Porting r10023 and r10054 to x64 (pointer cache for external strings).

src/ia32/codegen-ia32.h

Index: src/ia32/codegen-ia32.h
diff --git a/src/ia32/codegen-ia32.h b/src/ia32/codegen-ia32.h
index c85fa83e9e2762839ddcc7b3bab134429aa13443..f4ab0b50f64a854354b1d1c05c4d488351d01cbd 100644
--- a/src/ia32/codegen-ia32.h
+++ b/src/ia32/codegen-ia32.h
@@ -72,6 +72,22 @@ class CodeGenerator {
 };
 
 
+class StringCharLoadGenerator : public AllStatic {
+ public:
+  // Generates the code for handling different string types and loading the
+  // indexed character into |result|.  We expect |index| as untagged input and
+  // |result| as untagged output.
+  static void Generate(MacroAssembler* masm,
+                       Factory* factory,
+                       Register string,
+                       Register index,
+                       Register result,
+                       Label* call_runtime);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(StringCharLoadGenerator);
+};
+
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_CODEGEN_IA32_H_