llvm bindings

map the lowlevel op into LLVM code; it calls zig code, but the zig code does not do anything yet

compiler/builtins/bitcode/src/list.zig

@@ -152,6 +152,10 @@ pub fn listMapWithIndex(list: RocList, transform: Opaque, caller: Caller2, align
     }
 }
 
+pub fn listMap2(list: RocList, transform: Opaque, caller: Caller1, alignment: usize, old_element_width: usize, new_element_width: usize) callconv(.C) RocList {
+    unreachable;
+}
+
 pub fn listKeepIf(list: RocList, transform: Opaque, caller: Caller1, alignment: usize, element_width: usize, inc: Inc, dec: Dec) callconv(.C) RocList {
     if (list.bytes) |source_ptr| {
         const size = list.len();

compiler/builtins/bitcode/src/main.zig

@@ -7,6 +7,7 @@ const list = @import("list.zig");
 
 comptime {
     exportListFn(list.listMap, "map");
+    exportListFn(list.listMap2, "map2");
     exportListFn(list.listMapWithIndex, "map_with_index");
     exportListFn(list.listKeepIf, "keep_if");
     exportListFn(list.listWalk, "walk");

compiler/builtins/src/bitcode.rs

@@ -63,6 +63,7 @@ pub const DICT_WALK: &str = "roc_builtins.dict.walk";
 pub const SET_FROM_LIST: &str = "roc_builtins.dict.set_from_list";
 
 pub const LIST_MAP: &str = "roc_builtins.list.map";
+pub const LIST_MAP2: &str = "roc_builtins.list.map2";
 pub const LIST_MAP_WITH_INDEX: &str = "roc_builtins.list.map_with_index";
 pub const LIST_KEEP_IF: &str = "roc_builtins.list.keep_if";
 pub const LIST_KEEP_OKS: &str = "roc_builtins.list.keep_oks";

compiler/gen/src/llvm/build.rs

@@ -7,8 +7,8 @@ use crate::llvm::build_hash::generic_hash;
 use crate::llvm::build_list::{
     allocate_list, empty_list, empty_polymorphic_list, list_append, list_concat, list_contains,
     list_get_unsafe, list_join, list_keep_errs, list_keep_if, list_keep_oks, list_len, list_map,
-    list_map_with_index, list_prepend, list_repeat, list_reverse, list_set, list_single, list_sum,
-    list_walk, list_walk_backwards,
+    list_map2, list_map_with_index, list_prepend, list_repeat, list_reverse, list_set, list_single,
+    list_sum, list_walk, list_walk_backwards,
 };
 use crate::llvm::build_str::{
     str_concat, str_count_graphemes, str_ends_with, str_from_float, str_from_int, str_from_utf8,
@@ -3719,6 +3719,33 @@ fn run_low_level<'a, 'ctx, 'env>(
                 _ => unreachable!("invalid list layout"),
             }
         }
+        ListMap2 => {
+            debug_assert_eq!(args.len(), 3);
+
+            let (list1, list1_layout) = load_symbol_and_layout(scope, &args[0]);
+            let (list2, list2_layout) = load_symbol_and_layout(scope, &args[1]);
+
+            let (func, func_layout) = load_symbol_and_layout(scope, &args[2]);
+
+            match (list1_layout, list2_layout) {
+                (
+                    Layout::Builtin(Builtin::List(_, element1_layout)),
+                    Layout::Builtin(Builtin::List(_, element2_layout)),
+                ) => list_map2(
+                    env,
+                    layout_ids,
+                    func,
+                    func_layout,
+                    list1,
+                    list2,
+                    element1_layout,
+                    element2_layout,
+                ),
+                (Layout::Builtin(Builtin::EmptyList), _)
+                | (_, Layout::Builtin(Builtin::EmptyList)) => empty_list(env),
+                _ => unreachable!("invalid list layout"),
+            }
+        }
         ListMapWithIndex => {
             // List.map : List before, (before -> after) -> List after
             debug_assert_eq!(args.len(), 2);

compiler/gen/src/llvm/build_list.rs

@@ -1230,6 +1230,93 @@ fn list_map_generic<'a, 'ctx, 'env>(
     )
 }
 
+pub fn list_map2<'a, 'ctx, 'env>(
+    env: &Env<'a, 'ctx, 'env>,
+    layout_ids: &mut LayoutIds<'a>,
+    transform: BasicValueEnum<'ctx>,
+    transform_layout: &Layout<'a>,
+    list1: BasicValueEnum<'ctx>,
+    list2: BasicValueEnum<'ctx>,
+    element1_layout: &Layout<'a>,
+    element2_layout: &Layout<'a>,
+) -> BasicValueEnum<'ctx> {
+    let builder = env.builder;
+
+    let return_layout = match transform_layout {
+        Layout::FunctionPointer(_, ret) => ret,
+        Layout::Closure(_, _, ret) => ret,
+        _ => unreachable!("not a callable layout"),
+    };
+
+    let u8_ptr = env.context.i8_type().ptr_type(AddressSpace::Generic);
+
+    let list1_i128 = complex_bitcast(
+        env.builder,
+        list1,
+        env.context.i128_type().into(),
+        "to_i128",
+    );
+
+    let list2_i128 = complex_bitcast(
+        env.builder,
+        list2,
+        env.context.i128_type().into(),
+        "to_i128",
+    );
+
+    let transform_ptr = builder.build_alloca(transform.get_type(), "transform_ptr");
+    env.builder.build_store(transform_ptr, transform);
+
+    let argument_layouts = [element1_layout.clone(), element2_layout.clone()];
+    let stepper_caller =
+        build_transform_caller(env, layout_ids, transform_layout, &argument_layouts)
+            .as_global_value()
+            .as_pointer_value();
+
+    let a_width = env
+        .ptr_int()
+        .const_int(element1_layout.stack_size(env.ptr_bytes) as u64, false);
+
+    let b_width = env
+        .ptr_int()
+        .const_int(element2_layout.stack_size(env.ptr_bytes) as u64, false);
+
+    let c_width = env
+        .ptr_int()
+        .const_int(return_layout.stack_size(env.ptr_bytes) as u64, false);
+
+    let alignment = return_layout.alignment_bytes(env.ptr_bytes);
+    let alignment_iv = env.ptr_int().const_int(alignment as u64, false);
+
+    let dec_a = build_dec_wrapper(env, layout_ids, element1_layout);
+    let dec_b = build_dec_wrapper(env, layout_ids, element2_layout);
+
+    let output = call_bitcode_fn(
+        env,
+        &[
+            list1_i128,
+            list2_i128,
+            env.builder
+                .build_bitcast(transform_ptr, u8_ptr, "to_opaque"),
+            stepper_caller.into(),
+            alignment_iv.into(),
+            a_width.into(),
+            b_width.into(),
+            c_width.into(),
+            dec_a.as_global_value().as_pointer_value().into(),
+            dec_b.as_global_value().as_pointer_value().into(),
+        ],
+        bitcode::LIST_MAP2,
+    );
+
+    complex_bitcast(
+        env.builder,
+        output,
+        collection(env.context, env.ptr_bytes).into(),
+        "from_i128",
+    )
+}
+
 /// List.concat : List elem, List elem -> List elem
 pub fn list_concat<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,