TBAA: add isTBAAVtableAccess to MDNode so clients can call the function

instead of having its own implementation.

The implementation of isTBAAVtableAccess is in TypeBasedAliasAnalysis.cpp
since it is related to the format of TBAA metadata.

The path for struct-path tbaa will be exercised by
test/Instrumentation/ThreadSanitizer/read_from_global.ll, vptr_read.ll, and
vptr_update.ll when struct-path tbaa is on by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190216 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/IR/Metadata.h b/include/llvm/IR/Metadata.h
index acd84d7cc18eaa53b97bebdb44bd090b9c1ebecc..49eb89503147d8c21f6ca3f884c61ce5ec9eda7a 100644 (file)
--- a/include/llvm/IR/Metadata.h
+++ b/include/llvm/IR/Metadata.h
@@ -161,6 +161,9 @@ public:
     return V->getValueID() == MDNodeVal;
   }
 
+  /// Check whether MDNode is a vtable access.
+  bool isTBAAVtableAccess() const;
+
   /// Methods for metadata merging.
   static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
   static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);

diff --git a/lib/Analysis/TypeBasedAliasAnalysis.cpp b/lib/Analysis/TypeBasedAliasAnalysis.cpp
index bbf3c3a2a5ccad410a731d4d76e7e46358957040..ac3965feb88ecd0d58ed95446aea3fe895f32477 100644 (file)
--- a/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -458,6 +458,25 @@ TypeBasedAliasAnalysis::getModRefInfo(ImmutableCallSite CS1,
   return AliasAnalysis::getModRefInfo(CS1, CS2);
 }
 
+bool MDNode::isTBAAVtableAccess() const {
+  if (!EnableStructPathTBAA) {
+    if (getNumOperands() < 1) return false;
+    if (MDString *Tag1 = dyn_cast<MDString>(getOperand(0))) {
+      if (Tag1->getString() == "vtable pointer") return true;
+    }
+    return false;
+  }
+
+  // For struct-path aware TBAA, we use the access type of the tag.
+  if (getNumOperands() < 2) return false;
+  MDNode *Tag = cast_or_null<MDNode>(getOperand(1));
+  if (!Tag) return false;
+  if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
+    if (Tag1->getString() == "vtable pointer") return true;
+  }
+  return false;  
+}
+
 MDNode *MDNode::getMostGenericTBAA(MDNode *A, MDNode *B) {
   if (!A || !B)
     return NULL;

diff --git a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index e19ceba4d1669963e9af84fd53204e3be7d1e624..2c8a7c4118e47107f1bba36d200ead1b7db4782b 100644 (file)
--- a/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -240,12 +240,8 @@ bool ThreadSanitizer::doInitialization(Module &M) {
 }
 
 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;
-    }
-  }
+  if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa))
+    return Tag->isTBAAVtableAccess();
   return false;
 }