[crankshaft] Support ES6 tail call elimination.

src/crankshaft/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_CRANKSHAFT_X64_LITHIUM_CODEGEN_X64_H_
 #define V8_CRANKSHAFT_X64_LITHIUM_CODEGEN_X64_H_
 
 
 #include "src/ast/scopes.h"
 #include "src/base/logging.h"
@@ skipping 174 matching lines @@
     CallRuntime(function, function->nargs, instr);
   }
 
   void CallRuntimeFromDeferred(Runtime::FunctionId id,
                                int argc,
                                LInstruction* instr,
                                LOperand* context);
 
   void LoadContextFromDeferred(LOperand* context);
 
+  void PrepareForTailCall(const ParameterCount& actual, Register scratch1,
+                          Register scratch2, Register scratch3);
+
   // 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);
+                         bool is_tail_call, LInstruction* instr);
 
   void RecordSafepointWithLazyDeopt(LInstruction* instr,
                                     SafepointMode safepoint_mode,
                                     int argc);
   void RegisterEnvironmentForDeoptimization(LEnvironment* environment,
                                             Safepoint::DeoptMode mode);
   void DeoptimizeIf(Condition cc, LInstruction* instr,
                     Deoptimizer::DeoptReason deopt_reason,
                     Deoptimizer::BailoutType bailout_type);
   void DeoptimizeIf(Condition cc, LInstruction* instr,
@@ skipping 168 matching lines @@
   Label exit_;
   Label done_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CRANKSHAFT_X64_LITHIUM_CODEGEN_X64_H_