Re: [XEN PATCH v7 20/51] build: avoid re-executing the main Makefile by introducing build.mk

[Jan Beulich <jbeulich@xxxxxxxx>]

On 11.10.2021 19:07, Anthony PERARD wrote:
> On Mon, Oct 11, 2021 at 05:31:08PM +0200, Jan Beulich wrote:
>> On 11.10.2021 16:58, Anthony PERARD wrote:
>>> On Mon, Oct 11, 2021 at 12:56:54PM +0200, Jan Beulich wrote:
>>>> On 24.08.2021 12:50, Anthony PERARD wrote:
>>>>> With nearly everything needed to move to "build.mk" moved, there is a
>>>>> single dependency left from "Rules.mk": $(TARGET), which is moved to
>>>>> the main Makefile.
>>>>
>>>> I'm having trouble identifying what this describes. Searching for
>>>> $(TARGET) in the patch doesn't yield any obvious match. Thinking
>>>> about it, do you perhaps mean the setting of that variable? Is
>>>> moving that guaranteed to not leave the variable undefined? Or in
>>>> other words is there no scenario at all where xen/Makefile might
>>>> get bypassed? (Aiui building an individual .o, .i, or .s would
>>>> continue to be fine, but it feels like something along these lines
>>>> might get broken.)
>>>
>>> I mean that "xen/Rules.mk" will never "include" "xen/Makefile" after
>>> this patch, but the variable "TARGET" is only set in "xen/Rules.mk". But
>>> "xen/Makefile" still needs "TARGET" to be set so I moved the assignment
>>> of the variable from "xen/Rules.mk" into "xen/Makefile".
>>
>> Okay, thanks, this confirms the understanding I had developed; maybe
>> you try to reword this some. What your reply doesn't address is my
>> question, though.
> 
> Which question, there seems to be 3 of them :-). Is it about
> xen/Makefile been bypassed?

Yes, sorry for being imprecise.

> Building anything in xen/ requires to first execute xen/Makefile as this
> is where variables like CFLAGS or XEN_ROOT are defined, and this
> includes single builds or building an individual .o.

Okay, thanks for confirming.

Jan