Handle array to pointer decay in union accessor (#211)

Author: lucic71

cpp2rust/converter/models/converter_refcount.cpp

@@ -503,10 +503,13 @@ void ConverterRefCount::EmitRustUnion(clang::RecordDecl *decl) {
   {
     PushBrace impl_brace(*this);
     for (auto *field : decl->fields()) {
+      PushConversionKind push(*this, ConversionKind::FullRefCount);
+      std::string storage_ty = ToString(field->getType());
+      Unwrap(storage_ty, "Value<", ">");
       StrCat(std::format(
           "pub fn {}(&self) -> Ptr<{}> {{ (self.__bytes.as_pointer() "
           "as Ptr<u8>).reinterpret_cast() }}",
-          GetNamedDeclAsString(field), Mapper::Map(field->getType())));
+          GetNamedDeclAsString(field), storage_ty));
     }
   }
 
@@ -1499,6 +1502,7 @@ bool ConverterRefCount::VisitInitListExpr(clang::InitListExpr *expr) {
 }
 
 void ConverterRefCount::ConvertUnionMemberAccessor(clang::MemberExpr *expr) {
+  auto member = expr->getMemberDecl();
   std::string str;
   {
     Buffer buf(*this);
@@ -1509,15 +1513,24 @@ void ConverterRefCount::ConvertUnionMemberAccessor(clang::MemberExpr *expr) {
   str += "()";
 
   if (isAddrOf()) {
-    StrCat(str);
+    if (member->getType()->isArrayType()) {
+      PushConversionKind push(*this, ConversionKind::Unboxed);
+      StrCat(std::format(
+          "{}.reinterpret_cast::<{}>()", str,
+          ToString(
+              member->getType()->getAsArrayTypeUnsafe()->getElementType())));
+    } else {
+      StrCat(str);
+    }
     computed_expr_type_ = ComputedExprType::Pointer;
     return;
   }
+
   if (isLValue()) {
     pending_deref_.set(str);
     return;
   }
-  StrCat(DerefPtrExpr(str, expr->getMemberDecl()->getType()));
+  StrCat(DerefPtrExpr(str, member->getType()));
 }
 
 bool ConverterRefCount::VisitMemberExpr(clang::MemberExpr *expr) {

tests/unit/out/refcount/union_cross_arm_cast.rs

@@ -0,0 +1,202 @@
+extern crate libcc2rs;
+use libcc2rs::*;
+use std::cell::RefCell;
+use std::collections::BTreeMap;
+use std::io::prelude::*;
+use std::io::{Read, Seek, Write};
+use std::os::fd::AsFd;
+use std::rc::{Rc, Weak};
+#[derive()]
+pub struct shape_a {
+    pub code: Value<u16>,
+    pub pad: Value<Box<[u8]>>,
+}
+impl Default for shape_a {
+    fn default() -> Self {
+        shape_a {
+            code: <Value<u16>>::default(),
+            pad: Rc::new(RefCell::new(
+                (0..14).map(|_| <u8>::default()).collect::<Box<[u8]>>(),
+            )),
+        }
+    }
+}
+impl ByteRepr for shape_a {
+    fn byte_size() -> usize {
+        16
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.code.borrow()).to_bytes(&mut buf[0..2]);
+        (*self.pad.borrow()).to_bytes(&mut buf[2..16]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            code: Rc::new(RefCell::new(<u16>::from_bytes(&buf[0..2]))),
+            pad: Rc::new(RefCell::new(<Box<[u8]>>::from_bytes(&buf[2..16]))),
+        }
+    }
+}
+#[derive()]
+pub struct shape_b {
+    pub code: Value<u16>,
+    pub lo: Value<u16>,
+    pub mid: Value<u32>,
+    pub fill: Value<Box<[u8]>>,
+    pub tail: Value<u32>,
+}
+impl Default for shape_b {
+    fn default() -> Self {
+        shape_b {
+            code: <Value<u16>>::default(),
+            lo: <Value<u16>>::default(),
+            mid: <Value<u32>>::default(),
+            fill: Rc::new(RefCell::new(
+                (0..16).map(|_| <u8>::default()).collect::<Box<[u8]>>(),
+            )),
+            tail: <Value<u32>>::default(),
+        }
+    }
+}
+impl ByteRepr for shape_b {
+    fn byte_size() -> usize {
+        28
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.code.borrow()).to_bytes(&mut buf[0..2]);
+        (*self.lo.borrow()).to_bytes(&mut buf[2..4]);
+        (*self.mid.borrow()).to_bytes(&mut buf[4..8]);
+        (*self.fill.borrow()).to_bytes(&mut buf[8..24]);
+        (*self.tail.borrow()).to_bytes(&mut buf[24..28]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            code: Rc::new(RefCell::new(<u16>::from_bytes(&buf[0..2]))),
+            lo: Rc::new(RefCell::new(<u16>::from_bytes(&buf[2..4]))),
+            mid: Rc::new(RefCell::new(<u32>::from_bytes(&buf[4..8]))),
+            fill: Rc::new(RefCell::new(<Box<[u8]>>::from_bytes(&buf[8..24]))),
+            tail: Rc::new(RefCell::new(<u32>::from_bytes(&buf[24..28]))),
+        }
+    }
+}
+pub struct anon_0 {
+    __bytes: Value<Box<[u8]>>,
+}
+impl anon_0 {
+    pub fn a(&self) -> Ptr<shape_a> {
+        (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
+    }
+    pub fn b(&self) -> Ptr<shape_b> {
+        (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
+    }
+    pub fn raw_(&self) -> Ptr<Box<[u8]>> {
+        (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
+    }
+}
+impl Clone for anon_0 {
+    fn clone(&self) -> Self {
+        anon_0 {
+            __bytes: Rc::new(RefCell::new(self.__bytes.borrow().clone())),
+        }
+    }
+}
+impl Default for anon_0 {
+    fn default() -> Self {
+        anon_0 {
+            __bytes: Rc::new(RefCell::new(Box::from([0u8; 64]))),
+        }
+    }
+}
+impl ByteRepr for anon_0 {
+    fn byte_size() -> usize {
+        64
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        buf.copy_from_slice(&self.__bytes.borrow());
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        anon_0 {
+            __bytes: Rc::new(RefCell::new(Box::from(buf))),
+        }
+    }
+}
+#[derive(Default)]
+pub struct Container {
+    pub len: Value<u32>,
+    pub u: Value<anon_0>,
+}
+impl ByteRepr for Container {
+    fn byte_size() -> usize {
+        68
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.len.borrow()).to_bytes(&mut buf[0..4]);
+        (*self.u.borrow()).to_bytes(&mut buf[4..68]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            len: Rc::new(RefCell::new(<u32>::from_bytes(&buf[0..4]))),
+            u: Rc::new(RefCell::new(<anon_0>::from_bytes(&buf[4..68]))),
+        }
+    }
+}
+pub fn main() {
+    std::process::exit(main_0());
+}
+fn main_0() -> i32 {
+    let c: Value<Container> = <Value<Container>>::default();
+    {
+        ((c.as_pointer()) as Ptr<Container>)
+            .to_any()
+            .memset((0) as u8, 68usize as usize);
+        ((c.as_pointer()) as Ptr<Container>).to_any().clone()
+    };
+    (*(*(*(*c.borrow()).u.borrow()).a().upgrade().deref())
+        .code
+        .borrow_mut()) = 10_u16;
+    (*(*c.borrow()).len.borrow_mut()) = (28usize as u32);
+    (*(*(((*(*c.borrow()).u.borrow()).a())
+        .clone()
+        .to_any()
+        .cast::<shape_b>()
+        .expect("ub:wrong type"))
+    .upgrade()
+    .deref())
+    .tail
+    .borrow_mut()) = 3735928559_u32;
+    assert!(
+        ((((*(*(*(*c.borrow()).u.borrow()).b().upgrade().deref())
+            .tail
+            .borrow())
+            == 3735928559_u32) as i32)
+            != 0)
+    );
+    assert!(
+        (((((*(*(*(*c.borrow()).u.borrow()).b().upgrade().deref())
+            .code
+            .borrow()) as i32)
+            == 10) as i32)
+            != 0)
+    );
+    (*(*(*(*c.borrow()).u.borrow()).b().upgrade().deref())
+        .lo
+        .borrow_mut()) = 8080_u16;
+    assert!(
+        ((((((((*(*c.borrow()).u.borrow()).raw_().reinterpret_cast::<u8>())
+            .to_strong()
+            .as_pointer() as Ptr::<u8>)
+            .offset((2) as isize)
+            .read()) as i32)
+            == 144) as i32)
+            != 0)
+    );
+    assert!(
+        ((((((((*(*c.borrow()).u.borrow()).raw_().reinterpret_cast::<u8>())
+            .to_strong()
+            .as_pointer() as Ptr::<u8>)
+            .offset((3) as isize)
+            .read()) as i32)
+            == 31) as i32)
+            != 0)
+    );
+    return 0;
+}