Re: Nullifying Recently Introduced Xen Headers Check

["John L. Poole" <johnlpoole@xxxxxxxxx>]

On Thursday, February 1st, 2024 at 9:18 AM, David Woodhouse 
<dwmw2@xxxxxxxxxxxxx> wrote:

> (Thanks Andy for the explicit cc)
> 
> On Thu, 2024-02-01 at 00:05 +0000, John L. Poole wrote:
> 
> > cause Gentoo's build to error out. See line 24790:
> > 
> > 5 | #error In Xen native files, include xen_native.h before other Xen 
> > headers
> > 
> > at
> > https://salemdata.us/xen/xen_tools_20240128_Sun_174740.script.html.
> > 
> > What I have done is create a patch for a draft Gentoo ebuild which
> > nullifies lines 4-6 by wrapping them in a comment:
> 
> 
> That isn't what the #error told you to do, though.
> 
> 24788 In file included from ../qemu-xen/hw/xen/xen-operations.c:16:
> 24789 
> /var/tmp/portage/app-emulation/xen-tools-4.18.0/work/xen-4.18.0/tools/qemu-xen/include/hw/xen/xen_native.h:5:2:
>  error: #error In Xen native files, include xen_native.h before other Xen 
> headers
> 24790 5 | #error In Xen native files, include xen_native.h before other Xen 
> headers
> 24791 | ^~~~~
> 
> So it's hw/xen/xen-operations.h which is failing. As far as I can tell
> (visually and empirically because it does actually build elsewhere), it
> is doing what the #error said — it is including xen_native.h before
> any other Xen headers.
> 
> The first four non-comment lines of xen-operations.c should look
> something like this...
> 
> #include "qemu/osdep.h"
> #include "qemu/uuid.h"
> #include "qapi/error.h"
> 
> #include "hw/xen/xen_native.h"
> 
> So... did you patch it so it doesn't start like that any more? Or does
> one of those first three files (perhaps qemu/osdep.h?) end up bringing
> in the Xen interface headers in a way that I didn't anticipate and
> which doesn't seem to happen elsewhere?
> 
> I didn't cite the full gcc command line from line 24787 of your log
> because it's huge. Can you run a variant of that command to just give
> me the preprocessed output (-E -dD -o xen-operations.i).

Hi David,

To answer your questions: the patch consists only of this
modification of 3 lines in xen_native.h:

   https://921932.bugs.gentoo.org/attachment.cgi?id=883883

Otherwise, the 4.18 code tree is as released.

I'm without the know-how to run a variant of the emerge command
as you have requested, alas.  I just simply removed 3 lines that
were introduced into the 4.18 tree to achieve a successful build.
I posted to this list to learn what the negative impacts might be. 

While the Xen Project "make" works, the Gentoo emerge
of app-emulation/xen-tools does not unless the three lines are
removed to simulate prior 4.17.3 and earlier code.  

I suspect the Gentoo approach 
of building tools first contributes to the problem.

Thank you,

John