Index: include/clang/CodeGen/CodeGenABITypes.h
===================================================================
--- include/clang/CodeGen/CodeGenABITypes.h
+++ include/clang/CodeGen/CodeGenABITypes.h
@@ -78,6 +78,10 @@
 
 llvm::Type *convertTypeForMemory(CodeGenModule &CGM, QualType T);
 
+// Returns a field number for a struct suitable for GEP'ing
+unsigned getFieldNumber(CodeGenModule &CGM,
+                        const RecordDecl *RD, const FieldDecl *FD);
+
 }  // end namespace CodeGen
 }  // end namespace clang
 
Index: lib/CodeGen/CodeGenABITypes.cpp
===================================================================
--- lib/CodeGen/CodeGenABITypes.cpp
+++ lib/CodeGen/CodeGenABITypes.cpp
@@ -17,6 +17,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/CodeGen/CodeGenABITypes.h"
+#include "CGRecordLayout.h"
 #include "CodeGenModule.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
 #include "clang/Frontend/CodeGenOptions.h"
@@ -80,3 +81,8 @@
 CodeGen::convertTypeForMemory(CodeGenModule &CGM, QualType T) {
   return CGM.getTypes().ConvertTypeForMem(T);
 }
+
+unsigned CodeGen::getFieldNumber(CodeGenModule &CGM,
+                                 const RecordDecl *RD, const FieldDecl *FD) {
+  return CGM.getTypes().getCGRecordLayout(RD).getLLVMFieldNo(FD);
+}