add pointer Layout

compiler/gen/src/crane/convert.rs

@@ -10,7 +10,7 @@ pub fn type_from_layout(cfg: TargetFrontendConfig, layout: &Layout<'_>) -> Type
     use roc_mono::layout::Layout::*;
 
     match layout {
-        FunctionPointer(_, _) | Struct(_) | Union(_) => cfg.pointer_type(),
+        FunctionPointer(_, _) | Pointer(_) | Struct(_) | Union(_) => cfg.pointer_type(),
         Builtin(builtin) => match builtin {
             Int64 => types::I64,
             Float64 => types::F64,

compiler/gen/src/llvm/convert.rs

@@ -59,6 +59,9 @@ pub fn basic_type_from_layout<'ctx>(
 
             ptr_type.as_basic_type_enum()
         }
+        Pointer(layout) => basic_type_from_layout(arena, context, &layout, ptr_bytes)
+            .ptr_type(AddressSpace::Generic)
+            .into(),
         Struct(sorted_fields) => {
             // Determine types
             let mut field_types = Vec::with_capacity_in(sorted_fields.len(), arena);

compiler/mono/src/layout.rs

@@ -13,6 +13,7 @@ pub enum Layout<'a> {
     Union(&'a [&'a [Layout<'a>]]),
     /// A function. The types of its arguments, then the type of its return value.
     FunctionPointer(&'a [Layout<'a>], &'a Layout<'a>),
+    Pointer(&'a Layout<'a>),
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
@@ -93,6 +94,10 @@ impl<'a> Layout<'a> {
                 // Function pointers are immutable and can always be safely copied
                 true
             }
+            Pointer(_) => {
+                // TODO is this accurate?
+                true
+            }
         }
     }
 
@@ -121,6 +126,7 @@ impl<'a> Layout<'a> {
                 .max()
                 .unwrap_or_default(),
             FunctionPointer(_, _) => pointer_size,
+            Pointer(_) => pointer_size,
         }
     }
 }