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

88 lines
2.9 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_COPY_IF_H
#define _LIBCPP___ALGORITHM_RANGES_COPY_IF_H
#include <__algorithm/in_out_result.h>
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
#include <__iterator/concepts.h>
#include <__iterator/projected.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 _Ip, class _Op>
using copy_if_result = in_out_result<_Ip, _Op>;
namespace __copy_if {
struct __fn {
template <class _InIter, class _Sent, class _OutIter, class _Proj, class _Pred>
_LIBCPP_HIDE_FROM_ABI static constexpr copy_if_result<_InIter, _OutIter>
__copy_if_impl(_InIter __first, _Sent __last, _OutIter __result, _Pred& __pred, _Proj& __proj) {
for (; __first != __last; ++__first) {
if (std::invoke(__pred, std::invoke(__proj, *__first))) {
*__result = *__first;
++__result;
}
}
return {std::move(__first), std::move(__result)};
}
template <input_iterator _Iter,
sentinel_for<_Iter> _Sent,
weakly_incrementable _OutIter,
class _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires indirectly_copyable<_Iter, _OutIter>
_LIBCPP_HIDE_FROM_ABI constexpr copy_if_result<_Iter, _OutIter>
operator()(_Iter __first, _Sent __last, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
return __copy_if_impl(std::move(__first), std::move(__last), std::move(__result), __pred, __proj);
}
template <input_range _Range,
weakly_incrementable _OutIter,
class _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
requires indirectly_copyable<iterator_t<_Range>, _OutIter>
_LIBCPP_HIDE_FROM_ABI constexpr copy_if_result<borrowed_iterator_t<_Range>, _OutIter>
operator()(_Range&& __r, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
return __copy_if_impl(ranges::begin(__r), ranges::end(__r), std::move(__result), __pred, __proj);
}
};
} // namespace __copy_if
inline namespace __cpo {
inline constexpr auto copy_if = __copy_if::__fn{};
} // namespace __cpo
} // namespace ranges
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_RANGES_COPY_IF_H