Further improve deopt reason output.

src/deoptimizer.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_DEOPTIMIZER_H_
 #define V8_DEOPTIMIZER_H_
 
 #include "src/v8.h"
 
 #include "src/allocation.h"
@@ skipping 86 matching lines @@
     // This last bailout type is not really a bailout, but used by the
     // debugger to deoptimize stack frames to allow inspection.
     DEBUGGER
   };
 
   static const int kBailoutTypesWithCodeEntry = SOFT + 1;
 
   struct Reason {
     Reason(int r, const char* m, const char* d)
         : raw_position(r), mnemonic(m), detail(d) {}
+
+    bool operator==(const Reason& other) const {
+      return raw_position == other.raw_position &&
+             CStringEquals(mnemonic, other.mnemonic) &&
+             CStringEquals(detail, other.detail);
+    }
+
+    bool operator!=(const Reason& other) const { return !(*this == other); }
+
     int raw_position;
     const char* mnemonic;
     const char* detail;
   };
 
   struct JumpTableEntry : public ZoneObject {
     inline JumpTableEntry(Address entry, const Reason& the_reason,
                           Deoptimizer::BailoutType type, bool frame)
         : label(),
           address(entry),
           reason(the_reason),
           bailout_type(type),
           needs_frame(frame) {}
+
+    bool IsEquivalentTo(const JumpTableEntry& other) const {
+      return address == other.address && bailout_type == other.bailout_type &&
+             needs_frame == other.needs_frame &&
+             (!FLAG_trace_deopt || reason == other.reason);
+    }
+
     Label label;
     Address address;
     Reason reason;
     Deoptimizer::BailoutType bailout_type;
     bool needs_frame;
   };
 
   static bool TraceEnabledFor(BailoutType deopt_type,
                               StackFrame::Type frame_type);
   static const char* MessageFor(BailoutType type);
@@ skipping 835 matching lines @@
   Object** parameters_;
   Object** expression_stack_;
   int source_position_;
 
   friend class Deoptimizer;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEOPTIMIZER_H_