Initial UserTag and dart:profiler library

runtime/vm/tags.cc

 // Copyright (c) 2014, 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 "vm/tags.h"
 
 #include "vm/isolate.h"
 #include "vm/json_stream.h"
 #include "vm/native_entry.h"
 #include "vm/runtime_entry.h"
+#include "vm/object.h"
 
 namespace dart {
 
 const char* VMTag::TagName(uword tag) {
   if (IsNativeEntryTag(tag)) {
     const uint8_t* native_reverse_lookup = NativeEntry::ResolveSymbol(tag);
     if (native_reverse_lookup != NULL) {
       return reinterpret_cast<const char*>(native_reverse_lookup);
     }
     return "Unknown native entry";
@@ skipping 110 matching lines @@
     }
   }
   {
     JSONArray arr(obj, "counters");
     for (intptr_t i = 1; i < VMTag::kNumVMTags; i++) {
       arr.AddValue64(counters_[i]);
     }
   }
 }
 
+
+const char* UserTags::TagName(uword tag_address) {
+  ASSERT(tag_address >= kUserTagIdOffset);
+  ASSERT(tag_address < kUserTagIdOffset + kMaxUserTags);
+  Isolate* isolate = Isolate::Current();
+  const UserTag& tag =
+      UserTag::Handle(isolate, UserTag::FindTagById(tag_address));
+  ASSERT(!tag.IsNull());
+  const String& label = String::Handle(isolate, tag.label());
+  return label.ToCString();
+}
+
+
 }  // namespace dart