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//===-- sanitizer_atomic_clang_x86.h ----------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer/AddressSanitizer runtime.
// Not intended for direct inclusion. Include sanitizer_atomic.h.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_ATOMIC_CLANG_X86_H
#define SANITIZER_ATOMIC_CLANG_X86_H
namespace __sanitizer {
inline void proc_yield(int cnt) {
__asm__ __volatile__("" ::: "memory");
for (int i = 0; i < cnt; i++)
__asm__ __volatile__("pause");
__asm__ __volatile__("" ::: "memory");
}
template<typename T>
inline typename T::Type atomic_load(
const volatile T *a, memory_order mo) {
DCHECK(mo & (memory_order_relaxed | memory_order_consume
| memory_order_acquire | memory_order_seq_cst));
DCHECK(!((uptr)a % sizeof(*a)));
typename T::Type v;
if (sizeof(*a) < 8 || sizeof(void*) == 8) {
// Assume that aligned loads are atomic.
if (mo == memory_order_relaxed) {
v = a->val_dont_use;
} else if (mo == memory_order_consume) {
// Assume that processor respects data dependencies
// (and that compiler won't break them).
__asm__ __volatile__("" ::: "memory");
v = a->val_dont_use;
__asm__ __volatile__("" ::: "memory");
} else if (mo == memory_order_acquire) {
__asm__ __volatile__("" ::: "memory");
v = a->val_dont_use;
// On x86 loads are implicitly acquire.
__asm__ __volatile__("" ::: "memory");
} else { // seq_cst
// On x86 plain MOV is enough for seq_cst store.
__asm__ __volatile__("" ::: "memory");
v = a->val_dont_use;
__asm__ __volatile__("" ::: "memory");
}
} else {
// 64-bit load on 32-bit platform.
__asm__ __volatile__(
"movq %1, %%mm0;" // Use mmx reg for 64-bit atomic moves
"movq %%mm0, %0;" // (ptr could be read-only)
"emms;" // Empty mmx state/Reset FP regs
: "=m" (v)
: "m" (a->val_dont_use)
: // mark the mmx registers as clobbered
#ifdef __MMX__
"mm0", "mm1", "mm2", "mm3", "mm4", "mm5", "mm6", "mm7",
#endif // #ifdef __MMX__
"memory");
}
return v;
}
template<typename T>
inline void atomic_store(volatile T *a, typename T::Type v, memory_order mo) {
DCHECK(mo & (memory_order_relaxed | memory_order_release
| memory_order_seq_cst));
DCHECK(!((uptr)a % sizeof(*a)));
if (sizeof(*a) < 8 || sizeof(void*) == 8) {
// Assume that aligned loads are atomic.
if (mo == memory_order_relaxed) {
a->val_dont_use = v;
} else if (mo == memory_order_release) {
// On x86 stores are implicitly release.
__asm__ __volatile__("" ::: "memory");
a->val_dont_use = v;
__asm__ __volatile__("" ::: "memory");
} else { // seq_cst
// On x86 stores are implicitly release.
__asm__ __volatile__("" ::: "memory");
a->val_dont_use = v;
__sync_synchronize();
}
} else {
// 64-bit store on 32-bit platform.
__asm__ __volatile__(
"movq %1, %%mm0;" // Use mmx reg for 64-bit atomic moves
"movq %%mm0, %0;"
"emms;" // Empty mmx state/Reset FP regs
: "=m" (a->val_dont_use)
: "m" (v)
: // mark the mmx registers as clobbered
#ifdef __MMX__
"mm0", "mm1", "mm2", "mm3", "mm4", "mm5", "mm6", "mm7",
#endif // #ifdef __MMX__
"memory");
if (mo == memory_order_seq_cst)
__sync_synchronize();
}
}
} // namespace __sanitizer
#endif // #ifndef SANITIZER_ATOMIC_CLANG_X86_H
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