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/*
* Copyright (C) 2013 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef RegisterAllocator_h
#define RegisterAllocator_h
#if ENABLE(CSS_SELECTOR_JIT)
#include <JavaScriptCore/MacroAssembler.h>
#include <wtf/Deque.h>
#include <wtf/Vector.h>
namespace WebCore {
#if CPU(X86_64)
static const JSC::MacroAssembler::RegisterID callerSavedRegisters[] = {
JSC::X86Registers::eax,
JSC::X86Registers::ecx,
JSC::X86Registers::esi,
JSC::X86Registers::edi,
JSC::X86Registers::r8,
JSC::X86Registers::r9,
JSC::X86Registers::r10,
JSC::X86Registers::r11
};
#else
#error RegisterAllocator has no defined registers for the architecture.
#endif
class RegisterAllocator {
public:
RegisterAllocator();
JSC::MacroAssembler::RegisterID allocateRegister()
{
RELEASE_ASSERT(!m_registers.isEmpty());
JSC::MacroAssembler::RegisterID registerID = m_registers.takeFirst();
ASSERT(!m_allocatedRegisters.contains(registerID));
m_allocatedRegisters.append(registerID);
return registerID;
}
void allocateRegister(JSC::MacroAssembler::RegisterID registerID)
{
ASSERT(!m_allocatedRegisters.contains(registerID));
for (auto it = m_registers.begin(), end = m_registers.end(); it != end; ++it) {
if (*it == registerID) {
m_registers.remove(it);
break;
}
}
m_allocatedRegisters.append(registerID);
}
void deallocateRegister(JSC::MacroAssembler::RegisterID registerID)
{
ASSERT(m_allocatedRegisters.contains(registerID));
// Most allocation/deallocation happen in stack-like order. In the common case, this
// just removes the last item.
m_allocatedRegisters.remove(m_allocatedRegisters.reverseFind(registerID));
m_registers.append(registerID);
}
const Vector<JSC::MacroAssembler::RegisterID, 8>& allocatedRegisters() const { return m_allocatedRegisters; }
private:
Deque<JSC::MacroAssembler::RegisterID, WTF_ARRAY_LENGTH(callerSavedRegisters)> m_registers;
Vector<JSC::MacroAssembler::RegisterID, WTF_ARRAY_LENGTH(callerSavedRegisters)> m_allocatedRegisters;
};
class LocalRegister {
public:
explicit LocalRegister(RegisterAllocator& allocator)
: m_allocator(allocator)
, m_register(allocator.allocateRegister())
{
}
~LocalRegister()
{
m_allocator.deallocateRegister(m_register);
}
operator JSC::MacroAssembler::RegisterID() const
{
return m_register;
}
private:
RegisterAllocator& m_allocator;
JSC::MacroAssembler::RegisterID m_register;
};
inline RegisterAllocator::RegisterAllocator()
{
for (unsigned i = 0; i < WTF_ARRAY_LENGTH(callerSavedRegisters); ++i)
m_registers.append(callerSavedRegisters[i]);
}
} // namespace WebCore
#endif // ENABLE(CSS_SELECTOR_JIT)
#endif // RegisterAllocator_h
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