[Buildroot] [PATCH v2 2/3] package: fix generic extract target for top-level parallel make

Arnout Vandecappelle arnout at mind.be
Thu Aug 22 15:59:04 UTC 2013

On 22/08/13 09:44, Fabio Porcedda wrote:
> On Wed, Aug 21, 2013 at 9:24 PM, Arnout Vandecappelle <arnout at mind.be> wrote:
>> On 18/07/13 11:12, Fabio Porcedda wrote:
>>>    $(1)-patch:           $(1)-extract $$($(2)_TARGET_PATCH)
>>> -$(1)-extract:          $(1)-source \
>>> -                       $$($(2)_TARGET_EXTRACT)
>>> +$$($(2)_TARGET_EXTRACT):       $$($(2)_TARGET_SOURCE)
>>> +$(1)-extract:                  $$($(2)_TARGET_EXTRACT)
>>>    $(1)-depends:         $$($(2)_DEPENDENCIES)
>>   On second observation, I don't really like this change, because it makes
>> the extract and patch parts asymmetrical with the others. I would prefer one
>> patch that changes it for all the targets. But then, the behaviour does
>> change, because rebuilding one package will also trigger a rebuild of the
>> packages that depend on it. Which may be a good thing, of course...
> Do you mean a single patch that changes all the targets? IMHO the
> patch becomes too complex, but if is the preferred way i'm fine with
> that.

  Yes. I estimate it will modify about 50 lines, so I don't see a problem.

> To be able to change the others targets i need to add stamp file for
> every target inside $$($(2)_DEPENDENCIES,
> i need to do that because a file cannot depends on a non existing file.

  That's not true. Take the following Makefile:

	touch $@

%.extract: %.source
	touch $@

%.config: %.extract
	touch $@

%.build: %.config
	touch $@

X_DEPS = y z

x.config: $(X_DEPS)
x: x.build

Y_DEPS = z

y.config: $(Y_DEPS)
y: y.build

z.config: $(Z_DEPS)
z: z.build

.PRECIOUS: %.source %.extract

  Type 'make x', and all the build, config, extract, source files will be 
touched in the right order.

  The .PRECIOUS line may not be needed in practice, I added it here 
because there are no explicit rules involving *.source and *.extract, 
therefore these files will be deleted after a successful build.

> If there is any chance that such modification is going to be accepted
> i restart to work on the second part.
>>   Also, I think it would be nicer / clearer to put these dependencies in the
>> %-rules at the top of the file, rather than specifying them per package.
> Do you mean to put together all those rules between the %-rules
> section and inner-generic-package function?
> or to scatter them in the %-rules section?

  No, I mean to do it like the example above: use the % rules to specify 
the dependencies between the stamp files, rather than an explicit rule 
for each package.


> Best regards

Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
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