Re: [Boost-build] Cross compiling to 64 bit on 32 bit host

Subject: Re: [Boost-build] Cross compiling to 64 bit on 32 bit host
From: Vladimir Prus (ghost_at_[hidden])
Date: 2011-03-19 06:12:59

On Saturday, March 19, 2011 12:43:24 Bo Jensen wrote:
> On Fri, Mar 18, 2011 at 5:26 PM, Vladimir Prus <ghost_at_[hidden]> wrote:
> > On Friday, March 18, 2011 18:38:40 Bo Jensen wrote:
> >> On Fri, Mar 18, 2011 at 2:54 PM, Vladimir Prus <ghost_at_[hidden]> wrote:
> >> > On Friday, March 18, 2011 17:35:32 Bo Jensen wrote:
> >> >> I am trying to build my 64 bit libraries on a 32 bit host and almost
> >> >> got it right. I can build correctly with gcc when adding -m64 on the
> >> >> commandline, so the libraries are all there. But when I build using
> >> >> boost build, the I get the following error :
> >> >> 
> >> >> /usr/bin/ld:
> >> >> /home/bj/sulum/external/boost/bin.v2/libs/thread/build/gcc-4.4.1/rele
> >> >> ase /a
> >> >> ddress-model-64/link-static/threading-multi/libboost_thread.a(thread.
> >> >> o)
> >> >> 
> >> >> : relocation R_X86_64_32 against `tls_destructor' can not be used
> >> >> : when
> >> >> 
> >> >> making a shared object; recompile with -fPIC
> >> >> /home/bj/sulum/external/boost/bin.v2/libs/thread/build/gcc-4.4.1/rele
> >> >> ase /ad dress-model-64/link-static/threading-multi/libboost_thread.a:
> >> >> could not read symbols: Bad value
> >> >> collect2: ld returned 1 exit status
> >> >> 
> >> >> I don't think it has any thing to do with thread library, I am
> >> >> missing something.
> >> >> 
> >> >> But all files are being compiled with -fPIC, so I am a bit stuck, any
> >> >> pointers appreciated ?
> >> > 
> >> > That's a well known issue -- dynamic executable for 64 bit x86 cannot
> >> > use non-fPIC code at all, and therefore using static libraries in
> >> > such build results in the error you see.
> >> 
> >> Vladimir, thanks for the reply, much appreciated.
> >> 
> >> Hmm maybe a dumb question, but how do I then build my library
> >> including boost libs into one shared library ? Right now I build a
> >> bunch of static libs and included them into a shared library, from
> >> what you say this is not possible on 64 bit.
> > 
> > Bo,
> > 
> > you have two options, basically:
> > 
> > - You shared libraries, which is really the best approach
> > - Clean your entire Boost tree (e.g. remove bin.v2), and then do:
> > 
> >        bjam link=static cxxflags=-fPIC
> > 
> > HTH,
> 
> Thanks.
> 
> Ok, I got it working, though I was confused by why some libraries
> linked fine without -fPIC flag, turned out they were redundant and not
> used any more or linked into a executable.
> 
> I still have one thing which annoys me, I think the following should work :
> 
> <library>../../../external/boost/libs/thread/build//<link>static
> <cxxflags>-fPIC

You mean, with a slash between <link>static and <cxxflags>-fPIC?

> but it does not add the flags when compiling in thread library. Is
> this intended ? 

Probably note. However, could you please try the attached. Building with -n,
I see both -DFOO and -bar options passed to the compiler.

> For some reason it takes forever to add flags on the
> commandline, 

You mean, it reduces performance? Are you using current Boost.Build? There
was a patch that fixed nasty behaviour in that department.

- Volodya

-- 
Vladimir Prus
http://vladimir_prus.blogspot.com
Boost.Build: http://boost.org/boost-build2