On 17 September 2024 15:29:50 GMT+02:00, Gary Guo gary@garyguo.net wrote:
On Tue, 17 Sep 2024 10:35:12 +0100 Conor Dooley conor@kernel.org wrote:
On 17 September 2024 01:08:48 IST, Jason Montleon jmontleo@redhat.com wrote:
Clang does not support '-mno-riscv-attribute' resulting in the error error: unknown argument: '-mno-riscv-attribute'
This appears to conflict with your subject, which cities gcc, but I suspect that's due to poor wording of the body of the commit message than a mistake in the subject. I'd rather disable rust on riscv when building with gcc, I've never been satisfied with the interaction between gcc and rustc's libclang w.r.t. extensions.
Cheers, Conor.
Hi Conor,
What happens is that when building against GCC, Kbuild gathers flag assuming CC is GCC, but bindgen uses clang instead. In this case, the CC is GCC and all C code is built by GCC. We have a filtering mechanism to only give bindgen (libclang) flags that it can understand.
Yes, but unfortunately I already knew how it worked. It's not flags I am worried about, it is extensions. Even using a libclang that doesn't match clang could be a problem, but we can at least declare that unsupported. Not digging it out on an airport bus, but we discussed the lack of GCC support on the original patch adding riscv, and decided against it.
While I do think this is a bit fragile, this is what I think all distros that enable Rust use. They still prefer to build C code with GCC. So I hope we can still keep that option around.
Best, Gary
Not setting BINDGEN_TARGET_riscv results in the in the error error: unsupported argument 'medany' to option '-mcmodel=' for target \ 'unknown' error: unknown target triple 'unknown'
Signed-off-by: Jason Montleon jmontleo@redhat.com Cc: stable@vger.kernel.org
rust/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/rust/Makefile b/rust/Makefile index f168d2c98a15..73eceaaae61e 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -228,11 +228,12 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \ -fzero-call-used-regs=% -fno-stack-clash-protection \ -fno-inline-functions-called-once -fsanitize=bounds-strict \ -fstrict-flex-arrays=% -fmin-function-alignment=% \
- --param=% --param asan-%
- --param=% --param asan-% -mno-riscv-attribute
# Derived from `scripts/Makefile.clang`. BINDGEN_TARGET_x86 := x86_64-linux-gnu BINDGEN_TARGET_arm64 := aarch64-linux-gnu +BINDGEN_TARGET_riscv := riscv64-linux-gnu BINDGEN_TARGET := $(BINDGEN_TARGET_$(SRCARCH))
# All warnings are inhibited since GCC builds are very experimental,
base-commit: ad060dbbcfcfcba624ef1a75e1d71365a98b86d8