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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
|
//===-- Use.cpp - Implement the Use class ---------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the algorithm for finding the User of a Use.
//
//===----------------------------------------------------------------------===//
#include "llvm/User.h"
namespace llvm {
//===----------------------------------------------------------------------===//
// Use swap Implementation
//===----------------------------------------------------------------------===//
void Use::swap(Use &RHS) {
Value *V1(Val);
Value *V2(RHS.Val);
if (V1 != V2) {
if (V1) {
removeFromList();
}
if (V2) {
RHS.removeFromList();
Val = V2;
V2->addUse(*this);
} else {
Val = 0;
}
if (V1) {
RHS.Val = V1;
V1->addUse(RHS);
} else {
RHS.Val = 0;
}
}
}
//===----------------------------------------------------------------------===//
// Use getImpliedUser Implementation
//===----------------------------------------------------------------------===//
const Use *Use::getImpliedUser() const {
const Use *Current = this;
while (true) {
unsigned Tag = (Current++)->Prev.getInt();
switch (Tag) {
case zeroDigitTag:
case oneDigitTag:
continue;
case stopTag: {
++Current;
ptrdiff_t Offset = 1;
while (true) {
unsigned Tag = Current->Prev.getInt();
switch (Tag) {
case zeroDigitTag:
case oneDigitTag:
++Current;
Offset = (Offset << 1) + Tag;
continue;
default:
return Current + Offset;
}
}
}
case fullStopTag:
return Current;
}
}
}
//===----------------------------------------------------------------------===//
// Use initTags Implementation
//===----------------------------------------------------------------------===//
Use *Use::initTags(Use * const Start, Use *Stop, ptrdiff_t Done) {
ptrdiff_t Count = Done;
while (Start != Stop) {
--Stop;
Stop->Val = 0;
if (!Count) {
Stop->Prev.setFromOpaqueValue(reinterpret_cast<Use**>(Done == 0
? fullStopTag
: stopTag));
++Done;
Count = Done;
} else {
Stop->Prev.setFromOpaqueValue(reinterpret_cast<Use**>(Count & 1));
Count >>= 1;
++Done;
}
}
return Start;
}
//===----------------------------------------------------------------------===//
// Use zap Implementation
//===----------------------------------------------------------------------===//
void Use::zap(Use *Start, const Use *Stop, bool del) {
if (del) {
while (Start != Stop) {
(--Stop)->~Use();
}
::operator delete(Start);
return;
}
while (Start != Stop) {
(Start++)->set(0);
}
}
//===----------------------------------------------------------------------===//
// AugmentedUse layout struct
//===----------------------------------------------------------------------===//
struct AugmentedUse : public Use {
PointerIntPair<User*, 1, Tag> ref;
AugmentedUse(); // not implemented
};
//===----------------------------------------------------------------------===//
// Use getUser Implementation
//===----------------------------------------------------------------------===//
User *Use::getUser() const {
const Use *End = getImpliedUser();
const PointerIntPair<User*, 1, Tag>& ref(
static_cast<const AugmentedUse*>(End - 1)->ref);
User *She = ref.getPointer();
return ref.getInt()
? She
: (User*)End;
}
//===----------------------------------------------------------------------===//
// User allocHungoffUses Implementation
//===----------------------------------------------------------------------===//
Use *User::allocHungoffUses(unsigned N) const {
Use *Begin = static_cast<Use*>(::operator new(sizeof(Use) * N
+ sizeof(AugmentedUse)
- sizeof(Use)));
Use *End = Begin + N;
PointerIntPair<User*, 1, Tag>& ref(static_cast<AugmentedUse&>(End[-1]).ref);
ref.setPointer(const_cast<User*>(this));
ref.setInt(tagOne);
return Use::initTags(Begin, End);
}
//===----------------------------------------------------------------------===//
// User operator new Implementations
//===----------------------------------------------------------------------===//
void *User::operator new(size_t s, unsigned Us) {
void *Storage = ::operator new(s + sizeof(Use) * Us);
Use *Start = static_cast<Use*>(Storage);
Use *End = Start + Us;
User *Obj = reinterpret_cast<User*>(End);
Obj->OperandList = Start;
Obj->NumOperands = Us;
Use::initTags(Start, End);
return Obj;
}
/// Prefixed allocation - just before the first Use, allocate a NULL pointer.
/// The destructor can detect its presence and readjust the OperandList
/// for deletition.
///
void *User::operator new(size_t s, unsigned Us, bool Prefix) {
// currently prefixed allocation only admissible for
// unconditional branch instructions
if (!Prefix)
return operator new(s, Us);
assert(Us == 1 && "Other than one Use allocated?");
typedef PointerIntPair<void*, 2, Use::PrevPtrTag> TaggedPrefix;
void *Raw = ::operator new(s + sizeof(TaggedPrefix) + sizeof(Use) * Us);
TaggedPrefix *Pre = static_cast<TaggedPrefix*>(Raw);
Pre->setFromOpaqueValue(0);
void *Storage = Pre + 1; // skip over prefix
Use *Start = static_cast<Use*>(Storage);
Use *End = Start + Us;
User *Obj = reinterpret_cast<User*>(End);
Obj->OperandList = Start;
Obj->NumOperands = Us;
Use::initTags(Start, End);
return Obj;
}
//===----------------------------------------------------------------------===//
// User operator delete Implementation
//===----------------------------------------------------------------------===//
void User::operator delete(void *Usr) {
User *Start = static_cast<User*>(Usr);
Use *Storage = static_cast<Use*>(Usr) - Start->NumOperands;
//
// look for a variadic User
if (Storage == Start->OperandList) {
::operator delete(Storage);
return;
}
//
// check for the flag whether the destructor has detected a prefixed
// allocation, in which case we remove the flag and delete starting
// at OperandList
if (reinterpret_cast<intptr_t>(Start->OperandList) & 1) {
::operator delete(reinterpret_cast<char*>(Start->OperandList) - 1);
return;
}
//
// in all other cases just delete the nullary User (covers hung-off
// uses also
::operator delete(Usr);
}
} // End llvm namespace
|
