Translate access of union array members as Ptr<T> instead of Ptr<Box<[T]>> (#218)

Author: lucic71

cpp2rust/converter/converter_lib.cpp

@@ -130,6 +130,16 @@ bool IsInMainFile(const clang::Decl *decl) {
   return src_mgr.isInMainFile(src_mgr.getExpansionLoc(loc));
 }
 
+bool IsUnionArrayMember(const clang::Expr *base) {
+  if (auto *me =
+          clang::dyn_cast<clang::MemberExpr>(base->IgnoreParenImpCasts())) {
+    if (auto *fd = clang::dyn_cast<clang::FieldDecl>(me->getMemberDecl())) {
+      return fd->getParent()->isUnion() && fd->getType()->isArrayType();
+    }
+  }
+  return false;
+}
+
 bool IsUserDefinedDecl(const clang::Decl *decl) {
   const auto &ctx = decl->getASTContext();
   const auto &src_mgr = ctx.getSourceManager();

cpp2rust/converter/converter_lib.h

@@ -40,6 +40,8 @@ bool IsComparisonWithNullOp(const clang::BinaryOperator *expr);
 
 bool IsInMainFile(const clang::Decl *decl);
 
+bool IsUnionArrayMember(const clang::Expr *base);
+
 bool IsUserDefinedDecl(const clang::Decl *decl);
 
 bool RefersToUserDefinedDecl(const clang::Expr *expr);

cpp2rust/converter/models/converter_refcount.cpp

@@ -378,7 +378,8 @@ std::string ConverterRefCount::ConvertPtrType(clang::QualType type) {
 bool ConverterRefCount::VisitArraySubscriptExpr(
     clang::ArraySubscriptExpr *expr) {
   auto *base = expr->getBase();
-  if (base->IgnoreCasts()->getType()->isPointerType()) {
+  if (base->IgnoreCasts()->getType()->isPointerType() ||
+      IsUnionArrayMember(base)) {
     ConvertPointerSubscript(expr);
   } else {
     if (!base->IgnoreCasts()->getType()->isArrayType()) {
@@ -504,13 +505,16 @@ 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<", ">");
+      PushConversionKind push(*this, ConversionKind::Unboxed);
+      auto ty =
+          field->getType()->isArrayType()
+              ? ToString(
+                    field->getType()->getAsArrayTypeUnsafe()->getElementType())
+              : ToString(field->getType());
       StrCat(std::format(
           "pub fn {}(&self) -> Ptr<{}> {{ (self.__bytes.as_pointer() "
           "as Ptr<u8>).reinterpret_cast() }}",
-          GetNamedDeclAsString(field), storage_ty));
+          GetNamedDeclAsString(field), ty));
     }
   }
 

tests/unit/out/refcount/union_addrof_external.rs

@@ -51,7 +51,7 @@ impl anon_0 {
     pub fn h(&self) -> Ptr<record> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
-    pub fn raw_(&self) -> Ptr<Box<[u8]>> {
+    pub fn raw_(&self) -> Ptr<u8> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
 }
@@ -187,12 +187,21 @@ fn main_0() -> i32 {
             != 0)
     );
     assert!(
-        ((((((*(*c.borrow()).view.borrow()).raw_().read())[(0) as usize] as i32) == 2) as i32)
+        (((((((*(*c.borrow()).view.borrow())
+            .raw_()
+            .reinterpret_cast::<u8>() as Ptr::<u8>)
+            .offset((0) as isize)
+            .read()) as i32)
+            == 2) as i32)
             != 0)
     );
     assert!(
-        (((((((*(*c.borrow()).view.borrow()).raw_().read())[(3) as usize] as u8) as i32) == 80)
-            as i32)
+        ((((((((*(*c.borrow()).view.borrow())
+            .raw_()
+            .reinterpret_cast::<u8>() as Ptr::<u8>)
+            .offset((3) as isize)
+            .read()) as u8) as i32)
+            == 80) as i32)
             != 0)
     );
     return 0;

tests/unit/out/refcount/union_cross_arm_cast.rs

@@ -88,7 +88,7 @@ impl anon_0 {
     pub fn b(&self) -> Ptr<shape_b> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
-    pub fn raw_(&self) -> Ptr<Box<[u8]>> {
+    pub fn raw_(&self) -> Ptr<u8> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
 }

tests/unit/out/refcount/union_field_alignment.rs

@@ -0,0 +1,84 @@
+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};
+pub struct anon_0 {
+    __bytes: Value<Box<[u8]>>,
+}
+impl anon_0 {
+    pub fn bytes(&self) -> Ptr<u8> {
+        (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
+    }
+    pub fn aligner(&self) -> Ptr<AnyPtr> {
+        (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; 8]))),
+        }
+    }
+}
+impl ByteRepr for anon_0 {
+    fn byte_size() -> usize {
+        8
+    }
+    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 node {
+    pub next: Value<Ptr<node>>,
+    pub x: Value<anon_0>,
+}
+impl ByteRepr for node {
+    fn byte_size() -> usize {
+        16
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.next.borrow()).to_bytes(&mut buf[0..8]);
+        (*self.x.borrow()).to_bytes(&mut buf[8..16]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            next: Rc::new(RefCell::new(<Ptr<node>>::from_bytes(&buf[0..8]))),
+            x: Rc::new(RefCell::new(<anon_0>::from_bytes(&buf[8..16]))),
+        }
+    }
+}
+pub fn main() {
+    std::process::exit(main_0());
+}
+fn main_0() -> i32 {
+    let n: Value<node> = <Value<node>>::default();
+    (*(*n.borrow()).next.borrow_mut()) = Ptr::<node>::null();
+    ((*(*n.borrow()).x.borrow()).bytes().reinterpret_cast::<u8>() as Ptr<u8>)
+        .offset((0) as isize)
+        .write(171_u8);
+    assert!(
+        (((((((*(*n.borrow()).x.borrow()).bytes().reinterpret_cast::<u8>() as Ptr::<u8>)
+            .offset((0) as isize)
+            .read()) as i32)
+            == 171) as i32)
+            != 0)
+    );
+    return 0;
+}

tests/unit/out/refcount/union_memset_memcpy.rs

@@ -84,7 +84,7 @@ impl anon_0 {
     pub fn b(&self) -> Ptr<shape_b> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
-    pub fn raw_(&self) -> Ptr<Box<[u8]>> {
+    pub fn raw_(&self) -> Ptr<u8> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
 }
@@ -158,11 +158,21 @@ fn main_0() -> i32 {
             != 0)
     );
     assert!(
-        ((((((*(*c.borrow()).view.borrow()).raw_().read())[(0) as usize] as i32) == 0) as i32)
+        (((((((*(*c.borrow()).view.borrow())
+            .raw_()
+            .reinterpret_cast::<u8>() as Ptr::<u8>)
+            .offset((0) as isize)
+            .read()) as i32)
+            == 0) as i32)
             != 0)
     );
     assert!(
-        ((((((*(*c.borrow()).view.borrow()).raw_().read())[(255) as usize] as i32) == 0) as i32)
+        (((((((*(*c.borrow()).view.borrow())
+            .raw_()
+            .reinterpret_cast::<u8>() as Ptr::<u8>)
+            .offset((255) as isize)
+            .read()) as i32)
+            == 0) as i32)
             != 0)
     );
     let src: Value<Box<[u8]>> = Rc::new(RefCell::new(Box::new([

tests/unit/out/refcount/union_nested.rs

@@ -43,7 +43,7 @@ impl anon_0 {
     pub fn h(&self) -> Ptr<record> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
-    pub fn raw_(&self) -> Ptr<Box<[u8]>> {
+    pub fn raw_(&self) -> Ptr<u8> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
 }

tests/unit/out/refcount/union_struct_dual_use.rs

@@ -40,7 +40,7 @@ impl anon_1 {
     pub fn inner(&self) -> Ptr<Inner> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
-    pub fn raw_(&self) -> Ptr<Box<[u8]>> {
+    pub fn raw_(&self) -> Ptr<u8> {
         (self.__bytes.as_pointer() as Ptr<u8>).reinterpret_cast()
     }
 }
@@ -114,13 +114,21 @@ fn main_0() -> i32 {
             != 0)
     );
     assert!(
-        (((((((*(*outer.borrow()).u.borrow()).raw_().read())[(0) as usize] as u8) as i32) == 3)
-            as i32)
+        ((((((((*(*outer.borrow()).u.borrow())
+            .raw_()
+            .reinterpret_cast::<u8>() as Ptr::<u8>)
+            .offset((0) as isize)
+            .read()) as u8) as i32)
+            == 3) as i32)
             != 0)
     );
     assert!(
-        (((((((*(*outer.borrow()).u.borrow()).raw_().read())[(4) as usize] as u8) as i32) == 4)
-            as i32)
+        ((((((((*(*outer.borrow()).u.borrow())
+            .raw_()
+            .reinterpret_cast::<u8>() as Ptr::<u8>)
+            .offset((4) as isize)
+            .read()) as u8) as i32)
+            == 4) as i32)
             != 0)
     );
     return 0;

tests/unit/union_field_alignment.c

@@ -1,4 +1,3 @@
-// no-compile: refcount
 #include <assert.h>
 #include <stddef.h>
 #include <stdint.h>