[cfe-commits] PATCH: Fix false negatives when warning about using uninitialized variables

[Ted Kremenek]

This looks great to me.  I'll go ahead and commit.

On Jul 14, 2011, at 4:33 PM, Kaelyn Uhrain wrote:

> As reported in PR 10358, code such as:
> 
> void foo(int y) {
>   int x; // Undefined.
>   do {
>     y+=x;
>   } while (1);
> }
> 
> will only trigger a warning about x being uninitialized when -Wconditional-uninitialized because the uninitialized variables are mistakenly marked as possibly being assigned to before use. The attached patch makes a few tiny changes to lib/Analysis/UninitializedValues.cpp to not  mark uninitialized variables as Initialized just to avoid cascaded warnings. Instead it marks them as Unknown (part of the local Value enum) so that isUninitialized() will still return false but variables don't accidentally get marked as maybe unitialized by calls to CFGBlockValues::mergeIntoScratch when they are definitely uninitialized (through it being marked as Uninitialized in one packed vector and Initialized in the other, and the two values being or'ed together to become MayUninitialized).
> 
> The patch also fixes up the four cases in test/Sema/uninit-variables.c where a "may be uninitialized" should rightfully be "is uninitialized".
> 
> Cheers,
> Kaelyn
> <uninit-var-warning-fix.diff>_______________________________________________
> cfe-commits mailing list
> cfe-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits