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//===- llvm/IR/TrackingMDRef.h - Tracking Metadata references ---*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// References to metadata that track RAUW.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_TRACKINGMDREF_H
#define LLVM_IR_TRACKINGMDREF_H
#include "llvm/IR/Metadata.h"
#include <algorithm>
#include <cassert>
namespace llvm {
/// Tracking metadata reference.
///
/// This class behaves like \a TrackingVH, but for metadata.
class TrackingMDRef {
Metadata *MD = nullptr;
public:
TrackingMDRef() = default;
explicit TrackingMDRef(Metadata *MD) : MD(MD) { track(); }
TrackingMDRef(TrackingMDRef &&X) : MD(X.MD) { retrack(X); }
TrackingMDRef(const TrackingMDRef &X) : MD(X.MD) { track(); }
TrackingMDRef &operator=(TrackingMDRef &&X) {
if (&X == this)
return *this;
untrack();
MD = X.MD;
retrack(X);
return *this;
}
TrackingMDRef &operator=(const TrackingMDRef &X) {
if (&X == this)
return *this;
untrack();
MD = X.MD;
track();
return *this;
}
~TrackingMDRef() { untrack(); }
Metadata *get() const { return MD; }
operator Metadata *() const { return get(); }
Metadata *operator->() const { return get(); }
Metadata &operator*() const { return *get(); }
void reset() {
untrack();
MD = nullptr;
}
void reset(Metadata *MD) {
untrack();
this->MD = MD;
track();
}
/// Check whether this has a trivial destructor.
///
/// If \c MD isn't replaceable, the destructor will be a no-op.
bool hasTrivialDestructor() const {
return !MD || !MetadataTracking::isReplaceable(*MD);
}
bool operator==(const TrackingMDRef &X) const { return MD == X.MD; }
bool operator!=(const TrackingMDRef &X) const { return MD != X.MD; }
private:
void track() {
if (MD)
MetadataTracking::track(MD);
}
void untrack() {
if (MD)
MetadataTracking::untrack(MD);
}
void retrack(TrackingMDRef &X) {
assert(MD == X.MD && "Expected values to match");
if (X.MD) {
MetadataTracking::retrack(X.MD, MD);
X.MD = nullptr;
}
}
};
/// Typed tracking ref.
///
/// Track refererences of a particular type. It's useful to use this for \a
/// MDNode and \a ValueAsMetadata.
template <class T> class TypedTrackingMDRef {
TrackingMDRef Ref;
public:
TypedTrackingMDRef() = default;
explicit TypedTrackingMDRef(T *MD) : Ref(static_cast<Metadata *>(MD)) {}
TypedTrackingMDRef(TypedTrackingMDRef &&X) : Ref(std::move(X.Ref)) {}
TypedTrackingMDRef(const TypedTrackingMDRef &X) : Ref(X.Ref) {}
TypedTrackingMDRef &operator=(TypedTrackingMDRef &&X) {
Ref = std::move(X.Ref);
return *this;
}
TypedTrackingMDRef &operator=(const TypedTrackingMDRef &X) {
Ref = X.Ref;
return *this;
}
T *get() const { return (T *)Ref.get(); }
operator T *() const { return get(); }
T *operator->() const { return get(); }
T &operator*() const { return *get(); }
bool operator==(const TypedTrackingMDRef &X) const { return Ref == X.Ref; }
bool operator!=(const TypedTrackingMDRef &X) const { return Ref != X.Ref; }
void reset() { Ref.reset(); }
void reset(T *MD) { Ref.reset(static_cast<Metadata *>(MD)); }
/// Check whether this has a trivial destructor.
bool hasTrivialDestructor() const { return Ref.hasTrivialDestructor(); }
};
using TrackingMDNodeRef = TypedTrackingMDRef<MDNode>;
using TrackingValueAsMetadataRef = TypedTrackingMDRef<ValueAsMetadata>;
// Expose the underlying metadata to casting.
template <> struct simplify_type<TrackingMDRef> {
using SimpleType = Metadata *;
static SimpleType getSimplifiedValue(TrackingMDRef &MD) { return MD.get(); }
};
template <> struct simplify_type<const TrackingMDRef> {
using SimpleType = Metadata *;
static SimpleType getSimplifiedValue(const TrackingMDRef &MD) {
return MD.get();
}
};
template <class T> struct simplify_type<TypedTrackingMDRef<T>> {
using SimpleType = T *;
static SimpleType getSimplifiedValue(TypedTrackingMDRef<T> &MD) {
return MD.get();
}
};
template <class T> struct simplify_type<const TypedTrackingMDRef<T>> {
using SimpleType = T *;
static SimpleType getSimplifiedValue(const TypedTrackingMDRef<T> &MD) {
return MD.get();
}
};
} // end namespace llvm
#endif // LLVM_IR_TRACKINGMDREF_H
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