commit 52eb699220aa00696b5c4a1a67141a8bcc8a4e68
author Kostya Serebryany <kcc@google.com> Mon Mar 26 17:35:03 2012 +0000
committer Kostya Serebryany <kcc@google.com> Mon Mar 26 17:35:03 2012 +0000
tree 2d09229fd220e94e71c7f4a07e752fff19c474ef
parent be3f051c49699a86d526833d7dbe95645680a340

[tsan] treat vtable pointer updates in a special way (requires tbaa); fix a bug (forgot to return true after instrumenting); make sure the tsan tests are run

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153448 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Instrumentation/ThreadSanitizer.cpp

diff --git a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index 85fda30..b774211 100644
--- a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -27,11 +27,14 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/Function.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Metadata.h"
 #include "llvm/Module.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/IRBuilder.h"
 #include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Transforms/Instrumentation.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
@@ -61,6 +64,7 @@
   static const size_t kNumberOfAccessSizes = 5;
   Value *TsanRead[kNumberOfAccessSizes];
   Value *TsanWrite[kNumberOfAccessSizes];
+  Value *TsanVptrUpdate;
 };
 }  // namespace
 
@@ -105,6 +109,9 @@
     TsanWrite[i] = M.getOrInsertFunction(WriteName, IRB.getVoidTy(),
                                          IRB.getInt8PtrTy(), NULL);
   }
+  TsanVptrUpdate = M.getOrInsertFunction("__tsan_vptr_update", IRB.getVoidTy(),
+                                         IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
+                                         NULL);
   return true;
 }
 
@@ -151,10 +158,21 @@
       IRBuilder<> IRBRet(RetVec[i]);
       IRBRet.CreateCall(TsanFuncExit);
     }
+    Res = true;
   }
   return Res;
 }
 
+static bool isVtableAccess(Instruction *I) {
+  if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa)) {
+    if (Tag->getNumOperands() < 1) return false;
+    if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
+      if (Tag1->getString() == "vtable pointer") return true;
+    }
+  }
+  return false;
+}
+
 bool ThreadSanitizer::instrumentLoadOrStore(Instruction *I) {
   IRBuilder<> IRB(I);
   bool IsWrite = isa<StoreInst>(*I);
@@ -170,6 +188,13 @@
     // Ignore all unusual sizes.
     return false;
   }
+  if (IsWrite && isVtableAccess(I)) {
+    Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
+    IRB.CreateCall2(TsanVptrUpdate,
+                    IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
+                    IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy()));
+    return true;
+  }
   size_t Idx = CountTrailingZeros_32(TypeSize / 8);
   assert(Idx < kNumberOfAccessSizes);
   Value *OnAccessFunc = IsWrite ? TsanWrite[Idx] : TsanRead[Idx];