LLVM 22.0.0git
FDRTraceWriter.cpp
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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-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Test a utility that can write out XRay FDR Mode formatted trace files.
10//
11//===----------------------------------------------------------------------===//
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} // namespace
41
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, so
45 // 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
59 : OS(O, llvm::endianness::native) {
60 // We need to re-construct a header, by writing the fields we care about for
61 // 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 they
66 // 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,
73 OS.write(FreeFormBytes);
74}
75
77
81
83 return writeMetadata<4u>(OS, R.seconds(), R.nanos());
84}
85
87 return writeMetadata<2u>(OS, R.cpuid(), R.tsc());
88}
89
93
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
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
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
122 return writeMetadata<6u>(OS, R.arg());
123}
124
126 return writeMetadata<9u>(OS, R.pid());
127}
128
132
136
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}
assert(UImm &&(UImm !=~static_cast< T >(0)) &&"Invalid immediate!")
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
static Error writeMetadata(support::endian::Writer &OS, Values &&...Ds)
#define H(x, y, z)
Definition MD5.cpp:57
#define T
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition ArrayRef.h:41
Lightweight error class with error context and mandatory checking.
Definition Error.h:159
static ErrorSuccess success()
Create a success value.
Definition Error.h:336
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition raw_ostream.h:53
FDRTraceWriter(raw_ostream &O, const XRayFileHeader &H)
Error visit(BufferExtents &) override
This is an optimization pass for GlobalISel generic memory operations.
LLVM_ABI Error write(MCStreamer &Out, ArrayRef< std::string > Inputs, OnCuIndexOverflow OverflowOptValue)
Definition DWP.cpp:622
endianness
Definition bit.h:71
Adapter to write values to a stream in a particular byte order.
void write(ArrayRef< value_type > Val)
XRay traces all have a header providing some top-matter information useful to help tools determine ho...
Definition XRayRecord.h:26