blob: f8180f3ef8cec6c10c37e8714705008d93293756 (
plain) (
blame)
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
|
#pragma once
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#endif
//===- llvm/Use.h - Definition of the Use class -----------------*- 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
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This defines the Use class. The Use class represents the operand of an
/// instruction or some other User instance which refers to a Value. The Use
/// class keeps the "use list" of the referenced value up to date.
///
/// Pointer tagging is used to efficiently find the User corresponding to a Use
/// without having to store a User pointer in every Use. A User is preceded in
/// memory by all the Uses corresponding to its operands, and the low bits of
/// one of the fields (Prev) of the Use class are used to encode offsets to be
/// able to find that User given a pointer to any Use. For details, see:
///
/// http://www.llvm.org/docs/ProgrammersManual.html#UserLayout
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_USE_H
#define LLVM_IR_USE_H
#include "llvm-c/Types.h"
#include "llvm/Support/CBindingWrapping.h"
#include "llvm/Support/Compiler.h"
namespace llvm {
template <typename> struct simplify_type;
class User;
class Value;
/// A Use represents the edge between a Value definition and its users.
///
/// This is notionally a two-dimensional linked list. It supports traversing
/// all of the uses for a particular value definition. It also supports jumping
/// directly to the used value when we arrive from the User's operands, and
/// jumping directly to the User when we arrive from the Value's uses.
class Use {
public:
Use(const Use &U) = delete;
/// Provide a fast substitute to std::swap<Use>
/// that also works with less standard-compliant compilers
void swap(Use &RHS);
private:
/// Destructor - Only for zap()
~Use() {
if (Val)
removeFromList();
}
/// Constructor
Use(User *Parent) : Parent(Parent) {}
public:
friend class Value;
friend class User;
operator Value *() const { return Val; }
Value *get() const { return Val; }
/// Returns the User that contains this Use.
///
/// For an instruction operand, for example, this will return the
/// instruction.
User *getUser() const { return Parent; };
inline void set(Value *Val);
inline Value *operator=(Value *RHS);
inline const Use &operator=(const Use &RHS);
Value *operator->() { return Val; }
const Value *operator->() const { return Val; }
Use *getNext() const { return Next; }
/// Return the operand # of this use in its User.
unsigned getOperandNo() const;
/// Destroys Use operands when the number of operands of
/// a User changes.
static void zap(Use *Start, const Use *Stop, bool del = false);
private:
Value *Val = nullptr;
Use *Next = nullptr;
Use **Prev = nullptr;
User *Parent = nullptr;
void addToList(Use **List) {
Next = *List;
if (Next)
Next->Prev = &Next;
Prev = List;
*Prev = this;
}
void removeFromList() {
*Prev = Next;
if (Next)
Next->Prev = Prev;
}
};
/// Allow clients to treat uses just like values when using
/// casting operators.
template <> struct simplify_type<Use> {
using SimpleType = Value *;
static SimpleType getSimplifiedValue(Use &Val) { return Val.get(); }
};
template <> struct simplify_type<const Use> {
using SimpleType = /*const*/ Value *;
static SimpleType getSimplifiedValue(const Use &Val) { return Val.get(); }
};
// Create wrappers for C Binding types (see CBindingWrapping.h).
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(Use, LLVMUseRef)
} // end namespace llvm
#endif // LLVM_IR_USE_H
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
|
