rustc_smir/rustc_smir/
mod.rs

1//! Module that implements what will become the rustc side of Stable MIR.
2
3//! This module is responsible for building Stable MIR components from internal components.
4//!
5//! This module is not intended to be invoked directly by users. It will eventually
6//! become the public API of rustc that will be invoked by the `stable_mir` crate.
7//!
8//! For now, we are developing everything inside `rustc`, thus, we keep this module private.
9
10use std::ops::RangeInclusive;
11
12use rustc_data_structures::PointeeSized;
13use rustc_hir::def::DefKind;
14use rustc_middle::mir;
15use rustc_middle::mir::interpret::AllocId;
16use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
17use rustc_span::def_id::{CrateNum, DefId, LOCAL_CRATE};
18use stable_mir::abi::Layout;
19use stable_mir::mir::mono::{InstanceDef, StaticDef};
20use stable_mir::ty::{FnDef, MirConstId, Span, TyConstId};
21use stable_mir::{CtorKind, ItemKind};
22use tracing::debug;
23
24use crate::rustc_internal::IndexMap;
25use crate::stable_mir;
26
27mod alloc;
28mod builder;
29pub mod context;
30mod convert;
31
32pub struct Tables<'tcx> {
33    pub(crate) tcx: TyCtxt<'tcx>,
34    pub(crate) def_ids: IndexMap<DefId, stable_mir::DefId>,
35    pub(crate) alloc_ids: IndexMap<AllocId, stable_mir::mir::alloc::AllocId>,
36    pub(crate) spans: IndexMap<rustc_span::Span, Span>,
37    pub(crate) types: IndexMap<Ty<'tcx>, stable_mir::ty::Ty>,
38    pub(crate) instances: IndexMap<ty::Instance<'tcx>, InstanceDef>,
39    pub(crate) ty_consts: IndexMap<ty::Const<'tcx>, TyConstId>,
40    pub(crate) mir_consts: IndexMap<mir::Const<'tcx>, MirConstId>,
41    pub(crate) layouts: IndexMap<rustc_abi::Layout<'tcx>, Layout>,
42}
43
44impl<'tcx> Tables<'tcx> {
45    pub(crate) fn intern_ty(&mut self, ty: Ty<'tcx>) -> stable_mir::ty::Ty {
46        self.types.create_or_fetch(ty)
47    }
48
49    pub(crate) fn intern_ty_const(&mut self, ct: ty::Const<'tcx>) -> TyConstId {
50        self.ty_consts.create_or_fetch(ct)
51    }
52
53    pub(crate) fn intern_mir_const(&mut self, constant: mir::Const<'tcx>) -> MirConstId {
54        self.mir_consts.create_or_fetch(constant)
55    }
56
57    /// Return whether the instance as a body available.
58    ///
59    /// Items and intrinsics may have a body available from its definition.
60    /// Shims body may be generated depending on their type.
61    pub(crate) fn instance_has_body(&self, instance: Instance<'tcx>) -> bool {
62        let def_id = instance.def_id();
63        self.item_has_body(def_id)
64            || !matches!(
65                instance.def,
66                ty::InstanceKind::Virtual(..)
67                    | ty::InstanceKind::Intrinsic(..)
68                    | ty::InstanceKind::Item(..)
69            )
70    }
71
72    /// Return whether the item has a body defined by the user.
73    ///
74    /// Note that intrinsics may have a placeholder body that shouldn't be used in practice.
75    /// In StableMIR, we handle this case as if the body is not available.
76    pub(crate) fn item_has_body(&self, def_id: DefId) -> bool {
77        let must_override = if let Some(intrinsic) = self.tcx.intrinsic(def_id) {
78            intrinsic.must_be_overridden
79        } else {
80            false
81        };
82        !must_override && self.tcx.is_mir_available(def_id)
83    }
84
85    fn to_fn_def(&mut self, def_id: DefId) -> Option<FnDef> {
86        if matches!(self.tcx.def_kind(def_id), DefKind::Fn | DefKind::AssocFn) {
87            Some(self.fn_def(def_id))
88        } else {
89            None
90        }
91    }
92
93    fn to_static(&mut self, def_id: DefId) -> Option<StaticDef> {
94        matches!(self.tcx.def_kind(def_id), DefKind::Static { .. }).then(|| self.static_def(def_id))
95    }
96}
97
98/// Iterate over the definitions of the given crate.
99pub(crate) fn filter_def_ids<F, T>(tcx: TyCtxt<'_>, krate: CrateNum, mut func: F) -> Vec<T>
100where
101    F: FnMut(DefId) -> Option<T>,
102{
103    if krate == LOCAL_CRATE {
104        tcx.iter_local_def_id().filter_map(|did| func(did.to_def_id())).collect()
105    } else {
106        let num_definitions = tcx.num_extern_def_ids(krate);
107        (0..num_definitions)
108            .filter_map(move |i| {
109                let def_id = DefId { krate, index: rustc_span::def_id::DefIndex::from_usize(i) };
110                func(def_id)
111            })
112            .collect()
113    }
114}
115
116/// Build a stable mir crate from a given crate number.
117pub(crate) fn smir_crate(tcx: TyCtxt<'_>, crate_num: CrateNum) -> stable_mir::Crate {
118    let crate_name = tcx.crate_name(crate_num).to_string();
119    let is_local = crate_num == LOCAL_CRATE;
120    debug!(?crate_name, ?crate_num, "smir_crate");
121    stable_mir::Crate { id: crate_num.into(), name: crate_name, is_local }
122}
123
124pub(crate) fn new_item_kind(kind: DefKind) -> ItemKind {
125    match kind {
126        DefKind::Mod
127        | DefKind::Struct
128        | DefKind::Union
129        | DefKind::Enum
130        | DefKind::Variant
131        | DefKind::Trait
132        | DefKind::TyAlias
133        | DefKind::ForeignTy
134        | DefKind::TraitAlias
135        | DefKind::AssocTy
136        | DefKind::TyParam
137        | DefKind::ConstParam
138        | DefKind::Macro(_)
139        | DefKind::ExternCrate
140        | DefKind::Use
141        | DefKind::ForeignMod
142        | DefKind::OpaqueTy
143        | DefKind::Field
144        | DefKind::LifetimeParam
145        | DefKind::Impl { .. }
146        | DefKind::GlobalAsm => {
147            unreachable!("Not a valid item kind: {kind:?}");
148        }
149        DefKind::Closure | DefKind::AssocFn | DefKind::Fn | DefKind::SyntheticCoroutineBody => {
150            ItemKind::Fn
151        }
152        DefKind::Const | DefKind::InlineConst | DefKind::AssocConst | DefKind::AnonConst => {
153            ItemKind::Const
154        }
155        DefKind::Static { .. } => ItemKind::Static,
156        DefKind::Ctor(_, rustc_hir::def::CtorKind::Const) => ItemKind::Ctor(CtorKind::Const),
157        DefKind::Ctor(_, rustc_hir::def::CtorKind::Fn) => ItemKind::Ctor(CtorKind::Fn),
158    }
159}
160
161/// Trait used to convert between an internal MIR type to a Stable MIR type.
162pub trait Stable<'cx>: PointeeSized {
163    /// The stable representation of the type implementing Stable.
164    type T;
165    /// Converts an object to the equivalent Stable MIR representation.
166    fn stable(&self, tables: &mut Tables<'_>) -> Self::T;
167}
168
169impl<'tcx, T> Stable<'tcx> for &T
170where
171    T: Stable<'tcx>,
172{
173    type T = T::T;
174
175    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
176        (*self).stable(tables)
177    }
178}
179
180impl<'tcx, T> Stable<'tcx> for Option<T>
181where
182    T: Stable<'tcx>,
183{
184    type T = Option<T::T>;
185
186    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
187        self.as_ref().map(|value| value.stable(tables))
188    }
189}
190
191impl<'tcx, T, E> Stable<'tcx> for Result<T, E>
192where
193    T: Stable<'tcx>,
194    E: Stable<'tcx>,
195{
196    type T = Result<T::T, E::T>;
197
198    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
199        match self {
200            Ok(val) => Ok(val.stable(tables)),
201            Err(error) => Err(error.stable(tables)),
202        }
203    }
204}
205
206impl<'tcx, T> Stable<'tcx> for &[T]
207where
208    T: Stable<'tcx>,
209{
210    type T = Vec<T::T>;
211    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
212        self.iter().map(|e| e.stable(tables)).collect()
213    }
214}
215
216impl<'tcx, T, U> Stable<'tcx> for (T, U)
217where
218    T: Stable<'tcx>,
219    U: Stable<'tcx>,
220{
221    type T = (T::T, U::T);
222    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
223        (self.0.stable(tables), self.1.stable(tables))
224    }
225}
226
227impl<'tcx, T> Stable<'tcx> for RangeInclusive<T>
228where
229    T: Stable<'tcx>,
230{
231    type T = RangeInclusive<T::T>;
232    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
233        RangeInclusive::new(self.start().stable(tables), self.end().stable(tables))
234    }
235}
rustc_smir/rustc_smir/mod.rs

rustc_smir/rustc_smir/
mod.rs
