Add flag to ignore type blocklist when computing derive information

Fixes #1454

Author: Jethro Beekman

src/ir/analysis/derive.rs

@@ -138,8 +138,9 @@ impl<'ctx> CannotDerive<'ctx> {
     }
 
     fn constrain_type(&mut self, item: &Item, ty: &Type) -> CanDerive {
-        if !self.ctx.allowlisted_items().contains(&item.id()) {
-            trace!(
+        if !self.ctx.options().derive_ignore_blocklist &&
+            !self.ctx.allowlisted_items().contains(&item.id())
+        {            trace!(
                 "    cannot derive {} for blocklisted type",
                 self.derive_trait
             );

src/lib.rs

@@ -549,6 +549,10 @@ impl Builder {
             output_vector.push("--respect-cxx-access-specs".into());
         }
 
+        if self.options.derive_ignore_blocklist {
+            output_vector.push("--derive-ignore-blocklist".into());
+        }
+
         // Add clang arguments
 
         output_vector.push("--".into());
@@ -1568,6 +1572,12 @@ impl Builder {
         self.options.respect_cxx_access_specs = doit;
         self
     }
+
+    /// Ignore the type blocklist when computing type derive information
+    pub fn derive_ignore_blocklist(mut self, doit: bool) -> Self {
+        self.options.derive_ignore_blocklist = doit;
+        self
+    }
 }
 
 /// Configuration options for generated bindings.
@@ -1859,6 +1869,9 @@ struct BindgenOptions {
     /// Only make generated bindings `pub` if the items would be publically accessible
     /// by C++.
     respect_cxx_access_specs: bool,
+
+    /// Ignore the type blocklist when computing type derive information
+    derive_ignore_blocklist: bool,
 }
 
 /// TODO(emilio): This is sort of a lie (see the error message that results from
@@ -1996,6 +2009,7 @@ impl Default for BindgenOptions {
             wasm_import_module_name: None,
             dynamic_library_name: None,
             respect_cxx_access_specs: false,
+            derive_ignore_blocklist: false,
         }
     }
 }

src/options.rs

@@ -503,6 +503,9 @@ where
             Arg::with_name("respect-cxx-access-specs")
                 .long("respect-cxx-access-specs")
                 .help("Makes generated bindings `pub` only for items if the items are publically accessible in C++."),
+            Arg::with_name("derive-ignore-blocklist")
+                .long("derive-ignore-blocklist")
+                .help("Ignore the type blocklist when computing type derive information"),
         ]) // .args()
         .get_matches_from(args);
 
@@ -929,6 +932,10 @@ where
         builder = builder.respect_cxx_access_specs(true);
     }
 
+    if matches.is_present("derive-ignore-blocklist") {
+        builder = builder.derive_ignore_blocklist(true);
+    }
+
     let verbose = matches.is_present("verbose");
 
     Ok((builder, output, verbose))

tests/expectations/tests/issue-1454.rs

@@ -0,0 +1,81 @@
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct rlimit;
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct my_rlimit_conf {
+    pub core: rlimit,
+    pub cpu: rlimit,
+    pub data: rlimit,
+    pub fsize: rlimit,
+}
+#[test]
+fn bindgen_test_layout_my_rlimit_conf() {
+    assert_eq!(
+        ::std::mem::size_of::<my_rlimit_conf>(),
+        0usize,
+        concat!("Size of: ", stringify!(my_rlimit_conf))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<my_rlimit_conf>(),
+        1usize,
+        concat!("Alignment of ", stringify!(my_rlimit_conf))
+    );
+    assert_eq!(
+        unsafe {
+            &(*(::std::ptr::null::<my_rlimit_conf>())).core as *const _ as usize
+        },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(my_rlimit_conf),
+            "::",
+            stringify!(core)
+        )
+    );
+    assert_eq!(
+        unsafe {
+            &(*(::std::ptr::null::<my_rlimit_conf>())).cpu as *const _ as usize
+        },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(my_rlimit_conf),
+            "::",
+            stringify!(cpu)
+        )
+    );
+    assert_eq!(
+        unsafe {
+            &(*(::std::ptr::null::<my_rlimit_conf>())).data as *const _ as usize
+        },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(my_rlimit_conf),
+            "::",
+            stringify!(data)
+        )
+    );
+    assert_eq!(
+        unsafe {
+            &(*(::std::ptr::null::<my_rlimit_conf>())).fsize as *const _
+                as usize
+        },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(my_rlimit_conf),
+            "::",
+            stringify!(fsize)
+        )
+    );
+}

tests/headers/issue-1454.h

@@ -0,0 +1,12 @@
+// bindgen-flags: --no-recursive-allowlist --allowlist-type "my_rlimit_conf" --derive-ignore-blocklist --raw-line "#[repr(C)] #[derive(Debug, Default, Copy, Clone)] pub struct rlimit;"
+
+struct rlimit {};
+
+typedef struct
+{
+    struct rlimit core;
+    struct rlimit cpu;
+    struct rlimit data;
+    struct rlimit fsize;
+}
+my_rlimit_conf;