[Buildroot] [RFCv1 2/4] pkg-generic: add step_pkg_size global instrumentation hook

[Yann E. MORIN]

Arnout, All,

On 2014-06-24 18:36 +0200, Arnout Vandecappelle spake thusly:
> On 07/06/14 23:46, Thomas Petazzoni wrote:
> > This patch adds a global instrumentation hook that collects the list
> > of files installed in $(TARGET_DIR) by each package, and stores this
> > list into a file called $(BUILD_DIR)/<pkgname>.filelist. It can later
> > be used to determine the size contribution of each package to the
> > target root filesystem.
> > 
> > The only limitation is that if a file is installed by a package A, and
> > then overriden by a file from package B, the file will only be listed
> > in $(BUILD_DIR)/A.filelist as it is the first time we will see the
> > file.
> > 
> > Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> > ---
> >  package/pkg-generic.mk | 24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> > 
> > diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
> > index 5116ed9..069653e 100644
> > --- a/package/pkg-generic.mk
> > +++ b/package/pkg-generic.mk
> > @@ -55,6 +55,30 @@ define step_time
> >  endef
> >  GLOBAL_INSTRUMENTATION_HOOKS += step_time
> >  
> > +# Package size steps
> > +define step_pkg_size_start
> > +	echo "PKG SIZE START $(1)"
> > +	(cd $(TARGET_DIR) ; find . -type f) | sort > \
> > +		$(BUILD_DIR)/$(1).tmp_filelist_before
> > +endef
> > +
> > +define step_pkg_size_end
> > +	echo "PKG SIZE END $(1)"
> > +	(cd $(TARGET_DIR); find . -type f) | sort > \
> > +		$(BUILD_DIR)/$(1).tmp_filelist_after
> > +	diff -u $(BUILD_DIR)/$(1).tmp_filelist_before $(BUILD_DIR)/$(1).tmp_filelist_after | \
> > +		grep '^\+\./' | sed 's%^\+%%' > $(BUILD_DIR)/$(1).filelist
> > +	$(RM) -f $(BUILD_DIR)/$(1).tmp_filelist_before \
> > +		$(BUILD_DIR)/$(1).tmp_filelist_after
> > +endef
> > +
> > +define step_pkg_size
> > +	$(if $(filter install-target,$(2)),\
> > +		$(if $(filter start,$(1)),$(call step_pkg_size_start,$(3))) \
> > +		$(if $(filter end,$(1)),$(call step_pkg_size_end,$(3))))
> > +endef
> > +GLOBAL_INSTRUMENTATION_HOOKS += step_pkg_size
> 
>  Since these instrumentation steps are relatively expensive (especially for
> large builds with many small packages), I would prefer to only enable this after
> setting some environment variable or config option or similar.

Ideally, I would like an entry in the menuconfig (probably in the "build
options" sub-menu):

    [*] Graphs and intrumentation  --->
        *** Graphs ***
        [ ] Packages' installed size
        [ ] Packages' build time
        [ ] Packages' dependencies
        [ ] Global dependencies
        *** Instrumentation ***
        [ ] Check RPATH
        [ ] Check for overwritten files

Thus, all relevant information would be automatically generated. Of
course, some can be generated on-demand (eg. the dependencies graphs),
while others 

(Note: the rpath check I'm currently working on, and the overwriting
check would be relatively easy to implement I guess; but that's just an
example.)

Regards,
Yann E. MORIN.

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