When performing a ::delete of an object with a virtual destructor,

be sure to delete the complete object pointer, not the original
pointer.  This is necessary if the base being deleted is at a
non-zero offset in the complete object.  This is only required
for objects with virtual destructors because deleting an object
via a base-class subobject when the base does not have a virtual
destructor is undefined behavior.

Noticed while reviewing the last four years of cxx-abi-dev
activity.

llvm-svn: 164597

1 files changed, 7 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 3aa5e747812..7276440a47a 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -1382,8 +1382,14 @@ static void EmitObjectDelete(CodeGenFunction &CGF,
         if (UseGlobalDelete) {
           // If we're supposed to call the global delete, make sure we do so
           // even if the destructor throws.
+
+          // Derive the complete-object pointer, which is what we need
+          // to pass to the deallocation function.
+          llvm::Value *completePtr =
+            CGF.CGM.getCXXABI().adjustToCompleteObject(CGF, Ptr, ElementType);
+
           CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
-                                                    Ptr, OperatorDelete, 
+                                                    completePtr, OperatorDelete,
                                                     ElementType);
         }