Difficulty cross-compiling

[William Tracy (wtracy)]

Hello,

 

I'm trying to cross-compile a library that uses GNU Autotools (Google
Coredumper, to be specific) for PPC using the MontaVista tool chain. The
sequence of commands I'm following is:

 

$ ./configure --host=ppc CC=/path/to/gcc CXX=/path/to/g++

$ make

$ [next step would normally be "make install"]

 

For a normal (not cross-compile) configuration, issuing "make" causes a
.libs/ directory to be generating containing .a, .o, and .so files (and
variants thereof). When I cross-compile for PPC, the directory is
created and populated with a .a file, but no .so files. I can see .o and
.lo files being generated, so the code *is* getting compiled, but the
linking stage gets skipped. When I review the make output, there are no
error messages or warnings-the commands related to the .so files are
simply missing.

 

I've tried additionally manually specifying paths for the other
components of the GNU toolchain (linker, assembler, etc.) and, at the
suggestion of the people on the CLFS mailer, I've tried running
./configure with -enable-shared="yes" -enable-static="no". None of these
suggestions have helped.

 

*Summary*: When I try to cross-compile, make mysteriously and silently
skips one or more parts of the build. (If I build for the same
architecture, it works fine.)

 

I've tried diff-ing the Makefiles generated by ./configure for the
different architectures, and they look the same (other than the paths to
the compiler executables being different). I've also tried grepping the
Makefiles for the relevant commands that I see in the output; I get no
matches in either Makefile, so Autotools is doing something arcane here.

 

Any input would be appreciated.

 

---

William Tracy

 

[John Calcote-2]

Hi William,

On 10/12/2009 12:26 PM, William Tracy (wtracy) wrote:

> I'm trying to cross-compile a library that uses GNU Autotools (Google
> Coredumper, to be specific) for PPC using the MontaVista tool chain. The
> sequence of commands I'm following is:
>
> $ ./configure --host=ppc CC=/path/to/gcc CXX=/path/to/g++
>
> $ make
>
> $ [next step would normally be "make install"]
>
> For a normal (not cross-compile) configuration, issuing "make" causes a
> .libs/ directory to be generating containing .a, .o, and .so files (and
> variants thereof). When I cross-compile for PPC, the directory is
> created and populated with a .a file, but no .so files. I can see .o and
> .lo files being generated, so the code *is* getting compiled, but the
> linking stage gets skipped. When I review the make output, there are no
> error messages or warnings-the commands related to the .so files are
> simply missing.
>    

You don't state your target OS, only the CPU architecture, and I'm not
familiar with MontaVista, so I'm not sure I'm helping here. But if your
target platform is AIX, or anything like it, you may be experiencing
AIX-library-naming-difference syndrome - a sense of disorientation
associated with not being able to find your AIX shared libraries after
building. ;-)

The default library extension for some versions of AIX is .a. These .a
files contain the equivalent of standard Unix static /and dynamic/
libraries. Thus, on AIX/PPC, .a files are dynamically loaded just like
.so files on Solaris or Linux. The .a files also contain the static
objects linked into a binary when static linking is requested.

Regards,
John

[William Tracy (wtracy)]

This is a semi-embedded Linux system that I am trying to build for.

MontaVista is a Linux distribution that also provides a cross-compiling
toolchain--their own builds of the GNU toolchain, really. Their build
follows their own interesting naming convention, which isn't making this
simpler. >_<

Thanks for the reply, though.

---
William Tracy

-----Original Message-----
From: John Calcote [mailto:john.calcote@...]
Sent: Monday, October 12, 2009 12:00 PM
To: William Tracy (wtracy)
Cc: automake@...
Subject: Re: Difficulty cross-compiling

You don't state your target OS, only the CPU architecture, and I'm not
familiar with MontaVista, so I'm not sure I'm helping here. But if your
target platform is AIX, or anything like it, you may be experiencing
AIX-library-naming-difference syndrome - a sense of disorientation
associated with not being able to find your AIX shared libraries after
building. ;-)

The default library extension for some versions of AIX is .a. These .a
files contain the equivalent of standard Unix static /and dynamic/
libraries. Thus, on AIX/PPC, .a files are dynamically loaded just like
.so files on Solaris or Linux. The .a files also contain the static
objects linked into a binary when static linking is requested.

Regards,
John

[Ralf Corsepius-2]

On 10/12/2009 08:26 PM, William Tracy (wtracy) wrote:

> Hello,
>
>
>
> I'm trying to cross-compile a library that uses GNU Autotools (Google
> Coredumper, to be specific) for PPC using the MontaVista tool chain. The
> sequence of commands I'm following is:
>
>
>
> $ ./configure --host=ppc CC=/path/to/gcc CXX=/path/to/g++

Normally, a cross-toolchain's tools are called <host>-<tool>

i.e.
* one normally doesn't have to set CC nor CXX.

* the value being passed to --host is the tool prefix and therefore must
match the tool-prefix being used by your toolchain.

Ralf

[Harlan Stenn-5]

William,

I did a lot of what you are talking about when I was there - do you have
access to any of the ATC stuff?

H

[William Tracy (wtracy)]

Probably not, but I could poke around and see.

I suspect I ultimately need to grab someone from our build team and get
them to escalate this to MontaVista; I thought I'd try on a few mailers
first and see if I might get a response without going through multiple
layers of indirection. :-P

Ralph: MontaVista's binaries seem to follow the naming convention
<arch>-<variant>-linux-gnu-<app>. I haven't figured out yet what flags
to pass to ./configure to make it work, so I've just been explicitly
specifying which binaries to use. :-P

---
William Tracy

-----Original Message-----
From: Harlan Stenn [mailto:stenn@...]
Sent: Tuesday, October 13, 2009 6:31 PM
To: William Tracy (wtracy)
Cc: John Calcote; automake@...
Subject: Re: Difficulty cross-compiling

William,

I did a lot of what you are talking about when I was there - do you have
access to any of the ATC stuff?

H