bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/mir/eval.rs')
-rw-r--r--crates/hir-ty/src/mir/eval.rs107
1 files changed, 56 insertions, 51 deletions
diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs
index 0c7669cd54..78961e1982 100644
--- a/crates/hir-ty/src/mir/eval.rs
+++ b/crates/hir-ty/src/mir/eval.rs
@@ -1049,57 +1049,8 @@ impl Evaluator<'_> {
Rvalue::Discriminant(p) => {
let ty = self.place_ty(p, locals)?;
let bytes = self.eval_place(p, locals)?.get(&self)?;
- let layout = self.layout(&ty)?;
- let enum_id = 'b: {
- match ty.kind(Interner) {
- TyKind::Adt(e, _) => match e.0 {
- AdtId::EnumId(e) => break 'b e,
- _ => (),
- },
- _ => (),
- }
- return Ok(Owned(0u128.to_le_bytes().to_vec()));
- };
- match &layout.variants {
- Variants::Single { index } => {
- let r = self.const_eval_discriminant(EnumVariantId {
- parent: enum_id,
- local_id: index.0,
- })?;
- Owned(r.to_le_bytes().to_vec())
- }
- Variants::Multiple { tag, tag_encoding, variants, .. } => {
- let Some(target_data_layout) = self.db.target_data_layout(self.crate_id) else {
- not_supported!("missing target data layout");
- };
- let size = tag.size(&*target_data_layout).bytes_usize();
- let offset = layout.fields.offset(0).bytes_usize(); // The only field on enum variants is the tag field
- match tag_encoding {
- TagEncoding::Direct => {
- let tag = &bytes[offset..offset + size];
- Owned(pad16(tag, false).to_vec())
- }
- TagEncoding::Niche { untagged_variant, niche_start, .. } => {
- let tag = &bytes[offset..offset + size];
- let candidate_tag = i128::from_le_bytes(pad16(tag, false))
- .wrapping_sub(*niche_start as i128)
- as usize;
- let variant = variants
- .iter_enumerated()
- .map(|(x, _)| x)
- .filter(|x| x != untagged_variant)
- .nth(candidate_tag)
- .unwrap_or(*untagged_variant)
- .0;
- let result = self.const_eval_discriminant(EnumVariantId {
- parent: enum_id,
- local_id: variant,
- })?;
- Owned(result.to_le_bytes().to_vec())
- }
- }
- }
- }
+ let result = self.compute_discriminant(ty, bytes)?;
+ Owned(result.to_le_bytes().to_vec())
}
Rvalue::Repeat(x, len) => {
let len = match try_const_usize(self.db, &len) {
@@ -1229,6 +1180,60 @@ impl Evaluator<'_> {
})
}
+ fn compute_discriminant(&self, ty: Ty, bytes: &[u8]) -> Result<i128> {
+ let layout = self.layout(&ty)?;
+ let enum_id = 'b: {
+ match ty.kind(Interner) {
+ TyKind::Adt(e, _) => match e.0 {
+ AdtId::EnumId(e) => break 'b e,
+ _ => (),
+ },
+ _ => (),
+ }
+ return Ok(0);
+ };
+ match &layout.variants {
+ Variants::Single { index } => {
+ let r = self.const_eval_discriminant(EnumVariantId {
+ parent: enum_id,
+ local_id: index.0,
+ })?;
+ Ok(r)
+ }
+ Variants::Multiple { tag, tag_encoding, variants, .. } => {
+ let Some(target_data_layout) = self.db.target_data_layout(self.crate_id) else {
+ not_supported!("missing target data layout");
+ };
+ let size = tag.size(&*target_data_layout).bytes_usize();
+ let offset = layout.fields.offset(0).bytes_usize(); // The only field on enum variants is the tag field
+ match tag_encoding {
+ TagEncoding::Direct => {
+ let tag = &bytes[offset..offset + size];
+ Ok(i128::from_le_bytes(pad16(tag, false)))
+ }
+ TagEncoding::Niche { untagged_variant, niche_start, .. } => {
+ let tag = &bytes[offset..offset + size];
+ let candidate_tag = i128::from_le_bytes(pad16(tag, false))
+ .wrapping_sub(*niche_start as i128)
+ as usize;
+ let variant = variants
+ .iter_enumerated()
+ .map(|(x, _)| x)
+ .filter(|x| x != untagged_variant)
+ .nth(candidate_tag)
+ .unwrap_or(*untagged_variant)
+ .0;
+ let result = self.const_eval_discriminant(EnumVariantId {
+ parent: enum_id,
+ local_id: variant,
+ })?;
+ Ok(result)
+ }
+ }
+ }
+ }
+ }
+
fn coerce_unsized_look_through_fields<T>(
&self,
ty: &Ty,