[cfe-dev] Dead stores of NULLs
nikita at zhuk.fi
Thu Jun 19 17:40:37 PDT 2008
First I would like to express my appreciation for the great static
analyzer, which is already producing useful results. I've been able to
find several memory leaks and some dead stores. However, I would like
to address an issue which produces some dead store reports which are
technically correct (they really are dead stores), but I would still
like to ignore them.
When I allocate an object (by using alloc & init* or one of the
*Create* functions) and store it into a local variable inside some
scope, I tend to set it to nil/NULL after the object has been
released. This is an intentional dead store, which prevents any use of
that released object later in the same scope. For example:
- (void)doSomethingWithFileExtension:(NSString *)ext
CFStringRef fileUti =
// use 'fileUti'...
fileUti = NULL; // Dead store, reported correctly by 'scan-build'
// From now on, any unintentional use of 'fileUti' variable in this
method will cause predictable runtime behaviour.
// If it'll be passed to some other methods, precondition assertions
of those methods will catch it early etc.
Would it be useful to add a flag to ignore nil/NULL dead stores?
More information about the cfe-dev