Rollup merge of #107756 - RalfJung:miri-out-of-addresses, r=oli-obk

[rust.git] / compiler / rustc_const_eval / src / interpret / place.rs

diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index 86786d812667f915927a04d142058b9e10393ce9..038282e2161e6637891d2cde59fe2e766e40b189 100644 (file)
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -7,8 +7,8 @@
 use rustc_ast::Mutability;
 use rustc_middle::mir;
 use rustc_middle::ty;
-use rustc_middle::ty::layout::{LayoutOf, PrimitiveExt, TyAndLayout};
-use rustc_target::abi::{self, Abi, Align, HasDataLayout, Size, TagEncoding, VariantIdx};
+use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
+use rustc_target::abi::{self, Abi, Align, HasDataLayout, Size, VariantIdx};
 
 use super::{
     alloc_range, mir_assign_valid_types, AllocId, AllocRef, AllocRefMut, CheckInAllocMsg,
@@ -767,87 +767,8 @@ pub fn allocate_str(
         Ok(MPlaceTy { mplace, layout, align: layout.align.abi })
     }
 
-    /// Writes the discriminant of the given variant.
-    #[instrument(skip(self), level = "debug")]
-    pub fn write_discriminant(
-        &mut self,
-        variant_index: VariantIdx,
-        dest: &PlaceTy<'tcx, M::Provenance>,
-    ) -> InterpResult<'tcx> {
-        // Layout computation excludes uninhabited variants from consideration
-        // therefore there's no way to represent those variants in the given layout.
-        // Essentially, uninhabited variants do not have a tag that corresponds to their
-        // discriminant, so we cannot do anything here.
-        // When evaluating we will always error before even getting here, but ConstProp 'executes'
-        // dead code, so we cannot ICE here.
-        if dest.layout.for_variant(self, variant_index).abi.is_uninhabited() {
-            throw_ub!(UninhabitedEnumVariantWritten)
-        }
-
-        match dest.layout.variants {
-            abi::Variants::Single { index } => {
-                assert_eq!(index, variant_index);
-            }
-            abi::Variants::Multiple {
-                tag_encoding: TagEncoding::Direct,
-                tag: tag_layout,
-                tag_field,
-                ..
-            } => {
-                // No need to validate that the discriminant here because the
-                // `TyAndLayout::for_variant()` call earlier already checks the variant is valid.
-
-                let discr_val =
-                    dest.layout.ty.discriminant_for_variant(*self.tcx, variant_index).unwrap().val;
-
-                // raw discriminants for enums are isize or bigger during
-                // their computation, but the in-memory tag is the smallest possible
-                // representation
-                let size = tag_layout.size(self);
-                let tag_val = size.truncate(discr_val);
-
-                let tag_dest = self.place_field(dest, tag_field)?;
-                self.write_scalar(Scalar::from_uint(tag_val, size), &tag_dest)?;
-            }
-            abi::Variants::Multiple {
-                tag_encoding:
-                    TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start },
-                tag: tag_layout,
-                tag_field,
-                ..
-            } => {
-                // No need to validate that the discriminant here because the
-                // `TyAndLayout::for_variant()` call earlier already checks the variant is valid.
-
-                if variant_index != untagged_variant {
-                    let variants_start = niche_variants.start().as_u32();
-                    let variant_index_relative = variant_index
-                        .as_u32()
-                        .checked_sub(variants_start)
-                        .expect("overflow computing relative variant idx");
-                    // We need to use machine arithmetic when taking into account `niche_start`:
-                    // tag_val = variant_index_relative + niche_start_val
-                    let tag_layout = self.layout_of(tag_layout.primitive().to_int_ty(*self.tcx))?;
-                    let niche_start_val = ImmTy::from_uint(niche_start, tag_layout);
-                    let variant_index_relative_val =
-                        ImmTy::from_uint(variant_index_relative, tag_layout);
-                    let tag_val = self.binary_op(
-                        mir::BinOp::Add,
-                        &variant_index_relative_val,
-                        &niche_start_val,
-                    )?;
-                    // Write result.
-                    let niche_dest = self.place_field(dest, tag_field)?;
-                    self.write_immediate(*tag_val, &niche_dest)?;
-                }
-            }
-        }
-
-        Ok(())
-    }
-
-    /// Writes the discriminant of the given variant.
-    #[instrument(skip(self), level = "debug")]
+    /// Writes the aggregate to the destination.
+    #[instrument(skip(self), level = "trace")]
     pub fn write_aggregate(
         &mut self,
         kind: &mir::AggregateKind<'tcx>,