1  /*
 2   * Copyright (C) 2019 Apple Inc. All rights reserved.
 3   *
 4   * Redistribution and use in source and binary forms, with or without
 5   * modification, are permitted provided that the following conditions
 6   * are met:
 7   * 1. Redistributions of source code must retain the above copyright
 8   *    notice, this list of conditions and the following disclaimer.
 9   * 2. Redistributions in binary form must reproduce the above copyright
10   *    notice, this list of conditions and the following disclaimer in the
11   *    documentation and/or other materials provided with the distribution.
12   *
13   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24   */
25  
26  #include "config.h"
27  #include "NarrowingNumberPredictionFuzzerAgent.h"
28  
29  #include "CodeBlock.h"
30  
31  namespace JSC {
32  
33  NarrowingNumberPredictionFuzzerAgent::NarrowingNumberPredictionFuzzerAgent(VM& vm)
34      : NumberPredictionFuzzerAgent(vm)
35  {
36  }
37  
38  SpeculatedType NarrowingNumberPredictionFuzzerAgent::getPrediction(CodeBlock* codeBlock, const CodeOrigin& codeOrigin, SpeculatedType original)
39  {
40      auto locker = holdLock(m_lock);
41  
42      if (!(original && speculationChecked(original, SpecBytecodeNumber)))
43          return original;
44  
45      Vector<SpeculatedType> numberTypesThatCouldBePartOfSpeculation;
46      for (auto numberType : bytecodeNumberTypes()) {
47          if (numberType & original)
48              numberTypesThatCouldBePartOfSpeculation.append(numberType);
49      }
50  
51      unsigned numberOfTypesToKeep = m_random.getUint32(numberTypesThatCouldBePartOfSpeculation.size()) + 1;
52      if (numberOfTypesToKeep == numberTypesThatCouldBePartOfSpeculation.size())
53          return original;
54  
55      SpeculatedType generated = SpecNone;
56      for (unsigned i = 0; i < numberOfTypesToKeep; i++) {
57          unsigned indexOfTypeToKeep = m_random.getUint32(numberTypesThatCouldBePartOfSpeculation.size());
58          mergeSpeculation(generated, numberTypesThatCouldBePartOfSpeculation[indexOfTypeToKeep]);
59          numberTypesThatCouldBePartOfSpeculation.remove(indexOfTypeToKeep);
60      }
61  
62      if (Options::dumpFuzzerAgentPredictions())
63          dataLogLn("NarrowingNumberPredictionFuzzerAgent::getPrediction name:(", codeBlock->inferredName(), "#", codeBlock->hashAsStringIfPossible(), "),bytecodeIndex:(", codeOrigin.bytecodeIndex(), "),original:(", SpeculationDump(original), "),generated:(", SpeculationDump(generated), ")");
64  
65      return generated;
66  }
67  
68  } // namespace JSC