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 class InstrProfRecordTrait {
25 typedef StringRef key_type;
26 typedef StringRef key_type_ref;
28 typedef const InstrProfWriter::ProfilingData *const data_type;
29 typedef const InstrProfWriter::ProfilingData *const data_type_ref;
31 typedef uint64_t hash_value_type;
32 typedef uint64_t offset_type;
34 static hash_value_type ComputeHash(key_type_ref K) {
35 return IndexedInstrProf::ComputeHash(IndexedInstrProf::HashType, K);
38 static std::pair<offset_type, offset_type>
39 EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) {
40 using namespace llvm::support;
41 endian::Writer<little> LE(Out);
43 offset_type N = K.size();
44 LE.write<offset_type>(N);
47 for (const auto &ProfileData : *V) {
48 const InstrProfRecord &ProfRecord = ProfileData.second;
49 M += sizeof(uint64_t); // The function hash
50 M += sizeof(uint64_t); // The size of the Counts vector
51 M += ProfRecord.Counts.size() * sizeof(uint64_t);
54 M += sizeof(uint64_t); // Number of value kinds with value sites.
55 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind) {
56 uint32_t NumValueSites = ProfRecord.getNumValueSites(Kind);
57 if (NumValueSites == 0)
59 M += sizeof(uint64_t); // Value kind
60 M += sizeof(uint64_t); // The number of value sites for given value kind
61 for (uint32_t I = 0; I < NumValueSites; I++) {
62 M += sizeof(uint64_t); // Number of value data pairs at a value site
63 uint64_t NumValueDataForSite =
64 ProfRecord.getNumValueDataForSite(Kind, I);
65 M += 2 * sizeof(uint64_t) * NumValueDataForSite; // Value data pairs
69 LE.write<offset_type>(M);
71 return std::make_pair(N, M);
74 static void EmitKey(raw_ostream &Out, key_type_ref K, offset_type N){
75 Out.write(K.data(), N);
78 static void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V,
80 using namespace llvm::support;
81 endian::Writer<little> LE(Out);
82 for (const auto &ProfileData : *V) {
83 const InstrProfRecord &ProfRecord = ProfileData.second;
85 LE.write<uint64_t>(ProfileData.first); // Function hash
86 LE.write<uint64_t>(ProfRecord.Counts.size());
87 for (uint64_t I : ProfRecord.Counts)
88 LE.write<uint64_t>(I);
90 // Compute the number of value kinds with value sites.
91 uint64_t NumValueKinds = ProfRecord.getNumValueKinds();
92 LE.write<uint64_t>(NumValueKinds);
95 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind) {
96 uint32_t NumValueSites = ProfRecord.getNumValueSites(Kind);
97 if (NumValueSites == 0)
99 LE.write<uint64_t>(Kind); // Write value kind
100 // Write number of value sites for current value kind
101 LE.write<uint64_t>(NumValueSites);
103 for (uint32_t I = 0; I < NumValueSites; I++) {
104 // Write number of value data pairs at this value site
105 uint64_t NumValueDataForSite =
106 ProfRecord.getNumValueDataForSite(Kind, I);
107 LE.write<uint64_t>(NumValueDataForSite);
108 std::unique_ptr<InstrProfValueData[]> VD =
109 ProfRecord.getValueForSite(Kind, I);
111 for (uint32_t V = 0; V < NumValueDataForSite; V++) {
112 if (Kind == IPVK_IndirectCallTarget)
113 LE.write<uint64_t>(ComputeHash((const char *)VD[V].Value));
115 LE.write<uint64_t>(VD[V].Value);
116 LE.write<uint64_t>(VD[V].Count);
125 static std::error_code combineInstrProfRecords(InstrProfRecord &Dest,
126 InstrProfRecord &Source,
127 uint64_t &MaxFunctionCount) {
128 // If the number of counters doesn't match we either have bad data
129 // or a hash collision.
130 if (Dest.Counts.size() != Source.Counts.size())
131 return instrprof_error::count_mismatch;
133 for (size_t I = 0, E = Source.Counts.size(); I < E; ++I) {
134 if (Dest.Counts[I] + Source.Counts[I] < Dest.Counts[I])
135 return instrprof_error::counter_overflow;
136 Dest.Counts[I] += Source.Counts[I];
139 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind) {
140 if (std::error_code EC = Dest.mergeValueProfData(Kind, Source))
144 // We keep track of the max function count as we go for simplicity.
145 if (Dest.Counts[0] > MaxFunctionCount)
146 MaxFunctionCount = Dest.Counts[0];
148 return instrprof_error::success;
151 void InstrProfWriter::updateStringTableReferences(InstrProfRecord &I) {
152 I.updateStrings(&StringTable);
155 std::error_code InstrProfWriter::addRecord(InstrProfRecord &&I) {
156 updateStringTableReferences(I);
157 auto &ProfileDataMap = FunctionData[I.Name];
159 auto Where = ProfileDataMap.find(I.Hash);
160 if (Where == ProfileDataMap.end()) {
161 // We've never seen a function with this name and hash, add it.
162 ProfileDataMap[I.Hash] = I;
164 // We keep track of the max function count as we go for simplicity.
165 if (I.Counts[0] > MaxFunctionCount)
166 MaxFunctionCount = I.Counts[0];
167 return instrprof_error::success;
170 // We're updating a function we've seen before.
171 return combineInstrProfRecords(Where->second, I, MaxFunctionCount);
174 std::pair<uint64_t, uint64_t> InstrProfWriter::writeImpl(raw_ostream &OS) {
175 OnDiskChainedHashTableGenerator<InstrProfRecordTrait> Generator;
177 // Populate the hash table generator.
178 for (const auto &I : FunctionData)
179 Generator.insert(I.getKey(), &I.getValue());
181 using namespace llvm::support;
182 endian::Writer<little> LE(OS);
185 IndexedInstrProf::Header Header;
186 Header.Magic = IndexedInstrProf::Magic;
187 Header.Version = IndexedInstrProf::Version;
188 Header.MaxFunctionCount = MaxFunctionCount;
189 Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
190 Header.HashOffset = 0;
191 int N = sizeof(IndexedInstrProf::Header) / sizeof(uint64_t);
193 // Only write out all the fields execpt 'HashOffset'. We need
194 // to remember the offset of that field to allow back patching
196 for (int I = 0; I < N - 1; I++)
197 LE.write<uint64_t>(reinterpret_cast<uint64_t *>(&Header)[I]);
199 // Save a space to write the hash table start location.
200 uint64_t HashTableStartLoc = OS.tell();
201 // Reserve the space for HashOffset field.
202 LE.write<uint64_t>(0);
203 // Write the hash table.
204 uint64_t HashTableStart = Generator.Emit(OS);
206 return std::make_pair(HashTableStartLoc, HashTableStart);
209 void InstrProfWriter::write(raw_fd_ostream &OS) {
210 // Write the hash table.
211 auto TableStart = writeImpl(OS);
213 // Go back and fill in the hash table start.
214 using namespace support;
215 OS.seek(TableStart.first);
216 // Now patch the HashOffset field previously reserved.
217 endian::Writer<little>(OS).write<uint64_t>(TableStart.second);
220 std::unique_ptr<MemoryBuffer> InstrProfWriter::writeBuffer() {
222 llvm::raw_string_ostream OS(Data);
223 // Write the hash table.
224 auto TableStart = writeImpl(OS);
227 // Go back and fill in the hash table start.
228 using namespace support;
229 uint64_t Bytes = endian::byte_swap<uint64_t, little>(TableStart.second);
230 Data.replace(TableStart.first, sizeof(uint64_t), (const char *)&Bytes,
233 // Return this in an aligned memory buffer.
234 return MemoryBuffer::getMemBufferCopy(Data);