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| author |   Nick Desaulniers <ndesaulniers@google.com> | 2021-08-02 11:39:09 -0700 |
|---|---|---|
| committer |   Masahiro Yamada <masahiroy@kernel.org> | 2021-08-10 09:13:25 +0900 |
| commit | 231ad7f409f16b9f9505f69e058dff488a7e6bde (patch) | |
| tree | 4c6a28e7e2bf185937f79a85dce93f19996bf461 /scripts | |
| parent | Makefile: move initial clang flag handling into scripts/Makefile.clang (diff) | |
| download | linux-dev-231ad7f409f16b9f9505f69e058dff488a7e6bde.tar.xz linux-dev-231ad7f409f16b9f9505f69e058dff488a7e6bde.zip | |
Makefile: infer --target from ARCH for CC=clang
We get constant feedback that the command line invocation of make is too
long when compiling with LLVM. CROSS_COMPILE is helpful when a toolchain
has a prefix of the target triple, or is an absolute path outside of
$PATH.
Since a Clang binary is generally multi-targeted, we can infer a given
target from SRCARCH/ARCH. If CROSS_COMPILE is not set, simply set
--target= for CLANG_FLAGS, KBUILD_CFLAGS, and KBUILD_AFLAGS based on
$SRCARCH.
Previously, we'd cross compile via:
$ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make LLVM=1 LLVM_IAS=1
Now:
$ ARCH=arm64 make LLVM=1 LLVM_IAS=1
For native builds (not involving cross compilation) we now explicitly
specify a target triple rather than rely on the implicit host triple.
Link: https://github.com/ClangBuiltLinux/linux/issues/1399
Suggested-by: Arnd Bergmann <arnd@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Arnd Bergmann <arnd@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/Makefile.clang | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 297932e973d4..1f4e3eb70f88 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -1,6 +1,27 @@ -ifneq ($(CROSS_COMPILE),) +# Individual arch/{arch}/Makefiles should use -EL/-EB to set intended +# endianness and -m32/-m64 to set word size based on Kconfigs instead of +# relying on the target triple. +CLANG_TARGET_FLAGS_arm := arm-linux-gnueabi +CLANG_TARGET_FLAGS_arm64 := aarch64-linux-gnu +CLANG_TARGET_FLAGS_hexagon := hexagon-linux-musl +CLANG_TARGET_FLAGS_m68k := m68k-linux-gnu +CLANG_TARGET_FLAGS_mips := mipsel-linux-gnu +CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu +CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu +CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu +CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu +CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH)) + +ifeq ($(CROSS_COMPILE),) +ifeq ($(CLANG_TARGET_FLAGS),) +$(error Specify CROSS_COMPILE or add '--target=' option to scripts/Makefile.clang) +else +CLANG_FLAGS += --target=$(CLANG_TARGET_FLAGS) +endif # CLANG_TARGET_FLAGS +else CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) -endif +endif # CROSS_COMPILE + ifeq ($(LLVM_IAS),1) CLANG_FLAGS += -integrated-as else |