Auto merge of #1066 - pepyakin:bitfields-in-unions, r=fitzgen

Bitfields in unions

Fixes #744

I think it is WIP for the moment as I didn't run tests locally.

6 files changed, 467 insertions, 2 deletions

diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index ea9fec41..94a62b97 100644
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -1152,7 +1152,21 @@ impl<'a> FieldCodegen<'a> for BitfieldUnit {
         F: Extend<quote::Tokens>,
         M: Extend<quote::Tokens>,
     {
-        let field_ty = helpers::blob(self.layout());
+        let field_ty = if parent.is_union() && !parent.can_be_rust_union(ctx) {
+            let ty = helpers::blob(self.layout());
+            if ctx.options().enable_cxx_namespaces {
+                quote! {
+                    root::__BindgenUnionField<#ty>
+                }
+            } else {
+                quote! {
+                    __BindgenUnionField<#ty>
+                }
+            }
+        } else {
+            helpers::blob(self.layout())
+        };
+        
         let unit_field_name = format!("_bitfield_{}", self.nth());
         let unit_field_ident = ctx.rust_ident(&unit_field_name);
 
diff --git a/src/ir/comp.rs b/src/ir/comp.rs
index 230ba5b4..7320015f 100644
--- a/src/ir/comp.rs
+++ b/src/ir/comp.rs
@@ -1498,7 +1498,7 @@ impl CompInfo {
                 Field::DataMember(ref field_data) => {
                     field_data.ty().can_derive_copy(ctx)
                 }
-                Field::Bitfields(_) => false,
+                Field::Bitfields(_) => true,
             })
     }
 }
diff --git a/tests/expectations/tests/union_bitfield.rs b/tests/expectations/tests/union_bitfield.rs
new file mode 100644
index 00000000..c67557ef
--- /dev/null
+++ b/tests/expectations/tests/union_bitfield.rs
@@ -0,0 +1,185 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+
+#[repr(C)]
+#[derive(Copy)]
+pub union U4 {
+    pub _bitfield_1: u8,
+    _bindgen_union_align: u32,
+}
+#[test]
+fn bindgen_test_layout_U4() {
+    assert_eq!(
+        ::std::mem::size_of::<U4>(),
+        4usize,
+        concat!("Size of: ", stringify!(U4))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<U4>(),
+        4usize,
+        concat!("Alignment of ", stringify!(U4))
+    );
+}
+impl Clone for U4 {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl Default for U4 {
+    fn default() -> Self {
+        unsafe { ::std::mem::zeroed() }
+    }
+}
+impl U4 {
+    #[inline]
+    pub fn derp(&self) -> ::std::os::raw::c_uint {
+        let mut unit_field_val: u8 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u8 as *mut u8,
+                ::std::mem::size_of::<u8>(),
+            )
+        };
+        let mask = 1u64 as u8;
+        let val = (unit_field_val & mask) >> 0usize;
+        unsafe { ::std::mem::transmute(val as u32) }
+    }
+    #[inline]
+    pub fn set_derp(&mut self, val: ::std::os::raw::c_uint) {
+        let mask = 1u64 as u8;
+        let val = val as u32 as u8;
+        let mut unit_field_val: u8 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u8 as *mut u8,
+                ::std::mem::size_of::<u8>(),
+            )
+        };
+        unit_field_val &= !mask;
+        unit_field_val |= (val << 0usize) & mask;
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &unit_field_val as *const _ as *const u8,
+                &mut self._bitfield_1 as *mut _ as *mut u8,
+                ::std::mem::size_of::<u8>(),
+            );
+        }
+    }
+    #[inline]
+    pub fn new_bitfield_1(derp: ::std::os::raw::c_uint) -> u8 {
+        (0 | ((derp as u32 as u8) << 0usize) & (1u64 as u8))
+    }
+}
+#[repr(C)]
+#[derive(Copy)]
+pub union B {
+    pub _bitfield_1: u32,
+    _bindgen_union_align: u32,
+}
+#[test]
+fn bindgen_test_layout_B() {
+    assert_eq!(
+        ::std::mem::size_of::<B>(),
+        4usize,
+        concat!("Size of: ", stringify!(B))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<B>(),
+        4usize,
+        concat!("Alignment of ", stringify!(B))
+    );
+}
+impl Clone for B {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl Default for B {
+    fn default() -> Self {
+        unsafe { ::std::mem::zeroed() }
+    }
+}
+impl B {
+    #[inline]
+    pub fn foo(&self) -> ::std::os::raw::c_uint {
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        let mask = 2147483647u64 as u32;
+        let val = (unit_field_val & mask) >> 0usize;
+        unsafe { ::std::mem::transmute(val as u32) }
+    }
+    #[inline]
+    pub fn set_foo(&mut self, val: ::std::os::raw::c_uint) {
+        let mask = 2147483647u64 as u32;
+        let val = val as u32 as u32;
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        unit_field_val &= !mask;
+        unit_field_val |= (val << 0usize) & mask;
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &unit_field_val as *const _ as *const u8,
+                &mut self._bitfield_1 as *mut _ as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            );
+        }
+    }
+    #[inline]
+    pub fn bar(&self) -> ::std::os::raw::c_uchar {
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        let mask = 2147483648u64 as u32;
+        let val = (unit_field_val & mask) >> 31usize;
+        unsafe { ::std::mem::transmute(val as u8) }
+    }
+    #[inline]
+    pub fn set_bar(&mut self, val: ::std::os::raw::c_uchar) {
+        let mask = 2147483648u64 as u32;
+        let val = val as u8 as u32;
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        unit_field_val &= !mask;
+        unit_field_val |= (val << 31usize) & mask;
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &unit_field_val as *const _ as *const u8,
+                &mut self._bitfield_1 as *mut _ as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            );
+        }
+    }
+    #[inline]
+    pub fn new_bitfield_1(foo: ::std::os::raw::c_uint, bar: ::std::os::raw::c_uchar) -> u32 {
+        ((0 | ((foo as u32 as u32) << 0usize) & (2147483647u64 as u32))
+            | ((bar as u8 as u32) << 31usize) & (2147483648u64 as u32))
+    }
+}
diff --git a/tests/expectations/tests/union_bitfield_1_0.rs b/tests/expectations/tests/union_bitfield_1_0.rs
new file mode 100644
index 00000000..d8fe660c
--- /dev/null
+++ b/tests/expectations/tests/union_bitfield_1_0.rs
@@ -0,0 +1,242 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+
+#[repr(C)]
+pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
+impl<T> __BindgenUnionField<T> {
+    #[inline]
+    pub fn new() -> Self {
+        __BindgenUnionField(::std::marker::PhantomData)
+    }
+    #[inline]
+    pub unsafe fn as_ref(&self) -> &T {
+        ::std::mem::transmute(self)
+    }
+    #[inline]
+    pub unsafe fn as_mut(&mut self) -> &mut T {
+        ::std::mem::transmute(self)
+    }
+}
+impl<T> ::std::default::Default for __BindgenUnionField<T> {
+    #[inline]
+    fn default() -> Self {
+        Self::new()
+    }
+}
+impl<T> ::std::clone::Clone for __BindgenUnionField<T> {
+    #[inline]
+    fn clone(&self) -> Self {
+        Self::new()
+    }
+}
+impl<T> ::std::marker::Copy for __BindgenUnionField<T> {}
+impl<T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
+impl<T> ::std::hash::Hash for __BindgenUnionField<T> {
+    fn hash<H: ::std::hash::Hasher>(&self, _state: &mut H) {}
+}
+impl<T> ::std::cmp::PartialEq for __BindgenUnionField<T> {
+    fn eq(&self, _other: &__BindgenUnionField<T>) -> bool {
+        true
+    }
+}
+impl<T> ::std::cmp::Eq for __BindgenUnionField<T> {}
+#[repr(C)]
+#[derive(Debug, Default, Copy, Hash, PartialEq, Eq)]
+pub struct U4 {
+    pub _bitfield_1: __BindgenUnionField<u8>,
+    pub bindgen_union_field: u32,
+}
+#[test]
+fn bindgen_test_layout_U4() {
+    assert_eq!(
+        ::std::mem::size_of::<U4>(),
+        4usize,
+        concat!("Size of: ", stringify!(U4))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<U4>(),
+        4usize,
+        concat!("Alignment of ", stringify!(U4))
+    );
+}
+impl Clone for U4 {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl U4 {
+    #[inline]
+    pub fn derp(&self) -> ::std::os::raw::c_uint {
+        let mut unit_field_val: u8 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u8 as *mut u8,
+                ::std::mem::size_of::<u8>(),
+            )
+        };
+        let mask = 1u64 as u8;
+        let val = (unit_field_val & mask) >> 0usize;
+        unsafe { ::std::mem::transmute(val as u32) }
+    }
+    #[inline]
+    pub fn set_derp(&mut self, val: ::std::os::raw::c_uint) {
+        let mask = 1u64 as u8;
+        let val = val as u32 as u8;
+        let mut unit_field_val: u8 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u8 as *mut u8,
+                ::std::mem::size_of::<u8>(),
+            )
+        };
+        unit_field_val &= !mask;
+        unit_field_val |= (val << 0usize) & mask;
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &unit_field_val as *const _ as *const u8,
+                &mut self._bitfield_1 as *mut _ as *mut u8,
+                ::std::mem::size_of::<u8>(),
+            );
+        }
+    }
+    #[inline]
+    pub fn new_bitfield_1(derp: ::std::os::raw::c_uint) -> u8 {
+        (0 | ((derp as u32 as u8) << 0usize) & (1u64 as u8))
+    }
+}
+#[repr(C)]
+#[derive(Debug, Default, Copy, Hash, PartialEq, Eq)]
+pub struct B {
+    pub _bitfield_1: __BindgenUnionField<u32>,
+    pub bindgen_union_field: u32,
+}
+#[test]
+fn bindgen_test_layout_B() {
+    assert_eq!(
+        ::std::mem::size_of::<B>(),
+        4usize,
+        concat!("Size of: ", stringify!(B))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<B>(),
+        4usize,
+        concat!("Alignment of ", stringify!(B))
+    );
+}
+impl Clone for B {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl B {
+    #[inline]
+    pub fn foo(&self) -> ::std::os::raw::c_uint {
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        let mask = 2147483647u64 as u32;
+        let val = (unit_field_val & mask) >> 0usize;
+        unsafe { ::std::mem::transmute(val as u32) }
+    }
+    #[inline]
+    pub fn set_foo(&mut self, val: ::std::os::raw::c_uint) {
+        let mask = 2147483647u64 as u32;
+        let val = val as u32 as u32;
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        unit_field_val &= !mask;
+        unit_field_val |= (val << 0usize) & mask;
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &unit_field_val as *const _ as *const u8,
+                &mut self._bitfield_1 as *mut _ as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            );
+        }
+    }
+    #[inline]
+    pub fn bar(&self) -> ::std::os::raw::c_uchar {
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        let mask = 2147483648u64 as u32;
+        let val = (unit_field_val & mask) >> 31usize;
+        unsafe { ::std::mem::transmute(val as u8) }
+    }
+    #[inline]
+    pub fn set_bar(&mut self, val: ::std::os::raw::c_uchar) {
+        let mask = 2147483648u64 as u32;
+        let val = val as u8 as u32;
+        let mut unit_field_val: u32 = unsafe { ::std::mem::uninitialized() };
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &self._bitfield_1 as *const _ as *const u8,
+                &mut unit_field_val as *mut u32 as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            )
+        };
+        unit_field_val &= !mask;
+        unit_field_val |= (val << 31usize) & mask;
+        unsafe {
+            ::std::ptr::copy_nonoverlapping(
+                &unit_field_val as *const _ as *const u8,
+                &mut self._bitfield_1 as *mut _ as *mut u8,
+                ::std::mem::size_of::<u32>(),
+            );
+        }
+    }
+    #[inline]
+    pub fn new_bitfield_1(foo: ::std::os::raw::c_uint, bar: ::std::os::raw::c_uchar) -> u32 {
+        ((0 | ((foo as u32 as u32) << 0usize) & (2147483647u64 as u32))
+            | ((bar as u8 as u32) << 31usize) & (2147483648u64 as u32))
+    }
+}
+#[repr(C)]
+#[derive(Copy)]
+pub struct HasBigBitfield {
+    pub _bitfield_1: __BindgenUnionField<[u8; 16usize]>,
+    pub bindgen_union_field: [u8; 16usize],
+}
+#[test]
+fn bindgen_test_layout_HasBigBitfield() {
+    assert_eq!(
+        ::std::mem::size_of::<HasBigBitfield>(),
+        16usize,
+        concat!("Size of: ", stringify!(HasBigBitfield))
+    );
+}
+impl Clone for HasBigBitfield {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl Default for HasBigBitfield {
+    fn default() -> Self {
+        unsafe { ::std::mem::zeroed() }
+    }
+}
diff --git a/tests/headers/union_bitfield.h b/tests/headers/union_bitfield.h
new file mode 100644
index 00000000..99072957
--- /dev/null
+++ b/tests/headers/union_bitfield.h
@@ -0,0 +1,10 @@
+// bindgen-flags: --with-derive-hash --with-derive-partialeq --with-derive-eq --impl-partialeq
+
+union U4 {
+    unsigned derp : 1;
+};
+
+union B {
+    unsigned foo : 31;
+    unsigned char bar : 1;
+};
diff --git a/tests/headers/union_bitfield_1_0.h b/tests/headers/union_bitfield_1_0.h
new file mode 100644
index 00000000..06b61ad7
--- /dev/null
+++ b/tests/headers/union_bitfield_1_0.h
@@ -0,0 +1,14 @@
+// bindgen-flags: --rust-target 1.0 --with-derive-hash --with-derive-partialeq --with-derive-eq --impl-partialeq
+
+union U4 {
+    unsigned derp : 1;
+};
+
+union B {
+    unsigned foo : 31;
+    unsigned char bar : 1;
+};
+
+union HasBigBitfield {
+    __int128 x : 128;
+};