Don't generate symbols for pure virtual functions.

Fixes rust-lang#1197.

Author: emilio

bindgen-integration/cpp/Test.h

@@ -15,6 +15,10 @@ class Test {
   static const int* countdown();
 };
 
+class ITest {
+  virtual void foo() = 0;
+};
+
 namespace testing {
 
 typedef Test TypeAlias;

src/clang.rs

@@ -606,11 +606,16 @@ impl Cursor {
         unsafe { clang_CXXMethod_isConst(self.x) != 0 }
     }
 
-    /// Is this cursor's referent a member function that is declared `const`?
+    /// Is this cursor's referent a member function that is virtual?
     pub fn method_is_virtual(&self) -> bool {
         unsafe { clang_CXXMethod_isVirtual(self.x) != 0 }
     }
 
+    /// Is this cursor's referent a member function that is pure virtual?
+    pub fn method_is_pure_virtual(&self) -> bool {
+        unsafe { clang_CXXMethod_isPureVirtual(self.x) != 0 }
+    }
+
     /// Is this cursor's referent a struct or class with virtual members?
     pub fn is_virtual_base(&self) -> bool {
         unsafe { clang_isVirtualBase(self.x) != 0 }

src/codegen/mod.rs

@@ -26,7 +26,7 @@ use ir::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault,
                  CanDerivePartialEq, CanDeriveEq, CanDerive};
 use ir::dot;
 use ir::enum_ty::{Enum, EnumVariant, EnumVariantValue};
-use ir::function::{Abi, Function, FunctionSig, Linkage};
+use ir::function::{Abi, Function, FunctionKind, FunctionSig, Linkage};
 use ir::int::IntKind;
 use ir::item::{IsOpaque, Item, ItemCanonicalName, ItemCanonicalPath};
 use ir::item_kind::ItemKind;
@@ -1878,13 +1878,8 @@ impl CodeGenerator for CompInfo {
             }
 
             if ctx.options().codegen_config.destructors {
-                if let Some((is_virtual, destructor)) = self.destructor() {
-                    let kind = if is_virtual {
-                        MethodKind::VirtualDestructor
-                    } else {
-                        MethodKind::Destructor
-                    };
-
+                if let Some((kind, destructor)) = self.destructor() {
+                    debug_assert!(kind.is_destructor());
                     Method::new(kind, destructor, false).codegen_method(
                         ctx,
                         &mut methods,
@@ -1990,9 +1985,9 @@ impl MethodCodegen for Method {
             match self.kind() {
                 MethodKind::Constructor => cc.constructors,
                 MethodKind::Destructor => cc.destructors,
-                MethodKind::VirtualDestructor => cc.destructors,
+                MethodKind::VirtualDestructor { .. } => cc.destructors,
                 MethodKind::Static | MethodKind::Normal |
-                MethodKind::Virtual => cc.methods,
+                MethodKind::Virtual { .. } => cc.methods,
             }
         });
 
@@ -3174,6 +3169,15 @@ impl CodeGenerator for Function {
             Linkage::External => {}
         }
 
+        // Pure virtual methods have no actual symbol, so we can't generate
+        // something meaningful for them.
+        match self.kind() {
+            FunctionKind::Method(ref method_kind) if method_kind.is_pure_virtual() => {
+                return;
+            }
+            _ => {},
+        }
+
         // Similar to static member variables in a class template, we can't
         // generate bindings to template functions, because the set of
         // instantiations is open ended and we have no way of knowing which

src/ir/comp.rs

@@ -37,13 +37,40 @@ pub enum MethodKind {
     /// A destructor.
     Destructor,
     /// A virtual destructor.
-    VirtualDestructor,
+    VirtualDestructor {
+        /// Whether it's pure virtual.
+        pure_virtual: bool,
+    },
     /// A static method.
     Static,
     /// A normal method.
     Normal,
     /// A virtual method.
-    Virtual,
+    Virtual {
+        /// Whether it's pure virtual.
+        pure_virtual: bool,
+    },
+}
+
+
+impl MethodKind {
+    /// Is this a destructor method?
+    pub fn is_destructor(&self) -> bool {
+        match *self {
+            MethodKind::Destructor |
+            MethodKind::VirtualDestructor { .. } => true,
+            _ => false,
+        }
+    }
+
+    /// Is this a pure virtual method?
+    pub fn is_pure_virtual(&self) -> bool {
+        match *self {
+            MethodKind::Virtual { pure_virtual } |
+            MethodKind::VirtualDestructor { pure_virtual } => pure_virtual,
+            _ => false,
+        }
+    }
 }
 
 /// A struct representing a C++ method, either static, normal, or virtual.
@@ -73,21 +100,18 @@ impl Method {
         self.kind
     }
 
-    /// Is this a destructor method?
-    pub fn is_destructor(&self) -> bool {
-        self.kind == MethodKind::Destructor ||
-            self.kind == MethodKind::VirtualDestructor
-    }
-
     /// Is this a constructor?
     pub fn is_constructor(&self) -> bool {
         self.kind == MethodKind::Constructor
     }
 
     /// Is this a virtual method?
     pub fn is_virtual(&self) -> bool {
-        self.kind == MethodKind::Virtual ||
-            self.kind == MethodKind::VirtualDestructor
+        match self.kind {
+            MethodKind::Virtual { .. } |
+            MethodKind::VirtualDestructor { .. } => true,
+            _ => false,
+        }
     }
 
     /// Is this a static method?
@@ -960,7 +984,7 @@ pub struct CompInfo {
 
     /// The destructor of this type. The bool represents whether this destructor
     /// is virtual.
-    destructor: Option<(bool, FunctionId)>,
+    destructor: Option<(MethodKind, FunctionId)>,
 
     /// Vector of classes this one inherits from.
     base_members: Vec<Base>,
@@ -1104,7 +1128,7 @@ impl CompInfo {
     }
 
     /// Get this type's destructor.
-    pub fn destructor(&self) -> Option<(bool, FunctionId)> {
+    pub fn destructor(&self) -> Option<(MethodKind, FunctionId)> {
         self.destructor
     }
 
@@ -1355,14 +1379,23 @@ impl CompInfo {
                             ci.constructors.push(signature);
                         }
                         CXCursor_Destructor => {
-                            ci.destructor = Some((is_virtual, signature));
+                            let kind = if is_virtual {
+                                MethodKind::VirtualDestructor {
+                                    pure_virtual: cur.method_is_pure_virtual(),
+                                }
+                            } else {
+                                MethodKind::Destructor
+                            };
+                            ci.destructor = Some((kind, signature));
                         }
                         CXCursor_CXXMethod => {
                             let is_const = cur.method_is_const();
                             let method_kind = if is_static {
                                 MethodKind::Static
                             } else if is_virtual {
-                                MethodKind::Virtual
+                                MethodKind::Virtual {
+                                    pure_virtual: cur.method_is_pure_virtual(),
+                                }
                             } else {
                                 MethodKind::Normal
                             };
@@ -1658,11 +1691,11 @@ impl Trace for CompInfo {
         }
 
         for method in self.methods() {
-            if method.is_destructor() {
-                tracer.visit_kind(method.signature.into(), EdgeKind::Destructor);
-            } else {
-                tracer.visit_kind(method.signature.into(), EdgeKind::Method);
-            }
+            tracer.visit_kind(method.signature.into(), EdgeKind::Method);
+        }
+
+        if let Some((_kind, signature)) = self.destructor() {
+            tracer.visit_kind(signature.into(), EdgeKind::Destructor);
         }
 
         for ctor in self.constructors() {

src/ir/function.rs

@@ -27,17 +27,26 @@ pub enum FunctionKind {
 
 impl FunctionKind {
     fn from_cursor(cursor: &clang::Cursor) -> Option<FunctionKind> {
+        // FIXME(emilio): Deduplicate logic with `ir::comp`.
         Some(match cursor.kind() {
             clang_sys::CXCursor_FunctionDecl => FunctionKind::Function,
             clang_sys::CXCursor_Constructor => FunctionKind::Method(
                 MethodKind::Constructor,
             ),
             clang_sys::CXCursor_Destructor => FunctionKind::Method(
-                MethodKind::Destructor,
+                if cursor.method_is_virtual() {
+                    MethodKind::VirtualDestructor {
+                        pure_virtual: cursor.method_is_pure_virtual(),
+                    }
+                } else {
+                    MethodKind::Destructor
+                }
             ),
             clang_sys::CXCursor_CXXMethod => {
                 if cursor.method_is_virtual() {
-                    FunctionKind::Method(MethodKind::Virtual)
+                    FunctionKind::Method(MethodKind::Virtual {
+                        pure_virtual: cursor.method_is_pure_virtual(),
+                    })
                 } else if cursor.method_is_static() {
                     FunctionKind::Method(MethodKind::Static)
                 } else {

src/ir/item.rs

@@ -944,12 +944,12 @@ impl Item {
                         cc.constructors
                     }
                     FunctionKind::Method(MethodKind::Destructor) |
-                    FunctionKind::Method(MethodKind::VirtualDestructor) => {
+                    FunctionKind::Method(MethodKind::VirtualDestructor { .. }) => {
                         cc.destructors
                     }
                     FunctionKind::Method(MethodKind::Static) |
                     FunctionKind::Method(MethodKind::Normal) |
-                    FunctionKind::Method(MethodKind::Virtual) => cc.methods,
+                    FunctionKind::Method(MethodKind::Virtual { .. }) => cc.methods,
                 }
             }
         }

tests/expectations/tests/issue-1197-pure-virtual-stuff.rs

@@ -0,0 +1,29 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+#[repr(C)]
+pub struct Foo__bindgen_vtable(::std::os::raw::c_void);
+#[repr(C)]
+#[derive(Debug)]
+pub struct Foo {
+    pub vtable_: *const Foo__bindgen_vtable,
+}
+#[test]
+fn bindgen_test_layout_Foo() {
+    assert_eq!(
+        ::std::mem::size_of::<Foo>(),
+        8usize,
+        concat!("Size of: ", stringify!(Foo))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<Foo>(),
+        8usize,
+        concat!("Alignment of ", stringify!(Foo))
+    );
+}
+impl Default for Foo {
+    fn default() -> Self {
+        unsafe { ::std::mem::zeroed() }
+    }
+}

tests/headers/issue-1197-pure-virtual-stuff.hpp

@@ -0,0 +1,6 @@
+class Foo
+{
+public:
+  virtual void Bar() = 0;
+  virtual ~Foo() = 0;
+};

tests/headers/ref_argument_array.hpp

@@ -2,5 +2,5 @@
 #define NSID_LENGTH 10
 class nsID {
 public:
-  virtual void ToProvidedString(char (&aDest)[NSID_LENGTH]) = 0;
+  virtual void ToProvidedString(char (&aDest)[NSID_LENGTH]);
 };