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.
Some embedded platforms do not wish to support the C library functionality
for handling wchar_t because they have no use for it. It makes sense for
libc++ to work properly on those platforms, so this commit adds a carve-out
of functionality for wchar_t.
Unfortunately, unlike some other carve-outs (e.g. random device), this
patch touches several parts of the library. However, despite the wide
impact of this patch, I still think it is important to support this
configuration since it makes it much simpler to port libc++ to some
embedded platforms.
Differential Revision: https://reviews.llvm.org/D111265
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
These [[nodiscard]] annotations are added as a conforming extension;
it's unclear whether the paper will actually be adopted and make them
mandatory, but they do seem like good ideas regardless.
https://isocpp.org/files/papers/D2351R0.pdf
This patch implements the paper's effect on:
- std::to_integer, std::to_underlying
- std::forward, std::move, std::move_if_noexcept
- std::as_const
- std::identity
The paper also affects (but libc++ does not yet have an implementation of):
- std::bit_cast
Differential Revision: https://reviews.llvm.org/D99895
Always depend on the compiler to have a correct implementation of
max_align_t in stddef.h and don't provide a fallback. For pre-C++11,
require __STDCPP_NEW_ALIGNMENT__ in <new> as provided by clang in all
standard modes. Adjust test cases to avoid testing or using max_align_t
in pre-C++11 mode and also to better deal with alignof(max_align_t)>16.
Document requirements of the alignment tests around natural alignment of
power-of-two-sized types.
Differential revision: https://reviews.llvm.org/D73245
Depend on the compiler to provide a correct implementation of
max_align_t. If __STDCPP_NEW_ALIGNMENT__ is missing and C++03 mode has
been explicitly enabled, provide a minimal fallback in <new> as
alignment of the largest primitive types.
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 NetBSD headers ship with max_align_t, that is not
compatible with the fallback version in libc++.
There is no defined a compiler specific symbol in the headers like:
- __CLANG_MAX_ALIGN_T_DEFINED
- _GCC_MAX_ALIGN_T
- __DEFINED_max_align_t
Sponsored by <The NetBSD Foundation>
Reviewers: chandlerc, dlj, EricWF, joerg
Reviewed By: joerg
Subscribers: bsdjhb, llvm-commits, cfe-commits
Differential Revision: https://reviews.llvm.org/D47814
llvm-svn: 340224
Summary:
Libcxx will define its own max_align_t when it is not available. However, the
availability checks today only check for Clang's definition and GCC's
definition. In particular, it does not check for musl's definition, which is the
same as GCC's but guarded with a different macro.
Reviewers: mclow.lists, EricWF
Reviewed By: EricWF
Subscribers: chandlerc, cfe-commits
Differential Revision: https://reviews.llvm.org/D28478
llvm-svn: 294683
There are a bunch of macros (__need_size_t etc) that request just one piece of
<stddef.h>; if any one of these is defined, we just directly include the
underlying header.
Note that <stddef.h> provides a ::nullptr_t. We don't want that available to
includers of <cstddef>, so instead of following the usual pattern where <cfoo>
includes <foo.h> then pulls things from :: into std:: with using-declarations,
we implement <stddef.h> and <cstddef> separately; both include <__nullptr> for
the definition of std::nullptr_t.
llvm-svn: 249761
r207606 changed the __need_foo macros to behave like they do with gcc: If they
are set, _only_ the __need_foo stuff gets defined. As a consequence, cstddef
no longer defined "offsetof". It looks like the __need_foo defines aren't
needed anymore, so just remove them.
Fixes PR19723.
llvm-svn: 208942
rather than its own type for std::max_align_t. This is particularly
relevant as the types may not be ABI compatible despite users expecting
them to be.
llvm-svn: 201843
Louis Dionne