242 Commits

Author SHA1 Message Date
Nikolas Klauser
ca697096aa
[libc++] Granularize <locale> (#146650) 2025-07-05 18:11:58 +02:00
David Spickett
d17a248fc6
[libcxx][test] Correct syntax of lit directives in some tests (#146886)
"XFAIL " does not do anything, you need to have the colon afterwards.
"XFAIL: ".

Found by searching for: (XFAIL|REQUIRES|UNSUPPORTED)[^:]
2025-07-04 12:48:16 +01:00
cor3ntin
381a649fb9
[Clang] Add warnings when mixing different charN_t types (#138708)
charN_t represent code units of different UTF encodings. Therefore the
values of 2 different charN_t objects do not represent the same
characters.

In order to avoid comparing apples and oranges, we add new warnings to
warn on:
  - Implicit conversions
  - Comparisons
  - Other cases involving arithmetic conversions

We only produce the warning if we cannot establish the comparison would
be safe through constant evaluation.

The new `-Wimplicit-unicode-conversion` warning is enabled by default.

Note that this PR intentionally doesn;t touches char/wchar_t, but it
would be worth considering also warning on extending the new warnings to
these types (in a follow up)

Additionally most arithmetic operations on charN_t don't really make
sense (ie what does it mean to addition code units), so we could add
warnings for that.

Fixes #138526
2025-05-15 18:16:05 +02:00
Martin Storsjö
205d399f30
[libcxx] [test] Clarify the condition for long double hex formatting (#135334)
This test currently hardcodes which environments have got 80 bit long
doubles on x86_64 with a suitable printf formatting; convert the
architecture check into a check specifically for 80 bit long doubles.

Not all x86_64 configurations do have 80 bit long doubles (e.g. 
Android doesn't), and i386 configurations can also have 80 bit long
doubles, compatible with this test.

Also clarify the exact reasons for why specific OSes such as FreeBSD are
skipped for these tests, even though they have 80 bit long doubles.
2025-04-25 09:53:30 +03:00
Mark de Wever
88e15b7815
[libc++] A quick-fix for the Apple CI. (#135202)
The Apple runners automatically pick up newer XCode versions breaking
the CI. This disables the test to get the CI green which allows us to
investigate the issue properly later on.
2025-04-11 17:05:30 +02:00
Nikolas Klauser
8fc2538f33
Reapply "[libc++] Optimize num_put integral functions" (#131613) (#133572)
This reverts commit d1156fcb56891fb1a426c3e8331a51d47f98a1b8.

This patch fixes the reported incorrect formatting changes and adds
tests for them. The performance should be unaffected, since there are no
significant changes required to fix the bugs.

Specifically, a `>` was changed to a `>=` to also add a `+` in the zero
case, and we're checking for zero now before printing the octal and
hexadecimal prefixes.

Closes #131710
2025-04-11 15:35:58 +02:00
Louis Dionne
b4f7a2ab57
[libc++] Bump OS version for macOS backdeployment CI jobs (#131883)
In 0547e573c555, I introduced backdeployment testing on macOS using
Github-provided builders. This was done by basically building libc++ on
a slightly older macOS (like macOS 13) and then running against the
system library on that machine. However, that created a dependency that
libc++ must keep working on macOS 13, which doesn't support the
latest-released Xcode.

This patch solves that problem by moving the deployment testing to a
newer version of macOS which supports the latest-released version of
Xcode.

Sadly, that also reduces the backdeployment coverage we have since we're
not actually testing on older OSes, but is necessary to satisfy the
documented libc++ support policy. In the future, we could improve the
situation by providing a Lit configuration that allows compiling (but
not running) all the tests, building the tests on a supported macOS, and
then shipping those tests on an older backdeployment target in order to
run them against the system library. Since that requires significant
engineering, this isn't done at this time.
2025-04-05 20:53:18 +02:00
Nikolas Klauser
457970d25d [libc++][NFC] Format std::num_put tests 2025-03-28 23:03:42 +01:00
Alexander Kornienko
d1156fcb56
Revert "[libc++] Optimize num_put integral functions" (#131613)
Reverts llvm/llvm-project#120859

This change breaks formatting of `0` with `std::showbase` + `std::hex`
or `std::oct`, as well as `+0` with `std::showpos`. I believe the new
behavior is violating the standard. See
https://github.com/llvm/llvm-project/pull/120859#issuecomment-2723970242
and later comments for details and explanation.
2025-03-18 02:05:51 +01:00
Nikolas Klauser
15edf8725a
[libc++] Optimize num_put integral functions (#120859)
```
-------------------------------------------------------
Benchmark                              old          new
-------------------------------------------------------
BM_num_put<bool>                   76.2 ns      32.0 ns
BM_num_put<long>                   76.9 ns      33.1 ns
BM_num_put<long long>              77.9 ns      34.2 ns
BM_num_put<unsigned long>          78.4 ns      33.1 ns
BM_num_put<unsigned long long>     78.0 ns      34.4 ns
BM_num_put<double>                  224 ns       228 ns
BM_num_put<long double>             239 ns       230 ns
BM_num_put<const void*>            68.7 ns      35.1 ns
```

Fixes #40109.
2025-03-05 14:18:49 +01:00
A. Jiang
ca0612c383
[libc++] Fix money_get::do_get with huge input (#126273)
`money_get::do_get` needs to be fixed to handle extremely huge input
(e.g. more than 100 digits).
1. `__double_or_nothing` needs to copy the contents of the stack buffer
on the initial allocation.
2. The `sscanf` call in `do_get` needs to scan the dynamic buffer if
dynamic allocation happens.
2025-03-03 07:13:38 +08:00
Martin Storsjö
f909b2229a
[libcxx] Provide locale conversions to tests through lit substitution (#105651)
There are 2 problems today that this PR resolves:

libcxx tests assume the thousands separator for fr_FR locale is x00A0 on
Windows. This currently fails when run on newer versions of Windows (it
seems to have been updated to the new correct value of 0x202F around
windows 11. The exact windows version where it changed doesn't seem to
be documented anywhere). Depending the OS version, you need different
values.

There are several ifdefs to determine the environment/platform-specific
locale conversion values and it leads to maintenance as things change
over time.

This PR includes the following changes:

- Provide the environment's locale conversion values through a
  substitution. The test can opt in by placing the substitution value in a
  define flag.
- Remove the platform ifdefs (the swapping of values between Windows,
  Linux, Apple, AIX).

This is accomplished through a lit feature action that fetches the
environment's locale conversions (lconv) for members like
'thousands_sep' that we need to provide. This should ensure that we
don't lose the effectiveness of the test itself.

In addition, as a result of the above, this PR:

- Fixes a handful of locale tests which unexpectedly fail on newer
  Windows versions.
- Resolves 3 XFAIL FIX-MEs.

Originally submitted in https://github.com/llvm/llvm-project/pull/86649.

Co-authored-by: Rodrigo Salazar <4rodrigosalazar@gmail.com>
2025-02-28 23:43:46 +02:00
Louis Dionne
aa6d3ff80d
[libc++] Re-enable the FreeBSD CI job (#127687)
Technical issues have apparently been resolved and the node should be
back online.

Closes #117780
2025-02-21 11:38:23 -05:00
Mark de Wever
de5ff8ad07
[libc++][test] Improves C++ Standard filtering. (#89499)
Adds a new lit directive to improve C++ Standard filtering. This is
based on the

[Discourse](https://discourse.llvm.org/t/rfc-improving-c-standard-filtering-in-the-lit-tests/78474)
discussion.
2025-01-25 13:08:00 +01:00
Vitaly Buka
31272e4f83
[libc++] Update locale grouping tests (#119463)
Fixes #119047
2024-12-16 12:50:59 -05:00
Jake Egan
e99755d41c
[libc++][test] Adjust expected hexfloat format (#95011)
The test expects a hex float format of `0x0p+0`, but AIX prints
`0x0.0p+0`. This change adjusts the test to accept both.
2024-09-16 16:21:41 -04:00
Louis Dionne
09e3a36058
[libc++][modules] Fix missing and incorrect includes (#108850)
This patch adds a large number of missing includes in the libc++ headers
and the test suite. Those were found as part of the effort to move
towards a mostly monolithic top-level std module.
2024-09-16 15:06:20 -04:00
Nikolas Klauser
5dfdac74ca
[libc++][NFC] Avoid opening namespace std in the tests (#94160)
This also adds a few FIXMEs where we use UB in the tests.
2024-08-01 10:57:21 +02:00
Martin Storsjö
ca69f515fe
[libcxx] [test] Detect the UCRT printf("%a") formatting bug (#99846)
This fixes testing with MinGW, if built without
__USE_MINGW_ANSI_STDIO=1.

On x86 MinGW, such a configuration fails printf tests with long doubles
due to mismatches between 80 and 64 bit long doubles - but on ARM,
there's no such issue, so building without __USE_MINGW_ANSI_STDIO=1 is
perfectly valid there.

Add another similar XFAIL to a libcxxabi test; this test isn't executed
in MSVC environments, so no XFAIL has been needed so far.
2024-07-26 20:29:14 +03:00
David Spickett
71a848632e
[libcxx][test] Update picolib xfails (#99631)
clang_modules_include.gen.py works now, and I added some background to
classic_table.pass.cpp.

Opened https://github.com/picolibc/picolibc/issues/778 to see if that
one is possible to fix.
2024-07-24 10:45:00 +01:00
Martin Storsjö
ec966f699d
[libcxx] [test] Make indentation more consistent in thousands_sep. NFC. (#99844)
This was made inconsistent recently in
f114eddb1923289b696f1b0980cc22c4dbaafa22.
2024-07-22 19:31:47 +03:00
Louis Dionne
7918e624ad
[libc++] Test suite portability improvements (#98527)
This patch contains a number of small portability improvements for the
test suite, making it easier to run the test suite with other standard
library implementations.

- Guard checks for _LIBCPP_HARDENING_MODE to avoid -Wundef
- Avoid defining _LIBCPP_HARDENING_MODE even when no hardening mode is
  specified -- we should use the default mode of the library in that case.
- Add missing includes and qualify a few function calls.
- Avoid opening namespace std to forward declare stdlib containers. The
  test suite should represent user code, and user code isn't allowed to do
  that.
2024-07-12 10:17:00 -04:00
Louis Dionne
3497500946
[libc++] Clean up and update deployment target features (#96312)
This patch removes many annotations that are not relevant anymore since
we don't support or test back-deploying to macOS < 10.13. It also cleans
up raw usage of target triples to identify versions of dylibs shipped on
prior versions of macOS, and uses the target-agnostic Lit features
instead. Finally, it reorders both the Lit backdeployment features and
the corresponding availability macros in the library in a way that makes
more sense, and reformulates the Lit backdeployment features in terms of
when a version of LLVM was introduced instead of encoding the system
versions on which it hasn't been introduced yet. Although one can be
derived from the other, encoding the negative form is extremely
error-prone.

Fixes #80901
2024-06-28 10:40:35 -05:00
Louis Dionne
db8c7e004a
[libc++] Fix deployment target Lit features (#94791)
We were not making any distinction between e.g. the "Apple-flavored"
libc++ built from trunk and the system-provided standard library on
Apple platforms. For example, any test that would be XFAILed on a
back-deployment target would unexpectedly pass when run on that
deployment target against the tip of trunk Apple-flavored libc++. In
reality, that test would be expected to pass because we're running
against the latest libc++, even if it is Apple-flavored.

To solve this issue, we introduce a new feature that describes whether
the Standard Library in use is the one provided by the system by
default, and that notion is different from the underlying standard
library flavor. We also refactor the existing Lit features to make a
distinction between availability markup and the library we're running
against at runtime, which otherwise limit the flexibility of what we can
express in the test suite. Finally, we refactor some of the
back-deployment versions that were incorrect (such as thinking that LLVM
10 was introduced in macOS 11, when in reality macOS 11 was synced with
LLVM 11).

Fixes #82107
2024-06-21 10:31:22 -04:00
David Tenty
9afb09e674
[libcxx][test][AIX] address more platform differences in locale tests (#94826)
This is a follow on to https://github.com/llvm/llvm-project/pull/92312,
where we address some more locale platform differences. These are:

- for locale fr_FR AIX libc expects `U202F` as `LC_MONETARY`
`thousands_sep`
- for locale zh_CN AIX libc `LC_MONETARY` has `n_sign_posn == 1`,
indicating the `negative_sign` should come before the `currency_symbol`
string
2024-06-14 11:13:54 -04:00
A. Jiang
ac4cca3cb1
[libc++] Fix regression about parsing leading decimal points (#93989)
PR #77948 mistakenly rejected floating-point representation with a
leading decimal point, e.g. ".5".

This PR fixes the regression mentioned in
https://github.com/llvm/llvm-project/pull/77948#issuecomment-2141740346.
2024-06-03 11:28:58 -04:00
David Tenty
f114eddb19
[libcxx][test][AIX] Fix the thousands_sep expectation for fr_FR locales (#92312)
Similar to some other platforms, AIX uses ' ' for non-wide characters
and U202F for wide characters, so this change opts into those paths for
AIX as well.
2024-05-27 15:39:05 -04:00
A. Jiang
3e15c97fa3
[libc++] LWG2381: Inconsistency in parsing floating point numbers (#77948)
This PR implements [LWG2381](https://cplusplus.github.io/LWG/issue2381)
by rejecting `'i'`, `'I'`, `'n'`, `'N'` in FP parsing, as inf and NaN
are intendedly rejected by that LWG issue.

The source character array used for parsing is
`"0123456789abcdefABCDEFxX+-pPiInN"`, whose first 26 or 28 characters
are used for parsing integers or floating-point values respectively.
Previously, libc++ used 32 characters, including `'i'`, `'I'`, `'n'`,
`'N'`, for FP parsing, which was inconsistent with LWG2381. This PR also
replaces magic numbers 26 and 28 (formerly 32) with named constants.

Drive-by change: when the first character (possibly after the leading
`'+'` or `'-'`) is not a decimal digit but an acceptable character
(e.g., `'p'` or `'e'`), the character is not accumulated now (per Stage
2 in [facet.num.get.virtuals]/3).

#65168 may be rendered invalid, see
https://github.com/llvm/llvm-project/pull/65168#issuecomment-1868533342.

Apple back-deployment targets remain broken, likely due to dylib. XFAIL
is marked in related tests.

---------

Co-authored-by: Mark de Wever <koraq@xs4all.nl>
2024-05-21 19:05:51 +02:00
Xing Xue
7eeccc1430
[libcxx][test] Fix numpunct grouping tests on AIX (#91781)
The `grouping` string for locale `en_US.UTF-8` and `fr_FR.UTF-8` on AIX
is `3`. This is different from Linux's `3;3` but is the same as Windows.
This patch removes `XFAIL: LIBCXX-AIX-FIXME` and changes to use the
`WIN32` code path.
2024-05-13 06:30:25 -04:00
Xing Xue
3438d8ac1b
[libcxx] [test] Fix the locale ctype widen tests on AIX (#91744)
The C locale on AIX uses `ISO-8859-1`, where `0xFB` is a valid
character. Widening char(-5) succeeds and produces L'\u00fb' the same as
on macOS, FreeBSD, and Windows. This patch removes `XFAIL:
LIBCXX-AIX-FIXME` and uses the macOS, FreeBSD, and WIN32 code path for
AIX.
2024-05-13 06:29:50 -04:00
Hristo Hristov
a834436099
[libc++] P2872R3: Remove `wstring_convert` From C++26 (#87100)
Implements: https://wg21.link/P2872R3
2024-04-05 22:04:07 +03:00
Louis Dionne
d1f585056f
[libc++] Fix tests on musl (#85085) (#86934)
One or two of the tests need slight tweaks to make them pass when
building with musl.

This patch is a re-application of b61fb18 which was reverted in 0847c90
because it broke the build.

rdar://118885724

Co-authored-by: Alastair Houghton <ahoughton@apple.com>
2024-04-03 06:07:46 -04:00
Mark de Wever
0847c903c8 Revert "[libc++] Fix tests on musl (#85085)"
This reverts commit b61fb18456ecd798b2fc340367018ab3109ebfae.

This commit landed with build failures in the pre-commit CI
https://buildkite.com/llvm-project/libcxx-ci/builds/34153
2024-03-16 20:22:49 +01:00
Alastair Houghton
b61fb18456
[libc++] Fix tests on musl (#85085)
One or two of the tests need slight tweaks to make them pass when
building with musl.

rdar://118885724
2024-03-13 14:48:13 -04:00
Abhina Sree
1197fcabc4
[libcxx][test] Change UNSUPPORTED to XFAIL for target-related failures (#81513)
This is a followup from this discussion
https://github.com/llvm/llvm-project/pull/80735#discussion_r1486586017
to mark targets that were initially marked as UNSUPPORTED with an XFAIL
instead.
2024-02-23 08:01:56 -05:00
Louis Dionne
785e0945ce
[libc++] Fix incomplete user-defined ctype specialization in test (#74630)
The specialization was non-conforming because it was missing a bunch of
member functions. Those were missing probably just as an oversight
coupled with a bit of laziness -- the rule that user-defined
specializations need to match the base template is usually OK to take
with a grain of salt, but not when the code is supposed to be portable,
which our test suite aims to be.

Fixes #74214
2023-12-13 10:27:28 -05:00
Michael Platings
be811d1617 [libc++] Run picolibc tests with qemu
This patch actually runs the tests for picolibc behind an emulator,
removing a few workarounds and increasing coverage.

Differential Revision: https://reviews.llvm.org/D155521
2023-11-29 17:21:08 -05:00
Dimitrij Mijoski
390840fbdf
[libc++] Fix UTF-8 decoding in codecvts (#68442)
This patch fixes one case where the decoding member function `in()` was
returning `partial` instead of `error`. Additionally, it adds large
testsuite that tests all `codecvt` facets that were added in C++11 and
in C++20. The testsuite covers this bug.

Fixes #60177.
2023-11-27 18:31:03 +01:00
Mark de Wever
233e7c5de2
[libc++] Removes codecvt. (#72496)
Implements:
- P2871R3 Remove Deprecated Unicode Conversion Facets from C++26
2023-11-24 17:34:30 +01:00
Louis Dionne
026776fb60
[libc++] Refactor the creation of the global and classic locales (#72581)
The creation of the global and the classic locales was pretty twisty.
This patch refactors how this is done to reduce the amount of
indirections and prepare the terrain for a future where GCC implements
the no_destroy attribute.
2023-11-23 10:28:57 -05:00
Ryan Prichard
bce3b50593
[libc++][Android] Mark tests XFAIL/UNSUPPORTED (#69271)
Mark tests as necessary to accommodate Android L (5.0 / API 21) and up.

Add three Android lit features:
 - android
 - android-device-api=(21,22,23,...)
 - LIBCXX-ANDROID-FIXME (for failures that need follow-up work)

Enable an AIX workaround in filesystem_test_helper.h for the broken
chmod on older Android devices.

Mark failing test with XFAIL or UNSUPPORTED:
 - Mark modules tests as UNSUPPORTED, matching other configurations.
 - Mark a gdb test as UNSUPPORTED.
 - XFAIL tests for old devices that lack an API (fmemopen).
- XFAIL various FS tests (because SELinux blocks FIFO and hard linking,
because fchmodat is broken on old devices).
- XFAIL various locale tests (because Bionic has limited locale
support). (Also XFAIL an re.traits test.)
- XFAIL some print.fun tests because the error exception has no system
error string.
- Mark std::{cin,wcin} tests UNSUPPORTED because they hang with
adb_run.py on old devices.
 - Mark a few tests UNSUPPORTED because they allocate too much memory.
 - notify_one.pass.cpp is flaky on Android.
- XFAIL libc++abi demangler test because of Android's special long
double on x86[-64].

N.B. The `__ANDROID_API__` macro specifies a minimum required API level
at build-time, whereas the android-device-api lit feature is the
detected API level of the device at run-time. The android-device-api
value will be >= `__ANDROID_API__`.

This commit was split out from https://reviews.llvm.org/D139147.

Fixes: https://github.com/llvm/llvm-project/issues/69270
2023-10-19 17:27:01 -07:00
Louis Dionne
3e24a77a86 [libc++] Use the default initializer for char_type in std::num_get::do_get
This is to fix an error that occurs when the char type is a class type.
Thanks to Yichen Yan for the patch.

Differential Revision: https://reviews.llvm.org/D100005
2023-09-11 14:16:47 -04:00
Alexander Richardson
bf1bcb68fc [libc++] Use intptr_t instead of ptrdiff_t for messages_base::catalog
On GLibc, FreeBSD and macOS systems nl_catd is a pointer type, and
round-tripping this in a variable of ptrdiff_t is not portable.
In fact such a round-trip yields a non-dereferenceable pointer on
CHERI-enabled architectures such as Arm Morello. There pointers (and
therefore intptr_t) are twice the size of ptrdiff_t, which means casting
to ptrdiff_t strips the high (metadata) bits (as well as a hidden pointer
validity bit).

Since catalog is now guaranteed to be the same size or larger than nl_catd,
we can store all return values safely and the shifting workaround from
commit 0c68ed006d4f38c3cdcab6a565aa3e208015895f should not be needed
anymore (this is also not portable to CHERI systems on since shifting a
valid pointer right will create a massively out-of-bounds pointer that
may not be representable).

This can be fixed by using intptr_t which should be the same type as
ptrdiff_t on all currently supported architectures.

See also: https://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2028

Differential Revision: https://reviews.llvm.org/D134420

Co-authored-by: Louis Dionne <ldionne.2@gmail.com>
2023-09-08 09:15:57 -04:00
Jake Egan
643b7bcdb4 [libc++] Fix simple cases of locale name construction
When using the following constructors:

```
locale(const locale& other, const char* std_name, category cat);
locale(const locale& other, const string& std_name, category cat);
locale(const locale& other, const locale& one, category cats);
```
The new locale name is always "*". Locale names formed from parts of two named locales (that is, C++ locales having names) are supposed to have names in turn (see C++20 subclause 28.3.1.1 [locale.general] paragraph 8). This patch fixes the name construction for cases when either of locales are unnamed, when the category is locale::none, and when the two locale names are the same.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D119441
2023-07-08 22:02:56 -04:00
Louis Dionne
60a6a0d17a [libc++] Add missing includes
Those were found while trying to enable configurations like no-threads
and no-localization with Clang modules enabled.

Differential Revision: https://reviews.llvm.org/D153977
2023-07-03 09:40:09 -04:00
Louis Dionne
66a562d22e [libc++] Roll up fstream support into filesystem support
LIBCXX_ENABLE_FILESYSTEM should represent whether the platform has
support for a filesystem, not just whether we support <filesystem>.
This patch slightly generalizes the setting to also encompass whether
we provide <fstream>, since that only makes sense when a filesystem is
supported.

Differential Revision: https://reviews.llvm.org/D152168
2023-06-07 08:04:58 -07:00
Tobias Hieta
7bfaa0f09d
[NFC][Py Reformat] Reformat python files in libcxx/libcxxabi
This is an ongoing series of commits that are reformatting our
Python code.

Reformatting is done with `black`.

If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.

If you run into any problems, post to discourse about it and
we will try to help.

RFC Thread below:

https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style

Reviewed By: #libc, kwk, Mordante

Differential Revision: https://reviews.llvm.org/D150763
2023-05-25 11:15:34 +02:00
Mark de Wever
0bc0edb847 [libc++] Implements isblank.
This omission seems to be there for a long time, it's in the initial
libc++ import. This was discovered while working on the std modules.

Reviewed By: #libc, philnik

Differential Revision: https://reviews.llvm.org/D147850
2023-04-09 13:11:59 +02:00
Louis Dionne
ed61d6a466 [libc++] Use the stdlib=<LIB> Lit feature instead of use_system_cxx_lib
The use_system_cxx_lib Lit feature was only used for back-deployment
testing. However, one immense hole in that setup was that we didn't
have a proper way to test Apple's own libc++ outside of back-deployment,
which was embodied by the fact that we needed to define _LIBCPP_DISABLE_AVAILABILITY
when testing (see change in libcxx/utils/libcxx/test/params.py).

This led to the apple-system testing configuration not checking for
availability markup, which is obviously quite bad since the library
we ship actually has availability markup.

Using stdlib=<VENDOR>-libc++ instead to encode back-deployment restrictions
on tests is simpler and it makes it possible to naturally support tests
such as availability markup checking even in the tip-of-trunk Apple-libc++
configuration.

Differential Revision: https://reviews.llvm.org/D146366
2023-03-30 06:57:56 -04:00
Louis Dionne
f0fc8c4878 [libc++] Use named Lit features to flag back-deployment XFAILs
Instead of writing something like `XFAIL: use_system_cxx_lib && target=...`
to XFAIL back-deployment tests, introduce named Lit features like
`availability-shared_mutex-missing` to represent those. This makes the
XFAIL annotations leaner, and solves the problem of XFAIL comments
potentially getting out of sync. This would also make it easier for
another vendor to add their own annotations to the test suite by simply
changing how the feature is defined for their OS releases, instead
of having to modify hundreds of tests to add repetitive annotations.

This doesn't touch *all* annotations -- only annotations that were widely
duplicated are given named features (e.g. when filesystem or shared_mutex
were introduced). I still think it probably doesn't make sense to have a
named feature for every single fix we make to the dylib.

This is in essence a revert of 2659663, but since then the test suite
has changed significantly. Back when I did 2659663, the configuration
files we have for the test suite right now were being bootstrapped and
it wasn't clear how to provide these features for back-deployment in
that context. Since then, we have a streamlined way of defining these
features in `features.py` and that doesn't impact the ability for a
configuration file to stay minimal.

The original motivation for this change was that I am about to propose
a change that would touch essentially all XFAIL annotations for back-deployment
in the test suite, and this greatly reduces the number of lines changed
by that upcoming change, in addition to making the test suite generally
better.

Differential Revision: https://reviews.llvm.org/D146359
2023-03-27 12:44:26 -04:00