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Reland "[mips][compiler-rt] Provide 64bit atomic add and sub"
r318733 introduced a build failure for native MIPS32 systems for xray due to the lack of __sync_fetch_and_add / __syn_fetch_and_sub support. This patch extends the existing support providing atomics so that xray can be successfully built. The initial patch was reverted in r321292, as I suspected it may have caused the buildbot failure. Another patch in the updates the bot fetched caused the test failures which was reverted. Reviewers: atanasyan, dberris Differential Revision: https://reviews.llvm.org/D40385 llvm-svn: 321383
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Simon Dardis
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Dec 22, 2017
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compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang_mips.h
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| //===-- sanitizer_atomic_clang_mips.h ---------------------------*- C++ -*-===// | ||
| // | ||
| // The LLVM Compiler Infrastructure | ||
| // | ||
| // This file is distributed under the University of Illinois Open Source | ||
| // License. See LICENSE.TXT for details. | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
| // | ||
| // This file is a part of ThreadSanitizer/AddressSanitizer runtime. | ||
| // Not intended for direct inclusion. Include sanitizer_atomic.h. | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
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| #ifndef SANITIZER_ATOMIC_CLANG_MIPS_H | ||
| #define SANITIZER_ATOMIC_CLANG_MIPS_H | ||
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| namespace __sanitizer { | ||
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| // MIPS32 does not support atomics > 4 bytes. To address this lack of | ||
| // functionality, the sanitizer library provides helper methods which use an | ||
| // internal spin lock mechanism to emulate atomic oprations when the size is | ||
| // 8 bytes. | ||
| static void __spin_lock(volatile int *lock) { | ||
| while (__sync_lock_test_and_set(lock, 1)) | ||
| while (*lock) { | ||
| } | ||
| } | ||
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| static void __spin_unlock(volatile int *lock) { __sync_lock_release(lock); } | ||
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| // Make sure the lock is on its own cache line to prevent false sharing. | ||
| // Put it inside a struct that is aligned and padded to the typical MIPS | ||
| // cacheline which is 32 bytes. | ||
| static struct { | ||
| int lock; | ||
| char pad[32 - sizeof(int)]; | ||
| } __attribute__((aligned(32))) lock = {0, {0}}; | ||
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| template <> | ||
| INLINE atomic_uint64_t::Type atomic_fetch_add(volatile atomic_uint64_t *ptr, | ||
| atomic_uint64_t::Type val, | ||
| memory_order mo) { | ||
| DCHECK(mo & | ||
| (memory_order_relaxed | memory_order_releasae | memory_order_seq_cst)); | ||
| DCHECK(!((uptr)ptr % sizeof(*ptr))); | ||
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| atomic_uint64_t::Type ret; | ||
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| __spin_lock(&lock.lock); | ||
| ret = *(const_cast<atomic_uint64_t::Type volatile *>(&ptr->val_dont_use)); | ||
| ptr->val_dont_use = ret + val; | ||
| __spin_unlock(&lock.lock); | ||
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| return ret; | ||
| } | ||
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| template <> | ||
| INLINE atomic_uint64_t::Type atomic_fetch_sub(volatile atomic_uint64_t *ptr, | ||
| atomic_uint64_t::Type val, | ||
| memory_order mo) { | ||
| return atomic_fetch_add(ptr, -val, mo); | ||
| } | ||
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| template <> | ||
| INLINE bool atomic_compare_exchange_strong(volatile atomic_uint64_t *ptr, | ||
| atomic_uint64_t::Type *cmp, | ||
| atomic_uint64_t::Type xchg, | ||
| memory_order mo) { | ||
| DCHECK(mo & | ||
| (memory_order_relaxed | memory_order_releasae | memory_order_seq_cst)); | ||
| DCHECK(!((uptr)ptr % sizeof(*ptr))); | ||
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| typedef atomic_uint64_t::Type Type; | ||
| Type cmpv = *cmp; | ||
| Type prev; | ||
| bool ret = false; | ||
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| __spin_lock(&lock.lock); | ||
| prev = *(const_cast<Type volatile *>(&ptr->val_dont_use)); | ||
| if (prev == cmpv) { | ||
| ret = true; | ||
| ptr->val_dont_use = xchg; | ||
| } | ||
| __spin_unlock(&lock.lock); | ||
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| return ret; | ||
| } | ||
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| template <> | ||
| INLINE atomic_uint64_t::Type atomic_load(const volatile atomic_uint64_t *ptr, | ||
| memory_order mo) { | ||
| DCHECK(mo & | ||
| (memory_order_relaxed | memory_order_releasae | memory_order_seq_cst)); | ||
| DCHECK(!((uptr)ptr % sizeof(*ptr))); | ||
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| atomic_uint64_t::Type zero = 0; | ||
| volatile atomic_uint64_t *Newptr = | ||
| const_cast<volatile atomic_uint64_t *>(ptr); | ||
| return atomic_fetch_add(Newptr, zero, mo); | ||
| } | ||
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| template <> | ||
| INLINE void atomic_store(volatile atomic_uint64_t *ptr, atomic_uint64_t::Type v, | ||
| memory_order mo) { | ||
| DCHECK(mo & | ||
| (memory_order_relaxed | memory_order_releasae | memory_order_seq_cst)); | ||
| DCHECK(!((uptr)ptr % sizeof(*ptr))); | ||
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| __spin_lock(&lock.lock); | ||
| ptr->val_dont_use = v; | ||
| __spin_unlock(&lock.lock); | ||
| } | ||
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| } // namespace __sanitizer | ||
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| #endif // SANITIZER_ATOMIC_CLANG_MIPS_H | ||
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