13 Commits

Author SHA1 Message Date
Nikolas Klauser
34d4f0c136
[libc++][NFC] Use llvm.org/PR to link to bug reports (#156288)
We've built up quite a few links directly to github within the code
base. We should instead use `llvm.org/PR<issue-number>` to link to bugs,
since that is resilient to the bug tracker changing in the future. This
is especially relevant for tests linking to bugs, since they will
probably be there for decades to come. A nice side effect is that these
links are significantly shorter than the GH links, making them much less
of an eyesore.

This patch also replaces a few links that linked to the old bugzilla
instance on llvm.org.
2025-09-04 09:20:02 +02:00
Peng Liu
a5b3d3a03f
[libc++] Fix {std, ranges}::copy for vector<bool> with small storage types (#131545)
The current implementation of `{std, ranges}::copy` fails to copy
`vector<bool>` correctly when the underlying storage type
(`__storage_type`) is smaller than `int`, such as `unsigned char`,
`unsigned short`, `uint8_t` and `uint16_t`. The root cause is that the
unsigned small storage type undergoes integer promotion to (signed)
`int`, which is then left and right shifted, leading to UB (before
C++20) and sign-bit extension (since C++20) respectively. As a result,
the underlying bit mask evaluations become incorrect, causing erroneous
copying behavior.

This patch resolves the issue by correcting the internal bitwise
operations, ensuring that `{std, ranges}::copy` operates correctly for
`vector<bool>` with any custom (unsigned) storage types.

Fixes #131692.
2025-03-19 11:55:51 -04:00
Peng Liu
5b65896ad6
[libc++] Optimize ranges::copy{, _n} for vector<bool>::iterator (#121013)
This PR optimizes the performance of `std::ranges::copy` and
`std::ranges::copy_n` specifically 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. Additionally, new tests have been added to
validate these enhancements.


- Aligned source-destination bits

ranges::copy
```
--------------------------------------------------------------------------
Benchmark                                Before        After   Improvement
--------------------------------------------------------------------------
bm_ranges_copy_vb_aligned/8              10.8 ns      1.42 ns           8x
bm_ranges_copy_vb_aligned/64             88.5 ns      2.28 ns          39x
bm_ranges_copy_vb_aligned/512             709 ns      1.95 ns         364x
bm_ranges_copy_vb_aligned/4096           5568 ns      5.01 ns        1111x
bm_ranges_copy_vb_aligned/32768         44754 ns      38.7 ns        1156x
bm_ranges_copy_vb_aligned/65536         91092 ns      73.2 ns        1244x
bm_ranges_copy_vb_aligned/102400       139473 ns       127 ns        1098x
bm_ranges_copy_vb_aligned/106496       189004 ns      81.5 ns        2319x
bm_ranges_copy_vb_aligned/110592       153647 ns      71.1 ns        2161x
bm_ranges_copy_vb_aligned/114688       159261 ns      70.2 ns        2269x
bm_ranges_copy_vb_aligned/118784       181910 ns      73.5 ns        2475x
bm_ranges_copy_vb_aligned/122880       174117 ns      76.5 ns        2276x
bm_ranges_copy_vb_aligned/126976       176020 ns      82.0 ns        2147x
bm_ranges_copy_vb_aligned/131072       180757 ns       137 ns        1319x
bm_ranges_copy_vb_aligned/135168       190342 ns       158 ns        1205x
bm_ranges_copy_vb_aligned/139264       192831 ns       103 ns        1872x
bm_ranges_copy_vb_aligned/143360       199627 ns      89.4 ns        2233x
bm_ranges_copy_vb_aligned/147456       203881 ns      88.6 ns        2301x
bm_ranges_copy_vb_aligned/151552       213345 ns      88.4 ns        2413x
bm_ranges_copy_vb_aligned/155648       216892 ns      92.9 ns        2335x
bm_ranges_copy_vb_aligned/159744       222751 ns      96.4 ns        2311x
bm_ranges_copy_vb_aligned/163840       225995 ns       173 ns        1306x
bm_ranges_copy_vb_aligned/167936       235230 ns       202 ns        1165x
bm_ranges_copy_vb_aligned/172032       244093 ns       131 ns        1863x
bm_ranges_copy_vb_aligned/176128       244434 ns       111 ns        2202x
bm_ranges_copy_vb_aligned/180224       249570 ns       108 ns        2311x
bm_ranges_copy_vb_aligned/184320       254538 ns       108 ns        2357x
bm_ranges_copy_vb_aligned/188416       261817 ns       113 ns        2317x
bm_ranges_copy_vb_aligned/192512       269923 ns       125 ns        2159x
bm_ranges_copy_vb_aligned/196608       273494 ns       210 ns        1302x
bm_ranges_copy_vb_aligned/200704       280035 ns       269 ns        1041x
bm_ranges_copy_vb_aligned/204800       293102 ns       231 ns        1269x
```

ranges::copy_n
```
--------------------------------------------------------------------------
Benchmark                                Before        After   Improvement
--------------------------------------------------------------------------
bm_ranges_copy_n_vb_aligned/8            11.8 ns       0.89 ns         13x
bm_ranges_copy_n_vb_aligned/64           91.6 ns       2.06 ns         44x
bm_ranges_copy_n_vb_aligned/512           718 ns       2.45 ns        293x
bm_ranges_copy_n_vb_aligned/4096         5750 ns       5.02 ns       1145x
bm_ranges_copy_n_vb_aligned/32768       45824 ns       40.9 ns       1120x
bm_ranges_copy_n_vb_aligned/65536       92267 ns       73.8 ns       1250x
bm_ranges_copy_n_vb_aligned/102400     143267 ns       125 ns        1146x
bm_ranges_copy_n_vb_aligned/106496     148625 ns      82.4 ns        1804x
bm_ranges_copy_n_vb_aligned/110592     154817 ns      72.0 ns        2150x
bm_ranges_copy_n_vb_aligned/114688     157953 ns      70.4 ns        2244x
bm_ranges_copy_n_vb_aligned/118784     162374 ns      71.5 ns        2270x
bm_ranges_copy_n_vb_aligned/122880     168638 ns      72.9 ns        2313x
bm_ranges_copy_n_vb_aligned/126976     175596 ns      76.6 ns        2292x
bm_ranges_copy_n_vb_aligned/131072     181164 ns       135 ns        1342x
bm_ranges_copy_n_vb_aligned/135168     184697 ns       157 ns        1176x
bm_ranges_copy_n_vb_aligned/139264     191395 ns       104 ns        1840x
bm_ranges_copy_n_vb_aligned/143360     194954 ns      88.3 ns        2208x
bm_ranges_copy_n_vb_aligned/147456     208917 ns      86.1 ns        2426x
bm_ranges_copy_n_vb_aligned/151552     211101 ns      87.2 ns        2421x
bm_ranges_copy_n_vb_aligned/155648     213175 ns      89.0 ns        2395x
bm_ranges_copy_n_vb_aligned/159744     218988 ns      86.7 ns        2526x
bm_ranges_copy_n_vb_aligned/163840     225263 ns       156 ns        1444x
bm_ranges_copy_n_vb_aligned/167936     230725 ns       184 ns        1254x
bm_ranges_copy_n_vb_aligned/172032     235795 ns       119 ns        1981x
bm_ranges_copy_n_vb_aligned/176128     241145 ns       101 ns        2388x
bm_ranges_copy_n_vb_aligned/180224     250680 ns      99.5 ns        2519x
bm_ranges_copy_n_vb_aligned/184320     262954 ns      99.7 ns        2637x
bm_ranges_copy_n_vb_aligned/188416     258584 ns       103 ns        2510x
bm_ranges_copy_n_vb_aligned/192512     267190 ns       125 ns        2138x
bm_ranges_copy_n_vb_aligned/196608     270821 ns       213 ns        1271x
bm_ranges_copy_n_vb_aligned/200704     279532 ns       262 ns        1067x
bm_ranges_copy_n_vb_aligned/204800     283412 ns       222 ns        1277x
```

- Unaligned source-destination bits
```
--------------------------------------------------------------------------------
Benchmark                                    Before           After  Improvement
--------------------------------------------------------------------------------
bm_ranges_copy_vb_unaligned/8               12.8 ns         8.59 ns         1.5x
bm_ranges_copy_vb_unaligned/64              98.2 ns         8.24 ns          12x
bm_ranges_copy_vb_unaligned/512              755 ns         18.1 ns          42x
bm_ranges_copy_vb_unaligned/4096            6027 ns          102 ns          59x
bm_ranges_copy_vb_unaligned/32768          47663 ns          774 ns          62x
bm_ranges_copy_vb_unaligned/262144        378981 ns         6455 ns          59x
bm_ranges_copy_vb_unaligned/1048576      1520486 ns        25942 ns          59x
bm_ranges_copy_n_vb_unaligned/8             11.3 ns         8.22 ns         1.4x
bm_ranges_copy_n_vb_unaligned/64            97.3 ns         7.89 ns          12x
bm_ranges_copy_n_vb_unaligned/512            747 ns         18.1 ns          41x
bm_ranges_copy_n_vb_unaligned/4096          5932 ns         99.0 ns          60x
bm_ranges_copy_n_vb_unaligned/32768        47776 ns         749 ns           64x
bm_ranges_copy_n_vb_unaligned/262144      378802 ns        6576 ns           58x
bm_ranges_copy_n_vb_unaligned/1048576    1547234 ns       26229 ns           59x
```
2025-01-30 17:26:26 +01:00
Duo Wang
d05bada592
[libcxx][test] std::array::iterator are not pointers by C++ standard (#70729)
This is to modify a list of libcxx tests written under the assumption
that iterators for std::array, std::string_view, and std::string are
pointers. The motivation for this PR is to make the tests more universal
and potentially being used to test other C++ standard library
implementations, for example
[microsoft/STL](https://github.com/microsoft/STL).

I can confirm that this patch makes a number of tests compatible with
microsoft STL:
`Failed :  204 (2.12%)`  ->  `Failed :  136 (1.42%)`
, and does not break any tests on `libcxx`.

This is not a complete list of such incompatibilities, but I am hoping
this will start a discussion about whether we are open to accepting such
changes.
2023-11-12 17:30:15 +01:00
Arthur O'Dwyer
f56dfb78aa [libc++] Fix modules issues on OS X
First, fix a collision with the Point type from MacTypes.h, which was
reported on Slack, 2022-07-31: https://cpplang.slack.com/archives/C2X659D1B/p1659284691275889

Second, rename the meta:: namespace to types::. OSX's "/usr/include/ncurses.h"
defines a `meta` function, and is (for some reason) included in
"<SDK>/usr/include/module.modulemap", so that identifier is off-limits
for us to use in anything that compiles with -fmodules:

    libcxx/test/support/type_algorithms.h:16:11: error: redefinition of 'meta' as different kind of symbol
    namespace meta {
               ^
    <SDK>/usr/include/ncurses.h:603:28: note: previous definition is here
    extern NCURSES_EXPORT(int) meta (WINDOW *,bool);                        /* implemented */
                                ^

Finally, add a CI configuration for modules on OS X to make sure it
does not regress.

Differential Revision: https://reviews.llvm.org/D144915
2023-03-01 10:33:40 -05:00
Nikolas Klauser
c90801457f [libc++] Refactor deque::iterator algorithm optimizations
This has multiple benefits:
- The optimizations are also performed for the `ranges::` versions of the algorithms
- Code duplication is reduced
- it is simpler to add this optimization for other segmented iterators,
  like `ranges::join_view::iterator`
- Algorithm code is removed from `<deque>`

Reviewed By: ldionne, huixie90, #libc

Spies: mstorsjo, sstefan1, EricWF, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D132505
2023-01-19 20:11:43 +01:00
Nikolas Klauser
1323461fe7 [libc++] Add utilites for instantiating functions with multiple types
We currently call a lot of functions with the same list of types. To avoid forgetting any of them, this patch adds type_lists and utilities for it. Specifically, it adds
- `type_list` - This is just a list of types
- `concatenate` - This allows concatenating type_lists
- `for_each` - Iterate over a type_list

Reviewed By: ldionne, #libc

Spies: jloser, EricWF, libcxx-commits

Differential Revision: https://reviews.llvm.org/D137476
2022-11-21 20:35:06 +01:00
Vitaly Buka
a6e1080b87 Revert "[libc++][ranges]Refactor copy{,_backward} and move{,_backward}"
Breaks msan, asan

https://lab.llvm.org/buildbot/#/builders/5/builds/27904

This reverts commit 005916de58f73aa5c4264c084ba7b0e21040d88f.
2022-10-02 16:23:35 -07:00
Konstantin Varlamov
005916de58 [libc++][ranges]Refactor copy{,_backward} and move{,_backward}
Instead of using `reverse_iterator`, share the optimization between the 4 algorithms. The key observation here that `memmove` applies to both `copy` and `move` identically, and to their `_backward` versions very similarly. All algorithms now follow the same pattern along the lines of:
```
if constexpr (can_memmove<InIter, OutIter>) {
  memmove(first, last, out);
} else {
  naive_implementation(first, last, out);
}
```
A follow-up will delete `unconstrained_reverse_iterator`.

This patch removes duplication and divergence between `std::copy`, `std::move` and `std::move_backward`. It also improves testing:
- the test for whether the optimization is used only applied to `std::copy` and, more importantly, was essentially a no-op because it would still pass if the optimization was not used;
- there were no tests to make sure the optimization is not used when the effect would be visible.

Differential Revision: https://reviews.llvm.org/D130695
2022-10-01 17:35:12 -07:00
Louis Dionne
b8cb1dc9ea [libc++] Make <ranges> non-experimental
When we ship LLVM 16, <ranges> won't be considered experimental anymore.
We might as well do this sooner rather than later.

Differential Revision: https://reviews.llvm.org/D132151
2022-08-18 16:59:58 -04:00
Nikolas Klauser
e01b4fe956 [libc++] Fix unwrapping ranges with different iterators and sentinels
Reviewed By: ldionne, huixie90, #libc

Spies: arichardson, sstefan1, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D129040
2022-07-28 10:22:41 +02:00
Hui Xie
a81cc1fc07 [libcxx][ranges] Create a test tool ProxyIterator that customises iter_move and iter_swap
It is meant to be used in ranges algorithm tests.
It is much simplified version of C++23's tuple + zip_view.
Using std::swap would cause compilation failure and using `std::move` would not create the correct rvalue proxy which would result in copies.

Differential Revision: https://reviews.llvm.org/D129099
2022-07-08 00:00:21 +01:00
Nikolas Klauser
1d83750f63 [libc++] Implement ranges::copy{, _n, _if, _backward}
Reviewed By: Mordante, var-const, #libc

Spies: sstefan1, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D122982
2022-04-15 13:44:11 +02:00