Fix potential overwriting of debug jumps of following code.

src/safepoint-table.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 202 matching lines @@
 
   // Get the offset of the emitted safepoint table in the code.
   unsigned GetCodeOffset() const;
 
   // Define a new safepoint for the current position in the body.
   Safepoint DefineSafepoint(Assembler* assembler,
                             Safepoint::Kind kind,
                             int arguments,
                             int deoptimization_index);
 
-  // Update the last safepoint with the size of the code generated for the gap
-  // following it.
+  // Update the last safepoint with the size of the code generated until the
+  // end of the gap following it.
   void SetPcAfterGap(int pc) {
     ASSERT(!deoptimization_info_.is_empty());
     int index = deoptimization_info_.length() - 1;
     deoptimization_info_[index].pc_after_gap = pc;
   }
 
   // Emit the safepoint table after the body. The number of bits per
   // entry must be enough to hold all the pointer indexes.
   void Emit(Assembler* assembler, int bits_per_entry);
 
+  // Count the number of deoptimization points where the next
+  // following deoptimization point comes less than limit bytes
+  // after the end of this point's gap.
+  int CountShortDeoptimizationIntervals(unsigned limit);
+
  private:
   struct DeoptimizationInfo {
     unsigned pc;
     unsigned deoptimization_index;
     unsigned pc_after_gap;
     unsigned arguments;
     bool has_doubles;
   };
 
   uint32_t EncodeExceptPC(const DeoptimizationInfo& info);
 
   ZoneList<DeoptimizationInfo> deoptimization_info_;
   ZoneList<ZoneList<int>*> indexes_;
   ZoneList<ZoneList<int>*> registers_;
 
+  unsigned offset_;
   bool emitted_;
-  unsigned offset_;
 
   DISALLOW_COPY_AND_ASSIGN(SafepointTableBuilder);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SAFEPOINT_TABLE_H_