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

runtime/vm/profiler.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 "platform/utils.h"
 
 #include "vm/allocation.h"
 #include "vm/atomic.h"
 #include "vm/code_patcher.h"
 #include "vm/isolate.h"
@@ skipping 1851 matching lines @@
   ASSERT(counters != NULL);
   counters->Increment(isolate->vm_tag());
   IsolateProfilerData* profiler_data = isolate->profiler_data();
   if (profiler_data == NULL) {
     return;
   }
   SampleBuffer* sample_buffer = profiler_data->sample_buffer();
   if (sample_buffer == NULL) {
     return;
   }
+  if (StubCode::InJumpToExceptionHandlerStub(state.pc)) {
+    // The JumpToExceptionHandler stub manually adjusts the stack pointer,
+    // frame pointer, and some isolate state before jumping to a catch entry.
+    // It is not safe to walk the stack when executing this stub.
+    return;
+  }

[siva, 2014/07/16 17:54:09]

Maybe move this bail out further up.

   Sample* sample = sample_buffer->ReserveSample();
   sample->Init(isolate, OS::GetCurrentTimeMicros(), state.tid);
   sample->set_vm_tag(isolate->vm_tag());
   sample->set_user_tag(isolate->user_tag());
   sample->set_sp(state.sp);
   sample->set_fp(state.fp);
 
   uword stack_lower = 0;
   uword stack_upper = 0;
   isolate->GetStackBounds(&stack_lower, &stack_upper);
   if ((stack_lower == 0) || (stack_upper == 0)) {
     stack_lower = 0;
     stack_upper = 0;
   }
   if (FLAG_profile_vm) {
     // Collect native and Dart frames.
     ProfilerNativeStackWalker stackWalker(sample, stack_lower, stack_upper,
                                           state.pc, state.fp, state.sp);
     stackWalker.walk(isolate->heap());
   } else {
     if ((isolate->stub_code() != NULL) &&
-        (isolate->top_exit_frame_info() != 0)) {
-      // Collect only Dart frames.
+        (isolate->top_exit_frame_info() != 0) &&
+        (isolate->vm_tag() != VMTag::kScriptTagId)) {
+      // We have a valid exit frame info, use the Dart stack walker.
       ProfilerDartStackWalker stackWalker(isolate, sample);
       stackWalker.walk();
     } else {
       // Collect native and Dart frames.
       ProfilerNativeStackWalker stackWalker(sample, stack_lower, stack_upper,
                                             state.pc, state.fp, state.sp);
       stackWalker.walk(isolate->heap());
     }
   }
 }
 
 }  // namespace dart