[PATCH v2] Makefile: add option to disable automatic dependency generation
- From
Jonathan Nieder <jrnieder@gmail.com>
- Date
- Nov 18, 2011, 09:58 UTC
- Message-ID
- <20111118095820.GF25145@elie.hsd1.il.comcast.net>
- In-Reply-To
- <7vty62klg9.fsf@alter.siamese.dyndns.org>
Now that the COMPUTE_HEADER_DEPENDENCIES feature is turned on automatically for compilers that support it (see v1.7.8-rc0~142^2~1, 2011-08-18), there is no easy way to force it off. For example, setting COMPUTE_HEADER_DEPENDENCIES to the empty string in config.mak just tells the makefile to treat it as undefined and run a test command to see if the -MMD option is supported.
So allow setting COMPUTE_HEADER_DEPENDENCIES=no to explicitly force the feature off. The new semantics:
- "yes" means to explicitly enable the feature - "no" means to disable it - "auto" means to autodetect
The default is still "auto". Any value other than these three will cause the build to error out with a descriptive message so typos and stale settings in config.mak don't result in mysterious behavior.
Makefile:1278: *** please set COMPUTE_HEADER_DEPENDENCIES to yes, no, or auto (not "1"). Stop.
So now when someone using a compiler without -MMD support reports trouble building git, you can reproduce it by running "make COMPUTE_HEADER_DEPENDENCIES=no".
Suggested-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Improved-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> --- Junio C Hamano wrote:
> Eek. At least at the end user UI level, couldn't we do this as a tristate?
Nice idea. Here it is.
Makefile | 31 ++++++++++++++++++++++++------- 1 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/Makefile b/Makefile index 34ac7957..b1c80a67 100644 --- a/Makefile +++ b/Makefile @@ -250,6 +250,12 @@ all:: # DEFAULT_EDITOR='$GIT_FALLBACK_EDITOR', # DEFAULT_EDITOR='"C:\Program Files\Vim\gvim.exe" --nofork' # +# Define COMPUTE_HEADER_DEPENDENCIES to "yes" if you want dependencies on +# header files to be automatically computed, to avoid rebuilding objects when +# an unrelated header file changes. Define it to "no" to use the hard-coded +# dependency rules. The default is "auto", which means to use computed header +# dependencies if your compiler is detected to support it. +# # Define CHECK_HEADER_DEPENDENCIES to check for problems in the hard-coded # dependency rules. # @@ -1246,21 +1252,32 @@ endif endif ifdef CHECK_HEADER_DEPENDENCIES -COMPUTE_HEADER_DEPENDENCIES = +COMPUTE_HEADER_DEPENDENCIES = no USE_COMPUTED_HEADER_DEPENDENCIES = -else +endif + ifndef COMPUTE_HEADER_DEPENDENCIES +COMPUTE_HEADER_DEPENDENCIES = auto +endif + +ifeq ($(COMPUTE_HEADER_DEPENDENCIES),auto) dep_check = $(shell $(CC) $(ALL_CFLAGS) \ -c -MF /dev/null -MMD -MP -x c /dev/null -o /dev/null 2>&1; \ echo $$?) ifeq ($(dep_check),0) -COMPUTE_HEADER_DEPENDENCIES=YesPlease -endif +override COMPUTE_HEADER_DEPENDENCIES = yes +else +override COMPUTE_HEADER_DEPENDENCIES = no endif endif -ifdef COMPUTE_HEADER_DEPENDENCIES +ifeq ($(COMPUTE_HEADER_DEPENDENCIES),yes) USE_COMPUTED_HEADER_DEPENDENCIES = YesPlease +else +ifneq ($(COMPUTE_HEADER_DEPENDENCIES),no) +$(error please set COMPUTE_HEADER_DEPENDENCIES to yes, no, or auto \ +(not "$(COMPUTE_HEADER_DEPENDENCIES)")) +endif endif ifdef SANE_TOOL_PATH @@ -1907,7 +1924,7 @@ OBJECTS := $(GIT_OBJS) $(XDIFF_OBJS) $(VCSSVN_OBJS) dep_files := $(foreach f,$(OBJECTS),$(dir $f).depend/$(notdir $f).d) dep_dirs := $(addsuffix .depend,$(sort $(dir $(OBJECTS)))) -ifdef COMPUTE_HEADER_DEPENDENCIES +ifeq ($(COMPUTE_HEADER_DEPENDENCIES),yes) $(dep_dirs): @mkdir -p $@ @@ -1920,7 +1937,7 @@ Please unset CHECK_HEADER_DEPENDENCIES and try again) endif endif -ifndef COMPUTE_HEADER_DEPENDENCIES +ifneq ($(COMPUTE_HEADER_DEPENDENCIES),yes) ifndef CHECK_HEADER_DEPENDENCIES dep_dirs = missing_dep_dirs =
-- 1.7.8.rc2