Fix a serious bug that would cause deadlock during abstract type refinement. The constant creation

gets involved, and we end up trying to recursively acquire a writer lock.  The fix for this is slightly horrible,
and involves passing a boolean "locked" parameter around in Constants.cpp, but it's better than having locked and
unlocked versions of most of the code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73790 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 469 insertions, 356 deletions

diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h
index d4949d1a0f..613e24ca15 100644
--- a/include/llvm/Constant.h
+++ b/include/llvm/Constant.h
@@ -61,7 +61,7 @@ protected:
 public:
   /// Static constructor to get a '0' constant of arbitrary type...
   ///
-  static Constant *getNullValue(const Type *Ty);
+  static Constant *getNullValue(const Type *Ty, bool locked = true);
 
   /// Static constructor to get a '-1' constant.  This supports integers and
   /// vectors.
@@ -107,7 +107,9 @@ public:
   /// available cached constants.  Implementations should call
   /// destroyConstantImpl as the last thing they do, to destroy all users and
   /// delete this.
-  virtual void destroyConstant() { assert(0 && "Not reached!"); }
+  virtual void destroyConstant(bool locked = true) {
+    assert(0 && "Not reached!");
+  }
 
   //// Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const Constant *) { return true; }
diff --git a/include/llvm/Constants.h b/include/llvm/Constants.h
index 52fff2020c..afaa208157 100644
--- a/include/llvm/Constants.h
+++ b/include/llvm/Constants.h
@@ -109,11 +109,13 @@ public:
   /// the type.
   /// @brief Get a ConstantInt for a specific value.
   static ConstantInt *get(const IntegerType *Ty,
-                          uint64_t V, bool isSigned = false);
+                          uint64_t V, bool isSigned = false,
+                          bool locked = true);
 
   /// If Ty is a vector type, return a Constant with a splat of the given
   /// value. Otherwise return a ConstantInt for the given value.
-  static Constant *get(const Type *Ty, uint64_t V, bool isSigned = false);
+  static Constant *get(const Type *Ty, uint64_t V,
+                       bool isSigned = false, bool locked = true);
 
   /// Return a ConstantInt with the specified value for the specified type. The
   /// value V will be canonicalized to a an unsigned APInt. Accessing it with
@@ -129,11 +131,11 @@ public:
 
   /// Return a ConstantInt with the specified value and an implied Type. The
   /// type is the integer type that corresponds to the bit width of the value.
-  static ConstantInt *get(const APInt &V);
+  static ConstantInt *get(const APInt &V, bool locked = true);
 
   /// If Ty is a vector type, return a Constant with a splat of the given
   /// value. Otherwise return a ConstantInt for the given value.
-  static Constant *get(const Type *Ty, const APInt &V);
+  static Constant *get(const Type *Ty, const APInt &V, bool locked = true);
 
   /// getType - Specialize the getType() method to always return an IntegerType,
   /// which reduces the amount of casting needed in parts of the compiler.
@@ -230,7 +232,7 @@ public:
   /// @returns the value for an integer constant of the given type that has all
   /// its bits set to true.
   /// @brief Get the all ones value
-  static ConstantInt *getAllOnesValue(const Type *Ty);
+  static ConstantInt *getAllOnesValue(const Type *Ty, bool locked = true);
 
   /// @brief Methods to support type inquiry through isa, cast, and dyn_cast.
   static inline bool classof(const ConstantInt *) { return true; }
@@ -259,13 +261,13 @@ protected:
   }
 public:
   /// get() - Static factory methods - Return objects of the specified value
-  static ConstantFP *get(const APFloat &V);
+  static ConstantFP *get(const APFloat &V, bool locked = true);
 
   /// get() - This returns a ConstantFP, or a vector containing a splat of a
   /// ConstantFP, for the specified value in the specified type.  This should
   /// only be used for simple constant values like 2.0/1.0 etc, that are
   /// known-valid both as host double and as the target format.
-  static Constant *get(const Type *Ty, double V);
+  static Constant *get(const Type *Ty, double V, bool locked = true);
 
   /// isValueValidForType - return true if Ty is big enough to represent V.
   static bool isValueValidForType(const Type *Ty, const APFloat& V);
@@ -321,13 +323,13 @@ protected:
 public:
   /// get() - static factory method for creating a null aggregate.  It is
   /// illegal to call this method with a non-aggregate type.
-  static ConstantAggregateZero *get(const Type *Ty);
+  static ConstantAggregateZero *get(const Type *Ty, bool locked = true);
 
   /// isNullValue - Return true if this is the value that would be returned by
   /// getNullValue.
   virtual bool isNullValue() const { return true; }
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   ///
@@ -349,9 +351,11 @@ protected:
   ConstantArray(const ArrayType *T, const std::vector<Constant*> &Val);
 public:
   /// get() - Static factory methods - Return objects of the specified value
-  static Constant *get(const ArrayType *T, const std::vector<Constant*> &);
+  static Constant *get(const ArrayType *T, const std::vector<Constant*> &,
+                       bool locked = true);
   static Constant *get(const ArrayType *T,
-                       Constant*const*Vals, unsigned NumVals) {
+                       Constant*const*Vals, unsigned NumVals,
+                       bool locked = true) {
     // FIXME: make this the primary ctor method.
     return get(T, std::vector<Constant*>(Vals, Vals+NumVals));
   }
@@ -362,7 +366,8 @@ public:
   /// of the array by one (you've been warned).  However, in some situations 
   /// this is not desired so if AddNull==false then the string is copied without
   /// null termination. 
-  static Constant *get(const std::string &Initializer, bool AddNull = true);
+  static Constant *get(const std::string &Initializer,
+                       bool AddNull = true, bool locked = true);
 
   /// Transparently provide more efficient getOperand methods.
   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
@@ -395,7 +400,7 @@ public:
   /// created as ConstantAggregateZero objects.
   virtual bool isNullValue() const { return false; }
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -423,12 +428,14 @@ protected:
 public:
   /// get() - Static factory methods - Return objects of the specified value
   ///
-  static Constant *get(const StructType *T, const std::vector<Constant*> &V);
-  static Constant *get(const std::vector<Constant*> &V, bool Packed = false);
+  static Constant *get(const StructType *T, const std::vector<Constant*> &V,
+                       bool locked = true);
+  static Constant *get(const std::vector<Constant*> &V, bool Packed = false, 
+                       bool locked = true);
   static Constant *get(Constant*const* Vals, unsigned NumVals,
-                       bool Packed = false) {
+                       bool Packed = false, bool locked = true) {
     // FIXME: make this the primary ctor method.
-    return get(std::vector<Constant*>(Vals, Vals+NumVals), Packed);
+    return get(std::vector<Constant*>(Vals, Vals+NumVals), Packed, locked);
   }
   
   /// Transparently provide more efficient getOperand methods.
@@ -447,7 +454,7 @@ public:
     return false;
   }
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -474,11 +481,13 @@ protected:
   ConstantVector(const VectorType *T, const std::vector<Constant*> &Val);
 public:
   /// get() - Static factory methods - Return objects of the specified value
-  static Constant *get(const VectorType *T, const std::vector<Constant*> &);
-  static Constant *get(const std::vector<Constant*> &V);
-  static Constant *get(Constant*const* Vals, unsigned NumVals) {
+  static Constant *get(const VectorType *T, const std::vector<Constant*> &,
+                       bool locked = true);
+  static Constant *get(const std::vector<Constant*> &V, bool locked = true);
+  static Constant *get(Constant*const* Vals, unsigned NumVals,
+                       bool locked = true) {
     // FIXME: make this the primary ctor method.
-    return get(std::vector<Constant*>(Vals, Vals+NumVals));
+    return get(std::vector<Constant*>(Vals, Vals+NumVals), locked);
   }
   
   /// Transparently provide more efficient getOperand methods.
@@ -494,7 +503,8 @@ public:
   /// @returns the value for a vector integer constant of the given type that
   /// has all its bits set to true.
   /// @brief Get the all ones value
-  static ConstantVector *getAllOnesValue(const VectorType *Ty);
+  static ConstantVector *getAllOnesValue(const VectorType *Ty,
+                                         bool locked = true);
   
   /// isNullValue - Return true if this is the value that would be returned by
   /// getNullValue.  This always returns false because zero vectors are always
@@ -511,7 +521,7 @@ public:
   /// elements have the same value, return that value. Otherwise return NULL.
   Constant *getSplatValue();
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -546,13 +556,13 @@ protected:
   }
 public:
   /// get() - Static factory methods - Return objects of the specified value
-  static ConstantPointerNull *get(const PointerType *T);
+  static ConstantPointerNull *get(const PointerType *T, bool locked = true);
 
   /// isNullValue - Return true if this is the value that would be returned by
   /// getNullValue.
   virtual bool isNullValue() const { return true; }
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
 
   /// getType - Specialize the getType() method to always return an PointerType,
   /// which reduces the amount of casting needed in parts of the compiler.
@@ -590,13 +600,14 @@ protected:
   // These private methods are used by the type resolution code to create
   // ConstantExprs in intermediate forms.
   static Constant *getTy(const Type *Ty, unsigned Opcode,
-                         Constant *C1, Constant *C2);
+                         Constant *C1, Constant *C2, bool locked = true);
   static Constant *getCompareTy(unsigned short pred, Constant *C1,
                                 Constant *C2);
-  static Constant *getSelectTy(const Type *Ty,
-                               Constant *C1, Constant *C2, Constant *C3);
+  static Constant *getSelectTy(const Type *Ty, Constant *C1, Constant *C2,
+                               Constant *C3, bool locked = true);
   static Constant *getGetElementPtrTy(const Type *Ty, Constant *C,
-                                      Value* const *Idxs, unsigned NumIdxs);
+                                      Value* const *Idxs, unsigned NumIdxs,
+                                      bool locked = true);
   static Constant *getExtractElementTy(const Type *Ty, Constant *Val,
                                        Constant *Idx);
   static Constant *getInsertElementTy(const Type *Ty, Constant *Val,
@@ -617,18 +628,18 @@ public:
 
   /// Cast constant expr
   ///
-  static Constant *getTrunc   (Constant *C, const Type *Ty);
-  static Constant *getSExt    (Constant *C, const Type *Ty);
-  static Constant *getZExt    (Constant *C, const Type *Ty);
-  static Constant *getFPTrunc (Constant *C, const Type *Ty);
-  static Constant *getFPExtend(Constant *C, const Type *Ty);
-  static Constant *getUIToFP  (Constant *C, const Type *Ty);
-  static Constant *getSIToFP  (Constant *C, const Type *Ty);
-  static Constant *getFPToUI  (Constant *C, const Type *Ty);
-  static Constant *getFPToSI  (Constant *C, const Type *Ty);
-  static Constant *getPtrToInt(Constant *C, const Type *Ty);
-  static Constant *getIntToPtr(Constant *C, const Type *Ty);
-  static Constant *getBitCast (Constant *C, const Type *Ty);
+  static Constant *getTrunc   (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getSExt    (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getZExt    (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getFPTrunc (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getFPExtend(Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getUIToFP  (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getSIToFP  (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getFPToUI  (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getFPToSI  (Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getPtrToInt(Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getIntToPtr(Constant *C, const Type *Ty, bool locked = true);
+  static Constant *getBitCast (Constant *C, const Type *Ty, bool locked = true);
 
   /// Transparently provide more efficient getOperand methods.
   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
@@ -638,7 +649,8 @@ public:
   static Constant *getCast(
     unsigned ops,  ///< The opcode for the conversion
     Constant *C,   ///< The constant to be converted
-    const Type *Ty ///< The type to which the constant is converted
+    const Type *Ty, ///< The type to which the constant is converted
+    bool locked = true
   );
 
   // @brief Create a ZExt or BitCast cast constant expression
@@ -650,7 +662,8 @@ public:
   // @brief Create a SExt or BitCast cast constant expression 
   static Constant *getSExtOrBitCast(
     Constant *C,   ///< The constant to sext or bitcast
-    const Type *Ty ///< The type to sext or bitcast C to
+    const Type *Ty, ///< The type to sext or bitcast C to
+    bool locked = true
   );
 
   // @brief Create a Trunc or BitCast cast constant expression
@@ -662,7 +675,8 @@ public:
   /// @brief Create a BitCast or a PtrToInt cast constant expression
   static Constant *getPointerCast(
     Constant *C,   ///< The pointer value to be casted (operand 0)
-    const Type *Ty ///< The type to which cast should be made
+    const Type *Ty, ///< The type to which cast should be made
+    bool locked = true
   );
 
   /// @brief Create a ZExt, Bitcast or Trunc for integer -> integer casts
@@ -708,7 +722,8 @@ public:
   /// ConstantExpr::get - Return a binary or shift operator constant expression,
   /// folding if possible.
   ///
-  static Constant *get(unsigned Opcode, Constant *C1, Constant *C2);
+  static Constant *get(unsigned Opcode, Constant *C1, Constant *C2,
+                       bool locked = true);
 
   /// @brief Return an ICmp, FCmp, VICmp, or VFCmp comparison operator constant
   /// expression.
@@ -720,36 +735,38 @@ public:
   static Constant *getNeg(Constant *C);
   static Constant *getFNeg(Constant *C);
   static Constant *getNot(Constant *C);
-  static Constant *getAdd(Constant *C1, Constant *C2);
-  static Constant *getFAdd(Constant *C1, Constant *C2);
-  static Constant *getSub(Constant *C1, Constant *C2);
-  static Constant *getFSub(Constant *C1, Constant *C2);
-  static Constant *getMul(Constant *C1, Constant *C2);
-  static Constant *getFMul(Constant *C1, Constant *C2);
-  static Constant *getUDiv(Constant *C1, Constant *C2);
-  static Constant *getSDiv(Constant *C1, Constant *C2);
-  static Constant *getFDiv(Constant *C1, Constant *C2);
-  static Constant *getURem(Constant *C1, Constant *C2); // unsigned rem
-  static Constant *getSRem(Constant *C1, Constant *C2); // signed rem
-  static Constant *getFRem(Constant *C1, Constant *C2);
-  static Constant *getAnd(Constant *C1, Constant *C2);
-  static Constant *getOr(Constant *C1, Constant *C2);
-  static Constant *getXor(Constant *C1, Constant *C2);
+  static Constant *getAdd(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getFAdd(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getSub(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getFSub(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getMul(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getFMul(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getUDiv(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getSDiv(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getFDiv(Constant *C1, Constant *C2, bool locked = true);
+  // unsigned rem
+  static Constant *getURem(Constant *C1, Constant *C2, bool locked = true); 
+  // signed rem
+  static Constant *getSRem(Constant *C1, Constant *C2, bool locked = true); 
+  static Constant *getFRem(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getAnd(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getOr(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getXor(Constant *C1, Constant *C2, bool locked = true);
   static Constant *getICmp(unsigned short pred, Constant *LHS, Constant *RHS);
   static Constant *getFCmp(unsigned short pred, Constant *LHS, Constant *RHS);
   static Constant *getVICmp(unsigned short pred, Constant *LHS, Constant *RHS);
   static Constant *getVFCmp(unsigned short pred, Constant *LHS, Constant *RHS);
-  static Constant *getShl(Constant *C1, Constant *C2);
-  static Constant *getLShr(Constant *C1, Constant *C2);
-  static Constant *getAShr(Constant *C1, Constant *C2);
+  static Constant *getShl(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getLShr(Constant *C1, Constant *C2, bool locked = true);
+  static Constant *getAShr(Constant *C1, Constant *C2, bool locked = true);
 
   /// Getelementptr form.  std::vector<Value*> is only accepted for convenience:
   /// all elements must be Constant's.
   ///
-  static Constant *getGetElementPtr(Constant *C,
-                                    Constant* const *IdxList, unsigned NumIdx);
-  static Constant *getGetElementPtr(Constant *C,
-                                    Value* const *IdxList, unsigned NumIdx);
+  static Constant *getGetElementPtr(Constant *C, Constant* const *IdxList,
+                                    unsigned NumIdx, bool locked = true);
+  static Constant *getGetElementPtr(Constant *C, Value* const *IdxList,
+                                    unsigned NumIdx, bool locked = true);
   
   static Constant *getExtractElement(Constant *Vec, Constant *Idx);
   static Constant *getInsertElement(Constant *Vec, Constant *Elt,Constant *Idx);
@@ -794,7 +811,7 @@ public:
   }
   Constant *getWithOperands(Constant* const *Ops, unsigned NumOps) const;
   
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -831,13 +848,13 @@ public:
   /// get() - Static factory methods - Return an 'undef' object of the specified
   /// type.
   ///
-  static UndefValue *get(const Type *T);
+  static UndefValue *get(const Type *T, bool locked = true);
 
   /// isNullValue - Return true if this is the value that would be returned by
   /// getNullValue.
   virtual bool isNullValue() const { return false; }
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const UndefValue *) { return true; }
@@ -864,7 +881,8 @@ protected:
 public:
   /// get() - Static factory methods - Return objects of the specified value.
   ///
-  static MDString *get(const char *StrBegin, const char *StrEnd);
+  static MDString *get(const char *StrBegin, const char *StrEnd, 
+                       bool locked = true);
 
   /// size() - The length of this string.
   ///
@@ -891,7 +909,7 @@ public:
     return false;
   }
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const MDString *) { return true; }
diff --git a/include/llvm/GlobalValue.h b/include/llvm/GlobalValue.h
index 3b7f67d5d0..934d082914 100644
--- a/include/llvm/GlobalValue.h
+++ b/include/llvm/GlobalValue.h
@@ -172,7 +172,7 @@ public:
   virtual bool isNullValue() const { return false; }
 
   /// Override from Constant class.
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
 
   /// isDeclaration - Return true if the primary definition of this global 
   /// value is outside of the current translation unit...
diff --git a/include/llvm/MDNode.h b/include/llvm/MDNode.h
index d632e4ea4a..06b71776e0 100644
--- a/include/llvm/MDNode.h
+++ b/include/llvm/MDNode.h
@@ -78,7 +78,7 @@ public:
 
   /// get() - Static factory methods - Return objects of the specified value.
   ///
-  static MDNode *get(Value*const* Vals, unsigned NumVals);
+  static MDNode *get(Value*const* Vals, unsigned NumVals, bool locked = true);
 
   Value *getElement(unsigned i) const {
     return Node[i];
@@ -117,7 +117,7 @@ public:
   /// duplicates
   void Profile(FoldingSetNodeID &ID) const;
 
-  virtual void destroyConstant();
+  virtual void destroyConstant(bool locked = true);
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
     assert(0 && "This should never be called because MDNodes have no ops");
     abort();
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 6c392145a5..4b2a3f25db 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -40,7 +40,8 @@ using namespace llvm;
 /// specified vector type.  At this point, we know that the elements of the
 /// input vector constant are all simple integer or FP values.
 static Constant *BitCastConstantVector(ConstantVector *CV,
-                                       const VectorType *DstTy) {
+                                       const VectorType *DstTy,
+                                       bool locked) {
   // If this cast changes element count then we can't handle it here:
   // doing so requires endianness information.  This should be handled by
   // Analysis/ConstantFolding.cpp
@@ -60,7 +61,7 @@ static Constant *BitCastConstantVector(ConstantVector *CV,
   const Type *DstEltTy = DstTy->getElementType();
   for (unsigned i = 0; i != NumElts; ++i)
     Result.push_back(ConstantExpr::getBitCast(CV->getOperand(i), DstEltTy));
-  return ConstantVector::get(Result);
+  return ConstantVector::get(Result, locked);
 }
 
 /// This function determines which opcode to use to fold two constant cast 
@@ -88,7 +89,8 @@ foldConstantCastPair(
                                         Type::Int64Ty);
 }
 
-static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
+static Constant *FoldBitCast(Constant *V, const Type *DestTy,
+                             bool locked = true) {
   const Type *SrcTy = V->getType();
   if (SrcTy == DestTy)
     return V; // no-op cast
@@ -99,7 +101,7 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
     if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy))
       if (PTy->getAddressSpace() == DPTy->getAddressSpace()) {
         SmallVector<Value*, 8> IdxList;
-        IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
+        IdxList.push_back(Constant::getNullValue(Type::Int32Ty, locked));
         const Type *ElTy = PTy->getElementType();
         while (ElTy != DPTy->getElementType()) {
           if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
@@ -117,7 +119,8 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
         }
         
         if (ElTy == DPTy->getElementType())
-          return ConstantExpr::getGetElementPtr(V, &IdxList[0], IdxList.size());
+          return ConstantExpr::getGetElementPtr(V, &IdxList[0],
+                                                IdxList.size(), locked);
       }
   
   // Handle casts from one vector constant to another.  We know that the src 
@@ -129,23 +132,24 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
       SrcTy = NULL;
       // First, check for null.  Undef is already handled.
       if (isa<ConstantAggregateZero>(V))
-        return Constant::getNullValue(DestTy);
+        return Constant::getNullValue(DestTy, locked);
       
       if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
-        return BitCastConstantVector(CV, DestPTy);
+        return BitCastConstantVector(CV, DestPTy, locked);
     }
 
     // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
     // This allows for other simplifications (although some of them
     // can only be handled by Analysis/ConstantFolding.cpp).
     if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
-      return ConstantExpr::getBitCast(ConstantVector::get(&V, 1), DestPTy);
+      return ConstantExpr::getBitCast(ConstantVector::get(&V, 1, locked), 
+                                      DestPTy, locked);
   }
   
   // Finally, implement bitcast folding now.   The code below doesn't handle
   // bitcast right.
   if (isa<ConstantPointerNull>(V))  // ptr->ptr cast.
-    return ConstantPointerNull::get(cast<PointerType>(DestTy));
+    return ConstantPointerNull::get(cast<PointerType>(DestTy), locked);
   
   // Handle integral constant input.
   if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
@@ -156,7 +160,7 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
 
     if (DestTy->isFloatingPoint())
       return ConstantFP::get(APFloat(CI->getValue(),
-                                     DestTy != Type::PPC_FP128Ty));
+                                     DestTy != Type::PPC_FP128Ty), locked);
 
     // Otherwise, can't fold this (vector?)
     return 0;
@@ -165,22 +169,22 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
   // Handle ConstantFP input.
   if (const ConstantFP *FP = dyn_cast<ConstantFP>(V))
     // FP -> Integral.
-    return ConstantInt::get(FP->getValueAPF().bitcastToAPInt());
+    return ConstantInt::get(FP->getValueAPF().bitcastToAPInt(), locked);
 
   return 0;
 }
 
 
 Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
-                                            const Type *DestTy) {
+                                            const Type *DestTy, bool locked) {
   if (isa<UndefValue>(V)) {
     // zext(undef) = 0, because the top bits will be zero.
     // sext(undef) = 0, because the top bits will all be the same.
     // [us]itofp(undef) = 0, because the result value is bounded.
     if (opc == Instruction::ZExt || opc == Instruction::SExt ||
         opc == Instruction::UIToFP || opc == Instruction::SIToFP)
-      return Constant::getNullValue(DestTy);
-    return UndefValue::get(DestTy);
+      return Constant::getNullValue(DestTy, locked);
+    return UndefValue::get(DestTy, locked);
   }
   // No compile-time operations on this type yet.
   if (V->getType() == Type::PPC_FP128Ty || DestTy == Type::PPC_FP128Ty)
@@ -192,7 +196,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
     if (CE->isCast()) {
       // Try hard to fold cast of cast because they are often eliminable.
       if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
-        return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
+        return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy, locked);
     } else if (CE->getOpcode() == Instruction::GetElementPtr) {
       // If all of the indexes in the GEP are null values, there is no pointer
       // adjustment going on.  We might as well cast the source pointer.
@@ -204,7 +208,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
         }
       if (isAllNull)
         // This is casting one pointer type to another, always BitCast
-        return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
+        return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy, locked);
     }
   }
 
@@ -220,8 +224,8 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
       const Type *DstEltTy = DestVecTy->getElementType();
       for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
         res.push_back(ConstantExpr::getCast(opc,
-                                            CV->getOperand(i), DstEltTy));
-      return ConstantVector::get(DestVecTy, res);
+                                        CV->getOperand(i), DstEltTy, locked));
+      return ConstantVector::get(DestVecTy, res, locked);
     }
 
   // We actually have to do a cast now. Perform the cast according to the
@@ -238,7 +242,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
                   DestTy == Type::FP128Ty ? APFloat::IEEEquad :
                   APFloat::Bogus,
                   APFloat::rmNearestTiesToEven, &ignored);
-      return ConstantFP::get(Val);
+      return ConstantFP::get(Val, locked);
     }
     return 0; // Can't fold.
   case Instruction::FPToUI: 
@@ -251,16 +255,16 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
       (void) V.convertToInteger(x, DestBitWidth, opc==Instruction::FPToSI,
                                 APFloat::rmTowardZero, &ignored);
       APInt Val(DestBitWidth, 2, x);
-      return ConstantInt::get(Val);
+      return ConstantInt::get(Val, locked);
     }
     return 0; // Can't fold.
   case Instruction::IntToPtr:   //always treated as unsigned
     if (V->isNullValue())       // Is it an integral null value?
-      return ConstantPointerNull::get(cast<PointerType>(DestTy));
+      return ConstantPointerNull::get(cast<PointerType>(DestTy), locked);
     return 0;                   // Other pointer types cannot be casted
   case Instruction::PtrToInt:   // always treated as unsigned
     if (V->isNullValue())       // is it a null pointer value?
-      return ConstantInt::get(DestTy, 0);
+      return ConstantInt::get(DestTy, 0, locked);
     return 0;                   // Other pointer types cannot be casted
   case Instruction::UIToFP:
   case Instruction::SIToFP:
@@ -272,7 +276,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
       (void)apf.convertFromAPInt(api, 
                                  opc==Instruction::SIToFP,
                                  APFloat::rmNearestTiesToEven);
-      return ConstantFP::get(apf);
+      return ConstantFP::get(apf, locked);
     }
     return 0;
   case Instruction::ZExt:
@@ -280,7 +284,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
       uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
       APInt Result(CI->getValue());
       Result.zext(BitWidth);
-      return ConstantInt::get(Result);
+      return ConstantInt::get(Result, locked);
     }
     return 0;
   case Instruction::SExt:
@@ -288,7 +292,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
       uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
       APInt Result(CI->getValue());
       Result.sext(BitWidth);
-      return ConstantInt::get(Result);
+      return ConstantInt::get(Result, locked);
     }
     return 0;
   case Instruction::Trunc:
@@ -296,11 +300,11 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
       uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
       APInt Result(CI->getValue());
       Result.trunc(BitWidth);
-      return ConstantInt::get(Result);
+      return ConstantInt::get(Result, locked);
     }
     return 0;
   case Instruction::BitCast:
-    return FoldBitCast(const_cast<Constant*>(V), DestTy);
+    return FoldBitCast(const_cast<Constant*>(V), DestTy, locked);
   default:
     assert(!"Invalid CE CastInst opcode");
     break;
@@ -312,7 +316,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
 
 Constant *llvm::ConstantFoldSelectInstruction(const Constant *Cond,
                                               const Constant *V1,
-                                              const Constant *V2) {
+                                              const Constant *V2, bool locked) {
   if (const ConstantInt *CB = dyn_cast<ConstantInt>(Cond))
     return const_cast<Constant*>(CB->getZExtValue() ? V1 : V2);
 
@@ -566,21 +570,22 @@ Constant *llvm::ConstantFoldInsertValueInstruction(const Constant *Agg,
 static Constant *EvalVectorOp(const ConstantVector *V1, 
                               const ConstantVector *V2,
                               const VectorType *VTy,
-                              Constant *(*FP)(Constant*, Constant*)) {
+                              Constant *(*FP)(Constant*, Constant*, bool)) {
   std::vector<Constant*> Res;
   const Type *EltTy = VTy->getElementType();
   for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
     const Constant *C1 = V1 ? V1->getOperand(i) : Constant::getNullValue(EltTy);
     const Constant *C2 = V2 ? V2->getOperand(i) : Constant::getNullValue(EltTy);
     Res.push_back(FP(const_cast<Constant*>(C1),
-                     const_cast<Constant*>(C2)));
+                     const_cast<Constant*>(C2), true));
   }
   return ConstantVector::get(Res);
 }
 
 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
                                               const Constant *C1,
-                                              const Constant *C2) {
+                                              const Constant *C2,
+                                              bool locked) {
   // No compile-time operations on this type yet.
   if (C1->getType() == Type::PPC_FP128Ty)
     return 0;
@@ -592,29 +597,29 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
       if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
         // Handle undef ^ undef -> 0 special case. This is a common
         // idiom (misuse).
-        return Constant::getNullValue(C1->getType());
+        return Constant::getNullValue(C1->getType(), locked);
       // Fallthrough
     case Instruction::Add:
     case Instruction::Sub:
-      return UndefValue::get(C1->getType());
+      return UndefValue::get(C1->getType(), locked);
     case Instruction::Mul:
     case Instruction::And:
-      return Constant::getNullValue(C1->getType());
+      return Constant::getNullValue(C1->getType(), locked);
     case Instruction::UDiv:
     case Instruction::SDiv:
     case Instruction::URem:
     case Instruction::SRem:
       if (!isa<UndefValue>(C2))                    // undef / X -> 0
-        return Constant::getNullValue(C1->getType());
+        return Constant::getNullValue(C1->getType(), locked);
       return const_cast<Constant*>(C2);            // X / undef -> undef
     case Instruction::Or:                          // X | undef -> -1
       if (const VectorType *PTy = dyn_cast<VectorType>(C1->getType()))
-        return ConstantVector::getAllOnesValue(PTy);
-      return ConstantInt::getAllOnesValue(C1->getType());
+        return ConstantVector::getAllOnesValue(PTy, locked);
+      return ConstantInt::getAllOnesValue(C1->getType(), locked);
     case Instruction::LShr:
       if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
         return const_cast<Constant*>(C1);           // undef lshr undef -> undef
-      return Constant::getNullValue(C1->getType()); // X lshr undef -> 0
+      return Constant::getNullValue(C1->getType(), locked); // X lshr undef -> 0
                                                     // undef lshr X -> 0
     case Instruction::AShr:
       if (!isa<UndefValue>(C2))
@@ -625,7 +630,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
         return const_cast<Constant*>(C1);           // X ashr undef --> X
     case Instruction::Shl:
       // undef << X -> 0   or   X << undef -> 0
-      return Constant::getNullValue(C1->getType());
+      return Constant::getNullValue(C1->getType(), locked);
     }
   }
 
@@ -1572,7 +1577,7 @@ Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
 
 Constant *llvm::ConstantFoldGetElementPtr(const Constant *C,
                                           Constant* const *Idxs,
-                                          unsigned NumIdx) {
+                                          unsigned NumIdx, bool locked) {
   if (NumIdx == 0 ||
       (NumIdx == 1 && Idxs[0]->isNullValue()))
     return const_cast<Constant*>(C);
@@ -1583,7 +1588,8 @@ Constant *llvm::ConstantFoldGetElementPtr(const Constant *C,
                                                        (Value **)Idxs,
                                                        (Value **)Idxs+NumIdx);
     assert(Ty != 0 && "Invalid indices for GEP!");
-    return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
+    return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()), 
+                           locked);