blink_gc_plugin: detect singletons with embedded ScriptWrappables.

tools/clang/blink_gc_plugin/Config.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "Config.h"
 
 #include <cassert>
 
 #include "clang/AST/AST.h"
 
@@ skipping 31 matching lines @@
 void Config::UseLegacyNames() {
   kCreateName = legacy::kCreateName;
   kTraceName = legacy::kTraceName;
   kFinalizeName = legacy::kFinalizeName;
   kTraceAfterDispatchName = legacy::kTraceAfterDispatchName;
   kRegisterWeakMembersName = legacy::kRegisterWeakMembersName;
   kAdjustAndMarkName = legacy::kAdjustAndMarkName;
   kIsHeapObjectAliveName = legacy::kIsHeapObjectAliveName;
 }
 
+bool Config::IsAnnotated(clang::Decl* decl, const std::string& anno) {
+  if (!decl->hasAttrs())
+    return false;
+
+  for (const clang::Attr* attr : decl->getAttrs()) {
+    const clang::AnnotateAttr* annotation = dyn_cast<clang::AnnotateAttr>(attr);
+    if (annotation && annotation->getAnnotation() == anno)
+      return true;
+  }
+  return false;
+}
+
 bool Config::IsTemplateInstantiation(CXXRecordDecl* record) {
   ClassTemplateSpecializationDecl* spec =
       dyn_cast<clang::ClassTemplateSpecializationDecl>(record);
   if (!spec)
     return false;
   switch (spec->getTemplateSpecializationKind()) {
     case TSK_ImplicitInstantiation:
     case TSK_ExplicitInstantiationDefinition:
       return true;
     case TSK_Undeclared:
     case TSK_ExplicitSpecialization:
       return false;
     // TODO: unsupported cases.
     case TSK_ExplicitInstantiationDeclaration:
       return false;
   }
   assert(false && "Unknown template specialization kind");
   return false;
 }