Emit vtables for an extern template class as available_externally, not as
linkonce_odr. Emit construction vtables as internal in this case, since the ABI
does not guarantee that they will be availble externally.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175330 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGVTables.cpp b/lib/CodeGen/CGVTables.cpp
index 6d40219..0c5d72f 100644
--- a/lib/CodeGen/CGVTables.cpp
+++ b/lib/CodeGen/CGVTables.cpp
@@ -686,6 +686,14 @@
llvm::ArrayType *ArrayType =
llvm::ArrayType::get(CGM.Int8PtrTy, VTLayout->getNumVTableComponents());
+ // Construction vtable symbols are not part of the Itanium ABI, so we cannot
+ // guarantee that they actually will be available externally. Instead, when
+ // emitting an available_externally VTT, we provide references to an internal
+ // linkage construction vtable. The ABI only requires complete-object vtables
+ // to be the same for all instances of a type, not construction vtables.
+ if (Linkage == llvm::GlobalVariable::AvailableExternallyLinkage)
+ Linkage = llvm::GlobalVariable::InternalLinkage;
+
// Create the variable that will hold the construction vtable.
llvm::GlobalVariable *VTable =
CGM.CreateOrReplaceCXXRuntimeVariable(Name, ArrayType, Linkage);
@@ -750,11 +758,8 @@
llvm::Function::InternalLinkage;
case TSK_ExplicitInstantiationDeclaration:
- // FIXME: Use available_externally linkage. However, this currently
- // breaks LLVM's build due to undefined symbols.
- // return llvm::GlobalVariable::AvailableExternallyLinkage;
return !Context.getLangOpts().AppleKext ?
- llvm::GlobalVariable::LinkOnceODRLinkage :
+ llvm::GlobalVariable::AvailableExternallyLinkage :
llvm::Function::InternalLinkage;
}
}
@@ -771,10 +776,7 @@
return llvm::GlobalVariable::LinkOnceODRLinkage;
case TSK_ExplicitInstantiationDeclaration:
- // FIXME: Use available_externally linkage. However, this currently
- // breaks LLVM's build due to undefined symbols.
- // return llvm::GlobalVariable::AvailableExternallyLinkage;
- return llvm::GlobalVariable::LinkOnceODRLinkage;
+ return llvm::GlobalVariable::AvailableExternallyLinkage;
case TSK_ExplicitInstantiationDefinition:
return llvm::GlobalVariable::WeakODRLinkage;