On Mon, Aug 24, 2026 at 4:34 PM Marc-André Lureau
<[email protected]> wrote:
>
> 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?
ping
>
> > ---
> > 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
> >
> >
