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AirStackAllocation.cpp
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126 lines (108 loc) · 5.16 KB
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/*
* Copyright (C) 2017-2019 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.
*/
#include "config.h"
#include "AirStackAllocation.h"
#if ENABLE(B3_JIT)
#include "AirCode.h"
#include "StackAlignment.h"
#include <wtf/ListDump.h>
namespace JSC { namespace B3 { namespace Air {
namespace {
namespace AirStackAllocationInternal {
static constexpr bool verbose = false;
}
template<typename Collection>
void updateFrameSizeBasedOnStackSlotsImpl(Code& code, const Collection& collection)
{
unsigned frameSize = 0;
for (StackSlot* slot : collection)
frameSize = std::max(frameSize, static_cast<unsigned>(-slot->offsetFromFP()));
code.setFrameSize(WTF::roundUpToMultipleOf<stackAlignmentBytes()>(frameSize) + stackAdjustmentForAlignment());
}
} // anonymous namespace
void assign(StackSlot* slot, const Vector<StackSlot*>& otherSlots)
{
dataLogLnIf(AirStackAllocationInternal::verbose, "Attempting to assign ", pointerDump(slot), " with interference ", pointerListDump(otherSlots));
// Start candidate at the top of the frame and push it down past any overlapping slot.
intptr_t offsetFromFP = -static_cast<intptr_t>(slot->byteSize());
offsetFromFP = -WTF::roundUpToMultipleOf(slot->alignment(), -offsetFromFP);
intptr_t prevOffset = 0;
for (StackSlot* otherSlot : otherSlots) {
ASSERT(otherSlot->offsetFromFP() < 0);
ASSERT_UNUSED(prevOffset, otherSlot->offsetFromFP() <= prevOffset);
prevOffset = otherSlot->offsetFromFP();
bool overlap = WTF::rangesOverlap(
offsetFromFP,
offsetFromFP + static_cast<intptr_t>(slot->byteSize()),
otherSlot->offsetFromFP(),
otherSlot->offsetFromFP() + static_cast<intptr_t>(otherSlot->byteSize()));
if (overlap) {
offsetFromFP = otherSlot->offsetFromFP() - static_cast<intptr_t>(slot->byteSize());
offsetFromFP = -WTF::roundUpToMultipleOf(slot->alignment(), -offsetFromFP);
}
}
dataLogLnIf(AirStackAllocationInternal::verbose, "Assigned ", pointerDump(slot), " to ", offsetFromFP);
slot->setOffsetFromFP(offsetFromFP);
}
Vector<StackSlot*> allocateAndGetEscapedStackSlotsWithoutChangingFrameSize(Code& code)
{
// Allocate all of the escaped slots in order. This is kind of a crazy algorithm to allow for
// the possibility of stack slots being assigned frame offsets before we even get here.
RELEASE_ASSERT(code.frameSize() == stackAdjustmentForAlignment());
Vector<StackSlot*> assignedEscapedStackSlots;
Vector<StackSlot*> escapedStackSlotsWorklist;
for (StackSlot* slot : code.stackSlots()) {
if (slot->isLocked()) {
if (slot->offsetFromFP())
assignedEscapedStackSlots.append(slot);
else
escapedStackSlotsWorklist.append(slot);
} else {
// It would be super strange to have an unlocked stack slot that has an offset already.
ASSERT(!slot->offsetFromFP());
}
}
std::ranges::sort(assignedEscapedStackSlots, std::ranges::greater { }, &StackSlot::offsetFromFP);
// This is a fairly expensive loop, but it's OK because we'll usually only have a handful of
// escaped stack slots.
while (!escapedStackSlotsWorklist.isEmpty()) {
StackSlot* slot = escapedStackSlotsWorklist.takeLast();
assign(slot, assignedEscapedStackSlots);
auto it = std::ranges::upper_bound(assignedEscapedStackSlots, slot->offsetFromFP(), std::ranges::greater { }, &StackSlot::offsetFromFP);
assignedEscapedStackSlots.insert(it - assignedEscapedStackSlots.begin(), slot);
}
return assignedEscapedStackSlots;
}
void allocateEscapedStackSlots(Code& code)
{
updateFrameSizeBasedOnStackSlotsImpl(
code, allocateAndGetEscapedStackSlotsWithoutChangingFrameSize(code));
}
void updateFrameSizeBasedOnStackSlots(Code& code)
{
updateFrameSizeBasedOnStackSlotsImpl(code, code.stackSlots());
}
} } } // namespace JSC::B3::Air
#endif // ENABLE(B3_JIT)