Use expm1f(x) = exp(x) - 1 for |x| > ln(2).
For |x| <= ln(2), divide it into 3 subintervals: [-ln2, -1/8], [-1/8, 1/8], [1/8, ln2]
and use a degree-6 polynomial approximation generated by Sollya's fpminmax for each interval.
Errors < 1.5 ULPs when we use fma to evaluate the polynomials.
Differential Revision: https://reviews.llvm.org/D101134
They require clang-11 or above for building and hence had to be disabled
as the bots did not have clang-11 or higher. Bots have now been upgraded
so we can enable these functions now.
The implementations use the x86_64 FPU instructions. These instructions
are extremely slow compared to a polynomial based software
implementation. Also, their accuracy falls drastically once the input
goes beyond 2PI. To improve both the speed and accuracy, we will be
taking the following approach going forward:
1. As a follow up to this CL, we will implement a range reduction algorithm
which will expand the accuracy to the entire double precision range.
2. After that, we will replace the HW instructions with a polynomial
implementation to improve the run time.
After step 2, the implementations will be accurate, performant and target
architecture independent.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D102384
Current implementation defines LIBC_TARGET_MACHINE with the use of CMAKE_SYSTEM_PROCESSOR.
Unfortunately CMAKE_SYSTEM_PROCESSOR is OS dependent and can produce different results.
An evidence of this is the various matchers used to detect whether the architecture is x86.
This patch normalizes LIBC_TARGET_MACHINE and renames it LIBC_TARGET_ARCHITECTURE.
I've added many architectures but we may want to limit ourselves to x86 and ARM.
Differential Revision: https://reviews.llvm.org/D101524
[libc] Introduce asctime, asctime_r to LLVM libc
asctime and asctime_r share the same common code. They call asctime_internal
a static inline function.
asctime uses snprintf to return the string representation in a buffer.
It uses the following format (26 characters is the buffer size) as per
7.27.3.1 section in http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2478.pdf.
The buf parameter for asctime_r shall point to a buffer of at least 26 bytes.
snprintf(buf, 26, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",...)
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D99686
The version of clang installed on the buildbot workers is not able to
compile them. However, the version of gcc installed is able to compile
them fine. So, this change disables them until we can find a way to
compile them using clang on the buildbot workers.
The current generic implementation of the fmaf function has been moved
to the FPUtil directory. This allows one use the fma operation from
implementations of other math functions like the trignometric functions
without depending on/requiring the fma/fmaf/fmal function targets. If
this pattern ends being convenient, we will switch all generic math
implementations to this pattern.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D100811
gmtime and gmtime_r share the same common code. They call gmtime_internal
a static inline function. Thus added only validation tests for gmtime_r.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D99046
This change doesn't handle TIMEZONE, tm_isdst and leap seconds.
Moved shared code between mktime and gmtime into time_utils.cpp.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D98467
This option will build LLVM libc as a full libc by itself. In this mode,
it is not expected that it will be mixed with other libcs. The
non-full-build mode will be the default LLVM libc build mode. In a future
where LLVM libc is complete enough, the full libc build will be made the
default mode.
Namely, implementations of fegetexceptfflag, fesetexceptflag,
fegetenv, fesetenv, feholdexcept and feupdateenv have been added.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D96935
Namely, these are the functions enabled: rint*, lrint*, llrint*, lround*,
llround*, nearbyint*. They were previously not enabled because they
required rounding mode and FP exception support. Now that rounding mode
and FP exception support is available for Aarch64, they can be enabled.
This change does not try to move the common parts of x86 and aarch64 and
build few abstractions over them. While this is possible, x86 story
needs a bit of cleanup, especially around manipulation of the mxcsr
register. Moreover, on x86 one can raise exceptions without performing
exception raising operations. So, all of this can be done in follow up
patches.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D94947
Use `memcpy` rather than copying bytes one by one, for there might be large
size structs to move.
Reviewed By: gchatelet, sivachandra
Differential Revision: https://reviews.llvm.org/D93195
A differential fuzzer for these functions has also been added.
Along the way, a small correction has been done to the normal/subnormal
limits of x86 long double values.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D94109
The implementation is exactly the same as rint* as even rint does not
raise any floating point exceptions currently. [Note that the standards
do not specify that floating point exceptions must be raised - they
leave it up to the implementation to choose to raise FE_INEXACT when
rounding non-integral values.]
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D94112
A new function to MPFRWrapper has been added, which is used to set up
the unit tests.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D93007
Refactor src/math/hypotf.cpp and test/src/math/hypotf_test.cpp and reuse them for hypot and hypot_test
Differential Revision: https://reviews.llvm.org/D91831
This introduces mktime to LLVM libc, based on C99/C2X/Single Unix Spec.
Co-authored-by: Jeff Bailey <jeffbailey@google.com>
This change doesn't handle TIMEZONE, tm_isdst and leap seconds. It returns -1 for invalid dates. I have verified the return results for all the possible dates with glibc's mktime.
TODO:
+ Handle leap seconds.
+ Handle out of range time and date values that don't overflow or underflow.
+ Implement the following suggestion Siva - As we start accumulating the seconds, we should be able to check if the next amount of seconds to be added can lead to an overflow. If it does, return the overflow value. If not keep accumulating. The benefit is that, we don't have to validate every input, and also do not need the special cases for sizeof(time_t) == 4.
+ Handle timezone and update of tm_isdst
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D91551
The rounding behavior of NormalFloat to float format has been changed
to round to nearest. Also, a bug in NormalFloat to subnormal number
conversion has been fixed.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D91591
The function listings in api.td are removed. The same lists are now deduced using the information
in entrypoints.txt.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D89267
The implementation is not fully standards compliant in the sense that
errno is not set on error, and floating point exceptions are not raised.
Subnormal range and normal range are tested separately in the tests.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D86666
The new code added is still very x86_64 specific. AArch64 support will
be added very soon and refactoring of the loader code will be done as
part of the patches adding it.
Reviewed By: asteinhauser
Differential Revision: https://reviews.llvm.org/D82700
Current implementations of single precision and double precision
floating point operations operate on bits of the integer type of
same size. The code made use of magic masks which were listed as
literal integer values. This is not possible in the case of long
double type as the mantissa of quad-precision long double type used
on non-x86 architectures is wider that the widest integer type for
which we can list literal values. So, in this patch, to avoid
using magic masks specified with literal values, we use packed
bit-field struct types and let the compiler generate the masks.
This new scheme allows us to implement long double flavors of the
various floating point operations. To keep the size of the patch
small, only the implementations of fabs and trunc have been
switched to the new scheme. In following patches, all exisiting
implementations will be switched to the new scheme.
Reviewers: asteinhauser
Differential Revision: https://reviews.llvm.org/D82036
Implementations of copysign[f], frexp[f], logb[f], and modf[f] are added.
Reviewers: asteinhauser
Differential Revision: https://reviews.llvm.org/D81134
Summary:
With this change, "ninja check-libc" on linux/aarch64 succeeds.
However, all entrypoints with machine dependent implementations
have been skipped. A good number of these skipped entrypoints can
be enabled once we have aarch64 syscall support available.
Reviewers: abrachet, asteinhauser
Differential Revision: https://reviews.llvm.org/D81533
Conditionally adding subdirectories was missed in a few places previously.
This change adds the conditionals. A sub-directory was being added
needlessly in another place. That has been removed.
Summary:
If a test depends on a skipped entrypoint, then the test is also
skipped. This setup will be useful as we gradually add support for
more operating systems and target architectures.
Reviewers: asteinhauser
Differential Revision: https://reviews.llvm.org/D81489
Summary:
This patch aims to add integration tests to check the following:
1) Header files are generated as expected.
2) Libc functions have the correct public name.
3) Libc functions have the correct return type and parameter types.
4) Symbols are exposed in the public lib.a files.
Reviewers: sivachandra, abrachet
Reviewed By: sivachandra
Subscribers: aheejin, ecnelises, dxf, mgorny, jfb, tschuett, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D79192
This change does not handle any extensions. Only the C standard
variations are handled.
Reviewers: abrachet
Differential Revision: https://reviews.llvm.org/D79150
Summary: Adds `write` for Linux and FDReader utility which should be useful for some stdio tests as well.
Reviewers: sivachandra, PaulkaToast
Reviewed By: sivachandra
Subscribers: mgorny, tschuett, libc-commits
Differential Revision: https://reviews.llvm.org/D78184
NFC intended in the implementaton. Only mechanical changes to fit the LLVM
libc implementation standard have been done.
Math testing infrastructure has been added. This infrastructure compares the
results produced by the libc with the high precision results from MPFR.
Tests making use of this infrastructure have been added for cosf, sinf and
sincosf.
Reviewers: abrachet, phosek
Differential Revision: https://reviews.llvm.org/D76825
Summary:
This patch adds a very basic `FILE` type and basic `fwrite`.
It also removes `snprintf` from `StdIO`'s function spec because `VarArgType` was causing the generation to fail.
Reviewers: sivachandra, PaulkaToast
Reviewed By: sivachandra
Subscribers: mgorny, MaskRay, tschuett, libc-commits
Differential Revision: https://reviews.llvm.org/D77626
Only targets setup by the special LLVM libc rules now have fully
qualified names. The naming style is similar to fully qualified names in
Python.
Reviewers: abrachet, PaulkaToast, phosek
Differential Revision: https://reviews.llvm.org/D77340
Summary:
Made all header files consistent based of this documentation: https://llvm.org/docs/CodingStandards.html#file-headers.
And did the same for all source files top of file comments.
Reviewers: sivachandra, abrachet
Reviewed By: sivachandra, abrachet
Subscribers: MaskRay, tschuett, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D77533
Summary:
This patch adds a Linux implementation for `signal`
It also fixes `ASSERT|EXPECT_THAT` macros
Reviewers: sivachandra, PaulkaToast, MaskRay
Reviewed By: sivachandra
Subscribers: mgorny, tschuett, libc-commits
Differential Revision: https://reviews.llvm.org/D76536
Summary: This patch adds a temporary `__assert_fail` and `assert` definition to make it available to internal llvm libc code. `__assert_fail` writes to fd 2 directly instead of `stderr`, using SYS_write. I have not put it in its own linux directory because this is temporary and it should be using stdio's api in the future. It does not currently print out the line number (although we could do that by stringifying `__LINE__` if reviewers wish).
Reviewers: sivachandra, gchatelet, PaulkaToast
Reviewed By: sivachandra
Subscribers: mgorny, MaskRay, tschuett, libc-commits
Differential Revision: https://reviews.llvm.org/D75420
These functions only support locking and unlocking of plain mutexes.
They will be extended in future changes to handled recursive and timed
mutexes.
Reviewers: phosek
Differential Revision: https://reviews.llvm.org/D74653
The following are the differences from the first version:
1. The kernel does not copy the stack for the new thread (it cannot).
The previous version missed this fact. In this new version, the new
thread's start args are copied on to the new stack in a known location
so that the new thread can sniff them out.
2. A start args sniffer for x86_64 has been added.
2. Default stack size has been increased to 64KB.
Reviewers: abrachet, phosek
Differential Revision: https://reviews.llvm.org/D75818
A target to generate the std C threads.h file has been added. This
utilizes the new feature added in this change.
Reviewers: phosek
Differential Revision: https://reviews.llvm.org/D75379
Summary:
This patch adds signal support on Linux. The current implementation gets the SIG* macros and types like `sigset_t` from <linux/signals.h>
This patch also adds raise(3), and internal routines `block_all_signals` and `restore_signals`
Reviewers: sivachandra, MaskRay, gchatelet
Reviewed By: sivachandra
Subscribers: libc-commits, mgorny, tschuett
Differential Revision: https://reviews.llvm.org/D74528
Summary: This patch adds a convenience template function so we don't need to cast all types to `long` manually when calling `__llvm_libc::syscall`.
Reviewers: sivachandra, MaskRay, gchatelet
Reviewed By: sivachandra
Subscribers: libc-commits, tschuett
Differential Revision: https://reviews.llvm.org/D74530
This allows us to get rid of the PAGE_SIZE macro and use EXEC_PAGESIZE
from linux/param.h.
Few other points about this change:
1. The linux syscall functions have been moved into a linux specific area
instead of src/unistd/syscall.h. The Linux syscall function from unistd.h
is a public vararg function. What we have currently are linux speciif internal
overloaded C++ functions. So, moving them to a Linux only area is more
meaningful.
2. The implementations of mmap and munmap are now in a 'linux' directory
within src/sys/mman. The idea here is that platform specific
implementations will live in a platform specific subdirectories like these.
Infrastructure common to a platform will live in the platform's config
directory. For example, the linux syscall implementations live in
config/linux.
Reviewers: abrachet
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D73302
Summary:
Some syscalls like SYS_clone do not tolerate a return instruction after
the syscall instruction. Marking the syscall functions with the
`always_inline` attribute accommodates such syscalls as inlining
eliminates the return instruction.
Reviewers: abrachet, phosek
Subscribers: MaskRay, tschuett, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D72102
A toplevel target, `check-libc` has also been added.
Reviewers: abrachet, phosek
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D72177
Summary:
A set of of linux x86_64 internal syscall helpers have also been added.
This change does not try to be perfect with respect to OS and machine
abstractions. A TODO note has been added at places where such abstractions
would help and make the arrangement scalable and cleaner. Addressing the
TODOs and building such abstractions is not in the scope of this change.
It is hoped that follow up changes cleaning up the problem areas and
addressing the TODOs will better illustrate the need for the changes.
This change also does not try to imitate mmap and munmap implementations
of other libcs. The idea here is to put in the bare minimum required to
obtain a working mmap and munmap, and then add the rest of the
functionality on an as needed basis.
Reviewers: abrachet, phosek, stanshebs, theraven
Subscribers: mgorny, MaskRay, jfb, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D71634
Summary:
* The Python header generator has been removed.
* Docs giving a highlevel overview of the header gen scheme have been
added.
Reviewers: phosek, abrachet
Subscribers: mgorny, MaskRay, tschuett, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D70197
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