42 Commits

Author SHA1 Message Date
Louis Dionne
d145f716ae
[libc++] Bump Xcode support (#148651)
Libc++'s policy is to support only the latest released Xcode, which is
Xcode 16.x. We did update our CI jobs to Xcode 16.x, but we forgot to
update the documentation, which still mentioned Xcode 15. This patch
updates the documentation and cleans up outdated mentions of
apple-clang-15 in the test suite.
2025-07-15 10:45:37 -04:00
Nikolas Klauser
fda3fbee6f
Revert "[libc++][hardening] Introduce a dylib function to log hardening errors." (#148787)
Reverts llvm/llvm-project#148266

I'm reverting this temporarily, since the release branch is today and
this is ABI sensitive. Let's wait until after the branch so that we have
plenty time to discuss the patch.
2025-07-15 12:12:41 +02:00
Konstantin Varlamov
49d2b5f1cd
[libc++][hardening] Introduce a dylib function to log hardening errors. (#148266)
Unlike `verbose_abort`, this function merely logs the error but does not
terminate execution. It is intended to make it possible to implement the
`observe` semantic for Hardening.
2025-07-14 17:04:33 -07:00
Nikolas Klauser
f2fede6095
[libc++] Document our ABI guarantees and what ABI flags exist to modify these guarantees (#132615) 2025-06-10 12:59:08 +02:00
Nikolas Klauser
705eedd47d
[libc++] Remove availability annotations which can't fire anymore (#140049)
According to https://developer.apple.com/support/xcode/ the removed
annotations can't fire anymore, since the targets they would fire for
aren't supported anymore.
2025-06-02 13:13:57 -04:00
Jessica Clarke
35757d67ba
Revert "[libc++] Re-enable std::pair trivial copy constructor for FreeBSD >= 14" (#142204)
The ABI bump to adopt the conforming ABI v1 std::pair implementation did
not end up happening for FreeBSD 14, and instead this diff was reverted
downstream in FreeBSD[1]. Align the upstream ABI config with FreeBSD's
actual ABI.

[1] ce4f1f49e036 ("Revert commit 6255157d24e2 from llvm-project (by
Dimitry Andric):")

This reverts commit 6255157d24e27c604bda8fe8ce26e896f54785c0.
2025-05-31 08:07:15 +01:00
Louis Dionne
25fc52e655
[libc++] Re-introduce _LIBCPP_DISABLE_AVAILABILITY (#134158)
The `_LIBCPP_DISABLE_AVAILABILITY` macro was removed in afae1a5f32bb as an
intended no-op. It turns out that some projects are making use of that
macro to work around a Clang bug with availability annotations that
still exists: https://github.com/llvm/llvm-project/issues/134151.

Since that Clang bug still hasn't been fixed, I feel that we must sill
honor that unfortunate macro until we've figured out how to get rid of
it without breaking code.
2025-05-05 14:19:13 -07:00
Nikolas Klauser
9fdb4f3537
[libc++] Make bad_function_call::what() existence a matter of availability instead of ABI (#127697)
We're currently adding `bad_function_call::what()` behind an ABI flag,
even though adding it is not an ABI break and can be handled through
availability.
2025-04-25 10:45:46 +02:00
Louis Dionne
a97f73405f
[libc++] Fix deployment targets that were incorrectly bumped (#134278)
When I introduced the various `_LIBCPP_INTRODUCED_IN_LLVM_XY_ATTRIBUTE`
macros in 182f5e9b2f03, I tried to correlate them to the right OS
versions, but it seems that I made a few mistakes. This wasn't caught in
the CI because we don't test back-deployment that far.

rdar://148405946
2025-04-04 14:56:26 -04:00
Louis Dionne
4090910a69
[libc++] Guard additional headers with _LIBCPP_HAS_LOCALIZATION (#131921)
There were some remaining headers that were not guarded with
_LIBCPP_HAS_LOCALIZATION, leading to errors when trying to use modules
on platforms that don't support localization (since all the headers get
pulled in when building the 'std' module). This patch brings these
headers in line with what we do for every other header that depends on
localization.

This patch also requires including <picolibc.h> from
<__configuration/platform.h> in order to define _NEWLIB_VERSION. In the
long term, we should use a better approach for doing that, such as
defining a macro in the __config_site header.
2025-04-04 11:48:46 -04:00
Mark de Wever
82c078c54d
[libc++] Remove official Clang 18 support. (#130142)
Since Clang 20 has been release we no longer support Clang 18 per our
policy.

Note the Clang 18 workarounds will be removed in a follow-up patch.
2025-03-27 18:00:46 +01:00
Nikolas Klauser
17d0569538
[libc++] Instantiate hash function externally (#127040)
This has multiple benefits:
- There is a single instance of our hash function, reducing object file
size
- The hash implementation isn't instantiated in every TU anymore,
reducing compile times
- Behind an ABI configuration macro it would be possible to salt the
hash
2025-03-27 13:19:59 +01:00
Louis Dionne
2c8b124851
[libc++] Guard include of <features.h> with __has_include (#127691)
Some configurations define __AMDGPU__ or __NVPTX__ on platforms that
don't provide <features.h>, such as CUDA on Mac.
2025-02-19 08:21:56 -05:00
Louis Dionne
cffc1ac349
[libc++] Avoid including <features.h> on arbitrary platforms (#125587)
This partially reverts commit 5f2389d4. That commit started checking
whether <features.h> was a valid include unconditionally, however codebases
are free to have such a header on their search path, which breaks compilation.
LLVM libc now provides a more standard way of getting configuration macros
like __LLVM_LIBC__.

After this patch, we only include <features.h> when we're on Linux or
when we're compiling for GPUs.
2025-02-15 10:54:00 +01:00
Nikolas Klauser
956cfa69b1
[libc++] Refactor num_get optimization to not be ABI breaking (#121690)
```
----------------------------------------------------
Benchmark                             old        new
----------------------------------------------------
BM_num_get<bool>                  81.8 ns    79.6 ns
BM_num_get<long>                  80.2 ns    75.4 ns
BM_num_get<long long>             81.5 ns    76.4 ns
BM_num_get<unsigned short>        82.5 ns    78.4 ns
BM_num_get<unsigned int>          82.8 ns    78.6 ns
BM_num_get<unsigned long>         81.2 ns    78.1 ns
BM_num_get<unsigned long long>    83.6 ns    76.7 ns
BM_num_get<float>                  119 ns     120 ns
BM_num_get<double>                 113 ns     109 ns
BM_num_get<long double>            115 ns     119 ns
BM_num_get<void*>                  147 ns     139 ns
```
2025-01-30 10:45:47 +01:00
Nikolas Klauser
7f845cba2c
[libc++] Update the CI to Clang-20 and drop Clang-17 support (#117429) 2025-01-28 12:35:33 +01:00
Nikolas Klauser
04cc492ec3 [libc++][NFC] Remove unused macros from <__configuration/availability.h> 2024-11-30 13:18:33 +01:00
Louis Dionne
afae1a5f32
[libc++] Remove _LIBCPP_DISABLE_AVAILABILITY macro (#112952)
This was slated for removal years ago, so now's a good time to remove it.
2024-11-23 20:02:15 -05:00
Louis Dionne
427a5cf105
[libc++] Add support for bounded iterators in std::array (#110729)
This patch introduces a new kind of bounded iterator that knows the size
of its valid range at compile-time, as in std::array. This allows computing
the end of the range from the start of the range and the size, which requires
storing only the start of the range in the iterator instead of both the start
and the size (or start and end). The iterator wrapper is otherwise identical
in design to the existing __bounded_iter.

Since this requires changing the type of the iterators returned by
std::array, this new bounded iterator is controlled by an ABI flag.

As a drive-by, centralize the tests for std::array::operator[] and add
missing tests for OOB operator[] on non-empty arrays.

Fixes #70864
2024-11-07 09:23:21 -05:00
Nikolas Klauser
c6f3b7bcd0
[libc++] Refactor the configuration macros to being always defined (#112094)
This is a follow-up to #89178. This updates the `<__config_site>`
macros.
2024-11-06 10:39:19 +01:00
Louis Dionne
dfe737f231
[libc++] Apply post-commit review comments for unique_ptr<T[]> hardening (#111704) 2024-11-04 10:45:12 -05:00
Michael Jones
6c4267fb17
[libcxx][libc] Hand in Hand PoC with from_chars (#91651)
Implements std::from_chars for float and double.

The implementation uses LLVM-libc to do the real parsing. Since this is
the first time libc++
uses LLVM-libc there is a bit of additional infrastructure code. The
patch is based on the
[RFC] Project Hand In Hand (LLVM-libc/libc++ code sharing)

https://discourse.llvm.org/t/rfc-project-hand-in-hand-llvm-libc-libc-code-sharing/77701
2024-10-21 15:04:06 -07:00
Nikolas Klauser
ba87515fea
[libc++][RFC] Always define internal feature test macros (#89178)
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>`.
2024-10-12 09:49:52 +02:00
Louis Dionne
18df9d23ea [libc++] Add an ABI setting to harden unique_ptr<T[]>::operator[] (#91798)
This allows catching OOB accesses inside `unique_ptr<T[]>` when the size
of the allocation is known. The size of the allocation can be known when
the unique_ptr has been created with make_unique & friends or when the
type necessitates an array cookie before the allocation.

This is a re-aplpication of 45a09d181 which had been reverted in
f11abac6 due to unrelated CI failures.
2024-09-30 08:32:35 -04:00
Chris B
f11abac652
Revert "[libc++][modules] Rewrite the modulemap to have fewer top-level modules (#107638)" (#110384)
This reverts 3 commits:
45a09d1811d5d6597385ef02ecf2d4b7320c37c5
24bc3244d4e221f4e6740f45e2bf15a1441a3076
bc6bd3bc1e99c7ec9e22dff23b4f4373fa02cae3

The GitHub pre-merge CI has been broken since this PR went in. This
change reverts it to see if I can get the pre-merge CI working again.
2024-09-28 21:47:09 -05:00
Louis Dionne
48dc4d39c7
[libc++][Apple] Add missing availabilty mappings for Apple platforms (#110289) 2024-09-27 16:05:01 -04:00
Louis Dionne
4036413320
[libc++] Add availability mapping for LLVM 18 on Apple platforms (#110158) 2024-09-27 08:52:28 -04:00
Louis Dionne
45a09d1811
[libc++] Add an ABI setting to harden unique_ptr<T[]>::operator[] (#91798)
This allows catching OOB accesses inside `unique_ptr<T[]>` when the size
of the allocation is known. The size of the allocation can be known when
the unique_ptr has been created with make_unique & friends or when the
type necessitates an array cookie before the allocation.
2024-09-27 08:49:22 -04:00
Nikolas Klauser
27c83382d8
[libc++] Replace __compressed_pair with [[no_unique_address]] (#76756)
This significantly simplifies the code, improves compile times and
improves the object layout of types using `__compressed_pair` in the
unstable ABI. The only downside is that this is extremely ABI sensitive
and pedantically breaks the ABI for empty final types, since the address
of the subobject may change. The ABI of the whole object should not be
affected.

Fixes #91266
Fixes #93069
2024-09-16 11:08:57 +02:00
Joseph Huber
5f2389d49f
[libc++] Do not redeclare lgamma_r when targeting the LLVM C library (#102036)
We use lgamma_r for the random normal distribution support. In this
code we redeclare it, which causes issues with the LLVM C library as
this function is marked noexcept in LLVM libc. This patch ensures that
we don't redeclare that function when targeting LLVM libc.
2024-08-27 17:46:03 -04:00
Louis Dionne
4f79ef4eff
[libc++] Revert "Make std::pair trivially copyable if its members are (#89652)" (#100184)
This reverts commit f9dd885cb6e6b. We're not certain yet whether the
patch has issues, so we are reverting until we've had time to
investigate.
2024-07-23 21:14:05 -04:00
David Benjamin
bcf9fb9802
[libc++][hardening] Use bounded iterators in std::vector and std::string (#78929)
~~NB: This PR depends on #78876. Ignore the first commit when reviewing,
and don't merge it until #78876 is resolved. When/if #78876 lands, I'll
clean this up.~~

This partially restores parity with the old, since removed debug build.
We now can re-enable a bunch of the disabled tests. Some things of note:

- `bounded_iter`'s converting constructor has never worked. It needs a
friend declaration to access the other `bound_iter` instantiation's
private fields.

- The old debug iterators also checked that callers did not try to
compare iterators from different objects. `bounded_iter` does not
currently do this, so I've left those disabled. However, I think we
probably should add those. See
https://github.com/llvm/llvm-project/issues/78771#issuecomment-1902999181

- The `std::vector` iterators are bounded up to capacity, not size. This
makes for a weaker safety check. This is because the STL promises not to
invalidate iterators when appending up to the capacity. Since we cannot
retroactively update all the iterators on `push_back()`, I've instead
sized it to the capacity. This is not as good, but at least will stop
the iterator from going off the end of the buffer.

There was also no test for this, so I've added one in the `std`
directory.

- `std::string` has two ambiguities to deal with. First, I opted not to
size it against the capacity. https://eel.is/c++draft/string.require#4
says iterators are invalidated on an non-const operation. Second,
whether the iterator can reach the NUL terminator. The previous debug
tests and the special-case in https://eel.is/c++draft/string.access#2
suggest no. If either of these causes widespread problems, I figure we
can revisit.

- `resize_and_overwrite.pass.cpp` assumed `std::string`'s iterator
supported `s.begin().base()`, but I see no promise of this in the
standard. GCC also doesn't support this. I fixed the test to use
`std::to_address`.

- `alignof.compile.pass.cpp`'s pointer isn't enough of a real pointer.
(It needs to satisfy `NullablePointer`, `LegacyRandomAccessIterator`,
and `LegacyContiguousIterator`.) `__bounded_iter` seems to instantiate
enough to notice. I've added a few more bits to satisfy it.

Fixes #78805
2024-07-22 22:44:25 -07:00
Nikolas Klauser
f9dd885cb6
[libc++] Make std::pair trivially copyable if its members are (#89652)
This makes `std::pair` trivially copyable if its members are and we have
a way to do so. We need either C++20 with requires clauses or support
for `__attribute__((enable_if))`. Only Clang has support for this
attribute, so it's effectively clang or C++20.

Co-authored-by: Christopher Di Bella <cjdb@google.com>
2024-07-20 19:59:06 +02:00
Xing Xue
194f98c221
[libc++] basic_ios<wchar_t> cannot store fill character WCHAR_MAX (#89305)
`libcxx std::basic_ios` uses `WEOF` to indicate the `fill` value is
uninitialized. On some platforms (e.g AIX and zOS in 64-bit mode)
`wchar_t` is 4 bytes `unsigned` and `wint_t` is also 4 bytes which means
`WEOF` cannot be distinguished from `WCHAR_MAX` by
`std::char_traits<wchar_t>::eq_int_type()`, meaning this valid character
value cannot be stored on affected platforms (as the implementation
triggers reinitialization to `widen(’ ’)`).

This patch introduces a new helper class `_FillHelper` uses a boolean
variable to indicate whether the fill character has been initialized,
which is used by default in libcxx ABI version 2. The patch does not
affect ABI version 1 except for targets AIX in 32- and 64-bit and z/OS
in 64-bit (so that the layout of the implementation is compatible with
the current IBM system provided libc++)

This is a continuation of Phabricator patch
[D124555](https://reviews.llvm.org/D124555). This patch uses a modified
version of the [approach](https://reviews.llvm.org/D124555#3566746)
suggested by @ldionne .

---------

Co-authored-by: Louis Dionne <ldionne.2@gmail.com>
Co-authored-by: David Tenty <daltenty.dev@gmail.com>
2024-07-17 14:47:13 -04:00
Nikolas Klauser
9e9404387d
[libc++] Remove annotations for GCC 13 and update the documentation (#97744)
GCC 14 has been released a while ago. We've updated the CI to use GCC 14
now. This removes any old annotations in the tests and updates the
documentation to reflect the updated version requirements.
2024-07-06 16:52:45 +02:00
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
Louis Dionne
e2c2ffbe7a
[libc++][NFC] Run clang-format on libcxx/include again (#95874)
As time went by, a few files have become mis-formatted w.r.t.
clang-format. This was made worse by the fact that formatting was not
being enforced in extensionless headers. This commit simply brings all
of libcxx/include in-line with clang-format again.

We might have to do this from time to time as we update our clang-format
version, but frankly this is really low effort now that we've formatted
everything once.
2024-06-18 09:13:45 -04:00
Konstantin Varlamov
86070a84c4
[libc++][hardening] Finish documenting hardening. (#92021) 2024-06-06 16:35:33 -07:00
Nikolas Klauser
5d31360d71
[libc++] Remove the inline namespace for std::filesystem in ABIv2 (#92971) 2024-06-01 08:37:49 +02:00
Louis Dionne
04f01a2b9c
[libc++] Make the __availability header a sub-header of __config (#93083)
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>.
2024-05-28 18:29:11 -07:00
Louis Dionne
23e1ed65c2
[libc++] Split up ABI and platform configuration to their own headers (#90863)
This is a first step towards splitting up the <__config> header. The
<__config> header is large and rather disorganized at this point,
leading to confusion and subtle mistakes. For example, we never noticed
that the string layout used on arm64 was only enabled for the Clang
compiler, as the setting being in the compiler == clang block was
probably never intentional.

The danger of splitting up the <__config> header is to implicitly use
undefined macros that should have been defined prior to their usage,
however this can be remediated with -Wundef and we've started moving
towards -Wundef enforceable macros.
2024-05-28 07:22:06 -04:00