diff options
authorÆvar Arnfjörð Bjarmason <>2021-09-23 00:07:16 (GMT)
committerJunio C Hamano <>2021-09-23 04:36:11 (GMT)
commitc234e8a0ecfaa53f88b228e50fafe849402f6c49 (patch)
parent99c99ed8259bf070cd8ae7b51a94904b7cf5c161 (diff)
Makefile: make the "sparse" target non-.PHONY
Change the "sparse" target and its *.sp dependencies to be non-.PHONY. Before this change "make sparse" would take ~5s to re-run all the *.c files through "cgcc", after it it'll create an empty *.sp file sitting alongside the *.c file, only if the *.c file or its dependencies are newer than the *.sp is the *.sp re-made. We ensure that the recursive dependencies are correct by depending on the *.o file, which in turn will have correct dependencies by either depending on all header files, or under "COMPUTE_HEADER_DEPENDENCIES=yes" the headers it needs. This means that a plain "make sparse" is much slower, as we'll now need to make the *.o files just to create the *.sp files, but incrementally creating the *.sp files is *much* faster and less verbose, it thus becomes viable to run "sparse" along with "all" as e.g. "git rebase --exec 'make all sparse'". On my box with -j8 "make sparse" was fast before, or around 5 seconds, now it only takes that long the first time, and the common case is <100ms, or however long it takes GNU make to stat the *.sp file and see that all the corresponding *.c file and its dependencies are older. See 0bcd9ae85d7 (sparse: Fix errors due to missing target-specific variables, 2011-04-21) for the modern implementation of the sparse target being changed here. It is critical that we use -Wsparse-error here, otherwise the error would only show up once, but we'd successfully create the empty *.sp file, and running a second time wouldn't show the error. I'm therefore not putting it into SPARSE_FLAGS or SP_EXTRA_FLAGS, it's not optional, the Makefile logic won't behave properly without it. Appending to $@ without a move is OK here because we're using the .DELETE_ON_ERROR Makefile feature. See 7b76d6bf221 (Makefile: add and use the ".DELETE_ON_ERROR" flag, 2021-06-29). GNU make ensures that on error this file will be removed. Signed-off-by: Ævar Arnfjörð Bjarmason <> Signed-off-by: Junio C Hamano <>
2 files changed, 7 insertions, 3 deletions
diff --git a/.gitignore b/.gitignore
index 311841f..b02250a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -224,6 +224,7 @@
diff --git a/Makefile b/Makefile
index 9df565f..8d085ab 100644
--- a/Makefile
+++ b/Makefile
@@ -2903,11 +2903,13 @@ check-sha1:: t/helper/test-tool$X
SP_OBJ = $(patsubst %.o,%.sp,$(C_OBJ))
-$(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
+$(SP_OBJ): %.sp: %.c %.o GIT-CFLAGS
$(QUIET_SP)cgcc -no-compile $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) \
+ -Wsparse-error \
+ >$@
-.PHONY: sparse $(SP_OBJ)
+.PHONY: sparse
sparse: $(SP_OBJ)
EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
@@ -3234,6 +3236,7 @@ clean: profile-clean coverage-clean cocciclean
+ $(RM) $(SP_OBJ)
$(RM) $(HCC)
$(RM) -r bin-wrappers $(dep_dirs) $(compdb_dir) compile_commands.json
$(RM) -r po/build/