diff options
Diffstat (limited to 'gnu/llvm/lib/XRay/Trace.cpp')
| -rw-r--r-- | gnu/llvm/lib/XRay/Trace.cpp | 403 |
1 files changed, 383 insertions, 20 deletions
diff --git a/gnu/llvm/lib/XRay/Trace.cpp b/gnu/llvm/lib/XRay/Trace.cpp index 51000c777de..6677063f944 100644 --- a/gnu/llvm/lib/XRay/Trace.cpp +++ b/gnu/llvm/lib/XRay/Trace.cpp @@ -24,8 +24,8 @@ using llvm::yaml::Input; using XRayRecordStorage = std::aligned_storage<sizeof(XRayRecord), alignof(XRayRecord)>::type; -Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader, - std::vector<XRayRecord> &Records) { +// Populates the FileHeader reference by reading the first 32 bytes of the file. +Error readBinaryFormatHeader(StringRef Data, XRayFileHeader &FileHeader) { // FIXME: Maybe deduce whether the data is little or big-endian using some // magic bytes in the beginning of the file? @@ -37,16 +37,6 @@ Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader, // (4) uint32 : bitfield // (8) uint64 : cycle frequency // (16) - : padding - // - if (Data.size() < 32) - return make_error<StringError>( - "Not enough bytes for an XRay log.", - std::make_error_code(std::errc::invalid_argument)); - - if (Data.size() - 32 == 0 || Data.size() % 32 != 0) - return make_error<StringError>( - "Invalid-sized XRay data.", - std::make_error_code(std::errc::invalid_argument)); DataExtractor HeaderExtractor(Data, true, 8); uint32_t OffsetPtr = 0; @@ -56,11 +46,29 @@ Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader, FileHeader.ConstantTSC = Bitfield & 1uL; FileHeader.NonstopTSC = Bitfield & 1uL << 1; FileHeader.CycleFrequency = HeaderExtractor.getU64(&OffsetPtr); - + std::memcpy(&FileHeader.FreeFormData, Data.bytes_begin() + OffsetPtr, 16); if (FileHeader.Version != 1) return make_error<StringError>( Twine("Unsupported XRay file version: ") + Twine(FileHeader.Version), std::make_error_code(std::errc::invalid_argument)); + return Error::success(); +} + +Error loadNaiveFormatLog(StringRef Data, XRayFileHeader &FileHeader, + std::vector<XRayRecord> &Records) { + // Check that there is at least a header + if (Data.size() < 32) + return make_error<StringError>( + "Not enough bytes for an XRay log.", + std::make_error_code(std::errc::invalid_argument)); + + if (Data.size() - 32 == 0 || Data.size() % 32 != 0) + return make_error<StringError>( + "Invalid-sized XRay data.", + std::make_error_code(std::errc::invalid_argument)); + + if (auto E = readBinaryFormatHeader(Data, FileHeader)) + return E; // Each record after the header will be 32 bytes, in the following format: // @@ -98,9 +106,357 @@ Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader, return Error::success(); } -Error YAMLLogLoader(StringRef Data, XRayFileHeader &FileHeader, - std::vector<XRayRecord> &Records) { +/// When reading from a Flight Data Recorder mode log, metadata records are +/// sparse compared to packed function records, so we must maintain state as we +/// read through the sequence of entries. This allows the reader to denormalize +/// the CPUId and Thread Id onto each Function Record and transform delta +/// encoded TSC values into absolute encodings on each record. +struct FDRState { + uint16_t CPUId; + uint16_t ThreadId; + uint64_t BaseTSC; + + /// Encode some of the state transitions for the FDR log reader as explicit + /// checks. These are expectations for the next Record in the stream. + enum class Token { + NEW_BUFFER_RECORD_OR_EOF, + WALLCLOCK_RECORD, + NEW_CPU_ID_RECORD, + FUNCTION_SEQUENCE, + SCAN_TO_END_OF_THREAD_BUF, + CUSTOM_EVENT_DATA, + }; + Token Expects; + + // Each threads buffer may have trailing garbage to scan over, so we track our + // progress. + uint64_t CurrentBufferSize; + uint64_t CurrentBufferConsumed; +}; + +Twine fdrStateToTwine(const FDRState::Token &state) { + switch (state) { + case FDRState::Token::NEW_BUFFER_RECORD_OR_EOF: + return "NEW_BUFFER_RECORD_OR_EOF"; + case FDRState::Token::WALLCLOCK_RECORD: + return "WALLCLOCK_RECORD"; + case FDRState::Token::NEW_CPU_ID_RECORD: + return "NEW_CPU_ID_RECORD"; + case FDRState::Token::FUNCTION_SEQUENCE: + return "FUNCTION_SEQUENCE"; + case FDRState::Token::SCAN_TO_END_OF_THREAD_BUF: + return "SCAN_TO_END_OF_THREAD_BUF"; + case FDRState::Token::CUSTOM_EVENT_DATA: + return "CUSTOM_EVENT_DATA"; + } + return "UNKNOWN"; +} + +/// State transition when a NewBufferRecord is encountered. +Error processFDRNewBufferRecord(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor) { + + if (State.Expects != FDRState::Token::NEW_BUFFER_RECORD_OR_EOF) + return make_error<StringError>( + "Malformed log. Read New Buffer record kind out of sequence", + std::make_error_code(std::errc::executable_format_error)); + uint32_t OffsetPtr = 1; // 1 byte into record. + State.ThreadId = RecordExtractor.getU16(&OffsetPtr); + State.Expects = FDRState::Token::WALLCLOCK_RECORD; + return Error::success(); +} + +/// State transition when an EndOfBufferRecord is encountered. +Error processFDREndOfBufferRecord(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor) { + if (State.Expects == FDRState::Token::NEW_BUFFER_RECORD_OR_EOF) + return make_error<StringError>( + "Malformed log. Received EOB message without current buffer.", + std::make_error_code(std::errc::executable_format_error)); + State.Expects = FDRState::Token::SCAN_TO_END_OF_THREAD_BUF; + return Error::success(); +} + +/// State transition when a NewCPUIdRecord is encountered. +Error processFDRNewCPUIdRecord(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor) { + if (State.Expects != FDRState::Token::FUNCTION_SEQUENCE && + State.Expects != FDRState::Token::NEW_CPU_ID_RECORD) + return make_error<StringError>( + "Malformed log. Read NewCPUId record kind out of sequence", + std::make_error_code(std::errc::executable_format_error)); + uint32_t OffsetPtr = 1; // Read starting after the first byte. + State.CPUId = RecordExtractor.getU16(&OffsetPtr); + State.BaseTSC = RecordExtractor.getU64(&OffsetPtr); + State.Expects = FDRState::Token::FUNCTION_SEQUENCE; + return Error::success(); +} + +/// State transition when a TSCWrapRecord (overflow detection) is encountered. +Error processFDRTSCWrapRecord(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor) { + if (State.Expects != FDRState::Token::FUNCTION_SEQUENCE) + return make_error<StringError>( + "Malformed log. Read TSCWrap record kind out of sequence", + std::make_error_code(std::errc::executable_format_error)); + uint32_t OffsetPtr = 1; // Read starting after the first byte. + State.BaseTSC = RecordExtractor.getU64(&OffsetPtr); + return Error::success(); +} + +/// State transition when a WallTimeMarkerRecord is encountered. +Error processFDRWallTimeRecord(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor) { + if (State.Expects != FDRState::Token::WALLCLOCK_RECORD) + return make_error<StringError>( + "Malformed log. Read Wallclock record kind out of sequence", + std::make_error_code(std::errc::executable_format_error)); + // We don't encode the wall time into any of the records. + // XRayRecords are concerned with the TSC instead. + State.Expects = FDRState::Token::NEW_CPU_ID_RECORD; + return Error::success(); +} + +/// State transition when a CustomEventMarker is encountered. +Error processCustomEventMarker(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor, + size_t &RecordSize) { + // We can encounter a CustomEventMarker anywhere in the log, so we can handle + // it regardless of the expectation. However, we do se the expectation to read + // a set number of fixed bytes, as described in the metadata. + uint32_t OffsetPtr = 1; // Read after the first byte. + uint32_t DataSize = RecordExtractor.getU32(&OffsetPtr); + uint64_t TSC = RecordExtractor.getU64(&OffsetPtr); + + // FIXME: Actually represent the record through the API. For now we only skip + // through the data. + (void)TSC; + RecordSize = 16 + DataSize; + return Error::success(); +} + +/// Advances the state machine for reading the FDR record type by reading one +/// Metadata Record and updating the State appropriately based on the kind of +/// record encountered. The RecordKind is encoded in the first byte of the +/// Record, which the caller should pass in because they have already read it +/// to determine that this is a metadata record as opposed to a function record. +Error processFDRMetadataRecord(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor, + size_t &RecordSize) { + // The remaining 7 bits are the RecordKind enum. + uint8_t RecordKind = RecordFirstByte >> 1; + switch (RecordKind) { + case 0: // NewBuffer + if (auto E = + processFDRNewBufferRecord(State, RecordFirstByte, RecordExtractor)) + return E; + break; + case 1: // EndOfBuffer + if (auto E = processFDREndOfBufferRecord(State, RecordFirstByte, + RecordExtractor)) + return E; + break; + case 2: // NewCPUId + if (auto E = + processFDRNewCPUIdRecord(State, RecordFirstByte, RecordExtractor)) + return E; + break; + case 3: // TSCWrap + if (auto E = + processFDRTSCWrapRecord(State, RecordFirstByte, RecordExtractor)) + return E; + break; + case 4: // WallTimeMarker + if (auto E = + processFDRWallTimeRecord(State, RecordFirstByte, RecordExtractor)) + return E; + break; + case 5: // CustomEventMarker + if (auto E = processCustomEventMarker(State, RecordFirstByte, + RecordExtractor, RecordSize)) + return E; + break; + default: + // Widen the record type to uint16_t to prevent conversion to char. + return make_error<StringError>( + Twine("Illegal metadata record type: ") + .concat(Twine(static_cast<unsigned>(RecordKind))), + std::make_error_code(std::errc::executable_format_error)); + } + return Error::success(); +} + +/// Reads a function record from an FDR format log, appending a new XRayRecord +/// to the vector being populated and updating the State with a new value +/// reference value to interpret TSC deltas. +/// +/// The XRayRecord constructed includes information from the function record +/// processed here as well as Thread ID and CPU ID formerly extracted into +/// State. +Error processFDRFunctionRecord(FDRState &State, uint8_t RecordFirstByte, + DataExtractor &RecordExtractor, + std::vector<XRayRecord> &Records) { + switch (State.Expects) { + case FDRState::Token::NEW_BUFFER_RECORD_OR_EOF: + return make_error<StringError>( + "Malformed log. Received Function Record before new buffer setup.", + std::make_error_code(std::errc::executable_format_error)); + case FDRState::Token::WALLCLOCK_RECORD: + return make_error<StringError>( + "Malformed log. Received Function Record when expecting wallclock.", + std::make_error_code(std::errc::executable_format_error)); + case FDRState::Token::NEW_CPU_ID_RECORD: + return make_error<StringError>( + "Malformed log. Received Function Record before first CPU record.", + std::make_error_code(std::errc::executable_format_error)); + default: + Records.emplace_back(); + auto &Record = Records.back(); + Record.RecordType = 0; // Record is type NORMAL. + // Strip off record type bit and use the next three bits. + uint8_t RecordType = (RecordFirstByte >> 1) & 0x07; + switch (RecordType) { + case static_cast<uint8_t>(RecordTypes::ENTER): + Record.Type = RecordTypes::ENTER; + break; + case static_cast<uint8_t>(RecordTypes::EXIT): + case 2: // TAIL_EXIT is not yet defined in RecordTypes. + Record.Type = RecordTypes::EXIT; + break; + default: + // When initializing the error, convert to uint16_t so that the record + // type isn't interpreted as a char. + return make_error<StringError>( + Twine("Illegal function record type: ") + .concat(Twine(static_cast<unsigned>(RecordType))), + std::make_error_code(std::errc::executable_format_error)); + } + Record.CPU = State.CPUId; + Record.TId = State.ThreadId; + // Back up to read first 32 bits, including the 8 we pulled RecordType + // and RecordKind out of. The remaining 28 are FunctionId. + uint32_t OffsetPtr = 0; + // Despite function Id being a signed int on XRayRecord, + // when it is written to an FDR format, the top bits are truncated, + // so it is effectively an unsigned value. When we shift off the + // top four bits, we want the shift to be logical, so we read as + // uint32_t. + uint32_t FuncIdBitField = RecordExtractor.getU32(&OffsetPtr); + Record.FuncId = FuncIdBitField >> 4; + // FunctionRecords have a 32 bit delta from the previous absolute TSC + // or TSC delta. If this would overflow, we should read a TSCWrap record + // with an absolute TSC reading. + uint64_t new_tsc = State.BaseTSC + RecordExtractor.getU32(&OffsetPtr); + State.BaseTSC = new_tsc; + Record.TSC = new_tsc; + } + return Error::success(); +} + +/// Reads a log in FDR mode for version 1 of this binary format. FDR mode is +/// defined as part of the compiler-rt project in xray_fdr_logging.h, and such +/// a log consists of the familiar 32 bit XRayHeader, followed by sequences of +/// of interspersed 16 byte Metadata Records and 8 byte Function Records. +/// +/// The following is an attempt to document the grammar of the format, which is +/// parsed by this function for little-endian machines. Since the format makes +/// use of BitFields, when we support big-Endian architectures, we will need to +/// adjust not only the endianness parameter to llvm's RecordExtractor, but also +/// the bit twiddling logic, which is consistent with the little-endian +/// convention that BitFields within a struct will first be packed into the +/// least significant bits the address they belong to. +/// +/// We expect a format complying with the grammar in the following pseudo-EBNF. +/// +/// FDRLog: XRayFileHeader ThreadBuffer* +/// XRayFileHeader: 32 bits to identify the log as FDR with machine metadata. +/// ThreadBuffer: BufSize NewBuffer WallClockTime NewCPUId FunctionSequence EOB +/// BufSize: 8 byte unsigned integer indicating how large the buffer is. +/// NewBuffer: 16 byte metadata record with Thread Id. +/// WallClockTime: 16 byte metadata record with human readable time. +/// NewCPUId: 16 byte metadata record with CPUId and a 64 bit TSC reading. +/// EOB: 16 byte record in a thread buffer plus mem garbage to fill BufSize. +/// FunctionSequence: NewCPUId | TSCWrap | FunctionRecord +/// TSCWrap: 16 byte metadata record with a full 64 bit TSC reading. +/// FunctionRecord: 8 byte record with FunctionId, entry/exit, and TSC delta. +Error loadFDRLog(StringRef Data, XRayFileHeader &FileHeader, + std::vector<XRayRecord> &Records) { + if (Data.size() < 32) + return make_error<StringError>( + "Not enough bytes for an XRay log.", + std::make_error_code(std::errc::invalid_argument)); + + // For an FDR log, there are records sized 16 and 8 bytes. + // There actually may be no records if no non-trivial functions are + // instrumented. + if (Data.size() % 8 != 0) + return make_error<StringError>( + "Invalid-sized XRay data.", + std::make_error_code(std::errc::invalid_argument)); + + if (auto E = readBinaryFormatHeader(Data, FileHeader)) + return E; + + uint64_t BufferSize = 0; + { + StringRef ExtraDataRef(FileHeader.FreeFormData, 16); + DataExtractor ExtraDataExtractor(ExtraDataRef, true, 8); + uint32_t ExtraDataOffset = 0; + BufferSize = ExtraDataExtractor.getU64(&ExtraDataOffset); + } + FDRState State{0, 0, 0, FDRState::Token::NEW_BUFFER_RECORD_OR_EOF, + BufferSize, 0}; + // RecordSize will tell the loop how far to seek ahead based on the record + // type that we have just read. + size_t RecordSize = 0; + for (auto S = Data.drop_front(32); !S.empty(); S = S.drop_front(RecordSize)) { + DataExtractor RecordExtractor(S, true, 8); + uint32_t OffsetPtr = 0; + if (State.Expects == FDRState::Token::SCAN_TO_END_OF_THREAD_BUF) { + RecordSize = State.CurrentBufferSize - State.CurrentBufferConsumed; + if (S.size() < State.CurrentBufferSize - State.CurrentBufferConsumed) { + return make_error<StringError>( + Twine("Incomplete thread buffer. Expected ") + + Twine(State.CurrentBufferSize - State.CurrentBufferConsumed) + + " remaining bytes but found " + Twine(S.size()), + make_error_code(std::errc::invalid_argument)); + } + State.CurrentBufferConsumed = 0; + State.Expects = FDRState::Token::NEW_BUFFER_RECORD_OR_EOF; + continue; + } + uint8_t BitField = RecordExtractor.getU8(&OffsetPtr); + bool isMetadataRecord = BitField & 0x01uL; + if (isMetadataRecord) { + RecordSize = 16; + if (auto E = processFDRMetadataRecord(State, BitField, RecordExtractor, + RecordSize)) + return E; + State.CurrentBufferConsumed += RecordSize; + } else { // Process Function Record + RecordSize = 8; + if (auto E = processFDRFunctionRecord(State, BitField, RecordExtractor, + Records)) + return E; + State.CurrentBufferConsumed += RecordSize; + } + } + // There are two conditions + if (State.Expects != FDRState::Token::NEW_BUFFER_RECORD_OR_EOF && + !(State.Expects == FDRState::Token::SCAN_TO_END_OF_THREAD_BUF && + State.CurrentBufferSize == State.CurrentBufferConsumed)) + return make_error<StringError>( + Twine("Encountered EOF with unexpected state expectation ") + + fdrStateToTwine(State.Expects) + + ". Remaining expected bytes in thread buffer total " + + Twine(State.CurrentBufferSize - State.CurrentBufferConsumed), + std::make_error_code(std::errc::executable_format_error)); + + return Error::success(); +} +Error loadYAMLLog(StringRef Data, XRayFileHeader &FileHeader, + std::vector<XRayRecord> &Records) { // Load the documents from the MappedFile. YAMLXRayTrace Trace; Input In(Data); @@ -175,14 +531,21 @@ Expected<Trace> llvm::xray::loadTraceFile(StringRef Filename, bool Sort) { uint16_t Version = HeaderExtractor.getU16(&OffsetPtr); uint16_t Type = HeaderExtractor.getU16(&OffsetPtr); + enum BinaryFormatType { NAIVE_FORMAT = 0, FLIGHT_DATA_RECORDER_FORMAT = 1 }; + Trace T; - if (Version == 1 && (Type == 0 || Type == 1)) { - if (auto E = NaiveLogLoader(StringRef(MappedFile.data(), MappedFile.size()), - T.FileHeader, T.Records)) + if (Version == 1 && Type == NAIVE_FORMAT) { + if (auto E = + loadNaiveFormatLog(StringRef(MappedFile.data(), MappedFile.size()), + T.FileHeader, T.Records)) + return std::move(E); + } else if (Version == 1 && Type == FLIGHT_DATA_RECORDER_FORMAT) { + if (auto E = loadFDRLog(StringRef(MappedFile.data(), MappedFile.size()), + T.FileHeader, T.Records)) return std::move(E); } else { - if (auto E = YAMLLogLoader(StringRef(MappedFile.data(), MappedFile.size()), - T.FileHeader, T.Records)) + if (auto E = loadYAMLLog(StringRef(MappedFile.data(), MappedFile.size()), + T.FileHeader, T.Records)) return std::move(E); } |