Restore saved caller FP registers on stub failure

src/arguments.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 271 matching lines @@
    */
   v8::Handle<v8::Value> Call(FunctionCallback f);
 
  private:
   internal::Object** argv_;
   int argc_;
   bool is_construct_call_;
 };
 
 
+double ClobberDoubleRegisters(double x1, double x2, double x3, double x4);
+
+
+#ifdef DEBUG
+#define CLOBBER_DOUBLE_REGISTERS() ClobberDoubleRegisters(1, 2, 3, 4);
+#else
+#define CLOBBER_DOUBLE_REGISTERS()
+#endif
+
+
 #define DECLARE_RUNTIME_FUNCTION(Type, Name)    \
 Type Name(int args_length, Object** args_object, Isolate* isolate)
 
 #define RUNTIME_FUNCTION(Type, Name)                                  \
 static Type __RT_impl_##Name(Arguments args, Isolate* isolate);       \
 Type Name(int args_length, Object** args_object, Isolate* isolate) {  \
+  CLOBBER_DOUBLE_REGISTERS();                                         \
   Arguments args(args_length, args_object);                           \
   return __RT_impl_##Name(args, isolate);                             \
 }                                                                     \
 static Type __RT_impl_##Name(Arguments args, Isolate* isolate)
 
 #define RUNTIME_ARGUMENTS(isolate, args) \
   args.length(), args.arguments(), isolate
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARGUMENTS_H_