Adds debugger patching to arm64.

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 <math.h>  // for isnan.
 #include <setjmp.h>
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM64)
@@ skipping 2192 matching lines @@
       break;
     case 2:
       // Format(instr, "faddd 'vd, 'vn, 'vm");
       result = vn_val + vm_val;
       break;
     case 3:
       // Format(instr, "fsubd 'vd, 'vn, 'vm");
       result = vn_val - vm_val;
       break;
     default:
-      // Unknown(instr);
-      break;
+      UnimplementedInstruction(instr);
+      return;
   }
 
   set_vregisterd(vd, bit_cast<int64_t, double>(result));
 }
 
 
 void Simulator::DecodeFPCompare(Instr* instr) {
   const VRegister vn = instr->VnField();
   const VRegister vm = instr->VmField();
-  const double vn_val = get_vregisterd(vn);
+  const double vn_val = bit_cast<double, int64_t>(get_vregisterd(vn));
   double vm_val;
 
   if ((instr->Bit(22) == 1) && (instr->Bits(3, 2) == 0)) {
     // Format(instr, "fcmpd 'vn, 'vm");
-    vm_val = get_vregisterd(vm);
+    vm_val = bit_cast<double, int64_t>(get_vregisterd(vm));
   } else if ((instr->Bit(22) == 1) && (instr->Bits(3, 2) == 1)) {
     if (instr->VmField() == V0) {
       // Format(instr, "fcmpd 'vn, #0.0");
       vm_val = 0.0;
     } else {
       UnimplementedInstruction(instr);
       return;
     }
   } else {
     UnimplementedInstruction(instr);
@@ skipping 232 matching lines @@
   set_register(kExceptionObjectReg, bit_cast<int64_t>(raw_exception));
   set_register(kStackTraceObjectReg, bit_cast<int64_t>(raw_stacktrace));
   buf->Longjmp();
 }
 
 }  // namespace dart
 
 #endif  // !defined(HOST_ARCH_ARM64)
 
 #endif  // defined TARGET_ARCH_ARM64