codegen: Support repr(align)

Cargo.toml

@@ -13,7 +13,7 @@ name = "bindgen"
 readme = "README.md"
 repository = "https://github.com/rust-lang-nursery/rust-bindgen"
 documentation = "https://docs.rs/bindgen"
-version = "0.33.2"
+version = "0.34.0"
 build = "build.rs"
 
 include = [

src/codegen/impl_partialeq.rs

@@ -20,7 +20,7 @@ pub fn gen_partialeq_impl(
             &self._bindgen_opaque_blob[..] == &other._bindgen_opaque_blob[..]
         });
     } else if comp_info.kind() == CompKind::Union {
-        assert!(!ctx.options().rust_features().untagged_union());
+        assert!(!ctx.options().rust_features().untagged_union);
         tokens.push(quote! {
             &self.bindgen_union_field[..] == &other.bindgen_union_field[..]
         });

src/codegen/mod.rs

@@ -1527,13 +1527,16 @@ impl CodeGenerator for CompInfo {
             });
         }
 
+        let mut explicit_align = None;
         if is_opaque {
             // Opaque item should not have generated methods, fields.
             debug_assert!(fields.is_empty());
             debug_assert!(methods.is_empty());
 
             match layout {
                 Some(l) => {
+                    explicit_align = Some(l.align);
+
                     let ty = helpers::blob(l);
                     fields.push(quote! {
                         pub _bindgen_opaque_blob: #ty ,
@@ -1555,6 +1558,7 @@ impl CodeGenerator for CompInfo {
                     if layout.align == 1 {
                         packed = true;
                     } else {
+                        explicit_align = Some(layout.align);
                         let ty = helpers::blob(Layout::new(0, layout.align));
                         fields.push(quote! {
                             pub __bindgen_align: #ty ,
@@ -1637,6 +1641,18 @@ impl CodeGenerator for CompInfo {
             attributes.push(attributes::repr("C"));
         }
 
+        if ctx.options().rust_features().repr_align {
+            if let Some(explicit) = explicit_align {
+                // Ensure that the struct has the correct alignment even in
+                // presence of alignas.
+                let explicit = helpers::ast_ty::int_expr(explicit as i64);
+                attributes.push(quote! {
+                    #[repr(align(#explicit))]
+                });
+            }
+        }
+
+
         let mut derives = vec![];
         if item.can_derive_debug(ctx) {
             derives.push("Debug");
@@ -1655,7 +1671,7 @@ impl CodeGenerator for CompInfo {
         if item.can_derive_copy(ctx) && !item.annotations().disallow_copy() {
             derives.push("Copy");
 
-            if ctx.options().rust_features().builtin_clone_impls() ||
+            if ctx.options().rust_features().builtin_clone_impls ||
                 used_template_params.is_some()
             {
                 // FIXME: This requires extra logic if you have a big array in a
@@ -1996,7 +2012,7 @@ impl MethodCodegen for Method {
             _ => panic!("How in the world?"),
         };
 
-        if let (Abi::ThisCall, false) = (signature.abi(), ctx.options().rust_features().thiscall_abi()) {
+        if let (Abi::ThisCall, false) = (signature.abi(), ctx.options().rust_features().thiscall_abi) {
             return;
         }
 
@@ -3167,7 +3183,7 @@ impl TryToRustTy for FunctionSig {
         let abi = self.abi();
 
         match abi {
-            Abi::ThisCall if !ctx.options().rust_features().thiscall_abi() => {
+            Abi::ThisCall if !ctx.options().rust_features().thiscall_abi => {
                 warn!("Skipping function with thiscall ABI that isn't supported by the configured Rust target");
                 Ok(quote::Tokens::new())
             }
@@ -3264,7 +3280,7 @@ impl CodeGenerator for Function {
         }
 
         let abi = match signature.abi() {
-            Abi::ThisCall if !ctx.options().rust_features().thiscall_abi() => {
+            Abi::ThisCall if !ctx.options().rust_features().thiscall_abi => {
                 warn!("Skipping function with thiscall ABI that isn't supported by the configured Rust target");
                 return;
             }

src/features.rs

@@ -92,6 +92,8 @@ macro_rules! rust_target_base {
             => Stable_1_19 => 1.19;
             /// Rust stable 1.21
             => Stable_1_21 => 1.21;
+            /// Rust stable 1.25
+            => Stable_1_25 => 1.25;
             /// Nightly rust
             => Nightly => nightly;
         );
@@ -111,7 +113,10 @@ macro_rules! rust_feature_def {
         #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
         pub struct RustFeatures {
             $(
-                $feature: bool,
+                $(
+                    #[$attr]
+                )*
+                pub $feature: bool,
             )*
         }
 
@@ -124,15 +129,6 @@ macro_rules! rust_feature_def {
                     )*
                 }
             }
-
-            $(
-                $(
-                    #[$attr]
-                )*
-                pub fn $feature(&self) -> bool {
-                    self.$feature
-                }
-            )*
         }
     }
 }
@@ -144,6 +140,8 @@ rust_feature_def!(
     => thiscall_abi;
     /// builtin impls for `Clone` ([PR](https://github.com/rust-lang/rust/pull/43690))
     => builtin_clone_impls;
+    /// repr(align) https://github.com/rust-lang/rust/pull/47006
+    => repr_align;
 );
 
 impl From<RustTarget> for RustFeatures {
@@ -158,6 +156,10 @@ impl From<RustTarget> for RustFeatures {
             features.builtin_clone_impls = true;
         }
 
+        if rust_target >= RustTarget::Stable_1_25 {
+            features.repr_align = true;
+        }
+
         if rust_target >= RustTarget::Nightly {
             features.thiscall_abi = true;
         }
@@ -189,6 +191,7 @@ mod test {
         test_target("1.0", RustTarget::Stable_1_0);
         test_target("1.19", RustTarget::Stable_1_19);
         test_target("1.21", RustTarget::Stable_1_21);
+        test_target("1.25", RustTarget::Stable_1_25);
         test_target("nightly", RustTarget::Nightly);
     }
 }

src/ir/analysis/derive_copy.rs

@@ -234,7 +234,7 @@ impl<'ctx> MonotoneFramework for CannotDeriveCopy<'ctx> {
                 }
 
                 if info.kind() == CompKind::Union {
-                    if !self.ctx.options().rust_features().untagged_union() {
+                    if !self.ctx.options().rust_features().untagged_union {
                         // NOTE: If there's no template parameters we can derive
                         // copy unconditionally, since arrays are magical for
                         // rustc, and __BindgenUnionField always implements

src/ir/analysis/derive_debug.rs

@@ -150,7 +150,7 @@ impl<'ctx> MonotoneFramework for CannotDeriveDebug<'ctx> {
             });
             return if layout_can_derive &&
                       !(ty.is_union() &&
-                        self.ctx.options().rust_features().untagged_union()) {
+                        self.ctx.options().rust_features().untagged_union) {
                 trace!("    we can trivially derive Debug for the layout");
                 ConstrainResult::Same
             } else {
@@ -235,7 +235,7 @@ impl<'ctx> MonotoneFramework for CannotDeriveDebug<'ctx> {
                 );
 
                 if info.kind() == CompKind::Union {
-                    if self.ctx.options().rust_features().untagged_union() {
+                    if self.ctx.options().rust_features().untagged_union {
                         trace!("    cannot derive Debug for Rust unions");
                         return self.insert(id);
                     }

src/ir/analysis/derive_default.rs

@@ -177,7 +177,7 @@ impl<'ctx> MonotoneFramework for CannotDeriveDefault<'ctx> {
             });
             return if layout_can_derive &&
                       !(ty.is_union() &&
-                        self.ctx.options().rust_features().untagged_union()) {
+                        self.ctx.options().rust_features().untagged_union) {
                 trace!("    we can trivially derive Default for the layout");
                 ConstrainResult::Same
             } else {
@@ -271,7 +271,7 @@ impl<'ctx> MonotoneFramework for CannotDeriveDefault<'ctx> {
                 }
 
                 if info.kind() == CompKind::Union {
-                    if self.ctx.options().rust_features().untagged_union() {
+                    if self.ctx.options().rust_features().untagged_union {
                         trace!("    cannot derive Default for Rust unions");
                         return self.insert(id);
                     }

src/ir/analysis/derive_hash.rs

@@ -137,7 +137,7 @@ impl<'ctx> MonotoneFramework for CannotDeriveHash<'ctx> {
             });
             return if layout_can_derive &&
                 !(ty.is_union() &&
-                  self.ctx.options().rust_features().untagged_union()) {
+                  self.ctx.options().rust_features().untagged_union) {
                 trace!("    we can trivially derive Hash for the layout");
                 ConstrainResult::Same
             } else {
@@ -257,7 +257,7 @@ impl<'ctx> MonotoneFramework for CannotDeriveHash<'ctx> {
                 }
 
                 if info.kind() == CompKind::Union {
-                    if self.ctx.options().rust_features().untagged_union() {
+                    if self.ctx.options().rust_features().untagged_union {
                         trace!("    cannot derive Hash for Rust unions");
                         return self.insert(id);
                     }

src/ir/analysis/derive_partialeq_or_partialord.rs

@@ -119,7 +119,7 @@ impl<'ctx> CannotDerivePartialEqOrPartialOrd<'ctx> {
         trace!("ty: {:?}", ty);
         if item.is_opaque(self.ctx, &()) {
             if ty.is_union()
-                && self.ctx.options().rust_features().untagged_union()
+                && self.ctx.options().rust_features().untagged_union
             {
                 trace!(
                     "    cannot derive `PartialEq`/`PartialOrd` for Rust unions"
@@ -242,7 +242,7 @@ impl<'ctx> CannotDerivePartialEqOrPartialOrd<'ctx> {
                 }
 
                 if info.kind() == CompKind::Union {
-                    if self.ctx.options().rust_features().untagged_union() {
+                    if self.ctx.options().rust_features().untagged_union {
                         trace!(
                             "    cannot derive `PartialEq`/`PartialOrd` for Rust unions"
                         );

src/ir/comp.rs

@@ -1543,7 +1543,7 @@ impl CompInfo {
     ///     1. Current RustTarget allows for `untagged_union`
     ///     2. Each field can derive `Copy`
     pub fn can_be_rust_union(&self, ctx: &BindgenContext) -> bool {
-        if !ctx.options().rust_features().untagged_union() {
+        if !ctx.options().rust_features().untagged_union {
             return false;
         }
 

src/lib.rs

@@ -600,6 +600,12 @@ impl Builder {
         self
     }
 
+    /// Disable support for native Rust unions, if supported.
+    pub fn disable_untagged_union(mut self) -> Self {
+        self.options.rust_features.untagged_union = false;
+        self
+    }
+
     /// Set the output graphviz file.
     pub fn emit_ir_graphviz<T: Into<String>>(mut self, path: T) -> Builder {
         let path = path.into();

tests/expectations/tests/repr-align.rs

@@ -0,0 +1,67 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+#![cfg(feature = "nightly")]
+
+#[repr(C)]
+#[repr(align(8))]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct a {
+    pub b: ::std::os::raw::c_int,
+    pub c: ::std::os::raw::c_int,
+    pub __bindgen_align: [u64; 0usize],
+}
+#[test]
+fn bindgen_test_layout_a() {
+    assert_eq!(
+        ::std::mem::size_of::<a>(),
+        8usize,
+        concat!("Size of: ", stringify!(a))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<a>(),
+        8usize,
+        concat!("Alignment of ", stringify!(a))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<a>())).b as *const _ as usize },
+        0usize,
+        concat!("Offset of field: ", stringify!(a), "::", stringify!(b))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<a>())).c as *const _ as usize },
+        4usize,
+        concat!("Offset of field: ", stringify!(a), "::", stringify!(c))
+    );
+}
+#[repr(C)]
+#[repr(align(8))]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct b {
+    pub b: ::std::os::raw::c_int,
+    pub c: ::std::os::raw::c_int,
+    pub __bindgen_align: [u64; 0usize],
+}
+#[test]
+fn bindgen_test_layout_b() {
+    assert_eq!(
+        ::std::mem::size_of::<b>(),
+        8usize,
+        concat!("Size of: ", stringify!(b))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<b>(),
+        8usize,
+        concat!("Alignment of ", stringify!(b))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<b>())).b as *const _ as usize },
+        0usize,
+        concat!("Offset of field: ", stringify!(b), "::", stringify!(b))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<b>())).c as *const _ as usize },
+        4usize,
+        concat!("Offset of field: ", stringify!(b), "::", stringify!(c))
+    );
+}

tests/headers/repr-align.hpp

@@ -0,0 +1,11 @@
+// bindgen-flags: --raw-line '#![cfg(feature = "nightly")]' --rust-target 1.25 -- -std=c++11
+
+struct alignas(8) a {
+  int b;
+  int c;
+};
+
+struct alignas(double) b {
+  int b;
+  int c;
+};