4.6 Code Size Report
The memory summary produced by AVR-GCC (and hence by the MPLAB X IDE when AVR-GCC is selected as
the compiler tool) shows a lower-than-actual Flash usage. In
particular, it does not consider the .rodata
section (on devices with memory-mapped flash) as well as any
user defined sections containing code or read-only data. The
MPLAB XC8 compiler will produce a more accurate summary of Flash
memory used than AVR-GCC when building the same project. If you
are comparing memory usage between the toolchains, ensure you
check the map file to determine the exact size of the all
sections used by your program.