Currently, the library-internal feature test macros are only defined if
the feature is not available, and always have the prefix
`_LIBCPP_HAS_NO_`. This patch changes that, so that they are always
defined and have the prefix `_LIBCPP_HAS_` instead. This changes the
canonical use of these macros to `#if _LIBCPP_HAS_FEATURE`, which means
that using an undefined macro (e.g. due to a missing include) is
diagnosed now. While this is rather unlikely currently, a similar change
in `<__configuration/availability.h>` caught a few bugs. This also
improves readability, since it removes the double-negation of `#ifndef
_LIBCPP_HAS_NO_FEATURE`.
The current patch only touches the macros defined in `<__config>`. If
people are happy with this approach, I'll make a follow-up PR to also
change the macros defined in `<__config_site>`.
In essence, this header has always been related to configuration of
the library but we didn't want to put it inside <__config> due to
complexity reasons. Now that we have sub-headers in <__config>, we
can move <__availability> to it and stop including it everywhere since
we already obtain the required macros via <__config>.
<filesystem> is a C++17 addition. In C++11 and C++14 modes, we actually
have all the code for <filesystem> but it is hidden behind a non-inline
namespace __fs so it is not accessible. Instead of doing this unusual
dance, just guard the code for filesystem behind a classic C++17 check
like we normally do.
Since LIBCXX_ENABLE_FILESYSTEM now truly represents whether the
platform supports a filesystem (as opposed to whether the <filesystem>
library is provided), we can provide a few additional classes from
the <filesystem> library even when the platform does not have support
for a filesystem. For example, this allows performing path manipulations
using std::filesystem::path even on platforms where there is no actual
filesystem.
rdar://107061236
Differential Revision: https://reviews.llvm.org/D152382
These macros are always defined identically, so we can simplify the code a bit by merging them.
Reviewed By: ldionne, #libc
Spies: libcxx-commits, krytarowski, smeenai
Differential Revision: https://reviews.llvm.org/D152652
This makes it clearer that the availability macro only pertains to
<filesystem>, and not to whether the platform has support for a file
system.
Differential Revision: https://reviews.llvm.org/D152172
We already have a clang-tidy check for making sure that `_LIBCPP_HIDE_FROM_ABI` is on free functions. This patch extends this to class members. The places where we don't check for `_LIBCPP_HIDE_FROM_ABI` are classes for which we have an instantiation in the library.
Reviewed By: ldionne, Mordante, #libc
Spies: jplehr, mikhail.ramalho, sstefan1, libcxx-commits, krytarowski, miyuki, smeenai
Differential Revision: https://reviews.llvm.org/D142332
This results in proper error messages instead of just an abort.
Reviewed By: ldionne, Mordante, #libc
Spies: #libc_vendors, smeenai, libcxx-commits
Differential Revision: https://reviews.llvm.org/D141222
Other macros that disable parts of the library are named `_LIBCPP_HAS_NO_WHATEVER`.
Reviewed By: ldionne, Mordante, #libc
Spies: libcxx-commits, smeenai
Differential Revision: https://reviews.llvm.org/D143163
_LIBCPP_HIDE_FROM_ABI (which is what _LIBCPP_INLINE_VISIBILITY is) uses
ABI tags to avoid ODR violations when linking together object files
compiled against different versions of libc++. However, pointer
authentication uses the mangled name of the function to sign the
function pointer in the vtable, which means that the ABI tag effectively
changes how the pointers are signed.
This leads to PAC failures when passing an object that holds one of these
pointers in its vtable across an ABI boundary: one side will sign the
pointer using one function mangling (with one ABI tag), and the other
side will authenticate the pointer expecting it to have a different
mangled name, which won't work.
To make sure this does not regress in the future, this patch also adds
a clang-query test to detect incorrect applications of _LIBCPP_HIDE_FROM_ABI.
Differential Revision: https://reviews.llvm.org/D140453
This commit reverts 5aaefa51 (and also partly 7f285f48e77 and b6d75682f9,
which were related to the original commit). As landed, 5aaefa51 had
unintended consequences on some downstream bots and didn't have proper
coverage upstream due to a few subtle things. Implementing this is
something we should do in libc++, however we'll first need to address
a few issues listed in https://reviews.llvm.org/D106124#3349710.
Differential Revision: https://reviews.llvm.org/D120683
libc++ has started splicing standard library headers into much more
fine-grained content for maintainability. It's very likely that outdated
and naive tooling (some of which is outside of LLVM's scope) will
suggest users include things such as <__ranges/access.h> instead of
<ranges>, and Hyrum's law suggests that users will eventually begin to
rely on this without the help of tooling. As such, this commit
intends to protect users from themselves, by making it a hard error for
anyone outside of the standard library to include libc++ detail headers.
Differential Revision: https://reviews.llvm.org/D106124
The NFC part of D116809. We still want to enforce this in CI,
but the mechanism for that is still to-be-determined.
Differential Revision: https://reviews.llvm.org/D116809
