llvm-project.git/libc/test/src/string, branch main

[libc] add an SVE implementation of strlen (#167259)

2025-11-11T00:15:34+00:00

This PR creates an SVE-based implementation for strlen by translating
from the AOR code in tree. Microbenchmark shows improvements against
NEON when N>=64. Although both implementations fall behind glibc by a
large margin,
this may be a good start point to explore SVE implementations.

Together with the PR:

1. Added two more tests of strlen with special nul symbols.
2. Added strlen's fuzzer and fix a typo in previous heap fuzzer.

```
=== strlen(16 bytes) ===
libc: 1.56115 ns/call, 9.54499 GiB/s
neon: 1.59393 ns/call, 9.34867 GiB/s
sve: 1.66097 ns/call, 8.97134 GiB/s

=== strlen(64 bytes) ===
libc: 2.06967 ns/call, 28.7991 GiB/s
neon: 2.59914 ns/call, 22.9325 GiB/s
sve: 2.58628 ns/call, 23.0465 GiB/s

=== strlen(256 bytes) ===
libc: 3.74165 ns/call, 63.7202 GiB/s
neon: 8.98243 ns/call, 26.5428 GiB/s
sve: 7.36426 ns/call, 32.3751 GiB/s

=== strlen(1024 bytes) ===
libc: 10.5327 ns/call, 90.5438 GiB/s
neon: 34.363 ns/call, 27.7529 GiB/s
sve: 26.9329 ns/call, 35.4092 GiB/s

=== strlen(4096 bytes) ===
libc: 37.7304 ns/call, 101.104 GiB/s
neon: 145.911 ns/call, 26.144 GiB/s
sve: 103.208 ns/call, 36.9612 GiB/s

=== strlen(1048576 bytes) ===
libc: 9623.4 ns/call, 101.478 GiB/s
neon: 36138.2 ns/call, 27.023 GiB/s
sve: 26605.6 ns/call, 36.7051 GiB/s
```

[libc] Fix stale char_ptr for find_first_character_wide read (#166594)

2025-11-06T14:48:14+00:00

On exit from the loop, char_ptr had not been updated to match block_ptr,
resulting in erroneous results. Moving all updates out of the loop fixes
that.

Adjust derefences to always be inside bounds checks.

[libc][NFC] Remove usage of the C keyword `I`. (#160567)

2025-09-24T18:18:32+00:00

[libc] Add -Wextra for libc tests (#153321)

2025-09-22T16:56:38+00:00

RE apply https://github.com/llvm/llvm-project/pull/133643/commits#top

[libc] Use anonymous namespace for test helper code (#157203)

2025-09-06T00:14:55+00:00

Tests can be at top-level or inside an anonymous namespace,
doesn't matter.  But putting their helper code inside anonymous
namespaces both makes the code compatible with compiling using
-Wmissing-declarations and might let the compiler optimize the
test good a bit better.

[libc] fixed signed char issues in strsep()/strtok()/strtok_r(). (#156705)

2025-09-03T18:00:38+00:00

Also add the missing tests for all the related functions (even the ones
that were already right), and add the missing bazel build rules.

[libc] fix strsep()/strtok()/strtok_r() "subsequent searches" behavior. (#154370)

2025-08-21T13:32:35+00:00

These functions turned out to have the same bug that was in wcstok()
(fixed by 4fc9801), so add the missing tests and fix the code in a way
that matches wcstok().

Also fix incorrect test expectations in existing tests.

Also update the BUILD.bazel files to actually build the strsep() test.

Revert "[libc] Add -Wextra for libc tests" (#153169)

2025-08-12T11:40:14+00:00

Reverts llvm/llvm-project#133643

[libc] Add -Wextra for libc tests (#133643)

2025-08-12T11:27:13+00:00

* Relates to: https://github.com/llvm/llvm-project/issues/119281

[libc] Don't rely on LIBC_HAS_SANITIZER when enabling null checks. (#150341)

2025-07-24T21:15:46+00:00

LIBC_HAS_SANITIZER (which is defined if ASan, MSan, or UBSan is enabled)
is currently used to implicitly disable null checks, normally enabled
via LIBC_ADD_NULL_CHECKS config value. Remove this condition, and rely
purely on the config value instead:

* LIBC_HAS_SANITIZER will be true even for UBSan modes which doesn't
rely on null checks at all (e.g. -fsanitize=alignment)
* null checks today (implemented via __builtin_trap) should function
normally today even when sanitizer is enabled - trap is still a trap
* tests have been migrated to WITH_SIGNAL(-1) which doesn't prescript a
particular signal / exit-code, and thus should pass even if sanitizers
override the default ones.