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
234
|
// SPDX-License-Identifier: GPL-3.0-or-later
#include "rcc/CodeGen/MachineFrameInfo.h"
#include <cstddef>
#include <cstdint>
#include <limits>
#include <unordered_set>
#include <utility>
namespace rcc {
Expected<StackID> StackID::targetStack(std::uint32_t Value) {
if (Value < FirstTargetStackValue) {
return makeUnexpected(ErrorCode::InvalidArgument,
"target stack ID must not overlap a built-in stack ID");
}
return StackID(Value);
}
bool StackObject::isSpill() const noexcept {
const StackObjectDesc *Desc = description();
if (Desc == nullptr)
return false;
return Desc->Kind == StackObjectKind::SpillSlot || Desc->Kind == StackObjectKind::CalleeSaved ||
Desc->Kind == StackObjectKind::EmergencySpill;
}
bool StackObject::isFixed() const noexcept {
const StackObjectDesc *Desc = description();
return Desc != nullptr && Desc->Kind == StackObjectKind::FixedABI;
}
bool StackObject::isVariableSized() const noexcept {
const StackObjectDesc *Desc = description();
return Desc != nullptr && (Desc->Kind == StackObjectKind::VariableSized ||
Desc->Kind == StackObjectKind::DynamicAlloca);
}
Expected<void> MachineFrameInfo::verifyDescription(const StackObjectDesc &Description) {
if (Description.Kind >= StackObjectKind::Count)
return makeUnexpected(ErrorCode::InvalidArgument, "stack object kind is invalid");
if (!Description.Stack.isValid())
return makeUnexpected(ErrorCode::InvalidArgument, "stack object has an invalid stack ID");
const bool IsVariable = Description.Kind == StackObjectKind::VariableSized ||
Description.Kind == StackObjectKind::DynamicAlloca;
if (IsVariable) {
if (Description.Size || Description.Offset) {
return makeUnexpected(ErrorCode::InvalidArgument,
"variable-sized stack objects cannot have a fixed size or offset");
}
} else if (!Description.Size || *Description.Size == 0) {
return makeUnexpected(ErrorCode::InvalidArgument,
"fixed-size stack objects require a nonzero size");
}
if (Description.Kind == StackObjectKind::FixedABI && !Description.Offset) {
return makeUnexpected(ErrorCode::InvalidArgument,
"fixed ABI stack objects require a fixed offset");
}
if (Description.Kind == StackObjectKind::Target && !Description.Stack.isTargetStack() &&
Description.TargetFlags == 0) {
return makeUnexpected(ErrorCode::InvalidArgument,
"target stack objects require a target stack ID or nonzero target flags");
}
std::unordered_set<MachineInstrStableID> LifetimeBoundaries;
for (const StackObjectLifetimeRange &Range : Description.Lifetime) {
if (!Range.Begin.isValid() || !Range.End.isValid() || Range.Begin == Range.End) {
return makeUnexpected(ErrorCode::InvalidArgument,
"stack object lifetime boundaries must be valid and distinct");
}
if (!LifetimeBoundaries.insert(Range.Begin).second ||
!LifetimeBoundaries.insert(Range.End).second) {
return makeUnexpected(ErrorCode::InvalidArgument,
"stack object lifetime boundaries must not be reused");
}
}
return {};
}
Expected<FrameIndex> MachineFrameInfo::createObject(StackObjectDesc Description) {
if (Frozen)
return makeUnexpected(ErrorCode::InvalidArgument, "frozen frame cannot create stack objects");
auto DescriptionResult = verifyDescription(Description);
if (!DescriptionResult)
return std::unexpected(DescriptionResult.error());
if (Objects.size() > std::numeric_limits<std::uint32_t>::max()) {
return makeUnexpected(ErrorCode::Unsupported, "stack object index space is exhausted");
}
const FrameIndex Index = FrameIndex::fromValue(static_cast<std::uint32_t>(Objects.size()));
Objects.push_back(StackObject(Index, std::move(Description)));
return Index;
}
Expected<StackObject *> MachineFrameInfo::mutableObject(FrameIndex Index) {
if (Frozen)
return makeUnexpected(ErrorCode::InvalidArgument, "frozen frame cannot modify stack objects");
if (Index.value() >= Objects.size())
return makeUnexpected(ErrorCode::InvalidArgument, "stack object index is out of range");
StackObject &Object = Objects[Index.value()];
if (Object.isTombstone())
return makeUnexpected(ErrorCode::InvalidArgument, "stack object index is a tombstone");
return &Object;
}
Expected<void> MachineFrameInfo::updateObject(FrameIndex Index, StackObjectDesc Description) {
auto DescriptionResult = verifyDescription(Description);
if (!DescriptionResult)
return std::unexpected(DescriptionResult.error());
auto Object = mutableObject(Index);
if (!Object)
return std::unexpected(Object.error());
(*Object)->Description.emplace<StackObjectDesc>(std::move(Description));
return {};
}
Expected<void> MachineFrameInfo::setObjectOffset(FrameIndex Index, std::int64_t Offset) {
auto Object = mutableObject(Index);
if (!Object)
return std::unexpected(Object.error());
StackObjectDesc *CurrentDescription = std::get_if<StackObjectDesc>(&(*Object)->Description);
if (CurrentDescription == nullptr) {
return makeUnexpected(ErrorCode::InternalError,
"live stack object unexpectedly lacks a description");
}
StackObjectDesc Description = *CurrentDescription;
if ((*Object)->isVariableSized()) {
return makeUnexpected(ErrorCode::InvalidArgument,
"variable-sized stack object cannot have a fixed offset");
}
Description.Offset = Offset;
(*Object)->Description.emplace<StackObjectDesc>(std::move(Description));
return {};
}
Expected<void> MachineFrameInfo::markObjectDead(FrameIndex Index) {
auto Object = mutableObject(Index);
if (!Object)
return std::unexpected(Object.error());
StackObjectDesc *Description = std::get_if<StackObjectDesc>(&(*Object)->Description);
if (Description == nullptr) {
return makeUnexpected(ErrorCode::InternalError,
"live stack object unexpectedly lacks a description");
}
Description->IsDead = true;
return {};
}
Expected<void> MachineFrameInfo::eraseObject(FrameIndex Index) {
auto Object = mutableObject(Index);
if (!Object)
return std::unexpected(Object.error());
(*Object)->Description.emplace<std::monostate>();
return {};
}
const StackObject *MachineFrameInfo::object(FrameIndex Index) const noexcept {
if (Index.value() >= Objects.size() || Objects[Index.value()].isTombstone())
return nullptr;
return &Objects[Index.value()];
}
std::size_t MachineFrameInfo::liveObjectCount() const noexcept {
std::size_t Count = 0;
for (const StackObject &Object : Objects) {
if (!Object.isTombstone())
++Count;
}
return Count;
}
Expected<void> MachineFrameInfo::setMaxCallFrameSize(std::uint64_t Size) {
if (Frozen)
return makeUnexpected(ErrorCode::InvalidArgument,
"frozen frame cannot change its maximum call-frame size");
MaxCallFrameSize = Size;
return {};
}
Expected<void> MachineFrameInfo::freeze(std::uint64_t Size, Alignment Align) {
if (Frozen)
return makeUnexpected(ErrorCode::InvalidArgument, "frame layout is already frozen");
for (const StackObject &Object : Objects) {
if (Object.isTombstone() || Object.isVariableSized())
continue;
if (!Object.description()->Offset) {
return makeUnexpected(ErrorCode::VerificationError,
"fixed-size stack object is missing its final offset");
}
}
if (Size % Align.bytes() != 0) {
return makeUnexpected(ErrorCode::InvalidArgument,
"static stack size must be aligned to the stack alignment");
}
StaticStackSize = Size;
StackAlign = Align;
Frozen = true;
return {};
}
Expected<void> MachineFrameInfo::verify() const {
for (std::size_t Position = 0; Position < Objects.size(); ++Position) {
const StackObject &Object = Objects[Position];
if (Object.index() != FrameIndex::fromValue(static_cast<std::uint32_t>(Position))) {
return makeUnexpected(ErrorCode::VerificationError,
"stack object index does not match its stable table position");
}
if (Object.isTombstone())
continue;
auto DescriptionResult = verifyDescription(*Object.description());
if (!DescriptionResult)
return std::unexpected(DescriptionResult.error());
if (Frozen && !Object.isVariableSized() && !Object.description()->Offset) {
return makeUnexpected(ErrorCode::VerificationError,
"frozen fixed-size stack object has no final offset");
}
}
if (Frozen != StaticStackSize.has_value()) {
return makeUnexpected(ErrorCode::VerificationError,
"frame frozen state and static stack size are inconsistent");
}
if (Frozen && *StaticStackSize % StackAlign.bytes() != 0) {
return makeUnexpected(ErrorCode::VerificationError,
"frozen static stack size violates stack alignment");
}
return {};
}
} // namespace rcc
|
