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Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem
From: |
Rob Landley |
Subject: |
Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it? |
Date: |
Fri, 11 May 2007 19:39:40 -0400 |
User-agent: |
KMail/1.9.1 |
On Thursday 10 May 2007 8:01 pm, David A. Wheeler wrote:
> Philippe Ribet:
> > The initial goal of tcc is to be very fast and very small. Adding
> > optimiser capabilities will make the code bigger, harder to understand
> > and maintain, tcc runing slower... I think it will be another project.
>
> It's a waste of time to work really hard at optimization in tcc,
Certainly not by default. If we make it cleanly layered enough that people
can plug something in, in a separate file, fine. Dunno if that's possible
and it's not something to worry about until it builds a working Linux kernel.
> but I think
> that one _IS_ within the spirit of tcc, for two reasons:
> * tcc _does_ include a number of optimizations, as long as they're "easy".
> For example, it does constant folding. I think this is another easy one.
Dead code elimination and constant propogation are two others that compilers
running under DOS in the 1980's managed to do. Can't be _that_ hard...
> * Fabrice Bellard made sure that tcc could boot the Linux kernel.
Technically he made it boot a modified subset the Linux kernel, but yeah.
> Unfortunately, that probably will fail, because the Linux kernel developers
> are moving to smaller (4K) stacks exclusively. Adding an optimization that
> changes not-working to working, esp. a for program that tcc's developer
> SPECIFICALLY supported, makes sense.
Perhaps we can have a "-O" flag.
> Usually optimizations just make programs a little faster. This optimization
> may become necessary to run an important program, period.
Dead code elimination is another one: BusyBox requires it. (The config system
uses it to remove code that's configured out. Without it, calls get made to
*.c files we don't compile and link in for a given configuration.)
Rob
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, (continued)
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, Daniel Glöckner, 2007/05/08
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, David A. Wheeler, 2007/05/08
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, Daniel Glöckner, 2007/05/08
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, David A. Wheeler, 2007/05/08
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, Philippe Ribet, 2007/05/10
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, David A. Wheeler, 2007/05/10
- Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?,
Rob Landley <=
Re: [Tinycc-devel] Proposal for handling alloca(). Anyone see a problem with it?, Dave Dodge, 2007/05/08