1 //=-- InstrProfWriter.cpp - Instrumented profiling writer -------------------=//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing profiling data for clang's
11 // instrumentation based PGO and coverage.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/ProfileData/InstrProfWriter.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/Support/EndianStream.h"
18 #include "llvm/Support/OnDiskHashTable.h"
23 static support::endianness ValueProfDataEndianness = support::little;
25 class InstrProfRecordTrait {
27 typedef StringRef key_type;
28 typedef StringRef key_type_ref;
30 typedef const InstrProfWriter::ProfilingData *const data_type;
31 typedef const InstrProfWriter::ProfilingData *const data_type_ref;
33 typedef uint64_t hash_value_type;
34 typedef uint64_t offset_type;
36 static hash_value_type ComputeHash(key_type_ref K) {
37 return IndexedInstrProf::ComputeHash(IndexedInstrProf::HashType, K);
40 static std::pair<offset_type, offset_type>
41 EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) {
42 using namespace llvm::support;
43 endian::Writer<little> LE(Out);
45 offset_type N = K.size();
46 LE.write<offset_type>(N);
49 for (const auto &ProfileData : *V) {
50 const InstrProfRecord &ProfRecord = ProfileData.second;
51 M += sizeof(uint64_t); // The function hash
52 M += sizeof(uint64_t); // The size of the Counts vector
53 M += ProfRecord.Counts.size() * sizeof(uint64_t);
56 M += ValueProfData::getSize(ProfileData.second);
58 LE.write<offset_type>(M);
60 return std::make_pair(N, M);
63 static void EmitKey(raw_ostream &Out, key_type_ref K, offset_type N){
64 Out.write(K.data(), N);
67 static void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V,
69 using namespace llvm::support;
70 endian::Writer<little> LE(Out);
71 for (const auto &ProfileData : *V) {
72 const InstrProfRecord &ProfRecord = ProfileData.second;
74 LE.write<uint64_t>(ProfileData.first); // Function hash
75 LE.write<uint64_t>(ProfRecord.Counts.size());
76 for (uint64_t I : ProfRecord.Counts)
77 LE.write<uint64_t>(I);
80 std::unique_ptr<ValueProfData> VDataPtr =
81 ValueProfData::serializeFrom(ProfileData.second);
82 uint32_t S = VDataPtr->getSize();
83 VDataPtr->swapBytesFromHost(ValueProfDataEndianness);
84 Out.write((const char *)VDataPtr.get(), S);
90 // Internal interface for testing purpose only.
91 void InstrProfWriter::setValueProfDataEndianness(
92 support::endianness Endianness) {
93 ValueProfDataEndianness = Endianness;
96 void InstrProfWriter::updateStringTableReferences(InstrProfRecord &I) {
97 I.updateStrings(&StringTable);
100 std::error_code InstrProfWriter::addRecord(InstrProfRecord &&I) {
101 updateStringTableReferences(I);
102 auto &ProfileDataMap = FunctionData[I.Name];
105 ProfilingData::iterator Where;
106 std::tie(Where, NewFunc) =
107 ProfileDataMap.insert(std::make_pair(I.Hash, InstrProfRecord()));
108 InstrProfRecord &Dest = Where->second;
110 // We've never seen a function with this name and hash, add it.
113 // We're updating a function we've seen before.
114 instrprof_error MergeResult = Dest.merge(I);
115 if (MergeResult != instrprof_error::success) {
120 // We keep track of the max function count as we go for simplicity.
121 if (Dest.Counts[0] > MaxFunctionCount)
122 MaxFunctionCount = Dest.Counts[0];
124 return instrprof_error::success;
127 std::pair<uint64_t, uint64_t> InstrProfWriter::writeImpl(raw_ostream &OS) {
128 OnDiskChainedHashTableGenerator<InstrProfRecordTrait> Generator;
130 // Populate the hash table generator.
131 for (const auto &I : FunctionData)
132 Generator.insert(I.getKey(), &I.getValue());
134 using namespace llvm::support;
135 endian::Writer<little> LE(OS);
138 IndexedInstrProf::Header Header;
139 Header.Magic = IndexedInstrProf::Magic;
140 Header.Version = IndexedInstrProf::Version;
141 Header.MaxFunctionCount = MaxFunctionCount;
142 Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
143 Header.HashOffset = 0;
144 int N = sizeof(IndexedInstrProf::Header) / sizeof(uint64_t);
146 // Only write out all the fields execpt 'HashOffset'. We need
147 // to remember the offset of that field to allow back patching
149 for (int I = 0; I < N - 1; I++)
150 LE.write<uint64_t>(reinterpret_cast<uint64_t *>(&Header)[I]);
152 // Save a space to write the hash table start location.
153 uint64_t HashTableStartLoc = OS.tell();
154 // Reserve the space for HashOffset field.
155 LE.write<uint64_t>(0);
156 // Write the hash table.
157 uint64_t HashTableStart = Generator.Emit(OS);
159 return std::make_pair(HashTableStartLoc, HashTableStart);
162 void InstrProfWriter::write(raw_fd_ostream &OS) {
163 // Write the hash table.
164 auto TableStart = writeImpl(OS);
166 // Go back and fill in the hash table start.
167 using namespace support;
168 OS.seek(TableStart.first);
169 // Now patch the HashOffset field previously reserved.
170 endian::Writer<little>(OS).write<uint64_t>(TableStart.second);
173 std::unique_ptr<MemoryBuffer> InstrProfWriter::writeBuffer() {
175 llvm::raw_string_ostream OS(Data);
176 // Write the hash table.
177 auto TableStart = writeImpl(OS);
180 // Go back and fill in the hash table start.
181 using namespace support;
182 uint64_t Bytes = endian::byte_swap<uint64_t, little>(TableStart.second);
183 Data.replace(TableStart.first, sizeof(uint64_t), (const char *)&Bytes,
186 // Return this in an aligned memory buffer.
187 return MemoryBuffer::getMemBufferCopy(Data);