Since we expect the condition to be true most of the time, we might
as well tell the compiler. And when assertions are disabled, we
might as well tell the compiler that it's allowed to assume that
the condition holds.
Differential Revision: https://reviews.llvm.org/D122397
Instead of using a temporary `string` in `__vformat_to_wrapped` use a new
generic iterator. This aids to reduce the number of template instantions
and avoids using a `string` to buffer the entire formatted output.
This changes the type of `format_context` and `wformat_context`, this can
still be done since the code isn't ABI stable yet.
Several approaches have been evaluated:
- Using a __output_buffer base class with:
- a put function to store the buffer in its internal buffer
- a virtual flush function to copy the internal buffer to the output
- Using a `function` to forward the output operation to the output buffer,
much like the next method.
- Using a type erased function point to store the data in the buffer.
The last version resulted in the best performance. For some cases there's
still a loss of speed over the original method. This loss many becomes
apparent when large strings are copied to a pointer like iterator, before
the compiler optimized this using `memcpy`.
Reviewed By: ldionne, vitaut, #libc
Differential Revision: https://reviews.llvm.org/D110495
I suspect this is a remnant of the times when we were not comfortable
using Clang's C++11/14 extensions everywhere, but now we do, so we can
use _BoolConstant instead and get rid of the macro.
Differential Revision: https://reviews.llvm.org/D122351
In C++20 the type trait `type_identity` was introduced. For the same purpose there is `__identity` for pre-C++20 code. The name is confusing, because since C++20 there is also `identity`, which isn't a type trait.
Reviewed By: ldionne, Mordante, #libc
Spies: EricWF, libcxx-commits
Differential Revision: https://reviews.llvm.org/D122017
I audited all uses of _LIBCPP_ASSERT to make sure that we only used it
for "basic assertions", i.e. assertions with constant-time conditions.
I also audited all uses of _LIBCPP_DEBUG_ASSERT to make sure we used it
only for debug-mode assertions, and in one case had to change for
_LIBCPP_ASSERT instead.
As a fly-by, I also changed a couple of tests against nullptr or 0 to
be more explicit.
After this patch, all uses of _LIBCPP_ASSERT should be with constant-time
conditions, and all uses of _LIBCPP_DEBUG_ASSERT should be with conditions
that we only want to check when the debug mode is enabled.
Differential Revision: https://reviews.llvm.org/D122395
This patch adds a lightweight assertion handler mechanism that can be
overriden at link-time in a fashion similar to `operator new`.
This is a third take on https://llvm.org/D121123 (which allowed customizing
the assertion handler at compile-time), and https://llvm.org/D119969
(which allowed customizing the assertion handler at runtime only).
This approach is, I think, the best of all three explored approaches.
Indeed, replacing the assertion handler in user code is ergonomic,
yet we retain the ability to provide a custom assertion handler when
deploying to older platforms that don't have a default handler in
the dylib.
As-is, this patch provides a pretty good amount of backwards compatibility
with the previous debug mode:
- Code that used to set _LIBCPP_DEBUG=0 in order to get basic assertions
in their code will still get basic assertions out of the box, but
those assertions will be using the new assertion handler support.
- Code that was previously compiled with references to __libcpp_debug_function
and friends will work out-of-the-box, no changes required. This is
because we provide the same symbols in the dylib as we used to.
- Code that used to set a custom __libcpp_debug_function will stop
compiling, because we don't provide that declaration anymore. Users
will have to migrate to the new way of setting a custom assertion
handler, which is extremely easy. I suspect that pool of users is
very limited, so breaking them at compile-time is probably acceptable.
The main downside of this approach is that code being compiled with
assertions enabled but deploying to an older platform where the assertion
handler didn't exist yet will fail to compile. However users can easily
fix the problem by providing a custom assertion handler and defining
the _LIBCPP_AVAILABILITY_CUSTOM_ASSERTION_HANDLER_PROVIDED macro to
let the library know about the custom handler. In a way, this is
actually a feature because it avoids a load-time error that one would
otherwise get when trying to run the code on the older target.
Differential Revision: https://reviews.llvm.org/D121478
See https://reviews.llvm.org/D121626 for details -- this re-enables the
CTAD we removed, since it does break some stuff as well (even though it's
not nearly as bad as the removed constructors fixed by D121626).
Differential Revision: https://reviews.llvm.org/D122184
Addresses LWG 3548 which mandates that when shared_ptr is being constructed from a unique_ptr, the unique_ptr's deleter should be moved and not copied.
Reviewed By: #libc, philnik, EricWF
Differential Revision: https://reviews.llvm.org/D119159
Changes in [P0896](https://wg21.link/p0896):
- add `disable_sized_sentinel_for`;
- add `iter_move` and `iter_swap`;
- add a `requires` clause to the `operator->`;
- add `iterator_concept`;
- check that the `Iterator` template parameter is a bidirectional
iterator;
- add constraints to all comparison operators;
- change the definitions of `iterator_category`, `value_type`,
`difference_type` and `reference` (changes to `iterator_category` were
already implemented).
Also add a few forgotten things to the `reverse_iterator` synopsis
(notably the spaceship operator).
Differential Revision: https://reviews.llvm.org/D120180
In 7fb40e1569, I changed the availability for bad_optional_access and
friends from macOS 10.14 to 10.13 after conducting an investigation on
old dylibs. It turns out that macOS 10.13 did have bad_optional_access,
however the dylib on iOS didn't match the dylib on macOS, so those
exception classes were only introduced in iOS 12.
Thanks to Aditya Kumar for noticing this.
Differential Revision: https://reviews.llvm.org/D121735
This should make CI consistent on all the compilers we support. Most of
this patch is working around various warnings emitted by GCC in our code
base, which are now being shown when we compile the tests.
After this patch, the whole test suite should be warning free on all
compilers we support and test, except for a few warnings on GCC that
we silence explicitly until we figure out the proper fix for them.
Differential Revision: https://reviews.llvm.org/D120684
Back in 3a208c6894, we implemented the range-based constructor for <span>.
However, in doing so, we removed a previous non-standard constructor that
we provided before shipping <ranges>. Unfortunately, that breaks code that
was relying on a range-based constructor until we ship all of <ranges>.
This patch reintroduces the old non-conforming constructors and tests
that were removed in 3a208c6894 and uses them whenever <ranges> is
not provided (e.g. in LLVM 14). This is only a temporary workaround
until we enable <ranges> by default in C++20, which should hopefully
happen by LLVM 15.
The goal is to cherry-pick this workaround back to the LLVM 14 release
branch, since I suspect the constructor removal may otherwise cause
breakage out there, like the breakage I saw internally.
We could have avoided this situation by waiting for C++20 to be finalized
before shipping std::span. For example, we could have guarded it with
something like _LIBCPP_HAS_NO_INCOMPLETE_RANGES to prevent users from
accidentally starting to depend on it before it is stable. We did not
have these mechanisms when std::span was first implemented, though.
Differential Revision: https://reviews.llvm.org/D121626
The class `__dir_stream` is currently declared in two places: as a
top-level forward declaration in `directory_iterator.h`, and as a friend
declaration in class `directory_entry`, in `directory_entry.h`.
The former has a `_LIBCPP_HIDDEN` attribute, but the latter does not,
causing the Firefox build to complain about the visibility not matching
the previous declaration. This is because Firefox plays games with
pushing and popping visibility.
Work around this by making both `__dir_stream` declarations consistently
use `_LIBCPP_HIDDEN`.
Reviewed By: ldionne, philnik, #libc
Differential Revision: https://reviews.llvm.org/D121639
It turns out that the whole header is only enabled in C++20 and above,
so these checks were redundant (and always true).
Differential Revision: https://reviews.llvm.org/D121604
All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBCPP_STD_VER > 17`. Similarly in
the tests, remove `// UNSUPPORTED: libcpp-no-concepts`.
Differential Revision: https://reviews.llvm.org/D121528
We don't need preprocessor logic to exclude those declarations when compiling for
the Windows App Store, because that is handled by using_if_exists now.
Differential Revision: https://reviews.llvm.org/D108632
Instead of carrying around #ifdefs to determine whether those functions
are available on the platform, unconditionally use the using_if_exists
attribute to import it into namespace std only when available. That was
the purpose of this attribute from the start.
This change means that trying to use libc++ with an old SDK (or on an
old platform for platforms that ship system headers in /usr/include)
will require a recent Clang that supports the using_if_exists attribute.
When using an older Clang or GCC, the underlying platform has to support
a C11 standard library.
Differential Revision: https://reviews.llvm.org/D108203
As a fly-by fix, also move it closer to where it is needed, and add a
comment explaining the existence of this weird function.
Differential Revision: https://reviews.llvm.org/D121231
This reverts commit 276ca873. That commit has quite a history at this
point. It was first landed in dbc647643577, which broke std::shared_ptr<T const>
and was reverted in 9138666f5. It was then re-applied in 276ca873, with
the std::shared_ptr issue fixed, but it caused widespread breakage at
Google (which suggests it would cause similar breakage in the wild too),
so now I'm reverting again.
Instead, I will add a escape hatch that vendors can turn on to enable
the extension and perform a phased transition over one or two releases
like we sometimes do when things become non-trivial.
Based on review comments in D97705 applied some code cleanups in
<charconv>. The header now uses a more recent libc++ style.
Reviewed By: Quuxplusone, #libc, philnik
Differential Revision: https://reviews.llvm.org/D121223
This extension is a portability trap for users, since no other standard
library supports it. Furthermore, the Standard explicitly allows
implementations to reject std::allocator<cv T>, so allowing it is
really going against the current.
This was discovered in D120684: this extension required `const_cast`ing
in `__construct_range_forward`, a fishy bit of code that can be removed
if we don't support the extension anymore.
This is a re-application of dbc647643577, which was reverted in 9138666f5
because it broke std::shared_ptr<T const>. Tests have now been added and
we've made sure that std::shared_ptr<T const> wouldn't be broken in this
version.
Differential Revision: https://reviews.llvm.org/D120996
As a fly-by fix, enable the complexity-changing assertions in __debug_less
only when the full debug mode is enabled, since debugging level 0 is usually
understood to only contain basic assertions that do not change the complexity
of algorithms.
Differential Revision: https://reviews.llvm.org/D121129
Saves one move in each case, which is basically nothing perf-wise;
this is more about simplifying the code.
Differential Revision: https://reviews.llvm.org/D121130
This extension is a portability trap for users, since no other standard
library supports it. Furthermore, the Standard explicitly allows
implementations to reject std::allocator<cv T>, so allowing it is
really going against the current.
This was discovered in D120684: this extension required `const_cast`ing
in `__construct_range_forward`, a fishy bit of code that can be removed
if we don't support the extension anymore.
Differential Revision: https://reviews.llvm.org/D120996
Move `__quoted_output_proxy` into the one file that uses it.
A `const char*` has no associated traits class, so `std::quoted("literal")`
should be printable into any basic_ostream regardless of traits.
Use hidden-friend `operator<<` and `operator>>`, since we're permitted to.
(The exact signature is unspecified because the class itself is unspecified.)
We shouldn't support `std::quoted("literal")` in C++03 or C++11 mode.
(We do need `std::__quoted(s)` and `std::__quoted(cs)` in C++11 mode,
because they're used by `std::__fs::filesystem::path`.)
Differential Revision: https://reviews.llvm.org/D120135
Zero-sized types are a GCC extension, also supported by Clang.
In theory it's already invalid to `delete` a void pointer or a
pointer-to-incomplete, so we shouldn't need any special code
to catch those cases; but in practice Clang accepts both
constructs with just a warning, and GCC even accepts `sizeof(void)`
with just a warning! So we must keep the static_asserts.
The hard errors are tested in `unique_ptr_dltr_dflt/*.compile.fail.cpp`.
In ranges::begin/end, check `sizeof >= 0` instead of `sizeof != 0`,
so as to permit zero-sized types while still disallowing incomplete
types.
Fixes#54100.
Differential Revision: https://reviews.llvm.org/D120633
This change makes the behavior of `<experimental/coroutine>` consistent with other headers that only work conditionally.
Reviewed By: ldionne, #libc
Spies: Mordante, ChuanqiXu, libcxx-commits, arichardson
Differential Revision: https://reviews.llvm.org/D119964
Previously, this test snippet would report incorrect information:
F::mask m;
std::wstring in(L"\u00DA"); // LATIN CAPITAL LETTER U WITH ACUTE
f.is(in.data(), in.data() + 1, &m);
// m & F::lower would be set
The single-character version of the `is` function wasn't
affected by this issue though.
Define `_LIBCPP_CTYPE_MASK_IS_COMPOSITE_ALPHA` for Windows,
as the `alpha` / `_ALPHA` constant is a mask consisting of
multiple bits set, which avoids setting `alpha` whenver any
of the bits is set, in the `do_is` implementation.
On Windows, with the "C" locale, wchars are classified according
to their Unicode interpretation, just as in the en_US.UTF-8 locale on
all platforms.
Due to the differing classification of some characters, the
`scan_is` and `scan_not` tests are quite annoying to fix, thus just
ifdef out some of the tests for the "C" locale there - the code gets
tested with the more standard en_US.UTF-8 locale anyway.
Differential Revision: https://reviews.llvm.org/D120796
Fixes LWG3656, "Inconsistent bit operations returning a count".
https://cplusplus.github.io/LWG/issue3656
The fix has been approved for C++23 and left to vendors' discretion
in C++20 (but it sounds like everyone's on the same page that
of course it should be DR'ed back to C++20 too).
Differential Revision: https://reviews.llvm.org/D120444
Louis Dionne