[v5,0/8] Makefile: optimize noop runs, add shared.mak

Message

Ævar Arnfjörð Bjarmason March 3, 2022, 4:04 p.m. UTC

As the v1 notes (among other things):
https://lore.kernel.org/git/[e-mail]/

    This speeds up noop runs of "make" by a lot. After a "make" running a
    "make -j1" with this is ~1.5 faster than on "master"[2], and around 3x
    as fast with "make -j1 NO_TCLTK=Y" (the TCL part takes a lot of time,
    but that's another matter).

This v5 re-roll (for v3, see:
https://lore.kernel.org/git/[e-mail]/):

 * Drops the "wspfx" patch.
 * Rephrases the 1/8 commit message, dropping the mention of .DEFAULT_GOAL etc.

I think this should be ready to advance now per Junio's comment on v4
(https://lore.kernel.org/git/xmqqpmn4jdhy.fsf@gitster.g/):

    Other than a few things I noticed and commented on, 1-7 and 9
    looked all sensible.

Ævar Arnfjörð Bjarmason (8):
  scalar Makefile: use "The default target of..." pattern
  Makefiles: add "shared.mak", move ".DELETE_ON_ERROR" to it
  Makefile: disable GNU make built-in wildcard rules
  Makefile: define $(LIB_H) in terms of $(FIND_SOURCE_FILES)
  Makefile: move ".SUFFIXES" rule to shared.mak
  Makefile: move $(comma), $(empty) and $(space) to shared.mak
  Makefile: add "$(QUIET)" boilerplate to shared.mak
  Makefiles: add and use wildcard "mkdir -p" template

 Documentation/Makefile    |  63 ++------------------
 Makefile                  | 118 ++++++++++++--------------------------
 config.mak.uname          |   1 -
 contrib/scalar/Makefile   |  20 ++-----
 contrib/scalar/t/Makefile |   3 +
 shared.mak                | 103 +++++++++++++++++++++++++++++++++
 t/Makefile                |   3 +
 t/interop/Makefile        |   3 +
 t/perf/Makefile           |   3 +
 templates/Makefile        |   8 +--
 10 files changed, 165 insertions(+), 160 deletions(-)
 create mode 100644 shared.mak

Range-diff against v4:
 1:  26c6bb897cf !  1:  7547bf3e481 scalar Makefile: use "The default target of..." pattern
    @@ Metadata
      ## Commit message ##
         scalar Makefile: use "The default target of..." pattern
     
    -    Make have the "contrib/scalar/Makefile" be stylistically consistent
    -    with the top-level "Makefile" in first declaring "all" to be the
    -    default rule, follwed by including other Makefile snippets.
    +    Make the "contrib/scalar/Makefile" be stylistically consistent with
    +    the top-level "Makefile" in first declaring "all" to be the default
    +    rule, followed by including other Makefile snippets.
     
         This adjusts code added in 0a43fb22026 (scalar: create a rudimentary
    -    executable, 2021-12-03), it's a style-only change, in a subsequent
    -    commit the "QUIET" boilerplate at the beginning of this file will be
    -    retrieved via an include, and having an "all:" between the two set of
    -    "include"'s after that change would look odd.
    -
    -    As noted in [1] using ".DEFAULT_GOAL = all" is another way to do this
    -    in more modern GNU make versions, which we already have a hard
    -    dependency on, but let's leave any such change for a future
    -    improvement and go with using our established pattern consistently for
    -    now.
    -
    -    1. https://lore.kernel.org/git/[e-mail]/
    +    executable, 2021-12-03), it further ensures that when we add another
    +    "include" file in a subsequent commit that the included file won't be
    +    the one to define our default target.
     
         Signed-off-by: Ævar Arnfjörð Bjarmason <[e-mail]>
     
 2:  74692458b70 =  2:  91795eccc32 Makefiles: add "shared.mak", move ".DELETE_ON_ERROR" to it
 3:  0fbdeeffc7b =  3:  9f42f40b518 Makefile: disable GNU make built-in wildcard rules
 4:  ea6b835308a =  4:  034779ff7fb Makefile: define $(LIB_H) in terms of $(FIND_SOURCE_FILES)
 5:  c2339694cf7 =  5:  18e0a6985f1 Makefile: move ".SUFFIXES" rule to shared.mak
 6:  741fdfd48e2 =  6:  422dee02ae9 Makefile: move $(comma), $(empty) and $(space) to shared.mak
 7:  a723cbce270 =  7:  21bf1e6e01c Makefile: add "$(QUIET)" boilerplate to shared.mak
 8:  3733b0c8df1 <  -:  ----------- Makefile: use $(wspfx) for $(QUIET...) in shared.mak
 9:  4cc4aeabb20 !  8:  e6a93cae81d Makefiles: add and use wildcard "mkdir -p" template
    @@ Makefile: test_bindir_programs := $(patsubst %,bin-wrappers/%,$(BINDIR_PROGRAMS_
      ## shared.mak ##
     @@ shared.mak: ifndef V
      	QUIET          = @
    - 	QUIET_GEN      = @echo $(wspfx_SQ) GEN $@;
    + 	QUIET_GEN      = @echo '   ' GEN $@;
      
     +	QUIET_MKDIR_P_PARENT  = @echo $(wspfx_SQ) MKDIR -p $(@D);
     +
      ## Used in "Makefile"
    - 	QUIET_CC       = @echo $(wspfx_SQ) CC $@;
    - 	QUIET_AR       = @echo $(wspfx_SQ) AR $@;
    + 	QUIET_CC       = @echo '   ' CC $@;
    + 	QUIET_AR       = @echo '   ' AR $@;
     @@ shared.mak: ifndef V
      	export V
      endif