Complete and clean up breakpoint support in all 3 debuggers embedded in MIPS,

runtime/vm/constants_arm64.h

 // Copyright (c) 2014, 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.
 
 #ifndef VM_CONSTANTS_ARM64_H_
 #define VM_CONSTANTS_ARM64_H_
 
 #include "platform/assert.h"
 
 namespace dart {
@@ skipping 735 matching lines @@
   kExtendTypeBits = 3,
 
   // Hint Fields.
   kHintCRmShift = 8,
   kHintCRmBits = 4,
   kHintOp2Shift = 5,
   kHintOp2Bits = 3,
 };
 
 
-const uint32_t kImmExceptionIsRedirectedCall = 0xca11;
-const uint32_t kImmExceptionIsUnreachable = 0xdebf;
-const uint32_t kImmExceptionIsDebug = 0xdeb0;
-const uint32_t kImmExceptionIsPrintf = 0xdeb1;
-
 // Helper functions for decoding logical immediates.
 static inline uint64_t RotateRight(
     uint64_t value, uint8_t rotate, uint8_t width) {
   ASSERT(width <= 64);
   rotate &= 63;
   return ((value & ((1UL << rotate) - 1UL)) << (width - rotate)) |
          (value >> rotate);
 }
 
 static inline uint64_t RepeatBitsAcrossReg(
@@ skipping 21 matching lines @@
 //
 class Instr {
  public:
   enum {
     kInstrSize = 4,
     kInstrSizeLog2 = 2,
     kPCReadOffset = 8
   };
 
   static const int32_t kNopInstruction = HINT;  // hint #0 === nop.
-  static const int32_t kBreakPointInstruction =  // hlt #kImmExceptionIsDebug.
-      HLT | (kImmExceptionIsDebug << kImm16Shift);
-  static const int kBreakPointInstructionSize = kInstrSize;
+
+  // Reserved brk and hlt instruction codes.
+  static const int32_t kBreakPointCode = 0xdeb0;  // For breakpoint.
+  static const int32_t kStopMessageCode = 0xdeb1;  // For Stop(message).
+  static const int32_t kSimulatorMessageCode = 0xdeb2;  // For trace msg in sim.
+  static const int32_t kSimulatorBreakCode = 0xdeb3;  // For breakpoint in sim.
+  static const int32_t kSimulatorRedirectCode = 0xca11;  // For redirection.
+
+  // Breakpoint instruction filling assembler code buffers in debug mode.
+  static const int32_t kBreakPointInstruction =  // brk(0xdeb0).
+      BRK | (kBreakPointCode << kImm16Shift);
+
+  // Breakpoint instruction used by the simulator.
+  // Should be distinct from kBreakPointInstruction and from a typical user
+  // breakpoint inserted in generated code for debugging, e.g. brk(0).
+  static const int32_t kSimulatorBreakpointInstruction =
+      HLT | (kSimulatorBreakCode << kImm16Shift);
+
+  // Runtime call redirection instruction used by the simulator.
   static const int32_t kRedirectInstruction =
-      HLT | (kImmExceptionIsRedirectedCall << kImm16Shift);
+      HLT | (kSimulatorRedirectCode << kImm16Shift);
 
   // Read one particular bit out of the instruction bits.
   inline int Bit(int nr) const {
     return (InstructionBits() >> nr) & 1;
   }
 
   // Read a bit field out of the instruction bits.
   inline int Bits(int shift, int count) const {
     return (InstructionBits() >> shift) & ((1 << count) - 1);
   }
@@ skipping 230 matching lines @@
   static Instr* At(uword pc) { return reinterpret_cast<Instr*>(pc); }
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
 };
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_ARM64_H_