Re: [OE-core][scarthgap 16/16] rust: Enable dynamic linking with llvm

["Yoann Congal" <yoann.congal@smile.fr>]

On Mon Mar 30, 2026 at 12:37 AM CEST, Yoann Congal wrote:
> From: Sunil Dora <sunilkumar.dora@windriver.com>
>
> Fixes [Yocto #16058]
>
> A segmentation fault occurs in rustc (e.g. in
> llvm::X86ReadAdvanceTable) when reusing sstate artifacts built with
> different host toolchain versions.
>
> Issue sequence:
> 1. llvm-native is built with a newer toolchain
>    (e.g. GCC 15/Binutils 2.45).
> 2. rust-native is later built with an older linker.
>    (e.g. GCC 12/Binutils 2.40).
> 3. The older linker statically links parts of llvm-native into
>    librustc_driver.
> 4. The resulting binary crashes at runtime inside the statically
>    linked LLVM code.
>
> The corruption happens at link time when mixing static native objects
> produced by different toolchain generations.
>
> Enable dynamic LLVM linking (link-shared = true) for rust-native so rustc
> links against libLLVM.so instead of static archives, avoiding host linker
> incompatibilities when reusing sstate artifacts.
>
> Signed-off-by: Sunil Dora <sunilkumar.dora@windriver.com>
> Suggested-by: Alexander Kanavin <alex@linutronix.de>
> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> (cherry picked from commit 74ba238ff1ba1e9b612aece1989b828f3a8f8770)
> Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
> ---

I did not wanted to send that patch, please ignore.

>  meta/recipes-devtools/rust/rust_1.75.0.bb | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/meta/recipes-devtools/rust/rust_1.75.0.bb b/meta/recipes-devtools/rust/rust_1.75.0.bb
> index b9348bf0507..f037bb33715 100644
> --- a/meta/recipes-devtools/rust/rust_1.75.0.bb
> +++ b/meta/recipes-devtools/rust/rust_1.75.0.bb
> @@ -128,6 +128,8 @@ python do_configure() {
>  
>      # [llvm]
>      config.add_section("llvm")
> +    if d.getVar('PN') == "rust-native":
> +        config.set("llvm", "link-shared", e(True))
>      config.set("llvm", "static-libstdcpp", e(False))
>      if "llvm" in (d.getVar('TC_CXX_RUNTIME') or ""):
>          config.set("llvm", "use-libcxx", e(True))


-- 
Yoann Congal
Smile ECS