runtime: correctly type interface data.

The backing memory for >1 word interfaces was being scanned
conservatively.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/94000043

diff --git a/src/pkg/runtime/iface.goc b/src/pkg/runtime/iface.goc
index 08da8c7337075c17a8bef375fb2f426fd8cfb406..96bb8b8aa4b26b0fceee10cadd561ac0114b92e4 100644 (file)
--- a/src/pkg/runtime/iface.goc
+++ b/src/pkg/runtime/iface.goc
@@ -161,7 +161,7 @@ copyin(Type *t, void *src, void **dst)
        if(size <= sizeof(*dst))
                alg->copy(size, dst, src);
        else {
-               p = runtime·mal(size);
+               p = runtime·cnew(t);
                alg->copy(size, p, src);
                *dst = p;
        }