148 lines · cpp
1//===- FDRTraceWriter.cpp - XRay FDR Trace Writer ---------------*- 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-exception6//7//===----------------------------------------------------------------------===//8//9// Test a utility that can write out XRay FDR Mode formatted trace files.10//11//===----------------------------------------------------------------------===//12#include "llvm/XRay/FDRTraceWriter.h"13#include <tuple>14 15using namespace llvm;16using namespace llvm::xray;17 18namespace {19 20template <size_t Index> struct IndexedWriter {21 template <22 class Tuple,23 std::enable_if_t<(Index <24 std::tuple_size<std::remove_reference_t<Tuple>>::value),25 int> = 0>26 static size_t write(support::endian::Writer &OS, Tuple &&T) {27 OS.write(std::get<Index>(T));28 return sizeof(std::get<Index>(T)) + IndexedWriter<Index + 1>::write(OS, T);29 }30 31 template <32 class Tuple,33 std::enable_if_t<(Index >=34 std::tuple_size<std::remove_reference_t<Tuple>>::value),35 int> = 0>36 static size_t write(support::endian::Writer &OS, Tuple &&) {37 return 0;38 }39};40} // namespace41 42template <uint8_t Kind, class... Values>43static Error writeMetadata(support::endian::Writer &OS, Values &&...Ds) {44 // The first bit in the first byte of metadata records is always set to 1, so45 // we ensure this is the case when we write out the first byte of the record.46 uint8_t FirstByte = (static_cast<uint8_t>(Kind) << 1) | uint8_t{0x01u};47 auto T = std::make_tuple(std::forward<Values>(std::move(Ds))...);48 // Write in field order.49 OS.write(FirstByte);50 auto Bytes = IndexedWriter<0>::write(OS, T);51 assert(Bytes <= 15 && "Must only ever write at most 16 byte metadata!");52 // Pad out with appropriate numbers of zero's.53 for (; Bytes < 15; ++Bytes)54 OS.write('\0');55 return Error::success();56}57 58FDRTraceWriter::FDRTraceWriter(raw_ostream &O, const XRayFileHeader &H)59 : OS(O, llvm::endianness::native) {60 // We need to re-construct a header, by writing the fields we care about for61 // traces, in the format that the runtime would have written.62 uint32_t BitField =63 (H.ConstantTSC ? 0x01 : 0x0) | (H.NonstopTSC ? 0x02 : 0x0);64 65 // For endian-correctness, we need to write these fields in the order they66 // appear and that we expect, instead of blasting bytes of the struct through.67 OS.write(H.Version);68 OS.write(H.Type);69 OS.write(BitField);70 OS.write(H.CycleFrequency);71 ArrayRef<char> FreeFormBytes(H.FreeFormData,72 sizeof(XRayFileHeader::FreeFormData));73 OS.write(FreeFormBytes);74}75 76FDRTraceWriter::~FDRTraceWriter() = default;77 78Error FDRTraceWriter::visit(BufferExtents &R) {79 return writeMetadata<7u>(OS, R.size());80}81 82Error FDRTraceWriter::visit(WallclockRecord &R) {83 return writeMetadata<4u>(OS, R.seconds(), R.nanos());84}85 86Error FDRTraceWriter::visit(NewCPUIDRecord &R) {87 return writeMetadata<2u>(OS, R.cpuid(), R.tsc());88}89 90Error FDRTraceWriter::visit(TSCWrapRecord &R) {91 return writeMetadata<3u>(OS, R.tsc());92}93 94Error FDRTraceWriter::visit(CustomEventRecord &R) {95 if (auto E = writeMetadata<5u>(OS, R.size(), R.tsc(), R.cpu()))96 return E;97 auto D = R.data();98 ArrayRef<char> Bytes(D);99 OS.write(Bytes);100 return Error::success();101}102 103Error FDRTraceWriter::visit(CustomEventRecordV5 &R) {104 if (auto E = writeMetadata<5u>(OS, R.size(), R.delta()))105 return E;106 auto D = R.data();107 ArrayRef<char> Bytes(D);108 OS.write(Bytes);109 return Error::success();110}111 112Error FDRTraceWriter::visit(TypedEventRecord &R) {113 if (auto E = writeMetadata<8u>(OS, R.size(), R.delta(), R.eventType()))114 return E;115 auto D = R.data();116 ArrayRef<char> Bytes(D);117 OS.write(Bytes);118 return Error::success();119}120 121Error FDRTraceWriter::visit(CallArgRecord &R) {122 return writeMetadata<6u>(OS, R.arg());123}124 125Error FDRTraceWriter::visit(PIDRecord &R) {126 return writeMetadata<9u>(OS, R.pid());127}128 129Error FDRTraceWriter::visit(NewBufferRecord &R) {130 return writeMetadata<0u>(OS, R.tid());131}132 133Error FDRTraceWriter::visit(EndBufferRecord &R) {134 return writeMetadata<1u>(OS, 0);135}136 137Error FDRTraceWriter::visit(FunctionRecord &R) {138 // Write out the data in "field" order, to be endian-aware.139 uint32_t TypeRecordFuncId = uint32_t{R.functionId() & ~uint32_t{0x0Fu << 28}};140 TypeRecordFuncId <<= 3;141 TypeRecordFuncId |= static_cast<uint32_t>(R.recordType());142 TypeRecordFuncId <<= 1;143 TypeRecordFuncId &= ~uint32_t{0x01};144 OS.write(TypeRecordFuncId);145 OS.write(R.delta());146 return Error::success();147}148