dereferences_param: re-write simpler

This takes advantage of the add_dereference_hook() now so a lot of code can be deleted. Signed-off-by: Dan Carpenter <[email protected]>
illumos · May 8, 2023 · 4ce3816 · 4ce3816
1 parent f53e8d2
commit 4ce3816
Showing 1 changed file with 20 additions and 145 deletions.
diff --git a/check_dereferences_param.c b/check_dereferences_param.c
@@ -28,140 +28,6 @@
 static int my_id;
 
 STATE(derefed);
-STATE(ignore);
-STATE(param);
-
-static void pre_merge_hook(struct sm_state *cur, struct sm_state *other)
-{
-	if (cur->state == &derefed || other->state != &derefed)
-		return;
-	if (is_impossible_path())
-		set_state(my_id, cur->name, cur->sym, &derefed);
-}
-
-static void set_ignore(struct sm_state *sm, struct expression *mod_expr)
-{
-	if (sm->state == &derefed)
-		return;
-	set_state(my_id, sm->name, sm->sym, &ignore);
-}
-
-static void match_function_def(struct symbol *sym)
-{
-	struct symbol *arg;
-	int i;
-
-	i = -1;
-	FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
-		i++;
-		if (!arg->ident)
-			continue;
-		set_state(my_id, arg->ident->name, arg, &param);
-	} END_FOR_EACH_PTR(arg);
-}
-
-static int is_ignored_param(struct expression *expr)
-{
-	struct sm_state *sm;
-
-	if (param_was_set(expr))
-		return 1;
-
-	sm = get_sm_state_expr(my_id, expr);
-	if (sm && slist_has_state(sm->possible, &ignore))
-		return 1;
-	return 0;
-}
-
-static void check_deref(struct expression *expr)
-{
-	struct expression *tmp;
-
-	if (is_impossible_path())
-		return;
-
-	tmp = get_assigned_expr(expr);
-	if (tmp)
-		expr = tmp;
-
-	if (expr->type == EXPR_PREOP &&
-	    expr->op == '&') {
-		expr = strip_expr(expr->unop);
-		if (expr->type != EXPR_DEREF)
-			return;
-		expr = strip_expr(expr->deref);
-		if (expr->type != EXPR_PREOP ||
-		    expr->op != '*')
-			return;
-		expr = strip_expr(expr->unop);
-	}
-
-	expr = strip_expr(expr);
-	if (!expr)
-		return;
-
-	if (expr->type == EXPR_PREOP && expr->op == '&')
-		return;
-
-	if (get_param_num(expr) < 0)
-		return;
-
-	if (is_ignored_param(expr))
-		return;
-
-	if (param_was_set(expr))
-		return;
-
-	/*
-	 * At this point we really only care about potential NULL dereferences.
-	 * Potentially in the future we will care about everything.
-	 */
-	if (implied_not_equal(expr, 0))
-		return;
-
-	set_state_expr(my_id, expr, &derefed);
-}
-
-static void match_dereference(struct expression *expr)
-{
-	if (expr->type != EXPR_PREOP)
-		return;
-	check_deref(expr->unop);
-}
-
-static void find_inner_dereferences(struct expression *expr)
-{
-	while (expr->type == EXPR_PREOP) {
-		if (expr->op == '*')
-			check_deref(expr->unop);
-		expr = strip_expr(expr->unop);
-	}
-}
-
-static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
-{
-	struct symbol *sym;
-	char *name;
-
-	check_deref(arg);
-
-	name = get_variable_from_key(arg, key, &sym);
-	if (!name || !sym)
-		goto free;
-	if (name[0] == '&')
-		goto free;
-	if (is_ignored_param(symbol_expression(sym)))
-		goto free;
-	if (get_param_num_from_sym(sym) < 0)
-		goto free;
-	if (param_was_set_var_sym(name, sym))
-		goto free;
-
-	set_state(my_id, name, sym, &derefed);
-	find_inner_dereferences(arg);
-free:
-	free_string(name);
-}
 
 static void process_states(void)
 {
@@ -182,24 +48,33 @@ static void process_states(void)
 	} END_FOR_EACH_SM(tmp);
 }
 
-static void match_pointer_as_array(struct expression *expr)
+static void deref_hook(struct expression *expr)
 {
-	if (!is_array(expr))
+	char *param_name = NULL;
+	struct symbol *sym, *param_sym;
+	char *name;
+
+	name = expr_to_var_sym(expr, &sym);
+	if (!name)
 		return;
-	check_deref(get_array_base(expr));
+
+	param_name = get_param_var_sym_var_sym(name, sym, NULL, &param_sym);
+	if (!param_name || !param_sym)
+		goto free;
+	if (get_param_num_from_sym(param_sym) < 0)
+		goto free;
+	if (param_was_set_var_sym(param_name, param_sym))
+		goto free;
+
+	set_state(my_id, param_name, param_sym, &derefed);
+free:
+	free_string(name);
 }
 
 void check_dereferences_param(int id)
 {
 	my_id = id;
 
-	add_hook(&match_function_def, FUNC_DEF_HOOK);
-
-	add_hook(&match_dereference, DEREF_HOOK);
-	add_hook(&match_pointer_as_array, OP_HOOK);
-	select_return_implies_hook(DEREFERENCE, &set_param_dereferenced);
-	add_modification_hook(my_id, &set_ignore);
-	add_pre_merge_hook(my_id, &pre_merge_hook);
-
+	add_dereference_hook(deref_hook);
 	all_return_states_hook(&process_states);
 }