From c234e8a0ecfaa53f88b228e50fafe849402f6c49 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Date: Thu, 23 Sep 2021 02:07:16 +0200 Subject: Makefile: make the "sparse" target non-.PHONY MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 $@ without a move is OK here because we're using the .DELETE_ON_ERROR Makefile feature. See 7b76d6bf221 (Makefile: add and use the ".DELETE_ON_ERROR" flag, 2021-06-29). GNU make ensures that on error this file will be removed. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano --- .gitignore | 1 + Makefile | 9 ++++++--- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/.gitignore b/.gitignore index 311841f9be..b02250a50c 100644 --- a/.gitignore +++ b/.gitignore @@ -224,6 +224,7 @@ *.lib *.res *.sln +*.sp *.suo *.ncb *.vcproj diff --git a/Makefile b/Makefile index 9df565f27b..8d085ab72a 100644 --- a/Makefile +++ b/Makefile @@ -2903,11 +2903,13 @@ check-sha1:: t/helper/test-tool$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) \ - $(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $< + -Wsparse-error \ + $(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $< && \ + >$@ -.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) $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git$X $(RM) $(TEST_PROGRAMS) $(RM) $(FUZZ_PROGRAMS) + $(RM) $(SP_OBJ) $(RM) $(HCC) $(RM) -r bin-wrappers $(dep_dirs) $(compdb_dir) compile_commands.json $(RM) -r po/build/ -- cgit v1.2.3