Emit standard-library RTTI with external linkage, not weak_odr.
Apply hidden visibility to most RTTI; libstdc++ does not rely on exact
pointer equality for the type info (just the type info names). Apply
the same optimization to RTTI that we do to vtables.
Fixes PR5962.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110192 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 63d7913..d2be5af 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -216,6 +216,57 @@
}
}
+/// Set the symbol visibility of type information (vtable and RTTI)
+/// associated with the given type.
+void CodeGenModule::setTypeVisibility(llvm::GlobalValue *GV,
+ const CXXRecordDecl *RD,
+ bool IsForRTTI) const {
+ setGlobalVisibility(GV, RD);
+
+ // We want to drop the visibility to hidden for weak type symbols.
+ // This isn't possible if there might be unresolved references
+ // elsewhere that rely on this symbol being visible.
+
+ // Preconditions.
+ if (GV->getLinkage() != llvm::GlobalVariable::WeakODRLinkage ||
+ GV->getVisibility() != llvm::GlobalVariable::DefaultVisibility)
+ return;
+
+ // Don't override an explicit visibility attribute.
+ if (RD->hasAttr<VisibilityAttr>())
+ return;
+
+ switch (RD->getTemplateSpecializationKind()) {
+ // We have to disable the optimization if this is an EI definition
+ // because there might be EI declarations in other shared objects.
+ case TSK_ExplicitInstantiationDefinition:
+ case TSK_ExplicitInstantiationDeclaration:
+ return;
+
+ // Every use of a non-template or explicitly-specialized class's
+ // type information has to emit it.
+ case TSK_ExplicitSpecialization:
+ case TSK_Undeclared:
+ break;
+
+ // Implicit instantiations can ignore the possibility of an
+ // explicit instantiation declaration because there necessarily
+ // must be an EI definition somewhere with default visibility.
+ case TSK_ImplicitInstantiation:
+ break;
+ }
+
+ // If there's a key function, there may be translation units
+ // that don't have the key function's definition. But ignore
+ // this if we're emitting RTTI under -fno-rtti.
+ if (!IsForRTTI || Features.RTTI)
+ if (Context.getKeyFunction(RD))
+ return;
+
+ // Otherwise, drop the visibility to hidden.
+ GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
+}
+
llvm::StringRef CodeGenModule::getMangledName(GlobalDecl GD) {
const NamedDecl *ND = cast<NamedDecl>(GD.getDecl());