3 files changed, 24 insertions, 6 deletions
diff --git a/include/llvm/IR/Metadata.h b/include/llvm/IR/Metadata.h
index acd84d7cc1..49eb895031 100644
--- a/include/llvm/IR/Metadata.h
+++ b/include/llvm/IR/Metadata.h
@@ -161,6 +161,9 @@ public:
     return V->getValueID() == MDNodeVal;
   }
 
+  /// Check whether MDNode is a vtable access.
+  bool isTBAAVtableAccess() const;
+
   /// Methods for metadata merging.
   static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
   static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
diff --git a/lib/Analysis/TypeBasedAliasAnalysis.cpp b/lib/Analysis/TypeBasedAliasAnalysis.cpp
index bbf3c3a2a5..ac3965feb8 100644
--- a/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -458,6 +458,25 @@ TypeBasedAliasAnalysis::getModRefInfo(ImmutableCallSite CS1,
   return AliasAnalysis::getModRefInfo(CS1, CS2);
 }
 
+bool MDNode::isTBAAVtableAccess() const {
+  if (!EnableStructPathTBAA) {
+    if (getNumOperands() < 1) return false;
+    if (MDString *Tag1 = dyn_cast<MDString>(getOperand(0))) {
+      if (Tag1->getString() == "vtable pointer") return true;
+    }
+    return false;
+  }
+
+  // For struct-path aware TBAA, we use the access type of the tag.
+  if (getNumOperands() < 2) return false;
+  MDNode *Tag = cast_or_null<MDNode>(getOperand(1));
+  if (!Tag) return false;
+  if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
+    if (Tag1->getString() == "vtable pointer") return true;
+  }
+  return false;  
+}
+
 MDNode *MDNode::getMostGenericTBAA(MDNode *A, MDNode *B) {
   if (!A || !B)
     return NULL;
diff --git a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index e19ceba4d1..2c8a7c4118 100644
--- a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -240,12 +240,8 @@ bool ThreadSanitizer::doInitialization(Module &M) {
 }
 
 static bool isVtableAccess(Instruction *I) {
-  if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa)) {
-    if (Tag->getNumOperands() < 1) return false;
-    if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
-      if (Tag1->getString() == "vtable pointer") return true;
-    }
-  }
+  if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa))
+    return Tag->isTBAAVtableAccess();
   return false;
 }