| 1 | //===--- A platform independent abstraction layer for mutexes ---*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #ifndef LLVM_LIBC_SRC___SUPPORT_THREADS_MUTEX_H |
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| 10 | #define LLVM_LIBC_SRC___SUPPORT_THREADS_MUTEX_H |
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| 11 | |
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| 12 | #include "src/__support/macros/properties/architectures.h" |
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| 13 | |
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| 14 | // Platform independent code will include this header file which pulls |
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| 15 | // the platfrom specific specializations using platform macros. |
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| 16 | // |
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| 17 | // The platform specific specializations should define a class by name |
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| 18 | // Mutex with non-static methods having the following signature: |
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| 19 | // |
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| 20 | // MutexError lock(); |
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| 21 | // MutexError trylock(); |
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| 22 | // MutexError timedlock(...); |
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| 23 | // MutexError unlock(); |
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| 24 | // MutexError reset(); // Used to reset inconsistent robust mutexes. |
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| 25 | // |
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| 26 | // Apart from the above non-static methods, the specializations should |
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| 27 | // also provide few static methods with the following signature: |
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| 28 | // |
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| 29 | // static MutexError init(mtx_t *); |
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| 30 | // static MutexError destroy(mtx_t *); |
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| 31 | // |
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| 32 | // All of the static and non-static methods should ideally be implemented |
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| 33 | // as inline functions so that implementations of public functions can |
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| 34 | // call them without a function call overhead. |
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| 35 | // |
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| 36 | // Another point to keep in mind that is that the libc internally needs a |
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| 37 | // few global locks. So, to avoid static initialization order fiasco, we |
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| 38 | // want the constructors of the Mutex classes to be constexprs. |
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| 39 | |
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| 40 | #if defined(__linux__) |
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| 41 | #include "linux/mutex.h" |
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| 42 | #elif defined(LIBC_TARGET_ARCH_IS_GPU) |
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| 43 | #include "gpu/mutex.h" |
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| 44 | #endif // __linux__ |
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| 45 | |
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| 46 | namespace LIBC_NAMESPACE { |
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| 47 | |
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| 48 | // An RAII class for easy locking and unlocking of mutexes. |
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| 49 | class MutexLock { |
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| 50 | Mutex *mutex; |
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| 51 | |
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| 52 | public: |
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| 53 | explicit MutexLock(Mutex *m) : mutex(m) { mutex->lock(); } |
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| 54 | |
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| 55 | ~MutexLock() { mutex->unlock(); } |
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| 56 | }; |
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| 57 | |
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| 58 | } // namespace LIBC_NAMESPACE |
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| 59 | |
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| 60 | #endif // LLVM_LIBC_SRC___SUPPORT_THREADS_MUTEX_H |
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| 61 | |
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