PPC: [crankshaft] Support ES6 tail call elimination.

src/crankshaft/ppc/lithium-codegen-ppc.h

 // Copyright 2014 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_PPC_LITHIUM_CODEGEN_PPC_H_
 #define V8_CRANKSHAFT_PPC_LITHIUM_CODEGEN_PPC_H_
 
 #include "src/ast/scopes.h"
 #include "src/crankshaft/lithium-codegen.h"
 #include "src/crankshaft/ppc/lithium-gap-resolver-ppc.h"
@@ skipping 176 matching lines @@
 
   void CallRuntime(Runtime::FunctionId id, LInstruction* instr) {
     const Runtime::Function* function = Runtime::FunctionForId(id);
     CallRuntime(function, function->nargs, instr);
   }
 
   void LoadContextFromDeferred(LOperand* context);
   void CallRuntimeFromDeferred(Runtime::FunctionId id, int argc,
                                LInstruction* instr, 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 r4.
   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);
 
   void RegisterEnvironmentForDeoptimization(LEnvironment* environment,
                                             Safepoint::DeoptMode mode);
   void DeoptimizeIf(Condition condition, LInstruction* instr,
                     Deoptimizer::DeoptReason deopt_reason,
                     Deoptimizer::BailoutType bailout_type, CRegister cr = cr7);
   void DeoptimizeIf(Condition condition, LInstruction* instr,
@@ skipping 138 matching lines @@
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
   int instruction_index_;
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CRANKSHAFT_PPC_LITHIUM_CODEGEN_PPC_H_