LCodeGen::CallKnownFunction gets the function in register.

src/x64/lithium-codegen-x64.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_X64_LITHIUM_CODEGEN_X64_H_
 #define V8_X64_LITHIUM_CODEGEN_X64_H_
 
 #include "src/x64/lithium-x64.h"
 
 #include "src/base/logging.h"
@@ skipping 170 matching lines @@
     CallRuntime(function, num_arguments, instr);
   }
 
   void CallRuntimeFromDeferred(Runtime::FunctionId id,
                                int argc,
                                LInstruction* instr,
                                LOperand* context);
 
   void LoadContextFromDeferred(LOperand* context);
 
-  enum RDIState {
-    RDI_UNINITIALIZED,
-    RDI_CONTAINS_TARGET
-  };
-
   // Generate a direct call to a known function.  Expects the function
   // to be in rdi.
   void CallKnownFunction(Handle<JSFunction> function,
-                         int formal_parameter_count,
-                         int arity,
-                         LInstruction* instr,
-                         RDIState rdi_state);
+                         int formal_parameter_count, int arity,
+                         LInstruction* instr);
 
   void RecordSafepointWithLazyDeopt(LInstruction* instr,
                                     SafepointMode safepoint_mode,
                                     int argc);
   void RegisterEnvironmentForDeoptimization(LEnvironment* environment,
                                             Safepoint::DeoptMode mode);
   void DeoptimizeIf(Condition cc, LInstruction* instr, const char* detail,
                     Deoptimizer::BailoutType bailout_type);
   void DeoptimizeIf(Condition cc, LInstruction* instr, const char* detail);
 
@@ skipping 181 matching lines @@
   Label entry_;
   Label exit_;
   Label done_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_LITHIUM_CODEGEN_X64_H_