1  /*
 2   * Copyright (C) 2017 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  #pragma once
27  
28  #if ENABLE(ASSEMBLER)
29  
30  #include "MacroAssembler.h"
31  
32  namespace JSC {
33  
34  class AllowMacroScratchRegisterUsageIf {
35  public:
36      AllowMacroScratchRegisterUsageIf(MacroAssembler& masm, bool allowIfTrue)
37          : m_masm(masm)
38          , m_allowIfTrue(allowIfTrue)
39          , m_oldValueOfAllowScratchRegister(masm.m_allowScratchRegister)
40      {
41          if (m_allowIfTrue) {
42  #if CPU(ARM64)
43              if (!m_oldValueOfAllowScratchRegister)
44                  m_masm.invalidateAllTempRegisters();
45  #endif
46              masm.m_allowScratchRegister = true;
47          }
48      }
49  
50      ~AllowMacroScratchRegisterUsageIf()
51      {
52          if (m_allowIfTrue)
53              m_masm.m_allowScratchRegister = m_oldValueOfAllowScratchRegister;
54      }
55  
56  private:
57      MacroAssembler& m_masm;
58      bool m_allowIfTrue;
59      bool m_oldValueOfAllowScratchRegister;
60  };
61  
62  } // namespace JSC
63  
64  #endif // ENABLE(ASSEMBLER)