selecting mandatory modules for a given sample program

[jmfriedt]

I am executing Zephyr on the Zynq of a Red Pitaya as described at https://github.com/master-elise/zephyr_redpitaya.

I would like to avoid downloading the 9 GB of modules and HAL most of which will not be used on this platform. I was pleased to see that I could compile blinky and hello_world with only the basic installation and external cross-compilation toolchain after adding CMSIS for the ARM libraries. However, when compiling the dining philosophers demonstration, I could compile and got a binary, but it would not execute. Only by west update to download all modules did I get a functional executable. So my questions:

1/ how can a binary be generated that would not execute? I would expect some error at the linker stage if some functions are missing

2/ how can I identify which module is needed for compiling and executing a given sample program? I tried adding the most obvious (cmsis_6 openthread picolibc) but these were not enough to reach a functional executable, so I ended up downloading all 9 GB worth of modules and got the example running, knowing many of these modules are not used.

Thanks.