Linux Makefile try-run

1. try-run

scripts/Kbuild.include

try-run = $(shell set -e; TMP="$(TMPOUT).$$$$.tmp"; TMPO="$(TMPOUT).$$$$.O"; if ($(1)) >/dev/null 2>&1; then echo "$(2)"; else echo "$(3)"; fi; rm -f "$$TMP" "$$TMPO")

2. cc-option

scripts/Kbuild.include

cc-option = $(call try-run, $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP", $(1), $(2))

cc-option在顶层makefile的示例

KBUILD_CFLAGS += $(call cc-option, --param=allow-store-data-races=0)

3. cc-disable-warning

scripts/Kbuild.include

cc-disable-warning = $(call try-run, $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP" -Wno-$(strip $(1)))

cc-disable-warning在顶层makefile的示例

KBUILD_FLAGS += -Os $(call cc-disable-warning, maybe-uninitialized, )