Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/layout.rs')
| -rw-r--r-- | crates/hir-ty/src/layout.rs | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/crates/hir-ty/src/layout.rs b/crates/hir-ty/src/layout.rs new file mode 100644 index 0000000000..7a1cca3143 --- /dev/null +++ b/crates/hir-ty/src/layout.rs @@ -0,0 +1,279 @@ +//! Compute the binary representation of a type + +use std::sync::Arc; + +use base_db::CrateId; +use chalk_ir::{AdtId, TyKind}; +use hir_def::{ + layout::{ + Abi, FieldsShape, Integer, Layout, LayoutCalculator, LayoutError, Primitive, ReprOptions, + RustcEnumVariantIdx, Scalar, Size, StructKind, TargetDataLayout, Variants, WrappingRange, + }, + LocalFieldId, +}; +use stdx::never; + +use crate::{db::HirDatabase, Interner, Substitution, Ty}; + +use self::adt::struct_variant_idx; +pub use self::{ + adt::{layout_of_adt_query, layout_of_adt_recover}, + target::target_data_layout_query, +}; + +macro_rules! user_error { + ($x: expr) => { + return Err(LayoutError::UserError(format!($x))) + }; +} + +mod adt; +mod target; + +struct LayoutCx<'a> { + db: &'a dyn HirDatabase, + krate: CrateId, +} + +impl LayoutCalculator for LayoutCx<'_> { + type TargetDataLayoutRef = Arc<TargetDataLayout>; + + fn delay_bug(&self, txt: &str) { + never!("{}", txt); + } + + fn current_data_layout(&self) -> Arc<TargetDataLayout> { + self.db.target_data_layout(self.krate) + } +} + +fn scalar_unit(dl: &TargetDataLayout, value: Primitive) -> Scalar { + Scalar::Initialized { value, valid_range: WrappingRange::full(value.size(dl)) } +} + +fn scalar(dl: &TargetDataLayout, value: Primitive) -> Layout { + Layout::scalar(dl, scalar_unit(dl, value)) +} + +pub fn layout_of_ty(db: &dyn HirDatabase, ty: &Ty, krate: CrateId) -> Result<Layout, LayoutError> { + let cx = LayoutCx { db, krate }; + let dl = &*cx.current_data_layout(); + Ok(match ty.kind(Interner) { + TyKind::Adt(AdtId(def), subst) => db.layout_of_adt(*def, subst.clone())?, + TyKind::Scalar(s) => match s { + chalk_ir::Scalar::Bool => Layout::scalar( + dl, + Scalar::Initialized { + value: Primitive::Int(Integer::I8, false), + valid_range: WrappingRange { start: 0, end: 1 }, + }, + ), + chalk_ir::Scalar::Char => Layout::scalar( + dl, + Scalar::Initialized { + value: Primitive::Int(Integer::I32, false), + valid_range: WrappingRange { start: 0, end: 0x10FFFF }, + }, + ), + chalk_ir::Scalar::Int(i) => scalar( + dl, + Primitive::Int( + match i { + chalk_ir::IntTy::Isize => dl.ptr_sized_integer(), + chalk_ir::IntTy::I8 => Integer::I8, + chalk_ir::IntTy::I16 => Integer::I16, + chalk_ir::IntTy::I32 => Integer::I32, + chalk_ir::IntTy::I64 => Integer::I64, + chalk_ir::IntTy::I128 => Integer::I128, + }, + true, + ), + ), + chalk_ir::Scalar::Uint(i) => scalar( + dl, + Primitive::Int( + match i { + chalk_ir::UintTy::Usize => dl.ptr_sized_integer(), + chalk_ir::UintTy::U8 => Integer::I8, + chalk_ir::UintTy::U16 => Integer::I16, + chalk_ir::UintTy::U32 => Integer::I32, + chalk_ir::UintTy::U64 => Integer::I64, + chalk_ir::UintTy::U128 => Integer::I128, + }, + false, + ), + ), + chalk_ir::Scalar::Float(f) => scalar( + dl, + match f { + chalk_ir::FloatTy::F32 => Primitive::F32, + chalk_ir::FloatTy::F64 => Primitive::F64, + }, + ), + }, + TyKind::Tuple(len, tys) => { + let kind = if *len == 0 { StructKind::AlwaysSized } else { StructKind::MaybeUnsized }; + + let fields = tys + .iter(Interner) + .map(|k| layout_of_ty(db, k.assert_ty_ref(Interner), krate)) + .collect::<Result<Vec<_>, _>>()?; + let fields = fields.iter().collect::<Vec<_>>(); + let fields = fields.iter().collect::<Vec<_>>(); + cx.univariant(dl, &fields, &ReprOptions::default(), kind).ok_or(LayoutError::Unknown)? + } + TyKind::Array(element, count) => { + let count = match count.data(Interner).value { + chalk_ir::ConstValue::Concrete(c) => match c.interned { + hir_def::type_ref::ConstScalar::Int(x) => x as u64, + hir_def::type_ref::ConstScalar::UInt(x) => x as u64, + hir_def::type_ref::ConstScalar::Unknown => { + user_error!("unknown const generic parameter") + } + _ => user_error!("mismatched type of const generic parameter"), + }, + _ => return Err(LayoutError::HasPlaceholder), + }; + let element = layout_of_ty(db, element, krate)?; + let size = element.size.checked_mul(count, dl).ok_or(LayoutError::SizeOverflow)?; + + let abi = if count != 0 && matches!(element.abi, Abi::Uninhabited) { + Abi::Uninhabited + } else { + Abi::Aggregate { sized: true } + }; + + let largest_niche = if count != 0 { element.largest_niche } else { None }; + + Layout { + variants: Variants::Single { index: struct_variant_idx() }, + fields: FieldsShape::Array { stride: element.size, count }, + abi, + largest_niche, + align: element.align, + size, + } + } + TyKind::Slice(element) => { + let element = layout_of_ty(db, element, krate)?; + Layout { + variants: Variants::Single { index: struct_variant_idx() }, + fields: FieldsShape::Array { stride: element.size, count: 0 }, + abi: Abi::Aggregate { sized: false }, + largest_niche: None, + align: element.align, + size: Size::ZERO, + } + } + // Potentially-wide pointers. + TyKind::Ref(_, _, pointee) | TyKind::Raw(_, pointee) => { + let mut data_ptr = scalar_unit(dl, Primitive::Pointer); + if matches!(ty.kind(Interner), TyKind::Ref(..)) { + data_ptr.valid_range_mut().start = 1; + } + + // let pointee = tcx.normalize_erasing_regions(param_env, pointee); + // if pointee.is_sized(tcx.at(DUMMY_SP), param_env) { + // return Ok(tcx.intern_layout(LayoutS::scalar(cx, data_ptr))); + // } + + let unsized_part = struct_tail_erasing_lifetimes(db, pointee.clone()); + let metadata = match unsized_part.kind(Interner) { + TyKind::Slice(_) | TyKind::Str => { + scalar_unit(dl, Primitive::Int(dl.ptr_sized_integer(), false)) + } + TyKind::Dyn(..) => { + let mut vtable = scalar_unit(dl, Primitive::Pointer); + vtable.valid_range_mut().start = 1; + vtable + } + _ => { + // pointee is sized + return Ok(Layout::scalar(dl, data_ptr)); + } + }; + + // Effectively a (ptr, meta) tuple. + cx.scalar_pair(data_ptr, metadata) + } + TyKind::FnDef(_, _) => layout_of_unit(&cx, dl)?, + TyKind::Str => Layout { + variants: Variants::Single { index: struct_variant_idx() }, + fields: FieldsShape::Array { stride: Size::from_bytes(1), count: 0 }, + abi: Abi::Aggregate { sized: false }, + largest_niche: None, + align: dl.i8_align, + size: Size::ZERO, + }, + TyKind::Never => Layout { + variants: Variants::Single { index: struct_variant_idx() }, + fields: FieldsShape::Primitive, + abi: Abi::Uninhabited, + largest_niche: None, + align: dl.i8_align, + size: Size::ZERO, + }, + TyKind::Dyn(_) | TyKind::Foreign(_) => { + let mut unit = layout_of_unit(&cx, dl)?; + match unit.abi { + Abi::Aggregate { ref mut sized } => *sized = false, + _ => user_error!("bug"), + } + unit + } + TyKind::Function(_) => { + let mut ptr = scalar_unit(dl, Primitive::Pointer); + ptr.valid_range_mut().start = 1; + Layout::scalar(dl, ptr) + } + TyKind::Closure(_, _) + | TyKind::OpaqueType(_, _) + | TyKind::Generator(_, _) + | TyKind::GeneratorWitness(_, _) => return Err(LayoutError::NotImplemented), + TyKind::AssociatedType(_, _) + | TyKind::Error + | TyKind::Alias(_) + | TyKind::Placeholder(_) + | TyKind::BoundVar(_) + | TyKind::InferenceVar(_, _) => return Err(LayoutError::HasPlaceholder), + }) +} + +fn layout_of_unit(cx: &LayoutCx<'_>, dl: &TargetDataLayout) -> Result<Layout, LayoutError> { + cx.univariant::<RustcEnumVariantIdx, &&Layout>( + dl, + &[], + &ReprOptions::default(), + StructKind::AlwaysSized, + ) + .ok_or(LayoutError::Unknown) +} + +fn struct_tail_erasing_lifetimes(db: &dyn HirDatabase, pointee: Ty) -> Ty { + match pointee.kind(Interner) { + TyKind::Adt(AdtId(adt), subst) => match adt { + &hir_def::AdtId::StructId(i) => { + let data = db.struct_data(i); + let mut it = data.variant_data.fields().iter().rev(); + match it.next() { + Some((f, _)) => field_ty(db, i.into(), f, subst), + None => pointee, + } + } + _ => pointee, + }, + _ => pointee, + } +} + +fn field_ty( + db: &dyn HirDatabase, + def: hir_def::VariantId, + fd: LocalFieldId, + subst: &Substitution, +) -> Ty { + db.field_types(def)[fd].clone().substitute(Interner, subst) +} + +#[cfg(test)] +mod tests; |