diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 327ce75..41cca68 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -2793,7 +2793,7 @@
                               Attributes::get(RetType->getContext(),
                                               FuncAttrs)));
 
-  AttrListPtr PAL = AttrListPtr::get(Attrs);
+  AttrListPtr PAL = AttrListPtr::get(Context, Attrs);
 
   if (PAL.getParamAttributes(1).hasAttribute(Attributes::StructRet) &&
       !RetType->isVoidTy())
@@ -3350,7 +3350,7 @@
                                               FnAttrs)));
 
   // Finish off the Attributes and check them
-  AttrListPtr PAL = AttrListPtr::get(Attrs);
+  AttrListPtr PAL = AttrListPtr::get(Context, Attrs);
 
   InvokeInst *II = InvokeInst::Create(Callee, NormalBB, UnwindBB, Args);
   II->setCallingConv(CC);
@@ -3752,7 +3752,7 @@
                                               FnAttrs)));
 
   // Finish off the Attributes and check them
-  AttrListPtr PAL = AttrListPtr::get(Attrs);
+  AttrListPtr PAL = AttrListPtr::get(Context, Attrs);
 
   CallInst *CI = CallInst::Create(Callee, Args);
   CI->setTailCall(isTail);
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index ac29830..b973ea4 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -487,7 +487,7 @@
                                                   Attributes::get(Context, B)));
       }
 
-      MAttributes.push_back(AttrListPtr::get(Attrs));
+      MAttributes.push_back(AttrListPtr::get(Context, Attrs));
       Attrs.clear();
       break;
     }
diff --git a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
index 8a0274b..be48b20 100644
--- a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -611,7 +611,7 @@
   
   // Recompute the parameter attributes list based on the new arguments for
   // the function.
-  NF->setAttributes(AttrListPtr::get(AttributesVec));
+  NF->setAttributes(AttrListPtr::get(F->getContext(), AttributesVec));
   AttributesVec.clear();
 
   F->getParent()->getFunctionList().insert(F, NF);
@@ -731,11 +731,13 @@
       New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(),
                                Args, "", Call);
       cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv());
-      cast<InvokeInst>(New)->setAttributes(AttrListPtr::get(AttributesVec));
+      cast<InvokeInst>(New)->setAttributes(AttrListPtr::get(II->getContext(),
+                                                            AttributesVec));
     } else {
       New = CallInst::Create(NF, Args, "", Call);
       cast<CallInst>(New)->setCallingConv(CS.getCallingConv());
-      cast<CallInst>(New)->setAttributes(AttrListPtr::get(AttributesVec));
+      cast<CallInst>(New)->setAttributes(AttrListPtr::get(New->getContext(),
+                                                          AttributesVec));
       if (cast<CallInst>(Call)->isTailCall())
         cast<CallInst>(New)->setTailCall();
     }
diff --git a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
index fc22548..4cfd0b2 100644
--- a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -280,7 +280,7 @@
       if (FnAttrs.hasAttributes())
         AttributesVec.push_back(AttributeWithIndex::get(AttrListPtr::FunctionIndex,
                                                         FnAttrs));
-      PAL = AttrListPtr::get(AttributesVec);
+      PAL = AttrListPtr::get(Fn.getContext(), AttributesVec);
     }
 
     Instruction *New;
@@ -806,7 +806,7 @@
                                                     FnAttrs));
 
   // Reconstruct the AttributesList based on the vector we constructed.
-  AttrListPtr NewPAL = AttrListPtr::get(AttributesVec);
+  AttrListPtr NewPAL = AttrListPtr::get(F->getContext(), AttributesVec);
 
   // Create the new function type based on the recomputed parameters.
   FunctionType *NFTy = FunctionType::get(NRetTy, Params, FTy->isVarArg());
@@ -874,7 +874,7 @@
                                                       FnAttrs));
 
     // Reconstruct the AttributesList based on the vector we constructed.
-    AttrListPtr NewCallPAL = AttrListPtr::get(AttributesVec);
+    AttrListPtr NewCallPAL = AttrListPtr::get(F->getContext(), AttributesVec);
 
     Instruction *New;
     if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 5ad6f91..48f2704 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1177,7 +1177,8 @@
   if (NewRetTy->isVoidTy())
     Caller->setName("");   // Void type should not have a name.
 
-  const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec);
+  const AttrListPtr &NewCallerPAL = AttrListPtr::get(Callee->getContext(),
+                                                     attrVec);
 
   Instruction *NC;
   if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
@@ -1355,7 +1356,7 @@
         NestF->getType() == PointerType::getUnqual(NewFTy) ?
         NestF : ConstantExpr::getBitCast(NestF,
                                          PointerType::getUnqual(NewFTy));
-      const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs);
+      const AttrListPtr &NewPAL = AttrListPtr::get(FTy->getContext(), NewAttrs);
 
       Instruction *NewCaller;
       if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index fa2faa2..74b2ee1 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -47,7 +47,9 @@
                                    ArrayRef<Attributes::AttrVal>(AVs, 2));
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Constant *StrLen = M->getOrInsertFunction("strlen", AttrListPtr::get(AWI),
+  Constant *StrLen = M->getOrInsertFunction("strlen",
+                                            AttrListPtr::get(M->getContext(),
+                                                             AWI),
                                             TD->getIntPtrType(Context),
                                             B.getInt8PtrTy(),
                                             NULL);
@@ -74,7 +76,9 @@
                                    ArrayRef<Attributes::AttrVal>(AVs, 2));
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Constant *StrNLen = M->getOrInsertFunction("strnlen", AttrListPtr::get(AWI),
+  Constant *StrNLen = M->getOrInsertFunction("strnlen",
+                                             AttrListPtr::get(M->getContext(),
+                                                              AWI),
                                              TD->getIntPtrType(Context),
                                              B.getInt8PtrTy(),
                                              TD->getIntPtrType(Context),
@@ -102,7 +106,9 @@
 
   Type *I8Ptr = B.getInt8PtrTy();
   Type *I32Ty = B.getInt32Ty();
-  Constant *StrChr = M->getOrInsertFunction("strchr", AttrListPtr::get(AWI),
+  Constant *StrChr = M->getOrInsertFunction("strchr",
+                                            AttrListPtr::get(M->getContext(),
+                                                             AWI),
                                             I8Ptr, I8Ptr, I32Ty, NULL);
   CallInst *CI = B.CreateCall2(StrChr, CastToCStr(Ptr, B),
                                ConstantInt::get(I32Ty, C), "strchr");
@@ -127,7 +133,9 @@
                                    ArrayRef<Attributes::AttrVal>(AVs, 2));
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Value *StrNCmp = M->getOrInsertFunction("strncmp", AttrListPtr::get(AWI),
+  Value *StrNCmp = M->getOrInsertFunction("strncmp",
+                                          AttrListPtr::get(M->getContext(),
+                                                           AWI),
                                           B.getInt32Ty(),
                                           B.getInt8PtrTy(),
                                           B.getInt8PtrTy(),
@@ -155,7 +163,8 @@
   AWI[1] = AttributeWithIndex::get(M->getContext(), AttrListPtr::FunctionIndex,
                                    Attributes::NoUnwind);
   Type *I8Ptr = B.getInt8PtrTy();
-  Value *StrCpy = M->getOrInsertFunction(Name, AttrListPtr::get(AWI),
+  Value *StrCpy = M->getOrInsertFunction(Name,
+                                         AttrListPtr::get(M->getContext(), AWI),
                                          I8Ptr, I8Ptr, I8Ptr, NULL);
   CallInst *CI = B.CreateCall2(StrCpy, CastToCStr(Dst, B), CastToCStr(Src, B),
                                Name);
@@ -178,7 +187,9 @@
   AWI[1] = AttributeWithIndex::get(M->getContext(), AttrListPtr::FunctionIndex,
                                    Attributes::NoUnwind);
   Type *I8Ptr = B.getInt8PtrTy();
-  Value *StrNCpy = M->getOrInsertFunction(Name, AttrListPtr::get(AWI),
+  Value *StrNCpy = M->getOrInsertFunction(Name,
+                                          AttrListPtr::get(M->getContext(),
+                                                           AWI),
                                           I8Ptr, I8Ptr, I8Ptr,
                                           Len->getType(), NULL);
   CallInst *CI = B.CreateCall3(StrNCpy, CastToCStr(Dst, B), CastToCStr(Src, B),
@@ -203,7 +214,7 @@
                                 Attributes::NoUnwind);
   LLVMContext &Context = B.GetInsertBlock()->getContext();
   Value *MemCpy = M->getOrInsertFunction("__memcpy_chk",
-                                         AttrListPtr::get(AWI),
+                                         AttrListPtr::get(M->getContext(), AWI),
                                          B.getInt8PtrTy(),
                                          B.getInt8PtrTy(),
                                          B.getInt8PtrTy(),
@@ -231,7 +242,8 @@
   AWI = AttributeWithIndex::get(M->getContext(), AttrListPtr::FunctionIndex,
                                 ArrayRef<Attributes::AttrVal>(AVs, 2));
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Value *MemChr = M->getOrInsertFunction("memchr", AttrListPtr::get(AWI),
+  Value *MemChr = M->getOrInsertFunction("memchr",
+                                         AttrListPtr::get(M->getContext(), AWI),
                                          B.getInt8PtrTy(),
                                          B.getInt8PtrTy(),
                                          B.getInt32Ty(),
@@ -261,7 +273,8 @@
                                    ArrayRef<Attributes::AttrVal>(AVs, 2));
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Value *MemCmp = M->getOrInsertFunction("memcmp", AttrListPtr::get(AWI),
+  Value *MemCmp = M->getOrInsertFunction("memcmp",
+                                         AttrListPtr::get(M->getContext(), AWI),
                                          B.getInt32Ty(),
                                          B.getInt8PtrTy(),
                                          B.getInt8PtrTy(),
@@ -338,7 +351,8 @@
   AWI[1] = AttributeWithIndex::get(M->getContext(), AttrListPtr::FunctionIndex,
                                    Attributes::NoUnwind);
 
-  Value *PutS = M->getOrInsertFunction("puts", AttrListPtr::get(AWI),
+  Value *PutS = M->getOrInsertFunction("puts",
+                                       AttrListPtr::get(M->getContext(), AWI),
                                        B.getInt32Ty(),
                                        B.getInt8PtrTy(),
                                        NULL);
@@ -362,7 +376,8 @@
                                    Attributes::NoUnwind);
   Constant *F;
   if (File->getType()->isPointerTy())
-    F = M->getOrInsertFunction("fputc", AttrListPtr::get(AWI),
+    F = M->getOrInsertFunction("fputc",
+                               AttrListPtr::get(M->getContext(), AWI),
                                B.getInt32Ty(),
                                B.getInt32Ty(), File->getType(),
                                NULL);
@@ -396,7 +411,8 @@
   StringRef FPutsName = TLI->getName(LibFunc::fputs);
   Constant *F;
   if (File->getType()->isPointerTy())
-    F = M->getOrInsertFunction(FPutsName, AttrListPtr::get(AWI),
+    F = M->getOrInsertFunction(FPutsName,
+                               AttrListPtr::get(M->getContext(), AWI),
                                B.getInt32Ty(),
                                B.getInt8PtrTy(),
                                File->getType(), NULL);
@@ -429,7 +445,8 @@
   StringRef FWriteName = TLI->getName(LibFunc::fwrite);
   Constant *F;
   if (File->getType()->isPointerTy())
-    F = M->getOrInsertFunction(FWriteName, AttrListPtr::get(AWI),
+    F = M->getOrInsertFunction(FWriteName,
+                               AttrListPtr::get(M->getContext(), AWI),
                                TD->getIntPtrType(Context),
                                B.getInt8PtrTy(),
                                TD->getIntPtrType(Context),
diff --git a/llvm/lib/VMCore/Attributes.cpp b/llvm/lib/VMCore/Attributes.cpp
index 68aa954..55722bc 100644
--- a/llvm/lib/VMCore/Attributes.cpp
+++ b/llvm/lib/VMCore/Attributes.cpp
@@ -355,62 +355,8 @@
 // AttributeListImpl Definition
 //===----------------------------------------------------------------------===//
 
-namespace llvm {
-  class AttributeListImpl;
-}
-
-static ManagedStatic<FoldingSet<AttributeListImpl> > AttributesLists;
-
-namespace llvm {
-static ManagedStatic<sys::SmartMutex<true> > ALMutex;
-
-class AttributeListImpl : public FoldingSetNode {
-  sys::cas_flag RefCount;
-
-  // AttributesList is uniqued, these should not be publicly available.
-  void operator=(const AttributeListImpl &) LLVM_DELETED_FUNCTION;
-  AttributeListImpl(const AttributeListImpl &) LLVM_DELETED_FUNCTION;
-  ~AttributeListImpl();                        // Private implementation
-public:
-  SmallVector<AttributeWithIndex, 4> Attrs;
-
-  AttributeListImpl(ArrayRef<AttributeWithIndex> attrs)
-    : Attrs(attrs.begin(), attrs.end()) {
-    RefCount = 0;
-  }
-
-  void AddRef() {
-    sys::SmartScopedLock<true> Lock(*ALMutex);
-    ++RefCount;
-  }
-  void DropRef() {
-    sys::SmartScopedLock<true> Lock(*ALMutex);
-    if (!AttributesLists.isConstructed())
-      return;
-    sys::cas_flag new_val = --RefCount;
-    if (new_val == 0)
-      delete this;
-  }
-
-  void Profile(FoldingSetNodeID &ID) const {
-    Profile(ID, Attrs);
-  }
-  static void Profile(FoldingSetNodeID &ID, ArrayRef<AttributeWithIndex> Attrs){
-    for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
-      ID.AddInteger(Attrs[i].Attrs.Raw());
-      ID.AddInteger(Attrs[i].Index);
-    }
-  }
-};
-
-} // end llvm namespace
-
-AttributeListImpl::~AttributeListImpl() {
-  // NOTE: Lock must be acquired by caller.
-  AttributesLists->RemoveNode(this);
-}
-
-AttrListPtr AttrListPtr::get(ArrayRef<AttributeWithIndex> Attrs) {
+AttrListPtr AttrListPtr::get(LLVMContext &C,
+                             ArrayRef<AttributeWithIndex> Attrs) {
   // If there are no attributes then return a null AttributesList pointer.
   if (Attrs.empty())
     return AttrListPtr();
@@ -425,49 +371,34 @@
 #endif
 
   // Otherwise, build a key to look up the existing attributes.
+  LLVMContextImpl *pImpl = C.pImpl;
   FoldingSetNodeID ID;
   AttributeListImpl::Profile(ID, Attrs);
-  void *InsertPos;
 
-  sys::SmartScopedLock<true> Lock(*ALMutex);
-
-  AttributeListImpl *PAL =
-    AttributesLists->FindNodeOrInsertPos(ID, InsertPos);
+  void *InsertPoint;
+  AttributeListImpl *PA = pImpl->AttrsLists.FindNodeOrInsertPos(ID,
+                                                                InsertPoint);
 
   // If we didn't find any existing attributes of the same shape then
   // create a new one and insert it.
-  if (!PAL) {
-    PAL = new AttributeListImpl(Attrs);
-    AttributesLists->InsertNode(PAL, InsertPos);
+  if (!PA) {
+    PA = new AttributeListImpl(Attrs);
+    pImpl->AttrsLists.InsertNode(PA, InsertPoint);
   }
 
   // Return the AttributesList that we found or created.
-  return AttrListPtr(PAL);
+  return AttrListPtr(PA);
 }
 
 //===----------------------------------------------------------------------===//
 // AttrListPtr Method Implementations
 //===----------------------------------------------------------------------===//
 
-AttrListPtr::AttrListPtr(AttributeListImpl *LI) : AttrList(LI) {
-  if (LI) LI->AddRef();
-}
-
-AttrListPtr::AttrListPtr(const AttrListPtr &P) : AttrList(P.AttrList) {
-  if (AttrList) AttrList->AddRef();
-}
-
 const AttrListPtr &AttrListPtr::operator=(const AttrListPtr &RHS) {
-  sys::SmartScopedLock<true> Lock(*ALMutex);
   if (AttrList == RHS.AttrList) return *this;
-  if (AttrList) AttrList->DropRef();
-  AttrList = RHS.AttrList;
-  if (AttrList) AttrList->AddRef();
-  return *this;
-}
 
-AttrListPtr::~AttrListPtr() {
-  if (AttrList) AttrList->DropRef();
+  AttrList = RHS.AttrList;
+  return *this;
 }
 
 /// getNumSlots - Return the number of slots used in this attribute list.
@@ -507,6 +438,7 @@
   for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
     if (Attrs[i].Attrs.hasAttribute(Attr))
       return true;
+
   return false;
 }
 
@@ -562,7 +494,7 @@
                        OldAttrList.begin()+i, OldAttrList.end());
   }
 
-  return get(NewAttrList);
+  return get(C, NewAttrList);
 }
 
 AttrListPtr AttrListPtr::removeAttr(LLVMContext &C, unsigned Idx,
@@ -601,7 +533,7 @@
   NewAttrList.insert(NewAttrList.end(),
                      OldAttrList.begin()+i, OldAttrList.end());
 
-  return get(NewAttrList);
+  return get(C, NewAttrList);
 }
 
 void AttrListPtr::dump() const {
diff --git a/llvm/lib/VMCore/AttributesImpl.h b/llvm/lib/VMCore/AttributesImpl.h
index b4a0f615..5c107e1 100644
--- a/llvm/lib/VMCore/AttributesImpl.h
+++ b/llvm/lib/VMCore/AttributesImpl.h
@@ -15,12 +15,11 @@
 #ifndef LLVM_ATTRIBUTESIMPL_H
 #define LLVM_ATTRIBUTESIMPL_H
 
+#include "llvm/Attributes.h"
 #include "llvm/ADT/FoldingSet.h"
 
 namespace llvm {
 
-class Attributes;
-
 class AttributesImpl : public FoldingSetNode {
   uint64_t Bits;                // FIXME: We will be expanding this.
 public:
@@ -46,6 +45,27 @@
   }
 };
 
+class AttributeListImpl : public FoldingSetNode {
+  // AttributesList is uniqued, these should not be publicly available.
+  void operator=(const AttributeListImpl &) LLVM_DELETED_FUNCTION;
+  AttributeListImpl(const AttributeListImpl &) LLVM_DELETED_FUNCTION;
+public:
+  SmallVector<AttributeWithIndex, 4> Attrs;
+
+  AttributeListImpl(ArrayRef<AttributeWithIndex> attrs)
+    : Attrs(attrs.begin(), attrs.end()) {}
+
+  void Profile(FoldingSetNodeID &ID) const {
+    Profile(ID, Attrs);
+  }
+  static void Profile(FoldingSetNodeID &ID, ArrayRef<AttributeWithIndex> Attrs){
+    for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
+      ID.AddInteger(Attrs[i].Attrs.Raw());
+      ID.AddInteger(Attrs[i].Index);
+    }
+  }
+};
+
 } // end llvm namespace
 
 #endif
diff --git a/llvm/lib/VMCore/LLVMContextImpl.cpp b/llvm/lib/VMCore/LLVMContextImpl.cpp
index 74247bd..d35d284 100644
--- a/llvm/lib/VMCore/LLVMContextImpl.cpp
+++ b/llvm/lib/VMCore/LLVMContextImpl.cpp
@@ -97,11 +97,18 @@
 
   // Destroy attributes.
   for (FoldingSetIterator<AttributesImpl> I = AttrsSet.begin(),
-         E = AttrsSet.end(); I != E;) {
+         E = AttrsSet.end(); I != E; ) {
     FoldingSetIterator<AttributesImpl> Elem = I++;
     delete &*Elem;
   }
 
+  // Destroy attribute lists.
+  for (FoldingSetIterator<AttributeListImpl> I = AttrsLists.begin(),
+         E = AttrsLists.end(); I != E; ) {
+    FoldingSetIterator<AttributeListImpl> Elem = I++;
+    delete &*Elem;
+  }
+
   // Destroy MDNodes.  ~MDNode can move and remove nodes between the MDNodeSet
   // and the NonUniquedMDNodes sets, so copy the values out first.
   SmallVector<MDNode*, 8> MDNodes;
diff --git a/llvm/lib/VMCore/LLVMContextImpl.h b/llvm/lib/VMCore/LLVMContextImpl.h
index ee31814..90cf424 100644
--- a/llvm/lib/VMCore/LLVMContextImpl.h
+++ b/llvm/lib/VMCore/LLVMContextImpl.h
@@ -256,7 +256,8 @@
   FPMapTy FPConstants;
 
   FoldingSet<AttributesImpl> AttrsSet;
-  
+  FoldingSet<AttributeListImpl> AttrsLists;
+
   StringMap<Value*> MDStringCache;
 
   FoldingSet<MDNode> MDNodeSet;