From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 23 Nov 2012 11:25:36 +0000 (+0300)
Subject: extra: clear hard max if we are falling back to the type max on loops
X-Git-Tag: 1.57~160
X-Git-Url: https://repo.or.cz/w/smatch.git/commitdiff_plain/9152d6aac439aebe6cc63b7ac87a2f2016f74ad5

extra: clear hard max if we are falling back to the type max on loops

The problem here is like this:
	if (i = 0; i < some_var; i++) {
		...
	}

If we don't know the value of some_var then the inside the loop the value
is type_max - 1.  The false path is type_max.

The problem is that type_max is just a single value, and we single values
are automatically a hard max.  Which normally works, but in this case we
need to clear the hard max setting.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---

diff --git a/smatch_extra.c b/smatch_extra.c
index 50c3c118..ae3f8bbe 100644
--- a/smatch_extra.c
+++ b/smatch_extra.c
@@ -352,6 +352,7 @@ void __extra_pre_loop_hook_after(struct sm_state *sm,
 {
 	struct expression *iter_expr;
 	sval_t limit;
+	struct smatch_state *state;
 
 	if (!iterator) {
 		while_count_down_after(sm, condition);
@@ -369,7 +370,10 @@ void __extra_pre_loop_hook_after(struct sm_state *sm,
 		limit = sval_binop(estate_min(sm->state), '-',
 				   sval_type_val(estate_type(sm->state), 1));
 	}
-	set_extra_mod(sm->name, sm->sym, alloc_estate(limit));
+	state = alloc_estate(limit);
+	if (!estate_has_hard_max(sm->state))
+		estate_clear_hard_max(state);
+	set_extra_mod(sm->name, sm->sym, state);
 }
 
 static struct smatch_state *unmatched_state(struct sm_state *sm)