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[clang-cl] Fix PR38934: failing to dllexport class template member w/ explicit instantiation and PCH 

The code in ASTContext::DeclMustBeEmitted was supposed to handle this,
but didn't take into account that synthesized members such as operator=
might not get marked as template specializations, because they're
synthesized on the instantiation directly when handling the class-level
dllexport attribute.

llvm-svn: 342240
This commit is contained in:
Hans Wennborg 2018-09-14 15:18:30 +00:00
parent c0b474f67a
commit b51a70396e
2 changed files with 20 additions and 0 deletions
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8
clang/lib/AST/ASTContext.cpp
View File

@ -9724,6 +9724,14 @@ bool ASTContext::DeclMustBeEmitted(const Decl *D) {
cast<FunctionDecl>(D)->getTemplateSpecializationKind() ==
TSK_ExplicitInstantiationDefinition;
// Implicit member function definitions, such as operator= might not be
// marked as template specializations, since they're not coming from a
// template but synthesized directly on the class.
IsExpInstDef |=
isa<CXXMethodDecl>(D) &&
cast<CXXMethodDecl>(D)->getParent()->getTemplateSpecializationKind() ==
TSK_ExplicitInstantiationDefinition;
if (getExternalSource()->DeclIsFromPCHWithObjectFile(D) && !IsExpInstDef)
return false;
}

12
clang/test/CodeGen/pch-dllexport.cpp
View File

@ -57,6 +57,13 @@ extern template void explicitInstantiationDefAfterDecl<int>(int);
template <typename T> T __declspec(dllexport) variableTemplate;
extern template int variableTemplate<int>;
namespace pr38934 {
template <typename T> struct S {};
extern template struct S<int>;
// The use here causes the S<int>::operator= decl to go into the PCH.
inline void use(S<int> *a, S<int> *b) { *a = *b; };
}
#else
void use() {
@ -81,4 +88,9 @@ template void __declspec(dllexport) explicitInstantiationDefAfterDecl<int>(int);
template int __declspec(dllexport) variableTemplate<int>;
// PCHWITHOBJVARS: @"??$variableTemplate@H@@3HA" = weak_odr dso_local dllexport global
// PR38934: Make sure S<int>::operator= gets emitted. While it itself isn't a
// template specialization, its parent is.
template struct __declspec(dllexport) pr38934::S<int>;
// PCHWITHOBJ: define weak_odr dso_local dllexport x86_thiscallcc dereferenceable(1) %"struct.pr38934::S"* @"??4?$S@H@pr38934@@QAEAAU01@ABU01@@Z"
#endif