--- a/src/cpu/x86/vm/registerMap_x86.hpp	Tue Apr 14 17:26:29 2015 -0700
+++ b/src/cpu/x86/vm/registerMap_x86.hpp	Tue Apr 14 22:20:07 2015 -0700
@@ -31,11 +31,7 @@
  private:
   // This is the hook for finding a register in an "well-known" location,
   // such as a register block of a predetermined format.
-  // Since there is none, we just return NULL.
-  // See registerMap_sparc.hpp for an example of grabbing registers
-  // from register save areas of a standard layout.
-   address pd_location(VMReg reg) const {return NULL;}
-
+  address pd_location(VMReg reg) const;
   // no PD state to clear or copy:
   void pd_clear() {}
   void pd_initialize() {}