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

106 lines
3.6 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_SET_UNION_H
#define _LIBCPP___ALGORITHM_SET_UNION_H
#include <__algorithm/comp.h>
#include <__algorithm/comp_ref_type.h>
#include <__algorithm/copy.h>
#include <__algorithm/iterator_operations.h>
#include <__config>
#include <__iterator/iterator_traits.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 _InIter1, class _InIter2, class _OutIter>
struct __set_union_result {
_InIter1 __in1_;
_InIter2 __in2_;
_OutIter __out_;
// need a constructor as C++03 aggregate init is hard
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
__set_union_result(_InIter1&& __in_iter1, _InIter2&& __in_iter2, _OutIter&& __out_iter)
: __in1_(std::move(__in_iter1)), __in2_(std::move(__in_iter2)), __out_(std::move(__out_iter)) {}
};
template <class _AlgPolicy, class _Compare, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __set_union_result<_InIter1, _InIter2, _OutIter> __set_union(
_InIter1 __first1, _Sent1 __last1, _InIter2 __first2, _Sent2 __last2, _OutIter __result, _Compare&& __comp) {
for (; __first1 != __last1; ++__result) {
if (__first2 == __last2) {
auto __ret1 = std::__copy<_AlgPolicy>(std::move(__first1), std::move(__last1), std::move(__result));
return __set_union_result<_InIter1, _InIter2, _OutIter>(
std::move(__ret1.first), std::move(__first2), std::move((__ret1.second)));
}
if (__comp(*__first2, *__first1)) {
*__result = *__first2;
++__first2;
} else {
if (!__comp(*__first1, *__first2)) {
++__first2;
}
*__result = *__first1;
++__first1;
}
}
auto __ret2 = std::__copy<_AlgPolicy>(std::move(__first2), std::move(__last2), std::move(__result));
return __set_union_result<_InIter1, _InIter2, _OutIter>(
std::move(__first1), std::move(__ret2.first), std::move((__ret2.second)));
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_union(
_InputIterator1 __first1,
_InputIterator1 __last1,
_InputIterator2 __first2,
_InputIterator2 __last2,
_OutputIterator __result,
_Compare __comp) {
return std::__set_union<_ClassicAlgPolicy, __comp_ref_type<_Compare> >(
std::move(__first1),
std::move(__last1),
std::move(__first2),
std::move(__last2),
std::move(__result),
__comp)
.__out_;
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_union(
_InputIterator1 __first1,
_InputIterator1 __last1,
_InputIterator2 __first2,
_InputIterator2 __last2,
_OutputIterator __result) {
return std::set_union(
std::move(__first1),
std::move(__last1),
std::move(__first2),
std::move(__last2),
std::move(__result),
__less<>());
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_SET_UNION_H