[PATCH] D12301: [PATCH] New checker for UB in handler of a function-try-block

[Aaron Ballman via cfe-commits]

On Mon, Aug 24, 2015 at 6:29 PM, Richard Smith <richard at metafoo.co.uk> wrote:
> On Mon, Aug 24, 2015 at 3:23 PM, Aaron Ballman <aaron.ballman at gmail.com>
> wrote:
>>
>> aaron.ballman created this revision.
>> aaron.ballman added reviewers: alexfh, rsmith.
>> aaron.ballman added a subscriber: cfe-commits.
>>
>> Per [except.handle]p10, the handler for a constructor or destructor
>> function-try-block cannot refer to a non-static member of the object under
>> construction. This patch adds a new clang-tidy check that warns the user
>> when they've hit this undefined behavior.
>>
>> Due to how infrequent function-try-blocks appear on constructors and
>> destructors in the wild compared to how often member expressions are
>> encountered, I felt this was more appropriate as a clang-tidy check than as
>> a semantic warning. I was concerned with efficiency of checking whether an
>> arbitrary member expression was referring to the object under
>> construction/destruction within the function-try-block catch handler scope.
>
>
> Seems like this would be very cheap to check in the case where the object
> expression is an implicit or explicit CXXThisExpr. It'd be good to have a
> frontend warning for that case.

Are you thinking the check would likely in BuildMemberReferenceExpr()
and I would just have to look at the current scope to determine
whether it's a function-try-block catch handler? When I looked into
doing a frontend warning for this, I seemed to struggle with figuring
out specifically that I was in the catch handler of a
function-try-block of a constructor or destructor.

~Aaron

>
>>
>> This patch corresponds to the CERT secure coding rule ERR53-CPP
>> (https://www.securecoding.cert.org/confluence/display/cplusplus/ERR53-CPP.+Do+not+reference+base+classes+or+class+data+members+in+a+constructor+or+destructor+function-try-block+handler)
>>
>> http://reviews.llvm.org/D12301
>>
>> Files:
>>   clang-tidy/misc/CDtorCatchHandlerCheck.cpp
>>   clang-tidy/misc/CDtorCatchHandlerCheck.h
>>   clang-tidy/misc/CMakeLists.txt
>>   clang-tidy/misc/MiscTidyModule.cpp
>>   test/clang-tidy/misc-cdtor-catch-handler.cpp
>>
>