runtime: implement darwin raise with pthread_self and pthread_kill

Convert raise from raw syscalls to using the system pthread library.
As a bonus, raise will now target the current thread instead of the
process.

Updates #17490

Change-Id: I2e44f2000bf870e99a5b4dc5ff5e0799fba91bde
Reviewed-on: https://go-review.googlesource.com/110475
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/runtime/os_darwin.go b/src/runtime/os_darwin.go
index 067b7debfa..613725115d 100644
--- a/src/runtime/os_darwin.go
+++ b/src/runtime/os_darwin.go
@@ -540,7 +540,12 @@ func sigtramp(fn uintptr, infostyle, sig uint32, info *siginfo, ctx unsafe.Point
 //go:noescape
 func setitimer(mode int32, new, old *itimerval)
 
-func raise(sig uint32)
+//go:nosplit
+func raise(sig uint32) {
+	tid := pthread_self()
+	pthread_kill(tid, int(sig))
+}
+
 func raiseproc(sig uint32)
 
 //extern SigTabTT runtime·sigtab[];