include/llvm/ProfileData/SampleProfWriter.h

   1 //===- SampleProfWriter.h - Write LLVM sample profile data ------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file contains definitions needed for writing sample profiles.
  10 //
  11 //===----------------------------------------------------------------------===//
  12 #ifndef LLVM_PROFILEDATA_SAMPLEPROFWRITER_H
  13 #define LLVM_PROFILEDATA_SAMPLEPROFWRITER_H
  14
  15 #include "llvm/ADT/MapVector.h"
  16 #include "llvm/ADT/StringMap.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/IR/ProfileSummary.h"
  19 #include "llvm/ProfileData/SampleProf.h"
  20 #include "llvm/Support/ErrorOr.h"
  21 #include "llvm/Support/raw_ostream.h"
  22 #include <algorithm>
  23 #include <cstdint>
  24 #include <memory>
  25 #include <set>
  26 #include <system_error>
  27
  28 namespace llvm {
  29 namespace sampleprof {
  30
  31 /// Sample-based profile writer. Base class.
  32 class SampleProfileWriter {
  33 public:
  34   virtual ~SampleProfileWriter() = default;
  35
  36   /// Write sample profiles in \p S.
  37   ///
  38   /// \returns status code of the file update operation.
  39   virtual std::error_code writeSample(const FunctionSamples &S) = 0;
  40
  41   /// Write all the sample profiles in the given map of samples.
  42   ///
  43   /// \returns status code of the file update operation.
  44   virtual std::error_code write(const StringMap<FunctionSamples> &ProfileMap);
  45
  46   raw_ostream &getOutputStream() { return *OutputStream; }
  47
  48   /// Profile writer factory.
  49   ///
  50   /// Create a new file writer based on the value of \p Format.
  51   static ErrorOr<std::unique_ptr<SampleProfileWriter>>
  52   create(StringRef Filename, SampleProfileFormat Format);
  53
  54   /// Create a new stream writer based on the value of \p Format.
  55   /// For testing.
  56   static ErrorOr<std::unique_ptr<SampleProfileWriter>>
  57   create(std::unique_ptr<raw_ostream> &OS, SampleProfileFormat Format);
  58
  59   virtual void setProfileSymbolList(ProfileSymbolList *PSL) {}
  60
  61 protected:
  62   SampleProfileWriter(std::unique_ptr<raw_ostream> &OS)
  63       : OutputStream(std::move(OS)) {}
  64
  65   /// Write a file header for the profile file.
  66   virtual std::error_code
  67   writeHeader(const StringMap<FunctionSamples> &ProfileMap) = 0;
  68
  69   // Write function profiles to the profile file.
  70   virtual std::error_code
  71   writeFuncProfiles(const StringMap<FunctionSamples> &ProfileMap);
  72
  73   /// Output stream where to emit the profile to.
  74   std::unique_ptr<raw_ostream> OutputStream;
  75
  76   /// Profile summary.
  77   std::unique_ptr<ProfileSummary> Summary;
  78
  79   /// Compute summary for this profile.
  80   void computeSummary(const StringMap<FunctionSamples> &ProfileMap);
  81
  82   /// Profile format.
  83   SampleProfileFormat Format;
  84 };
  85
  86 /// Sample-based profile writer (text format).
  87 class SampleProfileWriterText : public SampleProfileWriter {
  88 public:
  89   std::error_code writeSample(const FunctionSamples &S) override;
  90
  91 protected:
  92   SampleProfileWriterText(std::unique_ptr<raw_ostream> &OS)
  93       : SampleProfileWriter(OS), Indent(0) {}
  94
  95   std::error_code
  96   writeHeader(const StringMap<FunctionSamples> &ProfileMap) override {
  97     return sampleprof_error::success;
  98   }
  99
 100 private:
 101   /// Indent level to use when writing.
 102   ///
 103   /// This is used when printing inlined callees.
 104   unsigned Indent;
 105
 106   friend ErrorOr<std::unique_ptr<SampleProfileWriter>>
 107   SampleProfileWriter::create(std::unique_ptr<raw_ostream> &OS,
 108                               SampleProfileFormat Format);
 109 };
 110
 111 /// Sample-based profile writer (binary format).
 112 class SampleProfileWriterBinary : public SampleProfileWriter {
 113 public:
 114   SampleProfileWriterBinary(std::unique_ptr<raw_ostream> &OS)
 115       : SampleProfileWriter(OS) {}
 116
 117   virtual std::error_code writeSample(const FunctionSamples &S) override;
 118
 119 protected:
 120   virtual std::error_code writeMagicIdent(SampleProfileFormat Format);
 121   virtual std::error_code writeNameTable();
 122   virtual std::error_code
 123   writeHeader(const StringMap<FunctionSamples> &ProfileMap) override;
 124   std::error_code writeSummary();
 125   std::error_code writeNameIdx(StringRef FName);
 126   std::error_code writeBody(const FunctionSamples &S);
 127   inline void stablizeNameTable(std::set<StringRef> &V);
 128
 129   MapVector<StringRef, uint32_t> NameTable;
 130
 131   void addName(StringRef FName);
 132   void addNames(const FunctionSamples &S);
 133
 134 private:
 135   friend ErrorOr<std::unique_ptr<SampleProfileWriter>>
 136   SampleProfileWriter::create(std::unique_ptr<raw_ostream> &OS,
 137                               SampleProfileFormat Format);
 138 };
 139
 140 class SampleProfileWriterRawBinary : public SampleProfileWriterBinary {
 141   using SampleProfileWriterBinary::SampleProfileWriterBinary;
 142 };
 143
 144 class SampleProfileWriterExtBinaryBase : public SampleProfileWriterBinary {
 145   using SampleProfileWriterBinary::SampleProfileWriterBinary;
 146
 147 public:
 148   virtual std::error_code
 149   write(const StringMap<FunctionSamples> &ProfileMap) override;
 150
 151 protected:
 152   uint64_t markSectionStart();
 153   uint64_t addNewSection(SecType Sec, uint64_t SectionStart);
 154   virtual void initSectionLayout() = 0;
 155   virtual std::error_code
 156   writeSections(const StringMap<FunctionSamples> &ProfileMap) = 0;
 157
 158   // Specifiy the section layout in the profile. Note that the order in
 159   // SecHdrTable (order to collect sections) may be different from the
 160   // order in SectionLayout (order to write out sections into profile).
 161   SmallVector<SecType, 8> SectionLayout;
 162
 163 private:
 164   void allocSecHdrTable();
 165   std::error_code writeSecHdrTable();
 166   virtual std::error_code
 167   writeHeader(const StringMap<FunctionSamples> &ProfileMap) override;
 168
 169   // The location where the output stream starts.
 170   uint64_t FileStart;
 171   // The location in the output stream where the SecHdrTable should be
 172   // written to.
 173   uint64_t SecHdrTableOffset;
 174   std::vector<SecHdrTableEntry> SecHdrTable;
 175 };
 176
 177 class SampleProfileWriterExtBinary : public SampleProfileWriterExtBinaryBase {
 178   using SampleProfileWriterExtBinaryBase::SampleProfileWriterExtBinaryBase;
 179
 180 public:
 181   virtual void setProfileSymbolList(ProfileSymbolList *PSL) override {
 182     ProfSymList = PSL;
 183   };
 184
 185 private:
 186   virtual void initSectionLayout() override {
 187     SectionLayout = {SecProfSummary, SecNameTable, SecLBRProfile,
 188                      SecProfileSymbolList};
 189   };
 190   virtual std::error_code
 191   writeSections(const StringMap<FunctionSamples> &ProfileMap) override;
 192   ProfileSymbolList *ProfSymList = nullptr;
 193 };
 194
 195 // CompactBinary is a compact format of binary profile which both reduces
 196 // the profile size and the load time needed when compiling. It has two
 197 // major difference with Binary format.
 198 // 1. It represents all the strings in name table using md5 hash.
 199 // 2. It saves a function offset table which maps function name index to
 200 // the offset of its function profile to the start of the binary profile,
 201 // so by using the function offset table, for those function profiles which
 202 // will not be needed when compiling a module, the profile reader does't
 203 // have to read them and it saves compile time if the profile size is huge.
 204 // The layout of the compact format is shown as follows:
 205 //
 206 //    Part1: Profile header, the same as binary format, containing magic
 207 //           number, version, summary, name table...
 208 //    Part2: Function Offset Table Offset, which saves the position of
 209 //           Part4.
 210 //    Part3: Function profile collection
 211 //             function1 profile start
 212 //                 ....
 213 //             function2 profile start
 214 //                 ....
 215 //             function3 profile start
 216 //                 ....
 217 //                ......
 218 //    Part4: Function Offset Table
 219 //             function1 name index --> function1 profile start
 220 //             function2 name index --> function2 profile start
 221 //             function3 name index --> function3 profile start
 222 //
 223 // We need Part2 because profile reader can use it to find out and read
 224 // function offset table without reading Part3 first.
 225 class SampleProfileWriterCompactBinary : public SampleProfileWriterBinary {
 226   using SampleProfileWriterBinary::SampleProfileWriterBinary;
 227
 228 public:
 229   virtual std::error_code writeSample(const FunctionSamples &S) override;
 230   virtual std::error_code
 231   write(const StringMap<FunctionSamples> &ProfileMap) override;
 232
 233 protected:
 234   /// The table mapping from function name to the offset of its FunctionSample
 235   /// towards profile start.
 236   MapVector<StringRef, uint64_t> FuncOffsetTable;
 237   /// The offset of the slot to be filled with the offset of FuncOffsetTable
 238   /// towards profile start.
 239   uint64_t TableOffset;
 240   virtual std::error_code writeNameTable() override;
 241   virtual std::error_code
 242   writeHeader(const StringMap<FunctionSamples> &ProfileMap) override;
 243   std::error_code writeFuncOffsetTable();
 244 };
 245
 246 } // end namespace sampleprof
 247 } // end namespace llvm
 248
 249 #endif // LLVM_PROFILEDATA_SAMPLEPROFWRITER_H