[libc++] Fix padding calculation for function reference types#142125
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[libc++] Fix padding calculation for function reference types#142125
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@llvm/pr-subscribers-libcxx Author: A. Jiang (frederick-vs-ja) Changes#109028 caused Fixes #142118. Full diff: https://github.com/llvm/llvm-project/pull/142125.diff 2 Files Affected:
diff --git a/libcxx/include/__memory/compressed_pair.h b/libcxx/include/__memory/compressed_pair.h
index 38798a21fa3c9..fb7b7b7afcc8c 100644
--- a/libcxx/include/__memory/compressed_pair.h
+++ b/libcxx/include/__memory/compressed_pair.h
@@ -15,7 +15,6 @@
#include <__type_traits/datasizeof.h>
#include <__type_traits/is_empty.h>
#include <__type_traits/is_final.h>
-#include <__type_traits/is_reference.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
@@ -63,9 +62,17 @@ inline const size_t __compressed_pair_alignment = _LIBCPP_ALIGNOF(_Tp);
template <class _Tp>
inline const size_t __compressed_pair_alignment<_Tp&> = _LIBCPP_ALIGNOF(void*);
-template <class _ToPad,
- bool _Empty = ((is_empty<_ToPad>::value && !__libcpp_is_final<_ToPad>::value) ||
- is_reference<_ToPad>::value || sizeof(_ToPad) == __datasizeof_v<_ToPad>)>
+template <class _ToPad>
+inline const bool __is_reference_or_unpadded_object =
+ (is_empty<_ToPad>::value && !__libcpp_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>] = {};
};
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
index a91abc856fb19..a438bfb58ce44 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
@@ -32,6 +32,8 @@ bool my_free_called = false;
void my_free(void*) { my_free_called = true; }
+TEST_CONSTEXPR_CXX23 void deleter_function(A*) {}
+
#if TEST_STD_VER >= 11
struct DeleterBase {
TEST_CONSTEXPR_CXX23 void operator()(void*) const {}
@@ -325,6 +327,21 @@ TEST_CONSTEXPR_CXX23 void test_nullptr() {
#endif
}
+template <bool IsArray>
+TEST_CONSTEXPR_CXX23 void test_function_reference() {
+ typedef typename std::conditional<!IsArray, A, A[]>::type VT;
+ {
+ std::unique_ptr<VT, void (&)(A*)> u(nullptr, deleter_function);
+ assert(u.get() == nullptr);
+ assert(u.get_deleter() == deleter_function);
+ }
+ {
+ std::unique_ptr<VT, void (&)(A*)> u(nullptr, deleter_function);
+ assert(u.get() == nullptr);
+ assert(u.get_deleter() == deleter_function);
+ }
+}
+
TEST_CONSTEXPR_CXX23 bool test() {
{
test_basic</*IsArray*/ false>();
@@ -332,6 +349,7 @@ TEST_CONSTEXPR_CXX23 bool test() {
test_basic_single();
test_sfinae<false>();
test_noexcept<false>();
+ test_function_reference<false>();
}
{
test_basic</*IsArray*/ true>();
@@ -339,6 +357,7 @@ TEST_CONSTEXPR_CXX23 bool test() {
test_sfinae<true>();
test_sfinae_runtime();
test_noexcept<true>();
+ test_function_reference<true>();
}
return true;
|
shafik
reviewed
Jun 2, 2025
| template <class _ToPad, | ||
| bool _Empty = ((is_empty<_ToPad>::value && !__libcpp_is_final<_ToPad>::value) || | ||
| is_reference<_ToPad>::value || sizeof(_ToPad) == __datasizeof_v<_ToPad>)> | ||
| template <class _ToPad> |
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Do this have to be updated as well?
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Looks like that changes in lldbsuite should belong to another PR. I've opened #142516.
ldionne
approved these changes
Jun 3, 2025
1 task
Michael137
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to swiftlang/llvm-project
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Aug 26, 2025
…m#142516) This PR mirrors changes of `__compressed_pair_padding` in libc++ into lldb test suite. Related PR for libc++: - llvm#108956 - llvm#109028 - llvm#142125 (cherry picked from commit 119705e)
Michael137
pushed a commit
to swiftlang/llvm-project
that referenced
this pull request
Aug 26, 2025
…m#142516) This PR mirrors changes of `__compressed_pair_padding` in libc++ into lldb test suite. Related PR for libc++: - llvm#108956 - llvm#109028 - llvm#142125 (cherry picked from commit 119705e) (cherry picked from commit 205591b)
Michael137
pushed a commit
to swiftlang/llvm-project
that referenced
this pull request
Aug 26, 2025
…m#142516) This PR mirrors changes of `__compressed_pair_padding` in libc++ into lldb test suite. Related PR for libc++: - llvm#108956 - llvm#109028 - llvm#142125 (cherry picked from commit 119705e) (cherry picked from commit 205591b)
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#109028 caused
sizeofto be sometimes applied to function reference types, which makes a program ill-formed. This PR handles reference types by specializations to prevent such bogussizeofexpression to be instantiated.Fixes #142118.