bytecode/CodeBlockHash.cpp

   1 /*
   2  * Copyright (C) 2012, 2013 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 "CodeBlockHash.h"
  28
  29 #include "SourceCode.h"
  30 #include <wtf/SHA1.h>
  31 #include <wtf/SixCharacterHash.h>
  32
  33 namespace JSC {
  34
  35 CodeBlockHash::CodeBlockHash(const char* string)
  36     : m_hash(sixCharacterHashStringToInteger(string))
  37 {
  38 }
  39
  40 CodeBlockHash::CodeBlockHash(const SourceCode& sourceCode, CodeSpecializationKind kind)
  41     : m_hash(0)
  42 {
  43     SHA1 sha1;
  44     sha1.addBytes(sourceCode.toUTF8());
  45     SHA1::Digest digest;
  46     sha1.computeHash(digest);
  47     m_hash += digest[0] | (digest[1] << 8) | (digest[2] << 16) | (digest[3] << 24);
  48     m_hash ^= static_cast<unsigned>(kind);
  49
  50     // Ensure that 0 corresponds to the hash not having been computed.
  51     if (!m_hash)
  52         m_hash = 1;
  53 }
  54
  55 void CodeBlockHash::dump(PrintStream& out) const
  56 {
  57     std::array<char, 7> buffer = integerToSixCharacterHashString(m_hash);
  58
  59 #if !ASSERT_DISABLED
  60     CodeBlockHash recompute(buffer.data());
  61     ASSERT(recompute == *this);
  62 #endif // !ASSERT_DISABLED
  63
  64     out.print(buffer.data());
  65 }
  66
  67 } // namespace JSC
  68