llvm-project/libcxx/include/__algorithm/ranges_swap_ranges.h
Louis Dionne 7b4622514d
[libc++] Fix missing and incorrect push/pop macros (#79204)
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
2024-01-25 15:48:46 -05:00

71 lines
2.2 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_RANGES_SWAP_RANGES_H
#define _LIBCPP___ALGORITHM_RANGES_SWAP_RANGES_H
#include <__algorithm/in_in_result.h>
#include <__algorithm/iterator_operations.h>
#include <__algorithm/swap_ranges.h>
#include <__config>
#include <__iterator/concepts.h>
#include <__iterator/iter_swap.h>
#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__ranges/dangling.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
#if _LIBCPP_STD_VER >= 20
_LIBCPP_BEGIN_NAMESPACE_STD
namespace ranges {
template <class _I1, class _I2>
using swap_ranges_result = in_in_result<_I1, _I2>;
namespace __swap_ranges {
struct __fn {
template <input_iterator _I1, sentinel_for<_I1> _S1, input_iterator _I2, sentinel_for<_I2> _S2>
requires indirectly_swappable<_I1, _I2>
_LIBCPP_HIDE_FROM_ABI constexpr swap_ranges_result<_I1, _I2>
operator()(_I1 __first1, _S1 __last1, _I2 __first2, _S2 __last2) const {
auto __ret = std::__swap_ranges<_RangeAlgPolicy>(
std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2));
return {std::move(__ret.first), std::move(__ret.second)};
}
template <input_range _R1, input_range _R2>
requires indirectly_swappable<iterator_t<_R1>, iterator_t<_R2>>
_LIBCPP_HIDE_FROM_ABI constexpr swap_ranges_result<borrowed_iterator_t<_R1>, borrowed_iterator_t<_R2>>
operator()(_R1&& __r1, _R2&& __r2) const {
return operator()(ranges::begin(__r1), ranges::end(__r1), ranges::begin(__r2), ranges::end(__r2));
}
};
} // namespace __swap_ranges
inline namespace __cpo {
inline constexpr auto swap_ranges = __swap_ranges::__fn{};
} // namespace __cpo
} // namespace ranges
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_RANGES_SWAP_RANGES_H