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/*
* Copyright (C) 2014 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.
*/
#ifndef DFGArithMode_h
#define DFGArithMode_h
#if ENABLE(DFG_JIT)
namespace JSC { namespace DFG {
// Arith::Mode describes the mode of an arithmetic operation that speculates integer.
// Note that not all modes are valid for all operations.
namespace Arith {
enum Mode {
NotSet, // Arithmetic mode is either not relevant because we're using doubles anyway or we are at a phase in compilation where we don't know what we're doing, yet. Should never see this after FixupPhase except for nodes that take doubles as inputs already.
Unchecked, // Don't check anything and just do the direct hardware operation.
CheckOverflow, // Check for overflow but don't bother with negative zero.
CheckOverflowAndNegativeZero, // Check for both overflow and negative zero.
DoOverflow // Up-convert to the smallest type that soundly represents all possible results after input type speculation.
};
} // namespace Arith
inline bool doesOverflow(Arith::Mode mode)
{
switch (mode) {
case Arith::NotSet:
ASSERT_NOT_REACHED();
#if ASSERT_DISABLED
FALLTHROUGH;
#endif
case Arith::Unchecked:
case Arith::CheckOverflow:
case Arith::CheckOverflowAndNegativeZero:
return false;
case Arith::DoOverflow:
return true;
}
ASSERT_NOT_REACHED();
return true;
}
// It's only valid to call this once you've determined that you don't need to *do*
// overflow. For most nodes, that's implicit.
inline bool shouldCheckOverflow(Arith::Mode mode)
{
switch (mode) {
case Arith::NotSet:
case Arith::DoOverflow:
ASSERT_NOT_REACHED();
return true;
case Arith::Unchecked:
return false;
case Arith::CheckOverflow:
case Arith::CheckOverflowAndNegativeZero:
return true;
}
ASSERT_NOT_REACHED();
return true;
}
inline bool shouldCheckNegativeZero(Arith::Mode mode)
{
switch (mode) {
case Arith::NotSet:
case Arith::DoOverflow:
ASSERT_NOT_REACHED();
return true;
case Arith::Unchecked:
case Arith::CheckOverflow:
return false;
case Arith::CheckOverflowAndNegativeZero:
return true;
}
ASSERT_NOT_REACHED();
return true;
}
inline bool subsumes(Arith::Mode earlier, Arith::Mode later)
{
switch (earlier) {
case Arith::CheckOverflow:
switch (later) {
case Arith::Unchecked:
case Arith::CheckOverflow:
return true;
default:
return false;
}
case Arith::CheckOverflowAndNegativeZero:
switch (later) {
case Arith::Unchecked:
case Arith::CheckOverflow:
case Arith::CheckOverflowAndNegativeZero:
return true;
default:
return false;
}
default:
return earlier == later;
}
}
} } // namespace JSC::DFG
namespace WTF {
class PrintStream;
void printInternal(PrintStream&, JSC::DFG::Arith::Mode);
} // namespace WTF
#endif // ENABLE(DFG_JIT)
#endif // DFGArithMode_h
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