[Cocci] [PATCH] Coccinelle: doubletest: reduce side effect false positives

Julia Lawall Julia.Lawall at lip6.fr
Fri Aug 3 18:32:11 CEST 2018


Ensure that the cited expression is not a function call or an
assignment to reduce the chance of false positives.

Slightly modify the warning message to indicate another source
of false positves.

Signed-off-by: Julia Lawall <Julia.Lawall at lip6.fr>

---
 scripts/coccinelle/tests/doubletest.cocci |   34 ++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/scripts/coccinelle/tests/doubletest.cocci b/scripts/coccinelle/tests/doubletest.cocci
index 78d74c2..7af2ce7 100644
--- a/scripts/coccinelle/tests/doubletest.cocci
+++ b/scripts/coccinelle/tests/doubletest.cocci
@@ -1,6 +1,7 @@
 /// Find &&/|| operations that include the same argument more than once
-//# A common source of false positives is when the argument performs a side
-//# effect.
+//# A common source of false positives is when the expression, or
+//# another expresssion in the same && or || operation, performs a
+//# side effect.
 ///
 // Confidence: Moderate
 // Copyright: (C) 2010 Nicolas Palix, DIKU.  GPLv2.
@@ -20,20 +21,37 @@ position p;
 @@
 
 (
-* E at p
-  || ... || E
+ E at p || ... || E
 |
-* E at p
-  && ... && E
+ E at p && ... && E
 )
 
- at script:python depends on org@
+ at bad@
+expression r.E,e1,e2,fn;
+position r.p;
+assignment operator op;
+@@
+
+(
+E at p
+&
+ <+... \(fn(...)\|e1 op e2\|e1++\|e1--\|++e1\|--e1\) ...+>
+)
+
+ at depends on context && !bad@
+expression r.E;
+position r.p;
+@@
+
+*E at p
+
+ at script:python depends on org && !bad@
 p << r.p;
 @@
 
 cocci.print_main("duplicated argument to && or ||",p)
 
- at script:python depends on report@
+ at script:python depends on report && !bad@
 p << r.p;
 @@
 



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