Messages in this thread | | | Date | Fri, 10 Feb 2023 22:37:45 +0100 | From | Andrea Righi <> | Subject | Re: [PATCH] rust: allow to use INIT_STACK_ALL_ZERO |
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On Fri, Feb 10, 2023 at 10:39:27AM -0700, Nathan Chancellor wrote: > On Fri, Feb 10, 2023 at 06:22:03PM +0100, Andrea Righi wrote: > > With CONFIG_INIT_STACK_ALL_ZERO enabled, bindgen is passing > > -ftrivial-auto-var-init=zero to clang, that triggers the following: > > > > error: '-ftrivial-auto-var-init=zero' hasn't been enabled; enable it at your own peril for benchmarking purpose only with '-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang' > > > > This flag should be dropped in clang-17, but at the moment it seems more > > reasonable to add it to the bindgen CFLAGS to prevent the error above. > > > > In this way we can enable CONFIG_INIT_STACK_ALL_ZERO with CONFIG_RUST > > without triggering any build error. > > > > Link: https://reviews.llvm.org/D125142 > > Signed-off-by: Andrea Righi <andrea.righi@canonical.com> > > If this went via the kbuild tree, would we be able to use > $(CC_AUTO_VAR_INIT_ZERO_ENABLER)? > > https://git.kernel.org/masahiroy/linux-kbuild/c/4e3feaad6ff8a7a57e3bf3308a93c93e3a2e17a6 > > Although, I suppose this could be a problem if the version of clang > being used to build the kernel does not support this flag while the > version of libclang in bindgen requires it?
I didn't have much success with CC_AUTO_VAR_INIT_ZERO_ENABLER, but maybe a better way is to check if the version of libclang used by bindgen is less than 17, considering that is extra clang option is supposed to be dropped in clang-17:
https://github.com/llvm/llvm-project/issues/44842
I'll send a v2, unless we find a better way to support this auto var zero-init feature.
-Andrea
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