We get constant feedback that the command line invocation of make is too
long. CROSS_COMPILE is helpful when a toolchain has a prefix of the
target triple, or is an absolute path outside of $PATH, but it's mostly
redundant for a given ARCH.
Instead, let's infer it from SRCARCH, and move some flag handling into a
new file included from the top level Makefile.
Changes v2 -> v3:
* Remove requirement that LLVM=1 be set. Instead, if building with just
CC=clang LLVM_IAS=1 instead of LLVM=1 LLVM_IAS=1, you should use
LD=ld.lld explicitly, or LD=aarch64-linux-gnu-ld. (As per Masahiro)
Example:
$ ARCH=arm64 make CC=clang LLVM_IAS=1 LD=ld.lld OBJCOPY=llvm-objcopy \
STRIP=llvm-strip -j72 defconfig all
(It's still preferable to use LLVM=1 IMO, but this is maximally
flexible.)
* Change oneliner from LLVM=1 to CC=clang.
* Update Docs slightly.
Changes v1 -> v2:
* patch 1/2 untouched.
* Fix typos in commit message as per Geert and Masahiro.
* Use SRCARCH instead of ARCH, simplifying x86 handling, as per
Masahiro. Add his sugguested by tag.
* change commit oneline from 'drop' to 'infer.'
* Add detail about explicit host --target and relationship of ARCH to
SRCARCH, as per Masahiro.
Nick Desaulniers (2):
Makefile: move initial clang flag handling into scripts/Makefile.clang
Makefile: infer CROSS_COMPILE from SRCARCH for CC=clang LLVM_IAS=1
Documentation/kbuild/llvm.rst | 6 +++++
MAINTAINERS | 1 +
Makefile | 15 +------------
scripts/Makefile.clang | 42 +++++++++++++++++++++++++++++++++++
4 files changed, 50 insertions(+), 14 deletions(-)
create mode 100644 scripts/Makefile.clang
base-commit: 27932b6a2088eac7a5afa5471963b926cfbb4de7
--
2.32.0.432.gabb21c7263-goog
