Re: [avr-gcc-list] EF_AVR_LINKRELAX_PREPARED bit in e_flags

[Georg-Johann Lay]

Vidya Praveen wrote:

> While we are on this topic, I was wondering if we should also introduce a bit in
> e_flags for -mshort-enums and add a compatibility check. Comments?

There are many other options that change the ABI and might lead to
incompatible objects and potentially wrong code if linked together:

-f[no-]unsigned-char
-f[no-]signed-char
-f[no-]unsigned-bitfields
-f[no-]pack-struct
-f[no-]short-double (not yet supported, i.e. defaults to -fshort-double)
-mint8

If you introduce a compatibility check then any usage of libgcc or
AVR-Libc will trigger a diagnose because these libraries are build
with the default ABI and none of these options is a multilib option.
That is: such an option is only helpful if no library support is used.
This es *very* uncommon because most application use at least startup
code and vectors.

Johann