cmd/compile/internal/gc: allow //go:systemstack only in runtime

Fixes #12454.

Change-Id: I6406b0119bc4d6c3d1e6f1896b588b7d101448a3
Reviewed-on: https://go-review.googlesource.com/14274
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/compile/internal/gc/lex.go b/src/cmd/compile/internal/gc/lex.go
index 3fab3582ed5844ce83c3abd1c1a92aba00fcf788..09a44b28e6bba07f1e6896f93de01d9ab2d5a1ef 100644 (file)
--- a/src/cmd/compile/internal/gc/lex.go
+++ b/src/cmd/compile/internal/gc/lex.go
@@ -1623,6 +1623,9 @@ func getlinepragma() int {
                }
 
                if verb == "go:systemstack" {
+                       if compiling_runtime == 0 {
+                               Yyerror("//go:systemstack only allowed in runtime")
+                       }
                        systemstack = true
                        return c
                }