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.
Since https://github.com/llvm/llvm-project/pull/91150, a proxy header
for the errno macros is available and gets included in `libc_errno.h`
since then.
As `libc_errno.cpp` includes `libc_errno.h`, which already includes the
proxy header `hdr/errno_macros.h`, there's no need to include it in
`libc_errno.cpp` if we are in overlay mode, because the proxy header
takes care to either include our header from libc/include/ (fullbuild)
or the corresponding underlying system header (overlay).
This PR:
- Make `clock_gettime` a header-only library
- Add `clock_conversion` header library to allow conversion between
clocks relative to the time of call
- Add `timeout` header library to manage the absolute timeout used in
POSIX's timed locking/waiting APIs
Summary:
GPUs like to execute instructions in the background until something
excplitely consumes them. We are working on adding some
microbenchmarking code, which requires flushing the pending memory
operations beforehand. This patch simply adds these utility functions
that will be used in the near future.
Avoid `cmpxchg` operation if the function has already been called.
The destination operand of `cmpxchg` may receive a write cycle without
regard to the result of the comparison
It was reported from the CORE-MATH project that the `powf`
implementation did not round correctly when `x^y` is either exact for
exactly half-way.
This PR deals with the potential exact cases when `y` is an integer `2 <
y < 25`. In such cases, the results of `x^y` is exactly representable in
double precision.
This PR address issue #89002.
#### Changes in this PR
* Added a simple implementation of `cpp::lock_guard` (an equivalent of
`std::lock_guard`) in libc/src/__support/CPP inspired by the libstdc++
implementation
* Added tests for `cpp::lock_guard` in
/libc/test/src/__support/CPP/mutex_test.cpp
* Replaced all references to `MutexLock` with `cpp::lock_guard`
---------
Co-authored-by: Guillaume Chatelet <gchatelet@google.com>
Summary:
Some targets support denormals as floating point exceptions. This is
provided as an extension in the GNU headers as __FE_DENORM.
This provides it in our headers, however I'm unsure if we should make it
internal or external. I do not think it should be in all exception as it
doesn't represent an exceptional behavior as far as the standard is
concerned, but I'm not an expert.
# Motivation
Futex syscalls are widely used in our codebase as synchronization
mechanism. Hence, it may be worthy to abstract out the most common
routines (wait and wake). On the other hand, C++20 also provides
`std::atomic_notify_one/std::atomic_wait/std::atomic_notify_all` which
align with such functionalities. This PR introduces `Futex` as a subtype
of `cpp::Atomic<FutexWordType>` with additional
`notify_one/notify_all/wait` operations.
Providing such wrappers also make future porting easier. For example,
FreeBSD's `_umtx_op` and Darwin's `ulock` can be wrapped in a similar
manner.
### Similar Examples
1. [bionic
futex](https://android.googlesource.com/platform/bionic/+/refs/heads/main/libc/bionic/bionic_futex.cpp)
2. [futex in Rust's
std](8cef37dbb6/library/std/src/sys/pal/unix/futex.rs (L21))
The test has no control over the CPU state before the test runs.
This test checks whether no exception flags are set, which may not be
true at the start of the test. This used to be not a problem because the
check was broken but that was fixed in ecfb5d9951554d8bdb6a499c958f48cc35f78a88
Adds more FP test macros for the upcoming test adds for #61092 and the
issues opened from it: #88768, #88769, #88770, #88771, #88772.
Fix bug in `{EXPECT,ASSERT}_FP_EXCEPTION`. `EXPECT_FP_EXCEPTION(0)`
seems to be used to test that an exception did not happen, but it always
does `EXPECT_GE(... & 0, 0)` which never fails.
Update and refactor tests that break after the above bug fix. An
interesting way things broke after the above change is that
`ForceRoundingMode` and `quick_get_round()` were raising the inexact
exception, breaking a lot of the `atan*` tests.
The changes for all files other than `FPMatcher.h` and
`libc/test/src/math/smoke/RoundToIntegerTest.h` should have the same
semantics as before. For `RoundToIntegerTest.h`, lines 56-58 before the
changes do not always hold since this test is used for functions with
different exception and errno behavior like `lrint` and `lround`. I've
deleted those lines for now, but tests for those cases should be added
for the different nearest int functions to account for this.
Adding @nickdesaulniers for review.
This PR implements a part of WG14 N2653:
- Define C23 char8_t
- Define C11 char16_t
- Define C11 char32_t
Missing goals are:
- The type of UTF-8 character literals is changed from unsigned char to
char8_t. (Since UTF-8 character literals already have type unsigned
char, this is not a semantic change).
- New mbrtoc8() and c8rtomb() functions declared in <uchar.h> enable
conversions between multibyte characters and UTF-8.
- A new ATOMIC_CHAR8_T_LOCK_FREE macro.
- A new atomic_char8_t typedef name.
Closes#84689.
Adding @lntue for review.
I was curious about the implementation of
`round_using_current_rounding_mode` used for the `nearbyint` functions.
It has one of the rounding modes as unreachable
([here](https://github.com/llvm/llvm-project/blob/main/libc/src/__support/FPUtil/NearestIntegerOperations.h#L243)),
and I was wondering if this was okay for the `nearbyint` functions.
---------
Co-authored-by: Michael Flanders <mkf727@cs.washington.edu>
This adds a new test fixture class FEnvSafeTest (usable as a base
class for other fixtures) that ensures each test doesn't perturb
the `fenv_t` state that the next test will start with. It also
provides types and methods tests can use to explicitly wrap code
under test either to check that it doesn't perturb the state or
to save and restore the state around particular test code.
All the fenv and math tests are updated to use this so that none
can affect another. Expectations that code under test and/or
tests themselves don't perturb state can be added later.
This replaces the old macros LIBC_COPT_TEST_USE_FUCHSIA and
LIBC_COPT_TEST_USE_PIGWEED with LIBC_COPT_TEST_ZXTEST and
LIBC_COPT_TEST_GTEST, respectively. These are really not about
whether the code is in the Fuchsia build or in the Pigweed build,
but just about what test framework is being used. The gtest
framework can be used in many contexts, and the zxtest framework
is not always what's used in the Fuchsia build.
The test/UnitTest/Test.h wrapper header now provides the macro
LIBC_TEST_HAS_MATCHERS() for use in `#if` conditionals on use of
gmock-style matchers, replacing `#if` conditionals that test the
framework selection macros directly.
When building overlay mode with GCC in release mode, glibc's stdlib.h
contains
an extern inline declaration of bsearch. This breaks our use of the
gnu::alias
function attribute in LLVM_LIBC_FUNCTION with GCC because GCC checks
that the
aliasee is defined in the same TU (clang does not).
We're looking at also potentially updating our definition of
LLVM_LIBC_FUNCTION
from libc/src/__support/common.h. Upon testing, I was able to get
-Wnonnull-compare diagnostics from GCC in our definition of bsearch
because
glibc declares bsearch with the fugly nonnull function attribute.
There's more we can do here though to improve our implementation of
bsearch.
7.24.5.1 says:
Pointer arguments on such a call shall still have valid values, as
described in 7.1.4.
We could also use either function attributes or parameter attributes to
denote
these should not be null (for users/callers) and perhaps still check for
non-null explicitly under some yet to be discussed hardening
configurations in
the future.
Link: #60481
Link:
https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-nonnull-function-attribute
