gc: walk pointer in range on slice/array

R=ken2
https://golang.org/cl/166071

diff --git a/src/cmd/gc/range.c b/src/cmd/gc/range.c
index 4147e8e6c9add1598598434cfd1c2469b7067af1..2794504d2c013a93d9d1999f7807609c91ac6d4e 100644 (file)
--- a/src/cmd/gc/range.c
+++ b/src/cmd/gc/range.c
@@ -90,6 +90,7 @@ walkrange(Node *n)
 {
        Node *ohv1, *hv1, *hv2; // hidden (old) val 1, 2
        Node *ha, *hit; // hidden aggregate, iterator
+       Node *hn, *hp;  // hidden len, pointer
        Node *a, *v1, *v2;      // not hidden aggregate, val 1, 2
        Node *fn, *tmp;
        NodeList *body, *init;
@@ -122,16 +123,32 @@ walkrange(Node *n)
        case TARRAY:
                hv1 = nod(OXXX, N, n);
                tempname(hv1, types[TINT]);
+               hn = nod(OXXX, N, N);
+               tempname(hn, types[TINT]);
+               hp = nil;
 
                init = list(init, nod(OAS, hv1, N));
-               n->ntest = nod(OLT, hv1, nod(OLEN, ha, N));
+               init = list(init, nod(OAS, hn, nod(OLEN, ha, N)));
+               if(v2) {
+                       hp = nod(OXXX, N, N);
+                       tempname(hp, ptrto(a->type->type));
+                       tmp = nod(OINDEX, ha, nodintconst(0));
+                       tmp->etype = 1; // no bounds check
+                       init = list(init, nod(OAS, hp, nod(OADDR, tmp, N)));
+               }
+
+               n->ntest = nod(OLT, hv1, hn);
                n->nincr = nod(OASOP, hv1, nodintconst(1));
                n->nincr->etype = OADD;
                body = list1(nod(OAS, v1, hv1));
                if(v2) {
-                       tmp = nod(OINDEX, ha, hv1);
-                       tmp->etype = 1; // no bounds check
-                       body = list(body, nod(OAS, v2, tmp));
+                       body = list(body, nod(OAS, v2, nod(OIND, hp, N)));
+                       tmp = nod(OADD, hp, nodintconst(t->type->width));
+                       tmp->type = hp->type;
+                       tmp->typecheck = 1;
+                       tmp->right->type = types[tptr];
+                       tmp->right->typecheck = 1;
+                       body = list(body, nod(OAS, hp, tmp));
                }
                break;