When doing a derived-to-base class through a virtual class, we don't have to get the vbase offset from the vtable if the derived class is marked final.

llvm-svn: 124523

1 files changed, 11 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index 2a92258b846..a7b8f659786 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -180,8 +180,17 @@ CodeGenFunction::GetAddressOfBaseClass(llvm::Value *Value,
 
   llvm::Value *VirtualOffset = 0;
 
-  if (VBase)
-    VirtualOffset = GetVirtualBaseClassOffset(Value, Derived, VBase);
+  if (VBase) {
+    if (Derived->hasAttr<FinalAttr>()) {
+      VirtualOffset = 0;
+
+      const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
+
+      uint64_t VBaseOffset = Layout.getVBaseClassOffsetInBits(VBase);
+      NonVirtualOffset += VBaseOffset / 8;
+    } else
+      VirtualOffset = GetVirtualBaseClassOffset(Value, Derived, VBase);
+  }
 
   // Apply the offsets.
   Value = ApplyNonVirtualAndVirtualOffset(*this, Value, NonVirtualOffset,