Hi Paolo
On Wed, Jul 8, 2026 at 12:27 AM <[email protected]> wrote:
>
> From: Marc-André Lureau <[email protected]>
>
> bindgen < 0.72.1 linked against libclang >= 22 generates opaque structs
> for C types declared with "typedef struct X X;" forward declarations,
> common in QEMU. The struct fields are missing from the generated Rust
> bindings. For example, with bindgen 0.71.x and LLVM 22, a struct like:
>
> typedef struct VMStateField VMStateField;
> struct VMStateField {
> const char *name;
> int version_id;
> };
>
> produces:
>
> pub struct VMStateField {
> pub _address: u8,
> }
>
> instead of:
>
> pub struct VMStateField {
> pub name: *const c_char,
> pub version_id: c_int,
> }
>
> The build then fails with:
> error[E0609]: no field `version_id` on type `VMStateField`
> error[E0609]: no field `flags` on type `VMStateField`
> error[E0560]: struct `util_sys::Error` has no field named `msg`
>
> Check the bindgen version against llvm-config at configure time. With
> -Drust=enabled, error out; with -Drust=auto, disable Rust and suggest
> the upgrade.
>
> Signed-off-by: Marc-Andre Lureau <[email protected]>
iirc, you told me that the patch was good. Can you add a-b/r-b, should
I take it through my tree?
> ---
> meson.build | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/meson.build b/meson.build
> index 164328ded83..c965cef352e 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -125,6 +125,25 @@ if have_rust
> have_rust = false
> endif
> endif
> +
> + # bindgen < 0.72.1 generates opaque structs for "typedef struct X X;"
> + # patterns when linked against libclang >= 22.
> + if have_rust and bindgen.version().version_compare('<0.72.1')
> + llvm_config = find_program('llvm-config', required: false)
> + if llvm_config.found()
> + llvm_version = run_command(llvm_config, '--version',
> + check: true).stdout().strip()
> + if llvm_version.version_compare('>=22.0.0')
> + if get_option('rust').enabled()
> + error('bindgen ' + bindgen.version() + ' is incompatible with LLVM
> ' + llvm_version + '. ' +
> + 'Please upgrade with "cargo install --locked
> [email protected]"')
> + else
> + warning('bindgen ' + bindgen.version() + ' is incompatible with
> LLVM ' + llvm_version + ', disabling Rust.')
> + have_rust = false
> + endif
> + endif
> + endif
> + endif
> endif
>
> if have_rust
> --
> 2.55.0
>
>
