Global cycle detection analysis.

tools/clang/blink_gc_plugin/Edge.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.
 
 #ifndef TOOLS_BLINK_GC_PLUGIN_EDGE_H_
 #define TOOLS_BLINK_GC_PLUGIN_EDGE_H_
 
 #include <deque>
 
 #include "TracingStatus.h"
@@ skipping 54 matching lines @@
   virtual void AtCollection(Collection*);
 
  private:
   Context context_;
 };
 
 // Base class for all edges.
 class Edge {
  public:
   enum NeedsTracingOption { kRecursive, kNonRecursive };
+  enum LivenessKind { kWeak, kStrong, kRoot };
 
   virtual ~Edge() { }
+  virtual LivenessKind Kind() = 0;
   virtual void Accept(EdgeVisitor*) = 0;
   virtual bool NeedsFinalization() = 0;
   virtual TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Unknown();
   }
 
   virtual bool IsValue() { return false; }
   virtual bool IsRawPtr() { return false; }
   virtual bool IsRefPtr() { return false; }
   virtual bool IsOwnPtr() { return false; }
   virtual bool IsMember() { return false; }
   virtual bool IsWeakMember() { return false; }
   virtual bool IsPersistent() { return false; }
   virtual bool IsCollection() { return false; }
 };
 
 // A value edge is a direct edge to some type, eg, part-object edges.
 class Value : public Edge {
  public:
   explicit Value(RecordInfo* value) : value_(value) {};
   bool IsValue() { return true; }
+  LivenessKind Kind() { return kStrong; }
   bool NeedsFinalization();
   TracingStatus NeedsTracing(NeedsTracingOption);
   void Accept(EdgeVisitor* visitor) { visitor->VisitValue(this); }
   RecordInfo* value() { return value_; }
  private:
   RecordInfo* value_;
 };
 
 // Shared base for smart-pointer edges.
 class PtrEdge : public Edge {
  public:
   ~PtrEdge() { delete ptr_; }
   Edge* ptr() { return ptr_; }
  protected:
   PtrEdge(Edge* ptr) : ptr_(ptr) {
     assert(ptr && "EdgePtr pointer must be non-null");
   }
  private:
   Edge* ptr_;
 };
 
 class RawPtr : public PtrEdge {
  public:
   explicit RawPtr(Edge* ptr) : PtrEdge(ptr) { }
   bool IsRawPtr() { return true; }
+  LivenessKind Kind() { return kWeak; }
   bool NeedsFinalization() { return false; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Unneeded();
   }
   void Accept(EdgeVisitor* visitor) { visitor->VisitRawPtr(this); }
 };
 
 class RefPtr : public PtrEdge {
  public:
   explicit RefPtr(Edge* ptr) : PtrEdge(ptr) { }
   bool IsRefPtr() { return true; }
+  LivenessKind Kind() { return kStrong; }
   bool NeedsFinalization() { return true; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Unneeded();
   }
   void Accept(EdgeVisitor* visitor) { visitor->VisitRefPtr(this); }
 };
 
 class OwnPtr : public PtrEdge {
  public:
   explicit OwnPtr(Edge* ptr) : PtrEdge(ptr) { }
   bool IsOwnPtr() { return true; }
+  LivenessKind Kind() { return kStrong; }
   bool NeedsFinalization() { return true; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Unneeded();
   }
   void Accept(EdgeVisitor* visitor) { visitor->VisitOwnPtr(this); }
 };
 
 class Member : public PtrEdge {
  public:
   explicit Member(Edge* ptr) : PtrEdge(ptr) { }
   bool IsMember() { return true; }
+  LivenessKind Kind() { return kStrong; }
   bool NeedsFinalization() { return false; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Needed();
   }
   void Accept(EdgeVisitor* visitor) { visitor->VisitMember(this); }
 };
 
 class WeakMember : public PtrEdge {
  public:
   explicit WeakMember(Edge* ptr) : PtrEdge(ptr) { }
   bool IsWeakMember() { return true; }
+  LivenessKind Kind() { return kWeak; }
   bool NeedsFinalization() { return false; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Needed();
   }
   void Accept(EdgeVisitor* visitor) { visitor->VisitWeakMember(this); }
 };
 
 class Persistent : public PtrEdge {
  public:
   explicit Persistent(Edge* ptr) : PtrEdge(ptr) { }
   bool IsPersistent() { return true; }
+  LivenessKind Kind() { return kRoot; }
   bool NeedsFinalization() { return true; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Unneeded();
   }
   void Accept(EdgeVisitor* visitor) { visitor->VisitPersistent(this); }
 };
 
 class Collection : public Edge {
  public:
   typedef std::vector<Edge*> Members;
   Collection(RecordInfo* info, bool on_heap, bool is_root)
       : info_(info),
         on_heap_(on_heap),
         is_root_(is_root) {}
   ~Collection() {
     for (Members::iterator it = members_.begin(); it != members_.end(); ++it) {
       assert(*it && "Collection-edge members must be non-null");
       delete *it;
     }
   }
   bool IsCollection() { return true; }
+  LivenessKind Kind() { return is_root_ ? kRoot : kStrong; }
   bool on_heap() { return on_heap_; }
   bool is_root() { return is_root_; }
   Members& members() { return members_; }
   void Accept(EdgeVisitor* visitor) { visitor->VisitCollection(this); }
   void AcceptMembers(EdgeVisitor* visitor) {
     for (Members::iterator it = members_.begin(); it != members_.end(); ++it)
       (*it)->Accept(visitor);
   }
   bool NeedsFinalization();
   TracingStatus NeedsTracing(NeedsTracingOption) {
@@ skipping 10 matching lines @@
     return status;
   }
  private:
   RecordInfo* info_;
   Members members_;
   bool on_heap_;
   bool is_root_;
 };
 
 #endif // TOOLS_BLINK_GC_PLUGIN_EDGE_H_