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authorAndrea Righi <andrea.righi@canonical.com>2023-02-10 22:51:41 +0100
committerMiguel Ojeda <ojeda@kernel.org>2023-04-19 19:34:43 +0200
commitd966c3cab924fb750fefef11e77a6fa07dd5420e (patch)
treedfa6a30c407a1a5729579615b05d7a0b8284d3ab /rust/Makefile
parentccc4505454db10402d5284f22d8b7db62e636fc5 (diff)
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>
Diffstat (limited to 'rust/Makefile')
-rw-r--r--rust/Makefile14
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