commit 8cb4a070d491ddd671b049110cc8d0accb08b905
author Kostya Serebryany <kcc@google.com> Mon Mar 26 17:03:51 2012 +0000
committer Kostya Serebryany <kcc@google.com> Mon Mar 26 17:03:51 2012 +0000
tree 069fdc3e8e7959280024f5ce210b4e2be3cd831a
parent 1eb18afd931f626713c066ede0707ceb522fa061

add tbaa metadata to vtable pointer loads/stores

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153447 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGClass.cpp

diff --git a/lib/CodeGen/CGClass.cpp b/lib/CodeGen/CGClass.cpp
index ee79c39..b452c1b 100644
--- a/lib/CodeGen/CGClass.cpp
+++ b/lib/CodeGen/CGClass.cpp
@@ -1514,7 +1514,8 @@
   llvm::Type *AddressPointPtrTy =
     VTableAddressPoint->getType()->getPointerTo();
   VTableField = Builder.CreateBitCast(VTableField, AddressPointPtrTy);
-  Builder.CreateStore(VTableAddressPoint, VTableField);
+  llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
+  CGM.DecorateInstruction(Store, CGM.getTBAAInfoForVTablePtr());
 }
 
 void
@@ -1597,7 +1598,9 @@
 llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
                                            llvm::Type *Ty) {
   llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo());
-  return Builder.CreateLoad(VTablePtrSrc, "vtable");
+  llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable");
+  CGM.DecorateInstruction(VTable, CGM.getTBAAInfoForVTablePtr());
+  return VTable;
 }
 
 static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) {

lib/CodeGen/CodeGenModule.cpp

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 1c8f5f6..cc19d95 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -182,6 +182,12 @@
   return TBAA->getTBAAInfo(QTy);
 }
 
+llvm::MDNode *CodeGenModule::getTBAAInfoForVTablePtr() {
+  if (!TBAA)
+    return 0;
+  return TBAA->getTBAAInfoForVTablePtr();
+}
+
 void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst,
                                         llvm::MDNode *TBAAInfo) {
   Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo);

lib/CodeGen/CodeGenModule.h

diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 8f9cdcd..5719afb 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -448,6 +448,7 @@
   bool shouldUseTBAA() const { return TBAA != 0; }
 
   llvm::MDNode *getTBAAInfo(QualType QTy);
+  llvm::MDNode *getTBAAInfoForVTablePtr();
 
   bool isTypeConstant(QualType QTy, bool ExcludeCtorDtor);
 

lib/CodeGen/CodeGenTBAA.cpp

diff --git a/lib/CodeGen/CodeGenTBAA.cpp b/lib/CodeGen/CodeGenTBAA.cpp
index 148081e..9ee3f1d 100644
--- a/lib/CodeGen/CodeGenTBAA.cpp
+++ b/lib/CodeGen/CodeGenTBAA.cpp
@@ -179,3 +179,7 @@
   // For now, handle any other kind of type conservatively.
   return MetadataCache[Ty] = getChar();
 }
+
+llvm::MDNode *CodeGenTBAA::getTBAAInfoForVTablePtr() {
+  return getTBAAInfoForNamedType("vtable pointer", getRoot());
+}

lib/CodeGen/CodeGenTBAA.h

diff --git a/lib/CodeGen/CodeGenTBAA.h b/lib/CodeGen/CodeGenTBAA.h
index 9fe51fb..8e08498 100644
--- a/lib/CodeGen/CodeGenTBAA.h
+++ b/lib/CodeGen/CodeGenTBAA.h
@@ -68,6 +68,10 @@
   /// getTBAAInfo - Get the TBAA MDNode to be used for a dereference
   /// of the given type.
   llvm::MDNode *getTBAAInfo(QualType QTy);
+
+  /// getTBAAInfoForVTablePtr - Get the TBAA MDNode to be used for a
+  /// dereference of a vtable pointer.
+  llvm::MDNode *getTBAAInfoForVTablePtr();
 };
 
 }  // end namespace CodeGen