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 write(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 protected:
  60   SampleProfileWriter(std::unique_ptr<raw_ostream> &OS)
  61       : OutputStream(std::move(OS)) {}
  62
  63   /// Write a file header for the profile file.
  64   virtual std::error_code
  65   writeHeader(const StringMap<FunctionSamples> &ProfileMap) = 0;
  66
  67   /// Output stream where to emit the profile to.
  68   std::unique_ptr<raw_ostream> OutputStream;
  69
  70   /// Profile summary.
  71   std::unique_ptr<ProfileSummary> Summary;
  72
  73   /// Compute summary for this profile.
  74   void computeSummary(const StringMap<FunctionSamples> &ProfileMap);
  75 };
  76
  77 /// Sample-based profile writer (text format).
  78 class SampleProfileWriterText : public SampleProfileWriter {
  79 public:
  80   std::error_code write(const FunctionSamples &S) override;
  81
  82 protected:
  83   SampleProfileWriterText(std::unique_ptr<raw_ostream> &OS)
  84       : SampleProfileWriter(OS), Indent(0) {}
  85
  86   std::error_code
  87   writeHeader(const StringMap<FunctionSamples> &ProfileMap) override {
  88     return sampleprof_error::success;
  89   }
  90
  91 private:
  92   /// Indent level to use when writing.
  93   ///
  94   /// This is used when printing inlined callees.
  95   unsigned Indent;
  96
  97   friend ErrorOr<std::unique_ptr<SampleProfileWriter>>
  98   SampleProfileWriter::create(std::unique_ptr<raw_ostream> &OS,
  99                               SampleProfileFormat Format);
 100 };
 101
 102 /// Sample-based profile writer (binary format).
 103 class SampleProfileWriterBinary : public SampleProfileWriter {
 104 public:
 105   virtual std::error_code write(const FunctionSamples &S) override;
 106   SampleProfileWriterBinary(std::unique_ptr<raw_ostream> &OS)
 107       : SampleProfileWriter(OS) {}
 108
 109 protected:
 110   virtual std::error_code writeNameTable() = 0;
 111   virtual std::error_code writeMagicIdent() = 0;
 112   virtual std::error_code
 113   writeHeader(const StringMap<FunctionSamples> &ProfileMap) override;
 114   std::error_code writeSummary();
 115   std::error_code writeNameIdx(StringRef FName);
 116   std::error_code writeBody(const FunctionSamples &S);
 117   inline void stablizeNameTable(std::set<StringRef> &V);
 118
 119   MapVector<StringRef, uint32_t> NameTable;
 120
 121 private:
 122   void addName(StringRef FName);
 123   void addNames(const FunctionSamples &S);
 124
 125   friend ErrorOr<std::unique_ptr<SampleProfileWriter>>
 126   SampleProfileWriter::create(std::unique_ptr<raw_ostream> &OS,
 127                               SampleProfileFormat Format);
 128 };
 129
 130 class SampleProfileWriterRawBinary : public SampleProfileWriterBinary {
 131   using SampleProfileWriterBinary::SampleProfileWriterBinary;
 132
 133 protected:
 134   virtual std::error_code writeNameTable() override;
 135   virtual std::error_code writeMagicIdent() override;
 136 };
 137
 138 // CompactBinary is a compact format of binary profile which both reduces
 139 // the profile size and the load time needed when compiling. It has two
 140 // major difference with Binary format.
 141 // 1. It represents all the strings in name table using md5 hash.
 142 // 2. It saves a function offset table which maps function name index to
 143 // the offset of its function profile to the start of the binary profile,
 144 // so by using the function offset table, for those function profiles which
 145 // will not be needed when compiling a module, the profile reader does't
 146 // have to read them and it saves compile time if the profile size is huge.
 147 // The layout of the compact format is shown as follows:
 148 //
 149 //    Part1: Profile header, the same as binary format, containing magic
 150 //           number, version, summary, name table...
 151 //    Part2: Function Offset Table Offset, which saves the position of
 152 //           Part4.
 153 //    Part3: Function profile collection
 154 //             function1 profile start
 155 //                 ....
 156 //             function2 profile start
 157 //                 ....
 158 //             function3 profile start
 159 //                 ....
 160 //                ......
 161 //    Part4: Function Offset Table
 162 //             function1 name index --> function1 profile start
 163 //             function2 name index --> function2 profile start
 164 //             function3 name index --> function3 profile start
 165 //
 166 // We need Part2 because profile reader can use it to find out and read
 167 // function offset table without reading Part3 first.
 168 class SampleProfileWriterCompactBinary : public SampleProfileWriterBinary {
 169   using SampleProfileWriterBinary::SampleProfileWriterBinary;
 170
 171 public:
 172   virtual std::error_code write(const FunctionSamples &S) override;
 173   virtual std::error_code
 174   write(const StringMap<FunctionSamples> &ProfileMap) override;
 175
 176 protected:
 177   /// The table mapping from function name to the offset of its FunctionSample
 178   /// towards profile start.
 179   MapVector<StringRef, uint64_t> FuncOffsetTable;
 180   /// The offset of the slot to be filled with the offset of FuncOffsetTable
 181   /// towards profile start.
 182   uint64_t TableOffset;
 183   virtual std::error_code writeNameTable() override;
 184   virtual std::error_code writeMagicIdent() override;
 185   virtual std::error_code
 186   writeHeader(const StringMap<FunctionSamples> &ProfileMap) override;
 187   std::error_code writeFuncOffsetTable();
 188 };
 189
 190 } // end namespace sampleprof
 191 } // end namespace llvm
 192
 193 #endif // LLVM_PROFILEDATA_SAMPLEPROFWRITER_H