Auto merge of #282 - impowski:layout_template_specializations, r=emilio

First steps to fix issue #57

This should generate tests for fully specialized templates.
TODO:
- [x] Tests

r? @emilio

Author: bors-servo

libbindgen/src/codegen/mod.rs

@@ -670,10 +670,32 @@ impl CodeGenerator for CompInfo {
 
         // Don't output classes with template parameters that aren't types, and
         // also don't output template specializations, neither total or partial.
-        //
-        // TODO: Generate layout tests for template specializations, yay!
-        if self.has_non_type_template_params() ||
-           self.is_template_specialization() {
+        if self.has_non_type_template_params() {
+            return;
+        }
+
+        if self.is_template_specialization() {
+            let layout = item.kind().expect_type().layout(ctx);
+
+            if let Some(layout) = layout {
+                let fn_name = format!("__bindgen_test_layout_template_{}", item.id().as_usize());
+                let fn_name = ctx.rust_ident_raw(&fn_name);
+                let ident = item.to_rust_ty(ctx);
+                let prefix = ctx.trait_prefix();
+                let size_of_expr = quote_expr!(ctx.ext_cx(),
+                                               ::$prefix::mem::size_of::<$ident>());
+                let align_of_expr = quote_expr!(ctx.ext_cx(),
+                                                ::$prefix::mem::align_of::<$ident>());
+                let size = layout.size;
+                let align = layout.align;
+                let item = quote_item!(ctx.ext_cx(),
+                                       #[test]
+                                       fn $fn_name() {
+                                           assert_eq!($size_of_expr, $size);
+                                           assert_eq!($align_of_expr, $align);
+                                       }).unwrap();
+                result.push(item);
+            }
             return;
         }
 

libbindgen/tests/expectations/tests/anon_union.rs

@@ -75,3 +75,10 @@ fn bindgen_test_layout_ErrorResult() {
 impl Clone for ErrorResult {
     fn clone(&self) -> Self { *self }
 }
+#[test]
+fn __bindgen_test_layout_template_17() {
+    assert_eq!(::std::mem::size_of::<TErrorResult<::std::os::raw::c_int>>() ,
+               24usize);
+    assert_eq!(::std::mem::align_of::<TErrorResult<::std::os::raw::c_int>>() ,
+               8usize);
+}

libbindgen/tests/expectations/tests/class_with_dtor.rs

@@ -20,3 +20,10 @@ fn bindgen_test_layout_WithoutDtor() {
     assert_eq!(::std::mem::size_of::<WithoutDtor>() , 8usize);
     assert_eq!(::std::mem::align_of::<WithoutDtor>() , 8usize);
 }
+#[test]
+fn __bindgen_test_layout_template_11() {
+    assert_eq!(::std::mem::size_of::<HandleWithDtor<::std::os::raw::c_int>>()
+               , 8usize);
+    assert_eq!(::std::mem::align_of::<HandleWithDtor<::std::os::raw::c_int>>()
+               , 8usize);
+}

libbindgen/tests/expectations/tests/crtp.rs

@@ -23,6 +23,11 @@ fn bindgen_test_layout_Derived() {
 impl Clone for Derived {
     fn clone(&self) -> Self { *self }
 }
+#[test]
+fn __bindgen_test_layout_template_5() {
+    assert_eq!(::std::mem::size_of::<Base<Derived>>() , 1usize);
+    assert_eq!(::std::mem::align_of::<Base<Derived>>() , 1usize);
+}
 #[repr(C)]
 #[derive(Debug)]
 pub struct BaseWithDestructor<T> {
@@ -41,3 +46,10 @@ fn bindgen_test_layout_DerivedFromBaseWithDestructor() {
     assert_eq!(::std::mem::align_of::<DerivedFromBaseWithDestructor>() ,
                1usize);
 }
+#[test]
+fn __bindgen_test_layout_template_12() {
+    assert_eq!(::std::mem::size_of::<BaseWithDestructor<DerivedFromBaseWithDestructor>>()
+               , 1usize);
+    assert_eq!(::std::mem::align_of::<BaseWithDestructor<DerivedFromBaseWithDestructor>>()
+               , 1usize);
+}

libbindgen/tests/expectations/tests/template.rs

@@ -12,6 +12,13 @@ pub struct Foo<T, U> {
     pub m_member_arr: [T; 1usize],
     pub _phantom_1: ::std::marker::PhantomData<U>,
 }
+#[test]
+fn __bindgen_test_layout_template_10() {
+    assert_eq!(::std::mem::size_of::<Foo<::std::os::raw::c_int, ::std::os::raw::c_int>>()
+               , 24usize);
+    assert_eq!(::std::mem::align_of::<Foo<::std::os::raw::c_int, ::std::os::raw::c_int>>()
+               , 8usize);
+}
 extern "C" {
     #[link_name = "_Z3bar3FooIiiE"]
     pub fn bar(foo: Foo<::std::os::raw::c_int, ::std::os::raw::c_int>);
@@ -168,3 +175,10 @@ pub struct TemplateWithVar<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+#[test]
+fn __bindgen_test_layout_template_132() {
+    assert_eq!(::std::mem::size_of::<WithDtor<::std::os::raw::c_int>>() ,
+               4usize);
+    assert_eq!(::std::mem::align_of::<WithDtor<::std::os::raw::c_int>>() ,
+               4usize);
+}