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
|
//===-- llvm/Metadata.h - Constant class subclass definitions ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// @file
/// This file contains the declarations for the subclasses of Constant,
/// which represent the different flavors of constant values that live in LLVM.
/// Note that Constants are immutable (once created they never change) and are
/// fully shared by structural equivalence. This means that two structurally
/// equivalent constants will always have the same address. Constant's are
/// created on demand as needed and never deleted: thus clients don't have to
/// worry about the lifetime of the objects.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MDNODE_H
#define LLVM_MDNODE_H
#include "llvm/Constant.h"
#include "llvm/Type.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ValueHandle.h"
namespace llvm {
//===----------------------------------------------------------------------===//
/// MDNode - a tuple of other values.
/// These contain a list of the Constants that represent the metadata. The
/// operand list is always empty, query the element list instead.
///
/// This class will attempt to keep track of values as they are modified. When
/// a value is replaced the element will be replaced with it, and when the
/// value is deleted the element is set to a null pointer. In order to preserve
/// structural equivalence while the elements mutate, the MDNode may call
/// replaceAllUsesWith on itself. Because of this, users of MDNode must use a
/// WeakVH or CallbackVH to hold the node pointer if there is a chance that one
/// of the elements held by the node may change.
///
class MDNode : public Constant, public FoldingSetNode {
MDNode(const MDNode &); // DO NOT IMPLEMENT
friend class ElementVH;
struct ElementVH : public CallbackVH {
MDNode *OwningNode;
ElementVH(Value *V, MDNode *Parent)
: CallbackVH(V), OwningNode(Parent) {}
~ElementVH() {}
/// deleted - Set this entry in the MDNode to 'null'. This will reallocate
/// the MDNode.
virtual void deleted() {
OwningNode->replaceElement(this->operator Value*(), 0);
}
/// allUsesReplacedWith - Modify the MDNode by replacing this entry with
/// new_value. This will reallocate the MDNode.
virtual void allUsesReplacedWith(Value *new_value) {
OwningNode->replaceElement(this->operator Value*(), new_value);
}
};
void replaceElement(Value *From, Value *To);
SmallVector<ElementVH, 4> Node;
typedef SmallVectorImpl<ElementVH>::iterator elem_iterator;
protected:
explicit MDNode(Value*const* Vals, unsigned NumVals);
public:
typedef SmallVectorImpl<ElementVH>::const_iterator const_elem_iterator;
/// get() - Static factory methods - Return objects of the specified value.
///
static MDNode *get(Value*const* Vals, unsigned NumVals);
Value *getElement(unsigned i) const {
return Node[i];
}
unsigned getNumElements() const {
return Node.size();
}
bool elem_empty() const {
return Node.empty();
}
const_elem_iterator elem_begin() const {
return Node.begin();
}
const_elem_iterator elem_end() const {
return Node.end();
}
/// getType() specialization - Type is always MetadataTy.
///
inline const Type *getType() const {
return Type::MetadataTy;
}
/// isNullValue - Return true if this is the value that would be returned by
/// getNullValue. This always returns false because getNullValue will never
/// produce metadata.
virtual bool isNullValue() const {
return false;
}
/// Profile - calculate a unique identifier for this MDNode to collapse
/// duplicates
void Profile(FoldingSetNodeID &ID) const;
virtual void destroyConstant();
virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
LLVM_UNREACHABLE("This should never be called because MDNodes have no ops");
}
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const MDNode *) { return true; }
static bool classof(const Value *V) {
return V->getValueID() == MDNodeVal;
}
};
} // end llvm namespace
#endif
|
