mirror of
https://github.com/darlinghq/darling-JavaScriptCore.git
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123 lines
4.6 KiB
C++
123 lines
4.6 KiB
C++
/*
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* Copyright (C) 2012-2018 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(JIT)
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#include "ExecutableAllocator.h"
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#include "MacroAssemblerCodeRef.h"
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namespace JSC {
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class JITStubRoutineSet;
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class VM;
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// This is a base-class for JIT stub routines, and also the class you want
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// to instantiate directly if you have a routine that does not need any
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// help from the GC. If in doubt, use one of the other stub routines. But
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// if you know for sure that the stub routine cannot be on the stack while
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// someone triggers a stub routine reset, then using this will speed up
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// memory reclamation. One case where a stub routine satisfies this
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// condition is if it doesn't make any calls, to either C++ or JS code. In
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// such a routine you know that it cannot be on the stack when anything
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// interesting happens.
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// See GCAwareJITStubRoutine.h for the other stub routines.
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class JITStubRoutine {
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WTF_MAKE_NONCOPYABLE(JITStubRoutine);
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WTF_MAKE_FAST_ALLOCATED;
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public:
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JITStubRoutine(const MacroAssemblerCodeRef<JITStubRoutinePtrTag>& code)
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: m_code(code)
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, m_refCount(1)
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{
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}
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// Use this if you want to pass a CodePtr to someone who insists on taking
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// a RefPtr<JITStubRoutine>.
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static Ref<JITStubRoutine> createSelfManagedRoutine(
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MacroAssemblerCodePtr<JITStubRoutinePtrTag> rawCodePointer)
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{
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return adoptRef(*new JITStubRoutine(MacroAssemblerCodeRef<JITStubRoutinePtrTag>::createSelfManagedCodeRef(rawCodePointer)));
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}
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virtual ~JITStubRoutine();
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virtual void aboutToDie() { }
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// MacroAssemblerCodeRef is copyable, but at the cost of reference
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// counting churn. Returning a reference is a good way of reducing
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// the churn.
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const MacroAssemblerCodeRef<JITStubRoutinePtrTag>& code() const { return m_code; }
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static MacroAssemblerCodePtr<JITStubRoutinePtrTag> asCodePtr(Ref<JITStubRoutine>&& stubRoutine)
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{
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MacroAssemblerCodePtr<JITStubRoutinePtrTag> result = stubRoutine->code().code();
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ASSERT(!!result);
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return result;
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}
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void ref()
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{
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m_refCount++;
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}
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void deref()
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{
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if (--m_refCount)
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return;
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observeZeroRefCount();
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}
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// Helpers for the GC to determine how to deal with marking JIT stub
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// routines.
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uintptr_t startAddress() const { return m_code.executableMemory()->startAsInteger(); }
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uintptr_t endAddress() const { return m_code.executableMemory()->endAsInteger(); }
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static uintptr_t addressStep() { return jitAllocationGranule; }
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static bool passesFilter(uintptr_t address)
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{
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return isJITPC(bitwise_cast<void*>(address));
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}
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// Return true if you are still valid after. Return false if you are now invalid. If you return
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// false, you will usually not do any clearing because the idea is that you will simply be
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// destroyed.
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virtual bool visitWeak(VM&);
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protected:
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virtual void observeZeroRefCount();
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MacroAssemblerCodeRef<JITStubRoutinePtrTag> m_code;
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unsigned m_refCount;
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};
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// Helper for the creation of simple stub routines that need no help from the GC.
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#define FINALIZE_CODE_FOR_STUB(codeBlock, patchBuffer, resultPtrTag, ...) \
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(adoptRef(new JITStubRoutine(FINALIZE_CODE_FOR((codeBlock), (patchBuffer), (resultPtrTag), __VA_ARGS__))))
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} // namespace JSC
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#endif // ENABLE(JIT)
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