rjmccall added a comment. In https://reviews.llvm.org/D25556#572054, @ahatanak wrote:
> In https://reviews.llvm.org/D25556#569809, @rjmccall wrote: > > > Richard should probably weigh in about whether we should be recording > > potential captures at *all* capturing scopes. But at the very least, I > > think you have a bug here where the variable is declared outside of the > > block but within the lambda; in that case, it is definitely not a potential > > capture of the lambda. > > > Ah, that's a good point. > > When a variable is declared outside of the block but within the lambda, > CheckIfAnyEnclosingLambdasMustCaptureAnyPotentialCaptures in SemaExprCXX.cpp > will not capture the variable because > getStackIndexOfNearestEnclosingCaptureCapableLambda doesn't return a proper > index, so it looks like it's still safe to add the variable here even when it > cannot be captured by the lambda. I think it's possible to check that the > variable is not declared within the lambda before adding it to the list of > potential captures in the code above, but I'm not sure whether we have to do > that. > > Also, could you elaborate on when you think we don't have to record a > variable as a potential capture? My understanding is that you need to record > the variable as a potential capture when the variable is part of a full > expression that depends on a generic parameter because you don't know whether > the variable is odr-used and needs to be captured by the lambda until you > look at the full expression. Perhaps there are exceptions to this rule when > the variable is used in a block? I mean that it might be important for us to be recording this at block scopes, not just lambda scopes. Maybe not; I guess we do eagerly instantiate blocks, which we can't necessarily do with lambdas. This is something that Richard needs to weigh in on. https://reviews.llvm.org/D25556 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
