[llvm] r190216 - TBAA: add isTBAAVtableAccess to MDNode so clients can call the function

[Manman Ren]

Author: mren
Date: Fri Sep  6 17:47:05 2013
New Revision: 190216

URL: http://llvm.org/viewvc/llvm-project?rev=190216&view=rev
Log:
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.

Modified:
    llvm/trunk/include/llvm/IR/Metadata.h
    llvm/trunk/lib/Analysis/TypeBasedAliasAnalysis.cpp
    llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp

Modified: llvm/trunk/include/llvm/IR/Metadata.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Metadata.h?rev=190216&r1=190215&r2=190216&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/Metadata.h (original)
+++ llvm/trunk/include/llvm/IR/Metadata.h Fri Sep  6 17:47:05 2013
@@ -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);

Modified: llvm/trunk/lib/Analysis/TypeBasedAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/TypeBasedAliasAnalysis.cpp?rev=190216&r1=190215&r2=190216&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/TypeBasedAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/TypeBasedAliasAnalysis.cpp Fri Sep  6 17:47:05 2013
@@ -458,6 +458,25 @@ TypeBasedAliasAnalysis::getModRefInfo(Im
   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;

Modified: llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp?rev=190216&r1=190215&r2=190216&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp Fri Sep  6 17:47:05 2013
@@ -240,12 +240,8 @@ bool ThreadSanitizer::doInitialization(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;
 }