Re: [avr-libc-dev] mismatch of supported devices in avr-libc 1.7.0 and gcc-4.5.1

[Joerg Wunsch]

As Rolf Ebert wrote:

> I have just rebuilt a new compiler from pristine gcc-4.5.1
> sources. If I want to compile avr-libc-1.7.0 the compiler stops when
> building gcrt1.o for attiny2313a: unknown MCU specified.

The problem is that GCC doesn't exit with an error when encountering
an unknown -mmcu option, so the autoprobe implemented in avr-libc's
configure script doesn't work.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45261

This is /not/ a problem with GCC 4.5.x, the problem has always been
there.  The autoprobing only worked incidentally in the past when the
compiler and binutils have been in sync regarding the -mmcu options
they understood, so eventually the assembler flagged an error then,
which caused the compiler to give up.  Apparently here, your binutils
do understand the attiny2313a but your compiler doesn't, so the
autoprobing fails.

> Is there a way to either omit the new MCUs when building avr-libc or
> to add support for the new devices in gcc-4.5?

Three possible ways. ;-)

.  Fix bug #45261 with a local patch, see Andrew Pinski's comment #1
   in the bug tracker.

.  Add support for the attiny2313a -mmcu option with a local patch.

.  Remove support for the attiny2313a -mmcu option in your binutils
   with a local patch.

-- 
cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)