From a170b51898e7e63b3e8c4d4d86f8cea121cf50d1 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Mon, 9 Apr 2012 00:01:50 +2000 Subject: [PATCH] [PATCH] Record dependencies during build instead of before --- 10/183b357e5826d2aec9f62141a1a06fa684a4f5 | 136 ++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 10/183b357e5826d2aec9f62141a1a06fa684a4f5 diff --git a/10/183b357e5826d2aec9f62141a1a06fa684a4f5 b/10/183b357e5826d2aec9f62141a1a06fa684a4f5 new file mode 100644 index 000000000..ed7fad13b --- /dev/null +++ b/10/183b357e5826d2aec9f62141a1a06fa684a4f5 @@ -0,0 +1,136 @@ +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 19C69431FAF + for ; Sat, 7 Apr 2012 21:01:59 -0700 (PDT) +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 XZmwpt6JB6VA for ; + Sat, 7 Apr 2012 21:01:58 -0700 (PDT) +Received: from dmz-mailsec-scanner-2.mit.edu (DMZ-MAILSEC-SCANNER-2.MIT.EDU + [18.9.25.13]) + by olra.theworths.org (Postfix) with ESMTP id 6B0BE431FAE + for ; Sat, 7 Apr 2012 21:01:58 -0700 (PDT) +X-AuditID: 1209190d-b7fbf6d0000008ba-06-4f810db57211 +Received: from mailhub-auth-2.mit.edu ( [18.7.62.36]) + by dmz-mailsec-scanner-2.mit.edu (Symantec Messaging Gateway) with SMTP + id C3.21.02234.5BD018F4; Sun, 8 Apr 2012 00:01:57 -0400 (EDT) +Received: from outgoing.mit.edu (OUTGOING-AUTH.MIT.EDU [18.7.22.103]) + by mailhub-auth-2.mit.edu (8.13.8/8.9.2) with ESMTP id q3841ueP019597; + Sun, 8 Apr 2012 00:01:56 -0400 +Received: from drake.mit.edu + (209-6-116-242.c3-0.arl-ubr1.sbo-arl.ma.cable.rcn.com + [209.6.116.242]) (authenticated bits=0) + (User authenticated as amdragon@ATHENA.MIT.EDU) + by outgoing.mit.edu (8.13.6/8.12.4) with ESMTP id q3841run018608 + (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NOT); + Sun, 8 Apr 2012 00:01:56 -0400 (EDT) +Received: from amthrax by drake.mit.edu with local (Exim 4.77) + (envelope-from ) + id 1SGjK4-0006PU-PN; Sun, 08 Apr 2012 00:01:52 -0400 +From: Austin Clements +To: notmuch@notmuchmail.org +Subject: [PATCH] Record dependencies during build instead of before +Date: Sun, 8 Apr 2012 00:01:50 -0400 +Message-Id: <1333857710-24511-1-git-send-email-amdragon@mit.edu> +X-Mailer: git-send-email 1.7.9.1 +X-Brightmail-Tracker: + H4sIAAAAAAAAA+NgFprJIsWRmVeSWpSXmKPExsUixG6noruVt9HfYO5PHovrN2cyOzB6PFt1 + izmAMYrLJiU1J7MstUjfLoErY/GHT4wFu8UqXixsYm5gnCzUxcjBISFgIjFlXlAXIyeQKSZx + 4d56ti5GLg4hgX2MEuuvL2OEcNYzSnRNPsIM4dxjkljRfhKqbD6jRP+Pmawg/WwCGhLb9i9n + BLFFBKQldt6dzQqygllATeJPlwqIKSzgLDHjNg9IBYuAqsT/w1fYQWxeAQeJLT3PWCGuUJB4 + tu440wRG3gWMDKsYZVNyq3RzEzNzilOTdYuTE/PyUot0jfRyM0v0UlNKNzGCQoBTkncH47uD + SocYBTgYlXh4H+5o8BdiTSwrrsw9xCjJwaQkymvE3egvxJeUn1KZkVicEV9UmpNafIhRgoNZ + SYT3/mGgct6UxMqq1KJ8mJQ0B4uSOK+q1js/IYH0xJLU7NTUgtQimKwMB4eSBK8UMNSFBItS + 01Mr0jJzShDSTBycIMN5gIbzg9TwFhck5hZnpkPkTzEqSonzvucBSgiAJDJK8+B6YTH6ilEc + 6BVh3jcgVTzA+IbrfgU0mAlocM2repDBJYkIKakGRglplo06D9Sfxfd7CSeV7bZrKlKZc9vg + +Z6tSS65hwt90tffvljwrfZL42kWeT8DTc8Qvs3vDXe6d7pbJPmwM67ZrbZCdNO/fRZn1399 + /iDh+OYfxyNjFepWyq1f8z544+G5KmH5t41Ei9hvHha+rXlDR/ob4waVBXwt67yb91Rz5fxX + 3xOjqsRSnJFoqMVcVJwIAHwCWW6sAgAA +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: Sun, 08 Apr 2012 04:01:59 -0000 + +Previously, the makefile created dependency files in a separate, first +pass. In particular, include-ing the dependency files would cause +make to attempt to rebuild those files using the dependency-generation +rules in the makefile. Unfortunately, this approach required obtuse +rules and silently delayed the start of the build process (by quite a +bit on a clean tree without any dependency files). Worse, this +required the dependency files to themselves depend on all of the +headers the source file depended on, which meant that, if a header +file was removed, the depedency file could not be updated because of a +missing dependency (!), which would cause make to silently fail. + +This patch eliminates the dependency generation rules and instead +generates dependency files as a side-effect of the regular build rule. +On the first build, we don't need to know the dependencies beforehand; +the object file doesn't exist, so it will be built anyway. On +subsequent builds, if a header file is updated, the dependency rules +generated by the previous build will force a rebuild. If a source +file is updated, the dependency rules may be stale, but it doesn't +matter because the updated source file will force a rebuild. + +In the final case above, the stale dependency rules may refer to a +header file that no longer exists but is also no longer needed. In +order to prevent this from breaking the build, we also pass gcc the +-MP option, which generates phony targets for every depended-on header +file, so make won't complain if it can't find them during a later +build. +--- +The description is way more complicated than the patch. + + Makefile.local | 18 ++++-------------- + 1 files changed, 4 insertions(+), 14 deletions(-) + +diff --git a/Makefile.local b/Makefile.local +index 1131dea..525eda0 100644 +--- a/Makefile.local ++++ b/Makefile.local +@@ -256,23 +256,12 @@ endif + quiet ?= $($(shell echo $1 | sed -e s'/ .*//')) + + %.o: %.cc $(global_deps) ++ @mkdir -p .deps/$(@D) ++ $(call quiet,CXX $(CXXFLAGS)) -c $(FINAL_CXXFLAGS) $< -o $@ -MD -MP -MF .deps/$*.d +- $(call quiet,CXX $(CXXFLAGS)) -c $(FINAL_CXXFLAGS) $< -o $@ + + %.o: %.c $(global_deps) ++ @mkdir -p .deps/$(@D) ++ $(call quiet,CC $(CFLAGS)) -c $(FINAL_CFLAGS) $< -o $@ -MD -MP -MF .deps/$*.d +- $(call quiet,CC $(CFLAGS)) -c $(FINAL_CFLAGS) $< -o $@ +- +-.deps/%.d: %.c $(global_deps) +- @set -e; rm -f $@; mkdir -p $$(dirname $@) ; \ +- $(CC) -M $(CPPFLAGS) $(FINAL_CFLAGS) $< > $@.$$$$ 2>/dev/null ; \ +- sed 's,'$$(basename $*)'\.o[ :]*,$*.o $@ : ,g' < $@.$$$$ > $@; \ +- rm -f $@.$$$$ +- +-.deps/%.d: %.cc $(global_deps) +- @set -e; rm -f $@; mkdir -p $$(dirname $@) ; \ +- $(CXX) -M $(CPPFLAGS) $(FINAL_CXXFLAGS) $< > $@.$$$$ 2>/dev/null ; \ +- sed 's,'$$(basename $*)'\.o[ :]*,$*.o $@ : ,g' < $@.$$$$ > $@; \ +- rm -f $@.$$$$ + + .PHONY : clean + clean: +-- +1.7.9.1 + -- 2.26.2