[PATCH]: Implementation of -Wcast-qual

[Roman Divacky]

Like this?

On Fri, Nov 14, 2014 at 11:20:49AM -0800, David Blaikie wrote:
> I take it this is consistent with the GCC warning - in terms of warning on
> the innermost issue, reporting const or volatile - what about dropping
> const and volatile at the same time?
> 
> Issues with the current code:
> 
> * DestPtr and SrcPtr don't need to be initialized to null, they'll be
> written to on the first loop iteration as needed - avoiding excess
> initialization helps tools like MSan find more bugs rather than the program
> silently using unintended default values
> 
> * InnerMostDestType and InnerMostSrcType will be dangling pointers after
> the while loop (so accessing them in the proceeding 'if' is UB)
> 
> * you don't need to check both InnerMostDestType and InnerMostSrcType in
> the following if - it's invariant that if one is non-null (you can use
> QualType values rather than QualType* to address the previous bug, and use
> QualTypes "isNull()" member function here) so is the other
> 
> On Fri, Nov 14, 2014 at 11:07 AM, Roman Divacky <rdivacky at vlakno.cz> wrote:
> 
> > Actually, try this patch. It includes check for volatile as well.
> >
> > On Wed, Nov 12, 2014 at 12:39:20PM -0800, David Blaikie wrote:
> > > [+Richard for oversight]
> > >
> > > char **y1 = (char **)ptrptr; // expected-warning {{cast from 'const char
> > > *const *' to 'char **' drops const qualifier}} expected-warning {{cast
> > from
> > > 'const char *const' to 'char *' drops const qualifier}}
> > >
> > > I think if we're going to warn on multiple layers (I'm not sure that's
> > > ideal - is that consistent with GCC's warning? Does GCC warn on
> > mismatched
> > > types too - "const T*" -> "U*"? - do we warn there too, or only when
> > > there's a valid implicit conversion like the void* example?) then we
> > should
> > > probably drop the top level const, "const char *const" -> "char*" - the
> > top
> > > level const on the first type is confusing/misleading, it's only relevant
> > > to show "const char*" and "char*".
> > >
> > >
> > > On Wed, Nov 12, 2014 at 10:41 AM, Roman Divacky <rdivacky at vlakno.cz>
> > wrote:
> > >
> > > > I expanded the testcase and fixed the grammar in the actual warning.
> > > >
> > > > New patch attached.
> > > >
> > > > On Tue, Nov 11, 2014 at 05:03:33PM -0800, David Blaikie wrote:
> > > > > (it's a bit easier if you include the test in the same patch file -
> > also
> > > > > you can use Phabricator if you like - some reviewers perefer it)
> > > > >
> > > > > Since you've got the loop there for seeing through multiple levels of
> > > > > pointer, should you have a test case that exercises that on a > 1
> > level
> > > > of
> > > > > depth? Demonstrate that we warn on both levels (if that's the right
> > thing
> > > > > to do?)?
> > > > >
> > > > > Optionally (probably in a separate follow-up patch) you could add a
> > note
> > > > > with a fixit to include the missing consts.
> > > > >
> > > > > On Tue, Nov 11, 2014 at 10:58 AM, Roman Divacky <rdivacky at vlakno.cz>
> > > > wrote:
> > > > >
> > > > > > Hi,
> > > > > >
> > > > > > I implemented -Wcast-qual. The patch is actually quite short
> > (attached
> > > > + a
> > > > > > test
> > > > > > case).
> > > > > >
> > > > > > This fixes #13772 and also note that -Wcast-qual is used in llvm
> > build
> > > > > > itself.
> > > > > >
> > > > > > Is this ok to be commited? Thanks
> > > > > >
> > > > > > Roman
> > > > > >
> > > > > >
> > > > > > _______________________________________________
> > > > > > cfe-commits mailing list
> > > > > > cfe-commits at cs.uiuc.edu
> > > > > > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
> > > > > >
> > > > > >
> > > >
> >
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