diff options
Diffstat (limited to 'compiler/rustc_transmute/src/layout/tree.rs')
| -rw-r--r-- | compiler/rustc_transmute/src/layout/tree.rs | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/compiler/rustc_transmute/src/layout/tree.rs b/compiler/rustc_transmute/src/layout/tree.rs index c3fd771b797..b5ce465a173 100644 --- a/compiler/rustc_transmute/src/layout/tree.rs +++ b/compiler/rustc_transmute/src/layout/tree.rs @@ -175,7 +175,7 @@ pub(crate) mod rustc { use rustc_middle::ty::{self, AdtDef, AdtKind, List, ScalarInt, Ty, TyCtxt, TypeVisitableExt}; use rustc_span::ErrorGuaranteed; use rustc_target::abi::{ - FieldIdx, FieldsShape, Layout, Size, TyAndLayout, VariantIdx, Variants, + FieldIdx, FieldsShape, Layout, Size, TagEncoding, TyAndLayout, VariantIdx, Variants, }; use super::Tree; @@ -319,11 +319,17 @@ pub(crate) mod rustc { assert!(def.is_enum()); // Computes the variant of a given index. - let layout_of_variant = |index| { + let layout_of_variant = |index, encoding: Option<TagEncoding<VariantIdx>>| { let tag = cx.tcx.tag_for_variant((cx.tcx.erase_regions(ty), index)); let variant_def = Def::Variant(def.variant(index)); let variant_layout = ty_variant(cx, (ty, layout), index); - Self::from_variant(variant_def, tag, (ty, variant_layout), layout.size, cx) + Self::from_variant( + variant_def, + tag.map(|tag| (tag, index, encoding.unwrap())), + (ty, variant_layout), + layout.size, + cx, + ) }; // We consider three kinds of enums, each demanding a different @@ -345,9 +351,9 @@ pub(crate) mod rustc { Variants::Single { index } => { // `Variants::Single` on enums with variants denotes that // the enum delegates its layout to the variant at `index`. - layout_of_variant(*index) + layout_of_variant(*index, None) } - Variants::Multiple { tag_field, .. } => { + Variants::Multiple { tag, tag_encoding, tag_field, .. } => { // `Variants::Multiple` denotes an enum with multiple // variants. The layout of such an enum is the disjunction // of the layouts of its tagged variants. @@ -359,7 +365,7 @@ pub(crate) mod rustc { let variants = def.discriminants(cx.tcx()).try_fold( Self::uninhabited(), |variants, (idx, ref discriminant)| { - let variant = layout_of_variant(idx)?; + let variant = layout_of_variant(idx, Some(tag_encoding.clone()))?; Result::<Self, Err>::Ok(variants.or(variant)) }, )?; @@ -380,7 +386,7 @@ pub(crate) mod rustc { /// `0`. fn from_variant( def: Def<'tcx>, - tag: Option<ScalarInt>, + tag: Option<(ScalarInt, VariantIdx, TagEncoding<VariantIdx>)>, (ty, layout): (Ty<'tcx>, Layout<'tcx>), total_size: Size, cx: LayoutCx<'tcx, TyCtxt<'tcx>>, @@ -400,9 +406,18 @@ pub(crate) mod rustc { let mut struct_tree = Self::def(def); // If a `tag` is provided, place it at the start of the layout. - if let Some(tag) = tag { - size += tag.size(); - struct_tree = struct_tree.then(Self::from_tag(tag, cx.tcx)); + if let Some((tag, index, encoding)) = &tag { + match encoding { + TagEncoding::Direct => { + size += tag.size(); + } + TagEncoding::Niche { niche_variants, .. } => { + if !niche_variants.contains(index) { + size += tag.size(); + } + } + } + struct_tree = struct_tree.then(Self::from_tag(*tag, cx.tcx)); } // Append the fields, in memory order, to the layout. |