llvm-capstone/libcxx/include/__algorithm/pstl_copy.h
Louis Dionne 615e6dd1c5
[🍒][libc++] Fix missing and incorrect push/pop macros (#79204) (#79497)
We recently noticed that the unwrap_iter.h file was pushing macros, but
it was pushing them again instead of popping them at the end of the
file. This led to libc++ basically swallowing any custom definition of
these macros in user code:

    #define min HELLO
    #include <algorithm>
    // min is not HELLO anymore, it's not defined

While investigating this issue, I noticed that our push/pop pragmas were
actually entirely wrong too. Indeed, instead of pushing macros like
`move`, we'd push `move(int, int)` in the pragma, which is not a valid
macro name. As a result, we would not actually push macros like `move`
-- instead we'd simply undefine them. This led to the following code not
working:

    #define move HELLO
    #include <algorithm>
    // move is not HELLO anymore

Fixing the pragma push/pop incantations led to a cascade of issues
because we use identifiers like `move` in a large number of places, and
all of these headers would now need to do the push/pop dance.

This patch fixes all these issues. First, it adds a check that we don't
swallow important names like min, max, move or refresh as explained
above. This is done by augmenting the existing
system_reserved_names.gen.py test to also check that the macros are what
we expect after including each header.

Second, it fixes the push/pop pragmas to work properly and adds missing
pragmas to all the files I could detect a failure in via the newly added
test.

rdar://121365472
(cherry picked from commit 7b4622514d232ce5f7110dd8b20d90e81127c467)
2024-02-01 17:51:34 -08:00

122 lines
4.6 KiB
C++

//===----------------------------------------------------------------------===//
//
// 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___ALGORITHM_PSTL_COPY_H
#define _LIBCPP___ALGORITHM_PSTL_COPY_H
#include <__algorithm/copy_n.h>
#include <__algorithm/pstl_backend.h>
#include <__algorithm/pstl_frontend_dispatch.h>
#include <__algorithm/pstl_transform.h>
#include <__config>
#include <__functional/identity.h>
#include <__iterator/concepts.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/is_constant_evaluated.h>
#include <__type_traits/is_execution_policy.h>
#include <__type_traits/is_trivially_copyable.h>
#include <__type_traits/remove_cvref.h>
#include <__utility/move.h>
#include <optional>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
_LIBCPP_BEGIN_NAMESPACE_STD
// TODO: Use the std::copy/move shenanigans to forward to std::memmove
template <class>
void __pstl_copy();
template <class _ExecutionPolicy,
class _ForwardIterator,
class _ForwardOutIterator,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator>
__copy(_ExecutionPolicy&& __policy,
_ForwardIterator&& __first,
_ForwardIterator&& __last,
_ForwardOutIterator&& __result) noexcept {
return std::__pstl_frontend_dispatch(
_LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_copy, _RawPolicy),
[&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last, _ForwardOutIterator __g_result) {
return std::__transform(__policy, __g_first, __g_last, __g_result, __identity());
},
std::move(__first),
std::move(__last),
std::move(__result));
}
template <class _ExecutionPolicy,
class _ForwardIterator,
class _ForwardOutIterator,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
copy(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __result) {
auto __res = std::__copy(__policy, std::move(__first), std::move(__last), std::move(__result));
if (!__res)
std::__throw_bad_alloc();
return *std::move(__res);
}
template <class>
void __pstl_copy_n();
template <class _ExecutionPolicy,
class _ForwardIterator,
class _ForwardOutIterator,
class _Size,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator> __copy_n(
_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _Size&& __n, _ForwardOutIterator&& __result) noexcept {
return std::__pstl_frontend_dispatch(
_LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_copy_n, _RawPolicy),
[&__policy](
_ForwardIterator __g_first, _Size __g_n, _ForwardOutIterator __g_result) -> optional<_ForwardIterator> {
if constexpr (__has_random_access_iterator_category_or_concept<_ForwardIterator>::value)
return std::__copy(__policy, std::move(__g_first), std::move(__g_first + __g_n), std::move(__g_result));
else
return std::copy_n(__g_first, __g_n, __g_result);
},
std::move(__first),
std::move(__n),
std::move(__result));
}
template <class _ExecutionPolicy,
class _ForwardIterator,
class _ForwardOutIterator,
class _Size,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
copy_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __n, _ForwardOutIterator __result) {
auto __res = std::__copy_n(__policy, std::move(__first), std::move(__n), std::move(__result));
if (!__res)
std::__throw_bad_alloc();
return *std::move(__res);
}
_LIBCPP_END_NAMESPACE_STD
#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_PSTL_COPY_H