Why this small code doesn't fit in flash? (STM32)

maxgerhardt · June 5, 2023, 8:08pm

Hmm two thoughts:

Are you linking against nanolibc by passing --specs=nano.specs as linker flags in your extra_script.py? Otherwise you’re getting a really big C library.
Do you overwrite functions like __cxa_pure_virtual so that their default code might not want to generate huge code and things like backtrace unwinding?

arduino/ArduinoCore-megaavr/blob/5e639ee40afa693354d3d056ba7fb795a8948c11/cores/arduino/abi.cpp#L19-L35


      
          #include <stdlib.h>
          
          
extern "C" void __cxa_pure_virtual(void) __attribute__ ((__noreturn__));
          extern "C" void __cxa_deleted_virtual(void) __attribute__ ((__noreturn__));
          
          
void __cxa_pure_virtual(void) {
            // We might want to write some diagnostics to uart in this case
            //std::terminate();
            abort();
          }
          
          
void __cxa_deleted_virtual(void) {
            // We might want to write some diagnostics to uart in this case
            //std::terminate();
            abort();
          }