[CodeGen] EmitLoadOfReference() to generate TBAA info along with LValue base info

[kosarev]

Summary

This patch should not bring in any functional changes. Prepared on top of D38733.

[rjmccall]

LGTM.

CodeGen/CGExpr.cpp

static LValue EmitThreadPrivateVarDeclLValue(
     llvm::Type *RealVarTy, SourceLocation Loc) {
   Addr = CGF.CGM.getOpenMPRuntime().getAddrOfThreadPrivate(CGF, VD, Addr, Loc);
   Addr = CGF.Builder.CreateElementBitCast(Addr, RealVarTy);
   return CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl);
 }
 
 Address CodeGenFunction::EmitLoadOfReference(Address Addr,
                                              const ReferenceType *RefTy,
-                                             LValueBaseInfo *BaseInfo) {
+                                             LValueBaseInfo *BaseInfo,
+                                             TBAAAccessInfo *TBAAInfo) {
+  if (TBAAInfo)
+    *TBAAInfo = CGM.getTBAAAccessInfo(RefTy->getPointeeType());
+
   llvm::Value *Ptr = Builder.CreateLoad(Addr);
   return Address(Ptr, getNaturalTypeAlignment(RefTy->getPointeeType(),
                                               BaseInfo, /*forPointee*/ true));
 }
 
 LValue CodeGenFunction::EmitLoadOfReferenceLValue(Address RefAddr,
                                                   const ReferenceType *RefTy) {
   LValueBaseInfo BaseInfo;
-  Address Addr = EmitLoadOfReference(RefAddr, RefTy, &BaseInfo);
-  return MakeAddrLValue(Addr, RefTy->getPointeeType(), BaseInfo,
-                        CGM.getTBAAAccessInfo(RefTy->getPointeeType()));
+  TBAAAccessInfo TBAAInfo;
+  Address Addr = EmitLoadOfReference(RefAddr, RefTy, &BaseInfo, &TBAAInfo);
+  return MakeAddrLValue(Addr, RefTy->getPointeeType(), BaseInfo, TBAAInfo);
 }
 
 Address CodeGenFunction::EmitLoadOfPointer(Address Ptr,
                                            const PointerType *PtrTy,
                                            LValueBaseInfo *BaseInfo,
                                            TBAAAccessInfo *TBAAInfo) {
   if (TBAAInfo)
     *TBAAInfo = CGM.getTBAAAccessInfo(PtrTy->getPointeeType());

CodeGen/CodeGenFunction.h

#endif
   LValue MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T);
   CharUnits getNaturalTypeAlignment(QualType T,
                                     LValueBaseInfo *BaseInfo = nullptr,
                                     bool forPointeeType = false);
   CharUnits getNaturalPointeeTypeAlignment(QualType T,
                                            LValueBaseInfo *BaseInfo = nullptr);
 
   Address EmitLoadOfReference(Address Ref, const ReferenceType *RefTy,
-                              LValueBaseInfo *BaseInfo = nullptr);
+                              LValueBaseInfo *BaseInfo = nullptr,
+                              TBAAAccessInfo *TBAAInfo = nullptr);
   LValue EmitLoadOfReferenceLValue(Address Ref, const ReferenceType *RefTy);
 
   Address EmitLoadOfPointer(Address Ptr, const PointerType *PtrTy,
                             LValueBaseInfo *BaseInfo = nullptr,
                             TBAAAccessInfo *TBAAInfo = nullptr);
   LValue EmitLoadOfPointerLValue(Address Ptr, const PointerType *PtrTy);
 
   /// CreateTempAlloca - This creates an alloca and inserts it into the entry