Set a fixed scratch register for ARM code generation...

src/arm/lithium-codegen-arm.h

 // Copyright 2010 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 85 matching lines @@
   bool is_unused() const { return status_ == UNUSED; }
   bool is_generating() const { return status_ == GENERATING; }
   bool is_done() const { return status_ == DONE; }
   bool is_aborted() const { return status_ == ABORTED; }
 
   LChunk* chunk() const { return chunk_; }
   Scope* scope() const { return scope_; }
   HGraph* graph() const { return chunk_->graph(); }
   MacroAssembler* masm() const { return masm_; }
 
+  Register scratch0() { return r9; }
+
   int GetNextEmittedBlock(int block);
   LInstruction* GetNextInstruction();
 
   void EmitClassOfTest(Label* if_true,
                        Label* if_false,
                        Handle<String> class_name,
                        Register input,
                        Register temporary,
                        Register temporary2);
 
@@ skipping 149 matching lines @@
  private:
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_CODEGEN_ARM_H_