================
@@ -1558,6 +1558,89 @@ void is_standard_layout()
int t71[F(__is_standard_layout(HasEmptyIndirectBaseAsSecondUnionMember))];
}
+struct CStruct2 {
+ int one;
+ int two;
+};
+
+struct CEmptyStruct2 {};
+
+struct CppEmptyStruct2 : CStruct2 {};
+struct CppStructStandard2 : CEmptyStruct2 {
+ int three;
+ int four;
+};
+struct CppStructNonStandardByBase2 : CStruct2 {
+ int three;
+ int four;
+};
+struct CppStructNonStandardByVirt2 : CStruct2 {
+ virtual void method() {}
+};
+struct CppStructNonStandardByMemb2 : CStruct2 {
+ CppStructNonStandardByVirt member;
+};
+struct CppStructNonStandardByProt2 : CStruct2 {
+ int five;
+protected:
+ int six;
+};
+struct CppStructNonStandardByVirtBase2 : virtual CStruct2 {
+};
+struct CppStructNonStandardBySameBase2 : CEmptyStruct2 {
+ CEmptyStruct member;
+};
+struct CppStructNonStandardBy2ndVirtBase2 : CEmptyStruct2 {
+ CEmptyStruct member;
+};
+
+struct CStructWithQualifiers {
+ const int one;
+ volatile int two;
+};
+
+struct CStructNoUniqueAddress {
+ int one;
+ [[no_unique_address]] int two;
+};
+
+struct CStructNoUniqueAddress2 {
+ int one;
+ [[no_unique_address]] int two;
+};
+
+struct CStructAlignment {
+ int one;
+ alignas(16) int two;
+};
+
+struct CStructIncomplete;
+
+void is_layout_compatible()
+{
+ static_assert(__is_layout_compatible(void, void), "");
+ static_assert(__is_layout_compatible(int, int), "");
+ static_assert(__is_layout_compatible(int[], int[]), "");
+ static_assert(__is_layout_compatible(int[2], int[2]), "");
+ static_assert(__is_layout_compatible(CStruct, CStruct2), "");
+ static_assert(__is_layout_compatible(CEmptyStruct, CEmptyStruct2), "");
+ static_assert(__is_layout_compatible(CppEmptyStruct, CppEmptyStruct2), "");
+ static_assert(__is_layout_compatible(CppStructStandard, CppStructStandard2),
"");
+ static_assert(!__is_layout_compatible(CppStructNonStandardByBase,
CppStructNonStandardByBase2), "");
+ static_assert(!__is_layout_compatible(CppStructNonStandardByVirt,
CppStructNonStandardByVirt2), "");
+ static_assert(!__is_layout_compatible(CppStructNonStandardByMemb,
CppStructNonStandardByMemb2), "");
+ static_assert(!__is_layout_compatible(CppStructNonStandardByProt,
CppStructNonStandardByProt2), "");
+ static_assert(!__is_layout_compatible(CppStructNonStandardByVirtBase,
CppStructNonStandardByVirtBase2), "");
+ static_assert(!__is_layout_compatible(CppStructNonStandardBySameBase,
CppStructNonStandardBySameBase2), "");
+ static_assert(!__is_layout_compatible(CppStructNonStandardBy2ndVirtBase,
CppStructNonStandardBy2ndVirtBase2), "");
+ static_assert(!__is_layout_compatible(CStruct, CStructWithQualifiers), "");
// FIXME: this is CWG1719
+ static_assert(__is_layout_compatible(CStruct, CStructNoUniqueAddress) ==
bool(__has_cpp_attribute(no_unique_address)), ""); // FIXME: this is CWG2759
+ static_assert(__is_layout_compatible(CStructNoUniqueAddress,
CStructNoUniqueAddress2) == bool(__has_cpp_attribute(no_unique_address)), "");
// FIXME: this is CWG2759
+ static_assert(__is_layout_compatible(CStruct, CStructAlignment), "");
+ static_assert(__is_layout_compatible(CStructIncomplete, CStructIncomplete),
"");
+ static_assert(!__is_layout_compatible(CStruct, CStructIncomplete), "");
+}
----------------
AaronBallman wrote:
> We don't issue any, as far as I can see. And I don't think we can when the
> types are the same, ignoring cv qualifiers:
That's a bug, see
https://eel.is/c++draft/tab:meta.rel#row-6-column-3-sentence-1: "T and U shall
be complete types, cv void, or arrays of unknown bound."
but also: https://eel.is/c++draft/tab:meta.rel#row-6-column-3-sentence-1and
http://eel.is/c++draft/class.mem#general-23 -- you can't test for layout
compatibility if the class type is not complete because you don't know the
members. So we should accept `void` but not `struct NeverDefined`.
https://github.com/llvm/llvm-project/pull/81506
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