--- a/xpcom/base/nsCycleCollector.cpp
+++ b/xpcom/base/nsCycleCollector.cpp
@@ -1563,17 +1563,17 @@ public:
 
     bool WantAllTraces() const
     {
         return nsCycleCollectionNoteRootCallback::WantAllTraces();
     }
 
     uint32_t Count() const { return mPtrToNodeMap.entryCount; }
 
-    PtrInfo* AddNode(void *s, nsCycleCollectionParticipant *aParticipant);
+    PtrInfo* AddNode(void *aPtr, nsCycleCollectionParticipant *aParticipant);
     PtrInfo* AddWeakMapNode(void* node);
     void Traverse(PtrInfo* aPtrInfo);
     void SetLastChild();
 
     bool RanOutOfMemory() const { return mRanOutOfMemory; }
 
 private:
     void DescribeNode(uint32_t refCount, const char *objName)
@@ -1682,28 +1682,28 @@ GCGraphBuilder::GCGraphBuilder(nsCycleCo
 
 GCGraphBuilder::~GCGraphBuilder()
 {
     if (mPtrToNodeMap.ops)
         PL_DHashTableFinish(&mPtrToNodeMap);
 }
 
 PtrInfo*
-GCGraphBuilder::AddNode(void *s, nsCycleCollectionParticipant *aParticipant)
+GCGraphBuilder::AddNode(void *aPtr, nsCycleCollectionParticipant *aParticipant)
 {
-    PtrToNodeEntry *e = static_cast<PtrToNodeEntry*>(PL_DHashTableOperate(&mPtrToNodeMap, s, PL_DHASH_ADD));
+    PtrToNodeEntry *e = static_cast<PtrToNodeEntry*>(PL_DHashTableOperate(&mPtrToNodeMap, aPtr, PL_DHASH_ADD));
     if (!e) {
         mRanOutOfMemory = true;
         return nullptr;
     }
 
     PtrInfo *result;
     if (!e->mNode) {
         // New entry.
-        result = mNodeBuilder.Add(s, aParticipant);
+        result = mNodeBuilder.Add(aPtr, aParticipant);
         e->mNode = result;
         NS_ASSERTION(result, "mNodeBuilder.Add returned null");
     } else {
         result = e->mNode;
         MOZ_ASSERT(result->mParticipant == aParticipant,
                    "nsCycleCollectionParticipant shouldn't change!");
     }
     return result;