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: https://coccinelle.gitlabpages.inria.fr/website
 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")