Merge pull request #1313 from google/bitfieldthing

Explicitly reject bitfields

Author: adetaylor

engine/src/conversion/analysis/pod/byvalue_checker.rs

@@ -158,6 +158,12 @@ impl ByValueChecker {
                     ));
                     break;
                 }
+                None if ty_id.get_final_item() == "__BindgenBitfieldUnit" => {
+                    field_safety_problem = PodState::UnsafeToBePod(format!(
+                        "Type {tyname} could not be POD because it is a bitfield"
+                    ));
+                    break;
+                }
                 None => {
                     field_safety_problem = PodState::UnsafeToBePod(format!(
                         "Type {tyname} could not be POD because its dependent type {ty_id} isn't known"

engine/src/types.rs

@@ -236,6 +236,10 @@ impl std::fmt::Debug for QualifiedName {
 /// cxx.
 #[derive(Error, Clone, Debug)]
 pub enum InvalidIdentError {
+    #[error("Union are not supported by autocxx (and their bindgen names have __ so are not acceptable to cxx)")]
+    Union,
+    #[error("Bitfields are not supported by autocxx (and their bindgen names have __ so are not acceptable to cxx)")]
+    Bitfield,
     #[error("Names containing __ are reserved by C++ so not acceptable to cxx")]
     TooManyUnderscores,
     #[error("bindgen decided to call this type _bindgen_ty_N because it couldn't deduce the correct name for it. That means we can't generate C++ bindings to it.")]
@@ -251,7 +255,12 @@ pub enum InvalidIdentError {
 /// where code will be output as part of the `#[cxx::bridge]` mod.
 pub fn validate_ident_ok_for_cxx(id: &str) -> Result<(), InvalidIdentError> {
     validate_ident_ok_for_rust(id)?;
-    if id.contains("__") {
+    // Provide a couple of more specific diagnostics if we can.
+    if id.starts_with("__BindgenBitfieldUnit") {
+        Err(InvalidIdentError::Bitfield)
+    } else if id.starts_with("__BindgenUnionField") {
+        Err(InvalidIdentError::Union)
+    } else if id.contains("__") {
         Err(InvalidIdentError::TooManyUnderscores)
     } else if id.starts_with("_bindgen_ty_") {
         Err(InvalidIdentError::BindgenTy)

integration-tests/tests/integration_test.rs

@@ -12241,6 +12241,45 @@ fn test_ignore_va_list() {
     run_test("", hdr, rs, &["A"], &[]);
 }
 
+#[test]
+fn test_cpp_union_pod() {
+    let hdr = indoc! {"
+        typedef unsigned long long UInt64_t;
+        struct ManagedPtr_t_;
+        typedef struct ManagedPtr_t_ ManagedPtr_t;
+        
+        typedef int (*ManagedPtr_ManagerFunction_t)(
+                ManagedPtr_t *managedPtr,
+                const ManagedPtr_t *srcPtr,
+                int operation);
+        
+        typedef union {
+            int intValue;
+            void *ptr;
+        } ManagedPtr_t_data_;
+        
+        struct ManagedPtr_t_ {
+            void *pointer;
+            ManagedPtr_t_data_ userData[4];
+            ManagedPtr_ManagerFunction_t manager;
+        };
+        
+        typedef struct CorrelationId_t_ {
+            unsigned int size : 8;
+            unsigned int valueType : 4;
+            unsigned int classId : 16;
+            unsigned int reserved : 4;
+        
+            union {
+                UInt64_t intValue;
+                ManagedPtr_t ptrValue;
+            } value;
+        } CorrelationId_t;
+    "};
+    run_test("", hdr, quote! {}, &["CorrelationId_t_"], &[]);
+    run_test_expect_fail("", hdr, quote! {}, &[], &["CorrelationId_t_"]);
+}
+
 // Yet to test:
 // - Ifdef
 // - Out param pointers