[msan] Fix bad interaction between with-calls mode and chained origin tracking.

Origin history should only be recorded for uninitialized values, because it is
meaningless otherwise. This change moves __msan_chain_origin to the runtime
library side and makes it conditional on the corresponding shadow value.

Previous code was correct, but _very_ inefficient.

llvm-svn: 211700

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 75c56c2d430..4ca03238071 100644
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -569,7 +569,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
             ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
         IRB.CreateCall3(Fn, ConvertedShadow2,
                         IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
-                        updateOrigin(Origin, IRB));
+                        Origin);
       } else {
         Value *Cmp = IRB.CreateICmpNE(
             ConvertedShadow, getCleanShadow(ConvertedShadow), "_mscmp");