codegen: Fix some sloppiness in our handling of opaque types.

Fixes #801

Author: emilio

src/codegen/mod.rs

@@ -1571,7 +1571,8 @@ impl CodeGenerator for CompInfo {
         }
 
         // Yeah, sorry about that.
-        if item.is_opaque(ctx, &()) {
+        let is_opaque = item.is_opaque(ctx, &());
+        if is_opaque {
             fields.clear();
             methods.clear();
 
@@ -1613,7 +1614,14 @@ impl CodeGenerator for CompInfo {
         // NOTE: This check is conveniently here to avoid the dummy fields we
         // may add for unused template parameters.
         if self.is_unsized(ctx) {
-            let has_address = layout.map_or(true, |l| l.size != 0);
+            let has_address = if is_opaque {
+                // Generate the address field if it's an opaque type and
+                // couldn't determine the layout of the blob.
+                layout.is_none()
+            } else {
+                layout.map_or(true, |l| l.size != 0)
+            };
+
             if has_address {
                 let ty = BlobTyBuilder::new(Layout::new(1, 1)).build();
                 let field = StructFieldBuilder::named("_address")
@@ -1670,9 +1678,11 @@ impl CodeGenerator for CompInfo {
         }
 
         if used_template_params.is_none() {
-            for var in self.inner_vars() {
-                ctx.resolve_item(*var)
-                    .codegen(ctx, result, whitelisted_items, &());
+            if !is_opaque {
+                for var in self.inner_vars() {
+                    ctx.resolve_item(*var)
+                        .codegen(ctx, result, whitelisted_items, &());
+                }
             }
 
             if ctx.options().layout_tests {
@@ -1707,8 +1717,8 @@ impl CodeGenerator for CompInfo {
                         })
                         .count() > 1;
 
-                    let should_skip_field_offset_checks = item.is_opaque(ctx, &()) ||
-                                                          too_many_base_vtables;
+                    let should_skip_field_offset_checks =
+                        is_opaque || too_many_base_vtables;
 
                     let check_field_offset = if should_skip_field_offset_checks {
                         None

tests/expectations/tests/issue-801-opaque-sloppiness.rs

@@ -0,0 +1,40 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+
+#[repr(C)]
+#[derive(Debug, Default, Copy)]
+pub struct B {
+    pub _bindgen_opaque_blob: u8,
+}
+#[test]
+fn bindgen_test_layout_B() {
+    assert_eq!(::std::mem::size_of::<B>() , 1usize , concat ! (
+               "Size of: " , stringify ! ( B ) ));
+    assert_eq! (::std::mem::align_of::<B>() , 1usize , concat ! (
+                "Alignment of " , stringify ! ( B ) ));
+}
+impl Clone for B {
+    fn clone(&self) -> Self { *self }
+}
+#[repr(C)]
+#[derive(Debug, Default, Copy)]
+pub struct C {
+    pub b: B,
+}
+#[test]
+fn bindgen_test_layout_C() {
+    assert_eq!(::std::mem::size_of::<C>() , 1usize , concat ! (
+               "Size of: " , stringify ! ( C ) ));
+    assert_eq! (::std::mem::align_of::<C>() , 1usize , concat ! (
+                "Alignment of " , stringify ! ( C ) ));
+    assert_eq! (unsafe { & ( * ( 0 as * const C ) ) . b as * const _ as usize
+                } , 0usize , concat ! (
+                "Alignment of field: " , stringify ! ( C ) , "::" , stringify
+                ! ( b ) ));
+}
+impl Clone for C {
+    fn clone(&self) -> Self { *self }
+}

tests/headers/issue-801-opaque-sloppiness.hpp

@@ -0,0 +1,11 @@
+// bindgen-flags: --opaque-type "B" --whitelist-type "C"
+
+class A;
+
+class B {
+  static A a;
+};
+
+class C {
+  B b;
+};