dim updated this revision to Diff 85440.
dim added a comment.
In https://reviews.llvm.org/D28520#653360, @aaron.ballman wrote:
> In https://reviews.llvm.org/D28520#652607, @dim wrote:
>
> >
>
[...]
>> I'm really open to any variant, as long as something that works can get in
>> before the 4.0.0 release. :)
>
> I feel like there's still some confusion here (likely on my part). DeLesley
> was asking if there was a way to turn this off for everyone *except* FreeBSD
> (that is user-controllable), but your code turns it off specifically *for*
> FreeBSD with no option to enable. The part that has me confused is that
> FreeBSD is annotating their functionality specifically to enable thread
> safety checking; it seems like turning that checking off rather than
> supporting it is the wrong way to go. I think that may be why DeLesley was
> saying to disable the functionality for non-FreeBSD systems while still
> honoring it on FreeBSD, but if I'm confused, hopefully he'll clarify.
Ok, so let's go back to the previous variant, but with conditionals to be able
to turn checking on, if so desired, using
`_LIBCPP_ENABLE_THREAD_SAFETY_ATTRIBUTE`. Checking is on by default for
FreeBSD only, but can still be disabled explicitly by defining
`_LIBCPP_DISABLE_THREAD_SAFETY_ATTRIBUTE`.
https://reviews.llvm.org/D28520
Files:
include/__threading_support
Index: include/__threading_support
===================================================================
--- include/__threading_support
+++ include/__threading_support
@@ -40,14 +40,30 @@
#define _LIBCPP_THREAD_ABI_VISIBILITY inline _LIBCPP_INLINE_VISIBILITY
#endif
+#if defined(__FreeBSD__) && !defined(_LIBCPP_DISABLE_THREAD_SAFETY_ATTRIBUTE) && \
+ !defined(_LIBCPP_ENABLE_THREAD_SAFETY_ATTRIBUTE)
+# define _LIBCPP_ENABLE_THREAD_SAFETY_ATTRIBUTE
+#endif
+
+#ifndef _LIBCPP_THREAD_SAFETY_ATTRIBUTE
+# if defined(__clang__) && __has_attribute(acquire_capability) && \
+ defined(_LIBCPP_ENABLE_THREAD_SAFETY_ATTRIBUTE)
+# define _LIBCPP_THREAD_SAFETY_ATTRIBUTE(x) __attribute__((x))
+# else
+# define _LIBCPP_THREAD_SAFETY_ATTRIBUTE(x)
+# endif
+#endif
+
_LIBCPP_BEGIN_NAMESPACE_STD
#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
// Mutex
-typedef pthread_mutex_t __libcpp_mutex_t;
+typedef pthread_mutex_t __libcpp_mutex_t
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(capability("mutex"));
#define _LIBCPP_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
-typedef pthread_mutex_t __libcpp_recursive_mutex_t;
+typedef pthread_mutex_t __libcpp_recursive_mutex_t
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(capability("mutex"));
// Condition Variable
typedef pthread_cond_t __libcpp_condvar_t;
@@ -71,10 +87,12 @@
#define _LIBCPP_TLS_DESTRUCTOR_CC
#else
// Mutex
-typedef SRWLOCK __libcpp_mutex_t;
+typedef SRWLOCK __libcpp_mutex_t
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(capability("mutex"));
#define _LIBCPP_MUTEX_INITIALIZER SRWLOCK_INIT
-typedef CRITICAL_SECTION __libcpp_recursive_mutex_t;
+typedef CRITICAL_SECTION __libcpp_recursive_mutex_t
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(capability("mutex"));
// Condition Variable
typedef CONDITION_VARIABLE __libcpp_condvar_t;
@@ -103,25 +121,31 @@
int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m);
_LIBCPP_THREAD_ABI_VISIBILITY
-int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m);
+int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(acquire_capability(*__m));
_LIBCPP_THREAD_ABI_VISIBILITY
-bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m);
+bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(try_acquire_capability(true, *__m));
_LIBCPP_THREAD_ABI_VISIBILITY
-int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m);
+int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(release_capability(*__m));
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m);
_LIBCPP_THREAD_ABI_VISIBILITY
-int __libcpp_mutex_lock(__libcpp_mutex_t *__m);
+int __libcpp_mutex_lock(__libcpp_mutex_t *__m)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(acquire_capability(*__m));
_LIBCPP_THREAD_ABI_VISIBILITY
-bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m);
+bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(try_acquire_capability(true, *__m));
_LIBCPP_THREAD_ABI_VISIBILITY
-int __libcpp_mutex_unlock(__libcpp_mutex_t *__m);
+int __libcpp_mutex_unlock(__libcpp_mutex_t *__m)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(release_capability(*__m));
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_mutex_destroy(__libcpp_mutex_t *__m);
@@ -134,11 +158,13 @@
int __libcpp_condvar_broadcast(__libcpp_condvar_t* __cv);
_LIBCPP_THREAD_ABI_VISIBILITY
-int __libcpp_condvar_wait(__libcpp_condvar_t* __cv, __libcpp_mutex_t* __m);
+int __libcpp_condvar_wait(__libcpp_condvar_t* __cv, __libcpp_mutex_t* __m)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(requires_capability(*__m));
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
- timespec *__ts);
+ timespec *__ts)
+_LIBCPP_THREAD_SAFETY_ATTRIBUTE(requires_capability(*__m));
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_condvar_destroy(__libcpp_condvar_t* __cv);
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