Generate outline atomics if compiling for armv8-a non-LSE AArch64 Linux
(including Android) targets to use LSE instructions, if they are available,
at runtime. Library support is checked by clang driver which doesn't enable
outline atomics if no proper libraries (libgcc >= 9.3.1 or compiler-rt) found.
Differential Revision: https://reviews.llvm.org/D93585
In GCC, `aarch64-*-linux` and `aarch64-*-freebsd` made the switch in 2018
(https://gcc.gnu.org/pipermail/gcc-patches/2018-March/495549.html).
In Clang, FreeBSD/Fuchsia/NetBSD/MinGW aarch64 default to -fasynchronous-unwind-tables.
This patch defaults Generic_GCC aarch64 (which affects Linux) to use -fasynchronous-unwind-tables.
Reviewed By: nickdesaulniers
Differential Revision: https://reviews.llvm.org/D91760
In cooperation with the LLVM patch, this should implement all scalar front-end
parts of the C and C++ ABIs for AArch64.
This patch excludes the NEON support also reviewed due to an outbreak of
batshit insanity in our legal department. That will be committed soon bringing
the changes to precisely what has been approved.
Further reviews would be gratefully received.
llvm-svn: 174055
Pavel Iliin