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-rw-r--r--thirdparty/internal/tsan_assist.h144
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-/*
- * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
- *
- * Licensed under the Apache License 2.0 (the "License"). You may not use
- * this file except in compliance with the License. You can obtain a copy
- * in the file LICENSE in the source distribution or at
- * https://www.openssl.org/source/license.html
- */
-
-/*
- * Contemporary compilers implement lock-free atomic memory access
- * primitives that facilitate writing "thread-opportunistic" or even real
- * multi-threading low-overhead code. "Thread-opportunistic" is when
- * exact result is not required, e.g. some statistics, or execution flow
- * doesn't have to be unambiguous. Simplest example is lazy "constant"
- * initialization when one can synchronize on variable itself, e.g.
- *
- * if (var == NOT_YET_INITIALIZED)
- * var = function_returning_same_value();
- *
- * This does work provided that loads and stores are single-instruction
- * operations (and integer ones are on *all* supported platforms), but
- * it upsets Thread Sanitizer. Suggested solution is
- *
- * if (tsan_load(&var) == NOT_YET_INITIALIZED)
- * tsan_store(&var, function_returning_same_value());
- *
- * Production machine code would be the same, so one can wonder why
- * bother. Having Thread Sanitizer accept "thread-opportunistic" code
- * allows to move on trouble-shooting real bugs.
- *
- * Resolving Thread Sanitizer nits was the initial purpose for this module,
- * but it was later extended with more nuanced primitives that are useful
- * even in "non-opportunistic" scenarios. Most notably verifying if a shared
- * structure is fully initialized and bypassing the initialization lock.
- * It's suggested to view macros defined in this module as "annotations" for
- * thread-safe lock-free code, "Thread-Safe ANnotations"...
- *
- * It's assumed that ATOMIC_{LONG|INT}_LOCK_FREE are assigned same value as
- * ATOMIC_POINTER_LOCK_FREE. And check for >= 2 ensures that corresponding
- * code is inlined. It should be noted that statistics counters become
- * accurate in such case.
- *
- * Special note about TSAN_QUALIFIER. It might be undesired to use it in
- * a shared header. Because whether operation on specific variable or member
- * is atomic or not might be irrelevant in other modules. In such case one
- * can use TSAN_QUALIFIER in cast specifically when it has to count.
- */
-
-#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
- && !defined(__STDC_NO_ATOMICS__)
-# include <stdatomic.h>
-
-# if defined(ATOMIC_POINTER_LOCK_FREE) \
- && ATOMIC_POINTER_LOCK_FREE >= 2
-# define TSAN_QUALIFIER _Atomic
-# define tsan_load(ptr) atomic_load_explicit((ptr), memory_order_relaxed)
-# define tsan_store(ptr, val) atomic_store_explicit((ptr), (val), memory_order_relaxed)
-# define tsan_counter(ptr) atomic_fetch_add_explicit((ptr), 1, memory_order_relaxed)
-# define tsan_decr(ptr) atomic_fetch_add_explicit((ptr), -1, memory_order_relaxed)
-# define tsan_ld_acq(ptr) atomic_load_explicit((ptr), memory_order_acquire)
-# define tsan_st_rel(ptr, val) atomic_store_explicit((ptr), (val), memory_order_release)
-# endif
-
-#elif defined(__GNUC__) && defined(__ATOMIC_RELAXED)
-
-# if defined(__GCC_ATOMIC_POINTER_LOCK_FREE) \
- && __GCC_ATOMIC_POINTER_LOCK_FREE >= 2
-# define TSAN_QUALIFIER volatile
-# define tsan_load(ptr) __atomic_load_n((ptr), __ATOMIC_RELAXED)
-# define tsan_store(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_RELAXED)
-# define tsan_counter(ptr) __atomic_fetch_add((ptr), 1, __ATOMIC_RELAXED)
-# define tsan_decr(ptr) __atomic_fetch_add((ptr), -1, __ATOMIC_RELAXED)
-# define tsan_ld_acq(ptr) __atomic_load_n((ptr), __ATOMIC_ACQUIRE)
-# define tsan_st_rel(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_RELEASE)
-# endif
-
-#elif defined(_MSC_VER) && _MSC_VER>=1200 \
- && (defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \
- defined(_M_ARM64) || (defined(_M_ARM) && _M_ARM >= 7 && !defined(_WIN32_WCE)))
-/*
- * There is subtle dependency on /volatile:<iso|ms> command-line option.
- * "ms" implies same semantic as memory_order_acquire for loads and
- * memory_order_release for stores, while "iso" - memory_order_relaxed for
- * either. Real complication is that defaults are different on x86 and ARM.
- * There is explanation for that, "ms" is backward compatible with earlier
- * compiler versions, while multi-processor ARM can be viewed as brand new
- * platform to MSC and its users, and with non-relaxed semantic taking toll
- * with additional instructions and penalties, it kind of makes sense to
- * default to "iso"...
- */
-# define TSAN_QUALIFIER volatile
-# if defined(_M_ARM) || defined(_M_ARM64)
-# define _InterlockedExchangeAdd _InterlockedExchangeAdd_nf
-# pragma intrinsic(_InterlockedExchangeAdd_nf)
-# pragma intrinsic(__iso_volatile_load32, __iso_volatile_store32)
-# ifdef _WIN64
-# define _InterlockedExchangeAdd64 _InterlockedExchangeAdd64_nf
-# pragma intrinsic(_InterlockedExchangeAdd64_nf)
-# pragma intrinsic(__iso_volatile_load64, __iso_volatile_store64)
-# define tsan_load(ptr) (sizeof(*(ptr)) == 8 ? __iso_volatile_load64(ptr) \
- : __iso_volatile_load32(ptr))
-# define tsan_store(ptr, val) (sizeof(*(ptr)) == 8 ? __iso_volatile_store64((ptr), (val)) \
- : __iso_volatile_store32((ptr), (val)))
-# else
-# define tsan_load(ptr) __iso_volatile_load32(ptr)
-# define tsan_store(ptr, val) __iso_volatile_store32((ptr), (val))
-# endif
-# else
-# define tsan_load(ptr) (*(ptr))
-# define tsan_store(ptr, val) (*(ptr) = (val))
-# endif
-# pragma intrinsic(_InterlockedExchangeAdd)
-# ifdef _WIN64
-# pragma intrinsic(_InterlockedExchangeAdd64)
-# define tsan_counter(ptr) (sizeof(*(ptr)) == 8 ? _InterlockedExchangeAdd64((ptr), 1) \
- : _InterlockedExchangeAdd((ptr), 1))
-# define tsan_decr(ptr) (sizeof(*(ptr)) == 8 ? _InterlockedExchangeAdd64((ptr), -1) \
- : _InterlockedExchangeAdd((ptr), -1))
-# else
-# define tsan_counter(ptr) _InterlockedExchangeAdd((ptr), 1)
-# define tsan_decr(ptr) _InterlockedExchangeAdd((ptr), -1)
-# endif
-# if !defined(_ISO_VOLATILE)
-# define tsan_ld_acq(ptr) (*(ptr))
-# define tsan_st_rel(ptr, val) (*(ptr) = (val))
-# endif
-
-#endif
-
-#ifndef TSAN_QUALIFIER
-
-# define TSAN_QUALIFIER volatile
-# define tsan_load(ptr) (*(ptr))
-# define tsan_store(ptr, val) (*(ptr) = (val))
-# define tsan_counter(ptr) ((*(ptr))++)
-# define tsan_decr(ptr) ((*(ptr))--)
-/*
- * Lack of tsan_ld_acq and tsan_ld_rel means that compiler support is not
- * sophisticated enough to support them. Code that relies on them should be
- * protected with #ifdef tsan_ld_acq with locked fallback.
- */
-
-#endif