From: Andi Kleen <a...@linux.intel.com>
When a non constant memory model is passed to __atomic_*
gcc falls back to seq_cst. This drops any HLE acquire or release bits.
This can happen when <atomic> is used with -O0
as the member functions are not always inlined then and the memory
argument passed in ends up being non-constant.
With inline __attribute__((always_inline)) these functions
get inlined even with -O0.
I hardcoded the attribute in the header for now, assuming
that all compilers that support libstdc++ have attribute
always_inline too. If not it would need to be moved
as a macro to c++config.h with appropiate ifdefs.
We still need a warning for this case too, that will be submitted
separately.
I would like to have this patch in the 4.8 series if possible, to make
sure HLE works well with <atomic>
Passed bootstrap and test on x86_64-linux.
libstdc++v3/:
2013-03-15 Andi Kleen <a...@linux.intel.com>
PR target/55947
* libstdc++-v3/include/bits/atomic_base.h
(__always_inline): Add new macro.
(atomic_thread_fence, atomic_signal_fence, test_and_set,
clear, store, load, exchange, compare_exchange_weak)
compare_exchange_strong, fetch_add, fetch_sub, fetch_and,
fetch_or, fetch_xor): Mark __always_inline.
---
libstdc++-v3/include/bits/atomic_base.h | 88 ++++++++++++++++---------------
1 file changed, 46 insertions(+), 42 deletions(-)
diff --git a/libstdc++-v3/include/bits/atomic_base.h
b/libstdc++-v3/include/bits/atomic_base.h
index 609fe8b..475ffa0 100644
--- a/libstdc++-v3/include/bits/atomic_base.h
+++ b/libstdc++-v3/include/bits/atomic_base.h
@@ -37,6 +37,10 @@
#include <stdint.h>
#include <bits/atomic_lockfree_defines.h>
+#ifndef __always_inline
+#define __always_inline inline __attribute__((always_inline))
+#endif
+
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -94,11 +98,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
| (__m & __memory_order_modifier_mask));
}
- inline void
+ __always_inline void
atomic_thread_fence(memory_order __m) noexcept
{ __atomic_thread_fence(__m); }
- inline void
+ __always_inline void
atomic_signal_fence(memory_order __m) noexcept
{ __atomic_signal_fence(__m); }
@@ -281,19 +285,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: __atomic_flag_base{ _S_init(__i) }
{ }
- bool
+ __always_inline bool
test_and_set(memory_order __m = memory_order_seq_cst) noexcept
{
return __atomic_test_and_set (&_M_i, __m);
}
- bool
+ __always_inline bool
test_and_set(memory_order __m = memory_order_seq_cst) volatile noexcept
{
return __atomic_test_and_set (&_M_i, __m);
}
- void
+ __always_inline void
clear(memory_order __m = memory_order_seq_cst) noexcept
{
memory_order __b = __m & __memory_order_mask;
@@ -304,7 +308,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__atomic_clear (&_M_i, __m);
}
- void
+ __always_inline void
clear(memory_order __m = memory_order_seq_cst) volatile noexcept
{
memory_order __b = __m & __memory_order_mask;
@@ -463,7 +467,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
is_lock_free() const volatile noexcept
{ return __atomic_is_lock_free(sizeof(_M_i), nullptr); }
- void
+ __always_inline void
store(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept
{
memory_order __b = __m & __memory_order_mask;
@@ -474,7 +478,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__atomic_store_n(&_M_i, __i, __m);
}
- void
+ __always_inline void
store(__int_type __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{
@@ -486,7 +490,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__atomic_store_n(&_M_i, __i, __m);
}
- __int_type
+ __always_inline __int_type
load(memory_order __m = memory_order_seq_cst) const noexcept
{
memory_order __b = __m & __memory_order_mask;
@@ -496,7 +500,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_load_n(&_M_i, __m);
}
- __int_type
+ __always_inline __int_type
load(memory_order __m = memory_order_seq_cst) const volatile noexcept
{
memory_order __b = __m & __memory_order_mask;
@@ -506,7 +510,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_load_n(&_M_i, __m);
}
- __int_type
+ __always_inline __int_type
exchange(__int_type __i,
memory_order __m = memory_order_seq_cst) noexcept
{
@@ -514,14 +518,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
- __int_type
+ __always_inline __int_type
exchange(__int_type __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{
return __atomic_exchange_n(&_M_i, __i, __m);
}
- bool
+ __always_inline bool
compare_exchange_weak(__int_type& __i1, __int_type __i2,
memory_order __m1, memory_order __m2) noexcept
{
@@ -534,7 +538,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, __m1, __m2);
}
- bool
+ __always_inline bool
compare_exchange_weak(__int_type& __i1, __int_type __i2,
memory_order __m1,
memory_order __m2) volatile noexcept
@@ -548,7 +552,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, __m1, __m2);
}
- bool
+ __always_inline bool
compare_exchange_weak(__int_type& __i1, __int_type __i2,
memory_order __m = memory_order_seq_cst) noexcept
{
@@ -556,7 +560,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__m));
}
- bool
+ __always_inline bool
compare_exchange_weak(__int_type& __i1, __int_type __i2,
memory_order __m = memory_order_seq_cst) volatile noexcept
{
@@ -564,7 +568,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__m));
}
- bool
+ __always_inline bool
compare_exchange_strong(__int_type& __i1, __int_type __i2,
memory_order __m1, memory_order __m2) noexcept
{
@@ -577,7 +581,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, __m1, __m2);
}
- bool
+ __always_inline bool
compare_exchange_strong(__int_type& __i1, __int_type __i2,
memory_order __m1,
memory_order __m2) volatile noexcept
@@ -592,7 +596,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, __m1, __m2);
}
- bool
+ __always_inline bool
compare_exchange_strong(__int_type& __i1, __int_type __i2,
memory_order __m = memory_order_seq_cst) noexcept
{
@@ -600,7 +604,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__m));
}
- bool
+ __always_inline bool
compare_exchange_strong(__int_type& __i1, __int_type __i2,
memory_order __m = memory_order_seq_cst) volatile noexcept
{
@@ -608,52 +612,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__m));
}
- __int_type
+ __always_inline __int_type
fetch_add(__int_type __i,
memory_order __m = memory_order_seq_cst) noexcept
{ return __atomic_fetch_add(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_add(__int_type __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return __atomic_fetch_add(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_sub(__int_type __i,
memory_order __m = memory_order_seq_cst) noexcept
{ return __atomic_fetch_sub(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_sub(__int_type __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return __atomic_fetch_sub(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_and(__int_type __i,
memory_order __m = memory_order_seq_cst) noexcept
{ return __atomic_fetch_and(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_and(__int_type __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return __atomic_fetch_and(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_or(__int_type __i,
memory_order __m = memory_order_seq_cst) noexcept
{ return __atomic_fetch_or(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_or(__int_type __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return __atomic_fetch_or(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_xor(__int_type __i,
memory_order __m = memory_order_seq_cst) noexcept
{ return __atomic_fetch_xor(&_M_i, __i, __m); }
- __int_type
+ __always_inline __int_type
fetch_xor(__int_type __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return __atomic_fetch_xor(&_M_i, __i, __m); }
@@ -770,7 +774,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
is_lock_free() const volatile noexcept
{ return __atomic_is_lock_free(_M_type_size(1), nullptr); }
- void
+ __always_inline void
store(__pointer_type __p,
memory_order __m = memory_order_seq_cst) noexcept
{
@@ -783,7 +787,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__atomic_store_n(&_M_p, __p, __m);
}
- void
+ __always_inline void
store(__pointer_type __p,
memory_order __m = memory_order_seq_cst) volatile noexcept
{
@@ -795,7 +799,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__atomic_store_n(&_M_p, __p, __m);
}
- __pointer_type
+ __always_inline __pointer_type
load(memory_order __m = memory_order_seq_cst) const noexcept
{
memory_order __b = __m & __memory_order_mask;
@@ -805,7 +809,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_load_n(&_M_p, __m);
}
- __pointer_type
+ __always_inline __pointer_type
load(memory_order __m = memory_order_seq_cst) const volatile noexcept
{
memory_order __b = __m & __memory_order_mask;
@@ -815,7 +819,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_load_n(&_M_p, __m);
}
- __pointer_type
+ __always_inline __pointer_type
exchange(__pointer_type __p,
memory_order __m = memory_order_seq_cst) noexcept
{
@@ -823,14 +827,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
- __pointer_type
+ __always_inline __pointer_type
exchange(__pointer_type __p,
memory_order __m = memory_order_seq_cst) volatile noexcept
{
return __atomic_exchange_n(&_M_p, __p, __m);
}
- bool
+ __always_inline bool
compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
memory_order __m1,
memory_order __m2) noexcept
@@ -844,7 +848,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, __m1, __m2);
}
- bool
+ __always_inline bool
compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
memory_order __m1,
memory_order __m2) volatile noexcept
@@ -859,22 +863,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, __m1, __m2);
}
- __pointer_type
+ __always_inline __pointer_type
fetch_add(ptrdiff_t __d,
memory_order __m = memory_order_seq_cst) noexcept
{ return __atomic_fetch_add(&_M_p, _M_type_size(__d), __m); }
- __pointer_type
+ __always_inline __pointer_type
fetch_add(ptrdiff_t __d,
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return __atomic_fetch_add(&_M_p, _M_type_size(__d), __m); }
- __pointer_type
+ __always_inline __pointer_type
fetch_sub(ptrdiff_t __d,
memory_order __m = memory_order_seq_cst) noexcept
{ return __atomic_fetch_sub(&_M_p, _M_type_size(__d), __m); }
- __pointer_type
+ __always_inline __pointer_type
fetch_sub(ptrdiff_t __d,
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return __atomic_fetch_sub(&_M_p, _M_type_size(__d), __m); }
--
1.7.10.4
