Implement expm1f function that is correctly rounded for all rounding modes. This is based on expf implementation.
From exhaustive testings, using expf implementation, and subtract 1.0 before rounding the final result to single precision
gives correctly rounded results for all |x| > 2^-4 with 1 exception. When |x| < 2^-25, we use x + x^2 (implemented with a
single fma). And for 2^-25 <= |x| <= 2^-4, we use a single degree-8 minimax polynomial generated by Sollya.
Reviewed By: sivachandra, zimmermann6
Differential Revision: https://reviews.llvm.org/D121574
Implement exp2f function that is correctly rounded for all rounding modes.
Reviewed By: sivachandra, zimmermann6
Differential Revision: https://reviews.llvm.org/D121463
Implement expf function that is correctly rounded for all rounding modes.
Reviewed By: sivachandra, zimmermann6
Differential Revision: https://reviews.llvm.org/D121440
The new container is used to store atexit callbacks. This way, we avoid
the possibility of the destructor of the container itself getting added
as an at exit callback.
Reviewed By: abrachet
Differential Revision: https://reviews.llvm.org/D121350
Add initial support for darwin-aarch64 (macOS M1).
Some differences compared to linux-aarch64:
- `math.h` defined `math_errhandling` by the compiler builtin `__math_errhandling()` but Apple Clang 13.0.0 on M1 does not support `__math_errhandling()` builtin as a macro function or a constexpr function.
- `math.h` defines `UNDERFLOW` and `OVERFLOW` macros.
- Besides 5 usual floating point exceptions: `FE_INEXACT`, `FE_UNDERFLOW`, `FE_OVERFLOW`, `FE_DIVBYZERO`, and `FE_INVALID`, `fenv.h` also has another floating point exception: `FE_FLUSHTOZERO`. The corresponding trap for `FE_FLUSHTOZERO` in the control register is at the different location compared to the status register.
- `FE_FLUSHTOZERO` exception flag cannot be raised with the default CPU floating point operation mode.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D120914
There were some "TODO" messages that were for things that I have already
completed. This patch removes those.
Reviewed By: michaelrj
Differential Revision: https://reviews.llvm.org/D121232
Previously, the entire support/CPP folder was in one header library,
which meant that a lot of headers were included where they shouldn't be.
This patch splits each header into its own target, as well as adjusting
each place they were included to only include what is used.
Reviewed By: sivachandra, lntue
Differential Revision: https://reviews.llvm.org/D121237
The loader TLS test for x86_64, which now passes, has been enabled.
A future change should enable the test for aarch64 as well.
Reviewed By: jeffbailey
Differential Revision: https://reviews.llvm.org/D121091
The idea is that, other parts of the libc which require thread/lock
support will be able to use this platform independent setup.
With this change, only the linux implementation of a mutex type has been
moved to the new library. Because of this, there is some duplication
between the new library and src/threads/linux. A follow up change will
move all of src/threads/linux to the new library. The duplication should
be eliminated with that move.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D120795
With modern architectures having a thread pointer and language supporting
thread locals, there is no reason to use a function intermediary to access
the thread local errno value.
The entrypoint corresponding to errno has been replaced with an object
library as there is no formal entrypoint for errno anymore.
Reviewed By: jeffbailey, michaelrj
Differential Revision: https://reviews.llvm.org/D120920
The upstream project ships CMake rules for building vanilla gtest/gmock which conflict with the names chosen by LLVM. Since LLVM's build rules here are quite specific to LLVM, prefixing them to avoid collision is the right thing (i.e. there does not appear to be a path to letting someone *replace* LLVM's googletest with one they bring, so co-existence should be the goal).
This allows LLVM to be included with testing enabled within projects that themselves have a dependency on an official gtest release.
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D120789
New methods to the Atomic class have been added as required. Futex
related types have been consolidated at a common place.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D120705
Add LLVM_LIBC_CLANG_TIDY option and allow LLVM_LIBC_ENABLE_LINTING without full build.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D119180
Only the methods currently required by the libc have been added.
Most of the existing uses of atomic operations have been switched over
to this new class. A future change will clean up the rest of uses.
This change now allows building mutex and condition variable code with a
C++ compiler which does not have stdatomic.h, for example g++.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D120642
__builtin_clz requires just a single instruction on x86 and arm, so this is a performance improvement.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D120579
The benchmark framework synthesizes fake "aggregate" Samples representing mean, median and cv.
We're only interested in "iteration" samples.
Differential Revision: https://reviews.llvm.org/D120062
Often atexit is implemented using __cxa_atexit. I have not implemented __cxa_atexit here because it potentially requires more discussion. It is unique for llvm-libc (I think) that it is an exported symbol that wouldn’t be defined in any spec file because it doesn’t have a header. Implementing it will be trivial given what is here already, but I figured it would be more contentious so it can be implemented later.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D119512
Algorithm for hypotf: compute (a*a + b*b) in double precision, then use Dekker's algorithm to find the rounding error, and then correcting it after taking its square-root.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D118157
The prior page was the proposal doc, this one is now
more about what the project intends to do, written in the
present tense.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D119379
This implements a basic arm64 loader for Linux, and all the currently
enabled linker tests pass. TLS is not implemented, and functions
using it will have undefined behaviour. Notably, the TLS test is
currently disabled on x86_64.
Much of the structure is copied from x86_64 to allow for a refactoring
of the start code between architectures.
Tested:
ninja libc_loader_tests on aarch64-linux.
Co-authored-by: Raman Tenneti <rtenneti@google.com>
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D119641
Previously, building LLVM-libc with GWP ASAN was conditioned on the flag
COMPILER_RT_BUILD_GWP_ASAN, which caused issues do to the default value
of the flag being set in the compiler-rt cmake, which is seperate. Now
GWP ASAN is included based on if it exists as a target, which is more
consistent.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D119789
Simplify the logic when the exponent difference is at least MantissaLength + 2, while still maintaining correct rounding for all rounding modes.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D119843
Add support for getenv as defined by the Open Group's "System Interface &
Header" in https://pubs.opengroup.org/onlinepubs/7908799/xsh/getenv.html
getenv requires a standard way of accessing the environment,
so a pointer to the environment is added to the startup in crt1.
Consquently, this function is not usable on top of other libcs.
Added starts_with method to StringView. getenv function uses it.
Co-authored-by: Jeff Bailey <jeffbailey@google.com>
Reviewed By: sivachandra, rtenneti
Differential Revision: https://reviews.llvm.org/D119403
Siva Chandra Reddy