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/*
* Copyright (C) 2016 Apple Inc. All rights reserved.
* Copyright (C) 2017 Yusuke Suzuki <utatane.tea@gmail.com>.
*
* 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. ``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
* 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.
*/
#pragma once
#include "Reg.h"
#include <variant>
#if ENABLE(JIT)
namespace JSC {
// It is quite unfortunate that 32 bit environment exists on DFG! This means that JSValueRegs contains 2 registers
// in such an environment. If we use GPRReg and FPRReg in SnippetParams, SnippetParams may contain
// different number of registers in 32bit and 64bit environments when we pass JSValueRegs, it is confusing.
// Therefore, we introduce an abstraction that SnippetReg, which is a polymorphic register class. It can refer FPRReg,
// GPRReg, and "JSValueRegs". Note that isGPR() will return false if the target Reg is "JSValueRegs" even if the
// environment is 64bit.
//
// FIXME: Eventually we should move this class into JSC and make is available for other JIT code.
// https://bugs.webkit.org/show_bug.cgi?id=162990
class SnippetReg {
public:
enum class Type : uint8_t {
GPR = 0,
FPR = 1,
JSValue = 2,
};
SnippetReg(GPRReg reg)
: m_variant(reg)
{
}
SnippetReg(FPRReg reg)
: m_variant(reg)
{
}
SnippetReg(JSValueRegs regs)
: m_variant(regs)
{
}
bool isGPR() const { return m_variant.index() == static_cast<unsigned>(Type::GPR); }
bool isFPR() const { return m_variant.index() == static_cast<unsigned>(Type::FPR); }
bool isJSValueRegs() const { return m_variant.index() == static_cast<unsigned>(Type::JSValue); }
GPRReg gpr() const
{
ASSERT(isGPR());
return std::get<GPRReg>(m_variant);
}
FPRReg fpr() const
{
ASSERT(isFPR());
return std::get<FPRReg>(m_variant);
}
JSValueRegs jsValueRegs() const
{
ASSERT(isJSValueRegs());
return std::get<JSValueRegs>(m_variant);
}
private:
std::variant<GPRReg, FPRReg, JSValueRegs> m_variant;
};
}
#endif
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