llvm/llvm/lib/XRay/Trace.cpp

//===- Trace.cpp - XRay Trace Loading implementation. ---------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// 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/BlockIndexer.h"
#include "llvm/XRay/BlockVerifier.h"
#include "llvm/XRay/FDRRecordConsumer.h"
#include "llvm/XRay/FDRRecordProducer.h"
#include "llvm/XRay/FDRRecords.h"
#include "llvm/XRay/FDRTraceExpander.h"
#include "llvm/XRay/FileHeaderReader.h"
#include "llvm/XRay/YAMLXRayRecord.h"
#include <memory>
#include <vector>

usingnamespacellvm;
usingnamespacellvm::xray;
Input;

namespace {

Error loadNaiveFormatLog(StringRef Data, bool IsLittleEndian,
                         XRayFileHeader &FileHeader,
                         std::vector<XRayRecord> &Records) { … }

/// 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*
///
/// In Version 4, we make the following changes:
///
/// CustomEventRecord now includes the CPU data.
///
/// In Version 5, we make the following changes:
///
/// CustomEventRecord and TypedEventRecord now use TSC delta encoding similar to
/// what FunctionRecord instances use, and we no longer need to include the CPU
/// id in the CustomEventRecord.
///
Error loadFDRLog(StringRef Data, bool IsLittleEndian,
                 XRayFileHeader &FileHeader, std::vector<XRayRecord> &Records) { … }

Error loadYAMLLog(StringRef Data, XRayFileHeader &FileHeader,
                  std::vector<XRayRecord> &Records) { … }
} // namespace

Expected<Trace> llvm::xray::loadTraceFile(StringRef Filename, bool Sort) { … }

Expected<Trace> llvm::xray::loadTrace(const DataExtractor &DE, bool Sort) { … }