Initial support for struct-path aware TBAA.

Added TBAABaseType and TBAAOffset in LValue. These two fields are initialized to
the actual type and 0, and are updated in EmitLValueForField.
Path-aware TBAA tags are enabled for EmitLoadOfScalar and EmitStoreOfScalar.
Added command line option -struct-path-tbaa.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178797 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 6d85a88..c518a55 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -227,6 +227,20 @@
   return TBAA->getTBAAStructInfo(QTy);
 }
 
+llvm::MDNode *CodeGenModule::getTBAAStructTypeInfo(QualType QTy) {
+  if (!TBAA)
+    return 0;
+  return TBAA->getTBAAStructTypeInfo(QTy);
+}
+
+llvm::MDNode *CodeGenModule::getTBAAStructTagInfo(QualType BaseTy,
+                                                  llvm::MDNode *AccessN,
+                                                  uint64_t O) {
+  if (!TBAA)
+    return 0;
+  return TBAA->getTBAAStructTagInfo(BaseTy, AccessN, O);
+}
+
 void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst,
                                         llvm::MDNode *TBAAInfo) {
   Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo);