GCC as m68k cross-compiler

Question

I am trying to recompile binutils and GCC as a cross-compiler for m68k architecture. I am following these instructions:

http://darkdust.net/writings/megadrive/crosscompiler

However, the process keeps failing on one part or another. I have tried with binutils 2.16.1 and gcc 3.4.6, binutils 2.15 and gcc 3.4.2 and binutils 2.15 and gcc 3.4.6.

This last attempt fails when running "make" on gcc, after making and installing binutils. It gives the following error:

gcc   -g -O2 -DIN_GCC -DCROSS_COMPILE  -W -Wall -Wwrite-strings -Wstrict-
prototypes -Wmissing-prototypes -pedantic -Wno-long-long    -DHAVE_CONFIG_H    
-I. -I. -I../../gcc-3.4.2/gcc -I../../gcc-3.4.2/gcc/. -I../../gcc-
3.4.2/gcc/../include   \
-DTARGET_MACHINE=\"m68k-coff\" \
-c ../../gcc-3.4.2/gcc/collect2.c -o collect2.o

In file included from /usr/include/fcntl.h:289:0,
             from ../../gcc-3.4.2/gcc/system.h:214,
             from ../../gcc-3.4.2/gcc/collect2.c:30:

In function ‘open’,
inlined from ‘collect_execute’ at ../../gcc-3.4.2/gcc/collect2.c:1535:20:
/usr/include/x86_64-linux-gnu/bits/fcntl2.h:50:4: error: call to 
‘__open_missing_mode’ declared with attribute error: open with O_CREAT or 
O_TMPFILE in second argument needs 3 arguments
__open_missing_mode ();
^
Makefile:1364: recipe for target 'collect2.o' failed
make[1]: *** [collect2.o] Error 1
make[1]: Leaving directory '/home/gabriel/src/gcc-build/gcc'
Makefile:23339: recipe for target 'all-gcc' failed
make: *** [all-gcc] Error 2

I don't expect to fix this error, but does anyone know of a combination of binutils and gcc release that work? Should I be using a certain version of gcc to recompile gcc successfuly?

Thanks for any insight you may have on this!

EDIT:

My linux has GCC 5.4.0 so I just downloaded the 5.4.0 source to try and rebuild that for m68k cross-compiling. I now get the following error when running "make" on the gcc source:

*** Configuration m68k-unkown-coff not supported

What could be the cause of this? Is it because I need an older version of GCC? (the binutils version i'm using definately supports the m68k target). The tutorial I'm using always defines "--target=m68k-coff", should that instead be "--target=m68k-unkown-coff"?

EDIT 2:

So I tried compiling for m68k-elf but now I get this error:

checking for m68k-elf-gcc... /home/gabriel/src/gcc-build/./gcc/xgcc -B/home/gabriel/src/gcc-build/./gcc/ -B/opt/m68k/m68k-elf/bin/ -B/opt/m68k/m68k-elf/lib/ -isystem /opt/m68k/m68k-elf/include -isystem /opt/m68k/m68k-elf/sys-include
checking for suffix of object files... configure: error: in `/home/gabriel/src/gcc-build/m68k-elf/libgcc':
configure: error: cannot compute suffix of object files: cannot compile

I ran download_prerequisites before building so it should not be a problem with the MPC library. Any idea how to move on? I need assembler only so I don't mind what the format of the object files is. Thanks!

Answer 1

I used to do pretty much what you are doing right now.

My advice is to use crosstool-ng (http://crosstool-ng.github.io), as it does pretty much everything in an automated manner.

If you are studying m68k assembly, I used to host a modified version of gcc-explorer by Matt Godbolt (https://godbolt.org/). You can find a runnable docker image here (https://hub.docker.com/r/esantoro/acso-explorer/) and some more details here (https://znpy.wordpress.com/2017/05/08/decommisioning-acso-explorer-santoro-tk/)

Hope it helps,

znpy