[PATCH 21/29] [AARCH64] Add ILP32 to makefiles

[Joseph S. Myers]

On Tue, 28 Oct 2014, Mike Frysinger wrote:

> On 27 Oct 2014 00:59, Andrew Pinski wrote:
> > -abi-lp64-options := -U__AARCH64EB__
> > -abi-lp64-condition := !defined __AARCH64EB__
> > +abi-lp64-options := -U__AARCH64EB__ -D__LP64__ -U__ILP32__
> > +abi-lp64-condition := __WORDSIZE == 64 && !defined __AARCH64EB__
> >  
> > -abi-lp64_be-options := -D__AARCH64EB__
> > -abi-lp64_be-condition := defined __AARCH64EB__
> > +abi-lp64_be-options := -D__AARCH64EB__ -D__LP64__ -U__ILP32__
> > +abi-lp64_be-condition := __WORDSIZE == 64 && defined __AARCH64EB__
> > +
> > +abi-ilp32-options := -U__AARCH64EB__ -U__LP64__ -D__ILP32__
> > +abi-ilp32-condition := __WORDSIZE == 32 && !defined __AARCH64EB__
> > +
> > +abi-ilp32_be-options := -D__AARCH64EB__ -U__LP64__ -D__ILP32__
> > +abi-ilp32_be-condition := __WORDSIZE == 32 && defined __AARCH64EB__
> 
> why all this CPP magic ?  shouldn't the compiler be producing the right objects 
> in the first place with all the right defines ?

abi-$(variant)-options is used to generate bits/syscall.h, with a single 
glibc install generating a version of bits/syscall.h suitable for all 
ABIs.  This means that a compiler with options set up to generate code for 
one ABI needs to be forced to define macros that make asm/unistd.h define 
the syscall macros for another ABI.

If we moved bits/syscall.h to the same approach as gnu/stubs.h and 
gnu/lib-names.h (a glibc build only generates a full header for its own 
ABI, and a wrapper that selects such a header depending on the ABI in 
use), it should no longer be necessary to have abi-$(variant)-options 
variables at all.

-- 
Joseph S. Myers
joseph@codesourcery.com