722 lines
25 KiB
C++
722 lines
25 KiB
C++
// Methods for type_info for -*- C++ -*- Run Time Type Identification.
|
|
// Copyright (C) 1994, 1996, 1998, 1999, 2000, 2001, 2002
|
|
// 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
|
|
// 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 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, you may use this file as part of a free software
|
|
// library without restriction. Specifically, if other files instantiate
|
|
// templates or use macros or inline functions from this file, or you compile
|
|
// this file and link it with other files to produce an executable, this
|
|
// file 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 <cstddef>
|
|
#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.
|
|
|
|
std::type_info::
|
|
~type_info ()
|
|
{ }
|
|
|
|
std::bad_cast::~bad_cast() throw() { }
|
|
std::bad_typeid::~bad_typeid() throw() { }
|
|
|
|
#if !__GXX_MERGED_TYPEINFO_NAMES
|
|
|
|
// We can't rely on common symbols being shared between shared objects.
|
|
bool std::type_info::
|
|
operator== (const std::type_info& arg) const
|
|
{
|
|
return (&arg == this) || (__builtin_strcmp (name (), arg.name ()) == 0);
|
|
}
|
|
|
|
#endif
|
|
|
|
namespace std {
|
|
|
|
// return true if this is a type_info for a pointer type
|
|
bool type_info::
|
|
__is_pointer_p () const
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// return true if this is a type_info for a function type
|
|
bool type_info::
|
|
__is_function_p () const
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// try and catch a thrown object.
|
|
bool type_info::
|
|
__do_catch (const type_info *thr_type, void **, unsigned) const
|
|
{
|
|
return *this == *thr_type;
|
|
}
|
|
|
|
// upcast from this type to the target. __class_type_info will override
|
|
bool type_info::
|
|
__do_upcast (const abi::__class_type_info *, void **) const
|
|
{
|
|
return false;
|
|
}
|
|
|
|
};
|
|
|
|
namespace {
|
|
|
|
using namespace std;
|
|
using namespace abi;
|
|
|
|
// initial part of a vtable, this structure is used with offsetof, so we don't
|
|
// have to keep alignments consistent manually.
|
|
struct vtable_prefix {
|
|
ptrdiff_t whole_object; // offset to most derived object
|
|
const __class_type_info *whole_type; // pointer to most derived type_info
|
|
const void *origin; // what a class's vptr points to
|
|
};
|
|
|
|
template <typename T>
|
|
inline const T *
|
|
adjust_pointer (const void *base, ptrdiff_t offset)
|
|
{
|
|
return reinterpret_cast <const T *>
|
|
(reinterpret_cast <const char *> (base) + offset);
|
|
}
|
|
|
|
// ADDR is a pointer to an object. Convert it to a pointer to a base,
|
|
// using OFFSET. IS_VIRTUAL is true, if we are getting a virtual base.
|
|
inline void const *
|
|
convert_to_base (void const *addr, bool is_virtual, ptrdiff_t offset)
|
|
{
|
|
if (is_virtual)
|
|
{
|
|
const void *vtable = *static_cast <const void *const *> (addr);
|
|
|
|
offset = *adjust_pointer<ptrdiff_t> (vtable, offset);
|
|
}
|
|
|
|
return adjust_pointer<void> (addr, offset);
|
|
}
|
|
|
|
// some predicate functions for __class_type_info::__sub_kind
|
|
inline bool contained_p (__class_type_info::__sub_kind access_path)
|
|
{
|
|
return access_path >= __class_type_info::__contained_mask;
|
|
}
|
|
inline bool public_p (__class_type_info::__sub_kind access_path)
|
|
{
|
|
return access_path & __class_type_info::__contained_public_mask;
|
|
}
|
|
inline bool virtual_p (__class_type_info::__sub_kind access_path)
|
|
{
|
|
return (access_path & __class_type_info::__contained_virtual_mask);
|
|
}
|
|
inline bool contained_public_p (__class_type_info::__sub_kind access_path)
|
|
{
|
|
return ((access_path & __class_type_info::__contained_public)
|
|
== __class_type_info::__contained_public);
|
|
}
|
|
inline bool contained_nonpublic_p (__class_type_info::__sub_kind access_path)
|
|
{
|
|
return ((access_path & __class_type_info::__contained_public)
|
|
== __class_type_info::__contained_mask);
|
|
}
|
|
inline bool contained_nonvirtual_p (__class_type_info::__sub_kind access_path)
|
|
{
|
|
return ((access_path & (__class_type_info::__contained_mask
|
|
| __class_type_info::__contained_virtual_mask))
|
|
== __class_type_info::__contained_mask);
|
|
}
|
|
|
|
static const __class_type_info *const nonvirtual_base_type =
|
|
static_cast <const __class_type_info *> (0) + 1;
|
|
|
|
}; // namespace
|
|
|
|
namespace __cxxabiv1
|
|
{
|
|
|
|
__class_type_info::
|
|
~__class_type_info ()
|
|
{}
|
|
|
|
__si_class_type_info::
|
|
~__si_class_type_info ()
|
|
{}
|
|
|
|
__vmi_class_type_info::
|
|
~__vmi_class_type_info ()
|
|
{}
|
|
|
|
// __upcast_result is used to hold information during traversal of a class
|
|
// hierarchy when catch matching.
|
|
struct __class_type_info::__upcast_result
|
|
{
|
|
const void *dst_ptr; // pointer to caught object
|
|
__sub_kind part2dst; // path from current base to target
|
|
int src_details; // hints about the source type hierarchy
|
|
const __class_type_info *base_type; // where we found the target,
|
|
// if in vbase the __class_type_info of vbase
|
|
// if a non-virtual base then 1
|
|
// else NULL
|
|
public:
|
|
__upcast_result (int d)
|
|
:dst_ptr (NULL), part2dst (__unknown), src_details (d), base_type (NULL)
|
|
{}
|
|
};
|
|
|
|
// __dyncast_result is used to hold information during traversal of a class
|
|
// hierarchy when dynamic casting.
|
|
struct __class_type_info::__dyncast_result
|
|
{
|
|
const void *dst_ptr; // pointer to target object or NULL
|
|
__sub_kind whole2dst; // path from most derived object to target
|
|
__sub_kind whole2src; // path from most derived object to sub object
|
|
__sub_kind dst2src; // path from target to sub object
|
|
int whole_details; // details of the whole class hierarchy
|
|
|
|
public:
|
|
__dyncast_result (int details_ = __vmi_class_type_info::__flags_unknown_mask)
|
|
:dst_ptr (NULL), whole2dst (__unknown),
|
|
whole2src (__unknown), dst2src (__unknown),
|
|
whole_details (details_)
|
|
{}
|
|
};
|
|
|
|
bool __class_type_info::
|
|
__do_catch (const type_info *thr_type,
|
|
void **thr_obj,
|
|
unsigned outer) const
|
|
{
|
|
if (*this == *thr_type)
|
|
return true;
|
|
if (outer >= 4)
|
|
// Neither `A' nor `A *'.
|
|
return false;
|
|
return thr_type->__do_upcast (this, thr_obj);
|
|
}
|
|
|
|
bool __class_type_info::
|
|
__do_upcast (const __class_type_info *dst_type,
|
|
void **obj_ptr) const
|
|
{
|
|
__upcast_result result (__vmi_class_type_info::__flags_unknown_mask);
|
|
|
|
__do_upcast (dst_type, *obj_ptr, result);
|
|
if (!contained_public_p (result.part2dst))
|
|
return false;
|
|
*obj_ptr = const_cast <void *> (result.dst_ptr);
|
|
return true;
|
|
}
|
|
|
|
inline __class_type_info::__sub_kind __class_type_info::
|
|
__find_public_src (ptrdiff_t src2dst,
|
|
const void *obj_ptr,
|
|
const __class_type_info *src_type,
|
|
const void *src_ptr) const
|
|
{
|
|
if (src2dst >= 0)
|
|
return adjust_pointer <void> (obj_ptr, src2dst) == src_ptr
|
|
? __contained_public : __not_contained;
|
|
if (src2dst == -2)
|
|
return __not_contained;
|
|
return __do_find_public_src (src2dst, obj_ptr, src_type, src_ptr);
|
|
}
|
|
|
|
__class_type_info::__sub_kind __class_type_info::
|
|
__do_find_public_src (ptrdiff_t,
|
|
const void *obj_ptr,
|
|
const __class_type_info *,
|
|
const void *src_ptr) const
|
|
{
|
|
if (src_ptr == obj_ptr)
|
|
// Must be our type, as the pointers match.
|
|
return __contained_public;
|
|
return __not_contained;
|
|
}
|
|
|
|
__class_type_info::__sub_kind __si_class_type_info::
|
|
__do_find_public_src (ptrdiff_t src2dst,
|
|
const void *obj_ptr,
|
|
const __class_type_info *src_type,
|
|
const void *src_ptr) const
|
|
{
|
|
if (src_ptr == obj_ptr && *this == *src_type)
|
|
return __contained_public;
|
|
return __base_type->__do_find_public_src (src2dst, obj_ptr, src_type, src_ptr);
|
|
}
|
|
|
|
__class_type_info::__sub_kind __vmi_class_type_info::
|
|
__do_find_public_src (ptrdiff_t src2dst,
|
|
const void *obj_ptr,
|
|
const __class_type_info *src_type,
|
|
const void *src_ptr) const
|
|
{
|
|
if (obj_ptr == src_ptr && *this == *src_type)
|
|
return __contained_public;
|
|
|
|
for (std::size_t i = __base_count; i--;)
|
|
{
|
|
if (!__base_info[i].__is_public_p ())
|
|
continue; // Not public, can't be here.
|
|
|
|
const void *base = obj_ptr;
|
|
ptrdiff_t offset = __base_info[i].__offset ();
|
|
bool is_virtual = __base_info[i].__is_virtual_p ();
|
|
|
|
if (is_virtual)
|
|
{
|
|
if (src2dst == -3)
|
|
continue; // Not a virtual base, so can't be here.
|
|
}
|
|
base = convert_to_base (base, is_virtual, offset);
|
|
|
|
__sub_kind base_kind = __base_info[i].__base_type->__do_find_public_src
|
|
(src2dst, base, src_type, src_ptr);
|
|
if (contained_p (base_kind))
|
|
{
|
|
if (is_virtual)
|
|
base_kind = __sub_kind (base_kind | __contained_virtual_mask);
|
|
return base_kind;
|
|
}
|
|
}
|
|
|
|
return __not_contained;
|
|
}
|
|
|
|
bool __class_type_info::
|
|
__do_dyncast (ptrdiff_t,
|
|
__sub_kind access_path,
|
|
const __class_type_info *dst_type,
|
|
const void *obj_ptr,
|
|
const __class_type_info *src_type,
|
|
const void *src_ptr,
|
|
__dyncast_result &__restrict result) const
|
|
{
|
|
if (obj_ptr == src_ptr && *this == *src_type)
|
|
{
|
|
// The src object we started from. Indicate how we are accessible from
|
|
// the most derived object.
|
|
result.whole2src = access_path;
|
|
return false;
|
|
}
|
|
if (*this == *dst_type)
|
|
{
|
|
result.dst_ptr = obj_ptr;
|
|
result.whole2dst = access_path;
|
|
result.dst2src = __not_contained;
|
|
return false;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool __si_class_type_info::
|
|
__do_dyncast (ptrdiff_t src2dst,
|
|
__sub_kind access_path,
|
|
const __class_type_info *dst_type,
|
|
const void *obj_ptr,
|
|
const __class_type_info *src_type,
|
|
const void *src_ptr,
|
|
__dyncast_result &__restrict result) const
|
|
{
|
|
if (*this == *dst_type)
|
|
{
|
|
result.dst_ptr = obj_ptr;
|
|
result.whole2dst = access_path;
|
|
if (src2dst >= 0)
|
|
result.dst2src = adjust_pointer <void> (obj_ptr, src2dst) == src_ptr
|
|
? __contained_public : __not_contained;
|
|
else if (src2dst == -2)
|
|
result.dst2src = __not_contained;
|
|
return false;
|
|
}
|
|
if (obj_ptr == src_ptr && *this == *src_type)
|
|
{
|
|
// The src object we started from. Indicate how we are accessible from
|
|
// the most derived object.
|
|
result.whole2src = access_path;
|
|
return false;
|
|
}
|
|
return __base_type->__do_dyncast (src2dst, access_path, dst_type, obj_ptr,
|
|
src_type, src_ptr, result);
|
|
}
|
|
|
|
// This is a big hairy function. Although the run-time behaviour of
|
|
// dynamic_cast is simple to describe, it gives rise to some non-obvious
|
|
// behaviour. We also desire to determine as early as possible any definite
|
|
// answer we can get. Because it is unknown what the run-time ratio of
|
|
// succeeding to failing dynamic casts is, we do not know in which direction
|
|
// to bias any optimizations. To that end we make no particular effort towards
|
|
// early fail answers or early success answers. Instead we try to minimize
|
|
// work by filling in things lazily (when we know we need the information),
|
|
// and opportunisticly take early success or failure results.
|
|
bool __vmi_class_type_info::
|
|
__do_dyncast (ptrdiff_t src2dst,
|
|
__sub_kind access_path,
|
|
const __class_type_info *dst_type,
|
|
const void *obj_ptr,
|
|
const __class_type_info *src_type,
|
|
const void *src_ptr,
|
|
__dyncast_result &__restrict result) const
|
|
{
|
|
if (result.whole_details & __flags_unknown_mask)
|
|
result.whole_details = __flags;
|
|
|
|
if (obj_ptr == src_ptr && *this == *src_type)
|
|
{
|
|
// The src object we started from. Indicate how we are accessible from
|
|
// the most derived object.
|
|
result.whole2src = access_path;
|
|
return false;
|
|
}
|
|
if (*this == *dst_type)
|
|
{
|
|
result.dst_ptr = obj_ptr;
|
|
result.whole2dst = access_path;
|
|
if (src2dst >= 0)
|
|
result.dst2src = adjust_pointer <void> (obj_ptr, src2dst) == src_ptr
|
|
? __contained_public : __not_contained;
|
|
else if (src2dst == -2)
|
|
result.dst2src = __not_contained;
|
|
return false;
|
|
}
|
|
|
|
bool result_ambig = false;
|
|
for (std::size_t i = __base_count; i--;)
|
|
{
|
|
__dyncast_result result2 (result.whole_details);
|
|
void const *base = obj_ptr;
|
|
__sub_kind base_access = access_path;
|
|
ptrdiff_t offset = __base_info[i].__offset ();
|
|
bool is_virtual = __base_info[i].__is_virtual_p ();
|
|
|
|
if (is_virtual)
|
|
base_access = __sub_kind (base_access | __contained_virtual_mask);
|
|
base = convert_to_base (base, is_virtual, offset);
|
|
|
|
if (!__base_info[i].__is_public_p ())
|
|
{
|
|
if (src2dst == -2 &&
|
|
!(result.whole_details
|
|
& (__non_diamond_repeat_mask | __diamond_shaped_mask)))
|
|
// The hierarchy has no duplicate bases (which might ambiguate
|
|
// things) and where we started is not a public base of what we
|
|
// want (so it cannot be a downcast). There is nothing of interest
|
|
// hiding in a non-public base.
|
|
continue;
|
|
base_access = __sub_kind (base_access & ~__contained_public_mask);
|
|
}
|
|
|
|
bool result2_ambig
|
|
= __base_info[i].__base_type->__do_dyncast (src2dst, base_access,
|
|
dst_type, base,
|
|
src_type, src_ptr, result2);
|
|
result.whole2src = __sub_kind (result.whole2src | result2.whole2src);
|
|
if (result2.dst2src == __contained_public
|
|
|| result2.dst2src == __contained_ambig)
|
|
{
|
|
result.dst_ptr = result2.dst_ptr;
|
|
result.whole2dst = result2.whole2dst;
|
|
result.dst2src = result2.dst2src;
|
|
// Found a downcast which can't be bettered or an ambiguous downcast
|
|
// which can't be disambiguated
|
|
return result2_ambig;
|
|
}
|
|
|
|
if (!result_ambig && !result.dst_ptr)
|
|
{
|
|
// Not found anything yet.
|
|
result.dst_ptr = result2.dst_ptr;
|
|
result.whole2dst = result2.whole2dst;
|
|
result_ambig = result2_ambig;
|
|
if (result.dst_ptr && result.whole2src != __unknown
|
|
&& !(__flags & __non_diamond_repeat_mask))
|
|
// Found dst and src and we don't have repeated bases.
|
|
return result_ambig;
|
|
}
|
|
else if (result.dst_ptr && result.dst_ptr == result2.dst_ptr)
|
|
{
|
|
// Found at same address, must be via virtual. Pick the most
|
|
// accessible path.
|
|
result.whole2dst =
|
|
__sub_kind (result.whole2dst | result2.whole2dst);
|
|
}
|
|
else if ((result.dst_ptr != 0 | result_ambig)
|
|
&& (result2.dst_ptr != 0 | result2_ambig))
|
|
{
|
|
// Found two different DST_TYPE bases, or a valid one and a set of
|
|
// ambiguous ones, must disambiguate. See whether SRC_PTR is
|
|
// contained publicly within one of the non-ambiguous choices. If it
|
|
// is in only one, then that's the choice. If it is in both, then
|
|
// we're ambiguous and fail. If it is in neither, we're ambiguous,
|
|
// but don't yet fail as we might later find a third base which does
|
|
// contain SRC_PTR.
|
|
|
|
__sub_kind new_sub_kind = result2.dst2src;
|
|
__sub_kind old_sub_kind = result.dst2src;
|
|
|
|
if (contained_p (result.whole2src)
|
|
&& (!virtual_p (result.whole2src)
|
|
|| !(result.whole_details & __diamond_shaped_mask)))
|
|
{
|
|
// We already found SRC_PTR as a base of most derived, and
|
|
// either it was non-virtual, or the whole hierarchy is
|
|
// not-diamond shaped. Therefore if it is in either choice, it
|
|
// can only be in one of them, and we will already know.
|
|
if (old_sub_kind == __unknown)
|
|
old_sub_kind = __not_contained;
|
|
if (new_sub_kind == __unknown)
|
|
new_sub_kind = __not_contained;
|
|
}
|
|
else
|
|
{
|
|
if (old_sub_kind >= __not_contained)
|
|
;// already calculated
|
|
else if (contained_p (new_sub_kind)
|
|
&& (!virtual_p (new_sub_kind)
|
|
|| !(__flags & __diamond_shaped_mask)))
|
|
// Already found inside the other choice, and it was
|
|
// non-virtual or we are not diamond shaped.
|
|
old_sub_kind = __not_contained;
|
|
else
|
|
old_sub_kind = dst_type->__find_public_src
|
|
(src2dst, result.dst_ptr, src_type, src_ptr);
|
|
|
|
if (new_sub_kind >= __not_contained)
|
|
;// already calculated
|
|
else if (contained_p (old_sub_kind)
|
|
&& (!virtual_p (old_sub_kind)
|
|
|| !(__flags & __diamond_shaped_mask)))
|
|
// Already found inside the other choice, and it was
|
|
// non-virtual or we are not diamond shaped.
|
|
new_sub_kind = __not_contained;
|
|
else
|
|
new_sub_kind = dst_type->__find_public_src
|
|
(src2dst, result2.dst_ptr, src_type, src_ptr);
|
|
}
|
|
|
|
// Neither sub_kind can be contained_ambig -- we bail out early
|
|
// when we find those.
|
|
if (contained_p (__sub_kind (new_sub_kind ^ old_sub_kind)))
|
|
{
|
|
// Only on one choice, not ambiguous.
|
|
if (contained_p (new_sub_kind))
|
|
{
|
|
// Only in new.
|
|
result.dst_ptr = result2.dst_ptr;
|
|
result.whole2dst = result2.whole2dst;
|
|
result_ambig = false;
|
|
old_sub_kind = new_sub_kind;
|
|
}
|
|
result.dst2src = old_sub_kind;
|
|
if (public_p (result.dst2src))
|
|
return false; // Can't be an ambiguating downcast for later discovery.
|
|
if (!virtual_p (result.dst2src))
|
|
return false; // Found non-virtually can't be bettered
|
|
}
|
|
else if (contained_p (__sub_kind (new_sub_kind & old_sub_kind)))
|
|
{
|
|
// In both.
|
|
result.dst_ptr = NULL;
|
|
result.dst2src = __contained_ambig;
|
|
return true; // Fail.
|
|
}
|
|
else
|
|
{
|
|
// In neither publicly, ambiguous for the moment, but keep
|
|
// looking. It is possible that it was private in one or
|
|
// both and therefore we should fail, but that's just tough.
|
|
result.dst_ptr = NULL;
|
|
result.dst2src = __not_contained;
|
|
result_ambig = true;
|
|
}
|
|
}
|
|
|
|
if (result.whole2src == __contained_private)
|
|
// We found SRC_PTR as a private non-virtual base, therefore all
|
|
// cross casts will fail. We have already found a down cast, if
|
|
// there is one.
|
|
return result_ambig;
|
|
}
|
|
|
|
return result_ambig;
|
|
}
|
|
|
|
bool __class_type_info::
|
|
__do_upcast (const __class_type_info *dst, const void *obj,
|
|
__upcast_result &__restrict result) const
|
|
{
|
|
if (*this == *dst)
|
|
{
|
|
result.dst_ptr = obj;
|
|
result.base_type = nonvirtual_base_type;
|
|
result.part2dst = __contained_public;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool __si_class_type_info::
|
|
__do_upcast (const __class_type_info *dst, const void *obj_ptr,
|
|
__upcast_result &__restrict result) const
|
|
{
|
|
if (__class_type_info::__do_upcast (dst, obj_ptr, result))
|
|
return true;
|
|
|
|
return __base_type->__do_upcast (dst, obj_ptr, result);
|
|
}
|
|
|
|
bool __vmi_class_type_info::
|
|
__do_upcast (const __class_type_info *dst, const void *obj_ptr,
|
|
__upcast_result &__restrict result) const
|
|
{
|
|
if (__class_type_info::__do_upcast (dst, obj_ptr, result))
|
|
return true;
|
|
|
|
int src_details = result.src_details;
|
|
if (src_details & __flags_unknown_mask)
|
|
src_details = __flags;
|
|
|
|
for (std::size_t i = __base_count; i--;)
|
|
{
|
|
__upcast_result result2 (src_details);
|
|
const void *base = obj_ptr;
|
|
ptrdiff_t offset = __base_info[i].__offset ();
|
|
bool is_virtual = __base_info[i].__is_virtual_p ();
|
|
bool is_public = __base_info[i].__is_public_p ();
|
|
|
|
if (!is_public && !(src_details & __non_diamond_repeat_mask))
|
|
// original cannot have an ambiguous base, so skip private bases
|
|
continue;
|
|
|
|
if (base)
|
|
base = convert_to_base (base, is_virtual, offset);
|
|
|
|
if (__base_info[i].__base_type->__do_upcast (dst, base, result2))
|
|
{
|
|
if (result2.base_type == nonvirtual_base_type && is_virtual)
|
|
result2.base_type = __base_info[i].__base_type;
|
|
if (contained_p (result2.part2dst) && !is_public)
|
|
result2.part2dst = __sub_kind (result2.part2dst & ~__contained_public_mask);
|
|
|
|
if (!result.base_type)
|
|
{
|
|
result = result2;
|
|
if (!contained_p (result.part2dst))
|
|
return true; // found ambiguously
|
|
|
|
if (result.part2dst & __contained_public_mask)
|
|
{
|
|
if (!(__flags & __non_diamond_repeat_mask))
|
|
return true; // cannot have an ambiguous other base
|
|
}
|
|
else
|
|
{
|
|
if (!virtual_p (result.part2dst))
|
|
return true; // cannot have another path
|
|
if (!(__flags & __diamond_shaped_mask))
|
|
return true; // cannot have a more accessible path
|
|
}
|
|
}
|
|
else if (result.dst_ptr != result2.dst_ptr)
|
|
{
|
|
// Found an ambiguity.
|
|
result.dst_ptr = NULL;
|
|
result.part2dst = __contained_ambig;
|
|
return true;
|
|
}
|
|
else if (result.dst_ptr)
|
|
{
|
|
// Ok, found real object via a virtual path.
|
|
result.part2dst
|
|
= __sub_kind (result.part2dst | result2.part2dst);
|
|
}
|
|
else
|
|
{
|
|
// Dealing with a null pointer, need to check vbase
|
|
// containing each of the two choices.
|
|
if (result2.base_type == nonvirtual_base_type
|
|
|| result.base_type == nonvirtual_base_type
|
|
|| !(*result2.base_type == *result.base_type))
|
|
{
|
|
// Already ambiguous, not virtual or via different virtuals.
|
|
// Cannot match.
|
|
result.part2dst = __contained_ambig;
|
|
return true;
|
|
}
|
|
result.part2dst
|
|
= __sub_kind (result.part2dst | result2.part2dst);
|
|
}
|
|
}
|
|
}
|
|
return result.part2dst != __unknown;
|
|
}
|
|
|
|
// this is the external interface to the dynamic cast machinery
|
|
extern "C" void *
|
|
__dynamic_cast (const void *src_ptr, // object started from
|
|
const __class_type_info *src_type, // type of the starting object
|
|
const __class_type_info *dst_type, // desired target type
|
|
ptrdiff_t src2dst) // how src and dst are related
|
|
{
|
|
const void *vtable = *static_cast <const void *const *> (src_ptr);
|
|
const vtable_prefix *prefix =
|
|
adjust_pointer <vtable_prefix> (vtable,
|
|
-offsetof (vtable_prefix, origin));
|
|
const void *whole_ptr =
|
|
adjust_pointer <void> (src_ptr, prefix->whole_object);
|
|
const __class_type_info *whole_type = prefix->whole_type;
|
|
__class_type_info::__dyncast_result result;
|
|
|
|
whole_type->__do_dyncast (src2dst, __class_type_info::__contained_public,
|
|
dst_type, whole_ptr, src_type, src_ptr, result);
|
|
if (!result.dst_ptr)
|
|
return NULL;
|
|
if (contained_public_p (result.dst2src))
|
|
// Src is known to be a public base of dst.
|
|
return const_cast <void *> (result.dst_ptr);
|
|
if (contained_public_p (__class_type_info::__sub_kind (result.whole2src & result.whole2dst)))
|
|
// Both src and dst are known to be public bases of whole. Found a valid
|
|
// cross cast.
|
|
return const_cast <void *> (result.dst_ptr);
|
|
if (contained_nonvirtual_p (result.whole2src))
|
|
// Src is known to be a non-public nonvirtual base of whole, and not a
|
|
// base of dst. Found an invalid cross cast, which cannot also be a down
|
|
// cast
|
|
return NULL;
|
|
if (result.dst2src == __class_type_info::__unknown)
|
|
result.dst2src = dst_type->__find_public_src (src2dst, result.dst_ptr,
|
|
src_type, src_ptr);
|
|
if (contained_public_p (result.dst2src))
|
|
// Found a valid down cast
|
|
return const_cast <void *> (result.dst_ptr);
|
|
// Must be an invalid down cast, or the cross cast wasn't bettered
|
|
return NULL;
|
|
}
|
|
|
|
}; // namespace __cxxabiv1
|