Date: Tue, 16 Nov 1999 17:44:39 +0100 From: Marcel Moolenaar <marcel@scc.nl> To: Warner Losh <imp@village.org> Cc: cvs-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src Makefile.inc1 src/usr.bin/make Makefile Message-ID: <383189F7.67E89E8B@scc.nl> References: <38310A94.B1939A83@scc.nl> <199911151707.JAA03820@freefall.freebsd.org> <199911160533.WAA02391@harmony.village.org> <199911161544.IAA08642@harmony.village.org>
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Warner Losh wrote:
>
> In message <38310A94.B1939A83@scc.nl> Marcel Moolenaar writes:
> : If make is compiled against the right set of headers, you are never
> : going to need this. The Makefiles are full of those `cross-compilation'
> : hacks that are basicly only needed because cross-building is broken by
> : design. The only way to fix cross-building is to get to the bones of
> : things and CROSS_MAKE_FLAGS is currently in the way.
>
> But without them, make won't define MACHINE and MACHINE_ARCH
> correctly, which is critical to have any sort of cross building work.
When MACHINE_ARCH is used to denote the target machine instead of the
host machine (which it represents by definition), then you only have to
set MACHINE_ARCH in the environment (although the commandline works as
well). Make uses the environment variables if they are present. Make is
not a cross-tool.
> I was unable to get cross compiling working at all by defining MACHINE
> and MACHINE_ARCH on the command line, but I think that is due to make
> trying to second guess things (maybe this code has been slain inside
> of make). That's why it was needed. What are you replacing it with?
> What's your cross building direction?
My first approach was to leave MACHINE{_ARCH} alone and use
TARGET{_ARCH} for that. The problem is that you need to modify a lot of
makefiles. I abandoned it. I now want the main makefile (ie
/usr/src/Makefile) to add MACHINE and MACHINE_ARCH to the environment
used by the sub-makes (although it's not actually needed):
Assume the following makefile:
default: second
make second
second:
@echo machine=${MACHINE}
@echo machine_arch=${MACHINE_ARCH}
% make
machine=i386
machine_arch=i386
make second
machine=i386
machine_arch=i386
% make MACHINE_ARCH=alpha
machine=i386
machine_arch=alpha
make second
machine=i386
machine_arch=alpha
I want to use TARGET_ARCH for building the cross-compiler:
[Assume we're running on an i386]
MACHINE_ARCH = i386, TARGET_ARCH = i386
Regular build and no cross-compiler.
MACHINE_ARCH = i386, TARGET_ARCH = mips
Make a cross-compiler to cross-build for MIPS (used for
building cross-tools on i386).
MACHINE_ARCH = mips, TARGET_ARCH = mips
Cross-build for MIPS and don't build a cross-compiler
(used to make the native MIPS compiler).
MACHINE_ARCH = mips, TARGET_ARCH = alpha
Cross-build for MIPS and make a cross-compiler for Alpha
(to run on MIPS) (It's free :-)
Currently MACHINE_ARCH is tested against `sysctl -n hw.machine_arch` and
if they differ then we're building a cross-compiler. This obviously
doesn't work if we are making the native MIPS compiler in a
cross-build...
--
Marcel Moolenaar mailto:marcel@scc.nl
SCC Internetworking & Databases http://www.scc.nl/
The FreeBSD project mailto:marcel@FreeBSD.org
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