Broke builders that emit different diagnostics. e.g.:
error: 'warning' diagnostics seen but not expected:
Line 13: alias declarations are a C++11 extension
Line 20: alias declarations are a C++11 extension
This reverts commit ff87813715.
Summary: This review is a mostly trivial change to use an explicit ABI flag for the unstable external template list. This follows the practice for an ABI flag per feature, and provides a spot for the rational / motivation for the flag.
Reviewers: EricWF, ldionne
Subscribers: dexonsmith, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D75457
The markup wasn't quite right, and that broke compilation with availability
markup enabled. I'm disabling it until I have time to fix it properly to
get the CI mostly green again.
Summary:
This change adds the macros _LIBCPP_COMPILER_HAS_BUILTIN_CONSTANT and _LIBCPP_BUILTIN_CONSTANT_P to detect compile time constants, and optimze the code accordingly.
A planned usage example:
The implementation of basic_string::assign() can short-cut a compile time known short string assignent into a fast and compact inlined assignment:
```
basic_string::assign(const value_type* __s) {
if (_LIBCPP_BUILTIN_CONSTANT_P(__s[0]) && length(__s) < __min_cap) {
copy(pointer(), _s, length(__s) + 1);
set_size(length(__s));
} else {
// delegate / tail call out of line implementation
}
}
```
Subscribers: christof, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D73732
- Add the new symbols to the ABI list on Darwin
- Add XFAIL markup to the tests that require dylib support on older platforms
- Add availability markup for back-deployment
Summary:
FreeBSD got `timespec_get` support somewhere in the 12.x timeframe, but
the C++ version check in its system headers was written incorrectly.
This has now been fixed for both FreeBSD 13 and 12.
Add checks for the corresponding `__FreeBSD_version` values, to define
`_LIBCPP_HAS_TIMESPEC_GET` when the function is supported.
Reviewers: emaste, EricWF, ldionne, mclow.lists
Reviewed By: ldionne
Subscribers: arichardson, krytarowski, christof, dexonsmith, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D71522
Summary:
The libcxx test suite auto-detects spaceship operator, but __config does not. This means that the libcxx test suite has been broken for over a month when using top-of-tree clang. This also really ought to be fixed before 10.0.
See: bc633a42dd
Reviewers: chandlerc, mclow.lists, EricWF, ldionne, CaseyCarter
Reviewed By: EricWF
Subscribers: broadwaylamb, hans, dexonsmith, tstellar, llvm-commits, libcxx-commits
Tags: #libc, #llvm
Differential Revision: https://reviews.llvm.org/D72980
Summary:
The compiler already treats them as scalar types, so the library should
too. Furthermore, this allows blocks to be used in more places, for
example in std::optional, which requires an object type.
rdar://problem/57892832
Reviewers: dexonsmith, EricWF, mclow.lists
Differential Revision: https://reviews.llvm.org/D72708
We switched to C11 thread API on Fuchsia in ab9aefe, but further
testing showed that Fuchsia's C11 mutex implementation needs a few
improvements for this to be usable, so we temporarily switch back
to the pthread implementation until those issues are addressed.
Differential Revision: https://reviews.llvm.org/D72862
The GCC build failures have been addressed, and the LLDB failures were
fixed by LLDB.
I have also verified that the apple-clang 9.0 segfault no longer
occurs.
Original Message:
The external instantiation of std::string is a problem for libc++.
Additions and removals of inline functions in string can cause ABI
breakages, including introducing new symbols.
This patch aims to:
(1) Make clear which functions are explicitly instatiated.
(2) Prevent new functions from being accidentally instantiated.
(3) Allow a migration path for adding or removing functions from the
explicit instantiation over time.
Although this new formulation is uglier, it is preferable from a
maintainability and readability standpoint because it explicitly
enumerates the functions we've chosen to expose in our ABI. Changing
this list is non-trivial and requires thought and planning.
(3) is achieved by making it possible to control the extern template declaration
separately from it's definition. Meaning we could add a new definition to
the dylib, wait for it to roll out, then add the extern template
declaration to the header. Similarly, we could remove existing extern
template declarations while still keeping the definition to prevent ABI
breakages.
On Fuchsia, pthread API is emulated on top of C11 thread API. Using C11
thread API directly is more efficient.
While this implementation is only used by Fuchsia at the moment, it's
not Fuchsia specific, and could be used by other platforms that use C11
threads rather than pthreads in the future.
Differential Revision: https://reviews.llvm.org/D64378
The external instantiation of std::string is a problem for libc++.
Additions and removals of inline functions in string can cause ABI
breakages, including introducing new symbols.
This patch aims to:
(1) Make clear which functions are explicitly instatiated.
(2) Prevent new functions from being accidentally instantiated.
(3) Allow a migration path for adding or removing functions from the
explicit instantiation over time.
Although this new formulation is uglier, it is preferable from a
maintainability and readability standpoint because it explicitly
enumerates the functions we've chosen to expose in our ABI. Changing
this list is non-trivial and requires thought and planning.
(3) is achieved by making it possible to control the extern template declaration
separately from it's definition. Meaning we could add a new definition to
the dylib, wait for it to roll out, then add the extern template
declaration to the header. Similarly, we could remove existing extern
template declarations while still keeping the definition to prevent ABI
breakages.
Summary:
`__has_attribute(fallthough)` -> `__has_attribute(fallthrough)`
This is a follow-up of https://reviews.llvm.org/D72287
Reviewers: EricWF, mclow.lists, Jim
Reviewed By: Jim
Subscribers: christof, ldionne, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D72314
Add NetBSD to the same feature list as Fuchsia since it matches
in available features, effectively enabling aligned_alloc(),
timespec_get() and C11 features. Remove now-duplicate declaration
of quick_exit() support.
Differential Revision: https://reviews.llvm.org/D71511
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
Summary:
In D67316 we added `_LIBCPP_C_HAS_NO_GETS` to signal that the C library
does not provide `gets()`, and added a test for FreeBSD 13 or higher,
using the compiler-defined `__FreeBSD__` macro.
Unfortunately this did not work that well for FreeBSD's own CI process,
since the gcc compilers used for some architectures define `__FreeBSD__`
to match the build host, not the target.
Instead, we should use the `__FreeBSD_version` macro from the userland
header `<osreldate.h>`, which is more fine-grained. See also
<https://reviews.freebsd.org/D22034>.
Reviewers: EricWF, mclow.lists, emaste, ldionne
Reviewed By: emaste, ldionne
Subscribers: dexonsmith, bsdjhb, krytarowski, christof, ldionne, libcxx-commits
Differential Revision: https://reviews.llvm.org/D69174
llvm-svn: 375340
Summary: The implementation of P1152R4 in Clang has resulted in some deprecation warnings appearing in the libc++ and libc++abi test suite. Fix or suppress these warnings.
Reviewers: mclow.lists, EricWF
Subscribers: christof, ldionne, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D68879
llvm-svn: 375307
std::condition_variable is currently implemented via
pthread_cond_timedwait() on systems that use pthread. This is
problematic, since that function waits by default on CLOCK_REALTIME
and libc++ does not provide any mechanism to change from this
default.
Due to this, regardless of if condition_variable::wait_until() is
called with a chrono::system_clock or chrono::steady_clock parameter,
condition_variable::wait_until() will wait using CLOCK_REALTIME. This
is not accurate to the C++ standard as calling
condition_variable::wait_until() with a chrono::steady_clock parameter
should use CLOCK_MONOTONIC.
This is particularly problematic because CLOCK_REALTIME is a bad
choice as it is subject to discontinuous time adjustments, that may
cause condition_variable::wait_until() to immediately timeout or wait
indefinitely.
This change fixes this issue with a new POSIX function,
pthread_cond_clockwait() proposed on
http://austingroupbugs.net/view.php?id=1216. The new function is
similar to pthread_cond_timedwait() with the addition of a clock
parameter that allows it to wait using either CLOCK_REALTIME or
CLOCK_MONOTONIC, thus allowing condition_variable::wait_until() to
wait using CLOCK_REALTIME for chrono::system_clock and CLOCK_MONOTONIC
for chrono::steady_clock.
pthread_cond_clockwait() is implemented in glibc (2.30 and later) and
Android's bionic (Android API version 30 and later).
This change additionally makes wait_for() and wait_until() with clocks
other than chrono::system_clock use CLOCK_MONOTONIC.<Paste>
llvm-svn: 372016
Summary:
In https://svnweb.freebsd.org/changeset/base/351659 @emaste removed gets() from
FreeBSD 13's libc, and our copies of libc++ and libstdc++. In that change, the
declarations were simply deleted, but I would like to propose this conditional
test instead.
Reviewers: EricWF, mclow.lists, emaste
Reviewed By: mclow.lists
Subscribers: krytarowski, christof, ldionne, emaste, libcxx-commits
Differential Revision: https://reviews.llvm.org/D67316
llvm-svn: 371324
In r292833, we started defining _LIBCPP_CLANG_VER to 0 for Apple Clang.
The result is that AppleClang is detected as being a very old version
of LLVM Clang (version 0), which is obviously incorrect.
I believe this was added so that we don't have to check whether
_LIBCPP_CLANG_VER is defined prior to comparing it with a number
(which can trigger a warning). This commit also fixes the two
places that use the macro correspondingly.
llvm-svn: 368880
There are a handful of standard library types that are intended
to support CTAD but don't need any explicit deduction guides to
do so.
This patch adds a dummy deduction guide to those types to suppress
-Wctad-maybe-unsupported (which gets emitted in user code).
llvm-svn: 367770
[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
The implementations of __libcpp_mutex_destroy and __libcpp_condvar_destroy
are already NOPs, so this optimization is safe to perform.
See r365273 and PR27658 for more information.
llvm-svn: 365281
Currently std::mutex has a constexpr constructor, but a non-trivial
destruction.
The constexpr constructor is required to ensure the construction of a
mutex with static storage duration happens at compile time, during
constant initialization, and not during dynamic initialization.
This means that static mutex's are always initialized and can be used
safely during dynamic initialization without the "static initialization
order fiasco".
A trivial destructor is important for similar reasons. If a mutex is
used during dynamic initialization it might also be used during program
termination. If a static mutex has a non-trivial destructor it will be
invoked during termination. This can introduce the "static
deinitialization order fiasco".
Additionally, function-local statics emit a guard variable around
non-trivially destructible types. This results in horrible codegen and
adds a runtime cost to every call to that function. non-local static's
also result in slightly worse codegen but it's not as big of a problem.
Example codegen can be found here: https://goo.gl/3CSzbM
Note: This optimization is not safe with every pthread implementation.
Some implementations allocate on the first call to pthread_mutex_lock
and free the allocation in pthread_mutex_destroy.
Also, changing the triviality of the destructor is not an ABI break.
At least to the best of my knowledge :-)
llvm-svn: 365273
when _LIBCPP_ABI_UNSTABLE is defined.
User defined _LIBCPP_ABI_NAMESPACE will still be respected,
but the default version namespace in unstable mode will be the libc++ version
(Currently '__9000').
Previously `_LIBCPP_ABI_VERSION` and `_LIBCPP_ABI_NAMESPACE` were
`1` and `__1` respectively, whuch conflicted with the stable ABI
llvm-svn: 364354
All the compilers we support provide these builtins. We don't
need to do a configuration dance anymore.
This patch also cleans up some dead or almost dead
C++11 feature detection macros.
llvm-svn: 364047
Summary:
This patch make G++03 explicitly unsupported with libc++, as discussed on the mailing lists.
Below is the rational for this decision.
----------------------------------------------------------------------------------------------------
libc++ claims to support GCC with C++03 ("G++03"), and this is a problem for our users.
Our C++03 users are all using Clang. They must be. Less than 9% of the C++03 tests pass with GCC [1][2]. No non-trivial C++ program could work.
Attempting to support G++03 impacts our QoI considerably. Unlike Clang, G++03 offers almost no C++11 extensions. If we could remove all the fallbacks for G++03, it would mean libc++ could::
* Improve Correctness:
Every `#ifdef _LIBCPP_HAS_NO_<C++11-feature>` is a bug manifest. It exists to admit for deviant semantics.
* Achieve ABI stability between C++03 and C++11
Differences between our C++03 and C++Rest branches contain ABI bugs. For example `std::nullptr_t` and `std::function::operator()(...)` are currently incompatible between C++11 and C++03, but could be fixed.
* Decrease Compile Times and Memory Usage:
Writing efficient SFINAE requires C++11. Using alias templates, libc++ could reduce the number of instantiations it produces substantially.
* Decrease Binary Size
Similar to the last point, G++03 forces metaprogramming techniques that emit more debug information [3] [4]. Compared to libstdc++, debug information size increases of +10% are not uncommon.
Reviewers: ldionne, mclow.lists, EricWF
Reviewed By: ldionne, EricWF
Subscribers: zoecarver, aprantl, dexonsmith, arphaman, libcxx-commits, #libc
Differential Revision: https://reviews.llvm.org/D63154
llvm-svn: 363219
When applied to a typedef or alias template, the [[nodebug]] attribute
makes the typedef transparent to the debugger, so instead of seeing
`std::__function::__alloc_func<remove_reference<void(&)()>::type,
allocator<remove_reference<void(&)()>, void()>::_Target` you see
`void(&)()` as the type of the variable in your debugger.
Removing all this SFINAE noise from debug info has huge binary size
wins, in addition to improving the readability.
For now this change is on by default. Users can override it by
specifying -D_LIBCPP_NODEBUG_TYPE=
llvm-svn: 363117
std::function uses a standard allocator to manage its memory, however
standard allocators are templates and using them correctly requires
a stupid amount of instantiations. This leads to a substantial increase
in debug info and object sizes.
This patch addresses the issue by dropping the allocator when possible
and using raw new and delete to get memory.
This change decreases the object file size for the test func.wrap.func.con/F.pass.cpp by 33% and the final binary by 29% (when compiled with -g -ggnu-pubnames -gpubnames).
It also roughly halfs the number of entries in the pubnames and pubtype
sections.
llvm-svn: 362865
merged type info names.
Previously std::type_info always expected type info string to be unique.
But this isn't always the case. Like when -Bsymbolic is passed to the
linker or due to llvm.org/PR37398.
This patch adds the LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT CMake
option which, when specified, overrides the default configuration for
the library.
The current defaults still assume unique names even though this isn't
strictly correct for ELF binaries. We should consider changing the
default in a follow up commit.
llvm-svn: 361913
Dan Albert