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/*
* Copyright (C) 2015-2021 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 "PolymorphicCallStubRoutine.h"
#include "CachedCall.h"
#include "CallLinkInfo.h"
#include "CodeBlock.h"
#include "FullCodeOrigin.h"
#include "JSCJSValueInlines.h"
#include "LinkBuffer.h"
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
void PolymorphicCallNode::unlinkOrUpgradeImpl(VM& vm, CodeBlock* oldCodeBlock, CodeBlock* newCodeBlock)
{
// We first remove itself from the linked-list before unlinking callLinkInfo.
// The reason is that callLinkInfo can potentially link PolymorphicCallNode's stub itself, and it may destroy |this| (the other CallLinkInfo
// does not do it since it is not chained in PolymorphicCallStubRoutine).
if (isOnList())
remove();
if (!m_cleared) {
if (!newCodeBlock || !owner()->upgradeIfPossible(vm, oldCodeBlock, newCodeBlock, m_index)) {
m_cleared = true;
CallLinkInfo* callLinkInfo = owner()->callLinkInfo();
dataLogLnIf(Options::dumpDisassembly(), "Unlinking polymorphic call bc#", callLinkInfo->codeOrigin().bytecodeIndex());
callLinkInfo->unlinkOrUpgrade(vm, oldCodeBlock, newCodeBlock);
}
}
}
void PolymorphicCallNode::clear()
{
m_cleared = true;
}
PolymorphicCallStubRoutine* PolymorphicCallNode::owner()
{
return std::bit_cast<PolymorphicCallStubRoutine*>(this - m_index + m_totalSize);
}
void PolymorphicCallCase::dump(PrintStream& out) const
{
out.print("<variant = ", m_variant, ", codeBlock = ", pointerDump(m_codeBlock), ">");
}
PolymorphicCallStubRoutine::PolymorphicCallStubRoutine(unsigned headerSize, unsigned trailingSize, const MacroAssemblerCodeRef<JITStubRoutinePtrTag>& code, VM& vm, JSCell* owner, CallFrame* callerFrame, CallLinkInfo& callLinkInfo, const Vector<CallSlot, 16>& callSlots, bool notUsingCounting, bool isClosureCall)
: GCAwareJITStubRoutine(Type::PolymorphicCallStubRoutineType, code, owner, /* isCodeImmutable */ true)
, ButterflyArray<PolymorphicCallStubRoutine, PolymorphicCallNode, CallSlot>(headerSize, trailingSize)
, m_callLinkInfo(&callLinkInfo)
, m_notUsingCounting(notUsingCounting)
, m_isClosureCall(isClosureCall)
{
for (unsigned index = 0; index < callSlots.size(); ++index) {
auto& slot = trailingSpan()[index];
slot = callSlots[index];
if (callerFrame && !callerFrame->isNativeCalleeFrame())
dataLogLnIf(shouldDumpDisassemblyFor(callerFrame->codeBlock()), "Linking polymorphic call in ", FullCodeOrigin(callerFrame->codeBlock(), callerFrame->codeOrigin()), " to ", CallVariant(slot.m_calleeOrExecutable), ", codeBlock = ", pointerDump(slot.m_codeBlock));
auto& callNode = leadingSpan()[index];
callNode.initialize(index, headerSize);
if (CodeBlock* codeBlock = slot.m_codeBlock)
codeBlock->linkIncomingCall(owner, &callNode);
vm.writeBarrier(owner, slot.m_calleeOrExecutable);
}
WTF::storeStoreFence();
makeGCAware(vm);
}
bool PolymorphicCallStubRoutine::upgradeIfPossible(VM&, CodeBlock* oldCodeBlock, CodeBlock* newCodeBlock, uint8_t index)
{
// It is possible that we can just upgrade the CallSlot and continue using this PolymorphicCallStubRoutine instead of unlinking CallLinkInfo.
auto& callNode = leadingSpan()[index];
auto& slot = trailingSpan()[index];
if (callNode.isOnList())
return false;
if (slot.m_codeBlock != oldCodeBlock)
return false;
auto target = newCodeBlock->jitCode()->addressForCall(slot.m_arityCheckMode);
slot.m_codeBlock = newCodeBlock;
slot.m_target = target;
newCodeBlock->linkIncomingCall(nullptr, &callNode); // This is just relinking. So owner and caller frame can be nullptr.
return true;
}
CallVariantList PolymorphicCallStubRoutine::variants() const
{
CallVariantList result;
forEachDependentCell([&](JSCell* cell) {
result.append(CallVariant(cell));
});
return result;
}
bool PolymorphicCallStubRoutine::hasEdges() const
{
// The FTL does not count edges in its poly call stub routines. If the FTL went poly call, then
// it's not meaningful to keep profiling - we can just leave it at that. Remember, the FTL would
// have had full edge profiling from the DFG, and based on this information, it would have
// decided to go poly.
//
// There probably are very-difficult-to-imagine corner cases where the FTL not doing edge
// profiling is bad for polyvariant inlining. But polyvariant inlining is profitable sometimes
// while not having to increment counts is profitable always. So, we let the FTL run faster and
// not keep counts.
return !m_notUsingCounting;
}
CallEdgeList PolymorphicCallStubRoutine::edges() const
{
CallEdgeList result;
unsigned index = 0;
forEachDependentCell([&](JSCell* cell) {
unsigned count = trailingSpan()[index].m_count;
result.append(CallEdge(CallVariant(cell), count));
++index;
});
return result;
}
void PolymorphicCallStubRoutine::clearCallNodesFor(CallLinkInfo*)
{
for (auto& callNode : leadingSpan())
callNode.clear();
}
bool PolymorphicCallStubRoutine::visitWeakImpl(VM& vm)
{
bool isStillLive = true;
for (unsigned i = 0, size = std::size(trailingSpan()) - 1; i < size; ++i) {
auto& slot = trailingSpan()[i];
if (!slot.m_calleeOrExecutable) {
isStillLive = false;
continue;
}
if (!vm.heap.isMarked(slot.m_calleeOrExecutable)) {
slot = CallSlot();
isStillLive = false;
continue;
}
}
return isStillLive;
}
void PolymorphicCallStubRoutine::markRequiredObjectsImpl(AbstractSlotVisitor&)
{
}
void PolymorphicCallStubRoutine::markRequiredObjectsImpl(SlotVisitor&)
{
}
void PolymorphicCallStubRoutine::destroy(PolymorphicCallStubRoutine* derived)
{
delete derived;
}
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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