[OE-core] a few more picky questions about COMPATIBLE_MACHINE usage

[Robert P. J. Day]

On Mon, 27 Feb 2017, Phil Blundell wrote:

> On Mon, 2017-02-27 at 09:09 -0500, Robert P. J. Day wrote:
> >  # webkit-efl isn't available for < armv7a
> >  COMPATIBLE_MACHINE = "(-)"
> >   COMPATIBLE_MACHINE_x86 = "(.*)"
> >   COMPATIBLE_MACHINE_x86-64 = "(.*)"
> >   COMPATIBLE_MACHINE_armv7a = "(.*)"
> >
> >   first, that comment seems out of date as it makes no mention of
> > MIPS
> > or ppc, but that's just being picky.
> >
> >   next, i assume the line:
> >
> >   COMPATIBLE_MACHINE = "(-)"
> >
> > is to initialize the set of compatible machines to the empty set,
> > yes?
>
> I think the intent is to set it to a string that "can't possibly
> ever match".

  right, that's what i suspected.

> >
>   i next assume that lines of the form:
> >
> >   COMPATIBLE_MACHINE_x86 = "(.*)"
> >
> > are meant to indicate that if that MACHINE_OVERRIDES comparison
> > succeeds, then all possible targets are compatible, is that right?
> > however, given precisely those lines above, is it not equivalent to
> > just write:
> >
> >   COMPATIBLE_MACHINE = "(x86|x86-64|armv7a)"
>
> No, because "armv7a" is not a MACHINE.  It would be more equivalent
> to write
>
> COMPATIBLE_HOST = "armv7a-.*"
>
> but even this would not be quite the same because it would fail to
> match "cortexa15-linux" for example.  Actually that's not a very
> good example because cortexa15 is armv7ve not armv7a, but you get
> the idea.

  i'm going to disagree here, i never suggested "armv7a" was a
"machine" (in the sense of having a defining armv7a.conf file). i said
it was part of MACHINE_OVERRIDES, and therefore *would* be considered
a matching "machine" for the purposes of COMPATIBLE_MACHINE.

  as another example, there is no such machine as a "qoriq", but that
is considered a valid choice for COMPATIBLE_MACHINE since several
actual machine definition files do this:

  MACHINEOVERRIDES =. "qoriq:"

am i making sense?

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

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