I had a look at the changes since the last release and updated the
release notes with interesting changes.
It seems this time the release notes were already rather up to date :-)
If there are more interesting changes, please let me know and I'll
update the patch. I'd like to commit these changes latest next weekend
so they land before branching the 14.0 release.
I've added most active libc++ contributors. If I forgot anybody please add them.
Reviewed By: Quuxplusone, ldionne, philnik, #libc
Differential Revision: https://reviews.llvm.org/D117948
Since basic_string::reserve(n) is instantiated in the shared library but also
available to the compiler for inlining, its definition should not depend on
things like the Standard mode in use. Indeed, that flag may not match between
how the shared library is compiled and how users are compiling their own code,
resulting in ODR violations.
However, note that we retain the behavior of basic_string::reserve() to
shrink the string for backwards compatibility reasons. While it would
technically be conforming to not shrink, we believe user expectation is
for it to shrink, and so existing code might have been written based on
that assumption. We prefer to not break such code, even though that makes
basic_string::reserve() and basic_string::reserve(0) not equivalent anymore.
Fixes llvm-project#53170
Differential Revision: https://reviews.llvm.org/D117332
This adjust the version macro and sets it as completed. All parts of the paper
have been implemented, except for the parts replaced by later papers and
LWG-issues.
Adjusted the synopsis to match the synopsis in the Standard. Not yet
implemented parts of P2216 and P2418 still use the P0645 wording.
Completes:
- P0645 Text Formatting
Depends on D115991
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D115999
It was not in P0355R7, nor has it ever been so in a working draft.
Drive-by:
* tests should test something: fix loop bounds so initial value is not >= final value
* calender type streaming tests are useless - let's remove them
* don't declare printf, especially if you don't intend to use it
Differential Revision: https://reviews.llvm.org/D117638
This essentially reverts e02ed1c255 and puts in a new fix, which makes `path::iterator`
a true C++20 `bidirectional_iterator`, but downgrades it to an `input_iterator` in C++17.
Fixes#37852.
Differential Revision: https://reviews.llvm.org/D116489
On Apple platforms, arc4random is faster than /dev/urandom, and it is
the recommended user-space RNG according to Apple's own OS folks.
This commit adds an ABI switch to guard ABI-break-protections in
std::random_device, and starts using arc4random instead of /dev/urandom
to implement std::random_device on Apple platforms.
Note that previously, `std::random_device` would allow passing a custom
token to its constructor, and that token would be interpreted as the name
of a file to read entropy from. This was implementation-defined and
undocumented. After this change, Apple platforms will be using arc4random()
instead, and any custom token passed to the constructor will be ignored.
This behavioral change will also impact other platforms that use the
arc4random() implementation, such as OpenBSD. This should be fine since
that is effectively a relaxation of the constructor's requirements.
rdar://86638350
Differential Revision: https://reviews.llvm.org/D116045
Microsoft would like to contribute its implementation of floating-point to_chars to libc++. This uses the impossibly fast Ryu and Ryu Printf algorithms invented by Ulf Adams at Google. Upstream repos: https://github.com/microsoft/STL and https://github.com/ulfjack/ryu .
Licensing notes: MSVC's STL is available under the Apache License v2.0 with LLVM Exception, intentionally chosen to match libc++. We've used Ryu under the Boost Software License.
This patch contains minor changes from Jorg Brown at Google, to adapt the code to libc++. He verified that it works in Google's Linux-based environment, but then I applied more changes on top of his, so any compiler errors are my fault. (I haven't tried to build and test libc++ yet.) Please tell me if we need to do anything else in order to follow https://llvm.org/docs/DeveloperPolicy.html#attribution-of-changes .
Notes:
* libc++'s integer charconv is unchanged (except for a small refactoring). MSVC's integer charconv hasn't been tuned for performance yet, so you're not missing anything.
* Floating-point from_chars isn't part of this patch because Jorg found that MSVC's implementation (derived from our CRT's strtod) was slower than Abseil's. If you're unable to use Abseil or another implementation due to licensing or technical considerations, Microsoft would be delighted if you used MSVC's from_chars (and you can just take it, or ask us to provide a patch like this). Ulf is also working on a novel algorithm for from_chars.
* This assumes that float is IEEE 32-bit, double is IEEE 64-bit, and long double is also IEEE 64-bit.
* I have added MSVC's charconv tests (the whole thing: integer/floating from_chars/to_chars), but haven't adapted them to libcxx's harness at all. (These tests will be available in the microsoft/STL repo soon.)
* Jorg added int128 codepaths. These were originally present in upstream Ryu, and I removed them from microsoft/STL purely for performance reasons (MSVC doesn't support int128; Clang on Windows does, but I found that x64 intrinsics were slightly faster).
* The implementation is split into 3 headers. In MSVC's STL, charconv contains only Microsoft-written code. xcharconv_ryu.h contains code derived from Ryu (with significant modifications and additions). xcharconv_ryu_tables.h contains Ryu's large lookup tables (they were sufficiently large to make editing inconvenient, hence the separate file). The xmeow.h convention is MSVC's for internal headers; you may wish to rename them.
* You should consider separately compiling the lookup tables (see https://github.com/microsoft/STL/issues/172 ) for compiler throughput and reduced object file size.
* See https://github.com/StephanTLavavej/llvm-project/commits/charconv for fine-grained history. (If necessary, I can perform some rebase surgery to show you what Jorg changed relative to the microsoft/STL repo; currently that's all fused into the first commit.)
Differential Revision: https://reviews.llvm.org/D70631
There's a lot of history behind this, so here's a summary:
1. I stopped forcing -fPIC when building the runtimes in 30f305efe2,
before the LLVM 9 release back in 2019.
2. Someone complained that libc++.a couldn't be used in shared libraries
built without -fPIC (http://llvm.org/PR43604) since the LLVM 9 release.
This had been caused by my removal of -fPIC when building libc++.a in (1).
3. I suggested two ways of fixing the issue, the first being to force
-fPIC back unconditionally (http://llvm.org/D104328), and the second
being to specify that option explicitly when building the LLVM release
(http://llvm.org/D104327). We converged on the first solution.
4. I landed D104328, which forced building the runtimes with -fPIC.
This was included in the LLVM 13.0 release.
5. People complained about that and requested that we be able to
customize this setting (basically we should have done the second
solution).
This patch makes it such that the LLVM release script will specifically
ask for building with -fPIC using CMAKE_POSITION_INDEPENDENT_CODE,
however by default the runtimes will not force that option onto users.
This patch has the unintended effect that Clang and the LLVM libraries
(not only the runtime ones like libc++) will also be built with -fPIC
in the release. It would be better if we could specify that -fPIC is to
be used only when building the runtimes, however this is left as a
future improvement. The release should probably be using a bootstrapping
build and passing those options to the stage that builds the runtimes
only, see https://reviews.llvm.org/D112748 for that change.
Differential Revision: https://reviews.llvm.org/D110261
Microsoft would like to contribute its implementation of floating-point to_chars to libc++. This uses the impossibly fast Ryu and Ryu Printf algorithms invented by Ulf Adams at Google. Upstream repos: https://github.com/microsoft/STL and https://github.com/ulfjack/ryu .
Licensing notes: MSVC's STL is available under the Apache License v2.0 with LLVM Exception, intentionally chosen to match libc++. We've used Ryu under the Boost Software License.
This patch contains minor changes from Jorg Brown at Google, to adapt the code to libc++. He verified that it works in Google's Linux-based environment, but then I applied more changes on top of his, so any compiler errors are my fault. (I haven't tried to build and test libc++ yet.) Please tell me if we need to do anything else in order to follow https://llvm.org/docs/DeveloperPolicy.html#attribution-of-changes .
Notes:
* libc++'s integer charconv is unchanged (except for a small refactoring). MSVC's integer charconv hasn't been tuned for performance yet, so you're not missing anything.
* Floating-point from_chars isn't part of this patch because Jorg found that MSVC's implementation (derived from our CRT's strtod) was slower than Abseil's. If you're unable to use Abseil or another implementation due to licensing or technical considerations, Microsoft would be delighted if you used MSVC's from_chars (and you can just take it, or ask us to provide a patch like this). Ulf is also working on a novel algorithm for from_chars.
* This assumes that float is IEEE 32-bit, double is IEEE 64-bit, and long double is also IEEE 64-bit.
* I have added MSVC's charconv tests (the whole thing: integer/floating from_chars/to_chars), but haven't adapted them to libcxx's harness at all. (These tests will be available in the microsoft/STL repo soon.)
* Jorg added int128 codepaths. These were originally present in upstream Ryu, and I removed them from microsoft/STL purely for performance reasons (MSVC doesn't support int128; Clang on Windows does, but I found that x64 intrinsics were slightly faster).
* The implementation is split into 3 headers. In MSVC's STL, charconv contains only Microsoft-written code. xcharconv_ryu.h contains code derived from Ryu (with significant modifications and additions). xcharconv_ryu_tables.h contains Ryu's large lookup tables (they were sufficiently large to make editing inconvenient, hence the separate file). The xmeow.h convention is MSVC's for internal headers; you may wish to rename them.
* You should consider separately compiling the lookup tables (see https://github.com/microsoft/STL/issues/172 ) for compiler throughput and reduced object file size.
* See https://github.com/StephanTLavavej/llvm-project/commits/charconv for fine-grained history. (If necessary, I can perform some rebase surgery to show you what Jorg changed relative to the microsoft/STL repo; currently that's all fused into the first commit.)
Differential Revision: https://reviews.llvm.org/D70631
This patch removes the ability to build the runtimes in the 32 bit
multilib configuration, i.e. using -m32. Instead of doing this, one
should cross-compile the runtimes for the appropriate target triple,
like we do for all other triples.
As it stands, -m32 has several issues, which all seem to be related to
the fact that it's not well supported by the operating systems that
libc++ support. The simplest path towards fixing this is to remove
support for the configuration, which is also the best course of action
if there is little interest for keeping that configuration. If there
is a desire to keep this configuration around, we'll need to do some
work to figure out the underlying issues and fix them.
Differential Revision: https://reviews.llvm.org/D114473
We only support Clangs that implement nullptr as an extension in C++03 mode,
and we don't support GCC in C++03 mode. Hence, this patch disables the
use of the std::nullptr_t emulation in C++03 mode by default. Doing that
is technically an ABI break since it changes the mangling for std::nullptr_t.
However:
(1) The only affected users are those compiling in C++03 mode that have
std::nullptr_t as part of their ABI, which should be reasonably rare.
(2) Those users already have a lingering problem in that their code will
be incompatible in C++03 and C++11 modes because of that very ABI break.
Hence, the only users that could really be inconvenienced about this
change is those that planned on compiling in C++03 mode forever - for
other users, we're just breaking them now instead of letting them break
themselves later on when they try to upgrade to C++11.
(3) The ABI break will cause a linker error since the mangling changed,
and will not result in an obscure runtime error.
Furthermore, if anyone is broken by this, they can define the
_LIBCPP_ABI_USE_CXX03_NULLPTR_EMULATION macro to return to the
previous behavior. We will then remove that macro after shipping
this for one release if we haven't seen widespread issues.
Concretely, the motivation for making this change is to make our own ABI
consistent in C++03 and C++11 modes and to remove complexity around the
definition of nullptr.
Furthermore, we could investigate making nullptr a keyword in C++03 mode
as a Clang extension -- I don't think that would break anyone, since
libc++ already defines nullptr as a macro to something else. Only users
that do not use libc++ and compile in C++03 mode could potentially be
broken by that.
Differential Revision: https://reviews.llvm.org/D109459
This effort is dedicated to deflake the tests of the users which depend
on the unspecified behavior of algorithms and containers. This also
might help updating the sorting algorithm in libcxx which has the
quadratic worst case in the future or at least create a new one under
flag.
For detailed design, please see the design doc I provide in the patch.
Differential Revision: https://reviews.llvm.org/D96946
These are not standard methods, neither libstdc++ nor MSVC STL provide
them.
In practice, one of them was untested and the other one was only used in
one single test.
Differential Revision: https://reviews.llvm.org/D113027
`is_error_condition_enum_v` and `is_error_code_enum_v` are currently of
type `size_t`, but the standard mandates they are of type `bool`.
This is an ABI break technically since the size of these variable
templates has changed. Document it as such in the release notes.
Fixes https://bugs.llvm.org/show_bug.cgi?id=50755
Reviewed By: ldionne, Quuxplusone, #libc, var-const
Differential Revision: https://reviews.llvm.org/D112553
Currently the member functions std::allocator<T>::allocate,
std::experimental::pmr::polymorphic_allocator::allocate and
std::resource_adaptor<T>::do_allocate throw an exception of type
std::length_error when the requested size exceeds the maximum size.
According to the C++ standard ([allocator.members]/4,
[mem.poly.allocator.mem]/1), std::allocator<T>::allocate and
std::pmr::polymorphic_allocator::allocate must throw a
std::bad_array_new_length exception in this case.
The patch fixes the issue with std::allocator<T>::allocate and changes
the type the exception thrown by
std::experimental::pmr::resource_adaptor<T>::do_allocate to
std::bad_array_new_length as well for consistency.
The patch resolves LWG 3237, LWG 3038 and LWG 3190.
Reviewed By: ldionne, #libc, Quuxplusone
Differential Revision: https://reviews.llvm.org/D110846
Several entries were in the wrong place, such as API changes appearing
under "Build System Changes". This commit shuffles stuff so it sits under
the right section.
This commit makes the new "runtimes" build (with <monorepo>/runtimes as
the root of the CMake invocation) the default way of building libc++.
The other supported way of building libc++ is the "bootstrapping" build,
where `<monorepo>/llvm` is used as the root of the CMake invocation.
All other ways of building libc++ are deprecated effective immediately.
There should be no use-case for building libc++ that isn't supported by
one of these two builds, and the two new builds work on all environments
and are lightweight. They will also make it possible to greatly simplify
the build infrastructure of the runtimes, which is currently way too
convoluted.
Differential Revision: https://reviews.llvm.org/D111356
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
While looking at the review comments in D103765 there was an oddity in
the tests for the following functions:
- atomic_fetch_add
- atomic_fetch_add_explicit
- atomic_fetch_sub
- atomic_fetch_sub_explicit
Libc++ allows usage of
`atomic_fetch_add<int>(atomic<int*>*, atomic<int*>::difference_type);`
MSVC and GCC reject this code: https://godbolt.org/z/9d8WzohbE
This makes the atomic `fetch(add|sub).*` Standard conforming and removes the non-conforming extensions.
Fixes PR47908
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D103983
This option is used to select between the format headers output column
width option. This option should be independent of the locale setting.
It's encouraged to default to Unicode unless the platform doesn't offer
that option.
[format.string.std]/10
```
For the purposes of width computation, a string is assumed to be in a
locale-independent, implementation-defined encoding. Implementations
should use a Unicode encoding on platforms capable of displaying Unicode
```
Reviewed By: #libc, ldionne, vitaut
Differential Revision: https://reviews.llvm.org/D103379
This implements the initial version of the `std::formatter` class and its specializations. It also implements the following formatting functions:
- `format`
- `vformat`
- `format_to`
- `vformat_to`
- `format_to_n`
- `formatted_size`
All functions have a `char` and `wchar_t` version. Parsing the format-spec and
using the parsed format-spec hasn't been implemented. The code isn't optimized,
neither for speed, nor for size.
The goal is to have the rudimentary basics working, which can be used as a
basis to improve upon. The formatters used in this commit are simple stubs that
will be replaced by real formatters in later commits.
The formatters that are slated to be replaced in this patch series don't have
an availability macro to avoid merge conflicts.
Note the formatter for `bool` uses `0` and `1` instead of "false" and
"true". This will be fixed when the stub is replaced with a real
formatter.
Implements parts of:
- P0645 Text Formatting
Completes:
- LWG3539 format_to must not copy models of output_iterator<const charT&>
Reviewed By: ldionne, #libc, vitaut
Differential Revision: https://reviews.llvm.org/D96664
This will allow us to use variant in common_iterator. We do this by introducing a new `__light_array` type that variant uses instead of `std::array`.
Differential Revision: https://reviews.llvm.org/D105597
Instead, people should be using CMAKE_POSITION_INDEPENDENT_CODE to control
whether they want to use PIC or not. We should try to avoid reinventing
the wheel whenever CMake natively supports something.
This makes libc++abi consistent with libc++ and libunwind.
Differential Revision: https://reviews.llvm.org/D103973
This patch gets rid of technical debt around std::pointer_safety which,
I claim, is entirely unnecessary. I don't think anybody has used
std::pointer_safety in actual code because we do not implement the
underlying garbage collection support. In fact, P2186 even proposes
removing these facilities entirely from a future C++ version. As such,
I think it's entirely fine to get rid of complex workarounds whose goals
were to avoid breaking the ABI back in 2017.
I'm putting this up both to get reviews and to discuss this proposal for
a breaking change. I think we should be comfortable with making these
tiny breaks if we are confident they won't hurt anyone, which I'm fairly
confident is the case here.
Differential Revision: https://reviews.llvm.org/D100410
This nasty patch rewrites the tuple constructors to match those defined
by the Standard. We were previously providing several extensions in those
constructors - those extensions are removed by this patch.
The issue with those extensions is that we've had numerous bugs filed
against us over the years for problems essentially caused by them. As a
result, people are unable to use tuple in ways that are blessed by the
Standard, all that for the perceived benefit of providing them extensions
that they never asked for.
Since this is an API break, I communicated it in the release notes.
I do not foresee major issues with this break because I don't think the
extensions are too widely relied upon, but we can ship it and see if we
get complaints before the next LLVM release - that will give us some
amount of information regarding how much use these extensions have.
Differential Revision: https://reviews.llvm.org/D96523
Some work-in-progress patches for the format header contain benchmarks.
The format header requires C++20 to build. This is a preparation to make
it easy to add these benchmarks.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D96057
This implements the std::filesystem parts of P0482 (which is already
marked as in progress), and applies the actions that are suggested
in P1423.
Differential Revision: https://reviews.llvm.org/D90222
Implements P1956: On the names of low-level bit manipulation functions.
Users may use older versions of libc++ or other standard libraries with the old names. In order to keep compatibility the old functions are kept, but marked as deprecated.
The patch also adds a new config macro `_LIBCPP_DEPRECATED_MSG`. Do you prefer a this is a separate patch?
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D90551
Previously, we would define new/delete in both libc++ and libc++abi.
Not only does this cause code bloat, but also it's technically an ODR
violation since we don't know which operator will be selected. Furthermore,
since those are weak definitions, we should strive to have as few of them
as possible (to improve load times).
My preferred choice would have been to put the operators in libc++ only
by default, however that would create a circular dependency between
libc++ and libc++abi, which GNU linkers don't handle.
Folks who want to ship new/delete in libc++ instead of libc++abi are
free to do so by turning on LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS at
CMake configure time.
On Apple platforms, this shouldn't be an ABI break because we re-export
the new/delete symbols from libc++abi. This change actually makes libc++
behave closer to the system libc++ shipped on Apple platforms.
On other platforms, this is an ABI break for people linking against libc++
but not libc++abi. However, vendors have been consulted in D68269 and no
objection was raised. Furthermore, the definitions can be controlled to
appear in libc++ instead with the CMake option.
Differential Revision: https://reviews.llvm.org/D68269
Summary:
std::bad_array_length was added by n3467, but this never made it into C++.
This commit removes the definition of std::bad_array_length from the headers
AND from the shared library. See the comments in the ABI changelog for details
about the ABI implications of this change.
Reviewers: mclow.lists, dexonsmith, howard.hinnant, EricWF
Subscribers: christof, jkorous, libcxx-commits
Differential Revision: https://reviews.llvm.org/D54804
llvm-svn: 347903
Summary:
std::dynarray had been proposed for C++14, but it was pulled out from C++14
and there are no plans to standardize it anymore.
Reviewers: mclow.lists, EricWF
Subscribers: mgorny, christof, jkorous, dexonsmith, arphaman, libcxx-commits
Differential Revision: https://reviews.llvm.org/D54801
llvm-svn: 347783
Summary:
This commit adopts the exclude_from_explicit_instantiation attribute discussed
at [1] and reviewed in [2] in libc++ to supplant the use of __always_inline__
for visibility purposes.
This change means that users wanting to link together translation units built
with different versions of libc++'s headers into the same final linked image
MUST define the _LIBCPP_HIDE_FROM_ABI_PER_TU macro to 1 when building those
TUs. Doing otherwise will lead to ODR violations and ABI issues.
[1]: http://lists.llvm.org/pipermail/cfe-dev/2018-August/059024.html
[2]: https://reviews.llvm.org/D51789
Reviewers: rsmith, EricWF
Subscribers: dexonsmith, libcxx-commits
Differential Revision: https://reviews.llvm.org/D52405
llvm-svn: 345516
libc++ has dropped support for Mac OS 10.6 for a while, and we don't
have any testers set up for that OS.
This commit puts in an error message so that people can reach out to
the libc++ maintainers in case support for 10.6 is still expected (as
opposed to silently failing in weird ways). We can completely drop
support for 10.6 and remove the error message some time in the future
when we're sure that nobody is relying on it.
llvm-svn: 344576