This reverts commit 1e6e845d49a336e9da7ca6c576ec45c0b419b5f6 because it
changed the 1st parameter of adjust() to be unsigned, but libc itself
calls adjust() with a negative argument in align_backward() in
op_generic.h.
Followup to #127523
There were some test failures on arm32 after enabling Wconversion. There
were some tests that were failing due to missing casts. Also I changed
BigInt's `safe_get_at` back to being signed since it needed the ability
to be negative.
Update string_utils' string_length to work with char* or wchar_t*, so that it
may be reusable when implementing wmemchr, wcspbrk, wcsrchr, wcsstr.
Link: #121183
Link: #124027
Co-authored-by: Nick Desaulniers <ndesaulniers@google.com>
---------
Co-authored-by: Tristan Ross <tristan.ross@midstall.com>
docgen relies on the convention that we have a file foo.cpp in
libc/src/\<header\>/. Because the above functions weren't in libc/src/strings/
but rather libc/src/string/, docgen could not find that we had implemented
these.
Rather than add special carve outs to docgen, let's fix up our sources for
these 7 functions to stick with the existing conventions the rest of the
codebase follows.
Link: #118860Fixes: #118875
- migrate more `-O3` to `${libc_opt_high_flag}`
- workaround a issue with `LLP64` in test. The overflow testing is
guarded by a constexpr but the literal overflow itself will still
trigger warnings.
Notice that for math smoke test, for some reasons, the
`${libc_opt_high_flag}` will be passed into `lld-link` which confuses
the linker so there are still some warnings leftover there. I can
investigate more when I have time.
`strrchr("foo", '\0')` is defined to point to the end of `foo`, rather
than returning NULL. This wasn't caught by tests, since llvm-libc's
`ASSERT_STREQ(nullptr, "");` is not an assertion error.
While I'm here, refactor the test slightly to check for NULL more
specifically. I considered adding fancier `ASSERT`s (and changing the
semantics of `ASSERT_STREQ`), but opted for a more local fix by fair
dice roll.
When running Bionic's testsuite over llvm-libc, tests broke because
e.g.,
```
const char *str = "abc";
char buf[7]{"111111"};
strlcpy(buf, str, 7);
ASSERT_EQ(buf, {'1', '1', '1', '\0', '\0', '\0', '\0'});
```
On my machine (Debian w/ glibc and clang-16), a `printf` loop over `buf`
gets unrolled into a series of const `printf` at compile-time:
```
printf("%d\n", '1');
printf("%d\n", '1');
printf("%d\n", '1');
printf("%d\n", 0);
printf("%d\n", '1');
printf("%d\n", '1');
printf("%d\n", 0);
```
Seems best to match existing precedent here.
When using `-mprefer-vector-width=128` with `-march=sandybridge` copying
3 cache lines in one go (192B) gets converted into `rep;movsb` which
translate into a 60% hit in performance.
Consecutive calls to `__builtin_memcpy_inline` (implementation behind
`builtin::Memcpy::block_offset`) are not coalesced by the compiler and
so calling it three times in a row generates the desired assembly. It
only differs in the interleaving of the loads and stores and does not
affect performance.
This is needed to reland
https://github.com/llvm/llvm-project/pull/108939.
The patch primarily cleans up some incorrect includes. The `LIBC_INLINE`
macro is defined in `attributes.h`, not `config.h`. There appears to be
no need to change the CMake and Bazel build files.
Summary:
This adds the locale variants of the string functions. As previously,
these do not use the locale information at all and simply copy the
non-locale version which expects the "C" locale.
Currently when `LIBC_COPT_MEMCPY_X86_USE_SOFTWARE_PREFETCHING` is set we
prefetch memory for read on the source buffer. This patch adds prefetch
for write on the destination buffer.
This patch adds tests for `memcpy` and `memset` making sure that we
don't access buffers out of bounds. It relies on POSIX `mmap` /
`mprotect` and works only when FULL_BUILD_MODE is disabled.
The bug showed up while enabling software prefetching.
`loop_and_tail_offset` is always running at least one iteration but in
some configurations loop unrolled prefetching was actually needing only
the tail operation and no loop iterations at all.
Fixes#86546 and removes the macro `LIBC_HAS_BUILTIN`. This was
necessary to support older compilers that did not support
`__has_builtin`. All of the compilers we support already have this
builtin.
See: https://libc.llvm.org/compiler_support.html
All uses now use `__has_builtin` directly
cc @nickdesaulniers
Fixes:
libc/src/string/memory_utils/utils.h:345:13: warning: invalid case style
for member 'offset_' [readability-identifier-naming]
Having a trailing underscore for members is a google3 style, not LLVM style.
Removing the underscore is insufficient, as we would then have 2 members with
the same identifier which is not allowed (it is a compile time error). Remove
the getter, and just access the renamed member that's now made public.
Found via:
$ ninja -k2000 libc-lint 2>&1 | grep readability-identifier-naming
Auto fixed via:
$ clang-tidy -p build/compile_commands.json \
-checks="-*,readability-identifier-naming" \
<filename> --fix
This doesn't fix all instances, just the obvious simple cases where it makes
sense to change the identifier names. Subsequent PRs will fix up the
stragglers.
Codify that we use lower_case for
readability-identifier-naming.ConstexprFunctionCase and then fix the 11
violations (rather than codify UPPER_CASE and have to fix the 170 violations).
Towards the goal of getting `ninja libc-lint` back to green, fix the numerous
instances of:
warning: header guard does not follow preferred style [llvm-header-guard]
This is because many of our header guards start with `__LLVM` rather than
`LLVM`.
To filter just these warnings:
$ ninja -k2000 libc-lint 2>&1 | grep llvm-header-guard
To automatically apply fixits:
$ find libc/src libc/include libc/test -name \*.h | \
xargs -n1 -I {} clang-tidy {} -p build/compile_commands.json \
-checks='-*,llvm-header-guard' --fix --quiet
Some manual cleanup is still necessary as headers that were missing header
guards outright will have them inserted before the license block (we prefer
them after).
Summary:
This is a massive patch because it reworks the entire build and
everything that depends on it. This is not split up because various bots
would fail otherwise. I will attempt to describe the necessary changes
here.
This patch completely reworks how the GPU build is built and targeted.
Previously, we used a standard runtimes build and handled both NVPTX and
AMDGPU in a single build via multi-targeting. This added a lot of
divergence in the build system and prevented us from doing various
things like building for the CPU / GPU at the same time, or exporting
the startup libraries or running tests without a full rebuild.
The new appraoch is to handle the GPU builds as strict cross-compiling
runtimes. The first step required
https://github.com/llvm/llvm-project/pull/81557 to allow the `LIBC`
target to build for the GPU without touching the other targets. This
means that the GPU uses all the same handling as the other builds in
`libc`.
The new expected way to build the GPU libc is with
`LLVM_LIBC_RUNTIME_TARGETS=amdgcn-amd-amdhsa;nvptx64-nvidia-cuda`.
The second step was reworking how we generated the embedded GPU library
by moving it into the library install step. Where we previously had one
`libcgpu.a` we now have `libcgpu-amdgpu.a` and `libcgpu-nvptx.a`. This
patch includes the necessary clang / OpenMP changes to make that not
break the bots when this lands.
We unfortunately still require that the NVPTX target has an `internal`
target for tests. This is because the NVPTX target needs to do LTO for
the provided version (The offloading toolchain can handle it) but cannot
use it for the native toolchain which is used for making tests.
This approach is vastly superior in every way, allowing us to treat the
GPU as a standard cross-compiling target. We can now install the GPU
utilities to do things like use the offload tests and other fun things.
Some certain utilities need to be built with
`--target=${LLVM_HOST_TRIPLE}` as well. I think this is a fine
workaround as we
will always assume that the GPU `libc` is a cross-build with a
functioning host.
Depends on https://github.com/llvm/llvm-project/pull/81557
GCC reports an instance of -Warray-bounds in block_offset. Reimplement
block_offset in terms of memcpy_inline which was created to avoid this
diagnostic. See the linked issue for the full trace of diagnostic.
Fixes: https://github.com/llvm/llvm-project/issues/76877
The [standard](https://eel.is/c++draft/expr.add#4.3) forbids forming
pointers to invalid objects even if the pointer is never read from or
written to. This patch makes sure that we don't do pointer arithmetic on
invalid pointers.
Co-authored-by: Vitaly Buka <vitalybuka@google.com>
Software prefetching helps recover performance when hardware prefetching
is disabled. The 'LIBC_COPT_MEMSET_X86_USE_SOFTWARE_PREFETCHING' compile
time option allows users to use this patch.
