[opaque pointer types] Cleanup CGBuilder's Create*GEP.

The various EltSize, Offset, DataLayout, and StructLayout arguments
are all computable from the Address's element type and the DataLayout
which the CGBuilder already has access to.

After having previously asserted that the computed values are the same
as those passed in, now remove the redundant arguments from
CGBuilder's Create*GEP functions.

Differential Revision: https://reviews.llvm.org/D57767

llvm-svn: 353629
diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 520d860..b045ac7 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -2008,9 +2008,8 @@
                          "objc_super");
   llvm::Value *ReceiverAsObject =
     CGF.Builder.CreateBitCast(Receiver, ObjCTypes.ObjectPtrTy);
-  CGF.Builder.CreateStore(
-      ReceiverAsObject,
-      CGF.Builder.CreateStructGEP(ObjCSuper, 0, CharUnits::Zero()));
+  CGF.Builder.CreateStore(ReceiverAsObject,
+                          CGF.Builder.CreateStructGEP(ObjCSuper, 0));
 
   // If this is a class message the metaclass is passed as the target.
   llvm::Value *Target;
@@ -2045,8 +2044,7 @@
   llvm::Type *ClassTy =
     CGM.getTypes().ConvertType(CGF.getContext().getObjCClassType());
   Target = CGF.Builder.CreateBitCast(Target, ClassTy);
-  CGF.Builder.CreateStore(Target,
-          CGF.Builder.CreateStructGEP(ObjCSuper, 1, CGF.getPointerSize()));
+  CGF.Builder.CreateStore(Target, CGF.Builder.CreateStructGEP(ObjCSuper, 1));
   return EmitMessageSend(CGF, Return, ResultType,
                          EmitSelector(CGF, Sel),
                          ObjCSuper.getPointer(), ObjCTypes.SuperPtrCTy,
@@ -7156,8 +7154,7 @@
   args[1].setRValue(RValue::get(mref.getPointer()));
 
   // Load the function to call from the message ref table.
-  Address calleeAddr =
-      CGF.Builder.CreateStructGEP(mref, 0, CharUnits::Zero());
+  Address calleeAddr = CGF.Builder.CreateStructGEP(mref, 0);
   llvm::Value *calleePtr = CGF.Builder.CreateLoad(calleeAddr, "msgSend_fn");
 
   calleePtr = CGF.Builder.CreateBitCast(calleePtr, MSI.MessengerType);
@@ -7354,9 +7351,8 @@
 
   llvm::Value *ReceiverAsObject =
     CGF.Builder.CreateBitCast(Receiver, ObjCTypes.ObjectPtrTy);
-  CGF.Builder.CreateStore(
-      ReceiverAsObject,
-      CGF.Builder.CreateStructGEP(ObjCSuper, 0, CharUnits::Zero()));
+  CGF.Builder.CreateStore(ReceiverAsObject,
+                          CGF.Builder.CreateStructGEP(ObjCSuper, 0));
 
   // If this is a class message the metaclass is passed as the target.
   llvm::Value *Target;
@@ -7370,8 +7366,7 @@
   llvm::Type *ClassTy =
     CGM.getTypes().ConvertType(CGF.getContext().getObjCClassType());
   Target = CGF.Builder.CreateBitCast(Target, ClassTy);
-  CGF.Builder.CreateStore(
-      Target, CGF.Builder.CreateStructGEP(ObjCSuper, 1, CGF.getPointerSize()));
+  CGF.Builder.CreateStore(Target, CGF.Builder.CreateStructGEP(ObjCSuper, 1));
 
   return (isVTableDispatchedSelector(Sel))
     ? EmitVTableMessageSend(CGF, Return, ResultType, Sel,