[CodeGen] EmitLoadOfPointer() 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

LValue CodeGenFunction::EmitLoadOfReferenceLValue(Address RefAddr,
   LValueBaseInfo BaseInfo;
   Address Addr = EmitLoadOfReference(RefAddr, RefTy, &BaseInfo);
   return MakeAddrLValue(Addr, RefTy->getPointeeType(), BaseInfo,
                         CGM.getTBAAAccessInfo(RefTy->getPointeeType()));
 }
 
 Address CodeGenFunction::EmitLoadOfPointer(Address Ptr,
                                            const PointerType *PtrTy,
-                                           LValueBaseInfo *BaseInfo) {
+                                           LValueBaseInfo *BaseInfo,
+                                           TBAAAccessInfo *TBAAInfo) {
+  if (TBAAInfo)
+    *TBAAInfo = CGM.getTBAAAccessInfo(PtrTy->getPointeeType());
+
   llvm::Value *Addr = Builder.CreateLoad(Ptr);
   return Address(Addr, getNaturalTypeAlignment(PtrTy->getPointeeType(),
                                                BaseInfo,
                                                /*forPointeeType=*/true));
 }
 
 LValue CodeGenFunction::EmitLoadOfPointerLValue(Address PtrAddr,
                                                 const PointerType *PtrTy) {
   LValueBaseInfo BaseInfo;
-  Address Addr = EmitLoadOfPointer(PtrAddr, PtrTy, &BaseInfo);
-  return MakeAddrLValue(Addr, PtrTy->getPointeeType(), BaseInfo,
-                        CGM.getTBAAAccessInfo(PtrTy->getPointeeType()));
+  TBAAAccessInfo TBAAInfo;
+  Address Addr = EmitLoadOfPointer(PtrAddr, PtrTy, &BaseInfo, &TBAAInfo);
+  return MakeAddrLValue(Addr, PtrTy->getPointeeType(), BaseInfo, TBAAInfo);
 }
 
 static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
                                       const Expr *E, const VarDecl *VD) {
   QualType T = E->getType();
 
   // If it's thread_local, emit a call to its wrapper function instead.
   if (VD->getTLSKind() == VarDecl::TLS_Dynamic &&

CodeGen/CodeGenFunction.h

#endif
   CharUnits getNaturalPointeeTypeAlignment(QualType T,
                                            LValueBaseInfo *BaseInfo = nullptr);
 
   Address EmitLoadOfReference(Address Ref, const ReferenceType *RefTy,
                               LValueBaseInfo *BaseInfo = nullptr);
   LValue EmitLoadOfReferenceLValue(Address Ref, const ReferenceType *RefTy);
 
   Address EmitLoadOfPointer(Address Ptr, const PointerType *PtrTy,
-                            LValueBaseInfo *BaseInfo = nullptr);
+                            LValueBaseInfo *BaseInfo = nullptr,
+                            TBAAAccessInfo *TBAAInfo = nullptr);
   LValue EmitLoadOfPointerLValue(Address Ptr, const PointerType *PtrTy);
 
   /// CreateTempAlloca - This creates an alloca and inserts it into the entry
   /// block if \p ArraySize is nullptr, otherwise inserts it at the current
   /// insertion point of the builder. The caller is responsible for setting an
   /// appropriate alignment on
   /// the alloca.
   ///