Implement and map nqp::attrinited, uncomment more of NQPHLL. #15
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Hello @jnthn, I just pushed a new commit which implements is_attribute_initialized in P6opaque. |
diakopter
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Implement and map nqp::attrinited, uncomment more of NQPHLL.
FROGGS
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Issue #15. The core issue is that AO_stack_pop_explicit_aux_acquire really needs to ensure that the store to the blacklist via AO_compare_and_swap_acquire becomes visible before the load to check the list head. This effectively needs store-load ordering. Currently the only ordering here is imposed by the _acquire on the compare_and_swap. On PowerPC that turns into an lwsync, which is too weak to enforce store to load ordering. This patch should fix the issue. But this is suboptimal on x86, and we may want to make the fence conditional on "not x86", where the CAS already includes sufficient ordering. (With C++11 atomics, this would also be tricky and probably involve making a bunch of accesses seq_cst.) * src/atomic_ops_stack.c [AO_USE_ALMOST_LOCK_FREE] (AO_stack_pop_explicit_aux_acquire): Call AO_compare_and_swap instead of AO_compare_and_swap_acquire; call AO_nop_full just before (first != AO_load(list)). ivmai/libatomic_ops@85dd735 Author: Hans Boehm <boehm@acm.org> Date: Mon Aug 15 11:32:33 2016 +0300
FROGGS
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Nov 16, 2016
Issue #15. The core issue is that AO_stack_pop_explicit_aux_acquire really needs to ensure that the store to the blacklist via AO_compare_and_swap_acquire becomes visible before the load to check the list head. This effectively needs store-load ordering. Currently the only ordering here is imposed by the _acquire on the compare_and_swap. On PowerPC that turns into an lwsync, which is too weak to enforce store to load ordering. This patch should fix the issue. But this is suboptimal on x86, and we may want to make the fence conditional on "not x86", where the CAS already includes sufficient ordering. (With C++11 atomics, this would also be tricky and probably involve making a bunch of accesses seq_cst.) * src/atomic_ops_stack.c [AO_USE_ALMOST_LOCK_FREE] (AO_stack_pop_explicit_aux_acquire): Call AO_compare_and_swap instead of AO_compare_and_swap_acquire; call AO_nop_full just before (first != AO_load(list)). ivmai/libatomic_ops@85dd735 Author: Hans Boehm <boehm@acm.org> Date: Mon Aug 15 11:32:33 2016 +0300
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