Rename load_value_pair to load_scalar_pair and fix dynamic dispatch with arbitrary self types

example/arbitrary_self_types_pointers_and_wrappers.rs

@@ -0,0 +1,83 @@
+// Adapted from rustc run-pass test suite
+
+#![feature(no_core, arbitrary_self_types, box_syntax)]
+#![feature(rustc_attrs)]
+
+#![feature(start, lang_items)]
+#![no_core]
+
+extern crate mini_core;
+
+use mini_core::*;
+use mini_core::libc::*;
+
+macro_rules! assert_eq {
+    ($l:expr, $r: expr) => {
+        if $l != $r {
+            panic(&(stringify!($l != $r), file!(), line!(), 0));
+        }
+    }
+}
+
+struct Ptr<T: ?Sized>(Box<T>);
+
+impl<T: ?Sized> Deref for Ptr<T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        &*self.0
+    }
+}
+
+impl<T: Unsize<U> + ?Sized, U: ?Sized> CoerceUnsized<Ptr<U>> for Ptr<T> {}
+impl<T: Unsize<U> + ?Sized, U: ?Sized> DispatchFromDyn<Ptr<U>> for Ptr<T> {}
+
+struct Wrapper<T: ?Sized>(T);
+
+impl<T: ?Sized> Deref for Wrapper<T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        &self.0
+    }
+}
+
+impl<T: CoerceUnsized<U>, U> CoerceUnsized<Wrapper<U>> for Wrapper<T> {}
+impl<T: DispatchFromDyn<U>, U> DispatchFromDyn<Wrapper<U>> for Wrapper<T> {}
+
+
+trait Trait {
+    // This method isn't object-safe yet. Unsized by-value `self` is object-safe (but not callable
+    // without unsized_locals), but wrappers arond `Self` currently are not.
+    // FIXME (mikeyhew) uncomment this when unsized rvalues object-safety is implemented
+    // fn wrapper(self: Wrapper<Self>) -> i32;
+    fn ptr_wrapper(self: Ptr<Wrapper<Self>>) -> i32;
+    fn wrapper_ptr(self: Wrapper<Ptr<Self>>) -> i32;
+    fn wrapper_ptr_wrapper(self: Wrapper<Ptr<Wrapper<Self>>>) -> i32;
+}
+
+impl Trait for i32 {
+    fn ptr_wrapper(self: Ptr<Wrapper<Self>>) -> i32 {
+        **self
+    }
+    fn wrapper_ptr(self: Wrapper<Ptr<Self>>) -> i32 {
+        **self
+    }
+    fn wrapper_ptr_wrapper(self: Wrapper<Ptr<Wrapper<Self>>>) -> i32 {
+        ***self
+    }
+}
+
+#[start]
+fn main(_: isize, _: *const *const u8) -> isize {
+    let pw = Ptr(box Wrapper(5)) as Ptr<Wrapper<dyn Trait>>;
+    assert_eq!(pw.ptr_wrapper(), 5);
+
+    let wp = Wrapper(Ptr(box 6)) as Wrapper<Ptr<dyn Trait>>;
+    assert_eq!(wp.wrapper_ptr(), 6);
+
+    let wpw = Wrapper(Ptr(box Wrapper(7))) as Wrapper<Ptr<Wrapper<dyn Trait>>>;
+    assert_eq!(wpw.wrapper_ptr_wrapper(), 7);
+
+    0
+}

example/mini_core.rs

@@ -27,6 +27,7 @@ impl<'a, T: ?Sized+Unsize<U>, U: ?Sized> DispatchFromDyn<&'a mut U> for &'a mut
 impl<T: ?Sized+Unsize<U>, U: ?Sized> DispatchFromDyn<*const U> for *const T {}
 // *mut T -> *mut U
 impl<T: ?Sized+Unsize<U>, U: ?Sized> DispatchFromDyn<*mut U> for *mut T {}
+impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U>> for Box<T> {}
 
 #[lang = "receiver"]
 pub trait Receiver {}
@@ -216,6 +217,15 @@ impl PartialEq for usize {
     }
 }
 
+impl PartialEq for i32 {
+    fn eq(&self, other: &i32) -> bool {
+        (*self) == (*other)
+    }
+    fn ne(&self, other: &i32) -> bool {
+        (*self) != (*other)
+    }
+}
+
 impl PartialEq for isize {
     fn eq(&self, other: &isize) -> bool {
         (*self) == (*other)
@@ -306,6 +316,13 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
     drop_in_place(to_drop);
 }
 
+#[lang = "deref"]
+pub trait Deref {
+    type Target: ?Sized;
+
+    fn deref(&self) -> &Self::Target;
+}
+
 #[lang = "owned_box"]
 pub struct Box<T: ?Sized>(*mut T);
 
@@ -317,6 +334,14 @@ impl<T: ?Sized> Drop for Box<T> {
     }
 }
 
+impl<T> Deref for Box<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &**self
+    }
+}
+
 #[lang = "exchange_malloc"]
 // Make it available to jited mini_core_hello_world
 // FIXME remove next line when jit supports linking rlibs

src/base.rs

@@ -537,7 +537,7 @@ fn trans_stmt<'a, 'tcx: 'a>(
                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
                         } else {
                             // fat-ptr -> thin-ptr
-                            let (ptr, _extra) = operand.load_value_pair(fx);
+                            let (ptr, _extra) = operand.load_scalar_pair(fx);
                             lval.write_cvalue(fx, CValue::ByVal(ptr, dest_layout))
                         }
                     } else if let ty::Adt(adt_def, _substs) = from_ty.sty {
@@ -1101,8 +1101,8 @@ fn trans_ptr_binop<'a, 'tcx: 'a>(
             Offset (_) bug; // Handled above
         }
     } else {
-        let (lhs_ptr, lhs_extra) = lhs.load_value_pair(fx);
-        let (rhs_ptr, rhs_extra) = rhs.load_value_pair(fx);
+        let (lhs_ptr, lhs_extra) = lhs.load_scalar_pair(fx);
+        let (rhs_ptr, rhs_extra) = rhs.load_scalar_pair(fx);
         let res = match bin_op {
             BinOp::Eq => {
                 let ptr_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_ptr, rhs_ptr);

src/common.rs

@@ -166,33 +166,33 @@ impl<'tcx> CValue<'tcx> {
                 fx.bcx.ins().load(clif_ty, MemFlags::new(), addr, 0)
             }
             CValue::ByVal(value, _layout) => value,
-            CValue::ByValPair(_, _, _layout) => bug!("Please use load_value_pair for ByValPair"),
+            CValue::ByValPair(_, _, _layout) => bug!("Please use load_scalar_pair for ByValPair"),
         }
     }
 
-    pub fn load_value_pair<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> (Value, Value)
+    /// Load a value pair with layout.abi of scalar pair
+    pub fn load_scalar_pair<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> (Value, Value)
     where
         'tcx: 'a,
     {
         match self {
             CValue::ByRef(addr, layout) => {
-                assert_eq!(
-                    layout.size.bytes(),
-                    fx.tcx.data_layout.pointer_size.bytes() * 2
+                let (a, b) = match &layout.abi {
+                    layout::Abi::ScalarPair(a, b) => (a.clone(), b.clone()),
+                    _ => unreachable!(),
+                };
+                let clif_ty1 = crate::abi::scalar_to_clif_type(fx.tcx, a.clone());
+                let clif_ty2 = crate::abi::scalar_to_clif_type(fx.tcx, b);
+                let val1 = fx.bcx.ins().load(clif_ty1, MemFlags::new(), addr, 0);
+                let val2 = fx.bcx.ins().load(
+                    clif_ty2,
+                    MemFlags::new(),
+                    addr,
+                    a.value.size(&fx.tcx).bytes() as i32,
                 );
-                let val1_offset = layout.fields.offset(0).bytes() as i32;
-                let val2_offset = layout.fields.offset(1).bytes() as i32;
-                let val1 = fx
-                    .bcx
-                    .ins()
-                    .load(fx.pointer_type, MemFlags::new(), addr, val1_offset);
-                let val2 = fx
-                    .bcx
-                    .ins()
-                    .load(fx.pointer_type, MemFlags::new(), addr, val2_offset);
                 (val1, val2)
             }
-            CValue::ByVal(_, _layout) => bug!("Please use load_value for ByVal"),
+            CValue::ByVal(_, _layout) => bug!("Please use load_scalar for ByVal"),
             CValue::ByValPair(val1, val2, _layout) => (val1, val2),
         }
     }

src/intrinsics.rs

@@ -156,7 +156,7 @@ pub fn codegen_intrinsic_call<'a, 'tcx: 'a>(
         size_of_val, <T> (c ptr) {
             let layout = fx.layout_of(T);
             let size = if layout.is_unsized() {
-                let (_ptr, info) = ptr.load_value_pair(fx);
+                let (_ptr, info) = ptr.load_scalar_pair(fx);
                 let (size, _align) = crate::unsize::size_and_align_of_dst(fx, layout.ty, info);
                 size
             } else {
@@ -175,7 +175,7 @@ pub fn codegen_intrinsic_call<'a, 'tcx: 'a>(
         min_align_of_val, <T> (c ptr) {
             let layout = fx.layout_of(T);
             let align = if layout.is_unsized() {
-                let (_ptr, info) = ptr.load_value_pair(fx);
+                let (_ptr, info) = ptr.load_scalar_pair(fx);
                 let (_size, align) = crate::unsize::size_and_align_of_dst(fx, layout.ty, info);
                 align
             } else {

src/unsize.rs

@@ -96,7 +96,7 @@ pub fn coerce_unsized_into<'a, 'tcx: 'a>(
         {
             // fat-ptr to fat-ptr unsize preserves the vtable
             // i.e., &'a fmt::Debug+Send => &'a fmt::Debug
-            src.load_value_pair(fx)
+            src.load_scalar_pair(fx)
         } else {
             let base = src.load_scalar(fx);
             unsize_thin_ptr(fx, base, src_ty, dst_ty)

src/vtable.rs

@@ -50,14 +50,7 @@ pub fn get_ptr_and_method_ref<'a, 'tcx: 'a>(
     arg: CValue<'tcx>,
     idx: usize,
 ) -> (Value, Value) {
-    let arg = if arg.layout().ty.is_box() {
-        // Cast `Box<T>` to `*mut T` so `load_value_pair` works
-        arg.unchecked_cast_to(fx.layout_of(fx.tcx.mk_mut_ptr(arg.layout().ty.boxed_ty())))
-    } else {
-        arg
-    };
-
-    let (ptr, vtable) = arg.load_value_pair(fx);
+    let (ptr, vtable) = arg.load_scalar_pair(fx);
     let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes();
     let func_ref = fx.bcx.ins().load(
         pointer_ty(fx.tcx),

test.sh

@@ -17,6 +17,10 @@ echo "[AOT] mini_core_hello_world"
 $RUSTC example/mini_core_hello_world.rs --crate-name mini_core_hello_world --crate-type bin
 ./target/out/mini_core_hello_world abc bcd
 
+echo "[AOT] arbitrary_self_types_pointers_and_wrappers"
+$RUSTC example/arbitrary_self_types_pointers_and_wrappers.rs --crate-name arbitrary_self_types_pointers_and_wrappers --crate-type bin
+./target/out/arbitrary_self_types_pointers_and_wrappers
+
 echo "[BUILD] sysroot"
 time ./build_sysroot/build_sysroot.sh