11f5207b7SJohn Levon /*
21f5207b7SJohn Levon  * Copyright (C) 2009 Dan Carpenter.
31f5207b7SJohn Levon  *
41f5207b7SJohn Levon  * This program is free software; you can redistribute it and/or
51f5207b7SJohn Levon  * modify it under the terms of the GNU General Public License
61f5207b7SJohn Levon  * as published by the Free Software Foundation; either version 2
71f5207b7SJohn Levon  * of the License, or (at your option) any later version.
81f5207b7SJohn Levon  *
91f5207b7SJohn Levon  * This program is distributed in the hope that it will be useful,
101f5207b7SJohn Levon  * but WITHOUT ANY WARRANTY; without even the implied warranty of
121f5207b7SJohn Levon  * GNU General Public License for more details.
131f5207b7SJohn Levon  *
141f5207b7SJohn Levon  * You should have received a copy of the GNU General Public License
151f5207b7SJohn Levon  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
161f5207b7SJohn Levon  */
171f5207b7SJohn Levon 
181f5207b7SJohn Levon #include "smatch.h"
191f5207b7SJohn Levon #include "smatch_extra.h"
201f5207b7SJohn Levon 
211f5207b7SJohn Levon static int my_id;
221f5207b7SJohn Levon 
231f5207b7SJohn Levon STATE(derefed);
241f5207b7SJohn Levon 
underef(struct sm_state * sm,struct expression * mod_expr)251f5207b7SJohn Levon static void underef(struct sm_state *sm, struct expression *mod_expr)
261f5207b7SJohn Levon {
271f5207b7SJohn Levon 	set_state(my_id, sm->name, sm->sym, &undefined);
281f5207b7SJohn Levon }
291f5207b7SJohn Levon 
match_dereference(struct expression * expr)301f5207b7SJohn Levon static void match_dereference(struct expression *expr)
311f5207b7SJohn Levon {
321f5207b7SJohn Levon 	if (__in_fake_assign)
331f5207b7SJohn Levon 		return;
341f5207b7SJohn Levon 
351f5207b7SJohn Levon 	if (expr->type != EXPR_PREOP)
361f5207b7SJohn Levon 		return;
371f5207b7SJohn Levon 	expr = strip_expr(expr->unop);
381f5207b7SJohn Levon 	if (!is_pointer(expr))
391f5207b7SJohn Levon 		return;
401f5207b7SJohn Levon 	if (implied_not_equal(expr, 0))
411f5207b7SJohn Levon 		return;
421f5207b7SJohn Levon 
431f5207b7SJohn Levon 	if (is_impossible_path())
441f5207b7SJohn Levon 		return;
451f5207b7SJohn Levon 
461f5207b7SJohn Levon 	set_state_expr(my_id, expr, &derefed);
471f5207b7SJohn Levon }
481f5207b7SJohn Levon 
set_param_dereferenced(struct expression * call,struct expression * arg,char * key,char * unused)491f5207b7SJohn Levon static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
501f5207b7SJohn Levon {
511f5207b7SJohn Levon 	struct symbol *sym;
521f5207b7SJohn Levon 	char *name;
531f5207b7SJohn Levon 
541f5207b7SJohn Levon 	name = get_variable_from_key(arg, key, &sym);
551f5207b7SJohn Levon 	if (!name || !sym)
561f5207b7SJohn Levon 		goto free;
571f5207b7SJohn Levon 
581f5207b7SJohn Levon 	if (implied_not_equal_name_sym(name, sym, 0))
591f5207b7SJohn Levon 		goto free;
601f5207b7SJohn Levon 	set_state(my_id, name, sym, &derefed);
611f5207b7SJohn Levon 
621f5207b7SJohn Levon free:
631f5207b7SJohn Levon 	free_string(name);
641f5207b7SJohn Levon }
651f5207b7SJohn Levon 
match_condition(struct expression * expr)661f5207b7SJohn Levon static void match_condition(struct expression *expr)
671f5207b7SJohn Levon {
681f5207b7SJohn Levon 	struct sm_state *sm;
69*c85f09ccSJohn Levon 	char *name;
701f5207b7SJohn Levon 
711f5207b7SJohn Levon 	if (__in_pre_condition)
721f5207b7SJohn Levon 		return;
731f5207b7SJohn Levon 
74*c85f09ccSJohn Levon 	name = get_macro_name(expr->pos);
75*c85f09ccSJohn Levon 	if (name &&
76*c85f09ccSJohn Levon 	    (strcmp(name, "likely") != 0 && strcmp(name, "unlikely") != 0))
771f5207b7SJohn Levon 		return;
781f5207b7SJohn Levon 
791f5207b7SJohn Levon 	if (!is_pointer(expr))
801f5207b7SJohn Levon 		return;
811f5207b7SJohn Levon 
821f5207b7SJohn Levon 	sm = get_sm_state_expr(my_id, expr);
831f5207b7SJohn Levon 	if (!sm || sm->state != &derefed)
841f5207b7SJohn Levon 		return;
851f5207b7SJohn Levon 
861f5207b7SJohn Levon 	sm_warning("variable dereferenced before check '%s' (see line %d)", sm->name, sm->line);
871f5207b7SJohn Levon 	set_state_expr(my_id, expr, &undefined);
881f5207b7SJohn Levon }
891f5207b7SJohn Levon 
check_deref_check(int id)901f5207b7SJohn Levon void check_deref_check(int id)
911f5207b7SJohn Levon {
921f5207b7SJohn Levon 	my_id = id;
931f5207b7SJohn Levon 	add_hook(&match_dereference, DEREF_HOOK);
941f5207b7SJohn Levon 	add_hook(&match_condition, CONDITION_HOOK);
951f5207b7SJohn Levon 	select_return_implies_hook(DEREFERENCE, &set_param_dereferenced);
961f5207b7SJohn Levon 	add_modification_hook(my_id, &underef);
971f5207b7SJohn Levon }