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Diffstat (limited to 'include/internal/tsan_assist.h')
| -rw-r--r-- | include/internal/tsan_assist.h | 144 |
1 files changed, 0 insertions, 144 deletions
diff --git a/include/internal/tsan_assist.h b/include/internal/tsan_assist.h deleted file mode 100644 index f8285b1d..00000000 --- a/include/internal/tsan_assist.h +++ /dev/null @@ -1,144 +0,0 @@ -/* - * 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 |