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| author | Ævar Arnfjörð Bjarmason <avarab@gmail.com> | 2021-09-23 03:07:16 +0300 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2021-09-23 07:36:11 +0300 |
| commit | c234e8a0ecfaa53f88b228e50fafe849402f6c49 (patch) | |
| tree | 18e0d2424b9da89d4044a0839091e70754923bf7 /.gitignore | |
| parent | 99c99ed8259bf070cd8ae7b51a94904b7cf5c161 (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 <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to '.gitignore')
| -rw-r--r-- | .gitignore | 1 |
1 files changed, 1 insertions, 0 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 |