Detect simple tail calls

src/hydrogen-instructions.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_HYDROGEN_INSTRUCTIONS_H_
 #define V8_HYDROGEN_INSTRUCTIONS_H_
 
 #include <cstring>
 #include <iosfwd>
 
@@ skipping 2223 matching lines @@
         pass_argument_count_(pass_argument_count),
         has_stack_check_(has_stack_check) {
       SetOperandAt(0, function);
   }
 
   bool pass_argument_count_;
   bool has_stack_check_;
 };
 
 
-enum CallMode { NORMAL_CALL, TAIL_CALL };
-
-
 class HCallWithDescriptor final : public HInstruction {
  public:
   static HCallWithDescriptor* New(Isolate* isolate, Zone* zone, HValue* context,
                                   HValue* target, int argument_count,
                                   CallInterfaceDescriptor descriptor,
                                   const Vector<HValue*>& operands,
                                   CallMode call_mode = NORMAL_CALL) {
     DCHECK(operands.length() == descriptor.GetEnvironmentLength());
     HCallWithDescriptor* res = new (zone) HCallWithDescriptor(
         target, argument_count, descriptor, operands, call_mode, zone);
@@ skipping 5561 matching lines @@
 };
 
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_