[msan] Fix "missing origin" in atomic store.

An atomic store always make the target location fully initialized (in the
current implementation). It should not store origin. Initialized memory can't
have meaningful origin, and, due to origin granularity (4 bytes) there is a
chance that this extra store would overwrite meaningfull origin for an adjacent
location.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228444 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 4109bfdc3046a357e3d0e240e91d58c73d33a22b..b475234a4a2e4cb8bc838dfaa091c9adfad0bd70 100644 (file)
--- a/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -702,7 +702,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
 
       if (SI.isAtomic()) SI.setOrdering(addReleaseOrdering(SI.getOrdering()));
 
-      if (MS.TrackOrigins)
+      if (MS.TrackOrigins && !SI.isAtomic())
         storeOrigin(IRB, Addr, Shadow, getOrigin(Val), SI.getAlignment(),
                     InstrumentWithCalls);
     }

diff --git a/test/Instrumentation/MemorySanitizer/atomics.ll b/test/Instrumentation/MemorySanitizer/atomics.ll
index c8f3b88815bba8d8c64e014cd2622b26d759437d..28736ad7902986270f725a45b3fd477c7434a930 100644 (file)
--- a/test/Instrumentation/MemorySanitizer/atomics.ll
+++ b/test/Instrumentation/MemorySanitizer/atomics.ll
@@ -1,4 +1,6 @@
 ; RUN: opt < %s -msan -msan-check-access-address=0 -S | FileCheck %s
+; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=1 -S | FileCheck %s
+; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=2 -S | FileCheck %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"