store the start of the value for each variable in a table

crates/compiler/gen_llvm/src/llvm/expect.rs

@@ -110,7 +110,21 @@ pub(crate) fn clone_to_shared_memory<'a, 'ctx, 'env>(
 
     offset = write_header(env, original_ptr, offset, condition, region);
 
+    let after_header = offset;
+
+    let space_for_offsets = env
+        .ptr_int()
+        .const_int((lookups.len() * env.target_info.ptr_size()) as _, false);
+
+    let mut lookup_starts = bumpalo::collections::Vec::with_capacity_in(lookups.len(), env.arena);
+
+    offset = env
+        .builder
+        .build_int_add(offset, space_for_offsets, "offset");
+
     for lookup in lookups.iter() {
+        lookup_starts.push(offset);
+
         let (value, layout) = load_symbol_and_layout(scope, lookup);
 
         offset = build_clone(
@@ -124,6 +138,20 @@ pub(crate) fn clone_to_shared_memory<'a, 'ctx, 'env>(
         );
     }
 
+    {
+        let mut offset = after_header;
+
+        for lookup_start in lookup_starts {
+            build_copy(env, original_ptr, offset, lookup_start.into());
+
+            let ptr_width = env
+                .ptr_int()
+                .const_int(env.target_info.ptr_size() as _, false);
+
+            offset = env.builder.build_int_add(offset, ptr_width, "offset")
+        }
+    }
+
     let one = env.ptr_int().const_int(1, false);
     let new_count = env.builder.build_int_add(count, one, "inc");
     write_state(env, original_ptr, new_count, offset)

crates/repl_expect/src/lib.rs

@@ -6,7 +6,10 @@ use roc_mono::{
     layout::{CapturesNiche, LayoutCache},
 };
 use roc_parse::ast::Expr;
-use roc_repl_eval::eval::{jit_to_ast, ToAstProblem};
+use roc_repl_eval::{
+    eval::{jit_to_ast, ToAstProblem},
+    ReplAppMemory,
+};
 use roc_target::TargetInfo;
 use roc_types::subs::{Subs, Variable};
 
@@ -39,7 +42,10 @@ pub fn get_values<'a>(
 
     let app = arena.alloc(app);
 
-    for variable in variables {
+    for (i, variable) in variables.iter().enumerate() {
+        let start = app.memory.deref_usize(start_offset + i * 8);
+        app.offset = start;
+
         let expr = {
             let variable = *variable;