECL_IGNORED_P (fn) = 1;
3562       mark_used (fn);
3563
3564       DECL_BEFRIENDING_CLASSES (fn) = var;
3565
3566       set_global_binding (fn);
3567     }
3568   return fn;
3569 }
3570
3571 /* Get a FUNCTION_DECL for the init wrapper function for the thread_local
3572    variable VAR.  The wrapper function calls the init function (if any) for
3573    VAR and then returns a reference to VAR.  The wrapper function is used
3574    in place of VAR everywhere VAR is mentioned.  */
3575
3576 static tree
3577 get_tls_wrapper_fn (tree var)
3578 {
3579   /* Only C++11 TLS vars need this wrapper fn.  */
3580   if (!var_needs_tls_wrapper (var))
3581     return NULL_TREE;
3582
3583   tree sname = mangle_tls_wrapper_fn (var);
3584   tree fn = get_global_binding (sname);
3585   if (!fn)
3586     {
3587       /* A named rvalue reference is an lvalue, so the wrapper should
3588          always return an lvalue reference.  */
3589       tree type = non_reference (TREE_TYPE (var));
3590       type = build_reference_type (type);
3591       tree fntype = build_function_type (type, void_list_node);
3592
3593       fn = build_lang_decl_loc (DECL_SOURCE_LOCATION (var),
3594                                 FUNCTION_DECL, sname, fntype);
3595       SET_DECL_LANGUAGE (fn, lang_c);
3596       TREE_PUBLIC (fn) = TREE_PUBLIC (var);
3597       DECL_ARTIFICIAL (fn) = true;
3598       DECL_IGNORED_P (fn) = 1;
3599       /* The wrapper is inline and emitted everywhere var is used.  */
3600       DECL_DECLARED_INLINE_P (fn) = true;
3601       if (TREE_PUBLIC (var))
3602         {
3603           comdat_linkage (fn);
3604 #ifdef HAVE_GAS_HIDDEN
3605           /* Make the wrapper bind locally; there's no reason to share
3606              the wrapper between multiple shared objects.  */
3607           DECL_VISIBILITY (fn) = VISIBILITY_INTERNAL;
3608           DECL_VISIBILITY_SPECIFIED (fn) = true;
3609 #endif
3610         }
3611       if (!TREE_PUBLIC (fn))
3612         DECL_INTERFACE_KNOWN (fn) = true;
3613       mark_used (fn);
3614       note_vague_linkage_fn (fn);
3615
3616 #if 0
3617       /* We want CSE to commonize calls to the wrapper, but marking it as
3618          pure is unsafe since it has side-effects.  I guess we need a new
3619          ECF flag even weaker than ECF_PURE.  FIXME!  */
3620       DECL_PURE_P (fn) = true;
3621 #endif
3622
3623       DECL_BEFRIENDING_CLASSES (fn) = var;
3624
3625       set_global_binding (fn);
3626     }
3627   return fn;
3628 }
3629
3630 /* If EXPR is a thread_local variable that should be wrapped by init
3631    wrapper function, return a call to that function, otherwise return
3632    NULL.  */
3633
3634 tree
3635 maybe_get_tls_wrapper_call (tree expr)
3636 {
3637   if (VAR_P (expr)
3638       && !processing_template_decl
3639       && !cp_unevaluated_operand
3640       && CP_DECL_THREAD_LOCAL_P (expr))
3641     if (tree wrap = get_tls_wrapper_fn (expr))
3642       return build_cxx_call (wrap, 0, NULL, tf_warning_or_error);
3643   return NULL;
3644 }
3645
3646 /* At EOF, generate the definition for the TLS wrapper function FN:
3647
3648    T& var_wrapper() {
3649      if (init_fn) init_fn();
3650      return var;
3651    }  */
3652
3653 static void
3654 generate_tls_wrapper (tree fn)
3655 {
3656   tree var = DECL_BEFRIENDING_CLASSES (fn);
3657
3658   start_preparsed_function (fn, NULL_TREE, SF_DEFAULT | SF_PRE_PARSED);
3659   tree body = begin_function_body ();
3660   /* Only call the init fn if there might be one.  */
3661   if (tree init_fn = get_tls_init_fn (var))
3662     {
3663       tree if_stmt = NULL_TREE;
3664       /* If init_fn is a weakref, make sure it exists before calling.  */
3665       if (lookup_attribute ("weak", DECL_ATTRIBUTES (init_fn)))
3666         {
3667           if_stmt = begin_if_stmt ();
3668           tree addr = cp_build_addr_expr (init_fn, tf_warning_or_error);
3669           tree cond = cp_build_binary_op (DECL_SOURCE_LOCATION (var),
3670                                           NE_EXPR, addr, nullptr_node,
3671                                           tf_warning_or_error);
3672           finish_if_stmt_cond (cond, if_stmt);
3673         }
3674       finish_expr_stmt (build_cxx_call
3675                         (init_fn, 0, NULL, tf_warning_or_error));
3676       if (if_stmt)
3677         {
3678           finish_then_clause (if_stmt);
3679           finish_if_stmt (if_stmt);
3680         }
3681     }
3682   else
3683     /* If there's no initialization, the wrapper is a constant function.  */
3684     TREE_READONLY (fn) = true;
3685   finish_return_stmt (convert_from_reference (var));
3686   finish_function_body (body);
3687   expand_or_defer_fn (finish_function (/*inline_p=*/false));
3688 }
3689
3690 /* Start the process of running a particular set of global constructors
3691    or destructors.  Subroutine of do_[cd]tors.  Also called from
3692    vtv_start_verification_constructor_init_function.  */
3693
3694 static tree
3695 start_objects (int method_type, int initp)
3696 {
3697   /* Make ctor or dtor function.  METHOD_TYPE may be 'I' or 'D'.  */
3698   int module_init = 0;
3699
3700   if (initp == DEFAULT_INIT_PRIORITY && method_type == 'I')
3701     module_init = module_initializer_kind ();
3702
3703   tree name = NULL_TREE;
3704   if (module_init > 0)
3705     name = mangle_module_global_init (0);
3706   else
3707     {
3708       char type[14];
3709
3710       unsigned len = sprintf (type, "sub_%c", method_type);
3711       if (initp != DEFAULT_INIT_PRIORITY)
3712         {
3713           char joiner = '_';
3714 #ifdef JOINER
3715           joiner = JOINER;
3716 #endif
3717           type[len++] = joiner;
3718           sprintf (type + len, "%.5u", initp);
3719         }
3720       name = get_file_function_name (type);
3721     }
3722
3723   tree fntype = build_function_type (void_type_node, void_list_node);
3724   tree fndecl = build_lang_decl (FUNCTION_DECL, name, fntype);
3725   DECL_CONTEXT (fndecl) = FROB_CONTEXT (global_namespace);
3726   if (module_init > 0)
3727     {
3728       SET_DECL_ASSEMBLER_NAME (fndecl, name);
3729       TREE_PUBLIC (fndecl) = true;
3730       determine_visibility (fndecl);
3731     }
3732   else
3733     TREE_PUBLIC (fndecl) = 0;
3734   start_preparsed_function (fndecl, /*attrs=*/NULL_TREE, SF_PRE_PARSED);
3735
3736   /* Mark as artificial because it's not explicitly in the user's
3737      source code.  */
3738   DECL_ARTIFICIAL (current_function_decl) = 1;
3739
3740   /* Mark this declaration as used to avoid spurious warnings.  */
3741   TREE_USED (current_function_decl) = 1;
3742
3743   /* Mark this function as a global constructor or destructor.  */
3744   if (method_type == 'I')
3745     DECL_GLOBAL_CTOR_P (current_function_decl) = 1;
3746   else
3747     DECL_GLOBAL_DTOR_P (current_function_decl) = 1;
3748
3749   tree body = begin_compound_stmt (BCS_FN_BODY);
3750
3751   if (module_init > 0)
3752     {
3753       // 'static bool __in_chrg = false;
3754       // if (__inchrg) return;
3755       // __inchrg = true
3756       tree var = build_lang_decl (VAR_DECL, in_charge_identifier,
3757                                   boolean_type_node);
3758       DECL_CONTEXT (var) = fndecl;
3759       DECL_ARTIFICIAL (var) = true;
3760       TREE_STATIC (var) = true;
3761       pushdecl (var);
3762       cp_finish_decl (var, NULL_TREE, false, NULL_TREE, 0);
3763
3764       tree if_stmt = begin_if_stmt ();
3765       finish_if_stmt_cond (var, if_stmt);
3766       finish_return_stmt (NULL_TREE);
3767       finish_then_clause (if_stmt);
3768       finish_if_stmt (if_stmt);
3769
3770       tree assign = build2 (MODIFY_EXPR, boolean_type_node,
3771                             var, boolean_true_node);
3772       TREE_SIDE_EFFECTS (assign) = true;
3773       finish_expr_stmt (assign);
3774     }
3775
3776   if (module_init)
3777     module_add_import_initializers ();
3778
3779   return body;
3780 }
3781
3782 /* Finish the process of running a particular set of global constructors
3783    or destructors.  Subroutine of do_[cd]tors.  */
3784
3785 static void
3786 finish_objects (int method_type, int initp, tree body)
3787 {
3788   /* Finish up.  */
3789   finish_compound_stmt (body);
3790   tree fn = finish_function (/*inline_p=*/false);
3791
3792   if (method_type == 'I')
3793     {
3794       DECL_STATIC_CONSTRUCTOR (fn) = 1;
3795       decl_init_priority_insert (fn, initp);
3796     }
3797   else
3798     {
3799       DECL_STATIC_DESTRUCTOR (fn) = 1;
3800       decl_fini_priority_insert (fn, initp);
3801     }
3802
3803   expand_or_defer_fn (fn);
3804 }
3805
3806 /* The names of the parameters to the function created to handle
3807    initializations and destructions for objects with static storage
3808    duration.  */
3809 #define INITIALIZE_P_IDENTIFIER "__initialize_p"
3810 #define PRIORITY_IDENTIFIER "__priority"
3811
3812 /* The name of the function we create to handle initializations and
3813    destructions for objects with static storage duration.  */
3814 #define SSDF_IDENTIFIER "__static_initialization_and_destruction"
3815
3816 /* The declaration for the __INITIALIZE_P argument.  */
3817 static GTY(()) tree initialize_p_decl;
3818
3819 /* The declaration for the __PRIORITY argument.  */
3820 static GTY(()) tree priority_decl;
3821
3822 /* The declaration for the static storage duration function.  */
3823 static GTY(()) tree ssdf_decl;
3824
3825 /* All the static storage duration functions created in this
3826    translation unit.  */
3827 static GTY(()) vec<tree, va_gc> *ssdf_decls;
3828
3829 /* A map from priority levels to information about that priority
3830    level.  There may be many such levels, so efficient lookup is
3831    important.  */
3832 static splay_tree priority_info_map;
3833
3834 /* Begins the generation of the function that will handle all
3835    initialization and destruction of objects with static storage
3836    duration.  The function generated takes two parameters of type
3837    `int': __INITIALIZE_P and __PRIORITY.  If __INITIALIZE_P is
3838    nonzero, it performs initializations.  Otherwise, it performs
3839    destructions.  It only performs those initializations or
3840    destructions with the indicated __PRIORITY.  The generated function
3841    returns no value.
3842
3843    It is assumed that this function will only be called once per
3844    translation unit.  */
3845
3846 static tree
3847 start_static_storage_duration_function (unsigned count)
3848 {
3849   tree type;
3850   tree body;
3851   char id[sizeof (SSDF_IDENTIFIER) + 1 /* '\0' */ + 32];
3852
3853   /* Create the identifier for this function.  It will be of the form
3854      SSDF_IDENTIFIER_<number>.  */
3855   sprintf (id, "%s_%u", SSDF_IDENTIFIER, count);
3856
3857   type = build_function_type_list (void_type_node,
3858                                    integer_type_node, integer_type_node,
3859                                    NULL_TREE);
3860
3861   /* Create the FUNCTION_DECL itself.  */
3862   ssdf_decl = build_lang_decl (FUNCTION_DECL,
3863                                get_identifier (id),
3864                                type);
3865   TREE_PUBLIC (ssdf_decl) = 0;
3866   DECL_ARTIFICIAL (ssdf_decl) = 1;
3867
3868   /* Put this function in the list of functions to be called from the
3869      static constructors and destructors.  */
3870   if (!ssdf_decls)
3871     {
3872       vec_alloc (ssdf_decls, 32);
3873
3874       /* Take this opportunity to initialize the map from priority
3875          numbers to information about that priority level.  */
3876       priority_info_map = splay_tree_new (splay_tree_compare_ints,
3877                                           /*delete_key_fn=*/0,
3878                                           /*delete_value_fn=*/
3879                                           splay_tree_delete_pointers);
3880
3881       /* We always need to generate functions for the
3882          DEFAULT_INIT_PRIORITY so enter it now.  That way when we walk
3883          priorities later, we'll be sure to find the
3884          DEFAULT_INIT_PRIORITY.  */
3885       get_priority_info (DEFAULT_INIT_PRIORITY);
3886     }
3887
3888   vec_safe_push (ssdf_decls, ssdf_decl);
3889
3890   /* Create the argument list.  */
3891   initialize_p_decl = cp_build_parm_decl
3892     (ssdf_decl, get_identifier (INITIALIZE_P_IDENTIFIER), integer_type_node);
3893   TREE_USED (initialize_p_decl) = 1;
3894   priority_decl = cp_build_parm_decl
3895     (ssdf_decl, get_identifier (PRIORITY_IDENTIFIER), integer_type_node);
3896   TREE_USED (priority_decl) = 1;
3897
3898   DECL_CHAIN (initialize_p_decl) = priority_decl;
3899   DECL_ARGUMENTS (ssdf_decl) = initialize_p_decl;
3900
3901   /* Put the function in the global scope.  */
3902   pushdecl (ssdf_decl);
3903
3904   /* Start the function itself.  This is equivalent to declaring the
3905      function as:
3906
3907        static void __ssdf (int __initialize_p, init __priority_p);
3908
3909      It is static because we only need to call this function from the
3910      various constructor and destructor functions for this module.  */
3911   start_preparsed_function (ssdf_decl,
3912                             /*attrs=*/NULL_TREE,
3913                             SF_PRE_PARSED);
3914
3915   /* Set up the scope of the outermost block in the function.  */
3916   body = begin_compound_stmt (BCS_FN_BODY);
3917
3918   return body;
3919 }
3920
3921 /* Finish the generation of the function which performs initialization
3922    and destruction of objects with static storage duration.  After
3923    this point, no more such objects can be created.  */
3924
3925 static void
3926 finish_static_storage_duration_function (tree body)
3927 {
3928   /* Close out the function.  */
3929   finish_compound_stmt (body);
3930   expand_or_defer_fn (finish_function (/*inline_p=*/false));
3931 }
3932
3933 /* Return the information about the indicated PRIORITY level.  If no
3934    code to handle this level has yet been generated, generate the
3935    appropriate prologue.  */
3936
3937 static priority_info
3938 get_priority_info (int priority)
3939 {
3940   priority_info pi;
3941   splay_tree_node n;
3942
3943   n = splay_tree_lookup (priority_info_map,
3944                          (splay_tree_key) priority);
3945   if (!n)
3946     {
3947       /* Create a new priority information structure, and insert it
3948          into the map.  */
3949       pi = XNEW (struct priority_info_s);
3950       pi->initializations_p = 0;
3951       pi->destructions_p = 0;
3952       splay_tree_insert (priority_info_map,
3953                          (splay_tree_key) priority,
3954                          (splay_tree_value) pi);
3955     }
3956   else
3957     pi = (priority_info) n->value;
3958
3959   return pi;
3960 }
3961
3962 /* The effective initialization priority of a DECL.  */
3963
3964 #define DECL_EFFECTIVE_INIT_PRIORITY(decl)                                    \
3965         ((!DECL_HAS_INIT_PRIORITY_P (decl) || DECL_INIT_PRIORITY (decl) == 0) \
3966          ? DEFAULT_INIT_PRIORITY : DECL_INIT_PRIORITY (decl))
3967
3968 /* Whether a DECL needs a guard to protect it against multiple
3969    initialization.  */
3970
3971 #define NEEDS_GUARD_P(decl) (TREE_PUBLIC (decl) && (DECL_COMMON (decl)      \
3972                                                     || DECL_ONE_ONLY (decl) \
3973                                                     || DECL_WEAK (decl)))
3974
3975 /* Called from one_static_initialization_or_destruction(),
3976    via walk_tree.
3977    Walks the initializer list of a global variable and looks for
3978    temporary variables (DECL_NAME() == NULL and DECL_ARTIFICIAL != 0)
3979    and that have their DECL_CONTEXT() == NULL.
3980    For each such temporary variable, set their DECL_CONTEXT() to
3981    the current function. This is necessary because otherwise
3982    some optimizers (enabled by -O2 -fprofile-arcs) might crash
3983    when trying to refer to a temporary variable that does not have
3984    it's DECL_CONTECT() properly set.  */
3985 static tree
3986 fix_temporary_vars_context_r (tree *node,
3987                               int  * /*unused*/,
3988                               void * /*unused1*/)
3989 {
3990   gcc_assert (current_function_decl);
3991
3992   if (TREE_CODE (*node) == BIND_EXPR)
3993     {
3994       tree var;
3995
3996       for (var = BIND_EXPR_VARS (*node); var; var = DECL_CHAIN (var))
3997         if (VAR_P (var)
3998           && !DECL_NAME (var)
3999           && DECL_ARTIFICIAL (var)
4000           && !DECL_CONTEXT (var))
4001           DECL_CONTEXT (var) = current_function_decl;
4002     }
4003
4004   return NULL_TREE;
4005 }
4006
4007 /* Set up to handle the initialization or destruction of DECL.  If
4008    INITP is nonzero, we are initializing the variable.  Otherwise, we
4009    are destroying it.  */
4010
4011 static void
4012 one_static_initialization_or_destruction (tree decl, tree init, bool initp)
4013 {
4014   tree guard_if_stmt = NULL_TREE;
4015   tree guard;
4016
4017   /* If we are supposed to destruct and there's a trivial destructor,
4018      nothing has to be done.  */
4019   if (!initp
4020       && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (decl)))
4021     return;
4022
4023   /* Trick the compiler into thinking we are at the file and line
4024      where DECL was declared so that error-messages make sense, and so
4025      that the debugger will show somewhat sensible file and line
4026      information.  */
4027   input_location = DECL_SOURCE_LOCATION (decl);
4028
4029   /* Make sure temporary variables in the initialiser all have
4030      their DECL_CONTEXT() set to a value different from NULL_TREE.
4031      This can happen when global variables initializers are built.
4032      In that case, the DECL_CONTEXT() of the global variables _AND_ of all
4033      the temporary variables that might have been generated in the
4034      accompanying initializers is NULL_TREE, meaning the variables have been
4035      declared in the global namespace.
4036      What we want to do here is to fix that and make sure the DECL_CONTEXT()
4037      of the temporaries are set to the current function decl.  */
4038   cp_walk_tree_without_duplicates (&init,
4039                                    fix_temporary_vars_context_r,
4040                                    NULL);
4041
4042   /* Because of:
4043
4044        [class.access.spec]
4045
4046        Access control for implicit calls to the constructors,
4047        the conversion functions, or the destructor called to
4048        create and destroy a static data member is performed as
4049        if these calls appeared in the scope of the member's
4050        class.
4051
4052      we pretend we are in a static member function of the class of
4053      which the DECL is a member.  */
4054   if (member_p (decl))
4055     {
4056       DECL_CONTEXT (current_function_decl) = DECL_CONTEXT (decl);
4057       DECL_STATIC_FUNCTION_P (current_function_decl) = 1;
4058     }
4059
4060   /* Assume we don't need a guard.  */
4061   guard = NULL_TREE;
4062   /* We need a guard if this is an object with external linkage that
4063      might be initialized in more than one place.  (For example, a
4064      static data member of a template, when the data member requires
4065      construction.)  */
4066   if (NEEDS_GUARD_P (decl))
4067     {
4068       tree guard_cond;
4069
4070       guard = get_guard (decl);
4071
4072       /* When using __cxa_atexit, we just check the GUARD as we would
4073          for a local static.  */
4074       if (flag_use_cxa_atexit)
4075         {
4076           /* When using __cxa_atexit, we never try to destroy
4077              anything from a static destructor.  */
4078           gcc_assert (initp);
4079           guard_cond = get_guard_cond (guard, false);
4080         }
4081       /* If we don't have __cxa_atexit, then we will be running
4082          destructors from .fini sections, or their equivalents.  So,
4083          we need to know how many times we've tried to initialize this
4084          object.  We do initializations only if the GUARD is zero,
4085          i.e., if we are the first to initialize the variable.  We do
4086          destructions only if the GUARD is one, i.e., if we are the
4087          last to destroy the variable.  */
4088       else if (initp)
4089         guard_cond
4090           = cp_build_binary_op (input_location,
4091                                 EQ_EXPR,
4092                                 cp_build_unary_op (PREINCREMENT_EXPR,
4093                                                    guard,
4094                                                    /*noconvert=*/true,
4095                                                    tf_warning_or_error),
4096                                 integer_one_node,
4097                                 tf_warning_or_error);
4098       else
4099         guard_cond
4100           = cp_build_binary_op (input_location,
4101                                 EQ_EXPR,
4102                                 cp_build_unary_op (PREDECREMENT_EXPR,
4103                                                    guard,
4104                                                    /*noconvert=*/true,
4105                                                    tf_warning_or_error),
4106                                 integer_zero_node,
4107                                 tf_warning_or_error);
4108
4109       guard_if_stmt = begin_if_stmt ();
4110       finish_if_stmt_cond (guard_cond, guard_if_stmt);
4111     }
4112
4113
4114   /* If we're using __cxa_atexit, we have not already set the GUARD,
4115      so we must do so now.  */
4116   if (guard && initp && flag_use_cxa_atexit)
4117     finish_expr_stmt (set_guard (guard));
4118
4119   /* Perform the initialization or destruction.  */
4120   if (initp)
4121     {
4122       if (init)
4123         {
4124           finish_expr_stmt (init);
4125           if (sanitize_flags_p (SANITIZE_ADDRESS, decl))
4126             {
4127               varpool_node *vnode = varpool_node::get (decl);
4128               if (vnode)
4129                 vnode->dynamically_initialized = 1;
4130             }
4131         }
4132
4133       /* If we're using __cxa_atexit, register a function that calls the
4134          destructor for the object.  */
4135       if (flag_use_cxa_atexit)
4136         finish_expr_stmt (register_dtor_fn (decl));
4137     }
4138   else
4139     finish_expr_stmt (build_cleanup (decl));
4140
4141   /* Finish the guard if-stmt, if necessary.  */
4142   if (guard)
4143     {
4144       finish_then_clause (guard_if_stmt);
4145       finish_if_stmt (guard_if_stmt);
4146     }
4147
4148   /* Now that we're done with DECL we don't need to pretend to be a
4149      member of its class any longer.  */
4150   DECL_CONTEXT (current_function_decl) = NULL_TREE;
4151   DECL_STATIC_FUNCTION_P (current_function_decl) = 0;
4152 }
4153
4154 /* Generate code to do the initialization or destruction of the decls in VARS,
4155    a TREE_LIST of VAR_DECL with static storage duration.
4156    Whether initialization or destruction is performed is specified by INITP.  */
4157
4158 static void
4159 do_static_initialization_or_destruction (tree vars, bool initp)
4160 {
4161   tree node, init_if_stmt, cond;
4162
4163   /* Build the outer if-stmt to check for initialization or destruction.  */
4164   init_if_stmt = begin_if_stmt ();
4165   cond = initp ? integer_one_node : integer_zero_node;
4166   cond = cp_build_binary_op (input_location,
4167                              EQ_EXPR,
4168                              initialize_p_decl,
4169                              cond,
4170                              tf_warning_or_error);
4171   finish_if_stmt_cond (cond, init_if_stmt);
4172
4173   /* To make sure dynamic construction doesn't access globals from other
4174      compilation units where they might not be yet constructed, for
4175      -fsanitize=address insert __asan_before_dynamic_init call that
4176      prevents access to either all global variables that need construction
4177      in other compilation units, or at least those that haven't been
4178      initialized yet.  Variables that need dynamic construction in
4179      the current compilation unit are kept accessible.  */
4180   if (initp && (flag_sanitize & SANITIZE_ADDRESS))
4181     finish_expr_stmt (asan_dynamic_init_call (/*after_p=*/false));
4182
4183   node = vars;
4184   do {
4185     tree decl = TREE_VALUE (node);
4186     tree priority_if_stmt;
4187     int priority;
4188     priority_info pi;
4189
4190     /* If we don't need a destructor, there's nothing to do.  Avoid
4191        creating a possibly empty if-stmt.  */
4192     if (!initp && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (decl)))
4193       {
4194         node = TREE_CHAIN (node);
4195         continue;
4196       }
4197
4198     /* Remember that we had an initialization or finalization at this
4199        priority.  */
4200     priority = DECL_EFFECTIVE_INIT_PRIORITY (decl);
4201     pi = get_priority_info (priority);
4202     if (initp)
4203       pi->initializations_p = 1;
4204     else
4205       pi->destructions_p = 1;
4206
4207     /* Conditionalize this initialization on being in the right priority
4208        and being initializing/finalizing appropriately.  */
4209     priority_if_stmt = begin_if_stmt ();
4210     cond = cp_build_binary_op (input_location,
4211                                EQ_EXPR,
4212                                priority_decl,
4213                                build_int_cst (NULL_TREE, priority),
4214                                tf_warning_or_error);
4215     finish_if_stmt_cond (cond, priority_if_stmt);
4216
4217     /* Process initializers with same priority.  */
4218     for (; node
4219            && DECL_EFFECTIVE_INIT_PRIORITY (TREE_VALUE (node)) == priority;
4220          node = TREE_CHAIN (node))
4221       /* Do one initialization or destruction.  */
4222       one_static_initialization_or_destruction (TREE_VALUE (node),
4223                                                 TREE_PURPOSE (node), initp);
4224
4225     /* Finish up the priority if-stmt body.  */
4226     finish_then_clause (priority_if_stmt);
4227     finish_if_stmt (priority_if_stmt);
4228
4229   } while (node);
4230
4231   /* Revert what __asan_before_dynamic_init did by calling
4232      __asan_after_dynamic_init.  */
4233   if (initp && (flag_sanitize & SANITIZE_ADDRESS))
4234     finish_expr_stmt (asan_dynamic_init_call (/*after_p=*/true));
4235
4236   /* Finish up the init/destruct if-stmt body.  */
4237   finish_then_clause (init_if_stmt);
4238   finish_if_stmt (init_if_stmt);
4239 }
4240
4241 /* VARS is a list of variables with static storage duration which may
4242    need initialization and/or finalization.  Remove those variables
4243    that don't really need to be initialized or finalized, and return
4244    the resulting list.  The order in which the variables appear in
4245    VARS is in reverse order of the order in which they should actually
4246    be initialized.  The list we return is in the unreversed order;
4247    i.e., the first variable should be initialized first.  */
4248
4249 static tree
4250 prune_vars_needing_no_initialization (tree *vars)
4251 {
4252   tree *var = vars;
4253   tree result = NULL_TREE;
4254
4255   while (*var)
4256     {
4257       tree t = *var;
4258       tree decl = TREE_VALUE (t);
4259       tree init = TREE_PURPOSE (t);
4260
4261       /* Deal gracefully with error.  */
4262       if (error_operand_p (decl))
4263         {
4264           var = &TREE_CHAIN (t);
4265           continue;
4266         }
4267
4268       /* The only things that can be initialized are variables.  */
4269       gcc_assert (VAR_P (decl));
4270
4271       /* If this object is not defined, we don't need to do anything
4272          here.  */
4273       if (DECL_EXTERNAL (decl))
4274         {
4275           var = &TREE_CHAIN (t);
4276           continue;
4277         }
4278
4279       /* Also, if the initializer already contains errors, we can bail
4280          out now.  */
4281       if (init && TREE_CODE (init) == TREE_LIST
4282           && value_member (error_mark_node, init))
4283         {
4284           var = &TREE_CHAIN (t);
4285           continue;
4286         }
4287
4288       /* This variable is going to need initialization and/or
4289          finalization, so we add it to the list.  */
4290       *var = TREE_CHAIN (t);
4291       TREE_CHAIN (t) = result;
4292       result = t;
4293     }
4294
4295   return result;
4296 }
4297
4298 /* Make sure we have told the back end about all the variables in
4299    VARS.  */
4300
4301 static void
4302 write_out_vars (tree vars)
4303 {
4304   tree v;
4305
4306   for (v = vars; v; v = TREE_CHAIN (v))
4307     {
4308       tree var = TREE_VALUE (v);
4309       if (!var_finalized_p (var))
4310         {
4311           import_export_decl (var);
4312           rest_of_decl_compilation (var, 1, 1);
4313         }
4314     }
4315 }
4316
4317 /* Generate a static constructor (if CONSTRUCTOR_P) or destructor
4318    (otherwise) that will initialize all global objects with static
4319    storage duration having the indicated PRIORITY.  */
4320
4321 static void
4322 generate_ctor_or_dtor_function (bool constructor_p, int priority,
4323                                 location_t *locus)
4324 {
4325   input_location = *locus;
4326
4327   /* We use `I' to indicate initialization and `D' to indicate
4328      destruction.  */
4329   char function_key = constructor_p ? 'I' : 'D';
4330
4331   /* We emit the function lazily, to avoid generating empty
4332      global constructors and destructors.  */
4333   tree body = NULL_TREE;
4334
4335   if (constructor_p && priority == DEFAULT_INIT_PRIORITY)
4336     {
4337       bool objc = c_dialect_objc () && objc_static_init_needed_p ();
4338
4339       /* We may have module initialization to emit and/or insert
4340          before other intializations.  */
4341       if (module_initializer_kind () || objc)
4342         body = start_objects (function_key, priority);
4343
4344       /* For Objective-C++, we may need to initialize metadata found
4345          in this module.  This must be done _before_ any other static
4346          initializations.  */
4347       if (objc)
4348         objc_generate_static_init_call (NULL_TREE);
4349     }
4350
4351   /* Call the static storage duration function with appropriate
4352      arguments.  */
4353   tree fndecl;
4354   size_t i;
4355   FOR_EACH_VEC_SAFE_ELT (ssdf_decls, i, fndecl)
4356     {
4357       /* Calls to pure or const functions will expand to nothing.  */
4358       if (! (flags_from_decl_or_type (fndecl) & (ECF_CONST | ECF_PURE)))
4359         {
4360           if (! body)
4361             body = start_objects (function_key, priority);
4362
4363           tree call = cp_build_function_call_nary (fndecl, tf_warning_or_error,
4364                                                    build_int_cst (NULL_TREE,
4365                                                                   constructor_p),
4366                                                    build_int_cst (NULL_TREE,
4367                                                                   priority),
4368                                                    NULL_TREE);
4369           finish_expr_stmt (call);
4370         }
4371     }
4372
4373   /* Close out the function.  */
4374   if (body)
4375     finish_objects (function_key, priority, body);
4376 }
4377
4378 /* Generate constructor and destructor functions for the priority
4379    indicated by N.  */
4380
4381 static int
4382 generate_ctor_and_dtor_functions_for_priority (splay_tree_node n, void * data)
4383 {
4384   location_t *locus = (location_t *) data;
4385   int priority = (int) n->key;
4386   priority_info pi = (priority_info) n->value;
4387
4388   /* Generate the functions themselves, but only if they are really
4389      needed.  */
4390   if (pi->initializations_p)
4391     generate_ctor_or_dtor_function (/*constructor_p=*/true, priority, locus);
4392   if (pi->destructions_p)
4393     generate_ctor_or_dtor_function (/*constructor_p=*/false, priority, locus);
4394
4395   /* Keep iterating.  */
4396   return 0;
4397 }
4398
4399 /* Return C++ property of T, based on given operation OP.  */
4400
4401 static int
4402 cpp_check (tree t, cpp_operation op)
4403 {
4404   switch (op)
4405     {
4406       case HAS_DEPENDENT_TEMPLATE_ARGS:
4407         {
4408           tree ti = CLASSTYPE_TEMPLATE_INFO (t);
4409           if (!ti)
4410             return 0;
4411           ++processing_template_decl;
4412           const bool dep = any_dependent_template_arguments_p (TI_ARGS (ti));
4413           --processing_template_decl;
4414           return dep;
4415         }
4416       case IS_ABSTRACT:
4417         return DECL_PURE_VIRTUAL_P (t);
4418       case IS_ASSIGNMENT_OPERATOR:
4419         return DECL_ASSIGNMENT_OPERATOR_P (t);
4420       case IS_CONSTRUCTOR:
4421         return DECL_CONSTRUCTOR_P (t);
4422       case IS_DESTRUCTOR:
4423         return DECL_DESTRUCTOR_P (t);
4424       case IS_COPY_CONSTRUCTOR:
4425         return DECL_COPY_CONSTRUCTOR_P (t);
4426       case IS_MOVE_CONSTRUCTOR:
4427         return DECL_MOVE_CONSTRUCTOR_P (t);
4428       case IS_TEMPLATE:
4429         return TREE_CODE (t) == TEMPLATE_DECL;
4430       case IS_TRIVIAL:
4431         return trivial_type_p (t);
4432       default:
4433         return 0;
4434     }
4435 }
4436
4437 /* Collect source file references recursively, starting from NAMESPC.  */
4438
4439 static void
4440 collect_source_refs (tree namespc)
4441 {
4442   /* Iterate over names in this name space.  */
4443   for (tree t = NAMESPACE_LEVEL (namespc)->names; t; t = TREE_CHAIN (t))
4444     if (DECL_IS_UNDECLARED_BUILTIN (t))
4445       ;
4446     else if (TREE_CODE (t) == NAMESPACE_DECL && !DECL_NAMESPACE_ALIAS (t))
4447       collect_source_refs (t);
4448     else
4449       collect_source_ref (DECL_SOURCE_FILE (t));
4450 }
4451
4452 /* Collect decls relevant to SOURCE_FILE from all namespaces recursively,
4453    starting from NAMESPC.  */
4454
4455 static void
4456 collect_ada_namespace (tree namespc, const char *source_file)
4457 {
4458   tree decl = NAMESPACE_LEVEL (namespc)->names;
4459
4460   /* Collect decls from this namespace.  This will skip
4461      NAMESPACE_DECLs (both aliases and regular, it cannot tell).  */
4462   collect_ada_nodes (decl, source_file);
4463
4464   /* Now scan for namespace children, and dump them.  */
4465   for (; decl; decl = TREE_CHAIN (decl))
4466     if (TREE_CODE (decl) == NAMESPACE_DECL && !DECL_NAMESPACE_ALIAS (decl))
4467       collect_ada_namespace (decl, source_file);
4468 }
4469
4470 /* Returns true iff there is a definition available for variable or
4471    function DECL.  */
4472
4473 bool
4474 decl_defined_p (tree decl)
4475 {
4476   if (TREE_CODE (decl) == FUNCTION_DECL)
4477     return (DECL_INITIAL (decl) != NULL_TREE
4478             /* A pending instantiation of a friend temploid is defined.  */
4479             || (DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (decl)
4480                 && DECL_INITIAL (DECL_TEMPLATE_RESULT
4481                                  (DECL_TI_TEMPLATE (decl)))));
4482   else
4483     {
4484       gcc_assert (VAR_P (decl));
4485       return !DECL_EXTERNAL (decl);
4486     }
4487 }
4488
4489 /* Nonzero for a VAR_DECL whose value can be used in a constant expression.
4490
4491       [expr.const]
4492
4493       An integral constant-expression can only involve ... const
4494       variables of integral or enumeration types initialized with
4495       constant expressions ...
4496
4497       C++0x also allows constexpr variables and temporaries initialized
4498       with constant expressions.  We handle the former here, but the latter
4499       are just folded away in cxx_eval_constant_expression.
4500
4501    The standard does not require that the expression be non-volatile.
4502    G++ implements the proposed correction in DR 457.  */
4503
4504 bool
4505 decl_constant_var_p (tree decl)
4506 {
4507   if (!decl_maybe_constant_var_p (decl))
4508     return false;
4509
4510   /* We don't know if a template static data member is initialized with
4511      a constant expression until we instantiate its initializer.  Even
4512      in the case of a constexpr variable, we can't treat it as a
4513      constant until its initializer is complete in case it's used in
4514      its own initializer.  */
4515   maybe_instantiate_decl (decl);
4516   return DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl);
4517 }
4518
4519 /* Returns true if DECL could be a symbolic constant variable, depending on
4520    its initializer.  */
4521
4522 bool
4523 decl_maybe_constant_var_p (tree decl)
4524 {
4525   tree type = TREE_TYPE (decl);
4526   if (!VAR_P (decl))
4527     return false;
4528   if (DECL_DECLARED_CONSTEXPR_P (decl) && !TREE_THIS_VOLATILE (decl))
4529     return true;
4530   if (DECL_HAS_VALUE_EXPR_P (decl))
4531     /* A proxy isn't constant.  */
4532     return false;
4533   if (TYPE_REF_P (type))
4534     /* References can be constant.  */;
4535   else if (CP_TYPE_CONST_NON_VOLATILE_P (type)
4536            && INTEGRAL_OR_ENUMERATION_TYPE_P (type))
4537     /* And const integers.  */;
4538   else
4539     return false;
4540
4541   if (DECL_INITIAL (decl)
4542       && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl))
4543     /* We know the initializer, and it isn't constant.  */
4544     return false;
4545   else
4546     return true;
4547 }
4548
4549 /* Complain that DECL uses a type with no linkage.  In C++98 mode this is
4550    called from grokfndecl and grokvardecl; in all modes it is called from
4551    cp_write_global_declarations.  */
4552
4553 void
4554 no_linkage_error (tree decl)
4555 {
4556   if (cxx_dialect >= cxx11
4557       && (decl_defined_p (decl)
4558           /* Treat templates which limit_bad_template_recursion decided
4559              not to instantiate as if they were defined.  */
4560           || (errorcount + sorrycount > 0
4561               && DECL_LANG_SPECIFIC (decl)
4562               && DECL_TEMPLATE_INFO (decl)
4563               && warning_suppressed_p (decl /* What warning? */))))
4564     /* In C++11 it's ok if the decl is defined.  */
4565     return;
4566
4567   if (DECL_LANG_SPECIFIC (decl) && DECL_MODULE_IMPORT_P (decl))
4568     /* An imported decl is ok.  */
4569     return;
4570
4571   tree t = no_linkage_check (TREE_TYPE (decl), /*relaxed_p=*/false);
4572   if (t == NULL_TREE)
4573     /* The type that got us on no_linkage_decls must have gotten a name for
4574        linkage purposes.  */;
4575   else if (CLASS_TYPE_P (t) && TYPE_BEING_DEFINED (t))
4576     // FIXME: This is now invalid, as a DR to c++98
4577     /* The type might end up having a typedef name for linkage purposes.  */
4578     vec_safe_push (no_linkage_decls, decl);
4579   else if (TYPE_UNNAMED_P (t))
4580     {
4581       bool d = false;
4582       auto_diagnostic_group grp;
4583       if (cxx_dialect >= cxx11)
4584         d = permerror (DECL_SOURCE_LOCATION (decl), "%q#D, declared using "
4585                        "unnamed type, is used but never defined", decl);
4586       else if (DECL_EXTERN_C_P (decl))
4587         /* Allow this; it's pretty common in C.  */;
4588       else if (VAR_P (decl))
4589         /* DRs 132, 319 and 389 seem to indicate types with
4590            no linkage can only be used to declare extern "C"
4591            entities.  Since it's not always an error in the
4592            ISO C++ 90 Standard, we only issue a warning.  */
4593         d = warning_at (DECL_SOURCE_LOCATION (decl), 0, "unnamed type "
4594                         "with no linkage used to declare variable %q#D with "
4595                         "linkage", decl);
4596       else
4597         d = permerror (DECL_SOURCE_LOCATION (decl), "unnamed type with no "
4598                        "linkage used to declare function %q#D with linkage",
4599                        decl);
4600       if (d && is_typedef_decl (TYPE_NAME (t)))
4601         inform (DECL_SOURCE_LOCATION (TYPE_NAME (t)), "%q#D does not refer "
4602                 "to the unqualified type, so it is not used for linkage",
4603                 TYPE_NAME (t));
4604     }
4605   else if (cxx_dialect >= cxx11)
4606     {
4607       if (VAR_P (decl) || !DECL_PURE_VIRTUAL_P (decl))
4608         permerror (DECL_SOURCE_LOCATION (decl),
4609                    "%q#D, declared using local type "
4610                    "%qT, is used but never defined", decl, t);
4611     }
4612   else if (VAR_P (decl))
4613     warning_at (DECL_SOURCE_LOCATION (decl), 0, "type %qT with no linkage "
4614                 "used to declare variable %q#D with linkage", t, decl);
4615   else
4616     permerror (DECL_SOURCE_LOCATION (decl), "type %qT with no linkage used "
4617                "to declare function %q#D with linkage", t, decl);
4618 }
4619
4620 /* Collect declarations from all namespaces relevant to SOURCE_FILE.  */
4621
4622 static void
4623 collect_all_refs (const char *source_file)
4624 {
4625   collect_ada_namespace (global_namespace, source_file);
4626 }
4627
4628 /* Clear DECL_EXTERNAL for NODE.  */
4629
4630 static bool
4631 clear_decl_external (struct cgraph_node *node, void * /*data*/)
4632 {
4633   DECL_EXTERNAL (node->decl) = 0;
4634   return false;
4635 }
4636
4637 /* Build up the function to run dynamic initializers for thread_local
4638    variables in this translation unit and alias the init functions for the
4639    individual variables to it.  */
4640
4641 static void
4642 handle_tls_init (void)
4643 {
4644   tree vars = prune_vars_needing_no_initialization (&tls_aggregates);
4645   if (vars == NULL_TREE)
4646     return;
4647
4648   location_t loc = DECL_SOURCE_LOCATION (TREE_VALUE (vars));
4649
4650   write_out_vars (vars);
4651
4652   tree guard = build_decl (loc, VAR_DECL, get_identifier ("__tls_guard"),
4653                            boolean_type_node);
4654   TREE_PUBLIC (guard) = false;
4655   TREE_STATIC (guard) = true;
4656   DECL_ARTIFICIAL (guard) = true;
4657   DECL_IGNORED_P (guard) = true;
4658   TREE_USED (guard) = true;
4659   CP_DECL_THREAD_LOCAL_P (guard) = true;
4660   set_decl_tls_model (guard, decl_default_tls_model (guard));
4661   pushdecl_top_level_and_finish (guard, NULL_TREE);
4662
4663   tree fn = get_local_tls_init_fn (loc);
4664   start_preparsed_function (fn, NULL_TREE, SF_PRE_PARSED);
4665   tree body = begin_function_body ();
4666   tree if_stmt = begin_if_stmt ();
4667   tree cond = cp_build_unary_op (TRUTH_NOT_EXPR, guard, false,
4668                                  tf_warning_or_error);
4669   finish_if_stmt_cond (cond, if_stmt);
4670   finish_expr_stmt (cp_build_modify_expr (loc, guard, NOP_EXPR,
4671                                           boolean_true_node,
4672                                           tf_warning_or_error));
4673   for (; vars; vars = TREE_CHAIN (vars))
4674     {
4675       tree var = TREE_VALUE (vars);
4676       tree init = TREE_PURPOSE (vars);
4677       one_static_initialization_or_destruction (var, init, true);
4678
4679       /* Output init aliases even with -fno-extern-tls-init.  */
4680       if (TARGET_SUPPORTS_ALIASES && TREE_PUBLIC (var))
4681         {
4682           tree single_init_fn = get_tls_init_fn (var);
4683           if (single_init_fn == NULL_TREE)
4684             continue;
4685           cgraph_node *alias
4686             = cgraph_node::get_create (fn)->create_same_body_alias
4687                 (single_init_fn, fn);
4688           gcc_assert (alias != NULL);
4689         }
4690     }
4691
4692   finish_then_clause (if_stmt);
4693   finish_if_stmt (if_stmt);
4694   finish_function_body (body);
4695   expand_or_defer_fn (finish_function (/*inline_p=*/false));
4696 }
4697
4698 /* We're at the end of compilation, so generate any mangling aliases that
4699    we've been saving up, if DECL is going to be output and ID2 isn't
4700    already taken by another declaration.  */
4701
4702 static void
4703 generate_mangling_alias (tree decl, tree id2)
4704 {
4705   struct cgraph_node *n = NULL;
4706
4707   if (TREE_CODE (decl) == FUNCTION_DECL)
4708     {
4709       n = cgraph_node::get (decl);
4710       if (!n)
4711         /* Don't create an alias to an unreferenced function.  */
4712         return;
4713     }
4714
4715   tree *slot
4716     = mangled_decls->find_slot_with_hash (id2, IDENTIFIER_HASH_VALUE (id2),
4717                                           INSERT);
4718
4719   /* If there's a declaration already using this mangled name,
4720      don't create a compatibility alias that conflicts.  */
4721   if (*slot)
4722     return;
4723
4724   tree alias = make_alias_for (decl, id2);
4725   *slot = alias;
4726
4727   DECL_IGNORED_P (alias) = 1;
4728   TREE_PUBLIC (alias) = TREE_PUBLIC (decl);
4729   DECL_VISIBILITY (alias) = DECL_VISIBILITY (decl);
4730   if (vague_linkage_p (decl))
4731     DECL_WEAK (alias) = 1;
4732
4733   if (n)
4734     n->create_same_body_alias (alias, decl);
4735   else
4736     varpool_node::create_extra_name_alias (alias, decl);
4737 }
4738
4739 /* Note that we might want to emit an alias with the symbol ID2 for DECL at
4740    the end of translation, for compatibility across bugs in the mangling
4741    implementation.  */
4742
4743 void
4744 note_mangling_alias (tree decl, tree id2)
4745 {
4746   if (TARGET_SUPPORTS_ALIASES)
4747     {
4748       if (!defer_mangling_aliases)
4749         generate_mangling_alias (decl, id2);
4750       else
4751         {
4752           vec_safe_push (mangling_aliases, decl);
4753           vec_safe_push (mangling_aliases, id2);
4754         }
4755     }
4756 }
4757
4758 /* Emit all mangling aliases that were deferred up to this point.  */
4759
4760 void
4761 generate_mangling_aliases ()
4762 {
4763   while (!vec_safe_is_empty (mangling_aliases))
4764     {
4765       tree id2 = mangling_aliases->pop();
4766       tree decl = mangling_aliases->pop();
4767       generate_mangling_alias (decl, id2);
4768     }
4769   defer_mangling_aliases = false;
4770 }
4771
4772 /* Record a mangling of DECL, whose DECL_ASSEMBLER_NAME has just been
4773    set.  NEED_WARNING is true if we must warn about collisions.  We do
4774    this to spot changes in mangling that may require compatibility
4775    aliases.  */
4776
4777 void
4778 record_mangling (tree decl, bool need_warning)
4779 {
4780   if (!mangled_decls)
4781     mangled_decls = hash_table<mangled_decl_hash>::create_ggc (499);
4782
4783   gcc_checking_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
4784   tree id = DECL_ASSEMBLER_NAME_RAW (decl);
4785   tree *slot
4786     = mangled_decls->find_slot_with_hash (id, IDENTIFIER_HASH_VALUE (id),
4787                                           INSERT);
4788
4789   /* If this is already an alias, remove the alias, because the real
4790      decl takes precedence.  */
4791   if (*slot && DECL_ARTIFICIAL (*slot) && DECL_IGNORED_P (*slot))
4792     if (symtab_node *n = symtab_node::get (*slot))
4793       if (n->cpp_implicit_alias)
4794         {
4795           n->remove ();
4796           *slot = NULL_TREE;
4797         }
4798
4799   if (!*slot)
4800     *slot = decl;
4801   else if (need_warning)
4802     {
4803       error_at (DECL_SOURCE_LOCATION (decl),
4804                 "mangling of %q#D as %qE conflicts with a previous mangle",
4805                 decl, id);
4806       inform (DECL_SOURCE_LOCATION (*slot),
4807               "previous mangling %q#D", *slot);
4808       inform (DECL_SOURCE_LOCATION (decl),
4809               "a later %<-fabi-version=%> (or =0)"
4810               " avoids this error with a change in mangling");
4811       *slot = decl;
4812     }
4813 }
4814
4815 /* The mangled name of DECL is being forcibly changed to NAME.  Remove
4816    any existing knowledge of DECL's mangled name meaning DECL.  */
4817
4818 void
4819 overwrite_mangling (tree decl, tree name)
4820 {
4821   if (tree id = DECL_ASSEMBLER_NAME_RAW (decl))
4822     if ((TREE_CODE (decl) == VAR_DECL
4823          || TREE_CODE (decl) == FUNCTION_DECL)
4824         && mangled_decls)
4825       if (tree *slot
4826           = mangled_decls->find_slot_with_hash (id, IDENTIFIER_HASH_VALUE (id),
4827                                                 NO_INSERT))
4828         if (*slot == decl)
4829           {
4830             mangled_decls->clear_slot (slot);
4831
4832             /* If this is an alias, remove it from the symbol table.  */
4833             if (DECL_ARTIFICIAL (decl) && DECL_IGNORED_P (decl))
4834               if (symtab_node *n = symtab_node::get (decl))
4835                 if (n->cpp_implicit_alias)
4836                   n->remove ();
4837           }
4838
4839   DECL_ASSEMBLER_NAME_RAW (decl) = name;
4840 }
4841
4842 /* The entire file is now complete.  If requested, dump everything
4843    to a file.  */
4844
4845 static void
4846 dump_tu (void)
4847 {
4848   dump_flags_t flags;
4849   if (FILE *stream = dump_begin (raw_dump_id, &flags))
4850     {
4851       dump_node (global_namespace, flags & ~TDF_SLIM, stream);
4852       dump_end (raw_dump_id, stream);
4853     }
4854 }
4855
4856 static location_t locus_at_end_of_parsing;
4857
4858 /* Check the deallocation functions for CODE to see if we want to warn that
4859    only one was defined.  */
4860
4861 static void
4862 maybe_warn_sized_delete (enum tree_code code)
4863 {
4864   tree sized = NULL_TREE;
4865   tree unsized = NULL_TREE;
4866
4867   for (ovl_iterator iter (get_global_binding (ovl_op_identifier (false, code)));
4868        iter; ++iter)
4869     {
4870       tree fn = *iter;
4871       /* We're only interested in usual deallocation functions.  */
4872       if (!usual_deallocation_fn_p (fn))
4873         continue;
4874       if (FUNCTION_ARG_CHAIN (fn) == void_list_node)
4875         unsized = fn;
4876       else
4877         sized = fn;
4878     }
4879   if (DECL_INITIAL (unsized) && !DECL_INITIAL (sized))
4880     warning_at (DECL_SOURCE_LOCATION (unsized), OPT_Wsized_deallocation,
4881                 "the program should also define %qD", sized);
4882   else if (!DECL_INITIAL (unsized) && DECL_INITIAL (sized))
4883     warning_at (DECL_SOURCE_LOCATION (sized), OPT_Wsized_deallocation,
4884                 "the program should also define %qD", unsized);
4885 }
4886
4887 /* Check the global deallocation functions to see if we want to warn about
4888    defining unsized without sized (or vice versa).  */
4889
4890 static void
4891 maybe_warn_sized_delete ()
4892 {
4893   if (!flag_sized_deallocation || !warn_sized_deallocation)
4894     return;
4895   maybe_warn_sized_delete (DELETE_EXPR);
4896   maybe_warn_sized_delete (VEC_DELETE_EXPR);
4897 }
4898
4899 /* Earlier we left PTRMEM_CST in variable initializers alone so that we could
4900    look them up when evaluating non-type template parameters.  Now we need to
4901    lower them to something the back end can understand.  */
4902
4903 static void
4904 lower_var_init ()
4905 {
4906   varpool_node *node;
4907   FOR_EACH_VARIABLE (node)
4908     {
4909       tree d = node->decl;
4910       if (tree init = DECL_INITIAL (d))
4911         DECL_INITIAL (d) = cplus_expand_constant (init);
4912     }
4913 }
4914
4915 /* This routine is called at the end of compilation.
4916    Its job is to create all the code needed to initialize and
4917    destroy the global aggregates.  We do the destruction
4918    first, since that way we only need to reverse the decls once.  */
4919
4920 void
4921 c_parse_final_cleanups (void)
4922 {
4923   size_t i;
4924   tree decl;
4925
4926   locus_at_end_of_parsing = input_location;
4927   at_eof = 1;
4928
4929   /* Bad parse errors.  Just forget about it.  */
4930   if (! global_bindings_p () || current_class_type
4931       || !vec_safe_is_empty (decl_namespace_list))
4932     return;
4933
4934   /* This is the point to write out a PCH if we're doing that.
4935      In that case we do not want to do anything else.  */
4936   if (pch_file)
4937     {
4938       /* Mangle all symbols at PCH creation time.  */
4939       symtab_node *node;
4940       FOR_EACH_SYMBOL (node)
4941         if (! is_a <varpool_node *> (node)
4942             || ! DECL_HARD_REGISTER (node->decl))
4943           DECL_ASSEMBLER_NAME (node->decl);
4944       c_common_write_pch ();
4945       dump_tu ();
4946       /* Ensure even the callers don't try to finalize the CU.  */
4947       flag_syntax_only = 1;
4948       return;
4949     }
4950
4951   timevar_stop (TV_PHASE_PARSING);
4952   timevar_start (TV_PHASE_DEFERRED);
4953
4954   symtab->process_same_body_aliases ();
4955
4956   /* Handle -fdump-ada-spec[-slim] */
4957   if (flag_dump_ada_spec || flag_dump_ada_spec_slim)
4958     {
4959       collect_source_ref (main_input_filename);
4960       if (!flag_dump_ada_spec_slim)
4961         collect_source_refs (global_namespace);
4962
4963       dump_ada_specs (collect_all_refs, cpp_check);
4964     }
4965
4966   /* FIXME - huh?  was  input_line -= 1;*/
4967
4968   /* We now have to write out all the stuff we put off writing out.
4969      These include:
4970
4971        o Template specializations that we have not yet instantiated,
4972          but which are needed.
4973        o Initialization and destruction for non-local objects with
4974          static storage duration.  (Local objects with static storage
4975          duration are initialized when their scope is first entered,
4976          and are cleaned up via atexit.)
4977        o Virtual function tables.
4978
4979      All of these may cause others to be needed.  For example,
4980      instantiating one function may cause another to be needed, and
4981      generating the initializer for an object may cause templates to be
4982      instantiated, etc., etc.  */
4983
4984   emit_support_tinfos ();
4985
4986   /* Track vtables we want to emit that refer to consteval functions.  */
4987   auto_vec<tree> consteval_vtables;
4988
4989   int retries = 0;
4990   unsigned ssdf_count = 0;
4991   for (bool reconsider = true; reconsider; retries++)
4992     {
4993       reconsider = false;
4994
4995       /* If there are templates that we've put off instantiating, do
4996          them now.  */
4997       instantiate_pending_templates (retries);
4998       ggc_collect ();
4999
5000       if (header_module_p ())
5001         /* A header modules initializations are handled in its
5002            importer.  */
5003         continue;
5004
5005       /* Write out virtual tables as required.  Writing out the
5006          virtual table for a template class may cause the
5007          instantiation of members of that class.  If we write out
5008          vtables then we remove the class from our list so we don't
5009          have to look at it again.  */
5010       tree t;
5011       for (i = keyed_classes->length ();
5012            keyed_classes->iterate (--i, &t);)
5013         if (maybe_emit_vtables (t, consteval_vtables))
5014           {
5015             reconsider = true;
5016             keyed_classes->unordered_remove (i);
5017           }
5018       /* The input_location may have been changed during marking of
5019          vtable entries.  */
5020       input_location = locus_at_end_of_parsing;
5021
5022       /* Write out needed type info variables.  We have to be careful
5023          looping through unemitted decls, because emit_tinfo_decl may
5024          cause other variables to be needed. New elements will be
5025          appended, and we remove from the vector those that actually
5026          get emitted.  */
5027       for (i = unemitted_tinfo_decls->length ();
5028            unemitted_tinfo_decls->iterate (--i, &t);)
5029         if (emit_tinfo_decl (t))
5030           {
5031             reconsider = true;
5032             unemitted_tinfo_decls->unordered_remove (i);
5033           }
5034
5035       /* The list of objects with static storage duration is built up
5036          in reverse order.  We clear STATIC_AGGREGATES so that any new
5037          aggregates added during the initialization of these will be
5038          initialized in the correct order when we next come around the
5039          loop.  */
5040       if (tree vars = prune_vars_needing_no_initialization (&static_aggregates))
5041         {
5042           if (flag_openmp)
5043             /* Add initializer information from VARS into
5044                DYNAMIC_INITIALIZERS.  */
5045             for (t = vars; t; t = TREE_CHAIN (t))
5046               hash_map_safe_put<hm_ggc> (dynamic_initializers,
5047                                          TREE_VALUE (t), TREE_PURPOSE (t));
5048
5049           /* We need to start a new initialization function each time
5050              through the loop.  That's because we need to know which
5051              vtables have been referenced, and TREE_SYMBOL_REFERENCED
5052              isn't computed until a function is finished, and written
5053              out.  That's a deficiency in the back end.  When this is
5054              fixed, these initialization functions could all become
5055              inline, with resulting performance improvements.  */
5056           tree ssdf_body;
5057
5058           /* Make sure the back end knows about all the variables.  */
5059           write_out_vars (vars);
5060
5061           /* Set the line and file, so that it is obviously not from
5062              the source file.  */
5063           input_location = locus_at_end_of_parsing;
5064           ssdf_body = start_static_storage_duration_function (ssdf_count);
5065
5066           /* First generate code to do all the initializations.  */
5067           if (vars)
5068             do_static_initialization_or_destruction (vars, /*initp=*/true);
5069
5070           /* Then, generate code to do all the destructions.  Do these
5071              in reverse order so that the most recently constructed
5072              variable is the first destroyed.  If we're using
5073              __cxa_atexit, then we don't need to do this; functions
5074              were registered at initialization time to destroy the
5075              local statics.  */
5076           if (!flag_use_cxa_atexit && vars)
5077             {
5078               vars = nreverse (vars);
5079               do_static_initialization_or_destruction (vars, /*initp=*/false);
5080             }
5081           else
5082             vars = NULL_TREE;
5083
5084           /* Finish up the static storage duration function for this
5085              round.  */
5086           input_location = locus_at_end_of_parsing;
5087           finish_static_storage_duration_function (ssdf_body);
5088
5089           /* All those initializations and finalizations might cause
5090              us to need more inline functions, more template
5091              instantiations, etc.  */
5092           reconsider = true;
5093           ssdf_count++;
5094         }
5095
5096       /* Now do the same for thread_local variables.  */
5097       handle_tls_init ();
5098
5099       /* Go through the set of inline functions whose bodies have not
5100          been emitted yet.  If out-of-line copies of these functions
5101          are required, emit them.  */
5102       FOR_EACH_VEC_SAFE_ELT (deferred_fns, i, decl)
5103         {
5104           /* Does it need synthesizing?  */
5105           if (DECL_DEFAULTED_FN (decl) && ! DECL_INITIAL (decl)
5106               && (! DECL_REALLY_EXTERN (decl) || possibly_inlined_p (decl)))
5107             {
5108               /* Even though we're already at the top-level, we push
5109                  there again.  That way, when we pop back a few lines
5110                  hence, all of our state is restored.  Otherwise,
5111                  finish_function doesn't clean things up, and we end
5112                  up with CURRENT_FUNCTION_DECL set.  */
5113               push_to_top_level ();
5114               /* The decl's location will mark where it was first
5115                  needed.  Save that so synthesize method can indicate
5116                  where it was needed from, in case of error  */
5117               input_location = DECL_SOURCE_LOCATION (decl);
5118               synthesize_method (decl);
5119               pop_from_top_level ();
5120               reconsider = true;
5121             }
5122
5123           if (!DECL_INITIAL (decl) && decl_tls_wrapper_p (decl))
5124             generate_tls_wrapper (decl);
5125
5126           if (!DECL_SAVED_TREE (decl))
5127             continue;
5128
5129           cgraph_node *node = cgraph_node::get_create (decl);
5130
5131           /* We lie to the back end, pretending that some functions
5132              are not defined when they really are.  This keeps these
5133              functions from being put out unnecessarily.  But, we must
5134              stop lying when the functions are referenced, or if they
5135              are not comdat since they need to be put out now.  If
5136              DECL_INTERFACE_KNOWN, then we have already set
5137              DECL_EXTERNAL appropriately, so there's no need to check
5138              again, and we do not want to clear DECL_EXTERNAL if a
5139              previous call to import_export_decl set it.
5140
5141              This is done in a separate for cycle, because if some
5142              deferred function is contained in another deferred
5143              function later in deferred_fns varray,
5144              rest_of_compilation would skip this function and we
5145              really cannot expand the same function twice.  */
5146           import_export_decl (decl);
5147           if (DECL_NOT_REALLY_EXTERN (decl)
5148               && DECL_INITIAL (decl)
5149               && decl_needed_p (decl))
5150             {
5151               if (node->cpp_implicit_alias)
5152                 node = node->get_alias_target ();
5153
5154               node->call_for_symbol_thunks_and_aliases (clear_decl_external,
5155                                                       NULL, true);
5156               /* If we mark !DECL_EXTERNAL one of the symbols in some comdat
5157                  group, we need to mark all symbols in the same comdat group
5158                  that way.  */
5159               if (node->same_comdat_group)
5160                 for (cgraph_node *next
5161                        = dyn_cast<cgraph_node *> (node->same_comdat_group);
5162                      next != node;
5163                      next = dyn_cast<cgraph_node *> (next->same_comdat_group))
5164                   next->call_for_symbol_thunks_and_aliases (clear_decl_external,
5165                                                           NULL, true);
5166             }
5167
5168           /* If we're going to need to write this function out, and
5169              there's already a body for it, create RTL for it now.
5170              (There might be no body if this is a method we haven't
5171              gotten around to synthesizing yet.)  */
5172           if (!DECL_EXTERNAL (decl)
5173               && decl_needed_p (decl)
5174               && !TREE_ASM_WRITTEN (decl)
5175               && !node->definition)
5176             {
5177               /* We will output the function; no longer consider it in this
5178                  loop.  */
5179               DECL_DEFER_OUTPUT (decl) = 0;
5180               /* Generate RTL for this function now that we know we
5181                  need it.  */
5182               expand_or_defer_fn (decl);
5183               reconsider = true;
5184             }
5185         }
5186
5187       if (wrapup_namespace_globals ())
5188         reconsider = true;
5189
5190       /* Static data members are just like namespace-scope globals.  */
5191       FOR_EACH_VEC_SAFE_ELT (pending_statics, i, decl)
5192         {
5193           if (var_finalized_p (decl) || DECL_REALLY_EXTERN (decl)
5194               /* Don't write it out if we haven't seen a definition.  */
5195               || DECL_IN_AGGR_P (decl))
5196             continue;
5197           import_export_decl (decl);
5198           /* If this static data member is needed, provide it to the
5199              back end.  */
5200           if (DECL_NOT_REALLY_EXTERN (decl) && decl_needed_p (decl))
5201             DECL_EXTERNAL (decl) = 0;
5202         }
5203
5204       if (vec_safe_length (pending_statics) != 0
5205           && wrapup_global_declarations (pending_statics->address (),
5206                                          pending_statics->length ()))
5207         reconsider = true;
5208     }
5209
5210   finish_module_processing (parse_in);
5211
5212   lower_var_init ();
5213
5214   generate_mangling_aliases ();
5215
5216   /* All used inline functions must have a definition at this point.  */
5217   FOR_EACH_VEC_SAFE_ELT (deferred_fns, i, decl)
5218     {
5219       if (/* Check online inline functions that were actually used.  */
5220           DECL_ODR_USED (decl) && DECL_DECLARED_INLINE_P (decl)
5221           /* If the definition actually was available here, then the
5222              fact that the function was not defined merely represents
5223              that for some reason (use of a template repository,
5224              #pragma interface, etc.) we decided not to emit the
5225              definition here.  */
5226           && !DECL_INITIAL (decl)
5227           /* A defaulted fn in a header module can be synthesized on
5228              demand later.  (In non-header modules we should have
5229              synthesized it above.)  */
5230           && !(DECL_DEFAULTED_FN (decl) && header_module_p ())
5231           /* Don't complain if the template was defined.  */
5232           && !(DECL_TEMPLATE_INSTANTIATION (decl)
5233                && DECL_INITIAL (DECL_TEMPLATE_RESULT
5234                                 (template_for_substitution (decl))))
5235           && warning_at (DECL_SOURCE_LOCATION (decl), 0,
5236                          "inline function %qD used but never defined", decl))
5237         /* Avoid a duplicate warning from check_global_declaration.  */
5238         suppress_warning (decl, OPT_Wunused);
5239     }
5240
5241   /* So must decls that use a type with no linkage.  */
5242   FOR_EACH_VEC_SAFE_ELT (no_linkage_decls, i, decl)
5243     no_linkage_error (decl);
5244
5245   maybe_warn_sized_delete ();
5246
5247   /* Then, do the Objective-C stuff.  This is where all the
5248      Objective-C module stuff gets generated (symtab,
5249      class/protocol/selector lists etc).  This must be done after C++
5250      templates, destructors etc. so that selectors used in C++
5251      templates are properly allocated.  */
5252   if (c_dialect_objc ())
5253     objc_write_global_declarations ();
5254
5255   /* We give C linkage to static constructors and destructors.  */
5256   push_lang_context (lang_name_c);
5257
5258   /* Generate initialization and destruction functions for all
5259      priorities for which they are required.  */
5260   if (priority_info_map)
5261     splay_tree_foreach (priority_info_map,
5262                         generate_ctor_and_dtor_functions_for_priority,
5263                         /*data=*/&locus_at_end_of_parsing);
5264   else if ((c_dialect_objc () && objc_static_init_needed_p ())
5265            || module_initializer_kind ())
5266     generate_ctor_or_dtor_function (/*constructor_p=*/true,
5267                                     DEFAULT_INIT_PRIORITY,
5268                                     &locus_at_end_of_parsing);
5269
5270   /* We're done with the splay-tree now.  */
5271   if (priority_info_map)
5272     splay_tree_delete (priority_info_map);
5273
5274   fini_modules ();
5275
5276   /* Generate any missing aliases.  */
5277   maybe_apply_pending_pragma_weaks ();
5278
5279   /* We're done with static constructors, so we can go back to "C++"
5280      linkage now.  */
5281   pop_lang_context ();
5282
5283   if (flag_vtable_verify)
5284     {
5285       vtv_recover_class_info ();
5286       vtv_compute_class_hierarchy_transitive_closure ();
5287       vtv_build_vtable_verify_fndecl ();
5288     }
5289
5290   perform_deferred_noexcept_checks ();
5291
5292   fini_constexpr ();
5293   cp_tree_c_finish_parsing ();
5294   clear_consteval_vfns (consteval_vtables);
5295
5296   /* The entire file is now complete.  If requested, dump everything
5297      to a file.  */
5298   dump_tu ();
5299
5300   if (flag_detailed_statistics)
5301     {
5302       dump_tree_statistics ();
5303       dump_time_statistics ();
5304     }
5305
5306   timevar_stop (TV_PHASE_DEFERRED);
5307   timevar_start (TV_PHASE_PARSING);
5308
5309   /* Indicate that we're done with front end processing.  */
5310   at_eof = 2;
5311 }
5312
5313 /* Perform any post compilation-proper cleanups for the C++ front-end.
5314    This should really go away.  No front-end should need to do
5315    anything past the compilation process.  */
5316
5317 void
5318 cxx_post_compilation_parsing_cleanups (void)
5319 {
5320   timevar_start (TV_PHASE_LATE_PARSING_CLEANUPS);
5321
5322   if (flag_vtable_verify)
5323     {
5324       /* Generate the special constructor initialization function that
5325          calls __VLTRegisterPairs, and give it a very high
5326          initialization priority.  This must be done after
5327          finalize_compilation_unit so that we have accurate
5328          information about which vtable will actually be emitted.  */
5329       vtv_generate_init_routine ();
5330     }
5331
5332   input_location = locus_at_end_of_parsing;
5333
5334   if (flag_checking)
5335     validate_conversion_obstack ();
5336
5337   timevar_stop (TV_PHASE_LATE_PARSING_CLEANUPS);
5338 }
5339
5340 /* FN is an OFFSET_REF, DOTSTAR_EXPR or MEMBER_REF indicating the
5341    function to call in parse-tree form; it has not yet been
5342    semantically analyzed.  ARGS are the arguments to the function.
5343    They have already been semantically analyzed.  This may change
5344    ARGS.  */
5345
5346 tree
5347 build_offset_ref_call_from_tree (tree fn, vec<tree, va_gc> **args,
5348                                  tsubst_flags_t complain)
5349 {
5350   tree orig_fn;
5351   vec<tree, va_gc> *orig_args = NULL;
5352   tree expr;
5353   tree object;
5354
5355   orig_fn = fn;
5356   object = TREE_OPERAND (fn, 0);
5357
5358   if (processing_template_decl)
5359     {
5360       gcc_assert (TREE_CODE (fn) == DOTSTAR_EXPR
5361                   || TREE_CODE (fn) == MEMBER_REF);
5362       if (type_dependent_expression_p (fn)
5363           || any_type_dependent_arguments_p (*args))
5364         return build_min_nt_call_vec (fn, *args);
5365
5366       orig_args = make_tree_vector_copy (*args);
5367
5368       /* Transform the arguments and add the implicit "this"
5369          parameter.  That must be done before the FN is transformed
5370          because we depend on the form of FN.  */
5371       make_args_non_dependent (*args);
5372       object = build_non_dependent_expr (object);
5373       if (TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
5374         {
5375           if (TREE_CODE (fn) == DOTSTAR_EXPR)
5376             object = cp_build_addr_expr (object, complain);
5377           vec_safe_insert (*args, 0, object);
5378         }
5379       /* Now that the arguments are done, transform FN.  */
5380       fn = build_non_dependent_expr (fn);
5381     }
5382
5383   /* A qualified name corresponding to a bound pointer-to-member is
5384      represented as an OFFSET_REF:
5385
5386         struct B { void g(); };
5387         void (B::*p)();
5388         void B::g() { (this->*p)(); }  */
5389   if (TREE_CODE (fn) == OFFSET_REF)
5390     {
5391       tree object_addr = cp_build_addr_expr (object, complain);
5392       fn = TREE_OPERAND (fn, 1);
5393       fn = get_member_function_from_ptrfunc (&object_addr, fn,
5394                                              complain);
5395       vec_safe_insert (*args, 0, object_addr);
5396     }
5397
5398   if (CLASS_TYPE_P (TREE_TYPE (fn)))
5399     expr = build_op_call (fn, args, complain);
5400   else
5401     expr = cp_build_function_call_vec (fn, args, complain);
5402   if (processing_template_decl && expr != error_mark_node)
5403     expr = build_min_non_dep_call_vec (expr, orig_fn, orig_args);
5404
5405   if (orig_args != NULL)
5406     release_tree_vector (orig_args);
5407
5408   return expr;
5409 }
5410
5411
5412 void
5413 check_default_args (tree x)
5414 {
5415   tree arg = TYPE_ARG_TYPES (TREE_TYPE (x));
5416   bool saw_def = false;
5417   bool noted_first_def = false;
5418   int idx_of_first_default_arg = 0;
5419   location_t loc_of_first_default_arg = UNKNOWN_LOCATION;
5420   int i = 0 - (TREE_CODE (TREE_TYPE (x)) == METHOD_TYPE);
5421   tree fndecl = STRIP_TEMPLATE (x);
5422   auto_diagnostic_group d;
5423   for (; arg && arg != void_list_node; arg = TREE_CHAIN (arg), ++i)
5424     {
5425       if (TREE_PURPOSE (arg))
5426         {
5427           if (!saw_def)
5428             {
5429               saw_def = true;
5430               idx_of_first_default_arg = i;
5431               location_t loc = get_fndecl_argument_location (fndecl, i);
5432               if (loc != DECL_SOURCE_LOCATION (x))
5433                 loc_of_first_default_arg = loc;
5434             }
5435         }
5436       else if (saw_def && !PACK_EXPANSION_P (TREE_VALUE (arg)))
5437         {
5438           error_at (get_fndecl_argument_location (fndecl, i),
5439                     "default argument missing for parameter %P of %q#D", i, x);
5440           if (loc_of_first_default_arg != UNKNOWN_LOCATION
5441               && !noted_first_def)
5442             {
5443               inform (loc_of_first_default_arg,
5444                       "...following parameter %P which has a default argument",
5445                       idx_of_first_default_arg);
5446               noted_first_def = true;
5447             }
5448           TREE_PURPOSE (arg) = error_mark_node;
5449         }
5450     }
5451 }
5452
5453 /* Return true if function DECL can be inlined.  This is used to force
5454    instantiation of methods that might be interesting for inlining.  */
5455 bool
5456 possibly_inlined_p (tree decl)
5457 {
5458   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL);
5459   if (DECL_UNINLINABLE (decl))
5460     return false;
5461   if (!optimize)
5462     return DECL_DECLARED_INLINE_P (decl);
5463   /* When optimizing, we might inline everything when flatten
5464      attribute or heuristics inlining for size or autoinlining
5465      is used.  */
5466   return true;
5467 }
5468
5469 /* Normally, we can wait until instantiation-time to synthesize DECL.
5470    However, if DECL is a static data member initialized with a constant
5471    or a constexpr function, we need it right now because a reference to
5472    such a data member or a call to such function is not value-dependent.
5473    For a function that uses auto in the return type, we need to instantiate
5474    it to find out its type.  For OpenMP user defined reductions, we need
5475    them instantiated for reduction clauses which inline them by hand
5476    directly.  */
5477
5478 void
5479 maybe_instantiate_decl (tree decl)
5480 {
5481   if (DECL_LANG_SPECIFIC (decl)
5482       && DECL_TEMPLATE_INFO (decl)
5483       && (decl_maybe_constant_var_p (decl)
5484           || (TREE_CODE (decl) == FUNCTION_DECL
5485               && DECL_OMP_DECLARE_REDUCTION_P (decl))
5486           || undeduced_auto_decl (decl))
5487       && !DECL_DECLARED_CONCEPT_P (decl)
5488       && !uses_template_parms (DECL_TI_ARGS (decl)))
5489     {
5490       /* Instantiating a function will result in garbage collection.  We
5491          must treat this situation as if we were within the body of a
5492          function so as to avoid collecting live data only referenced from
5493          the stack (such as overload resolution candidates).  */
5494       ++function_depth;
5495       instantiate_decl (decl, /*defer_ok=*/false,
5496                         /*expl_inst_class_mem_p=*/false);
5497       --function_depth;
5498     }
5499 }
5500
5501 /* Maybe warn if DECL is deprecated, subject to COMPLAIN.  Returns whether or
5502    not a warning was emitted.  */
5503
5504 bool
5505 cp_warn_deprecated_use (tree decl, tsubst_flags_t complain)
5506 {
5507   if (!(complain & tf_warning) || !decl
5508       || deprecated_state == DEPRECATED_SUPPRESS)
5509     return false;
5510
5511   if (!TREE_DEPRECATED (decl))
5512     {
5513       /* Perhaps this is a deprecated typedef.  */
5514       if (TYPE_P (decl) && TYPE_NAME (decl))
5515         decl = TYPE_NAME (decl);
5516
5517       if (!TREE_DEPRECATED (decl))
5518         return false;
5519     }
5520
5521   /* Don't warn within members of a deprecated type.  */
5522   if (TYPE_P (decl)
5523       && currently_open_class (decl))
5524     return false;
5525
5526   bool warned = false;
5527   if (cxx_dialect >= cxx11
5528       && DECL_P (decl)
5529       && DECL_ARTIFICIAL (decl)
5530       && DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)
5531       && copy_fn_p (decl))
5532     {
5533       /* Don't warn if the flag was disabled around the class definition
5534          (c++/94492).  */
5535       if (warning_enabled_at (DECL_SOURCE_LOCATION (decl),
5536                               OPT_Wdeprecated_copy))
5537         {
5538           auto_diagnostic_group d;
5539           tree ctx = DECL_CONTEXT (decl);
5540           tree other = classtype_has_depr_implicit_copy (ctx);
5541           int opt = (DECL_DESTRUCTOR_P (other)
5542                      ? OPT_Wdeprecated_copy_dtor
5543                      : OPT_Wdeprecated_copy);
5544           warned = warning (opt, "implicitly-declared %qD is deprecated",
5545                             decl);
5546           if (warned)
5547             inform (DECL_SOURCE_LOCATION (other),
5548                     "because %qT has user-provided %qD",
5549                     ctx, other);
5550         }
5551     }
5552   else
5553     warned = warn_deprecated_use (decl, NULL_TREE);
5554
5555   return warned;
5556 }
5557
5558 /* Like above, but takes into account outer scopes.  */
5559
5560 void
5561 cp_warn_deprecated_use_scopes (tree scope)
5562 {
5563   while (scope
5564          && scope != error_mark_node
5565          && scope != global_namespace)
5566     {
5567       if ((TREE_CODE (scope) == NAMESPACE_DECL || OVERLOAD_TYPE_P (scope))
5568           && cp_warn_deprecated_use (scope))
5569         return;
5570       if (TYPE_P (scope))
5571         scope = CP_TYPE_CONTEXT (scope);
5572       else
5573         scope = CP_DECL_CONTEXT (scope);
5574     }
5575 }
5576
5577 /* True if DECL or its enclosing scope have unbound template parameters.  */
5578
5579 bool
5580 decl_dependent_p (tree decl)
5581 {
5582   if (DECL_FUNCTION_SCOPE_P (decl)
5583       || TREE_CODE (decl) == CONST_DECL
5584       || TREE_CODE (decl) == USING_DECL
5585       || TREE_CODE (decl) == FIELD_DECL)
5586     decl = CP_DECL_CONTEXT (decl);
5587   if (tree tinfo = get_template_info (decl))
5588     if (any_dependent_template_arguments_p (TI_ARGS (tinfo)))
5589       return true;
5590   if (LAMBDA_FUNCTION_P (decl)
5591       && dependent_type_p (DECL_CONTEXT (decl)))
5592     return true;
5593   return false;
5594 }
5595
5596 /* Mark DECL (either a _DECL or a BASELINK) as "used" in the program.
5597    If DECL is a specialization or implicitly declared class member,
5598    generate the actual definition.  Return false if something goes
5599    wrong, true otherwise.  */
5600
5601 bool
5602 mark_used (tree decl, tsubst_flags_t complain)
5603 {
5604   /* If we're just testing conversions or resolving overloads, we
5605      don't want any permanent effects like forcing functions to be
5606      output or instantiating templates.  */
5607   if ((complain & tf_conv))
5608     return true;
5609
5610   /* If DECL is a BASELINK for a single function, then treat it just
5611      like the DECL for the function.  Otherwise, if the BASELINK is
5612      for an overloaded function, we don't know which function was
5613      actually used until after overload resolution.  */
5614   if (BASELINK_P (decl))
5615     {
5616       decl = BASELINK_FUNCTIONS (decl);
5617       if (really_overloaded_fn (decl))
5618         return true;
5619       decl = OVL_FIRST (decl);
5620     }
5621
5622   if (!DECL_P (decl))
5623     return true;
5624
5625   /* Set TREE_USED for the benefit of -Wunused.  */
5626   TREE_USED (decl) = true;
5627
5628   /* And for structured bindings also the underlying decl.  */
5629   if (DECL_DECOMPOSITION_P (decl) && DECL_DECOMP_BASE (decl))
5630     TREE_USED (DECL_DECOMP_BASE (decl)) = true;
5631
5632   if (TREE_CODE (decl) == TEMPLATE_DECL)
5633     return true;
5634
5635   if (DECL_CLONED_FUNCTION_P (decl))
5636     TREE_USED (DECL_CLONED_FUNCTION (decl)) = 1;
5637
5638   /* Mark enumeration types as used.  */
5639   if (TREE_CODE (decl) == CONST_DECL)
5640     used_types_insert (DECL_CONTEXT (decl));
5641
5642   if (TREE_CODE (decl) == FUNCTION_DECL
5643       && !maybe_instantiate_noexcept (decl, complain))
5644     return false;
5645
5646   if (TREE_CODE (decl) == FUNCTION_DECL
5647       && DECL_DELETED_FN (decl))
5648     {
5649       if (DECL_ARTIFICIAL (decl)
5650           && DECL_CONV_FN_P (decl)
5651           && LAMBDA_TYPE_P (DECL_CONTEXT (decl)))
5652         /* We mark a lambda conversion op as deleted if we can't
5653            generate it properly; see maybe_add_lambda_conv_op.  */
5654         sorry ("converting lambda that uses %<...%> to function pointer");
5655       else if (complain & tf_error)
5656         {
5657           error ("use of deleted function %qD", decl);
5658           if (!maybe_explain_implicit_delete (decl))
5659             inform (DECL_SOURCE_LOCATION (decl), "declared here");
5660         }
5661       return false;
5662     }
5663
5664   if (VAR_OR_FUNCTION_DECL_P (decl) && DECL_LOCAL_DECL_P (decl))
5665     {
5666       if (!DECL_LANG_SPECIFIC (decl))
5667         /* An unresolved dependent local extern.  */
5668         return true;
5669
5670       DECL_ODR_USED (decl) = 1;
5671       auto alias = DECL_LOCAL_DECL_ALIAS (decl);
5672       if (!alias || alias == error_mark_node)
5673         return true;
5674
5675       /* Process the underlying decl.  */
5676       decl = alias;
5677       TREE_USED (decl) = true;
5678     }
5679
5680   cp_warn_deprecated_use (decl, complain);
5681
5682   /* We can only check DECL_ODR_USED on variables or functions with
5683      DECL_LANG_SPECIFIC set, and these are also the only decls that we
5684      might need special handling for.  */
5685   if (!VAR_OR_FUNCTION_DECL_P (decl)
5686       || DECL_LANG_SPECIFIC (decl) == NULL
5687       || DECL_THUNK_P (decl))
5688     {
5689       if (!decl_dependent_p (decl)
5690           && !require_deduced_type (decl, complain))
5691         return false;
5692       return true;
5693     }
5694
5695   /* We only want to do this processing once.  We don't need to keep trying
5696      to instantiate inline templates, because unit-at-a-time will make sure
5697      we get them compiled before functions that want to inline them.  */
5698   if (DECL_ODR_USED (decl))
5699     return true;
5700
5701   if (flag_concepts && TREE_CODE (decl) == FUNCTION_DECL
5702       && !constraints_satisfied_p (decl))
5703     {
5704       if (complain & tf_error)
5705         {
5706           auto_diagnostic_group d;
5707           error ("use of function %qD with unsatisfied constraints",
5708                  decl);
5709           location_t loc = DECL_SOURCE_LOCATION (decl);
5710           inform (loc, "declared here");
5711           diagnose_constraints (loc, decl, NULL_TREE);
5712         }
5713       return false;
5714     }
5715
5716   /* Normally, we can wait until instantiation-time to synthesize DECL.
5717      However, if DECL is a static data member initialized with a constant
5718      or a constexpr function, we need it right now because a reference to
5719      such a data member or a call to such function is not value-dependent.
5720      For a function that uses auto in the return type, we need to instantiate
5721      it to find out its type.  For OpenMP user defined reductions, we need
5722      them instantiated for reduction clauses which inline them by hand
5723      directly.  */
5724   maybe_instantiate_decl (decl);
5725
5726   if (processing_template_decl || in_template_function ())
5727     return true;
5728
5729   /* Check this too in case we're within instantiate_non_dependent_expr.  */
5730   if (DECL_TEMPLATE_INFO (decl)
5731       && uses_template_parms (DECL_TI_ARGS (decl)))
5732     return true;
5733
5734   if (!require_deduced_type (decl, complain))
5735     return false;
5736
5737   if (builtin_pack_fn_p (decl))
5738     {
5739       error ("use of built-in parameter pack %qD outside of a template",
5740              DECL_NAME (decl));
5741       return false;
5742     }
5743
5744   /* If we don't need a value, then we don't need to synthesize DECL.  */
5745   if (cp_unevaluated_operand || in_discarded_stmt)
5746     return true;
5747
5748   DECL_ODR_USED (decl) = 1;
5749   if (DECL_CLONED_FUNCTION_P (decl))
5750     DECL_ODR_USED (DECL_CLONED_FUNCTION (decl)) = 1;
5751
5752   /* DR 757: A type without linkage shall not be used as the type of a
5753      variable or function with linkage, unless
5754    o the variable or function has extern "C" linkage (7.5 [dcl.link]), or
5755    o the variable or function is not used (3.2 [basic.def.odr]) or is
5756    defined in the same translation unit.  */
5757   if (cxx_dialect > cxx98
5758       && decl_linkage (decl) != lk_none
5759       && !DECL_EXTERN_C_P (decl)
5760       && !DECL_ARTIFICIAL (decl)
5761       && !decl_defined_p (decl)
5762       && no_linkage_check (TREE_TYPE (decl), /*relaxed_p=*/false))
5763     vec_safe_push (no_linkage_decls, decl);
5764
5765   if (TREE_CODE (decl) == FUNCTION_DECL
5766       && DECL_DECLARED_INLINE_P (decl)
5767       && !DECL_INITIAL (decl)
5768       && !DECL_ARTIFICIAL (decl)
5769       && !DECL_PURE_VIRTUAL_P (decl))
5770     /* Remember it, so we can check it was defined.  */
5771     note_vague_linkage_fn (decl);
5772
5773   /* Is it a synthesized method that needs to be synthesized?  */
5774   if (TREE_CODE (decl) == FUNCTION_DECL
5775       && DECL_DEFAULTED_FN (decl)
5776       /* A function defaulted outside the class is synthesized either by
5777          cp_finish_decl or instantiate_decl.  */
5778       && !DECL_DEFAULTED_OUTSIDE_CLASS_P (decl)
5779       && ! DECL_INITIAL (decl))
5780     {
5781       /* Defer virtual destructors so that thunks get the right
5782          linkage.  */
5783       if (DECL_VIRTUAL_P (decl) && !at_eof)
5784         {
5785           note_vague_linkage_fn (decl);
5786           return true;
5787         }
5788
5789       /* Remember the current location for a function we will end up
5790          synthesizing.  Then we can inform the user where it was
5791          required in the case of error.  */
5792       if (decl_remember_implicit_trigger_p (decl))
5793         DECL_SOURCE_LOCATION (decl) = input_location;
5794
5795       /* Synthesizing an implicitly defined member function will result in
5796          garbage collection.  We must treat this situation as if we were
5797          within the body of a function so as to avoid collecting live data
5798          on the stack (such as overload resolution candidates).
5799
5800          We could just let c_parse_final_cleanups handle synthesizing
5801          this function by adding it to deferred_fns, but doing
5802          it at the use site produces better error messages.  */
5803       ++function_depth;
5804       synthesize_method (decl);
5805       --function_depth;
5806       /* If this is a synthesized method we don't need to
5807          do the instantiation test below.  */
5808     }
5809   else if (VAR_OR_FUNCTION_DECL_P (decl)
5810            && DECL_TEMPLATE_INFO (decl)
5811            && !DECL_DECLARED_CONCEPT_P (decl)
5812            && (!DECL_EXPLICIT_INSTANTIATION (decl)
5813                || always_instantiate_p (decl)))
5814     /* If this is a function or variable that is an instance of some
5815        template, we now know that we will need to actually do the
5816        instantiation. We check that DECL is not an explicit
5817        instantiation because that is not checked in instantiate_decl.
5818
5819        We put off instantiating functions in order to improve compile
5820        times.  Maintaining a stack of active functions is expensive,
5821        and the inliner knows to instantiate any functions it might
5822        need.  Therefore, we always try to defer instantiation.  */
5823     {
5824       ++function_depth;
5825       instantiate_decl (decl, /*defer_ok=*/true,
5826                         /*expl_inst_class_mem_p=*/false);
5827       --function_depth;
5828     }
5829
5830   return true;
5831 }
5832
5833 bool
5834 mark_used (tree decl)
5835 {
5836   return mark_used (decl, tf_warning_or_error);
5837 }
5838
5839 tree
5840 vtv_start_verification_constructor_init_function (void)
5841 {
5842   return start_objects ('I', MAX_RESERVED_INIT_PRIORITY - 1);
5843 }
5844
5845 tree
5846 vtv_finish_verification_constructor_init_function (tree function_body)
5847 {
5848   tree fn;
5849
5850   finish_compound_stmt (function_body);
5851   fn = finish_function (/*inline_p=*/false);
5852   DECL_STATIC_CONSTRUCTOR (fn) = 1;
5853   decl_init_priority_insert (fn, MAX_RESERVED_INIT_PRIORITY - 1);
5854
5855   return fn;
5856 }
5857
5858 #include "gt-cp-decl2.h"