See musl commit 05870abeaac0588fb9115cfd11f96880a0af2108
by Rich Felker.
Commit message from musl reproduced here:
fix code path where child function returns in arm __clone built as thumb
mov lr,pc is not a valid way to save the return address in thumb mode
since it omits the thumb bit. use a chain of bl and bx to emulate blx.
this could be avoided by converting to a .S file with preprocessor
conditions to use blx if available, but the time cost here is
dominated by the syscall anyway.
while making this change, also remove the remnants of support for
pre-bx ISA levels. commit 9f290a49bf9ee247d540d3c83875288a7991699c
removed the hack from the parent code paths, but left the unnecessary
code in the child. keeping it would require rewriting two code paths
rather than one, and is useless for reasons described in that commit.
and expand @sqrt
This revealed that the accuracy of ln is not as good as the current algorithm in
musl and glibc, and should be ported again.
v2: actually include tests
v3: fix reversal of in and out arguments on f128M_sqrt()
add test for @sqrt on comptime_float
do not include @nearbyInt() until it works on all targets.
The optimizer will now convert calls to memcmp into a calls to bcmp
in some circumstances. Users who are building freestanding code (not
depending on the platform’s libc) without specifying -ffreestanding may
need to either pass -fno-builtin-bcmp, or provide a bcmp function.
http://llvm.org/docs/ReleaseNotes.html#non-comprehensive-list-of-changes-in-this-release
* introduce wasm32-freestanding-musl .h files to fix
conflicts with stddef.h and errno.h
* fix an issue with zig build system regarding installation of
webassembly libraries
* add implementations to zig's libc:
- strcmp
- strncmp
- strerror
- strlen
See #514
* build-exe does include the startup code that supplies _start for the
wasm32-freestanding target. Previously this did not occur because
of logic excluding "freestanding".
* build-lib for wasm32-freestanding target gets linked by LLD. To avoid
infinite recursion, compiler_rt and zig libc are built as objects
rather than libraries.
- no "lib" prefix and ".wasm" extension instead of ".a". Rather than
build-lib foo.zig producing "libfoo.a", now it produces "foo.wasm".
* go back to using `.o` extension for webassembly objects
* zig libc only provides _start symbol for wasm when linking libc.
* rename std/special/builtin.zig to std/special/c.zig
not to be confused with @import("builtin") which is entirely
different, this is zig's multi-target libc implementation.
* WebAssembly: build-exe is for executables which have a main().
build-lib is for building libraries of functions to use from,
for example, a web browser environment.
- for now pass --export-all for libraries when there are any
C objects because we have no way to detect the list of exports
when compiling C code.
- stop passing --no-entry for executables. if you want --no-entry
then use build-lib.
* make the "musl" ABI the default ABI for wasm32-freestanding.
* zig provides libc for wasm32-freestanding-musl.
