Imported Upstream version 1.4upstream/1.4

1 files changed, 24 insertions, 2 deletions

diff --git a/src/cmd/gc/racewalk.c b/src/cmd/gc/racewalk.c
index 285bd78a2..c9e27fe56 100644
--- a/src/cmd/gc/racewalk.c
+++ b/src/cmd/gc/racewalk.c
@@ -208,6 +208,26 @@ racewalknode(Node **np, NodeList **init, int wr, int skip)
 		goto ret;
 
 	case OCALLFUNC:
+		// Instrument dst argument of runtime.writebarrier* calls
+		// as we do not instrument runtime code.
+		if(n->left->sym != S && n->left->sym->pkg == runtimepkg && strncmp(n->left->sym->name, "writebarrier", 12) == 0) {
+			// Find the dst argument.
+			// The list can be reordered, so it's not necessary just the first or the second element.
+			for(l = n->list; l; l = l->next) {
+				if(strcmp(n->left->sym->name, "writebarrierfat") == 0) {
+					if(l->n->left->xoffset == widthptr)
+						break;
+				} else {
+					if(l->n->left->xoffset == 0)
+						break;
+				}
+			}
+			if(l == nil)
+				fatal("racewalk: writebarrier no arg");
+			if(l->n->right->op != OADDR)
+				fatal("racewalk: writebarrier bad arg");
+			callinstr(&l->n->right->left, init, 1, 0);
+		}
 		racewalknode(&n->left, init, 0, 0);
 		goto ret;
 
@@ -419,8 +439,10 @@ racewalknode(Node **np, NodeList **init, int wr, int skip)
 ret:
 	if(n->op != OBLOCK)  // OBLOCK is handled above in a special way.
 		racewalklist(n->list, init);
-	racewalknode(&n->ntest, &n->ntest->ninit, 0, 0);
-	racewalknode(&n->nincr, &n->nincr->ninit, 0, 0);
+	if(n->ntest != N)
+		racewalknode(&n->ntest, &n->ntest->ninit, 0, 0);
+	if(n->nincr != N)
+		racewalknode(&n->nincr, &n->nincr->ninit, 0, 0);
 	racewalklist(n->nbody, nil);
 	racewalklist(n->nelse, nil);
 	racewalklist(n->rlist, nil);