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/*
* Copyright (C) 2025 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
#include <wtf/Atomics.h>
#include <wtf/Lock.h>
#include <wtf/SentinelLinkedList.h>
#if ENABLE(C_LOOP)
#include <JavaScriptCore/CLoopStack.h>
#endif
namespace JSC {
class VM;
class StackManager {
public:
class Mirror : public BasicRawSentinelNode<Mirror> {
public:
void* softStackLimit() const { return m_softStackLimit; }
void* trapAwareSoftStackLimit() const { return m_trapAwareSoftStackLimit.loadRelaxed(); }
static constexpr ptrdiff_t offsetOfSoftStackLimit()
{
return OBJECT_OFFSETOF(Mirror, m_softStackLimit);
}
private:
Atomic<void*> m_trapAwareSoftStackLimit { nullptr };
void* m_softStackLimit { nullptr };
friend class LLIntOffsetsExtractor;
friend class StackManager;
};
void registerMirror(Mirror&);
void unregisterMirror(Mirror&);
bool hasStopRequest() { return trapAwareSoftStackLimit() == stopRequestMarker(); }
CONCURRENT_SAFE void requestStop();
CONCURRENT_SAFE void cancelStop();
void* softStackLimit() const { return m_softStackLimit; }
void* trapAwareSoftStackLimit() const { return m_trapAwareSoftStackLimit.loadRelaxed(); }
void setStackSoftLimit(void* newLimit);
static constexpr ptrdiff_t offsetOfSoftStackLimit()
{
return OBJECT_OFFSETOF(StackManager, m_softStackLimit);
}
void** addressOfSoftStackLimit() { return &m_softStackLimit; }
#if ENABLE(C_LOOP)
void* cloopStackLimit() { return m_cloopStackLimit; }
void setCLoopStackLimit(void* newStackLimit);
ALWAYS_INLINE void* currentCLoopStackPointer() const { return m_cloopStack.currentStackPointer(); }
CLoopStack& cloopStack() { return m_cloopStack; }
const CLoopStack& cloopStack() const { return m_cloopStack; }
static constexpr ptrdiff_t offsetOfCLoopStack()
{
return OBJECT_OFFSETOF(StackManager, m_cloopStack);
}
#endif
VM& vm();
static constexpr uintptr_t StopRequestMarkerValue = std::numeric_limits<uintptr_t>::max();
private:
static ALWAYS_INLINE void* stopRequestMarker() { return reinterpret_cast<void*>(StopRequestMarkerValue); }
Atomic<void*> m_trapAwareSoftStackLimit { nullptr };
void* m_softStackLimit { nullptr };
Lock m_mirrorLock;
SentinelLinkedList<Mirror, BasicRawSentinelNode<Mirror>> m_mirrors WTF_GUARDED_BY_LOCK(m_mirrorLock);
#if ENABLE(C_LOOP)
void* m_cloopStackLimit { nullptr };
// m_cloopStack must be declared after the m_mirrors list because CLoopStack
// initialization requires calling setCLoopStackLimit() which relies on
// m_mirrors (above) being already initialized.
CLoopStack m_cloopStack;
#endif
friend class LLIntOffsetsExtractor;
};
static_assert(sizeof(Atomic<void*>) == sizeof(void*), "m_trapAwareSoftStackLimit relies on this invariant");
} // namespace JSC
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