Date: Thu, 5 Feb 2015 20:18:28 -0700 From: Warner Losh <imp@bsdimp.com> To: Julian Elischer <julian@freebsd.org> Cc: "freebsd-arch@freebsd.org" <arch@FreeBSD.org> Subject: Re: Better way to do conditional inclusion in make Message-ID: <07D8BEB5-8142-431A-B823-4900D664CEE2@bsdimp.com> In-Reply-To: <54D40DC4.9070907@freebsd.org> References: <39C20BA1-E6B1-4DAE-95BB-8011A0A64D54@bsdimp.com> <54D40DC4.9070907@freebsd.org>
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> On Feb 5, 2015, at 5:41 PM, Julian Elischer <julian@freebsd.org> wrote: > > On 2/6/15 1:56 AM, Warner Losh wrote: >> Greetings, >> >> I’ve started a pass through the tree to cleanup how we do conditional inclusion in our build system. >> >> https://reviews.freebsd.org/D1781 >> >> It moves away from >> >> .if ${MK_foo} != “no” >> FILES+= files >> .endif >> >> and >> >> SUBDIRS= … ${_foo} … >> ... >> .if ${MK_foo} != “no” >> _foo+= foo >> .endif >> >> and instead more directly assigns things. We know that MK_foo is always going to be yes or no >> for build options. We can leverage that fact, and the fact that bmake is so much better at variable >> expansion than fmake was (especially in the early days) to instead move to something like: >> >> FILES=list of unconditional files here ${FILES.yes} >> FILES.${MK_foo}+=foo bar biz >> FILES.${MK_baz}+=baz bing boo >> >> which eliminates a whole lot of needless .if / .endif lines, lots of extra blank lines, etc. >> >> Comments? > > how does it cope with the case where a single file is dependent on either of two options. > (we have this in our tree.. not sure if it occurs in the FreeBSD tree.) > file could occur in both lists or twice in one list.. We have this in our tree a fair amount. power, for example, is enabled with either MK_ACPI or MK_APM. When it is either/or, just list it for both. FILES.${MK_APCI}+= acpiconf powerd FILES.${MK_APM}+= powerd The FILES:=${FILES:O:u} at the end sorts everything and removes the duplicates. Warner
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