[Sema] Restrict explicit instantation definition dllexport
In the case where the template class itself is already `dllexport`, the
implicit instantiation will have already emitted all members. When we
check the explicit instantiation definition, the `Specialization` will
have inherited the `dllexport` attribute, so we'll attempt to emit all
members for a second time, which causes an assertion failure. Restrict
the exporting to when the `dllexport` attribute is newly introduced by
the explicit instantiation definition.
Fixes PR31608.
Differential Revision: https://reviews.llvm.org/D28590
llvm-svn: 291877
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 7edef70..8ad5b59 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -7789,6 +7789,7 @@
Specialization->setTemplateKeywordLoc(TemplateLoc);
Specialization->setBraceRange(SourceRange());
+ bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
if (Attr)
ProcessDeclAttributeList(S, Specialization, Attr);
@@ -7851,8 +7852,9 @@
// Fix a TSK_ImplicitInstantiation followed by a
// TSK_ExplicitInstantiationDefinition
- if (Old_TSK == TSK_ImplicitInstantiation &&
- Specialization->hasAttr<DLLExportAttr>() &&
+ bool NewlyDLLExported =
+ !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
+ if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
(Context.getTargetInfo().getCXXABI().isMicrosoft() ||
Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
// In the MS ABI, an explicit instantiation definition can add a dll