Re: [Chicken-hackers] Questions about cross-compiling Chicken

[Felix]

> The "Cross development" chapter in the manual
> (http://wiki.call-cc.org/man/4/Cross%20development) suggests the
> following command line to build Chicken for the target machine:
> 
>   make ARCH= \
>        PREFIX=/usr \
>        PLATFORM=linux \
>        HOSTSYSTEM=arm-none-linux-gnueabi \
>        DESTDIR=$HOME/target \
>        TARGET_FEATURES="-no-feature x86 -feature arm" \
>        install
> 
> Some questions:
> 
> 1. Shouldn't ARCH be set with the target platform instead of set empty?  

Possibly, yes. It is important not to assume the host system's ARCH,
so it must be overridden. 

> 
> If it is empty, I suppose apply-hack won't be applied, even if it is
> supported on the target platform.  Is it right?  If so, wouldn't it be
> better to provide a value for ARCH?

Yes, I think so.

> 
> 
> 2. On TARGET_FEATURES="-no-feature x86 -feature arm"
> 
> If I understand the hardware-related feature correctly, it is set
> according to `machine-type', which is determined (in chicken.h --
> C_MACHINE_TYPE) based on constants defined by the toolchain header
> files.  Since we provide HOSTSYSTEM, and C_COMPILER gets its value based
> on that (i.e., the toolchain has been selected), is it necessary to
> explicitly set TARGET_FEATURES?

The host-system will have features defined for the host architecture.
If you have compile-time expressions like

  (cond-expand (x86 ...) ...)

they will be selected for the system that you are cross-building on,
not for the target. Well, I think so. It is all very confusing. :-)


cheers,
felix