Allow libc++ to be built on systems without POSIX threads
If you're crazy enough to want this sort of thing, then add
-D_LIBCPP_HAS_NO_THREADS to your CXXFLAGS and
--param=additiona_features=libcpp-has-no-threads to your lit commnad line.
http://reviews.llvm.org/D3969
llvm-svn: 217271
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: b3fcc67f8f13cd95d36ed29d0ae1308decb9e099
diff --git a/src/mutex.cpp b/src/mutex.cpp
index 0767897..e56271d 100644
--- a/src/mutex.cpp
+++ b/src/mutex.cpp
@@ -14,6 +14,7 @@
#include "cassert"
_LIBCPP_BEGIN_NAMESPACE_STD
+#ifndef _LIBCPP_HAS_NO_THREADS
const defer_lock_t defer_lock = {};
const try_to_lock_t try_to_lock = {};
@@ -206,18 +207,42 @@
}
}
+#endif // !_LIBCPP_HAS_NO_THREADS
+
// If dispatch_once_f ever handles C++ exceptions, and if one can get to it
// without illegal macros (unexpected macros not beginning with _UpperCase or
// __lowercase), and if it stops spinning waiting threads, then call_once should
// call into dispatch_once_f instead of here. Relevant radar this code needs to
// keep in sync with: 7741191.
+#ifndef _LIBCPP_HAS_NO_THREADS
static pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cv = PTHREAD_COND_INITIALIZER;
+#endif
void
__call_once(volatile unsigned long& flag, void* arg, void(*func)(void*))
{
+#if defined(_LIBCPP_HAS_NO_THREADS)
+ if (flag == 0)
+ {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+ try
+ {
+#endif // _LIBCPP_NO_EXCEPTIONS
+ flag = 1;
+ func(arg);
+ flag = ~0ul;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+ }
+ catch (...)
+ {
+ flag = 0ul;
+ throw;
+ }
+#endif // _LIBCPP_NO_EXCEPTIONS
+ }
+#else // !_LIBCPP_HAS_NO_THREADS
pthread_mutex_lock(&mut);
while (flag == 1)
pthread_cond_wait(&cv, &mut);
@@ -248,6 +273,8 @@
}
else
pthread_mutex_unlock(&mut);
+#endif // !_LIBCPP_HAS_NO_THREADS
+
}
_LIBCPP_END_NAMESPACE_STD