Date: Mon, 14 Jun 2010 09:44:40 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: brde@optusnet.com.au Cc: des@des.no, arch@FreeBSD.org Subject: Re: Change to config(8) for OFED Message-ID: <20100614.094440.321689434066253255.imp@bsdimp.com> In-Reply-To: <20100614201541.B37598@delplex.bde.org> References: <20100612.111805.94843338670897167.imp@bsdimp.com> <86zkz05bra.fsf@ds4.des.no> <20100614201541.B37598@delplex.bde.org>
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In message: <20100614201541.B37598@delplex.bde.org>
Bruce Evans <brde@optusnet.com.au> writes:
: On Sat, 12 Jun 2010, [utf-8] Dag-Erling Smørgrav wrote:
:
: > "M. Warner Losh" <imp@bsdimp.com> writes:
: >> but NORMAL_C is
: >>
: >> NORMAL_C= ${CC} -c ${CFLAGS} ${WERROR} ${PROF} ${.IMPSRC}
: >>
: >> and .IMPSRC is null. That seems like a bug to me, but I'm not sure if
: >> the bug is that .IMPSRC is computed wrong, or if it really should be
: >> ${.ALLSRC}
: >
: > .IMPSRC is the *implicit* source and is only valid in *implicit*
: > rules.
:
: However, NORMAL_C and related macros have always depended on it being
: defined to something reasonable so that they can abuse it in explicit
: rules.
:
: > Consider the following:
: >
: > .SUFFIXES: .foo .bar
: > .foo.bar: foo2bar.sh
: > /bin/sh foo2bar.sh ${.IMPSRC} ${.TARGET}
: >
: > When building hello.bar from hello.foo, .IMPSRC is "hello.foo" but
: > .ALLSRC
: > is "hello.foo foo2bar.sh".
: >
: > GNU make has a way of defining more complex implicit rules (pattern
: > rules). If we had something similar, we could do:
: >
: > foo_%.o: %.c
: > ${NORMAL_C}
:
: BSD make can handle simple cases like this using pattern filters and
: substitution. E.g.:
:
: %%%
: ABNORMAL_C= ${CC} -c ${CFLAGS} ${WERROR} ${PROF}
: ${.ALLSRC:M*.c:S/^foo_//}
: # Untested more careful patterns: ${.ALLSRC:M^foo*.c$:S/^foo_//}
:
: bar.o: foo_bar.c stuff.nonc
: ${ABNORMAL_C}
: %%%
That would work. Not sure I like it, but it would work.
: This has no alternative of using .IMPSRC instead of .ALLSRC since its
: .IMPSRC is empty with the above dependencies. The rule for getting a
: nonempty .IMPSRC in an explicit dependency with BSD makef seems to be:
:
: some of the sources must match the target according to a suffix
: rule; then the first matching one (according to the order of the
: sources in the dependency list for the target) becomes .IMPSRC,
: so .IMPSRC always contains either 0 or 1 name.
:
: I've don't remember having seen the exact rule documented.
I've never seen this rule documented either. It is only a repeated
observation that I've seen over the years. When I tried to chase it
into the source, I couldn't find the place that did this...
Warner
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