[Buildroot] [RFC] config cache

[Ulf Samuelsson <ulf@atmel.com>]

> Hi,
> 
> read ./TODO
> 
> Now i'd like to think loud about how to "implement" this.
> 
> preface:
> ========
> First, i'm not too happy (any more) with the naming of the variables
> TARGET_CONFIGURE_OPTS and TARGET_CONFIGURE_ARGS -- same for HOST.
> Both are variables and not really OPTS, as opposed to the cache
> option/argument.
> 
> Let me suggest that the CC= CFLAGS= settings live in (the respective
> CONFIGURE_ENV) variables.
> 
> Suggestions for the known cv_* vars? CONFIGURE_SETTINGS come to mind,
> but that's a bit long to type.. TARGET_CONFIGURE_PARAMS ?
> 
> cache:
> ======
> 
> Per PROJECT, we use (resp. i suggest to use a) *central* config.cache,
> via --config-cache=$(PROJECT_BUILD_DIR)/target_config.cache which is put
> into a TARGET_CONFIGURE_OPTS variable (we renamed the formerly _OPTS to
> something like PARAM that is passed *before* the
> $(PACKAGE_DIR)/configure script).
> 
> Since the advent of PROJECT one may even consider to build the
> autoconf'ed packages out-of-tree, i.e. unpack them in build_dir, step
> into project_dir/package/ and there do a
> $(PACKAGE_DIR)/configure $(TARGET_CONFIGURE_OTPS) && make
> 

One of the advantages of the PROJECT thing, is that you can share
the result of the build between projects.
Only packages which can be configured in different ways should be
built in the project_build_dir.


> We would end up with a stanza like (modulo naming of the variables):
> 
> (cd $(PROJECT_DIR)/$(PACKAGE_NAME) && \
> $(TARGET_CONFIGURE_ENV) \
> $(TARGET_CONFIGURE_PARAMS) \
> $(PACKAGE_DIR)/configure \
> $(TARGET_CONFIGURE_OPTS) \

Are you not using $(TARGET_CONFIGURE_OPTS) in a new meaning then.
I think in that case you should come up with a new name
to avoid bugs.


> --prefix=/usr \
> etc...
> )
> 


Best Regards
Ulf Samuelsson                ulf at atmel.com
Atmel Nordic AB
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