From ed43946572483f725796bbb257904800598e6fc5 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Thu, 20 Feb 2014 14:54:57 +1900 Subject: [PATCH] Re: [PATCH 1/1] emacs: always write emacs/.eldeps when the target is remade --- e2/6fcd18f883b0e495e22148f4aa41bb137acf2f | 239 ++++++++++++++++++++++ 1 file changed, 239 insertions(+) create mode 100644 e2/6fcd18f883b0e495e22148f4aa41bb137acf2f diff --git a/e2/6fcd18f883b0e495e22148f4aa41bb137acf2f b/e2/6fcd18f883b0e495e22148f4aa41bb137acf2f new file mode 100644 index 000000000..1cb1f76b2 --- /dev/null +++ b/e2/6fcd18f883b0e495e22148f4aa41bb137acf2f @@ -0,0 +1,239 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id 2BFCC431FBD + for ; Wed, 19 Feb 2014 11:55:12 -0800 (PST) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Spam-Flag: NO +X-Spam-Score: -0.7 +X-Spam-Level: +X-Spam-Status: No, score=-0.7 tagged_above=-999 required=5 + tests=[RCVD_IN_DNSWL_LOW=-0.7] autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id xEYHbvnwpr6n for ; 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+ Wed, 19 Feb 2014 14:55:00 -0500 +Received: from amthrax by awakening.csail.mit.edu with local (Exim 4.80) + (envelope-from ) + id 1WGDEQ-0001A9-44; Wed, 19 Feb 2014 14:54:58 -0500 +Date: Wed, 19 Feb 2014 14:54:57 -0500 +From: Austin Clements +To: Tomi Ollila +Subject: Re: [PATCH 1/1] emacs: always write emacs/.eldeps when the target is + remade +Message-ID: <20140219195457.GD13537@mit.edu> +References: <1390645309-2326-1-git-send-email-tomi.ollila@iki.fi> + <20140213071026.GX4375@mit.edu> + <20140213074944.GY4375@mit.edu> + <20140214215736.GD4375@mit.edu> +MIME-Version: 1.0 +Content-Type: text/plain; charset=us-ascii +Content-Disposition: inline +In-Reply-To: <20140214215736.GD4375@mit.edu> +User-Agent: Mutt/1.5.21 (2010-09-15) +X-Brightmail-Tracker: + H4sIAAAAAAAAA+NgFmpmleLIzCtJLcpLzFFi42IR4hRV1hXjYQ02+L/OwuL6zZnMFm9WzmN1 + YPI4/HUhi8ezVbeYA5iiuGxSUnMyy1KL9O0SuDKm7NjBWLDarOJ243bGBsYjWl2MnBwSAiYS + X//NYYawxSQu3FvPBmILCcxmkvhzXKeLkQvI3sgoMe/GFhaIxGkmiaaWQIjEEkaJ2+f+gnWz + CKhKXHj1hh3EZhPQkNi2fzkjiC0ioCLxoG09K4jNLCAt8e13MxOILSwQJjFz0WmwXl4BHYlD + 9x6yQQz9zChxfNs8RoiEoMTJmU9YIJq1JG78ewnUzAE2aPk/DpAwJ1BvZ18b2HxRoF1TTm5j + m8AoNAtJ9ywk3bMQuhcwMq9ilE3JrdLNTczMKU5N1i1OTszLSy3SNdHLzSzRS00p3cQIDmtJ + /h2M3w4qHWIU4GBU4uFluMoSLMSaWFZcmXuIUZKDSUmUdx0Ta7AQX1J+SmVGYnFGfFFpTmrx + IUYJDmYlEd5oNqAcb0piZVVqUT5MSpqDRUmct9biV5CQQHpiSWp2ampBahFMVoaDQ0mCt5Qb + qFGwKDU9tSItM6cEIc3EwQkynAdo+CSQGt7igsTc4sx0iPwpRkUpcd7XHEAJAZBERmkeXC8s + 7bxiFAd6RZh3Okg7DzBlwXW/AhrMBDTYay8jyOCSRISUVAOj3bfr6rtiiqcmcz2aNc3HQ9N6 + XXfUKXbJp0mPGEJ3Pf95WEvm6bzAf4/iLy+dbf3V6qX6BTth85rsN6tLoueeniUaWNhzLYtF + bYHcJkttsXR/De0n8y1P5k9ZfXaWZJvPaWPVA9rKB3zU+xmnCps/yE96d/CHw6zpgReU69t4 + /oWWh5xodVRRYinOSDTUYi4qTgQAM4ZivhYDAAA= +Cc: notmuch@notmuchmail.org +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Wed, 19 Feb 2014 19:55:12 -0000 + +Quoth myself on Feb 14 at 4:58 pm: +> Quoth Tomi Ollila on Feb 14 at 9:24 pm: +> > On Thu, Feb 13 2014, Austin Clements wrote: +> > +> > > Quoth Tomi Ollila on Feb 13 at 9:26 am: +> > >> On Thu, Feb 13 2014, Austin Clements wrote: +> > >> +> > >> > Quoth Tomi Ollila on Jan 25 at 12:21 pm: +> > >> >> So that the target is newer than its prerequisites. +> > >> >> --- +> > >> >> emacs/Makefile.local | 3 +-- +> > >> >> 1 file changed, 1 insertion(+), 2 deletions(-) +> > >> >> +> > >> >> diff --git a/emacs/Makefile.local b/emacs/Makefile.local +> > >> >> index 42bfbd9..d5d402e 100644 +> > >> >> --- a/emacs/Makefile.local +> > >> >> +++ b/emacs/Makefile.local +> > >> >> @@ -32,8 +32,7 @@ emacs_bytecode = $(emacs_sources:.el=.elc) +> > >> >> ifeq ($(HAVE_EMACS),1) +> > >> >> $(dir)/.eldeps: $(dir)/Makefile.local $(dir)/make-deps.el $(emacs_sources) +> > >> >> $(call quiet,EMACS) --directory emacs -batch -l make-deps.el \ +> > >> >> - -f batch-make-deps $(emacs_sources) > $@.tmp && \ +> > >> >> - (cmp -s $@.tmp $@ || mv $@.tmp $@) +> > >> >> + -f batch-make-deps $(emacs_sources) > $@.tmp && mv $@.tmp $@ +> > >> >> -include $(dir)/.eldeps +> > >> >> endif +> > >> >> CLEAN+=$(dir)/.eldeps $(dir)/.eldeps.tmp +> > >> > +> > >> > Is this just so the rule doesn't get run again on the next make +> > >> > invocation (unless, of course, a dependent changed)? +> > >> +> > >> Basically yes. I did multiple builds in rapid succession when developing +> > >> something and this thing confused me quite a lot in the beginning... +> > >> +> > >> > Interestingly, if any of the dependents have changed, but in ways that +> > >> > don't affect .eldeps, this change will make the build more expensive +> > >> > because it will trigger a make restart after .eldeps is updated. +> > >> +> > >> I wondered what was the reason for the recipe you've chosen here, has +> > >> it something to do with inodes or something ;) (and were going to ask +> > >> an alternative to touch (or even : > $@) the target... +> > >> +> > >> ... but now I understand. E.g. change in notmuch-lib.el will cause *all* +> > >> .el files to be re-bytecompiled after this change. +> > > +> > > This is unrelated to the cmp in the recipe. A change in +> > > notmuch-lib.el *must* cause almost all .el files to be recompiled +> > > because they almost all require it and may use macros from it. If you +> > > touch, e.g., notmuch-hello.el, you'll see that very little is rebuilt +> > > (with or without this patch). +> > > +> > >> An alternative to this patch would be adding a message to the rule +> > >> which informs user to touch .eldeps to avoid re-doing .eldeps if +> > >> that irritates one :D +> > >> +> > >> something like: +> > >> +> > >> (cmp -s $@.tmp $@ && \ +> > >> echo "touch $@ to avoid redoing this target" || mv $@.tmp $@) +> > > +> > > I think this patch is good as it is; I was just pointing out that the +> > > change also has a performance drawback in some situations. (Knowing +> > > make, there's probably *some* way to get the best of both worlds and +> > > it's probably really ugly.) +> > +> > Ah, now I understand, because emacs/Makefile.local includes emacs/.eldeps +> > when it notices mtime of emacs/.eldeps changes it restarts itself... +> > +> > ... to compare with current behaviour: +> > +> > $ make +> > ... +> > $ touch emacs/notmuch.el +> > $ make +> > ... +> > $ make +> > Use "make V=1" to see the verbose compile lines. +> > EMACS emacs/.eldeps +> > make: Nothing to be done for `all'. +> > $ make +> > Use "make V=1" to see the verbose compile lines. +> > EMACS emacs/.eldeps +> > make: Nothing to be done for `all'. +> > $ make +> > Use "make V=1" to see the verbose compile lines. +> > EMACS emacs/.eldeps +> > make: Nothing to be done for `all'. +> > +> > It will rerun emacs -L emacs -batch -l make-deps.el -f batch-make-deps ... +> > over and over again... +> > +> > I thought I figured out a solution involving .eldeps.stamp file but +> > that turned out to be no-go... (circular dependency netween .eldeps.stamp +> > and Makefile.local). +> > +> > So, with this if one edits emacs/* files and keeps building byte-compiled +> > versions often, make will both run EMACS emacs/.eldeps and restarting +> > -- and when moving to edit other files both of the above stops. Without +> > this change after editing emacs/* files EMACS emacs/.eldeps will be +> > executed until it is touched or make clean executed (I wonder how make +> > handles rebuilding emacs/.eldeps while doing make clean ;) +> > +> > +> > Tomi +> +> Here's a way that works, but it's more complicated than your patch and +> doesn't seem to perform any better: +> +> diff --git a/emacs/Makefile.local b/emacs/Makefile.local +> index 42bfbd9..8a1f1c2 100644 +> --- a/emacs/Makefile.local +> +++ b/emacs/Makefile.local +> @@ -29,14 +29,28 @@ emacs_bytecode = $(emacs_sources:.el=.elc) +> # the byte compiler may load an old .elc file when processing a +> # "require" or we may fail to rebuild a .elc that depended on a macro +> # from an updated file. +> +# +> +# We do this in two rules. .eldeps is the "real" dependencies file +> +# and will be rebuilt if and only if a .el source file changes. We +> +# could include this directly, but then whenever a .el file changed +> +# (and .eldeps's mtime changed), make would restart immediately after +> +# the include below. To avoid this, we create a second file, +> +# .eldeps.x, that we only update when its *contents* differ from +> +# .eldeps. .eldeps will often have an mtime older than .eldeps.x (any +> +# .el file change that does not change dependencies will cause this), +> +# so the .eldeps.x rule will often run, but it executes quickly and +> +# quietly and will not trigger a make restart unless the dependencies +> +# actually change. + +Here's a version of this comment that gets to the point directly: + +# We could include .eldeps directly, but that would cause a make +# restart whenever any .el file was modified, even if dependencies +# didn't change, because the mtime of .eldeps will change. Instead, +# we include a second file, .eldeps.x, which we ensure always has the +# same content as .eldeps, but its mtime only changes when dependency +# information changes, in which case a make restart is necessary +# anyway. + +> ifeq ($(HAVE_EMACS),1) +> $(dir)/.eldeps: $(dir)/Makefile.local $(dir)/make-deps.el $(emacs_sources) +> $(call quiet,EMACS) --directory emacs -batch -l make-deps.el \ +> -f batch-make-deps $(emacs_sources) > $@.tmp && \ +> - (cmp -s $@.tmp $@ || mv $@.tmp $@) +> --include $(dir)/.eldeps +> + mv $@.tmp $@ +> +$(dir)/.eldeps.x: $(dir)/.eldeps +> + @cmp -s $^ $@ || cp $^ $@ +> +-include $(dir)/.eldeps.x +> endif +> -CLEAN+=$(dir)/.eldeps $(dir)/.eldeps.tmp +> +CLEAN+=$(dir)/.eldeps $(dir)/.eldeps.tmp $(dir)/.eldeps.x +> +> ifeq ($(HAVE_EMACS),1) +> %.elc: %.el $(global_deps) -- 2.26.2