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/*
* Copyright (C) 2017 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 "JSCJSValue.h"
#include <wtf/AccessibleAddress.h>
#include <wtf/StdLibExtras.h>
namespace JSC {
class JSCell;
class NativeCallee;
class CalleeBits {
public:
CalleeBits() = default;
CalleeBits(int64_t value)
#if USE(JSVALUE64)
: m_ptr { reinterpret_cast<void*>(value) }
#elif USE(JSVALUE32_64)
: m_ptr { reinterpret_cast<void*>(JSValue::decode(value).payload()) }
, m_tag { JSValue::decode(value).tag() }
#endif
{ }
CalleeBits& operator=(JSCell* cell)
{
m_ptr = cell;
#if USE(JSVALUE32_64)
m_tag = JSValue::CellTag;
#endif
ASSERT(isCell());
return *this;
}
#if USE(JSVALUE32_64)
static EncodedJSValue encodeNullCallee()
{
return JSValue::encode(jsNull());
}
static EncodedJSValue encodeJSCallee(const JSCell* cell)
{
if (!cell)
return encodeNullCallee();
return JSValue::encode(JSValue(cell));
}
static EncodedJSValue encodeBoxedNativeCallee(void* boxedCallee)
{
if (!boxedCallee)
return encodeNullCallee();
EncodedValueDescriptor ret;
ret.asBits.tag = JSValue::NativeCalleeTag;
ret.asBits.payload = reinterpret_cast<intptr_t>(boxedCallee);
return bitwise_cast<EncodedJSValue>(ret);
}
#elif USE(JSVALUE64)
static EncodedJSValue encodeNullCallee()
{
return reinterpret_cast<EncodedJSValue>(nullptr);
}
static EncodedJSValue encodeJSCallee(const JSCell* cell)
{
if (!cell)
return encodeNullCallee();
return reinterpret_cast<EncodedJSValue>(cell);
}
static EncodedJSValue encodeBoxedNativeCallee(void* boxedCallee)
{
return reinterpret_cast<EncodedJSValue>(boxedCallee);
}
#else
#error "Unsupported configuration"
#endif
static EncodedJSValue encodeNativeCallee(NativeCallee* callee)
{
if (!callee)
return encodeNullCallee();
return encodeBoxedNativeCallee(boxNativeCallee(callee));
}
static void* boxNativeCalleeIfExists(NativeCallee* callee)
{
if (callee)
return boxNativeCallee(callee);
return nullptr;
}
static void* boxNativeCallee(NativeCallee* callee)
{
#if USE(JSVALUE64)
CalleeBits result { static_cast<int64_t>((bitwise_cast<uintptr_t>(callee) - lowestAccessibleAddress()) | JSValue::NativeCalleeTag) };
ASSERT(result.isNativeCallee());
return result.rawPtr();
#elif USE(JSVALUE32_64)
return bitwise_cast<void*>(bitwise_cast<uintptr_t>(callee) - lowestAccessibleAddress());
#endif
}
bool isNativeCallee() const
{
#if USE(JSVALUE64)
return (reinterpret_cast<uintptr_t>(m_ptr) & JSValue::NativeCalleeMask) == JSValue::NativeCalleeTag;
#elif USE(JSVALUE32_64)
return m_tag == JSValue::NativeCalleeTag;
#endif
}
bool isCell() const { return !isNativeCallee(); }
JSCell* asCell() const
{
ASSERT(!isNativeCallee());
return static_cast<JSCell*>(m_ptr);
}
NativeCallee* asNativeCallee() const
{
ASSERT(isNativeCallee());
#if USE(JSVALUE64)
return bitwise_cast<NativeCallee*>(static_cast<uintptr_t>(bitwise_cast<uintptr_t>(m_ptr) & ~JSValue::NativeCalleeTag) + lowestAccessibleAddress());
#elif USE(JSVALUE32_64)
return bitwise_cast<NativeCallee*>(bitwise_cast<uintptr_t>(m_ptr) + lowestAccessibleAddress());
#endif
}
void* rawPtr() const { return m_ptr; }
private:
void* m_ptr { nullptr };
#if USE(JSVALUE32_64)
uint32_t m_tag { JSValue::EmptyValueTag };
#endif
};
} // namespace JSC
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