Whatever was in the frame pointer register prior to clone() will no longer be
valid in the child process, so zero it to protect FP-based unwinders. This is
just an extension of what was already done for i386 and x86_64. Only applied
to architectures where the _start() code also zeroes the frame pointer.
This was a bit trickier than it should be due to symbol conflicts with
zig's compiler-rt implementation. We attempt to use weak linkage in
our compiler-rt, but this does not seem to be working in all cases. I
manually disabled export of the problematic compiler-rt math functions
in order to cross compile musl's libc.so for all targets as input to
`tools/gen_stubs.zig`.
Other than that, this update went fairly smoothly. Quite a few
additional symbols were added to the blacklist in `tools/gen_stubs.zig`
due to recent reorganization of zig's compiler-rt.
From: Szabolcs Nagy <szabolcs.nagy@arm.com>
armv8 removed the coprocessor instructions other than cp14, so
on an armv8 system the related hwcaps should never be set.
new llvm complains about the use of coprocessor instructions in
armv8-a mode (even though they are never executed at runtime),
so ifdef them out when musl is built for armv8.
<dalias> i think the patch looks ok
also start prefering NtDll API. so far:
* NtQueryInformationFile
* NtClose
adds a performance workaround for windows unicode conversion. but that
should probably be removed before merging
