Executable size

[Thomas Doerfler (nt)]

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Leon,

just guessing:
- - And RTEMS has been split into many small modules: one module per
function instead of one module per subsystem. The idea is that the
linker can then pick in those modules that are required, without unused
code which in turn would pull in additional unused modules.

- - Many RTEMS functions are implemented as inline functions now, in the
respective headers files.

If you compile RTEMS with "-fkeep-inline-functions", then for EACH of
the many RTEMS modules will carry a local copy of ALL inline-functions
visible in its header files.

So you will end up with 100-200 local copies of the inlined functions,
and this may really bloat the overall executable size.

So I don't see a reason for the switch "-fkeep-inline-functions" and I
would guess that it is responsible for your code size increase.

wkr,
Thomas.

Leon Pollak schrieb:
> Thanks for your responses.
> Below is the more detailed study.
> 
> 1. Joel, you are right - the optimized version of application and RTEMS is 
> even a bit smaller (about 5%).
> 
> 2. Debug version (of application & RTEMS) still is 4 times bigger.
> This is the 'size' report for 4.8.0:
>   text    data     bss     dec     hex filename
> 1093064   20092  298832 1411988  158b94 VDTS
> 
> And this is the 'size' for 4.9.3:
>    text    data     bss     dec     hex filename
> 4050468   14405  298224 4363097  429359 VDTS
> 
> All the compilation parameters are exactly the same for both cases, except 
> that RTEMS IN BOTH CASES(!) is compiled for debug with:
> CFLAGS_OPTIMIZE_V=-O0 -g -ggdb -fkeep-inline-functions
> for optimized with:
> CFLAGS_OPTIMIZE_V=-O4 -g -ggdb -fno-keep-inline-functions
> 
> Thanks again.


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Thomas Doerfler           Herbststrasse 8
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