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Implement SMIR generic parameter instantiation #115532

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89 changes: 67 additions & 22 deletions compiler/rustc_smir/src/rustc_smir/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -78,8 +78,8 @@ impl<'tcx> Context for Tables<'tcx> {
impl_trait.stable(self)
}

fn mir_body(&mut self, item: &stable_mir::CrateItem) -> stable_mir::mir::Body {
let def_id = self[item.0];
fn mir_body(&mut self, item: stable_mir::DefId) -> stable_mir::mir::Body {
let def_id = self[item];
let mir = self.tcx.optimized_mir(def_id);
stable_mir::mir::Body {
blocks: mir
Expand All @@ -103,8 +103,13 @@ impl<'tcx> Context for Tables<'tcx> {
}

fn ty_kind(&mut self, ty: crate::stable_mir::ty::Ty) -> TyKind {
let ty = self.types[ty.0];
ty.stable(self)
self.types[ty.0].clone().stable(self)
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why do we need this clone now?

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It's just a Ty<'tcx>, so we should probably copy it.

The reason we need it is that stable takes self by mutable reference, while we immutably borrow from self via the index operations

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Actually I got this wrong. We need to clone the TyKind in case it comes out of a MaybeStable::Stable entry of self.types. Sometimes SMIR creates its own types, and they get interned that way.

}

fn mk_ty(&mut self, kind: TyKind) -> stable_mir::ty::Ty {
let n = self.types.len();
self.types.push(MaybeStable::Stable(kind));
stable_mir::ty::Ty(n)
}

fn generics_of(&mut self, def_id: stable_mir::DefId) -> stable_mir::ty::Generics {
Expand All @@ -128,20 +133,47 @@ impl<'tcx> Context for Tables<'tcx> {
}
}

#[derive(Clone)]
pub enum MaybeStable<S, R> {
Stable(S),
Rustc(R),
}

impl<'tcx, S, R> MaybeStable<S, R> {
fn stable(self, tables: &mut Tables<'tcx>) -> S
where
R: Stable<'tcx, T = S>,
{
match self {
MaybeStable::Stable(s) => s,
MaybeStable::Rustc(r) => r.stable(tables),
}
}
}

impl<S, R: PartialEq> PartialEq<R> for MaybeStable<S, R> {
fn eq(&self, other: &R) -> bool {
match self {
MaybeStable::Stable(_) => false,
MaybeStable::Rustc(r) => r == other,
}
}
}

pub struct Tables<'tcx> {
pub tcx: TyCtxt<'tcx>,
pub def_ids: Vec<DefId>,
pub alloc_ids: Vec<AllocId>,
pub types: Vec<Ty<'tcx>>,
pub types: Vec<MaybeStable<stable_mir::ty::TyKind, Ty<'tcx>>>,
}

impl<'tcx> Tables<'tcx> {
fn intern_ty(&mut self, ty: Ty<'tcx>) -> stable_mir::ty::Ty {
if let Some(id) = self.types.iter().position(|&t| t == ty) {
if let Some(id) = self.types.iter().position(|t| *t == ty) {
return stable_mir::ty::Ty(id);
}
let id = self.types.len();
self.types.push(ty);
self.types.push(MaybeStable::Rustc(ty));
stable_mir::ty::Ty(id)
}
}
Expand Down Expand Up @@ -1097,25 +1129,33 @@ impl<'tcx> Stable<'tcx> for ty::Const<'tcx> {
tables,
))
}
ty::ParamCt(param) => stable_mir::ty::ConstantKind::ParamCt(opaque(&param)),
ty::ParamCt(param) => stable_mir::ty::ConstantKind::Param(param.stable(tables)),
ty::ErrorCt(_) => unreachable!(),
ty::InferCt(_) => unreachable!(),
ty::BoundCt(_, _) => unimplemented!(),
ty::PlaceholderCt(_) => unimplemented!(),
ty::Unevaluated(uv) => {
stable_mir::ty::ConstantKind::Unevaluated(stable_mir::ty::UnevaluatedConst {
ty: tables.intern_ty(self.ty()),
def: tables.const_def(uv.def),
args: uv.args.stable(tables),
promoted: None,
})
}
ty::ExprCt(_) => unimplemented!(),
},
ty: tables.intern_ty(self.ty()),
}
}
}

impl<'tcx> Stable<'tcx> for ty::ParamConst {
type T = stable_mir::ty::ParamConst;
fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
use stable_mir::ty::ParamConst;
ParamConst { index: self.index, name: self.name.to_string() }
}
}

impl<'tcx> Stable<'tcx> for ty::ParamTy {
type T = stable_mir::ty::ParamTy;
fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
Expand Down Expand Up @@ -1184,22 +1224,27 @@ impl<'tcx> Stable<'tcx> for ty::TraitDef {
}

impl<'tcx> Stable<'tcx> for rustc_middle::mir::ConstantKind<'tcx> {
type T = stable_mir::ty::ConstantKind;
type T = stable_mir::ty::Const;

fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
match *self {
ConstantKind::Ty(c) => c.stable(tables).literal,
ConstantKind::Unevaluated(unev_const, ty) => {
stable_mir::ty::ConstantKind::Unevaluated(stable_mir::ty::UnevaluatedConst {
ty: tables.intern_ty(ty),
def: tables.const_def(unev_const.def),
args: unev_const.args.stable(tables),
promoted: unev_const.promoted.map(|u| u.as_u32()),
})
}
ConstantKind::Val(val, ty) => {
stable_mir::ty::ConstantKind::Allocated(alloc::new_allocation(ty, val, tables))
}
ConstantKind::Ty(c) => c.stable(tables),
ConstantKind::Unevaluated(unev_const, ty) => stable_mir::ty::Const {
literal: stable_mir::ty::ConstantKind::Unevaluated(
stable_mir::ty::UnevaluatedConst {
def: tables.const_def(unev_const.def),
args: unev_const.args.stable(tables),
promoted: unev_const.promoted.map(|u| u.as_u32()),
},
),
ty: tables.intern_ty(ty),
},
ConstantKind::Val(val, ty) => stable_mir::ty::Const {
literal: stable_mir::ty::ConstantKind::Allocated(alloc::new_allocation(
ty, val, tables,
)),
ty: tables.intern_ty(ty),
},
}
}
}
Expand Down
230 changes: 230 additions & 0 deletions compiler/rustc_smir/src/stable_mir/fold.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,230 @@
use std::ops::ControlFlow;

use crate::rustc_internal::Opaque;

use super::ty::{
Allocation, Binder, Const, ConstDef, ConstantKind, ExistentialPredicate, FnSig, GenericArgKind,
GenericArgs, Promoted, RigidTy, TermKind, Ty, TyKind, UnevaluatedConst,
};

pub trait Folder: Sized {
type Break;
fn visit_ty(&mut self, ty: &Ty) -> ControlFlow<Self::Break, Ty> {
ty.super_fold(self)
}
fn fold_const(&mut self, c: &Const) -> ControlFlow<Self::Break, Const> {
c.super_fold(self)
}
}

pub trait Foldable: Sized + Clone {
fn fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
self.super_fold(folder)
}
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self>;
}

impl Foldable for Ty {
fn fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
folder.visit_ty(self)
}
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
let mut kind = self.kind();
match &mut kind {
super::ty::TyKind::RigidTy(ty) => *ty = ty.fold(folder)?,
super::ty::TyKind::Alias(_, alias) => alias.args = alias.args.fold(folder)?,
super::ty::TyKind::Param(_) => {}
super::ty::TyKind::Bound(_, _) => {}
}
ControlFlow::Continue(kind.into())
}
}

impl Foldable for Const {
fn fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
folder.fold_const(self)
}
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
let mut this = self.clone();
match &mut this.literal {
super::ty::ConstantKind::Allocated(alloc) => *alloc = alloc.fold(folder)?,
super::ty::ConstantKind::Unevaluated(uv) => *uv = uv.fold(folder)?,
super::ty::ConstantKind::Param(_) => {}
}
this.ty = this.ty.fold(folder)?;
ControlFlow::Continue(this)
}
}

impl Foldable for Opaque {
fn super_fold<V: Folder>(&self, _folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(self.clone())
}
}

impl Foldable for Allocation {
fn super_fold<V: Folder>(&self, _folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(self.clone())
}
}

impl Foldable for UnevaluatedConst {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
let UnevaluatedConst { def, args, promoted } = self;
ControlFlow::Continue(UnevaluatedConst {
def: def.fold(folder)?,
args: args.fold(folder)?,
promoted: promoted.fold(folder)?,
})
}
}

impl Foldable for ConstDef {
fn super_fold<V: Folder>(&self, _folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(self.clone())
}
}

impl<T: Foldable> Foldable for Option<T> {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(match self {
Some(val) => Some(val.fold(folder)?),
None => None,
})
}
}

impl Foldable for Promoted {
fn super_fold<V: Folder>(&self, _folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(self.clone())
}
}

impl Foldable for GenericArgs {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(GenericArgs(self.0.fold(folder)?))
}
}

impl Foldable for GenericArgKind {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
let mut this = self.clone();
match &mut this {
GenericArgKind::Lifetime(lt) => *lt = lt.fold(folder)?,
GenericArgKind::Type(t) => *t = t.fold(folder)?,
GenericArgKind::Const(c) => *c = c.fold(folder)?,
}
ControlFlow::Continue(this)
}
}

impl Foldable for RigidTy {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
let mut this = self.clone();
match &mut this {
RigidTy::Bool
| RigidTy::Char
| RigidTy::Int(_)
| RigidTy::Uint(_)
| RigidTy::Float(_)
| RigidTy::Never
| RigidTy::Foreign(_)
| RigidTy::Str => {}
RigidTy::Array(t, c) => {
*t = t.fold(folder)?;
*c = c.fold(folder)?;
}
RigidTy::Slice(inner) => *inner = inner.fold(folder)?,
RigidTy::RawPtr(ty, _) => *ty = ty.fold(folder)?,
RigidTy::Ref(_, ty, _) => *ty = ty.fold(folder)?,
RigidTy::FnDef(_, args) => *args = args.fold(folder)?,
RigidTy::FnPtr(sig) => *sig = sig.fold(folder)?,
RigidTy::Closure(_, args) => *args = args.fold(folder)?,
RigidTy::Generator(_, args, _) => *args = args.fold(folder)?,
RigidTy::Dynamic(pred, r, _) => {
*pred = pred.fold(folder)?;
*r = r.fold(folder)?;
}
RigidTy::Tuple(fields) => *fields = fields.fold(folder)?,
RigidTy::Adt(_, args) => *args = args.fold(folder)?,
}
ControlFlow::Continue(this)
}
}

impl<T: Foldable> Foldable for Vec<T> {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
let mut this = self.clone();
for arg in &mut this {
*arg = arg.fold(folder)?;
}
ControlFlow::Continue(this)
}
}

impl<T: Foldable> Foldable for Binder<T> {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(Self {
value: self.value.fold(folder)?,
bound_vars: self.bound_vars.clone(),
})
}
}

impl Foldable for ExistentialPredicate {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
let mut this = self.clone();
match &mut this {
ExistentialPredicate::Trait(tr) => tr.generic_args = tr.generic_args.fold(folder)?,
ExistentialPredicate::Projection(p) => {
p.term = p.term.fold(folder)?;
p.generic_args = p.generic_args.fold(folder)?;
}
ExistentialPredicate::AutoTrait(_) => {}
}
ControlFlow::Continue(this)
}
}

impl Foldable for TermKind {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(match self {
TermKind::Type(t) => TermKind::Type(t.fold(folder)?),
TermKind::Const(c) => TermKind::Const(c.fold(folder)?),
})
}
}

impl Foldable for FnSig {
fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
ControlFlow::Continue(Self {
inputs_and_output: self.inputs_and_output.fold(folder)?,
c_variadic: self.c_variadic,
unsafety: self.unsafety,
abi: self.abi.clone(),
})
}
}

pub enum Never {}

/// In order to instantiate a `Foldable`'s generic parameters with specific arguments,
/// `GenericArgs` can be used as a `Folder` that replaces all mentions of generic params
/// with the entries in its list.
impl Folder for GenericArgs {
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type Break = Never;

fn visit_ty(&mut self, ty: &Ty) -> ControlFlow<Self::Break, Ty> {
ControlFlow::Continue(match ty.kind() {
TyKind::Param(p) => self[p],
_ => *ty,
})
}

fn fold_const(&mut self, c: &Const) -> ControlFlow<Self::Break, Const> {
ControlFlow::Continue(match &c.literal {
ConstantKind::Param(p) => self[p.clone()].clone(),
_ => c.clone(),
})
}
}
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