This patch adds -Werror to LIBGCC2_CFLAGS so that aarch64 can catch
warnings during bootstrap, while not impacting other targets.
The patch also adds -Wno-prio-ctor-dtor to avoid a warning when
compiling lse_init.c
libgcc/
* config/aarch64/t-aarch64: Always use -Werror
-Wno-prio-ctor-dtor.
This is added to enable function multiversioning, but can also be used
directly. The interface is chosen to match that used in LLVM's
compiler-rt, to facilitate cross-compiler compatibility.
The content of the patch is derived almost entirely from Pavel's prior
contributions to compiler-rt/lib/builtins/cpu_model.c. I have made minor
changes to align more closely with GCC coding style, and to exclude any code
from other LLVM contributors, and am adding this to GCC with Pavel's approval.
libgcc/ChangeLog:
* config/aarch64/t-aarch64: Include cpuinfo.c
* config/aarch64/cpuinfo.c: New file
(__init_cpu_features_constructor) New.
(__init_cpu_features_resolver) New.
(__init_cpu_features) New.
Co-authored-by: Pavel Iliin <Pavel.Iliin@arm.com>
The call ABI for SME (Scalable Matrix Extension) requires a number of
helper routines which are added to libgcc so they are tied to the
compiler version instead of the libc version. See
https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#sme-support-routines
The routines are in shared libgcc and static libgcc eh, even though
they are not related to exception handling. This is to avoid linking
a copy of the routines into dynamic linked binaries, because TPIDR2_EL0
block can be extended in the future which is better to handle in a
single place per process.
The support routines have to decide if SME is accessible or not. Linux
tells userspace if SME is accessible via AT_HWCAP2, otherwise a new
__aarch64_sme_accessible symbol was introduced that a libc can define.
Due to libgcc and libc build order, the symbol availability cannot be
checked so for __aarch64_sme_accessible an unistd.h feature test macro
is used while such detection mechanism is not available for __getauxval
so we rely on configure checks based on the target triplet.
Asm helper code is added to make writing the routines easier.
libgcc/ChangeLog:
* config/aarch64/t-aarch64: Add sources to the build.
* config/aarch64/__aarch64_have_sme.c: New file.
* config/aarch64/__arm_sme_state.S: New file.
* config/aarch64/__arm_tpidr2_restore.S: New file.
* config/aarch64/__arm_tpidr2_save.S: New file.
* config/aarch64/__arm_za_disable.S: New file.
* config/aarch64/aarch64-asm.h: New file.
* config/aarch64/libgcc-sme.ver: New file.
