Bug Summary

File:include/llvm/Bitcode/BitstreamReader.h
Warning:line 208, column 39
The result of the right shift is undefined due to shifting by '64', which is greater or equal to the width of type 'llvm::SimpleBitstreamCursor::word_t'

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SerializedDiagnosticReader.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -relaxed-aliasing -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-9/lib/clang/9.0.0 -D CLANG_VENDOR="Debian " -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/tools/clang/lib/Frontend -I /build/llvm-toolchain-snapshot-9~svn362543/tools/clang/lib/Frontend -I /build/llvm-toolchain-snapshot-9~svn362543/tools/clang/include -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/include -I /build/llvm-toolchain-snapshot-9~svn362543/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/9.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-9/lib/clang/9.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/tools/clang/lib/Frontend -fdebug-prefix-map=/build/llvm-toolchain-snapshot-9~svn362543=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fno-common -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2019-06-05-060531-1271-1 -x c++ /build/llvm-toolchain-snapshot-9~svn362543/tools/clang/lib/Frontend/SerializedDiagnosticReader.cpp -faddrsig

/build/llvm-toolchain-snapshot-9~svn362543/tools/clang/lib/Frontend/SerializedDiagnosticReader.cpp

→
1//===- SerializedDiagnosticReader.cpp - Reads diagnostics -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "clang/Frontend/SerializedDiagnosticReader.h"
10#include "clang/Basic/FileManager.h"
11#include "clang/Basic/FileSystemOptions.h"
12#include "clang/Frontend/SerializedDiagnostics.h"
13#include "llvm/ADT/Optional.h"
14#include "llvm/ADT/SmallVector.h"
15#include "llvm/ADT/StringRef.h"
16#include "llvm/Bitcode/BitCodes.h"
17#include "llvm/Bitcode/BitstreamReader.h"
18#include "llvm/Support/Compiler.h"
19#include "llvm/Support/ErrorHandling.h"
20#include "llvm/Support/ErrorOr.h"
21#include "llvm/Support/ManagedStatic.h"
22#include <cstdint>
23#include <system_error>
24
25using namespace clang;
26using namespace serialized_diags;
27
28std::error_code SerializedDiagnosticReader::readDiagnostics(StringRef File) {
29 // Open the diagnostics file.
30 FileSystemOptions FO;
31 FileManager FileMgr(FO);
32
33 auto Buffer = FileMgr.getBufferForFile(File);
34 if (!Buffer)
35 return SDError::CouldNotLoad;
36
37 llvm::BitstreamCursor Stream(**Buffer);
38 Optional<llvm::BitstreamBlockInfo> BlockInfo;
39
40 if (Stream.AtEndOfStream())
41 return SDError::InvalidSignature;
42
43 // Sniff for the signature.
44 if (Stream.Read(8) != 'D' ||
45 Stream.Read(8) != 'I' ||
46 Stream.Read(8) != 'A' ||
47 Stream.Read(8) != 'G')
48 return SDError::InvalidSignature;
49
50 // Read the top level blocks.
51 while (!Stream.AtEndOfStream()) {
52 if (Stream.ReadCode() != llvm::bitc::ENTER_SUBBLOCK)
53 return SDError::InvalidDiagnostics;
54
55 std::error_code EC;
56 switch (Stream.ReadSubBlockID()) {
57 case llvm::bitc::BLOCKINFO_BLOCK_ID:
58 BlockInfo = Stream.ReadBlockInfoBlock();
59 if (!BlockInfo)
60 return SDError::MalformedBlockInfoBlock;
61 Stream.setBlockInfo(&*BlockInfo);
62 continue;
63 case BLOCK_META:
64 if ((EC = readMetaBlock(Stream)))
65 return EC;
66 continue;
67 case BLOCK_DIAG:
68 if ((EC = readDiagnosticBlock(Stream)))
69 return EC;
70 continue;
71 default:
72 if (!Stream.SkipBlock())
73 return SDError::MalformedTopLevelBlock;
74 continue;
75 }
76 }
77 return {};
78}
79
80enum class SerializedDiagnosticReader::Cursor {
81 Record = 1,
82 BlockEnd,
83 BlockBegin
84};
85
86llvm::ErrorOr<SerializedDiagnosticReader::Cursor>
87SerializedDiagnosticReader::skipUntilRecordOrBlock(
88 llvm::BitstreamCursor &Stream, unsigned &BlockOrRecordID) {
89 BlockOrRecordID = 0;
90
91 while (!Stream.AtEndOfStream()) {
6
←
Loop condition is true. Entering loop body
→
92 unsigned Code = Stream.ReadCode();
7
←
Calling 'BitstreamCursor::ReadCode'
→
93
94 switch ((llvm::bitc::FixedAbbrevIDs)Code) {
95 case llvm::bitc::ENTER_SUBBLOCK:
96 BlockOrRecordID = Stream.ReadSubBlockID();
97 return Cursor::BlockBegin;
98
99 case llvm::bitc::END_BLOCK:
100 if (Stream.ReadBlockEnd())
101 return SDError::InvalidDiagnostics;
102 return Cursor::BlockEnd;
103
104 case llvm::bitc::DEFINE_ABBREV:
105 Stream.ReadAbbrevRecord();
106 continue;
107
108 case llvm::bitc::UNABBREV_RECORD:
109 return SDError::UnsupportedConstruct;
110
111 default:
112 // We found a record.
113 BlockOrRecordID = Code;
114 return Cursor::Record;
115 }
116 }
117
118 return SDError::InvalidDiagnostics;
119}
120
121std::error_code
122SerializedDiagnosticReader::readMetaBlock(llvm::BitstreamCursor &Stream) {
123 if (Stream.EnterSubBlock(clang::serialized_diags::BLOCK_META))
124 return SDError::MalformedMetadataBlock;
125
126 bool VersionChecked = false;
127
128 while (true) {
129 unsigned BlockOrCode = 0;
130 llvm::ErrorOr<Cursor> Res = skipUntilRecordOrBlock(Stream, BlockOrCode);
131 if (!Res)
132 Res.getError();
133
134 switch (Res.get()) {
135 case Cursor::Record:
136 break;
137 case Cursor::BlockBegin:
138 if (Stream.SkipBlock())
139 return SDError::MalformedMetadataBlock;
140 LLVM_FALLTHROUGH[[clang::fallthrough]];
141 case Cursor::BlockEnd:
142 if (!VersionChecked)
143 return SDError::MissingVersion;
144 return {};
145 }
146
147 SmallVector<uint64_t, 1> Record;
148 unsigned RecordID = Stream.readRecord(BlockOrCode, Record);
149
150 if (RecordID == RECORD_VERSION) {
151 if (Record.size() < 1)
152 return SDError::MissingVersion;
153 if (Record[0] > VersionNumber)
154 return SDError::VersionMismatch;
155 VersionChecked = true;
156 }
157 }
158}
159
160std::error_code
161SerializedDiagnosticReader::readDiagnosticBlock(llvm::BitstreamCursor &Stream) {
162 if (Stream.EnterSubBlock(clang::serialized_diags::BLOCK_DIAG))
1
Assuming the condition is false
→
2
←
Taking false branch
→
163 return SDError::MalformedDiagnosticBlock;
164
165 std::error_code EC;
166 if ((EC = visitStartOfDiagnostic()))
3
←
Taking false branch
→
167 return EC;
168
169 SmallVector<uint64_t, 16> Record;
170 while (true) {
4
←
Loop condition is true. Entering loop body
→
171 unsigned BlockOrCode = 0;
172 llvm::ErrorOr<Cursor> Res = skipUntilRecordOrBlock(Stream, BlockOrCode);
5
←
Calling 'SerializedDiagnosticReader::skipUntilRecordOrBlock'
→
173 if (!Res)
174 Res.getError();
175
176 switch (Res.get()) {
177 case Cursor::BlockBegin:
178 // The only blocks we care about are subdiagnostics.
179 if (BlockOrCode == serialized_diags::BLOCK_DIAG) {
180 if ((EC = readDiagnosticBlock(Stream)))
181 return EC;
182 } else if (!Stream.SkipBlock())
183 return SDError::MalformedSubBlock;
184 continue;
185 case Cursor::BlockEnd:
186 if ((EC = visitEndOfDiagnostic()))
187 return EC;
188 return {};
189 case Cursor::Record:
190 break;
191 }
192
193 // Read the record.
194 Record.clear();
195 StringRef Blob;
196 unsigned RecID = Stream.readRecord(BlockOrCode, Record, &Blob);
197
198 if (RecID < serialized_diags::RECORD_FIRST ||
199 RecID > serialized_diags::RECORD_LAST)
200 continue;
201
202 switch ((RecordIDs)RecID) {
203 case RECORD_CATEGORY:
204 // A category has ID and name size.
205 if (Record.size() != 2)
206 return SDError::MalformedDiagnosticRecord;
207 if ((EC = visitCategoryRecord(Record[0], Blob)))
208 return EC;
209 continue;
210 case RECORD_DIAG:
211 // A diagnostic has severity, location (4), category, flag, and message
212 // size.
213 if (Record.size() != 8)
214 return SDError::MalformedDiagnosticRecord;
215 if ((EC = visitDiagnosticRecord(
216 Record[0], Location(Record[1], Record[2], Record[3], Record[4]),
217 Record[5], Record[6], Blob)))
218 return EC;
219 continue;
220 case RECORD_DIAG_FLAG:
221 // A diagnostic flag has ID and name size.
222 if (Record.size() != 2)
223 return SDError::MalformedDiagnosticRecord;
224 if ((EC = visitDiagFlagRecord(Record[0], Blob)))
225 return EC;
226 continue;
227 case RECORD_FILENAME:
228 // A filename has ID, size, timestamp, and name size. The size and
229 // timestamp are legacy fields that are always zero these days.
230 if (Record.size() != 4)
231 return SDError::MalformedDiagnosticRecord;
232 if ((EC = visitFilenameRecord(Record[0], Record[1], Record[2], Blob)))
233 return EC;
234 continue;
235 case RECORD_FIXIT:
236 // A fixit has two locations (4 each) and message size.
237 if (Record.size() != 9)
238 return SDError::MalformedDiagnosticRecord;
239 if ((EC = visitFixitRecord(
240 Location(Record[0], Record[1], Record[2], Record[3]),
241 Location(Record[4], Record[5], Record[6], Record[7]), Blob)))
242 return EC;
243 continue;
244 case RECORD_SOURCE_RANGE:
245 // A source range is two locations (4 each).
246 if (Record.size() != 8)
247 return SDError::MalformedDiagnosticRecord;
248 if ((EC = visitSourceRangeRecord(
249 Location(Record[0], Record[1], Record[2], Record[3]),
250 Location(Record[4], Record[5], Record[6], Record[7]))))
251 return EC;
252 continue;
253 case RECORD_VERSION:
254 // A version is just a number.
255 if (Record.size() != 1)
256 return SDError::MalformedDiagnosticRecord;
257 if ((EC = visitVersionRecord(Record[0])))
258 return EC;
259 continue;
260 }
261 }
262}
263
264namespace {
265
266class SDErrorCategoryType final : public std::error_category {
267 const char *name() const noexcept override {
268 return "clang.serialized_diags";
269 }
270
271 std::string message(int IE) const override {
272 auto E = static_cast<SDError>(IE);
273 switch (E) {
274 case SDError::CouldNotLoad:
275 return "Failed to open diagnostics file";
276 case SDError::InvalidSignature:
277 return "Invalid diagnostics signature";
278 case SDError::InvalidDiagnostics:
279 return "Parse error reading diagnostics";
280 case SDError::MalformedTopLevelBlock:
281 return "Malformed block at top-level of diagnostics";
282 case SDError::MalformedSubBlock:
283 return "Malformed sub-block in a diagnostic";
284 case SDError::MalformedBlockInfoBlock:
285 return "Malformed BlockInfo block";
286 case SDError::MalformedMetadataBlock:
287 return "Malformed Metadata block";
288 case SDError::MalformedDiagnosticBlock:
289 return "Malformed Diagnostic block";
290 case SDError::MalformedDiagnosticRecord:
291 return "Malformed Diagnostic record";
292 case SDError::MissingVersion:
293 return "No version provided in diagnostics";
294 case SDError::VersionMismatch:
295 return "Unsupported diagnostics version";
296 case SDError::UnsupportedConstruct:
297 return "Bitcode constructs that are not supported in diagnostics appear";
298 case SDError::HandlerFailed:
299 return "Generic error occurred while handling a record";
300 }
301 llvm_unreachable("Unknown error type!")::llvm::llvm_unreachable_internal("Unknown error type!", "/build/llvm-toolchain-snapshot-9~svn362543/tools/clang/lib/Frontend/SerializedDiagnosticReader.cpp"
, 301);
302 }
303};
304
305} // namespace
306
307static llvm::ManagedStatic<SDErrorCategoryType> ErrorCategory;
308const std::error_category &clang::serialized_diags::SDErrorCategory() {
309 return *ErrorCategory;
310}
←

/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Bitcode/BitstreamReader.h

1//===- BitstreamReader.h - Low-level bitstream reader interface -*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This header defines the BitstreamReader class. This class can be used to
10// read an arbitrary bitstream, regardless of its contents.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_BITCODE_BITSTREAMREADER_H
15#define LLVM_BITCODE_BITSTREAMREADER_H
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/Bitcode/BitCodes.h"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/ErrorHandling.h"
22#include "llvm/Support/MathExtras.h"
23#include "llvm/Support/MemoryBuffer.h"
24#include <algorithm>
25#include <cassert>
26#include <climits>
27#include <cstddef>
28#include <cstdint>
29#include <memory>
30#include <string>
31#include <utility>
32#include <vector>
33
34namespace llvm {
35
36/// This class maintains the abbreviations read from a block info block.
37class BitstreamBlockInfo {
38public:
39 /// This contains information emitted to BLOCKINFO_BLOCK blocks. These
40 /// describe abbreviations that all blocks of the specified ID inherit.
41 struct BlockInfo {
42 unsigned BlockID;
43 std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs;
44 std::string Name;
45 std::vector<std::pair<unsigned, std::string>> RecordNames;
46 };
47
48private:
49 std::vector<BlockInfo> BlockInfoRecords;
50
51public:
52 /// If there is block info for the specified ID, return it, otherwise return
53 /// null.
54 const BlockInfo *getBlockInfo(unsigned BlockID) const {
55 // Common case, the most recent entry matches BlockID.
56 if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
57 return &BlockInfoRecords.back();
58
59 for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
60 i != e; ++i)
61 if (BlockInfoRecords[i].BlockID == BlockID)
62 return &BlockInfoRecords[i];
63 return nullptr;
64 }
65
66 BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
67 if (const BlockInfo *BI = getBlockInfo(BlockID))
68 return *const_cast<BlockInfo*>(BI);
69
70 // Otherwise, add a new record.
71 BlockInfoRecords.emplace_back();
72 BlockInfoRecords.back().BlockID = BlockID;
73 return BlockInfoRecords.back();
74 }
75};
76
77/// This represents a position within a bitstream. There may be multiple
78/// independent cursors reading within one bitstream, each maintaining their
79/// own local state.
80class SimpleBitstreamCursor {
81 ArrayRef<uint8_t> BitcodeBytes;
82 size_t NextChar = 0;
83
84public:
85 /// This is the current data we have pulled from the stream but have not
86 /// returned to the client. This is specifically and intentionally defined to
87 /// follow the word size of the host machine for efficiency. We use word_t in
88 /// places that are aware of this to make it perfectly explicit what is going
89 /// on.
90 using word_t = size_t;
91
92private:
93 word_t CurWord = 0;
94
95 /// This is the number of bits in CurWord that are valid. This is always from
96 /// [0...bits_of(size_t)-1] inclusive.
97 unsigned BitsInCurWord = 0;
98
99public:
100 static const size_t MaxChunkSize = sizeof(word_t) * 8;
101
102 SimpleBitstreamCursor() = default;
103 explicit SimpleBitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
104 : BitcodeBytes(BitcodeBytes) {}
105 explicit SimpleBitstreamCursor(StringRef BitcodeBytes)
106 : BitcodeBytes(arrayRefFromStringRef(BitcodeBytes)) {}
107 explicit SimpleBitstreamCursor(MemoryBufferRef BitcodeBytes)
108 : SimpleBitstreamCursor(BitcodeBytes.getBuffer()) {}
109
110 bool canSkipToPos(size_t pos) const {
111 // pos can be skipped to if it is a valid address or one byte past the end.
112 return pos <= BitcodeBytes.size();
113 }
114
115 bool AtEndOfStream() {
116 return BitsInCurWord == 0 && BitcodeBytes.size() <= NextChar;
117 }
118
119 /// Return the bit # of the bit we are reading.
120 uint64_t GetCurrentBitNo() const {
121 return NextChar*CHAR_BIT8 - BitsInCurWord;
122 }
123
124 // Return the byte # of the current bit.
125 uint64_t getCurrentByteNo() const { return GetCurrentBitNo() / 8; }
126
127 ArrayRef<uint8_t> getBitcodeBytes() const { return BitcodeBytes; }
128
129 /// Reset the stream to the specified bit number.
130 void JumpToBit(uint64_t BitNo) {
131 size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
132 unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
133 assert(canSkipToPos(ByteNo) && "Invalid location")((canSkipToPos(ByteNo) && "Invalid location") ? static_cast
<void> (0) : __assert_fail ("canSkipToPos(ByteNo) && \"Invalid location\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Bitcode/BitstreamReader.h"
, 133, __PRETTY_FUNCTION__));
134
135 // Move the cursor to the right word.
136 NextChar = ByteNo;
137 BitsInCurWord = 0;
138
139 // Skip over any bits that are already consumed.
140 if (WordBitNo)
141 Read(WordBitNo);
142 }
143
144 /// Get a pointer into the bitstream at the specified byte offset.
145 const uint8_t *getPointerToByte(uint64_t ByteNo, uint64_t NumBytes) {
146 return BitcodeBytes.data() + ByteNo;
147 }
148
149 /// Get a pointer into the bitstream at the specified bit offset.
150 ///
151 /// The bit offset must be on a byte boundary.
152 const uint8_t *getPointerToBit(uint64_t BitNo, uint64_t NumBytes) {
153 assert(!(BitNo % 8) && "Expected bit on byte boundary")((!(BitNo % 8) && "Expected bit on byte boundary") ? static_cast
<void> (0) : __assert_fail ("!(BitNo % 8) && \"Expected bit on byte boundary\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Bitcode/BitstreamReader.h"
, 153, __PRETTY_FUNCTION__));
154 return getPointerToByte(BitNo / 8, NumBytes);
155 }
156
157 void fillCurWord() {
158 if (NextChar >= BitcodeBytes.size())
159 report_fatal_error("Unexpected end of file");
160
161 // Read the next word from the stream.
162 const uint8_t *NextCharPtr = BitcodeBytes.data() + NextChar;
163 unsigned BytesRead;
164 if (BitcodeBytes.size() >= NextChar + sizeof(word_t)) {
165 BytesRead = sizeof(word_t);
166 CurWord =
167 support::endian::read<word_t, support::little, support::unaligned>(
168 NextCharPtr);
169 } else {
170 // Short read.
171 BytesRead = BitcodeBytes.size() - NextChar;
172 CurWord = 0;
173 for (unsigned B = 0; B != BytesRead; ++B)
174 CurWord |= uint64_t(NextCharPtr[B]) << (B * 8);
175 }
176 NextChar += BytesRead;
177 BitsInCurWord = BytesRead * 8;
178 }
179
180 word_t Read(unsigned NumBits) {
181 static const unsigned BitsInWord = MaxChunkSize;
182
183 assert(NumBits && NumBits <= BitsInWord &&((NumBits && NumBits <= BitsInWord && "Cannot return zero or more than BitsInWord bits!"
) ? static_cast<void> (0) : __assert_fail ("NumBits && NumBits <= BitsInWord && \"Cannot return zero or more than BitsInWord bits!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Bitcode/BitstreamReader.h"
, 184, __PRETTY_FUNCTION__))
9
←
Assuming 'NumBits' is not equal to 0
→
10
←
Assuming 'NumBits' is <= 'BitsInWord'
→
11
←
'?' condition is true
→
184 "Cannot return zero or more than BitsInWord bits!")((NumBits && NumBits <= BitsInWord && "Cannot return zero or more than BitsInWord bits!"
) ? static_cast<void> (0) : __assert_fail ("NumBits && NumBits <= BitsInWord && \"Cannot return zero or more than BitsInWord bits!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Bitcode/BitstreamReader.h"
, 184, __PRETTY_FUNCTION__));
185
186 static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
12
←
'?' condition is true
→
187
188 // If the field is fully contained by CurWord, return it quickly.
189 if (BitsInCurWord >= NumBits) {
13
←
Assuming the condition is false
→
14
←
Taking false branch
→
190 word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));
191
192 // Use a mask to avoid undefined behavior.
193 CurWord >>= (NumBits & Mask);
194
195 BitsInCurWord -= NumBits;
196 return R;
197 }
198
199 word_t R = BitsInCurWord ? CurWord : 0;
15
←
'?' condition is true
→
200 unsigned BitsLeft = NumBits - BitsInCurWord;
201
202 fillCurWord();
203
204 // If we run out of data, abort.
205 if (BitsLeft > BitsInCurWord)
16
←
Assuming the condition is false
→
17
←
Taking false branch
→
206 report_fatal_error("Unexpected end of file");
207
208 word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
18
←
The result of the right shift is undefined due to shifting by '64', which is greater or equal to the width of type 'llvm::SimpleBitstreamCursor::word_t'
209
210 // Use a mask to avoid undefined behavior.
211 CurWord >>= (BitsLeft & Mask);
212
213 BitsInCurWord -= BitsLeft;
214
215 R |= R2 << (NumBits - BitsLeft);
216
217 return R;
218 }
219
220 uint32_t ReadVBR(unsigned NumBits) {
221 uint32_t Piece = Read(NumBits);
222 if ((Piece & (1U << (NumBits-1))) == 0)
223 return Piece;
224
225 uint32_t Result = 0;
226 unsigned NextBit = 0;
227 while (true) {
228 Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;
229
230 if ((Piece & (1U << (NumBits-1))) == 0)
231 return Result;
232
233 NextBit += NumBits-1;
234 Piece = Read(NumBits);
235 }
236 }
237
238 // Read a VBR that may have a value up to 64-bits in size. The chunk size of
239 // the VBR must still be <= 32 bits though.
240 uint64_t ReadVBR64(unsigned NumBits) {
241 uint32_t Piece = Read(NumBits);
242 if ((Piece & (1U << (NumBits-1))) == 0)
243 return uint64_t(Piece);
244
245 uint64_t Result = 0;
246 unsigned NextBit = 0;
247 while (true) {
248 Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
249
250 if ((Piece & (1U << (NumBits-1))) == 0)
251 return Result;
252
253 NextBit += NumBits-1;
254 Piece = Read(NumBits);
255 }
256 }
257
258 void SkipToFourByteBoundary() {
259 // If word_t is 64-bits and if we've read less than 32 bits, just dump
260 // the bits we have up to the next 32-bit boundary.
261 if (sizeof(word_t) > 4 &&
262 BitsInCurWord >= 32) {
263 CurWord >>= BitsInCurWord-32;
264 BitsInCurWord = 32;
265 return;
266 }
267
268 BitsInCurWord = 0;
269 }
270
271 /// Skip to the end of the file.
272 void skipToEnd() { NextChar = BitcodeBytes.size(); }
273};
274
275/// When advancing through a bitstream cursor, each advance can discover a few
276/// different kinds of entries:
277struct BitstreamEntry {
278 enum {
279 Error, // Malformed bitcode was found.
280 EndBlock, // We've reached the end of the current block, (or the end of the
281 // file, which is treated like a series of EndBlock records.
282 SubBlock, // This is the start of a new subblock of a specific ID.
283 Record // This is a record with a specific AbbrevID.
284 } Kind;
285
286 unsigned ID;
287
288 static BitstreamEntry getError() {
289 BitstreamEntry E; E.Kind = Error; return E;
290 }
291
292 static BitstreamEntry getEndBlock() {
293 BitstreamEntry E; E.Kind = EndBlock; return E;
294 }
295
296 static BitstreamEntry getSubBlock(unsigned ID) {
297 BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
298 }
299
300 static BitstreamEntry getRecord(unsigned AbbrevID) {
301 BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
302 }
303};
304
305/// This represents a position within a bitcode file, implemented on top of a
306/// SimpleBitstreamCursor.
307///
308/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
309/// be passed by value.
310class BitstreamCursor : SimpleBitstreamCursor {
311 // This is the declared size of code values used for the current block, in
312 // bits.
313 unsigned CurCodeSize = 2;
314
315 /// Abbrevs installed at in this block.
316 std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;
317
318 struct Block {
319 unsigned PrevCodeSize;
320 std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;
321
322 explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
323 };
324
325 /// This tracks the codesize of parent blocks.
326 SmallVector<Block, 8> BlockScope;
327
328 BitstreamBlockInfo *BlockInfo = nullptr;
329
330public:
331 static const size_t MaxChunkSize = sizeof(word_t) * 8;
332
333 BitstreamCursor() = default;
334 explicit BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
335 : SimpleBitstreamCursor(BitcodeBytes) {}
336 explicit BitstreamCursor(StringRef BitcodeBytes)
337 : SimpleBitstreamCursor(BitcodeBytes) {}
338 explicit BitstreamCursor(MemoryBufferRef BitcodeBytes)
339 : SimpleBitstreamCursor(BitcodeBytes) {}
340
341 using SimpleBitstreamCursor::canSkipToPos;
342 using SimpleBitstreamCursor::AtEndOfStream;
343 using SimpleBitstreamCursor::getBitcodeBytes;
344 using SimpleBitstreamCursor::GetCurrentBitNo;
345 using SimpleBitstreamCursor::getCurrentByteNo;
346 using SimpleBitstreamCursor::getPointerToByte;
347 using SimpleBitstreamCursor::JumpToBit;
348 using SimpleBitstreamCursor::fillCurWord;
349 using SimpleBitstreamCursor::Read;
350 using SimpleBitstreamCursor::ReadVBR;
351 using SimpleBitstreamCursor::ReadVBR64;
352
353 /// Return the number of bits used to encode an abbrev #.
354 unsigned getAbbrevIDWidth() const { return CurCodeSize; }
355
356 /// Flags that modify the behavior of advance().
357 enum {
358 /// If this flag is used, the advance() method does not automatically pop
359 /// the block scope when the end of a block is reached.
360 AF_DontPopBlockAtEnd = 1,
361
362 /// If this flag is used, abbrev entries are returned just like normal
363 /// records.
364 AF_DontAutoprocessAbbrevs = 2
365 };
366
367 /// Advance the current bitstream, returning the next entry in the stream.
368 BitstreamEntry advance(unsigned Flags = 0) {
369 while (true) {
370 if (AtEndOfStream())
371 return BitstreamEntry::getError();
372
373 unsigned Code = ReadCode();
374 if (Code == bitc::END_BLOCK) {
375 // Pop the end of the block unless Flags tells us not to.
376 if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
377 return BitstreamEntry::getError();
378 return BitstreamEntry::getEndBlock();
379 }
380
381 if (Code == bitc::ENTER_SUBBLOCK)
382 return BitstreamEntry::getSubBlock(ReadSubBlockID());
383
384 if (Code == bitc::DEFINE_ABBREV &&
385 !(Flags & AF_DontAutoprocessAbbrevs)) {
386 // We read and accumulate abbrev's, the client can't do anything with
387 // them anyway.
388 ReadAbbrevRecord();
389 continue;
390 }
391
392 return BitstreamEntry::getRecord(Code);
393 }
394 }
395
396 /// This is a convenience function for clients that don't expect any
397 /// subblocks. This just skips over them automatically.
398 BitstreamEntry advanceSkippingSubblocks(unsigned Flags = 0) {
399 while (true) {
400 // If we found a normal entry, return it.
401 BitstreamEntry Entry = advance(Flags);
402 if (Entry.Kind != BitstreamEntry::SubBlock)
403 return Entry;
404
405 // If we found a sub-block, just skip over it and check the next entry.
406 if (SkipBlock())
407 return BitstreamEntry::getError();
408 }
409 }
410
411 unsigned ReadCode() {
412 return Read(CurCodeSize);
8
←
Calling 'SimpleBitstreamCursor::Read'
→
413 }
414
415 // Block header:
416 // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
417
418 /// Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
419 unsigned ReadSubBlockID() {
420 return ReadVBR(bitc::BlockIDWidth);
421 }
422
423 /// Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body
424 /// of this block. If the block record is malformed, return true.
425 bool SkipBlock() {
426 // Read and ignore the codelen value. Since we are skipping this block, we
427 // don't care what code widths are used inside of it.
428 ReadVBR(bitc::CodeLenWidth);
429 SkipToFourByteBoundary();
430 size_t NumFourBytes = Read(bitc::BlockSizeWidth);
431
432 // Check that the block wasn't partially defined, and that the offset isn't
433 // bogus.
434 size_t SkipTo = GetCurrentBitNo() + NumFourBytes*4*8;
435 if (AtEndOfStream() || !canSkipToPos(SkipTo/8))
436 return true;
437
438 JumpToBit(SkipTo);
439 return false;
440 }
441
442 /// Having read the ENTER_SUBBLOCK abbrevid, enter the block, and return true
443 /// if the block has an error.
444 bool EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
445
446 bool ReadBlockEnd() {
447 if (BlockScope.empty()) return true;
448
449 // Block tail:
450 // [END_BLOCK, <align4bytes>]
451 SkipToFourByteBoundary();
452
453 popBlockScope();
454 return false;
455 }
456
457private:
458 void popBlockScope() {
459 CurCodeSize = BlockScope.back().PrevCodeSize;
460
461 CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
462 BlockScope.pop_back();
463 }
464
465 //===--------------------------------------------------------------------===//
466 // Record Processing
467 //===--------------------------------------------------------------------===//
468
469public:
470 /// Return the abbreviation for the specified AbbrevId.
471 const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
472 unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
473 if (AbbrevNo >= CurAbbrevs.size())
474 report_fatal_error("Invalid abbrev number");
475 return CurAbbrevs[AbbrevNo].get();
476 }
477
478 /// Read the current record and discard it, returning the code for the record.
479 unsigned skipRecord(unsigned AbbrevID);
480
481 unsigned readRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
482 StringRef *Blob = nullptr);
483
484 //===--------------------------------------------------------------------===//
485 // Abbrev Processing
486 //===--------------------------------------------------------------------===//
487 void ReadAbbrevRecord();
488
489 /// Read and return a block info block from the bitstream. If an error was
490 /// encountered, return None.
491 ///
492 /// \param ReadBlockInfoNames Whether to read block/record name information in
493 /// the BlockInfo block. Only llvm-bcanalyzer uses this.
494 Optional<BitstreamBlockInfo>
495 ReadBlockInfoBlock(bool ReadBlockInfoNames = false);
496
497 /// Set the block info to be used by this BitstreamCursor to interpret
498 /// abbreviated records.
499 void setBlockInfo(BitstreamBlockInfo *BI) { BlockInfo = BI; }
500};
501
502} // end llvm namespace
503
504#endif // LLVM_BITCODE_BITSTREAMREADER_H