Re: [PATCH 0/2] Improved flow graphs

[Josh Triplett <josh@freedesktop.org>]

[-- Attachment #1: Type: text/plain, Size: 1677 bytes --]

Dan Sheridan wrote:
> These two patches are the first of several implementing improved graph
> generation for Sparse.

Very nice work.  I've applied both patches in this series.

I also added shebangs to the gvpr scripts and made them executable, so you
can just run graph ... | gvpr/return-paths | dot ...

I noticed one minor issue: gvpr/return-paths seems to turn some internal
edges in functions into dotted-line return paths.

Also, unprocessed graphs have now become far more messy; for instance,
graphing validation/context.c generates numerous edges to a() and r().  Any
way you could prevent these edges from crossing other subgraphs?  Any way to
make these edges just point to a separate node "a()" and let people look up
a() themselves, removing the excess edges?  Perhaps with a gvpr script?

> Initially, I am dealing with straight-forward
> control flow. Forthcoming patches will add program dependency graphs (a
> control and data flow representation suitable for program slicing) and
> simple pointer alias analysis (for handling indirect calls).

I look forward to seeing these future enhancements.  Pointer alias analysis
would help greatly with many other things in Sparse.

> I've tried to keep the C part of the flow graph relatively simple, and
> put the hard stuff (like return edges and subgraph processing) in
> post-processing scripts. 
> 
> Example graph can be seen at
> http://www.postman.org.uk/djs52/example.png, generated with
> 
>   ./graph validation/context.c | gvpr -f gvpr/return-paths | \
>     gvpr -f gvpr/subg-fwd -a good_while3 | dot -Tpng > /tmp/example.png

Impressive work.

- Josh Triplett


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 252 bytes --]