Clang fails to compile the CBE translation of this code ("non-ASM
statement in naked function"). Similar to the implementations of
`restore_rt` on x86 and ARM, when the CBE is in use, this commit employs
alternative inline assembly that avoids using non-immediate input
operands.
In a library, the two `builtin.link_libc` and `builtin.output_mode ==
.Exe` checks could both be false. Thus, you would get a compile error
even if you specified an `env_map` at runtime. This change turns the
compile error into a runtime panic and updates the documentation to
reflect the runtime requirement.
Fixes#25209.
On PowerPC, some registers are both inputs to syscalls and clobbered by
them. An example is r0, which initially contains the syscall number, but
may be overwritten during execution of the syscall.
musl and glibc use a `+` (read-write) constraint to indicate this, which
isn't supported in Zig. The current implementation of PowerPC syscalls
in the Zig standard library instead lists these registers as both inputs
and clobbers, but this results in the C backend generating code that is
invalid for at least some C compilers, like GCC, which doesn't support
the specifying the same register as both an input and a clobber.
This PR changes the PowerPC syscall functions to list such registers as
inputs and outputs rather than inputs and clobbers. Thanks to jacobly0
who pointed out that it's possible to have multiple outputs; I had
gotten the wrong idea from the documentation.
If the compiler happens to pick `ret = r0`, then this will assemble to
`ag r0, 0` which is obviously not what we want. Using `a` instead of `r` will
ensure that we get an appropriate address register, i.e. `r1` through `r15`.
Re-enable pie_linux for s390x-linux which was disabled in
ed7ff0b693037078f451a7c6c1124611060f4892.
There are two reasons for this:
1. Apple is about to drop support for this target. Zig will keep support
but move it to a lower tier - one that does not require continuous CI
testing. Support for this target will be maintained by the enthusiasm
of contributors but will not block other bug fixes and enhancements.
2. This is our only non-self-hosted action runner. We are migrating away
from GitHub soon at which point this runner will no longer be
available.
