Re: TARGET_ARCH

[John Hein]

Oleksandr Gavenko wrote at 15:27 +0300 on May 28, 2010:
 > On 2010.05.27 18:09, address@hidden wrote:
 > > What is TARGET_ARCH typically expected to be set to for cross building 
 > > with the implicit gmake rules?
 > >
 > > The C implicit rule is:
 > > COMPILE.c = $(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c
 > >
 > > But most hits I see talk about defining TARGET_ARCH to be "arm" or 
 > > similar.  Of course, doing that makes gcc say "gcc: arm: N\
o such file or directory".
 > >
 > > The info pages have nothing to say.
 > >
 > > The only reference I saw in the mailing list archives was from 2005, and 
 > > it advised just not using implicit rules.
 > >
 >   $ info make | grep TARGET_ARCH  || echo nothing found
 > 
 > print nothing found. This is not GNU Make issue.

I am aware there is no documentation for TARGET_ARCH.  That doesn't
change the fact that the built-in implicit rules reference
it.  For those reasons (no docs for TARGET_ARCH, but built-in
rules using it), I would call it a gmake issue.

More than likely, TARGET_ARCH was intended to be something like
-march=armv5.  I was seeking confirmation of that on the list.  This
varies from lots of examples in the wild that define TARGET_ARCH to
'arm' and the like (that is, not yet converted to compiler switches).
Many (most?) of these examples are not gmake makefiles, of course.

The main issue is that there aren't any gmake docs for it.  This is
just a documentation bug, and perhaps that's why there are few
examples of TARGET_ARCH gmake usage in the wild.