runtime: simplify GOOS detection in mstart()

The existing condition is long and repetitive.  Using select/case with
multiple values in the expression list is more concise and clearer.

Change-Id: I43f8abcf958e433468728f1d89ff1436332b29da
Reviewed-on: https://go-review.googlesource.com/c/go/+/188519
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index df9878338557653d973ce63843496dd1428f1507..72e6f0da0c212b3b72d8dfd1b96677b716d6ddee 100644 (file)
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -1167,7 +1167,8 @@ func mstart() {
        mstart1()
 
        // Exit this thread.
-       if GOOS == "windows" || GOOS == "solaris" || GOOS == "illumos" || GOOS == "plan9" || GOOS == "darwin" || GOOS == "aix" {
+       switch GOOS {
+       case "windows", "solaris", "illumos", "plan9", "darwin", "aix":
                // Windows, Solaris, illumos, Darwin, AIX and Plan 9 always system-allocate
                // the stack, but put it in _g_.stack before mstart,
                // so the logic above hasn't set osStack yet.