On NetBSD, for backwards compatibility, various libc symbols are
renamed to a symbol with a version suffix. For example, this is the
(abbreviated) definition of sigaction:
int sigaction(...) __asm__ ("__sigaction14")
This poses a challenge for libgo, which attempts to link sigaction by
way of an "//extern" comment:
//extern sigaction
func sigaction(...)
This results in a reference to the deprecated compatibility symbol
"sigaction", rather than the desired "__sigaction14" symbol.
This patch introduces a new "//extern-sysinfo" comment to handle this
situation. The new mklinknames.awk script scans a package for these
comments and outputs a "//go:linkname" directive that links the wrapper
to the correct versioned symbol, as determined by parsing the __asm__
annotation on the function's declaration in gen-sysinfo.go.
For now, only the following packages are scanned by mklinknames.awk:
os
os/user
runtime
syscall
gotools/:
* Makefile.am (check-runtime): Add runtime_linknames.go to
--extrafiles.
* Makefile.in: Regenerate.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/265125
Nikhil Benesch