2 * sparse/check_unused_ret.c
4 * Copyright (C) 2009 Dan Carpenter.
6 * Licensed under the Open Software License version 1.1
11 * This check is supposed to find places like this:
16 * (the first assignment isn't used)
18 * How the check works is that every assignment gets an ID.
19 * We store that assignment ID in a list of assignments that
20 * haven't been used. We also set the state of 'err' from
21 * the example above to be. Then when we use 'err' we remove
22 * it from the list. At the end of the function we print
23 * a list of assignments that still haven't been used.
25 * Note that this check only works for assignments to
26 * EXPR_SYMBOL. Maybe it could be modified to cover other
27 * assignments later but then you would have to deal with
30 * Also this state is quite tied to the order the callbacks
31 * are called in smatch_flow.c. (If the order changed it
39 #include "smatch_slist.h"
48 ALLOCATOR(assignment
, "assignment id");
49 DECLARE_PTR_LIST(assignment_list
, struct assignment
);
50 static struct assignment_list
*assignment_list
;
52 static struct expression
*skip_this
;
55 static struct hsearch_data ignored_funcs
;
56 static const char *kernel_ignored
[] = {
62 static int ignored_function(struct expression
*func
)
66 func
= strip_expr(func
);
67 if (!func
|| func
->type
!= EXPR_CALL
)
70 if (!func
|| func
->type
!= EXPR_SYMBOL
)
73 e
.key
= func
->symbol_name
->name
;
74 hsearch_r(e
, FIND
, &ep
, &ignored_funcs
);
80 static void match_assign_call(struct expression
*expr
)
82 struct expression
*left
;
83 struct assignment
*assign
;
93 if (ignored_function(expr
->right
))
95 left
= strip_expr(expr
->left
);
96 if (!left
|| left
->type
!= EXPR_SYMBOL
)
98 if (left
->symbol
->ctype
.modifiers
& (MOD_TOPLEVEL
| MOD_EXTERN
| MOD_STATIC
))
103 set_state_expr(my_id
, left
, alloc_state_num(assign_id
));
105 assign
= __alloc_assignment(0);
106 assign
->assign_id
= assign_id
++;
107 assign
->name
= get_variable_from_expr(left
, NULL
);
108 assign
->line
= get_lineno();
109 add_ptr_list(&assignment_list
, assign
);
112 static void match_assign(struct expression
*expr
)
114 struct expression
*left
;
118 left
= strip_expr(expr
->left
);
119 if (!left
|| left
->type
!= EXPR_SYMBOL
)
121 delete_state_expr(my_id
, left
);
124 static void delete_used(int assign_id
)
126 struct assignment
*tmp
;
128 FOR_EACH_PTR(assignment_list
, tmp
) {
129 if (tmp
->assign_id
== assign_id
) {
130 DELETE_CURRENT_PTR(tmp
);
133 } END_FOR_EACH_PTR(tmp
);
136 static void delete_used_symbols(struct state_list
*possible
)
138 struct sm_state
*tmp
;
140 FOR_EACH_PTR(possible
, tmp
) {
141 delete_used((int)tmp
->state
->data
);
142 } END_FOR_EACH_PTR(tmp
);
145 static void match_symbol(struct expression
*expr
)
149 expr
= strip_expr(expr
);
150 if (expr
== skip_this
)
152 sm
= get_sm_state_expr(my_id
, expr
);
155 delete_used_symbols(sm
->possible
);
156 delete_state_expr(my_id
, expr
);
159 static void match_end_func(struct symbol
*sym
)
161 struct assignment
*tmp
;
163 FOR_EACH_PTR(assignment_list
, tmp
) {
164 sm_printf("%s +%d %s ", get_filename(), tmp
->line
, get_function());
165 sm_printf("warn: assignment to '%s' was never used\n", tmp
->name
);
166 } END_FOR_EACH_PTR(tmp
);
167 clear_assignment_alloc();
168 __free_ptr_list((struct ptr_list
**)&assignment_list
);
171 void check_unused_ret(int id
)
175 /* It turns out that this test is worthless unless you use --two-passes. */
176 if (!option_two_passes
)
178 add_hook(&match_assign_call
, CALL_ASSIGNMENT_HOOK
);
179 add_hook(&match_assign
, ASSIGNMENT_HOOK
);
180 add_hook(&match_symbol
, SYM_HOOK
);
181 add_hook(&match_end_func
, END_FUNC_HOOK
);
182 hcreate_r(1000, &ignored_funcs
);
183 if (option_project
== PROJ_KERNEL
) {
186 for (i
= 0; i
< ARRAY_SIZE(kernel_ignored
); i
++) {
189 e
.key
= (char *)kernel_ignored
[i
];
191 if (!hsearch_r(e
, ENTER
, &ep
, &ignored_funcs
)) {
192 printf("check_unused_ret.c broke.\n");