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 std::error_code SampleProfileWriterText::write(StringRef FName,
34                                                const FunctionSamples &S) {
35   OS << FName << ":" << S.getTotalSamples();
36   if (Indent == 0)
37     OS << ":" << S.getHeadSamples();
38   OS << "\n";
39 
40   for (const auto &I : S.getBodySamples()) {
41     LineLocation Loc = I.first;
42     const SampleRecord &Sample = I.second;
43     OS.indent(Indent + 1);
44     if (Loc.Discriminator == 0)
45       OS << Loc.LineOffset << ": ";
46     else
47       OS << Loc.LineOffset << "." << Loc.Discriminator << ": ";
48 
49     OS << Sample.getSamples();
50 
51     for (const auto &J : Sample.getCallTargets())
52       OS << " " << J.first() << ":" << J.second;
53     OS << "\n";
54   }
55 
56   Indent += 1;
57   for (const auto &I : S.getCallsiteSamples()) {
58     CallsiteLocation Loc = I.first;
59     const FunctionSamples &CalleeSamples = I.second;
60     OS.indent(Indent);
61     if (Loc.Discriminator == 0)
62       OS << Loc.LineOffset << ": ";
63     else
64       OS << Loc.LineOffset << "." << Loc.Discriminator << ": ";
65     if (std::error_code EC = write(Loc.CalleeName, CalleeSamples))
66       return EC;
67   }
68   Indent -= 1;
69 
70   return sampleprof_error::success;
71 }
72 
73 std::error_code SampleProfileWriterBinary::writeNameIdx(StringRef FName) {
74   const auto &ret = NameTable.find(FName);
75   if (ret == NameTable.end())
76     return sampleprof_error::truncated_name_table;
77   encodeULEB128(ret->second, OS);
78   return sampleprof_error::success;
79 }
80 
81 void SampleProfileWriterBinary::addName(StringRef FName) {
82   auto NextIdx = NameTable.size();
83   NameTable.insert(std::make_pair(FName, NextIdx));
84 }
85 
86 void SampleProfileWriterBinary::addNames(const FunctionSamples &S) {
87   // Add all the names in indirect call targets.
88   for (const auto &I : S.getBodySamples()) {
89     const SampleRecord &Sample = I.second;
90     for (const auto &J : Sample.getCallTargets())
91       addName(J.first());
92   }
93 
94   // Recursively add all the names for inlined callsites.
95   for (const auto &J : S.getCallsiteSamples()) {
96     CallsiteLocation Loc = J.first;
97     const FunctionSamples &CalleeSamples = J.second;
98     addName(Loc.CalleeName);
99     addNames(CalleeSamples);
100   }
101 }
102 
103 std::error_code SampleProfileWriterBinary::writeHeader(
104     const StringMap<FunctionSamples> &ProfileMap) {
105   // Write file magic identifier.
106   encodeULEB128(SPMagic(), OS);
107   encodeULEB128(SPVersion(), OS);
108 
109   // Generate the name table for all the functions referenced in the profile.
110   for (const auto &I : ProfileMap) {
111     addName(I.first());
112     addNames(I.second);
113   }
114 
115   // Write out the name table.
116   encodeULEB128(NameTable.size(), OS);
117   for (auto N : NameTable) {
118     OS << N.first;
119     encodeULEB128(0, OS);
120   }
121 
122   return sampleprof_error::success;
123 }
124 
125 std::error_code SampleProfileWriterBinary::writeBody(StringRef FName,
126                                                      const FunctionSamples &S) {
127   if (std::error_code EC = writeNameIdx(FName))
128     return EC;
129 
130   encodeULEB128(S.getTotalSamples(), OS);
131 
132   // Emit all the body samples.
133   encodeULEB128(S.getBodySamples().size(), OS);
134   for (const auto &I : S.getBodySamples()) {
135     LineLocation Loc = I.first;
136     const SampleRecord &Sample = I.second;
137     encodeULEB128(Loc.LineOffset, OS);
138     encodeULEB128(Loc.Discriminator, OS);
139     encodeULEB128(Sample.getSamples(), OS);
140     encodeULEB128(Sample.getCallTargets().size(), OS);
141     for (const auto &J : Sample.getCallTargets()) {
142       StringRef Callee = J.first();
143       uint64_t CalleeSamples = J.second;
144       if (std::error_code EC = writeNameIdx(Callee))
145         return EC;
146       encodeULEB128(CalleeSamples, OS);
147     }
148   }
149 
150   // Recursively emit all the callsite samples.
151   encodeULEB128(S.getCallsiteSamples().size(), OS);
152   for (const auto &J : S.getCallsiteSamples()) {
153     CallsiteLocation Loc = J.first;
154     const FunctionSamples &CalleeSamples = J.second;
155     encodeULEB128(Loc.LineOffset, OS);
156     encodeULEB128(Loc.Discriminator, OS);
157     if (std::error_code EC = writeBody(Loc.CalleeName, CalleeSamples))
158       return EC;
159   }
160 
161   return sampleprof_error::success;
162 }
163 
164 /// \brief Write samples of a top-level function to a binary file.
165 ///
166 /// \returns true if the samples were written successfully, false otherwise.
167 std::error_code SampleProfileWriterBinary::write(StringRef FName,
168                                                  const FunctionSamples &S) {
169   encodeULEB128(S.getHeadSamples(), OS);
170   return writeBody(FName, S);
171 }
172 
173 /// \brief Create a sample profile writer based on the specified format.
174 ///
175 /// \param Filename The file to create.
176 ///
177 /// \param Writer The writer to instantiate according to the specified format.
178 ///
179 /// \param Format Encoding format for the profile file.
180 ///
181 /// \returns an error code indicating the status of the created writer.
182 ErrorOr<std::unique_ptr<SampleProfileWriter>>
183 SampleProfileWriter::create(StringRef Filename, SampleProfileFormat Format) {
184   std::error_code EC;
185   std::unique_ptr<SampleProfileWriter> Writer;
186 
187   if (Format == SPF_Binary)
188     Writer.reset(new SampleProfileWriterBinary(Filename, EC));
189   else if (Format == SPF_Text)
190     Writer.reset(new SampleProfileWriterText(Filename, EC));
191   else if (Format == SPF_GCC)
192     EC = sampleprof_error::unsupported_writing_format;
193   else
194     EC = sampleprof_error::unrecognized_format;
195 
196   if (EC)
197     return EC;
198 
199   return std::move(Writer);
200 }
201