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
|
//===--- BitstreamVisitor.h - Helper for reading a bitstream --------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIB_INDEX_BITSTREAMVISITOR_H
#define LLVM_CLANG_LIB_INDEX_BITSTREAMVISITOR_H
#include "llvm/Bitstream/BitstreamReader.h"
#include "clang/Basic/LLVM.h"
#include "clang/Serialization/ASTReader.h"
#include <string>
namespace clang {
namespace index {
namespace store {
/// Helper class that saves the current stream position and
/// then restores it when destroyed.
struct SavedStreamPosition {
explicit SavedStreamPosition(llvm::BitstreamCursor &Cursor)
: Cursor(Cursor), Offset(Cursor.GetCurrentBitNo()) { }
~SavedStreamPosition() {
if (llvm::Error Err = Cursor.JumpToBit(Offset))
llvm::report_fatal_error(Twine("SavedStreamPosition failed jumping: ") +
toString(std::move(Err)));
}
private:
llvm::BitstreamCursor &Cursor;
uint64_t Offset;
};
enum class StreamVisit {
Continue,
Skip,
Abort
};
template <typename ImplClass>
class BitstreamVisitor {
SmallVector<unsigned, 4> BlockStack;
protected:
llvm::BitstreamCursor &Stream;
std::optional<llvm::BitstreamBlockInfo> BlockInfo;
std::string *Error;
public:
BitstreamVisitor(llvm::BitstreamCursor &Stream)
: Stream(Stream) {}
StreamVisit visitBlock(unsigned ID) {
return StreamVisit::Continue;
}
bool visit(std::string &Error) {
this->Error = &Error;
ASTReader::RecordData Record;
while (1) {
Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance(llvm::BitstreamCursor::AF_DontPopBlockAtEnd);
if (!MaybeEntry) {
Error = toString(MaybeEntry.takeError());
return false;
}
llvm::BitstreamEntry Entry = MaybeEntry.get();
switch (Entry.Kind) {
case llvm::BitstreamEntry::Error:
Error = "malformed serialization";
return false;
case llvm::BitstreamEntry::EndBlock:
if (BlockStack.empty())
return true;
BlockStack.pop_back();
if (Stream.ReadBlockEnd()) {
Error = "malformed serialization";
return false;
}
if (Stream.AtEndOfStream())
return true;
break;
case llvm::BitstreamEntry::SubBlock: {
if (Entry.ID == llvm::bitc::BLOCKINFO_BLOCK_ID) {
Expected<std::optional<llvm::BitstreamBlockInfo>> MaybeBlockInfo = Stream.ReadBlockInfoBlock();
if (!MaybeBlockInfo) {
Error = toString(MaybeBlockInfo.takeError());
return false;
}
BlockInfo = MaybeBlockInfo.get();
if (!BlockInfo) {
Error = "malformed BlockInfoBlock";
return false;
}
Stream.setBlockInfo(&*BlockInfo);
break;
}
StreamVisit Ret = static_cast<ImplClass*>(this)->visitBlock(Entry.ID);
switch (Ret) {
case StreamVisit::Continue:
if (Stream.EnterSubBlock(Entry.ID)) {
Error = "malformed block record";
return false;
}
if (llvm::Error Err = readBlockAbbrevs(Stream)) {
Error = toString(std::move(Err));
return false;
}
BlockStack.push_back(Entry.ID);
break;
case StreamVisit::Skip:
if (Stream.SkipBlock()) {
Error = "malformed serialization";
return false;
}
if (Stream.AtEndOfStream())
return true;
break;
case StreamVisit::Abort:
return false;
}
break;
}
case llvm::BitstreamEntry::Record: {
Record.clear();
StringRef Blob;
Expected<unsigned> MaybeRecID = Stream.readRecord(Entry.ID, Record, &Blob);
if (!MaybeRecID) {
Error = toString(MaybeRecID.takeError());
return false;
}
unsigned RecID = MaybeRecID.get();
unsigned BlockID = BlockStack.empty() ? 0 : BlockStack.back();
StreamVisit Ret = static_cast<ImplClass*>(this)->visitRecord(BlockID, RecID, Record, Blob);
switch (Ret) {
case StreamVisit::Continue:
break;
case StreamVisit::Skip:
if (Expected<unsigned> Skipped = Stream.skipRecord(Entry.ID)) {
Error = toString(Skipped.takeError());
return false;
}
break;
case StreamVisit::Abort:
return false;
}
break;
}
}
}
}
static llvm::Error readBlockAbbrevs(llvm::BitstreamCursor &Cursor) {
while (true) {
uint64_t Offset = Cursor.GetCurrentBitNo();
Expected<unsigned> MaybeCode = Cursor.ReadCode();
if (!MaybeCode)
return MaybeCode.takeError();
unsigned Code = MaybeCode.get();
// We expect all abbrevs to be at the start of the block.
if (Code != llvm::bitc::DEFINE_ABBREV) {
if (llvm::Error Err = Cursor.JumpToBit(Offset))
return Err;
return llvm::Error::success();
}
if (llvm::Error Err = Cursor.ReadAbbrevRecord())
return Err;
}
}
};
} // end namespace store
} // end namespace index
} // end namespace clang
#endif
|
