Merge branch 'ab/make-optim-noop'

Makefile refactoring with a bit of suffixes rule stripping to
optimize the runtime overhead.

* ab/make-optim-noop:
  Makefiles: add and use wildcard "mkdir -p" template
  Makefile: add "$(QUIET)" boilerplate to shared.mak
  Makefile: move $(comma), $(empty) and $(space) to shared.mak
  Makefile: move ".SUFFIXES" rule to shared.mak
  Makefile: define $(LIB_H) in terms of $(FIND_SOURCE_FILES)
  Makefile: disable GNU make built-in wildcard rules
  Makefiles: add "shared.mak", move ".DELETE_ON_ERROR" to it
  scalar Makefile: use "The default target of..." pattern

Documentation/Makefile

@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../shared.mak
+
 # Guard against environment variables
 MAN1_TXT =
 MAN5_TXT =
@@ -215,38 +218,6 @@ DEFAULT_EDITOR_SQ = $(subst ','\'',$(DEFAULT_EDITOR))
 ASCIIDOC_EXTRA += -a 'git-default-editor=$(DEFAULT_EDITOR_SQ)'
 endif
 
-QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
-QUIET_SUBDIR1  =
-
-ifneq ($(findstring $(MAKEFLAGS),w),w)
-PRINT_DIR = --no-print-directory
-else # "make -w"
-NO_SUBDIR = :
-endif
-
-ifneq ($(findstring $(MAKEFLAGS),s),s)
-ifndef V
-	QUIET		= @
-	QUIET_ASCIIDOC	= @echo '   ' ASCIIDOC $@;
-	QUIET_XMLTO	= @echo '   ' XMLTO $@;
-	QUIET_DB2TEXI	= @echo '   ' DB2TEXI $@;
-	QUIET_MAKEINFO	= @echo '   ' MAKEINFO $@;
-	QUIET_DBLATEX	= @echo '   ' DBLATEX $@;
-	QUIET_XSLTPROC	= @echo '   ' XSLTPROC $@;
-	QUIET_GEN	= @echo '   ' GEN $@;
-	QUIET_STDERR	= 2> /dev/null
-	QUIET_SUBDIR0	= +@subdir=
-	QUIET_SUBDIR1	= ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
-			  $(MAKE) $(PRINT_DIR) -C $$subdir
-
-	QUIET_LINT_GITLINK	= @echo '   ' LINT GITLINK $<;
-	QUIET_LINT_MANSEC	= @echo '   ' LINT MAN SEC $<;
-	QUIET_LINT_MANEND	= @echo '   ' LINT MAN END $<;
-
-	export V
-endif
-endif
-
 all: html man
 
 html: $(DOC_HTML)
@@ -463,25 +434,11 @@ quick-install-html: require-htmlrepo
 print-man1:
 	@for i in $(MAN1_TXT); do echo $$i; done
 
-## Lint: Common
-.build:
-	$(QUIET)mkdir $@
-.build/lint-docs: | .build
-	$(QUIET)mkdir $@
-
 ## Lint: gitlink
-.build/lint-docs/gitlink: | .build/lint-docs
-	$(QUIET)mkdir $@
-.build/lint-docs/gitlink/howto: | .build/lint-docs/gitlink
-	$(QUIET)mkdir $@
-.build/lint-docs/gitlink/config: | .build/lint-docs/gitlink
-	$(QUIET)mkdir $@
 LINT_DOCS_GITLINK = $(patsubst %.txt,.build/lint-docs/gitlink/%.ok,$(HOWTO_TXT) $(DOC_DEP_TXT))
-$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink
-$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/howto
-$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/config
 $(LINT_DOCS_GITLINK): lint-gitlink.perl
 $(LINT_DOCS_GITLINK): .build/lint-docs/gitlink/%.ok: %.txt
+	$(call mkdir_p_parent_template)
 	$(QUIET_LINT_GITLINK)$(PERL_PATH) lint-gitlink.perl \
 		$< \
 		$(HOWTO_TXT) $(DOC_DEP_TXT) \
@@ -492,23 +449,18 @@ $(LINT_DOCS_GITLINK): .build/lint-docs/gitlink/%.ok: %.txt
 lint-docs-gitlink: $(LINT_DOCS_GITLINK)
 
 ## Lint: man-end-blurb
-.build/lint-docs/man-end-blurb: | .build/lint-docs
-	$(QUIET)mkdir $@
 LINT_DOCS_MAN_END_BLURB = $(patsubst %.txt,.build/lint-docs/man-end-blurb/%.ok,$(MAN_TXT))
-$(LINT_DOCS_MAN_END_BLURB): | .build/lint-docs/man-end-blurb
 $(LINT_DOCS_MAN_END_BLURB): lint-man-end-blurb.perl
 $(LINT_DOCS_MAN_END_BLURB): .build/lint-docs/man-end-blurb/%.ok: %.txt
+	$(call mkdir_p_parent_template)
 	$(QUIET_LINT_MANEND)$(PERL_PATH) lint-man-end-blurb.perl $< >$@
 .PHONY: lint-docs-man-end-blurb
-lint-docs-man-end-blurb: $(LINT_DOCS_MAN_END_BLURB)
 
 ## Lint: man-section-order
-.build/lint-docs/man-section-order: | .build/lint-docs
-	$(QUIET)mkdir $@
 LINT_DOCS_MAN_SECTION_ORDER = $(patsubst %.txt,.build/lint-docs/man-section-order/%.ok,$(MAN_TXT))
-$(LINT_DOCS_MAN_SECTION_ORDER): | .build/lint-docs/man-section-order
 $(LINT_DOCS_MAN_SECTION_ORDER): lint-man-section-order.perl
 $(LINT_DOCS_MAN_SECTION_ORDER): .build/lint-docs/man-section-order/%.ok: %.txt
+	$(call mkdir_p_parent_template)
 	$(QUIET_LINT_MANSEC)$(PERL_PATH) lint-man-section-order.perl $< >$@
 .PHONY: lint-docs-man-section-order
 lint-docs-man-section-order: $(LINT_DOCS_MAN_SECTION_ORDER)
@@ -524,7 +476,4 @@ doc-l10n install-l10n::
 	$(MAKE) -C po $@
 endif
 
-# Delete the target file on error
-.DELETE_ON_ERROR:
-
 .PHONY: FORCE

Makefile

@@ -1,6 +1,9 @@
 # The default target of this Makefile is...
 all::
 
+# Import tree-wide shared Makefile behavior and libraries
+include shared.mak
+
 # Define V=1 to have a more verbose compile.
 #
 # Define SHELL_PATH to a POSIX shell if your /bin/sh is broken.
@@ -830,12 +833,33 @@ GENERATED_H += hook-list.h
 .PHONY: generated-hdrs
 generated-hdrs: $(GENERATED_H)
 
-LIB_H := $(sort $(patsubst ./%,%,$(shell git ls-files '*.h' ':!t/' ':!Documentation/' 2>/dev/null || \
+## Exhaustive lists of our source files, either dynamically generated,
+## or hardcoded.
+SOURCES_CMD = ( \
+	git ls-files \
+		'*.[hcS]' \
+		'*.sh' \
+		':!*[tp][0-9][0-9][0-9][0-9]*' \
+		':!contrib' \
+		2>/dev/null || \
 	$(FIND) . \
-	-name .git -prune -o \
+		\( -name .git -type d -prune \) \
-	-name t -prune -o \
+		-o \( -name '[tp][0-9][0-9][0-9][0-9]*' -prune \) \
-	-name Documentation -prune -o \
+		-o \( -name contrib -type d -prune \) \
-	-name '*.h' -print)))
+		-o \( -name build -type d -prune \) \
+		-o \( -name 'trash*' -type d -prune \) \
+		-o \( -name '*.[hcS]' -type f -print \) \
+		-o \( -name '*.sh' -type f -print \) \
+		| sed -e 's|^\./||' \
+	)
+FOUND_SOURCE_FILES := $(shell $(SOURCES_CMD))
+
+FOUND_C_SOURCES = $(filter %.c,$(FOUND_SOURCE_FILES))
+FOUND_H_SOURCES = $(filter %.h,$(FOUND_SOURCE_FILES))
+
+COCCI_SOURCES = $(filter-out $(THIRD_PARTY_SOURCES),$(FOUND_C_SOURCES))
+
+LIB_H = $(FOUND_H_SOURCES)
 
 LIB_OBJS += abspath.o
 LIB_OBJS += add-interactive.o
@@ -1265,10 +1289,6 @@ endif
 ALL_CFLAGS = $(DEVELOPER_CFLAGS) $(CPPFLAGS) $(CFLAGS)
 ALL_LDFLAGS = $(LDFLAGS)
 
-comma := ,
-empty :=
-space := $(empty) $(empty)
-
 ifdef SANITIZE
 SANITIZERS := $(foreach flag,$(subst $(comma),$(space),$(SANITIZE)),$(flag))
 BASIC_CFLAGS += -fsanitize=$(SANITIZE) -fno-sanitize-recover=$(SANITIZE)
@@ -1981,39 +2001,6 @@ ifndef PAGER_ENV
 PAGER_ENV = LESS=FRX LV=-c
 endif
 
-QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
-QUIET_SUBDIR1  =
-
-ifneq ($(findstring w,$(MAKEFLAGS)),w)
-PRINT_DIR = --no-print-directory
-else # "make -w"
-NO_SUBDIR = :
-endif
-
-ifneq ($(findstring s,$(MAKEFLAGS)),s)
-ifndef V
-	QUIET_CC       = @echo '   ' CC $@;
-	QUIET_AR       = @echo '   ' AR $@;
-	QUIET_LINK     = @echo '   ' LINK $@;
-	QUIET_BUILT_IN = @echo '   ' BUILTIN $@;
-	QUIET_GEN      = @echo '   ' GEN $@;
-	QUIET_LNCP     = @echo '   ' LN/CP $@;
-	QUIET_XGETTEXT = @echo '   ' XGETTEXT $@;
-	QUIET_MSGFMT   = @echo '   ' MSGFMT $@;
-	QUIET_GCOV     = @echo '   ' GCOV $@;
-	QUIET_SP       = @echo '   ' SP $<;
-	QUIET_HDR      = @echo '   ' HDR $(<:hcc=h);
-	QUIET_RC       = @echo '   ' RC $@;
-	QUIET_SPATCH   = @echo '   ' SPATCH $<;
-	QUIET_SUBDIR0  = +@subdir=
-	QUIET_SUBDIR1  = ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
-			 $(MAKE) $(PRINT_DIR) -C $$subdir
-	export V
-	export QUIET_GEN
-	export QUIET_BUILT_IN
-endif
-endif
-
 ifdef NO_INSTALL_HARDLINKS
 	export NO_INSTALL_HARDLINKS
 endif
@@ -2194,16 +2181,6 @@ shell_compatibility_test: please_set_SHELL_PATH_to_a_more_modern_shell
 strip: $(PROGRAMS) git$X
 	$(STRIP) $(STRIP_OPTS) $^
 
-### Flags affecting all rules
-
-# A GNU make extension since gmake 3.72 (released in late 1994) to
-# remove the target of rules if commands in those rules fail. The
-# default is to only do that if make itself receives a signal. Affects
-# all targets, see:
-#
-#    info make --index-search=.DELETE_ON_ERROR
-.DELETE_ON_ERROR:
-
 ### Target-specific flags and dependencies
 
 # The generic compilation pattern rule and automatically
@@ -2566,8 +2543,6 @@ ASM_SRC := $(wildcard $(OBJECTS:o=S))
 ASM_OBJ := $(ASM_SRC:S=o)
 C_OBJ := $(filter-out $(ASM_OBJ),$(OBJECTS))
 
-.SUFFIXES:
-
 $(C_OBJ): %.o: %.c GIT-CFLAGS $(missing_dep_dirs) $(missing_compdb_dir)
 	$(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(compdb_args) $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $<
 $(ASM_OBJ): %.o: %.S GIT-CFLAGS $(missing_dep_dirs) $(missing_compdb_dir)
@@ -2770,7 +2745,8 @@ all:: $(MOFILES)
 endif
 
 po/build/locale/%/LC_MESSAGES/git.mo: po/%.po
-	$(QUIET_MSGFMT)mkdir -p $(dir $@) && $(MSGFMT) -o $@ $<
+	$(call mkdir_p_parent_template)
+	$(QUIET_MSGFMT)$(MSGFMT) -o $@ $<
 
 LIB_PERL := $(wildcard perl/Git.pm perl/Git/*.pm perl/Git/*/*.pm perl/Git/*/*/*.pm)
 LIB_PERL_GEN := $(patsubst perl/%.pm,perl/build/lib/%.pm,$(LIB_PERL))
@@ -2786,35 +2762,16 @@ NO_PERL_CPAN_FALLBACKS_SQ = $(subst ','\'',$(NO_PERL_CPAN_FALLBACKS))
 endif
 
 perl/build/lib/%.pm: perl/%.pm GIT-PERL-DEFINES
-	$(QUIET_GEN)mkdir -p $(dir $@) && \
+	$(call mkdir_p_parent_template)
+	$(QUIET_GEN) \
 	sed -e 's|@@LOCALEDIR@@|$(perl_localedir_SQ)|g' \
 	    -e 's|@@NO_GETTEXT@@|$(NO_GETTEXT_SQ)|g' \
 	    -e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(NO_PERL_CPAN_FALLBACKS_SQ)|g' \
 	< $< > $@
 
 perl/build/man/man3/Git.3pm: perl/Git.pm
-	$(QUIET_GEN)mkdir -p $(dir $@) && \
+	$(call mkdir_p_parent_template)
-	pod2man $< $@
+	$(QUIET_GEN)pod2man $< $@
-
-FIND_SOURCE_FILES = ( \
-	git ls-files \
-		'*.[hcS]' \
-		'*.sh' \
-		':!*[tp][0-9][0-9][0-9][0-9]*' \
-		':!contrib' \
-		2>/dev/null || \
-	$(FIND) . \
-		\( -name .git -type d -prune \) \
-		-o \( -name '[tp][0-9][0-9][0-9][0-9]*' -prune \) \
-		-o \( -name contrib -type d -prune \) \
-		-o \( -name build -type d -prune \) \
-		-o \( -name 'trash*' -type d -prune \) \
-		-o \( -name '*.[hcS]' -type f -print \) \
-		-o \( -name '*.sh' -type f -print \) \
-		| sed -e 's|^\./||' \
-	)
-
-FOUND_SOURCE_FILES = $(shell $(FIND_SOURCE_FILES))
 
 $(ETAGS_TARGET): $(FOUND_SOURCE_FILES)
 	$(QUIET_GEN)$(RM) $@+ && \
@@ -2948,7 +2905,7 @@ test_bindir_programs := $(patsubst %,bin-wrappers/%,$(BINDIR_PROGRAMS_NEED_X) $(
 all:: $(TEST_PROGRAMS) $(test_bindir_programs)
 
 bin-wrappers/%: wrap-for-bin.sh
-	@mkdir -p bin-wrappers
+	$(call mkdir_p_parent_template)
 	$(QUIET_GEN)sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \
 	     -e 's|@@BUILD_DIR@@|$(shell pwd)|' \
 	     -e 's|@@PROG@@|$(patsubst test-%,t/helper/test-%$(X),$(@F))$(patsubst git%,$(X),$(filter $(@F),$(BINDIR_PROGRAMS_NEED_X)))|' < $< > $@ && \
@@ -3025,9 +2982,6 @@ check: $(GENERATED_H)
 		exit 1; \
 	fi
 
-FOUND_C_SOURCES = $(filter %.c,$(FOUND_SOURCE_FILES))
-COCCI_SOURCES = $(filter-out $(THIRD_PARTY_SOURCES),$(FOUND_C_SOURCES))
-
 %.cocci.patch: %.cocci $(COCCI_SOURCES)
 	$(QUIET_SPATCH) \
 	if test $(SPATCH_BATCH_SIZE) = 0; then \

config.mak.uname

@@ -727,7 +727,6 @@ vcxproj:
 	git diff-index --cached --quiet HEAD --
 
 	# Make .vcxproj files and add them
-	unset QUIET_GEN QUIET_BUILT_IN; \
 	perl contrib/buildsystems/generate -g Vcxproj
 	git add -f git.sln {*,*/lib,t/helper/*}/*.vcxproj
 

contrib/scalar/Makefile

@@ -1,18 +1,8 @@
-QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
+# The default target of this Makefile is...
-QUIET_SUBDIR1  =
+all::
 
-ifneq ($(findstring s,$(MAKEFLAGS)),s)
+# Import tree-wide shared Makefile behavior and libraries
-ifndef V
+include ../../shared.mak
-	QUIET_GEN      = @echo '   ' GEN $@;
-	QUIET_SUBDIR0  = +@subdir=
-	QUIET_SUBDIR1  = ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
-			 $(MAKE) $(PRINT_DIR) -C $$subdir
-else
-	export V
-endif
-endif
-
-all:
 
 include ../../config.mak.uname
 -include ../../config.mak.autogen

contrib/scalar/t/Makefile

@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../../../shared.mak
+
 # Run scalar tests
 #
 # Copyright (c) 2005,2021 Junio C Hamano, Johannes Schindelin

shared.mak

@@ -0,0 +1,103 @@
+### Remove GNU make implicit rules
+
+## This speeds things up since we don't need to look for and stat() a
+## "foo.c,v" every time a rule referring to "foo.c" is in play. See
+## "make -p -f/dev/null | grep ^%::'".
+%:: %,v
+%:: RCS/%,v
+%:: RCS/%
+%:: s.%
+%:: SCCS/s.%
+
+## Likewise delete default $(SUFFIXES). See:
+##
+##     info make --index-search=.SUFFIXES
+.SUFFIXES:
+
+### Flags affecting all rules
+
+# A GNU make extension since gmake 3.72 (released in late 1994) to
+# remove the target of rules if commands in those rules fail. The
+# default is to only do that if make itself receives a signal. Affects
+# all targets, see:
+#
+#    info make --index-search=.DELETE_ON_ERROR
+.DELETE_ON_ERROR:
+
+### Global variables
+
+## comma, empty, space: handy variables as these tokens are either
+## special or can be hard to spot among other Makefile syntax.
+comma := ,
+empty :=
+space := $(empty) $(empty)
+
+### Quieting
+## common
+QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
+QUIET_SUBDIR1  =
+
+ifneq ($(findstring w,$(MAKEFLAGS)),w)
+PRINT_DIR = --no-print-directory
+else # "make -w"
+NO_SUBDIR = :
+endif
+
+ifneq ($(findstring s,$(MAKEFLAGS)),s)
+ifndef V
+## common
+	QUIET_SUBDIR0  = +@subdir=
+	QUIET_SUBDIR1  = ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
+			 $(MAKE) $(PRINT_DIR) -C $$subdir
+
+	QUIET          = @
+	QUIET_GEN      = @echo '   ' GEN $@;
+
+	QUIET_MKDIR_P_PARENT  = @echo $(wspfx_SQ) MKDIR -p $(@D);
+
+## Used in "Makefile"
+	QUIET_CC       = @echo '   ' CC $@;
+	QUIET_AR       = @echo '   ' AR $@;
+	QUIET_LINK     = @echo '   ' LINK $@;
+	QUIET_BUILT_IN = @echo '   ' BUILTIN $@;
+	QUIET_LNCP     = @echo '   ' LN/CP $@;
+	QUIET_XGETTEXT = @echo '   ' XGETTEXT $@;
+	QUIET_MSGFMT   = @echo '   ' MSGFMT $@;
+	QUIET_GCOV     = @echo '   ' GCOV $@;
+	QUIET_SP       = @echo '   ' SP $<;
+	QUIET_HDR      = @echo '   ' HDR $(<:hcc=h);
+	QUIET_RC       = @echo '   ' RC $@;
+	QUIET_SPATCH   = @echo '   ' SPATCH $<;
+
+## Used in "Documentation/Makefile"
+	QUIET_ASCIIDOC	= @echo '   ' ASCIIDOC $@;
+	QUIET_XMLTO	= @echo '   ' XMLTO $@;
+	QUIET_DB2TEXI	= @echo '   ' DB2TEXI $@;
+	QUIET_MAKEINFO	= @echo '   ' MAKEINFO $@;
+	QUIET_DBLATEX	= @echo '   ' DBLATEX $@;
+	QUIET_XSLTPROC	= @echo '   ' XSLTPROC $@;
+	QUIET_GEN	= @echo '   ' GEN $@;
+	QUIET_STDERR	= 2> /dev/null
+
+	QUIET_LINT_GITLINK	= @echo '   ' LINT GITLINK $<;
+	QUIET_LINT_MANSEC	= @echo '   ' LINT MAN SEC $<;
+	QUIET_LINT_MANEND	= @echo '   ' LINT MAN END $<;
+
+	export V
+endif
+endif
+
+### Templates
+
+## mkdir_p_parent: lazily "mkdir -p" the path needed for a $@
+## file. Uses $(wildcard) to avoid the "mkdir -p" if it's not
+## needed.
+##
+## Is racy, but in a good way; we might redundantly (and safely)
+## "mkdir -p" when running in parallel, but won't need to exhaustively create
+## individual rules for "a" -> "prefix" -> "dir" -> "file" if given a
+## "a/prefix/dir/file". This can instead be inserted at the start of
+## the "a/prefix/dir/file" rule.
+define mkdir_p_parent_template
+$(if $(wildcard $(@D)),,$(QUIET_MKDIR_P_PARENT)$(shell mkdir -p $(@D)))
+endef

t/Makefile

@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../shared.mak
+
 # Run tests
 #
 # Copyright (c) 2005 Junio C Hamano

t/interop/Makefile

@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../../shared.mak
+
 -include ../../config.mak
 export GIT_TEST_OPTIONS
 

t/perf/Makefile

@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../../shared.mak
+
 -include ../../config.mak
 export GIT_TEST_OPTIONS
 

templates/Makefile

@@ -1,9 +1,7 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../shared.mak
+
 # make and install sample templates
-
-ifndef V
-	QUIET = @
-endif
-
 INSTALL ?= install
 TAR ?= tar
 RM ?= rm -f