diff gcc/cp/rtti.c @ 111:04ced10e8804

gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
parents
children 84e7813d76e9
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/cp/rtti.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,1646 @@
+/* RunTime Type Identification
+   Copyright (C) 1995-2017 Free Software Foundation, Inc.
+   Mostly written by Jason Merrill (jason@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/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "target.h"
+#include "cp-tree.h"
+#include "memmodel.h"
+#include "tm_p.h"
+#include "stringpool.h"
+#include "intl.h"
+#include "stor-layout.h"
+#include "c-family/c-pragma.h"
+#include "gcc-rich-location.h"
+
+/* C++ returns type information to the user in struct type_info
+   objects. We also use type information to implement dynamic_cast and
+   exception handlers. Type information for a particular type is
+   indicated with an ABI defined structure derived from type_info.
+   This would all be very straight forward, but for the fact that the
+   runtime library provides the definitions of the type_info structure
+   and the ABI defined derived classes. We cannot build declarations
+   of them directly in the compiler, but we need to layout objects of
+   their type.  Somewhere we have to lie.
+
+   We define layout compatible POD-structs with compiler-defined names
+   and generate the appropriate initializations for them (complete
+   with explicit mention of their vtable). When we have to provide a
+   type_info to the user we reinterpret_cast the internal compiler
+   type to type_info.  A well formed program can only explicitly refer
+   to the type_infos of complete types (& cv void).  However, we chain
+   pointer type_infos to the pointed-to-type, and that can be
+   incomplete.  We only need the addresses of such incomplete
+   type_info objects for static initialization.
+
+   The type information VAR_DECL of a type is held on the
+   get_global_binding of the type's mangled name. That VAR_DECL
+   will be the internal type.  It will usually have the correct
+   internal type reflecting the kind of type it represents (pointer,
+   array, function, class, inherited class, etc).  When the type it
+   represents is incomplete, it will have the internal type
+   corresponding to type_info.  That will only happen at the end of
+   translation, when we are emitting the type info objects.  */
+
+/* Auxiliary data we hold for each type_info derived object we need.  */
+struct GTY (()) tinfo_s {
+  tree type;  /* The RECORD_TYPE for this type_info object */
+
+  tree vtable; /* The VAR_DECL of the vtable.  Only filled at end of
+		  translation.  */
+
+  tree name;  /* IDENTIFIER_NODE for the ABI specified name of
+		 the type_info derived type.  */
+};
+
+
+enum tinfo_kind
+{
+  TK_TYPE_INFO_TYPE,    /* abi::__type_info_pseudo */
+  TK_BASE_TYPE,		/* abi::__base_class_type_info */
+  TK_DERIVED_TYPES,	/* Start of types derived from abi::__type_info  */
+  TK_BUILTIN_TYPE = TK_DERIVED_TYPES,	/* abi::__fundamental_type_info */
+  TK_ARRAY_TYPE,	/* abi::__array_type_info */
+  TK_FUNCTION_TYPE,	/* abi::__function_type_info */
+  TK_ENUMERAL_TYPE,	/* abi::__enum_type_info */
+  TK_POINTER_TYPE,	/* abi::__pointer_type_info */
+  TK_POINTER_MEMBER_TYPE, /* abi::__pointer_to_member_type_info */
+  TK_CLASS_TYPE,	/* abi::__class_type_info */
+  TK_SI_CLASS_TYPE,	/* abi::__si_class_type_info */
+  TK_VMI_CLASS_TYPES,	/* abi::__vmi_class_type_info<int> */
+  TK_MAX
+};
+
+/* Names of the tinfo types.  Must be same order as TK enumeration
+   above.  */
+
+static const char *const tinfo_names[TK_MAX] =
+{
+  "__type_info",
+  "__base_class_type_info",
+  "__fundamental_type_info",
+  "__array_type_info",
+  "__function_type_info",
+  "__enum_type_info",
+  "__pointer_type_info",
+  "__pointer_to_member_type_info",
+  "__class_type_info",
+  "__si_class_type_info",
+  "__vmi_class_type_info"
+};
+
+/* Helper macro to get maximum scalar-width of pointer or of the 'long'-type.
+   This of interest for llp64 targets.  */
+#define LONGPTR_T \
+  integer_types[(POINTER_SIZE <= TYPE_PRECISION (integer_types[itk_long]) \
+		 ? itk_long : itk_long_long)]
+
+/* A vector of all tinfo decls that haven't yet been emitted.  */
+vec<tree, va_gc> *unemitted_tinfo_decls;
+
+/* A vector of all type_info derived types we need.  The first few are
+   fixed and created early. The remainder are for multiple inheritance
+   and are generated as needed. */
+static GTY (()) vec<tinfo_s, va_gc> *tinfo_descs;
+
+static tree ifnonnull (tree, tree, tsubst_flags_t);
+static tree tinfo_name (tree, bool);
+static tree build_dynamic_cast_1 (tree, tree, tsubst_flags_t);
+static tree throw_bad_cast (void);
+static tree throw_bad_typeid (void);
+static tree get_tinfo_ptr (tree);
+static bool typeid_ok_p (void);
+static int qualifier_flags (tree);
+static bool target_incomplete_p (tree);
+static tree tinfo_base_init (tinfo_s *, tree);
+static tree generic_initializer (tinfo_s *, tree);
+static tree ptr_initializer (tinfo_s *, tree);
+static tree ptm_initializer (tinfo_s *, tree);
+static tree class_initializer (tinfo_s *, tree, unsigned, ...);
+static tree get_pseudo_ti_init (tree, unsigned);
+static unsigned get_pseudo_ti_index (tree);
+static tinfo_s *get_tinfo_desc (unsigned);
+static void create_tinfo_types (void);
+static bool typeinfo_in_lib_p (tree);
+
+static int doing_runtime = 0;
+
+static void
+push_abi_namespace (void)
+{
+  push_nested_namespace (abi_node);
+  push_visibility ("default", 2);
+}
+
+static void
+pop_abi_namespace (void)
+{
+  pop_visibility (2);
+  pop_nested_namespace (abi_node);
+}
+
+/* Declare language defined type_info type and a pointer to const
+   type_info.  This is incomplete here, and will be completed when
+   the user #includes <typeinfo>.  There are language defined
+   restrictions on what can be done until that is included.  Create
+   the internal versions of the ABI types.  */
+
+void
+init_rtti_processing (void)
+{
+  tree type_info_type;
+
+  push_namespace (std_identifier);
+  type_info_type = xref_tag (class_type, get_identifier ("type_info"),
+			     /*tag_scope=*/ts_current, false);
+  pop_namespace ();
+  const_type_info_type_node
+    = cp_build_qualified_type (type_info_type, TYPE_QUAL_CONST);
+  type_info_ptr_type = build_pointer_type (const_type_info_type_node);
+
+  vec_alloc (unemitted_tinfo_decls, 124);
+
+  create_tinfo_types ();
+}
+
+/* Given the expression EXP of type `class *', return the head of the
+   object pointed to by EXP with type cv void*, if the class has any
+   virtual functions (TYPE_POLYMORPHIC_P), else just return the
+   expression.  */
+
+tree
+build_headof (tree exp)
+{
+  tree type = TREE_TYPE (exp);
+  tree offset;
+  tree index;
+
+  gcc_assert (TYPE_PTR_P (type));
+  type = TREE_TYPE (type);
+
+  if (!TYPE_POLYMORPHIC_P (type))
+    return exp;
+
+  /* We use this a couple of times below, protect it.  */
+  exp = save_expr (exp);
+
+  /* The offset-to-top field is at index -2 from the vptr.  */
+  index = build_int_cst (NULL_TREE,
+			 -2 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
+
+  offset = build_vtbl_ref (cp_build_indirect_ref (exp, RO_NULL, 
+                                                  tf_warning_or_error), 
+                           index);
+
+  type = cp_build_qualified_type (ptr_type_node,
+				  cp_type_quals (TREE_TYPE (exp)));
+  return fold_build_pointer_plus (exp, offset);
+}
+
+/* Get a bad_cast node for the program to throw...
+
+   See libstdc++/exception.cc for __throw_bad_cast */
+
+static tree
+throw_bad_cast (void)
+{
+  static tree fn;
+  if (!fn)
+    {
+      tree name = get_identifier ("__cxa_bad_cast");
+      fn = get_global_binding (name);
+      if (!fn)
+	fn = push_throw_library_fn
+	  (name, build_function_type_list (ptr_type_node, NULL_TREE));
+    }
+
+  return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
+}
+
+/* Return an expression for "__cxa_bad_typeid()".  The expression
+   returned is an lvalue of type "const std::type_info".  */
+
+static tree
+throw_bad_typeid (void)
+{
+  static tree fn;
+  if (!fn)
+    {
+      tree name = get_identifier ("__cxa_bad_typeid");
+      fn = get_global_binding (name);
+      if (!fn)
+	{
+	  tree t = build_reference_type (const_type_info_type_node);
+	  t = build_function_type_list (t, NULL_TREE);
+	  fn = push_throw_library_fn (name, t);
+	}
+    }
+
+  return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
+}
+
+/* Return an lvalue expression whose type is "const std::type_info"
+   and whose value indicates the type of the expression EXP.  If EXP
+   is a reference to a polymorphic class, return the dynamic type;
+   otherwise return the static type of the expression.  */
+
+static tree
+get_tinfo_decl_dynamic (tree exp, tsubst_flags_t complain)
+{
+  tree type;
+  tree t;
+
+  if (error_operand_p (exp))
+    return error_mark_node;
+
+  exp = resolve_nondeduced_context (exp, complain);
+
+  /* peel back references, so they match.  */
+  type = non_reference (TREE_TYPE (exp));
+
+  /* Peel off cv qualifiers.  */
+  type = TYPE_MAIN_VARIANT (type);
+
+  /* For UNKNOWN_TYPEs call complete_type_or_else to get diagnostics.  */
+  if (CLASS_TYPE_P (type) || type == unknown_type_node
+      || type == init_list_type_node)
+    type = complete_type_or_maybe_complain (type, exp, complain);
+
+  if (!type)
+    return error_mark_node;
+
+  /* If exp is a reference to polymorphic type, get the real type_info.  */
+  if (TYPE_POLYMORPHIC_P (type) && ! resolves_to_fixed_type_p (exp, 0))
+    {
+      /* build reference to type_info from vtable.  */
+      tree index;
+
+      /* The RTTI information is at index -1.  */
+      index = build_int_cst (NULL_TREE,
+			     -1 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
+      t = build_vtbl_ref (exp, index);
+      t = convert (type_info_ptr_type, t);
+    }
+  else
+    /* Otherwise return the type_info for the static type of the expr.  */
+    t = get_tinfo_ptr (TYPE_MAIN_VARIANT (type));
+
+  return cp_build_indirect_ref (t, RO_NULL, complain);
+}
+
+static bool
+typeid_ok_p (void)
+{
+  if (! flag_rtti)
+    {
+      error ("cannot use %<typeid%> with -fno-rtti");
+      return false;
+    }
+
+  if (!COMPLETE_TYPE_P (const_type_info_type_node))
+    {
+      gcc_rich_location richloc (input_location);
+      maybe_add_include_fixit (&richloc, "<typeinfo>");
+      error_at_rich_loc (&richloc,
+			 "must %<#include <typeinfo>%> before using"
+			 " %<typeid%>");
+
+      return false;
+    }
+
+  tree pseudo = TYPE_MAIN_VARIANT (get_tinfo_desc (TK_TYPE_INFO_TYPE)->type);
+  tree real = TYPE_MAIN_VARIANT (const_type_info_type_node);
+
+  /* Make sure abi::__type_info_pseudo has the same alias set
+     as std::type_info.  */
+  if (! TYPE_ALIAS_SET_KNOWN_P (pseudo))
+    TYPE_ALIAS_SET (pseudo) = get_alias_set (real);
+  else
+    gcc_assert (TYPE_ALIAS_SET (pseudo) == get_alias_set (real));
+
+  return true;
+}
+
+/* Return an expression for "typeid(EXP)".  The expression returned is
+   an lvalue of type "const std::type_info".  */
+
+tree
+build_typeid (tree exp, tsubst_flags_t complain)
+{
+  tree cond = NULL_TREE, initial_expr = exp;
+  int nonnull = 0;
+
+  if (exp == error_mark_node || !typeid_ok_p ())
+    return error_mark_node;
+
+  if (processing_template_decl)
+    return build_min (TYPEID_EXPR, const_type_info_type_node, exp);
+
+  /* FIXME when integrating with c_fully_fold, mark
+     resolves_to_fixed_type_p case as a non-constant expression.  */
+  if (TYPE_POLYMORPHIC_P (TREE_TYPE (exp))
+      && ! resolves_to_fixed_type_p (exp, &nonnull)
+      && ! nonnull)
+    {
+      /* So we need to look into the vtable of the type of exp.
+         Make sure it isn't a null lvalue.  */
+      exp = cp_build_addr_expr (exp, complain);
+      exp = save_expr (exp);
+      cond = cp_convert (boolean_type_node, exp, complain);
+      exp = cp_build_indirect_ref (exp, RO_NULL, complain);
+    }
+
+  exp = get_tinfo_decl_dynamic (exp, complain);
+
+  if (exp == error_mark_node)
+    return error_mark_node;
+
+  if (cond)
+    {
+      tree bad = throw_bad_typeid ();
+
+      exp = build3 (COND_EXPR, TREE_TYPE (exp), cond, exp, bad);
+    }
+  else
+    mark_type_use (initial_expr);
+
+  return exp;
+}
+
+/* Generate the NTBS name of a type.  If MARK_PRIVATE, put a '*' in front so that
+   comparisons will be done by pointer rather than string comparison.  */
+static tree
+tinfo_name (tree type, bool mark_private)
+{
+  const char *name;
+  int length;
+  tree name_string;
+
+  name = mangle_type_string (type);
+  length = strlen (name);
+
+  if (mark_private)
+    {
+      /* Inject '*' at beginning of name to force pointer comparison.  */
+      char* buf = (char*) XALLOCAVEC (char, length + 2);
+      buf[0] = '*';
+      memcpy (buf + 1, name, length + 1);
+      name_string = build_string (length + 2, buf);
+    }
+  else
+    name_string = build_string (length + 1, name);
+
+  return fix_string_type (name_string);
+}
+
+/* Return a VAR_DECL for the internal ABI defined type_info object for
+   TYPE. You must arrange that the decl is mark_used, if actually use
+   it --- decls in vtables are only used if the vtable is output.  */
+
+tree
+get_tinfo_decl (tree type)
+{
+  tree name;
+  tree d;
+
+  if (variably_modified_type_p (type, /*fn=*/NULL_TREE))
+    {
+      error ("cannot create type information for type %qT because "
+	     "it involves types of variable size",
+	     type);
+      return error_mark_node;
+    }
+
+  if (TREE_CODE (type) == METHOD_TYPE)
+    type = build_function_type (TREE_TYPE (type),
+				TREE_CHAIN (TYPE_ARG_TYPES (type)));
+
+  type = complete_type (type);
+
+  /* For a class type, the variable is cached in the type node
+     itself.  */
+  if (CLASS_TYPE_P (type))
+    {
+      d = CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type));
+      if (d)
+	return d;
+    }
+
+  name = mangle_typeinfo_for_type (type);
+
+  d = get_global_binding (name);
+  if (!d)
+    {
+      int ix = get_pseudo_ti_index (type);
+      const tinfo_s *ti = get_tinfo_desc (ix);
+      
+      d = build_lang_decl (VAR_DECL, name, ti->type);
+      SET_DECL_ASSEMBLER_NAME (d, name);
+      /* Remember the type it is for.  */
+      TREE_TYPE (name) = type;
+      DECL_TINFO_P (d) = 1;
+      DECL_ARTIFICIAL (d) = 1;
+      DECL_IGNORED_P (d) = 1;
+      TREE_READONLY (d) = 1;
+      TREE_STATIC (d) = 1;
+      /* Mark the variable as undefined -- but remember that we can
+	 define it later if we need to do so.  */
+      DECL_EXTERNAL (d) = 1;
+      DECL_NOT_REALLY_EXTERN (d) = 1;
+      set_linkage_according_to_type (type, d);
+
+      d = pushdecl_top_level_and_finish (d, NULL_TREE);
+      if (CLASS_TYPE_P (type))
+	CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type)) = d;
+
+      /* Add decl to the global array of tinfo decls.  */
+      vec_safe_push (unemitted_tinfo_decls, d);
+    }
+
+  return d;
+}
+
+/* Return a pointer to a type_info object describing TYPE, suitably
+   cast to the language defined type.  */
+
+static tree
+get_tinfo_ptr (tree type)
+{
+  tree decl = get_tinfo_decl (type);
+
+  mark_used (decl);
+  return build_nop (type_info_ptr_type,
+		    build_address (decl));
+}
+
+/* Return the type_info object for TYPE.  */
+
+tree
+get_typeid (tree type, tsubst_flags_t complain)
+{
+  if (type == error_mark_node || !typeid_ok_p ())
+    return error_mark_node;
+
+  if (processing_template_decl)
+    return build_min (TYPEID_EXPR, const_type_info_type_node, type);
+
+  /* If the type of the type-id is a reference type, the result of the
+     typeid expression refers to a type_info object representing the
+     referenced type.  */
+  type = non_reference (type);
+
+  /* This is not one of the uses of a qualified function type in 8.3.5.  */
+  if (TREE_CODE (type) == FUNCTION_TYPE
+      && (type_memfn_quals (type) != TYPE_UNQUALIFIED
+	  || type_memfn_rqual (type) != REF_QUAL_NONE))
+    {
+      if (complain & tf_error)
+	error ("typeid of qualified function type %qT", type);
+      return error_mark_node;
+    }
+
+  /* The top-level cv-qualifiers of the lvalue expression or the type-id
+     that is the operand of typeid are always ignored.  */
+  type = TYPE_MAIN_VARIANT (type);
+
+  /* For UNKNOWN_TYPEs call complete_type_or_else to get diagnostics.  */
+  if (CLASS_TYPE_P (type) || type == unknown_type_node
+      || type == init_list_type_node)
+    type = complete_type_or_maybe_complain (type, NULL_TREE, complain);
+
+  if (!type)
+    return error_mark_node;
+
+  return cp_build_indirect_ref (get_tinfo_ptr (type), RO_NULL, complain);
+}
+
+/* Check whether TEST is null before returning RESULT.  If TEST is used in
+   RESULT, it must have previously had a save_expr applied to it.  */
+
+static tree
+ifnonnull (tree test, tree result, tsubst_flags_t complain)
+{
+  tree cond = build2 (NE_EXPR, boolean_type_node, test,
+		      cp_convert (TREE_TYPE (test), nullptr_node, complain));
+  /* This is a compiler generated comparison, don't emit
+     e.g. -Wnonnull-compare warning for it.  */
+  TREE_NO_WARNING (cond) = 1;
+  return build3 (COND_EXPR, TREE_TYPE (result), cond, result,
+		 cp_convert (TREE_TYPE (result), nullptr_node, complain));
+}
+
+/* Execute a dynamic cast, as described in section 5.2.6 of the 9/93 working
+   paper.  */
+
+static tree
+build_dynamic_cast_1 (tree type, tree expr, tsubst_flags_t complain)
+{
+  enum tree_code tc = TREE_CODE (type);
+  tree exprtype;
+  tree dcast_fn;
+  tree old_expr = expr;
+  const char *errstr = NULL;
+
+  /* Save casted types in the function's used types hash table.  */
+  used_types_insert (type);
+
+  /* T shall be a pointer or reference to a complete class type, or
+     `pointer to cv void''.  */
+  switch (tc)
+    {
+    case POINTER_TYPE:
+      if (VOID_TYPE_P (TREE_TYPE (type)))
+	break;
+      /* Fall through.  */
+    case REFERENCE_TYPE:
+      if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (type)))
+	{
+	  errstr = _("target is not pointer or reference to class");
+	  goto fail;
+	}
+      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (type))))
+	{
+	  errstr = _("target is not pointer or reference to complete type");
+	  goto fail;
+	}
+      break;
+
+    default:
+      errstr = _("target is not pointer or reference");
+      goto fail;
+    }
+
+  if (tc == POINTER_TYPE)
+    {
+      expr = decay_conversion (expr, complain);
+      exprtype = TREE_TYPE (expr);
+
+      /* If T is a pointer type, v shall be an rvalue of a pointer to
+	 complete class type, and the result is an rvalue of type T.  */
+
+      expr = mark_rvalue_use (expr);
+
+      if (!TYPE_PTR_P (exprtype))
+	{
+	  errstr = _("source is not a pointer");
+	  goto fail;
+	}
+      if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (exprtype)))
+	{
+	  errstr = _("source is not a pointer to class");
+	  goto fail;
+	}
+      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
+	{
+	  errstr = _("source is a pointer to incomplete type");
+	  goto fail;
+	}
+    }
+  else
+    {
+      expr = mark_lvalue_use (expr);
+
+      exprtype = build_reference_type (TREE_TYPE (expr));
+
+      /* T is a reference type, v shall be an lvalue of a complete class
+	 type, and the result is an lvalue of the type referred to by T.  */
+
+      if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (exprtype)))
+	{
+	  errstr = _("source is not of class type");
+	  goto fail;
+	}
+      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
+	{
+	  errstr = _("source is of incomplete class type");
+	  goto fail;
+	}
+    }
+
+  /* The dynamic_cast operator shall not cast away constness.  */
+  if (!at_least_as_qualified_p (TREE_TYPE (type),
+				TREE_TYPE (exprtype)))
+    {
+      errstr = _("conversion casts away constness");
+      goto fail;
+    }
+
+  /* If *type is an unambiguous accessible base class of *exprtype,
+     convert statically.  */
+  {
+    tree binfo = lookup_base (TREE_TYPE (exprtype), TREE_TYPE (type),
+			      ba_check, NULL, complain);
+    if (binfo)
+      return build_static_cast (type, expr, complain);
+  }
+
+  /* Apply trivial conversion T -> T& for dereferenced ptrs.  */
+  if (tc == REFERENCE_TYPE)
+    expr = convert_to_reference (exprtype, expr, CONV_IMPLICIT,
+				 LOOKUP_NORMAL, NULL_TREE, complain);
+
+  /* Otherwise *exprtype must be a polymorphic class (have a vtbl).  */
+  if (TYPE_POLYMORPHIC_P (TREE_TYPE (exprtype)))
+    {
+      tree expr1;
+      /* if TYPE is `void *', return pointer to complete object.  */
+      if (tc == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (type)))
+	{
+	  /* if b is an object, dynamic_cast<void *>(&b) == (void *)&b.  */
+	  if (TREE_CODE (expr) == ADDR_EXPR
+	      && VAR_P (TREE_OPERAND (expr, 0))
+	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == RECORD_TYPE)
+	    return build1 (NOP_EXPR, type, expr);
+
+	  /* Since expr is used twice below, save it.  */
+	  expr = save_expr (expr);
+
+	  expr1 = build_headof (expr);
+	  if (TREE_TYPE (expr1) != type)
+	    expr1 = build1 (NOP_EXPR, type, expr1);
+	  return ifnonnull (expr, expr1, complain);
+	}
+      else
+	{
+	  tree retval;
+	  tree result, td2, td3;
+	  tree elems[4];
+	  tree static_type, target_type, boff;
+
+	  /* If we got here, we can't convert statically.  Therefore,
+	     dynamic_cast<D&>(b) (b an object) cannot succeed.  */
+	  if (tc == REFERENCE_TYPE)
+	    {
+	      if (VAR_P (old_expr)
+		  && TREE_CODE (TREE_TYPE (old_expr)) == RECORD_TYPE)
+		{
+		  tree expr = throw_bad_cast ();
+                  if (complain & tf_warning)
+                    warning (0, "dynamic_cast of %q#D to %q#T can never succeed",
+                             old_expr, type);
+		  /* Bash it to the expected type.  */
+		  TREE_TYPE (expr) = type;
+		  return expr;
+		}
+	    }
+	  /* Ditto for dynamic_cast<D*>(&b).  */
+	  else if (TREE_CODE (expr) == ADDR_EXPR)
+	    {
+	      tree op = TREE_OPERAND (expr, 0);
+	      if (VAR_P (op)
+		  && TREE_CODE (TREE_TYPE (op)) == RECORD_TYPE)
+		{
+                  if (complain & tf_warning)
+                    warning (0, "dynamic_cast of %q#D to %q#T can never succeed",
+                             op, type);
+		  retval = build_int_cst (type, 0);
+		  return retval;
+		}
+	    }
+
+	  /* Use of dynamic_cast when -fno-rtti is prohibited.  */
+	  if (!flag_rtti)
+	    {
+              if (complain & tf_error)
+                error ("%<dynamic_cast%> not permitted with -fno-rtti");
+	      return error_mark_node;
+	    }
+
+	  target_type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
+	  static_type = TYPE_MAIN_VARIANT (TREE_TYPE (exprtype));
+	  td2 = get_tinfo_decl (target_type);
+	  if (!mark_used (td2, complain) && !(complain & tf_error))
+	    return error_mark_node;
+	  td2 = cp_build_addr_expr (td2, complain);
+	  td3 = get_tinfo_decl (static_type);
+	  if (!mark_used (td3, complain) && !(complain & tf_error))
+	    return error_mark_node;
+	  td3 = cp_build_addr_expr (td3, complain);
+
+	  /* Determine how T and V are related.  */
+	  boff = dcast_base_hint (static_type, target_type);
+
+	  /* Since expr is used twice below, save it.  */
+	  expr = save_expr (expr);
+
+	  expr1 = expr;
+	  if (tc == REFERENCE_TYPE)
+	    expr1 = cp_build_addr_expr (expr1, complain);
+
+	  elems[0] = expr1;
+	  elems[1] = td3;
+	  elems[2] = td2;
+	  elems[3] = boff;
+
+	  dcast_fn = dynamic_cast_node;
+	  if (!dcast_fn)
+	    {
+	      tree tmp;
+	      tree tinfo_ptr;
+	      const char *name;
+
+	      push_abi_namespace ();
+	      tinfo_ptr = xref_tag (class_type,
+				    get_identifier ("__class_type_info"),
+				    /*tag_scope=*/ts_current, false);
+
+	      tinfo_ptr = build_pointer_type
+		(cp_build_qualified_type
+		 (tinfo_ptr, TYPE_QUAL_CONST));
+	      name = "__dynamic_cast";
+	      tmp = build_function_type_list (ptr_type_node,
+					      const_ptr_type_node,
+					      tinfo_ptr, tinfo_ptr,
+					      ptrdiff_type_node, NULL_TREE);
+	      dcast_fn = build_library_fn_ptr (name, tmp,
+					       ECF_LEAF | ECF_PURE | ECF_NOTHROW);
+	      pop_abi_namespace ();
+	      dynamic_cast_node = dcast_fn;
+	    }
+	  result = build_cxx_call (dcast_fn, 4, elems, complain);
+
+	  if (tc == REFERENCE_TYPE)
+	    {
+	      tree bad = throw_bad_cast ();
+	      tree neq;
+
+	      result = save_expr (result);
+	      neq = cp_truthvalue_conversion (result);
+	      return cp_convert (type,
+				 build3 (COND_EXPR, TREE_TYPE (result),
+					 neq, result, bad), complain);
+	    }
+
+	  /* Now back to the type we want from a void*.  */
+	  result = cp_convert (type, result, complain);
+	  return ifnonnull (expr, result, complain);
+	}
+    }
+  else
+    errstr = _("source type is not polymorphic");
+
+ fail:
+  if (complain & tf_error)
+    error ("cannot dynamic_cast %qE (of type %q#T) to type %q#T (%s)",
+           old_expr, TREE_TYPE (old_expr), type, errstr);
+  return error_mark_node;
+}
+
+tree
+build_dynamic_cast (tree type, tree expr, tsubst_flags_t complain)
+{
+  tree r;
+
+  if (type == error_mark_node || expr == error_mark_node)
+    return error_mark_node;
+
+  if (processing_template_decl)
+    {
+      expr = build_min (DYNAMIC_CAST_EXPR, type, expr);
+      TREE_SIDE_EFFECTS (expr) = 1;
+      return convert_from_reference (expr);
+    }
+
+  r = convert_from_reference (build_dynamic_cast_1 (type, expr, complain));
+  if (r != error_mark_node)
+    maybe_warn_about_useless_cast (type, expr, complain);
+  return r;
+}
+
+/* Return the runtime bit mask encoding the qualifiers of TYPE.  */
+
+static int
+qualifier_flags (tree type)
+{
+  int flags = 0;
+  int quals = cp_type_quals (type);
+
+  if (quals & TYPE_QUAL_CONST)
+    flags |= 1;
+  if (quals & TYPE_QUAL_VOLATILE)
+    flags |= 2;
+  if (quals & TYPE_QUAL_RESTRICT)
+    flags |= 4;
+  return flags;
+}
+
+/* Return true, if the pointer chain TYPE ends at an incomplete type, or
+   contains a pointer to member of an incomplete class.  */
+
+static bool
+target_incomplete_p (tree type)
+{
+  while (true)
+    if (TYPE_PTRDATAMEM_P (type))
+      {
+	if (!COMPLETE_TYPE_P (TYPE_PTRMEM_CLASS_TYPE (type)))
+	  return true;
+	type = TYPE_PTRMEM_POINTED_TO_TYPE (type);
+      }
+    else if (TYPE_PTR_P (type))
+      type = TREE_TYPE (type);
+    else
+      return !COMPLETE_OR_VOID_TYPE_P (type);
+}
+
+/* Returns true if TYPE involves an incomplete class type; in that
+   case, typeinfo variables for TYPE should be emitted with internal
+   linkage.  */
+
+static bool
+involves_incomplete_p (tree type)
+{
+  switch (TREE_CODE (type))
+    {
+    case POINTER_TYPE:
+      return target_incomplete_p (TREE_TYPE (type));
+
+    case OFFSET_TYPE:
+    ptrmem:
+      return
+	(target_incomplete_p (TYPE_PTRMEM_POINTED_TO_TYPE (type))
+	 || !COMPLETE_TYPE_P (TYPE_PTRMEM_CLASS_TYPE (type)));
+
+    case RECORD_TYPE:
+      if (TYPE_PTRMEMFUNC_P (type))
+	goto ptrmem;
+      /* Fall through.  */
+    case UNION_TYPE:
+      if (!COMPLETE_TYPE_P (type))
+	return true;
+      /* Fall through.  */
+    default:
+      /* All other types do not involve incomplete class types.  */
+      return false;
+    }
+}
+
+/* Return a CONSTRUCTOR for the common part of the type_info objects. This
+   is the vtable pointer and NTBS name.  The NTBS name is emitted as a
+   comdat const char array, so it becomes a unique key for the type. Generate
+   and emit that VAR_DECL here.  (We can't always emit the type_info itself
+   as comdat, because of pointers to incomplete.) */
+
+static tree
+tinfo_base_init (tinfo_s *ti, tree target)
+{
+  tree init;
+  tree name_decl;
+  tree vtable_ptr;
+  vec<constructor_elt, va_gc> *v;
+
+  {
+    tree name_name, name_string;
+
+    /* Generate the NTBS array variable.  */
+    tree name_type = build_cplus_array_type
+		     (cp_build_qualified_type (char_type_node, TYPE_QUAL_CONST),
+		     NULL_TREE);
+
+    /* Determine the name of the variable -- and remember with which
+       type it is associated.  */
+    name_name = mangle_typeinfo_string_for_type (target);
+    TREE_TYPE (name_name) = target;
+
+    name_decl = build_lang_decl (VAR_DECL, name_name, name_type);
+    SET_DECL_ASSEMBLER_NAME (name_decl, name_name);
+    DECL_ARTIFICIAL (name_decl) = 1;
+    DECL_IGNORED_P (name_decl) = 1;
+    TREE_READONLY (name_decl) = 1;
+    TREE_STATIC (name_decl) = 1;
+    DECL_EXTERNAL (name_decl) = 0;
+    DECL_TINFO_P (name_decl) = 1;
+    set_linkage_according_to_type (target, name_decl);
+    import_export_decl (name_decl);
+    name_string = tinfo_name (target, !TREE_PUBLIC (name_decl));
+    DECL_INITIAL (name_decl) = name_string;
+    mark_used (name_decl);
+    pushdecl_top_level_and_finish (name_decl, name_string);
+  }
+
+  vtable_ptr = ti->vtable;
+  if (!vtable_ptr)
+    {
+      tree real_type;
+      push_abi_namespace ();
+      real_type = xref_tag (class_type, ti->name,
+			    /*tag_scope=*/ts_current, false);
+      pop_abi_namespace ();
+
+      if (!COMPLETE_TYPE_P (real_type))
+	{
+	  /* We never saw a definition of this type, so we need to
+	     tell the compiler that this is an exported class, as
+	     indeed all of the __*_type_info classes are.  */
+	  SET_CLASSTYPE_INTERFACE_KNOWN (real_type);
+	  CLASSTYPE_INTERFACE_ONLY (real_type) = 1;
+	}
+
+      vtable_ptr = get_vtable_decl (real_type, /*complete=*/1);
+      vtable_ptr = cp_build_addr_expr (vtable_ptr, tf_warning_or_error);
+
+      /* We need to point into the middle of the vtable.  */
+      vtable_ptr = fold_build_pointer_plus
+	(vtable_ptr,
+	 size_binop (MULT_EXPR,
+		     size_int (2 * TARGET_VTABLE_DATA_ENTRY_DISTANCE),
+		     TYPE_SIZE_UNIT (vtable_entry_type)));
+
+      ti->vtable = vtable_ptr;
+    }
+
+  vec_alloc (v, 2);
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, vtable_ptr);
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
+			  decay_conversion (name_decl, tf_warning_or_error));
+
+  init = build_constructor (init_list_type_node, v);
+  TREE_CONSTANT (init) = 1;
+  TREE_STATIC (init) = 1;
+
+  return init;
+}
+
+/* Return the CONSTRUCTOR expr for a type_info of TYPE. TI provides the
+   information about the particular type_info derivation, which adds no
+   additional fields to the type_info base.  */
+
+static tree
+generic_initializer (tinfo_s *ti, tree target)
+{
+  tree init = tinfo_base_init (ti, target);
+
+  init = build_constructor_single (init_list_type_node, NULL_TREE, init);
+  TREE_CONSTANT (init) = 1;
+  TREE_STATIC (init) = 1;
+  return init;
+}
+
+/* Return the CONSTRUCTOR expr for a type_info of pointer TYPE.
+   TI provides information about the particular type_info derivation,
+   which adds target type and qualifier flags members to the type_info base.  */
+
+static tree
+ptr_initializer (tinfo_s *ti, tree target)
+{
+  tree init = tinfo_base_init (ti, target);
+  tree to = TREE_TYPE (target);
+  int flags = qualifier_flags (to);
+  bool incomplete = target_incomplete_p (to);
+  vec<constructor_elt, va_gc> *v;
+  vec_alloc (v, 3);
+
+  if (incomplete)
+    flags |= 8;
+  if (tx_safe_fn_type_p (to))
+    {
+      flags |= 0x20;
+      to = tx_unsafe_fn_variant (to);
+    }
+  if (flag_noexcept_type
+      && (TREE_CODE (to) == FUNCTION_TYPE
+	  || TREE_CODE (to) == METHOD_TYPE)
+      && TYPE_NOTHROW_P (to))
+    {
+      flags |= 0x40;
+      to = build_exception_variant (to, NULL_TREE);
+    }
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init);
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, build_int_cst (NULL_TREE, flags));
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
+                          get_tinfo_ptr (TYPE_MAIN_VARIANT (to)));
+
+  init = build_constructor (init_list_type_node, v);
+  TREE_CONSTANT (init) = 1;
+  TREE_STATIC (init) = 1;
+  return init;
+}
+
+/* Return the CONSTRUCTOR expr for a type_info of pointer to member data TYPE.
+   TI provides information about the particular type_info derivation,
+   which adds class, target type and qualifier flags members to the type_info
+   base.  */
+
+static tree
+ptm_initializer (tinfo_s *ti, tree target)
+{
+  tree init = tinfo_base_init (ti, target);
+  tree to = TYPE_PTRMEM_POINTED_TO_TYPE (target);
+  tree klass = TYPE_PTRMEM_CLASS_TYPE (target);
+  int flags = qualifier_flags (to);
+  bool incomplete = target_incomplete_p (to);
+  vec<constructor_elt, va_gc> *v;
+  vec_alloc (v, 4);
+
+  if (incomplete)
+    flags |= 0x8;
+  if (!COMPLETE_TYPE_P (klass))
+    flags |= 0x10;
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init);
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, build_int_cst (NULL_TREE, flags));
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
+                          get_tinfo_ptr (TYPE_MAIN_VARIANT (to)));
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, get_tinfo_ptr (klass));
+
+  init = build_constructor (init_list_type_node, v);
+  TREE_CONSTANT (init) = 1;
+  TREE_STATIC (init) = 1;
+  return init;
+}
+
+/* Return the CONSTRUCTOR expr for a type_info of class TYPE.
+   TI provides information about the particular __class_type_info derivation,
+   which adds hint flags and N extra initializers to the type_info base.  */
+
+static tree
+class_initializer (tinfo_s *ti, tree target, unsigned n, ...)
+{
+  tree init = tinfo_base_init (ti, target);
+  va_list extra_inits;
+  unsigned i;
+  vec<constructor_elt, va_gc> *v;
+  vec_alloc (v, n+1);
+
+  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init);
+  va_start (extra_inits, n);
+  for (i = 0; i < n; i++)
+    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, va_arg (extra_inits, tree));
+  va_end (extra_inits);
+
+  init = build_constructor (init_list_type_node, v);
+  TREE_CONSTANT (init) = 1;
+  TREE_STATIC (init) = 1;
+  return init;
+}
+
+/* Returns true if the typeinfo for type should be placed in
+   the runtime library.  */
+
+static bool
+typeinfo_in_lib_p (tree type)
+{
+  /* The typeinfo objects for `T*' and `const T*' are in the runtime
+     library for simple types T.  */
+  if (TYPE_PTR_P (type)
+      && (cp_type_quals (TREE_TYPE (type)) == TYPE_QUAL_CONST
+	  || cp_type_quals (TREE_TYPE (type)) == TYPE_UNQUALIFIED))
+    type = TREE_TYPE (type);
+
+  switch (TREE_CODE (type))
+    {
+    case INTEGER_TYPE:
+    case BOOLEAN_TYPE:
+    case REAL_TYPE:
+    case VOID_TYPE:
+    case NULLPTR_TYPE:
+      return true;
+
+    case LANG_TYPE:
+      /* fall through.  */
+
+    default:
+      return false;
+    }
+}
+
+/* Generate the initializer for the type info describing TYPE.  TK_INDEX is
+   the index of the descriptor in the tinfo_desc vector. */
+
+static tree
+get_pseudo_ti_init (tree type, unsigned tk_index)
+{
+  tinfo_s *ti = get_tinfo_desc (tk_index);
+
+  gcc_assert (at_eof);
+  switch (tk_index)
+    {
+    case TK_POINTER_MEMBER_TYPE:
+      return ptm_initializer (ti, type);
+
+    case TK_POINTER_TYPE:
+      return ptr_initializer (ti, type);
+
+    case TK_BUILTIN_TYPE:
+    case TK_ENUMERAL_TYPE:
+    case TK_FUNCTION_TYPE:
+    case TK_ARRAY_TYPE:
+      return generic_initializer (ti, type);
+
+    case TK_CLASS_TYPE:
+      return class_initializer (ti, type, 0);
+
+    case TK_SI_CLASS_TYPE:
+      {
+	tree base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (type), 0);
+	tree tinfo = get_tinfo_ptr (BINFO_TYPE (base_binfo));
+
+	/* get_tinfo_ptr might have reallocated the tinfo_descs vector.  */
+	ti = &(*tinfo_descs)[tk_index];
+	return class_initializer (ti, type, 1, tinfo);
+      }
+
+    default:
+      {
+	int hint = ((CLASSTYPE_REPEATED_BASE_P (type) << 0)
+		    | (CLASSTYPE_DIAMOND_SHAPED_P (type) << 1));
+	tree binfo = TYPE_BINFO (type);
+	unsigned nbases = BINFO_N_BASE_BINFOS (binfo);
+	vec<tree, va_gc> *base_accesses = BINFO_BASE_ACCESSES (binfo);
+	tree offset_type = LONGPTR_T;
+	vec<constructor_elt, va_gc> *init_vec = NULL;
+
+	gcc_assert (tk_index - TK_VMI_CLASS_TYPES + 1 == nbases);
+
+	vec_safe_grow (init_vec, nbases);
+	/* Generate the base information initializer.  */
+	for (unsigned ix = nbases; ix--;)
+	  {
+	    tree base_binfo = BINFO_BASE_BINFO (binfo, ix);
+	    int flags = 0;
+	    tree tinfo;
+	    tree offset;
+	    vec<constructor_elt, va_gc> *v;
+
+	    if ((*base_accesses)[ix] == access_public_node)
+	      flags |= 2;
+	    tinfo = get_tinfo_ptr (BINFO_TYPE (base_binfo));
+	    if (BINFO_VIRTUAL_P (base_binfo))
+	      {
+		/* We store the vtable offset at which the virtual
+		   base offset can be found.  */
+		offset = BINFO_VPTR_FIELD (base_binfo);
+		flags |= 1;
+	      }
+	    else
+	      offset = BINFO_OFFSET (base_binfo);
+
+	    /* Combine offset and flags into one field.  */
+	    offset = fold_convert (offset_type, offset);
+	    offset = fold_build2_loc (input_location,
+				  LSHIFT_EXPR, offset_type, offset,
+				  build_int_cst (offset_type, 8));
+	    offset = fold_build2_loc (input_location,
+				  BIT_IOR_EXPR, offset_type, offset,
+				  build_int_cst (offset_type, flags));
+	    vec_alloc (v, 2);
+	    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, tinfo);
+	    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, offset);
+	    tree base_init = build_constructor (init_list_type_node, v);
+	    constructor_elt *e = &(*init_vec)[ix];
+	    e->index = NULL_TREE;
+	    e->value = base_init;
+	  }
+	tree base_inits = build_constructor (init_list_type_node, init_vec);
+
+	/* get_tinfo_ptr might have reallocated the tinfo_descs vector.  */
+	ti = &(*tinfo_descs)[tk_index];
+	return class_initializer (ti, type, 3,
+				  build_int_cst (NULL_TREE, hint),
+				  build_int_cst (NULL_TREE, nbases),
+				  base_inits);
+      }
+    }
+}
+
+/* Return the index of a pseudo type info type node used to describe
+   TYPE.  TYPE must be a complete type (or cv void), except at the end
+   of the translation unit.  */
+
+static unsigned
+get_pseudo_ti_index (tree type)
+{
+  unsigned ix;
+
+  switch (TREE_CODE (type))
+    {
+    case OFFSET_TYPE:
+      ix = TK_POINTER_MEMBER_TYPE;
+      break;
+
+    case POINTER_TYPE:
+      ix = TK_POINTER_TYPE;
+      break;
+
+    case ENUMERAL_TYPE:
+      ix = TK_ENUMERAL_TYPE;
+      break;
+
+    case FUNCTION_TYPE:
+      ix = TK_FUNCTION_TYPE;
+      break;
+
+    case ARRAY_TYPE:
+      ix = TK_ARRAY_TYPE;
+      break;
+
+    case UNION_TYPE:
+    case RECORD_TYPE:
+      if (TYPE_PTRMEMFUNC_P (type))
+	ix = TK_POINTER_MEMBER_TYPE;
+      else if (!COMPLETE_TYPE_P (type))
+	{
+	  if (!at_eof)
+	    cxx_incomplete_type_error (NULL_TREE, type);
+	  ix = TK_CLASS_TYPE;
+	}
+      else if (!TYPE_BINFO (type)
+	       || !BINFO_N_BASE_BINFOS (TYPE_BINFO (type)))
+	ix = TK_CLASS_TYPE;
+      else
+	{
+	  tree binfo = TYPE_BINFO (type);
+	  vec<tree, va_gc> *base_accesses = BINFO_BASE_ACCESSES (binfo);
+	  tree base_binfo = BINFO_BASE_BINFO (binfo, 0);
+	  int num_bases = BINFO_N_BASE_BINFOS (binfo);
+
+	  if (num_bases == 1
+	      && (*base_accesses)[0] == access_public_node
+	      && !BINFO_VIRTUAL_P (base_binfo)
+	      && integer_zerop (BINFO_OFFSET (base_binfo)))
+	    /* single non-virtual public.  */
+	    ix = TK_SI_CLASS_TYPE;
+	  else
+	    ix = TK_VMI_CLASS_TYPES + num_bases - 1;
+	}
+      break;
+
+    default:
+      ix = TK_BUILTIN_TYPE;
+      break;
+    }
+  return ix;
+}
+
+/* Return pointer to tinfo descriptor.  Possibly creating the tinfo
+   descriptor in the first place.  */
+
+static tinfo_s *
+get_tinfo_desc (unsigned ix)
+{
+  unsigned len = tinfo_descs->length ();
+
+  if (len <= ix)
+    {
+      /* too short, extend.  */
+      len = ix + 1 - len;
+      vec_safe_reserve (tinfo_descs, len);
+      tinfo_s elt;
+      elt.type = elt.vtable = elt.name = NULL_TREE;
+      while (len--)
+	tinfo_descs->quick_push (elt);
+    }
+
+  tinfo_s *res = &(*tinfo_descs)[ix];
+
+  if (res->type)
+    return res;
+
+  /* Ok, we have to create it.  This layout must be consistent with
+     that defined in the runtime support.  We explicitly manage the
+     vtable member, and name it for real type as used in the runtime.
+     The RECORD type has a different name, to avoid collisions.  We
+     have to delay generating the VAR_DECL of the vtable until the end
+     of the translation, when we'll have seen the library definition,
+     if there was one.  */
+
+  /* Fields to add, chained in reverse order.  */
+  tree fields = NULL_TREE;
+
+  if (ix >= TK_DERIVED_TYPES)
+    {
+      /* First field is the pseudo type_info base class.  */
+      tree fld_base = build_decl (BUILTINS_LOCATION, FIELD_DECL, NULL_TREE,
+				  get_tinfo_desc (TK_TYPE_INFO_TYPE)->type);
+
+      DECL_CHAIN (fld_base) = fields;
+      fields = fld_base;
+    }
+
+  switch (ix)
+    {
+    case TK_TYPE_INFO_TYPE:
+      {
+	tree fld_ptr = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, const_ptr_type_node);
+	fields = fld_ptr;
+
+	tree fld_str = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, const_string_type_node);
+	DECL_CHAIN (fld_str) = fields;
+	fields = fld_str;
+	break;
+      }
+
+    case TK_BASE_TYPE:
+      {
+	/* Base class internal helper. Pointer to base type, offset to
+	   base, flags.  */
+	tree fld_ptr = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, type_info_ptr_type);
+	DECL_CHAIN (fld_ptr) = fields;
+	fields = fld_ptr;
+
+	tree fld_flag = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				    NULL_TREE, LONGPTR_T);
+	DECL_CHAIN (fld_flag) = fields;
+	fields = fld_flag;
+	break;
+      }
+
+    case TK_BUILTIN_TYPE:
+      /* Fundamental type_info */
+      break;
+
+    case TK_ARRAY_TYPE:
+      break;
+
+    case TK_FUNCTION_TYPE:
+      break;
+
+    case TK_ENUMERAL_TYPE:
+      break;
+
+    case TK_POINTER_TYPE:
+    case TK_POINTER_MEMBER_TYPE:
+      {
+	/* Pointer type_info. Adds two fields, qualification mask and
+	   pointer to the pointed to type.  This is really a
+	   descendant of __pbase_type_info.  */
+	tree fld_mask = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				    NULL_TREE, integer_type_node);
+	DECL_CHAIN (fld_mask) = fields;
+	fields = fld_mask;
+
+	tree fld_ptr = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, type_info_ptr_type);
+	DECL_CHAIN (fld_ptr) = fields;
+	fields = fld_ptr;
+
+	if (ix == TK_POINTER_MEMBER_TYPE)
+	  {
+	    /* Add a pointer to the class too.  */
+	    tree fld_cls = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, type_info_ptr_type);
+	    DECL_CHAIN (fld_cls) = fields;
+	    fields = fld_cls;
+	  }
+	break;
+      }
+
+    case TK_CLASS_TYPE:
+      /* Class type_info.  No additional fields.  */
+      break;
+
+    case TK_SI_CLASS_TYPE:
+      {
+	/* Single public non-virtual base class. Add pointer to base
+	   class.  This is really a descendant of
+	   __class_type_info.  */
+	tree fld_ptr = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, type_info_ptr_type);
+	DECL_CHAIN (fld_ptr) = fields;
+	fields = fld_ptr;
+	break;
+      }
+
+    default: /* Multiple inheritance.  */
+      {
+	unsigned num_bases = ix - TK_VMI_CLASS_TYPES + 1;
+
+	tree fld_flg = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, integer_type_node);
+	DECL_CHAIN (fld_flg) = fields;
+	fields = fld_flg;
+	
+	tree fld_cnt = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, integer_type_node);
+	DECL_CHAIN (fld_cnt) = fields;
+	fields = fld_cnt;
+
+	/* Create the array of __base_class_type_info entries.  */
+	tree domain = build_index_type (size_int (num_bases - 1));
+	tree array = build_array_type (get_tinfo_desc (TK_BASE_TYPE)->type,
+				       domain);
+	tree fld_ary = build_decl (BUILTINS_LOCATION, FIELD_DECL,
+				   NULL_TREE, array);
+	DECL_CHAIN (fld_ary) = fields;
+	fields = fld_ary;
+	break;
+      }
+    }
+
+  push_abi_namespace ();
+
+  /* Generate the pseudo type name.  */
+  const char *real_name = tinfo_names[ix < TK_VMI_CLASS_TYPES
+				      ? ix : unsigned (TK_VMI_CLASS_TYPES)];
+  size_t name_len = strlen (real_name);
+  char *pseudo_name = (char *) alloca (name_len + 30);
+  memcpy (pseudo_name, real_name, name_len);
+  /* Those >= TK_VMI_CLASS_TYPES need a discriminator, may as well
+     apply it to all.  See get_peudo_tinfo_index where we make use of
+     this.  */
+  sprintf (pseudo_name + name_len, "_pseudo_%d", ix);
+
+  /* Create the pseudo type.  */
+  tree pseudo_type = make_class_type (RECORD_TYPE);
+  /* Pass the fields chained in reverse.  */
+  finish_builtin_struct (pseudo_type, pseudo_name, fields, NULL_TREE);
+  CLASSTYPE_AS_BASE (pseudo_type) = pseudo_type;
+
+  res->type = cp_build_qualified_type (pseudo_type, TYPE_QUAL_CONST);
+  res->name = get_identifier (real_name);
+
+  /* Pretend this is public so determine_visibility doesn't give vtables
+     internal linkage.  */
+  TREE_PUBLIC (TYPE_MAIN_DECL (res->type)) = 1;
+
+  pop_abi_namespace ();
+  return res;
+}
+
+/* We lazily create the type info types.  */
+
+static void
+create_tinfo_types (void)
+{
+  gcc_assert (!tinfo_descs);
+
+  vec_alloc (tinfo_descs, TK_MAX + 20);
+}
+
+/* Helper for emit_support_tinfos. Emits the type_info descriptor of
+   a single type.  */
+
+void
+emit_support_tinfo_1 (tree bltn)
+{
+  tree types[3];
+
+  if (bltn == NULL_TREE)
+    return;
+  types[0] = bltn;
+  types[1] = build_pointer_type (bltn);
+  types[2] = build_pointer_type (cp_build_qualified_type (bltn,
+							  TYPE_QUAL_CONST));
+
+  for (int i = 0; i < 3; ++i)
+    {
+      tree tinfo = get_tinfo_decl (types[i]);
+      TREE_USED (tinfo) = 1;
+      mark_needed (tinfo);
+      /* The C++ ABI requires that these objects be COMDAT.  But,
+	 On systems without weak symbols, initialized COMDAT
+	 objects are emitted with internal linkage.  (See
+	 comdat_linkage for details.)  Since we want these objects
+	 to have external linkage so that copies do not have to be
+	 emitted in code outside the runtime library, we make them
+	 non-COMDAT here.  
+
+	 It might also not be necessary to follow this detail of the
+	 ABI.  */
+      if (!flag_weak || ! targetm.cxx.library_rtti_comdat ())
+	{
+	  gcc_assert (TREE_PUBLIC (tinfo) && !DECL_COMDAT (tinfo));
+	  DECL_INTERFACE_KNOWN (tinfo) = 1;
+	}
+    }
+}
+
+/* Emit the type_info descriptors which are guaranteed to be in the runtime
+   support.  Generating them here guarantees consistency with the other
+   structures.  We use the following heuristic to determine when the runtime
+   is being generated.  If std::__fundamental_type_info is defined, and its
+   destructor is defined, then the runtime is being built.  */
+
+void
+emit_support_tinfos (void)
+{
+  /* Dummy static variable so we can put nullptr in the array; it will be
+     set before we actually start to walk the array.  */
+  static tree *const fundamentals[] =
+  {
+    &void_type_node,
+    &boolean_type_node,
+    &wchar_type_node, &char16_type_node, &char32_type_node,
+    &char_type_node, &signed_char_type_node, &unsigned_char_type_node,
+    &short_integer_type_node, &short_unsigned_type_node,
+    &integer_type_node, &unsigned_type_node,
+    &long_integer_type_node, &long_unsigned_type_node,
+    &long_long_integer_type_node, &long_long_unsigned_type_node,
+    &float_type_node, &double_type_node, &long_double_type_node,
+    &dfloat32_type_node, &dfloat64_type_node, &dfloat128_type_node,
+    &nullptr_type_node,
+    0
+  };
+  int ix;
+
+  /* Look for a defined class.  */
+  tree bltn_type = lookup_qualified_name
+    (abi_node, get_identifier ("__fundamental_type_info"), true, false, false);
+  if (TREE_CODE (bltn_type) != TYPE_DECL)
+    return;
+
+  bltn_type = TREE_TYPE (bltn_type);
+  if (!COMPLETE_TYPE_P (bltn_type))
+    return;
+  tree dtor = CLASSTYPE_DESTRUCTOR (bltn_type);
+  if (!dtor || DECL_EXTERNAL (dtor))
+    return;
+
+  /* All these are really builtins.  So set the location.  */
+  location_t saved_loc = input_location;
+  input_location = BUILTINS_LOCATION;
+  doing_runtime = 1;
+  for (ix = 0; fundamentals[ix]; ix++)
+    emit_support_tinfo_1 (*fundamentals[ix]);
+  for (ix = 0; ix < NUM_INT_N_ENTS; ix ++)
+    if (int_n_enabled_p[ix])
+      {
+	emit_support_tinfo_1 (int_n_trees[ix].signed_type);
+	emit_support_tinfo_1 (int_n_trees[ix].unsigned_type);
+      }
+  for (tree t = registered_builtin_types; t; t = TREE_CHAIN (t))
+    emit_support_tinfo_1 (TREE_VALUE (t));
+  input_location = saved_loc;
+}
+
+/* Finish a type info decl. DECL_PTR is a pointer to an unemitted
+   tinfo decl.  Determine whether it needs emitting, and if so
+   generate the initializer.  */
+
+bool
+emit_tinfo_decl (tree decl)
+{
+  tree type = TREE_TYPE (DECL_NAME (decl));
+  int in_library = typeinfo_in_lib_p (type);
+
+  gcc_assert (DECL_TINFO_P (decl));
+
+  if (in_library)
+    {
+      if (doing_runtime)
+	DECL_EXTERNAL (decl) = 0;
+      else
+	{
+	  /* If we're not in the runtime, then DECL (which is already
+	     DECL_EXTERNAL) will not be defined here.  */
+	  DECL_INTERFACE_KNOWN (decl) = 1;
+	  return false;
+	}
+    }
+  else if (involves_incomplete_p (type))
+    {
+      if (!decl_needed_p (decl))
+	return false;
+      /* If TYPE involves an incomplete class type, then the typeinfo
+	 object will be emitted with internal linkage.  There is no
+	 way to know whether or not types are incomplete until the end
+	 of the compilation, so this determination must be deferred
+	 until this point.  */
+      TREE_PUBLIC (decl) = 0;
+      DECL_EXTERNAL (decl) = 0;
+      DECL_INTERFACE_KNOWN (decl) = 1;
+    }
+
+  import_export_decl (decl);
+  if (DECL_NOT_REALLY_EXTERN (decl) && decl_needed_p (decl))
+    {
+      tree init;
+
+      DECL_EXTERNAL (decl) = 0;
+      init = get_pseudo_ti_init (type, get_pseudo_ti_index (type));
+      DECL_INITIAL (decl) = init;
+      mark_used (decl);
+      cp_finish_decl (decl, init, false, NULL_TREE, 0);
+      /* Avoid targets optionally bumping up the alignment to improve
+	 vector instruction accesses, tinfo are never accessed this way.  */
+#ifdef DATA_ABI_ALIGNMENT
+      SET_DECL_ALIGN (decl, DATA_ABI_ALIGNMENT (decl, TYPE_ALIGN (TREE_TYPE (decl))));
+      DECL_USER_ALIGN (decl) = true;
+#endif
+      return true;
+    }
+  else
+    return false;
+}
+
+#include "gt-cp-rtti.h"