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 <avarab@xxxxxxxxx>
---
Range-diff against v1:
1: e03fde1b642 ! 1: 059829f2195 Makefile: make the "sparse" target non-.PHONY
@@ Commit message
Makefile: make the "sparse" target non-.PHONY
Change the "sparse" target and its *.sp dependencies to be
- non-.PHONY. It's now viable to run it as part of a normal compilation
- target, as we'll only re-generate these checks if the source *.c file
- has changed.
+ 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.
- On my box with -j8 it 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 files are older.
+ 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
@@ Makefile: 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 GIT-CFLAGS
++$(SP_OBJ): %.sp: %.c %.o GIT-CFLAGS
$(QUIET_SP)cgcc -no-compile $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) \
- $(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $<
+ -Wsparse-error \
@@ Makefile: check-sha1:: t/helper/test-tool$X
sparse: $(SP_OBJ)
EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
+@@ Makefile: 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
+ $(RM) -r po/build/
2: 9c4cedacdce < -: ----------- Makefile: do one append in %.hcc rule
3: e2ad1700f9e < -: ----------- Makefile: make the "hdr-check" target non-.PHONY
.gitignore | 1 +
Makefile | 9 ++++++---
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/.gitignore b/.gitignore
index 311841f9bed..b02250a50c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -224,6 +224,7 @@
*.lib
*.res
*.sln
+*.sp
*.suo
*.ncb
*.vcproj
diff --git a/Makefile b/Makefile
index a9f9b689f0c..0bae65889fe 100644
--- a/Makefile
+++ b/Makefile
@@ -2896,11 +2896,13 @@ check-sha1:: t/helper/test-tool$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/%
@@ -3227,6 +3229,7 @@ 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/
--
2.33.0.1225.g9f062250122
