> -----Original Message-----
> From: Peter Maydell <peter.mayd...@linaro.org>
> Sent: Tuesday, August 20, 2024 4:41 PM
> To: Yao, Xingtao/姚 幸涛 <yaoxt.f...@fujitsu.com>
> Cc: qemu-devel@nongnu.org
> Subject: Re: [PATCH] scripts/coccinelle: New range.cocci
>
> On Thu, 25 Jul 2024 at 06:55, Yao Xingtao via <qemu-devel@nongnu.org> wrote:
> >
> > This is the semantic patch from commit 7b3e371526 "cxl/mailbox: make
> > range overlap check more readable"
> >
> > Signed-off-by: Yao Xingtao <yaoxt.f...@fujitsu.com>
> > ---
> > scripts/coccinelle/range.cocci | 49
> ++++++++++++++++++++++++++++++++++
> > 1 file changed, 49 insertions(+)
> > create mode 100644 scripts/coccinelle/range.cocci
> >
> > diff --git a/scripts/coccinelle/range.cocci b/scripts/coccinelle/range.cocci
> > new file mode 100644
> > index 000000000000..21b07945ccb2
> > --- /dev/null
> > +++ b/scripts/coccinelle/range.cocci
> > @@ -0,0 +1,49 @@
> > +/*
> > + Usage:
> > +
> > + spatch \
> > + --macro-file scripts/cocci-macro-file.h \
> > + --sp-file scripts/coccinelle/range.cocci \
> > + --keep-comments \
> > + --in-place \
> > + --dir .
> > +
> > + Description:
> > + Find out the range overlap check and use ranges_overlap() instead.
> > +
> > + Note:
> > + This pattern cannot accurately match the region overlap check, and you
> > + need to manually delete the use cases that do not meet the conditions.
> > +
> > + In addition, the parameters of ranges_overlap() may be filled
> > incorrectly,
> > + and some use cases may be better to use range_overlaps_range().
>
> I think these restrictions mean that we should do one
> of two things:
> (1) rewrite this as a Coccinelle script that just prints
> out the places where it found matches (i.e. a "grep"
> type operation, not a search-and-replace), so the
> user can then go and investigate them and do the
> range_overlap they want to do
> (2) fix the problems so that you really can apply it to
> the source tree and get correct fixes
>
> The ideal would be (2) -- the ideal flow for coccinelle
> driven patches is that you can review the coccinelle
> script to check for things like off-by-one errors, and
> then can trust all the changes it makes. Otherwise
> reviewers need to carefully scrutinize each source
> change individually.
>
> It's the off-by-one issue that really makes me think
> that (2) would be preferable -- it would otherwise
> be I think quite easy to accidentally rewrite a correct
> range check into one that's off-by-one and not notice.
thanks for your reply!
I tried my best to match all the patterns of the region overlap check,
but it is difficult, I am not good at cocci, could you give me some advice?
>
> thanks
> -- PMM
