[libcxx] r293197 - Disable thread safety analysis for some functions in __thread_support

[Dimitry Andric via cfe-commits]

I'd like to merge this to the release_40 branch.  Eric, you OK with that?

-Dimitry

> On 26 Jan 2017, at 19:37, Dimitry Andric via cfe-commits <cfe-commits at lists.llvm.org> wrote:
> 
> Author: dim
> Date: Thu Jan 26 12:37:18 2017
> New Revision: 293197
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=293197&view=rev
> Log:
> Disable thread safety analysis for some functions in __thread_support
> 
> Many thread-related libc++ test cases fail on FreeBSD, due to the
> following -Werror warnings:
> 
>    In file included from test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp:17:
>    In file included from include/thread:97:
>    In file included from include/__mutex_base:17:
>    include/__threading_support:222:1: error: mutex '__m' is still held at the end of function [-Werror,-Wthread-safety-analysis]
>    }
>    ^
>    include/__threading_support:221:10: note: mutex acquired here
>      return pthread_mutex_lock(__m);
>             ^
>    include/__threading_support:231:10: error: releasing mutex '__m' that was not held [-Werror,-Wthread-safety-analysis]
>      return pthread_mutex_unlock(__m);
>             ^
>    include/__threading_support:242:1: error: mutex '__m' is still held at the end of function [-Werror,-Wthread-safety-analysis]
>    }
>    ^
>    include/__threading_support:241:10: note: mutex acquired here
>      return pthread_mutex_lock(__m);
>             ^
>    include/__threading_support:251:10: error: releasing mutex '__m' that was not held [-Werror,-Wthread-safety-analysis]
>      return pthread_mutex_unlock(__m);
>             ^
>    include/__threading_support:272:10: error: calling function 'pthread_cond_wait' requires holding mutex '__m' exclusively [-Werror,-Wthread-safety-analysis]
>      return pthread_cond_wait(__cv, __m);
>             ^
>    include/__threading_support:278:10: error: calling function 'pthread_cond_timedwait' requires holding mutex '__m' exclusively [-Werror,-Wthread-safety-analysis]
>      return pthread_cond_timedwait(__cv, __m, __ts);
>             ^
>    6 errors generated.
> 
> This is because on FreeBSD, the pthread functions have lock annotations.
> Since the functions in __thread_support are internal to libc++ only, add
> no_thread_safety_analysis attributes to suppress these warnings.
> 
> Reviewers: mclow.lists, EricWF, delesley, aaron.ballman
> Reviewed By: aaron.ballman
> Subscribers: ed, aaron.ballman, joerg, emaste, cfe-commits
> Differential Revision: https://reviews.llvm.org/D28520
> 
> Modified:
>    libcxx/trunk/include/__threading_support
> 
> Modified: libcxx/trunk/include/__threading_support
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__threading_support?rev=293197&r1=293196&r2=293197&view=diff
> ==============================================================================
> --- libcxx/trunk/include/__threading_support (original)
> +++ libcxx/trunk/include/__threading_support Thu Jan 26 12:37:18 2017
> @@ -40,6 +40,12 @@
> #define _LIBCPP_THREAD_ABI_VISIBILITY inline _LIBCPP_INLINE_VISIBILITY
> #endif
> 
> +#if defined(__FreeBSD__) && defined(__clang__) && __has_attribute(no_thread_safety_analysis)
> +#define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis))
> +#else
> +#define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> +#endif
> +
> _LIBCPP_BEGIN_NAMESPACE_STD
> 
> #if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
> @@ -102,25 +108,25 @@ typedef DWORD __libcpp_tls_key;
> _LIBCPP_THREAD_ABI_VISIBILITY
> int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m);
> 
> _LIBCPP_THREAD_ABI_VISIBILITY
> int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> int __libcpp_mutex_lock(__libcpp_mutex_t *__m);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> int __libcpp_mutex_unlock(__libcpp_mutex_t *__m);
> 
> _LIBCPP_THREAD_ABI_VISIBILITY
> @@ -133,10 +139,10 @@ int __libcpp_condvar_signal(__libcpp_con
> _LIBCPP_THREAD_ABI_VISIBILITY
> int __libcpp_condvar_broadcast(__libcpp_condvar_t* __cv);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> int __libcpp_condvar_wait(__libcpp_condvar_t* __cv, __libcpp_mutex_t* __m);
> 
> -_LIBCPP_THREAD_ABI_VISIBILITY
> +_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
> int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
>                                timespec *__ts);
> 
> 
> 
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