Improve debugger in MIPS simulator.

runtime/vm/simulator_mips.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Declares a Simulator for MIPS instructions if we are not generating a native
 // MIPS binary. This Simulator allows us to run and debug MIPS code generation
 // on regular desktop machines.
 // Dart calls into generated code by "calling" the InvokeDartCode stub,
 // which will start execution in the Simulator or forwards to the real entry
 // on a MIPS HW platform.
@@ skipping 72 matching lines @@
     }
   }
 
   bool test_fcsr_bit(uint32_t cc) {
     return fcsr_ & (1 << cc);
   }
 
   // Accessor to the internal simulator stack top.
   uword StackTop() const;
 
+  // Accessor to the instruction counter.
+  intptr_t get_icount() const { return icount_; }
+
   // The isolate's top_exit_frame_info refers to a Dart frame in the simulator
   // stack. The simulator's top_exit_frame_info refers to a C++ frame in the
   // native stack.
   uword top_exit_frame_info() const { return top_exit_frame_info_; }
   void set_top_exit_frame_info(uword value) { top_exit_frame_info_ = value; }
 
   // Call on program start.
   static void InitOnce();
 
   // Dart generally calls into generated code with 5 parameters. This is a
@@ skipping 67 matching lines @@
     return addr < 64*1024;
   }
   void HandleIllegalAccess(uword addr, Instr* instr);
 
   // Read and write memory.
   void UnalignedAccess(const char* msg, uword addr, Instr* instr);
 
   // Handles a legal instruction that the simulator does not implement.
   void UnimplementedInstruction(Instr* instr);
 
-  bool OverflowFrom(int32_t alu_out,
-                    int32_t left,
-                    int32_t right,
-                    bool addition);
-
   void set_pc(uword value) { pc_ = value; }
 
   void Format(Instr* instr, const char* format);
 
   inline int8_t ReadB(uword addr);
   inline uint8_t ReadBU(uword addr);
   inline int16_t ReadH(uword addr, Instr* instr);
   inline uint16_t ReadHU(uword addr, Instr *instr);
   inline intptr_t ReadW(uword addr, Instr* instr);
 
@@ skipping 57 matching lines @@
   }
 
   friend class SimulatorDebugger;
   friend class SimulatorSetjmpBuffer;
   DISALLOW_COPY_AND_ASSIGN(Simulator);
 };
 
 }  // namespace dart
 
 #endif  // VM_SIMULATOR_MIPS_H_