bindgen produces an E0588 error when dealing with a packed struct with union.

[apanda]

Input C/C++ Header

struct rte_memseg {
    uint64_t phys_addr;      /**< Start physical address. */
    RTE_STD_C11
    union {
        void *addr;         /**< Start virtual address. */
        uint64_t addr_64;   /**< Makes sure addr is always 64 bits */
    };
    size_t len;               /**< Length of the segment. */
    uint64_t hugepage_sz;       /**< The pagesize of underlying memory */
    int32_t socket_id;          /**< NUMA socket ID. */
    uint32_t nchannel;          /**< Number of channels. */
    uint32_t nrank;             /**< Number of ranks. */
} __attribute__((__packed__));

Bindgen Invocation

    let bindings = bindgen::Builder::default()
        .header(header_path.to_str().unwrap())
        .rust_target(bindgen::RustTarget::Nightly)
        .generate()
        .expect("Unable to generate DPDK bindings");

Actual Results

// Insert the (incorrect/buggy) generated bindings here
error[E0588]: packed type cannot transitively contain a `[repr(align)]` type
    --> /home/apanda/NetBricks/target/release/build/e2d2-02e086d04d42e68f/out/dpdk_bindings.rs:8890:1
     |
8890 | / pub struct rte_memseg {
8891 | |     #[doc = "< Start physical address."]
8892 | |     pub phys_addr: phys_addr_t,
8893 | |     pub __bindgen_anon_1: rte_memseg__bindgen_ty_1,
...    |
8903 | |     pub nrank: u32,
8904 | | }
     | |_^

Expected Results

No Rust error.

[emilio]

I'm not sure how to really deal with this if rustc doesn't :(

Do you know if the C compiler ignores the aligned attribute or something?

[emilio]

Ah, this is slightly different, we shouldn't need #[repr(align)] in that case.

[emilio]

emilio@23d9229 has a fix.

[apanda]

Ah, excellent. Thank you 👍

[Jashwanth537]

Hey, i run into a similar issue, what is the fix, should i go about replacing .cargo\registry\src\index.crates.io-6f17d22bba15001f\bindgen-0.66.1\codegen\mod.rs ? as given above @emilio