building for embedded targets

[Gabriel Dos Reis]

On Tue, Jan 17, 2012 at 12:01 PM, Benjamin Kosnik <bkoz@redhat.com> wrote:
>
> Hey Gaby. Sorry for the delay.
>
>> I can''t remember what our general policy is regarding
>> builds that target embedded systems.  That is, if someone
>> configures with --target=avr, what are we supposed to
>> build?
>
> Dunno if that is a valid target, assuming aliases to avr-elf?

Hmm, I think AVR always uses ELF so I guess '-elf' is implied... I was
just copy-n-pasting target specifcation from AVR libc website

   http://www.nongnu.org/avr-libc/user-manual/install_tools.html

that is completed to avr-unknown-none.  (I -think- that is correct.)

I configured and built the compiler with --enable-languages='c,c++'.
While I have avr-g++, I could not find anything libstdc++ related
built.  I could not decide whether that was as "intended" or just a bug
in the configure script.   I would have expected to see things like
numeric_limits, but could not find it.  I am unsure about operator new
(AVR libc has malloc).


>
> Assuming this is a valid target, it will build all languages,
> all runtimes that are supported.
>
>>  Just libsupc++? or a bit of libstdc++ from
>> chapter 18?  Based on newlib or based on AVR libc?
>
> To get just libsupc++, use --disable-hosted-libstdcxx at configure time.

OK, I will try this and report back.

>
> To force newlib, use --with-newlib.
>
> Attached are my configure scripts for building arm-eabi and cris-elf,
> which are the targets I usually build when testing cross compiles.

Thank you!

-- Gaby