<condition_variable>: Avoid squirrelly forward declaration of _Cnd_internal_imp_t
#4545
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This will allow us to move the definition of `_Cnd_internal_imp_t` into `__msvc_threads_core.hpp`. This is a safe transformation because only 3 files include `primitives.hpp` and they already drag in `__msvc_threads_core.hpp` (`sharedmutex.cpp` directly; `cond.cpp` and `mutex.cpp` via `xthreads.h`).
… `cv` to `_Cv_storage`. This will allow us to move the definition into `stl/inc/__msvc_threads_core.hpp`. The new name is consistent with how `_Mtx_internal_imp_t` names its `_Aligned_storage_t` data member `_Cs_storage`.
…tails::_Get_cond_var` Change the member function `_Cnd_internal_imp_t::_get_cv` into the non-member function `Concurrency::details::_Get_cond_var`, renamed to be more descriptive. Drop the unnecessary comment `// get pointer to implementation`. Now we don't need to qualify `stl_condition_variable_win7`, defined immediately above. We need to take a parameter `::_Cnd_internal_imp_t* _Cond`, qualified for clarity. We need `inline` for the non-member function.
… `__msvc_threads_core.hpp`. This is still within `extern "C"`. Change `std::` => `_STD`. We no longer need the wacky `/clr` forward declaration workaround.
We can do this because its only data member is exactly `_Aligned_storage_t<_Cnd_internal_imp_size, _Cnd_internal_imp_alignment>`, so the representation is unchanged. Then we can simplify the `_Mycnd()` member function. This follows the same pattern as `_Mutex_base`'s `_Mtx_internal_imp_t _Mtx_storage` and `_Mymtx()`.
…Cnd_internal_imp_t`. This changes `_INLINE_VAR` to `static`. The comment `// Size and alignment for _Cnd_internal_imp_t` is now unnecessary and can be dropped.
… their only uses.
This expresses "16 or 8 bytes" as `2 * sizeof(void*)`.
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I'm speculatively mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed. |
CaseyCarter
approved these changes
Apr 9, 2024
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Followup to #4457 (comment). I performed this as a series of well-structured commits.
Commits
primitives.hpp: Include__msvc_threads_core.hpp.This will allow us to move the definition of
_Cnd_internal_imp_tinto__msvc_threads_core.hpp.This is a safe transformation because only 3 files include
primitives.hppand they already drag in__msvc_threads_core.hpp(sharedmutex.cppdirectly;cond.cppandmutex.cppviaxthreads.h).In
_Cnd_internal_imp_t, rename its_Aligned_storage_tdata membercvto_Cv_storage.This will allow us to move the definition into
stl/inc/__msvc_threads_core.hpp.The new name is consistent with how
_Mtx_internal_imp_tnames its_Aligned_storage_tdata member_Cs_storage.Change definition:
_Cnd_internal_imp_t::_get_cv=>Concurrency::details::_Get_cond_varChange the member function
_Cnd_internal_imp_t::_get_cvinto the non-member functionConcurrency::details::_Get_cond_var, renamed to be more descriptive.Drop the unnecessary comment
// get pointer to implementation.Now we don't need to qualify
stl_condition_variable_win7, defined immediately above.We need to take a parameter
::_Cnd_internal_imp_t* _Cond, qualified for clarity.We need
inlinefor the non-member function.Replace calls:
cond->_get_cv()=>Concurrency::details::_Get_cond_var(cond)Move the definition of
_Cnd_internal_imp_tfromprimitives.hppto__msvc_threads_core.hpp.This is still within
extern "C".Change
std::=>_STD.We no longer need the wacky
/clrforward declaration workaround.Directly store
_Cnd_internal_imp_t _Cnd_storage.We can do this because its only data member is exactly
_Aligned_storage_t<_Cnd_internal_imp_size, _Cnd_internal_imp_alignment>, so the representation is unchanged.Then we can simplify the
_Mycnd()member function.This follows the same pattern as
_Mutex_base's_Mtx_internal_imp_t _Mtx_storageand_Mymtx().Move
_Cnd_internal_imp_size/_Cnd_internal_imp_alignmentwithin_Cnd_internal_imp_t.This changes
_INLINE_VARtostatic.The comment
// Size and alignment for _Cnd_internal_imp_tis now unnecessary and can be dropped.Fuse
_Critical_section_alignand_Cnd_internal_imp_alignmentinto their only uses.Follow
_Cnd_internal_imp_t's simpler pattern in_Mtx_internal_imp_t.This expresses "16 or 8 bytes" as
2 * sizeof(void*).Note
After this, I believe that we should apply a similar bugfix as #4294, checking
UNDOCKED_WINDOWS_UCRTwhen determining_Cnd_internal_imp_size, but I'm not doing that here (mixing functional changes with cleanups is bad).