artiq: Implement handling for const generic variables

A lot of refactoring was performed, specifically with relaxing
expression codegen to return Option in case where ellipsis are used
within a subexpression.

nac3artiq/src/codegen.rs

@@ -145,7 +145,8 @@ impl<'a> ArtiqCodeGenerator<'a> {
             let end_store = self.gen_store_target(
                 ctx,
                 &end,
-                store_name.map(|name| format!("{name}.addr")).as_deref())?;
+                store_name.map(|name| format!("{name}.addr")).as_deref())?
+                .unwrap();
             ctx.builder.build_store(end_store, max);
         }
 
@@ -261,7 +262,9 @@ impl<'b> CodeGenerator for ArtiqCodeGenerator<'b> {
                                     node: ExprKind::Name { id: start, ctx: name_ctx.clone() },
                                     custom: Some(ctx.primitives.int64),
                                 };
-                                let start = self.gen_store_target(ctx, &start_expr, Some("start.addr"))?;
+                                let start = self
+                                    .gen_store_target(ctx, &start_expr, Some("start.addr"))?
+                                    .unwrap();
                                 ctx.builder.build_store(start, now);
                                 Ok(Some(start_expr)) as Result<_, String>
                             },
@@ -274,7 +277,9 @@ impl<'b> CodeGenerator for ArtiqCodeGenerator<'b> {
                             node: ExprKind::Name { id: end, ctx: name_ctx.clone() },
                             custom: Some(ctx.primitives.int64),
                         };
-                        let end = self.gen_store_target(ctx, &end_expr, Some("end.addr"))?;
+                        let end = self
+                            .gen_store_target(ctx, &end_expr, Some("end.addr"))?
+                            .unwrap();
                         ctx.builder.build_store(end, now);
                         self.end = Some(end_expr);
                         self.name_counter += 1;

nac3core/src/codegen/expr.rs

@@ -265,7 +265,7 @@ impl<'ctx, 'a> CodeGenContext<'ctx, 'a> {
                 }
             }
             Constant::Ellipsis => {
-                let msg = self.gen_string(generator, "");
+                let msg = self.gen_string(generator, "NotImplementedError");
 
                 self.raise_exn(
                     generator,
@@ -967,9 +967,15 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
         ctx.builder.position_at_end(init_bb);
 
         let Comprehension { target, iter, ifs, .. } = &generators[0];
-        let iter_val = match generator.gen_expr(ctx, iter)? {
+        let iter_val = if let Some(v) = generator.gen_expr(ctx, iter)? {
-            Some(v) => v.to_basic_value_enum(ctx, generator, iter.custom.unwrap())?,
+            v.to_basic_value_enum(ctx, generator, iter.custom.unwrap())?
-            None => return Ok(None),
+        } else {
+            for bb in [test_bb, body_bb, cont_bb] {
+                ctx.builder.position_at_end(bb);
+                ctx.builder.build_unreachable();
+            }
+
+            return Ok(None)
         };
         let int32 = ctx.ctx.i32_type();
         let size_t = generator.get_size_type(ctx.ctx);
@@ -1013,9 +1019,7 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
             list_content = ctx.build_gep_and_load(list, &[zero_size_t, zero_32], Some("listcomp.data.addr"))
                 .into_pointer_value();
 
-            let Some(i) = generator.gen_store_target(ctx, target, Some("i.addr"))? else {
+            let i = generator.gen_store_target(ctx, target, Some("i.addr"))?.unwrap();
-                unreachable!()
-            };
             ctx.builder.build_store(i, ctx.builder.build_int_sub(start, step, "start_init"));
 
             ctx.builder.build_conditional_branch(
@@ -1070,12 +1074,24 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
             generator.gen_assign(ctx, target, val.into())?;
         }
 
+        // Emits the content of `cont_bb`
+        let emit_cont_bb = |ctx: &CodeGenContext| {
+            ctx.builder.position_at_end(cont_bb);
+            let len_ptr = unsafe {
+                ctx.builder.build_gep(list, &[zero_size_t, int32.const_int(1, false)], "length")
+            };
+            ctx.builder.build_store(len_ptr, ctx.builder.build_load(index, "index"));
+        };
+
         for cond in ifs.iter() {
-            let result = match generator.gen_expr(ctx, cond)? {
+            let result = if let Some(v) = generator.gen_expr(ctx, cond)? {
-                Some(v) => v
+                v.to_basic_value_enum(ctx, generator, cond.custom.unwrap())?.into_int_value()
-                    .to_basic_value_enum(ctx, generator, cond.custom.unwrap())?
+            } else {
-                    .into_int_value(),
+                // Bail if the predicate is an ellipsis - Emit cont_bb contents in case the
-                None => return Ok(None),
+                // no element matches the predicate
+                emit_cont_bb(ctx);
+
+                return Ok(None)
             };
             let result = generator.bool_to_i1(ctx, result);
             let succ = ctx.ctx.append_basic_block(current, "then");
@@ -1084,9 +1100,11 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
             ctx.builder.position_at_end(succ);
         }
 
-        let elem = match generator.gen_expr(ctx, elt)? {
+        let Some(elem) = generator.gen_expr(ctx, elt)? else {
-            Some(v) => v,
+            // Similarly, bail if the generator expression is an ellipsis, but keep cont_bb contents
-            None => return Ok(None),
+            emit_cont_bb(ctx);
+
+            return Ok(None)
         };
         let i = ctx.builder.build_load(index, "i").into_int_value();
         let elem_ptr = unsafe { ctx.builder.build_gep(list_content, &[i], "elem_ptr") };
@@ -1096,11 +1114,7 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
             .build_store(index, ctx.builder.build_int_add(i, size_t.const_int(1, false), "inc"));
         ctx.builder.build_unconditional_branch(test_bb);
 
-        ctx.builder.position_at_end(cont_bb);
+        emit_cont_bb(ctx);
-        let len_ptr = unsafe {
-            ctx.builder.build_gep(list, &[zero_size_t, int32.const_int(1, false)], "length")
-        };
-        ctx.builder.build_store(len_ptr, ctx.builder.build_load(index, "index"));
 
         Ok(Some(list.into()))
     } else {
@@ -1126,13 +1140,15 @@ pub fn gen_binop_expr<'ctx, 'a, G: CodeGenerator>(
 ) -> Result<Option<ValueEnum<'ctx>>, String> {
     let ty1 = ctx.unifier.get_representative(left.custom.unwrap());
     let ty2 = ctx.unifier.get_representative(right.custom.unwrap());
-    let left_val = match generator.gen_expr(ctx, left)? {
+    let left_val = if let Some(v) = generator.gen_expr(ctx, left)? {
-        Some(v) => v.to_basic_value_enum(ctx, generator, left.custom.unwrap())?,
+        v.to_basic_value_enum(ctx, generator, left.custom.unwrap())?
-        None => return Ok(None),
+    } else {
+        return Ok(None)
     };
-    let right_val = match generator.gen_expr(ctx, right)? {
+    let right_val = if let Some(v) = generator.gen_expr(ctx, right)? {
-        Some(v) => v.to_basic_value_enum(ctx, generator, right.custom.unwrap())?,
+        v.to_basic_value_enum(ctx, generator, right.custom.unwrap())?
-        None => return Ok(None),
+    } else {
+        return Ok(None)
     };
 
     // we can directly compare the types, because we've got their representatives
@@ -1360,11 +1376,10 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
         }
         ExprKind::BoolOp { op, values } => {
             // requires conditional branches for short-circuiting...
-            let left = match generator.gen_expr(ctx, &values[0])? {
+            let left = if let Some(v) = generator.gen_expr(ctx, &values[0])? {
-                Some(v) => v
+                v.to_basic_value_enum(ctx, generator, values[0].custom.unwrap())?.into_int_value()
-                    .to_basic_value_enum(ctx, generator, values[0].custom.unwrap())?
+            } else {
-                    .into_int_value(),
+                return Ok(None)
-                None => return Ok(None),
             };
             let left = generator.bool_to_i1(ctx, left);
             let current = ctx.builder.get_insert_block().unwrap().get_parent().unwrap();
@@ -1377,46 +1392,61 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
                     ctx.builder.position_at_end(a_bb);
                     let a = ctx.ctx.i8_type().const_int(1, false);
                     ctx.builder.build_unconditional_branch(cont_bb);
+
                     ctx.builder.position_at_end(b_bb);
-                    let b = match generator.gen_expr(ctx, &values[1])? {
+                    let b = if let Some(v) = generator.gen_expr(ctx, &values[1])? {
-                        Some(v) =>
+                        let b = v.to_basic_value_enum(ctx, generator, values[1].custom.unwrap())?.into_int_value();
-                            v.to_basic_value_enum(ctx, generator, values[1].custom.unwrap())?
+                        let b = generator.bool_to_i8(ctx, b);
-                            .into_int_value(),
+                        ctx.builder.build_unconditional_branch(cont_bb);
-                        None => return Ok(None),
+
+                        Some(b)
+                    } else {
+                        None
                     };
-                    let b = generator.bool_to_i8(ctx, b);
+
-                    ctx.builder.build_unconditional_branch(cont_bb);
+                    (Some(a), b)
-                    (a, b)
                 }
                 Boolop::And => {
                     ctx.builder.position_at_end(a_bb);
-                    let a = match generator.gen_expr(ctx, &values[1])? {
+                    let a = if let Some(v) = generator.gen_expr(ctx, &values[1])? {
-                        Some(v) => v
+                        let a = v.to_basic_value_enum(ctx, generator, values[1].custom.unwrap())?.into_int_value();
-                            .to_basic_value_enum(ctx, generator, values[1].custom.unwrap())?
+                        let a = generator.bool_to_i8(ctx, a);
-                            .into_int_value(),
+                        ctx.builder.build_unconditional_branch(cont_bb);
-                        None => return Ok(None),
+
+                        Some(a)
+                    } else {
+                        None
                     };
-                    let a = generator.bool_to_i8(ctx, a);
+
-                    ctx.builder.build_unconditional_branch(cont_bb);
                     ctx.builder.position_at_end(b_bb);
                     let b = ctx.ctx.i8_type().const_zero();
                     ctx.builder.build_unconditional_branch(cont_bb);
-                    (a, b)
+
+                    (a, Some(b))
                 }
             };
+
             ctx.builder.position_at_end(cont_bb);
-            let phi = ctx.builder.build_phi(ctx.ctx.i8_type(), "");
+            match (a, b) {
-            phi.add_incoming(&[(&a, a_bb), (&b, b_bb)]);
+                (Some(a), Some(b)) => {
-            phi.as_basic_value().into()
+                    let phi = ctx.builder.build_phi(ctx.ctx.i8_type(), "");
+                    phi.add_incoming(&[(&a, a_bb), (&b, b_bb)]);
+                    phi.as_basic_value().into()
+                }
+                (Some(a), None) => a.into(),
+                (None, Some(b)) => b.into(),
+                (None, None) => unreachable!(),
+            }
         }
         ExprKind::BinOp { op, left, right } => {
             return gen_binop_expr(generator, ctx, left, op, right, expr.location, false);
         }
         ExprKind::UnaryOp { op, operand } => {
             let ty = ctx.unifier.get_representative(operand.custom.unwrap());
-            let val = match generator.gen_expr(ctx, operand)? {
+            let val = if let Some(v) = generator.gen_expr(ctx, operand)? {
-                Some(v) => v.to_basic_value_enum(ctx, generator, operand.custom.unwrap())?,
+                v.to_basic_value_enum(ctx, generator, operand.custom.unwrap())?
-                None => return Ok(None),
+            } else {
+                return Ok(None)
             };
             if ty == ctx.primitives.bool {
                 let val = val.into_int_value();
@@ -1454,7 +1484,7 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
             }
         }
         ExprKind::Compare { left, ops, comparators } => {
-            izip!(chain(once(left.as_ref()), comparators.iter()), comparators.iter(), ops.iter(),)
+            let cmp_val = izip!(chain(once(left.as_ref()), comparators.iter()), comparators.iter(), ops.iter(),)
                 .fold(Ok(None), |prev: Result<Option<_>, String>, (lhs, rhs, op)| {
                     let ty = ctx.unifier.get_representative(lhs.custom.unwrap());
                     let current =
@@ -1529,9 +1559,12 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
                             unimplemented!()
                         };
                     Ok(prev?.map(|v| ctx.builder.build_and(v, current, "cmp")).or(Some(current)))
-                })?
+                })?;
-                .unwrap()
+
-                .into() // as there should be at least 1 element, it should never be none
+                match cmp_val {
+                    Some(v) => v.into(),
+                    None => return Ok(None),
+                }
         }
         ExprKind::IfExp { test, body, orelse } => {
             let test = match generator.gen_expr(ctx, test)? {
@@ -1580,9 +1613,10 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
             }
 
             ctx.builder.position_at_end(cont_bb);
-            match result {
+            if let Some(v) = result {
-                None => return Ok(None),
+                ctx.builder.build_load(v, "if_exp_val_load").into()
-                Some(v) => return Ok(Some(ctx.builder.build_load(v, "if_exp_val_load").into()))
+            } else {
+                return Ok(None)
             }
         }
         ExprKind::Call { func, args, keywords } => {
@@ -1732,11 +1766,10 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
         }
         ExprKind::Subscript { value, slice, .. } => {
             if let TypeEnum::TList { ty } = &*ctx.unifier.get_ty(value.custom.unwrap()) {
-                let v = match generator.gen_expr(ctx, value)? {
+                let v = if let Some(v) = generator.gen_expr(ctx, value)? {
-                    Some(v) => v
+                    v.to_basic_value_enum(ctx, generator, value.custom.unwrap())?.into_pointer_value()
-                        .to_basic_value_enum(ctx, generator, value.custom.unwrap())?
+                } else {
-                        .into_pointer_value(),
+                    return Ok(None)
-                    None => return Ok(None),
                 };
                 let ty = ctx.get_llvm_type(generator, *ty);
                 let arr_ptr = ctx.build_gep_and_load(v, &[zero, zero], Some("arr.addr"))
@@ -1785,11 +1818,10 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
                     let len = ctx
                         .build_gep_and_load(v, &[zero, int32.const_int(1, false)], Some("len"))
                         .into_int_value();
-                    let raw_index = match generator.gen_expr(ctx, slice)? {
+                    let raw_index = if let Some(v) = generator.gen_expr(ctx, slice)? {
-                        Some(v) => v
+                        v.to_basic_value_enum(ctx, generator, slice.custom.unwrap())?.into_int_value()
-                            .to_basic_value_enum(ctx, generator, slice.custom.unwrap())?
+                    } else {
-                            .into_int_value(),
+                        return Ok(None)
-                        None => return Ok(None),
                     };
                     let raw_index = ctx.builder.build_int_s_extend(
                         raw_index,
@@ -1855,10 +1887,13 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
                 unreachable!("should not be other subscriptable types after type check");
             }
         },
-        ExprKind::ListComp { .. } => match gen_comprehension(generator, ctx, expr)? {
+        ExprKind::ListComp { .. } => {
-            Some(v) => v.into(),
+            if let Some(v) = gen_comprehension(generator, ctx, expr)? {
-            None => return Ok(None),
+                v.into()
-        },
+            } else {
+                return Ok(None)
+            }
+        }
         _ => unimplemented!(),
     }))
 }

nac3core/src/codegen/irrt/mod.rs

@@ -166,22 +166,22 @@ pub fn handle_slice_indices<'a, 'ctx, G: CodeGenerator>(
     let length = ctx.builder.build_int_truncate_or_bit_cast(length, int32, "leni32");
     Ok(Some(match (start, end, step) {
         (s, e, None) => (
-            match s.as_ref() {
+            if let Some(s) = s.as_ref() {
-                Some(s) => {
+                match handle_slice_index_bound(s, ctx, generator, length)? {
-                    if let Some(v) = handle_slice_index_bound(s, ctx, generator, length)? {
+                    Some(v) => v,
-                        v
+                    None => return Ok(None),
-                    } else { return Ok(None) }
                 }
-                None => int32.const_zero(),
+            } else {
+                int32.const_zero()
             },
             {
-                let e = match e.as_ref() {
+                let e = if let Some(s) = e.as_ref() {
-                    Some(s) => {
+                    match handle_slice_index_bound(s, ctx, generator, length)? {
-                        if let Some(v) = handle_slice_index_bound(s, ctx, generator, length)? {
+                        Some(v) => v,
-                            v
+                        None => return Ok(None),
-                        } else { return Ok(None) }
                     }
-                    None => length,
+                } else {
+                    length
                 };
                 ctx.builder.build_int_sub(e, one, "final_end")
             },
@@ -190,7 +190,9 @@ pub fn handle_slice_indices<'a, 'ctx, G: CodeGenerator>(
         (s, e, Some(step)) => {
             let step = if let Some(v) = generator.gen_expr(ctx, step)? {
                 v.to_basic_value_enum(ctx, generator, ctx.primitives.int32)?.into_int_value()
-            } else { return Ok(None) };
+            } else {
+                return Ok(None)
+            };
             // assert step != 0, throw exception if not
             let not_zero = ctx.builder.build_int_compare(
                 IntPredicate::NE,
@@ -273,7 +275,9 @@ pub fn handle_slice_index_bound<'a, 'ctx, G: CodeGenerator>(
 
     let i = if let Some(v) = generator.gen_expr(ctx, i)? {
         v.to_basic_value_enum(ctx, generator, i.custom.unwrap())?
-    } else { return Ok(None) };
+    } else {
+        return Ok(None)
+    };
     Ok(Some(ctx
         .builder
         .build_call(func, &[i.into(), length.into()], "bounded_ind")

nac3core/src/codegen/stmt.rs

@@ -109,13 +109,17 @@ pub fn gen_store_target<'ctx, 'a, G: CodeGenerator>(
             let zero = i32_type.const_zero();
             let v = if let Some(v) = generator.gen_expr(ctx, value)? {
                 v.to_basic_value_enum(ctx, generator, value.custom.unwrap())?.into_pointer_value()
-            } else { return Ok(None) };
+            } else {
+                return Ok(None)
+            };
             let len = ctx
                 .build_gep_and_load(v, &[zero, i32_type.const_int(1, false)], Some("len"))
                 .into_int_value();
             let raw_index = if let Some(v) = generator.gen_expr(ctx, slice)? {
                 v.to_basic_value_enum(ctx, generator, slice.custom.unwrap())?.into_int_value()
-            } else { return Ok(None) };
+            } else {
+                return Ok(None)
+            };
             let raw_index = ctx.builder.build_int_s_extend(
                 raw_index,
                 generator.get_size_type(ctx.ctx),
@@ -272,13 +276,14 @@ pub fn gen_for<'ctx, 'a, G: CodeGenerator>(
         // store loop bb information and restore it later
         let loop_bb = ctx.loop_target.replace((incr_bb, cont_bb));
 
-        let iter_val = match generator.gen_expr(ctx, iter)? {
+        let iter_val = if let Some(v) = generator.gen_expr(ctx, iter)? {
-            Some(v) => v.to_basic_value_enum(
+            v.to_basic_value_enum(
                 ctx,
                 generator,
                 iter.custom.unwrap(),
-            )?,
+            )?
-            None => return Ok(()),
+        } else {
+            return Ok(())
         };
         if is_iterable_range_expr {
             let iter_val = iter_val.into_pointer_value();
@@ -421,7 +426,14 @@ pub fn gen_while<'ctx, 'a, G: CodeGenerator>(
         ctx.builder.position_at_end(test_bb);
         let test = if let Some(v) = generator.gen_expr(ctx, test)? {
             v.to_basic_value_enum(ctx, generator, test.custom.unwrap())?
-        } else { return Ok(()) };
+        } else {
+            for bb in [body_bb, cont_bb] {
+                ctx.builder.position_at_end(bb);
+                ctx.builder.build_unreachable();
+            }
+
+            return Ok(())
+        };
         if let BasicValueEnum::IntValue(test) = test {
             ctx.builder.build_conditional_branch(generator.bool_to_i1(ctx, test), body_bb, orelse_bb);
         } else {
@@ -483,14 +495,11 @@ pub fn gen_if<'ctx, 'a, G: CodeGenerator>(
         };
         ctx.builder.build_unconditional_branch(test_bb);
         ctx.builder.position_at_end(test_bb);
-        let test = match generator.gen_expr(ctx, test)? {
+        let test = generator
-            Some(v) => v.to_basic_value_enum(ctx, generator, test.custom.unwrap())?,
+            .gen_expr(ctx, test)
-            None => return Ok(()),
+            .and_then(|v| v.map(|v| v.to_basic_value_enum(ctx, generator, test.custom.unwrap())).transpose())?;
-        };
+        if let Some(BasicValueEnum::IntValue(test)) = test {
-        if let BasicValueEnum::IntValue(test) = test {
             ctx.builder.build_conditional_branch(generator.bool_to_i1(ctx, test), body_bb, orelse_bb);
-        } else {
-            unreachable!()
         };
         ctx.builder.position_at_end(body_bb);
         generator.gen_block(ctx, body.iter())?;
@@ -1043,11 +1052,12 @@ pub fn gen_return<'ctx, 'a, G: CodeGenerator>(
 ) -> Result<(), String> {
     let func = ctx.builder.get_insert_block().and_then(|bb| bb.get_parent()).unwrap();
     let value = if let Some(v_expr) = value.as_ref() {
-        match generator.gen_expr(ctx, v_expr).transpose() {
+        if let Some(v) = generator.gen_expr(ctx, v_expr).transpose() {
-            Some(v) => Some(
+            Some(
                 v.and_then(|v| v.to_basic_value_enum(ctx, generator, v_expr.custom.unwrap()))?
-            ),
+            )
-            None => return Ok(())
+        } else {
+            return Ok(())
         }
     } else {
         None

nac3standalone/demo/src/ellipsis.py

@@ -1,7 +0,0 @@
-@extern
-def output_str(x: str):
-    ...
-
-def run() -> int32:
-    [i for i in range(10) if ...]
-    return 0

nac3standalone/src/main.rs

@@ -76,7 +76,7 @@ fn handle_typevar_definition(
 ) -> Result<Type, String> {
     let ExprKind::Call { func, args, .. } = &var.node else {
         return Err(format!(
-            "expression {:?} cannot be handled as a TypeVar or ConstGeneric in global scope",
+            "expression {:?} cannot be handled as a generic parameter in global scope",
             var
         ))
     };