Further improve deopt reason output.

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 190 matching lines @@
                          LInstruction* instr,
                          RDIState rdi_state);
 
   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 = NULL);
+  void DeoptimizeIf(Condition cc, LInstruction* instr, const char* detail);
 
   bool DeoptEveryNTimes() {
     return FLAG_deopt_every_n_times != 0 && !info()->IsStub();
   }
 
   void AddToTranslation(LEnvironment* environment,
                         Translation* translation,
                         LOperand* op,
                         bool is_tagged,
                         bool is_uint32,
@@ skipping 172 matching lines @@
   Label entry_;
   Label exit_;
   Label done_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_LITHIUM_CODEGEN_X64_H_