Fix PcDescriptor iteratot to never return a pointer to a memory location since the data can move wi…

runtime/vm/simulator_arm.cc

 // 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.
 
 #include <setjmp.h>
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM)
 
@@ skipping 253 matching lines @@
 }
 
 
 intptr_t SimulatorDebugger::GetApproximateTokenIndex(const Code& code,
                                                      uword pc) {
   intptr_t token_pos = -1;
   const PcDescriptors& descriptors =
       PcDescriptors::Handle(code.pc_descriptors());
   PcDescriptors::Iterator iter(descriptors, RawPcDescriptors::kAnyKind);
   while (iter.HasNext()) {
-    const RawPcDescriptors::PcDescriptorRec& rec = iter.Next();
+    RawPcDescriptors::PcDescriptorRec rec;
+    iter.NextRec(&rec);
     if (rec.pc() == pc) {
       return rec.token_pos();
     } else if ((token_pos <= 0) && (rec.pc() > pc)) {
       token_pos = rec.token_pos();
     }
   }
   return token_pos;
 }
 
 
@@ skipping 3438 matching lines @@
   set_register(kExceptionObjectReg, bit_cast<int32_t>(raw_exception));
   set_register(kStackTraceObjectReg, bit_cast<int32_t>(raw_stacktrace));
   buf->Longjmp();
 }
 
 }  // namespace dart
 
 #endif  // !defined(HOST_ARCH_ARM)
 
 #endif  // defined TARGET_ARCH_ARM