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Re: [PATCH] fix generic std::atomic<T>::compare_exchange_{weak,strong}
- From: Nathan Froyd <froydnj at mozilla dot com>
- To: Paolo Carlini <paolo dot carlini at oracle dot com>
- Cc: libstdc++ at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Fri, 26 Jul 2013 16:07:11 -0700 (PDT)
- Subject: Re: [PATCH] fix generic std::atomic<T>::compare_exchange_{weak,strong}
- References: <20130726173426 dot GA11900 at cerebro> <3c498ca8-12e6-48ec-9e2b-bb2abc6e3851 at email dot android dot com> <1044586962 dot 21254 dot 1374864154989 dot JavaMail dot zimbra at mozilla dot com> <51F2CF54 dot 2070700 at oracle dot com>
----- Original Message -----
> On 07/26/2013 08:42 PM, Nathan Froyd wrote:
> > Sure, I can do that. For maximum effectiveness, it'd be good to have it
> > check the specializations for atomic<>, too. Is there something in the
> > libstdc++ testsuite for iterating template instantiations over a list of
> > types, or do I have to roll the list myself?
> testsuite/29_atomics already uses testsuite_common_types.h
New patch, this time with tests. Let me know if test placement, etc. need
adjusting.
Tested on x86_64-unknown-linux-gnu. OK for commit to trunk and active branches?
-Nathan
* include/std/atomic (compare_exchange_weak, compare_exchange_strong):
Add call to __cmpexch_failure_order.
* testsuite/util/testsuite_common_types.h
(compare_exchange_order_lowering): New generator.
* testsuite/29_atomics/atomic/requirements/compare_exchange_lowering.cc:
New test.
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ac2cb45..3b79d91 100644
diff --git a/libstdc++-v3/include/std/atomic b/libstdc++-v3/include/std/atomic
index 813f574..2d66729 100644
--- a/libstdc++-v3/include/std/atomic
+++ b/libstdc++-v3/include/std/atomic
@@ -252,12 +252,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
bool
compare_exchange_weak(_Tp& __e, _Tp __i,
memory_order __m = memory_order_seq_cst) noexcept
- { return compare_exchange_weak(__e, __i, __m, __m); }
+ { return compare_exchange_weak(__e, __i, __m,
+ __cmpexch_failure_order(__m)); }
bool
compare_exchange_weak(_Tp& __e, _Tp __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
- { return compare_exchange_weak(__e, __i, __m, __m); }
+ { return compare_exchange_weak(__e, __i, __m,
+ __cmpexch_failure_order(__m)); }
bool
compare_exchange_strong(_Tp& __e, _Tp __i, memory_order __s,
@@ -276,12 +278,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
bool
compare_exchange_strong(_Tp& __e, _Tp __i,
memory_order __m = memory_order_seq_cst) noexcept
- { return compare_exchange_strong(__e, __i, __m, __m); }
+ { return compare_exchange_strong(__e, __i, __m,
+ __cmpexch_failure_order(__m)); }
bool
compare_exchange_strong(_Tp& __e, _Tp __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
- { return compare_exchange_strong(__e, __i, __m, __m); }
+ { return compare_exchange_strong(__e, __i, __m,
+ __cmpexch_failure_order(__m)); }
};
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/requirements/compare_exchange_lowering.cc b/libstdc++-v3/testsuite/29_atomics/atomic/requirements/compare_exchange_lowering.cc
new file mode 100644
index 0000000..75e7406
--- /dev/null
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/requirements/compare_exchange_lowering.cc
@@ -0,0 +1,65 @@
+// { dg-options "-std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2008-2013 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <atomic>
+#include <testsuite_common_types.h>
+
+#define TEST_ALL_ORDERS() \
+ do { \
+ ORDER_TEST(std::memory_order_relaxed); \
+ ORDER_TEST(std::memory_order_consume); \
+ ORDER_TEST(std::memory_order_acquire); \
+ ORDER_TEST(std::memory_order_release); \
+ ORDER_TEST(std::memory_order_acq_rel); \
+ ORDER_TEST(std::memory_order_seq_cst); \
+ } while(0)
+
+void test01()
+{
+#define ORDER_TEST(ORDER) \
+ do { \
+ __gnu_test::compare_exchange_order_lowering<ORDER> test; \
+ __gnu_cxx::typelist::apply_generator(test, \
+ __gnu_test::integral_types::type()); \
+ } while (0);
+ TEST_ALL_ORDERS();
+#undef ORDER_TEST
+
+ enum e { a, b, c };
+#define ORDER_TEST(ORDER) \
+ do { \
+ std::atomic<e> x(a); \
+ e expected = a; \
+ x.compare_exchange_strong(expected, b, ORDER); \
+ x.compare_exchange_weak(expected, c, ORDER); \
+ } while (0);
+ TEST_ALL_ORDERS();
+#undef ORDER_TEST
+
+#define ORDER_TEST(ORDER) \
+ do { \
+ std::atomic<void*> x(nullptr); \
+ void* expected = nullptr; \
+ x.compare_exchange_strong(expected, nullptr, ORDER); \
+ x.compare_exchange_weak(expected, nullptr, ORDER); \
+ } while (0);
+ TEST_ALL_ORDERS();
+#undef ORDER_TEST
+}
diff --git a/libstdc++-v3/testsuite/util/testsuite_common_types.h b/libstdc++-v3/testsuite/util/testsuite_common_types.h
index 54d6a75..e7f081b 100644
--- a/libstdc++-v3/testsuite/util/testsuite_common_types.h
+++ b/libstdc++-v3/testsuite/util/testsuite_common_types.h
@@ -872,5 +872,22 @@ namespace __gnu_test
= &_Concept::__constraint;
}
};
+
+#if __cplusplus >= 201103L
+ // Generator to test lowering requirements for compare-and-exchange.
+ template<std::memory_order order>
+ struct compare_exchange_order_lowering
+ {
+ template<typename _Tp>
+ void
+ operator()()
+ {
+ std::atomic<_Tp> x;
+ _Tp __expected = 0;
+ x.compare_exchange_strong(__expected, 1, order);
+ x.compare_exchange_weak(__expected, 1, order);
+ }
+ };
+#endif
} // namespace __gnu_test
#endif