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[lldb][test] Synchronize __compressed_pair_padding with libc++ #142516

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Merged
merged 4 commits into from
Jul 3, 2025
Merged

[lldb][test] Synchronize __compressed_pair_padding with libc++ #142516

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3e8a4bf
[lldb][test] Synchronize `__compressed_pair_padding` with libc++
frederick-vs-ja Jun 3, 2025
a755d83
Bump `COMPRESSED_PAIR_REV`
frederick-vs-ja Jun 18, 2025
21f55cc
Merge branch 'main' into lldb-test-sync-compressed-pair
frederick-vs-ja Jun 18, 2025
6b8a63a
Restore one missed line
frederick-vs-ja Jun 18, 2025
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26 changes: 24 additions & 2 deletions lldb/packages/Python/lldbsuite/test/make/libcxx-simulators-common/compressed_pair.h
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ class __compressed_pair : private __compressed_pair_elem<_T1, 0>,

_T1 &first() { return static_cast<_Base1 &>(*this).__get(); }
};
#elif COMPRESSED_PAIR_REV == 1
#elif COMPRESSED_PAIR_REV == 1 || COMPRESSED_PAIR_REV == 2
// From libc++ datasizeof.h
template <class _Tp> struct _FirstPaddingByte {
_LLDB_NO_UNIQUE_ADDRESS _Tp __v_;
Expand All @@ -72,13 +72,35 @@ inline const size_t __datasizeof_v =
template <class _Tp>
struct __lldb_is_final : public integral_constant<bool, __is_final(_Tp)> {};

// The legacy layout has been patched, see
// https://github.com/llvm/llvm-project/pull/142516.
#if COMPRESSED_PAIR_REV == 1
template <class _ToPad> class __compressed_pair_padding {
char __padding_[((is_empty<_ToPad>::value &&
!__lldb_is_final<_ToPad>::value) ||
is_reference<_ToPad>::value)
? 0
: sizeof(_ToPad) - __datasizeof_v<_ToPad>];
};
#else
template <class _ToPad>
inline const bool __is_reference_or_unpadded_object =
(std::is_empty<_ToPad>::value && !__lldb_is_final<_ToPad>::value) ||
sizeof(_ToPad) == __datasizeof_v<_ToPad>;

template <class _Tp>
inline const bool __is_reference_or_unpadded_object<_Tp &> = true;

template <class _Tp>
inline const bool __is_reference_or_unpadded_object<_Tp &&> = true;

template <class _ToPad, bool _Empty = __is_reference_or_unpadded_object<_ToPad>>
class __compressed_pair_padding {
char __padding_[sizeof(_ToPad) - __datasizeof_v<_ToPad>] = {};
};

template <class _ToPad> class __compressed_pair_padding<_ToPad, true> {};
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Thanks for keeping this in sync! What we would usually do with these simulators is to add the new implementation behind a ifdef COMPRESSED_PAIR_REV == <new version>. To make sure we don't regress users still on the older layout. Do you mind doing that? If it's too finicky I'm happy to give it a shot

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@frederick-vs-ja frederick-vs-ja Jun 18, 2025 •
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Sorry for late replying. I'll do this soon I've done this, although this seems unnecessary as there doesn't seem any case where the layout will change.

#endif

#define _LLDB_COMPRESSED_PAIR(T1, Initializer1, T2, Initializer2) \
[[__gnu__::__aligned__( \
Expand All @@ -96,7 +118,7 @@ template <class _ToPad> class __compressed_pair_padding {
_LLDB_NO_UNIQUE_ADDRESS __compressed_pair_padding<T2> __padding2_; \
_LLDB_NO_UNIQUE_ADDRESS T3 Initializer3; \
_LLDB_NO_UNIQUE_ADDRESS __compressed_pair_padding<T3> __padding3_;
#elif COMPRESSED_PAIR_REV == 2
#elif COMPRESSED_PAIR_REV == 3
#define _LLDB_COMPRESSED_PAIR(T1, Name1, T2, Name2) \
_LLDB_NO_UNIQUE_ADDRESS T1 Name1; \
_LLDB_NO_UNIQUE_ADDRESS T2 Name2
Expand Down
2 changes: 1 addition & 1 deletion ...nctionalities/data-formatter/data-formatter-stl/libcxx-simulators/invalid-vector/main.cpp
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@@ -1,4 +1,4 @@
#define COMPRESSED_PAIR_REV 2
#define COMPRESSED_PAIR_REV 3
#include <libcxx-simulators-common/compressed_pair.h>

namespace std {
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2 changes: 1 addition & 1 deletion ...ter/data-formatter-stl/libcxx-simulators/string/TestDataFormatterLibcxxStringSimulator.py
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Expand Up @@ -28,7 +28,7 @@ def _run_test(self, defines):

for v in [None, "ALTERNATE_LAYOUT"]:
for r in range(6):
for c in range(3):
for c in range(4):
name = "test_r%d_c%d" % (r, c)
defines = ["REVISION=%d" % r, "COMPRESSED_PAIR_REV=%d" % c]
if v:
Expand Down
6 changes: 3 additions & 3 deletions ...t/API/functionalities/data-formatter/data-formatter-stl/libcxx-simulators/string/main.cpp
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Expand Up @@ -209,22 +209,22 @@ template <class _CharT, class _Traits, class _Allocator> class basic_string {
__long &getLongRep() {
#if COMPRESSED_PAIR_REV == 0
return __r_.first().__l;
#elif COMPRESSED_PAIR_REV <= 2
#elif COMPRESSED_PAIR_REV <= 3
return __rep_.__l;
#endif
}

__short &getShortRep() {
#if COMPRESSED_PAIR_REV == 0
return __r_.first().__s;
#elif COMPRESSED_PAIR_REV <= 2
#elif COMPRESSED_PAIR_REV <= 3
return __rep_.__s;
#endif
}

#if COMPRESSED_PAIR_REV == 0
std::__lldb::__compressed_pair<__rep, allocator_type> __r_;
#elif COMPRESSED_PAIR_REV <= 2
#elif COMPRESSED_PAIR_REV <= 3
_LLDB_COMPRESSED_PAIR(__rep, __rep_, allocator_type, __alloc_);
#endif

Expand Down
2 changes: 1 addition & 1 deletion ...a-formatter-stl/libcxx-simulators/unique_ptr/TestDataFormatterLibcxxUniquePtrSimulator.py
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Expand Up @@ -26,7 +26,7 @@ def _run_test(self, defines):
)


for r in range(3):
for r in range(4):
name = "test_r%d" % r
defines = ["COMPRESSED_PAIR_REV=%d" % r]

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3 changes: 2 additions & 1 deletion ...I/functionalities/data-formatter/data-formatter-stl/libcxx-simulators/unique_ptr/main.cpp
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Expand Up @@ -20,7 +20,8 @@ template <class _Tp, class _Dp = default_delete<_Tp>> class unique_ptr {
std::__lldb::__compressed_pair<pointer, deleter_type> __ptr_;
explicit unique_ptr(pointer __p) noexcept
: __ptr_(__p, std::__lldb::__value_init_tag()) {}
#elif COMPRESSED_PAIR_REV == 1 || COMPRESSED_PAIR_REV == 2
#elif COMPRESSED_PAIR_REV == 1 || COMPRESSED_PAIR_REV == 2 || \
COMPRESSED_PAIR_REV == 3
_LLDB_COMPRESSED_PAIR(pointer, __ptr_, deleter_type, __deleter_);
explicit unique_ptr(pointer __p) noexcept : __ptr_(__p), __deleter_() {}
#endif
Expand Down
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