Add option to avoid wrapping function pointer fields

CHANGELOG.md

@@ -152,6 +152,8 @@
 # Unreleased
 
 ## Added
+ * Do not wrap function pointer fields in `Option` if the new
+   `--dont-wrap-fn-ptr-fields` option is enabled.
 
 ## Changed
 

bindgen-cli/options.rs

@@ -565,6 +565,9 @@ where
             Arg::new("wrap-unsafe-ops")
                 .long("wrap-unsafe-ops")
                 .help("Wrap unsafe operations in unsafe blocks."),
+            Arg::new("dont-wrap-fn-ptr-fields")
+                .long("dont-wrap-fn-ptr-fields")
+                .help("Do not wrap function pointer fields in `Option`."),
             Arg::new("V")
                 .long("version")
                 .help("Prints the version, and exits"),
@@ -1092,5 +1095,9 @@ where
         builder = builder.wrap_unsafe_ops(true);
     }
 
+    if matches.is_present("dont-wrap-fn-ptr-fields") {
+        builder = builder.wrap_fn_ptr_fields(false);
+    }
+
     Ok((builder, output, verbose))
 }

bindgen-tests/tests/headers/dont-wrap-fn-ptr-fields.h

@@ -0,0 +1,5 @@
+// bindgen-flags: --dont-wrap-fn-ptr-fields --no-default="foo"
+
+typedef struct foo {
+    int (*bar)();
+} foo;

bindgen/codegen/mod.rs

@@ -3762,10 +3762,12 @@ impl TryToRustTy for Type {
                 // variant here.
                 let ty = fs.try_to_rust_ty(ctx, &())?;
 
-                let prefix = ctx.trait_prefix();
-                Ok(quote! {
-                    ::#prefix::option::Option<#ty>
-                })
+                if ctx.options().wrap_fn_ptr_fields {
+                    let prefix = ctx.trait_prefix();
+                    Ok(quote!(::#prefix::option::Option<#ty>))
+                } else {
+                    Ok(quote!(#ty))
+                }
             }
             TypeKind::Array(item, len) | TypeKind::Vector(item, len) => {
                 let ty = item.try_to_rust_ty(ctx, &())?;

bindgen/lib.rs

@@ -649,6 +649,10 @@ impl Builder {
             output_vector.push("--wrap-unsafe-ops".into());
         }
 
+        if !self.options.wrap_fn_ptr_fields {
+            output_vector.push("--dont-wrap-fn-ptr-fields".into());
+        }
+
         // Add clang arguments
 
         output_vector.push("--".into());
@@ -1787,6 +1791,12 @@ impl Builder {
         self.options.wrap_unsafe_ops = doit;
         self
     }
+
+    /// If true, wraps function pointer fields in `Option`.
+    pub fn wrap_fn_ptr_fields(mut self, doit: bool) -> Self {
+        self.options.wrap_fn_ptr_fields = doit;
+        self
+    }
 }
 
 /// Configuration options for generated bindings.
@@ -2127,6 +2137,9 @@ struct BindgenOptions {
 
     /// Whether to wrap unsafe operations in unsafe blocks or not.
     wrap_unsafe_ops: bool,
+
+    /// Whether to wrap function pointer fields in `Option` or not.
+    wrap_fn_ptr_fields: bool,
 }
 
 impl BindgenOptions {
@@ -2238,6 +2251,7 @@ impl Default for BindgenOptions {
             record_matches: true,
             rustfmt_bindings: true,
             size_t_is_usize: true,
+            wrap_fn_ptr_fields: true,
 
             --default-fields--
             blocklisted_types,