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nac3core: add missing bound check and negative index handling for list subscription assignment

This commit is contained in:
ychenfo 2022-04-09 04:56:31 +08:00
parent 86ce513cb5
commit 26187bff0b
1 changed files with 42 additions and 1 deletions
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43
nac3core/src/codegen/stmt.rs
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@ -72,17 +72,58 @@ pub fn gen_store_target<'ctx, 'a, G: CodeGenerator>(
}
}
ExprKind::Subscript { value, slice, .. } => {
assert!(matches!(
ctx.unifier.get_ty_immutable(value.custom.unwrap()).as_ref(),
TypeEnum::TList { .. },
));
let i32_type = ctx.ctx.i32_type();
let zero = i32_type.const_zero();
let v = generator
.gen_expr(ctx, value)?
.unwrap()
.to_basic_value_enum(ctx, generator)?
.into_pointer_value();
let index = generator
let len = ctx
.build_gep_and_load(v, &[zero, i32_type.const_int(1, false)])
.into_int_value();
let raw_index = generator
.gen_expr(ctx, slice)?
.unwrap()
.to_basic_value_enum(ctx, generator)?
.into_int_value();
let raw_index = ctx.builder.build_int_s_extend(
raw_index,
generator.get_size_type(ctx.ctx),
"sext",
);
// handle negative index
let is_negative = ctx.builder.build_int_compare(
inkwell::IntPredicate::SLT,
raw_index,
generator.get_size_type(ctx.ctx).const_zero(),
"is_neg",
);
let adjusted = ctx.builder.build_int_add(raw_index, len, "adjusted");
let index = ctx
.builder
.build_select(is_negative, adjusted, raw_index, "index")
.into_int_value();
// unsigned less than is enough, because negative index after adjustment is
// bigger than the length (for unsigned cmp)
let bound_check = ctx.builder.build_int_compare(
inkwell::IntPredicate::ULT,
index,
len,
"inbound",
);
ctx.make_assert(
generator,
bound_check,
"0:IndexError",
"index {0} out of bounds 0:{1}",
[Some(raw_index), Some(len), None],
slice.location,
);
unsafe {
let arr_ptr = ctx
.build_gep_and_load(v, &[i32_type.const_zero(), i32_type.const_zero()])