This moves the LLVM_LIBC_IS_DEFINED macro to its own header is
__support/macros. Its implementation leverages cpp::string_view
instead of rolling its own strcmp; this necessitated fixing
several missing constexpr in the string_view implementation.
The new __support/macros/macro-utils.h is also broken out to hold
the stringification macro and can be used in future for token
pasting shenanigans and other such generic macro machinery.
Summary:
`Status` is unfortunately heavily overloaded in practice. Things like
X11 define it as a macro. Best to just remove that possibility entirely.
Several key targets unconditionally depend on `OSUtil.osutil` target,
causing errors when it is unnecessarily linked, or not available. This
PR fine-tuning the dependency on `OSUtil.osutil` to cleanly decouple
those targets, and gracefully skip targets that need `osutil`. Main
changes include:
* Make `LIBC_COPT_USE_C_ASSERT` to a cmake config, allowing
`LIBC_ASSERT` to use system's `assert` and not depending on `osutil`.
* Adjust cmake dependency for the following targets:
- libc.src.__support.libc_assert
- libc.src.__support.time.*
- libc.src.time.linux.*
- libc.src.unistd.*
- LibcTest
* Give an option for `TestLogger` to use system's `fprintf` instead of
`osutil`.
Some of the functions were missing LIBC_INLINE and some of the variable
names were less descriptive than I liked. This PR fixes both as well as
cleaning up dependencies.
Summary:
Right now the scan checks to avoid the unspecified behavior in
`clzg(0)`. This is used as the source to the shuffle instruction, but
the argument is discarded at zero anyway. So, we simply pass unspecified
behavior to shuffle and then discard it. This should be fine. The scan
routines are expected to be optimal.
Also renames `sum` to `add`.
Add support for the half-precision complementary error function
`erfcf16``, using a Sollya generated polynomial implementation with
proper handling of special cases.
Extend the MPFR utilities with erfc support to allow tests.
closes: #180927
- Switch log1pf to use the same log_eval from inverse hyperbolic
functions.
- Optimize log_eval to use the same range reduction scheme as double
precision log
- Reduce the table size needed for log range reduction.
- This lower the overall latency of log1pf and inverse hyperbolic
functions.
Implement support for flushing all open streams when fflush is called
with a NULL pointer.
* Added a global linked list to track all open File objects.
* Updated File class to include prev/next pointers and list management
methods.
* Implemented POSIX requirement for fflush to sync seekable input
streams back to the host environment.
* Updated Linux-specific file creation to register new files in the
global list.
* Fixed a memory safety bug in create_file_from_fd using delete instead
of free.
* Added unit test for fflush(NULL).
* Added explanatory comments to fflush.cpp and file.cpp.
Moved the declaration of 'ret' inside the SYS_utimes block to prevent an
unused variable warning on the libc-riscv32-qemu-yocto-fullbuild-dbg
builder, which doesn't define SYS_utimes.
With currently only LIBC_INLINE, we just hint the compiler to inline the
function which however in practice is not always the case.
Since we added `[[gnu::always_inline]]` on linux/x86_64 it makes sense
to do it on all platforms consistently and add a comment explaining why
we need it.
Implemented the utimensat syscall for Linux and added the entrypoint to
sys/stat.h.
* Added utimensat syscall wrapper to OSUtil
* Updated utimes to use the utimensat wrapper
* Added utimensat unit tests to sys/stat
* Configured entrypoints for x86_64, riscv, and aarch64
Currently the guards for `totalorderbf16` and `totalordermagbf16` are as
follows:
```
#ifndef LLVM_LIBC_SRC_MATH_TOTALORDERMAGF16_H
#define LLVM_LIBC_SRC_MATH_TOTALORDERMAGF16_H
-
#endif // LLVM_LIBC_SRC_MATH_TOTALORDERMAGF16_H
```
and
```
#ifndef LLVM_LIBC_SRC_MATH_TOTALORDERF16_H
#define LLVM_LIBC_SRC_MATH_TOTALORDERF16_H
-
#endif // LLVM_LIBC_SRC_MATH_TOTALORDERF16_H
```
As we can see these are for F16 and not BF16 .
This Pr intends to fix that with correct guards as `TOTALORDERBF16` and
`TOTALORDERMAGBF16`
This PR intends to fix a small nit caused in
[1c1135b](1c1135b3fc)
```
#endif // LLVM_LIBC_SRC_MATH_ASINIF16_H
```
to
```
#endif // LLVM_LIBC_SRC_MATH_ATANPIF16_H
```
Replace the explicit `if constexpr` branching for big and little
endianness with compile-time calculated shift constants `VAL_SHIFT` and
`NEXT_SHIFT`. This simplifies the logic and reduces code duplication,
relying on the compiler to constant-fold the zero shifts into no-ops.
This PR intends to fix the nit (mostly caused during the refactor in
693a018dcf08e )
- During refactor we move the implementation along with the explanation
comments to header.
```CPP
// This is an algorithm for log(x) in single precision which is correctly
// rounded for all rounding modes, based on the implementation of log(x) from
// the RLIBM project at:
// https://people.cs.rutgers.edu/~sn349/rlibm
// Step 1 - Range reduction:
// For x = 2^m * 1.mant, log(x) = m * log(2) + log(1.m)
// If x is denormal, we normalize it by multiplying x by 2^23 and subtracting
.....
// Symposium on Principles of Programming Languages (POPL-2022), Philadelphia,
// USA, January 16-22, 2022.
// https://people.cs.rutgers.edu/~sn349/papers/rlibmall-popl-2022.pdf
```
Though the explanation comments were copied and moved to header in
d2492c1 . It wasn't deleted from the `cpp` file.
Along with this in the same,
`#include "src/__support/math/logf.h" // Lookup table for (1/f) and
log(f)`
is wrong as it is actually for
`#include "src/__support/math/common_constants.h" // Lookup table for
(1/f) and log(f)`
This PR intends to add/update the following things:
- Add missing doc for CMake for shared_math
- Add missing testing command for shared_math_test
- Nits (e.g., grammar, spaces, missing colons, etc.)
Lay the ground for C++26 `constexpr` math functions:
- Introduce `LIBC_ENABLE_CONSTEXPR` macro switch to specify the desire
of `constexpr`-only code route.
- Introduce `LIBC_HAS_CONSTANT_EVALUATION` to indicate that we are using
`constexpr`-only code in all dependent functions.
- Introduce `LIBC_CONSTEXPR` macro qualifier to aid in altering the
signature of non-`constexpr` functions.
Note that non-`constexpr` qualified functions are caused by the
exploitation of non-`constexpr` compatible utils, resulting in
non-qualified dependent function, but it can be modified to be qualified
using other code routes.
If the function is `constexpr` compatible, then it's prohibited to use
`LIBC_CONSTEXPR` as a function qualifier. We only qualify it with
`constexpr` as usual.
`LIBC_CONSTEXPR` may or may not evaluate to `constexpr` depending on the
environment configurations, thus it's only used to modify the function
signature in constant evaluation context and remove the qualifier if
it's not desired (depending on provided configurations).
Possible side effects:
- Current qualified routes may or may not produce the desired ULP, this
is implementation dependent (function by function basis) and needs
further testing of the chosen code route.
- The shared tests in the current configuration can still compile with
unsupported compiler. I didn't want to raise compilation error with
unsupported compilers now, but we need to push compiler support with
newer versions for this one to work as intended.
This adds LIBC_CONF_PRINTF_MODULAR, which causes floating point support
(later, others) to be weakly linked into the implementation.
__printf_modular becomes the main entry point of the implementaiton, an
printf itself wraps __printf_modular. printf it also contains a
BFD_RELOC_NONE relocation to bring in the float aspect.
See issue #146159 for context.
The `generic_as` function in `dyadic_float.h` had a missing `underflow =
true` at the exact boundary where `unbiased_exp == -EXP_BIAS -
FRACTION_LEN`.
At this boundary, the mantissa MSB maps exactly to the round bit, so
out_mantissa is 0 and the result can only be 0 or min_subnormal. The
value is at most min_subnormal / 2, so it is always tiny and always
inexact `underflow` must be signaled. The < case and the general
subnormal range both already set underflow = true this boundary case was
the only gap.
this specifically fix this error in the erfcf16 function
```
Extracted erfcf16.cpp.o from archive for linking
Running exhaustive check in --rndn mode...
Missing underflow exception for x=0x1.eacp+1 (y=0x1p-24)
```
this fix may also apply to other bfloat16 missing exceptions
(@Sukumarsawant)
part of: #186483
CC: @lntue
