codegen: Generate u128 / i128 when available.

3 files changed, 69 insertions, 5 deletions

diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index 8aa8d348..86a29c50 100644
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -3059,11 +3059,21 @@ impl TryToRustTy for Type {
                             #ident
                         })
                     }
-                    // FIXME: This doesn't generate the proper alignment, but we
-                    // can't do better right now. We should be able to use
-                    // i128/u128 when they're available.
-                    IntKind::U128 | IntKind::I128 => {
-                        Ok(quote! { [u64; 2] })
+                    IntKind::U128 => {
+                        Ok(if ctx.options().rust_features.i128_and_u128 {
+                            quote! { u128 }
+                        } else {
+                            // Best effort thing, but wrong alignment
+                            // unfortunately.
+                            quote! { [u64; 2] }
+                        })
+                    }
+                    IntKind::I128 => {
+                        Ok(if ctx.options().rust_features.i128_and_u128 {
+                            quote! { i128 }
+                        } else {
+                            quote! { [u64; 2] }
+                        })
                     }
                 }
             }
diff --git a/tests/expectations/tests/i128.rs b/tests/expectations/tests/i128.rs
new file mode 100644
index 00000000..cd91f141
--- /dev/null
+++ b/tests/expectations/tests/i128.rs
@@ -0,0 +1,48 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct foo {
+    pub my_signed: i128,
+    pub my_unsigned: u128,
+}
+#[test]
+fn bindgen_test_layout_foo() {
+    assert_eq!(
+        ::std::mem::size_of::<foo>(),
+        32usize,
+        concat!("Size of: ", stringify!(foo))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<foo>(),
+        16usize,
+        concat!("Alignment of ", stringify!(foo))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<foo>())).my_signed as *const _ as usize },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(foo),
+            "::",
+            stringify!(my_signed)
+        )
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<foo>())).my_unsigned as *const _ as usize },
+        16usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(foo),
+            "::",
+            stringify!(my_unsigned)
+        )
+    );
+}
diff --git a/tests/headers/i128.h b/tests/headers/i128.h
new file mode 100644
index 00000000..6ec399c7
--- /dev/null
+++ b/tests/headers/i128.h
@@ -0,0 +1,6 @@
+// bindgen-flags: --rust-target 1.26
+
+struct foo {
+  __int128 my_signed;
+  unsigned __int128 my_unsigned;
+};