| use crate::abi::FnAbi; |
| use crate::common::*; |
| use crate::type_::Type; |
| use rustc_codegen_ssa::traits::*; |
| use rustc_middle::bug; |
| use rustc_middle::ty::layout::{FnAbiExt, TyAndLayout}; |
| use rustc_middle::ty::print::with_no_trimmed_paths; |
| use rustc_middle::ty::{self, Ty, TypeFoldable}; |
| use rustc_target::abi::{Abi, AddressSpace, Align, FieldsShape}; |
| use rustc_target::abi::{Int, Pointer, F32, F64}; |
| use rustc_target::abi::{LayoutOf, PointeeInfo, Scalar, Size, TyAndLayoutMethods, Variants}; |
| use tracing::debug; |
| |
| use std::fmt::Write; |
| |
| fn uncached_llvm_type<'a, 'tcx>( |
| cx: &CodegenCx<'a, 'tcx>, |
| layout: TyAndLayout<'tcx>, |
| defer: &mut Option<(&'a Type, TyAndLayout<'tcx>)>, |
| ) -> &'a Type { |
| match layout.abi { |
| Abi::Scalar(_) => bug!("handled elsewhere"), |
| Abi::Vector { ref element, count } => { |
| let element = layout.scalar_llvm_type_at(cx, element, Size::ZERO); |
| return cx.type_vector(element, count); |
| } |
| Abi::ScalarPair(..) => { |
| return cx.type_struct( |
| &[ |
| layout.scalar_pair_element_llvm_type(cx, 0, false), |
| layout.scalar_pair_element_llvm_type(cx, 1, false), |
| ], |
| false, |
| ); |
| } |
| Abi::Uninhabited | Abi::Aggregate { .. } => {} |
| } |
| |
| let name = match layout.ty.kind() { |
| // FIXME(eddyb) producing readable type names for trait objects can result |
| // in problematically distinct types due to HRTB and subtyping (see #47638). |
| // ty::Dynamic(..) | |
| ty::Adt(..) | ty::Closure(..) | ty::Foreign(..) | ty::Generator(..) | ty::Str |
| if !cx.sess().fewer_names() => |
| { |
| let mut name = with_no_trimmed_paths(|| layout.ty.to_string()); |
| if let (&ty::Adt(def, _), &Variants::Single { index }) = |
| (layout.ty.kind(), &layout.variants) |
| { |
| if def.is_enum() && !def.variants.is_empty() { |
| write!(&mut name, "::{}", def.variants[index].ident).unwrap(); |
| } |
| } |
| if let (&ty::Generator(_, _, _), &Variants::Single { index }) = |
| (layout.ty.kind(), &layout.variants) |
| { |
| write!(&mut name, "::{}", ty::GeneratorSubsts::variant_name(index)).unwrap(); |
| } |
| Some(name) |
| } |
| ty::Adt(..) => { |
| // If `Some` is returned then a named struct is created in LLVM. Name collisions are |
| // avoided by LLVM (with increasing suffixes). If rustc doesn't generate names then that |
| // can improve perf. |
| Some(String::new()) |
| } |
| _ => None, |
| }; |
| |
| match layout.fields { |
| FieldsShape::Primitive | FieldsShape::Union(_) => { |
| let fill = cx.type_padding_filler(layout.size, layout.align.abi); |
| let packed = false; |
| match name { |
| None => cx.type_struct(&[fill], packed), |
| Some(ref name) => { |
| let llty = cx.type_named_struct(name); |
| cx.set_struct_body(llty, &[fill], packed); |
| llty |
| } |
| } |
| } |
| FieldsShape::Array { count, .. } => cx.type_array(layout.field(cx, 0).llvm_type(cx), count), |
| FieldsShape::Arbitrary { .. } => match name { |
| None => { |
| let (llfields, packed) = struct_llfields(cx, layout); |
| cx.type_struct(&llfields, packed) |
| } |
| Some(ref name) => { |
| let llty = cx.type_named_struct(name); |
| *defer = Some((llty, layout)); |
| llty |
| } |
| }, |
| } |
| } |
| |
| fn struct_llfields<'a, 'tcx>( |
| cx: &CodegenCx<'a, 'tcx>, |
| layout: TyAndLayout<'tcx>, |
| ) -> (Vec<&'a Type>, bool) { |
| debug!("struct_llfields: {:#?}", layout); |
| let field_count = layout.fields.count(); |
| |
| let mut packed = false; |
| let mut offset = Size::ZERO; |
| let mut prev_effective_align = layout.align.abi; |
| let mut result: Vec<_> = Vec::with_capacity(1 + field_count * 2); |
| for i in layout.fields.index_by_increasing_offset() { |
| let target_offset = layout.fields.offset(i as usize); |
| let field = layout.field(cx, i); |
| let effective_field_align = |
| layout.align.abi.min(field.align.abi).restrict_for_offset(target_offset); |
| packed |= effective_field_align < field.align.abi; |
| |
| debug!( |
| "struct_llfields: {}: {:?} offset: {:?} target_offset: {:?} \ |
| effective_field_align: {}", |
| i, |
| field, |
| offset, |
| target_offset, |
| effective_field_align.bytes() |
| ); |
| assert!(target_offset >= offset); |
| let padding = target_offset - offset; |
| let padding_align = prev_effective_align.min(effective_field_align); |
| assert_eq!(offset.align_to(padding_align) + padding, target_offset); |
| result.push(cx.type_padding_filler(padding, padding_align)); |
| debug!(" padding before: {:?}", padding); |
| |
| result.push(field.llvm_type(cx)); |
| offset = target_offset + field.size; |
| prev_effective_align = effective_field_align; |
| } |
| if !layout.is_unsized() && field_count > 0 { |
| if offset > layout.size { |
| bug!("layout: {:#?} stride: {:?} offset: {:?}", layout, layout.size, offset); |
| } |
| let padding = layout.size - offset; |
| let padding_align = prev_effective_align; |
| assert_eq!(offset.align_to(padding_align) + padding, layout.size); |
| debug!( |
| "struct_llfields: pad_bytes: {:?} offset: {:?} stride: {:?}", |
| padding, offset, layout.size |
| ); |
| result.push(cx.type_padding_filler(padding, padding_align)); |
| assert_eq!(result.len(), 1 + field_count * 2); |
| } else { |
| debug!("struct_llfields: offset: {:?} stride: {:?}", offset, layout.size); |
| } |
| |
| (result, packed) |
| } |
| |
| impl<'a, 'tcx> CodegenCx<'a, 'tcx> { |
| pub fn align_of(&self, ty: Ty<'tcx>) -> Align { |
| self.layout_of(ty).align.abi |
| } |
| |
| pub fn size_of(&self, ty: Ty<'tcx>) -> Size { |
| self.layout_of(ty).size |
| } |
| |
| pub fn size_and_align_of(&self, ty: Ty<'tcx>) -> (Size, Align) { |
| let layout = self.layout_of(ty); |
| (layout.size, layout.align.abi) |
| } |
| } |
| |
| pub trait LayoutLlvmExt<'tcx> { |
| fn is_llvm_immediate(&self) -> bool; |
| fn is_llvm_scalar_pair(&self) -> bool; |
| fn llvm_type<'a>(&self, cx: &CodegenCx<'a, 'tcx>) -> &'a Type; |
| fn immediate_llvm_type<'a>(&self, cx: &CodegenCx<'a, 'tcx>) -> &'a Type; |
| fn scalar_llvm_type_at<'a>( |
| &self, |
| cx: &CodegenCx<'a, 'tcx>, |
| scalar: &Scalar, |
| offset: Size, |
| ) -> &'a Type; |
| fn scalar_pair_element_llvm_type<'a>( |
| &self, |
| cx: &CodegenCx<'a, 'tcx>, |
| index: usize, |
| immediate: bool, |
| ) -> &'a Type; |
| fn llvm_field_index(&self, index: usize) -> u64; |
| fn pointee_info_at<'a>(&self, cx: &CodegenCx<'a, 'tcx>, offset: Size) -> Option<PointeeInfo>; |
| } |
| |
| impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> { |
| fn is_llvm_immediate(&self) -> bool { |
| match self.abi { |
| Abi::Scalar(_) | Abi::Vector { .. } => true, |
| Abi::ScalarPair(..) => false, |
| Abi::Uninhabited | Abi::Aggregate { .. } => self.is_zst(), |
| } |
| } |
| |
| fn is_llvm_scalar_pair(&self) -> bool { |
| match self.abi { |
| Abi::ScalarPair(..) => true, |
| Abi::Uninhabited | Abi::Scalar(_) | Abi::Vector { .. } | Abi::Aggregate { .. } => false, |
| } |
| } |
| |
| /// Gets the LLVM type corresponding to a Rust type, i.e., `rustc_middle::ty::Ty`. |
| /// The pointee type of the pointer in `PlaceRef` is always this type. |
| /// For sized types, it is also the right LLVM type for an `alloca` |
| /// containing a value of that type, and most immediates (except `bool`). |
| /// Unsized types, however, are represented by a "minimal unit", e.g. |
| /// `[T]` becomes `T`, while `str` and `Trait` turn into `i8` - this |
| /// is useful for indexing slices, as `&[T]`'s data pointer is `T*`. |
| /// If the type is an unsized struct, the regular layout is generated, |
| /// with the inner-most trailing unsized field using the "minimal unit" |
| /// of that field's type - this is useful for taking the address of |
| /// that field and ensuring the struct has the right alignment. |
| fn llvm_type<'a>(&self, cx: &CodegenCx<'a, 'tcx>) -> &'a Type { |
| if let Abi::Scalar(ref scalar) = self.abi { |
| // Use a different cache for scalars because pointers to DSTs |
| // can be either fat or thin (data pointers of fat pointers). |
| if let Some(&llty) = cx.scalar_lltypes.borrow().get(&self.ty) { |
| return llty; |
| } |
| let llty = match *self.ty.kind() { |
| ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => { |
| cx.type_ptr_to(cx.layout_of(ty).llvm_type(cx)) |
| } |
| ty::Adt(def, _) if def.is_box() => { |
| cx.type_ptr_to(cx.layout_of(self.ty.boxed_ty()).llvm_type(cx)) |
| } |
| ty::FnPtr(sig) => cx.fn_ptr_backend_type(&FnAbi::of_fn_ptr(cx, sig, &[])), |
| _ => self.scalar_llvm_type_at(cx, scalar, Size::ZERO), |
| }; |
| cx.scalar_lltypes.borrow_mut().insert(self.ty, llty); |
| return llty; |
| } |
| |
| // Check the cache. |
| let variant_index = match self.variants { |
| Variants::Single { index } => Some(index), |
| _ => None, |
| }; |
| if let Some(&llty) = cx.lltypes.borrow().get(&(self.ty, variant_index)) { |
| return llty; |
| } |
| |
| debug!("llvm_type({:#?})", self); |
| |
| assert!(!self.ty.has_escaping_bound_vars(), "{:?} has escaping bound vars", self.ty); |
| |
| // Make sure lifetimes are erased, to avoid generating distinct LLVM |
| // types for Rust types that only differ in the choice of lifetimes. |
| let normal_ty = cx.tcx.erase_regions(&self.ty); |
| |
| let mut defer = None; |
| let llty = if self.ty != normal_ty { |
| let mut layout = cx.layout_of(normal_ty); |
| if let Some(v) = variant_index { |
| layout = layout.for_variant(cx, v); |
| } |
| layout.llvm_type(cx) |
| } else { |
| uncached_llvm_type(cx, *self, &mut defer) |
| }; |
| debug!("--> mapped {:#?} to llty={:?}", self, llty); |
| |
| cx.lltypes.borrow_mut().insert((self.ty, variant_index), llty); |
| |
| if let Some((llty, layout)) = defer { |
| let (llfields, packed) = struct_llfields(cx, layout); |
| cx.set_struct_body(llty, &llfields, packed) |
| } |
| |
| llty |
| } |
| |
| fn immediate_llvm_type<'a>(&self, cx: &CodegenCx<'a, 'tcx>) -> &'a Type { |
| if let Abi::Scalar(ref scalar) = self.abi { |
| if scalar.is_bool() { |
| return cx.type_i1(); |
| } |
| } |
| self.llvm_type(cx) |
| } |
| |
| fn scalar_llvm_type_at<'a>( |
| &self, |
| cx: &CodegenCx<'a, 'tcx>, |
| scalar: &Scalar, |
| offset: Size, |
| ) -> &'a Type { |
| match scalar.value { |
| Int(i, _) => cx.type_from_integer(i), |
| F32 => cx.type_f32(), |
| F64 => cx.type_f64(), |
| Pointer => { |
| // If we know the alignment, pick something better than i8. |
| let (pointee, address_space) = |
| if let Some(pointee) = self.pointee_info_at(cx, offset) { |
| (cx.type_pointee_for_align(pointee.align), pointee.address_space) |
| } else { |
| (cx.type_i8(), AddressSpace::DATA) |
| }; |
| cx.type_ptr_to_ext(pointee, address_space) |
| } |
| } |
| } |
| |
| fn scalar_pair_element_llvm_type<'a>( |
| &self, |
| cx: &CodegenCx<'a, 'tcx>, |
| index: usize, |
| immediate: bool, |
| ) -> &'a Type { |
| // HACK(eddyb) special-case fat pointers until LLVM removes |
| // pointee types, to avoid bitcasting every `OperandRef::deref`. |
| match self.ty.kind() { |
| ty::Ref(..) | ty::RawPtr(_) => { |
| return self.field(cx, index).llvm_type(cx); |
| } |
| ty::Adt(def, _) if def.is_box() => { |
| let ptr_ty = cx.tcx.mk_mut_ptr(self.ty.boxed_ty()); |
| return cx.layout_of(ptr_ty).scalar_pair_element_llvm_type(cx, index, immediate); |
| } |
| _ => {} |
| } |
| |
| let (a, b) = match self.abi { |
| Abi::ScalarPair(ref a, ref b) => (a, b), |
| _ => bug!("TyAndLayout::scalar_pair_element_llty({:?}): not applicable", self), |
| }; |
| let scalar = [a, b][index]; |
| |
| // Make sure to return the same type `immediate_llvm_type` would when |
| // dealing with an immediate pair. This means that `(bool, bool)` is |
| // effectively represented as `{i8, i8}` in memory and two `i1`s as an |
| // immediate, just like `bool` is typically `i8` in memory and only `i1` |
| // when immediate. We need to load/store `bool` as `i8` to avoid |
| // crippling LLVM optimizations or triggering other LLVM bugs with `i1`. |
| if immediate && scalar.is_bool() { |
| return cx.type_i1(); |
| } |
| |
| let offset = |
| if index == 0 { Size::ZERO } else { a.value.size(cx).align_to(b.value.align(cx).abi) }; |
| self.scalar_llvm_type_at(cx, scalar, offset) |
| } |
| |
| fn llvm_field_index(&self, index: usize) -> u64 { |
| match self.abi { |
| Abi::Scalar(_) | Abi::ScalarPair(..) => { |
| bug!("TyAndLayout::llvm_field_index({:?}): not applicable", self) |
| } |
| _ => {} |
| } |
| match self.fields { |
| FieldsShape::Primitive | FieldsShape::Union(_) => { |
| bug!("TyAndLayout::llvm_field_index({:?}): not applicable", self) |
| } |
| |
| FieldsShape::Array { .. } => index as u64, |
| |
| FieldsShape::Arbitrary { .. } => 1 + (self.fields.memory_index(index) as u64) * 2, |
| } |
| } |
| |
| fn pointee_info_at<'a>(&self, cx: &CodegenCx<'a, 'tcx>, offset: Size) -> Option<PointeeInfo> { |
| if let Some(&pointee) = cx.pointee_infos.borrow().get(&(self.ty, offset)) { |
| return pointee; |
| } |
| |
| let result = Ty::pointee_info_at(*self, cx, offset); |
| |
| cx.pointee_infos.borrow_mut().insert((self.ty, offset), result); |
| result |
| } |
| } |