Fw: [patch] Make std::tr1::shared_ptr thread-safe.
Jonathan Wakely
cow@compsoc.man.ac.uk
Fri Apr 1 23:07:00 GMT 2005
On Sat, Apr 02, 2005 at 12:33:06AM +0200, Paolo Carlini wrote:
> Jonathan Wakely wrote:
>
> >As requested, this is my first patch with the addition of empty critical
> >sections to ensure a consistent view of the ref count.
> >
> >Tested x86_64-unknown-linux-gnu mainline, testing 4.0 now,
> >also tested against the modified Boost tests.
> >
> >
> Thanks Jonathan! If nobody finds even more subtle problems ;), tomorrow
> morning I will regtest it on a couple different multiprocessor machines.
Thanks, I can't do that easily.
Do you have the modified boost tests I posted to the list?
They cover far more than the few tests I've done for gcc.
> Can you possibly post again in one single patch the testsuite changes
> too? (if you can't, no problem, will take that from your first try)
new patch attached
-------------- next part --------------
Index: ChangeLog
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/ChangeLog,v
retrieving revision 1.2948
diff -u -p -r1.2948 ChangeLog
--- ChangeLog 1 Apr 2005 20:20:20 -0000 1.2948
+++ ChangeLog 1 Apr 2005 22:56:29 -0000
@@ -1,3 +1,26 @@
+2005-04-02 Jonathan Wakely <redi@gcc.gnu.org>
+
+ * include/tr1/memory, include/tr1/boost_shared_ptr.h: Use mutex
+ to make _Sp_counted_base::add_ref_lock() thread-safe. Check whether
+ to destroy resources by testing for equality, not inequality. Add
+ empty critical sections to solve memory visibility issues.
+ * testsuite/tr1/2_general_utilities/memory/
+ shared_ptr/cons/auto_ptr_neg.cc: Use dg-excess-errors instead of
+ explicitly listing line numbers which need to be kept in sync.
+ * testsuite/tr1/2_general_utilities/memory/
+ shared_ptr/assign/auto_ptr_neg.cc: Same.
+ * testsuite/tr1/2_general_utilities/memory/
+ shared_ptr/assign/auto_ptr_rvalue_neg.cc: Same.
+ * testsuite/tr1/2_general_utilities/memory/
+ shared_ptr/cons/weak_ptr_expired.cc: Make XFAIL for consistency when
+ -fno-exceptions.
+ * testsuite/tr1/2_general_utilities/memory/
+ enable_shared_from_this/not_shared.cc: Add explanatory comments.
+ * testsuite/tr1/2_general_utilities/memory/
+ enable_shared_from_this/not_shared2.cc: Same.
+ * testsuite/tr1/2_general_utilities/memory/
+ enable_shared_from_this/not_shared3.cc: Same.
+
2005-04-01 Mark Mitchell <mark@codesourcery.com>
* testsuite/Makefile.am (noinst_PROGRAMS): Remove.
Index: include/tr1/boost_shared_ptr.h
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/include/tr1/boost_shared_ptr.h,v
retrieving revision 1.1
diff -u -p -r1.1 boost_shared_ptr.h
--- include/tr1/boost_shared_ptr.h 24 Mar 2005 18:32:17 -0000 1.1
+++ include/tr1/boost_shared_ptr.h 1 Apr 2005 22:56:29 -0000
@@ -131,19 +131,22 @@ public:
void
add_ref_lock()
{
- if (_M_use_count <= 0) // TODO not yet MT safe XXX
+ __gnu_cxx::lock lock(_M_mutex);
+ if (__gnu_cxx::__exchange_and_add(&_M_use_count, 1) == 0)
{
+ _M_use_count = 0;
__throw_bad_weak_ptr();
}
- __gnu_cxx::__atomic_add(&_M_use_count, 1);
}
void
release() // nothrow
{
- if (__gnu_cxx::__exchange_and_add(&_M_use_count, -1) <= 1)
+ if (__gnu_cxx::__exchange_and_add(&_M_use_count, -1) == 1)
{
dispose();
+ __glibcxx_mutex_lock(_M_mutex);
+ __glibcxx_mutex_unlock(_M_mutex);
weak_release();
}
}
@@ -157,8 +160,10 @@ public:
void
weak_release() // nothrow
{
- if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) <= 1)
+ if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) == 1)
{
+ __glibcxx_mutex_lock(_M_mutex);
+ __glibcxx_mutex_unlock(_M_mutex);
destroy();
}
}
@@ -176,6 +181,7 @@ private:
_Atomic_word _M_use_count; // #shared
_Atomic_word _M_weak_count; // #weak + (#shared != 0)
+ __gnu_cxx::mutex_type _M_mutex;
};
template <typename _Ptr, typename _Deleter>
Index: include/tr1/memory
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/include/tr1/memory,v
retrieving revision 1.4
diff -u -p -r1.4 memory
--- include/tr1/memory 24 Mar 2005 18:32:17 -0000 1.4
+++ include/tr1/memory 1 Apr 2005 22:56:29 -0000
@@ -43,6 +43,7 @@
#include <bits/gthr.h>
#include <bits/atomicity.h>
#include <bits/functexcept.h>
+#include <bits/concurrence.h>
#include <debug/debug.h>
#include <tr1/boost_shared_ptr.h>
Index: testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared.cc,v
retrieving revision 1.1
diff -u -p -r1.1 not_shared.cc
--- testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared.cc 22 Feb 2005 00:10:19 -0000 1.1
+++ testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared.cc 1 Apr 2005 22:56:29 -0000
@@ -39,10 +39,12 @@ test01()
}
catch (const std::tr1::bad_weak_ptr&)
{
+ // Expected.
__throw_exception_again;
}
catch (...)
{
+ // Failed.
}
return 0;
Index: testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared2.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared2.cc,v
retrieving revision 1.1
diff -u -p -r1.1 not_shared2.cc
--- testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared2.cc 22 Feb 2005 00:10:19 -0000 1.1
+++ testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared2.cc 1 Apr 2005 22:56:29 -0000
@@ -41,8 +41,13 @@ test01()
}
catch (const std::tr1::bad_weak_ptr&)
{
+ // Expected.
__throw_exception_again;
}
+ catch (...)
+ {
+ // Failed.
+ }
return 0;
}
Index: testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared3.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared3.cc,v
retrieving revision 1.1
diff -u -p -r1.1 not_shared3.cc
--- testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared3.cc 22 Feb 2005 00:10:19 -0000 1.1
+++ testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/not_shared3.cc 1 Apr 2005 22:56:29 -0000
@@ -42,8 +42,13 @@ test01()
}
catch (const std::tr1::bad_weak_ptr&)
{
+ // Expected.
__throw_exception_again;
}
+ catch (...)
+ {
+ // Failed.
+ }
return 0;
}
Index: testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_neg.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_neg.cc,v
retrieving revision 1.2
diff -u -p -r1.2 auto_ptr_neg.cc
--- testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_neg.cc 22 Feb 2005 12:50:55 -0000 1.2
+++ testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_neg.cc 1 Apr 2005 22:56:29 -0000
@@ -47,6 +47,4 @@ main()
test01();
return 0;
}
-// { dg-error "In constructor" "" { target *-*-* } 0 }
-// { dg-error "cannot convert" "" { target *-*-* } 0 }
-// { dg-error "instantiated from" "" { target *-*-* } 0 }
+// { dg-excess-errors "In constructor" }
Index: testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_rvalue_neg.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_rvalue_neg.cc,v
retrieving revision 1.2
diff -u -p -r1.2 auto_ptr_rvalue_neg.cc
--- testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_rvalue_neg.cc 22 Feb 2005 12:50:55 -0000 1.2
+++ testsuite/tr1/2_general_utilities/memory/shared_ptr/assign/auto_ptr_rvalue_neg.cc 1 Apr 2005 22:56:29 -0000
@@ -46,5 +46,4 @@ main()
test01();
return 0;
}
-// { dg-error "auto_ptr" "" { target *-*-* } 0 }
-// { dg-error "shared_ptr" "" { target *-*-* } 0 }
+// { dg-excess-errors "candidates are" }
Index: testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/auto_ptr_neg.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/auto_ptr_neg.cc,v
retrieving revision 1.4
diff -u -p -r1.4 auto_ptr_neg.cc
--- testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/auto_ptr_neg.cc 24 Mar 2005 18:32:18 -0000 1.4
+++ testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/auto_ptr_neg.cc 1 Apr 2005 22:56:29 -0000
@@ -45,6 +45,4 @@ main()
test01();
return 0;
}
-// { dg-error "shared_ptr" "candidates are" { target *-*-* } 478 }
-
-// { dg-error "shared_ptr" "" { target *-*-* } 468 }
+// { dg-excess-errors "candidates are" }
Index: testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/weak_ptr_expired.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/weak_ptr_expired.cc,v
retrieving revision 1.1
diff -u -p -r1.1 weak_ptr_expired.cc
--- testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/weak_ptr_expired.cc 22 Feb 2005 00:10:20 -0000 1.1
+++ testsuite/tr1/2_general_utilities/memory/shared_ptr/cons/weak_ptr_expired.cc 1 Apr 2005 22:56:29 -0000
@@ -1,3 +1,4 @@
+// { dg-do run { xfail *-*-* } }
// Copyright (C) 2005 Free Software Foundation
//
// This file is part of the GNU ISO C++ Library. This library is free
@@ -34,6 +35,7 @@ test01()
std::tr1::shared_ptr<A> a1(new A);
std::tr1::weak_ptr<A> wa(a1);
a1.reset();
+ VERIFY( wa.expired() );
try
{
std::tr1::shared_ptr<A> a2(wa);
@@ -41,13 +43,12 @@ test01()
catch (const std::tr1::bad_weak_ptr&)
{
// Expected.
+ __throw_exception_again;
}
catch (...)
{
// Failed.
- __throw_exception_again;
}
- VERIFY( wa.expired() );
return 0;
}
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