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Commit 910b4046 authored by Sam Ravnborg's avatar Sam Ravnborg
Browse files

kbuild: introduce cc-cross-prefix 



cc-cross-prefix is useful for the architecture that like
to provide a default CROSS_COMPILE value,
but may have several to select between.

Sample usage:

ifneq ($(SUBARCH),$(ARCH))
        ifeq ($(CROSS_COMPILE),)
               CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
        endif
endif

Actual usage by the different archs will taken care of later.

Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
parent 50a8ec31

Documentation/kbuild/makefiles.txt

+22 −0
Original line number Diff line number Diff line
@@ -518,6 +518,28 @@ more details, with real examples. 
	In this example for a specific GCC version the build will error out explaining

	to the user why it stops.



    cc-cross-prefix

	cc-cross-prefix is used to check if there exist a $(CC) in path with

	one of the listed prefixes. The first prefix where there exist a

	prefix$(CC) in the PATH is returned - and if no prefix$(CC) is found

	then nothing is returned.

	Additional prefixes are separated by a single space in the

	call of cc-cross-prefix.

	This functionality is usefull for architecture Makefile that try

	to set CROSS_COMPILE to well know values but may have several

	values to select between.

	It is recommended only to try to set CROSS_COMPILE is it is a cross

	build (host arch is different from target arch). And is CROSS_COMPILE

	is already set then leave it with the old value.



	Example:

		#arch/m68k/Makefile

		ifneq ($(SUBARCH),$(ARCH))

		        ifeq ($(CROSS_COMPILE),)

		               CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu-)

			endif

		endif



=== 4 Host Program support



Kbuild supports building executables on the host for use during the

scripts/Kbuild.include

+11 −0
Original line number Diff line number Diff line
@@ -56,6 +56,17 @@ endef 
# gcc support functions

# See documentation in Documentation/kbuild/makefiles.txt



# cc-cross-prefix

# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)

# Return first prefix where a prefix$(CC) is found in PATH.

# If no $(CC) found in PATH with listed prefixes return nothing

cc-cross-prefix =  \

	$(word 1, $(foreach c,$(1),                                   \

		$(shell set -e;                                       \

		if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \

			echo $(c);                                    \

		fi)))



# output directory for tests below

TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)