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/*
* Copyright (C) 2018-2024 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 "Instruction.h"
#include "Opcode.h"
#include "UnlinkedMetadataTable.h"
#include "ValueProfile.h"
#include <wtf/RefCounted.h>
#include <wtf/TZoneMalloc.h>
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
class CodeBlock;
// MetadataTable has a bit strange memory layout for LLInt optimization.
// [ValueProfile][UnlinkedMetadataTable::LinkingData][MetadataTableOffsets][MetadataContent]
// ^
// The pointer of MetadataTable points at this address.
class MetadataTable {
WTF_MAKE_TZONE_ALLOCATED(MetadataTable);
WTF_MAKE_NONCOPYABLE(MetadataTable);
friend class LLIntOffsetsExtractor;
friend class UnlinkedMetadataTable;
public:
~MetadataTable();
template<typename Metadata>
ALWAYS_INLINE Metadata* get()
{
auto opcodeID = Metadata::opcodeID;
ASSERT(opcodeID < NUMBER_OF_BYTECODE_WITH_METADATA);
uintptr_t ptr = std::bit_cast<uintptr_t>(getWithoutAligning(opcodeID));
ptr = roundUpToMultipleOf(alignof(Metadata), ptr);
return std::bit_cast<Metadata*>(ptr);
}
template<typename Op, typename Functor>
ALWAYS_INLINE void forEach(const Functor& func)
{
auto* metadata = get<typename Op::Metadata>();
auto* end = std::bit_cast<typename Op::Metadata*>(getWithoutAligning(Op::opcodeID + 1));
for (; metadata < end; ++metadata)
func(*metadata);
}
template<typename Functor>
ALWAYS_INLINE void forEachValueProfile(const Functor& func)
{
// We could do a checked multiply here but if it overflows we'd just not look at any value profiles so it's probably not worth it.
int lastValueProfileOffset = -unlinkedMetadata()->m_numValueProfiles;
for (int i = -1; i >= lastValueProfileOffset; --i)
func(valueProfilesEnd()[i]);
}
ValueProfile* valueProfilesEnd()
{
return reinterpret_cast_ptr<ValueProfile*>(&linkingData());
}
ValueProfile& valueProfileForOffset(unsigned profileOffset)
{
ASSERT(profileOffset <= unlinkedMetadata()->m_numValueProfiles);
return valueProfilesEnd()[-static_cast<ptrdiff_t>(profileOffset)];
}
size_t sizeInBytesForGC();
void ref()
{
++linkingData().refCount;
}
void deref()
{
if (!--linkingData().refCount) {
// Setting refCount to 1 here prevents double delete within the destructor but not from another thread
// since such a thread could have ref'ed this object long after it had been deleted. This is consistent
// with ThreadSafeRefCounted.h, see webkit.org/b/201576 for the reasoning.
linkingData().refCount = 1;
MetadataTable::destroy(this);
return;
}
}
unsigned refCount() const
{
return linkingData().refCount;
}
unsigned hasOneRef() const
{
return refCount() == 1;
}
template <typename Opcode>
uintptr_t offsetInMetadataTable(const Opcode& opcode)
{
uintptr_t baseTypeOffset = is32Bit() ? offsetTable32()[Opcode::opcodeID] : offsetTable16()[Opcode::opcodeID];
baseTypeOffset = roundUpToMultipleOf(alignof(typename Opcode::Metadata), baseTypeOffset);
return baseTypeOffset + sizeof(typename Opcode::Metadata) * opcode.m_metadataID;
}
void validate() const;
RefPtr<UnlinkedMetadataTable> unlinkedMetadata() const { return static_reference_cast<UnlinkedMetadataTable>(linkingData().unlinkedMetadata); }
SUPPRESS_ASAN bool isDestroyed() const
{
uintptr_t unlinkedMetadataPtr = *std::bit_cast<uintptr_t*>(&linkingData().unlinkedMetadata);
return !unlinkedMetadataPtr;
}
private:
MetadataTable(UnlinkedMetadataTable&);
UnlinkedMetadataTable::Offset16* offsetTable16() const { return std::bit_cast<UnlinkedMetadataTable::Offset16*>(this); }
UnlinkedMetadataTable::Offset32* offsetTable32() const { return std::bit_cast<UnlinkedMetadataTable::Offset32*>(std::bit_cast<uint8_t*>(this) + UnlinkedMetadataTable::s_offset16TableSize); }
size_t totalSize() const
{
return unlinkedMetadata()->m_numValueProfiles * sizeof(ValueProfile) + sizeof(UnlinkedMetadataTable::LinkingData) + getOffset(UnlinkedMetadataTable::s_offsetTableEntries - 1);
}
UnlinkedMetadataTable::LinkingData& linkingData() const
{
return *std::bit_cast<UnlinkedMetadataTable::LinkingData*>((std::bit_cast<uint8_t*>(this) - sizeof(UnlinkedMetadataTable::LinkingData)));
}
void* buffer() { return this; }
// Offset of zero means that the 16 bit table is not in use.
bool is32Bit() const { return !offsetTable16()[0]; }
ALWAYS_INLINE unsigned getOffset(unsigned i) const
{
unsigned offset = offsetTable16()[i];
if (offset)
return offset;
return offsetTable32()[i];
}
ALWAYS_INLINE uint8_t* getWithoutAligning(unsigned i)
{
return std::bit_cast<uint8_t*>(this) + getOffset(i);
}
static void destroy(MetadataTable*);
};
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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