1/*
2 * Copyright (C) 2012, 2014 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(JIT)
29
30#include "MacroAssembler.h"
31#include "RegisterSet.h"
32#include "TempRegisterSet.h"
33
34namespace JSC {
35
36struct ScratchBuffer;
37
38// This class provides a low-level register allocator for use in stubs.
39
40class ScratchRegisterAllocator {
41public:
42 ScratchRegisterAllocator() { }
43 ScratchRegisterAllocator(const RegisterSet& usedRegisters);
44 ~ScratchRegisterAllocator();
45
46 void lock(GPRReg);
47 void lock(FPRReg);
48 void lock(JSValueRegs);
49
50 template<typename BankInfo>
51 typename BankInfo::RegisterType allocateScratch();
52
53 GPRReg allocateScratchGPR();
54 FPRReg allocateScratchFPR();
55
56 bool didReuseRegisters() const
57 {
58 return !!m_numberOfReusedRegisters;
59 }
60
61 unsigned numberOfReusedRegisters() const
62 {
63 return m_numberOfReusedRegisters;
64 }
65
66 RegisterSet usedRegisters() const { return m_usedRegisters; }
67
68 enum class ExtraStackSpace { SpaceForCCall, NoExtraSpace };
69
70 struct PreservedState {
71 PreservedState()
72 : numberOfBytesPreserved(std::numeric_limits<unsigned>::max())
73 , extraStackSpaceRequirement(ExtraStackSpace::SpaceForCCall)
74 { }
75
76 PreservedState(unsigned numberOfBytes, ExtraStackSpace extraStackSpace)
77 : numberOfBytesPreserved(numberOfBytes)
78 , extraStackSpaceRequirement(extraStackSpace)
79 { }
80
81 explicit operator bool() const { return numberOfBytesPreserved != std::numeric_limits<unsigned>::max(); }
82
83 unsigned numberOfBytesPreserved;
84 ExtraStackSpace extraStackSpaceRequirement;
85 };
86
87 PreservedState preserveReusedRegistersByPushing(MacroAssembler& jit, ExtraStackSpace);
88 void restoreReusedRegistersByPopping(MacroAssembler& jit, const PreservedState&);
89
90 RegisterSet usedRegistersForCall() const;
91
92 unsigned desiredScratchBufferSizeForCall() const;
93
94 void preserveUsedRegistersToScratchBufferForCall(MacroAssembler& jit, ScratchBuffer* scratchBuffer, GPRReg scratchGPR = InvalidGPRReg);
95 void restoreUsedRegistersFromScratchBufferForCall(MacroAssembler& jit, ScratchBuffer* scratchBuffer, GPRReg scratchGPR = InvalidGPRReg);
96
97 static unsigned preserveRegistersToStackForCall(MacroAssembler& jit, const RegisterSet& usedRegisters, unsigned extraPaddingInBytes);
98 static void restoreRegistersFromStackForCall(MacroAssembler& jit, const RegisterSet& usedRegisters, const RegisterSet& ignore, unsigned numberOfStackBytesUsedForRegisterPreservation, unsigned extraPaddingInBytes);
99
100private:
101 RegisterSet m_usedRegisters;
102 TempRegisterSet m_lockedRegisters;
103 TempRegisterSet m_scratchRegisters;
104 unsigned m_numberOfReusedRegisters;
105};
106
107} // namespace JSC
108
109#endif // ENABLE(JIT)
110