Enable the profiler on the simulator

runtime/vm/assembler_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_ASSEMBLER_ARM64_H_
 #define VM_ASSEMBLER_ARM64_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_arm64.h directly; use assembler.h instead.
 #endif
@@ skipping 1699 matching lines @@
   }
 
   void EmitLoadStoreRegPair(LoadStoreRegPairOp op,
                             Register rt, Register rt2, Address a,
                             OperandSize sz) {
     ASSERT((sz == kDoubleWord) || (sz == kWord) || (sz == kUnsignedWord));
     ASSERT((rt != CSP) && (rt != R31));
     ASSERT((rt2 != CSP) && (rt2 != R31));
     const Register crt = ConcreteRegister(rt);
     const Register crt2 = ConcreteRegister(rt2);
-    int32_t opc;
+    int32_t opc = 0;

[Cutch, 2014/11/14 17:15:30]

Fixes Mac compilation error.

     switch (sz) {
       case kDoubleWord: opc = B31; break;
       case kWord: opc = B30; break;
       case kUnsignedWord: opc = 0; break;
       default: UNREACHABLE(); break;
     }
     const int32_t encoding =
       opc | op |
       (static_cast<int32_t>(crt) << kRtShift) |
       (static_cast<int32_t>(crt2) << kRt2Shift) |
@@ skipping 152 matching lines @@
                                   Register value,
                                   Label* no_update);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_ARM64_H_