Re: cross-compiling v7.0.7

[Andrew Johnson via Tech-talk <tech-talk at aps.anl.gov>]

Hi Pierrick,

On 6/15/23 6:07 AM, Pierrick M Hanlet via Tech-talk wrote:

Something broke, or I missed new instructions in building the modules in 
v7.0.7 for cross-compiled platforms.
I'm building for several platforms.  The host build is fine, but when 
the cross-compiled platforms start building
a new RELEASE.linux-x86_64.local is created with "EPICS_BASE = ", i.e. 
empty.  I did not experience this with
v7.0.5.

Hopefully the fix should be to just delete that file and run 'make' again in that directory, but if you have a more complex local build process (e.g. if you're building on multiple host arch's) that might need some modifications. How were you doing the cross-builds?

Getting the build rules right for generating the modules/RELEASE.<host>.local file was tricky, and there were some changes made to them between 7.0.5 and 7.0.7:

$ git log R7.0.5.. -- configure/RULES_MODULES
commit 098ee6c063c25c3b4483d7d5a0b6c8c6d8d17769
Author: Andrew Johnson <anj at anl.gov>
Date:   Sat Sep 3 10:59:26 2022 -0500

    Oops: Fix to RULES_MODULES

commit efc7cbaf7f93c1bc58f98b30b9d20a27bc0a7f91
Author: Andrew Johnson <anj at anl.gov>
Date:   Fri Sep 2 14:10:27 2022 -0500

    Build system fixes related to INSTALL_LOCATION
    
    * The build can't descend into external submodules when there is no
    configure/RULES_TOP file present in $(INSTALL_LOCATION).
    * Recreate modules/RELEASE.<host>.local if configure/CONFIG_SITE or
    configure/CONFIG_SITE.local have changed.
    * Move the distclean of modules/RELEASE.<host>.local to RULES_TOP
    * Several comment and white-space changes

commit 191ff137f17eecde9e836f0f9aeaec5eecb73b24
Author: Andrew Johnson <anj at anl.gov>
Date:   Wed Nov 24 21:58:32 2021 -0600

    configure: Use GNU Make's abspath instead of fullPathname.pl
    
    Add new INSTALL_ABSOLUTE variable, remove duplicates.

There are some comments at the top of the RULES_MODULES file but they were mostly intended for other applications that want to adopt the submodules scheme (the motor record uses it too).

- Andrew

-- 
Complexity is free, it's Simplicity that takes work.