Add support for debug break in Dart source.

runtime/vm/simulator_arm64.cc

 // 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.
 
 #include <setjmp.h>  // NOLINT
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM64)
 
@@ skipping 1680 matching lines @@
     SimulatorDebugger dbg(this);
     uint16_t imm = static_cast<uint16_t>(instr->Imm16Field());
     char buffer[32];
     snprintf(buffer, sizeof(buffer), "brk #0x%x", imm);
     set_pc(get_pc() + Instr::kInstrSize);
     dbg.Stop(instr, buffer);
   } else if ((instr->Bits(0, 2) == 0) && (instr->Bits(2, 3) == 0) &&
              (instr->Bits(21, 3) == 2)) {
     // Format(instr, "hlt 'imm16");
     uint16_t imm = static_cast<uint16_t>(instr->Imm16Field());
-    if (imm == Instr::kSimulatorMessageCode) {
+    if (imm == Instr::kStopMessageCode) {
       SimulatorDebugger dbg(this);
       const char* message = *reinterpret_cast<const char**>(
           reinterpret_cast<intptr_t>(instr) - 2 * Instr::kInstrSize);
       set_pc(get_pc() + Instr::kInstrSize);
       dbg.Stop(instr, message);
     } else if (imm == Instr::kSimulatorBreakCode) {
       SimulatorDebugger dbg(this);
       dbg.Stop(instr, "breakpoint");
     } else if (imm == Instr::kSimulatorRedirectCode) {
       DoRedirectedCall(instr);
@@ skipping 1782 matching lines @@
   set_register(NULL, kExceptionObjectReg, bit_cast<int64_t>(raw_exception));
   set_register(NULL, kStackTraceObjectReg, bit_cast<int64_t>(raw_stacktrace));
   buf->Longjmp();
 }
 
 }  // namespace dart
 
 #endif  // !defined(HOST_ARCH_ARM64)
 
 #endif  // defined TARGET_ARCH_ARM64