From 5aa29c4e8be4c7d7a4f6c4c56c6891dd662ea698 Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Tue, 15 Nov 2022 22:02:11 +0100
Subject: [PATCH] morphic + reset/reuse

---
 crates/compiler/alias_analysis/src/lib.rs  | 29 +++++++++++++++++++---
 crates/compiler/gen_llvm/src/llvm/build.rs | 17 +++++++++++--
 2 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/crates/compiler/alias_analysis/src/lib.rs b/crates/compiler/alias_analysis/src/lib.rs
index 01d9287320..d3f91bb538 100644
--- a/crates/compiler/alias_analysis/src/lib.rs
+++ b/crates/compiler/alias_analysis/src/lib.rs
@@ -1543,11 +1543,32 @@ fn expr_spec<'a>(
             }
             _ => unreachable!("empty array does not have a list layout"),
         },
-        Reset { symbol, .. } => {
-            let type_id = layout_spec(env, builder, interner, layout, &WhenRecursive::Unreachable)?;
-            let value_id = env.symbols[symbol];
+        Reset {
+            symbol,
+            update_mode,
+        } => {
+            let tag_value_id = env.symbols[symbol];
 
-            builder.add_unknown_with(block, &[value_id], type_id)
+            let union_layout = match layout {
+                Layout::Union(ul) => ul,
+                _ => unreachable!(),
+            };
+
+            let type_name_bytes = recursive_tag_union_name_bytes(union_layout).as_bytes();
+            let type_name = TypeName(&type_name_bytes);
+
+            // unwrap the named wrapper
+            let union_id = builder.add_unwrap_named(block, MOD_APP, type_name, tag_value_id)?;
+
+            let heap_cell = builder.add_get_tuple_field(block, union_id, TAG_CELL_INDEX)?;
+            let union_data = builder.add_get_tuple_field(block, union_id, TAG_DATA_INDEX)?;
+
+            let mode = update_mode.to_bytes();
+            let update_mode_var = UpdateModeVar(&mode);
+
+            let _unit = builder.add_update(block, update_mode_var, heap_cell)?;
+
+            with_new_heap_cell(builder, block, union_data)
         }
         RuntimeErrorFunction(_) => {
             let type_id = layout_spec(env, builder, interner, layout, &WhenRecursive::Unreachable)?;
diff --git a/crates/compiler/gen_llvm/src/llvm/build.rs b/crates/compiler/gen_llvm/src/llvm/build.rs
index 5335c0dbb3..bb2b0ec22d 100644
--- a/crates/compiler/gen_llvm/src/llvm/build.rs
+++ b/crates/compiler/gen_llvm/src/llvm/build.rs
@@ -1053,7 +1053,16 @@ pub fn build_exp_expr<'a, 'ctx, 'env>(
             load_roc_value(env, *layout, value.into_pointer_value(), "load_boxed_value")
         }
 
-        Reset { symbol, .. } => {
+        Reset {
+            symbol,
+            update_mode,
+        } => {
+            let bytes = update_mode.to_bytes();
+            let update_var = UpdateModeVar(&bytes);
+            let update_mode = func_spec_solutions
+                .update_mode(update_var)
+                .unwrap_or(UpdateMode::Immutable);
+
             let (tag_ptr, layout) = load_symbol_and_layout(scope, symbol);
             let tag_ptr = tag_ptr.into_pointer_value();
 
@@ -1070,7 +1079,11 @@ pub fn build_exp_expr<'a, 'ctx, 'env>(
 
             let refcount_ptr =
                 PointerToRefcount::from_ptr_to_data(env, tag_pointer_clear_tag_id(env, tag_ptr));
-            let is_unique = refcount_ptr.is_1(env);
+
+            let is_unique = match update_mode {
+                UpdateMode::InPlace => env.context.bool_type().const_int(1, false),
+                UpdateMode::Immutable => refcount_ptr.is_1(env),
+            };
 
             env.builder
                 .build_conditional_branch(is_unique, then_block, else_block);