Basic tag infrastructure

runtime/vm/tags.h

Index: runtime/vm/tags.h
diff --git a/runtime/vm/tags.h b/runtime/vm/tags.h
new file mode 100644
index 0000000000000000000000000000000000000000..98be468cbf79bc429aedceb4b9960f9bcf593758
--- /dev/null
+++ b/runtime/vm/tags.h
@@ -0,0 +1,58 @@
+// 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.
+
+#ifndef VM_TAGS_H_
+#define VM_TAGS_H_
+
+#include "vm/allocation.h"
+
+class Isolate;
+
+namespace dart {
+
+#define VM_TAG_LIST(V)                                                         \
+  V(VM) /* Catch all */                                                        \
+  V(Compile)                                                                   \
+  V(Script)                                                                    \
+  V(GCNewSpace)                                                                \
+  V(GCOldSpace)                                                                \
+  V(RuntimeNative)                                                             \
+  V(Idle)                                                                      \
+
+
+class VMTag : public AllStatic {
+ public:
+  enum VMTagId {
+    kInvalidTagId = 0,
+#define DEFINE_VM_TAG_ID(tag)                                                  \
+    k##tag##TagId,
+    VM_TAG_LIST(DEFINE_VM_TAG_ID)
+#undef DEFINE_VM_TAG_KIND
+    kNumVMTags,
+  };
+
+  static const char* TagName(uword id);
+
+ private:
+  struct TagEntry {
+    const char* name;
+    uword id;
+  };
+  static TagEntry entries_[];
+};
+
+class VMTagScope : StackResource {
+ public:
+  VMTagScope(Isolate* isolate, uword tag);
+  ~VMTagScope();
+ private:
+  uword previous_tag_;
+
+  DISALLOW_ALLOCATION();
+  DISALLOW_IMPLICIT_CONSTRUCTORS(VMTagScope);
+};
+
+}  // namespace dart
+
+#endif  // VM_TAGS_H_