clock_gettime is a POSIX API that may not be available on platforms like
baremetal; timespec_get is the C11 equivalent. This change adds support
for using timespec_get instead of clock_gettime to improve compatibility
with non-POSIX platforms. For now, this is only enabled with LLVM libc
which implemented timespec_get in #116102, but in the future this can be
expanded to other platforms.
Related to #84879.
The variables are all `constexpr`, which implies `inline`. Since they
aren't `constexpr` in C++03 they're also not `inline` there. Because of
that we define them out-of-line currently. Instead we can use the C++17
extension of `inline` variables, which results in the same weak
definitions of the variables but without having all the boilerplate.
Summary:
I am attempting to get the GPU to build and support libc++. One issue
I've encountered is that it will look for `timeval` unless this macro is
set. We can support `CLOCK_MONOTONIC` on the GPU fairly easily as we
have access to a fixed-frequency clock via `__builtin_readsteadycounter`
intrinsics with a known frequency. This also requires `CLOCK_REALTIME`
which we can't support, but provide anyway from the GPU `libc` to make
this happy. It will return an error so at least that will be obvious.
I may need a more consistent configuration for this in the future, maybe
I should put a common macro in a different common header that's just
`__GPU__`? I don't know where I would put such a thing however.
This avoids the following build time warning, when building with the
latest nightly Clang:
warning: cast from 'FARPROC' (aka 'int (*)() __attribute__((stdcall))')
to
'GetSystemTimeAsFileTimePtr' (aka 'void (*)(_FILETIME *)
__attribute__((stdcall))')
converts to incompatible function type [-Wcast-function-type-mismatch]
This warning seems to have appeared since Clang commit
999d4f840777bf8de26d45947192aa0728edc0fb, which restructured.
The GetProcAddress function returns a `FARPROC` type, which is `int
(WINAPI *)()`. Directly casting this to another function pointer type
triggers this warning, but casting to a `void*` inbetween avoids this
issue. (On Unix-like platforms, dlsym returns a `void*`, which doesn't
exhibit this casting problem.)
- No indirect syscalls on OpenBSD. Instead there is a `futex` function
which issues a direct syscall.
- Monotonic clock is available despite the full POSIX suite of timers
not being available in its entirety.
See https://lists.boost.org/boost-bugs/2015/07/41690.php and
c98b1f459a
for a description of an analogous problem and fix for Boost.
This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmarks, the test suite and remaining parts of the code. I'm
splitting this one into its own patch so the diff is a bit easier to
review.
This patch was generated with:
find libcxx/include libcxx/src -type f \
| grep -v 'module.modulemap.in' \
| grep -v 'CMakeLists.txt' \
| grep -v 'README.txt' \
| grep -v 'libcxx.imp' \
| grep -v '__config_site.in' \
| xargs clang-format -i
A Git merge driver is available in libcxx/utils/clang-format-merge-driver.sh
to help resolve merge and rebase issues across these formatting changes.
[1]: https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
GNU/Hurd does have clock_gettime, it just doesn't define _POSIX_TIMERS because its support for timers is not complete.
Reviewed By: #libc, Mordante
Differential Revision: https://reviews.llvm.org/D158584
This patch partly reverts the change that was made in 5f1ba3a502
regarding the clock selection on Apple platforms. It turns out that
gettimeofday() is marked as obsolete by POSIX and clock_gettime() is
recommended instead. Since both are equivalent for our purposes,
prefer using clock_gettime() even on Apple platforms.
Differential Revision: https://reviews.llvm.org/D155022
Note that _FilesystemClock will now be implemented by calling gettimeofday()
on Apple platforms instead of clock_gettime(). However, since both are
equivalent, this should not change the behavior on Apple platforms.
There should be no behavior change on other platforms.
In addition to being a consistency clean up, this fixes some issues seen
by folks as reported in https://reviews.llvm.org/D154390#4471924.
Differential Revision: https://reviews.llvm.org/D154457
This patch bumps the minimum macOS version for building the dylib
or back-deploying a statically-linked libc++ from macOS 10.11 to
macOS 10.13. AFAICT, Chrome was the last one to require macOS 10.11,
but since then they have bumped their minimal supported version to
macOS 10.13.
Differential Revision: https://reviews.llvm.org/D145012
Our best guess is that the two syntaxes should have exactly equivalent
effects, so, let's be consistent with what we do in libcxx/include/.
I've left `#include "include/x.h"` and `#include "../y.h"` alone
because I'm less sure that they're interchangeable, and they aren't
inconsistent with libcxx/include/ because libcxx/include/ never
does that kind of thing.
Also, use the `_LIBCPP_PUSH_MACROS/POP_MACROS` dance for `<__undef_macros>`,
even though it's technically unnecessary in a standalone .cpp file,
just so we have consistently one way to do it.
Differential Revision: https://reviews.llvm.org/D119561
Use the zx_clock_get_monotonic system call directly rather than
going through the POSIX clock_gettime function. The libc function
is a trivial wrapper around the system call, and is not a standard C
function. Avoiding it reduces the Fuchsia libc ABI surface that
libc++ depends on.
Reviewed By: phosek, ldionne, #libc
Differential Revision: https://reviews.llvm.org/D116606
We had previously been using a different workaround for pretending that
we were inside a system header, however it had some undesirable effects
on dependency parsing for build systems, as explained in [1].
This patch changes the workaround to use `#pragma GCC system_header`,
which shouldn't suffer from the same issue. Unfortunately, it is a lot
more verbose. The issue is that `#pragma GCC system_header` is ignored
when we are inside a source file, so we have to create a header just for
the sake of using it. IMO this seems like an artificial restriction
without much benefit, but investigating that is a different story.
For now, this should at least solve build system problems at the
cost of some readability.
[1]: https://reviews.llvm.org/D95972#3178968
Differential Revision: https://reviews.llvm.org/D115334
We've stopped doing it in libc++ for a while now because these names
would end up rotting as we move things around and copy/paste stuff.
This cleans up all the existing files so as to stop the spreading
as people copy-paste headers around.
This was missed in D95972 / 7c49052b170f76f19be64a5572d31ad8f5df4e61,
as this codepath isn't exercised by CI yet.
Differential Revision: https://reviews.llvm.org/D111292
We will try to use GetSystemTimePreciseAsFileTime if possible.
Reference: 59195b2d7f/.
Reviewed By: compnerd, #libc, mstorsjo, ldionne
Differential Revision: https://reviews.llvm.org/D104987
We always build the libraries in a Standard mode that supports noexcept,
so there's no need to use the _NOEXCEPT macro.
Differential Revision: https://reviews.llvm.org/D97700
We need CLOCK_MONOTONIC equivalent implementation for z/OS within libc++. The default implementation is asserting.
On z/OS the lack of 'clock_gettime()' and 'time_point()' force us to look for alternatives.
The current proposal is to use `gettimeofday()` for CLOCK_MONOTONIC which is also used in CLOCK_REALTIME. This will allow us to skip the assertion with compromised CLOCK_MONOTONIC implementation which will not guarantee to never go back in time because it will use `gettimeofday()` but only when it's set.
Is this a good compromise for platforms which does not support monotonic clock?
Hopefully this will spark the discussion and agreement how to proceed in this situation.
Reviewed By: #libc, ldionne, hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D93542
The clock_gettime function is available when _POSIX_TIMERS is defined.
We check for this and set _LIBCPP_USE_CLOCK_GETTIME accordingly since
59b3102739c. But check for _LIBCPP_USE_CLOCK_GETTIME was removed in
babd3aefc91. As a result, code is now trying to use clock_gettime even
on platforms where it is not available and it is causing build failure
with newlib.
This patch restores the checks to fix this.
Differential Revision: https://reviews.llvm.org/D88825
This increases the Mac OS requirement for building libc++ to 10.12.
Note that it doesn't change whether the *headers* still support older
platforms -- it's only that macOS >= 10.12 is required to build the
dylib from sources.
Differential Revision: https://reviews.llvm.org/D74489
unistd.h isn't guaranteed to exist when the target isn't Windows, in
particular if the target is bare-metal (i.e. no operating system).
Handle this by using __has_include instead, though in
filesystem/operations.cpp we already unconditionally include it so
just remove the extra include.
Differential Revision: https://reviews.llvm.org/D79784
clock_gettime is documented to be available when _POSIX_TIMERS is
defined. Add a check for this.
Differential Revision: https://reviews.llvm.org/D79305
Summary:
In D27429, we switched the Apple implementation of steady_clock::now()
from clock_gettime(CLOCK_MONOTONIC) to clock_gettime(CLOCK_UPTIME_RAW).
The purpose was to get nanosecond precision, and also to improve the
performance of the implementation.
However, it appears that CLOCK_UPTIME_RAW does not satisfy the requirements
of the Standard, since it is not strictly speaking monotonic. Indeed, the
clock does not increment while the system is asleep, which had been
mentioned in D27429 but somehow not addressed.
This patch switches to CLOCK_MONOTONIC_RAW, which is monotonic, increased
during sleep, and also has nanosecond precision.
https://llvm.org/PR44773
Reviewers: bruno, howard.hinnant, EricWF
Subscribers: christof, jkorous, dexonsmith, libcxx-commits, mclow.lists, EricWF
Tags: #libc
Differential Revision: https://reviews.llvm.org/D74341
This is a followup to 35bc5276ca3. It fixes the dependent libs usage
in libcxx and libcxxabi to link pthread and rt libraries only if CMake
detects them, rather than based on explicit platform blacklist.
Differential Revision: https://reviews.llvm.org/D70888
r362048 added support for ELF dependent libraries, but broke Android
build since Android does not have libpthread. Remove the dependency on
the Android build.
Differential Revision: https://reviews.llvm.org/D65098
llvm-svn: 366734
This fixes the issue introduced by r362048 where we always use
pragma comment(lib, ...) for dependent libraries when the compiler
is Clang, but older Clang versions don't support this pragma so
we need to check first if it's supported before using it.
llvm-svn: 362055
As of r360984, LLD supports dependent libraries feature for ELF.
libunwind, libc++abi and libc++ have library dependencies: libdl librt
and libpthread, which means that when libunwind and libc++ are being
statically linked (using -static-libstdc++ flag), user has to manually
specify -ldl -lpthread which is onerous.
This change includes the lib pragma to specify the library dependencies
directly in the source that uses those libraries. This doesn't make any
difference when using linkers that don't support dependent libraries.
However, when using LLD that has dependent libraries feature, users no
longer have to manually specifying library dependencies when using
static linking, linker will pick the library automatically.
Differential Revision: https://reviews.llvm.org/D62090
llvm-svn: 362048
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:
The ``file_time_type`` time point is used to represent the write times for files.
Its job is to act as part of a C++ wrapper for less ideal system interfaces. The
underlying filesystem uses the ``timespec`` struct for the same purpose.
However, the initial implementation of ``file_time_type`` could not represent
either the range or resolution of ``timespec``, making it unsuitable. Fixing
this requires an implementation which uses more than 64 bits to store the
time point.
I primarily considered two solutions: Using ``__int128_t`` and using a
arithmetic emulation of ``timespec``. Each has its pros and cons, and both
come with more than one complication.
However, after a lot of consideration, I decided on using `__int128_t`. This patch implements that change.
Please see the [FileTimeType Design Document](http://libcxx.llvm.org/docs/DesignDocs/FileTimeType.html) for more information.
Reviewers: mclow.lists, ldionne, joerg, arthur.j.odwyer, EricWF
Reviewed By: EricWF
Subscribers: christof, K-ballo, cfe-commits, BillyONeal
Differential Revision: https://reviews.llvm.org/D49774
llvm-svn: 337960
Use CLOCK_UPTIME_RAW in case clock_gettime is available on Darwin.
On Apple platforms only CLOCK_UPTIME_RAW or mach_absolute_time are able
to time functions in the nanosecond range. Thus, they are the only
acceptable implementations of steady_clock.
Differential Revision: https://reviews.llvm.org/D27429
rdar://problem/29449467
llvm-svn: 291466
Replace the use of _WIN32 in libc++. Replace most use with a C runtime
check _LIBCPP_MSVCRT or the new _LIBCPP_WIN32 to indicate that we are
using the Win32 API. Use a new _LIBCPP_WCHAR_IS_UCS2 to indicate that we
are on an environment that has a short wchar_t.
llvm-svn: 290910
As pointed out by Howard, this is actually 134774 days (* 24 * 3600),
and therefore seconds, not 100ns units. Adjust the units to reflect
reality.
llvm-svn: 290824
Drawing some inspiration from code from Bill O'Neal as pointed out by
Howard, rework the code to avoid an overflow in the duration. Adjust
the style to match libc++ style as well.
Create a local typedef for the FILETIME duration (100-ns units). Use
this to define the difference between the NT and the UNIX epochs (which
previously overflowed due to the representation limits due to the
bouncing to ns). Return the FILETIME duration biased by the NT-to-UNIX
epoch conversion.
Use of the custom duration makes it easier to read and reason about the
code.
llvm-svn: 290806
