[tsan] fix instrumentation of vector vptr updates (https://code.google.com/p/thread-sanitizer/issues/detail?id=43)

llvm-svn: 196079

1 files changed, 7 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index 89fb746a5c4..baec1534e00 100644
--- a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -402,13 +402,16 @@ bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I) {
   if (IsWrite && isVtableAccess(I)) {
     DEBUG(dbgs() << "  VPTR : " << *I << "\n");
     Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
-    // StoredValue does not necessary have a pointer type.
-    if (isa<IntegerType>(StoredValue->getType()))
-      StoredValue = IRB.CreateIntToPtr(StoredValue, IRB.getInt8PtrTy());
+    // StoredValue may be a vector type if we are storing several vptrs at once.
+    // In this case, just take the first element of the vector since this is
+    // enough to find vptr races.
+    if (isa<VectorType>(StoredValue->getType()))
+      StoredValue = IRB.CreateExtractElement(
+          StoredValue, ConstantInt::get(IRB.getInt32Ty(), 0));
     // Call TsanVptrUpdate.
     IRB.CreateCall2(TsanVptrUpdate,
                     IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
-                    IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy()));
+                    IRB.CreateBitCast(StoredValue, IRB.getInt8PtrTy()));
     NumInstrumentedVtableWrites++;
     return true;
   }