From 30a7729771731971839cc969d2a321e6ea7a144b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 23 Apr 2020 23:23:53 +0900 Subject: kbuild: use -MMD instead of -MD to exclude system headers from dependency This omits system headers from the generated header dependency. System headers are not updated unless you upgrade the compiler. Nor do they contain CONFIG options, so fixdep does not need to parse them. Having said that, the effect of this optimization will be quite small because the kernel code generally does not include system headers except . Host programs include a lot of system headers, but there are not so many in the kernel tree. At first, keeping system headers in .*.cmd files might be useful to detect the compiler update, but there is no guarantee that is included from every file. So, I implemented a more reliable way in the previous commit. Signed-off-by: Masahiro Yamada --- scripts/Kbuild.include | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts/Kbuild.include') diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 6cabf20ce66a..0c3dc983439b 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -16,7 +16,7 @@ pound := \# dot-target = $(dir $@).$(notdir $@) ### -# The temporary file to save gcc -MD generated dependencies must not +# The temporary file to save gcc -MMD generated dependencies must not # contain a comma depfile = $(subst $(comma),_,$(dot-target).d) -- cgit v1.2.3 From f2f02ebd8f3833626642688b2d2c6a7b3c141fa9 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 14 Jun 2020 23:43:40 +0900 Subject: kbuild: improve cc-option to clean up all temporary files When cc-option and friends evaluate compiler flags, the temporary file $$TMP is created as an output object, and automatically cleaned up. The actual file path of $$TMP is ..tmp, here is the process ID of $(shell ...) invoked from cc-option. (Please note $$$$ is the escape sequence of $$). Such garbage files are cleaned up in most cases, but some compiler flags create additional output files. For example, -gsplit-dwarf creates a .dwo file. When CONFIG_DEBUG_INFO_SPLIT=y, you will see a bunch of ..dwo files left in the top of build directories. You may not notice them unless you do 'ls -a', but the garbage files will increase every time you run 'make'. This commit changes the temporary object path to .tmp_/tmp, and removes .tmp_ directory when exiting. Separate build artifacts such as *.dwo will be cleaned up all together because their file paths are usually determined based on the base name of the object. Another example is -ftest-coverage, which outputs the coverage data into .gcno Signed-off-by: Masahiro Yamada --- scripts/Kbuild.include | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'scripts/Kbuild.include') diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 0c3dc983439b..9a15fbf66aa1 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -86,20 +86,21 @@ cc-cross-prefix = $(firstword $(foreach c, $(1), \ $(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c)))) # output directory for tests below -TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/) +TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$ # try-run # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise) # Exit code chooses option. "$$TMP" serves as a temporary file and is # automatically cleaned up. try-run = $(shell set -e; \ - TMP="$(TMPOUT).$$$$.tmp"; \ - TMPO="$(TMPOUT).$$$$.o"; \ + TMP=$(TMPOUT)/tmp; \ + TMPO=$(TMPOUT)/tmp.o; \ + mkdir -p $(TMPOUT); \ + trap "rm -rf $(TMPOUT)" EXIT; \ if ($(1)) >/dev/null 2>&1; \ then echo "$(2)"; \ else echo "$(3)"; \ - fi; \ - rm -f "$$TMP" "$$TMPO") + fi) # as-option # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) -- cgit v1.2.3 From 132305b3b474a85152302ceda4551384cce3904e Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 2 Aug 2020 00:00:50 +0900 Subject: kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base Commit d26e94149276 ("kbuild: no gcc-plugins during cc-option tests") was neeeded because scripts/Makefile.gcc-plugins was too early. This is unneeded by including scripts/Makefile.gcc-plugins last, and being careful to not add cc-option tests after it. Signed-off-by: Masahiro Yamada --- scripts/Kbuild.include | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) (limited to 'scripts/Kbuild.include') diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 9a15fbf66aa1..83a1637417e5 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -119,25 +119,21 @@ as-instr = $(call try-run,\ __cc-option = $(call try-run,\ $(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4)) -# Do not attempt to build with gcc plugins during cc-option tests. -# (And this uses delayed resolution so the flags will be up to date.) -CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) - # cc-option # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) cc-option = $(call __cc-option, $(CC),\ - $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2)) + $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS),$(1),$(2)) # cc-option-yn # Usage: flag := $(call cc-option-yn,-march=winchip-c6) cc-option-yn = $(call try-run,\ - $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n) + $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n) # cc-disable-warning # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable) cc-disable-warning = $(call try-run,\ - $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) + $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) # cc-ifversion # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) -- cgit v1.2.3