From bade5dd48d135f0177d68ffbce1363bf1f15c776 Mon Sep 17 00:00:00 2001
From: Chadtech <chadtech0@gmail.com>
Date: Mon, 18 Jan 2021 15:26:21 -0500
Subject: [PATCH] Dictionary rust modules

---
 compiler/gen/src/llvm/build_dict.rs | 47 +++++++++++++++++++++++++++++
 compiler/gen/tests/gen_dict.rs      | 29 ++++++++++++++++++
 2 files changed, 76 insertions(+)
 create mode 100644 compiler/gen/src/llvm/build_dict.rs
 create mode 100644 compiler/gen/tests/gen_dict.rs

diff --git a/compiler/gen/src/llvm/build_dict.rs b/compiler/gen/src/llvm/build_dict.rs
new file mode 100644
index 0000000000..d4a08c7069
--- /dev/null
+++ b/compiler/gen/src/llvm/build_dict.rs
@@ -0,0 +1,47 @@
+use crate::llvm::build::{call_bitcode_fn, load_symbol_and_layout, ptr_from_symbol, Env, Scope};
+use inkwell::values::{BasicValueEnum, IntValue};
+use inkwell::AddressSpace;
+use roc_builtins::bitcode;
+use roc_module::symbol::Symbol;
+use roc_mono::layout::{Builtin, Layout};
+
+pub fn dict_size<'a, 'ctx, 'env>(
+    env: &Env<'a, 'ctx, 'env>,
+    scope: &Scope<'a, 'ctx>,
+    dict_symbol: Symbol,
+) -> BasicValueEnum<'ctx> {
+    let ctx = env.context;
+
+    let (_, dict_layout) = load_symbol_and_layout(env, scope, &dict_symbol);
+
+    match dict_layout {
+        Layout::Builtin(Builtin::Dict(_, _)) => {
+            let dict_as_int = dict_symbol_to_i128(env, scope, dict_symbol);
+
+            call_bitcode_fn(env, &[dict_as_int.into()], &bitcode::DICT_SIZE)
+        }
+        Layout::Builtin(Builtin::EmptyDict) => ctx.i64_type().const_zero().into(),
+        _ => unreachable!("Invalid layout given to Dict.size : {:?}", dict_layout),
+    }
+}
+
+fn dict_symbol_to_i128<'a, 'ctx, 'env>(
+    env: &Env<'a, 'ctx, 'env>,
+    scope: &Scope<'a, 'ctx>,
+    symbol: Symbol,
+) -> IntValue<'ctx> {
+    let str_ptr = ptr_from_symbol(scope, symbol);
+
+    let i128_ptr = env
+        .builder
+        .build_bitcast(
+            *str_ptr,
+            env.context.i128_type().ptr_type(AddressSpace::Generic),
+            "cast",
+        )
+        .into_pointer_value();
+
+    env.builder
+        .build_load(i128_ptr, "load_as_i128")
+        .into_int_value()
+}
diff --git a/compiler/gen/tests/gen_dict.rs b/compiler/gen/tests/gen_dict.rs
new file mode 100644
index 0000000000..307dad1646
--- /dev/null
+++ b/compiler/gen/tests/gen_dict.rs
@@ -0,0 +1,29 @@
+#[macro_use]
+extern crate pretty_assertions;
+#[macro_use]
+extern crate indoc;
+
+extern crate bumpalo;
+extern crate inkwell;
+extern crate libc;
+extern crate roc_gen;
+
+#[macro_use]
+mod helpers;
+
+#[cfg(test)]
+mod gen_hash {
+
+    #[test]
+    fn dict_empty_len() {
+        assert_evals_to!(
+            indoc!(
+                r#"
+                    Dict.size Dict.empty
+                "#
+            ),
+            1,
+            usize
+        );
+    }
+}