Tracking Firmware Code Size | Interrupt

Blog
5

What strategy would you follow?

Our long-term goal would be to have a map of occupation of the memory regions that informs us how much the different compile units fill.

Under the hood, arm-none-eabi-size is just walking through the ELF sections (output you would see from arm-none-eabi-readelf -S <your_file.elf> and inspecting the sh_flags in the section header. The rules it uses are:

  • If the section is not allocated (SHF_ALLOC == 0), don’t count it
  • if the section is executable (SHF_EXECINSTR == 1) or the section is not writable (SHF_WRITE == 0), add to text count
  • If the section has no data (SHT_NOBITS == 1), add it to the bss count else add it to the data count

You could use pyelftools to load the elf and compute text/data/bss sums for each memory region you want using those rules.