131 lines
3.8 KiB
C++
131 lines
3.8 KiB
C++
/*
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* Copyright (C) 2015-2017 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#if ENABLE(B3_JIT)
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#include "AirArg.h"
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namespace JSC { namespace B3 { namespace Air {
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class Code;
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class TmpWidth {
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public:
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TmpWidth();
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TmpWidth(Code&);
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~TmpWidth();
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template <Bank bank>
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void recompute(Code&);
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// The width of a Tmp is the number of bits that you need to be able to track without some trivial
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// recovery. A Tmp may have a "subwidth" (say, Width32 on a 64-bit system) if either of the following
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// is true:
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//
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// - The high bits are never read.
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// - The high bits are always zero.
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//
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// This doesn't tell you which of those properties holds, but you can query that using the other
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// methods.
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Width width(Tmp tmp) const
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{
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Widths tmpWidths = widths(tmp);
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return std::min(tmpWidths.use, tmpWidths.def);
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}
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// Return the minimum required width for all defs/uses of this Tmp.
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Width requiredWidth(Tmp tmp)
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{
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Widths tmpWidths = widths(tmp);
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return std::max(tmpWidths.use, tmpWidths.def);
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}
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// This indirectly tells you how much of the tmp's high bits are guaranteed to be zero. The number of
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// high bits that are zero are:
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//
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// TotalBits - defWidth(tmp)
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//
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// Where TotalBits are the total number of bits in the register, so 64 on a 64-bit system.
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Width defWidth(Tmp tmp) const
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{
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return widths(tmp).def;
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}
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// This tells you how much of Tmp is going to be read.
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Width useWidth(Tmp tmp) const
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{
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return widths(tmp).use;
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}
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private:
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struct Widths {
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Widths() { }
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Widths(Bank bank)
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: use(minimumWidth(bank))
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, def(minimumWidth(bank))
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{
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}
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Widths(Width useArg, Width defArg)
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: use(useArg)
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, def(defArg)
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{
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}
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void dump(PrintStream& out) const;
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Width use;
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Width def;
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};
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inline Widths& widths(Tmp);
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const Widths& widths(Tmp tmp) const
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{
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return const_cast<TmpWidth*>(this)->widths(tmp);
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}
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void addWidths(Tmp tmp, Widths tmpWidths)
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{
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widths(tmp) = tmpWidths;
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}
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Vector<Widths>& widthsVector(Bank bank)
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{
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return bank == GP ? m_widthGP : m_widthFP;
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}
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// These are initialized at the beginning of recompute<bank>, which is called in the constructor for both values of bank.
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Vector<Widths> m_widthGP;
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Vector<Widths> m_widthFP;
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};
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} } } // namespace JSC::B3::Air
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#endif // ENABLE(B3_JIT)
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