1  /*
 2   * Copyright (C) 2018 Yusuke Suzuki <utatane.tea@gmail.com>.
 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 "ParseHash.h"
28  
29  #include "SourceCode.h"
30  #include <wtf/SHA1.h>
31  
32  namespace JSC {
33  
34  ParseHash::ParseHash(const SourceCode& sourceCode)
35  {
36      SHA1 sha1;
37      sha1.addBytes(sourceCode.toUTF8());
38      SHA1::Digest digest;
39      sha1.computeHash(digest);
40      unsigned hash = digest[0] | (digest[1] << 8) | (digest[2] << 16) | (digest[3] << 24);
41  
42      if (hash == 0 || hash == 1)
43          hash += 0x2d5a93d0; // Ensures a non-zero hash, and gets us #Azero0 for CodeForCall and #Azero1 for CodeForConstruct.
44      static_assert(static_cast<unsigned>(CodeForCall) == 0, "");
45      static_assert(static_cast<unsigned>(CodeForConstruct) == 1, "");
46      unsigned hashForCall = hash ^ static_cast<unsigned>(CodeForCall);
47      unsigned hashForConstruct = hash ^ static_cast<unsigned>(CodeForConstruct);
48  
49      m_hashForCall = CodeBlockHash(hashForCall);
50      m_hashForConstruct = CodeBlockHash(hashForConstruct);
51      ASSERT(hashForCall);
52      ASSERT(hashForConstruct);
53  }
54  
55  } // namespace JSC
56