Gcc on Blue Gene / Q

[Kai Ruottu]

Fatih Ertinaz kirjoitti 22.2.2018 klo 17:55:

> I decided to try a different version; gcc-5.2.0 which seems to fail at
> the exact step:
> make[2]: Leaving directory
> `......../gcc/gcc-5.2.0-work/powerpc64-bgq-linux/libgcc'
> /bin/sh: line 3: cd: powerpc64-bgq-linux/libstdc++-v3: No such file or directory
> make[1]: *** [install-target-libstdc++-v3] Error 1

Probably the build simply didn't produce 'target-libstdc++-v3' at all 
because there
weren't any target headers and libraries available.

> One quick question:
>>>                --target=powerpc64-bgq-linux \
>>>                --host=powerpc64-linux-gnu \
>>>                --build=powerpc64-linux-gnu \
>> Those host and build values look wrong.
> Why?

If the $target value is different from the $host value, then one is 
trying to make
a crosscompiler, not a native compiler!  A crosscompiler doesn't search 
the target
stuff in the native places, usually '/usr/include' and '/usr/lib'. But 
as default
searches them in the '$prefix/$target/include' and '$prefix/$target/lib' 
unless
one has used the '--with-sysroot=$sysroot' to point where the target 
stuff is,
copied from the native $target system.

 > checking whether the ...../gcc/gcc-5.5.0-work/./gcc/xgcc
 > -B/..../gcc/gcc-5.5.0-work/./gcc/
 > -B/..../gcc-5.5.0/powerpc64-bgq-linux/bin/
 > -B/..../gcc-5.5.0/powerpc64-bgq-linux/lib/
 > -isystem /..../gcc-5.5.0/powerpc64-bgq-linux/include
 > -isystem /..../gcc-5.5.0/powerpc64-bgq-linux/sys-include

Here were the search paths but that ''/..../gcc-5.5.0/' doesn't look 
sane at all as
the wanted $prefix. With a native GCC one usually uses '--prefix=/' or 
the default
'--prefix=/usr/local' when leaving the '--prefix=<something>' totally 
away from the
GCC configure command...

I will not try more to tell why the second place for the headers, the 
"system headers" :
'/..../gcc-5.5.0/powerpc64-bgq-linux/sys-include' is there. Only that it 
is a remnant
from the dark past when there were systems which had new headers, 
"system specific",
not only the "standard" posix ones. Usually they were the GUI / API 
headers like in
Windows, X11, BeOS etc systems but when the native systems didn't have a 
separate
place for them (like '/usr/sys-include'), neither a crosscompiler put 
them to the
'$prefix/$target/sys-include' although it was ready for them. Instead 
some believed
that it was the place for the standard posix headers, not the 
'$prefix/$target/include'.
This then caused a horrible mess which the '--with-sysroot=$sysroot' 
solved, one just
put the native headers into the $sysroot just in the same way as they 
were in the
native sysroot '/'....

Ok, you should use :

--build=powerpc64-bgq-linux \
--host=powerpc64-bgq-linux \
--target=powerpc64-bgq-linux \

or barely the '--host=powerpc64-bgq-linux' or leave them totally away, then
the build/host/target triplets will be 'guessed' via the 'config.guess'
script in the main GCC source directory...