ARM: Use ubfx and movw instructions to avoid a PC-relative load on

src/objects.h

Index: src/objects.h
===================================================================
--- src/objects.h	(revision 10578)
+++ src/objects.h	(working copy)
@@ -4593,6 +4593,9 @@
 
   inline FixedArray* unchecked_prototype_transitions();
 
+  // A map may not be smaller than 1 << kSizeBits bytes in size.
+  static const int kMapSizeBits = 5;
+
   static const int kProtoTransitionHeaderSize = 1;
   static const int kProtoTransitionNumberOfEntriesOffset = 0;
   static const int kProtoTransitionElementsPerEntry = 2;
@@ -8191,6 +8194,10 @@
   // Visit pointer embedded into a code object.
   virtual void VisitEmbeddedPointer(RelocInfo* rinfo);
 
+  // A signature of a map can be embedded in a code object.  At the
+  // moment a map can't move, so this is a read-only visitor.
+  virtual void VisitEmbeddedMapSignature(RelocInfo* rinfo);
+
   // Visits a contiguous arrays of external references (references to the C++
   // heap) in the half-open range [start, end). Any or all of the values
   // may be modified on return.