Re: [Qemu-devel] [PATCH 4/7] provide opaque CPUState to files that are compiled once

[Paolo Bonzini <pbonzini@redhat.com>]

On 06/27/2010 09:17 PM, Blue Swirl wrote:
> I'm not comfortable with this part. Accidental use of the global
> register variable can cause subtle bugs. I'd rather rename 'env' to
> something more obvious and less likely to collide, like
> 'global_reg_env' and always poison that. Then we could replace 'env1'
> etc with just 'env'.

This is not very different from before thanks to the reordering of 
includes done in this patch.

All target-*/exec.h files now start with

#include "config.h"
#include "dyngen-exec.h"
#include "cpu.h"
#include "exec-all.h"

// sometimes a few #defines

register struct CPUAlphaState *env asm(AREG0);

And so they cannot use the global env unless NEED_CPU_H is defined.  If 
anything, it's clearer than before because the structure of the initial 
#includes is the same for all targets.

It's true that a "NEED_GLOBAL_ENV" would provide even better safety, but 
that's something for a separate patch series.  It's particularly easy to 
do after replacing CPU<Target>State with CPUState, so that it can be 
moved into exec-all.h, but this series is already big enough IMO.  Let's 
do cleanups one thing at a time please.

Paolo