diff options
Diffstat (limited to 'compiler/rustc_middle/src/ty/layout.rs')
| -rw-r--r-- | compiler/rustc_middle/src/ty/layout.rs | 109 |
1 files changed, 91 insertions, 18 deletions
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs index fa0711193df..8bdc7efa0bb 100644 --- a/compiler/rustc_middle/src/ty/layout.rs +++ b/compiler/rustc_middle/src/ty/layout.rs @@ -631,30 +631,106 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> { } // SIMD vector types. - ty::Adt(def, ..) if def.repr.simd() => { - let element = self.layout_of(ty.simd_type(tcx))?; - let count = ty.simd_size(tcx); - assert!(count > 0); - let scalar = match element.abi { - Abi::Scalar(ref scalar) => scalar.clone(), - _ => { + ty::Adt(def, substs) if def.repr.simd() => { + // Supported SIMD vectors are homogeneous ADTs with at least one field: + // + // * #[repr(simd)] struct S(T, T, T, T); + // * #[repr(simd)] struct S { x: T, y: T, z: T, w: T } + // * #[repr(simd)] struct S([T; 4]) + // + // where T is a primitive scalar (integer/float/pointer). + + // SIMD vectors with zero fields are not supported. + // (should be caught by typeck) + if def.non_enum_variant().fields.is_empty() { + tcx.sess.fatal(&format!("monomorphising SIMD type `{}` of zero length", ty)); + } + + // Type of the first ADT field: + let f0_ty = def.non_enum_variant().fields[0].ty(tcx, substs); + + // Heterogeneous SIMD vectors are not supported: + // (should be caught by typeck) + for fi in &def.non_enum_variant().fields { + if fi.ty(tcx, substs) != f0_ty { + tcx.sess.fatal(&format!("monomorphising heterogeneous SIMD type `{}`", ty)); + } + } + + // The element type and number of elements of the SIMD vector + // are obtained from: + // + // * the element type and length of the single array field, if + // the first field is of array type, or + // + // * the homogenous field type and the number of fields. + let (e_ty, e_len, is_array) = if let ty::Array(e_ty, _) = f0_ty.kind() { + // First ADT field is an array: + + // SIMD vectors with multiple array fields are not supported: + // (should be caught by typeck) + if def.non_enum_variant().fields.len() != 1 { tcx.sess.fatal(&format!( - "monomorphising SIMD type `{}` with \ - a non-machine element type `{}`", - ty, element.ty + "monomorphising SIMD type `{}` with more than one array field", + ty )); } + + // Extract the number of elements from the layout of the array field: + let len = if let Ok(TyAndLayout { + layout: Layout { fields: FieldsShape::Array { count, .. }, .. }, + .. + }) = self.layout_of(f0_ty) + { + count + } else { + return Err(LayoutError::Unknown(ty)); + }; + + (*e_ty, *len, true) + } else { + // First ADT field is not an array: + (f0_ty, def.non_enum_variant().fields.len() as _, false) }; - let size = - element.size.checked_mul(count, dl).ok_or(LayoutError::SizeOverflow(ty))?; + + // SIMD vectors of zero length are not supported. + // + // Can't be caught in typeck if the array length is generic. + if e_len == 0 { + tcx.sess.fatal(&format!("monomorphising SIMD type `{}` of zero length", ty)); + } + + // Compute the ABI of the element type: + let e_ly = self.layout_of(e_ty)?; + let e_abi = if let Abi::Scalar(ref scalar) = e_ly.abi { + scalar.clone() + } else { + // This error isn't caught in typeck, e.g., if + // the element type of the vector is generic. + tcx.sess.fatal(&format!( + "monomorphising SIMD type `{}` with a non-primitive-scalar \ + (integer/float/pointer) element type `{}`", + ty, e_ty + )) + }; + + // Compute the size and alignment of the vector: + let size = e_ly.size.checked_mul(e_len, dl).ok_or(LayoutError::SizeOverflow(ty))?; let align = dl.vector_align(size); let size = size.align_to(align.abi); + // Compute the placement of the vector fields: + let fields = if is_array { + FieldsShape::Arbitrary { offsets: vec![Size::ZERO], memory_index: vec![0] } + } else { + FieldsShape::Array { stride: e_ly.size, count: e_len } + }; + tcx.intern_layout(Layout { variants: Variants::Single { index: VariantIdx::new(0) }, - fields: FieldsShape::Array { stride: element.size, count }, - abi: Abi::Vector { element: scalar, count }, - largest_niche: element.largest_niche.clone(), + fields, + abi: Abi::Vector { element: e_abi, count: e_len }, + largest_niche: e_ly.largest_niche.clone(), size, align, }) @@ -2121,9 +2197,6 @@ where ty::Tuple(tys) => tys[i].expect_ty(), - // SIMD vector types. - ty::Adt(def, ..) if def.repr.simd() => this.ty.simd_type(tcx), - // ADTs. ty::Adt(def, substs) => { match this.variants { |