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ba87515fea
Currently, the library-internal feature test macros are only defined if the feature is not available, and always have the prefix `_LIBCPP_HAS_NO_`. This patch changes that, so that they are always defined and have the prefix `_LIBCPP_HAS_` instead. This changes the canonical use of these macros to `#if _LIBCPP_HAS_FEATURE`, which means that using an undefined macro (e.g. due to a missing include) is diagnosed now. While this is rather unlikely currently, a similar change in `<__configuration/availability.h>` caught a few bugs. This also improves readability, since it removes the double-negation of `#ifndef _LIBCPP_HAS_NO_FEATURE`. The current patch only touches the macros defined in `<__config>`. If people are happy with this approach, I'll make a follow-up PR to also change the macros defined in `<__config_site>`.
102 lines
3.5 KiB
C++
102 lines
3.5 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___EXCEPTION_NESTED_EXCEPTION_H
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#define _LIBCPP___EXCEPTION_NESTED_EXCEPTION_H
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#include <__config>
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#include <__exception/exception_ptr.h>
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#include <__memory/addressof.h>
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#include <__type_traits/decay.h>
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#include <__type_traits/enable_if.h>
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#include <__type_traits/integral_constant.h>
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#include <__type_traits/is_base_of.h>
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#include <__type_traits/is_class.h>
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#include <__type_traits/is_constructible.h>
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#include <__type_traits/is_convertible.h>
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#include <__type_traits/is_final.h>
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#include <__type_traits/is_polymorphic.h>
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#include <__utility/forward.h>
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#include <cstddef>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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namespace std { // purposefully not using versioning namespace
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class _LIBCPP_EXPORTED_FROM_ABI nested_exception {
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exception_ptr __ptr_;
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public:
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nested_exception() _NOEXCEPT;
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_LIBCPP_HIDE_FROM_ABI nested_exception(const nested_exception&) _NOEXCEPT = default;
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_LIBCPP_HIDE_FROM_ABI nested_exception& operator=(const nested_exception&) _NOEXCEPT = default;
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virtual ~nested_exception() _NOEXCEPT;
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// access functions
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[[__noreturn__]] void rethrow_nested() const;
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_LIBCPP_HIDE_FROM_ABI exception_ptr nested_ptr() const _NOEXCEPT { return __ptr_; }
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};
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template <class _Tp>
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struct __nested : public _Tp, public nested_exception {
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_LIBCPP_HIDE_FROM_ABI explicit __nested(const _Tp& __t) : _Tp(__t) {}
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};
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#if _LIBCPP_HAS_EXCEPTIONS
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template <class _Tp, class _Up, bool>
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struct __throw_with_nested;
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template <class _Tp, class _Up>
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struct __throw_with_nested<_Tp, _Up, true> {
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[[__noreturn__]] static inline _LIBCPP_HIDE_FROM_ABI void __do_throw(_Tp&& __t) {
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throw __nested<_Up>(std::forward<_Tp>(__t));
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}
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};
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template <class _Tp, class _Up>
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struct __throw_with_nested<_Tp, _Up, false> {
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[[__noreturn__]] static inline _LIBCPP_HIDE_FROM_ABI void __do_throw(_Tp&& __t) { throw std::forward<_Tp>(__t); }
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};
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#endif
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template <class _Tp>
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[[__noreturn__]] _LIBCPP_HIDE_FROM_ABI void throw_with_nested(_Tp&& __t) {
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#if _LIBCPP_HAS_EXCEPTIONS
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using _Up = __decay_t<_Tp>;
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static_assert(is_copy_constructible<_Up>::value, "type thrown must be CopyConstructible");
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__throw_with_nested<_Tp,
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_Up,
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is_class<_Up>::value && !is_base_of<nested_exception, _Up>::value &&
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!__libcpp_is_final<_Up>::value>::__do_throw(std::forward<_Tp>(__t));
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#else
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((void)__t);
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// FIXME: Make this abort
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#endif
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}
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template <class _From, class _To>
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struct __can_dynamic_cast
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: _BoolConstant< is_polymorphic<_From>::value &&
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(!is_base_of<_To, _From>::value || is_convertible<const _From*, const _To*>::value)> {};
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template <class _Ep, __enable_if_t< __can_dynamic_cast<_Ep, nested_exception>::value, int> = 0>
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inline _LIBCPP_HIDE_FROM_ABI void rethrow_if_nested(const _Ep& __e) {
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const nested_exception* __nep = dynamic_cast<const nested_exception*>(std::addressof(__e));
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if (__nep)
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__nep->rethrow_nested();
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}
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template <class _Ep, __enable_if_t<!__can_dynamic_cast<_Ep, nested_exception>::value, int> = 0>
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inline _LIBCPP_HIDE_FROM_ABI void rethrow_if_nested(const _Ep&) {}
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} // namespace std
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#endif // _LIBCPP___EXCEPTION_NESTED_EXCEPTION_H
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