runtime: introduce and consistently use setNsec for timespec

The general code for setting a timespec value sometimes used set_nsec
and sometimes used a combination of set_sec and set_nsec. Standardize
on a setNsec function that takes a number of nanoseconds and splits
them up to set the tv_sec and tv_nsec fields. Consistently mark
setNsec as go:nosplit, since it has to be that way on some systems
including Darwin and GNU/Linux. Consistently use timediv on 32-bit
systems to help stay within split-stack limits on processors that
don't have a 64-bit division instruction.

Change-Id: I6396bb7ddbef171a96876bdeaf7a1c585a6d725b
Reviewed-on: https://go-review.googlesource.com/c/go/+/167389
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 1 insertions, 4 deletions

diff --git a/src/runtime/os_openbsd.go b/src/runtime/os_openbsd.go
index 353a5d94ba..42fe315bcd 100644
--- a/src/runtime/os_openbsd.go
+++ b/src/runtime/os_openbsd.go
@@ -139,10 +139,7 @@ func semasleep(ns int64) int32 {
 	var tsp *timespec
 	if ns >= 0 {
 		var ts timespec
-		var nsec int32
-		ns += nanotime()
-		ts.set_sec(int64(timediv(ns, 1000000000, &nsec)))
-		ts.set_nsec(nsec)
+		ts.setNsec(ns + nanotime())
 		tsp = &ts
 	}