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.
40 std::error_code SampleProfileWriterText::write(StringRef FName,
41                                                const FunctionSamples &S) {
42   auto &OS = *OutputStream;
43 
44   OS << FName << ":" << S.getTotalSamples();
45   if (Indent == 0)
46     OS << ":" << S.getHeadSamples();
47   OS << "\n";
48 
49   SampleSorter<LineLocation, SampleRecord> SortedSamples(S.getBodySamples());
50   for (const auto &I : SortedSamples.get()) {
51     LineLocation Loc = I->first;
52     const SampleRecord &Sample = I->second;
53     OS.indent(Indent + 1);
54     if (Loc.Discriminator == 0)
55       OS << Loc.LineOffset << ": ";
56     else
57       OS << Loc.LineOffset << "." << Loc.Discriminator << ": ";
58 
59     OS << Sample.getSamples();
60 
61     for (const auto &J : Sample.getCallTargets())
62       OS << " " << J.first() << ":" << J.second;
63     OS << "\n";
64   }
65 
66   SampleSorter<CallsiteLocation, FunctionSamples> SortedCallsiteSamples(
67       S.getCallsiteSamples());
68   Indent += 1;
69   for (const auto &I : SortedCallsiteSamples.get()) {
70     CallsiteLocation Loc = I->first;
71     const FunctionSamples &CalleeSamples = I->second;
72     OS.indent(Indent);
73     if (Loc.Discriminator == 0)
74       OS << Loc.LineOffset << ": ";
75     else
76       OS << Loc.LineOffset << "." << Loc.Discriminator << ": ";
77     if (std::error_code EC = write(Loc.CalleeName, CalleeSamples))
78       return EC;
79   }
80   Indent -= 1;
81 
82   return sampleprof_error::success;
83 }
84 
85 std::error_code SampleProfileWriterBinary::writeNameIdx(StringRef FName) {
86   const auto &ret = NameTable.find(FName);
87   if (ret == NameTable.end())
88     return sampleprof_error::truncated_name_table;
89   encodeULEB128(ret->second, *OutputStream);
90   return sampleprof_error::success;
91 }
92 
93 void SampleProfileWriterBinary::addName(StringRef FName) {
94   auto NextIdx = NameTable.size();
95   NameTable.insert(std::make_pair(FName, NextIdx));
96 }
97 
98 void SampleProfileWriterBinary::addNames(const FunctionSamples &S) {
99   // Add all the names in indirect call targets.
100   for (const auto &I : S.getBodySamples()) {
101     const SampleRecord &Sample = I.second;
102     for (const auto &J : Sample.getCallTargets())
103       addName(J.first());
104   }
105 
106   // Recursively add all the names for inlined callsites.
107   for (const auto &J : S.getCallsiteSamples()) {
108     CallsiteLocation Loc = J.first;
109     const FunctionSamples &CalleeSamples = J.second;
110     addName(Loc.CalleeName);
111     addNames(CalleeSamples);
112   }
113 }
114 
115 std::error_code SampleProfileWriterBinary::writeHeader(
116     const StringMap<FunctionSamples> &ProfileMap) {
117   auto &OS = *OutputStream;
118 
119   // Write file magic identifier.
120   encodeULEB128(SPMagic(), OS);
121   encodeULEB128(SPVersion(), OS);
122 
123   computeSummary(ProfileMap);
124   if (auto EC = writeSummary())
125     return EC;
126 
127   // Generate the name table for all the functions referenced in the profile.
128   for (const auto &I : ProfileMap) {
129     addName(I.first());
130     addNames(I.second);
131   }
132 
133   // Write out the name table.
134   encodeULEB128(NameTable.size(), OS);
135   for (auto N : NameTable) {
136     OS << N.first;
137     encodeULEB128(0, OS);
138   }
139   return sampleprof_error::success;
140 }
141 
142 std::error_code SampleProfileWriterBinary::writeSummary() {
143   auto &OS = *OutputStream;
144   encodeULEB128(Summary->getTotalSamples(), OS);
145   encodeULEB128(Summary->getMaxSamplesPerLine(), OS);
146   encodeULEB128(Summary->getMaxHeadSamples(), OS);
147   encodeULEB128(Summary->getNumLinesWithSamples(), OS);
148   encodeULEB128(Summary->getNumFunctions(), OS);
149   std::vector<ProfileSummaryEntry> &Entries = Summary->getDetailedSummary();
150   encodeULEB128(Entries.size(), OS);
151   for (auto Entry : Entries) {
152     encodeULEB128(Entry.Cutoff, OS);
153     encodeULEB128(Entry.MinCount, OS);
154     encodeULEB128(Entry.NumCounts, OS);
155   }
156   return sampleprof_error::success;
157 }
158 std::error_code SampleProfileWriterBinary::writeBody(StringRef FName,
159                                                      const FunctionSamples &S) {
160   auto &OS = *OutputStream;
161 
162   if (std::error_code EC = writeNameIdx(FName))
163     return EC;
164 
165   encodeULEB128(S.getTotalSamples(), OS);
166 
167   // Emit all the body samples.
168   encodeULEB128(S.getBodySamples().size(), OS);
169   for (const auto &I : S.getBodySamples()) {
170     LineLocation Loc = I.first;
171     const SampleRecord &Sample = I.second;
172     encodeULEB128(Loc.LineOffset, OS);
173     encodeULEB128(Loc.Discriminator, OS);
174     encodeULEB128(Sample.getSamples(), OS);
175     encodeULEB128(Sample.getCallTargets().size(), OS);
176     for (const auto &J : Sample.getCallTargets()) {
177       StringRef Callee = J.first();
178       uint64_t CalleeSamples = J.second;
179       if (std::error_code EC = writeNameIdx(Callee))
180         return EC;
181       encodeULEB128(CalleeSamples, OS);
182     }
183   }
184 
185   // Recursively emit all the callsite samples.
186   encodeULEB128(S.getCallsiteSamples().size(), OS);
187   for (const auto &J : S.getCallsiteSamples()) {
188     CallsiteLocation Loc = J.first;
189     const FunctionSamples &CalleeSamples = J.second;
190     encodeULEB128(Loc.LineOffset, OS);
191     encodeULEB128(Loc.Discriminator, OS);
192     if (std::error_code EC = writeBody(Loc.CalleeName, CalleeSamples))
193       return EC;
194   }
195 
196   return sampleprof_error::success;
197 }
198 
199 /// \brief Write samples of a top-level function to a binary file.
200 ///
201 /// \returns true if the samples were written successfully, false otherwise.
202 std::error_code SampleProfileWriterBinary::write(StringRef FName,
203                                                  const FunctionSamples &S) {
204   encodeULEB128(S.getHeadSamples(), *OutputStream);
205   return writeBody(FName, S);
206 }
207 
208 /// \brief Create a sample profile file writer based on the specified format.
209 ///
210 /// \param Filename The file to create.
211 ///
212 /// \param Writer The writer to instantiate according to the specified format.
213 ///
214 /// \param Format Encoding format for the profile file.
215 ///
216 /// \returns an error code indicating the status of the created writer.
217 ErrorOr<std::unique_ptr<SampleProfileWriter>>
218 SampleProfileWriter::create(StringRef Filename, SampleProfileFormat Format) {
219   std::error_code EC;
220   std::unique_ptr<raw_ostream> OS;
221   if (Format == SPF_Binary)
222     OS.reset(new raw_fd_ostream(Filename, EC, sys::fs::F_None));
223   else
224     OS.reset(new raw_fd_ostream(Filename, EC, sys::fs::F_Text));
225   if (EC)
226     return EC;
227 
228   return create(OS, Format);
229 }
230 
231 /// \brief Create a sample profile stream writer based on the specified format.
232 ///
233 /// \param OS The output stream to store the profile data to.
234 ///
235 /// \param Writer The writer to instantiate according to the specified format.
236 ///
237 /// \param Format Encoding format for the profile file.
238 ///
239 /// \returns an error code indicating the status of the created writer.
240 ErrorOr<std::unique_ptr<SampleProfileWriter>>
241 SampleProfileWriter::create(std::unique_ptr<raw_ostream> &OS,
242                             SampleProfileFormat Format) {
243   std::error_code EC;
244   std::unique_ptr<SampleProfileWriter> Writer;
245 
246   if (Format == SPF_Binary)
247     Writer.reset(new SampleProfileWriterBinary(OS));
248   else if (Format == SPF_Text)
249     Writer.reset(new SampleProfileWriterText(OS));
250   else if (Format == SPF_GCC)
251     EC = sampleprof_error::unsupported_writing_format;
252   else
253     EC = sampleprof_error::unrecognized_format;
254 
255   if (EC)
256     return EC;
257 
258   return std::move(Writer);
259 }
260 
261 void SampleProfileWriter::computeSummary(
262     const StringMap<FunctionSamples> &ProfileMap) {
263   Summary.reset(new SampleProfileSummary(ProfileSummary::DefaultCutoffs));
264   for (const auto &I : ProfileMap) {
265     const FunctionSamples &Profile = I.second;
266     Summary->addRecord(Profile);
267   }
268   Summary->computeDetailedSummary();
269 }
270