Blink GC plugin: Ensure that classes with virtual trace methods always have vtables for their left-…

tools/clang/blink_gc_plugin/Config.h

 // Copyright 2014 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.
 
 // This file defines the names used by GC infrastructure.
 
 #ifndef TOOLS_BLINK_GC_PLUGIN_CONFIG_H_
 #define TOOLS_BLINK_GC_PLUGIN_CONFIG_H_
 
 #include "clang/AST/AST.h"
@@ skipping 87 matching lines @@
   static bool HasIgnorableDestructor(const std::string& ns,
                                      const std::string& name) {
     return ns == "blink" && name == "ScriptWrappable";
   }
 
   // Assumes name is a valid collection name.
   static size_t CollectionDimension(const std::string& name) {
     return (IsHashMap(name) || name == "pair") ? 2 : 1;
   }
 
+  static bool IsDummyBase(const std::string& name) {
+    return name == "DummyBase";
+  }
+
+  static bool IsRefCountedBase(const std::string& name) {
+    return name == "RefCounted" ||
+           name == "ThreadSafeRefCounted";
+  }
+
   static bool IsGCMixinBase(const std::string& name) {
     return name == "GarbageCollectedMixin";
   }
 
   static bool IsGCFinalizedBase(const std::string& name) {
     return name == "GarbageCollectedFinalized" ||
-           name == "RefCountedGarbageCollected";
+           name == "RefCountedGarbageCollected" ||
+           name == "ThreadSafeRefCountedGarbageCollected";
   }
 
   static bool IsGCBase(const std::string& name) {
     return name == "GarbageCollected" ||
            IsGCFinalizedBase(name) ||
            IsGCMixinBase(name);
   }
 
+  // Returns true of the base classes that do not need a vtable entry for trace
+  // because they cannot possibly initiate a GC during construction.
+  static bool IsSafePolymorphicBase(const std::string& name) {
+    return IsGCBase(name) || IsDummyBase(name) || IsRefCountedBase(name);
+  }
+
   static bool IsAnnotated(clang::Decl* decl, const std::string& anno) {
     clang::AnnotateAttr* attr = decl->getAttr<clang::AnnotateAttr>();
     return attr && (attr->getAnnotation() == anno);
   }
 
   static bool IsStackAnnotated(clang::Decl* decl) {
     return IsAnnotated(decl, "blink_stack_allocated");
   }
 
   static bool IsIgnoreAnnotated(clang::Decl* decl) {
@@ skipping 40 matching lines @@
   }
 
   static bool EndsWith(const std::string& str, const std::string& suffix) {
     if (suffix.size() > str.size())
       return false;
     return str.compare(str.size() - suffix.size(), suffix.size(), suffix) == 0;
   }
 };
 
 #endif  // TOOLS_BLINK_GC_PLUGIN_CONFIG_H_