Re: [Qemu-devel] [PATCH] Fix dyngen failure on PPC.

[Paul Brook <paul@codesourcery.com>]

On Sunday 01 May 2005 21:15, Flavio Visentin wrote:
> > This is not correct.
> > If the blr is not at the end of the function, things will break.
>
> [SNIP]
>
> > This basically only ever worked because gcc could be coerced into
> > generating relatively simple code. GCC4 contains much more aggressive
> > high level optimizers, so this is no longer possible.
>
> I don't know almost anything about gcc, so I'm asking two questions:
>
> 1) Isn't there any kind of compiler directive to force no optimization
> only for a portion of the code?

Optimiziation is controlled on a per-file bases.

> 2) If there aren't such directives is it possible to link together
> optimized obj with not optimized obj? In this case you could group
> functions that require no optimization and link them with the other
> optimized code.

Linking together objects compiled with and without optimization isn't a 
problem, however...

Disabling optimization isn't really an option because (a) it causes other 
problems, and (b) the code generate is awfully slow.
The real solution is to teach qemu how to generate native code from and remove 
dyngen altogether, but that's a lot of work. Look in the list archives for 
more details.

Paul