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thirdparty/capstone/suite/synctools/tablegen/include/llvm/IR/TrackingMDRef.h

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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 references 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