1/// Compare pointer-typed values to NULL rather than 0
  2///
  3//# This makes an effort to choose between !x and x == NULL.  !x is used
  4//# if it has previously been used with the function used to initialize x.
  5//# This relies on type information.  More type information can be obtained
  6//# using the option -all_includes and the option -I to specify an
  7//# include path.
  8//
  9// Confidence: High
 10// Copyright: (C) 2012 Julia Lawall, INRIA/LIP6.  GPLv2.
 11// Copyright: (C) 2012 Gilles Muller, INRIA/LiP6.  GPLv2.
 12// URL: http://coccinelle.lip6.fr/
 13// Requires: 1.0.0
 14// Options:
 15
 16virtual patch
 17virtual context
 18virtual org
 19virtual report
 20
 21@initialize:ocaml@
 22@@
 23let negtable = Hashtbl.create 101
 24
 25@depends on patch@
 26expression *E;
 27identifier f;
 28@@
 29
 30(
 31  (E = f(...)) ==
 32- 0
 33+ NULL
 34|
 35  (E = f(...)) !=
 36- 0
 37+ NULL
 38|
 39- 0
 40+ NULL
 41  == (E = f(...))
 42|
 43- 0
 44+ NULL
 45  != (E = f(...))
 46)
 47
 48
 49@t1 depends on !patch@
 50expression *E;
 51identifier f;
 52position p;
 53@@
 54
 55(
 56  (E = f(...)) ==
 57* 0@p
 58|
 59  (E = f(...)) !=
 60* 0@p
 61|
 62* 0@p
 63  == (E = f(...))
 64|
 65* 0@p
 66  != (E = f(...))
 67)
 68
 69@script:python depends on org@
 70p << t1.p;
 71@@
 72
 73coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0")
 74
 75@script:python depends on report@
 76p << t1.p;
 77@@
 78
 79coccilib.report.print_report(p[0], "WARNING comparing pointer to 0")
 80
 81// Tests of returned values
 82
 83@s@
 84identifier f;
 85expression E,E1;
 86@@
 87
 88 E = f(...)
 89 ... when != E = E1
 90 !E
 91
 92@script:ocaml depends on s@
 93f << s.f;
 94@@
 95
 96try let _ = Hashtbl.find negtable f in ()
 97with Not_found -> Hashtbl.add negtable f ()
 98
 99@ r disable is_zero,isnt_zero exists @
100expression *E;
101identifier f;
102@@
103
104E = f(...)
105...
106(E == 0
107|E != 0
108|0 == E
109|0 != E
110)
111
112@script:ocaml@
113f << r.f;
114@@
115
116try let _ = Hashtbl.find negtable f in ()
117with Not_found -> include_match false
118
119// This rule may lead to inconsistent path problems, if E is defined in two
120// places
121@ depends on patch disable is_zero,isnt_zero @
122expression *E;
123expression E1;
124identifier r.f;
125@@
126
127E = f(...)
128<...
129(
130- E == 0
131+ !E
132|
133- E != 0
134+ E
135|
136- 0 == E
137+ !E
138|
139- 0 != E
140+ E
141)
142...>
143?E = E1
144
145@t2 depends on !patch disable is_zero,isnt_zero @
146expression *E;
147expression E1;
148identifier r.f;
149position p1;
150position p2;
151@@
152
153E = f(...)
154<...
155(
156* E == 0@p1
157|
158* E != 0@p2
159|
160* 0@p1 == E
161|
162* 0@p1 != E
163)
164...>
165?E = E1
166
167@script:python depends on org@
168p << t2.p1;
169@@
170
171coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0, suggest !E")
172
173@script:python depends on org@
174p << t2.p2;
175@@
176
177coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0")
178
179@script:python depends on report@
180p << t2.p1;
181@@
182
183coccilib.report.print_report(p[0], "WARNING comparing pointer to 0, suggest !E")
184
185@script:python depends on report@
186p << t2.p2;
187@@
188
189coccilib.report.print_report(p[0], "WARNING comparing pointer to 0")
190
191@ depends on patch disable is_zero,isnt_zero @
192expression *E;
193@@
194
195(
196  E ==
197- 0
198+ NULL
199|
200  E !=
201- 0
202+ NULL
203|
204- 0
205+ NULL
206  == E
207|
208- 0
209+ NULL
210  != E
211)
212
213@ t3 depends on !patch disable is_zero,isnt_zero @
214expression *E;
215position p;
216@@
217
218(
219* E == 0@p
220|
221* E != 0@p
222|
223* 0@p == E
224|
225* 0@p != E
226)
227
228@script:python depends on org@
229p << t3.p;
230@@
231
232coccilib.org.print_todo(p[0], "WARNING comparing pointer to 0")
233
234@script:python depends on report@
235p << t3.p;
236@@
237
238coccilib.report.print_report(p[0], "WARNING comparing pointer to 0")