Re: [Qemu-devel] [6967] Temporary workaround for ppc on ppc

[malc <av1474@comtv.ru>]

On Thu, 2 Apr 2009, Blue Swirl wrote:

> On 4/2/09, malc <av1474@comtv.ru> wrote:
> > Revision: 6967
> >           http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6967
> >  Author:   malc
> >  Date:     2009-04-02 01:16:39 +0000 (Thu, 02 Apr 2009)
> >  Log Message:
> >  -----------
> >  Temporary workaround for ppc on ppc
> >
> >  target-ppc/translate.c puts values of type opcode_t into .opcodes
> >  section, using GCC extension to do so, and hoping that this will make
> >  them appear contiguously and in the source order in the resulting
> >  executable. This assumption is not safe and is known to be violated
> >  with certain versions of GCC, certain flags passed to it and on
> >  certain platforms (gcc 4.3.0, -O and PPC/PPC64 for instance)
> 
> I've always wondered if the section hack was a very clever one or too
> clever one, this makes it clear.
> 
> The section uses could be removed by moving the opcode tables towards

There are _no_ opcode tables that's why it fails. The code just does

opcode_t in_section(.opcodes) start;
<lots of opcode_t>;
opcode_t in_section(.opcodes) end;

And then scans from &start to &end.

The only way, that i know of, to make that work is to indeed put
things into a table (an array).

> the end of file and making the handler functions use normal C
> declarations or aided with a macro. That separates the function and
> its table entry a lot, but I guess we don't want to use the #include
> trick this time?

I think PPC's translate.c should be just split and massaged a lot.

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