64-bit two-step compilation on Ubuntu?

[Jonathan M Davis]

> == Quote from Jonathan M Davis (jmdavisProg at gmx.com)'s article
> 
> > > I'm trying to get a D2 project to build on Ubuntu through Code::Blocks.
> > > Unfortunately, Code::Blocks doesn't allow the simple one-step
> > > compilation that is default with dmd, so it does compiling and linking
> > > in two separate steps. Unfortunately, this is causing some linker
> > > errors, the main one being:
> > > 
> > > /usr/bin/ld: i386 architecture of input file `obj/Debug/main.o' is
> > > incompatible with i386:x86-64 output
> > > 
> > > I've tried passing -melf_x86_64 to the linker, and that doesn't change
> > > anything. I'm also trying to pass -m64 to the compilation step, and it
> > > doesn't work. Help?
> > 
> > First thing I'd try would be to use dmd as the linker.
> > dmd compiles in 32-bit by default. Assuming that you're using dmd 2.052,
> > then you can use -m64 to tell it to compile for 64-bit, at which point
> > linking with gcc should work. Otherwise, you'd need to pass -m32 to gcc
> > when linking (unless you're using ld directly (at which point, I don't
> > know what you do), and I'm not aware of anyone doing that - dmd
> > doesn't). Regardless, if you're linking separately and not using dmd for
> > the linking step, then you need to look at dmd.conf and make sure that
> > you include the linker flags that it does, or your code may not work.
> > In any case, my best suggestion if you can't compile and link in one step
> > would be to just use dmd for both.
> > - Jonathan M Davis
> 
> How do I use dmd as the linker separately from using it as the compiler?
> 
> As you can see in my original post, I'm passing -m64 to DMD, but it doesn't
> seem to be picking it up..

If you pass -c to dmd, it won't link, but will just produce .o files. 
Otherwise, it'll link the .o files and produce a binary. If you're doing 2 
step compilation, then you must be passing -c to dmd for the first step. So, 
for the second step, just give it the .o files instead of the .d files and 
don't pass it -c.

As for -m64, if you have a version of dmd prior to 2.052, then it only does 
32-bit compilation. If you have 2.052, then it should accept -m64 and produce 
64-bit .o files, and produce a 64-bit binary when when not using -c. If that 
doesn't work, then it needs to be reported in bugzilla.

- Jonathan M Davis