Bug Summary

File:src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitstream/BitstreamReader.h
Warning:line 200, column 40
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

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name BitstreamRemarkParser.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 -setup-static-analyzer -mrelocation-model pic -pic-level 1 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Analysis -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ASMParser -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/BinaryFormat -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitcode -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitcode -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitstream -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /include/llvm/CodeGen -I /include/llvm/CodeGen/PBQP -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/IR -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IR -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Coroutines -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData/Coverage -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/CodeView -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/DWARF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/MSF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/PDB -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Demangle -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/JITLink -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/Orc -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenACC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenMP -I /include/llvm/CodeGen/GlobalISel -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IRReader -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/LTO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Linker -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC/MCParser -I /include/llvm/CodeGen/MIRParser -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Object -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Option -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Passes -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Scalar -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ADT -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/Symbolize -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Target -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Utils -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Vectorize -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/IPO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libLLVM/../include -I /usr/src/gnu/usr.bin/clang/libLLVM/obj -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -D PIC -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -D_RET_PROTECTOR -ret-protector -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Remarks/BitstreamRemarkParser.cpp

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Remarks/BitstreamRemarkParser.cpp

→
1//===- BitstreamRemarkParser.cpp ------------------------------------------===//
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 file provides utility methods used by clients that want to use the
10// parser for remark diagnostics in LLVM.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Remarks/BitstreamRemarkParser.h"
15#include "BitstreamRemarkParser.h"
16#include "llvm/Support/MemoryBuffer.h"
17#include "llvm/Support/Path.h"
18
19using namespace llvm;
20using namespace llvm::remarks;
21
22static Error unknownRecord(const char *BlockName, unsigned RecordID) {
23 return createStringError(
24 std::make_error_code(std::errc::illegal_byte_sequence),
25 "Error while parsing %s: unknown record entry (%lu).", BlockName,
26 RecordID);
27}
28
29static Error malformedRecord(const char *BlockName, const char *RecordName) {
30 return createStringError(
31 std::make_error_code(std::errc::illegal_byte_sequence),
32 "Error while parsing %s: malformed record entry (%s).", BlockName,
33 RecordName);
34}
35
36BitstreamMetaParserHelper::BitstreamMetaParserHelper(
37 BitstreamCursor &Stream, BitstreamBlockInfo &BlockInfo)
38 : Stream(Stream), BlockInfo(BlockInfo) {}
39
40/// Parse a record and fill in the fields in the parser.
41static Error parseRecord(BitstreamMetaParserHelper &Parser, unsigned Code) {
42 BitstreamCursor &Stream = Parser.Stream;
43 // Note: 2 is used here because it's the max number of fields we have per
44 // record.
45 SmallVector<uint64_t, 2> Record;
46 StringRef Blob;
47 Expected<unsigned> RecordID = Stream.readRecord(Code, Record, &Blob);
48 if (!RecordID)
49 return RecordID.takeError();
50
51 switch (*RecordID) {
52 case RECORD_META_CONTAINER_INFO: {
53 if (Record.size() != 2)
54 return malformedRecord("BLOCK_META", "RECORD_META_CONTAINER_INFO");
55 Parser.ContainerVersion = Record[0];
56 Parser.ContainerType = Record[1];
57 break;
58 }
59 case RECORD_META_REMARK_VERSION: {
60 if (Record.size() != 1)
61 return malformedRecord("BLOCK_META", "RECORD_META_REMARK_VERSION");
62 Parser.RemarkVersion = Record[0];
63 break;
64 }
65 case RECORD_META_STRTAB: {
66 if (Record.size() != 0)
67 return malformedRecord("BLOCK_META", "RECORD_META_STRTAB");
68 Parser.StrTabBuf = Blob;
69 break;
70 }
71 case RECORD_META_EXTERNAL_FILE: {
72 if (Record.size() != 0)
73 return malformedRecord("BLOCK_META", "RECORD_META_EXTERNAL_FILE");
74 Parser.ExternalFilePath = Blob;
75 break;
76 }
77 default:
78 return unknownRecord("BLOCK_META", *RecordID);
79 }
80 return Error::success();
81}
82
83BitstreamRemarkParserHelper::BitstreamRemarkParserHelper(
84 BitstreamCursor &Stream)
85 : Stream(Stream) {}
86
87/// Parse a record and fill in the fields in the parser.
88static Error parseRecord(BitstreamRemarkParserHelper &Parser, unsigned Code) {
89 BitstreamCursor &Stream = Parser.Stream;
90 // Note: 5 is used here because it's the max number of fields we have per
91 // record.
92 SmallVector<uint64_t, 5> Record;
93 StringRef Blob;
94 Expected<unsigned> RecordID = Stream.readRecord(Code, Record, &Blob);
95 if (!RecordID)
96 return RecordID.takeError();
97
98 switch (*RecordID) {
99 case RECORD_REMARK_HEADER: {
100 if (Record.size() != 4)
101 return malformedRecord("BLOCK_REMARK", "RECORD_REMARK_HEADER");
102 Parser.Type = Record[0];
103 Parser.RemarkNameIdx = Record[1];
104 Parser.PassNameIdx = Record[2];
105 Parser.FunctionNameIdx = Record[3];
106 break;
107 }
108 case RECORD_REMARK_DEBUG_LOC: {
109 if (Record.size() != 3)
110 return malformedRecord("BLOCK_REMARK", "RECORD_REMARK_DEBUG_LOC");
111 Parser.SourceFileNameIdx = Record[0];
112 Parser.SourceLine = Record[1];
113 Parser.SourceColumn = Record[2];
114 break;
115 }
116 case RECORD_REMARK_HOTNESS: {
117 if (Record.size() != 1)
118 return malformedRecord("BLOCK_REMARK", "RECORD_REMARK_HOTNESS");
119 Parser.Hotness = Record[0];
120 break;
121 }
122 case RECORD_REMARK_ARG_WITH_DEBUGLOC: {
123 if (Record.size() != 5)
124 return malformedRecord("BLOCK_REMARK", "RECORD_REMARK_ARG_WITH_DEBUGLOC");
125 // Create a temporary argument. Use that as a valid memory location for this
126 // argument entry.
127 Parser.TmpArgs.emplace_back();
128 Parser.TmpArgs.back().KeyIdx = Record[0];
129 Parser.TmpArgs.back().ValueIdx = Record[1];
130 Parser.TmpArgs.back().SourceFileNameIdx = Record[2];
131 Parser.TmpArgs.back().SourceLine = Record[3];
132 Parser.TmpArgs.back().SourceColumn = Record[4];
133 Parser.Args =
134 ArrayRef<BitstreamRemarkParserHelper::Argument>(Parser.TmpArgs);
135 break;
136 }
137 case RECORD_REMARK_ARG_WITHOUT_DEBUGLOC: {
138 if (Record.size() != 2)
139 return malformedRecord("BLOCK_REMARK",
140 "RECORD_REMARK_ARG_WITHOUT_DEBUGLOC");
141 // Create a temporary argument. Use that as a valid memory location for this
142 // argument entry.
143 Parser.TmpArgs.emplace_back();
144 Parser.TmpArgs.back().KeyIdx = Record[0];
145 Parser.TmpArgs.back().ValueIdx = Record[1];
146 Parser.Args =
147 ArrayRef<BitstreamRemarkParserHelper::Argument>(Parser.TmpArgs);
148 break;
149 }
150 default:
151 return unknownRecord("BLOCK_REMARK", *RecordID);
152 }
153 return Error::success();
154}
155
156template <typename T>
157static Error parseBlock(T &ParserHelper, unsigned BlockID,
158 const char *BlockName) {
159 BitstreamCursor &Stream = ParserHelper.Stream;
160 Expected<BitstreamEntry> Next = Stream.advance();
7
←
Calling 'BitstreamCursor::advance'
→
161 if (!Next)
162 return Next.takeError();
163 if (Next->Kind != BitstreamEntry::SubBlock || Next->ID != BlockID)
164 return createStringError(
165 std::make_error_code(std::errc::illegal_byte_sequence),
166 "Error while parsing %s: expecting [ENTER_SUBBLOCK, %s, ...].",
167 BlockName, BlockName);
168 if (Stream.EnterSubBlock(BlockID))
169 return createStringError(
170 std::make_error_code(std::errc::illegal_byte_sequence),
171 "Error while entering %s.", BlockName);
172
173 // Stop when there is nothing to read anymore or when we encounter an
174 // END_BLOCK.
175 while (!Stream.AtEndOfStream()) {
176 Next = Stream.advance();
177 if (!Next)
178 return Next.takeError();
179 switch (Next->Kind) {
180 case BitstreamEntry::EndBlock:
181 return Error::success();
182 case BitstreamEntry::Error:
183 case BitstreamEntry::SubBlock:
184 return createStringError(
185 std::make_error_code(std::errc::illegal_byte_sequence),
186 "Error while parsing %s: expecting records.", BlockName);
187 case BitstreamEntry::Record:
188 if (Error E = parseRecord(ParserHelper, Next->ID))
189 return E;
190 continue;
191 }
192 }
193 // If we're here, it means we didn't get an END_BLOCK yet, but we're at the
194 // end of the stream. In this case, error.
195 return createStringError(
196 std::make_error_code(std::errc::illegal_byte_sequence),
197 "Error while parsing %s: unterminated block.", BlockName);
198}
199
200Error BitstreamMetaParserHelper::parse() {
201 return parseBlock(*this, META_BLOCK_ID, "META_BLOCK");
202}
203
204Error BitstreamRemarkParserHelper::parse() {
205 return parseBlock(*this, REMARK_BLOCK_ID, "REMARK_BLOCK");
6
←
Calling 'parseBlock<llvm::remarks::BitstreamRemarkParserHelper>'
→
206}
207
208BitstreamParserHelper::BitstreamParserHelper(StringRef Buffer)
209 : Stream(Buffer) {}
210
211Expected<std::array<char, 4>> BitstreamParserHelper::parseMagic() {
212 std::array<char, 4> Result;
213 for (unsigned i = 0; i < 4; ++i)
214 if (Expected<unsigned> R = Stream.Read(8))
215 Result[i] = *R;
216 else
217 return R.takeError();
218 return Result;
219}
220
221Error BitstreamParserHelper::parseBlockInfoBlock() {
222 Expected<BitstreamEntry> Next = Stream.advance();
223 if (!Next)
224 return Next.takeError();
225 if (Next->Kind != BitstreamEntry::SubBlock ||
226 Next->ID != llvm::bitc::BLOCKINFO_BLOCK_ID)
227 return createStringError(
228 std::make_error_code(std::errc::illegal_byte_sequence),
229 "Error while parsing BLOCKINFO_BLOCK: expecting [ENTER_SUBBLOCK, "
230 "BLOCKINFO_BLOCK, ...].");
231
232 Expected<Optional<BitstreamBlockInfo>> MaybeBlockInfo =
233 Stream.ReadBlockInfoBlock();
234 if (!MaybeBlockInfo)
235 return MaybeBlockInfo.takeError();
236
237 if (!*MaybeBlockInfo)
238 return createStringError(
239 std::make_error_code(std::errc::illegal_byte_sequence),
240 "Error while parsing BLOCKINFO_BLOCK.");
241
242 BlockInfo = **MaybeBlockInfo;
243
244 Stream.setBlockInfo(&BlockInfo);
245 return Error::success();
246}
247
248static Expected<bool> isBlock(BitstreamCursor &Stream, unsigned BlockID) {
249 bool Result = false;
250 uint64_t PreviousBitNo = Stream.GetCurrentBitNo();
251 Expected<BitstreamEntry> Next = Stream.advance();
252 if (!Next)
253 return Next.takeError();
254 switch (Next->Kind) {
255 case BitstreamEntry::SubBlock:
256 // Check for the block id.
257 Result = Next->ID == BlockID;
258 break;
259 case BitstreamEntry::Error:
260 return createStringError(
261 std::make_error_code(std::errc::illegal_byte_sequence),
262 "Unexpected error while parsing bitstream.");
263 default:
264 Result = false;
265 break;
266 }
267 if (Error E = Stream.JumpToBit(PreviousBitNo))
268 return std::move(E);
269 return Result;
270}
271
272Expected<bool> BitstreamParserHelper::isMetaBlock() {
273 return isBlock(Stream, META_BLOCK_ID);
274}
275
276Expected<bool> BitstreamParserHelper::isRemarkBlock() {
277 return isBlock(Stream, META_BLOCK_ID);
278}
279
280static Error validateMagicNumber(StringRef MagicNumber) {
281 if (MagicNumber != remarks::ContainerMagic)
282 return createStringError(std::make_error_code(std::errc::invalid_argument),
283 "Unknown magic number: expecting %s, got %.4s.",
284 remarks::ContainerMagic.data(), MagicNumber.data());
285 return Error::success();
286}
287
288static Error advanceToMetaBlock(BitstreamParserHelper &Helper) {
289 Expected<std::array<char, 4>> MagicNumber = Helper.parseMagic();
290 if (!MagicNumber)
291 return MagicNumber.takeError();
292 if (Error E = validateMagicNumber(
293 StringRef(MagicNumber->data(), MagicNumber->size())))
294 return E;
295 if (Error E = Helper.parseBlockInfoBlock())
296 return E;
297 Expected<bool> isMetaBlock = Helper.isMetaBlock();
298 if (!isMetaBlock)
299 return isMetaBlock.takeError();
300 if (!*isMetaBlock)
301 return createStringError(
302 std::make_error_code(std::errc::illegal_byte_sequence),
303 "Expecting META_BLOCK after the BLOCKINFO_BLOCK.");
304 return Error::success();
305}
306
307Expected<std::unique_ptr<BitstreamRemarkParser>>
308remarks::createBitstreamParserFromMeta(
309 StringRef Buf, Optional<ParsedStringTable> StrTab,
310 Optional<StringRef> ExternalFilePrependPath) {
311 BitstreamParserHelper Helper(Buf);
312 Expected<std::array<char, 4>> MagicNumber = Helper.parseMagic();
313 if (!MagicNumber)
314 return MagicNumber.takeError();
315
316 if (Error E = validateMagicNumber(
317 StringRef(MagicNumber->data(), MagicNumber->size())))
318 return std::move(E);
319
320 auto Parser =
321 StrTab ? std::make_unique<BitstreamRemarkParser>(Buf, std::move(*StrTab))
322 : std::make_unique<BitstreamRemarkParser>(Buf);
323
324 if (ExternalFilePrependPath)
325 Parser->ExternalFilePrependPath = std::string(*ExternalFilePrependPath);
326
327 return std::move(Parser);
328}
329
330Expected<std::unique_ptr<Remark>> BitstreamRemarkParser::next() {
331 if (ParserHelper.atEndOfStream())
1
Taking false branch
→
332 return make_error<EndOfFileError>();
333
334 if (!ReadyToParseRemarks) {
2
←
Assuming field 'ReadyToParseRemarks' is true
→
3
←
Taking false branch
→
335 if (Error E = parseMeta())
336 return std::move(E);
337 ReadyToParseRemarks = true;
338 }
339
340 return parseRemark();
4
←
Calling 'BitstreamRemarkParser::parseRemark'
→
341}
342
343Error BitstreamRemarkParser::parseMeta() {
344 // Advance and to the meta block.
345 if (Error E = advanceToMetaBlock(ParserHelper))
346 return E;
347
348 BitstreamMetaParserHelper MetaHelper(ParserHelper.Stream,
349 ParserHelper.BlockInfo);
350 if (Error E = MetaHelper.parse())
351 return E;
352
353 if (Error E = processCommonMeta(MetaHelper))
354 return E;
355
356 switch (ContainerType) {
357 case BitstreamRemarkContainerType::Standalone:
358 return processStandaloneMeta(MetaHelper);
359 case BitstreamRemarkContainerType::SeparateRemarksFile:
360 return processSeparateRemarksFileMeta(MetaHelper);
361 case BitstreamRemarkContainerType::SeparateRemarksMeta:
362 return processSeparateRemarksMetaMeta(MetaHelper);
363 }
364 llvm_unreachable("Unknown BitstreamRemarkContainerType enum")__builtin_unreachable();
365}
366
367Error BitstreamRemarkParser::processCommonMeta(
368 BitstreamMetaParserHelper &Helper) {
369 if (Optional<uint64_t> Version = Helper.ContainerVersion)
370 ContainerVersion = *Version;
371 else
372 return createStringError(
373 std::make_error_code(std::errc::illegal_byte_sequence),
374 "Error while parsing BLOCK_META: missing container version.");
375
376 if (Optional<uint8_t> Type = Helper.ContainerType) {
377 // Always >= BitstreamRemarkContainerType::First since it's unsigned.
378 if (*Type > static_cast<uint8_t>(BitstreamRemarkContainerType::Last))
379 return createStringError(
380 std::make_error_code(std::errc::illegal_byte_sequence),
381 "Error while parsing BLOCK_META: invalid container type.");
382
383 ContainerType = static_cast<BitstreamRemarkContainerType>(*Type);
384 } else
385 return createStringError(
386 std::make_error_code(std::errc::illegal_byte_sequence),
387 "Error while parsing BLOCK_META: missing container type.");
388
389 return Error::success();
390}
391
392static Error processStrTab(BitstreamRemarkParser &P,
393 Optional<StringRef> StrTabBuf) {
394 if (!StrTabBuf)
395 return createStringError(
396 std::make_error_code(std::errc::illegal_byte_sequence),
397 "Error while parsing BLOCK_META: missing string table.");
398 // Parse and assign the string table.
399 P.StrTab.emplace(*StrTabBuf);
400 return Error::success();
401}
402
403static Error processRemarkVersion(BitstreamRemarkParser &P,
404 Optional<uint64_t> RemarkVersion) {
405 if (!RemarkVersion)
406 return createStringError(
407 std::make_error_code(std::errc::illegal_byte_sequence),
408 "Error while parsing BLOCK_META: missing remark version.");
409 P.RemarkVersion = *RemarkVersion;
410 return Error::success();
411}
412
413Error BitstreamRemarkParser::processExternalFilePath(
414 Optional<StringRef> ExternalFilePath) {
415 if (!ExternalFilePath)
416 return createStringError(
417 std::make_error_code(std::errc::illegal_byte_sequence),
418 "Error while parsing BLOCK_META: missing external file path.");
419
420 SmallString<80> FullPath(ExternalFilePrependPath);
421 sys::path::append(FullPath, *ExternalFilePath);
422
423 // External file: open the external file, parse it, check if its metadata
424 // matches the one from the separate metadata, then replace the current parser
425 // with the one parsing the remarks.
426 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
427 MemoryBuffer::getFile(FullPath);
428 if (std::error_code EC = BufferOrErr.getError())
429 return createFileError(FullPath, EC);
430
431 TmpRemarkBuffer = std::move(*BufferOrErr);
432
433 // Don't try to parse the file if it's empty.
434 if (TmpRemarkBuffer->getBufferSize() == 0)
435 return make_error<EndOfFileError>();
436
437 // Create a separate parser used for parsing the separate file.
438 ParserHelper = BitstreamParserHelper(TmpRemarkBuffer->getBuffer());
439 // Advance and check until we can parse the meta block.
440 if (Error E = advanceToMetaBlock(ParserHelper))
441 return E;
442 // Parse the meta from the separate file.
443 // Note: here we overwrite the BlockInfo with the one from the file. This will
444 // be used to parse the rest of the file.
445 BitstreamMetaParserHelper SeparateMetaHelper(ParserHelper.Stream,
446 ParserHelper.BlockInfo);
447 if (Error E = SeparateMetaHelper.parse())
448 return E;
449
450 uint64_t PreviousContainerVersion = ContainerVersion;
451 if (Error E = processCommonMeta(SeparateMetaHelper))
452 return E;
453
454 if (ContainerType != BitstreamRemarkContainerType::SeparateRemarksFile)
455 return createStringError(
456 std::make_error_code(std::errc::illegal_byte_sequence),
457 "Error while parsing external file's BLOCK_META: wrong container "
458 "type.");
459
460 if (PreviousContainerVersion != ContainerVersion)
461 return createStringError(
462 std::make_error_code(std::errc::illegal_byte_sequence),
463 "Error while parsing external file's BLOCK_META: mismatching versions: "
464 "original meta: %lu, external file meta: %lu.",
465 PreviousContainerVersion, ContainerVersion);
466
467 // Process the meta from the separate file.
468 return processSeparateRemarksFileMeta(SeparateMetaHelper);
469}
470
471Error BitstreamRemarkParser::processStandaloneMeta(
472 BitstreamMetaParserHelper &Helper) {
473 if (Error E = processStrTab(*this, Helper.StrTabBuf))
474 return E;
475 return processRemarkVersion(*this, Helper.RemarkVersion);
476}
477
478Error BitstreamRemarkParser::processSeparateRemarksFileMeta(
479 BitstreamMetaParserHelper &Helper) {
480 return processRemarkVersion(*this, Helper.RemarkVersion);
481}
482
483Error BitstreamRemarkParser::processSeparateRemarksMetaMeta(
484 BitstreamMetaParserHelper &Helper) {
485 if (Error E = processStrTab(*this, Helper.StrTabBuf))
486 return E;
487 return processExternalFilePath(Helper.ExternalFilePath);
488}
489
490Expected<std::unique_ptr<Remark>> BitstreamRemarkParser::parseRemark() {
491 BitstreamRemarkParserHelper RemarkHelper(ParserHelper.Stream);
492 if (Error E = RemarkHelper.parse())
5
←
Calling 'BitstreamRemarkParserHelper::parse'
→
493 return std::move(E);
494
495 return processRemark(RemarkHelper);
496}
497
498Expected<std::unique_ptr<Remark>>
499BitstreamRemarkParser::processRemark(BitstreamRemarkParserHelper &Helper) {
500 std::unique_ptr<Remark> Result = std::make_unique<Remark>();
501 Remark &R = *Result;
502
503 if (StrTab == None)
504 return createStringError(
505 std::make_error_code(std::errc::invalid_argument),
506 "Error while parsing BLOCK_REMARK: missing string table.");
507
508 if (!Helper.Type)
509 return createStringError(
510 std::make_error_code(std::errc::illegal_byte_sequence),
511 "Error while parsing BLOCK_REMARK: missing remark type.");
512
513 // Always >= Type::First since it's unsigned.
514 if (*Helper.Type > static_cast<uint8_t>(Type::Last))
515 return createStringError(
516 std::make_error_code(std::errc::illegal_byte_sequence),
517 "Error while parsing BLOCK_REMARK: unknown remark type.");
518
519 R.RemarkType = static_cast<Type>(*Helper.Type);
520
521 if (!Helper.RemarkNameIdx)
522 return createStringError(
523 std::make_error_code(std::errc::illegal_byte_sequence),
524 "Error while parsing BLOCK_REMARK: missing remark name.");
525
526 if (Expected<StringRef> RemarkName = (*StrTab)[*Helper.RemarkNameIdx])
527 R.RemarkName = *RemarkName;
528 else
529 return RemarkName.takeError();
530
531 if (!Helper.PassNameIdx)
532 return createStringError(
533 std::make_error_code(std::errc::illegal_byte_sequence),
534 "Error while parsing BLOCK_REMARK: missing remark pass.");
535
536 if (Expected<StringRef> PassName = (*StrTab)[*Helper.PassNameIdx])
537 R.PassName = *PassName;
538 else
539 return PassName.takeError();
540
541 if (!Helper.FunctionNameIdx)
542 return createStringError(
543 std::make_error_code(std::errc::illegal_byte_sequence),
544 "Error while parsing BLOCK_REMARK: missing remark function name.");
545 if (Expected<StringRef> FunctionName = (*StrTab)[*Helper.FunctionNameIdx])
546 R.FunctionName = *FunctionName;
547 else
548 return FunctionName.takeError();
549
550 if (Helper.SourceFileNameIdx && Helper.SourceLine && Helper.SourceColumn) {
551 Expected<StringRef> SourceFileName = (*StrTab)[*Helper.SourceFileNameIdx];
552 if (!SourceFileName)
553 return SourceFileName.takeError();
554 R.Loc.emplace();
555 R.Loc->SourceFilePath = *SourceFileName;
556 R.Loc->SourceLine = *Helper.SourceLine;
557 R.Loc->SourceColumn = *Helper.SourceColumn;
558 }
559
560 if (Helper.Hotness)
561 R.Hotness = *Helper.Hotness;
562
563 if (!Helper.Args)
564 return std::move(Result);
565
566 for (const BitstreamRemarkParserHelper::Argument &Arg : *Helper.Args) {
567 if (!Arg.KeyIdx)
568 return createStringError(
569 std::make_error_code(std::errc::illegal_byte_sequence),
570 "Error while parsing BLOCK_REMARK: missing key in remark argument.");
571 if (!Arg.ValueIdx)
572 return createStringError(
573 std::make_error_code(std::errc::illegal_byte_sequence),
574 "Error while parsing BLOCK_REMARK: missing value in remark "
575 "argument.");
576
577 // We have at least a key and a value, create an entry.
578 R.Args.emplace_back();
579
580 if (Expected<StringRef> Key = (*StrTab)[*Arg.KeyIdx])
581 R.Args.back().Key = *Key;
582 else
583 return Key.takeError();
584
585 if (Expected<StringRef> Value = (*StrTab)[*Arg.ValueIdx])
586 R.Args.back().Val = *Value;
587 else
588 return Value.takeError();
589
590 if (Arg.SourceFileNameIdx && Arg.SourceLine && Arg.SourceColumn) {
591 if (Expected<StringRef> SourceFileName =
592 (*StrTab)[*Arg.SourceFileNameIdx]) {
593 R.Args.back().Loc.emplace();
594 R.Args.back().Loc->SourceFilePath = *SourceFileName;
595 R.Args.back().Loc->SourceLine = *Arg.SourceLine;
596 R.Args.back().Loc->SourceColumn = *Arg.SourceColumn;
597 } else
598 return SourceFileName.takeError();
599 }
600 }
601
602 return std::move(Result);
603}
←

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitstream/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_BITSTREAM_BITSTREAMREADER_H
15#define LLVM_BITSTREAM_BITSTREAMREADER_H
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/Bitstream/BitCodes.h"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/Error.h"
22#include "llvm/Support/ErrorHandling.h"
23#include "llvm/Support/MathExtras.h"
24#include "llvm/Support/MemoryBuffer.h"
25#include <algorithm>
26#include <cassert>
27#include <climits>
28#include <cstddef>
29#include <cstdint>
30#include <memory>
31#include <string>
32#include <utility>
33#include <vector>
34
35namespace llvm {
36
37/// This class maintains the abbreviations read from a block info block.
38class BitstreamBlockInfo {
39public:
40 /// This contains information emitted to BLOCKINFO_BLOCK blocks. These
41 /// describe abbreviations that all blocks of the specified ID inherit.
42 struct BlockInfo {
43 unsigned BlockID = 0;
44 std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs;
45 std::string Name;
46 std::vector<std::pair<unsigned, std::string>> RecordNames;
47 };
48
49private:
50 std::vector<BlockInfo> BlockInfoRecords;
51
52public:
53 /// If there is block info for the specified ID, return it, otherwise return
54 /// null.
55 const BlockInfo *getBlockInfo(unsigned BlockID) const {
56 // Common case, the most recent entry matches BlockID.
57 if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
58 return &BlockInfoRecords.back();
59
60 for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
61 i != e; ++i)
62 if (BlockInfoRecords[i].BlockID == BlockID)
63 return &BlockInfoRecords[i];
64 return nullptr;
65 }
66
67 BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
68 if (const BlockInfo *BI = getBlockInfo(BlockID))
69 return *const_cast<BlockInfo*>(BI);
70
71 // Otherwise, add a new record.
72 BlockInfoRecords.emplace_back();
73 BlockInfoRecords.back().BlockID = BlockID;
74 return BlockInfoRecords.back();
75 }
76};
77
78/// This represents a position within a bitstream. There may be multiple
79/// independent cursors reading within one bitstream, each maintaining their
80/// own local state.
81class SimpleBitstreamCursor {
82 ArrayRef<uint8_t> BitcodeBytes;
83 size_t NextChar = 0;
84
85public:
86 /// This is the current data we have pulled from the stream but have not
87 /// returned to the client. This is specifically and intentionally defined to
88 /// follow the word size of the host machine for efficiency. We use word_t in
89 /// places that are aware of this to make it perfectly explicit what is going
90 /// on.
91 using word_t = size_t;
92
93private:
94 word_t CurWord = 0;
95
96 /// This is the number of bits in CurWord that are valid. This is always from
97 /// [0...bits_of(size_t)-1] inclusive.
98 unsigned BitsInCurWord = 0;
99
100public:
101 static const constexpr size_t MaxChunkSize = sizeof(word_t) * 8;
102
103 SimpleBitstreamCursor() = default;
104 explicit SimpleBitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
105 : BitcodeBytes(BitcodeBytes) {}
106 explicit SimpleBitstreamCursor(StringRef BitcodeBytes)
107 : BitcodeBytes(arrayRefFromStringRef(BitcodeBytes)) {}
108 explicit SimpleBitstreamCursor(MemoryBufferRef BitcodeBytes)
109 : SimpleBitstreamCursor(BitcodeBytes.getBuffer()) {}
110
111 bool canSkipToPos(size_t pos) const {
112 // pos can be skipped to if it is a valid address or one byte past the end.
113 return pos <= BitcodeBytes.size();
114 }
115
116 bool AtEndOfStream() {
117 return BitsInCurWord == 0 && BitcodeBytes.size() <= NextChar;
118 }
119
120 /// Return the bit # of the bit we are reading.
121 uint64_t GetCurrentBitNo() const {
122 return NextChar*CHAR_BIT8 - BitsInCurWord;
123 }
124
125 // Return the byte # of the current bit.
126 uint64_t getCurrentByteNo() const { return GetCurrentBitNo() / 8; }
127
128 ArrayRef<uint8_t> getBitcodeBytes() const { return BitcodeBytes; }
129
130 /// Reset the stream to the specified bit number.
131 Error JumpToBit(uint64_t BitNo) {
132 size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
133 unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
134 assert(canSkipToPos(ByteNo) && "Invalid location")((void)0);
135
136 // Move the cursor to the right word.
137 NextChar = ByteNo;
138 BitsInCurWord = 0;
139
140 // Skip over any bits that are already consumed.
141 if (WordBitNo) {
142 if (Expected<word_t> Res = Read(WordBitNo))
143 return Error::success();
144 else
145 return Res.takeError();
146 }
147
148 return Error::success();
149 }
150
151 /// Get a pointer into the bitstream at the specified byte offset.
152 const uint8_t *getPointerToByte(uint64_t ByteNo, uint64_t NumBytes) {
153 return BitcodeBytes.data() + ByteNo;
154 }
155
156 /// Get a pointer into the bitstream at the specified bit offset.
157 ///
158 /// The bit offset must be on a byte boundary.
159 const uint8_t *getPointerToBit(uint64_t BitNo, uint64_t NumBytes) {
160 assert(!(BitNo % 8) && "Expected bit on byte boundary")((void)0);
161 return getPointerToByte(BitNo / 8, NumBytes);
162 }
163
164 Error fillCurWord() {
165 if (NextChar >= BitcodeBytes.size())
166 return createStringError(std::errc::io_error,
167 "Unexpected end of file reading %u of %u bytes",
168 NextChar, BitcodeBytes.size());
169
170 // Read the next word from the stream.
171 const uint8_t *NextCharPtr = BitcodeBytes.data() + NextChar;
172 unsigned BytesRead;
173 if (BitcodeBytes.size() >= NextChar + sizeof(word_t)) {
174 BytesRead = sizeof(word_t);
175 CurWord =
176 support::endian::read<word_t, support::little, support::unaligned>(
177 NextCharPtr);
178 } else {
179 // Short read.
180 BytesRead = BitcodeBytes.size() - NextChar;
181 CurWord = 0;
182 for (unsigned B = 0; B != BytesRead; ++B)
183 CurWord |= uint64_t(NextCharPtr[B]) << (B * 8);
184 }
185 NextChar += BytesRead;
186 BitsInCurWord = BytesRead * 8;
187 return Error::success();
188 }
189
190 Expected<word_t> Read(unsigned NumBits) {
191 static const unsigned BitsInWord = MaxChunkSize;
192
193 assert(NumBits && NumBits <= BitsInWord &&((void)0)
194 "Cannot return zero or more than BitsInWord bits!")((void)0);
195
196 static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
12
←
'?' condition is true
→
197
198 // If the field is fully contained by CurWord, return it quickly.
199 if (BitsInCurWord >= NumBits) {
13
←
Assuming 'NumBits' is <= field 'BitsInCurWord'
→
14
←
Taking true branch
→
200 word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));
15
←
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'
201
202 // Use a mask to avoid undefined behavior.
203 CurWord >>= (NumBits & Mask);
204
205 BitsInCurWord -= NumBits;
206 return R;
207 }
208
209 word_t R = BitsInCurWord ? CurWord : 0;
210 unsigned BitsLeft = NumBits - BitsInCurWord;
211
212 if (Error fillResult = fillCurWord())
213 return std::move(fillResult);
214
215 // If we run out of data, abort.
216 if (BitsLeft > BitsInCurWord)
217 return createStringError(std::errc::io_error,
218 "Unexpected end of file reading %u of %u bits",
219 BitsInCurWord, BitsLeft);
220
221 word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
222
223 // Use a mask to avoid undefined behavior.
224 CurWord >>= (BitsLeft & Mask);
225
226 BitsInCurWord -= BitsLeft;
227
228 R |= R2 << (NumBits - BitsLeft);
229
230 return R;
231 }
232
233 Expected<uint32_t> ReadVBR(unsigned NumBits) {
234 Expected<unsigned> MaybeRead = Read(NumBits);
235 if (!MaybeRead)
236 return MaybeRead;
237 uint32_t Piece = MaybeRead.get();
238
239 if ((Piece & (1U << (NumBits-1))) == 0)
240 return Piece;
241
242 uint32_t Result = 0;
243 unsigned NextBit = 0;
244 while (true) {
245 Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;
246
247 if ((Piece & (1U << (NumBits-1))) == 0)
248 return Result;
249
250 NextBit += NumBits-1;
251 MaybeRead = Read(NumBits);
252 if (!MaybeRead)
253 return MaybeRead;
254 Piece = MaybeRead.get();
255 }
256 }
257
258 // Read a VBR that may have a value up to 64-bits in size. The chunk size of
259 // the VBR must still be <= 32 bits though.
260 Expected<uint64_t> ReadVBR64(unsigned NumBits) {
261 Expected<uint64_t> MaybeRead = Read(NumBits);
262 if (!MaybeRead)
263 return MaybeRead;
264 uint32_t Piece = MaybeRead.get();
265
266 if ((Piece & (1U << (NumBits-1))) == 0)
267 return uint64_t(Piece);
268
269 uint64_t Result = 0;
270 unsigned NextBit = 0;
271 while (true) {
272 Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
273
274 if ((Piece & (1U << (NumBits-1))) == 0)
275 return Result;
276
277 NextBit += NumBits-1;
278 MaybeRead = Read(NumBits);
279 if (!MaybeRead)
280 return MaybeRead;
281 Piece = MaybeRead.get();
282 }
283 }
284
285 void SkipToFourByteBoundary() {
286 // If word_t is 64-bits and if we've read less than 32 bits, just dump
287 // the bits we have up to the next 32-bit boundary.
288 if (sizeof(word_t) > 4 &&
289 BitsInCurWord >= 32) {
290 CurWord >>= BitsInCurWord-32;
291 BitsInCurWord = 32;
292 return;
293 }
294
295 BitsInCurWord = 0;
296 }
297
298 /// Return the size of the stream in bytes.
299 size_t SizeInBytes() const { return BitcodeBytes.size(); }
300
301 /// Skip to the end of the file.
302 void skipToEnd() { NextChar = BitcodeBytes.size(); }
303};
304
305/// When advancing through a bitstream cursor, each advance can discover a few
306/// different kinds of entries:
307struct BitstreamEntry {
308 enum {
309 Error, // Malformed bitcode was found.
310 EndBlock, // We've reached the end of the current block, (or the end of the
311 // file, which is treated like a series of EndBlock records.
312 SubBlock, // This is the start of a new subblock of a specific ID.
313 Record // This is a record with a specific AbbrevID.
314 } Kind;
315
316 unsigned ID;
317
318 static BitstreamEntry getError() {
319 BitstreamEntry E; E.Kind = Error; return E;
320 }
321
322 static BitstreamEntry getEndBlock() {
323 BitstreamEntry E; E.Kind = EndBlock; return E;
324 }
325
326 static BitstreamEntry getSubBlock(unsigned ID) {
327 BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
328 }
329
330 static BitstreamEntry getRecord(unsigned AbbrevID) {
331 BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
332 }
333};
334
335/// This represents a position within a bitcode file, implemented on top of a
336/// SimpleBitstreamCursor.
337///
338/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
339/// be passed by value.
340class BitstreamCursor : SimpleBitstreamCursor {
341 // This is the declared size of code values used for the current block, in
342 // bits.
343 unsigned CurCodeSize = 2;
344
345 /// Abbrevs installed at in this block.
346 std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;
347
348 struct Block {
349 unsigned PrevCodeSize;
350 std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;
351
352 explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
353 };
354
355 /// This tracks the codesize of parent blocks.
356 SmallVector<Block, 8> BlockScope;
357
358 BitstreamBlockInfo *BlockInfo = nullptr;
359
360public:
361 static const size_t MaxChunkSize = sizeof(word_t) * 8;
362
363 BitstreamCursor() = default;
364 explicit BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
365 : SimpleBitstreamCursor(BitcodeBytes) {}
366 explicit BitstreamCursor(StringRef BitcodeBytes)
367 : SimpleBitstreamCursor(BitcodeBytes) {}
368 explicit BitstreamCursor(MemoryBufferRef BitcodeBytes)
369 : SimpleBitstreamCursor(BitcodeBytes) {}
370
371 using SimpleBitstreamCursor::AtEndOfStream;
372 using SimpleBitstreamCursor::canSkipToPos;
373 using SimpleBitstreamCursor::fillCurWord;
374 using SimpleBitstreamCursor::getBitcodeBytes;
375 using SimpleBitstreamCursor::GetCurrentBitNo;
376 using SimpleBitstreamCursor::getCurrentByteNo;
377 using SimpleBitstreamCursor::getPointerToByte;
378 using SimpleBitstreamCursor::JumpToBit;
379 using SimpleBitstreamCursor::Read;
380 using SimpleBitstreamCursor::ReadVBR;
381 using SimpleBitstreamCursor::ReadVBR64;
382 using SimpleBitstreamCursor::SizeInBytes;
383 using SimpleBitstreamCursor::skipToEnd;
384
385 /// Return the number of bits used to encode an abbrev #.
386 unsigned getAbbrevIDWidth() const { return CurCodeSize; }
387
388 /// Flags that modify the behavior of advance().
389 enum {
390 /// If this flag is used, the advance() method does not automatically pop
391 /// the block scope when the end of a block is reached.
392 AF_DontPopBlockAtEnd = 1,
393
394 /// If this flag is used, abbrev entries are returned just like normal
395 /// records.
396 AF_DontAutoprocessAbbrevs = 2
397 };
398
399 /// Advance the current bitstream, returning the next entry in the stream.
400 Expected<BitstreamEntry> advance(unsigned Flags = 0) {
401 while (true) {
8
←
Loop condition is true. Entering loop body
→
402 if (AtEndOfStream())
9
←
Taking false branch
→
403 return BitstreamEntry::getError();
404
405 Expected<unsigned> MaybeCode = ReadCode();
10
←
Calling 'BitstreamCursor::ReadCode'
→
406 if (!MaybeCode)
407 return MaybeCode.takeError();
408 unsigned Code = MaybeCode.get();
409
410 if (Code == bitc::END_BLOCK) {
411 // Pop the end of the block unless Flags tells us not to.
412 if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
413 return BitstreamEntry::getError();
414 return BitstreamEntry::getEndBlock();
415 }
416
417 if (Code == bitc::ENTER_SUBBLOCK) {
418 if (Expected<unsigned> MaybeSubBlock = ReadSubBlockID())
419 return BitstreamEntry::getSubBlock(MaybeSubBlock.get());
420 else
421 return MaybeSubBlock.takeError();
422 }
423
424 if (Code == bitc::DEFINE_ABBREV &&
425 !(Flags & AF_DontAutoprocessAbbrevs)) {
426 // We read and accumulate abbrev's, the client can't do anything with
427 // them anyway.
428 if (Error Err = ReadAbbrevRecord())
429 return std::move(Err);
430 continue;
431 }
432
433 return BitstreamEntry::getRecord(Code);
434 }
435 }
436
437 /// This is a convenience function for clients that don't expect any
438 /// subblocks. This just skips over them automatically.
439 Expected<BitstreamEntry> advanceSkippingSubblocks(unsigned Flags = 0) {
440 while (true) {
441 // If we found a normal entry, return it.
442 Expected<BitstreamEntry> MaybeEntry = advance(Flags);
443 if (!MaybeEntry)
444 return MaybeEntry;
445 BitstreamEntry Entry = MaybeEntry.get();
446
447 if (Entry.Kind != BitstreamEntry::SubBlock)
448 return Entry;
449
450 // If we found a sub-block, just skip over it and check the next entry.
451 if (Error Err = SkipBlock())
452 return std::move(Err);
453 }
454 }
455
456 Expected<unsigned> ReadCode() { return Read(CurCodeSize); }
11
←
Calling 'SimpleBitstreamCursor::Read'
→
457
458 // Block header:
459 // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
460
461 /// Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
462 Expected<unsigned> ReadSubBlockID() { return ReadVBR(bitc::BlockIDWidth); }
463
464 /// Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body
465 /// of this block.
466 Error SkipBlock() {
467 // Read and ignore the codelen value.
468 if (Expected<uint32_t> Res = ReadVBR(bitc::CodeLenWidth))
469 ; // Since we are skipping this block, we don't care what code widths are
470 // used inside of it.
471 else
472 return Res.takeError();
473
474 SkipToFourByteBoundary();
475 Expected<unsigned> MaybeNum = Read(bitc::BlockSizeWidth);
476 if (!MaybeNum)
477 return MaybeNum.takeError();
478 size_t NumFourBytes = MaybeNum.get();
479
480 // Check that the block wasn't partially defined, and that the offset isn't
481 // bogus.
482 size_t SkipTo = GetCurrentBitNo() + NumFourBytes * 4 * 8;
483 if (AtEndOfStream())
484 return createStringError(std::errc::illegal_byte_sequence,
485 "can't skip block: already at end of stream");
486 if (!canSkipToPos(SkipTo / 8))
487 return createStringError(std::errc::illegal_byte_sequence,
488 "can't skip to bit %zu from %" PRIu64"llu", SkipTo,
489 GetCurrentBitNo());
490
491 if (Error Res = JumpToBit(SkipTo))
492 return Res;
493
494 return Error::success();
495 }
496
497 /// Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
498 Error EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
499
500 bool ReadBlockEnd() {
501 if (BlockScope.empty()) return true;
502
503 // Block tail:
504 // [END_BLOCK, <align4bytes>]
505 SkipToFourByteBoundary();
506
507 popBlockScope();
508 return false;
509 }
510
511private:
512 void popBlockScope() {
513 CurCodeSize = BlockScope.back().PrevCodeSize;
514
515 CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
516 BlockScope.pop_back();
517 }
518
519 //===--------------------------------------------------------------------===//
520 // Record Processing
521 //===--------------------------------------------------------------------===//
522
523public:
524 /// Return the abbreviation for the specified AbbrevId.
525 const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
526 unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
527 if (AbbrevNo >= CurAbbrevs.size())
528 report_fatal_error("Invalid abbrev number");
529 return CurAbbrevs[AbbrevNo].get();
530 }
531
532 /// Read the current record and discard it, returning the code for the record.
533 Expected<unsigned> skipRecord(unsigned AbbrevID);
534
535 Expected<unsigned> readRecord(unsigned AbbrevID,
536 SmallVectorImpl<uint64_t> &Vals,
537 StringRef *Blob = nullptr);
538
539 //===--------------------------------------------------------------------===//
540 // Abbrev Processing
541 //===--------------------------------------------------------------------===//
542 Error ReadAbbrevRecord();
543
544 /// Read and return a block info block from the bitstream. If an error was
545 /// encountered, return None.
546 ///
547 /// \param ReadBlockInfoNames Whether to read block/record name information in
548 /// the BlockInfo block. Only llvm-bcanalyzer uses this.
549 Expected<Optional<BitstreamBlockInfo>>
550 ReadBlockInfoBlock(bool ReadBlockInfoNames = false);
551
552 /// Set the block info to be used by this BitstreamCursor to interpret
553 /// abbreviated records.
554 void setBlockInfo(BitstreamBlockInfo *BI) { BlockInfo = BI; }
555};
556
557} // end llvm namespace
558
559#endif // LLVM_BITSTREAM_BITSTREAMREADER_H