Move some isolate state setup from C++ code to JumpToExceptionHandler stub

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 3673 matching lines @@
     return_value = Utils::LowHighTo64Bits(get_register(R0), get_register(R1));
   }
   return return_value;
 }
 
 
 void Simulator::Longjmp(uword pc,
                         uword sp,
                         uword fp,
                         RawObject* raw_exception,
-                        RawObject* raw_stacktrace) {
+                        RawObject* raw_stacktrace,
+                        Isolate* isolate) {
   // Walk over all setjmp buffers (simulated --> C++ transitions)
   // and try to find the setjmp associated with the simulated stack pointer.
   SimulatorSetjmpBuffer* buf = last_setjmp_buffer();
   while (buf->link() != NULL && buf->link()->sp() <= sp) {
     buf = buf->link();
   }
   ASSERT(buf != NULL);
 
   // The C++ caller has not cleaned up the stack memory of C++ frames.
   // Prepare for unwinding frames by destroying all the stack resources
   // in the previous C++ frames.
   uword native_sp = buf->native_sp();
-  Isolate* isolate = Isolate::Current();
   while (isolate->top_resource() != NULL &&
          (reinterpret_cast<uword>(isolate->top_resource()) < native_sp)) {
     isolate->top_resource()->~StackResource();
   }
 
   // Unwind the C++ stack and continue simulation in the target frame.
   set_register(PC, static_cast<int32_t>(pc));
   set_register(SP, static_cast<int32_t>(sp));
   set_register(FP, static_cast<int32_t>(fp));
+  // Set the tag.
+  isolate->set_vm_tag(VMTag::kScriptTagId);
+  // Clear top exit frame.
+  isolate->set_top_exit_frame_info(0);
 
   ASSERT(raw_exception != Object::null());
   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