nac3core/src/codegen/expr.rs

@@ -4,7 +4,7 @@ use crate::{
     codegen::{
         concrete_type::{ConcreteFuncArg, ConcreteTypeEnum, ConcreteTypeStore},
         get_llvm_type,
-        irrt::integer_power,
+        irrt::*,
         CodeGenContext, CodeGenTask,
     },
     symbol_resolver::{SymbolValue, ValueEnum},
@@ -1028,31 +1028,59 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
             }
         }
         ExprKind::Subscript { value, slice, .. } => {
-            if let TypeEnum::TList { .. } = &*ctx.unifier.get_ty(value.custom.unwrap()) {
-                if let ExprKind::Slice { .. } = slice.node {
-                    unimplemented!()
-                } else {
-                    // TODO: bound check
             let v = generator
                 .gen_expr(ctx, value)
                 .unwrap()
                 .to_basic_value_enum(ctx, generator)
                 .into_pointer_value();
+            if let TypeEnum::TList { ty } = &*ctx.unifier.get_ty(value.custom.unwrap()) {
+                let ty = ctx.get_llvm_type(generator, *ty);
+                let arr_ptr = ctx.build_gep_and_load(v, &[zero, zero]).into_pointer_value();
+                if let ExprKind::Slice { lower, upper, step } = &slice.node {
+                    let one = int32.const_int(1, false);
+                    let (start, end, step) =
+                        handle_slice_indices(lower, upper, step, ctx, generator, v);
+                    let length = calculate_len_for_slice_range(
+                        ctx,
+                        start,
+                        ctx.builder
+                            .build_select(
+                                ctx.builder.build_int_compare(
+                                    inkwell::IntPredicate::SLT,
+                                    step,
+                                    zero,
+                                    "is_neg",
+                                ),
+                                ctx.builder.build_int_sub(end, one, "e_min_one"),
+                                ctx.builder.build_int_add(end, one, "e_add_one"),
+                                "final_e",
+                            )
+                            .into_int_value(),
+                        step,
+                    );
+                    let res_array_ret = allocate_list(generator, ctx, ty, length);
+                    let res_ind =
+                        handle_slice_indices(&None, &None, &None, ctx, generator, res_array_ret);
+                    list_slice_assignment(
+                        ctx,
+                        generator.get_size_type(ctx.ctx),
+                        ty,
+                        res_array_ret,
+                        res_ind,
+                        v,
+                        (start, end, step),
+                    );
+                    res_array_ret.into()
+                } else {
+                    // TODO: bound check
                     let index = generator
                         .gen_expr(ctx, slice)
                         .unwrap()
                         .to_basic_value_enum(ctx, generator)
                         .into_int_value();
-                    let zero = int32.const_zero();
-                    let arr_ptr = ctx.build_gep_and_load(v, &[zero, zero]);
-                    ctx.build_gep_and_load(arr_ptr.into_pointer_value(), &[index])
+                    ctx.build_gep_and_load(arr_ptr, &[index])
                 }
             } else {
-                let v = generator
-                    .gen_expr(ctx, value)
-                    .unwrap()
-                    .to_basic_value_enum(ctx, generator)
-                    .into_pointer_value();
                 let index = generator
                     .gen_expr(ctx, slice)
                     .unwrap()

nac3core/src/codegen/irrt/irrt.c

@@ -5,9 +5,12 @@ typedef unsigned _ExtInt(32) uint32_t;
 typedef _ExtInt(64) int64_t;
 typedef unsigned _ExtInt(64) uint64_t;
 
+# define MAX(a, b) (a > b ? a : b)
+# define MIN(a, b) (a > b ? b : a)
+
 // adapted from GNU Scientific Library: https://git.savannah.gnu.org/cgit/gsl.git/tree/sys/pow_int.c
 // need to make sure `exp >= 0` before calling this function
-#define  DEF_INT_EXP(T) T __nac3_irrt_int_exp_##T( \
+#define DEF_INT_EXP(T) T __nac3_int_exp_##T( \
     T base, \
     T exp \
 ) { \
@@ -23,3 +26,106 @@ typedef unsigned _ExtInt(64) uint64_t;
 
 DEF_INT_EXP(int32_t)
 DEF_INT_EXP(int64_t)
+
+
+int32_t __nac3_slice_index_bound(int32_t i, const int32_t len) {
+    if (i < 0) {
+        i = len + i;
+    }
+    if (i < 0) {
+        return 0;
+    } else if (i > len) {
+        return len;
+    }
+    return i;
+}
+
+int32_t __nac3_range_slice_len(const int32_t start, const int32_t end, const int32_t step) {
+    int32_t diff = end - start;
+    if (diff > 0 && step > 0) {
+        return ((diff - 1) / step) + 1;
+    } else if (diff < 0 && step < 0) {
+        return ((diff + 1) / step) + 1;
+    } else {
+        return 0;
+    }
+}
+
+// Handle list assignment and dropping part of the list when
+// both dest_step and src_step are +1.
+// - All the index must *not* be out-of-bound or negative,
+// - The end index is *inclusive*,
+// - The length of src and dest slice size should already
+// be checked: if dest.step == 1 then len(src) <= len(dest) else len(src) == len(dest)
+# define DEF_SLICE_ASSIGN(T) int32_t __nac3_list_slice_assign_##T( \
+    int32_t dest_start, \
+    int32_t dest_end, \
+    int32_t dest_step, \
+    T *dest_arr, \
+    int32_t dest_arr_len, \
+    int32_t src_start, \
+    int32_t src_end, \
+    int32_t src_step, \
+    T *src_arr, \
+    int32_t src_arr_len \
+) { \
+    /* if dest_arr_len == 0, do nothing since we do not support extending list */ \
+    if (dest_arr_len == 0) return dest_arr_len; \
+    /* if both step is 1, memmove directly, handle the dropping of the list, and shrink size */ \
+    if (src_step == dest_step && dest_step == 1) { \
+        const int32_t src_len = (src_end >= src_start) ? (src_end - src_start + 1) : 0; \
+        const int32_t dest_len = (dest_end >= dest_start) ? (dest_end - dest_start + 1) : 0; \
+        if (src_len > 0) { \
+            __builtin_memmove( \
+                dest_arr + dest_start, \
+                src_arr + src_start, \
+                src_len * sizeof(T) \
+            ); \
+        } \
+        if (dest_len > 0) { \
+            /* dropping */ \
+            __builtin_memmove( \
+                dest_arr + dest_start + src_len, \
+                dest_arr + dest_end + 1, \
+                (dest_arr_len - dest_end - 1) * sizeof(T) \
+            ); \
+        } \
+        /* shrink size */ \
+        return dest_arr_len - (dest_len - src_len); \
+    } \
+    /* if two range overlaps, need alloca */ \
+    uint8_t need_alloca = \
+        (dest_arr == src_arr) \
+        && !( \
+            MAX(dest_start, dest_end) < MIN(src_start, src_end) \
+            || MAX(src_start, src_end) < MIN(dest_start, dest_end) \
+        ); \
+    if (need_alloca) { \
+        T *tmp = alloca(src_arr_len * sizeof(T)); \
+        __builtin_memcpy(tmp, src_arr, src_arr_len * sizeof(T)); \
+        src_arr = tmp; \
+    } \
+    int32_t src_ind = src_start; \
+    int32_t dest_ind = dest_start; \
+    for (; \
+        (src_step > 0) ? (src_ind <= src_end) : (src_ind >= src_end); \
+        src_ind += src_step, dest_ind += dest_step \
+    ) { \
+        dest_arr[dest_ind] = src_arr[src_ind]; \
+    } \
+    /* only dest_step == 1 can we shrink the dest list. */ \
+    /* size should be ensured prior to calling this function */ \
+    if (dest_step == 1 && dest_end >= dest_start) { \
+        __builtin_memmove( \
+            dest_arr + dest_ind, \
+            dest_arr + dest_end + 1, \
+            (dest_arr_len - dest_end - 1) * sizeof(T) \
+        ); \
+        return dest_arr_len - (dest_end - dest_ind) - 1; \
+    } \
+    return dest_arr_len; \
+} \
+
+DEF_SLICE_ASSIGN(uint8_t)
+DEF_SLICE_ASSIGN(uint32_t)
+DEF_SLICE_ASSIGN(uint64_t)

nac3core/src/codegen/irrt/mod.rs

@@ -1,11 +1,16 @@
-use super::CodeGenContext;
+use crate::typecheck::typedef::Type;
+
+use super::{CodeGenContext, CodeGenerator};
 use inkwell::{
     attributes::{Attribute, AttributeLoc},
     context::Context,
     memory_buffer::MemoryBuffer,
     module::Module,
-    values::IntValue,
+    types::{BasicTypeEnum, IntType},
+    values::{IntValue, PointerValue},
+    AddressSpace, IntPredicate,
 };
+use nac3parser::ast::Expr;
 
 pub fn load_irrt(ctx: &Context) -> Module {
     let bitcode_buf = MemoryBuffer::create_from_memory_range(
@@ -14,7 +19,12 @@ pub fn load_irrt(ctx: &Context) -> Module {
     );
     let irrt_mod = Module::parse_bitcode_from_buffer(&bitcode_buf, ctx).unwrap();
     let inline_attr = Attribute::get_named_enum_kind_id("alwaysinline");
-    for symbol in &["__nac3_irrt_int_exp_int32_t", "__nac3_irrt_int_exp_int64_t"] {
+    for symbol in &[
+        "__nac3_int_exp_int32_t",
+        "__nac3_int_exp_int64_t",
+        "__nac3_range_slice_len",
+        "__nac3_slice_index_bound",
+    ] {
         let function = irrt_mod.get_function(symbol).unwrap();
         function.add_attribute(AttributeLoc::Function, ctx.create_enum_attribute(inline_attr, 0));
     }
@@ -29,8 +39,8 @@ pub fn integer_power<'ctx, 'a>(
     exp: IntValue<'ctx>,
 ) -> IntValue<'ctx> {
     let symbol = match (base.get_type().get_bit_width(), exp.get_type().get_bit_width()) {
-        (32, 32) => "__nac3_irrt_int_exp_int32_t",
-        (64, 64) => "__nac3_irrt_int_exp_int64_t",
+        (32, 32) => "__nac3_int_exp_int32_t",
+        (64, 64) => "__nac3_int_exp_int64_t",
         _ => unreachable!(),
     };
     let base_type = base.get_type();
@@ -45,3 +55,287 @@ pub fn integer_power<'ctx, 'a>(
         .unwrap_left()
         .into_int_value()
 }
+
+pub fn calculate_len_for_slice_range<'ctx, 'a>(
+    ctx: &mut CodeGenContext<'ctx, 'a>,
+    start: IntValue<'ctx>,
+    end: IntValue<'ctx>,
+    step: IntValue<'ctx>,
+) -> IntValue<'ctx> {
+    const SYMBOL: &str = "__nac3_range_slice_len";
+    let len_func = ctx.module.get_function(SYMBOL).unwrap_or_else(|| {
+        let i32_t = ctx.ctx.i32_type();
+        let fn_t = i32_t.fn_type(&[i32_t.into(), i32_t.into(), i32_t.into()], false);
+        ctx.module.add_function(SYMBOL, fn_t, None)
+    });
+
+    // TODO: assert step != 0, throw exception if not
+    ctx.builder
+        .build_call(len_func, &[start.into(), end.into(), step.into()], "calc_len")
+        .try_as_basic_value()
+        .left()
+        .unwrap()
+        .into_int_value()
+}
+
+/// NOTE: the output value of the end index of this function should be compared ***inclusively***,
+/// because python allows `a[2::-1]`, whose semantic is `[a[2], a[1], a[0]]`, which is equivalent to
+/// NO numeric slice in python.
+///
+/// equivalent code:
+/// ```pseudo_code
+/// match (start, end, step):
+///     case (s, e, None | Some(step)) if step > 0:
+///         return (
+///             match s:
+///                 case None:
+///                     0
+///                 case Some(s):
+///                     handle_in_bound(s)
+///             ,match e:
+///                 case None:
+///                     length - 1
+///                 case Some(e):
+///                     handle_in_bound(e) - 1
+///             ,step == None ? 1 : step
+///         )
+///     case (s, e, Some(step)) if step < 0:
+///         return (
+///             match s:
+///                 case None:
+///                     length - 1
+///                 case Some(s):
+///                     s = handle_in_bound(s)
+///                     if s == length:
+///                         s - 1
+///                     else:
+///                         s
+///             ,match e:
+///                 case None:
+///                     0
+///                 case Some(e):
+///                     handle_in_bound(e) + 1
+///             ,step
+///         )       
+/// ```
+pub fn handle_slice_indices<'a, 'ctx, G: CodeGenerator>(
+    start: &Option<Box<Expr<Option<Type>>>>,
+    end: &Option<Box<Expr<Option<Type>>>>,
+    step: &Option<Box<Expr<Option<Type>>>>,
+    ctx: &mut CodeGenContext<'ctx, 'a>,
+    generator: &mut G,
+    list: PointerValue<'ctx>,
+) -> (IntValue<'ctx>, IntValue<'ctx>, IntValue<'ctx>) {
+    // TODO: throw exception when step is 0
+    let int32 = ctx.ctx.i32_type();
+    let zero = int32.const_zero();
+    let one = int32.const_int(1, false);
+    let length = ctx.build_gep_and_load(list, &[zero, one]).into_int_value();
+    let length = ctx.builder.build_int_truncate_or_bit_cast(length, int32, "leni32");
+    match (start, end, step) {
+        (s, e, None) => (
+            s.as_ref().map_or_else(
+                || int32.const_zero(),
+                |s| handle_slice_index_bound(s, ctx, generator, length),
+            ),
+            {
+                let e = e.as_ref().map_or_else(
+                    || length,
+                    |e| handle_slice_index_bound(e, ctx, generator, length),
+                );
+                ctx.builder.build_int_sub(e, one, "final_end")
+            },
+            one,
+        ),
+        (s, e, Some(step)) => {
+            let step = generator
+                .gen_expr(ctx, step)
+                .unwrap()
+                .to_basic_value_enum(ctx, generator)
+                .into_int_value();
+            let len_id = ctx.builder.build_int_sub(length, one, "lenmin1");
+            let neg = ctx.builder.build_int_compare(IntPredicate::SLT, step, zero, "step_is_neg");
+            (
+                match s {
+                    Some(s) => {
+                        let s = handle_slice_index_bound(s, ctx, generator, length);
+                        ctx.builder
+                            .build_select(
+                                ctx.builder.build_and(
+                                    ctx.builder.build_int_compare(
+                                        IntPredicate::EQ,
+                                        s,
+                                        length,
+                                        "s_eq_len",
+                                    ),
+                                    neg,
+                                    "should_minus_one",
+                                ),
+                                ctx.builder.build_int_sub(s, one, "s_min"),
+                                s,
+                                "final_start",
+                            )
+                            .into_int_value()
+                    }
+                    None => ctx.builder.build_select(neg, len_id, zero, "stt").into_int_value(),
+                },
+                match e {
+                    Some(e) => {
+                        let e = handle_slice_index_bound(e, ctx, generator, length);
+                        ctx.builder
+                            .build_select(
+                                neg,
+                                ctx.builder.build_int_add(e, one, "end_add_one"),
+                                ctx.builder.build_int_sub(e, one, "end_sub_one"),
+                                "final_end",
+                            )
+                            .into_int_value()
+                    }
+                    None => ctx.builder.build_select(neg, zero, len_id, "end").into_int_value(),
+                },
+                step,
+            )
+        }
+    }
+}
+
+/// this function allows index out of range, since python
+/// allows index out of range in slice (`a = [1,2,3]; a[1:10] == [2,3]`).
+pub fn handle_slice_index_bound<'a, 'ctx, G: CodeGenerator>(
+    i: &Expr<Option<Type>>,
+    ctx: &mut CodeGenContext<'ctx, 'a>,
+    generator: &mut G,
+    length: IntValue<'ctx>,
+) -> IntValue<'ctx> {
+    const SYMBOL: &str = "__nac3_slice_index_bound";
+    let func = ctx.module.get_function(SYMBOL).unwrap_or_else(|| {
+        let i32_t = ctx.ctx.i32_type();
+        let fn_t = i32_t.fn_type(&[i32_t.into(), i32_t.into()], false);
+        ctx.module.add_function(SYMBOL, fn_t, None)
+    });
+
+    let i = generator.gen_expr(ctx, i).unwrap().to_basic_value_enum(ctx, generator);
+    ctx.builder
+        .build_call(func, &[i.into(), length.into()], "bounded_ind")
+        .try_as_basic_value()
+        .left()
+        .unwrap()
+        .into_int_value()
+}
+
+/// This function handles 'end' **inclusively**.
+/// Order of tuples assign_idx and value_idx is ('start', 'end', 'step').
+/// Negative index should be handled before entering this function
+pub fn list_slice_assignment<'ctx, 'a>(
+    ctx: &mut CodeGenContext<'ctx, 'a>,
+    size_ty: IntType<'ctx>,
+    ty: BasicTypeEnum<'ctx>,
+    dest_arr: PointerValue<'ctx>,
+    dest_idx: (IntValue<'ctx>, IntValue<'ctx>, IntValue<'ctx>),
+    src_arr: PointerValue<'ctx>,
+    src_idx: (IntValue<'ctx>, IntValue<'ctx>, IntValue<'ctx>),
+) {
+    let int8_ptr = ctx.ctx.i8_type().ptr_type(AddressSpace::Generic);
+    let int32 = ctx.ctx.i32_type();
+    let int32_ptr = int32.ptr_type(AddressSpace::Generic);
+    let int64_ptr = ctx.ctx.i64_type().ptr_type(AddressSpace::Generic);
+    let fun_symbol = if let BasicTypeEnum::IntType(ty) = ty {
+        match ty.get_bit_width() {
+            w if w < 32 => "__nac3_list_slice_assign_uint8_t",
+            32 => "__nac3_list_slice_assign_uint32_t",
+            64 => "__nac3_list_slice_assign_uint64_t",
+            _ => unreachable!(),
+        }
+    } else if ty.is_float_type() {
+        "__nac3_list_slice_assign_uint64_t"
+    } else if ty.is_pointer_type() {
+        match size_ty.get_bit_width() {
+            32 => "__nac3_list_slice_assign_uint32_t",
+            64 => "__nac3_list_slice_assign_uint64_t",
+            _ => unreachable!(),
+        }
+    } else {
+        unreachable!()
+    };
+    let elem_ptr_type = match fun_symbol {
+        "__nac3_list_slice_assign_uint8_t" => int8_ptr,
+        "__nac3_list_slice_assign_uint32_t" => int32_ptr,
+        "__nac3_list_slice_assign_uint64_t" => int64_ptr,
+        _ => unreachable!(),
+    };
+    let slice_assign_fun = ctx.module.get_function(fun_symbol).unwrap_or_else(|| {
+        let fn_t = int32.fn_type(
+            &[
+                int32.into(),         // dest start idx
+                int32.into(),         // dest end idx
+                int32.into(),         // dest step
+                elem_ptr_type.into(), // dest arr ptr
+                int32.into(),         // dest arr len
+                int32.into(),         // src start idx
+                int32.into(),         // src end idx
+                int32.into(),         // src step
+                elem_ptr_type.into(), // src arr ptr
+                int32.into(),         // src arr len
+            ],
+            false,
+        );
+        ctx.module.add_function(fun_symbol, fn_t, None)
+    });
+
+    let zero = int32.const_zero();
+    let one = int32.const_int(1, false);
+    let dest_arr_ptr = ctx.build_gep_and_load(dest_arr, &[zero, zero]);
+    let dest_arr_ptr = ctx.builder.build_pointer_cast(
+        dest_arr_ptr.into_pointer_value(),
+        elem_ptr_type,
+        "dest_arr_ptr_cast",
+    );
+    let dest_len = ctx.build_gep_and_load(dest_arr, &[zero, one]).into_int_value();
+    let dest_len = ctx.builder.build_int_truncate_or_bit_cast(dest_len, int32, "srclen32");
+    let src_arr_ptr = ctx.build_gep_and_load(src_arr, &[zero, zero]);
+    let src_arr_ptr = ctx.builder.build_pointer_cast(
+        src_arr_ptr.into_pointer_value(),
+        elem_ptr_type,
+        "src_arr_ptr_cast",
+    );
+    let src_len = ctx.build_gep_and_load(src_arr, &[zero, one]).into_int_value();
+    let src_len = ctx.builder.build_int_truncate_or_bit_cast(src_len, int32, "srclen32");
+
+    // index in bound and positive should be done
+    // TODO: assert if dest.step == 1 then len(src) <= len(dest) else len(src) == len(dest), and
+    // throw exception if not satisfied
+    let new_len = ctx
+        .builder
+        .build_call(
+            slice_assign_fun,
+            &[
+                dest_idx.0.into(),   // dest start idx
+                dest_idx.1.into(),   // dest end idx
+                dest_idx.2.into(),   // dest step
+                dest_arr_ptr.into(), // dest arr ptr
+                dest_len.into(),     // dest arr len
+                src_idx.0.into(),    // src start idx
+                src_idx.1.into(),    // src end idx
+                src_idx.2.into(),    // src step
+                src_arr_ptr.into(),  // src arr ptr
+                src_len.into(),      // src arr len
+            ],
+            "slice_assign",
+        )
+        .try_as_basic_value()
+        .unwrap_left()
+        .into_int_value();
+    // update length
+    let need_update =
+        ctx.builder.build_int_compare(IntPredicate::NE, new_len, dest_len, "need_update");
+    let current = ctx.builder.get_insert_block().unwrap().get_parent().unwrap();
+    let update_bb = ctx.ctx.append_basic_block(current, "update");
+    let cont_bb = ctx.ctx.append_basic_block(current, "cont");
+    ctx.builder.build_conditional_branch(need_update, update_bb, cont_bb);
+    ctx.builder.position_at_end(update_bb);
+    let dest_len_ptr = unsafe { ctx.builder.build_gep(dest_arr, &[zero, one], "dest_len_ptr") };
+    let new_len = ctx.builder.build_int_z_extend_or_bit_cast(new_len, size_ty, "new_len");
+    ctx.builder.build_store(dest_len_ptr, new_len);
+    ctx.builder.build_unconditional_branch(cont_bb);
+    ctx.builder.position_at_end(cont_bb);
+}

nac3core/src/codegen/stmt.rs

@@ -1,7 +1,13 @@
 use super::{
-    super::symbol_resolver::ValueEnum, expr::destructure_range, CodeGenContext, CodeGenerator,
+    super::symbol_resolver::ValueEnum,
+    expr::destructure_range,
+    irrt::{handle_slice_indices, list_slice_assignment},
+    CodeGenContext, CodeGenerator,
+};
+use crate::{
+    codegen::expr::gen_binop_expr,
+    typecheck::typedef::{Type, TypeEnum},
 };
-use crate::{codegen::expr::gen_binop_expr, typecheck::typedef::Type};
 use inkwell::{
     types::BasicTypeEnum,
     values::{BasicValue, BasicValueEnum, PointerValue},
@@ -97,6 +103,41 @@ pub fn gen_assign<'ctx, 'a, G: CodeGenerator>(
             unreachable!()
         }
     } else {
+        match &target.node {
+            ExprKind::Subscript { value: ls, slice, .. }
+                if matches!(&slice.node, ExprKind::Slice { .. }) =>
+            {
+                if let ExprKind::Slice { lower, upper, step } = &slice.node {
+                    let ls = generator
+                        .gen_expr(ctx, ls)
+                        .unwrap()
+                        .to_basic_value_enum(ctx, generator)
+                        .into_pointer_value();
+                    let (start, end, step) =
+                        handle_slice_indices(lower, upper, step, ctx, generator, ls);
+                    let value = value.to_basic_value_enum(ctx, generator).into_pointer_value();
+                    let ty = if let TypeEnum::TList { ty } =
+                        &*ctx.unifier.get_ty(target.custom.unwrap())
+                    {
+                        ctx.get_llvm_type(generator, *ty)
+                    } else {
+                        unreachable!()
+                    };
+                    let src_ind = handle_slice_indices(&None, &None, &None, ctx, generator, value);
+                    list_slice_assignment(
+                        ctx,
+                        generator.get_size_type(ctx.ctx),
+                        ty,
+                        ls,
+                        (start, end, step),
+                        value,
+                        src_ind,
+                    )
+                } else {
+                    unreachable!()
+                }
+            }
+            _ => {
                 let ptr = generator.gen_store_target(ctx, target);
                 if let ExprKind::Name { id, .. } = &target.node {
                     let (_, static_value, counter) = ctx.var_assignment.get_mut(id).unwrap();
@@ -108,6 +149,8 @@ pub fn gen_assign<'ctx, 'a, G: CodeGenerator>(
                 let val = value.to_basic_value_enum(ctx, generator);
                 ctx.builder.build_store(ptr, val);
             }
+        }
+    }
 }
 
 pub fn gen_for<'ctx, 'a, G: CodeGenerator>(

nac3core/src/toplevel/builtins.rs

@@ -1,7 +1,10 @@
-use std::cell::RefCell;
-use inkwell::{IntPredicate::{self, *}, FloatPredicate, values::IntValue};
-use crate::{symbol_resolver::SymbolValue, codegen::expr::destructure_range};
 use super::*;
+use crate::{
+    codegen::{expr::destructure_range, irrt::calculate_len_for_slice_range},
+    symbol_resolver::SymbolValue,
+};
+use inkwell::{FloatPredicate, IntPredicate};
+use std::cell::RefCell;
 
 type BuiltinInfo = (
     Vec<(Arc<RwLock<TopLevelDef>>, Option<Stmt>)>,
@@ -622,78 +625,3 @@ pub fn get_builtins(primitives: &mut (PrimitiveStore, Unifier)) -> BuiltinInfo {
         ]
     )
 }
-
-// equivalent code:
-// def length(start, end, step != 0):
-//     diff = end - start
-//     if diff > 0 and step > 0:
-//          return ((diff - 1) // step) + 1
-//     elif diff < 0 and step < 0:
-//          return ((diff + 1) // step) + 1
-//     else:
-//          return 0
-pub fn calculate_len_for_slice_range<'ctx, 'a>(
-    ctx: &mut CodeGenContext<'ctx, 'a>,
-    start: IntValue<'ctx>,
-    end: IntValue<'ctx>,
-    step: IntValue<'ctx>,
-) -> IntValue<'ctx> {
-    let int32 = ctx.ctx.i32_type();
-    let start = ctx.builder.build_int_s_extend(start, int32, "start");
-    let end = ctx.builder.build_int_s_extend(end, int32, "end");
-    let step = ctx.builder.build_int_s_extend(step, int32, "step");
-    let diff = ctx.builder.build_int_sub(end, start, "diff");
-
-    let diff_pos = ctx.builder.build_int_compare(SGT, diff, int32.const_zero(), "diffpos");
-    let step_pos = ctx.builder.build_int_compare(SGT, step, int32.const_zero(), "steppos");
-    let test_1 = ctx.builder.build_and(diff_pos, step_pos, "bothpos");
-
-    let current = ctx.builder.get_insert_block().unwrap().get_parent().unwrap();
-    let then_bb = ctx.ctx.append_basic_block(current, "then");
-    let else_bb = ctx.ctx.append_basic_block(current, "else");
-    let then_bb_2 = ctx.ctx.append_basic_block(current, "then_2");
-    let else_bb_2 = ctx.ctx.append_basic_block(current, "else_2");
-    let cont_bb_2 = ctx.ctx.append_basic_block(current, "cont_2");
-    let cont_bb = ctx.ctx.append_basic_block(current, "cont");
-    ctx.builder.build_conditional_branch(test_1, then_bb, else_bb);
-
-    ctx.builder.position_at_end(then_bb);
-    let length_pos = {
-        let diff_pos_min_1 = ctx.builder.build_int_sub(diff, int32.const_int(1, false), "diffminone");
-        let length_pos = ctx.builder.build_int_signed_div(diff_pos_min_1, step, "div");
-        ctx.builder.build_int_add(length_pos, int32.const_int(1, false), "add1")
-    };
-    ctx.builder.build_unconditional_branch(cont_bb);
-
-    ctx.builder.position_at_end(else_bb);
-    let phi_1 = {
-        let diff_neg = ctx.builder.build_int_compare(SLT, diff, int32.const_zero(), "diffneg");
-        let step_neg = ctx.builder.build_int_compare(SLT, step, int32.const_zero(), "stepneg");
-        let test_2 = ctx.builder.build_and(diff_neg, step_neg, "bothneg");
-
-        ctx.builder.build_conditional_branch(test_2, then_bb_2, else_bb_2);
-
-        ctx.builder.position_at_end(then_bb_2);
-        let length_neg = {
-            let diff_neg_add_1 = ctx.builder.build_int_add(diff, int32.const_int(1, false), "diffminone");
-            let length_neg = ctx.builder.build_int_signed_div(diff_neg_add_1, step, "div");
-            ctx.builder.build_int_add(length_neg, int32.const_int(1, false), "add1")
-        };
-        ctx.builder.build_unconditional_branch(cont_bb_2);
-
-        ctx.builder.position_at_end(else_bb_2);
-        let length_zero = int32.const_zero();
-        ctx.builder.build_unconditional_branch(cont_bb_2);
-
-        ctx.builder.position_at_end(cont_bb_2);
-        let phi_1 = ctx.builder.build_phi(int32, "lenphi1");
-        phi_1.add_incoming(&[(&length_neg, then_bb_2), (&length_zero, else_bb_2)]);
-        phi_1.as_basic_value().into_int_value()
-    };
-    ctx.builder.build_unconditional_branch(cont_bb);
-
-    ctx.builder.position_at_end(cont_bb);
-    let phi = ctx.builder.build_phi(int32, "lenphi");
-    phi.add_incoming(&[(&length_pos, then_bb), (&phi_1, cont_bb_2)]);
-    phi.as_basic_value().into_int_value()
-}