Re: [PATCH/RFC 2/2] Makefile: automatically compute header dependencies

[Jonathan Nieder <jrnieder@gmail.com>]

Sverre Rabbelier wrote:

> Ugh, git/git is already a horror to 'ls', adding another n files...
> :(.

They are dotfiles, though depending on how your 'ls' works, that may or
may not help.

> Which brings me back to "if only git had a seperate src/ and maybe
> /build directories" :P.

Hmm, I don’t want to work on that in general, but a separate deps/
directory does not sound like a bad idea at all.

i.e., something vaguely like this.

 .gitignore |    1 +
 Makefile   |   20 ++++++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/.gitignore b/.gitignore
index ac02a58..803247f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -170,6 +170,7 @@
 *.exe
 *.[aos]
 *.py[co]
+*.o.d
 *+
 /config.mak
 /autom4te.cache
diff --git a/Makefile b/Makefile
index ed0f461..1cc149b 100644
--- a/Makefile
+++ b/Makefile
@@ -488,6 +488,7 @@ LIB_H += unpack-trees.h
 LIB_H += userdiff.h
 LIB_H += utf8.h
 LIB_H += wt-status.h
+LIB_H :=
 
 LIB_OBJS += abspath.o
 LIB_OBJS += advice.o
@@ -1559,13 +1560,23 @@ git.o git.spec \
 	$(patsubst %.perl,%,$(SCRIPT_PERL)) \
 	: GIT-VERSION-FILE
 
+dep_file = $(dir $@)deps/$(notdir $@).d
+dep_args = -MF $(dep_file) -MMD -MP
+
 %.o: %.c GIT-CFLAGS
-	$(QUIET_CC)$(CC) -o $*.o -c $(ALL_CFLAGS) $<
+	$(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(ALL_CFLAGS) $<
 %.s: %.c GIT-CFLAGS
 	$(QUIET_CC)$(CC) -S $(ALL_CFLAGS) $<
 %.o: %.S
 	$(QUIET_CC)$(CC) -o $*.o -c $(ALL_CFLAGS) $<
 
+objects := $(wildcard *.o block-sha1/*.o ppc/*.o compat/*.o \
+		compat/*/*.o xdiff/*.o)
+dep_files := $(wildcard $(foreach f,$(objects),$(dir $f)deps/$(notdir $f).d))
+ifneq ($(dep_files),)
+include $(dep_files)
+endif
+
 exec_cmd.o: exec_cmd.c GIT-CFLAGS
 exec_cmd.o: ALL_CFLAGS += \
 	'-DGIT_EXEC_PATH="$(gitexecdir_SQ)"' \
@@ -1657,6 +1668,9 @@ TRACK_CFLAGS = $(subst ','\'',$(ALL_CFLAGS)):\
              $(bindir_SQ):$(gitexecdir_SQ):$(template_dir_SQ):$(prefix_SQ)
 
 GIT-CFLAGS: .FORCE-GIT-CFLAGS
+	mkdir -p deps block-sha1/deps ppc/deps compat/deps \
+		compat/regex/deps compat/nedmalloc/deps compat/fnmatch/deps \
+		xdiff/deps
 	@FLAGS='$(TRACK_CFLAGS)'; \
 	    if test x"$$FLAGS" != x"`cat GIT-CFLAGS 2>/dev/null`" ; then \
 		echo 1>&2 "    * new build flags or prefix"; \
@@ -1873,8 +1887,10 @@ distclean: clean
 	$(RM) configure
 
 clean:
-	$(RM) *.o block-sha1/*.o arm/*.o ppc/*.o compat/*.o compat/*/*.o xdiff/*.o \
+	$(RM) *.o block-sha1/*.o ppc/*.o compat/*.o compat/*/*.o xdiff/*.o \
 		$(LIB_FILE) $(XDIFF_LIB)
+	$(RM) -r deps block-sha1/deps ppc/deps compat/deps \
+		compat/*/deps xdiff/deps
 	$(RM) $(ALL_PROGRAMS) $(BUILT_INS) git$X
 	$(RM) $(TEST_PROGRAMS)
 	$(RM) *.spec *.pyc *.pyo */*.pyc */*.pyo common-cmds.h TAGS tags cscope*
-- 
1.6.5.3