GCC configure problem with 32-bit stuff on x86_64

[Kai Ruottu]

Chris Lu wrote:
> On 11/14/05, Kai Ruottu <karuottu@mbnet.fi> wrote:
> 
>>You didn't tell your "x86_64 system" type but let's guess it being
>>Linux, not FreeBSD, NetBSD or something else...
> 
> You guessed correctly, it is a Linux system. Sorry about that...
> 
>>Just (pre)install the 32-bit C libraries, they should be in '/lib'
>>and '/usr/lib' in the Linux case. The default 64-bit libs then are
>>normally in '/lib64' and '/usr/lib64'.
> 
> For some reason I have */lib for the 64-bit libs, */lib32 for 32-bit,
> and */lib64 symlinked to */lib.

  The FSF GCC sources seem to expect the Linux/x86_64 installations
to have the default 64-bit stuff in '*/lib64' and the 32-bit stuff
in '*/lib', so you have a problem to solve with this. What kind of
Linux/x86_64 puts its libraries this way?

  Anyway the place where the default settings for GCC are told, is
the 'gcc/config/i386/t-linux64', a clip from its beginning :

----------------------- clip ------------------------------------
# On x86-64 we do not need any exports for glibc for 64-bit libgcc_s,
# override the settings
# from t-slibgcc-elf-ver and t-linux
SHLIB_MAPFILES = $(srcdir)/libgcc-std.ver \
		 $(srcdir)/config/i386/libgcc-x86_64-glibc.ver

MULTILIB_OPTIONS = m64/m32
MULTILIB_DIRNAMES = 64 32
MULTILIB_OSDIRNAMES = ../lib64 ../lib
----------------------- clip ------------------------------------

  So changing the last row to be:

MULTILIB_OSDIRNAMES = ../lib ../lib32

should change the default behaviour to be for your 'custom'
Linux/x86_64... At least I think this being the place for setting
those 'operating system directory names'.

> $ x86_64-unknown-linux-gnu-gcc-4.0.2 -o hello -m32 -L/lib32/ -v hello.c
<snip>
>  /usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.0.2/collect2
> --eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -o hello
> /usr/lib/../lib/crt1.o /usr/lib/../lib/crti.o
> /usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.0.2/32/crtbegin.o
> -L/lib32/ -L/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.0.2/32
> -L/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.0.2
> -L/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.0.2/../../../../lib
> -L/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.0.2/../../..
> -L/lib/../lib -L/usr/lib/../lib /tmp/cc03Pm1W.o -lgcc --as-needed
> -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed
> /usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.0.2/32/crtend.o
> /usr/lib/../lib/crtn.o

Yes, with the '-m32' the '*/lib' stuff is tried to be used... Without
it you should get the '*/lib64' in those '-L' options with your current
settings. And changing what I suggested, restarting the build (it should
see the target-makefile-fragment changed and rebuild what this change
requires), the '*/lib' stuff should be searched as default and '*/lib32'
stuff with the '-m32'...