Libc++ provides support for <thread> in C++03 as an extension. Furthermore,
it does not support any compiler that doesn't have rvalue references. It
is hence possible to provide the move constructor and move assignment
operator in C++03.
[cpp.predefined]p2:
__STDCPP_THREADS__
Defined, and has the value integer literal 1, if and only if a program
can have more than one thread of execution .
Also define it only if it's not defined already, since it's supposed
to be defined by the compiler.
Also move it from thread to __config (which requires setting it only
if _LIBCPP_HAS_NO_THREADS is not defined).
Part of PR33230. The intent is to eventually make the compiler define
this instead.
llvm-svn: 367316
to reflect the new license. These used slightly different spellings that
defeated my regular expressions.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351648
Summary:
When building with -fvisibility=hidden, some symbols do not get exported from
libc++.dylib. This means that some entities are not explicitly given default
visibility in the source code, and that we rely on the fact -fvisibility=default
is the default. This commit explicitly gives default visibility to those
symbols to avoid being dependent on the command line flags used.
The commit also remove symbols from the dylib -- those symbols do not
actually need to be exported from the dylib and this should not be an
ABI break.
Finally, in the future, we may want to mark the whole std:: namespace as
having hidden visibility (to switch from opt-out to opt-in), in which
case the changes done in this commit will be required.
Reviewers: EricWF
Subscribers: mgorny, christof, dexonsmith, libcxx-commits
Differential Revision: https://reviews.llvm.org/D52662
llvm-svn: 345260
Summary:
This patch improves how libc++ handles min/max macros within the headers. Previously libc++ would undef them and emit a warning.
This patch changes libc++ to use `#pragma push_macro` to save the macro before undefining it, and `#pragma pop_macro` to restore the macros and the end of the header.
Reviewers: mclow.lists, bcraig, compnerd, EricWF
Reviewed By: EricWF
Subscribers: cfe-commits, krytarowski
Differential Revision: https://reviews.llvm.org/D33080
llvm-svn: 304357
Summary:
Most classes annotated with _LIBCPP_TYPE_VIS need to have at least some
of their members exported, otherwise we have a lot of link errors when
linking against a libc++ built with hidden visibility. This also makes
_LIBCPP_TYPE_VIS be consistent across platforms, since on Windows it
already exports members.
With this change made, any template methods of a class marked
_LIBCPP_TYPE_VIS will also get default visibility when instantiatied,
which is not desirable for clients of libc++ headers who wish to control
their visibility; this is the same issue as PR30642. Annotate all
problematic methods with an explicit visibility specifier to avoid this.
The problematic methods were found by running bad-visibility-finder [1]
against the libc++ headers after making the _LIBCPP_TYPE_VIS change. The
small methods were marked for inlining; the larger ones hidden.
[1] https://github.com/smeenai/bad-visibility-finder
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D25208
llvm-svn: 296732
We have already refactored the underlying platform thread type into
__libcpp_thread_t, but there are few places in the source where we
still assume it is an integral type.
This patch refactores those points back into the threading API.
Differential revision: https://reviews.llvm.org/D28608
Reviewers: EricWF
llvm-svn: 292107
Add an implementation for the Win32 threading model as a backing API for
the internal c++ threading interfaces. This uses the Fls* family for
the TLS (which has the support for adding termination callbacks),
CRITICAL_SECTIONs for the recursive mutex, and Slim Reader/Writer locks
(SRW locks) for non-recursive mutexes. These APIs should all be
available on Vista or newer.
llvm-svn: 291333
The name _LIBCPP_TYPE_VIS_ONLY is no longer accurate because both
_LIBCPP_TYPE_VIS and _LIBCPP_TYPE_VIS_ONLY expand to
__attribute__((__type_visibility__)) with Clang. The only remaining difference
is that _LIBCPP_TYPE_VIS_ONLY can be applied to templates whereas
_LIBCPP_TYPE_VIS cannot (due to dllimport/dllexport not being allowed on
templates).
This patch renames _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS.
llvm-svn: 291035
This patch further decouples libc++ from pthread, allowing libc++ to be built
against other threading systems. There are two main use cases:
- Building libc++ against a thread library other than pthreads.
- Building libc++ with an "external" thread API, allowing a separate library to
provide the implementation of that API.
The two use cases are quite similar, the second one being sligtly more
de-coupled than the first. The cmake option LIBCXX_HAS_EXTERNAL_THREAD_API
enables both kinds of builds. One needs to place an <__external_threading>
header file containing an implementation of the "libc++ thread API" declared
in the <__threading_support> header.
For the second use case, the implementation of the libc++ thread API can
delegate to a custom "external" thread API where the implementation of this
external API is provided in a seperate library. This mechanism allows toolchain
vendors to distribute a build of libc++ with a custom thread-porting-layer API
(which is the "external" API above), platform vendors (recipients of the
toolchain/libc++) are then required to provide their implementation of this API
to be linked with (end-user) C++ programs.
Note that the second use case still requires establishing the basic types that
get passed between the external thread library and the libc++ library
(e.g. __libcpp_mutex_t). These cannot be opaque pointer types (libc++ sources
won't compile otherwise). It should also be noted that the second use case can
have a slight performance penalty; as all the thread constructs need to cross a
library boundary through an additional function call.
When the header <__external_threading> is omitted, libc++ is built with the
"libc++ thread API" (declared in <__threading_support>) as the "external" thread
API (basic types are pthread based). An implementation (pthread based) of this
API is provided in test/support/external_threads.cpp, which is built into a
separate DSO and linked in when running the libc++ test suite. A test run
therefore demonstrates the second use case (less the intermediate custom API).
Differential revision: https://reviews.llvm.org/D21968
Reviewers: bcraig, compnerd, EricWF, mclow.lists
llvm-svn: 281179
Summary:
This patch allows threads not created using `std::thread` to use `std::notify_all_at_thread_exit` by ensuring the TL state has been initialized within `std::notify_all_at_thread_exit`.
Additionally this patch "fixes" a potential oddity in `__thread_local_pointer::reset(pointer)`, which would previously delete the old thread local data. However there should *never* be old thread local data because pthread *should* null it out on thread exit. Unfortunately it's possible that pthread failed to do this according to the spec:
>
> Upon key creation, the value NULL shall be associated with the new key in all active threads. Upon thread creation, the value NULL shall be associated with all defined keys in the new thread.
>
> An optional destructor function may be associated with each key value. At thread exit, if a key value has a non-NULL destructor pointer, and the thread has a non-NULL value associated with that key, the value of the key is set to NULL, and then the function pointed to is called with the previously associated value as its sole argument. The order of destructor calls is unspecified if more than one destructor exists for a thread when it exits.
>
> If, after all the destructors have been called for all non-NULL values with associated destructors, there are still some non-NULL values with associated destructors, then the process is repeated. If, after at least {PTHREAD_DESTRUCTOR_ITERATIONS} iterations of destructor calls for outstanding non-NULL values, there are still some non-NULL values with associated destructors, implementations may stop calling destructors, or they may continue calling destructors until no non-NULL values with associated destructors exist, even though this might result in an infinite loop.
However if pthread fails to delete the value it is probably incorrect for us to do it. Destroying the value performs all of the "at thread exit" actions registered with it but we are way past "at thread exit".
Reviewers: mclow.lists, bcraig, EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D24159
llvm-svn: 280588
This patch extracts out all the pthread dependencies of libcxx into the
new header __threading_support. The motivation is to make it easy to
re-target libcxx into platforms that do not support pthread.
Original patch from Fulvio Esposito (fulvio.esposito@outlook.com) - D11781
Applied with tweaks - D19412
Change-Id: I301111f0075de93dd8129416e06babc195aa936b
llvm-svn: 268734
Summary:
Hi,
When creating a new thread libc++ performs at least 2 allocations. The first allocates a tuple of args and the functor that will be passed to the new thread. The second allocation is for the thread local storage needed internally by libc++. Currently the second allocation happens in the child thread, meaning that if it throws the program will terminate with an uncaught bad alloc.
The solution to this is to allocate ALL memory in the parent thread and then pass it to the child.
See https://llvm.org/bugs/show_bug.cgi?id=15638
Reviewers: mclow.lists, danalbert, jroelofs, EricWF
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D13748
llvm-svn: 266851
This change moves visibility attributes from out-of-class method
definitions to in-class declaration. This is needed for a switch to
attribute((internal_linkage)) (see http://reviews.llvm.org/D13925)
which can only appear on the first declaration.
This change does not touch istream/ostream/streambuf. They are
handled separately in http://reviews.llvm.org/D14409.
llvm-svn: 252385
Summary:
See https://llvm.org/bugs/show_bug.cgi?id=22606 for more discussion.
Most of the changes in this patch are file reorganization to help ensure assumptions about how __thread_specific_pointer is used hold. The assumptions are:
* `__thread_specific_ptr<Tp>` is only created with a `__thread_struct` pointer.
* `__thread_specific_ptr<Tp>` can only be constructed inside the `__thread_local_data()` function.
I'll remove the comments before committing. They are there for clarity during review.
Reviewers: earthdok, mclow.lists
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D8802
llvm-svn: 245334
It might be implicitly included by <pthread.h> (and that's why it worked
so far), but it's not guaranteed (for example, this is not the case with
newlib).
llvm-svn: 223661
If you're crazy enough to want this sort of thing, then add
-D_LIBCPP_HAS_NO_THREADS to your CXXFLAGS and
--param=additiona_features=libcpp-has-no-threads to your lit commnad line.
http://reviews.llvm.org/D3969
llvm-svn: 217271
functions to protect against duration and time_point overflow. Since
we're about to wait anyway, we can afford to spend a few more cycles on
this checking. I purposefully did not treat the timed try_locks with
overflow checking. This fixes
http://llvm.org/bugs/show_bug.cgi?id=13721 . I'm unsure if the standard
needs clarification in this area, or if this is simply QOI. The
<chrono> facilities were never intended to overflow check, but just to
not overflow if durations stayed within +/- 292 years.
llvm-svn: 162925
Joel E. Denny