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// Methods for type_info for -*- C++ -*- Run Time Type Identification.
// Copyright (C) 1994, 1996 Free Software Foundation
// This file is part of GNU CC.
// GNU CC 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 2, or (at your option)
// any later version.
// GNU CC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with GNU CC; see the file COPYING. If not, write to
// the Free Software Foundation, 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.
// As a special exception, if you link this library with other files,
// some of which are compiled with GCC, to produce an executable,
// this library does not by itself cause the resulting executable
// to be covered by the GNU General Public License.
// This exception does not however invalidate any other reasons why
// the executable file might be covered by the GNU General Public License.
#include <stddef.h>
#include "tinfo.h"
#include "new" // for placement new
// This file contains the minimal working set necessary to link with code
// that uses virtual functions and -frtti but does not actually use RTTI
// functionality.
~type_info ()
{ }
extern "C" void
__rtti_class (void *addr, const char *name,
const __class_type_info::base_info *bl, size_t bn)
{ new (addr) __class_type_info (name, bl, bn); }
extern "C" void
__rtti_si (void *addr, const char *n, const std::type_info *ti)
new (addr) __si_type_info
(n, static_cast <const __user_type_info &> (*ti));
extern "C" void
__rtti_user (void *addr, const char *name)
{ new (addr) __user_type_info (name); }
// dynamic_cast helper methods.
// Returns a pointer to the desired sub-object or 0.
void * __user_type_info::
dcast (const type_info& to, int, void *addr, const type_info *, void *) const
{ return (*this == to) ? addr : 0; }
void * __si_type_info::
dcast (const type_info& to, int require_public, void *addr,
const type_info *sub, void *subptr) const
if (*this == to)
return addr;
return base.dcast (to, require_public, addr, sub, subptr);
void* __class_type_info::
dcast (const type_info& desired, int is_public, void *objptr,
const type_info *sub, void *subptr) const
if (*this == desired)
return objptr;
void *match_found = 0;
for (size_t i = 0; i < n_bases; i++)
if (is_public && base_list[i].access != PUBLIC)
void *p = (char *)objptr + base_list[i].offset;
if (base_list[i].is_virtual)
p = *(void **)p;
p = base_list[i].base->dcast (desired, is_public, p, sub, subptr);
if (p)
if (match_found == 0)
match_found = p;
else if (match_found != p)
if (sub)
// Perhaps we're downcasting from *sub to desired; see if
// subptr is a subobject of exactly one of {match_found,p}.
const __user_type_info &d =
static_cast <const __user_type_info &> (desired);
void *os = d.dcast (*sub, 1, match_found);
void *ns = d.dcast (*sub, 1, p);
if (os == ns)
/* ambiguous -- subptr is a virtual base */;
else if (os == subptr)
else if (ns == subptr)
match_found = p;
// base found at two different pointers,
// conversion is not unique
return 0;
return match_found;