Bindgen knows the size of the C struct but doesn't know the fields.

[Ddystopia]

Hello, for some reason a small amount of structs are just not getting generated correctly. Bindgen somehow knows the correct size of the struct (I verified by hand, size is indeed 52 bytes and align is 4). But when it comes to actually generating the fields it a) doesn't generate fields, b) doesn't generate assertions for those fields, c) leaves _address: u8 sentinel. And the most perplexing thing is that structs that are defined near by are getting generated fine.

This is not an issue because I can't get it to reproduce. When I clone it as a local repository anywhere on my machine, it doesn't work, but when I clone it on other machines, it generates code fine... Rust versions match if I am not mistaken, Cargo.lock file is commited and is the same.

This is a potential issue with rust-bindgen (like, in any case, how does it know the size of the struct but doesn't know any of the fields?). Does anyone have any ideas what it may be?

I am getting code generated like this:

#[repr(C)]
#[derive(Debug, Default, Copy, Clone)]
pub struct TX_MUTEX_STRUCT {
    pub _address: u8,
}
#[allow(clippy::unnecessary_operation, clippy::identity_op)]
const _: () = {
    ["Size of TX_MUTEX_STRUCT"][::core::mem::size_of::<TX_MUTEX_STRUCT>() - 52usize];
    ["Alignment of TX_MUTEX_STRUCT"][::core::mem::align_of::<TX_MUTEX_STRUCT>() - 4usize];
};
pub type TX_MUTEX = TX_MUTEX_STRUCT;

The struct itself is:

typedef struct TX_MUTEX_STRUCT
{

    /* Define the mutex ID used for error checking.  */
    ULONG               tx_mutex_id;

    /* Define the mutex's name.  */
    CHAR                *tx_mutex_name;

    /* Define the mutex ownership count.  */
    UINT                tx_mutex_ownership_count;

    /* Define the mutex ownership pointer.  This pointer points to the
       the thread that owns the mutex.  */
    TX_THREAD           *tx_mutex_owner;

    /* Define the priority inheritance flag.  If this flag is set, priority
       inheritance will be in effect.  */
    UINT                tx_mutex_inherit;

    /* Define the save area for the owning thread's original priority.  */
    UINT                tx_mutex_original_priority;

    /* Define the mutex suspension list head along with a count of
       how many threads are suspended.  */
    struct TX_THREAD_STRUCT
                        *tx_mutex_suspension_list;
    UINT                tx_mutex_suspended_count;

    /* Define the created list next and previous pointers.  */
    struct TX_MUTEX_STRUCT
                        *tx_mutex_created_next,
                        *tx_mutex_created_previous;

    /* Define the priority of the highest priority thread waiting for
       this mutex.  */
    UINT                tx_mutex_highest_priority_waiting;

    /* Define the owned list next and previous pointers.  */
    struct TX_MUTEX_STRUCT
                        *tx_mutex_owned_next,
                        *tx_mutex_owned_previous;

#ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO

    /* Define the number of mutex puts.  */
    ULONG               tx_mutex_performance_put_count;

    /* Define the total number of mutex gets.  */
    ULONG               tx_mutex_performance_get_count;

    /* Define the total number of mutex suspensions.  */
    ULONG               tx_mutex_performance_suspension_count;

    /* Define the total number of mutex timeouts.  */
    ULONG               tx_mutex_performance_timeout_count;

    /* Define the total number of priority inversions.  */
    ULONG               tx_mutex_performance_priority_inversion_count;

    /* Define the total number of priority inheritance conditions.  */
    ULONG               tx_mutex_performance__priority_inheritance_count;
#endif

    /* Define the port extension in the mutex control block. This
       is typically defined to whitespace in tx_port.h.  */
    TX_MUTEX_EXTENSION

} TX_MUTEX;

Header file in question: https://github.com/eclipse-threadx/threadx/blob/master/common/inc/tx_api.h

[Ddystopia]

I reproduced!! The problem is in libclang 22.1.3 , when I tried with version 19 it works fine.

[emilio]

I think #3264 is related? Try master / latest release?

[Ddystopia]

Yes, it is fixed. Thank you.