#ifndef LLVM_SUPPORT_VALUEHANDLE_H
#define LLVM_SUPPORT_VALUEHANDLE_H
+#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/Value.h"
/// fully general Callback version does have a vtable.
enum HandleBaseKind {
Assert,
- Weak,
- Callback
+ Callback,
+ Tracking,
+ Weak
};
private:
-
+
PointerIntPair<ValueHandleBase**, 2, HandleBaseKind> PrevPair;
ValueHandleBase *Next;
Value *VP;
+
+ explicit ValueHandleBase(const ValueHandleBase&); // DO NOT IMPLEMENT.
public:
explicit ValueHandleBase(HandleBaseKind Kind)
: PrevPair(0, Kind), Next(0), VP(0) {}
ValueHandleBase(HandleBaseKind Kind, Value *V)
: PrevPair(0, Kind), Next(0), VP(V) {
- if (V)
+ if (isValid(VP))
AddToUseList();
}
ValueHandleBase(HandleBaseKind Kind, const ValueHandleBase &RHS)
: PrevPair(0, Kind), Next(0), VP(RHS.VP) {
- if (VP)
+ if (isValid(VP))
AddToExistingUseList(RHS.getPrevPtr());
}
~ValueHandleBase() {
- if (VP)
- RemoveFromUseList();
+ if (isValid(VP))
+ RemoveFromUseList();
}
-
+
Value *operator=(Value *RHS) {
if (VP == RHS) return RHS;
- if (VP) RemoveFromUseList();
+ if (isValid(VP)) RemoveFromUseList();
VP = RHS;
- if (VP) AddToUseList();
+ if (isValid(VP)) AddToUseList();
return RHS;
}
Value *operator=(const ValueHandleBase &RHS) {
if (VP == RHS.VP) return RHS.VP;
- if (VP) RemoveFromUseList();
+ if (isValid(VP)) RemoveFromUseList();
VP = RHS.VP;
- if (VP) AddToExistingUseList(RHS.getPrevPtr());
+ if (isValid(VP)) AddToExistingUseList(RHS.getPrevPtr());
return VP;
}
-
+
Value *operator->() const { return getValPtr(); }
Value &operator*() const { return *getValPtr(); }
protected:
Value *getValPtr() const { return VP; }
+ static bool isValid(Value *V) {
+ return V &&
+ V != DenseMapInfo<Value *>::getEmptyKey() &&
+ V != DenseMapInfo<Value *>::getTombstoneKey();
+ }
+
private:
// Callbacks made from Value.
static void ValueIsDeleted(Value *V);
static void ValueIsRAUWd(Value *Old, Value *New);
-
+
// Internal implementation details.
ValueHandleBase **getPrevPtr() const { return PrevPair.getPointer(); }
HandleBaseKind getKind() const { return PrevPair.getInt(); }
void setPrevPtr(ValueHandleBase **Ptr) { PrevPair.setPointer(Ptr); }
-
- /// AddToUseList - Add this ValueHandle to the use list for VP, where List is
- /// known to point into the existing use list.
+
+ /// AddToExistingUseList - Add this ValueHandle to the use list for VP, where
+ /// List is the address of either the head of the list or a Next node within
+ /// the existing use list.
void AddToExistingUseList(ValueHandleBase **List);
-
+
+ /// AddToExistingUseListAfter - Add this ValueHandle to the use list after
+ /// Node.
+ void AddToExistingUseListAfter(ValueHandleBase *Node);
+
/// AddToUseList - Add this ValueHandle to the use list for VP.
void AddToUseList();
/// RemoveFromUseList - Remove this ValueHandle from its current use list.
void RemoveFromUseList();
};
-
+
/// WeakVH - This is a value handle that tries hard to point to a Value, even
/// across RAUW operations, but will null itself out if the value is destroyed.
/// this is useful for advisory sorts of information, but should not be used as
WeakVH(const WeakVH &RHS)
: ValueHandleBase(Weak, RHS) {}
+ Value *operator=(Value *RHS) {
+ return ValueHandleBase::operator=(RHS);
+ }
+ Value *operator=(const ValueHandleBase &RHS) {
+ return ValueHandleBase::operator=(RHS);
+ }
+
operator Value*() const {
return getValPtr();
}
-};
-
+};
+
+// Specialize simplify_type to allow WeakVH to participate in
+// dyn_cast, isa, etc.
+template<typename From> struct simplify_type;
+template<> struct simplify_type<const WeakVH> {
+ typedef Value* SimpleType;
+ static SimpleType getSimplifiedValue(const WeakVH &WVH) {
+ return static_cast<Value *>(WVH);
+ }
+};
+template<> struct simplify_type<WeakVH> : public simplify_type<const WeakVH> {};
+
/// AssertingVH - This is a Value Handle that points to a value and asserts out
/// if the value is destroyed while the handle is still live. This is very
/// useful for catching dangling pointer bugs and other things which can be
/// AssertingVH's as it moves. This is required because in non-assert mode this
/// class turns into a trivial wrapper around a pointer.
template <typename ValueTy>
-class AssertingVH
+class AssertingVH
#ifndef NDEBUG
: public ValueHandleBase
#endif
return static_cast<ValueTy*>(ValueHandleBase::getValPtr());
}
void setValPtr(ValueTy *P) {
- ValueHandleBase::operator=(P);
+ ValueHandleBase::operator=(GetAsValue(P));
}
#else
ValueTy *ThePtr;
void setValPtr(ValueTy *P) { ThePtr = P; }
#endif
+ // Convert a ValueTy*, which may be const, to the type the base
+ // class expects.
+ static Value *GetAsValue(Value *V) { return V; }
+ static Value *GetAsValue(const Value *V) { return const_cast<Value*>(V); }
+
public:
#ifndef NDEBUG
AssertingVH() : ValueHandleBase(Assert) {}
- AssertingVH(ValueTy *P) : ValueHandleBase(Assert, P) {}
+ AssertingVH(ValueTy *P) : ValueHandleBase(Assert, GetAsValue(P)) {}
AssertingVH(const AssertingVH &RHS) : ValueHandleBase(Assert, RHS) {}
#else
AssertingVH() : ThePtr(0) {}
setValPtr(RHS);
return getValPtr();
}
- ValueTy *operator=(AssertingVH<ValueTy> &RHS) {
+ ValueTy *operator=(const AssertingVH<ValueTy> &RHS) {
setValPtr(RHS.getValPtr());
return getValPtr();
}
ValueTy &operator*() const { return *getValPtr(); }
};
+// Specialize simplify_type to allow AssertingVH to participate in
+// dyn_cast, isa, etc.
+template<typename From> struct simplify_type;
+template<> struct simplify_type<const AssertingVH<Value> > {
+ typedef Value* SimpleType;
+ static SimpleType getSimplifiedValue(const AssertingVH<Value> &AVH) {
+ return static_cast<Value *>(AVH);
+ }
+};
+template<> struct simplify_type<AssertingVH<Value> >
+ : public simplify_type<const AssertingVH<Value> > {};
+
+// Specialize DenseMapInfo to allow AssertingVH to participate in DenseMap.
+template<typename T>
+struct DenseMapInfo<AssertingVH<T> > {
+ typedef DenseMapInfo<T*> PointerInfo;
+ static inline AssertingVH<T> getEmptyKey() {
+ return AssertingVH<T>(PointerInfo::getEmptyKey());
+ }
+ static inline T* getTombstoneKey() {
+ return AssertingVH<T>(PointerInfo::getTombstoneKey());
+ }
+ static unsigned getHashValue(const AssertingVH<T> &Val) {
+ return PointerInfo::getHashValue(Val);
+ }
+ static bool isEqual(const AssertingVH<T> &LHS, const AssertingVH<T> &RHS) {
+ return LHS == RHS;
+ }
+};
+
+template <typename T>
+struct isPodLike<AssertingVH<T> > {
+#ifdef NDEBUG
+ static const bool value = true;
+#else
+ static const bool value = false;
+#endif
+};
+
+
+/// TrackingVH - This is a value handle that tracks a Value (or Value subclass),
+/// even across RAUW operations.
+///
+/// TrackingVH is designed for situations where a client needs to hold a handle
+/// to a Value (or subclass) across some operations which may move that value,
+/// but should never destroy it or replace it with some unacceptable type.
+///
+/// It is an error to do anything with a TrackingVH whose value has been
+/// destroyed, except to destruct it.
+///
+/// It is an error to attempt to replace a value with one of a type which is
+/// incompatible with any of its outstanding TrackingVHs.
+template<typename ValueTy>
+class TrackingVH : public ValueHandleBase {
+ void CheckValidity() const {
+ Value *VP = ValueHandleBase::getValPtr();
+
+ // Null is always ok.
+ if (!VP) return;
+
+ // Check that this value is valid (i.e., it hasn't been deleted). We
+ // explicitly delay this check until access to avoid requiring clients to be
+ // unnecessarily careful w.r.t. destruction.
+ assert(ValueHandleBase::isValid(VP) && "Tracked Value was deleted!");
+
+ // Check that the value is a member of the correct subclass. We would like
+ // to check this property on assignment for better debugging, but we don't
+ // want to require a virtual interface on this VH. Instead we allow RAUW to
+ // replace this value with a value of an invalid type, and check it here.
+ assert(isa<ValueTy>(VP) &&
+ "Tracked Value was replaced by one with an invalid type!");
+ }
+
+ ValueTy *getValPtr() const {
+ CheckValidity();
+ return (ValueTy*)ValueHandleBase::getValPtr();
+ }
+ void setValPtr(ValueTy *P) {
+ CheckValidity();
+ ValueHandleBase::operator=(GetAsValue(P));
+ }
+
+ // Convert a ValueTy*, which may be const, to the type the base
+ // class expects.
+ static Value *GetAsValue(Value *V) { return V; }
+ static Value *GetAsValue(const Value *V) { return const_cast<Value*>(V); }
+
+public:
+ TrackingVH() : ValueHandleBase(Tracking) {}
+ TrackingVH(ValueTy *P) : ValueHandleBase(Tracking, GetAsValue(P)) {}
+ TrackingVH(const TrackingVH &RHS) : ValueHandleBase(Tracking, RHS) {}
+
+ operator ValueTy*() const {
+ return getValPtr();
+ }
+
+ ValueTy *operator=(ValueTy *RHS) {
+ setValPtr(RHS);
+ return getValPtr();
+ }
+ ValueTy *operator=(const TrackingVH<ValueTy> &RHS) {
+ setValPtr(RHS.getValPtr());
+ return getValPtr();
+ }
+
+ ValueTy *operator->() const { return getValPtr(); }
+ ValueTy &operator*() const { return *getValPtr(); }
+};
+
+// Specialize simplify_type to allow TrackingVH to participate in
+// dyn_cast, isa, etc.
+template<typename From> struct simplify_type;
+template<> struct simplify_type<const TrackingVH<Value> > {
+ typedef Value* SimpleType;
+ static SimpleType getSimplifiedValue(const TrackingVH<Value> &AVH) {
+ return static_cast<Value *>(AVH);
+ }
+};
+template<> struct simplify_type<TrackingVH<Value> >
+ : public simplify_type<const TrackingVH<Value> > {};
+
/// CallbackVH - This is a value handle that allows subclasses to define
/// callbacks that run when the underlying Value has RAUW called on it or is
/// destroyed. This class can be used as the key of a map, as long as the user
/// _before_ any of the uses have actually been replaced. If WeakVH were
/// implemented as a CallbackVH, it would use this method to call
/// setValPtr(new_value). AssertingVH would do nothing in this method.
- virtual void allUsesReplacedWith(Value *new_value) {}
+ virtual void allUsesReplacedWith(Value *) {}
+};
+
+// Specialize simplify_type to allow CallbackVH to participate in
+// dyn_cast, isa, etc.
+template<typename From> struct simplify_type;
+template<> struct simplify_type<const CallbackVH> {
+ typedef Value* SimpleType;
+ static SimpleType getSimplifiedValue(const CallbackVH &CVH) {
+ return static_cast<Value *>(CVH);
+ }
};
+template<> struct simplify_type<CallbackVH>
+ : public simplify_type<const CallbackVH> {};
} // End llvm namespace
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