1 //===- SampleProfWriter.cpp - Write LLVM sample profile data --------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the class that writes LLVM sample profiles. It
11 // supports two file formats: text and binary. The textual representation
12 // is useful for debugging and testing purposes. The binary representation
13 // is more compact, resulting in smaller file sizes. However, they can
14 // both be used interchangeably.
15 //
16 // See lib/ProfileData/SampleProfReader.cpp for documentation on each of the
17 // supported formats.
18 //
19 //===----------------------------------------------------------------------===//
20
21 #include "llvm/ProfileData/SampleProfWriter.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/ErrorOr.h"
24 #include "llvm/Support/LEB128.h"
25 #include "llvm/Support/LineIterator.h"
26 #include "llvm/Support/MemoryBuffer.h"
27 #include "llvm/Support/Regex.h"
28
29 using namespace llvm::sampleprof;
30 using namespace llvm;
31
32 /// \brief Write samples to a text file.
33 ///
34 /// Note: it may be tempting to implement this in terms of
35 /// FunctionSamples::print(). Please don't. The dump functionality is intended
36 /// for debugging and has no specified form.
37 ///
38 /// The format used here is more structured and deliberate because
39 /// it needs to be parsed by the SampleProfileReaderText class.
write(const FunctionSamples & S)40 std::error_code SampleProfileWriterText::write(const FunctionSamples &S) {
41 auto &OS = *OutputStream;
42 OS << S.getName() << ":" << S.getTotalSamples();
43 if (Indent == 0)
44 OS << ":" << S.getHeadSamples();
45 OS << "\n";
46
47 SampleSorter<LineLocation, SampleRecord> SortedSamples(S.getBodySamples());
48 for (const auto &I : SortedSamples.get()) {
49 LineLocation Loc = I->first;
50 const SampleRecord &Sample = I->second;
51 OS.indent(Indent + 1);
52 if (Loc.Discriminator == 0)
53 OS << Loc.LineOffset << ": ";
54 else
55 OS << Loc.LineOffset << "." << Loc.Discriminator << ": ";
56
57 OS << Sample.getSamples();
58
59 for (const auto &J : Sample.getCallTargets())
60 OS << " " << J.first() << ":" << J.second;
61 OS << "\n";
62 }
63
64 SampleSorter<LineLocation, FunctionSamples> SortedCallsiteSamples(
65 S.getCallsiteSamples());
66 Indent += 1;
67 for (const auto &I : SortedCallsiteSamples.get()) {
68 LineLocation Loc = I->first;
69 const FunctionSamples &CalleeSamples = I->second;
70 OS.indent(Indent);
71 if (Loc.Discriminator == 0)
72 OS << Loc.LineOffset << ": ";
73 else
74 OS << Loc.LineOffset << "." << Loc.Discriminator << ": ";
75 if (std::error_code EC = write(CalleeSamples))
76 return EC;
77 }
78 Indent -= 1;
79
80 return sampleprof_error::success;
81 }
82
writeNameIdx(StringRef FName)83 std::error_code SampleProfileWriterBinary::writeNameIdx(StringRef FName) {
84 const auto &ret = NameTable.find(FName);
85 if (ret == NameTable.end())
86 return sampleprof_error::truncated_name_table;
87 encodeULEB128(ret->second, *OutputStream);
88 return sampleprof_error::success;
89 }
90
addName(StringRef FName)91 void SampleProfileWriterBinary::addName(StringRef FName) {
92 auto NextIdx = NameTable.size();
93 NameTable.insert(std::make_pair(FName, NextIdx));
94 }
95
addNames(const FunctionSamples & S)96 void SampleProfileWriterBinary::addNames(const FunctionSamples &S) {
97 // Add all the names in indirect call targets.
98 for (const auto &I : S.getBodySamples()) {
99 const SampleRecord &Sample = I.second;
100 for (const auto &J : Sample.getCallTargets())
101 addName(J.first());
102 }
103
104 // Recursively add all the names for inlined callsites.
105 for (const auto &J : S.getCallsiteSamples()) {
106 const FunctionSamples &CalleeSamples = J.second;
107 addName(CalleeSamples.getName());
108 addNames(CalleeSamples);
109 }
110 }
111
writeHeader(const StringMap<FunctionSamples> & ProfileMap)112 std::error_code SampleProfileWriterBinary::writeHeader(
113 const StringMap<FunctionSamples> &ProfileMap) {
114 auto &OS = *OutputStream;
115
116 // Write file magic identifier.
117 encodeULEB128(SPMagic(), OS);
118 encodeULEB128(SPVersion(), OS);
119
120 computeSummary(ProfileMap);
121 if (auto EC = writeSummary())
122 return EC;
123
124 // Generate the name table for all the functions referenced in the profile.
125 for (const auto &I : ProfileMap) {
126 addName(I.first());
127 addNames(I.second);
128 }
129
130 // Write out the name table.
131 encodeULEB128(NameTable.size(), OS);
132 for (auto N : NameTable) {
133 OS << N.first;
134 encodeULEB128(0, OS);
135 }
136 return sampleprof_error::success;
137 }
138
writeSummary()139 std::error_code SampleProfileWriterBinary::writeSummary() {
140 auto &OS = *OutputStream;
141 encodeULEB128(Summary->getTotalCount(), OS);
142 encodeULEB128(Summary->getMaxCount(), OS);
143 encodeULEB128(Summary->getMaxFunctionCount(), OS);
144 encodeULEB128(Summary->getNumCounts(), OS);
145 encodeULEB128(Summary->getNumFunctions(), OS);
146 std::vector<ProfileSummaryEntry> &Entries = Summary->getDetailedSummary();
147 encodeULEB128(Entries.size(), OS);
148 for (auto Entry : Entries) {
149 encodeULEB128(Entry.Cutoff, OS);
150 encodeULEB128(Entry.MinCount, OS);
151 encodeULEB128(Entry.NumCounts, OS);
152 }
153 return sampleprof_error::success;
154 }
writeBody(const FunctionSamples & S)155 std::error_code SampleProfileWriterBinary::writeBody(const FunctionSamples &S) {
156 auto &OS = *OutputStream;
157
158 if (std::error_code EC = writeNameIdx(S.getName()))
159 return EC;
160
161 encodeULEB128(S.getTotalSamples(), OS);
162
163 // Emit all the body samples.
164 encodeULEB128(S.getBodySamples().size(), OS);
165 for (const auto &I : S.getBodySamples()) {
166 LineLocation Loc = I.first;
167 const SampleRecord &Sample = I.second;
168 encodeULEB128(Loc.LineOffset, OS);
169 encodeULEB128(Loc.Discriminator, OS);
170 encodeULEB128(Sample.getSamples(), OS);
171 encodeULEB128(Sample.getCallTargets().size(), OS);
172 for (const auto &J : Sample.getCallTargets()) {
173 StringRef Callee = J.first();
174 uint64_t CalleeSamples = J.second;
175 if (std::error_code EC = writeNameIdx(Callee))
176 return EC;
177 encodeULEB128(CalleeSamples, OS);
178 }
179 }
180
181 // Recursively emit all the callsite samples.
182 encodeULEB128(S.getCallsiteSamples().size(), OS);
183 for (const auto &J : S.getCallsiteSamples()) {
184 LineLocation Loc = J.first;
185 const FunctionSamples &CalleeSamples = J.second;
186 encodeULEB128(Loc.LineOffset, OS);
187 encodeULEB128(Loc.Discriminator, OS);
188 if (std::error_code EC = writeBody(CalleeSamples))
189 return EC;
190 }
191
192 return sampleprof_error::success;
193 }
194
195 /// \brief Write samples of a top-level function to a binary file.
196 ///
197 /// \returns true if the samples were written successfully, false otherwise.
write(const FunctionSamples & S)198 std::error_code SampleProfileWriterBinary::write(const FunctionSamples &S) {
199 encodeULEB128(S.getHeadSamples(), *OutputStream);
200 return writeBody(S);
201 }
202
203 /// \brief Create a sample profile file writer based on the specified format.
204 ///
205 /// \param Filename The file to create.
206 ///
207 /// \param Writer The writer to instantiate according to the specified format.
208 ///
209 /// \param Format Encoding format for the profile file.
210 ///
211 /// \returns an error code indicating the status of the created writer.
212 ErrorOr<std::unique_ptr<SampleProfileWriter>>
create(StringRef Filename,SampleProfileFormat Format)213 SampleProfileWriter::create(StringRef Filename, SampleProfileFormat Format) {
214 std::error_code EC;
215 std::unique_ptr<raw_ostream> OS;
216 if (Format == SPF_Binary)
217 OS.reset(new raw_fd_ostream(Filename, EC, sys::fs::F_None));
218 else
219 OS.reset(new raw_fd_ostream(Filename, EC, sys::fs::F_Text));
220 if (EC)
221 return EC;
222
223 return create(OS, Format);
224 }
225
226 /// \brief Create a sample profile stream writer based on the specified format.
227 ///
228 /// \param OS The output stream to store the profile data to.
229 ///
230 /// \param Writer The writer to instantiate according to the specified format.
231 ///
232 /// \param Format Encoding format for the profile file.
233 ///
234 /// \returns an error code indicating the status of the created writer.
235 ErrorOr<std::unique_ptr<SampleProfileWriter>>
create(std::unique_ptr<raw_ostream> & OS,SampleProfileFormat Format)236 SampleProfileWriter::create(std::unique_ptr<raw_ostream> &OS,
237 SampleProfileFormat Format) {
238 std::error_code EC;
239 std::unique_ptr<SampleProfileWriter> Writer;
240
241 if (Format == SPF_Binary)
242 Writer.reset(new SampleProfileWriterBinary(OS));
243 else if (Format == SPF_Text)
244 Writer.reset(new SampleProfileWriterText(OS));
245 else if (Format == SPF_GCC)
246 EC = sampleprof_error::unsupported_writing_format;
247 else
248 EC = sampleprof_error::unrecognized_format;
249
250 if (EC)
251 return EC;
252
253 return std::move(Writer);
254 }
255
computeSummary(const StringMap<FunctionSamples> & ProfileMap)256 void SampleProfileWriter::computeSummary(
257 const StringMap<FunctionSamples> &ProfileMap) {
258 SampleProfileSummaryBuilder Builder(ProfileSummaryBuilder::DefaultCutoffs);
259 for (const auto &I : ProfileMap) {
260 const FunctionSamples &Profile = I.second;
261 Builder.addRecord(Profile);
262 }
263 Summary = Builder.getSummary();
264 }
265