[llvm] r196079 - [tsan] fix instrumentation of vector vptr updates (https://code.google.com/p/thread-sanitizer/issues/detail?id=43)

[Kostya Serebryany]

Author: kcc
Date: Mon Dec  2 02:07:15 2013
New Revision: 196079

URL: http://llvm.org/viewvc/llvm-project?rev=196079&view=rev
Log:
[tsan] fix instrumentation of vector vptr updates (https://code.google.com/p/thread-sanitizer/issues/detail?id=43)

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
    llvm/trunk/test/Instrumentation/ThreadSanitizer/vptr_update.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp?rev=196079&r1=196078&r2=196079&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp Mon Dec  2 02:07:15 2013
@@ -402,13 +402,16 @@ bool ThreadSanitizer::instrumentLoadOrSt
   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;
   }

Modified: llvm/trunk/test/Instrumentation/ThreadSanitizer/vptr_update.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/ThreadSanitizer/vptr_update.ll?rev=196079&r1=196078&r2=196079&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/ThreadSanitizer/vptr_update.ll (original)
+++ llvm/trunk/test/Instrumentation/ThreadSanitizer/vptr_update.ll Mon Dec  2 02:07:15 2013
@@ -4,10 +4,27 @@ target datalayout = "e-p:64:64:64-i1:8:8
 
 define void @Foo(i8** nocapture %a, i8* %b) nounwind uwtable sanitize_thread {
 entry:
+; CHECK-LABEL: @Foo
 ; CHECK: call void @__tsan_vptr_update
+; CHECK: ret void
   store i8* %b, i8** %a, align 8, !tbaa !0
   ret void
 }
+
+declare i32 @Func1()
+declare i32 @Func2()
+
+; Test that we properly handle vector stores marked as vtable updates.
+define void @VectorVptrUpdate(<2 x i8*>* nocapture %a, i8* %b) nounwind uwtable sanitize_thread {
+entry:
+; CHECK-LABEL: @VectorVptrUpdate
+; CHECK: call void @__tsan_vptr_update{{.*}}Func1
+; CHECK-NOT: call void @__tsan_vptr_update
+; CHECK: ret void
+  store <2 x i8 *> <i8* bitcast(i32 ()* @Func1 to i8 *), i8* bitcast(i32 ()* @Func2 to i8 *)>,  <2 x i8 *>* %a, align 8, !tbaa !0
+  ret void
+}
+
 !0 = metadata !{metadata !2, metadata !2, i64 0}
 !1 = metadata !{metadata !"Simple C/C++ TBAA", null}
 !2 = metadata !{metadata !"vtable pointer", metadata !1}