summaryrefslogtreecommitdiffstats
path: root/include/llvm/IR/TrackingMDRef.h
blob: e24112154e1608f60f7649af4fc43a1287b36bff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
//===- llvm/IR/TrackingMDRef.h - Tracking Metadata references ---*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// References to metadata that track RAUW.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_TRACKINGMDREF_H
#define LLVM_IR_TRACKINGMDREF_H

#include "llvm/IR/MetadataTracking.h"
#include "llvm/Support/Casting.h"

namespace llvm {

class Metadata;
class MDNode;
class ValueAsMetadata;

/// \brief Tracking metadata reference.
///
/// This class behaves like \a TrackingVH, but for metadata.
class TrackingMDRef {
  Metadata *MD;

public:
  TrackingMDRef() : MD(nullptr) {}
  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();
  }

  /// \brief 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;
    }
  }
};

/// \brief 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() {}
  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)); }

  /// \brief Check whether this has a trivial destructor.
  bool hasTrivialDestructor() const { return Ref.hasTrivialDestructor(); }
};

typedef TypedTrackingMDRef<MDNode> TrackingMDNodeRef;
typedef TypedTrackingMDRef<ValueAsMetadata> TrackingValueAsMetadataRef;

// Expose the underlying metadata to casting.
template <> struct simplify_type<TrackingMDRef> {
  typedef Metadata *SimpleType;
  static SimpleType getSimplifiedValue(TrackingMDRef &MD) { return MD.get(); }
};

template <> struct simplify_type<const TrackingMDRef> {
  typedef Metadata *SimpleType;
  static SimpleType getSimplifiedValue(const TrackingMDRef &MD) {
    return MD.get();
  }
};

template <class T> struct simplify_type<TypedTrackingMDRef<T>> {
  typedef T *SimpleType;
  static SimpleType getSimplifiedValue(TypedTrackingMDRef<T> &MD) {
    return MD.get();
  }
};

template <class T> struct simplify_type<const TypedTrackingMDRef<T>> {
  typedef T *SimpleType;
  static SimpleType getSimplifiedValue(const TypedTrackingMDRef<T> &MD) {
    return MD.get();
  }
};

} // end namespace llvm

#endif