gcc/cp/decl2.cc

/* Process declarations and variables for C++ compiler.
   Copyright (C) 1988-2022 Free Software Foundation, Inc.
   Hacked by Michael Tiemann (tiemann@cygnus.com)

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */


/* Process declarations and symbol lookup for C++ front end.
   Also constructs types; the standard scalar types at initialization,
   and structure, union, array and enum types when they are declared.  */

/* ??? not all decl nodes are given the most useful possible
   line numbers.  For example, the CONST_DECLs for enum values.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "memmodel.h"
#include "target.h"
#include "cp-tree.h"
#include "c-family/c-common.h"
#include "timevar.h"
#include "stringpool.h"
#include "cgraph.h"
#include "varasm.h"
#include "attribs.h"
#include "stor-layout.h"
#include "calls.h"
#include "decl.h"
#include "toplev.h"
#include "c-family/c-objc.h"
#include "c-family/c-pragma.h"
#include "dumpfile.h"
#include "intl.h"
#include "c-family/c-ada-spec.h"
#include "asan.h"
#include "optabs-query.h"

/* Id for dumping the raw trees.  */
int raw_dump_id;
 
extern cpp_reader *parse_in;

/* This structure contains information about the initializations
   and/or destructions required for a particular priority level.  */
typedef struct priority_info_s {
  /* Nonzero if there have been any initializations at this priority
     throughout the translation unit.  */
  int initializations_p;
  /* Nonzero if there have been any destructions at this priority
     throughout the translation unit.  */
  int destructions_p;
} *priority_info;

static tree start_objects (int, int);
static void finish_objects (int, int, tree);
static tree start_static_storage_duration_function (unsigned);
static void finish_static_storage_duration_function (tree);
static priority_info get_priority_info (int);
static void do_static_initialization_or_destruction (tree, bool);
static void one_static_initialization_or_destruction (tree, tree, bool);
static void generate_ctor_or_dtor_function (bool, int, location_t *);
static int generate_ctor_and_dtor_functions_for_priority (splay_tree_node,
							  void *);
static tree prune_vars_needing_no_initialization (tree *);
static void write_out_vars (tree);
static void import_export_class (tree);
static tree get_guard_bits (tree);
static void determine_visibility_from_class (tree, tree);
static bool determine_hidden_inline (tree);

/* A list of static class variables.  This is needed, because a
   static class variable can be declared inside the class without
   an initializer, and then initialized, statically, outside the class.  */
static GTY(()) vec<tree, va_gc> *pending_statics;

/* A list of functions which were declared inline, but which we
   may need to emit outline anyway.  */
static GTY(()) vec<tree, va_gc> *deferred_fns;

/* A list of decls that use types with no linkage, which we need to make
   sure are defined.  */
static GTY(()) vec<tree, va_gc> *no_linkage_decls;

/* A vector of alternating decls and identifiers, where the latter
   is to be an alias for the former if the former is defined.  */
static GTY(()) vec<tree, va_gc> *mangling_aliases;

/* hash traits for declarations.  Hashes single decls via
   DECL_ASSEMBLER_NAME_RAW.  */

struct mangled_decl_hash : ggc_remove <tree>
{
  typedef tree value_type; /* A DECL.  */
  typedef tree compare_type; /* An identifier.  */

  static hashval_t hash (const value_type decl)
  {
    return IDENTIFIER_HASH_VALUE (DECL_ASSEMBLER_NAME_RAW (decl));
  }
  static bool equal (const value_type existing, compare_type candidate)
  {
    tree name = DECL_ASSEMBLER_NAME_RAW (existing);
    return candidate == name;
  }

  static const bool empty_zero_p = true;
  static inline void mark_empty (value_type &p) {p = NULL_TREE;}
  static inline bool is_empty (value_type p) {return !p;}

  static bool is_deleted (value_type e)
  {
    return e == reinterpret_cast <value_type> (1);
  }
  static void mark_deleted (value_type &e)
  {
    e = reinterpret_cast <value_type> (1);
  }
};

/* A hash table of decls keyed by mangled name.  Used to figure out if
   we need compatibility aliases.  */
static GTY(()) hash_table<mangled_decl_hash> *mangled_decls;

/* Nonzero if we're done parsing and into end-of-file activities.  */

int at_eof;

/* True if note_mangling_alias should enqueue mangling aliases for
   later generation, rather than emitting them right away.  */

bool defer_mangling_aliases = true;


/* Return a member function type (a METHOD_TYPE), given FNTYPE (a
   FUNCTION_TYPE), CTYPE (class type), and QUALS (the cv-qualifiers
   that apply to the function).  */

tree
build_memfn_type (tree fntype, tree ctype, cp_cv_quals quals,
		  cp_ref_qualifier rqual)
{
  if (fntype == error_mark_node || ctype == error_mark_node)
    return error_mark_node;

  gcc_assert (FUNC_OR_METHOD_TYPE_P (fntype));

  cp_cv_quals type_quals = quals & ~TYPE_QUAL_RESTRICT;
  ctype = cp_build_qualified_type (ctype, type_quals);

  tree newtype
    = build_method_type_directly (ctype, TREE_TYPE (fntype),
				  (TREE_CODE (fntype) == METHOD_TYPE
				   ? TREE_CHAIN (TYPE_ARG_TYPES (fntype))
				   : TYPE_ARG_TYPES (fntype)));
  if (tree attrs = TYPE_ATTRIBUTES (fntype))
    newtype = cp_build_type_attribute_variant (newtype, attrs);
  newtype = build_cp_fntype_variant (newtype, rqual,
				     TYPE_RAISES_EXCEPTIONS (fntype),
				     TYPE_HAS_LATE_RETURN_TYPE (fntype));

  return newtype;
}

/* Return a variant of FNTYPE, a FUNCTION_TYPE or METHOD_TYPE, with its
   return type changed to NEW_RET.  */

tree
change_return_type (tree new_ret, tree fntype)
{
  if (new_ret == error_mark_node)
    return fntype;

  if (same_type_p (new_ret, TREE_TYPE (fntype)))
    return fntype;

  tree newtype;
  tree args = TYPE_ARG_TYPES (fntype);

  if (TREE_CODE (fntype) == FUNCTION_TYPE)
    {
      newtype = build_function_type (new_ret, args);
      newtype = apply_memfn_quals (newtype,
				   type_memfn_quals (fntype));
    }
  else
    newtype = build_method_type_directly
      (class_of_this_parm (fntype), new_ret, TREE_CHAIN (args));

  if (tree attrs = TYPE_ATTRIBUTES (fntype))
    newtype = cp_build_type_attribute_variant (newtype, attrs);
  newtype = cxx_copy_lang_qualifiers (newtype, fntype);

  return newtype;
}

/* Build a PARM_DECL of FN with NAME and TYPE, and set DECL_ARG_TYPE
   appropriately.  */

tree
cp_build_parm_decl (tree fn, tree name, tree type)
{
  tree parm = build_decl (input_location,
			  PARM_DECL, name, type);
  DECL_CONTEXT (parm) = fn;

  /* DECL_ARG_TYPE is only used by the back end and the back end never
     sees templates.  */
  if (!processing_template_decl)
    DECL_ARG_TYPE (parm) = type_passed_as (type);

  return parm;
}

/* Returns a PARM_DECL of FN for a parameter of the indicated TYPE, with the
   indicated NAME.  */

tree
build_artificial_parm (tree fn, tree name, tree type)
{
  tree parm = cp_build_parm_decl (fn, name, type);
  DECL_ARTIFICIAL (parm) = 1;
  /* All our artificial parms are implicitly `const'; they cannot be
     assigned to.  */
  TREE_READONLY (parm) = 1;
  return parm;
}

/* Constructors for types with virtual baseclasses need an "in-charge" flag
   saying whether this constructor is responsible for initialization of
   virtual baseclasses or not.  All destructors also need this "in-charge"
   flag, which additionally determines whether or not the destructor should
   free the memory for the object.

   This function adds the "in-charge" flag to member function FN if
   appropriate.  It is called from grokclassfn and tsubst.
   FN must be either a constructor or destructor.

   The in-charge flag follows the 'this' parameter, and is followed by the
   VTT parm (if any), then the user-written parms.  */

void
maybe_retrofit_in_chrg (tree fn)
{
  tree basetype, arg_types, parms, parm, fntype;

  /* If we've already add the in-charge parameter don't do it again.  */
  if (DECL_HAS_IN_CHARGE_PARM_P (fn))
    return;

  /* When processing templates we can't know, in general, whether or
     not we're going to have virtual baseclasses.  */
  if (processing_template_decl)
    return;

  /* We don't need an in-charge parameter for constructors that don't
     have virtual bases.  */
  if (DECL_CONSTRUCTOR_P (fn)
      && !CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fn)))
    return;

  arg_types = TYPE_ARG_TYPES (TREE_TYPE (fn));
  basetype = TREE_TYPE (TREE_VALUE (arg_types));
  arg_types = TREE_CHAIN (arg_types);

  parms = DECL_CHAIN (DECL_ARGUMENTS (fn));

  /* If this is a subobject constructor or destructor, our caller will
     pass us a pointer to our VTT.  */
  if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fn)))
    {
      parm = build_artificial_parm (fn, vtt_parm_identifier, vtt_parm_type);

      /* First add it to DECL_ARGUMENTS between 'this' and the real args...  */
      DECL_CHAIN (parm) = parms;
      parms = parm;

      /* ...and then to TYPE_ARG_TYPES.  */
      arg_types = hash_tree_chain (vtt_parm_type, arg_types);

      DECL_HAS_VTT_PARM_P (fn) = 1;
    }

  /* Then add the in-charge parm (before the VTT parm).  */
  parm = build_artificial_parm (fn, in_charge_identifier, integer_type_node);
  DECL_CHAIN (parm) = parms;
  parms = parm;
  arg_types = hash_tree_chain (integer_type_node, arg_types);

  /* Insert our new parameter(s) into the list.  */
  DECL_CHAIN (DECL_ARGUMENTS (fn)) = parms;

  /* And rebuild the function type.  */
  fntype = build_method_type_directly (basetype, TREE_TYPE (TREE_TYPE (fn)),
				       arg_types);
  if (TYPE_ATTRIBUTES (TREE_TYPE (fn)))
    fntype = (cp_build_type_attribute_variant
	      (fntype, TYPE_ATTRIBUTES (TREE_TYPE (fn))));
  fntype = cxx_copy_lang_qualifiers (fntype, TREE_TYPE (fn));
  TREE_TYPE (fn) = fntype;

  /* Now we've got the in-charge parameter.  */
  DECL_HAS_IN_CHARGE_PARM_P (fn) = 1;
}

/* Classes overload their constituent function names automatically.
   When a function name is declared in a record structure,
   its name is changed to it overloaded name.  Since names for
   constructors and destructors can conflict, we place a leading
   '$' for destructors.

   CNAME is the name of the class we are grokking for.

   FUNCTION is a FUNCTION_DECL.  It was created by `grokdeclarator'.

   FLAGS contains bits saying what's special about today's
   arguments.  DTOR_FLAG == DESTRUCTOR.

   If FUNCTION is a destructor, then we must add the `auto-delete' field
   as a second parameter.  There is some hair associated with the fact
   that we must "declare" this variable in the manner consistent with the
   way the rest of the arguments were declared.

   QUALS are the qualifiers for the this pointer.  */

void
grokclassfn (tree ctype, tree function, enum overload_flags flags)
{
  tree fn_name = DECL_NAME (function);

  /* Even within an `extern "C"' block, members get C++ linkage.  See
     [dcl.link] for details.  */
  SET_DECL_LANGUAGE (function, lang_cplusplus);

  if (fn_name == NULL_TREE)
    {
      error ("name missing for member function");
      fn_name = get_identifier ("<anonymous>");
      DECL_NAME (function) = fn_name;
    }

  DECL_CONTEXT (function) = ctype;

  if (flags == DTOR_FLAG)
    DECL_CXX_DESTRUCTOR_P (function) = 1;

  if (flags == DTOR_FLAG || DECL_CONSTRUCTOR_P (function))
    maybe_retrofit_in_chrg (function);
}

/* Create an ARRAY_REF, checking for the user doing things backwards
   along the way.
   If INDEX_EXP is non-NULL, then that is the index expression,
   otherwise INDEX_EXP_LIST is the list of index expressions.  */

tree
grok_array_decl (location_t loc, tree array_expr, tree index_exp,
		 vec<tree, va_gc> **index_exp_list, tsubst_flags_t complain)
{
  tree type;
  tree expr;
  tree orig_array_expr = array_expr;
  tree orig_index_exp = index_exp;
  vec<tree, va_gc> *orig_index_exp_list
    = index_exp_list ? *index_exp_list : NULL;
  tree overload = NULL_TREE;

  if (error_operand_p (array_expr) || error_operand_p (index_exp))
    return error_mark_node;

  if (processing_template_decl)
    {
      if (type_dependent_expression_p (array_expr)
	  || (index_exp ? type_dependent_expression_p (index_exp)
			: any_type_dependent_arguments_p (*index_exp_list)))
	{
	  if (index_exp == NULL)
	    index_exp = build_min_nt_call_vec (ovl_op_identifier (ARRAY_REF),
					       *index_exp_list);
	  return build_min_nt_loc (loc, ARRAY_REF, array_expr, index_exp,
				   NULL_TREE, NULL_TREE);
	}
      array_expr = build_non_dependent_expr (array_expr);
      if (index_exp)
	index_exp = build_non_dependent_expr (index_exp);
      else
	{
	  orig_index_exp_list = make_tree_vector_copy (*index_exp_list);
	  make_args_non_dependent (*index_exp_list);
	}
    }

  type = TREE_TYPE (array_expr);
  gcc_assert (type);
  type = non_reference (type);

  /* If they have an `operator[]', use that.  */
  if (MAYBE_CLASS_TYPE_P (type)
      || (index_exp && MAYBE_CLASS_TYPE_P (TREE_TYPE (index_exp)))
      || (index_exp == NULL_TREE
	  && !(*index_exp_list)->is_empty ()
	  && MAYBE_CLASS_TYPE_P (TREE_TYPE ((*index_exp_list)->last ()))))
    {
      if (index_exp)
	expr = build_new_op (loc, ARRAY_REF, LOOKUP_NORMAL, array_expr,
			     index_exp, NULL_TREE, NULL_TREE,
			     &overload, complain);
      else if ((*index_exp_list)->is_empty ())
	expr = build_op_subscript (loc, array_expr, index_exp_list, &overload,
				   complain);
      else
	{
	  expr = build_op_subscript (loc, array_expr, index_exp_list,
				     &overload, complain & tf_decltype);
	  if (expr == error_mark_node)
	    {
	      tree idx = build_x_compound_expr_from_vec (*index_exp_list, NULL,
							 tf_none);
	      if (idx != error_mark_node)
		expr = build_new_op (loc, ARRAY_REF, LOOKUP_NORMAL, array_expr,
				     idx, NULL_TREE, NULL_TREE, &overload,
				     complain & tf_decltype);
	      if (expr == error_mark_node)
		{
		  overload = NULL_TREE;
		  expr = build_op_subscript (loc, array_expr, index_exp_list,
					     &overload, complain);
		}
	      else
		/* If it would be valid albeit deprecated expression in C++20,
		   just pedwarn on it and treat it as if wrapped in ().  */
		pedwarn (loc, OPT_Wcomma_subscript,
			 "top-level comma expression in array subscript "
			 "changed meaning in C++23");
	    }
	}
    }
  else
    {
      tree p1, p2, i1, i2;
      bool swapped = false;

      /* Otherwise, create an ARRAY_REF for a pointer or array type.
	 It is a little-known fact that, if `a' is an array and `i' is
	 an int, you can write `i[a]', which means the same thing as
	 `a[i]'.  */
      if (TREE_CODE (type) == ARRAY_TYPE || VECTOR_TYPE_P (type))
	p1 = array_expr;
      else
	p1 = build_expr_type_conversion (WANT_POINTER, array_expr, false);

      if (index_exp == NULL_TREE)
	{
	  if ((*index_exp_list)->is_empty ())
	    {
	      error_at (loc, "built-in subscript operator without expression "
			     "list");
	      return error_mark_node;
	    }
	  tree idx = build_x_compound_expr_from_vec (*index_exp_list, NULL,
						     tf_none);
	  if (idx != error_mark_node)
	    /* If it would be valid albeit deprecated expression in C++20,
	       just pedwarn on it and treat it as if wrapped in ().  */
	    pedwarn (loc, OPT_Wcomma_subscript,
		     "top-level comma expression in array subscript "
		     "changed meaning in C++23");
	  else
	    {
	      error_at (loc, "built-in subscript operator with more than one "
			     "expression in expression list");
	      return error_mark_node;
	    }
	  index_exp = idx;
	}

      if (TREE_CODE (TREE_TYPE (index_exp)) == ARRAY_TYPE)
	p2 = index_exp;
      else
	p2 = build_expr_type_conversion (WANT_POINTER, index_exp, false);

      i1 = build_expr_type_conversion (WANT_INT | WANT_ENUM, array_expr,
				       false);
      i2 = build_expr_type_conversion (WANT_INT | WANT_ENUM, index_exp,
				       false);

      if ((p1 && i2) && (i1 && p2))
	error ("ambiguous conversion for array subscript");

      if (p1 && i2)
	array_expr = p1, index_exp = i2;
      else if (i1 && p2)
	swapped = true, array_expr = p2, index_exp = i1;
      else
	{
	  error_at (loc, "invalid types %<%T[%T]%> for array subscript",
		    type, TREE_TYPE (index_exp));
	  return error_mark_node;
	}

      if (array_expr == error_mark_node || index_exp == error_mark_node)
	error ("ambiguous conversion for array subscript");

      if (TYPE_PTR_P (TREE_TYPE (array_expr)))
	array_expr = mark_rvalue_use (array_expr);
      else
	array_expr = mark_lvalue_use_nonread (array_expr);
      index_exp = mark_rvalue_use (index_exp);
      if (swapped
	  && flag_strong_eval_order == 2
	  && (TREE_SIDE_EFFECTS (array_expr) || TREE_SIDE_EFFECTS (index_exp)))
	expr = build_array_ref (input_location, index_exp, array_expr);
      else
	expr = build_array_ref (input_location, array_expr, index_exp);
    }
  if (processing_template_decl && expr != error_mark_node)
    {
      if (overload != NULL_TREE)
	{
	  if (orig_index_exp == NULL_TREE)
	    {
	      expr = build_min_non_dep_op_overload (expr, overload,
						    orig_array_expr,
						    orig_index_exp_list);
	      release_tree_vector (orig_index_exp_list);
	      return expr;
	    }
	  return build_min_non_dep_op_overload (ARRAY_REF, expr, overload,
						orig_array_expr,
						orig_index_exp);
	}

      if (orig_index_exp == NULL_TREE)
	{
	  orig_index_exp
	    = build_min_nt_call_vec (ovl_op_identifier (ARRAY_REF),
				     orig_index_exp_list);
	  release_tree_vector (orig_index_exp_list);
	}

      return build_min_non_dep (ARRAY_REF, expr, orig_array_expr,
				orig_index_exp, NULL_TREE, NULL_TREE);
    }
  return expr;
}

/* Given the cast expression EXP, checking out its validity.   Either return
   an error_mark_node if there was an unavoidable error, return a cast to
   void for trying to delete a pointer w/ the value 0, or return the
   call to delete.  If DOING_VEC is true, we handle things differently
   for doing an array delete.
   Implements ARM $5.3.4.  This is called from the parser.  */

tree
delete_sanity (location_t loc, tree exp, tree size, bool doing_vec,
	       int use_global_delete, tsubst_flags_t complain)
{
  tree t, type;

  if (exp == error_mark_node)
    return exp;

  if (processing_template_decl)
    {
      t = build_min (DELETE_EXPR, void_type_node, exp, size);
      DELETE_EXPR_USE_GLOBAL (t) = use_global_delete;
      DELETE_EXPR_USE_VEC (t) = doing_vec;
      TREE_SIDE_EFFECTS (t) = 1;
      SET_EXPR_LOCATION (t, loc);
      return t;
    }

  location_t exp_loc = cp_expr_loc_or_loc (exp, loc);

  /* An array can't have been allocated by new, so complain.  */
  if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE
      && (complain & tf_warning))
    warning_at (exp_loc, 0, "deleting array %q#E", exp);

  t = build_expr_type_conversion (WANT_POINTER, exp, true);

  if (t == NULL_TREE || t == error_mark_node)
    {
      if (complain & tf_error)
	error_at (exp_loc,
		  "type %q#T argument given to %<delete%>, expected pointer",
		  TREE_TYPE (exp));
      return error_mark_node;
    }

  type = TREE_TYPE (t);

  /* As of Valley Forge, you can delete a pointer to const.  */

  /* You can't delete functions.  */
  if (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
    {
      if (complain & tf_error)
	error_at (exp_loc,
		  "cannot delete a function.  Only pointer-to-objects are "
		  "valid arguments to %<delete%>");
      return error_mark_node;
    }

  /* Deleting ptr to void is undefined behavior [expr.delete/3].  */
  if (VOID_TYPE_P (TREE_TYPE (type)))
    {
      if (complain & tf_warning)
	warning_at (exp_loc, OPT_Wdelete_incomplete,
		    "deleting %qT is undefined", type);
      doing_vec = 0;
    }

  /* Deleting a pointer with the value zero is valid and has no effect.  */
  if (integer_zerop (t))
    return build1_loc (loc, NOP_EXPR, void_type_node, t);

  if (doing_vec)
    return build_vec_delete (loc, t, /*maxindex=*/NULL_TREE,
			     sfk_deleting_destructor,
			     use_global_delete, complain);
  else
    return build_delete (loc, type, t, sfk_deleting_destructor,
			 LOOKUP_NORMAL, use_global_delete,
			 complain);
}

/* Report an error if the indicated template declaration is not the
   sort of thing that should be a member template.  */

void
check_member_template (tree tmpl)
{
  tree decl;

  gcc_assert (TREE_CODE (tmpl) == TEMPLATE_DECL);
  decl = DECL_TEMPLATE_RESULT (tmpl);

  if (TREE_CODE (decl) == FUNCTION_DECL
      || DECL_ALIAS_TEMPLATE_P (tmpl)
      || (TREE_CODE (decl) == TYPE_DECL
	  && MAYBE_CLASS_TYPE_P (TREE_TYPE (decl))))
    {
      /* The parser rejects template declarations in local classes
	 (with the exception of generic lambdas).  */
      gcc_assert (!current_function_decl || LAMBDA_FUNCTION_P (decl));
      /* The parser rejects any use of virtual in a function template.  */
      gcc_assert (!(TREE_CODE (decl) == FUNCTION_DECL
		    && DECL_VIRTUAL_P (decl)));

      /* The debug-information generating code doesn't know what to do
	 with member templates.  */
      DECL_IGNORED_P (tmpl) = 1;
    }
  else if (variable_template_p (tmpl))
    /* OK */;
  else
    error ("template declaration of %q#D", decl);
}

/* Sanity check: report error if this function FUNCTION is not
   really a member of the class (CTYPE) it is supposed to belong to.
   TEMPLATE_PARMS is used to specify the template parameters of a member
   template passed as FUNCTION_DECL. If the member template is passed as a
   TEMPLATE_DECL, it can be NULL since the parameters can be extracted
   from the declaration. If the function is not a function template, it
   must be NULL.
   It returns the original declaration for the function, NULL_TREE if
   no declaration was found, error_mark_node if an error was emitted.  */

tree
check_classfn (tree ctype, tree function, tree template_parms)
{
  if (DECL_USE_TEMPLATE (function)
      && !(TREE_CODE (function) == TEMPLATE_DECL
	   && DECL_TEMPLATE_SPECIALIZATION (function))
      && DECL_MEMBER_TEMPLATE_P (DECL_TI_TEMPLATE (function)))
    /* Since this is a specialization of a member template,
       we're not going to find the declaration in the class.
       For example, in:

	 struct S { template <typename T> void f(T); };
	 template <> void S::f(int);

       we're not going to find `S::f(int)', but there's no
       reason we should, either.  We let our callers know we didn't
       find the method, but we don't complain.  */
    return NULL_TREE;

  /* Basic sanity check: for a template function, the template parameters
     either were not passed, or they are the same of DECL_TEMPLATE_PARMS.  */
  if (TREE_CODE (function) == TEMPLATE_DECL)
    {
      if (template_parms
	  && !comp_template_parms (template_parms,
				   DECL_TEMPLATE_PARMS (function)))
	{
	  error ("template parameter lists provided don%'t match the "
		 "template parameters of %qD", function);
	  return error_mark_node;
	}
      template_parms = DECL_TEMPLATE_PARMS (function);
    }

  /* OK, is this a definition of a member template?  */
  bool is_template = (template_parms != NULL_TREE);

  /* [temp.mem]

     A destructor shall not be a member template.  */
  if (DECL_DESTRUCTOR_P (function) && is_template)
    {
      error ("destructor %qD declared as member template", function);
      return error_mark_node;
    }

  /* We must enter the scope here, because conversion operators are
     named by target type, and type equivalence relies on typenames
     resolving within the scope of CTYPE.  */
  tree pushed_scope = push_scope (ctype);
  tree matched = NULL_TREE;
  tree fns = get_class_binding (ctype, DECL_NAME (function));
  bool saw_template = false;

  for (ovl_iterator iter (fns); !matched && iter; ++iter)
    {
      tree fndecl = *iter;

      if (TREE_CODE (fndecl) == TEMPLATE_DECL)
	saw_template = true;

      /* A member template definition only matches a member template
	 declaration.  */
      if (is_template != (TREE_CODE (fndecl) == TEMPLATE_DECL))
	continue;

      if (!DECL_DECLARES_FUNCTION_P (fndecl))
	continue;

      tree p1 = TYPE_ARG_TYPES (TREE_TYPE (function));
      tree p2 = TYPE_ARG_TYPES (TREE_TYPE (fndecl));

      /* We cannot simply call decls_match because this doesn't work
	 for static member functions that are pretending to be
	 methods, and because the name may have been changed by
	 asm("new_name").  */

      /* Get rid of the this parameter on functions that become
	 static.  */
      if (DECL_STATIC_FUNCTION_P (fndecl)
	  && TREE_CODE (TREE_TYPE (function)) == METHOD_TYPE)
	p1 = TREE_CHAIN (p1);

      /* ref-qualifier or absence of same must match.  */
      if (type_memfn_rqual (TREE_TYPE (function))
	  != type_memfn_rqual (TREE_TYPE (fndecl)))
	continue;

      // Include constraints in the match.
      tree c1 = get_constraints (function);
      tree c2 = get_constraints (fndecl);

      /* While finding a match, same types and params are not enough
	 if the function is versioned.  Also check version ("target")
	 attributes.  */
      if (same_type_p (TREE_TYPE (TREE_TYPE (function)),
		       TREE_TYPE (TREE_TYPE (fndecl)))
	  && compparms (p1, p2)
	  && !targetm.target_option.function_versions (function, fndecl)
	  && (!is_template
	      || comp_template_parms (template_parms,
				      DECL_TEMPLATE_PARMS (fndecl)))
	  && equivalent_constraints (c1, c2)
	  && (DECL_TEMPLATE_SPECIALIZATION (function)
	      == DECL_TEMPLATE_SPECIALIZATION (fndecl))
	  && (!DECL_TEMPLATE_SPECIALIZATION (function)
	      || (DECL_TI_TEMPLATE (function) == DECL_TI_TEMPLATE (fndecl))))
	matched = fndecl;
    }

  if (!matched && !is_template && saw_template
      && !processing_template_decl && DECL_UNIQUE_FRIEND_P (function))
    {
      /* "[if no non-template match is found,] each remaining function template
	 is replaced with the specialization chosen by deduction from the
	 friend declaration or discarded if deduction fails."

	 So ask check_explicit_specialization to find a matching template.  */
      SET_DECL_IMPLICIT_INSTANTIATION (function);
      tree spec = check_explicit_specialization (DECL_NAME (function),
						 function, /* tcount */0,
						 /* friend flag */4,
						 /* attrlist */NULL_TREE);
      if (spec != error_mark_node)
	matched = spec;
    }

  if (!matched)
    {
      if (!COMPLETE_TYPE_P (ctype))
	cxx_incomplete_type_error (DECL_SOURCE_LOCATION (function),
				   function, ctype);
      else
	{
	  if (DECL_CONV_FN_P (function))
	    fns = get_class_binding (ctype, conv_op_identifier);

	  error_at (DECL_SOURCE_LOCATION (function),
		    "no declaration matches %q#D", function);
	  if (fns)
	    print_candidates (fns);
	  else if (DECL_CONV_FN_P (function))
	    inform (DECL_SOURCE_LOCATION (function),
		    "no conversion operators declared");
	  else
	    inform (DECL_SOURCE_LOCATION (function),
		    "no functions named %qD", function);
	  inform (DECL_SOURCE_LOCATION (TYPE_NAME (ctype)),
		  "%#qT defined here", ctype);
	}
      matched = error_mark_node;
    }

  if (pushed_scope)
    pop_scope (pushed_scope);

  return matched;
}

/* DECL is a function with vague linkage.  Remember it so that at the
   end of the translation unit we can decide whether or not to emit
   it.  */

void
note_vague_linkage_fn (tree decl)
{
  if (processing_template_decl)
    return;

  DECL_DEFER_OUTPUT (decl) = 1;
  vec_safe_push (deferred_fns, decl);
}

/* As above, but for variable template instantiations.  */

void
note_variable_template_instantiation (tree decl)
{
  vec_safe_push (pending_statics, decl);
}

/* We have just processed the DECL, which is a static data member.
   The other parameters are as for cp_finish_decl.  */

void
finish_static_data_member_decl (tree decl,
				tree init, bool init_const_expr_p,
				tree asmspec_tree,
				int flags)
{
  if (DECL_TEMPLATE_INSTANTIATED (decl))
    /* We already needed to instantiate this, so the processing in this
       function is unnecessary/wrong.  */
    return;

  DECL_CONTEXT (decl) = current_class_type;

  /* We cannot call pushdecl here, because that would fill in the
     TREE_CHAIN of our decl.  Instead, we modify cp_finish_decl to do
     the right thing, namely, to put this decl out straight away.  */

  if (! processing_template_decl)
    vec_safe_push (pending_statics, decl);

  if (LOCAL_CLASS_P (current_class_type)
      /* We already complained about the template definition.  */
      && !DECL_TEMPLATE_INSTANTIATION (decl))
    permerror (DECL_SOURCE_LOCATION (decl),
	       "local class %q#T shall not have static data member %q#D",
	       current_class_type, decl);
  else
    for (tree t = current_class_type; TYPE_P (t);
	 t = CP_TYPE_CONTEXT (t))
      if (TYPE_UNNAMED_P (t))
	{
	  auto_diagnostic_group d;
	  if (permerror (DECL_SOURCE_LOCATION (decl),
			 "static data member %qD in unnamed class", decl))
	    inform (DECL_SOURCE_LOCATION (TYPE_NAME (t)),
		    "unnamed class defined here");
	  break;
	}

  if (DECL_INLINE_VAR_P (decl) && !DECL_TEMPLATE_INSTANTIATION (decl))
    /* An inline variable is immediately defined, so don't set DECL_IN_AGGR_P.
       Except that if decl is a template instantiation, it isn't defined until
       instantiate_decl.  */;
  else
    DECL_IN_AGGR_P (decl) = 1;

  if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
      && TYPE_DOMAIN (TREE_TYPE (decl)) == NULL_TREE)
    SET_VAR_HAD_UNKNOWN_BOUND (decl);

  if (init)
    {
      /* Similarly to start_decl_1, we want to complete the type in order
	 to do the right thing in cp_apply_type_quals_to_decl, possibly
	 clear TYPE_QUAL_CONST (c++/65579).  */
      tree type = TREE_TYPE (decl) = complete_type (TREE_TYPE (decl));
      cp_apply_type_quals_to_decl (cp_type_quals (type), decl);
    }

  cp_finish_decl (decl, init, init_const_expr_p, asmspec_tree, flags);
}

/* DECLARATOR and DECLSPECS correspond to a class member.  The other
   parameters are as for cp_finish_decl.  Return the DECL for the
   class member declared.  */

tree
grokfield (const cp_declarator *declarator,
	   cp_decl_specifier_seq *declspecs,
	   tree init, bool init_const_expr_p,
	   tree asmspec_tree,
	   tree attrlist)
{
  tree value;
  const char *asmspec = 0;
  int flags;

  if (init
      && TREE_CODE (init) == TREE_LIST
      && TREE_VALUE (init) == error_mark_node
      && TREE_CHAIN (init) == NULL_TREE)
    init = NULL_TREE;

  int initialized;
  if (init == ridpointers[(int)RID_DELETE])
    initialized = SD_DELETED;
  else if (init == ridpointers[(int)RID_DEFAULT])
    initialized = SD_DEFAULTED;
  else if (init)
    initialized = SD_INITIALIZED;
  else
    initialized = SD_UNINITIALIZED;

  value = grokdeclarator (declarator, declspecs, FIELD, initialized, &attrlist);
  if (! value || value == error_mark_node)
    /* friend or constructor went bad.  */
    return error_mark_node;
  if (TREE_TYPE (value) == error_mark_node)
    return value;

  if (TREE_CODE (value) == TYPE_DECL && init)
    {
      error_at (cp_expr_loc_or_loc (init, DECL_SOURCE_LOCATION (value)),
		"typedef %qD is initialized (use %qs instead)",
		value, "decltype");
      init = NULL_TREE;
    }

  /* Pass friendly classes back.  */
  if (value == void_type_node)
    return value;

  if (DECL_NAME (value)
      && TREE_CODE (DECL_NAME (value)) == TEMPLATE_ID_EXPR)
    {
      error_at (declarator->id_loc,
		"explicit template argument list not allowed");
      return error_mark_node;
    }

  /* Stash away type declarations.  */
  if (TREE_CODE (value) == TYPE_DECL)
    {
      DECL_NONLOCAL (value) = 1;
      DECL_CONTEXT (value) = current_class_type;

      if (attrlist)
	{
	  int attrflags = 0;

	  /* If this is a typedef that names the class for linkage purposes
	     (7.1.3p8), apply any attributes directly to the type.  */
	  if (OVERLOAD_TYPE_P (TREE_TYPE (value))
	      && value == TYPE_NAME (TYPE_MAIN_VARIANT (TREE_TYPE (value))))
	    attrflags = ATTR_FLAG_TYPE_IN_PLACE;

	  cplus_decl_attributes (&value, attrlist, attrflags);
	}

      if (decl_spec_seq_has_spec_p (declspecs, ds_typedef)
          && TREE_TYPE (value) != error_mark_node
          && TYPE_NAME (TYPE_MAIN_VARIANT (TREE_TYPE (value))) != value)
	set_underlying_type (value);

      /* It's important that push_template_decl below follows
	 set_underlying_type above so that the created template
	 carries the properly set type of VALUE.  */
      if (processing_template_decl)
	value = push_template_decl (value);

      record_locally_defined_typedef (value);
      return value;
    }

  int friendp = decl_spec_seq_has_spec_p (declspecs, ds_friend);

  if (!friendp && DECL_IN_AGGR_P (value))
    {
      error ("%qD is already defined in %qT", value, DECL_CONTEXT (value));
      return void_type_node;
    }

  if (asmspec_tree && asmspec_tree != error_mark_node)
    asmspec = TREE_STRING_POINTER (asmspec_tree);

  if (init)
    {
      if (TREE_CODE (value) == FUNCTION_DECL)
	{
	  if (init == ridpointers[(int)RID_DELETE])
	    {
	      DECL_DELETED_FN (value) = 1;
	      DECL_DECLARED_INLINE_P (value) = 1;
	    }
	  else if (init == ridpointers[(int)RID_DEFAULT])
	    {
	      if (defaultable_fn_check (value))
		{
		  DECL_DEFAULTED_FN (value) = 1;
		  DECL_INITIALIZED_IN_CLASS_P (value) = 1;
		  DECL_DECLARED_INLINE_P (value) = 1;
		  /* grokfndecl set this to error_mark_node, but we want to
		     leave it unset until synthesize_method.  */
		  DECL_INITIAL (value) = NULL_TREE;
		}
	    }
	  else if (TREE_CODE (init) == DEFERRED_PARSE)
	    error ("invalid initializer for member function %qD", value);
	  else if (TREE_CODE (TREE_TYPE (value)) == METHOD_TYPE)
	    {
	      if (integer_zerop (init))
		DECL_PURE_VIRTUAL_P (value) = 1;
	      else if (error_operand_p (init))
		; /* An error has already been reported.  */
	      else
		error ("invalid initializer for member function %qD",
		       value);
	    }
	  else
	    {
	      gcc_assert (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE);
	      location_t iloc
		= cp_expr_loc_or_loc (init, DECL_SOURCE_LOCATION (value));
	      if (friendp)
		error_at (iloc, "initializer specified for friend "
			  "function %qD", value);
	      else
		error_at (iloc, "initializer specified for static "
			  "member function %qD", value);
	    }
	}
      else if (TREE_CODE (value) == FIELD_DECL)
	/* C++11 NSDMI, keep going.  */;
      else if (!VAR_P (value))
	gcc_unreachable ();
    }

  /* Pass friend decls back.  */
  if ((TREE_CODE (value) == FUNCTION_DECL
       || TREE_CODE (value) == TEMPLATE_DECL)
      && DECL_CONTEXT (value) != current_class_type)
    {
      if (attrlist)
	cplus_decl_attributes (&value, attrlist, 0);
      return value;
    }

  /* Need to set this before push_template_decl.  */
  if (VAR_P (value))
    DECL_CONTEXT (value) = current_class_type;

  if (processing_template_decl && VAR_OR_FUNCTION_DECL_P (value))
    {
      value = push_template_decl (value);
      if (error_operand_p (value))
	return error_mark_node;
    }

  if (attrlist)
    cplus_decl_attributes (&value, attrlist, 0);

  if (init && DIRECT_LIST_INIT_P (init))
    flags = LOOKUP_NORMAL;
  else
    flags = LOOKUP_IMPLICIT;

  switch (TREE_CODE (value))
    {
    case VAR_DECL:
      finish_static_data_member_decl (value, init, init_const_expr_p,
				      asmspec_tree, flags);
      return value;

    case FIELD_DECL:
      if (asmspec)
	error ("%<asm%> specifiers are not permitted on non-static data members");
      if (DECL_INITIAL (value) == error_mark_node)
	init = error_mark_node;
      cp_finish_decl (value, init, /*init_const_expr_p=*/false,
		      NULL_TREE, flags);
      DECL_IN_AGGR_P (value) = 1;
      return value;

    case  FUNCTION_DECL:
      if (asmspec)
	set_user_assembler_name (value, asmspec);

      cp_finish_decl (value,
		      /*init=*/NULL_TREE,
		      /*init_const_expr_p=*/false,
		      asmspec_tree, flags);

      /* Pass friends back this way.  */
      if (DECL_UNIQUE_FRIEND_P (value))
	return void_type_node;

      DECL_IN_AGGR_P (value) = 1;
      return value;

    default:
      gcc_unreachable ();
    }
  return NULL_TREE;
}

/* Like `grokfield', but for bitfields.
   WIDTH is the width of the bitfield, a constant expression.
   The other parameters are as for grokfield.  */

tree
grokbitfield (const cp_declarator *declarator,
	      cp_decl_specifier_seq *declspecs, tree width, tree init,
	      tree attrlist)
{
  tree value = grokdeclarator (declarator, declspecs, BITFIELD,
			       init != NULL_TREE, &attrlist);

  if (value == error_mark_node)
    return NULL_TREE; /* friends went bad.  */

  tree type = TREE_TYPE (value);
  if (type == error_mark_node)
    return value;

  /* Pass friendly classes back.  */
  if (VOID_TYPE_P (value))
    return void_type_node;

  if (!INTEGRAL_OR_ENUMERATION_TYPE_P (type)
      && (INDIRECT_TYPE_P (type) || !dependent_type_p (type)))
    {
      error_at (DECL_SOURCE_LOCATION (value),
		"bit-field %qD with non-integral type %qT",
		value, type);
      return error_mark_node;
    }

  if (TREE_CODE (value) == TYPE_DECL)
    {
      error_at (DECL_SOURCE_LOCATION (value),
		"cannot declare %qD to be a bit-field type", value);
      return NULL_TREE;
    }

  /* Usually, finish_struct_1 catches bitfields with invalid types.
     But, in the case of bitfields with function type, we confuse
     ourselves into thinking they are member functions, so we must
     check here.  */
  if (TREE_CODE (value) == FUNCTION_DECL)
    {
      error_at (DECL_SOURCE_LOCATION (value),
		"cannot declare bit-field %qD with function type", value);
      return NULL_TREE;
    }

  if (TYPE_WARN_IF_NOT_ALIGN (type))
    {
      error_at (DECL_SOURCE_LOCATION (value), "cannot declare bit-field "
		"%qD with %<warn_if_not_aligned%> type", value);
      return NULL_TREE;
    }

  if (DECL_IN_AGGR_P (value))
    {
      error ("%qD is already defined in the class %qT", value,
	     DECL_CONTEXT (value));
      return void_type_node;
    }

  if (TREE_STATIC (value))
    {
      error_at (DECL_SOURCE_LOCATION (value),
		"static member %qD cannot be a bit-field", value);
      return NULL_TREE;
    }

  int flags = LOOKUP_IMPLICIT;
  if (init && DIRECT_LIST_INIT_P (init))
    flags = LOOKUP_NORMAL;
  cp_finish_decl (value, init, false, NULL_TREE, flags);

  if (width != error_mark_node)
    {
      /* The width must be an integer type.  */
      if (!type_dependent_expression_p (width)
	  && !INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (TREE_TYPE (width)))
	error ("width of bit-field %qD has non-integral type %qT", value,
	       TREE_TYPE (width));
      else if (!check_for_bare_parameter_packs (width))
	{
	  /* Temporarily stash the width in DECL_BIT_FIELD_REPRESENTATIVE.
	     check_bitfield_decl picks it from there later and sets DECL_SIZE
	     accordingly.  */
	  DECL_BIT_FIELD_REPRESENTATIVE (value) = width;
	  SET_DECL_C_BIT_FIELD (value);
	}
    }

  DECL_IN_AGGR_P (value) = 1;

  if (attrlist)
    cplus_decl_attributes (&value, attrlist, /*flags=*/0);

  return value;
}


/* Returns true iff ATTR is an attribute which needs to be applied at
   instantiation time rather than template definition time.  */

static bool
is_late_template_attribute (tree attr, tree decl)
{
  tree name = get_attribute_name (attr);
  tree args = TREE_VALUE (attr);
  const struct attribute_spec *spec = lookup_attribute_spec (name);
  tree arg;

  if (!spec)
    /* Unknown attribute.  */
    return false;

  /* Attribute weak handling wants to write out assembly right away.  */
  if (is_attribute_p ("weak", name))
    return true;

  /* Attributes used and unused are applied directly to typedefs for the
     benefit of maybe_warn_unused_local_typedefs.  */
  if (TREE_CODE (decl) == TYPE_DECL
      && (is_attribute_p ("unused", name)
	  || is_attribute_p ("used", name)))
    return false;

  /* Attribute tls_model wants to modify the symtab.  */
  if (is_attribute_p ("tls_model", name))
    return true;

  /* #pragma omp declare simd attribute needs to be always deferred.  */
  if (flag_openmp
      && is_attribute_p ("omp declare simd", name))
    return true;

  if (args == error_mark_node)
    return false;

  /* An attribute pack is clearly dependent.  */
  if (args && PACK_EXPANSION_P (args))
    return true;

  /* If any of the arguments are dependent expressions, we can't evaluate
     the attribute until instantiation time.  */
  for (arg = args; arg; arg = TREE_CHAIN (arg))
    {
      tree t = TREE_VALUE (arg);

      /* If the first attribute argument is an identifier, only consider
	 second and following arguments.  Attributes like mode, format,
	 cleanup and several target specific attributes aren't late
	 just because they have an IDENTIFIER_NODE as first argument.  */
      if (arg == args && attribute_takes_identifier_p (name)
	  && identifier_p (t))
	continue;

      if (value_dependent_expression_p (t))
	return true;
    }

  if (TREE_CODE (decl) == TYPE_DECL
      || TYPE_P (decl)
      || spec->type_required)
    {
      tree type = TYPE_P (decl) ? decl : TREE_TYPE (decl);

      if (!type)
	return true;

      /* We can't apply any attributes to a completely unknown type until
	 instantiation time.  */
      enum tree_code code = TREE_CODE (type);
      if (code == TEMPLATE_TYPE_PARM
	  || code == BOUND_TEMPLATE_TEMPLATE_PARM
	  || code == TYPENAME_TYPE)
	return true;
      /* Also defer most attributes on dependent types.  This is not
	 necessary in all cases, but is the better default.  */
      else if (dependent_type_p (type)
	       /* But some attributes specifically apply to templates.  */
	       && !is_attribute_p ("abi_tag", name)
	       && !is_attribute_p ("deprecated", name)
	       && !is_attribute_p ("unavailable", name)
	       && !is_attribute_p ("visibility", name))
	return true;
      else
	return false;
    }
  else
    return false;
}

/* ATTR_P is a list of attributes.  Remove any attributes which need to be
   applied at instantiation time and return them.  If IS_DEPENDENT is true,
   the declaration itself is dependent, so all attributes should be applied
   at instantiation time.  */

tree
splice_template_attributes (tree *attr_p, tree decl)
{
  tree *p = attr_p;
  tree late_attrs = NULL_TREE;
  tree *q = &late_attrs;

  if (!p || *p == error_mark_node)
    return NULL_TREE;

  for (; *p; )
    {
      if (is_late_template_attribute (*p, decl))
	{
	  ATTR_IS_DEPENDENT (*p) = 1;
	  *q = *p;
	  *p = TREE_CHAIN (*p);
	  q = &TREE_CHAIN (*q);
	  *q = NULL_TREE;
	}
      else
	p = &TREE_CHAIN (*p);
    }

  return late_attrs;
}

/* Attach any LATE_ATTRS to DECL_P, after the non-dependent attributes have
   been applied by a previous call to decl_attributes.  */

static void
save_template_attributes (tree late_attrs, tree *decl_p, int flags)
{
  tree *q;

  if (!late_attrs)
    return;

  if (DECL_P (*decl_p))
    q = &DECL_ATTRIBUTES (*decl_p);
  else
    q = &TYPE_ATTRIBUTES (*decl_p);

  tree old_attrs = *q;

  /* Place the late attributes at the beginning of the attribute
     list.  */
  late_attrs = chainon (late_attrs, *q);
  if (*q != late_attrs
      && !DECL_P (*decl_p)
      && !(flags & ATTR_FLAG_TYPE_IN_PLACE))
    {
      if (!dependent_type_p (*decl_p))
	*decl_p = cp_build_type_attribute_variant (*decl_p, late_attrs);
      else
	{
	  *decl_p = build_variant_type_copy (*decl_p);
	  TYPE_ATTRIBUTES (*decl_p) = late_attrs;
	}
    }
  else
    *q = late_attrs;

  if (!DECL_P (*decl_p) && *decl_p == TYPE_MAIN_VARIANT (*decl_p))
    {
      /* We've added new attributes directly to the main variant, so
	 now we need to update all of the other variants to include
	 these new attributes.  */
      tree variant;
      for (variant = TYPE_NEXT_VARIANT (*decl_p); variant;
	   variant = TYPE_NEXT_VARIANT (variant))
	{
	  gcc_assert (TYPE_ATTRIBUTES (variant) == old_attrs);
	  TYPE_ATTRIBUTES (variant) = TYPE_ATTRIBUTES (*decl_p);
	}
    }
}

/* True if ATTRS contains any dependent attributes that affect type
   identity.  */

bool
any_dependent_type_attributes_p (tree attrs)
{
  for (tree a = attrs; a; a = TREE_CHAIN (a))
    if (ATTR_IS_DEPENDENT (a))
      {
	const attribute_spec *as = lookup_attribute_spec (TREE_PURPOSE (a));
	if (as && as->affects_type_identity)
	  return true;
      }
  return false;
}

/* Return true iff ATTRS are acceptable attributes to be applied in-place
   to a typedef which gives a previously unnamed class or enum a name for
   linkage purposes.  */

bool
attributes_naming_typedef_ok (tree attrs)
{
  for (; attrs; attrs = TREE_CHAIN (attrs))
    {
      tree name = get_attribute_name (attrs);
      if (is_attribute_p ("vector_size", name))
	return false;
    }
  return true;
}

/* Like reconstruct_complex_type, but handle also template trees.  */

tree
cp_reconstruct_complex_type (tree type, tree bottom)
{
  tree inner, outer;

  if (TYPE_PTR_P (type))
    {
      inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
      outer = build_pointer_type_for_mode (inner, TYPE_MODE (type),
					   TYPE_REF_CAN_ALIAS_ALL (type));
    }
  else if (TYPE_REF_P (type))
    {
      inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
      outer = build_reference_type_for_mode (inner, TYPE_MODE (type),
					     TYPE_REF_CAN_ALIAS_ALL (type));
    }
  else if (TREE_CODE (type) == ARRAY_TYPE)
    {
      inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
      outer = build_cplus_array_type (inner, TYPE_DOMAIN (type));
      /* Don't call cp_build_qualified_type on ARRAY_TYPEs, the
	 element type qualification will be handled by the recursive
	 cp_reconstruct_complex_type call and cp_build_qualified_type
	 for ARRAY_TYPEs changes the element type.  */
      return outer;
    }
  else if (TREE_CODE (type) == FUNCTION_TYPE)
    {
      inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
      outer = build_function_type (inner, TYPE_ARG_TYPES (type));
      outer = apply_memfn_quals (outer, type_memfn_quals (type));
    }
  else if (TREE_CODE (type) == METHOD_TYPE)
    {
      inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
      /* The build_method_type_directly() routine prepends 'this' to argument list,
	 so we must compensate by getting rid of it.  */
      outer
	= build_method_type_directly
	    (class_of_this_parm (type), inner,
	     TREE_CHAIN (TYPE_ARG_TYPES (type)));
    }
  else if (TREE_CODE (type) == OFFSET_TYPE)
    {
      inner = cp_reconstruct_complex_type (TREE_TYPE (type), bottom);
      outer = build_offset_type (TYPE_OFFSET_BASETYPE (type), inner);
    }
  else
    return bottom;

  if (TYPE_ATTRIBUTES (type))
    outer = cp_build_type_attribute_variant (outer, TYPE_ATTRIBUTES (type));
  outer = cp_build_qualified_type (outer, cp_type_quals (type));
  outer = cxx_copy_lang_qualifiers (outer, type);

  return outer;
}

/* Replaces any constexpr expression that may be into the attributes
   arguments with their reduced value.  */

void
cp_check_const_attributes (tree attributes)
{
  if (attributes == error_mark_node)
    return;

  tree attr;
  for (attr = attributes; attr; attr = TREE_CHAIN (attr))
    {
      tree arg;
      /* As we implement alignas using gnu::aligned attribute and
	 alignas argument is a constant expression, force manifestly
	 constant evaluation of aligned attribute argument.  */
      bool manifestly_const_eval
	= is_attribute_p ("aligned", get_attribute_name (attr));
      for (arg = TREE_VALUE (attr); arg && TREE_CODE (arg) == TREE_LIST;
	   arg = TREE_CHAIN (arg))
	{
	  tree expr = TREE_VALUE (arg);
	  if (EXPR_P (expr))
	    TREE_VALUE (arg)
	      = fold_non_dependent_expr (expr, tf_warning_or_error,
					 manifestly_const_eval);
	}
    }
}

/* Return true if TYPE is an OpenMP mappable type.
   If NOTES is non-zero, emit a note message for each problem.  */
static bool
cp_omp_mappable_type_1 (tree type, bool notes)
{
  bool result = true;

  /* Mappable type has to be complete.  */
  if (type == error_mark_node || !COMPLETE_TYPE_P (type))
    {
      if (notes && type != error_mark_node)
	{
	  tree decl = TYPE_MAIN_DECL (type);
	  inform ((decl ? DECL_SOURCE_LOCATION (decl) : input_location),
		  "incomplete type %qT is not mappable", type);
	}
      result = false;
    }
  /* Arrays have mappable type if the elements have mappable type.  */
  while (TREE_CODE (type) == ARRAY_TYPE)
    type = TREE_TYPE (type);
  /* All data members must be non-static.  */
  if (CLASS_TYPE_P (type))
    {
      tree field;
      for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
	if (VAR_P (field))
	  {
	    if (notes)
	      inform (DECL_SOURCE_LOCATION (field),
		      "static field %qD is not mappable", field);
	    result = false;
	  }
	/* All fields must have mappable types.  */
	else if (TREE_CODE (field) == FIELD_DECL
		 && !cp_omp_mappable_type_1 (TREE_TYPE (field), notes))
	  result = false;
    }
  return result;
}

/* Return true if TYPE is an OpenMP mappable type.  */
bool
cp_omp_mappable_type (tree type)
{
  return cp_omp_mappable_type_1 (type, false);
}

/* Return true if TYPE is an OpenMP mappable type.
   Emit an error messages if not.  */
bool
cp_omp_emit_unmappable_type_notes (tree type)
{
  return cp_omp_mappable_type_1 (type, true);
}

/* Return the last pushed declaration for the symbol DECL or NULL
   when no such declaration exists.  */

static tree
find_last_decl (tree decl)
{
  tree last_decl = NULL_TREE;

  if (tree name = DECL_P (decl) ? DECL_NAME (decl) : NULL_TREE)
    {
      /* Look up the declaration in its scope.  */
      tree pushed_scope = NULL_TREE;
      if (tree ctype = DECL_CONTEXT (decl))
	pushed_scope = push_scope (ctype);

      last_decl = lookup_name (name);

      if (pushed_scope)
	pop_scope (pushed_scope);

      /* The declaration may be a member conversion operator
	 or a bunch of overfloads (handle the latter below).  */
      if (last_decl && BASELINK_P (last_decl))
	last_decl = BASELINK_FUNCTIONS (last_decl);
    }

  if (!last_decl)
    return NULL_TREE;

  if (DECL_P (last_decl) || TREE_CODE (last_decl) == OVERLOAD)
    {
      /* A set of overloads of the same function.  */
      for (lkp_iterator iter (last_decl); iter; ++iter)
	{
	  if (TREE_CODE (*iter) == OVERLOAD)
	    continue;

	  tree d = *iter;

	  /* We can't compare versions in the middle of processing the
	     attribute that has the version.  */
	  if (TREE_CODE (d) == FUNCTION_DECL
	      && DECL_FUNCTION_VERSIONED (d))
	    return NULL_TREE;

	  if (decls_match (decl, d, /*record_decls=*/false))
	    return d;
	}
      return NULL_TREE;
    }

  return NULL_TREE;
}

/* Like decl_attributes, but handle C++ complexity.  */

void
cplus_decl_attributes (tree *decl, tree attributes, int flags)
{
  if (*decl == NULL_TREE || *decl == void_type_node
      || *decl == error_mark_node || attributes == error_mark_node)
    return;

  /* Add implicit "omp declare target" attribute if requested.  */
  if (vec_safe_length (scope_chain->omp_declare_target_attribute)
      && ((VAR_P (*decl)
	   && (TREE_STATIC (*decl) || DECL_EXTERNAL (*decl)))
	  || TREE_CODE (*decl) == FUNCTION_DECL))
    {
      if (VAR_P (*decl)
	  && DECL_CLASS_SCOPE_P (*decl))
	error ("%q+D static data member inside of declare target directive",
	       *decl);
      else if (VAR_P (*decl)
	       && (processing_template_decl
		   || !cp_omp_mappable_type (TREE_TYPE (*decl))))
	attributes = tree_cons (get_identifier ("omp declare target implicit"),
				NULL_TREE, attributes);
      else
	{
	  attributes = tree_cons (get_identifier ("omp declare target"),
				  NULL_TREE, attributes);
	  attributes = tree_cons (get_identifier ("omp declare target block"),
				  NULL_TREE, attributes);
	}
    }

  tree late_attrs = NULL_TREE;
  if (processing_template_decl)
    {
      if (check_for_bare_parameter_packs (attributes))
	return;
      late_attrs = splice_template_attributes (&attributes, *decl);
    }

  cp_check_const_attributes (attributes);

  if (flag_openmp || flag_openmp_simd)
    {
      bool diagnosed = false;
      for (tree *pa = &attributes; *pa; )
	{
	  if (get_attribute_namespace (*pa) == omp_identifier)
	    {
	      tree name = get_attribute_name (*pa);
	      if (is_attribute_p ("directive", name)
		  || is_attribute_p ("sequence", name))
		{
		  if (!diagnosed)
		    {
		      error ("%<omp::%E%> not allowed to be specified in this "
			     "context", name);
		      diagnosed = true;
		    }
		  *pa = TREE_CHAIN (*pa);
		  continue;
		}
	    }
	  pa = &TREE_CHAIN (*pa);
	}
    }

  if (TREE_CODE (*decl) == TEMPLATE_DECL)
    decl = &DECL_TEMPLATE_RESULT (*decl);

  if (TREE_TYPE (*decl) && TYPE_PTRMEMFUNC_P (TREE_TYPE (*decl)))
    {
      attributes
	= decl_attributes (decl, attributes, flags | ATTR_FLAG_FUNCTION_NEXT);
      decl_attributes (&TYPE_PTRMEMFUNC_FN_TYPE_RAW (TREE_TYPE (*decl)),
		       attributes, flags);
    }
  else
    {
      tree last_decl = find_last_decl (*decl);
      decl_attributes (decl, attributes, flags, last_decl);
    }

  if (late_attrs)
    save_template_attributes (late_attrs, decl, flags);

  /* Propagate deprecation out to the template.  */
  if (TREE_DEPRECATED (*decl))
    if (tree ti = get_template_info (*decl))
      {
	tree tmpl = TI_TEMPLATE (ti);
	tree pattern = (TYPE_P (*decl) ? TREE_TYPE (tmpl)
			: DECL_TEMPLATE_RESULT (tmpl));
	if (*decl == pattern)
	  TREE_DEPRECATED (tmpl) = true;
      }

  /* Likewise, propagate unavailability out to the template.  */
  if (TREE_UNAVAILABLE (*decl))
    if (tree ti = get_template_info (*decl))
      {
	tree tmpl = TI_TEMPLATE (ti);
	tree pattern = (TYPE_P (*decl) ? TREE_TYPE (tmpl)
			: DECL_TEMPLATE_RESULT (tmpl));
	if (*decl == pattern)
	  TREE_UNAVAILABLE (tmpl) = true;
      }
}

/* Walks through the namespace- or function-scope anonymous union
   OBJECT, with the indicated TYPE, building appropriate VAR_DECLs.
   Returns one of the fields for use in the mangled name.  */

static tree
build_anon_union_vars (tree type, tree object)
{
  tree main_decl = NULL_TREE;
  tree field;

  /* Rather than write the code to handle the non-union case,
     just give an error.  */
  if (TREE_CODE (type) != UNION_TYPE)
    {
      error_at (DECL_SOURCE_LOCATION (TYPE_MAIN_DECL (type)),
		"anonymous struct not inside named type");
      return error_mark_node;
    }

  for (field = TYPE_FIELDS (type);
       field != NULL_TREE;
       field = DECL_CHAIN (field))
    {
      tree decl;
      tree ref;

      if (DECL_ARTIFICIAL (field))
	continue;
      if (TREE_CODE (field) != FIELD_DECL)
	{
	  permerror (DECL_SOURCE_LOCATION (field),
		     "%q#D invalid; an anonymous union can only "
		     "have non-static data members", field);
	  continue;
	}

      if (TREE_PRIVATE (field))
	permerror (DECL_SOURCE_LOCATION (field),
		   "private member %q#D in anonymous union", field);
      else if (TREE_PROTECTED (field))
	permerror (DECL_SOURCE_LOCATION (field),
		   "protected member %q#D in anonymous union", field);

      if (processing_template_decl)
	ref = build_min_nt_loc (UNKNOWN_LOCATION, COMPONENT_REF, object,
				DECL_NAME (field), NULL_TREE);
      else
	ref = build_class_member_access_expr (object, field, NULL_TREE,
					      false, tf_warning_or_error);

      if (DECL_NAME (field))
	{
	  tree base;

	  decl = build_decl (input_location,
			     VAR_DECL, DECL_NAME (field), TREE_TYPE (field));
	  DECL_ANON_UNION_VAR_P (decl) = 1;
	  DECL_ARTIFICIAL (decl) = 1;

	  base = get_base_address (object);
	  TREE_PUBLIC (decl) = TREE_PUBLIC (base);
	  TREE_STATIC (decl) = TREE_STATIC (base);
	  DECL_EXTERNAL (decl) = DECL_EXTERNAL (base);

	  SET_DECL_VALUE_EXPR (decl, ref);
	  DECL_HAS_VALUE_EXPR_P (decl) = 1;

	  decl = pushdecl (decl);
	}
      else if (ANON_AGGR_TYPE_P (TREE_TYPE (field)))
	decl = build_anon_union_vars (TREE_TYPE (field), ref);
      else
	decl = 0;

      if (main_decl == NULL_TREE)
	main_decl = decl;
    }

  return main_decl;
}

/* Finish off the processing of a UNION_TYPE structure.  If the union is an
   anonymous union, then all members must be laid out together.  PUBLIC_P
   is nonzero if this union is not declared static.  */

void
finish_anon_union (tree anon_union_decl)
{
  tree type;
  tree main_decl;
  bool public_p;

  if (anon_union_decl == error_mark_node)
    return;

  type = TREE_TYPE (anon_union_decl);
  public_p = TREE_PUBLIC (anon_union_decl);

  /* The VAR_DECL's context is the same as the TYPE's context.  */
  DECL_CONTEXT (anon_union_decl) = DECL_CONTEXT (TYPE_NAME (type));

  if (TYPE_FIELDS (type) == NULL_TREE)
    return;

  if (public_p)
    {
      error ("namespace-scope anonymous aggregates must be static");
      return;
    }

  main_decl = build_anon_union_vars (type, anon_union_decl);
  if (main_decl == error_mark_node)
    return;
  if (main_decl == NULL_TREE)
    {
      pedwarn (input_location, 0, "anonymous union with no members");
      return;
    }

  if (!processing_template_decl)
    {
      /* Use main_decl to set the mangled name.  */
      DECL_NAME (anon_union_decl) = DECL_NAME (main_decl);
      maybe_commonize_var (anon_union_decl);
      if (TREE_STATIC (anon_union_decl) || DECL_EXTERNAL (anon_union_decl))
	{
	  if (DECL_DISCRIMINATOR_P (anon_union_decl))
	    determine_local_discriminator (anon_union_decl);
	  mangle_decl (anon_union_decl);
	}
      DECL_NAME (anon_union_decl) = NULL_TREE;
    }

  pushdecl (anon_union_decl);
  cp_finish_decl (anon_union_decl, NULL_TREE, false, NULL_TREE, 0);
}

/* Auxiliary functions to make type signatures for
   `operator new' and `operator delete' correspond to
   what compiler will be expecting.  */

tree
coerce_new_type (tree type, location_t loc)
{
  int e = 0;
  tree args = TYPE_ARG_TYPES (type);

  gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);

  if (!same_type_p (TREE_TYPE (type), ptr_type_node))
    {
      e = 1;
      error_at (loc, "%<operator new%> must return type %qT",
		ptr_type_node);
    }

  if (args && args != void_list_node)
    {
      if (TREE_PURPOSE (args))
	{
	  /* [basic.stc.dynamic.allocation]
	     
	     The first parameter shall not have an associated default
	     argument.  */
	  error_at (loc, "the first parameter of %<operator new%> cannot "
		    "have a default argument");
	  /* Throw away the default argument.  */
	  TREE_PURPOSE (args) = NULL_TREE;
	}

      if (!same_type_p (TREE_VALUE (args), size_type_node))
	{
	  e = 2;
	  args = TREE_CHAIN (args);
	}
    }
  else
    e = 2;

  if (e == 2)
    permerror (loc, "%<operator new%> takes type %<size_t%> (%qT) "
	       "as first parameter", size_type_node);

  switch (e)
  {
    case 2:
      args = tree_cons (NULL_TREE, size_type_node, args);
      /* Fall through.  */
    case 1:
      type = (cxx_copy_lang_qualifiers
	      (build_function_type (ptr_type_node, args),
	       type));
      /* Fall through.  */
    default:;
  }
  return type;
}

void
coerce_delete_type (tree decl, location_t loc)
{
  int e = 0;
  tree type = TREE_TYPE (decl);
  tree args = TYPE_ARG_TYPES (type);

  gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);

  if (!same_type_p (TREE_TYPE (type), void_type_node))
    {
      e = 1;
      error_at (loc, "%<operator delete%> must return type %qT",
		void_type_node);
    }

  tree ptrtype = ptr_type_node;
  if (destroying_delete_p (decl))
    {
      if (DECL_CLASS_SCOPE_P (decl))
	/* If the function is a destroying operator delete declared in class
	   type C, the type of its first parameter shall be C*.  */
	ptrtype = build_pointer_type (DECL_CONTEXT (decl));
      else
	/* A destroying operator delete shall be a class member function named
	   operator delete.  */
	error_at (loc,
		  "destroying %<operator delete%> must be a member function");
      const ovl_op_info_t *op = IDENTIFIER_OVL_OP_INFO (DECL_NAME (decl));
      if (op->flags & OVL_OP_FLAG_VEC)
	error_at (loc, "%<operator delete[]%> cannot be a destroying delete");
      if (!usual_deallocation_fn_p (decl))
	error_at (loc, "destroying %<operator delete%> must be a usual "
		  "deallocation function");
    }

  if (!args || args == void_list_node
      || !same_type_p (TREE_VALUE (args), ptrtype))
    {
      e = 2;
      if (args && args != void_list_node)
	args = TREE_CHAIN (args);
      error_at (loc, "%<operator delete%> takes type %qT as first parameter",
		ptrtype);
    }
  switch (e)
  {
    case 2:
      args = tree_cons (NULL_TREE, ptrtype, args);
      /* Fall through.  */
    case 1:
      type = (cxx_copy_lang_qualifiers
	      (build_function_type (void_type_node, args),
	       type));
      /* Fall through.  */
    default:;
  }

  TREE_TYPE (decl) = type;
}

/* DECL is a VAR_DECL for a vtable: walk through the entries in the vtable
   and mark them as needed.  */

static void
mark_vtable_entries (tree decl, vec<tree> &consteval_vtables)
{
  /* It's OK for the vtable to refer to deprecated virtual functions.  */
  warning_sentinel w(warn_deprecated_decl);

  bool consteval_seen = false;

  for (auto &e: CONSTRUCTOR_ELTS (DECL_INITIAL (decl)))
    {
      tree fnaddr = e.value;

      STRIP_NOPS (fnaddr);

      if (TREE_CODE (fnaddr) != ADDR_EXPR
	  && TREE_CODE (fnaddr) != FDESC_EXPR)
	/* This entry is an offset: a virtual base class offset, a
	   virtual call offset, an RTTI offset, etc.  */
	continue;

      tree fn = TREE_OPERAND (fnaddr, 0);
      if (TREE_CODE (fn) == FUNCTION_DECL && DECL_IMMEDIATE_FUNCTION_P (fn))
	{
	  if (!consteval_seen)
	    {
	      consteval_seen = true;
	      consteval_vtables.safe_push (decl);
	    }
	  continue;
	}
      TREE_ADDRESSABLE (fn) = 1;
      /* When we don't have vcall offsets, we output thunks whenever
	 we output the vtables that contain them.  With vcall offsets,
	 we know all the thunks we'll need when we emit a virtual
	 function, so we emit the thunks there instead.  */
      if (DECL_THUNK_P (fn))
	use_thunk (fn, /*emit_p=*/0);
      /* Set the location, as marking the function could cause
         instantiation.  We do not need to preserve the incoming
         location, as we're called from c_parse_final_cleanups, which
         takes care of that.  */
      input_location = DECL_SOURCE_LOCATION (fn);
      mark_used (fn);
    }
}

/* Replace any consteval functions in vtables with null pointers.  */

static void
clear_consteval_vfns (vec<tree> &consteval_vtables)
{
  for (tree vtable : consteval_vtables)
    for (constructor_elt &elt : CONSTRUCTOR_ELTS (DECL_INITIAL (vtable)))
      {
	tree fn = cp_get_fndecl_from_callee (elt.value, /*fold*/false);
	if (fn && DECL_IMMEDIATE_FUNCTION_P (fn))
	  elt.value = build_zero_cst (vtable_entry_type);
      }
}

/* Adjust the TLS model on variable DECL if need be, typically after
   the linkage of DECL has been modified.  */

static void
adjust_var_decl_tls_model (tree decl)
{
  if (CP_DECL_THREAD_LOCAL_P (decl)
      && !lookup_attribute ("tls_model", DECL_ATTRIBUTES (decl)))
    set_decl_tls_model (decl, decl_default_tls_model (decl));
}

/* Set DECL up to have the closest approximation of "initialized common"
   linkage available.  */

void
comdat_linkage (tree decl)
{
  if (flag_weak)
    make_decl_one_only (decl, cxx_comdat_group (decl));
  else if (TREE_CODE (decl) == FUNCTION_DECL
	   || (VAR_P (decl) && DECL_ARTIFICIAL (decl)))
    /* We can just emit function and compiler-generated variables
       statically; having multiple copies is (for the most part) only
       a waste of space.

       There are two correctness issues, however: the address of a
       template instantiation with external linkage should be the
       same, independent of what translation unit asks for the
       address, and this will not hold when we emit multiple copies of
       the function.  However, there's little else we can do.

       Also, by default, the typeinfo implementation assumes that
       there will be only one copy of the string used as the name for
       each type.  Therefore, if weak symbols are unavailable, the
       run-time library should perform a more conservative check; it
       should perform a string comparison, rather than an address
       comparison.  */
    TREE_PUBLIC (decl) = 0;
  else
    {
      /* Static data member template instantiations, however, cannot
	 have multiple copies.  */
      if (DECL_INITIAL (decl) == 0
	  || DECL_INITIAL (decl) == error_mark_node)
	DECL_COMMON (decl) = 1;
      else if (EMPTY_CONSTRUCTOR_P (DECL_INITIAL (decl)))
	{
	  DECL_COMMON (decl) = 1;
	  DECL_INITIAL (decl) = error_mark_node;
	}
      else if (!DECL_EXPLICIT_INSTANTIATION (decl))
	{
	  /* We can't do anything useful; leave vars for explicit
	     instantiation.  */
	  DECL_EXTERNAL (decl) = 1;
	  DECL_NOT_REALLY_EXTERN (decl) = 0;
	}
    }

  if (TREE_PUBLIC (decl))
    DECL_COMDAT (decl) = 1;

  if (VAR_P (decl))
    adjust_var_decl_tls_model (decl);
}

/* For win32 we also want to put explicit instantiations in
   linkonce sections, so that they will be merged with implicit
   instantiations; otherwise we get duplicate symbol errors.
   For Darwin we do not want explicit instantiations to be
   linkonce.  */

void
maybe_make_one_only (tree decl)
{
  /* We used to say that this was not necessary on targets that support weak
     symbols, because the implicit instantiations will defer to the explicit
     one.  However, that's not actually the case in SVR4; a strong definition
     after a weak one is an error.  Also, not making explicit
     instantiations one_only means that we can end up with two copies of
     some template instantiations.  */
  if (! flag_weak)
    return;

  /* We can't set DECL_COMDAT on functions, or cp_finish_file will think
     we can get away with not emitting them if they aren't used.  We need
     to for variables so that cp_finish_decl will update their linkage,
     because their DECL_INITIAL may not have been set properly yet.  */

  if (!TARGET_WEAK_NOT_IN_ARCHIVE_TOC
      || (! DECL_EXPLICIT_INSTANTIATION (decl)
	  && ! DECL_TEMPLATE_SPECIALIZATION (decl)))
    {
      make_decl_one_only (decl, cxx_comdat_group (decl));

      if (VAR_P (decl))
	{
	  varpool_node *node = varpool_node::get_create (decl);
	  DECL_COMDAT (decl) = 1;
	  /* Mark it needed so we don't forget to emit it.  */
          node->forced_by_abi = true;
	  TREE_USED (decl) = 1;

	  adjust_var_decl_tls_model (decl);
	}
    }
}

/* Returns true iff DECL, a FUNCTION_DECL or VAR_DECL, has vague linkage.
   This predicate will give the right answer during parsing of the
   function, which other tests may not.  */

bool
vague_linkage_p (tree decl)
{
  if (!TREE_PUBLIC (decl))
    {
      /* maybe_thunk_body clears TREE_PUBLIC and DECL_ABSTRACT_P on the
	 maybe-in-charge 'tor variants; in that case we need to check one of
	 the "clones" for the real linkage.  But only in that case; before
	 maybe_clone_body we haven't yet copied the linkage to the clones.  */
      if (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl)
	  && !DECL_ABSTRACT_P (decl)
	  && DECL_CHAIN (decl)
	  && DECL_CLONED_FUNCTION_P (DECL_CHAIN (decl)))
	return vague_linkage_p (DECL_CHAIN (decl));

      gcc_checking_assert (!DECL_COMDAT (decl));
      return false;
    }
  /* Unfortunately, import_export_decl has not always been called
     before the function is processed, so we cannot simply check
     DECL_COMDAT.  */
  if (DECL_COMDAT (decl)
      || (TREE_CODE (decl) == FUNCTION_DECL
	  && DECL_DECLARED_INLINE_P (decl))
      || (DECL_LANG_SPECIFIC (decl)
	  && DECL_TEMPLATE_INSTANTIATION (decl))
      || (VAR_P (decl) && DECL_INLINE_VAR_P (decl)))
    return true;
  else if (DECL_FUNCTION_SCOPE_P (decl))
    /* A local static in an inline effectively has vague linkage.  */
    return (TREE_STATIC (decl)
	    && vague_linkage_p (DECL_CONTEXT (decl)));
  else
    return false;
}

/* Determine whether or not we want to specifically import or export CTYPE,
   using various heuristics.  */

static void
import_export_class (tree ctype)
{
  /* -1 for imported, 1 for exported.  */
  int import_export = 0;

  /* It only makes sense to call this function at EOF.  The reason is
     that this function looks at whether or not the first non-inline
     non-abstract virtual member function has been defined in this
     translation unit.  But, we can't possibly know that until we've
     seen the entire translation unit.  */
  gcc_assert (at_eof);

  if (CLASSTYPE_INTERFACE_KNOWN (ctype))
    return;

  /* If MULTIPLE_SYMBOL_SPACES is set and we saw a #pragma interface,
     we will have CLASSTYPE_INTERFACE_ONLY set but not
     CLASSTYPE_INTERFACE_KNOWN.  In that case, we don't want to use this
     heuristic because someone will supply a #pragma implementation
     elsewhere, and deducing it here would produce a conflict.  */
  if (CLASSTYPE_INTERFACE_ONLY (ctype))
    return;

  if (lookup_attribute ("dllimport", TYPE_ATTRIBUTES (ctype)))
    import_export = -1;
  else if (lookup_attribute ("dllexport", TYPE_ATTRIBUTES (ctype)))
    import_export = 1;
  else if (CLASSTYPE_IMPLICIT_INSTANTIATION (ctype)
	   && !flag_implicit_templates)
    /* For a template class, without -fimplicit-templates, check the
       repository.  If the virtual table is assigned to this
       translation unit, then export the class; otherwise, import
       it.  */
      import_export = -1;
  else if (TYPE_POLYMORPHIC_P (ctype))
    {
      /* The ABI specifies that the virtual table and associated
	 information are emitted with the key method, if any.  */
      tree method = CLASSTYPE_KEY_METHOD (ctype);
      /* If weak symbol support is not available, then we must be
	 careful not to emit the vtable when the key function is
	 inline.  An inline function can be defined in multiple
	 translation units.  If we were to emit the vtable in each
	 translation unit containing a definition, we would get
	 multiple definition errors at link-time.  */
      if (method && (flag_weak || ! DECL_DECLARED_INLINE_P (method)))
	import_export = (DECL_REALLY_EXTERN (method) ? -1 : 1);
    }

  /* When MULTIPLE_SYMBOL_SPACES is set, we cannot count on seeing
     a definition anywhere else.  */
  if (MULTIPLE_SYMBOL_SPACES && import_export == -1)
    import_export = 0;

  /* Allow back ends the chance to overrule the decision.  */
  if (targetm.cxx.import_export_class)
    import_export = targetm.cxx.import_export_class (ctype, import_export);

  if (import_export)
    {
      SET_CLASSTYPE_INTERFACE_KNOWN (ctype);
      CLASSTYPE_INTERFACE_ONLY (ctype) = (import_export < 0);
    }
}

/* Return true if VAR has already been provided to the back end; in that
   case VAR should not be modified further by the front end.  */
static bool
var_finalized_p (tree var)
{
  return varpool_node::get_create (var)->definition;
}

/* DECL is a VAR_DECL or FUNCTION_DECL which, for whatever reason,
   must be emitted in this translation unit.  Mark it as such.  */

void
mark_needed (tree decl)
{
  TREE_USED (decl) = 1;
  if (TREE_CODE (decl) == FUNCTION_DECL)
    {
      /* Extern inline functions don't become needed when referenced.
	 If we know a method will be emitted in other TU and no new
	 functions can be marked reachable, just use the external
	 definition.  */
      struct cgraph_node *node = cgraph_node::get_create (decl);
      node->forced_by_abi = true;

      /* #pragma interface can call mark_needed for
          maybe-in-charge 'tors; mark the clones as well.  */
      tree clone;
      FOR_EACH_CLONE (clone, decl)
	mark_needed (clone);
    }
  else if (VAR_P (decl))
    {
      varpool_node *node = varpool_node::get_create (decl);
      /* C++ frontend use mark_decl_references to force COMDAT variables
         to be output that might appear dead otherwise.  */
      node->forced_by_abi = true;
    }
}

/* DECL is either a FUNCTION_DECL or a VAR_DECL.  This function
   returns true if a definition of this entity should be provided in
   this object file.  Callers use this function to determine whether
   or not to let the back end know that a definition of DECL is
   available in this translation unit.  */

bool
decl_needed_p (tree decl)
{
  gcc_assert (VAR_OR_FUNCTION_DECL_P (decl));
  /* This function should only be called at the end of the translation
     unit.  We cannot be sure of whether or not something will be
     COMDAT until that point.  */
  gcc_assert (at_eof);

  /* All entities with external linkage that are not COMDAT/EXTERN should be
     emitted; they may be referred to from other object files.  */
  if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_REALLY_EXTERN (decl))
    return true;

  /* Functions marked "dllexport" must be emitted so that they are
     visible to other DLLs.  */
  if (flag_keep_inline_dllexport
      && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
    return true;

  /* When not optimizing, do not bother to produce definitions for extern
     symbols.  */
  if (DECL_REALLY_EXTERN (decl)
      && ((TREE_CODE (decl) != FUNCTION_DECL
	   && !optimize)
	  || (TREE_CODE (decl) == FUNCTION_DECL
	      && !opt_for_fn (decl, optimize)))
      && !lookup_attribute ("always_inline", decl))
    return false;

  /* If this entity was used, let the back end see it; it will decide
     whether or not to emit it into the object file.  */
  if (TREE_USED (decl))
    return true;

  /* Virtual functions might be needed for devirtualization.  */
  if (flag_devirtualize
      && TREE_CODE (decl) == FUNCTION_DECL
      && DECL_VIRTUAL_P (decl))
    return true;

  /* Otherwise, DECL does not need to be emitted -- yet.  A subsequent
     reference to DECL might cause it to be emitted later.  */
  return false;
}

/* If necessary, write out the vtables for the dynamic class CTYPE.
   Returns true if any vtables were emitted.  */

static bool
maybe_emit_vtables (tree ctype, vec<tree> &consteval_vtables)
{
  tree vtbl;
  tree primary_vtbl;
  int needed = 0;
  varpool_node *current = NULL, *last = NULL;

  /* If the vtables for this class have already been emitted there is
     nothing more to do.  */
  primary_vtbl = CLASSTYPE_VTABLES (ctype);
  if (var_finalized_p (primary_vtbl))
    return false;
  /* Ignore dummy vtables made by get_vtable_decl.  */
  if (TREE_TYPE (primary_vtbl) == void_type_node)
    return false;

  /* On some targets, we cannot determine the key method until the end
     of the translation unit -- which is when this function is
     called.  */
  if (!targetm.cxx.key_method_may_be_inline ())
    determine_key_method (ctype);

  /* See if any of the vtables are needed.  */
  for (vtbl = CLASSTYPE_VTABLES (ctype); vtbl; vtbl = DECL_CHAIN (vtbl))
    {
      import_export_decl (vtbl);
      if (DECL_NOT_REALLY_EXTERN (vtbl) && decl_needed_p (vtbl))
	needed = 1;
    }
  if (!needed)
    {
      /* If the references to this class' vtables are optimized away,
	 still emit the appropriate debugging information.  See
	 dfs_debug_mark.  */
      if (DECL_COMDAT (primary_vtbl)
	  && CLASSTYPE_DEBUG_REQUESTED (ctype))
	note_debug_info_needed (ctype);
      return false;
    }

  /* The ABI requires that we emit all of the vtables if we emit any
     of them.  */
  for (vtbl = CLASSTYPE_VTABLES (ctype); vtbl; vtbl = DECL_CHAIN (vtbl))
    {
      /* Mark entities references from the virtual table as used.  */
      mark_vtable_entries (vtbl, consteval_vtables);

      if (TREE_TYPE (DECL_INITIAL (vtbl)) == 0)
	{
	  vec<tree, va_gc> *cleanups = NULL;
	  tree expr = store_init_value (vtbl, DECL_INITIAL (vtbl), &cleanups,
					LOOKUP_NORMAL);

	  /* It had better be all done at compile-time.  */
	  gcc_assert (!expr && !cleanups);
	}

      /* Write it out.  */
      DECL_EXTERNAL (vtbl) = 0;
      rest_of_decl_compilation (vtbl, 1, 1);

      /* Because we're only doing syntax-checking, we'll never end up
	 actually marking the variable as written.  */
      if (flag_syntax_only)
	TREE_ASM_WRITTEN (vtbl) = 1;
      else if (DECL_ONE_ONLY (vtbl))
	{
	  current = varpool_node::get_create (vtbl);
	  if (last)
	    current->add_to_same_comdat_group (last);
	  last = current;
	}
    }

  /* For abstract classes, the destructor has been removed from the
     vtable (in class.cc's build_vtbl_initializer).  For a compiler-
     generated destructor, it hence might not have been generated in
     this translation unit - and with '#pragma interface' it might
     never get generated.  */
  if (CLASSTYPE_PURE_VIRTUALS (ctype)
      && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype)
      && !CLASSTYPE_LAZY_DESTRUCTOR (ctype)
      && DECL_DEFAULTED_IN_CLASS_P (CLASSTYPE_DESTRUCTOR (ctype)))
    note_vague_linkage_fn (CLASSTYPE_DESTRUCTOR (ctype));

  /* Since we're writing out the vtable here, also write the debug
     info.  */
  note_debug_info_needed (ctype);

  return true;
}

/* A special return value from type_visibility meaning internal
   linkage.  */

enum { VISIBILITY_ANON = VISIBILITY_INTERNAL+1 };

static int expr_visibility (tree);
static int type_visibility (tree);

/* walk_tree helper function for type_visibility.  */

static tree
min_vis_r (tree *tp, int *walk_subtrees, void *data)
{
  int *vis_p = (int *)data;
  int this_vis = VISIBILITY_DEFAULT;
  if (! TYPE_P (*tp))
    *walk_subtrees = 0;
  else if (OVERLOAD_TYPE_P (*tp)
	   && !TREE_PUBLIC (TYPE_MAIN_DECL (*tp)))
    {
      this_vis = VISIBILITY_ANON;
      *walk_subtrees = 0;
    }
  else if (CLASS_TYPE_P (*tp))
    {
      this_vis = CLASSTYPE_VISIBILITY (*tp);
      *walk_subtrees = 0;
    }
  else if (TREE_CODE (*tp) == ARRAY_TYPE
	   && uses_template_parms (TYPE_DOMAIN (*tp)))
    this_vis = expr_visibility (TYPE_MAX_VALUE (TYPE_DOMAIN (*tp)));

  if (this_vis > *vis_p)
    *vis_p = this_vis;

  /* Tell cp_walk_subtrees to look through typedefs.  */
  if (*walk_subtrees == 1)
    *walk_subtrees = 2;

  return NULL;
}

/* walk_tree helper function for expr_visibility.  */

static tree
min_vis_expr_r (tree *tp, int */*walk_subtrees*/, void *data)
{
  int *vis_p = (int *)data;
  int tpvis = VISIBILITY_DEFAULT;

  switch (TREE_CODE (*tp))
    {
    case CAST_EXPR:
    case IMPLICIT_CONV_EXPR:
    case STATIC_CAST_EXPR:
    case REINTERPRET_CAST_EXPR:
    case CONST_CAST_EXPR:
    case DYNAMIC_CAST_EXPR:
    case NEW_EXPR:
    case CONSTRUCTOR:
    case LAMBDA_EXPR:
      tpvis = type_visibility (TREE_TYPE (*tp));
      break;

    case VAR_DECL:
    case FUNCTION_DECL:
      if (! TREE_PUBLIC (*tp))
	tpvis = VISIBILITY_ANON;
      else
	tpvis = DECL_VISIBILITY (*tp);
      break;

    default:
      break;
    }

  if (tpvis > *vis_p)
    *vis_p = tpvis;

  return NULL_TREE;
}

/* Returns the visibility of TYPE, which is the minimum visibility of its
   component types.  */

static int
type_visibility (tree type)
{
  int vis = VISIBILITY_DEFAULT;
  cp_walk_tree_without_duplicates (&type, min_vis_r, &vis);
  return vis;
}

/* Returns the visibility of an expression EXPR that appears in the signature
   of a function template, which is the minimum visibility of names that appear
   in its mangling.  */

static int
expr_visibility (tree expr)
{
  int vis = VISIBILITY_DEFAULT;
  cp_walk_tree_without_duplicates (&expr, min_vis_expr_r, &vis);
  return vis;
}

/* Limit the visibility of DECL to VISIBILITY, if not explicitly
   specified (or if VISIBILITY is static).  If TMPL is true, this
   constraint is for a template argument, and takes precedence
   over explicitly-specified visibility on the template.  */

static void
constrain_visibility (tree decl, int visibility, bool tmpl)
{
  if (visibility == VISIBILITY_ANON)
    {
      /* extern "C" declarations aren't affected by the anonymous
	 namespace.  */
      if (!DECL_EXTERN_C_P (decl))
	{
	  TREE_PUBLIC (decl) = 0;
	  DECL_WEAK (decl) = 0;
	  DECL_COMMON (decl) = 0;
	  DECL_COMDAT (decl) = false;
	  if (VAR_OR_FUNCTION_DECL_P (decl))
	    {
	      struct symtab_node *snode = symtab_node::get (decl);

	      if (snode)
	        snode->set_comdat_group (NULL);
	    }
	  DECL_INTERFACE_KNOWN (decl) = 1;
	  if (DECL_LANG_SPECIFIC (decl))
	    DECL_NOT_REALLY_EXTERN (decl) = 1;
	}
    }
  else if (visibility > DECL_VISIBILITY (decl)
	   && (tmpl || !DECL_VISIBILITY_SPECIFIED (decl)))
    {
      DECL_VISIBILITY (decl) = (enum symbol_visibility) visibility;
      /* This visibility was not specified.  */
      DECL_VISIBILITY_SPECIFIED (decl) = false;
    }
}

/* Constrain the visibility of DECL based on the visibility of its template
   arguments.  */

static void
constrain_visibility_for_template (tree decl, tree targs)
{
  /* If this is a template instantiation, check the innermost
     template args for visibility constraints.  The outer template
     args are covered by the class check.  */
  tree args = INNERMOST_TEMPLATE_ARGS (targs);
  int i;
  for (i = TREE_VEC_LENGTH (args); i > 0; --i)
    {
      int vis = 0;

      tree arg = TREE_VEC_ELT (args, i-1);
      if (TYPE_P (arg))
	vis = type_visibility (arg);
      else
	vis = expr_visibility (arg);
      if (vis)
	constrain_visibility (decl, vis, true);
    }
}

/* Like c_determine_visibility, but with additional C++-specific
   behavior.

   Function-scope entities can rely on the function's visibility because
   it is set in start_preparsed_function.

   Class-scope entities cannot rely on the class's visibility until the end
   of the enclosing class definition.

   Note that because namespaces have multiple independent definitions,
   namespace visibility is handled elsewhere using the #pragma visibility
   machinery rather than by decorating the namespace declaration.

   The goal is for constraints from the type to give a diagnostic, and
   other constraints to be applied silently.  */

void
determine_visibility (tree decl)
{
  /* Remember that all decls get VISIBILITY_DEFAULT when built.  */

  /* Only relevant for names with external linkage.  */
  if (!TREE_PUBLIC (decl))
    return;

  /* Cloned constructors and destructors get the same visibility as
     the underlying function.  That should be set up in
     maybe_clone_body.  */
  gcc_assert (!DECL_CLONED_FUNCTION_P (decl));

  bool orig_visibility_specified = DECL_VISIBILITY_SPECIFIED (decl);
  enum symbol_visibility orig_visibility = DECL_VISIBILITY (decl);

  /* The decl may be a template instantiation, which could influence
     visibilty.  */
  tree template_decl = NULL_TREE;
  if (TREE_CODE (decl) == TYPE_DECL)
    {
      if (CLASS_TYPE_P (TREE_TYPE (decl)))
	{
	  if (CLASSTYPE_USE_TEMPLATE (TREE_TYPE (decl)))
	    template_decl = decl;
	}
      else if (TYPE_TEMPLATE_INFO (TREE_TYPE (decl)))
	template_decl = decl;
    }
  else if (DECL_LANG_SPECIFIC (decl) && DECL_USE_TEMPLATE (decl))
    template_decl = decl;

  if (TREE_CODE (decl) == TYPE_DECL
      && LAMBDA_TYPE_P (TREE_TYPE (decl))
      && CLASSTYPE_LAMBDA_EXPR (TREE_TYPE (decl)) != error_mark_node)
    if (tree extra = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl)))
      {
	/* The lambda's visibility is limited by that of its extra
	   scope.  */
	int vis = 0;
	if (TYPE_P (extra))
	  vis = type_visibility (extra);
	else
	  vis = expr_visibility (extra);
	constrain_visibility (decl, vis, false);
      }

  /* If DECL is a member of a class, visibility specifiers on the
     class can influence the visibility of the DECL.  */
  tree class_type = NULL_TREE;
  if (DECL_CLASS_SCOPE_P (decl))
    class_type = DECL_CONTEXT (decl);
  else
    {
      /* Not a class member.  */

      /* Virtual tables have DECL_CONTEXT set to their associated class,
	 so they are automatically handled above.  */
      gcc_assert (!VAR_P (decl)
		  || !DECL_VTABLE_OR_VTT_P (decl));

      if (DECL_FUNCTION_SCOPE_P (decl) && ! DECL_VISIBILITY_SPECIFIED (decl))
	{
	  /* Local statics and classes get the visibility of their
	     containing function by default, except that
	     -fvisibility-inlines-hidden doesn't affect them.  */
	  tree fn = DECL_CONTEXT (decl);
	  if (DECL_VISIBILITY_SPECIFIED (fn))
	    {
	      DECL_VISIBILITY (decl) = DECL_VISIBILITY (fn);
	      DECL_VISIBILITY_SPECIFIED (decl) = 
		DECL_VISIBILITY_SPECIFIED (fn);
	    }
	  else
	    {
	      if (DECL_CLASS_SCOPE_P (fn))
		determine_visibility_from_class (decl, DECL_CONTEXT (fn));
	      else if (determine_hidden_inline (fn))
		{
		  DECL_VISIBILITY (decl) = default_visibility;
		  DECL_VISIBILITY_SPECIFIED (decl) =
		    visibility_options.inpragma;
		}
	      else
		{
	          DECL_VISIBILITY (decl) = DECL_VISIBILITY (fn);
	          DECL_VISIBILITY_SPECIFIED (decl) =
		    DECL_VISIBILITY_SPECIFIED (fn);
		}
	    }

	  /* Local classes in templates have CLASSTYPE_USE_TEMPLATE set,
	     but have no TEMPLATE_INFO, so don't try to check it.  */
	  template_decl = NULL_TREE;
	}
      else if (VAR_P (decl) && DECL_TINFO_P (decl)
	       && flag_visibility_ms_compat)
	{
	  /* Under -fvisibility-ms-compat, types are visible by default,
	     even though their contents aren't.  */
	  tree underlying_type = TREE_TYPE (DECL_NAME (decl));
	  int underlying_vis = type_visibility (underlying_type);
	  if (underlying_vis == VISIBILITY_ANON
	      || (CLASS_TYPE_P (underlying_type)
		  && CLASSTYPE_VISIBILITY_SPECIFIED (underlying_type)))
	    constrain_visibility (decl, underlying_vis, false);
	  else
	    DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
	}
      else if (VAR_P (decl) && DECL_TINFO_P (decl))
	{
	  /* tinfo visibility is based on the type it's for.  */
	  constrain_visibility
	    (decl, type_visibility (TREE_TYPE (DECL_NAME (decl))), false);

	  /* Give the target a chance to override the visibility associated
	     with DECL.  */
	  if (TREE_PUBLIC (decl)
	      && !DECL_REALLY_EXTERN (decl)
	      && CLASS_TYPE_P (TREE_TYPE (DECL_NAME (decl)))
	      && !CLASSTYPE_VISIBILITY_SPECIFIED (TREE_TYPE (DECL_NAME (decl))))
	    targetm.cxx.determine_class_data_visibility (decl);
	}
      else if (template_decl)
	/* Template instantiations and specializations get visibility based
	   on their template unless they override it with an attribute.  */;
      else if (! DECL_VISIBILITY_SPECIFIED (decl))
	{
          if (determine_hidden_inline (decl))
	    DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
	  else
            {
	      /* Set default visibility to whatever the user supplied with
	         #pragma GCC visibility or a namespace visibility attribute.  */
	      DECL_VISIBILITY (decl) = default_visibility;
	      DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
            }
	}
    }

  if (template_decl)
    {
      /* If the specialization doesn't specify visibility, use the
	 visibility from the template.  */
      tree tinfo = get_template_info (template_decl);
      tree args = TI_ARGS (tinfo);
      tree attribs = (TREE_CODE (decl) == TYPE_DECL
		      ? TYPE_ATTRIBUTES (TREE_TYPE (decl))
		      : DECL_ATTRIBUTES (decl));
      tree attr = lookup_attribute ("visibility", attribs);
      
      if (args != error_mark_node)
	{
	  tree pattern = DECL_TEMPLATE_RESULT (TI_TEMPLATE (tinfo));

	  if (!DECL_VISIBILITY_SPECIFIED (decl))
	    {
	      if (!attr
		  && determine_hidden_inline (decl))
		DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
	      else
		{
	          DECL_VISIBILITY (decl) = DECL_VISIBILITY (pattern);
	          DECL_VISIBILITY_SPECIFIED (decl)
		    = DECL_VISIBILITY_SPECIFIED (pattern);
		}
	    }

	  if (args
	      /* Template argument visibility outweighs #pragma or namespace
		 visibility, but not an explicit attribute.  */
	      && !attr)
	    {
	      int depth = TMPL_ARGS_DEPTH (args);
	      if (DECL_VISIBILITY_SPECIFIED (decl))
		{
		  /* A class template member with explicit visibility
		     overrides the class visibility, so we need to apply
		     all the levels of template args directly.  */
		  int i;
		  for (i = 1; i <= depth; ++i)
		    {
		      tree lev = TMPL_ARGS_LEVEL (args, i);
		      constrain_visibility_for_template (decl, lev);
		    }
		}
	      else if (PRIMARY_TEMPLATE_P (TI_TEMPLATE (tinfo)))
		/* Limit visibility based on its template arguments.  */
		constrain_visibility_for_template (decl, args);
	    }
	}
    }

  if (class_type)
    determine_visibility_from_class (decl, class_type);

  if (decl_anon_ns_mem_p (decl))
    /* Names in an anonymous namespace get internal linkage.  */
    constrain_visibility (decl, VISIBILITY_ANON, false);
  else if (TREE_CODE (decl) != TYPE_DECL)
    {
      /* Propagate anonymity from type to decl.  */
      int tvis = type_visibility (TREE_TYPE (decl));
      if (tvis == VISIBILITY_ANON
	  || ! DECL_VISIBILITY_SPECIFIED (decl))
	constrain_visibility (decl, tvis, false);
    }
  else if (no_linkage_check (TREE_TYPE (decl), /*relaxed_p=*/true))
    /* DR 757: A type without linkage shall not be used as the type of a
       variable or function with linkage, unless
       o the variable or function has extern "C" linkage (7.5 [dcl.link]), or
       o the variable or function is not used (3.2 [basic.def.odr]) or is
       defined in the same translation unit.

       Since non-extern "C" decls need to be defined in the same
       translation unit, we can make the type internal.  */
    constrain_visibility (decl, VISIBILITY_ANON, false);

  /* If visibility changed and DECL already has DECL_RTL, ensure
     symbol flags are updated.  */
  if ((DECL_VISIBILITY (decl) != orig_visibility
       || DECL_VISIBILITY_SPECIFIED (decl) != orig_visibility_specified)
      && ((VAR_P (decl) && TREE_STATIC (decl))
	  || TREE_CODE (decl) == FUNCTION_DECL)
      && DECL_RTL_SET_P (decl))
    make_decl_rtl (decl);
}

/* By default, static data members and function members receive
   the visibility of their containing class.  */

static void
determine_visibility_from_class (tree decl, tree class_type)
{
  if (DECL_VISIBILITY_SPECIFIED (decl))
    return;

  if (determine_hidden_inline (decl))
    DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
  else
    {
      /* Default to the class visibility.  */
      DECL_VISIBILITY (decl) = CLASSTYPE_VISIBILITY (class_type);
      DECL_VISIBILITY_SPECIFIED (decl)
	= CLASSTYPE_VISIBILITY_SPECIFIED (class_type);
    }

  /* Give the target a chance to override the visibility associated
     with DECL.  */
  if (VAR_P (decl)
      && TREE_PUBLIC (decl)
      && (DECL_TINFO_P (decl) || DECL_VTABLE_OR_VTT_P (decl))
      && !DECL_REALLY_EXTERN (decl)
      && !CLASSTYPE_VISIBILITY_SPECIFIED (class_type))
    targetm.cxx.determine_class_data_visibility (decl);
}

/* Returns true iff DECL is an inline that should get hidden visibility
   because of -fvisibility-inlines-hidden.  */

static bool
determine_hidden_inline (tree decl)
{
  return (visibility_options.inlines_hidden
	  /* Don't do this for inline templates; specializations might not be
	     inline, and we don't want them to inherit the hidden
	     visibility.  We'll set it here for all inline instantiations.  */
	  && !processing_template_decl
	  && TREE_CODE (decl) == FUNCTION_DECL
	  && DECL_DECLARED_INLINE_P (decl)
	  && (! DECL_LANG_SPECIFIC (decl)
	      || ! DECL_EXPLICIT_INSTANTIATION (decl)));
}

/* Constrain the visibility of a class TYPE based on the visibility of its
   field types.  Warn if any fields require lesser visibility.  */

void
constrain_class_visibility (tree type)
{
  tree binfo;
  tree t;
  int i;

  int vis = type_visibility (type);

  if (vis == VISIBILITY_ANON
      || DECL_IN_SYSTEM_HEADER (TYPE_MAIN_DECL (type)))
    return;

  /* Don't warn about visibility if the class has explicit visibility.  */
  if (CLASSTYPE_VISIBILITY_SPECIFIED (type))
    vis = VISIBILITY_INTERNAL;

  for (t = TYPE_FIELDS (type); t; t = DECL_CHAIN (t))
    if (TREE_CODE (t) == FIELD_DECL && TREE_TYPE (t) != error_mark_node
	&& !DECL_ARTIFICIAL (t))
      {
	tree ftype = strip_pointer_or_array_types (TREE_TYPE (t));
	int subvis = type_visibility (ftype);

	if (subvis == VISIBILITY_ANON)
	  {
	    if (!in_main_input_context())
	      {
		tree nlt = no_linkage_check (ftype, /*relaxed_p=*/false);
		if (nlt)
		  {
		    if (same_type_p (TREE_TYPE (t), nlt))
		      warning (OPT_Wsubobject_linkage, "\
%qT has a field %qD whose type has no linkage",
			       type, t);
		    else
		      warning (OPT_Wsubobject_linkage, "\
%qT has a field %qD whose type depends on the type %qT which has no linkage",
			       type, t, nlt);
		  }
		else
		  warning (OPT_Wsubobject_linkage, "\
%qT has a field %qD whose type uses the anonymous namespace",
			   type, t);
	      }
	  }
	else if (MAYBE_CLASS_TYPE_P (ftype)
		 && vis < VISIBILITY_HIDDEN
		 && subvis >= VISIBILITY_HIDDEN)
	  warning (OPT_Wattributes, "\
%qT declared with greater visibility than the type of its field %qD",
		   type, t);
      }

  binfo = TYPE_BINFO (type);
  for (i = 0; BINFO_BASE_ITERATE (binfo, i, t); ++i)
    {
      int subvis = type_visibility (TREE_TYPE (t));

      if (subvis == VISIBILITY_ANON)
        {
	  if (!in_main_input_context())
	    {
	      tree nlt = no_linkage_check (TREE_TYPE (t), /*relaxed_p=*/false);
	      if (nlt)
		{
		  if (same_type_p (TREE_TYPE (t), nlt))
		    warning (OPT_Wsubobject_linkage, "\
%qT has a base %qT whose type has no linkage",
			     type, TREE_TYPE (t));
		  else
		    warning (OPT_Wsubobject_linkage, "\
%qT has a base %qT whose type depends on the type %qT which has no linkage",
			     type, TREE_TYPE (t), nlt);
		}
	      else
		warning (OPT_Wsubobject_linkage, "\
%qT has a base %qT whose type uses the anonymous namespace",
			 type, TREE_TYPE (t));
	    }
	}
      else if (vis < VISIBILITY_HIDDEN
	       && subvis >= VISIBILITY_HIDDEN)
	warning (OPT_Wattributes, "\
%qT declared with greater visibility than its base %qT",
		 type, TREE_TYPE (t));
    }
}

/* Functions for adjusting the visibility of a tagged type and its nested
   types and declarations when it gets a name for linkage purposes from a
   typedef.  */
// FIXME: It is now a DR for such a class type to contain anything
// other than C.  So at minium most of this can probably be deleted.

/* First reset the visibility of all the types.  */

static void
reset_type_linkage_1 (tree type)
{
  set_linkage_according_to_type (type, TYPE_MAIN_DECL (type));
  if (CLASS_TYPE_P (type))
    for (tree member = TYPE_FIELDS (type); member; member = DECL_CHAIN (member))
      if (DECL_IMPLICIT_TYPEDEF_P (member))
	reset_type_linkage_1 (TREE_TYPE (member));
}

/* Then reset the visibility of any static data members or member
   functions that use those types.  */

static void
reset_decl_linkage (tree decl)
{
  if (TREE_PUBLIC (decl))
    return;
  if (DECL_CLONED_FUNCTION_P (decl))
    return;
  TREE_PUBLIC (decl) = true;
  DECL_INTERFACE_KNOWN (decl) = false;
  determine_visibility (decl);
  tentative_decl_linkage (decl);
}

void
reset_type_linkage (tree type)
{
  reset_type_linkage_1 (type);
  if (CLASS_TYPE_P (type))
    {
      if (tree vt = CLASSTYPE_VTABLES (type))
	{
	  tree name = mangle_vtbl_for_type (type);
	  DECL_NAME (vt) = name;
	  SET_DECL_ASSEMBLER_NAME (vt, name);
	  reset_decl_linkage (vt);
	}
      if (!ANON_AGGR_TYPE_P (type))
	if (tree ti = CLASSTYPE_TYPEINFO_VAR (type))
	  {
	    tree name = mangle_typeinfo_for_type (type);
	    DECL_NAME (ti) = name;
	    SET_DECL_ASSEMBLER_NAME (ti, name);
	    TREE_TYPE (name) = type;
	    reset_decl_linkage (ti);
	  }
      for (tree m = TYPE_FIELDS (type); m; m = DECL_CHAIN (m))
	{
	  tree mem = STRIP_TEMPLATE (m);
	  if (TREE_CODE (mem) == VAR_DECL || TREE_CODE (mem) == FUNCTION_DECL)
	    reset_decl_linkage (mem);
	  else if (DECL_IMPLICIT_TYPEDEF_P (mem))
	    reset_type_linkage (TREE_TYPE (mem));
	}
    }
}

/* Set up our initial idea of what the linkage of DECL should be.  */

void
tentative_decl_linkage (tree decl)
{
  if (DECL_INTERFACE_KNOWN (decl))
    /* We've already made a decision as to how this function will
       be handled.  */;
  else if (vague_linkage_p (decl))
    {
      if (TREE_CODE (decl) == FUNCTION_DECL
	  && decl_defined_p (decl))
	{
	  DECL_EXTERNAL (decl) = 1;
	  DECL_NOT_REALLY_EXTERN (decl) = 1;
	  note_vague_linkage_fn (decl);
	  /* A non-template inline function with external linkage will
	     always be COMDAT.  As we must eventually determine the
	     linkage of all functions, and as that causes writes to
	     the data mapped in from the PCH file, it's advantageous
	     to mark the functions at this point.  */
	  if (DECL_DECLARED_INLINE_P (decl)
	      && (!DECL_IMPLICIT_INSTANTIATION (decl)
		  || DECL_DEFAULTED_FN (decl)))
	    {
	      /* This function must have external linkage, as
		 otherwise DECL_INTERFACE_KNOWN would have been
		 set.  */
	      gcc_assert (TREE_PUBLIC (decl));
	      comdat_linkage (decl);
	      DECL_INTERFACE_KNOWN (decl) = 1;
	    }
	}
      else if (VAR_P (decl))
	maybe_commonize_var (decl);
    }
}

/* DECL is a FUNCTION_DECL or VAR_DECL.  If the object file linkage
   for DECL has not already been determined, do so now by setting
   DECL_EXTERNAL, DECL_COMDAT and other related flags.  Until this
   function is called entities with vague linkage whose definitions
   are available must have TREE_PUBLIC set.

   If this function decides to place DECL in COMDAT, it will set
   appropriate flags -- but will not clear DECL_EXTERNAL.  It is up to
   the caller to decide whether or not to clear DECL_EXTERNAL.  Some
   callers defer that decision until it is clear that DECL is actually
   required.  */

void
import_export_decl (tree decl)
{
  bool comdat_p;
  bool import_p;
  tree class_type = NULL_TREE;

  if (DECL_INTERFACE_KNOWN (decl))
    return;

  /* We cannot determine what linkage to give to an entity with vague
     linkage until the end of the file.  For example, a virtual table
     for a class will be defined if and only if the key method is
     defined in this translation unit.  */
  gcc_assert (at_eof);
  /* Object file linkage for explicit instantiations is handled in
     mark_decl_instantiated.  For static variables in functions with
     vague linkage, maybe_commonize_var is used.

     Therefore, the only declarations that should be provided to this
     function are those with external linkage that are:

     * implicit instantiations of function templates

     * inline function

     * implicit instantiations of static data members of class
       templates

     * virtual tables

     * typeinfo objects

     Furthermore, all entities that reach this point must have a
     definition available in this translation unit.

     The following assertions check these conditions.  */
  gcc_assert (VAR_OR_FUNCTION_DECL_P (decl));
  /* Any code that creates entities with TREE_PUBLIC cleared should
     also set DECL_INTERFACE_KNOWN.  */
  gcc_assert (TREE_PUBLIC (decl));
  if (TREE_CODE (decl) == FUNCTION_DECL)
    gcc_assert (DECL_IMPLICIT_INSTANTIATION (decl)
		|| DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (decl)
		|| DECL_DECLARED_INLINE_P (decl));
  else
    gcc_assert (DECL_IMPLICIT_INSTANTIATION (decl)
		|| DECL_VTABLE_OR_VTT_P (decl)
		|| DECL_TINFO_P (decl));
  /* Check that a definition of DECL is available in this translation
     unit.  */
  gcc_assert (!DECL_REALLY_EXTERN (decl));

  /* Assume that DECL will not have COMDAT linkage.  */
  comdat_p = false;
  /* Assume that DECL will not be imported into this translation
     unit.  */
  import_p = false;

  if (VAR_P (decl) && DECL_VTABLE_OR_VTT_P (decl))
    {
      class_type = DECL_CONTEXT (decl);
      import_export_class (class_type);
      if (CLASSTYPE_INTERFACE_KNOWN (class_type)
	  && CLASSTYPE_INTERFACE_ONLY (class_type))
	import_p = true;
      else if ((!flag_weak || TARGET_WEAK_NOT_IN_ARCHIVE_TOC)
	       && !CLASSTYPE_USE_TEMPLATE (class_type)