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0b6d0bc924
Add a template to do the "mkdir -p" of $(@D) (the parent dir of $@) for us, and use it for the "make lint-docs" targets I added in8650c6298c(doc lint: make "lint-docs" non-.PHONY, 2021-10-15). As seen in4c64fb5aad(Documentation/Makefile: fix lint-docs mkdir dependency, 2021-10-26) maintaining these manual lists of parent directory dependencies is fragile, in addition to being obviously verbose. I used this pattern at the time because I couldn't find another method than "order-only" prerequisites to avoid doing a "mkdir -p $(@D)" for every file being created, which as noted in [1] would be significantly slower. But as it turns out we can use this neat trick of only doing a "mkdir -p" if the $(wildcard) macro tells us the path doesn't exist. A re-run of a performance test similar to that noted downthread of [1] in [2] shows that this is faster, in addition to being less verbose and more reliable (this uses my "git-hyperfine" thin wrapper for "hyperfine"[3]): $ git -c hyperfine.hook.setup= hyperfine -L rev HEAD~1,HEAD~0 -s 'make -C Documentation lint-docs' -p 'rm -rf Documentation/.build' 'make -C Documentation -j1 lint-docs' Benchmark 1: make -C Documentation -j1 lint-docs' in 'HEAD~1 Time (mean ± σ): 2.914 s ± 0.062 s [User: 2.449 s, System: 0.489 s] Range (min … max): 2.834 s … 3.020 s 10 runs Benchmark 2: make -C Documentation -j1 lint-docs' in 'HEAD~0 Time (mean ± σ): 2.315 s ± 0.062 s [User: 1.950 s, System: 0.386 s] Range (min … max): 2.229 s … 2.397 s 10 runs Summary 'make -C Documentation -j1 lint-docs' in 'HEAD~0' ran 1.26 ± 0.04 times faster than 'make -C Documentation -j1 lint-docs' in 'HEAD~1' So let's use that pattern both for the "lint-docs" target, and a few miscellaneous other targets. This method of creating parent directories is explicitly racy in that we don't know if we're going to say always create a "foo" followed by a "foo/bar" under parallelism, or skip the "foo" because we created "foo/bar" first. In this case it doesn't matter for anything except that we aren't guaranteed to get the same number of rules firing when running make in parallel. 1. https://lore.kernel.org/git/211028.861r45y3pt.gmgdl@evledraar.gmail.com/ 2. https://lore.kernel.org/git/211028.86o879vvtp.gmgdl@evledraar.gmail.com/ 3. https://gitlab.com/avar/git-hyperfine/ Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
104 lines
2.9 KiB
Makefile
104 lines
2.9 KiB
Makefile
### Remove GNU make implicit rules
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## This speeds things up since we don't need to look for and stat() a
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## "foo.c,v" every time a rule referring to "foo.c" is in play. See
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## "make -p -f/dev/null | grep ^%::'".
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%:: %,v
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%:: RCS/%,v
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%:: RCS/%
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%:: s.%
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%:: SCCS/s.%
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## Likewise delete default $(SUFFIXES). See:
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##
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## info make --index-search=.SUFFIXES
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.SUFFIXES:
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### Flags affecting all rules
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# A GNU make extension since gmake 3.72 (released in late 1994) to
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# remove the target of rules if commands in those rules fail. The
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# default is to only do that if make itself receives a signal. Affects
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# all targets, see:
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#
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# info make --index-search=.DELETE_ON_ERROR
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.DELETE_ON_ERROR:
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### Global variables
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## comma, empty, space: handy variables as these tokens are either
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## special or can be hard to spot among other Makefile syntax.
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comma := ,
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empty :=
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space := $(empty) $(empty)
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### Quieting
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## common
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QUIET_SUBDIR0 = +$(MAKE) -C # space to separate -C and subdir
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QUIET_SUBDIR1 =
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ifneq ($(findstring w,$(MAKEFLAGS)),w)
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PRINT_DIR = --no-print-directory
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else # "make -w"
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NO_SUBDIR = :
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endif
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ifneq ($(findstring s,$(MAKEFLAGS)),s)
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ifndef V
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## common
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QUIET_SUBDIR0 = +@subdir=
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QUIET_SUBDIR1 = ;$(NO_SUBDIR) echo ' ' SUBDIR $$subdir; \
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$(MAKE) $(PRINT_DIR) -C $$subdir
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QUIET = @
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QUIET_GEN = @echo ' ' GEN $@;
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QUIET_MKDIR_P_PARENT = @echo $(wspfx_SQ) MKDIR -p $(@D);
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## Used in "Makefile"
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QUIET_CC = @echo ' ' CC $@;
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QUIET_AR = @echo ' ' AR $@;
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QUIET_LINK = @echo ' ' LINK $@;
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QUIET_BUILT_IN = @echo ' ' BUILTIN $@;
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QUIET_LNCP = @echo ' ' LN/CP $@;
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QUIET_XGETTEXT = @echo ' ' XGETTEXT $@;
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QUIET_MSGFMT = @echo ' ' MSGFMT $@;
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QUIET_GCOV = @echo ' ' GCOV $@;
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QUIET_SP = @echo ' ' SP $<;
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QUIET_HDR = @echo ' ' HDR $(<:hcc=h);
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QUIET_RC = @echo ' ' RC $@;
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QUIET_SPATCH = @echo ' ' SPATCH $<;
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## Used in "Documentation/Makefile"
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QUIET_ASCIIDOC = @echo ' ' ASCIIDOC $@;
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QUIET_XMLTO = @echo ' ' XMLTO $@;
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QUIET_DB2TEXI = @echo ' ' DB2TEXI $@;
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QUIET_MAKEINFO = @echo ' ' MAKEINFO $@;
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QUIET_DBLATEX = @echo ' ' DBLATEX $@;
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QUIET_XSLTPROC = @echo ' ' XSLTPROC $@;
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QUIET_GEN = @echo ' ' GEN $@;
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QUIET_STDERR = 2> /dev/null
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QUIET_LINT_GITLINK = @echo ' ' LINT GITLINK $<;
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QUIET_LINT_MANSEC = @echo ' ' LINT MAN SEC $<;
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QUIET_LINT_MANEND = @echo ' ' LINT MAN END $<;
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export V
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endif
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endif
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### Templates
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## mkdir_p_parent: lazily "mkdir -p" the path needed for a $@
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## file. Uses $(wildcard) to avoid the "mkdir -p" if it's not
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## needed.
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##
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## Is racy, but in a good way; we might redundantly (and safely)
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## "mkdir -p" when running in parallel, but won't need to exhaustively create
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## individual rules for "a" -> "prefix" -> "dir" -> "file" if given a
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## "a/prefix/dir/file". This can instead be inserted at the start of
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## the "a/prefix/dir/file" rule.
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define mkdir_p_parent_template
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$(if $(wildcard $(@D)),,$(QUIET_MKDIR_P_PARENT)$(shell mkdir -p $(@D)))
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endef
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