[Buildroot] [PATCH RFC] core: enable per-package log files

[Yann E. MORIN]

Thomas, Arnout, Anisse, All,

On 2017-10-18 13:36 +0200, Thomas Petazzoni spake thusly:
> On Wed, 18 Oct 2017 12:57:30 +0200, Arnout Vandecappelle wrote:
> >  As I said a couple of times already, I don't think we should enforce -Orecurse.
> 
> As I replied in another e-mail, I disagree :)
> 
> >  About the BR2_PARALLEL_BUILD option, it may be useful, but for the time being I
> > would continue asking the user to remove the .NOTPARALLEL line.

Eventually, when everything is fully parallel-safe, I believe we will
want to remove BR2_JLEVEL altogether, and let users directly call
"make -jN".

As for the -O option, it all depends on the oldest make we are supposed
to support. It appeared only in make 4.0, released in October 2013.

So I think we'll have to come up with an alternative solution (and I am
sad that we do, I would have prefered we require 4.0, but it is not old
enough :-/ ).

However, I'll repeat my position: having top-level parallel build (TLP)
is important. If we can't find a viable, simple and maintainable
solution, then we should just ignore the problem and still implement
TLP.

I am not much happy with any of the external wrapper, because it is
relatively fragile, and we have to use it everywhere we need to write a
make rule (which is not a package, fs, or bootloader CMDS).

For example, we also need to use it for:

  - the step_start and step_end hooks
  - the intermediate commands [0] [1]
  - ech commands in the finalise-target, legal-info and all similar ones
  - and I suspect countless other locations...


[0] for example, it is needed for the for-loop there:
   package/pkg-generic.mk:
   145 $(BUILD_DIR)/%/.stamp_downloaded:
   146 »   $(foreach hook,$($(PKG)_PRE_DOWNLOAD_HOOKS),$(call $(hook))$(sep))
   147 # Only show the download message if it isn't already downloaded
   148 »   $(Q)for p in $($(PKG)_ALL_DOWNLOADS); do \
   149 »   »   if test ! -e $(DL_DIR)/`basename $$p` ; then \
   150 »   »   »   $(call MESSAGE,"Downloading") ; \
   151 »   »   »   break ; \
   152 »   »   fi ; \
   153 »   done
   154 »   $(foreach p,$($(PKG)_ALL_DOWNLOADS),$(call DOWNLOAD,$(p))$(sep))
   155 »   $(foreach hook,$($(PKG)_POST_DOWNLOAD_HOOKS),$(call $(hook))$(sep))
   156 »   $(Q)mkdir -p $(@D)
   157 »   $(Q)touch $@


[1] for example, it is needed for each of mkdir, chmod and touch there:
   package/pkg-generic.mk:
   166 $(BUILD_DIR)/%/.stamp_extracted:
   167 »   @$(call step_start,extract)
   168 »   @$(call MESSAGE,"Extracting")
   169 »   $(foreach hook,$($(PKG)_PRE_EXTRACT_HOOKS),$(call $(hook))$(sep))
   170 »   $(Q)mkdir -p $(@D)
   171 »   $($(PKG)_EXTRACT_CMDS)
   172 # some packages have messed up permissions inside
   173 »   $(Q)chmod -R +rw $(@D)
   174 »   $(foreach hook,$($(PKG)_POST_EXTRACT_HOOKS),$(call $(hook))$(sep))
   175 »   @$(call step_end,extract)
   176 »   $(Q)touch $@


Regards,
Yann E. MORIN.

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