From 6768fa4bcb6c1618248f135d04b9287ba2724ae0 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 11 Dec 2022 11:54:47 +0900 Subject: kbuild: add read-file macro Since GNU Make 4.2, $(file ...) supports the read operater '<', which is useful to read a file without forking a new process. No warning is shown even if the input file is missing. For older Make versions, it falls back to the cat command. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Reviewed-by: Alexander Lobakin Tested-by: Alexander Lobakin --- scripts/Kbuild.include | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'scripts/Kbuild.include') diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 3be7c2d75667..21e76ba0de17 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -10,6 +10,10 @@ empty := space := $(empty) $(empty) space_escape := _-_SPACE_-_ pound := \# +define newline + + +endef ### # Comparison macros. @@ -61,6 +65,16 @@ stringify = $(squote)$(quote)$1$(quote)$(squote) kbuild-dir = $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) kbuild-file = $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile) +### +# Read a file, replacing newlines with spaces +# +# Make 4.2 or later can read a file by using its builtin function. +ifneq ($(filter-out 3.% 4.0 4.1, $(MAKE_VERSION)),) +read-file = $(subst $(newline),$(space),$(file < $1)) +else +read-file = $(shell cat $1 2>/dev/null) +endif + ### # Easy method for doing a status message kecho := : -- cgit v1.2.3