Without this patch `basic_string` cannot be properly resized to be
`max_size()` elements in size, even if an allocation is successful.
`__grow_by` allocates one less element than required, resulting in an
out-of-bounds access. At the same time, `max_size()` has an off-by-one
error, since there has to be space to store the null terminator, which
is currently ignored.
The current implementation of the `shrink_to_fit()` function of
`basic_string` swaps to the newly allocated buffer when the new buffer
has the same capacity as the existing one. While this is not incorrect,
it is truly unnecessary to swap to an equally-sized buffer. With equal
capacity, we should keep using the existing buffer and simply deallocate
the new one, avoiding the extra work of copying elements.
The desired behavior was documented in the following comment within the
function:
61ad08792a/libcxx/include/string (L3560-L3566)
However, the existing implementation did not exactly conform to this
guideline, which is a QoI matter.
This PR modifies the `shrink_to_fit()` function to ensure that the
buffer is only swapped when the new allocation is strictly smaller than
the existing one. When the capacities are equal, the new buffer will be
discarded without copying the elements. This is achieved by including
the `==` check in the above conditional logic.
The test would not check its absence and the code path intended for
pointer was never actually instantiated.
I added a few pointer types since there was no coverage.
---------
Co-authored-by: Louis Dionne <ldionne.2@gmail.com>
Completes:
- LWG3359 <chrono> leap second support should allow for negative leap
seconds
- P1361R2 Integration of chrono with text formatting
Implements parts of:
- P0355 Extending <chrono> to Calendars and Time Zones
Fixes: #100432Fixes: #100014
This is technically not necessary in most cases to prevent issues with ADL,
but let's be consistent. This allows us to remove the libcpp-qualify-declval
clang-tidy check, which is now enforced by the robust-against-adl clang-tidy check.
Many parts of the locale base API are only required when building the
shared/static library, but not from the headers. Document those
functions and carve out a few of those that don't work when
_XOPEN_SOURCE is defined to something old.
Fixes#117630
This refactor includes the following changes:
- Refactor similar tests using `types::for_each` to remove redundant code;
- Explicitly include the missing header `type_algorithms.h` in some test files;
- Some tests scattered in different test functions with ad-hoc names
(e.g., `test5()`, `test6()`) but belong to the same kind are now grouped
into one function (`test_struct_array()`).
As a follow-up to #121013 (which optimized `ranges::copy`) and #121026
(which optimized `ranges::copy_backward`), this PR enhances the
performance of `std::ranges::{move, move_backward}` for
`vector<bool>::iterator`, addressing a subtask outlined in issue #64038.
The optimizations bring performance improvements analogous to those
achieved for the `{copy, copy_backward}` algorithms: up to 2000x for
aligned moves and 60x for unaligned moves. Moreover, comprehensive
tests covering up to 4 storage words (256 bytes) with odd and even bit
sizes are provided, which validate the proposed optimizations in this
patch.
These member types were deprecated in C++17 by P0174R2 and removed in
C++20 by P0619R4, but the changes in `<variant>` seem missing.
Drive-by: Replace one `_NOEXCEPT` with `noexcept` as the `hash`
specialization is C++17-and-later only.
All non-existing local times in a contiguous range should map to the
same time point. This fixes a bug, were the times inside the range were
mapped to the wrong time.
Fixes: #113654
Asan reports it after #124103.
It's know case of false positive for Asan.
https://github.com/google/sanitizers/wiki/AddressSanitizerInitializationOrderFiasco#false-positives
It's can be avoided with `constexpr` constructors.
In general order global constructors in different
modules is undefined. If global constructor uses
external global, they can be not constructed yet.
However, implementation may contain workaround for
that, or the state of non-constructed global can
be still valid.
Asan will still falsely report such cases, as it
has no machinery to detect correctness of such
cases.
We need to fix/workaround the issue in libc++, as
it will affect many libc++ with Asan users.
The operators did not have a _Compare template arguement. The fix
updates the generic container test to use allocators for all types used.
No other issues were found.
Fixes: #127095
We have some benchmarks that were benchmarking very specific
functionality, namely the optimizations in vector<bool>::iterator. Call
this out in the benchmarks by renaming them appropriately. In the future
we will also increase the coverage of these benchmarks to test other
containers.
On older MacOS versions where `std::to_chars` for floating-point types
is not available the format library can't be used. Due to some issue
with the availability macro used to disable format on MacOS the issue
triggers regardless of the type being formatted.
The print library has the same issue.
Fixes: #125353
We've been improving these the tests for vector quite a bit and we are
probably not done improving our container tests. Formatting everything
at once will make subsequent reviews easier.
Currently `std::hash<Emplaceable>::operator()` relies implicit
conversion from `int` to `size_t`, which makes MSVC compelling. This PR
switches to use `static_cast`.
In `flat.map/flat.map.access/at_transparent.pass.cpp`, there's one
value-discarding use of `at` that wasn't marked `TEST_IGNORE_NODISCARD`.
This PR adds the missing `TEST_IGNORE_NODISCARD`.
Summary:
Currently we conditionally enable NVPTX lowering depending on the
language (C/C++/OpenMP). Unfortunately this causes problems because this
option is only present if the backend was enabled, which causes this to
error if you try to make LLVM-IR.
This patch instead makes it the only accepted lowering. The reason we
had it as opt-in before is because it is not handled by CUDA. So, this
pach also introduces diagnostics to prevent *all* creation of
device-side global constructors and destructors. We already did this for
variables, now we do it for attributes as well.
This inverts the responsibility of blocking this from the backend to the
langauage like it should be given that support for this is language
dependent.
This changes the code to use dataclasses instead of dict entries. It
also adds type aliases to use in the typing information and updates the
typing information.
`MinSequenceContainer::size` can be narrowing on 64-bit platforms, and
MSVC complains about such implicit conversion. This PR changes the
implicit conversion to explicit `static_cast`.
`min_allocator::allocate` and `min_allocator::deallocate` have
`ptrdiff_t` as the parameter type, which seems weird, because the
underlying `std::allocator`'s member functions take `size_t`. It seems
better to use `size_t` consistently.
This patch does not significantly change how the sequence container
benchmarks are done, but it adopts the same style as the associative
container benchmarks.
This commit does adjust how we were benchmarking push_back, where we
never really measured the overhead of the slow path of push_back (when
we need to reallocate).
This patch implements generic associative container benchmarks for
containers with unique keys. In doing so, it replaces the existing
std::map benchmarks which were based on the cartesian product
infrastructure and were too slow to execute.
These new benchmarks aim to strike a balance between exhaustive coverage
of all operations in the most interesting case, while executing fairly
rapidly (~40s on my machine).
This bumps the requirement for the map benchmarks from C++17 to C++20
because the common header that provides associative container benchmarks
requires support for C++20 concepts.
Implements parts of:
- P0355 Extending <chrono> to Calendars and Time Zones
- P1361 Integration of chrono with text formatting
- LWG3359 <chrono> leap second support should allow for negative leap
seconds
The capacity is now passed correctly and a test for this path is added.
Since we changed the implementation of `reserve(size_type)` to only ever
extend,
it doesn't make a ton of sense anymore to have `__shrink_or_extend`,
since the code
paths of `reserve` and `shrink_to_fit` are now almost completely
separate.
This patch splits up `__shrink_or_extend` so that the individual parts
are in `reserve`
and `shrink_to_fit` depending on where they are needed.
This reverts commit 59f57be94f38758616b1339b293b43af845571af.
This PR slightly simplifies the implementation of `vector<bool>::max_size`
and adds extensive tests for the `max_size()` function for both `vector<bool>`
and `vector<T>`. The main purposes of the new tests include:
- Verify correctness of `max_size()` under various `size_type` and
`difference_type` definitions: check that `max_size()` works properly
with allocators that have custom `size_type` and `difference_type`. This
is particularly useful for `vector<bool>`, as different `size_type` lead
to different `__storage_type` of different word lengths, resulting in
varying `max_size()` values for `vector<bool>`. Additionally, different
`difference_type` also sets different upper limit of `max_size()` for
both `vector<bool>` and `std::vector`. These tests were previously
missing.
- Eliminate incorrect implementations: Special tests are added to identify and
reject incorrect implementations of `vector<bool>::max_size` that unconditionally
return `std::min<size_type>(size-max, __internal_cap_to_external(allocator-max-size))`.
This can cause overflow in the `__internal_cap_to_external()` call and lead
to incorrect results. The new tests ensure that such incorrect
implementations are identified.
The __is_trivially_relocatable builtin has semantics that do not
correspond to any current or future notion of trivial relocation.
Furthermore, it currently leads to incorrect optimizations for some
types on supported compilers:
- Clang on Windows where types with non-trivial destructors get
incorrectly optimized
- AppleClang where types with non-trivial move constructors get
incorrectly optimized
Until there is an agreed upon and bugfree implementation of what it
means to be trivially relocatable, it is safer to simply use trivially
copyable instead. This doesn't leave a lot of types behind and is
definitely correct.
This PR addresses an undefined behavior that arises when using the
`std::fill` and `std::fill_n` algorithms, as well as their ranges
counterparts `ranges::fill` and `ranges::fill_n`, with `vector<bool, Alloc>`
that utilizes a custom-sized allocator with small integral types.
The previous tested TZDB did not contain %z for the rule letters. The
usage of %z in TZDB 2024b revealed a bug in the implementation. The
patch fixes it and has been locally tested with TZDB 2024b.
Fixes#108957
Rewrite the sequence container benchmarks to only rely on the actual
operations specified in SequenceContainer requirements and add
benchmarks for std::list, which is also considered a sequence container.
One of the major goals of this refactoring is also to make these
container benchmarks run faster so that they can be run more frequently.
The existing benchmarks have the significant problem that they take so
long to run that they must basically be run overnight. This patch
reduces the size of inputs such that the rewritten benchmarks each take
at most a minute to run.
This patch doesn't touch the string benchmarks, which were not using the
generic container benchmark functions previously.
As a follow-up to #121013 (which focused on `std::ranges::copy`), this
PR optimizes the performance of `std::ranges::copy_backward` for
`vector<bool>::iterator`, addressing a subtask outlined in issue #64038.
The optimizations yield performance improvements of up to 2000x for
aligned copies and 60x for unaligned copies.
