[PATCH] kbuild: terminate Kconfig when $(CC) or $(LD) is missing

From: Masahiro Yamada
Date: Thu May 09 2019 - 03:37:39 EST


If the compiler specified by $(CC) is not present, the Kconfig stage
sprinkles 'not found' messages, then succeeds.

$ make CROSS_COMPILE=foo defconfig
/bin/sh: 1: foogcc: not found
/bin/sh: 1: foogcc: not found
*** Default configuration is based on 'x86_64_defconfig'
./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found
./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found
./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found
./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found
./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found
./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found
./scripts/clang-version.sh: 11: ./scripts/clang-version.sh: foogcc: not found
./scripts/gcc-plugin.sh: 11: ./scripts/gcc-plugin.sh: foogcc: not found
init/Kconfig:16:warning: 'GCC_VERSION': number is invalid
#
# configuration written to .config
#

Terminate parsing files immediately if $(CC) or $(LD) is not found.
"make *config" will fail more nicely.

$ make CROSS_COMPILE=foo defconfig
*** Default configuration is based on 'x86_64_defconfig'
scripts/Kconfig.include:34: compiler 'foogcc' not found
make[1]: *** [scripts/kconfig/Makefile;82: defconfig] Error 1
make: *** [Makefile;557: defconfig] Error 2

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

Makefile | 2 +-
scripts/Kconfig.include | 8 ++++++++
2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 28965187c528..bd7ae11947cb 100644
--- a/Makefile
+++ b/Makefile
@@ -537,7 +537,7 @@ endif
# Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
# and from include/config/auto.conf.cmd to detect the compiler upgrade.
-CC_VERSION_TEXT = $(shell $(CC) --version | head -n 1)
+CC_VERSION_TEXT = $(shell $(CC) --version 2>/dev/null | head -n 1)

ifeq ($(config-targets),1)
# ===========================================================================
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index 87ff1dcc6bd5..0b267fb27f07 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -18,6 +18,10 @@ if-success = $(shell,{ $(1); } >/dev/null 2>&1 && echo "$(2)" || echo "$(3)")
# Return y if <command> exits with 0, n otherwise
success = $(if-success,$(1),y,n)

+# $(failure,<command>)
+# Return n if <command> exits with 0, y otherwise
+failure = $(if-success,$(1),n,y)
+
# $(cc-option,<flag>)
# Return y if the compiler supports <flag>, n otherwise
cc-option = $(success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null)
@@ -26,5 +30,9 @@ cc-option = $(success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null)
# Return y if the linker supports <flag>, n otherwise
ld-option = $(success,$(LD) -v $(1))

+# check if $(CC) and $(LD) exist
+$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
+$(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
+
# gcc version including patch level
gcc-version := $(shell,$(srctree)/scripts/gcc-version.sh $(CC))
--
2.17.1