This patch adds support for atomic operations on Solaris, on any platform.
It makes use of the atomic functions made available in Solaris' atomic.h
header.
__atomic_store_n() cannot take a memory model argument of
__ATOMIC_ACQUIRE, and __atomic_load_n() cannot take a memory model
argument of __ATOMIC_RELEASE, per the GCC documentation:
https://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/_005f_005fatomic-Builtins.html
On Clang this generates a -Watomic-memory-ordering warning.
Promote the fences in Acquire_Store() and Release_Load() to the stronger
__ATOMIC_SEQ_CST memory model, which ought to be safe.
Note that there are no actual uses of Acquire_Store() or Release_Load()
in protobuf, though.
This follows the TSAN atomicops implementation, which also uses SEQ_CST
fences for these functions.
(Fixes #25.)
We cannot use Clang's __has_extension macro unless we really are
compiling on Clang, which means we cannot use this expression:
#if (defined(__clang__) && __has_extension(c_atomic)))
// ...
#endif
On GCC, this generates the following errors:
In file included from ./google/protobuf/stubs/atomicops.h:59:0,
from google/protobuf/stubs/atomicops_internals_x86_gcc.cc:36:
./google/protobuf/stubs/platform_macros.h:67:41: error: missing binary operator before token "("
(defined(__clang__) && __has_extension(c_atomic)))
^
In file included from google/protobuf/stubs/atomicops_internals_x86_gcc.cc:36:0:
./google/protobuf/stubs/atomicops.h:196:40: error: missing binary operator before token "("
(defined(__clang__) && __has_extension(c_atomic))
^
Instead, we have to protect the __has_extension expression by only
executing it when __clang__ is defined:
#if defined(__clang__)
# if __has_extension(c_atomic)
// ...
# endif
#endif
In the current implementation, a message with the same amount of null or
equal-valued fields as a different message type will have the same
hashCode. This adds more variety by including the hashCode of the
class's name in the hashCode calculations.
Change-Id: I284e3e6d198ad8037815948d1f65686465ffd623
Signed-off-by: Jason Neufeld <jneufeld@google.com>
Feng Xiao
John Beard
Dwayne Litzenberger
William Orr
Antoni Buszta
Brian Duff
Dinis Rosário
Robert Edmonds
Jason Neufeld