Fwd: Fixed function compilation order

[Cupertino Miranda <cupertinomiranda at gmail dot com>]

Yesterday by mistake I started some private discussion with Daniel.
I will forward his answer too.

Begin forwarded message:

> From: Cupertino Miranda <cupertinomiranda@gmail.com>
> Date: August 9, 2007 2:24:04 AM CEDT
> To: Daniel Berlin <dberlin@dberlin.org>
> Subject: Re: Fixed function compilation order
>
>
> On Aug 9, 2007, at 2:03 AM, Daniel Berlin wrote:
>
> > On 8/8/07, Cupertino Miranda <cupertinomiranda@gmail.com> wrote:
> > > Hello everyone,
> > >
> > > I am currently trying to enable GCC to perform compilation without
> > > having to respect any compilation order, i.e. execute some pass to
> > > any function at any time (it is not only pass reordering).
> >
> > > As what I have seen from (trunk version of) GCC, it doesn't seem an
> > > easy task to be achieved and it might traduce in many complications
> > > later in development.
> > > In that sense I would like to have some opinions and suggestions  
> > > from
> > > you all:
> >
> >
> > For tree level optimization, this is really not difficult.
> > For RTL, this is probably going to be really hard.
> > >   - Imagining I am able to change the function context by updating
> > > cfun, etc. Will passes (all_passes) execute without
> > > missing/wrong data, i.e. is all shared data between passes accessed/
> > > updated thought pointers such as cfun, etc. ?
> >
> > What do you mean "missing/wrong" data.
>
> Just as an example, imagine you just executed the pass for the  
> creation of the CFG and after that, you decided to change context  
> to another function to perform the same pass. Will I have to keep  
> track of this CFG or it is also available and used (by other  
> passes) through the "high level" structures pointed by cfun, etc. ?
> The CFG is just an example to possible very small "detail" data- 
> structures that might exist in GCC and not such an obvious thing as  
> a CFG. ;-)
> > >   - What should I initialise/finalise to be able to perform the
> > > function context change ?
> >
> > See any IPA pass
> > > I would like to have your opinion and tips on how to approach it and
> > > which problems I might expect to have later.
> > >
> > > Thanks in advance,
> > > Cupertino Miranda