src/libcompiler_builtins/compiler-rt/lib/fuzzer/FuzzerMerge.h

   1 //===- FuzzerMerge.h - merging corpa ----------------------------*- C++ -* ===//
   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 // Merging Corpora.
  10 //
  11 // The task:
  12 //   Take the existing corpus (possibly empty) and merge new inputs into
  13 //   it so that only inputs with new coverage ('features') are added.
  14 //   The process should tolerate the crashes, OOMs, leaks, etc.
  15 //
  16 // Algorithm:
  17 //   The outter process collects the set of files and writes their names
  18 //   into a temporary "control" file, then repeatedly launches the inner
  19 //   process until all inputs are processed.
  20 //   The outer process does not actually execute the target code.
  21 //
  22 //   The inner process reads the control file and sees a) list of all the inputs
  23 //   and b) the last processed input. Then it starts processing the inputs one
  24 //   by one. Before processing every input it writes one line to control file:
  25 //   STARTED INPUT_ID INPUT_SIZE
  26 //   After processing an input it write another line:
  27 //   DONE INPUT_ID Feature1 Feature2 Feature3 ...
  28 //   If a crash happens while processing an input the last line in the control
  29 //   file will be "STARTED INPUT_ID" and so the next process will know
  30 //   where to resume.
  31 //
  32 //   Once all inputs are processed by the innner process(es) the outer process
  33 //   reads the control files and does the merge based entirely on the contents
  34 //   of control file.
  35 //   It uses a single pass greedy algorithm choosing first the smallest inputs
  36 //   within the same size the inputs that have more new features.
  37 //
  38 //===----------------------------------------------------------------------===//
  39
  40 #ifndef LLVM_FUZZER_MERGE_H
  41 #define LLVM_FUZZER_MERGE_H
  42
  43 #include "FuzzerDefs.h"
  44
  45 #include <istream>
  46 #include <ostream>
  47 #include <set>
  48 #include <vector>
  49
  50 namespace fuzzer {
  51
  52 struct MergeFileInfo {
  53   std::string Name;
  54   size_t Size = 0;
  55   Vector<uint32_t> Features;
  56 };
  57
  58 struct Merger {
  59   Vector<MergeFileInfo> Files;
  60   size_t NumFilesInFirstCorpus = 0;
  61   size_t FirstNotProcessedFile = 0;
  62   std::string LastFailure;
  63
  64   bool Parse(std::istream &IS, bool ParseCoverage);
  65   bool Parse(const std::string &Str, bool ParseCoverage);
  66   void ParseOrExit(std::istream &IS, bool ParseCoverage);
  67   void PrintSummary(std::ostream &OS);
  68   Set<uint32_t> ParseSummary(std::istream &IS);
  69   size_t Merge(const Set<uint32_t> &InitialFeatures,
  70                Vector<std::string> *NewFiles);
  71   size_t Merge(Vector<std::string> *NewFiles) {
  72     return Merge(Set<uint32_t>{}, NewFiles);
  73   }
  74   size_t ApproximateMemoryConsumption() const;
  75   Set<uint32_t> AllFeatures() const;
  76 };
  77
  78 }  // namespace fuzzer
  79
  80 #endif  // LLVM_FUZZER_MERGE_H