diff --git a/nac3artiq/src/codegen.rs b/nac3artiq/src/codegen.rs
index cc3950be..4f16acf9 100644
--- a/nac3artiq/src/codegen.rs
+++ b/nac3artiq/src/codegen.rs
@@ -2,7 +2,7 @@ use nac3core::{
     codegen::{
         classes::{
             ArrayLikeIndexer, ArrayLikeValue, ArraySliceValue, ListValue, NDArrayType,
-            NDArrayValue, RangeValue, UntypedArrayLikeAccessor,
+            NDArrayValue, ProxyType, ProxyValue, RangeValue, UntypedArrayLikeAccessor,
         },
         expr::{destructure_range, gen_call},
         irrt::call_ndarray_calc_size,
@@ -40,7 +40,6 @@ use std::{
     mem,
     sync::Arc,
 };
-use nac3core::codegen::classes::ProxyType;
 
 /// The parallelism mode within a block.
 #[derive(Copy, Clone, Eq, PartialEq)]
@@ -487,13 +486,10 @@ fn format_rpc_arg<'ctx>(
             let buffer = ctx.builder.build_array_alloca(llvm_i8, buffer_size, "rpc.arg").unwrap();
             let buffer = ArraySliceValue::from_ptr_val(buffer, buffer_size, Some("rpc.arg"));
 
-            let ppdata = generator.gen_var_alloc(ctx, llvm_arg_ty.element_type(), None).unwrap();
-            ctx.builder.build_store(ppdata, llvm_arg.data().base_ptr(ctx, generator)).unwrap();
-
             call_memcpy_generic(
                 ctx,
                 buffer.base_ptr(ctx, generator),
-                ppdata,
+                llvm_arg.ptr_to_data(ctx),
                 llvm_pdata_sizeof,
                 llvm_i1.const_zero(),
             );
@@ -548,6 +544,7 @@ fn format_rpc_ret<'ctx>(
     let llvm_i8 = ctx.ctx.i8_type();
     let llvm_i32 = ctx.ctx.i32_type();
     let llvm_pi8 = llvm_i8.ptr_type(AddressSpace::default());
+    let llvm_ppi8 = llvm_pi8.ptr_type(AddressSpace::default());
 
     let rpc_recv = ctx.module.get_function("rpc_recv").unwrap_or_else(|| {
         ctx.module.add_function("rpc_recv", llvm_i32.fn_type(&[llvm_pi8.into()], false), None)
@@ -572,8 +569,20 @@ fn format_rpc_ret<'ctx>(
             let llvm_usize = generator.get_size_type(ctx.ctx);
 
             let (elem_ty, ndims) = unpack_ndarray_var_tys(&mut ctx.unifier, ret_ty);
-            let llvm_ret_ty =
-                NDArrayType::new(generator, ctx.ctx, ctx.get_llvm_type(generator, elem_ty));
+            let llvm_elem_ty = ctx.get_llvm_type(generator, elem_ty);
+            let llvm_ret_ty = NDArrayType::new(generator, ctx.ctx, llvm_elem_ty);
+            let ndarray = llvm_ret_ty.new_value(generator, ctx, Some("rpc.result"));
+
+            let ndims =
+                if let TypeEnum::TLiteral { values, .. } = &*ctx.unifier.get_ty_immutable(ndims) {
+                    assert_eq!(values.len(), 1);
+
+                    u64::try_from(values[0].clone()).unwrap()
+                } else {
+                    unreachable!();
+                };
+            ndarray.store_ndims(ctx, generator, llvm_usize.const_int(ndims, false));
+            ndarray.create_dim_sizes(ctx, llvm_usize, ndarray.load_ndims(ctx));
 
             let llvm_usize_sizeof = ctx
                 .builder
@@ -582,93 +591,124 @@ fn format_rpc_ret<'ctx>(
             let llvm_pdata_sizeof = ctx
                 .builder
                 .build_int_truncate_or_bit_cast(
-                    llvm_ret_ty.element_type().ptr_type(AddressSpace::default()).size_of(),
+                    llvm_ret_ty.element_type().size_of().unwrap(),
                     llvm_usize,
                     "",
                 )
                 .unwrap();
 
-            let slot_addr = ctx.builder.build_alloca(llvm_ret_ty.as_base_type(), "rpc.ret.slot.addr").unwrap();
-            let slot = ctx.builder.build_load(slot_addr, "rpc.ret.slot").map(BasicValueEnum::into_pointer_value).unwrap();
-            let llvm_ndarray = NDArrayValue::from_ptr_val(slot, llvm_usize, None);
-
-            let ndims = if let TypeEnum::TLiteral { values, .. } = &*ctx.unifier.get_ty_immutable(ndims) {
-                assert_eq!(values.len(), 1);
-
-                u64::try_from(values[0].clone()).unwrap()
-            } else {
-                unreachable!();
-            };
-            llvm_ndarray.store_ndims(ctx, generator, llvm_usize.const_int(ndims, false));
-            llvm_ndarray.create_dim_sizes(ctx, llvm_usize, llvm_ndarray.load_ndims(ctx));
-
             let dims_buf_sz =
-                ctx.builder.build_int_mul(llvm_ndarray.load_ndims(ctx), llvm_usize_sizeof, "").unwrap();
+                ctx.builder.build_int_mul(ndarray.load_ndims(ctx), llvm_usize_sizeof, "").unwrap();
 
             let buffer_size =
                 ctx.builder.build_int_add(dims_buf_sz, llvm_pdata_sizeof, "").unwrap();
 
-            let buffer = ctx.builder.build_array_alloca(llvm_i8, buffer_size, "rpc.buffer").unwrap();
-            let buffer = ArraySliceValue::from_ptr_val(buffer, buffer_size, Some("rpc.buffer"));
-
-            // recv [*data, dim_sz[..]]
-            let alloc_size = ctx
-                .build_call_or_invoke(rpc_recv, &[buffer.base_ptr(ctx, generator).into()], "rpc.size.next")
-                .map(BasicValueEnum::into_int_value)
-                .unwrap();
-
-            let ppdata = generator.gen_var_alloc(ctx, llvm_ret_ty.element_type(), None).unwrap();
-            ctx.builder.build_store(ppdata, llvm_ndarray.data().base_ptr(ctx, generator)).unwrap();
-            call_memcpy_generic(
-                ctx,
-                ppdata,
-                buffer.base_ptr(ctx, generator),
-                llvm_pdata_sizeof,
-                llvm_i1.const_zero(),
-            );
-
-            let pbuffer_dims_begin =
-                unsafe { buffer.ptr_offset_unchecked(ctx, generator, &llvm_pdata_sizeof, None) };
-            call_memcpy_generic(
-                ctx,
-                llvm_ndarray.dim_sizes().base_ptr(ctx, generator),
-                pbuffer_dims_begin,
-                dims_buf_sz,
-                llvm_i1.const_zero(),
-            );
-
-            let is_done = ctx
+            let buffer =
+                ctx.builder.build_array_alloca(llvm_pi8, buffer_size, "rpc.buffer").unwrap();
+            let buffer = ctx
                 .builder
-                .build_int_compare(IntPredicate::EQ, llvm_i32.const_zero(), alloc_size, "rpc.done")
+                .build_bitcast(buffer, llvm_pi8, "")
+                .map(BasicValueEnum::into_pointer_value)
                 .unwrap();
+            let buffer = ArraySliceValue::from_ptr_val(
+                buffer,
+                ctx.builder
+                    .build_left_shift(buffer_size, llvm_usize.const_int(2, false), "")
+                    .unwrap(),
+                Some("rpc.buffer.ptr"),
+            );
 
-            let alloc_ptr = ctx.builder.build_array_alloca(llvm_pi8, alloc_size, "rpc.alloc").unwrap();
-            let alloc_ptr = ctx.builder.build_bitcast(alloc_ptr, llvm_pi8, "rpc.alloc.ptr").map(BasicValueEnum::into_pointer_value).unwrap();
-
-            ctx.builder.build_conditional_branch(is_done, tail_bb, head_bb).unwrap();
+            let i_addr = ctx.builder.build_alloca(llvm_usize, "i.addr").unwrap();
+            ctx.builder.build_store(i_addr, llvm_usize.const_zero()).unwrap();
+            ctx.builder.build_unconditional_branch(head_bb).unwrap();
 
             ctx.builder.position_at_end(head_bb);
             let phi = ctx.builder.build_phi(llvm_pi8, "rpc.ptr").unwrap();
-            phi.add_incoming(&[(&alloc_ptr, prehead_bb)]);
+            phi.add_incoming(&[(&buffer.base_ptr(ctx, generator), prehead_bb)]);
             let alloc_size = ctx
                 .build_call_or_invoke(rpc_recv, &[phi.as_basic_value()], "rpc.size.next")
-                .unwrap()
-                .into_int_value();
+                .map(BasicValueEnum::into_int_value)
+                .unwrap();
+
+            // Parse metadata block for ndarrays
+            gen_if_callback(
+                generator,
+                ctx,
+                |_, ctx| {
+                    let i = ctx
+                        .builder
+                        .build_load(i_addr, "")
+                        .map(BasicValueEnum::into_int_value)
+                        .unwrap();
+
+                    Ok(ctx
+                        .builder
+                        .build_int_compare(IntPredicate::EQ, i, llvm_usize.const_zero(), "")
+                        .unwrap())
+                },
+                |generator, ctx| {
+                    let data_addr = phi.as_basic_value().into_pointer_value();
+                    let data_addr = ctx
+                        .builder
+                        .build_load(
+                            ctx.builder
+                                .build_bitcast(data_addr, llvm_ppi8, "")
+                                .map(BasicValueEnum::into_pointer_value)
+                                .unwrap(),
+                            "",
+                        )
+                        .map(BasicValueEnum::into_pointer_value)
+                        .unwrap();
+
+                    call_memcpy_generic(
+                        ctx,
+                        ndarray.ptr_to_data(ctx),
+                        data_addr,
+                        llvm_pdata_sizeof,
+                        llvm_i1.const_zero(),
+                    );
+
+                    let pbuffer_dims_begin = unsafe {
+                        buffer.ptr_offset_unchecked(ctx, generator, &llvm_pdata_sizeof, None)
+                    };
+                    call_memcpy_generic(
+                        ctx,
+                        ndarray.dim_sizes().base_ptr(ctx, generator),
+                        pbuffer_dims_begin,
+                        dims_buf_sz,
+                        llvm_i1.const_zero(),
+                    );
+
+                    Ok(())
+                },
+                |_, _| Ok(()),
+            )
+            .unwrap();
+
             let is_done = ctx
                 .builder
                 .build_int_compare(IntPredicate::EQ, llvm_i32.const_zero(), alloc_size, "rpc.done")
                 .unwrap();
-            ctx.builder.build_conditional_branch(is_done, tail_bb, alloc_bb).unwrap();
 
+            ctx.builder.build_conditional_branch(is_done, tail_bb, alloc_bb).unwrap();
             ctx.builder.position_at_end(alloc_bb);
-            let alloc_ptr = ctx.builder.build_array_alloca(llvm_pi8, alloc_size, "rpc.alloc").unwrap();
-            let alloc_ptr = ctx.builder.build_bitcast(alloc_ptr, llvm_pi8, "rpc.alloc.ptr").unwrap();
+
+            let alloc_ptr =
+                ctx.builder.build_array_alloca(llvm_pi8, alloc_size, "rpc.alloc").unwrap();
+            let alloc_ptr = ctx
+                .builder
+                .build_bitcast(alloc_ptr, llvm_pi8, "")
+                .map(BasicValueEnum::into_pointer_value)
+                .unwrap();
             phi.add_incoming(&[(&alloc_ptr, alloc_bb)]);
+            let i =
+                ctx.builder.build_load(i_addr, "i").map(BasicValueEnum::into_int_value).unwrap();
+            let i = ctx.builder.build_int_add(i, llvm_usize.const_int(1, false), "").unwrap();
+            ctx.builder.build_store(i_addr, i).unwrap();
             ctx.builder.build_unconditional_branch(head_bb).unwrap();
 
             ctx.builder.position_at_end(tail_bb);
-
-            ctx.builder.build_load(slot_addr, "rpc.result").unwrap()
+            ndarray.as_base_value().into()
         }
 
         _ => {
@@ -691,8 +731,10 @@ fn format_rpc_ret<'ctx>(
             ctx.builder.build_conditional_branch(is_done, tail_bb, alloc_bb).unwrap();
             ctx.builder.position_at_end(alloc_bb);
 
-            let alloc_ptr = ctx.builder.build_array_alloca(llvm_pi8, alloc_size, "rpc.alloc").unwrap();
-            let alloc_ptr = ctx.builder.build_bitcast(alloc_ptr, llvm_pi8, "rpc.alloc.ptr").unwrap();
+            let alloc_ptr =
+                ctx.builder.build_array_alloca(llvm_pi8, alloc_size, "rpc.alloc").unwrap();
+            let alloc_ptr =
+                ctx.builder.build_bitcast(alloc_ptr, llvm_pi8, "rpc.alloc.ptr").unwrap();
             phi.add_incoming(&[(&alloc_ptr, alloc_bb)]);
             ctx.builder.build_unconditional_branch(head_bb).unwrap();
 
@@ -842,7 +884,7 @@ fn rpc_codegen_callback_fn<'ctx>(
 
     let result = format_rpc_ret(generator, ctx, fun.0.ret);
 
-    if result.is_some_and(|res| !res.get_type().is_pointer_type()) {
+    if !result.is_some_and(|res| res.get_type().is_pointer_type()) {
         call_stackrestore(ctx, stackptr);
     }
 
diff --git a/nac3core/src/codegen/classes.rs b/nac3core/src/codegen/classes.rs
index 52e9cca0..b6d3f2fa 100644
--- a/nac3core/src/codegen/classes.rs
+++ b/nac3core/src/codegen/classes.rs
@@ -1330,7 +1330,7 @@ impl<'ctx> NDArrayValue<'ctx> {
     }
 
     /// Returns the pointer to the field storing the number of dimensions of this `NDArray`.
-    fn ptr_to_ndims(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
+    pub fn ptr_to_ndims(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
         let llvm_i32 = ctx.ctx.i32_type();
         let var_name = self.name.map(|v| format!("{v}.ndims.addr")).unwrap_or_default();
 
@@ -1366,7 +1366,7 @@ impl<'ctx> NDArrayValue<'ctx> {
 
     /// Returns the double-indirection pointer to the `dims` array, as if by calling `getelementptr`
     /// on the field.
-    fn ptr_to_dims(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
+    pub fn ptr_to_dims(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
         let llvm_i32 = ctx.ctx.i32_type();
         let var_name = self.name.map(|v| format!("{v}.dims.addr")).unwrap_or_default();
 
@@ -1404,7 +1404,7 @@ impl<'ctx> NDArrayValue<'ctx> {
 
     /// Returns the double-indirection pointer to the `data` array, as if by calling `getelementptr`
     /// on the field.
-    fn ptr_to_data(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
+    pub fn ptr_to_data(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
         let llvm_i32 = ctx.ctx.i32_type();
         let var_name = self.name.map(|v| format!("{v}.data.addr")).unwrap_or_default();
 
@@ -1420,7 +1420,7 @@ impl<'ctx> NDArrayValue<'ctx> {
     }
 
     /// Stores the array of data elements `data` into this instance.
-    fn store_data(&self, ctx: &CodeGenContext<'ctx, '_>, data: PointerValue<'ctx>) {
+    pub fn store_data(&self, ctx: &CodeGenContext<'ctx, '_>, data: PointerValue<'ctx>) {
         ctx.builder.build_store(self.ptr_to_data(ctx), data).unwrap();
     }