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//===- FDRTraceWriter.cpp - XRay FDR Trace Writer ---------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Test a utility that can write out XRay FDR Mode formatted trace files.
//
//===----------------------------------------------------------------------===//
#include "llvm/XRay/FDRTraceWriter.h"
#include <tuple>
namespace llvm {
namespace xray {
namespace {
template <size_t Index> struct IndexedWriter {
template <
class Tuple,
typename std::enable_if<
(Index <
std::tuple_size<typename std::remove_reference<Tuple>::type>::value),
int>::type = 0>
static size_t write(support::endian::Writer &OS, Tuple &&T) {
OS.write(std::get<Index>(T));
return sizeof(std::get<Index>(T)) + IndexedWriter<Index + 1>::write(OS, T);
}
template <
class Tuple,
typename std::enable_if<
(Index >=
std::tuple_size<typename std::remove_reference<Tuple>::type>::value),
int>::type = 0>
static size_t write(support::endian::Writer &OS, Tuple &&) {
return 0;
}
};
template <uint8_t Kind, class... Values>
Error writeMetadata(support::endian::Writer &OS, Values &&... Ds) {
// The first bit in the first byte of metadata records is always set to 1, so
// we ensure this is the case when we write out the first byte of the record.
uint8_t FirstByte = (static_cast<uint8_t>(Kind) << 1) | uint8_t{0x01u};
auto T = std::make_tuple(std::forward<Values>(std::move(Ds))...);
// Write in field order.
OS.write(FirstByte);
auto Bytes = IndexedWriter<0>::write(OS, T);
assert(Bytes <= 15 && "Must only ever write at most 16 byte metadata!");
// Pad out with appropriate numbers of zero's.
for (; Bytes < 15; ++Bytes)
OS.write('\0');
return Error::success();
}
} // namespace
FDRTraceWriter::FDRTraceWriter(raw_ostream &O, const XRayFileHeader &H)
: OS(O, support::endianness::native) {
// We need to re-construct a header, by writing the fields we care about for
// traces, in the format that the runtime would have written.
uint32_t BitField =
(H.ConstantTSC ? 0x01 : 0x0) | (H.NonstopTSC ? 0x02 : 0x0);
// For endian-correctness, we need to write these fields in the order they
// appear and that we expect, instead of blasting bytes of the struct through.
OS.write(H.Version);
OS.write(H.Type);
OS.write(BitField);
OS.write(H.CycleFrequency);
ArrayRef<char> FreeFormBytes(H.FreeFormData,
sizeof(XRayFileHeader::FreeFormData));
OS.write(FreeFormBytes);
}
FDRTraceWriter::~FDRTraceWriter() {}
Error FDRTraceWriter::visit(BufferExtents &R) {
return writeMetadata<7u>(OS, R.size());
}
Error FDRTraceWriter::visit(WallclockRecord &R) {
return writeMetadata<4u>(OS, R.seconds(), R.nanos());
}
Error FDRTraceWriter::visit(NewCPUIDRecord &R) {
return writeMetadata<2u>(OS, R.cpuid(), R.tsc());
}
Error FDRTraceWriter::visit(TSCWrapRecord &R) {
return writeMetadata<3u>(OS, R.tsc());
}
Error FDRTraceWriter::visit(CustomEventRecord &R) {
if (auto E = writeMetadata<5u>(OS, R.size(), R.tsc(), R.cpu()))
return E;
auto D = R.data();
ArrayRef<char> Bytes(D.data(), D.size());
OS.write(Bytes);
return Error::success();
}
Error FDRTraceWriter::visit(CustomEventRecordV5 &R) {
if (auto E = writeMetadata<5u>(OS, R.size(), R.delta()))
return E;
auto D = R.data();
ArrayRef<char> Bytes(D.data(), D.size());
OS.write(Bytes);
return Error::success();
}
Error FDRTraceWriter::visit(TypedEventRecord &R) {
if (auto E = writeMetadata<8u>(OS, R.size(), R.delta(), R.eventType()))
return E;
auto D = R.data();
ArrayRef<char> Bytes(D.data(), D.size());
OS.write(Bytes);
return Error::success();
}
Error FDRTraceWriter::visit(CallArgRecord &R) {
return writeMetadata<6u>(OS, R.arg());
}
Error FDRTraceWriter::visit(PIDRecord &R) {
return writeMetadata<9u>(OS, R.pid());
}
Error FDRTraceWriter::visit(NewBufferRecord &R) {
return writeMetadata<0u>(OS, R.tid());
}
Error FDRTraceWriter::visit(EndBufferRecord &R) {
return writeMetadata<1u>(OS, 0);
}
Error FDRTraceWriter::visit(FunctionRecord &R) {
// Write out the data in "field" order, to be endian-aware.
uint32_t TypeRecordFuncId = uint32_t{R.functionId() & ~uint32_t{0x0Fu << 28}};
TypeRecordFuncId <<= 3;
TypeRecordFuncId |= static_cast<uint32_t>(R.recordType());
TypeRecordFuncId <<= 1;
TypeRecordFuncId &= ~uint32_t{0x01};
OS.write(TypeRecordFuncId);
OS.write(R.delta());
return Error::success();
}
} // namespace xray
} // namespace llvm