Fix incomplete array alignment in struct

Author: zzhu

src/codegen/mod.rs

@@ -3658,17 +3658,23 @@ mod utils {
         let incomplete_array_decl = quote! {
             #[repr(C)]
             #[derive(Default)]
-            pub struct __IncompleteArrayField<T>(
-                ::#prefix::marker::PhantomData<T>);
+            pub struct __IncompleteArrayField<T>{
+                _alignment: [*const (); 0],
+                _marker: ::#prefix::marker::PhantomData<T>,
+            }
         };
 
         let incomplete_array_impl = quote! {
             impl<T> __IncompleteArrayField<T> {
                 #[inline]
                 pub fn new() -> Self {
-                    __IncompleteArrayField(::#prefix::marker::PhantomData)
+                    __IncompleteArrayField {
+                        _marker: ::#prefix::marker::PhantomData,
+                        _alignment: Default::default(),
+                    }
                 }
 
+
                 #[inline]
                 pub unsafe fn as_ptr(&self) -> *const T {
                     ::#prefix::mem::transmute(self)

tests/expectations/tests/struct_with_incomplete_array.rs

@@ -0,0 +1,80 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+#[repr(C)]
+#[derive(Default)]
+pub struct __IncompleteArrayField<T> {
+    _alignment: [*const (); 0],
+    _marker: ::std::marker::PhantomData<T>,
+}
+impl<T> __IncompleteArrayField<T> {
+    #[inline]
+    pub fn new() -> Self {
+        __IncompleteArrayField {
+            _marker: ::std::marker::PhantomData,
+            _alignment: Default::default(),
+        }
+    }
+    #[inline]
+    pub unsafe fn as_ptr(&self) -> *const T {
+        ::std::mem::transmute(self)
+    }
+    #[inline]
+    pub unsafe fn as_mut_ptr(&mut self) -> *mut T {
+        ::std::mem::transmute(self)
+    }
+    #[inline]
+    pub unsafe fn as_slice(&self, len: usize) -> &[T] {
+        ::std::slice::from_raw_parts(self.as_ptr(), len)
+    }
+    #[inline]
+    pub unsafe fn as_mut_slice(&mut self, len: usize) -> &mut [T] {
+        ::std::slice::from_raw_parts_mut(self.as_mut_ptr(), len)
+    }
+}
+impl<T> ::std::fmt::Debug for __IncompleteArrayField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__IncompleteArrayField")
+    }
+}
+impl<T> ::std::clone::Clone for __IncompleteArrayField<T> {
+    #[inline]
+    fn clone(&self) -> Self {
+        Self::new()
+    }
+}
+impl<T> ::std::marker::Copy for __IncompleteArrayField<T> {}
+#[repr(C)]
+#[derive(Debug, Default)]
+pub struct bpf_raw_tracepoint_args {
+    pub args: __IncompleteArrayField<::std::os::raw::c_ulonglong>,
+}
+#[test]
+fn bindgen_test_layout_bpf_raw_tracepoint_args() {
+    assert_eq!(
+        ::std::mem::size_of::<bpf_raw_tracepoint_args>(),
+        0usize,
+        concat!("Size of: ", stringify!(bpf_raw_tracepoint_args))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<bpf_raw_tracepoint_args>(),
+        8usize,
+        concat!("Alignment of ", stringify!(bpf_raw_tracepoint_args))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<bpf_raw_tracepoint_args>())).args as *const _ as usize },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(bpf_raw_tracepoint_args),
+            "::",
+            stringify!(args)
+        )
+    );
+}

tests/headers/struct_with_incomplete_array.hpp

@@ -0,0 +1,3 @@
+struct bpf_raw_tracepoint_args {                                                                                              
+        unsigned long long args[0];                                                                                                        
+};