inlining methods in slang

Martin Kuball MartinKuball at
Thu May 5 19:37:27 UTC 2005

Am Tuesday 03 May 2005 21:46 schrieb Tim Rowledge:
> Martin Kuball <MartinKuball at> wrote:
> > Am Monday 02 May 2005 09:48 schrieb John M McIntosh:
> > > You should look at
> > > CCodeGenerator>>collectInlineList
> > >
> > > to understand why your code does not get inlined.
> >
> > Well, the offending line is
> >    self var: #output type: 'unsigned char*'.
> >
> > The inlined code can do well without it. But the code generated
> > for the method does not compile without it. So my question is
> > still: why do inlined methods get their own c method definitions?
> > I think I could live without them.
> It's all down to how clever (or stupid) the inlining code is. Since
> the inlining is done purely on a textual basis it isn't smart
> enough to do semantic analysis or C block analysis etc; so when you
> have any C declaration in a translated method it gets marked as
> non-inlinable. Note the line in #collectInlineList that goes
>  hasCCode := m declarations size > 0.
> and consider it along with TMethod>recordDeclarations. If you (or
> anyone) can think of a way to handle C declarations in the inlining
> process, don't hesitate to suggest code.
Well, I think you can safely ignore the var:type: message. If the 
"input" variable in the method that contains the inlined code does 
not have the right type, you are in trouble anyway.
And I don't see a problem with declarations for local variables 
either. The declarations are added to the other declarations of the 
method thas includes the inlined code. You just use the givent type 
instead of int. Where is the problem?

> An alternative that hasn't been tried yet is to stop doing the
> inlining ourselves and instead mark generated functions for the C
> compiler to inline. So far as I can tell all current C compilers
> accept an inline pragma and I suspect could do a much better job.
> Someone with some time and a wish to help might like to
> investigate. Generate the VM code with our inlining turned off but
> add some code to stick the C inline pragma in the function
> declarations when we have a self inline: true.  Run sensible
> benchmark suites. Gain fame.
Sounds good.


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