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llvm-mirror/lib/XRay/Trace.cpp
Dean Michael Berris f9e1fbc647 [XRay] Refactor file header reading (NFC) 
Summary:
This patch moves out the definition of the XRay log file header from
binary logs into its own header and implementation file.

This is one part of the refactoring being done in D50441.

Reviewers: eizan

Subscribers: mgorny, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D51086

llvm-svn: 340389
2018-08-22 07:37:55 +00:00

924 lines
37 KiB
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//===- Trace.cpp - XRay Trace Loading implementation. ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// XRay log reader implementation.
//
//===----------------------------------------------------------------------===//
#include "llvm/XRay/Trace.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/XRay/FileHeaderReader.h"
#include "llvm/XRay/YAMLXRayRecord.h"
using namespace llvm;
using namespace llvm::xray;
using llvm::yaml::Input;
namespace {
using XRayRecordStorage =
std::aligned_storage<sizeof(XRayRecord), alignof(XRayRecord)>::type;
// This is the number of bytes in the "body" of a MetadataRecord in FDR Mode.
// This already excludes the first byte, which indicates the type of metadata
// record it is.
constexpr auto kFDRMetadataBodySize = 15;
Error loadNaiveFormatLog(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));
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 Reader(Data, true, 8);
uint32_t OffsetPtr = 0;
auto FileHeaderOrError = readBinaryFormatHeader(Reader, OffsetPtr);
if (!FileHeaderOrError)
return FileHeaderOrError.takeError();
FileHeader = std::move(FileHeaderOrError.get());
// Each record after the header will be 32 bytes, in the following format:
//
// (2) uint16 : record type
// (1) uint8 : cpu id
// (1) uint8 : type
// (4) sint32 : function id
// (8) uint64 : tsc
// (4) uint32 : thread id
// (4) uint32 : process id
// (8) - : padding
while (Reader.isValidOffset(OffsetPtr)) {
if (!Reader.isValidOffsetForDataOfSize(OffsetPtr, 32))
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Not enough bytes to read a full record at offset %d.", OffsetPtr);
auto PreReadOffset = OffsetPtr;
auto RecordType = Reader.getU16(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading record type at offset %d.", OffsetPtr);
switch (RecordType) {
case 0: { // Normal records.
Records.emplace_back();
auto &Record = Records.back();
Record.RecordType = RecordType;
PreReadOffset = OffsetPtr;
Record.CPU = Reader.getU8(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading CPU field at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
auto Type = Reader.getU8(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading record type field at offset %d.", OffsetPtr);
switch (Type) {
case 0:
Record.Type = RecordTypes::ENTER;
break;
case 1:
Record.Type = RecordTypes::EXIT;
break;
case 2:
Record.Type = RecordTypes::TAIL_EXIT;
break;
case 3:
Record.Type = RecordTypes::ENTER_ARG;
break;
default:
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Unknown record type '%d' at offset %d.", Type, OffsetPtr);
}
PreReadOffset = OffsetPtr;
Record.FuncId = Reader.getSigned(&OffsetPtr, sizeof(int32_t));
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading function id field at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
Record.TSC = Reader.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading TSC field at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
Record.TId = Reader.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading thread id field at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
Record.PId = Reader.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading process id at offset %d.", OffsetPtr);
break;
}
case 1: { // Arg payload record.
auto &Record = Records.back();
// We skip the next two bytes of the record, because we don't need the
// type and the CPU record for arg payloads.
OffsetPtr += 2;
PreReadOffset = OffsetPtr;
int32_t FuncId = Reader.getSigned(&OffsetPtr, sizeof(int32_t));
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading function id field at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
auto TId = Reader.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading thread id field at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
auto PId = Reader.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading process id field at offset %d.", OffsetPtr);
// Make a check for versions above 3 for the Pid field
if (Record.FuncId != FuncId || Record.TId != TId ||
(FileHeader.Version >= 3 ? Record.PId != PId : false))
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Corrupted log, found arg payload following non-matching "
"function+thread record. Record for function %d != %d at offset "
"%d",
Record.FuncId, FuncId, OffsetPtr);
PreReadOffset = OffsetPtr;
auto Arg = Reader.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading argument payload at offset %d.", OffsetPtr);
Record.CallArgs.push_back(Arg);
break;
}
default:
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Unknown record type '%d' at offset %d.", RecordType, OffsetPtr);
}
// Advance the offset pointer enough bytes to align to 32-byte records for
// basic mode logs.
OffsetPtr += 8;
}
return Error::success();
}
/// 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;
int32_t ProcessId;
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,
CALL_ARGUMENT,
BUFFER_EXTENTS,
PID_RECORD,
};
Token Expects;
// Each threads buffer may have trailing garbage to scan over, so we track our
// progress.
uint64_t CurrentBufferSize;
uint64_t CurrentBufferConsumed;
};
const char *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";
case FDRState::Token::CALL_ARGUMENT:
return "CALL_ARGUMENT";
case FDRState::Token::BUFFER_EXTENTS:
return "BUFFER_EXTENTS";
case FDRState::Token::PID_RECORD:
return "PID_RECORD";
}
return "UNKNOWN";
}
/// State transition when a NewBufferRecord is encountered.
Error processFDRNewBufferRecord(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr) {
if (State.Expects != FDRState::Token::NEW_BUFFER_RECORD_OR_EOF)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Malformed log: Read New Buffer record kind out of sequence; expected: "
"%s at offset %d.",
fdrStateToTwine(State.Expects), OffsetPtr);
auto PreReadOffset = OffsetPtr;
State.ThreadId = RecordExtractor.getU16(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading the thread id at offset %d.", OffsetPtr);
State.Expects = FDRState::Token::WALLCLOCK_RECORD;
// Advance the offset pointer by enough bytes representing the remaining
// padding in a metadata record.
OffsetPtr += kFDRMetadataBodySize - 2;
assert(OffsetPtr - PreReadOffset == kFDRMetadataBodySize);
return Error::success();
}
/// State transition when an EndOfBufferRecord is encountered.
Error processFDREndOfBufferRecord(FDRState &State, uint32_t &OffsetPtr) {
if (State.Expects == FDRState::Token::NEW_BUFFER_RECORD_OR_EOF)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Malformed log: Received EOB message without current buffer; expected: "
"%s at offset %d.",
fdrStateToTwine(State.Expects), OffsetPtr);
State.Expects = FDRState::Token::SCAN_TO_END_OF_THREAD_BUF;
// Advance the offset pointer by enough bytes representing the remaining
// padding in a metadata record.
OffsetPtr += kFDRMetadataBodySize;
return Error::success();
}
/// State transition when a NewCPUIdRecord is encountered.
Error processFDRNewCPUIdRecord(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr) {
if (State.Expects != FDRState::Token::FUNCTION_SEQUENCE &&
State.Expects != FDRState::Token::NEW_CPU_ID_RECORD)
return make_error<StringError>(
Twine("Malformed log. Read NewCPUId record kind out of sequence; "
"expected: ") +
fdrStateToTwine(State.Expects),
std::make_error_code(std::errc::executable_format_error));
auto BeginOffset = OffsetPtr;
auto PreReadOffset = OffsetPtr;
State.CPUId = RecordExtractor.getU16(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading the CPU field at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
State.BaseTSC = RecordExtractor.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading the base TSC field at offset %d.", OffsetPtr);
State.Expects = FDRState::Token::FUNCTION_SEQUENCE;
// Advance the offset pointer by a few bytes, to account for the padding in
// CPU ID metadata records that we've already advanced through.
OffsetPtr += kFDRMetadataBodySize - (OffsetPtr - BeginOffset);
assert(OffsetPtr - BeginOffset == kFDRMetadataBodySize);
return Error::success();
}
/// State transition when a TSCWrapRecord (overflow detection) is encountered.
Error processFDRTSCWrapRecord(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr) {
if (State.Expects != FDRState::Token::FUNCTION_SEQUENCE)
return make_error<StringError>(
Twine("Malformed log. Read TSCWrap record kind out of sequence; "
"expecting: ") +
fdrStateToTwine(State.Expects),
std::make_error_code(std::errc::executable_format_error));
auto PreReadOffset = OffsetPtr;
State.BaseTSC = RecordExtractor.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading the base TSC field at offset %d.", OffsetPtr);
// Advance the offset pointer by a few more bytes, accounting for the padding
// in the metadata record after reading the base TSC.
OffsetPtr += kFDRMetadataBodySize - 8;
assert(OffsetPtr - PreReadOffset == kFDRMetadataBodySize);
return Error::success();
}
/// State transition when a WallTimeMarkerRecord is encountered.
Error processFDRWallTimeRecord(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr) {
if (State.Expects != FDRState::Token::WALLCLOCK_RECORD)
return make_error<StringError>(
Twine("Malformed log. Read Wallclock record kind out of sequence; "
"expecting: ") +
fdrStateToTwine(State.Expects),
std::make_error_code(std::errc::executable_format_error));
// Read in the data from the walltime record.
auto PreReadOffset = OffsetPtr;
auto WallTime = RecordExtractor.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading the walltime record at offset %d.", OffsetPtr);
// TODO: Someday, reconcile the TSC ticks to wall clock time for presentation
// purposes. For now, we're ignoring these records.
(void)WallTime;
State.Expects = FDRState::Token::NEW_CPU_ID_RECORD;
// Advance the offset pointer by a few more bytes, accounting for the padding
// in the metadata record after reading in the walltime data.
OffsetPtr += kFDRMetadataBodySize - 8;
assert(OffsetPtr - PreReadOffset == kFDRMetadataBodySize);
return Error::success();
}
/// State transition when a PidRecord is encountered.
Error processFDRPidRecord(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr) {
if (State.Expects != FDRState::Token::PID_RECORD)
return make_error<StringError>(
Twine("Malformed log. Read Pid record kind out of sequence; "
"expected: ") +
fdrStateToTwine(State.Expects),
std::make_error_code(std::errc::executable_format_error));
auto PreReadOffset = OffsetPtr;
State.ProcessId = RecordExtractor.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading the process ID at offset %d.", OffsetPtr);
State.Expects = FDRState::Token::NEW_CPU_ID_RECORD;
// Advance the offset pointer by a few more bytes, accounting for the padding
// in the metadata record after reading in the PID.
OffsetPtr += kFDRMetadataBodySize - 4;
assert(OffsetPtr - PreReadOffset == kFDRMetadataBodySize);
return Error::success();
}
/// State transition when a CustomEventMarker is encountered.
Error processCustomEventMarker(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr) {
// We can encounter a CustomEventMarker anywhere in the log, so we can handle
// it regardless of the expectation. However, we do set the expectation to
// read a set number of fixed bytes, as described in the metadata.
auto BeginOffset = OffsetPtr;
auto PreReadOffset = OffsetPtr;
uint32_t DataSize = RecordExtractor.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading a custom event marker at offset %d.", OffsetPtr);
PreReadOffset = OffsetPtr;
uint64_t TSC = RecordExtractor.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading the TSC at offset %d.", OffsetPtr);
// FIXME: Actually represent the record through the API. For now we only
// skip through the data.
(void)TSC;
// Advance the offset ptr by the size of the data associated with the custom
// event, as well as the padding associated with the remainder of the metadata
// record.
OffsetPtr += (kFDRMetadataBodySize - (OffsetPtr - BeginOffset)) + DataSize;
if (!RecordExtractor.isValidOffset(OffsetPtr))
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Reading custom event data moves past addressable trace data (starting "
"at offset %d, advancing to offset %d).",
BeginOffset, OffsetPtr);
return Error::success();
}
/// State transition when an BufferExtents record is encountered.
Error processBufferExtents(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr) {
if (State.Expects != FDRState::Token::BUFFER_EXTENTS)
return make_error<StringError>(
Twine("Malformed log. Buffer Extents unexpected; expected: ") +
fdrStateToTwine(State.Expects),
std::make_error_code(std::errc::executable_format_error));
auto PreReadOffset = OffsetPtr;
State.CurrentBufferSize = RecordExtractor.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed to read current buffer size at offset %d.", OffsetPtr);
State.Expects = FDRState::Token::NEW_BUFFER_RECORD_OR_EOF;
// Advance the offset pointer by enough bytes accounting for the padding in a
// metadata record, after we read in the buffer extents.
OffsetPtr += kFDRMetadataBodySize - 8;
return Error::success();
}
/// State transition when a CallArgumentRecord is encountered.
Error processFDRCallArgumentRecord(FDRState &State,
DataExtractor &RecordExtractor,
std::vector<XRayRecord> &Records,
uint32_t &OffsetPtr) {
auto &Enter = Records.back();
if (Enter.Type != RecordTypes::ENTER && Enter.Type != RecordTypes::ENTER_ARG)
return make_error<StringError>(
"CallArgument needs to be right after a function entry",
std::make_error_code(std::errc::executable_format_error));
auto PreReadOffset = OffsetPtr;
auto Arg = RecordExtractor.getU64(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed to read argument record at offset %d.", OffsetPtr);
Enter.Type = RecordTypes::ENTER_ARG;
Enter.CallArgs.emplace_back(Arg);
// Advance the offset pointer by enough bytes accounting for the padding in a
// metadata record, after reading the payload.
OffsetPtr += kFDRMetadataBodySize - 8;
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.
///
/// Beginning with Version 2 of the FDR log, we do not depend on the size of the
/// buffer, but rather use the extents to determine how far to read in the log
/// for this particular buffer.
///
/// In Version 3, FDR log now includes a pid metadata record after
/// WallTimeMarker
Error processFDRMetadataRecord(FDRState &State, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr,
std::vector<XRayRecord> &Records,
uint16_t Version, uint8_t FirstByte) {
// The remaining 7 bits of the first byte are the RecordKind enum for each
// Metadata Record.
switch (FirstByte >> 1) {
case 0: // NewBuffer
if (auto E = processFDRNewBufferRecord(State, RecordExtractor, OffsetPtr))
return E;
break;
case 1: // EndOfBuffer
if (Version >= 2)
return make_error<StringError>(
"Since Version 2 of FDR logging, we no longer support EOB records.",
std::make_error_code(std::errc::executable_format_error));
if (auto E = processFDREndOfBufferRecord(State, OffsetPtr))
return E;
break;
case 2: // NewCPUId
if (auto E = processFDRNewCPUIdRecord(State, RecordExtractor, OffsetPtr))
return E;
break;
case 3: // TSCWrap
if (auto E = processFDRTSCWrapRecord(State, RecordExtractor, OffsetPtr))
return E;
break;
case 4: // WallTimeMarker
if (auto E = processFDRWallTimeRecord(State, RecordExtractor, OffsetPtr))
return E;
// In Version 3 and and above, a PidRecord is expected after WallTimeRecord
if (Version >= 3)
State.Expects = FDRState::Token::PID_RECORD;
break;
case 5: // CustomEventMarker
if (auto E = processCustomEventMarker(State, RecordExtractor, OffsetPtr))
return E;
break;
case 6: // CallArgument
if (auto E = processFDRCallArgumentRecord(State, RecordExtractor, Records,
OffsetPtr))
return E;
break;
case 7: // BufferExtents
if (auto E = processBufferExtents(State, RecordExtractor, OffsetPtr))
return E;
break;
case 9: // Pid
if (auto E = processFDRPidRecord(State, RecordExtractor, OffsetPtr))
return E;
break;
default:
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Illegal metadata record type: '%d' at offset %d.", FirstByte >> 1,
OffsetPtr);
}
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, DataExtractor &RecordExtractor,
uint32_t &OffsetPtr, uint8_t FirstByte,
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::PID_RECORD:
return make_error<StringError>(
"Malformed log. Received Function Record when expecting pid.",
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.
auto T = (FirstByte >> 1) & 0x07;
switch (T) {
case static_cast<decltype(T)>(RecordTypes::ENTER):
Record.Type = RecordTypes::ENTER;
break;
case static_cast<decltype(T)>(RecordTypes::EXIT):
Record.Type = RecordTypes::EXIT;
break;
case static_cast<decltype(T)>(RecordTypes::TAIL_EXIT):
Record.Type = RecordTypes::TAIL_EXIT;
break;
case static_cast<decltype(T)>(RecordTypes::ENTER_ARG):
Record.Type = RecordTypes::ENTER_ARG;
State.Expects = FDRState::Token::CALL_ARGUMENT;
break;
default:
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Illegal function record type '%d' at offset %d.", T, OffsetPtr);
}
Record.CPU = State.CPUId;
Record.TId = State.ThreadId;
Record.PId = State.ProcessId;
// Back up one byte to re-read the first byte, which is important for
// computing the function id for a record.
--OffsetPtr;
// 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.
auto PreReadOffset = OffsetPtr;
uint32_t FuncIdBitField = RecordExtractor.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading truncated function id field at offset %d.",
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.
PreReadOffset = OffsetPtr;
uint64_t NewTSC = State.BaseTSC + RecordExtractor.getU32(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading TSC delta at offset %d.", OffsetPtr);
State.BaseTSC = NewTSC;
Record.TSC = NewTSC;
}
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
/// in Version 1 of the FDR log.
///
/// FDRLog: XRayFileHeader ThreadBuffer*
/// XRayFileHeader: 32 bytes to identify the log as FDR with machine metadata.
/// Includes BufferSize
/// ThreadBuffer: 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.
/// Pid: 16 byte metadata record with Pid
/// 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.
///
/// In Version 2, we make the following changes:
///
/// ThreadBuffer: BufferExtents NewBuffer WallClockTime NewCPUId
/// FunctionSequence
/// BufferExtents: 16 byte metdata record describing how many usable bytes are
/// in the buffer. This is measured from the start of the buffer
/// and must always be at least 48 (bytes).
///
/// In Version 3, we make the following changes:
///
/// ThreadBuffer: BufferExtents NewBuffer WallClockTime Pid NewCPUId
/// FunctionSequence
/// EOB: *deprecated*
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));
DataExtractor Reader(Data, true, 8);
uint32_t OffsetPtr = 0;
auto FileHeaderOrError = readBinaryFormatHeader(Reader, OffsetPtr);
if (!FileHeaderOrError)
return FileHeaderOrError.takeError();
FileHeader = std::move(FileHeaderOrError.get());
uint64_t BufferSize = 0;
{
StringRef ExtraDataRef(FileHeader.FreeFormData, 16);
DataExtractor ExtraDataExtractor(ExtraDataRef, true, 8);
uint32_t ExtraDataOffset = 0;
BufferSize = ExtraDataExtractor.getU64(&ExtraDataOffset);
}
FDRState::Token InitialExpectation;
switch (FileHeader.Version) {
case 1:
InitialExpectation = FDRState::Token::NEW_BUFFER_RECORD_OR_EOF;
break;
case 2:
case 3:
InitialExpectation = FDRState::Token::BUFFER_EXTENTS;
break;
default:
return make_error<StringError>(
Twine("Unsupported version '") + Twine(FileHeader.Version) + "'",
std::make_error_code(std::errc::executable_format_error));
}
FDRState State{0, 0, 0, 0, InitialExpectation, BufferSize, 0};
// RecordSize will tell the loop how far to seek ahead based on the record
// type that we have just read.
while (Reader.isValidOffset(OffsetPtr)) {
auto BeginOffset = OffsetPtr;
if (State.Expects == FDRState::Token::SCAN_TO_END_OF_THREAD_BUF) {
OffsetPtr += State.CurrentBufferSize - State.CurrentBufferConsumed;
State.CurrentBufferConsumed = 0;
State.Expects = FDRState::Token::NEW_BUFFER_RECORD_OR_EOF;
continue;
}
auto PreReadOffset = OffsetPtr;
uint8_t BitField = Reader.getU8(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading first byte of record at offset %d.", OffsetPtr);
bool isMetadataRecord = BitField & 0x01uL;
bool isBufferExtents =
(BitField >> 1) == 7; // BufferExtents record kind == 7
if (isMetadataRecord) {
if (auto E = processFDRMetadataRecord(State, Reader, OffsetPtr, Records,
FileHeader.Version, BitField))
return E;
} else { // Process Function Record
if (auto E = processFDRFunctionRecord(State, Reader, OffsetPtr, BitField,
Records))
return E;
}
// The BufferExtents record is technically not part of the buffer, so we
// don't count the size of that record against the buffer's actual size.
if (!isBufferExtents)
State.CurrentBufferConsumed += OffsetPtr - BeginOffset;
assert(State.CurrentBufferConsumed <= State.CurrentBufferSize);
if ((FileHeader.Version == 2 || FileHeader.Version == 3) &&
State.CurrentBufferSize == State.CurrentBufferConsumed) {
// In Version 2 of the log, we don't need to scan to the end of the thread
// buffer if we've already consumed all the bytes we need to.
State.Expects = FDRState::Token::BUFFER_EXTENTS;
State.CurrentBufferSize = BufferSize;
State.CurrentBufferConsumed = 0;
}
}
// Having iterated over everything we've been given, we've either consumed
// everything and ended up in the end state, or were told to skip the rest.
bool Finished = State.Expects == FDRState::Token::SCAN_TO_END_OF_THREAD_BUF &&
State.CurrentBufferSize == State.CurrentBufferConsumed;
if ((State.Expects != FDRState::Token::NEW_BUFFER_RECORD_OR_EOF &&
State.Expects != FDRState::Token::BUFFER_EXTENTS) &&
!Finished)
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) {
YAMLXRayTrace Trace;
Input In(Data);
In >> Trace;
if (In.error())
return make_error<StringError>("Failed loading YAML Data.", In.error());
FileHeader.Version = Trace.Header.Version;
FileHeader.Type = Trace.Header.Type;
FileHeader.ConstantTSC = Trace.Header.ConstantTSC;
FileHeader.NonstopTSC = Trace.Header.NonstopTSC;
FileHeader.CycleFrequency = Trace.Header.CycleFrequency;
if (FileHeader.Version != 1)
return make_error<StringError>(
Twine("Unsupported XRay file version: ") + Twine(FileHeader.Version),
std::make_error_code(std::errc::invalid_argument));
Records.clear();
std::transform(Trace.Records.begin(), Trace.Records.end(),
std::back_inserter(Records), [&](const YAMLXRayRecord &R) {
return XRayRecord{R.RecordType, R.CPU, R.Type, R.FuncId,
R.TSC, R.TId, R.PId, R.CallArgs};
});
return Error::success();
}
} // namespace
Expected<Trace> llvm::xray::loadTraceFile(StringRef Filename, bool Sort) {
int Fd;
if (auto EC = sys::fs::openFileForRead(Filename, Fd)) {
return make_error<StringError>(
Twine("Cannot read log from '") + Filename + "'", EC);
}
uint64_t FileSize;
if (auto EC = sys::fs::file_size(Filename, FileSize)) {
return make_error<StringError>(
Twine("Cannot read log from '") + Filename + "'", EC);
}
if (FileSize < 4) {
return make_error<StringError>(
Twine("File '") + Filename + "' too small for XRay.",
std::make_error_code(std::errc::executable_format_error));
}
// Map the opened file into memory and use a StringRef to access it later.
std::error_code EC;
sys::fs::mapped_file_region MappedFile(
Fd, sys::fs::mapped_file_region::mapmode::readonly, FileSize, 0, EC);
if (EC) {
return make_error<StringError>(
Twine("Cannot read log from '") + Filename + "'", EC);
}
auto Data = StringRef(MappedFile.data(), MappedFile.size());
// Attempt to detect the file type using file magic. We have a slight bias
// towards the binary format, and we do this by making sure that the first 4
// bytes of the binary file is some combination of the following byte
// patterns: (observe the code loading them assumes they're little endian)
//
// 0x01 0x00 0x00 0x00 - version 1, "naive" format
// 0x01 0x00 0x01 0x00 - version 1, "flight data recorder" format
// 0x02 0x00 0x01 0x00 - version 2, "flight data recorder" format
//
// YAML files don't typically have those first four bytes as valid text so we
// try loading assuming YAML if we don't find these bytes.
//
// Only if we can't load either the binary or the YAML format will we yield an
// error.
StringRef Magic(MappedFile.data(), 4);
DataExtractor HeaderExtractor(Magic, true, 8);
uint32_t OffsetPtr = 0;
uint16_t Version = HeaderExtractor.getU16(&OffsetPtr);
uint16_t Type = HeaderExtractor.getU16(&OffsetPtr);
enum BinaryFormatType { NAIVE_FORMAT = 0, FLIGHT_DATA_RECORDER_FORMAT = 1 };
Trace T;
switch (Type) {
case NAIVE_FORMAT:
if (Version == 1 || Version == 2 || Version == 3) {
if (auto E = loadNaiveFormatLog(Data, T.FileHeader, T.Records))
return std::move(E);
} else {
return make_error<StringError>(
Twine("Unsupported version for Basic/Naive Mode logging: ") +
Twine(Version),
std::make_error_code(std::errc::executable_format_error));
}
break;
case FLIGHT_DATA_RECORDER_FORMAT:
if (Version == 1 || Version == 2 || Version == 3) {
if (auto E = loadFDRLog(Data, T.FileHeader, T.Records))
return std::move(E);
} else {
return make_error<StringError>(
Twine("Unsupported version for FDR Mode logging: ") + Twine(Version),
std::make_error_code(std::errc::executable_format_error));
}
break;
default:
if (auto E = loadYAMLLog(Data, T.FileHeader, T.Records))
return std::move(E);
}
if (Sort)
std::stable_sort(T.Records.begin(), T.Records.end(),
[&](const XRayRecord &L, const XRayRecord &R) {
return L.TSC < R.TSC;
});
return std::move(T);
}
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