compnerd added inline comments.
================
Comment at: include/__threading_support:300-305
+int __libcpp_recursive_mutex_init(__libcpp_mutex_t *__m)
+{
+ InitializeSRWLock(__m);
+ return 0;
+}
+
----------------
majnemer wrote:
> I don't think you can use slim rw locks for recursive locks. I think we will
> need to use `CRITICAL_SECTION` for those. std::recursive_mutex can't be used
> with std::condition_variable AFAIK so all you need (I think) is recursive
> versions of `__libcpp_mutex_...`
>
> Recursive locks should be used far less frequently which makes it valuable,
> IMO, to use slim rw locks for the non-recursive mutex implementation.
You are absolutely right. That was something that I looked at originally and
went with the CS. However, the overhead of a tagged struct is 5 or 9 bytes
(sizeof(void *) + 1) bytes (ignoring padding for MS ABI). Going with that
should give the benefits of always being able to properly initialize the CS
instead of the kludge.
================
Comment at: include/__threading_support:355
+ // TODO(compnerd) handle spurious timeout
+ if (!SleepConditionVariableSRW(__cv, __m,
+ duration_cast<milliseconds>(timeout).count(),
----------------
majnemer wrote:
> I don't think it should be `__libcpp_condvar_timedwait'`s problem.
> `__libcpp_condvar_timedwait` wraps `pthread_cond_timedwait` on POSIX
> platforms and the caller of `__libcpp_condvar_wait` properly handles spurious
> wakeups. The caller of `__libcpp_condvar_timedwait` probably should be
> audited.
SG; seems that there is a single user in condition_variable.cpp
Repository:
rL LLVM
https://reviews.llvm.org/D28220
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