Re: [Cardinal-dev] Compiler structure / AST format

[Dan Sugalski]

At 4:05 AM +0300 4/25/02, Einar Karttunen wrote:
> On 24.04 17:39, Phil Tomson wrote:
>  > The intermediate would make it eaiser to 'bolt-on' other VMs or to compile
> >  the intermediate to native code (like what is done in .NET and it's clr).
>
> The reason for the immediate is the optimiser pass and the 
> complexity of backends.
> * backends need to only know about the intermediate code not the AST
> * frontends and backends can be switched with no recoding
> * some optimisations common to all backends are very unnatural at 
> the AST level

I'll point out that some optimisations common to all backends are 
very natural to do at the AST level. Most compilers I know of have at 
least three different intermediate representations of the code for 
the optimiser because of the different characteristics of the 
different optimisations. Some work best with a high-level 
representation, some with a medium-level representation, and some 
with a low-level representation.
--
                                        Dan

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Dan Sugalski                          even samurai
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