[PATCH 5.4 02/21] tools: Allow proper CC/CXX/... override with LLVM=1 in Makefile.include

Greg Kroah-Hartman
2021-07-29T13:57:41Z

From: Yonghong Song <yhs@fb.com>

commit f62700ce63a315b4607cc9e97aa15ea409a677b9 upstream.

selftests/bpf/Makefile includes tools/scripts/Makefile.include.
With the following command
make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1 V=1
some files are still compiled with gcc. This patch
fixed the case if CC/AR/LD/CXX/STRIP is allowed to be
overridden, it will be written to clang/llvm-ar/..., instead of
gcc binaries. The definition of CC_NO_CLANG is also relocated
to the place after the above CC is defined.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210413153419.3028165-1-yhs@fb.com
Cc: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/scripts/Makefile.include | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -39,8 +39,6 @@ EXTRA_WARNINGS += -Wundef
EXTRA_WARNINGS += -Wwrite-strings
EXTRA_WARNINGS += -Wformat

-CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
-
# Makefiles suck: This macro sets a default value of $(2) for the
# variable named by $(1), unless the variable has been set by
# environment or command line. This is necessary for CC and AR
@@ -52,12 +50,22 @@ define allow-override
$(eval $(1) = $(2)))
endef

+ifneq ($(LLVM),)
+$(call allow-override,CC,clang)
+$(call allow-override,AR,llvm-ar)
+$(call allow-override,LD,ld.lld)
+$(call allow-override,CXX,clang++)
+$(call allow-override,STRIP,llvm-strip)
+else
# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
$(call allow-override,CC,$(CROSS_COMPILE)gcc)
$(call allow-override,AR,$(CROSS_COMPILE)ar)
$(call allow-override,LD,$(CROSS_COMPILE)ld)
$(call allow-override,CXX,$(CROSS_COMPILE)g++)
$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
+endif
+
+CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)

ifneq ($(LLVM),)
HOSTAR ?= llvm-ar