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.
write(StringRef FName,const FunctionSamples & S)33 bool SampleProfileWriterText::write(StringRef FName, const FunctionSamples &S) {
34   if (S.empty())
35     return true;
36 
37   OS << FName << ":" << S.getTotalSamples() << ":" << S.getHeadSamples()
38      << "\n";
39 
40   for (const auto &I : S.getBodySamples()) {
41     LineLocation Loc = I.first;
42     const SampleRecord &Sample = I.second;
43     if (Loc.Discriminator == 0)
44       OS << Loc.LineOffset << ": ";
45     else
46       OS << Loc.LineOffset << "." << Loc.Discriminator << ": ";
47 
48     OS << Sample.getSamples();
49 
50     for (const auto &J : Sample.getCallTargets())
51       OS << " " << J.first() << ":" << J.second;
52     OS << "\n";
53   }
54 
55   return true;
56 }
57 
SampleProfileWriterBinary(StringRef F,std::error_code & EC)58 SampleProfileWriterBinary::SampleProfileWriterBinary(StringRef F,
59                                                      std::error_code &EC)
60     : SampleProfileWriter(F, EC, sys::fs::F_None) {
61   if (EC)
62     return;
63 
64   // Write the file header.
65   encodeULEB128(SPMagic(), OS);
66   encodeULEB128(SPVersion(), OS);
67 }
68 
69 /// \brief Write samples to a binary file.
70 ///
71 /// \returns true if the samples were written successfully, false otherwise.
write(StringRef FName,const FunctionSamples & S)72 bool SampleProfileWriterBinary::write(StringRef FName,
73                                       const FunctionSamples &S) {
74   if (S.empty())
75     return true;
76 
77   OS << FName;
78   encodeULEB128(0, OS);
79   encodeULEB128(S.getTotalSamples(), OS);
80   encodeULEB128(S.getHeadSamples(), OS);
81   encodeULEB128(S.getBodySamples().size(), OS);
82   for (const auto &I : S.getBodySamples()) {
83     LineLocation Loc = I.first;
84     const SampleRecord &Sample = I.second;
85     encodeULEB128(Loc.LineOffset, OS);
86     encodeULEB128(Loc.Discriminator, OS);
87     encodeULEB128(Sample.getSamples(), OS);
88     encodeULEB128(Sample.getCallTargets().size(), OS);
89     for (const auto &J : Sample.getCallTargets()) {
90       std::string Callee = J.first();
91       unsigned CalleeSamples = J.second;
92       OS << Callee;
93       encodeULEB128(0, OS);
94       encodeULEB128(CalleeSamples, OS);
95     }
96   }
97 
98   return true;
99 }
100 
101 /// \brief Create a sample profile writer based on the specified format.
102 ///
103 /// \param Filename The file to create.
104 ///
105 /// \param Writer The writer to instantiate according to the specified format.
106 ///
107 /// \param Format Encoding format for the profile file.
108 ///
109 /// \returns an error code indicating the status of the created writer.
110 ErrorOr<std::unique_ptr<SampleProfileWriter>>
create(StringRef Filename,SampleProfileFormat Format)111 SampleProfileWriter::create(StringRef Filename, SampleProfileFormat Format) {
112   std::error_code EC;
113   std::unique_ptr<SampleProfileWriter> Writer;
114 
115   if (Format == SPF_Binary)
116     Writer.reset(new SampleProfileWriterBinary(Filename, EC));
117   else if (Format == SPF_Text)
118     Writer.reset(new SampleProfileWriterText(Filename, EC));
119   else
120     EC = sampleprof_error::unrecognized_format;
121 
122   if (EC)
123     return EC;
124 
125   return std::move(Writer);
126 }
127