From e47d063efc7090e4e74282ba4e9f7deb283a1cfd Mon Sep 17 00:00:00 2001
From: pca006132 <jl@m-labs.hk>
Date: Thu, 19 Aug 2021 17:14:38 +0800
Subject: [PATCH] codegen: store to list element

---
 nac3core/src/codegen/expr.rs |  5 ++---
 nac3core/src/codegen/stmt.rs | 21 +++++++++++++++++++--
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/nac3core/src/codegen/expr.rs b/nac3core/src/codegen/expr.rs
index 1c989e693..04790e421 100644
--- a/nac3core/src/codegen/expr.rs
+++ b/nac3core/src/codegen/expr.rs
@@ -14,7 +14,7 @@ use inkwell::{
 use itertools::{chain, izip, zip, Itertools};
 use rustpython_parser::ast::{self, Boolop, Constant, Expr, ExprKind, Operator};
 
-fn assert_int_val<'ctx>(val: BasicValueEnum<'ctx>) -> IntValue<'ctx> {
+pub fn assert_int_val<'ctx>(val: BasicValueEnum<'ctx>) -> IntValue<'ctx> {
     if let BasicValueEnum::IntValue(v) = val {
         v
     } else {
@@ -22,7 +22,7 @@ fn assert_int_val<'ctx>(val: BasicValueEnum<'ctx>) -> IntValue<'ctx> {
     }
 }
 
-fn assert_pointer_val<'ctx>(val: BasicValueEnum<'ctx>) -> PointerValue<'ctx> {
+pub fn assert_pointer_val<'ctx>(val: BasicValueEnum<'ctx>) -> PointerValue<'ctx> {
     if let BasicValueEnum::PointerValue(v) = val {
         v
     } else {
@@ -556,7 +556,6 @@ impl<'ctx, 'a> CodeGenContext<'ctx, 'a> {
                             let arr_ptr =
                                 assert_pointer_val(self.builder.build_load(ptr_to_arr, "loadptr"));
                             let ptr = self.builder.build_gep(arr_ptr, &[index], "loadarrgep");
-                            println!("building element pointer");
                             self.builder.build_load(ptr, "loadarr")
                         }
                     }
diff --git a/nac3core/src/codegen/stmt.rs b/nac3core/src/codegen/stmt.rs
index 6c920ba68..66209b931 100644
--- a/nac3core/src/codegen/stmt.rs
+++ b/nac3core/src/codegen/stmt.rs
@@ -1,4 +1,7 @@
-use super::CodeGenContext;
+use super::{
+    expr::{assert_int_val, assert_pointer_val},
+    CodeGenContext,
+};
 use crate::typecheck::typedef::Type;
 use inkwell::values::{BasicValue, BasicValueEnum, PointerValue};
 use rustpython_parser::ast::{Expr, ExprKind, Stmt, StmtKind};
@@ -45,7 +48,21 @@ impl<'ctx, 'a> CodeGenContext<'ctx, 'a> {
                     )
                 }
             }
-            ExprKind::Subscript { .. } => unimplemented!(),
+            ExprKind::Subscript { value, slice, .. } => {
+                let i32_type = self.ctx.i32_type();
+                let v = assert_pointer_val(self.gen_expr(value).unwrap());
+                let index = assert_int_val(self.gen_expr(slice).unwrap());
+                unsafe {
+                    let ptr_to_arr = self.builder.build_in_bounds_gep(
+                        v,
+                        &[i32_type.const_zero(), i32_type.const_int(1, false)],
+                        "ptr_to_arr",
+                    );
+                    let arr_ptr =
+                        assert_pointer_val(self.builder.build_load(ptr_to_arr, "loadptr"));
+                    self.builder.build_gep(arr_ptr, &[index], "loadarrgep")
+                }
+            }
             _ => unreachable!(),
         }
     }