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[libc++] Avoid using timespec when it might not be available

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Summary:
The type timespec is unconditionally used in __threading_support.
Since the C library is only required to provide it in C11, this might
cause problems for platforms with external thread porting layer (i.e.
when _LIBCPP_HAS_THREAD_API_EXTERNAL is defined) with pre-C11
C libraries.

In our downstream port of libc++ we used to provide a definition of
timespec in __external_threading, but this solution is not ideal
because timespec is not a reserved name.

This patch renames timespec into __libcpp_timespec_t in the
thread-related parts of libc++. For all cases except external
threading this type is an alias for ::timespec (and no functional
changes are intended).

In case of external threading it is expected that the
__external_threading header will either provide a similar typedef (if
timespec is available in the vendor's C library) or provide a
definition of __libcpp_timespec_t compatible with POSIX timespec.

Reviewers: ldionne, mclow.lists, EricWF

Reviewed By: ldionne

Subscribers: dexonsmith, libcxx-commits, christof, carwil

Tags: #libc

Differential Revision: https://reviews.llvm.org/D63328

llvm-svn: 364012
This commit is contained in:
Mikhail Maltsev 2019-06-21 08:33:47 +00:00
parent dea9d57d95
commit cfdc7f0d7e
3 changed files with 7 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
libcxx/include/__threading_support
View file

@ -22,6 +22,8 @@
# include <__external_threading>
#elif !defined(_LIBCPP_HAS_NO_THREADS)
typedef ::timespec __libcpp_timespec_t;
#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
# include <pthread.h>
# include <sched.h>
@ -148,7 +150,7 @@ int __libcpp_condvar_wait(__libcpp_condvar_t* __cv, __libcpp_mutex_t* __m);
_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
timespec *__ts);
__libcpp_timespec_t *__ts);
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_condvar_destroy(__libcpp_condvar_t* __cv);
@ -287,7 +289,7 @@ int __libcpp_condvar_wait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m)
}
int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
timespec *__ts)
__libcpp_timespec_t *__ts)
{
return pthread_cond_timedwait(__cv, __m, __ts);
}
@ -356,7 +358,7 @@ void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
{
using namespace chrono;
seconds __s = duration_cast<seconds>(__ns);
timespec __ts;
__libcpp_timespec_t __ts;
typedef decltype(__ts.tv_sec) ts_sec;
_LIBCPP_CONSTEXPR ts_sec __ts_sec_max = numeric_limits<ts_sec>::max();

2
libcxx/src/condition_variable.cpp
View file

@ -60,7 +60,7 @@ condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
nanoseconds d = tp.time_since_epoch();
if (d > nanoseconds(0x59682F000000E941))
d = nanoseconds(0x59682F000000E941);
timespec ts;
__libcpp_timespec_t ts;
seconds s = duration_cast<seconds>(d);
typedef decltype(ts.tv_sec) ts_sec;
_LIBCPP_CONSTEXPR ts_sec ts_sec_max = numeric_limits<ts_sec>::max();

2
libcxx/src/support/win32/thread_win32.cpp
View file

@ -110,7 +110,7 @@ int __libcpp_condvar_wait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m)
}
int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
timespec *__ts)
__libcpp_timespec_t *__ts)
{
using namespace _VSTD::chrono;