[cfe-commits] r128894 - in /cfe/trunk: lib/Sema/AnalysisBasedWarnings.cpp test/Sema/uninit-variables.c test/SemaCXX/uninitialized.cpp

[Chandler Carruth]

On Tue, Apr 5, 2011 at 11:11 AM, Ted Kremenek <kremenek at apple.com> wrote:

> The problem is that the analysis currently treats 'x' to be initialized,
> regardless of whatever is in the initializer.  This is done to halt the
> propagation of uninitialized values warnings, and only report the earliest
> instance.  The real fix probably needs to be done in the analysis
> (UninitializedValues.cpp), not in the error reporting side in
> AnalysisBasedWarnings.cpp.


Interesting! I didn't realize this subtlety, thanks for pointing it out.
Sorry for not adding a test case that would exercise it and seeing it, I
misread one of the existing tests as covering this... my bad on that front.

I'm looking at this and I wonder what the best way to do this is. Clearly we
need to not flag 'x' as initialized in UninitializedValues.cpp.

Do we want to avoid marking the initializer's reference an uninitialized use
inside of UninitializedValues.cpp and remove that logic from
AnalysisBasedWarnings?

Or do we want to just prevent the variable from being marked as initialized
in this particular case, and handle any and all suppression or other logic
inside AnalysisBasedWarnings?

I lean toward the latter as it keeps the model in the analyzer more pure.
Even this much special casing in UninitializedValues.cpp seems really
unfortunate. How important is continuing to warn on later uses of 'x'? I
think its probably worthwhile to have the analyzer propagate through this
one layer, but it seems a bit close.
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