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
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
Implement the exposition-only concepts specified in
`[special.mem.concepts]`. These are all thin wrappers over other
concepts.
Reviewed By: #libc, Quuxplusone, ldionne
Differential Revision: https://reviews.llvm.org/D114761
Implement P1989R2 which adds a range constructor for `string_view`.
Adjust `operator/=` in `path` to avoid atomic constraints caching issue
getting provoked from this PR.
Add defaulted template argument to `string_view`'s "sufficient
overloads" to avoid mangling issues in `clang-cl` builds. It is a
MSVC mangling bug that this works around.
Differential Revision: https://reviews.llvm.org/D113161
This removes the `format_args_t` from `<format>` and adjusts the type of
the `format_args` for the `vformat_to` overloads.
The `format_context` uses a `back_insert_iterator<string>` therefore the
new `output_iterator` function uses a `string` as its temporary storage
buffer. This isn't ideal. The next patches in this series will improve
this. These improvements make it easy to also improve `format_to_n` and
`formatted_size`.
This addresses P2216 `6. Binary size`.
P2216 `5. Compile-time checks` are not part of this change.
Implements parts of:
- P2216 std::format improvements
Depends on D103670
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D110494
This does not include `std::compare_*_fallback`; those are coming later.
There's still an open question of how to implement std::strong_order
for `long double`, which has 80 value bits and 48 padding bits on x86-64,
and which is presumably *not* IEEE 754-compliant on PPC64 and so on.
So that part is left unimplemented.
Differential Revision: https://reviews.llvm.org/D110738
Mark [cmp.concept] implementation as completed in our documentation.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D114203
Since coroutine is merged in C++ standard and the support for coroutine
seems relatively stable. It's the time to move the implementation of
coroutine out of the experimental directory and the std::experimental
namespace. This patch creates header <coroutine> with conformed
implementation with C++ standard. To avoid breaking user's code too
fast, the <experimental/coroutine> header is remained. Note that
<experimental/coroutine> is deprecated and it would be removed in
LLVM15.
Reviewed By: Quuxplusone, ldionne
Differential Revision: https://reviews.llvm.org/D109433
Deduction guides for containers should not participate in overload
resolution when called with certain incorrect types (e.g. when called
with a template argument in place of an `InputIterator` that doesn't
qualify as an input iterator). Similarly, class template argument
deduction should not select `unique_ptr` constructors that take a
a pointer.
The tests try out every possible incorrect parameter (but never more
than one incorrect parameter in the same invocation).
Also add deduction guides to the synopsis for associative and unordered
containers (this was accidentally omitted from [D112510](https://reviews.llvm.org/D112510)).
Differential Revision: https://reviews.llvm.org/D112904
Most of the code has been implemented using the eel.is draft. It seems
some issues were inplemented but not marked as completed yet.
Note the wording of LWG-3372 has been implemented, but has been changed
in the current draft due to P2216, see D110494.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D112363
`libc++` has had the guarantee of the default constructor of `tuple<>` being
trivial since 405570dc7a. Now, the
standard mandates it as of LWG3211. So, move the file out of
`libcxx/test/libcxx` and into `libcxx/test/std` since it's no longer
`libc++`-specific. Rename it to be `.compile.pass.cpp` instead of
`.pass.cpp` while we're at it.
Reviewed By: ldionne, Quuxplusone, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D112743
Add deduction guides to `valarray` and `scoped_allocator_adaptor`. This largely
finishes implementation of the paper:
* deduction guides for other classes mentioned in the paper were
implemented previously (see the list below);
* deduction guides for several classes contained in the proposal
(`reference_wrapper`, `lock_guard`, `scoped_lock`, `unique_lock`,
`shared_lock`) were removed by [LWG2981](https://wg21.link/LWG2981).
Also add deduction guides to the synopsis for the few classes (e.g. `pair`)
where they were missing.
The only part of the paper that isn't fully implemented after this patch is
making sure certain deduction guides don't participate in overload resolution
when given incorrect template parameters.
List of significant commits implementing the other parts of P0433 (omitting some
minor fixes):
* [pair](af65856eec)
* [basic_string](6d9f750dec)
* [array](0ca8c0895c)
* [deque](dbb6f8a817)
* [forward_list](e076700b77)
* [list](4a227e582b)
* [vector](df8f754792)
* [queue/stack/priority_queue](5b8b8b5dce)
* [basic_regex](edd5e29cfe)
* [optional](f35b4bc395)
* [map/multimap](edfe8525de)
* [set/multiset](e20865c387)
* [unordered_set/unordered_multiset](296a80102a)
* [unordered_map/unordered_multimap](dfcd4384cb)
* [function](e1eabcdfad)
* [tuple](1308011e1b)
* [shared_ptr/weak_ptr](83564056d4)
Additional notes:
* It was revision 2 of the paper that was voted into the Standard.
P0433R3 is a separate paper that is not part of the Standard.
* The paper also mandates removing several `make_*_searcher` functions
(e.g. `make_boyer_moore_searcher`) which are currently not implemented
(except in `experimental/`).
* The `__cpp_lib_deduction_guides` feature test macro from the paper was
accidentally omitted from the Standard.
Differential Revision: https://reviews.llvm.org/D112510
Mark LWG2731 as complete. The type alias `mutex_type` is only provided if
`scoped_lock` is given one mutex type and it has been implemented that
way since the beginning of Clang 5 it seems. There already are tests for
verifying existence (and lack thereof) for `mutex_type` type alias
depending on the number of mutex types, so there is nothing to
do for this LWG issue.
Reviewed By: Quuxplusone, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D112462
Also fix a few places in the `shared_ptr` implementation where
`element_type` was passed to the `__is_compatible` helper. This could
result in `remove_extent` being applied twice to the pointer's template
type (first by the definition of `element_type` and then by the helper),
potentially leading to somewhat less readable error messages for some
incorrect code.
Differential Revision: https://reviews.llvm.org/D112092
Several of our C++20 and C++2b papers were missing the actual revision
number that was voted in to the Standard. The revision number is quite
important because in a few cases, a paper has a revision *after* the
one that is voted into the Standard, which isn't voted into the Standard.
Hence, if we simply followed the wg21.link blindly and implemented that,
we'd end up implementing the latest revision of the paper, which might
not have been voted.
As a fly-by fix, I found out that P1664 had been withdrawn from the
straw polls and had never been voted into the Standard. This commit
removes that entry from our list.
Differential Revision: https://reviews.llvm.org/D112339
Mark LWG3573 as complete. It involves a change in wording around when
`basic_string_view`'s constructor for iterator/sentinel can throw. The
current implementation is not marked conditionally `noexcept`, so there
is nothing to do here. Add a test that binds this behavior to verify the
constructor is not marked `noexcept(true)` when `end - begin` throws.
Reviewed By: ldionne, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D111925
Mark LWG3420 as complete. Currently, the `cpp17_iterator` concept
checks that the type looks like an iterator first before checking if it
is copyable.
Reviewed By: ldionne, Quuxplusone, #libc
Differential Revision: https://reviews.llvm.org/D111598
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
A followup to D111458 adding more labels to LWG-issues. This should add
the labels for the not completed chrono, format, ranges, and spaceship
issues.
Some minor formatting cleanups along the way.
Reviewed By: #libc, Quuxplusone
Differential Revision: https://reviews.llvm.org/D111935
During the review of D111166 I had a private discussion with @ldionne to
avoid the duplication of the C++2b issues in the Ranges and Format
status pages. The main reason for duplicating them is to make it easier to
find them. The title of the paper may not always make it clear to which
project the paper belongs.
This commit removes all LWG-issues from the Ranges and Format status page
and adds labels for these issue in the C++20/C++23 issues list.
A quick scan revealed there are some issues that are missing a label since
they weren't on the ranges issue list. These can be labelled in a separate
commit. In that commit I'll also look for issues for the spaceship operator
and chrono.
Reviewed By: Quuxplusone, ldionne, #libc
Differential Revision: https://reviews.llvm.org/D111458
Implement LWG3480 which enables `directory_iterator` and
`recursive_directory_iterator` to be both a `borrowed_range` and a
`view`.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D111644
Mark LWG3274 as complete. The feature test macro `__cpp_lib_span` was added in
`6d2599e4f776d0cd88438cb82a00c4fc25cc3f67`.
https://wg21.link/p1024 mentions marking `span:::empty()` with
`[[nodiscard]]` which is not done yet. So, do that and add tests.
Reviewed By: ldionne, Quuxplusone, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D111516
While looking at LWG-2988 and P0558 it seems the issues were already
implemented, but the synopsis wasn't updated. Some of the tests didn't
validate the `noexcept` status. A few tests were missing completely:
- `atomic_wait_explicit`
- `atomic_notify_one`
- `atomic_notify_all`
Mark P0558 as complete, didn't investigate which version of libc++ first
includes this. It seems the paper has been retroactively applied. I
couldn't find whether this is correct, but looking at cppreference it
seems intended.
Completes
- LWG-2988 Clause 32 cleanup missed one typename
- P0558 Resolving atomic<T> named base class inconsistencies
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D103765
Mark LWG3447 as complete since it was not an issue since the original
implementation of `take_view` from
0f4b41e038. Currently, `take_view`'s
deduction guide does not constrain the range on the `range` concept.
Reviewed By: ldionne, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D111501
Implement P2401 which adds a `noexcept` specification to
`std::exchange`. Treated as a defect fix which is the motivation for
applying this change to all standards mode rather than just C++23 or
later as the paper suggests.
Reviewed By: Quuxplusone, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D111481
Implement P2251 which requires `span` and `basic_string_view` to be
trivially copyable. They already are - this just adds tests to bind that
behavior.
Reviewed By: ldionne, Quuxplusone, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D111197
Implement parts of P1614, including three-way comparison for tuples, and expand testing.
Reviewed By: ldionne, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D108250
Update the status with the approved papers and LWG-issues in the October 2021 plenary.
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D111166
Implements the formatter for Boolean types.
[format.formatter.spec]/2.3
For each charT, for each cv-unqualified arithmetic type ArithmeticT other
than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
```
template<> struct formatter<ArithmeticT, charT>;
```
This removes the stub implemented in D96664.
Implements parts of:
- P0645 Text Formatting
- P1652 Printf corner cases in std::format
Completes:
- P1868 width: clarifying units of width and precision in std::format
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D103670
Implements the formatter for all fundamental integer types
(except `char`, `wchar_t`, and `bool`).
[format.formatter.spec]/2.3
For each charT, for each cv-unqualified arithmetic type ArithmeticT other
than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
```
template<> struct formatter<ArithmeticT, charT>;
```
This removes the stub implemented in D96664.
As an extension it adds partial support for 128-bit integer types.
Implements parts of:
- P0645 Text Formatting
- P1652 Printf corner cases in std::format
Completes:
- LWG-3248 #b, #B, #o, #x, and #X presentation types misformat negative numbers
Reviewed By: #libc, ldionne, vitaut
Differential Revision: https://reviews.llvm.org/D103433
Mark de Wever