Date: Tue, 10 Sep 1996 05:02:22 +1000 From: Bruce Evans <bde@zeta.org.au> To: freebsd-current@freebsd.org, swallace@ece.uci.edu Subject: Re: Object directory changes to make Message-ID: <199609091902.FAA24911@godzilla.zeta.org.au>
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>I like the new functionality for building the source trees, but
>I do not like removing the old functionality either. Therefore,
>I made changes to make so that it will accompish both.
So did I :-).
>First make will search for MAKEOBJDIR.machine, then MAKEOBJDIR,
>as previously done. Then if both failed it will search for
>MAKEOBJDIRPREFIX/`cwd`/machine and then MAKEOBJDIRPREFIX/`cwd`.
>If all fails the cwd is used.
I use an environment variable MAKEOBJTREE instead of the hard coded
prefix MAKEOBJDIRPREFIX. Experience showed:
1) The environment variable is too inconvenient (as expected). It
will have to be hard-coded for a transitional period until it can
be read from an include file (`make' now doesn't read include files
until after it decides the object dir. This behaviour is fundamental
because ifdefs etc. to control the reading of include files may depend
on the object dir).
2) There should be no slash between MAKEOBJDIRPREFIX and `cwd`. `cwd`
begins with a slash (except possibly when it is actually $PWD), and
the extra slash is unnecessary if MAKEOBJDIRPRFIX is nonempty and a
bug otherwise.
3) .TARGETOBJDIR is bogus and unnecessary. bsd.obj.mk can easily
concatenate ${MAKEOBJDIRPREFIX} and ${.CURDIR} itself provided it
knows ${MAKEOBJDIR}. It needs to do this to get an unambiguous
path. Chdir checks in `make' don't work because the name of the
path must not depend on the existence of the path.
This seems to be quite broken in your version. .TARGETOBJDIR is set
${path}.${MACHINE}, where ${path} is ${MAKEOBJDIR} if that is set in
the environment, else "obj". This seems to break both the new and
the old tree names.
4) MAKEOBJDIRPREFIX is a better name than MAKEOBJTREE.
5) .${MACHINE} causes similar problems to ${MAKEOBJTREE}/. It should
be a general suffix, named ${MAKEOBJDIRSUFFIX} and any necessary
punctuation (usually "."; perhaps "/") should be part of the suffix.
It should not be decided inside `make'.
6) `make's builtin search path should go away. The effect of its
builtin "obj" path can easily be obtained using the new
MAKEOBJDIRPREFIX. It probably isn't necessary for the prefix to
actually be a search path, and the ambiguity for a path usually gets
in the way. Overriding the prefix is probably good enough doing
local changes. MAKEOBJDIR didn't work before, so it won't be missed.
Bruce
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