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// -*- C++ -*-
//===-------------------------- typeinfo ----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef __LIBCPP_TYPEINFO
#define __LIBCPP_TYPEINFO
/*
typeinfo synopsis
namespace std {
class type_info
{
public:
virtual ~type_info();
bool operator==(const type_info& rhs) const noexcept;
bool operator!=(const type_info& rhs) const noexcept;
bool before(const type_info& rhs) const noexcept;
size_t hash_code() const noexcept;
const char* name() const noexcept;
type_info(const type_info& rhs) = delete;
type_info& operator=(const type_info& rhs) = delete;
};
class bad_cast
: public exception
{
public:
bad_cast() noexcept;
bad_cast(const bad_cast&) noexcept;
bad_cast& operator=(const bad_cast&) noexcept;
virtual const char* what() const noexcept;
};
class bad_typeid
: public exception
{
public:
bad_typeid() noexcept;
bad_typeid(const bad_typeid&) noexcept;
bad_typeid& operator=(const bad_typeid&) noexcept;
virtual const char* what() const noexcept;
};
} // std
*/
#include <__config>
#include <exception>
#include <cstddef>
#include <cstdint>
#ifdef _LIBCPP_NO_EXCEPTIONS
#include <cstdlib>
#endif
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
#if defined(_LIBCPP_ABI_VCRUNTIME)
#include <vcruntime_typeinfo.h>
#else
#if defined(_LIBCPP_NONUNIQUE_RTTI_BIT) && !defined(_LIBCPP_ABI_MICROSOFT)
# define _LIBCPP_HAS_NONUNIQUE_TYPEINFO
#endif
namespace std // purposefully not using versioning namespace
{
#if defined(_LIBCPP_ABI_MICROSOFT)
class _LIBCPP_EXCEPTION_ABI type_info
{
type_info& operator=(const type_info&);
type_info(const type_info&);
mutable struct {
const char *__undecorated_name;
const char __decorated_name[1];
} __data;
int __compare(const type_info &__rhs) const _NOEXCEPT;
public:
_LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
virtual ~type_info();
const char *name() const _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY
bool before(const type_info& __arg) const _NOEXCEPT {
return __compare(__arg) < 0;
}
size_t hash_code() const _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY
bool operator==(const type_info& __arg) const _NOEXCEPT {
return __compare(__arg) == 0;
}
_LIBCPP_INLINE_VISIBILITY
bool operator!=(const type_info& __arg) const _NOEXCEPT
{ return !operator==(__arg); }
};
#elif defined(_LIBCPP_HAS_NONUNIQUE_TYPEINFO)
// This implementation of type_info does not assume always a unique copy of
// the RTTI for a given type inside a program. It packs the pointer to the
// type name into a uintptr_t and reserves the high bit of that pointer (which
// is assumed to be free for use under the ABI in use) to represent whether
// that specific copy of the RTTI can be assumed unique inside the program.
// To implement equality-comparison of type_infos, we check whether BOTH
// type_infos are guaranteed unique, and if so, we simply compare the addresses
// of their type names instead of doing a deep string comparison, which is
// faster. If at least one of the type_infos can't guarantee uniqueness, we
// have no choice but to fall back to a deep string comparison.
//
// Note that the compiler is the one setting (or unsetting) the high bit of
// the pointer when it constructs the type_info, depending on whether it can
// guarantee uniqueness for that specific type_info.
class _LIBCPP_EXCEPTION_ABI type_info
{
type_info& operator=(const type_info&);
type_info(const type_info&);
_LIBCPP_INLINE_VISIBILITY
int __compare_nonunique_names(const type_info &__arg) const _NOEXCEPT
{ return __builtin_strcmp(name(), __arg.name()); }
protected:
uintptr_t __type_name;
_LIBCPP_INLINE_VISIBILITY
explicit type_info(const char* __n)
: __type_name(reinterpret_cast<uintptr_t>(__n)) {}
public:
_LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
virtual ~type_info();
_LIBCPP_INLINE_VISIBILITY
const char* name() const _NOEXCEPT
{
return reinterpret_cast<const char*>(__type_name &
~_LIBCPP_NONUNIQUE_RTTI_BIT);
}
_LIBCPP_INLINE_VISIBILITY
bool before(const type_info& __arg) const _NOEXCEPT
{
if (!((__type_name & __arg.__type_name) & _LIBCPP_NONUNIQUE_RTTI_BIT))
return __type_name < __arg.__type_name;
return __compare_nonunique_names(__arg) < 0;
}
_LIBCPP_INLINE_VISIBILITY
size_t hash_code() const _NOEXCEPT
{
if (!(__type_name & _LIBCPP_NONUNIQUE_RTTI_BIT))
return __type_name;
const char* __ptr = name();
size_t __hash = 5381;
while (unsigned char __c = static_cast<unsigned char>(*__ptr++))
__hash = (__hash * 33) ^ __c;
return __hash;
}
_LIBCPP_INLINE_VISIBILITY
bool operator==(const type_info& __arg) const _NOEXCEPT
{
if (__type_name == __arg.__type_name)
return true;
if (!((__type_name & __arg.__type_name) & _LIBCPP_NONUNIQUE_RTTI_BIT))
return false;
return __compare_nonunique_names(__arg) == 0;
}
_LIBCPP_INLINE_VISIBILITY
bool operator!=(const type_info& __arg) const _NOEXCEPT
{ return !operator==(__arg); }
};
#else // !_LIBCPP_ABI_MICROSOFT && !_LIBCPP_HAS_NONUNIQUE_TYPEINFO
// This implementation of type_info assumes a unique copy of the RTTI for a
// given type inside a program. This is a valid assumption when abiding to
// Itanium ABI (http://itanium-cxx-abi.github.io/cxx-abi/abi.html#vtable-components).
// Under this assumption, we can always compare the addresses of the type names
// to implement equality-comparison of type_infos instead of having to perform
// a deep string comparison.
class _LIBCPP_EXCEPTION_ABI type_info
{
type_info& operator=(const type_info&);
type_info(const type_info&);
protected:
const char *__type_name;
_LIBCPP_INLINE_VISIBILITY
explicit type_info(const char* __n) : __type_name(__n) {}
public:
_LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
virtual ~type_info();
_LIBCPP_INLINE_VISIBILITY
const char* name() const _NOEXCEPT
{ return __type_name; }
_LIBCPP_INLINE_VISIBILITY
bool before(const type_info& __arg) const _NOEXCEPT
{ return __type_name < __arg.__type_name; }
_LIBCPP_INLINE_VISIBILITY
size_t hash_code() const _NOEXCEPT
{ return reinterpret_cast<size_t>(__type_name); }
_LIBCPP_INLINE_VISIBILITY
bool operator==(const type_info& __arg) const _NOEXCEPT
{ return __type_name == __arg.__type_name; }
_LIBCPP_INLINE_VISIBILITY
bool operator!=(const type_info& __arg) const _NOEXCEPT
{ return !operator==(__arg); }
};
#endif
class _LIBCPP_EXCEPTION_ABI bad_cast
: public exception
{
public:
bad_cast() _NOEXCEPT;
virtual ~bad_cast() _NOEXCEPT;
virtual const char* what() const _NOEXCEPT;
};
class _LIBCPP_EXCEPTION_ABI bad_typeid
: public exception
{
public:
bad_typeid() _NOEXCEPT;
virtual ~bad_typeid() _NOEXCEPT;
virtual const char* what() const _NOEXCEPT;
};
} // std
#endif // defined(_LIBCPP_ABI_VCRUNTIME)
_LIBCPP_BEGIN_NAMESPACE_STD
_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
void __throw_bad_cast()
{
#ifndef _LIBCPP_NO_EXCEPTIONS
throw bad_cast();
#else
_VSTD::abort();
#endif
}
_LIBCPP_END_NAMESPACE_STD
#endif // __LIBCPP_TYPEINFO