espositofulvio added a comment.
In http://reviews.llvm.org/D11781#227446, @EricWF wrote:
> This patch has a long way to go but it has also come a long way. Here are a
> couple of problems I see with it.
>
> 2. This patch adds a lot of headers. libc++ has historically tried to keep
> the number of headers to a minimum for the reason that filesystem operations
> are expensive and its cheaper to include a few big headers as opposed to many
> small ones.
I know but it was a request from reviewers so that platform specific decision
were localized. I can obviously merge all of the support/mutex.h,
support/thread.h and support/condition_variable.h in a single support/thread.h
if that's the case.
================
Comment at: include/type_traits:222
@@ -221,3 +221,3 @@
-template <class _Tp>
-struct __identity { typedef _Tp type; };
+template <class T>
+struct __identity { typedef T type; };
----------------
EricWF wrote:
> This change seems to have snuck in.
Yes, and actually I'm not sure how it did as it's something I haven't touched.
Unfortunately I don't have time before later next week to address all the
issues.
================
Comment at: src/algorithm.cpp:51
@@ -50,3 +50,3 @@
#ifndef _LIBCPP_HAS_NO_THREADS
-static pthread_mutex_t __rs_mut = PTHREAD_MUTEX_INITIALIZER;
+static mutex __rs_mut;
#endif
----------------
EricWF wrote:
> I think this prevents __rs_mut from being initialized during constant
> initialization.
> (http://en.cppreference.com/w/cpp/language/constant_initialization)
I think this falls in the second case:
Static or thread-local object of class type that is initialized by a
constructor call, if the constructor is constexpr and all constructor arguments
(including implicit conversions) are constant expressions, and if the
initializers in the constructor's initializer list and the brace-or-equal
initializers of the class memebers only contain constant expressions.
but I was actually relying on the fact that we have constexpr, which now I
understand could not be the case.
================
Comment at: src/memory.cpp:130
@@ -129,3 +129,1 @@
static const std::size_t __sp_mut_count = 16;
-static pthread_mutex_t mut_back_imp[__sp_mut_count] =
-{
----------------
EricWF wrote:
> I have no idea what is going on here. Do you understand what this code was
> trying to do?
My understanding is that this is trying to init the array during constant
initialization and later relying on the internal layout of std::mutex to be
equal to a pthread_mutex_t to cast it and use it as a std::mutex.
from cppreference:
Static or thread-local object (not necessarily of class type), that is not
initialized by a constructor call, if the object is value-initialized or if
every expression in its initializer is a constant expression.
Again, I think my change should be ok as long as constexpr is available, but I
could be wrong.
Repository:
rL LLVM
http://reviews.llvm.org/D11781
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
