[🍒][libc++] Fix missing and incorrect push/pop macros (llvm#79204) (llvm#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 7b46225)

Author: ldionne

libcxx/include/__algorithm/copy_move_common.h

@@ -31,6 +31,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 // Type traits.
@@ -132,4 +135,6 @@ __dispatch_copy_or_move(_InIter __first, _Sent __last, _OutIter __out_first) {
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H

libcxx/include/__algorithm/equal.h

@@ -30,6 +30,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
@@ -162,4 +165,6 @@ equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_EQUAL_H

libcxx/include/__algorithm/equal_range.h

@@ -31,6 +31,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _AlgPolicy, class _Compare, class _Iter, class _Sent, class _Tp, class _Proj>
@@ -77,4 +80,6 @@ equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __valu
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H

libcxx/include/__algorithm/fold.h

@@ -32,6 +32,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 23
@@ -122,4 +125,6 @@ inline constexpr auto fold_left = __fold_left();
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_FOLD_H

libcxx/include/__algorithm/in_found_result.h

@@ -18,6 +18,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 #if _LIBCPP_STD_VER >= 20
 
 _LIBCPP_BEGIN_NAMESPACE_STD
@@ -46,4 +49,6 @@ _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP_STD_VER >= 20
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_IN_FOUND_RESULT_H

libcxx/include/__algorithm/in_fun_result.h

@@ -18,6 +18,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
@@ -46,4 +49,6 @@ struct in_fun_result {
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_IN_FUN_RESULT_H

libcxx/include/__algorithm/in_in_out_result.h

@@ -18,6 +18,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
@@ -51,4 +54,6 @@ struct in_in_out_result {
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_IN_IN_OUT_RESULT_H

libcxx/include/__algorithm/in_in_result.h

@@ -18,6 +18,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
@@ -48,4 +51,6 @@ struct in_in_result {
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_IN_IN_RESULT_H

libcxx/include/__algorithm/in_out_out_result.h

@@ -18,6 +18,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
@@ -49,4 +52,6 @@ struct in_out_out_result {
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_IN_OUT_OUT_RESULT_H

libcxx/include/__algorithm/includes.h

@@ -22,6 +22,9 @@
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Comp, class _Proj1, class _Proj2>
@@ -71,4 +74,6 @@ includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __fi
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_INCLUDES_H