Compile modules selectively in release vs debug to optimize flash usage in nRF52840

RE: Compile modules selectively in release vs debug to optimize flash usage in nRF52840

Håkon Alseth — Thu, 09 Sep 2021 14:46:23 GMT

Hi Johan,

Thanks for updating the case. I did not find this option when looking myself, very good to see that its possible to do this in a portable way!

Kind regards,

Håkon

RE: Compile modules selectively in release vs debug to optimize flash usage in nRF52840

Johan — Thu, 09 Sep 2021 08:16:45 GMT

Ok thanks Håkon.

I got this from Zephyrs discord channel help on Nordic subjects.

yes, that is possible. You can place dedicated compile options on a Zephyr library (the app library is a Zephyr library). For example in you toplevel CMakeLists.txt file you may do:

find_package(Zephyr ...)
project(my_project)
 
zephyr_library_compile_options(-O0)
target_sources(app ...)

That will make that particular library compile with -O0 while the rest of Zephyr compiles with the optimization you have specified in prj.conf / Kconfig(edited)

zephyr/Kconfig.zephyr

https://github.com/zephyrproject-rtos/zephyr/blob/main/Kconfig.zephyr#L275-L309

Docs / Latest » choice: Optimization level

https://docs.zephyrproject.org/latest/reference/kconfig/choice_536.html

prj.conf

tejlmand —
When using in prj.conf, remember to put CONFIG_ first, like: CONFIG_SIZE_OPTIMIZATIONS=y

RE: Compile modules selectively in release vs debug to optimize flash usage in nRF52840

Håkon Alseth — Wed, 08 Sep 2021 12:51:04 GMT

Hi Johan,

[quote user=""]

For example:

- zephyr modules -> release compilation

- nordic modules -> release compilation

- our application src folder - debug compilation as we need to debug it - or be able to select which folders in that src-folder to compile as debug vs release mode.

[/quote]

The only thing that comes to mind is to force GCC to set a specific optimize level on your sources, via the #pragma directive:

https://gcc.gnu.org/onlinedocs/gcc/Function-Specific-Option-Pragmas.html

You can guard that pragma + push/pop lines with a if defined(some_symbol). Note that this is not a portable solution.

Kind regards,

Håkon