diff options
| author | Andrea Righi <andrea.righi@canonical.com> | 2023-02-10 22:51:41 +0100 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2023-04-19 19:34:43 +0200 |
| commit | d966c3cab924fb750fefef11e77a6fa07dd5420e (patch) | |
| tree | dfa6a30c407a1a5729579615b05d7a0b8284d3ab | |
| parent | ccc4505454db10402d5284f22d8b7db62e636fc5 (diff) | |
| download | lwn-d966c3cab924fb750fefef11e77a6fa07dd5420e.tar.gz lwn-d966c3cab924fb750fefef11e77a6fa07dd5420e.zip | |
rust: allow to use INIT_STACK_ALL_ZERO
With CONFIG_INIT_STACK_ALL_ZERO enabled, bindgen passes
-ftrivial-auto-var-init=zero to clang, that triggers the following
error:
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'
However, this additional option that is currently required by clang is
deprecated since clang-16 and going to be removed in the future,
likely with clang-18.
So, make sure bindgen is using this extra option if the major version of
the libclang used by bindgen is < 16.
In this way we can enable CONFIG_INIT_STACK_ALL_ZERO with CONFIG_RUST
without triggering any build error.
Link: https://github.com/llvm/llvm-project/issues/44842
Link: https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0-rc2/clang/docs/ReleaseNotes.rst#deprecated-compiler-flags
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[Changed to < 16, added link and reworded]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
| -rw-r--r-- | rust/Makefile | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/rust/Makefile b/rust/Makefile index 41ac8401a8be..aef85e9e8eeb 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -262,6 +262,20 @@ BINDGEN_TARGET := $(BINDGEN_TARGET_$(SRCARCH)) # some configurations, with new GCC versions, etc. bindgen_extra_c_flags = -w --target=$(BINDGEN_TARGET) +# Auto variable zero-initialization requires an additional special option with +# clang that is going to be removed sometime in the future (likely in +# clang-18), so make sure to pass this option only if clang supports it +# (libclang major version < 16). +# +# https://github.com/llvm/llvm-project/issues/44842 +# https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0-rc2/clang/docs/ReleaseNotes.rst#deprecated-compiler-flags +ifdef CONFIG_INIT_STACK_ALL_ZERO +libclang_maj_ver=$(shell $(BINDGEN) $(srctree)/scripts/rust_is_available_bindgen_libclang.h 2>&1 | sed -ne 's/.*clang version \([0-9]*\).*/\1/p') +ifeq ($(shell expr $(libclang_maj_ver) \< 16), 1) +bindgen_extra_c_flags += -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang +endif +endif + bindgen_c_flags = $(filter-out $(bindgen_skip_c_flags), $(c_flags)) \ $(bindgen_extra_c_flags) endif |