//===-- 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
#define LLVM_USE_H
#include "llvm/Support/Casting.h"
-#include "llvm/ADT/iterator"
+#include "llvm/ADT/iterator.h"
namespace llvm {
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);
Use *getNext() const { return Next; }
private:
- Use *Next, **Prev;
Value *Val;
- User *U;
+ Use *Next, **Prev;
+ void setPrev(Use **NewPrev) {
+ Prev = transferTag<fullStopTag>(Prev, NewPrev);
+ }
void addToList(Use **List) {
Next = *List;
- if (Next) Next->Prev = &Next;
- Prev = List;
+ if (Next) Next->setPrev(&Next);
+ setPrev(List);
*List = this;
}
void removeFromList() {
- *Prev = Next;
- if (Next) Next->Prev = Prev;
+ Use **StrippedPrev = stripTag<fullStopTag>(Prev);
+ *StrippedPrev = Next;
+ if (Next) Next->setPrev(StrippedPrev);
}
friend class Value;
typedef value_use_iterator<UserTy> _Self;
Use *U;
- value_use_iterator(Use *u) : U(u) {}
+ explicit value_use_iterator(Use *u) : U(u) {}
friend class Value;
public:
typedef typename super::reference reference;
value_use_iterator(const _Self &I) : U(I.U) {}
value_use_iterator() {}
- bool operator==(const _Self &x) const {
+ bool operator==(const _Self &x) const {
return U == x.U;
}
bool operator!=(const _Self &x) const {
return !operator==(x);
}
+ /// atEnd - return true if this iterator is equal to use_end() on the value.
+ bool atEnd() const { return U == 0; }
+
// Iterator traversal: forward iteration only
_Self &operator++() { // Preincrement
assert(U && "Cannot increment end iterator!");
U = U->getNext();
- return *this;
+ return *this;
}
_Self operator++(int) { // Postincrement
- _Self tmp = *this; ++*this; return tmp;
+ _Self tmp = *this; ++*this; return tmp;
}
- // Retrieve a reference to the current SCC
- UserTy *operator*() const {
- assert(U && "Cannot increment end iterator!");
+ // Retrieve a reference to the current User
+ UserTy *operator*() const {
+ assert(U && "Cannot dereference end iterator!");
return U->getUser();
}
UserTy *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;
+};
+
+
+template<> struct simplify_type<value_use_iterator<User> > {
+ typedef User* SimpleType;
+
+ static SimpleType getSimplifiedValue(const value_use_iterator<User> &Val) {
+ return *Val;
+ }
+};
+
+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
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