//===-- llvm/Use.h - Definition of the Use class ----------------*- C++ -*-===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This defines the Use class. The Use class represents the operand of an
#ifndef LLVM_USE_H
#define LLVM_USE_H
-#include "llvm/ADT/ilist"
+#include "llvm/Support/Casting.h"
+#include "llvm/ADT/iterator.h"
namespace llvm {
-template<typename NodeTy> struct ilist_traits;
class Value;
class User;
+//===----------------------------------------------------------------------===//
+// Generic Tagging Functions
+//===----------------------------------------------------------------------===//
+
+/// Tag - generic tag type for (at least 32 bit) pointers
+enum Tag { noTag, tagOne, tagTwo, tagThree };
+
+/// addTag - insert tag bits into an (untagged) pointer
+template <typename T, typename TAG>
+inline T *addTag(const T *P, TAG Tag) {
+ return reinterpret_cast<T*>(ptrdiff_t(P) | Tag);
+}
+
+/// stripTag - remove tag bits from a pointer,
+/// making it dereferencable
+template <ptrdiff_t MASK, typename T>
+inline T *stripTag(const T *P) {
+ return reinterpret_cast<T*>(ptrdiff_t(P) & ~MASK);
+}
+
+/// extractTag - extract tag bits from a pointer
+template <typename TAG, TAG MASK, typename T>
+inline TAG extractTag(const T *P) {
+ return TAG(ptrdiff_t(P) & MASK);
+}
+
+/// transferTag - transfer tag bits from a pointer,
+/// to an untagged pointer
+template <ptrdiff_t MASK, typename T>
+inline T *transferTag(const T *From, const T *To) {
+ return reinterpret_cast<T*>((ptrdiff_t(From) & MASK) | ptrdiff_t(To));
+}
+
+
//===----------------------------------------------------------------------===//
// Use Class
//===----------------------------------------------------------------------===//
// Use is here to make keeping the "use" list of a Value up-to-date really easy.
//
class Use {
-public:
+private:
+ /// init - specify Value and User
+ /// @deprecated in 2.4, will be removed soon
inline void init(Value *V, User *U);
+public:
+ /// swap - provide a fast substitute to std::swap<Use>
+ /// that also works with less standard-compliant compilers
+ void swap(Use &RHS);
+
+private:
+ /// Copy ctor - do not implement
+ Use(const Use &U);
- Use(Value *V, User *U) { init(V, U); }
- Use(const Use &U) { init(U.Val, U.U); }
- inline ~Use();
+ /// Destructor - Only for zap()
+ inline ~Use() {
+ if (Val) removeFromList();
+ }
- /// Default ctor - This leaves the Use completely unitialized. The only thing
+ /// Default ctor - This leaves the Use completely uninitialized. The only thing
/// that is valid to do with this use is to call the "init" method.
- inline Use() : Val(0) {}
+ inline Use() {}
+ enum PrevPtrTag { zeroDigitTag = noTag
+ , oneDigitTag = tagOne
+ , stopTag = tagTwo
+ , fullStopTag = tagThree };
+public:
operator Value*() const { return Val; }
Value *get() const { return Val; }
- User *getUser() const { return U; }
+ User *getUser() const;
+ const Use* getImpliedUser() const;
+ static Use *initTags(Use *Start, Use *Stop, ptrdiff_t Done = 0);
+ static void zap(Use *Start, const Use *Stop, bool del = false);
inline void set(Value *Val);
Value *operator->() { return Val; }
const Value *operator->() const { return Val; }
+ Use *getNext() const { return Next; }
private:
- // NOTE!! The Next/Prev fields MUST stay at the start of this structure. The
- // end-token for the ilist is allocated as JUST the next/prev pair to reduce
- // memory usage instead of allocating an entire Use.
- struct NextPrevPtrs {
- Use *Next, *Prev;
- } UseLinks;
-
Value *Val;
- User *U;
- friend struct ilist_traits<Use>;
-};
+ Use *Next, **Prev;
-template<>
-struct ilist_traits<Use> {
- static Use *getPrev(Use *N) { return N->UseLinks.Prev; }
- static Use *getNext(Use *N) { return N->UseLinks.Next; }
- static const Use *getPrev(const Use *N) { return N->UseLinks.Prev; }
- static const Use *getNext(const Use *N) { return N->UseLinks.Next; }
- static void setPrev(Use *N, Use *Prev) { N->UseLinks.Prev = Prev; }
- static void setNext(Use *N, Use *Next) { N->UseLinks.Next = Next; }
-
- /// createSentinal - this is used to create the end marker for the use list.
- /// Note that we only allocate a UseLinks structure, which is just enough to
- /// hold the next/prev pointers. This saves us 8 bytes of memory for every
- /// Value allocated.
- static Use *createSentinal() { return (Use*)new Use::NextPrevPtrs(); }
- static void destroySentinal(Use *S) { delete (Use::NextPrevPtrs*)S; }
-
- void addNodeToList(Use *NTy) {}
- void removeNodeFromList(Use *NTy) {}
- void transferNodesFromList(iplist<Use, ilist_traits> &L2,
- ilist_iterator<Use> first,
- ilist_iterator<Use> last) {}
-};
+ void setPrev(Use **NewPrev) {
+ Prev = transferTag<fullStopTag>(Prev, NewPrev);
+ }
+ void addToList(Use **List) {
+ Next = *List;
+ if (Next) Next->setPrev(&Next);
+ setPrev(List);
+ *List = this;
+ }
+ void removeFromList() {
+ Use **StrippedPrev = stripTag<fullStopTag>(Prev);
+ *StrippedPrev = Next;
+ if (Next) Next->setPrev(StrippedPrev);
+ }
+ friend class Value;
+};
+// simplify_type - Allow clients to treat uses just like values when using
+// casting operators.
template<> struct simplify_type<Use> {
typedef Value* SimpleType;
static SimpleType getSimplifiedValue(const Use &Val) {
}
};
-struct UseListIteratorWrapper : public iplist<Use>::iterator {
- typedef iplist<Use>::iterator Super;
- UseListIteratorWrapper() {}
- UseListIteratorWrapper(const Super &RHS) : Super(RHS) {}
- UseListIteratorWrapper &operator=(const Super &RHS) {
- Super::operator=(RHS);
- return *this;
- }
- inline User *operator*() const;
- User *operator->() const { return operator*(); }
+template<typename UserTy> // UserTy == 'User' or 'const User'
+class value_use_iterator : public forward_iterator<UserTy*, ptrdiff_t> {
+ typedef forward_iterator<UserTy*, ptrdiff_t> super;
+ typedef value_use_iterator<UserTy> _Self;
- UseListIteratorWrapper operator--() { return Super::operator--(); }
- UseListIteratorWrapper operator++() { return Super::operator++(); }
+ Use *U;
+ explicit value_use_iterator(Use *u) : U(u) {}
+ friend class Value;
+public:
+ typedef typename super::reference reference;
+ typedef typename super::pointer pointer;
- UseListIteratorWrapper operator--(int) { // postdecrement operators...
- UseListIteratorWrapper tmp = *this;
- --*this;
- return tmp;
+ value_use_iterator(const _Self &I) : U(I.U) {}
+ value_use_iterator() {}
+
+ bool operator==(const _Self &x) const {
+ return U == x.U;
}
- UseListIteratorWrapper operator++(int) { // postincrement operators...
- UseListIteratorWrapper tmp = *this;
- ++*this;
- return tmp;
+ bool operator!=(const _Self &x) const {
+ return !operator==(x);
}
-};
-struct UseListConstIteratorWrapper : public iplist<Use>::const_iterator {
- typedef iplist<Use>::const_iterator Super;
- UseListConstIteratorWrapper() {}
- UseListConstIteratorWrapper(const Super &RHS) : Super(RHS) {}
+ /// atEnd - return true if this iterator is equal to use_end() on the value.
+ bool atEnd() const { return U == 0; }
- // Allow conversion from non-const to const iterators
- UseListConstIteratorWrapper(const UseListIteratorWrapper &RHS) : Super(RHS) {}
- UseListConstIteratorWrapper(const iplist<Use>::iterator &RHS) : Super(RHS) {}
-
- UseListConstIteratorWrapper &operator=(const Super &RHS) {
- Super::operator=(RHS);
+ // Iterator traversal: forward iteration only
+ _Self &operator++() { // Preincrement
+ assert(U && "Cannot increment end iterator!");
+ U = U->getNext();
return *this;
}
+ _Self operator++(int) { // Postincrement
+ _Self tmp = *this; ++*this; return tmp;
+ }
+
+ // Retrieve a reference to the current User
+ UserTy *operator*() const {
+ assert(U && "Cannot dereference end iterator!");
+ return U->getUser();
+ }
+
+ UserTy *operator->() const { return operator*(); }
- inline const User *operator*() const;
- const User *operator->() const { return operator*(); }
+ Use &getUse() const { return *U; }
+
+ /// getOperandNo - Return the operand # of this use in its User. Defined in
+ /// User.h
+ ///
+ unsigned getOperandNo() const;
+};
- UseListConstIteratorWrapper operator--() { return Super::operator--(); }
- UseListConstIteratorWrapper operator++() { return Super::operator++(); }
- UseListConstIteratorWrapper operator--(int) { // postdecrement operators...
- UseListConstIteratorWrapper tmp = *this;
- --*this;
- return tmp;
+template<> struct simplify_type<value_use_iterator<User> > {
+ typedef User* SimpleType;
+
+ static SimpleType getSimplifiedValue(const value_use_iterator<User> &Val) {
+ return *Val;
}
- UseListConstIteratorWrapper operator++(int) { // postincrement operators...
- UseListConstIteratorWrapper tmp = *this;
- ++*this;
- return tmp;
+};
+
+template<> struct simplify_type<const value_use_iterator<User> >
+ : public simplify_type<value_use_iterator<User> > {};
+
+template<> struct simplify_type<value_use_iterator<const User> > {
+ typedef const User* SimpleType;
+
+ static SimpleType getSimplifiedValue(const
+ value_use_iterator<const User> &Val) {
+ return *Val;
}
};
+template<> struct simplify_type<const value_use_iterator<const User> >
+ : public simplify_type<value_use_iterator<const User> > {};
+
} // End llvm namespace
#endif