Disable optimization of part of the code through CMAKE

Question

Hi, 
 A simple CMAKE question, somewhat regarding the zephyr build, but pretty essential for someone using JTAG to debug the application: 
 How does one disable optimization (-Os) for just a few files in the zephyr build? 
 
 I quicky tried a few things in the CMakeLists.txt: 
 
 - Adding a global target_compile_options(-O0) option => Builds the entire thing (incl zephyr) with O0, causing 200kB flash overflow 
 - Using target_compile_options(app PRIVATE -O0) => Leads to -O0 option, but this is overridden later in the compile line by -Os again, causing this to be negated 
 
 There must be a simple way to overrule Zephyr's overuling of the optimization compile option, and I am hoping somebody can quickly answer me on this. 
 
 Thanks!

Carl Richard · Accepted Answer

Hello, Arnout! I've asked internally about this, but there seems to be some difficulties with optimization flags passed from CMake as stated in this issue on the Zephyr RTOS GitHub. Have you tried the CONFIG_NO_OPTIMIZATIONS option in prj.conf? Edit: a colleague said that they have been using the following solution in a bit different context: add_library(set-app-flags INTERFACE)
target_compile_options(set-app-flags INTERFACE -O0)
target_link_libraries(app PRIVATE set-app-flags) Best regards, Carl Richard

Disable optimization of part of the code through CMAKE

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