This lays the groundwork for #2879. This library will be built and linked when a
static libc is going to be linked into the compilation. Currently, that means
musl, wasi-libc, and MinGW-w64. As a demonstration, this commit removes the musl
C code for a few string functions and implements them in libzigc. This means
that those libzigc functions are now load-bearing for musl and wasi-libc.
Note that if a function has an implementation in compiler-rt already, libzigc
should not implement it. Instead, as we recently did for memcpy/memmove, we
should delete the libc copy and rely on the compiler-rt implementation.
I repurposed the existing "universal libc" code to do this. That code hadn't
seen development beyond basic string functions in years, and was only usable-ish
on freestanding. I think that if we want to seriously pursue the idea of Zig
providing a freestanding libc, we should do so only after defining clear goals
(and non-goals) for it. See also #22240 for a similar case.
Linux kernel syscalls expect to be given the number of bits of sigset that
they're built for, not the full 1024-bit sigsets that glibc supports.
I audited the other syscalls in here that use `sigset_t` and they're all
using `NSIG / 8`.
Fixes#12715
These started failing with LLVM 20 for unclear reasons:
test-std
└─ run test std-mips64-linux.4.19...6.13.4-gnuabi64.2.28-mips64r2-Debug-libc 2798/2878 passed, 2 failed, 78 skipped
error: 'posix.test.test.link with relative paths' failed: expected 2, found 0
/home/alexrp/Source/ziglang/zig-llvm20/lib/std/testing.zig:103:17: 0x1d9e5bf in expectEqualInner__anon_47031 (test)
return error.TestExpectedEqual;
^
/home/alexrp/Source/ziglang/zig-llvm20/lib/std/posix/test.zig:311:9: 0x3650f57 in test.link with relative paths (test)
try testing.expectEqual(@as(@TypeOf(nstat.nlink), 2), nstat.nlink);
^
error: 'posix.test.test.linkat with different directories' failed: expected 2, found 0
/home/alexrp/Source/ziglang/zig-llvm20/lib/std/testing.zig:103:17: 0x1d9e5bf in expectEqualInner__anon_47031 (test)
return error.TestExpectedEqual;
^
/home/alexrp/Source/ziglang/zig-llvm20/lib/std/posix/test.zig:355:9: 0x3653377 in test.linkat with different directories (test)
try testing.expectEqual(@as(@TypeOf(nstat.nlink), 2), nstat.nlink);
^
error: while executing test 'zig.system.darwin.macos.test.detect', the following test command failed:
qemu-mips64 -L /opt/glibc/mips64-linux-gnu-n64 /home/alexrp/Source/ziglang/zig-llvm20/.zig-cache/o/22a8c3762ea56ae3a674fa9ad15f6657/test --seed=0xa1dbb43c --cache-dir=/home/alexrp/Source/ziglang/zig-llvm20/.zig-cache --listen=-
test-std
└─ run test std-mips64-linux.4.19...6.13.4-gnuabi64.2.28-mips64r2-Debug-libc 2798/2878 passed, 1 failed, 79 skipped
error: 'posix.test.test.linkat with different directories' failed: expected 2, found 0
/home/alexrp/Source/ziglang/zig-llvm20/lib/std/testing.zig:103:17: 0x1d9e22f in expectEqualInner__anon_47031 (test)
return error.TestExpectedEqual;
^
/home/alexrp/Source/ziglang/zig-llvm20/lib/std/posix/test.zig:356:9: 0x3650b47 in test.linkat with different directories (test)
try testing.expectEqual(@as(@TypeOf(nstat.nlink), 2), nstat.nlink);
^
error: while executing test 'zig.system.darwin.macos.test.detect', the following test command failed:
qemu-mips64 -L /opt/glibc/mips64-linux-gnu-n64 /home/alexrp/Source/ziglang/zig-llvm20/.zig-cache/o/22a8c3762ea56ae3a674fa9ad15f6657/test --seed=0xa1dbb43c --cache-dir=/home/alexrp/Source/ziglang/zig-llvm20/.zig-cache --listen=-
Unfortunately, neither GDB nor LLDB want to play nice with qemu-mips64(el) at
the moment, so I can't easily debug these failures.
