qbe

commit 2ec355df6adc457303fcf2076b559fefd80ee593
parent 7ee9970b32a07a62c625c6ae048366ed0c0b0ce4
Author: Quentin Carbonneaux <quentin@c9x.me>
Date:   Mon, 12 Dec 2022 16:55:03 +0100

crash loads from uninitialized slots

Diffstat:
M
mem.c
 | 
11
+++++++++--

1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/mem.c b/mem.c
@@ -304,12 +304,19 @@ coalesce(Fn *fn)
 		for (u=t->use; u<&t->use[t->nuse]; u++) {
 			assert(u->type == UIns);
 			i = u->u.ins;
-			if (!req(i->to, R)) {
+			/* make loads crash */
+			if (isload(i->op))
+				i->arg[0] = CON_Z;
+			else if (i->op == Oargc)
+				i->arg[1] = CON_Z;
+			else if (!req(i->to, R)) {
 				assert(rtype(i->to) == RTmp);
 				vgrow(&stk, ++n);
 				stk[n-1] = i->to.val;
-			} else
+			} else {
+				assert(!isarg(i->op));
 				*i = (Ins){.op = Onop};
+			}
 		}
 	}
 	vfree(stk);