Previously, we used empty, non-ELF crti.o, crtn.o, libm.a and libc++.a
files. Instead, we now still use dummies but they are real ELF object
files and archives.

A follow up patch will add feof and ferror.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D122327

This patch adds aligned_alloc as an entrypoint. Previously it was being
included implicitly.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D122362

We were previously linking to libllvmlibc.a. But, with libllvmlibc.a now
including functions which depend on the loader, we will have to use the
LLVM libc loader as well. To avoid this, we will link to a special
library which is just a collection of SCUDO allocator entrypoints.

Reviewed By: michaelrj

Differential Revision: https://reviews.llvm.org/D122360

This patch primarily fixes the fenv implementation on Windows, since
Windows uses the MXCSR in place of the x87 status registers for storing
information about the floating point environment. This allows FEnv to
work correctly on Windows, and successfully build.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D121839

All existing loader tests are switched to an integration test added with
the new rule. Also, the getenv test is now enabled as an integration test.

All loader tests have been moved to test/integration. Also, the simple
checker library for the previous loader tests has been moved to a
separate directory of its own.

A follow up change will perform more cleanup of the loader CMake rules
to eliminate now redundent options.

Reviewed By: lntue, michaelrj

Differential Revision: https://reviews.llvm.org/D122266

Reviewed By: jeffbailey, michaelrj

Differential Revision: https://reviews.llvm.org/D122272

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D122284

An unnecessary dep of the getenv function is removed. From the x86_64
loader, a call to __llvm_libc::memcpy is replaced with call to
__llvm_libc::inline_memcpy.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D121976

The platform independent file implementation is not an entrypoint so it
cannot be excluded via the entrypoints.txt file. Hence, we need a
special treatment to exclude it from the build.

Reviewed By: michaelrj

Differential Revision: https://reviews.llvm.org/D121947

Having a separate flag helps in setting up proper flags when
implementing, say the Linux specialization of File.

Along the way, a signature for a function which is to be used to open
files has been added. The implementation of the function is to be
included in platform specializations.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D121889

This is now possible because we have a platform independent abstraction
for mutexes.

Reviewed By: lntue, michaelrj

Differential Revision: https://reviews.llvm.org/D121773

Let exhaustive tests indicate each interval PASSED/FAILED.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D121564

We were in between two styles when this file was initially
checked in.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D121676

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D121656

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

Reviewed By: abrachet

Differential Revision: https://reviews.llvm.org/D121334

Add testing macros for errno and floating point exceptions.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D121235

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

This reverts commit 7cdda6b8.

Differential Revision: https://reviews.llvm.org/D121020

Fix small bugs in aarch64/EFnvImpl.h and simplify feclearexcept_test.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D120997

Remove the redundant header FPUtil/FEnvUtils.h, use FPUtil/FEnvImpl.h header instead.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D120965

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