Put vtable generation behind a flag for now.

src/codegen/mod.rs

@@ -1045,7 +1045,8 @@ impl<'a> CodeGenerator for Vtable<'a> {
         // For now, we will only generate vtables for classes that:
         // - do not inherit from others (compilers merge VTable from primary parent class).
         // - do not contain a virtual destructor (requires ordering; platforms generate different vtables).
-        if self.comp_info.base_members().is_empty() &&
+        if ctx.options().vtable_generation &&
+            self.comp_info.base_members().is_empty() &&
             self.comp_info.destructor().is_none()
         {
             let class_ident = ctx.rust_ident(self.item_id.canonical_name(ctx));
@@ -1793,7 +1794,7 @@ impl CodeGenerator for CompInfo {
 
         if !is_opaque {
             if item.has_vtable_ptr(ctx) {
-                let vtable = Vtable::new(item.id(), &self);
+                let vtable = Vtable::new(item.id(), self);
                 vtable.codegen(ctx, result, item);
 
                 let vtable_type = vtable

src/lib.rs

@@ -569,6 +569,10 @@ impl Builder {
             output_vector.push("--explicit-padding".into());
         }
 
+        if self.options.vtable_generation {
+            output_vector.push("--vtable-generation".into());
+        }
+
         // Add clang arguments
 
         output_vector.push("--".into());
@@ -1450,6 +1454,14 @@ impl Builder {
         self
     }
 
+    /// If true, enables experimental support to generate vtable functions.
+    ///
+    /// Should mostly work, though some edge cases are likely to be broken.
+    pub fn vtable_generation(mut self, doit: bool) -> Self {
+        self.options.vtable_generation = doit;
+        self
+    }
+
     /// Generate the Rust bindings using the options built up thus far.
     pub fn generate(mut self) -> Result<Bindings, BindgenError> {
         // Add any extra arguments from the environment to the clang command line.
@@ -1981,6 +1993,9 @@ struct BindgenOptions {
 
     /// Always output explicit padding fields
     force_explicit_padding: bool,
+
+    /// Emit vtable functions.
+    vtable_generation: bool,
 }
 
 /// TODO(emilio): This is sort of a lie (see the error message that results from
@@ -2128,6 +2143,7 @@ impl Default for BindgenOptions {
             translate_enum_integer_types: false,
             c_naming: false,
             force_explicit_padding: false,
+            vtable_generation: false,
         }
     }
 }

src/options.rs

@@ -542,6 +542,9 @@ where
             Arg::new("explicit-padding")
                 .long("explicit-padding")
                 .help("Always output explicit padding fields."),
+            Arg::new("vtable-generation")
+                .long("vtable-generation")
+                .help("Enables generation of vtable functions."),
         ]) // .args()
         .get_matches_from(args);
 
@@ -1008,6 +1011,10 @@ where
         builder = builder.explicit_padding(true);
     }
 
+    if matches.is_present("vtable-generation") {
+        builder = builder.vtable_generation(true);
+    }
+
     let verbose = matches.is_present("verbose");
 
     Ok((builder, output, verbose))

tests/tests.rs

@@ -365,6 +365,7 @@ fn create_bindgen_builder(header: &Path) -> Result<BuilderState, Error> {
         "--no-rustfmt-bindings",
         "--with-derive-default",
         "--disable-header-comment",
+        "--vtable-generation",
         header_str,
         "--raw-line",
         "",