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

80 lines
2.7 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_SET_DIFFERENCE_H
#define _LIBCPP___ALGORITHM_SET_DIFFERENCE_H
#include <__algorithm/comp.h>
#include <__algorithm/comp_ref_type.h>
#include <__algorithm/copy.h>
#include <__algorithm/iterator_operations.h>
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
#include <__iterator/iterator_traits.h>
#include <__type_traits/remove_cvref.h>
#include <__utility/move.h>
#include <__utility/pair.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _AlgPolicy, class _Comp, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__remove_cvref_t<_InIter1>, __remove_cvref_t<_OutIter> >
__set_difference(
_InIter1&& __first1, _Sent1&& __last1, _InIter2&& __first2, _Sent2&& __last2, _OutIter&& __result, _Comp&& __comp) {
while (__first1 != __last1 && __first2 != __last2) {
if (__comp(*__first1, *__first2)) {
*__result = *__first1;
++__first1;
++__result;
} else if (__comp(*__first2, *__first1)) {
++__first2;
} else {
++__first1;
++__first2;
}
}
return std::__copy<_AlgPolicy>(std::move(__first1), std::move(__last1), std::move(__result));
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_difference(
_InputIterator1 __first1,
_InputIterator1 __last1,
_InputIterator2 __first2,
_InputIterator2 __last2,
_OutputIterator __result,
_Compare __comp) {
return std::__set_difference<_ClassicAlgPolicy, __comp_ref_type<_Compare> >(
__first1, __last1, __first2, __last2, __result, __comp)
.second;
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_difference(
_InputIterator1 __first1,
_InputIterator1 __last1,
_InputIterator2 __first2,
_InputIterator2 __last2,
_OutputIterator __result) {
return std::__set_difference<_ClassicAlgPolicy>(__first1, __last1, __first2, __last2, __result, __less<>()).second;
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_SET_DIFFERENCE_H