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/*
* Copyright (C) 2015-2017 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. ``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
#if ENABLE(B3_JIT)
#include "AirArg.h"
#include "B3Bank.h"
namespace JSC { namespace B3 { namespace Air {
class Code;
class TmpWidth {
public:
TmpWidth();
TmpWidth(Code&);
~TmpWidth();
template <Bank bank>
void recompute(Code&);
// The width of a Tmp is the number of bits that you need to be able to track without some trivial
// recovery. A Tmp may have a "subwidth" (say, Width32 on a 64-bit system) if either of the following
// is true:
//
// - The high bits are never read.
// - The high bits are always zero.
//
// This doesn't tell you which of those properties holds, but you can query that using the other
// methods.
Width width(Tmp tmp) const
{
Widths tmpWidths = widths(tmp);
return std::min(tmpWidths.use, tmpWidths.def);
}
// Return the minimum required width for all defs/uses of this Tmp.
Width requiredWidth(Tmp tmp)
{
Widths tmpWidths = widths(tmp);
return std::max(tmpWidths.use, tmpWidths.def);
}
// This indirectly tells you how much of the tmp's high bits are guaranteed to be zero. The number of
// high bits that are zero are:
//
// TotalBits - defWidth(tmp)
//
// Where TotalBits are the total number of bits in the register, so 64 on a 64-bit system.
Width defWidth(Tmp tmp) const
{
return widths(tmp).def;
}
// This tells you how much of Tmp is going to be read.
Width useWidth(Tmp tmp) const
{
return widths(tmp).use;
}
private:
struct Widths {
Widths() { }
Widths(Bank bank)
: use(minimumWidth(bank))
, def(minimumWidth(bank))
{
}
Widths(Width useArg, Width defArg)
: use(useArg)
, def(defArg)
{
}
void dump(PrintStream& out) const;
Width use;
Width def;
};
inline Widths& widths(Tmp);
const Widths& widths(Tmp tmp) const
{
return const_cast<TmpWidth*>(this)->widths(tmp);
}
void addWidths(Tmp tmp, Widths tmpWidths)
{
widths(tmp) = tmpWidths;
}
Vector<Widths>& widthsVector(Bank bank)
{
return bank == GP ? m_widthGP : m_widthFP;
}
// These are initialized at the beginning of recompute<bank>, which is called in the constructor for both values of bank.
Vector<Widths> m_widthGP;
Vector<Widths> m_widthFP;
};
} } } // namespace JSC::B3::Air
#endif // ENABLE(B3_JIT)
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