Multi-architecture binaries

[Anders F Björklund]

Jascha Wetzel wrote:
> A thought that came up in the VM discussion...
> 
> Suppose someday we have language support for vector operations. We want
> to ship binaries that support but do not require extensions like SSE. We
> do not want to ship multiple binaries and wrappers that switch between
> them or installers that decide which one to use, because it's more work
> and we'd be shipping a lot of redundant code.

On a totally unrelated note we are using GDC to build Universal Binaries
for Mac OS X, that is: objects with both i386 (=i686) and ppc (=powerpc)
code. They are however twice as big as when building for just one arch.

$ file hello
hello: Mach-O universal binary with 2 architectures
hello (for architecture ppc):   Mach-O executable ppc
hello (for architecture i386):  Mach-O executable i386

The GCC driver automatically runs two compilation steps and lipos them,
so it's pretty straight-forward to use (unrelated to vector ops, though)
gdc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch ppc -arch i386 ...

It only does one variant for each architecture, so no help for a "JIT".

--anders