bjoernager/rust
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Store a DefId instead of an AdtDef in AggregateKind::Adt

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The `AggregateKind` enum ends up in the final mir `Body`. Currently,
any changes to `AdtDef` (regardless of how significant they are)
will legitimately cause the overall result of `optimized_mir` to change,
invalidating any codegen re-use involving that mir.

This will get worse once we start hashing the `Span` inside `FieldDef`
(which is itself contained in `AdtDef`).

To try to reduce these kinds of invalidations, this commit changes
`AggregateKind::Adt` to store just the `DefId`, instead of the full
`AdtDef`. This allows the result of `optimized_mir` to be unchanged
if the `AdtDef` changes in a way that doesn't actually affect any
of the MIR we build.
This commit is contained in:
Aaron Hill 2021-12-22 14:35:17 -05:00
parent e100ec5bc7
commit cac431ba75
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GPG key ID: B4087E510E98B164
11 changed files with 32 additions and 31 deletions
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4
compiler/rustc_codegen_ssa/src/mir/rvalue.rs
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@ -112,9 +112,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
mir::Rvalue::Aggregate(ref kind, ref operands) => {
let (dest, active_field_index) = match **kind {
mir::AggregateKind::Adt(adt_def, variant_index, _, _, active_field_index) => {
mir::AggregateKind::Adt(adt_did, variant_index, _, _, active_field_index) => {
dest.codegen_set_discr(&mut bx, variant_index);
if adt_def.is_enum() {
if bx.tcx().adt_def(adt_did).is_enum() {
(dest.project_downcast(&mut bx, variant_index), active_field_index)
} else {
(dest, active_field_index)