cmd/internal/gc: fix race build (again)

Add OGETG to the list of ignored operations.

We don't instrument the runtime package, but calls to runtime.getg
can appear in other packages, for example, after inlining
runtime.LockOSThread.

Change-Id: I8d6e91f1f3c8fd1302b596bdead42d588c059911
Reviewed-on: https://go-review.googlesource.com/8553
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

diff --git a/src/cmd/internal/gc/racewalk.go b/src/cmd/internal/gc/racewalk.go
index 7ae1c551920da23cdefb2db4a5e899244eb39afd..ec5550171484772f8c989ba2e6902a19eaea6cf2 100644 (file)
--- a/src/cmd/internal/gc/racewalk.go
+++ b/src/cmd/internal/gc/racewalk.go
@@ -410,9 +410,6 @@ func racewalknode(np **Node, init **NodeList, wr int, skip int) {
                OLABEL:
                goto ret
 
-       case OGETG:
-               Yyerror("racewalk: OGETG can happen only in runtime which we don't instrument")
-
                // does not require instrumentation
        case OPRINT, // don't bother instrumenting it
                OPRINTN,     // don't bother instrumenting it
@@ -428,6 +425,11 @@ func racewalknode(np **Node, init **NodeList, wr int, skip int) {
                ONONAME,
                OLITERAL,
                OSLICESTR,
+               // g is goroutine local so cannot race. Although we don't instrument
+               // the runtime package, through inlining the call to runtime.getg can
+               // appear in non runtime packages, for example, after inlining
+               // runtime.LockOSThread.
+               OGETG,
                // always preceded by bounds checking, avoid double instrumentation.
                OTYPESW: // ignored by code generation, do not instrument.
                goto ret