Probe the symbol table for two character strings in native code...

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
===================================================================
--- src/ia32/macro-assembler-ia32.h	(revision 3833)
+++ src/ia32/macro-assembler-ia32.h	(working copy)
@@ -425,6 +425,13 @@
   // ---------------------------------------------------------------------------
   // String utilities.
 
+  // Check whether the instance type represents a flat ascii string. Jump to the
+  // label if not. If the instance type can be scratched specify same register
+  // for both instance type and scratch.
+  void JumpIfInstanceTypeIsNotSequentialAscii(Register instance_type,
+                                              Register scratch,
+                                              Label *on_not_flat_ascii_string);
+
   // Checks if both objects are sequential ASCII strings, and jumps to label
   // if either is not.
   void JumpIfNotBothSequentialAsciiStrings(Register object1,