From: Carl Worth <cworth@cworth.org>
Date: Tue, 10 Nov 2009 16:04:54 +0000 (-0800)
Subject: Makefile: Fix dependency generation to make .d files themselves dependent.
X-Git-Tag: 0.1~548
X-Git-Url: https://git.notmuchmail.org/git?p=notmuch;a=commitdiff_plain;h=97c7cffdc6e0047bb49a899b013516bc3022e580;hp=c5dccd851a8b79d8cedbfc8f2d2b8f9be2b7fa5a

Makefile: Fix dependency generation to make .d files themselves dependent.

I saw this recommendation in the implementation notes for "Recursive
Make Considered Harmful" and then the further recommendation for
implementing the idea in the GNU make manual.

The idea is that if any of the files change then we need to regenerate
the dependency file before we regenerate any targets.

The approach from the GNU make manual is simpler in that it just uses
a sed script to fix up the output of an extra invocation of the
compiler, (as opposed to the approach in the implementation notes from
the paper's author which use a wrapper script for the compiler that's
always invoked rather than the compiler itself).
---

diff --git a/Makefile b/Makefile
index 91ab9c02..7743ef52 100644
--- a/Makefile
+++ b/Makefile
@@ -19,14 +19,21 @@ include lib/Makefile.local
 %.o: %.c
 	$(CC) -c $(CFLAGS) $(NOTMUCH_CFLAGS) $< -o $@
 
-.depends: $(SRCS)
-	$(CXX) -M $(CPPFLAGS) $(NOTMUCH_DEPENDS_FLAGS) \
-	$(NOTMUCH_CXX_DEPENDS_FLAGS) $^ > $@
--include .depends
-
-CLEAN := $(CLEAN) .depends
+.deps/%.d: %.c
+	@set -e; rm -f $@; mkdir -p $$(dirname $@) ; \
+	$(CC) -M $(CPPFLAGS) $(NOTMUCH_DEPENDS_FLAGS) $< > $@.$$$$; \
+	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
+	rm -f $@.$$$$
+
+.deps/%.d: %.cc
+	@set -e; rm -f $@; mkdir -p $$(dirname $@) ; \
+	$(CXX) -M $(CPPFLAGS) $(NOTMUCH_CXX_DEPENDS_FLAGS) $< > $@.$$$$; \
+	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
+	rm -f $@.$$$$
+
+DEPS := $(SRCS:%.c=.deps/%.d)
+DEPS := $(DEPS:%.cc=.deps/%.d)
+-include $(DEPS)
 
 clean:
-	rm -f $(CLEAN)
-
-
+	rm -f $(CLEAN); rm -rf .deps
diff --git a/lib/Makefile.local b/lib/Makefile.local
index b5182bc4..43882a3d 100644
--- a/lib/Makefile.local
+++ b/lib/Makefile.local
@@ -1,19 +1,22 @@
 dir=lib
 
-lib_notmuch_modules =		\
-	$(dir)/database.o	\
-	$(dir)/index.o		\
-	$(dir)/$(dir)sha1.o	\
-	$(dir)/message.o	\
-	$(dir)/message-file.o	\
-	$(dir)/query.o		\
-	$(dir)/sha1.o		\
-	$(dir)/tags.o		\
-	$(dir)/thread.o		\
-	$(dir)/xutil.o
+libnotmuch_c_srcs =		\
+	$(dir)/libsha1.c	\
+	$(dir)/message-file.c	\
+	$(dir)/sha1.c		\
+	$(dir)/tags.c		\
+	$(dir)/xutil.c
 
-$(dir)/notmuch.a: $(lib_notmuch_modules)
+libnotmuch_cxx_srcs =		\
+	$(dir)/database.cc	\
+	$(dir)/index.cc		\
+	$(dir)/message.cc	\
+	$(dir)/query.cc		\
+	$(dir)/thread.cc
+
+libnotmuch_modules = $(libnotmuch_c_srcs:.c=.o) $(libnotmuch_cxx_srcs:.cc=.o)
+$(dir)/notmuch.a: $(libnotmuch_modules)
 	$(AR) rcs $@ $^
 
-SRCS  := $(SRCS) lib/*.c lib/*.cc
-CLEAN := $(CLEAN) $(dir)/*.o $(dir)/notmuch.a
+SRCS  := $(SRCS) $(libnotmuch_c_srcs) $(libnotmuch_cxx_srcs)
+CLEAN := $(CLEAN) $(libnotmuch_modules) $(dir)/notmuch.a