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/Remarks/BitstreamRemarkContainer.h"
17 #include "llvm/Support/MemoryBuffer.h"
18 
19 using namespace llvm;
20 using namespace llvm::remarks;
21 
22 static 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 
29 static 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 
36 BitstreamMetaParserHelper::BitstreamMetaParserHelper(
37     BitstreamCursor &Stream, BitstreamBlockInfo &BlockInfo)
38     : Stream(Stream), BlockInfo(BlockInfo) {}
39 
40 /// Parse a record and fill in the fields in the parser.
41 static 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 
83 BitstreamRemarkParserHelper::BitstreamRemarkParserHelper(
84     BitstreamCursor &Stream)
85     : Stream(Stream) {}
86 
87 /// Parse a record and fill in the fields in the parser.
88 static 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 
156 template <typename T>
157 static Error parseBlock(T &ParserHelper, unsigned BlockID,
158                         const char *BlockName) {
159   BitstreamCursor &Stream = ParserHelper.Stream;
160   Expected<BitstreamEntry> Next = Stream.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     Expected<BitstreamEntry> 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 
200 Error BitstreamMetaParserHelper::parse() {
201   return parseBlock(*this, META_BLOCK_ID, "META_BLOCK");
202 }
203 
204 Error BitstreamRemarkParserHelper::parse() {
205   return parseBlock(*this, REMARK_BLOCK_ID, "REMARK_BLOCK");
206 }
207 
208 BitstreamParserHelper::BitstreamParserHelper(StringRef Buffer)
209     : Stream(Buffer) {}
210 
211 Expected<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 
221 Error 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 
248 static 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 
272 Expected<bool> BitstreamParserHelper::isMetaBlock() {
273   return isBlock(Stream, META_BLOCK_ID);
274 }
275 
276 Expected<bool> BitstreamParserHelper::isRemarkBlock() {
277   return isBlock(Stream, META_BLOCK_ID);
278 }
279 
280 static Error validateMagicNumber(StringRef Magic) {
281   if (Magic != 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(), Magic.data());
285   return Error::success();
286 }
287 
288 static Error advanceToMetaBlock(BitstreamParserHelper &Helper) {
289   Expected<std::array<char, 4>> Magic = Helper.parseMagic();
290   if (!Magic)
291     return Magic.takeError();
292   if (Error E = validateMagicNumber(StringRef(Magic->data(), Magic->size())))
293     return E;
294   if (Error E = Helper.parseBlockInfoBlock())
295     return E;
296   Expected<bool> isMetaBlock = Helper.isMetaBlock();
297   if (!isMetaBlock)
298     return isMetaBlock.takeError();
299   if (!*isMetaBlock)
300     return createStringError(
301         std::make_error_code(std::errc::illegal_byte_sequence),
302         "Expecting META_BLOCK after the BLOCKINFO_BLOCK.");
303   return Error::success();
304 }
305 
306 Expected<std::unique_ptr<BitstreamRemarkParser>>
307 remarks::createBitstreamParserFromMeta(StringRef Buf,
308                                        Optional<ParsedStringTable> StrTab) {
309   BitstreamParserHelper Helper(Buf);
310   Expected<std::array<char, 4>> Magic = Helper.parseMagic();
311   if (!Magic)
312     return Magic.takeError();
313 
314   if (Error E = validateMagicNumber(StringRef(Magic->data(), Magic->size())))
315     return std::move(E);
316 
317   return StrTab
318              ? std::make_unique<BitstreamRemarkParser>(Buf, std::move(*StrTab))
319              : std::make_unique<BitstreamRemarkParser>(Buf);
320 }
321 
322 Expected<std::unique_ptr<Remark>> BitstreamRemarkParser::next() {
323   if (ParserHelper.atEndOfStream())
324     return make_error<EndOfFileError>();
325 
326   if (!ReadyToParseRemarks) {
327     if (Error E = parseMeta())
328       return std::move(E);
329     ReadyToParseRemarks = true;
330   }
331 
332   return parseRemark();
333 }
334 
335 Error BitstreamRemarkParser::parseMeta() {
336   // Advance and to the meta block.
337   if (Error E = advanceToMetaBlock(ParserHelper))
338     return E;
339 
340   BitstreamMetaParserHelper MetaHelper(ParserHelper.Stream,
341                                        ParserHelper.BlockInfo);
342   if (Error E = MetaHelper.parse())
343     return E;
344 
345   if (Error E = processCommonMeta(MetaHelper))
346     return E;
347 
348   switch (ContainerType) {
349   case BitstreamRemarkContainerType::Standalone:
350     return processStandaloneMeta(MetaHelper);
351   case BitstreamRemarkContainerType::SeparateRemarksFile:
352     return processSeparateRemarksFileMeta(MetaHelper);
353   case BitstreamRemarkContainerType::SeparateRemarksMeta:
354     return processSeparateRemarksMetaMeta(MetaHelper);
355   }
356 }
357 
358 Error BitstreamRemarkParser::processCommonMeta(
359     BitstreamMetaParserHelper &MetaHelper) {
360   if (Optional<uint64_t> Version = MetaHelper.ContainerVersion)
361     ContainerVersion = *Version;
362   else
363     return createStringError(
364         std::make_error_code(std::errc::illegal_byte_sequence),
365         "Error while parsing BLOCK_META: missing container version.");
366 
367   if (Optional<uint8_t> Type = MetaHelper.ContainerType) {
368     // Always >= BitstreamRemarkContainerType::First since it's unsigned.
369     if (*Type > static_cast<uint8_t>(BitstreamRemarkContainerType::Last))
370       return createStringError(
371           std::make_error_code(std::errc::illegal_byte_sequence),
372           "Error while parsing BLOCK_META: invalid container type.");
373 
374     ContainerType = static_cast<BitstreamRemarkContainerType>(*Type);
375   } else
376     return createStringError(
377         std::make_error_code(std::errc::illegal_byte_sequence),
378         "Error while parsing BLOCK_META: missing container type.");
379 
380   return Error::success();
381 }
382 
383 static Error processStrTab(BitstreamRemarkParser &P,
384                            Optional<StringRef> StrTabBuf) {
385   if (!StrTabBuf)
386     return createStringError(
387         std::make_error_code(std::errc::illegal_byte_sequence),
388         "Error while parsing BLOCK_META: missing string table.");
389   // Parse and assign the string table.
390   P.StrTab.emplace(*StrTabBuf);
391   return Error::success();
392 }
393 
394 static Error processRemarkVersion(BitstreamRemarkParser &P,
395                                   Optional<uint64_t> RemarkVersion) {
396   if (!RemarkVersion)
397     return createStringError(
398         std::make_error_code(std::errc::illegal_byte_sequence),
399         "Error while parsing BLOCK_META: missing remark version.");
400   P.RemarkVersion = *RemarkVersion;
401   return Error::success();
402 }
403 
404 Error BitstreamRemarkParser::processExternalFilePath(
405     Optional<StringRef> ExternalFilePath) {
406   if (!ExternalFilePath)
407     return createStringError(
408         std::make_error_code(std::errc::illegal_byte_sequence),
409         "Error while parsing BLOCK_META: missing external file path.");
410 
411   // External file: open the external file, parse it, check if its metadata
412   // matches the one from the separate metadata, then replace the current parser
413   // with the one parsing the remarks.
414   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
415       MemoryBuffer::getFile(*ExternalFilePath);
416   if (std::error_code EC = BufferOrErr.getError())
417     return errorCodeToError(EC);
418   TmpRemarkBuffer = std::move(*BufferOrErr);
419 
420   // Create a separate parser used for parsing the separate file.
421   ParserHelper = BitstreamParserHelper(TmpRemarkBuffer->getBuffer());
422   // Advance and check until we can parse the meta block.
423   if (Error E = advanceToMetaBlock(ParserHelper))
424     return E;
425   // Parse the meta from the separate file.
426   // Note: here we overwrite the BlockInfo with the one from the file. This will
427   // be used to parse the rest of the file.
428   BitstreamMetaParserHelper SeparateMetaHelper(ParserHelper.Stream,
429                                                ParserHelper.BlockInfo);
430   if (Error E = SeparateMetaHelper.parse())
431     return E;
432 
433   uint64_t PreviousContainerVersion = ContainerVersion;
434   if (Error E = processCommonMeta(SeparateMetaHelper))
435     return E;
436 
437   if (ContainerType != BitstreamRemarkContainerType::SeparateRemarksFile)
438     return createStringError(
439         std::make_error_code(std::errc::illegal_byte_sequence),
440         "Error while parsing external file's BLOCK_META: wrong container "
441         "type.");
442 
443   if (PreviousContainerVersion != ContainerVersion)
444     return createStringError(
445         std::make_error_code(std::errc::illegal_byte_sequence),
446         "Error while parsing external file's BLOCK_META: mismatching versions: "
447         "original meta: %lu, external file meta: %lu.",
448         PreviousContainerVersion, ContainerVersion);
449 
450   // Process the meta from the separate file.
451   return processSeparateRemarksFileMeta(SeparateMetaHelper);
452 }
453 
454 Error BitstreamRemarkParser::processStandaloneMeta(
455     BitstreamMetaParserHelper &Helper) {
456   if (Error E = processStrTab(*this, Helper.StrTabBuf))
457     return E;
458   return processRemarkVersion(*this, Helper.RemarkVersion);
459 }
460 
461 Error BitstreamRemarkParser::processSeparateRemarksFileMeta(
462     BitstreamMetaParserHelper &Helper) {
463   return processRemarkVersion(*this, Helper.RemarkVersion);
464 }
465 
466 Error BitstreamRemarkParser::processSeparateRemarksMetaMeta(
467     BitstreamMetaParserHelper &Helper) {
468   if (Error E = processStrTab(*this, Helper.StrTabBuf))
469     return E;
470   return processExternalFilePath(Helper.ExternalFilePath);
471 }
472 
473 Expected<std::unique_ptr<Remark>> BitstreamRemarkParser::parseRemark() {
474   BitstreamRemarkParserHelper RemarkHelper(ParserHelper.Stream);
475   if (Error E = RemarkHelper.parse())
476     return std::move(E);
477 
478   return processRemark(RemarkHelper);
479 }
480 
481 Expected<std::unique_ptr<Remark>>
482 BitstreamRemarkParser::processRemark(BitstreamRemarkParserHelper &Helper) {
483   std::unique_ptr<Remark> Result = std::make_unique<Remark>();
484   Remark &R = *Result;
485 
486   if (StrTab == None)
487     return createStringError(
488         std::make_error_code(std::errc::invalid_argument),
489         "Error while parsing BLOCK_REMARK: missing string table.");
490 
491   if (!Helper.Type)
492     return createStringError(
493         std::make_error_code(std::errc::illegal_byte_sequence),
494         "Error while parsing BLOCK_REMARK: missing remark type.");
495 
496   // Always >= Type::First since it's unsigned.
497   if (*Helper.Type > static_cast<uint8_t>(Type::Last))
498     return createStringError(
499         std::make_error_code(std::errc::illegal_byte_sequence),
500         "Error while parsing BLOCK_REMARK: unknown remark type.");
501 
502   R.RemarkType = static_cast<Type>(*Helper.Type);
503 
504   if (!Helper.RemarkNameIdx)
505     return createStringError(
506         std::make_error_code(std::errc::illegal_byte_sequence),
507         "Error while parsing BLOCK_REMARK: missing remark name.");
508 
509   if (Expected<StringRef> RemarkName = (*StrTab)[*Helper.RemarkNameIdx])
510     R.RemarkName = *RemarkName;
511   else
512     return RemarkName.takeError();
513 
514   if (!Helper.PassNameIdx)
515     return createStringError(
516         std::make_error_code(std::errc::illegal_byte_sequence),
517         "Error while parsing BLOCK_REMARK: missing remark pass.");
518 
519   if (Expected<StringRef> PassName = (*StrTab)[*Helper.PassNameIdx])
520     R.PassName = *PassName;
521   else
522     return PassName.takeError();
523 
524   if (!Helper.FunctionNameIdx)
525     return createStringError(
526         std::make_error_code(std::errc::illegal_byte_sequence),
527         "Error while parsing BLOCK_REMARK: missing remark function name.");
528   if (Expected<StringRef> FunctionName = (*StrTab)[*Helper.FunctionNameIdx])
529     R.FunctionName = *FunctionName;
530   else
531     return FunctionName.takeError();
532 
533   if (Helper.SourceFileNameIdx && Helper.SourceLine && Helper.SourceColumn) {
534     Expected<StringRef> SourceFileName = (*StrTab)[*Helper.SourceFileNameIdx];
535     if (!SourceFileName)
536       return SourceFileName.takeError();
537     R.Loc.emplace();
538     R.Loc->SourceFilePath = *SourceFileName;
539     R.Loc->SourceLine = *Helper.SourceLine;
540     R.Loc->SourceColumn = *Helper.SourceColumn;
541   }
542 
543   if (Helper.Hotness)
544     R.Hotness = *Helper.Hotness;
545 
546   if (!Helper.Args)
547     return std::move(Result);
548 
549   for (const BitstreamRemarkParserHelper::Argument &Arg : *Helper.Args) {
550     if (!Arg.KeyIdx)
551       return createStringError(
552           std::make_error_code(std::errc::illegal_byte_sequence),
553           "Error while parsing BLOCK_REMARK: missing key in remark argument.");
554     if (!Arg.ValueIdx)
555       return createStringError(
556           std::make_error_code(std::errc::illegal_byte_sequence),
557           "Error while parsing BLOCK_REMARK: missing value in remark "
558           "argument.");
559 
560     // We have at least a key and a value, create an entry.
561     R.Args.emplace_back();
562 
563     if (Expected<StringRef> Key = (*StrTab)[*Arg.KeyIdx])
564       R.Args.back().Key = *Key;
565     else
566       return Key.takeError();
567 
568     if (Expected<StringRef> Value = (*StrTab)[*Arg.ValueIdx])
569       R.Args.back().Val = *Value;
570     else
571       return Value.takeError();
572 
573     if (Arg.SourceFileNameIdx && Arg.SourceLine && Arg.SourceColumn) {
574       if (Expected<StringRef> SourceFileName =
575               (*StrTab)[*Arg.SourceFileNameIdx]) {
576         R.Args.back().Loc.emplace();
577         R.Args.back().Loc->SourceFilePath = *SourceFileName;
578         R.Args.back().Loc->SourceLine = *Arg.SourceLine;
579         R.Args.back().Loc->SourceColumn = *Arg.SourceColumn;
580       } else
581         return SourceFileName.takeError();
582     }
583   }
584 
585   return std::move(Result);
586 }
587