runtime: fix instrumentation of slice append for race detection

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/6819107

diff --git a/src/pkg/runtime/slice.c b/src/pkg/runtime/slice.c
index 3ec44b875f787ded1917a2dad174bce83c0522a8..2f62c4c02d5208164d186988e87c815af8f29e32 100644 (file)
--- a/src/pkg/runtime/slice.c
+++ b/src/pkg/runtime/slice.c
@@ -86,6 +86,8 @@ runtime·appendslice(SliceType *t, Slice x, Slice y, Slice ret)
                        runtime·racereadpc(x.array + i*t->elem->size, pc);
                for(i=x.len; i<x.cap; i++)
                        runtime·racewritepc(x.array + i*t->elem->size, pc);
+               for(i=0; i<y.len; i++)
+                       runtime·racereadpc(y.array + i*t->elem->size, pc);
        }
 
        if(m > x.cap)