weex_core/Source/include/wtf/FastTLS.h

/*
 * 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

#if HAVE(FAST_TLS)

#include <pthread.h>
#include <System/pthread_machdep.h>

namespace WTF {

// __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY0 is taken by bmalloc, so WTF's KEY0 maps to the
// system's KEY1.
#define WTF_FAST_TLS_KEY0 __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY1
#define WTF_FAST_TLS_KEY1 __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY2
#define WTF_FAST_TLS_KEY2 __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY3
#define WTF_FAST_TLS_KEY3 __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY4

// NOTE: We should manage our use of these keys here. If you want to use a key for something,
// put a #define in here to give your key a symbolic name. This ensures that we don't
// accidentally use the same key for more than one thing.

#define WTF_THREAD_DATA_KEY WTF_FAST_TLS_KEY0
#define WTF_TESTING_KEY WTF_FAST_TLS_KEY3

#if ENABLE(FAST_TLS_JIT)
// Below is the code that the JIT will emit.

#if CPU(X86_64)
inline uintptr_t loadFastTLS(unsigned offset)
{
    uintptr_t result;
    asm volatile(
        "movq %%gs:%1, %0"
        : "=r"(result)
        : "r"(offset)
        : "memory");
    return result;
}
#elif CPU(ARM64)
inline uintptr_t loadFastTLS(unsigned passedOffset)
{
    uintptr_t result;
    uintptr_t offset = passedOffset;
    asm volatile(
        "mrs %0, TPIDRRO_EL0\n\t"
        "and %0, %0, #0xfffffffffffffff8\n\t"
        "ldr %0, [%0, %1]"
        : "=r"(result)
        : "r"(offset)
        : "memory");
    return result;
}
#else
#error "Bad architecture"
#endif
#endif // ENABLE(FAST_TLS_JIT)

inline unsigned fastTLSOffsetForKey(unsigned long slot)
{
    return slot * sizeof(void*);
}

} // namespace WTF

using WTF::fastTLSOffsetForKey;

#if ENABLE(FAST_TLS_JIT)
using WTF::loadFastTLS;
#endif

#endif // HAVE(FAST_TLS)