[Lldb-commits] [PATCH] D113174: [lldb] Summary provider for char flexible array members

Fri Nov 5 12:05:15 PDT 2021

shafik added a comment.

In D113174#3109664 <https://reviews.llvm.org/D113174#3109664>, @jingham wrote:

> Regex Type summary matching happens after the ConstString matching.  Enrico did it that way because the ConstString matching is so much quicker, so if we can find a match there we'll get to it more quickly...
>
> So this patch moves the char * recognition from the beginning of the type summary matching to the end, and potentially makes it a slower match.
>
> I doubt that this will be noticeable on modern systems, however, just something to keep in mind.
>
> It also changes the order of search slightly.  I think this is observable: it would mean a regex that happens to match "char *" as well as other things used to not be chosen for "char *" because it would have hit the ConstString summary first.  Now it will match, because the built-in regex summary will be checked after the user added ones.
>
> Again, I don't think this is a reason not to do the patch.  But something to keep in mind.  The code itself looks fine.

I was looking at these char formatters a while ago and IIRC I did see some impact making these regex matches but I don't remember the details and did not look closely (so maybe there was another effect at play) b/c I went with a different approach.

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https://reviews.llvm.org/D113174