[llvm-commits] [llvm] r173153 - in /llvm/trunk: lib/Transforms/Instrumentation/MemorySanitizer.cpp test/Instrumentation/MemorySanitizer/msan_basic.ll

[Evgeniy Stepanov]

Author: eugenis
Date: Tue Jan 22 06:30:52 2013
New Revision: 173153

URL: http://llvm.org/viewvc/llvm-project?rev=173153&view=rev
Log:
[msan] Do not insert check on volatile store.

Volatile bitfields can cause valid stores of uninitialized bits.

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
    llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp?rev=173153&r1=173152&r2=173153&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp Tue Jan 22 06:30:52 2013
@@ -451,9 +451,7 @@
         IRB.CreateAlignedStore(Shadow, ShadowPtr, I.getAlignment());
       DEBUG(dbgs() << "  STORE: " << *NewSI << "\n");
       (void)NewSI;
-      // If the store is volatile, add a check.
-      if (I.isVolatile())
-        insertCheck(Val, &I);
+
       if (ClCheckAccessAddress)
         insertCheck(Addr, &I);
 
@@ -847,7 +845,6 @@
   ///
   /// Stores the corresponding shadow and (optionally) origin.
   /// Optionally, checks that the store address is fully defined.
-  /// Volatile stores check that the value being stored is fully defined.
   void visitStoreInst(StoreInst &I) {
     StoreList.push_back(&I);
   }

Modified: llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll?rev=173153&r1=173152&r2=173153&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll (original)
+++ llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll Tue Jan 22 06:30:52 2013
@@ -563,3 +563,17 @@
 ; CHECK: @VACopy
 ; CHECK: call void @llvm.memset.p0i8.i64({{.*}}, i8 0, i64 24, i32 8, i1 false)
 ; CHECK: ret void
+
+
+; Test handling of volatile stores.
+; Check that MemorySanitizer does not add a check of the value being stored.
+
+define void @VolatileStore(i32* nocapture %p, i32 %x) nounwind uwtable {
+entry:
+  store volatile i32 %x, i32* %p, align 4
+  ret void
+}
+
+; CHECK: @VolatileStore
+; CHECK-NOT: @__msan_warning
+; CHECK: ret void