On Mon, Aug 24, 2015 at 3:36 PM, Aaron Ballman <aaron.ball...@gmail.com> wrote:
> On Mon, Aug 24, 2015 at 6:29 PM, Richard Smith <rich...@metafoo.co.uk> > wrote: > > On Mon, Aug 24, 2015 at 3:23 PM, Aaron Ballman <aaron.ball...@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? Yes, somewhere around there. You might need to wire a Scope* though a couple of layers though. > 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. Looks like there's no better method than walking up the Scope stack until you hit a scope with the FnTryCatchScope flag (or leave the function), currently.
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