PING [PATCH v2 2/2] add -Wdangling-pointer [PR #63272]

[Martin Sebor <msebor@gmail.com>]

Ping:
https://gcc.gnu.org/pipermail/gcc-patches/2021-November/585819.html

On 11/30/21 3:55 PM, Martin Sebor wrote:
> Attached is a revision of this patch with adjustments for
> the changes to the prerequisite patch 1 in the series and
> a couple of minor simplifications and slightly improved
> test coverage, rested on x86_64-linux.
> 
> On 11/1/21 4:18 PM, Martin Sebor wrote:
>> Patch 2 in this series adds support for detecting the uses of
>> dangling pointers: those to auto objects that have gone out of
>> scope.  Like patch 1, to minimize false positives this detection
>> is very simplistic.  However, thanks to the more deterministic
>> nature of the problem (all local objects go out of scope) is able
>> to detect more instances of it.  The approach I used is to simply
>> search the IL for clobbers that dominate uses of pointers to
>> the clobbered objects.  If such a use is found that's not
>> followed by a clobber of the same object the warning triggers.
>> Similar to -Wuse-after-free, the new -Wdangling-pointer option
>> has multiple levels: level 1 to detect unconditional uses and
>> level 2 to flag conditional ones.  Unlike with -Wuse-after-free
>> there is no use case for testing dangling pointers for
>> equality, so there is no level 3.
>>
>> Tested on x86_64-linux and  by building Glibc and Binutils/GDB.
>> It found no problems outside of the GCC test suite.
>>
>> As with the first patch in this series, the tests contain a number
>> of xfails due to known limitations marked with pr??????.  I'll
>> open bugs for them before committing the patch if I don't resolve
>> them first in a followup.
>>
>> Martin
>