[cfe-dev] static analysis inlining varargs functions

[Anna Zaks]

> On Mar 17, 2015, at 1:21 PM, Bob Kuo <Bob.Kuo at riverbed.com> wrote:
> 
> Hello clang developers,
> 
> We recently found a memory leak at work we were not freeing allocated memory returned by the standard C string strdup() function.  I ran the static analyzer against a version of the code with the defect and it didn't detect a memory leak.  When I reduced the code to a simpler test case the static analyzer correctly identified the leak.  After a few iterations I found that the culprit was a varargs function where the variable that held a reference to the allocated memory was a parameter.  With the call to the varargs function commented out, the static analyzer identified the leak.  With the call to the varargs function no warning was produced. 
> 
> Is this a design decision or inherent limit in the static analyzer?  Is this a known issue?  I didn't see any bugs in the tracker.  Should I file a bug?
> 

I am not sure if it is related to the function being varargs or just passing the reference to a function the analyzer does not see. Can you check that?

When a pointer to allocated memory is passed to a function that the analyzer does not see, the analyzer assumes that that function could free it. (This is by design to reduce the number of false positives.)

> Thanks,
> 
> Bob Kuo
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