rtems-gcc linker warnings

[joel at OARcorp.com (joel at OARcorp.com)]

On Thu, 15 Jul 1999, Ralf Corsepius wrote:

> Hi,
> 
> With some-rtems toolschains, freshly build from binutils-2.9.1.0.25,
> newlib-1.8.1 and egcs-1.1.2, all with latest rtems-patches applied, I
> get linker warnings when linking an empty main function:
> 
> #cat hello.c
> int main( )
> {
>   return 1;
> }
> 
> #i386-rtems-gcc -Wall -o hello hello.c
> /opt/rtems/i386-rtems/bin/ld: warning: cannot find entry symbol _start;
> defaulting to 08048084
> #hppa1.1-rtems-gcc -Wall -o hello hello.c
> /opt/rtems/hppa1.1-rtems/bin/ld: warning: cannot find entry symbol
> $START$; defaulting to 00002000
> #sparc-rtems-gcc -Wall -o hello hello.c
> /opt/rtems/sparc-rtems/bin/ld: warning: cannot find entry symbol _start;
> defaulting to 00010090
> #mips64orion-rtems-gcc -Wall -o hello hello.c
> /opt/rtems/mips64orion-rtems/bin/ld: warning: cannot find entry symbol
> _start; defaulting to 0000000000400020
> 
> #sh-rtems-gcc -Wall -o hello hello.c
> #m68k-rtems-gcc -Wall -o hello hello.c
> #i960-rtems-gcc -Wall -o hello hello.c
> 
> Note: This happens without having rtems installed and therefore also
> happens silently during the configuration of  RTEMS when bootrapping
> RTEMS (cf. rtems/config.log) and can potentially affect configure script
> checks (Though I did not notice any, yet).
> 
> AFAIS all compilers not showing this problem are COFF, while all other
> seem to be ELF. Therefore I guess that this might be related to the
> switch to elf (newlib + crt0 ?).

crt0.c in newlib is supposed to satisfy all the symbols expected.  So if
_start is not being defined, then newlib/libc/sys/rtems/crt0.c needs to
define it.  Will that take care of the warning?

I know the resulting executable is useless but we knew that all along. :)

--joel