diff options
| -rw-r--r-- | Documentation/kbuild/makefiles.txt | 22 | ||||
| -rw-r--r-- | scripts/Kbuild.include | 11 |
2 files changed, 33 insertions, 0 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index f099b814d383..6166e2d7da76 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -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 diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index de7bb284c611..b96ea8d6a5ed 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -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))/) |