From 2edeb31d21ed3641d6423c88d5a81190436906bd Mon Sep 17 00:00:00 2001
From: ychenfo <yc@m-labs.hk>
Date: Thu, 31 Mar 2022 01:06:11 +0800
Subject: [PATCH] nac3core: do not get llvm value too eagerly for kernel
 invariant

---
 nac3core/src/codegen/expr.rs | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/nac3core/src/codegen/expr.rs b/nac3core/src/codegen/expr.rs
index fa640cb8..33c0eec4 100644
--- a/nac3core/src/codegen/expr.rs
+++ b/nac3core/src/codegen/expr.rs
@@ -1002,21 +1002,22 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
                 let resolver = ctx.resolver.clone();
                 let val = resolver.get_symbol_value(*id, ctx).unwrap();
                 // if is option, need to cast pointer to handle None
-                match (
-                    &*ctx.unifier.get_ty(expr.custom.unwrap()),
-                    val.to_basic_value_enum(ctx, generator)?
-                ) {
-                    (TypeEnum::TObj { obj_id, params, .. }, BasicValueEnum::PointerValue(ptr))
+                match &*ctx.unifier.get_ty(expr.custom.unwrap()) {
+                    TypeEnum::TObj { obj_id, params, .. }
                         if *obj_id == ctx.primitives.option.get_obj_id(&ctx.unifier) =>
                     {
-                        let actual_ptr_ty = ctx.get_llvm_type(
-                            generator,
-                            *params.iter().next().unwrap().1,
-                        )
-                        .ptr_type(AddressSpace::Generic);
-                        ctx.builder.build_bitcast(ptr, actual_ptr_ty, "option_ptr_cast").into()
+                        if let BasicValueEnum::PointerValue(ptr) = val.to_basic_value_enum(ctx, generator)? {
+                            let actual_ptr_ty = ctx.get_llvm_type(
+                                generator,
+                                *params.iter().next().unwrap().1,
+                            )
+                            .ptr_type(AddressSpace::Generic);
+                            ctx.builder.build_bitcast(ptr, actual_ptr_ty, "option_ptr_cast").into()
+                        } else {
+                            unreachable!("option obj must be ptr")
+                        }
                     }
-                    val => val.1.into(),
+                    _ => val,
                 }
             }
         },