We've known for ages that it's not portable to do:
__gthread_mutex_t tmp = __GTHREAD_MUTEX_INIT;
_M_mutex = __tmp;
As PR 53270 shows, the copy assignment now actually fails in C++11
mode on platforms using LinuxThreads, because the mutex has a volatile
member so in C++11 mode the copy assignment operator is deleted.
This patch changes <ext/concurrence.h> to use a
brace-or-equals-initializer for the mutexes and condition variable in
C++11 mode, allowing hppa-linux to bootstrap again and avoiding the
non-portable construct everywhere (this is already the approach we
take for std::mutex etc. in <mutex>). It also makes the same change to
the mutex used in <ext/rope> and fixes a resource leak in that header
by ensuring the mutex is destroyed when it was initialized by
__gthread_mutex_init_function.
PR libstdc++/53270
* include/ext/concurrence.h (__mutex, __recursive_mutex, __cond): Use
NSDMI in C++11 mode.
* include/ext/rope (_Refcount_Base): Likewise. Destroy mutex in
destructor when initialized by function.
Tested x86_64-linux, powerpc64-linux, hppa-linux and x86_64-netbsd (on
the 4.7 branch instead, as netbsd doesn't bootstrap at the moment.)
Committed to trunk.
For 4.6.4 and 4.7.2 I plan to make a less intrusive change, #undef'ing
the __GTHREAD_MUTEX_INIT, _GTHREAD_RECURSIVE_MUTEX_INIT and
__GTHREAD_COND_INIT macros on hppa-linux in C++11 mode, so that the
init functions are used instead. This fixes the bootstrap regression
on hppa-linux without affecting other targets.
commit 62d49cd435f56bc7c433b40bdec010a5e037712b
Author: Jonathan Wakely <[email protected]>
Date: Sat Jun 9 13:10:13 2012 +0100
PR libstdc++/53270
* include/ext/concurrence.h (__mutex, __recursive_mutex, __cond): Use
NSDMI in C++11 mode.
* include/ext/rope (_Refcount_Base): Likewise. Destroy mutex in
destructor when initialized by function.
diff --git a/libstdc++-v3/include/ext/concurrence.h
b/libstdc++-v3/include/ext/concurrence.h
index fc8f63f..22c433b 100644
--- a/libstdc++-v3/include/ext/concurrence.h
+++ b/libstdc++-v3/include/ext/concurrence.h
@@ -143,7 +143,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
class __mutex
{
private:
+#if __GTHREADS && defined __GTHREAD_MUTEX_INIT \
+ && defined __GXX_EXPERIMENTAL_CXX0X__
+ __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
+#else
__gthread_mutex_t _M_mutex;
+#endif
__mutex(const __mutex&);
__mutex& operator=(const __mutex&);
@@ -155,8 +160,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__gthread_active_p())
{
#if defined __GTHREAD_MUTEX_INIT
+# ifndef __GXX_EXPERIMENTAL_CXX0X__
__gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
_M_mutex = __tmp;
+# endif
#else
__GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
@@ -201,7 +208,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
class __recursive_mutex
{
private:
+#if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT \
+ && defined __GXX_EXPERIMENTAL_CXX0X__
+ __gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
+#else
__gthread_recursive_mutex_t _M_mutex;
+#endif
__recursive_mutex(const __recursive_mutex&);
__recursive_mutex& operator=(const __recursive_mutex&);
@@ -213,8 +225,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__gthread_active_p())
{
#if defined __GTHREAD_RECURSIVE_MUTEX_INIT
+# ifndef __GXX_EXPERIMENTAL_CXX0X__
__gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
_M_mutex = __tmp;
+# endif
#else
__GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
@@ -319,7 +333,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
class __cond
{
private:
+#if __GTHREADS && defined __GTHREAD_COND_INIT \
+ && defined __GXX_EXPERIMENTAL_CXX0X__
+ __gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
+#else
__gthread_cond_t _M_cond;
+#endif
__cond(const __cond&);
__cond& operator=(const __cond&);
@@ -331,8 +350,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__gthread_active_p())
{
#if defined __GTHREAD_COND_INIT
+# ifndef __GXX_EXPERIMENTAL_CXX0X__
__gthread_cond_t __tmp = __GTHREAD_COND_INIT;
_M_cond = __tmp;
+# endif
#else
__GTHREAD_COND_INIT_FUNCTION(&_M_cond);
#endif
diff --git a/libstdc++-v3/include/ext/rope b/libstdc++-v3/include/ext/rope
index 5e82811..15cb423 100644
--- a/libstdc++-v3/include/ext/rope
+++ b/libstdc++-v3/include/ext/rope
@@ -458,13 +458,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
volatile _RC_t _M_ref_count;
// Constructor
+#if defined __GTHREAD_MUTEX_INIT && defined __GXX_EXPERIMENTAL_CXX0X__
+ __gthread_mutex_t _M_ref_count_lock = __GTHREAD_MUTEX_INIT;
+#else
__gthread_mutex_t _M_ref_count_lock;
+#endif
_Refcount_Base(_RC_t __n) : _M_ref_count(__n), _M_ref_count_lock()
{
#ifdef __GTHREAD_MUTEX_INIT
+# ifndef __GXX_EXPERIMENTAL_CXX0X__
__gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
_M_ref_count_lock = __tmp;
+# endif
#elif defined(__GTHREAD_MUTEX_INIT_FUNCTION)
__GTHREAD_MUTEX_INIT_FUNCTION (&_M_ref_count_lock);
#else
@@ -472,6 +478,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif
}
+#ifndef __GTHREAD_MUTEX_INIT
+ ~_Refcount_Base()
+ { __gthread_mutex_destroy(&_M_ref_count_lock); }
+#endif
+
void
_M_incr()
{
