Help with ppc-linux cross

[Kai Ruottu]

Brendan Simon wrote:

> find some runtime libs.  eg. I used the yellowdog linux glibc libraries which were
> pointed out to me by Kai Ruottu.  Here are his instructions.
> 
> http://www.yellowdoglinux.com/

   < clip >

> Probably need to fix the "-dynamic-linker" statement in the specs file
> ($prefix/lib/gcc-lib/$target/$egcs-version/specs) to be "-dynamic-linker
> $prefix/$target/lib/ld.so.1".

 This is wrong... The '--dynamic-linker ....' shouldn't be touched! It tells 
where to found the file at runtime on a ppc-linux machine. This info will be 
recorded into the executable:

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E:\usr\local\samples>strings tst_linux-gnu.x | less
/lib/ld-linux.so.2
__gmon_start__
libc.so.6
_DYNAMIC
_GLOBAL_OFFSET_TABLE_
_fini
_init
__libc_init_first

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Although also this may help to find the file at link-time, the right option 
would be using the '-rpath-link $prefix/$target/lib', where the $prefix and 
$target are set to tell where the 'dynamic-linker' file is at link-time...

These things were new to me when I wrote the stuff, if one reads the messages
since a couple a weeks in this list, about Linux, AIX and Solaris target tools,
the '-rpath' (set the link-time/runtime search paths) and the '-rpath-link' 
(set the search path for the linked-libraries, inside a shared library).

 Ian Lance Taylor wrote:

>> I actually don't think --rpath-link is needed on AIX.  On ELF, the
>> --rpath-link option is used because one shared library can refer
>> directly to another, and the linker wants to try to track down the
>> referenced shared library in order to give appropriate warnings if
>> some shared library or symbol is not defined.

 Many thanks to Ian Lance Taylor for clarifying this to all of us!
The 'dynamic-linker' file is referenced in the Linux-gnu 'libc.so',
here is the 'x86-linux-gnu' target one:

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E:\usr\local\i586-linux-gnu\lib>strings libc.so | grep ld-linux
ld-linux.so.2
/lib/ld-linux.so.2
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 Without the '-rpath-link', this would be searched in the current
directory and in '/lib'. Of course one can think to install it to
'/lib' in the x86-linux-gnu host, the 'ppc-linux-gnu' one is named
differently as 'ld.so.2' or something, but keeping all the target
stuff in one place would be nicer...

Cheers, Kai

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