Make VM state tracking to be independent of logging and profiling.

src/vm-state.h

Index: src/vm-state.h
diff --git a/src/vm-state.h b/src/vm-state.h
new file mode 100644
index 0000000000000000000000000000000000000000..a188c5d2f830a7143fc51447a989735b5f3989fa
--- /dev/null
+++ b/src/vm-state.h
@@ -0,0 +1,70 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_VM_STATE_H_
+#define V8_VM_STATE_H_
+
+namespace v8 {
+namespace internal {
+
+class VMState BASE_EMBEDDED {
+#ifdef ENABLE_VMSTATE_TRACKING
+ public:
+  inline VMState(StateTag state);
+  inline ~VMState();
+
+  StateTag state() { return state_; }
+  void set_external_callback(Address external_callback) {
+    external_callback_ = external_callback;
+  }
+
+  static StateTag current_state() {
+    return current_state_ ? current_state_->state() : EXTERNAL;
+  }
+
+  static Address external_callback() {
+    return current_state_ ? current_state_->external_callback_ : NULL;
+  }
+
+ private:
+  bool disabled_;
+  StateTag state_;
+  VMState* previous_;
+  Address external_callback_;
+
+  // A stack of VM states.
+  static VMState* current_state_;
+#else
+ public:
+  explicit VMState(StateTag state) {}
+#endif
+};
+
+} }  // namespace v8::internal
+
+
+#endif  // V8_VM_STATE_H_