Re: [RFC PATCH] configure: Poison (almost) all target-specific #defines

[Thomas Huth <thuth@redhat.com>]

On 15/03/2021 15.07, Claudio Fontana wrote:
> On 3/15/21 2:54 PM, Thomas Huth wrote:
>> We are generating a lot of target-specific defines in the *-config-devices.h
>> and *-config-target.h files. Using them in common code is wrong and leads
>> to very subtle bugs since a "#ifdef CONFIG_SOMETHING" is not working there
>> as expected. To avoid these issues, we are already poisoning some of the
>> macros in include/exec/poison.h - but maintaining this list manually is
>> cumbersome. Thus let's generate the list of poisoned macros automatically
>> instead.
>> Note that CONFIG_TCG (which is also defined in config-host.h) and
>> CONFIG_USER_ONLY are special, so we have to filter these out.
> 
> 
> 
> I have the impression that CONFIG_USER_ONLY should be poisoned too.
> 
> A lot of the
> 
> #ifndef CONFIG_USER_ONLY
> 
> end up currently doing the wrong thing in common modules includes,
> especially due to the inverted nature of the check.

Not sure about that ... do you have an example at hand?

Anyway, one thing is sure, if we want to poison CONFIG_USER_ONLY, this will 
certainly cause a lot of clean up work first, since it is used all over the 
place...

  Thomas