Commit Graph

17 Commits

Author SHA1 Message Date
Louis Dionne 87dd51983c [libc++] Remove support for CloudABI, which has been abandoned
Based on https://github.com/NuxiNL/cloudlibc, it appears that the CloudABI
project has been abandoned. This patch removes a bunch of CloudABI specific
logic that had been added to support that platform.

Note that some knobs like LIBCXX_ENABLE_STDIN and LIBCXX_ENABLE_STDOUT
coud be useful in their own right, however those are currently broken.
If we want to re-add such knobs in the future, we can do it like we've
done it for localization & friends so that we can officially support
that configuration.

Differential Revision: https://reviews.llvm.org/D108637
2021-08-24 14:11:32 -04:00
Louis Dionne ebc01bbc7a [libc++] Skip logic for detecting C11 features when using_if_exists is supported
In the future, we'll want to rely exclusively on using_if_exists for this
job, but for now, only rely on it when the compiler supports that attribute.
That removes the possibility for getting the logic wrong.

Differential Revision: https://reviews.llvm.org/D108297
2021-08-18 11:53:34 -04:00
Louis Dionne a9c9183ca4 [libc++] Use the using_if_exists attribute when provided
As discussed on cfe-dev [1], use the using_if_exists Clang attribute when
the compiler supports it. This makes it easier to port libc++ on top of
new platforms that don't fully support the C Standard library.

Previously, libc++ would fail to build when trying to import a missing
declaration in a <cXXXX> header. With the attribute, the declaration will
simply not be imported into namespace std, and hence it won't be available
for libc++ to use. In many cases, the declarations were *not* actually
required for libc++ to work (they were only surfaced for users to use
them as std::XXXX), so not importing them into namespace std is acceptable.

The same thing could be achieved by conscious usage of `#ifdef` along
with platform detection, however that quickly creates a maintenance
problem as libc++ is ported to new platforms. Furthermore, this problem
is exacerbated when mixed with vendor internal-only platforms, which can
lead to difficulties maintaining a downstream fork of the library.

For the time being, we only use the using_if_exists attribute when it
is supported. At some point in the future, we will start removing #ifdef
paths that are unnecessary when the attribute is supported, and folks
who need those #ifdef paths will be required to use a compiler that
supports the attribute.

[1]: http://lists.llvm.org/pipermail/cfe-dev/2020-June/066038.html

Differential Revision: https://reviews.llvm.org/D90257
2021-06-04 09:55:21 -04:00
Louis Dionne 4cd6ca102a [libc++] NFC: Normalize `#endif //` comment indentation 2021-04-20 12:03:32 -04:00
Louis Dionne 5571467879 [libc++] Avoid including <sys/cdefs.h> on non-Apple platforms in <ctime> 2020-09-02 18:11:26 -04:00
Louis Dionne 5201b962e8 [libc++] Re-apply the workaround for timespec_get not always being available in Apple SDKs
This commit re-applies 99f3b231cb, which was reverted in 8142425727
because it broke the modules build. The modules failure was a circular
dependency between the Darwin module and __config. Specifically, the
issue was that if <__config> includes a system header, the std_config
module depends on the Darwin module. However, the Darwin module already
depends on the std_config header because some of its headers include
libc++ headers like <ctype.h> (they mean to include the C <ctype.h>,
but libc++ headers are first in the header search path).

This is fixed by moving the workaround to <ctime> only.

https://llvm.org/PR47208
rdar://68157284
2020-09-02 12:20:32 -04:00
Dan Albert 19fd9039ca Fix _LIBCPP_HAS_ definitions for Android.
Summary:
Android added quick_exit()/at_quick_exit() in API level 21,
aligned_alloc() in API level 28, and timespec_get() in API level 29,
but has the other C11 features at all API levels (since they're basically
just coming from clang directly).

_LIBCPP_HAS_QUICK_EXIT and _LIBCPP_HAS_TIMESPEC_GET already existed,
so we can reuse them. (And use _LIBCPP_HAS_TIMESPEC_GET in a few more
places where _LIBCPP_HAS_C11_FEATURES has been used as a proxy. This
isn't correct for Android.)

_LIBCPP_HAS_ALIGNED_ALLOC is added, to cover aligned_alloc() (obviously).

Add a missing std:: before aligned_alloc in a cstdlib test, and remove a
couple of !defined(_WIN32)s now that we're explicitly testing
TEST_HAS_ALIGNED_ALLOC rather than TEST_HAS_C11_FEATURES.

Reviewers: danalbert, EricWF, mclow.lists

Reviewed By: danalbert

Subscribers: srhines, christof, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D69929
2019-11-18 12:19:58 -08:00
Louis Dionne 6b77ebdc91 [NFC] Strip trailing whitespace from libc++ 2019-10-23 11:19:19 -07:00
Chandler Carruth 57b08b0944 Update more file headers across all of the LLVM projects in the monorepo
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
2019-01-19 10:56:40 +00:00
Marshall Clow 171c77b7da Selectively import timespec_get into namespace std, since some C libraries don't have it. Reviewed as https://reviews.llvm.org/D50799
llvm-svn: 339816
2018-08-15 21:19:08 +00:00
Marshall Clow deb471fa15 import timespec and timespec_get into namespace std if we're under c++17 or later AND the underlying C library has them. Fixes PR#38220, but doesn't implement all of P0063 yet.
llvm-svn: 338419
2018-07-31 19:25:00 +00:00
Ed Schouten e0cf3b9a3c Make support for thread-unsafe C functions optional.
One of the aspects of CloudABI is that it aims to help you write code
that is thread-safe out of the box. This is very important if you want
to write libraries that are easy to reuse. For CloudABI we decided to
not provide the thread-unsafe functions. So far this is working out
pretty well, as thread-unsafety issues are detected really early on.

The following patch adds a knob to libc++,
_LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS, that can be set to disable
thread-unsafe functions that can easily be avoided in practice. The
following functions are not thread-safe:

- <clocale>: locale handles should be preferred over setlocale().
- <cstdlib>: mbrlen(), mbrtowc() and wcrtomb() should be preferred over
  their non-restartable counterparts.
- <ctime>: asctime(), ctime(), gmtime() and localtime() are not
  thread-safe. The first two are also deprecated by POSIX.

Differential Revision:	http://reviews.llvm.org/D8703
Reviewed by:	marshall

llvm-svn: 240527
2015-06-24 08:44:38 +00:00
Howard Hinnant 073458b1ab Windows support by Ruben Van Boxem.
llvm-svn: 142235
2011-10-17 20:05:10 +00:00
Howard Hinnant 412dbebe1b license change
llvm-svn: 119395
2010-11-16 22:09:02 +00:00
Howard Hinnant b3371f6f49 Fixing whitespace problems
llvm-svn: 111750
2010-08-22 00:02:43 +00:00
Howard Hinnant 5b08a8a432 Wiped out some non-ascii characters that snuck into the copyright.
llvm-svn: 103516
2010-05-11 21:36:01 +00:00
Howard Hinnant 3e519524c1 libcxx initial import
llvm-svn: 103490
2010-05-11 19:42:16 +00:00