Add a "sparse-incr" target to compliment the existing "sparse"
target. The new "sparse-incr" target doesn't depend on "FORCE", and
will create empty *.sp files as markers for the corresponding *.c file
having been checked.
Those *.sp files in turn depend on the *.o files, so we can be certain
that the dependencies are correct by either depending on all header
files, or under "COMPUTE_HEADER_DEPENDENCIES=yes" the headers the
relevant file needs.
The "sparse-incr" target is slower on a fresh git.git checkout, as it
depends on the creation of the *.o files. But once the *.o and *.sp
files are built it's able to incrementally update them. It's thus
viable to run:
make all sparse-incr
As part of a regular edit/compile/test cycle, or as a fast "git rebase
--exec" command.
On my box (with -j8) the initial run of the "sparse" target takes ~5s,
but ~16s for "sparse-incr". When using CC="ccache cc" the difference
between the two is negligible.
Running e.g.:
make grep.sp
Will behave the same way and will always re-run "cgcc", we'll only use
the new dependency chain of "sparse-incr" is part of the MAKECMDGOALS.
I think it would make sense to just remove the "sparse" target
entirely, and to say that anyone who cares about the speed of an
initial "sparse" run should use "CC='ccache cc'". But per [1] and [2]
there are existing users of "make sparse" and "make <file>.sp" that
prefer the current semantics.
I.e. per [2] want "make <file>.sp" to *always* run "sparse", even
though a corresponding "make <file>.o" would only re-run the "real"
compilation if needed. I don't think that makes any sense, especially
in combination with DEVELOPER=1 which'll ensure that -Werror would
have made any errors in a "make <file>.sp" sticky.
But since we have existing users relying on it, and I don't really
care at al about "make <file>.sp", I just want an incremental target I
can use, let's create this new "make sparse-incr" instead of "fixing"
the existing "make sparse".
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.
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.
1. https://lore.kernel.org/git/xmqqtuib199x.fsf@gitster.g/
2. https://lore.kernel.org/git/457ec039-1e26-9da9-55f6-9ea79b962bfe@xxxxxxxxxxxxxxxxxxxx/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
---
Range-diff against v2:
1: 059829f2195 ! 1: b6ba99ca4cc Makefile: make the "sparse" target non-.PHONY
@@ Metadata
Author: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
## Commit message ##
- 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.
+ Makefile: add a non-.PHONY "sparse-incr" target
+
+ Add a "sparse-incr" target to compliment the existing "sparse"
+ target. The new "sparse-incr" target doesn't depend on "FORCE", and
+ will create empty *.sp files as markers for the corresponding *.c file
+ having been checked.
+
+ Those *.sp files in turn depend on the *.o files, so we can be certain
+ that the dependencies are correct by either depending on all header
+ files, or under "COMPUTE_HEADER_DEPENDENCIES=yes" the headers the
+ relevant file needs.
+
+ The "sparse-incr" target is slower on a fresh git.git checkout, as it
+ depends on the creation of the *.o files. But once the *.o and *.sp
+ files are built it's able to incrementally update them. It's thus
+ viable to run:
+
+ make all sparse-incr
+
+ As part of a regular edit/compile/test cycle, or as a fast "git rebase
+ --exec" command.
+
+ On my box (with -j8) the initial run of the "sparse" target takes ~5s,
+ but ~16s for "sparse-incr". When using CC="ccache cc" the difference
+ between the two is negligible.
+
+ Running e.g.:
+
+ make grep.sp
+
+ Will behave the same way and will always re-run "cgcc", we'll only use
+ the new dependency chain of "sparse-incr" is part of the MAKECMDGOALS.
+
+ I think it would make sense to just remove the "sparse" target
+ entirely, and to say that anyone who cares about the speed of an
+ initial "sparse" run should use "CC='ccache cc'". But per [1] and [2]
+ there are existing users of "make sparse" and "make <file>.sp" that
+ prefer the current semantics.
+
+ I.e. per [2] want "make <file>.sp" to *always* run "sparse", even
+ though a corresponding "make <file>.o" would only re-run the "real"
+ compilation if needed. I don't think that makes any sense, especially
+ in combination with DEVELOPER=1 which'll ensure that -Werror would
+ have made any errors in a "make <file>.sp" sticky.
+
+ But since we have existing users relying on it, and I don't really
+ care at al about "make <file>.sp", I just want an incremental target I
+ can use, let's create this new "make sparse-incr" instead of "fixing"
+ the existing "make sparse".
See 0bcd9ae85d7 (sparse: Fix errors due to missing target-specific
- variables, 2011-04-21) for the modern implementation of the sparse
+ 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 $@ without a move is OK here because we're using the
.DELETE_ON_ERROR Makefile feature. See 7b76d6bf221 (Makefile: add and
use the ".DELETE_ON_ERROR" flag, 2021-06-29). GNU make ensures that on
error this file will be removed.
+ 1. https://lore.kernel.org/git/xmqqtuib199x.fsf@gitster.g/
+ 2. https://lore.kernel.org/git/457ec039-1e26-9da9-55f6-9ea79b962bfe@xxxxxxxxxxxxxxxxxxxx/
+
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
## .gitignore ##
@@ Makefile: check-sha1:: t/helper/test-tool$X
SP_OBJ = $(patsubst %.o,%.sp,$(C_OBJ))
-$(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
-+$(SP_OBJ): %.sp: %.c %.o GIT-CFLAGS
++define cmd_run_sparse
$(QUIET_SP)cgcc -no-compile $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) \
-- $(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $<
-+ -Wsparse-error \
-+ $(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $< && \
-+ >$@
+ $(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $<
++endef
++
++ifneq ($(filter sparse-incr,$(MAKECMDGOALS)),sparse-incr)
++ifneq ($(filter sparse,$(MAKECMDGOALS)),)
++$(error The sparse and sparse-incr targets cannot be combined!)
++endif
++$(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
++ $(cmd_run_sparse)
++else
++$(SP_OBJ): %.sp: %.c %.o GIT-CFLAGS
++ $(cmd_run_sparse) >$@
++endif
-.PHONY: sparse $(SP_OBJ)
-+.PHONY: sparse
++.PHONY: sparse sparse-incr
sparse: $(SP_OBJ)
++sparse-incr: $(SP_OBJ)
EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
+ ifndef GCRYPT_SHA256
@@ Makefile: clean: profile-clean coverage-clean cocciclean
$(RM) $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git$X
$(RM) $(TEST_PROGRAMS)
.gitignore | 1 +
Makefile | 18 ++++++++++++++++--
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/.gitignore b/.gitignore
index 311841f9bed..b02250a50c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -224,6 +224,7 @@
*.lib
*.res
*.sln
+*.sp
*.suo
*.ncb
*.vcproj
diff --git a/Makefile b/Makefile
index a9f9b689f0c..59270d5b056 100644
--- a/Makefile
+++ b/Makefile
@@ -2896,12 +2896,25 @@ check-sha1:: t/helper/test-tool$X
SP_OBJ = $(patsubst %.o,%.sp,$(C_OBJ))
-$(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
+define cmd_run_sparse
$(QUIET_SP)cgcc -no-compile $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) \
$(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $<
+endef
+
+ifneq ($(filter sparse-incr,$(MAKECMDGOALS)),sparse-incr)
+ifneq ($(filter sparse,$(MAKECMDGOALS)),)
+$(error The sparse and sparse-incr targets cannot be combined!)
+endif
+$(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
+ $(cmd_run_sparse)
+else
+$(SP_OBJ): %.sp: %.c %.o GIT-CFLAGS
+ $(cmd_run_sparse) >$@
+endif
-.PHONY: sparse $(SP_OBJ)
+.PHONY: sparse sparse-incr
sparse: $(SP_OBJ)
+sparse-incr: $(SP_OBJ)
EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
ifndef GCRYPT_SHA256
@@ -3227,6 +3240,7 @@ 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/
--
2.33.0.1326.g5e4342b7bef
