1// SPDX-License-Identifier: GPL-2.0-only
2/// Compare pointer-typed values to NULL rather than 0
3///
4//# This makes an effort to choose between !x and x == NULL.  !x is used
5//# if it has previously been used with the function used to initialize x.
6//# This relies on type information.  More type information can be obtained
7//# using the option -all_includes and the option -I to specify an
8//# include path.
9//
10// Confidence: High
11// Copyright: (C) 2012 Julia Lawall, INRIA/LIP6.
12// Copyright: (C) 2012 Gilles Muller, INRIA/LiP6.
13// URL: http://coccinelle.lip6.fr/
14// Requires: 1.0.0
15// Options:
16
17virtual patch
18virtual context
19virtual org
20virtual report
21
22@initialize:ocaml@
23@@
24let negtable = Hashtbl.create 101
25
26@depends on patch@
27expression *E;
28identifier f;
29@@
30
31(
32  (E = f(...)) ==
33- 0
34+ NULL
35|
36  (E = f(...)) !=
37- 0
38+ NULL
39|
40- 0
41+ NULL
42  == (E = f(...))
43|
44- 0
45+ NULL
46  != (E = f(...))
47)
48
49
50@t1 depends on !patch@
51expression *E;
52identifier f;
53position p;
54@@
55
56(
57  (E = f(...)) ==
58* 0@p
59|
60  (E = f(...)) !=
61* 0@p
62|
63* 0@p
64  == (E = f(...))
65|
66* 0@p
67  != (E = f(...))
68)
69
70@script:python depends on org@
71p << t1.p;
72@@
73
74coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0")
75
76@script:python depends on report@
77p << t1.p;
78@@
79
80coccilib.report.print_report(p[0], "WARNING comparing pointer to 0")
81
82// Tests of returned values
83
84@s@
85identifier f;
86expression E,E1;
87@@
88
89 E = f(...)
90 ... when != E = E1
91 !E
92
93@script:ocaml depends on s@
94f << s.f;
95@@
96
97try let _ = Hashtbl.find negtable f in ()
98with Not_found -> Hashtbl.add negtable f ()
99
100@ r disable is_zero,isnt_zero exists @
101expression *E;
102identifier f;
103@@
104
105E = f(...)
106...
107(E == 0
108|E != 0
109|0 == E
110|0 != E
111)
112
113@script:ocaml@
114f << r.f;
115@@
116
117try let _ = Hashtbl.find negtable f in ()
118with Not_found -> include_match false
119
120// This rule may lead to inconsistent path problems, if E is defined in two
121// places
122@ depends on patch disable is_zero,isnt_zero @
123expression *E;
124expression E1;
125identifier r.f;
126@@
127
128E = f(...)
129<...
130(
131- E == 0
132+ !E
133|
134- E != 0
135+ E
136|
137- 0 == E
138+ !E
139|
140- 0 != E
141+ E
142)
143...>
144?E = E1
145
146@t2 depends on !patch disable is_zero,isnt_zero @
147expression *E;
148expression E1;
149identifier r.f;
150position p1;
151position p2;
152@@
153
154E = f(...)
155<...
156(
157* E == 0@p1
158|
159* E != 0@p2
160|
161* 0@p1 == E
162|
163* 0@p1 != E
164)
165...>
166?E = E1
167
168@script:python depends on org@
169p << t2.p1;
170@@
171
172coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0, suggest !E")
173
174@script:python depends on org@
175p << t2.p2;
176@@
177
178coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0")
179
180@script:python depends on report@
181p << t2.p1;
182@@
183
184coccilib.report.print_report(p[0], "WARNING comparing pointer to 0, suggest !E")
185
186@script:python depends on report@
187p << t2.p2;
188@@
189
190coccilib.report.print_report(p[0], "WARNING comparing pointer to 0")
191
192@ depends on patch disable is_zero,isnt_zero @
193expression *E;
194@@
195
196(
197  E ==
198- 0
199+ NULL
200|
201  E !=
202- 0
203+ NULL
204|
205- 0
206+ NULL
207  == E
208|
209- 0
210+ NULL
211  != E
212)
213
214@ t3 depends on !patch disable is_zero,isnt_zero @
215expression *E;
216position p;
217@@
218
219(
220* E == 0@p
221|
222* E != 0@p
223|
224* 0@p == E
225|
226* 0@p != E
227)
228
229@script:python depends on org@
230p << t3.p;
231@@
232
233coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0")
234
235@script:python depends on report@
236p << t3.p;
237@@
238
239coccilib.report.print_report(p[0], "WARNING comparing pointer to 0")
240