[U-Boot] [PATCH 1/1] scripts/Makefile.lib: remove overridden target $(obj)/helloworld.so:

[Brüns, Stefan]

On Sonntag, 3. September 2017 17:26:43 CEST Heinrich Schuchardt wrote:
> On 09/03/2017 02:19 PM, Alexander Graf wrote:
> > On 03.09.17 08:17, Heinrich Schuchardt wrote:
> >> The target
> >> $(obj)/helloworld.so:
> >> exists twice in Makefile.lib.
> >> 
> >> If you add an echo command to each of the two recipes you get
> >> warnings like:
> >> 
> >> scripts/Makefile.lib:383: warning:
> >> overriding recipe for target 'drivers/power/battery/helloworld.so'
> >> scripts/Makefile.lib:379: warning:
> >> ignoring old recipe for target 'drivers/power/battery/helloworld.so'
> >> 
> >> This patch removes the obsolete target.
> >> 
> >> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> >> ---
> >> Hello Alex,
> >> 
> >> could you, please, review the change as it relates to EFI.
> > 
> > My Makefile foo isn't quite as good as it should be, but doesn't the
> > existing code simply add another dependency to the required build chain?
> 
> The target is overridden so why should the dependency be executed?
> 
> https://www.gnu.org/software/make/manual/html_node/Overriding-Makefiles.html
> says:
> "However, it is invalid for two makefiles to give different recipes for
> the same target. I guess this will be valid for a single makefile too."
> 
> If you think the dependency is necessary, I can add it to the remaining
> target. Is this what you prefer?

Note there is a difference between prerequisite and recipe - specifying a 
target multiple times without recipe adds the the prerequisite to the existing 
set, see

https://www.gnu.org/software/make/manual/html_node/Multiple-Targets.html#Multiple-Targets

---
foo: a

foo: b c

a:
        @echo "Creating prereq a"

%:
        @echo "Creating $@"
----

This tries to create the default target foo (first specified target), which 
has three prerequisites (a, b, c), which are run in parallel.

Kind regards,

Stefan