charon_driver/translate/
translate_types.rs

1use itertools::Itertools;
2use rustc_middle::ty;
3use rustc_span::sym;
4
5use super::translate_ctx::*;
6use crate::hax::{self, UnderOwnerState};
7use crate::hax::{HasOwner, Visibility};
8use charon_lib::ast::*;
9use charon_lib::ids::IndexVec;
10
11impl<'tcx, 'ctx> ItemTransCtx<'tcx, 'ctx> {
12    /// Translate an erased region. If we're inside a body, this will return a fresh body region
13    /// instead.
14    pub(crate) fn translate_erased_region(&mut self) -> Region {
15        if let Some(v) = &mut self.lifetime_freshener {
16            Region::Body(v.push(()))
17        } else {
18            Region::Erased
19        }
20    }
21
22    /// Erase a region binder by supplying erased lifetimes (or fresh body lifetimes) for all its
23    /// arguments.
24    pub(crate) fn erase_region_binder<T: TyVisitable>(&mut self, b: RegionBinder<T>) -> T {
25        let regions = b
26            .regions
27            .map_ref_indexed(|_, _| self.translate_erased_region());
28        b.apply(regions)
29    }
30
31    // Translate a region
32    pub(crate) fn translate_region(
33        &mut self,
34        span: Span,
35        region: &hax::Region,
36    ) -> Result<Region, Error> {
37        use crate::hax::RegionKind::*;
38        match &region.kind {
39            ReErased => Ok(self.translate_erased_region()),
40            ReStatic => Ok(Region::Static),
41            ReBound(hax::BoundVarIndexKind::Bound(id), br) => {
42                Ok(match self.lookup_bound_region(span, *id, br.var) {
43                    Ok(var) => Region::Var(var),
44                    Err(_) => Region::Erased,
45                })
46            }
47            ReEarlyParam(region) => Ok(match self.lookup_early_region(span, region) {
48                Ok(var) => Region::Var(var),
49                Err(_) => Region::Erased,
50            }),
51            ReLateParam(region) => Ok(Region::Var(self.lookup_late_param_region(span, region)?)),
52            ReVar(..) | RePlaceholder(..) => {
53                // Shouldn't exist outside of type inference.
54                raise_error!(
55                    self,
56                    span,
57                    "Should not exist outside of type inference: {region:?}"
58                )
59            }
60            ReBound(..) | ReError(..) => {
61                raise_error!(self, span, "Unexpected region kind: {region:?}")
62            }
63        }
64    }
65
66    pub(crate) fn translate_hax_int_ty(int_ty: &hax::IntTy) -> IntTy {
67        match int_ty {
68            hax::IntTy::Isize => IntTy::Isize,
69            hax::IntTy::I8 => IntTy::I8,
70            hax::IntTy::I16 => IntTy::I16,
71            hax::IntTy::I32 => IntTy::I32,
72            hax::IntTy::I64 => IntTy::I64,
73            hax::IntTy::I128 => IntTy::I128,
74        }
75    }
76
77    pub(crate) fn translate_hax_uint_ty(uint_ty: &hax::UintTy) -> UIntTy {
78        use crate::hax::UintTy;
79        match uint_ty {
80            UintTy::Usize => UIntTy::Usize,
81            UintTy::U8 => UIntTy::U8,
82            UintTy::U16 => UIntTy::U16,
83            UintTy::U32 => UIntTy::U32,
84            UintTy::U64 => UIntTy::U64,
85            UintTy::U128 => UIntTy::U128,
86        }
87    }
88
89    /// Translate a Ty.
90    ///
91    /// Typically used in this module to translate the fields of a structure/
92    /// enumeration definition, or later to translate the type of a variable.
93    ///
94    /// Note that we take as parameter a function to translate regions, because
95    /// regions can be translated in several manners (non-erased region or erased
96    /// regions), in which case the return type is different.
97    #[tracing::instrument(skip(self, span))]
98    pub(crate) fn translate_ty(&mut self, span: Span, hax_ty: &hax::Ty) -> Result<Ty, Error> {
99        let mut ty = if let Some(ty) = self
100            .innermost_binder()
101            .type_trans_cache
102            .get(hax_ty)
103            .cloned()
104        {
105            ty
106        } else {
107            let ty = self
108                .translate_ty_inner(span, hax_ty)
109                .unwrap_or_else(|e| TyKind::Error(e.msg).into_ty());
110            self.innermost_binder_mut()
111                .type_trans_cache
112                .insert(hax_ty.clone(), ty.clone());
113            ty
114        };
115        if let Some(v) = &mut self.lifetime_freshener {
116            // We might be reusing a value from cache: we must refresh the erased & body regions.
117            ty = ty.replace_erased_regions(|| Region::Body(v.push(())));
118        }
119        Ok(ty)
120    }
121
122    fn translate_ty_inner(&mut self, span: Span, ty: &hax::Ty) -> Result<Ty, Error> {
123        trace!("{:?}", ty);
124        let kind = match ty.kind() {
125            hax::TyKind::Bool => TyKind::Literal(LiteralTy::Bool),
126            hax::TyKind::Char => TyKind::Literal(LiteralTy::Char),
127            hax::TyKind::Int(int_ty) => {
128                TyKind::Literal(LiteralTy::Int(Self::translate_hax_int_ty(int_ty)))
129            }
130            hax::TyKind::Uint(uint_ty) => {
131                TyKind::Literal(LiteralTy::UInt(Self::translate_hax_uint_ty(uint_ty)))
132            }
133            hax::TyKind::Float(float_ty) => {
134                use crate::hax::FloatTy;
135                TyKind::Literal(LiteralTy::Float(match float_ty {
136                    FloatTy::F16 => types::FloatTy::F16,
137                    FloatTy::F32 => types::FloatTy::F32,
138                    FloatTy::F64 => types::FloatTy::F64,
139                    FloatTy::F128 => types::FloatTy::F128,
140                }))
141            }
142            hax::TyKind::Never => TyKind::Never,
143
144            hax::TyKind::Alias(alias) => match &alias.kind {
145                hax::AliasKind::Projection(item) => {
146                    let trait_ref = self.translate_trait_proof(
147                        span,
148                        item.in_trait
149                            .as_ref()
150                            .expect("projection without a trait_ref?"),
151                    )?;
152                    let assoc_type_id =
153                        self.translate_assoc_type_id(trait_ref.trait_id(), &item.def_id)?;
154                    let generics =
155                        self.translate_generic_args(span, &item.generic_args, &item.trait_proofs)?;
156                    TyKind::TraitType(trait_ref, assoc_type_id, generics)
157                }
158                hax::AliasKind::Opaque { hidden_ty, .. } => {
159                    return self.translate_ty(span, hidden_ty);
160                }
161                _ => {
162                    raise_error!(self, span, "Unsupported alias type: {:?}", alias.kind)
163                }
164            },
165
166            hax::TyKind::Adt(item) => {
167                let tref = self.translate_type_decl_ref(span, item)?;
168                TyKind::Adt(tref)
169            }
170            hax::TyKind::Str => {
171                let tref = TypeDeclRef::new(TypeId::Builtin(BuiltinTy::Str), GenericArgs::empty());
172                TyKind::Adt(tref)
173            }
174            hax::TyKind::Array(item_ref) => {
175                let mut args = self.translate_generic_args(span, &item_ref.generic_args, &[])?;
176                assert!(args.types.len() == 1 && args.const_generics.len() == 1);
177                TyKind::Array(
178                    args.types.pop().unwrap(),
179                    Box::new(args.const_generics.pop().unwrap()),
180                )
181            }
182            hax::TyKind::Pat(ty, pat) => {
183                let ty = self.translate_ty(span, ty)?;
184                let pat = self.translate_pattern(span, pat)?;
185                TyKind::Pattern(ty, pat)
186            }
187            hax::TyKind::Slice(item_ref) => {
188                let mut args = self.translate_generic_args(span, &item_ref.generic_args, &[])?;
189                assert!(args.types.len() == 1);
190                TyKind::Slice(args.types.pop().unwrap())
191            }
192            hax::TyKind::Tuple(item_ref) => {
193                let args = self.translate_generic_args(span, &item_ref.generic_args, &[])?;
194                let tref = TypeDeclRef::new(TypeId::Tuple, args);
195                TyKind::Adt(tref)
196            }
197            hax::TyKind::Ref(region, ty, mutability) => {
198                trace!("Ref");
199
200                let region = self.translate_region(span, region)?;
201                let ty = self.translate_ty(span, ty)?;
202                let kind = if mutability.is_mut() {
203                    RefKind::Mut
204                } else {
205                    RefKind::Shared
206                };
207                TyKind::Ref(region, ty, kind)
208            }
209            hax::TyKind::RawPtr(ty, mutbl) => {
210                trace!("RawPtr: {:?}", (ty, mutbl));
211                let ty = self.translate_ty(span, ty)?;
212                let kind = if mutbl.is_mut() {
213                    RefKind::Mut
214                } else {
215                    RefKind::Shared
216                };
217                TyKind::RawPtr(ty, kind)
218            }
219
220            hax::TyKind::Param(param) => {
221                // A type parameter, for example `T` in `fn f<T>(x : T) {}`.
222                // Note that this type parameter may actually have been
223                // instantiated (in our environment, we may map it to another
224                // type): we just have to look it up.
225                // Note that if we are using this function to translate a field
226                // type in a type definition, it should actually map to a type
227                // parameter.
228                match self.lookup_type_var(span, param) {
229                    Ok(var) => TyKind::TypeVar(var),
230                    Err(err) => TyKind::Error(err.msg),
231                }
232            }
233
234            hax::TyKind::Foreign(item) => {
235                let tref = self.translate_type_decl_ref(span, item)?;
236                TyKind::Adt(tref)
237            }
238
239            hax::TyKind::Arrow(sig) => {
240                trace!("Arrow");
241                trace!("bound vars: {:?}", sig.bound_vars);
242                let sig = self.translate_poly_fun_sig(span, sig)?;
243                TyKind::FnPtr(sig)
244            }
245            hax::TyKind::FnDef { item, .. } => {
246                let fnref = self.translate_bound_fn_ptr(span, item, TransItemSourceKind::Fun)?;
247                TyKind::FnDef(fnref)
248            }
249            hax::TyKind::Closure(args) => {
250                let tref = self.translate_closure_type_ref(span, args)?;
251                TyKind::Adt(tref)
252            }
253
254            hax::TyKind::Dynamic(dyn_binder, region) => {
255                // self.check_no_monomorphize(span)?;
256                // Translate the region outside the binder.
257                let region = self.translate_region(span, region)?;
258
259                let binder = self.translate_dyn_binder(span, dyn_binder, |ctx, ty, ()| {
260                    let region = region.move_under_binder();
261                    ctx.innermost_binder_mut()
262                        .params
263                        .types_outlive
264                        .push(RegionBinder::empty(OutlivesPred(ty.clone(), region)));
265                    Ok(ty)
266                })?;
267
268                if let hax::ClauseKind::Trait(trait_predicate) = dyn_binder.predicates.predicates[0]
269                    .clause
270                    .kind
271                    .hax_skip_binder_ref()
272                {
273                    // TODO(dyn): for now, we consider traits with associated types to not be dyn
274                    // compatible because we don't know how to handle them; for these we skip
275                    // translating the vtable.
276                    if self.trait_is_dyn_compatible(&trait_predicate.trait_ref.def_id)? {
277                        // Ensure the vtable type is translated. The first predicate is the one that
278                        // can have methods, i.e. a vtable.
279                        if self.monomorphize() {
280                            let item_src = TransItemSource::monomorphic_trait(
281                                &trait_predicate.trait_ref.def_id,
282                                TransItemSourceKind::VTable,
283                            );
284                            let _: TypeDeclId = self.register_and_enqueue(span, item_src);
285                        } else {
286                            let _: TypeDeclId = self.register_item(
287                                span,
288                                &trait_predicate.trait_ref,
289                                TransItemSourceKind::VTable,
290                            );
291                        }
292                    }
293                }
294                TyKind::DynTrait(DynPredicate { binder })
295            }
296
297            hax::TyKind::Infer(_) => {
298                raise_error!(self, span, "Unsupported type: infer type")
299            }
300            hax::TyKind::Coroutine(..) => {
301                raise_error!(self, span, "Coroutine types are not supported yet")
302            }
303            hax::TyKind::Bound(_, _) => {
304                raise_error!(self, span, "Unexpected type kind: bound")
305            }
306            hax::TyKind::Placeholder(_) => {
307                raise_error!(self, span, "Unsupported type: placeholder")
308            }
309
310            hax::TyKind::Error => {
311                raise_error!(self, span, "Type checking error")
312            }
313            hax::TyKind::Todo(s) => {
314                raise_error!(self, span, "Unsupported type: {:?}", s)
315            }
316        };
317        Ok(kind.into_ty())
318    }
319
320    pub fn translate_pattern(
321        &mut self,
322        span: Span,
323        pat: &hax::Pattern,
324    ) -> Result<TypePattern, Error> {
325        Ok(match pat {
326            hax::Pattern::Range { start, end } => TypePattern::Range(
327                Box::new(self.translate_constant_expr(span, start)?),
328                Box::new(self.translate_constant_expr(span, end)?),
329            ),
330            hax::Pattern::Or(patterns) => TypePattern::OrPattern(
331                patterns
332                    .iter()
333                    .map(|pat| self.translate_pattern(span, pat))
334                    .try_collect()?,
335            ),
336            hax::Pattern::NotNull => TypePattern::NotNull,
337        })
338    }
339
340    pub(crate) fn translate_rustc_ty(
341        &mut self,
342        span: Span,
343        ty: &ty::Ty<'tcx>,
344    ) -> Result<Ty, Error> {
345        let ty = self.t_ctx.catch_sinto(&self.hax_state, span, ty)?;
346        self.translate_ty(span, &ty)
347    }
348
349    pub fn translate_poly_fun_sig(
350        &mut self,
351        span: Span,
352        sig: &hax::Binder<hax::TyFnSig>,
353    ) -> Result<RegionBinder<FunSig>, Error> {
354        self.translate_region_binder(span, sig, |ctx, sig| ctx.translate_fun_sig(span, sig))
355    }
356    pub fn translate_fun_sig(&mut self, span: Span, sig: &hax::TyFnSig) -> Result<FunSig, Error> {
357        let inputs = sig
358            .inputs
359            .iter()
360            .map(|x| self.translate_ty(span, x))
361            .try_collect()?;
362        let output = self.translate_ty(span, &sig.output)?;
363        Ok(FunSig {
364            is_unsafe: sig.safety == hax::Safety::Unsafe,
365            abi: Self::translate_abi(&sig.abi),
366            is_variadic: sig.c_variadic,
367            inputs,
368            output,
369        })
370    }
371
372    pub fn translate_abi(abi: &hax::ExternAbi) -> Abi {
373        match abi {
374            hax::ExternAbi::Rust => Abi::Rust,
375            hax::ExternAbi::C { unwind: false } => Abi::C,
376            _ => Abi::Other(abi.as_str().into()),
377        }
378    }
379
380    /// Translate generic args. Don't call directly; use `translate_xxx_ref` as much as possible.
381    pub fn translate_generic_args(
382        &mut self,
383        span: Span,
384        substs: &[hax::GenericArg],
385        trait_refs: &[hax::TraitProof],
386    ) -> Result<GenericArgs, Error> {
387        use crate::hax::GenericArg::*;
388        trace!("{:?}", substs);
389
390        let mut regions = IndexVec::new();
391        let mut types = IndexVec::new();
392        let mut const_generics = IndexVec::new();
393        for param in substs {
394            match param {
395                Type(param_ty) => {
396                    types.push(self.translate_ty(span, param_ty)?);
397                }
398                Lifetime(region) => {
399                    regions.push(self.translate_region(span, region)?);
400                }
401                Const(c) => {
402                    const_generics.push(self.translate_constant_expr(span, c)?);
403                }
404            }
405        }
406        let trait_refs = self.translate_trait_proofs(span, trait_refs)?;
407
408        Ok(GenericArgs {
409            regions,
410            types,
411            const_generics,
412            trait_refs,
413        })
414    }
415
416    /// Checks whether the given id corresponds to a built-in type.
417    pub(crate) fn recognize_builtin_type(
418        &mut self,
419        item: &hax::ItemRef,
420    ) -> Result<Option<BuiltinTy>, Error> {
421        let def = self.hax_def(item)?;
422        let ty = if def.lang_item == Some(sym::owned_box) && self.t_ctx.options.treat_box_as_builtin
423        {
424            Some(BuiltinTy::Box)
425        } else {
426            None
427        };
428        Ok(ty)
429    }
430
431    /// Translate a Dynamically Sized Type metadata kind.
432    ///
433    /// Returns `None` if the type is generic, or if it is not a DST.
434    pub fn translate_ptr_metadata(
435        &mut self,
436        span: Span,
437        item: &hax::ItemRef,
438    ) -> Result<PtrMetadata, Error> {
439        // prepare the call to the method
440        use rustc_middle::ty;
441        let tcx = self.t_ctx.tcx;
442        let hax_state = &self.hax_state;
443        let ty_env = hax_state.typing_env();
444        let ty = item
445            .def_id
446            .type_of(hax_state)
447            .instantiate(tcx, item.rustc_args(hax_state));
448        let ty = hax::normalize(tcx, ty_env, ty);
449
450        // Get the tail type, which determines the metadata of `ty`.
451        let tail_ty = tcx.struct_tail_raw(
452            ty,
453            &rustc_middle::traits::ObligationCause::dummy(),
454            |ty| hax::normalize(tcx, ty_env, ty),
455            || {},
456        );
457        let hax_ty: hax::Ty = self.t_ctx.catch_sinto(hax_state, span, &tail_ty)?;
458
459        // If we're hiding `Sized`, let's consider everything to be sized.
460        let everything_is_sized = self.t_ctx.options.hide_marker_traits;
461        let ret = match tail_ty.kind() {
462            _ if everything_is_sized || tail_ty.is_sized(tcx, ty_env) => PtrMetadata::None,
463            ty::Str | ty::Slice(..) => PtrMetadata::Length,
464            ty::Dynamic(..) => match hax_ty.kind() {
465                hax::TyKind::Dynamic(dyn_binder, _) => {
466                    let vtable = self.translate_dyn_binder(span, dyn_binder, |ctx, _, _| {
467                        ctx.translate_region_binder(
468                            span,
469                            &dyn_binder.predicates.predicates[0].clause.kind,
470                            |ctx, kind: &hax::ClauseKind| {
471                                let hax::ClauseKind::Trait(trait_predicate) = kind else {
472                                    unreachable!()
473                                };
474                                ctx.translate_vtable_struct_ref(span, &trait_predicate.trait_ref)
475                            },
476                        )
477                    })?;
478                    let vtable = vtable
479                        .skip_binder
480                        .try_substitute(&GenericArgs::empty())
481                        .expect("vtable struct should not depend on self type");
482                    let vtable = self.erase_region_binder(vtable);
483                    PtrMetadata::VTable(vtable)
484                }
485                _ => unreachable!("Unexpected hax type {hax_ty:?} for dynamic type: {ty:?}"),
486            },
487            ty::Param(..) => PtrMetadata::InheritFrom(self.translate_ty(span, &hax_ty)?),
488            ty::Placeholder(..) | ty::Infer(..) | ty::Bound(..) => {
489                panic!(
490                    "We should never encounter a placeholder, infer, or bound type from ptr_metadata translation. Got: {tail_ty:?}"
491                )
492            }
493            _ => PtrMetadata::None,
494        };
495
496        Ok(ret)
497    }
498
499    /// Translate a type layout.
500    ///
501    /// Translates the layout as queried from rustc into
502    /// the more restricted [`Layout`].
503    #[tracing::instrument(skip(self))]
504    pub fn translate_layout(&mut self, def: &hax::FullDef<'tcx>) -> Option<Layout> {
505        let item = def.this();
506        use rustc_abi as r_abi;
507
508        fn translate_variant_layout(
509            variant_layout: &r_abi::VariantLayout<r_abi::FieldIdx>,
510            tagger: Vec<(ByteCount, ScalarValue)>,
511        ) -> Option<VariantLayout> {
512            let field_offsets = variant_layout
513                .field_offsets
514                .iter()
515                .map(|o| o.bytes())
516                .collect();
517            Some(VariantLayout {
518                field_offsets,
519                uninhabited: variant_layout.is_uninhabited(),
520                tagger,
521            })
522        }
523
524        fn translate_layout_data(
525            layout_data: &r_abi::LayoutData<r_abi::FieldIdx, r_abi::VariantIdx>,
526            tagger: Vec<(ByteCount, ScalarValue)>,
527        ) -> Option<VariantLayout> {
528            let field_offsets = match &layout_data.fields {
529                r_abi::FieldsShape::Arbitrary { offsets, .. } => {
530                    offsets.iter().map(|o| o.bytes()).collect()
531                }
532                r_abi::FieldsShape::Union(n) => vec![0; n.get()].into(),
533                r_abi::FieldsShape::Primitive => IndexVec::default(),
534                r_abi::FieldsShape::Array { .. } => panic!("Unexpected layout shape"),
535            };
536            Some(VariantLayout {
537                field_offsets,
538                uninhabited: layout_data.is_uninhabited(),
539                tagger,
540            })
541        }
542
543        fn translate_primitive_int(int_ty: r_abi::Integer, signed: bool) -> IntegerTy {
544            if signed {
545                IntegerTy::Signed(match int_ty {
546                    r_abi::Integer::I8 => IntTy::I8,
547                    r_abi::Integer::I16 => IntTy::I16,
548                    r_abi::Integer::I32 => IntTy::I32,
549                    r_abi::Integer::I64 => IntTy::I64,
550                    r_abi::Integer::I128 => IntTy::I128,
551                })
552            } else {
553                IntegerTy::Unsigned(match int_ty {
554                    r_abi::Integer::I8 => UIntTy::U8,
555                    r_abi::Integer::I16 => UIntTy::U16,
556                    r_abi::Integer::I32 => UIntTy::U32,
557                    r_abi::Integer::I64 => UIntTy::U64,
558                    r_abi::Integer::I128 => UIntTy::U128,
559                })
560            }
561        }
562
563        let tcx = self.t_ctx.tcx;
564        let hax_state = self.hax_state_with_id();
565        assert_eq!(hax_state.owner(), item.def_id);
566        let ty_env = hax_state.typing_env();
567        let ty = item
568            .def_id
569            .type_of(hax_state)
570            .instantiate(tcx, item.rustc_args(hax_state));
571        let ty = hax::normalize(tcx, ty_env, ty);
572        let pseudo_input = ty_env.as_query_input(ty);
573        let ptr_size = self.translated.the_target_information().target_pointer_size;
574
575        // If layout computation returns an error, we return `None`.
576        let layout = tcx.layout_of(pseudo_input).ok()?.layout;
577        let (size, align) = if layout.is_sized() {
578            (
579                Some(layout.size().bytes()),
580                Some(layout.align().abi.bytes()),
581            )
582        } else {
583            (None, None)
584        };
585
586        // Build the discriminator tree and variant layouts.
587        let (discriminator, variant_layouts) = match layout.variants() {
588            r_abi::Variants::Multiple {
589                tag,
590                tag_encoding,
591                tag_field,
592                variants,
593                ..
594            } => {
595                // The tag_field is the index into the `offsets` vector.
596                let r_abi::FieldsShape::Arbitrary { offsets, .. } = layout.fields() else {
597                    unreachable!()
598                };
599                let tag_offset = offsets
600                    .get(*tag_field)
601                    .map(|s| r_abi::Size::bytes(*s))
602                    .expect("No tag field offset for enum?");
603
604                let tag_ty = match tag.primitive() {
605                    r_abi::Primitive::Int(int_ty, signed) => {
606                        translate_primitive_int(int_ty, signed)
607                    }
608                    r_abi::Primitive::Pointer(_) => IntegerTy::Signed(IntTy::Isize),
609                    r_abi::Primitive::Float(_) => unreachable!(),
610                };
611                let tag_size = r_abi::Size::from_bytes(tag_ty.target_size(ptr_size));
612                let tag_for_variant = |id: rustc_abi::VariantIdx| {
613                    tcx.tag_for_variant(ty_env.as_query_input((ty, id)))
614                        .map(|s| match tag_ty {
615                            IntegerTy::Signed(int_ty) => {
616                                ScalarValue::from_int(ptr_size, int_ty, s.to_int(tag_size)).unwrap()
617                            }
618                            IntegerTy::Unsigned(uint_ty) => {
619                                ScalarValue::from_uint(ptr_size, uint_ty, s.to_uint(tag_size))
620                                    .unwrap()
621                            }
622                        })
623                };
624
625                // Compute per-variant tag values and build tagger + discriminator children.
626                let mut variant_layouts: IndexVec<VariantId, Option<VariantLayout>> =
627                    IndexVec::new();
628                let mut children = Vec::new();
629
630                for (id, variant_layout) in variants.iter_enumerated() {
631                    let variant_id = self.translate_variant_id(id);
632                    let tagger = if variant_layout.is_uninhabited() {
633                        vec![]
634                    } else if let Some(val) = tag_for_variant(id) {
635                        children.push((val..=val, Discriminator::Known(variant_id)));
636                        vec![(tag_offset, val)]
637                    } else {
638                        // Niched variant
639                        vec![]
640                    };
641                    variant_layouts.push(translate_variant_layout(variant_layout, tagger));
642                }
643
644                let fallback = match tag_encoding {
645                    r_abi::TagEncoding::Direct => Discriminator::Invalid,
646                    r_abi::TagEncoding::Niche {
647                        untagged_variant,
648                        niche_variants,
649                        ..
650                    } => {
651                        if niche_variants.contains(untagged_variant)
652                            && let Some(start) = tag_for_variant(niche_variants.start)
653                            && let Some(end) = tag_for_variant(niche_variants.last)
654                        {
655                            // Add an inner discriminator; the outer one filters the whole range of
656                            // values considered to be discriminants, the inner one selects known
657                            // variants from within that range. This is to detect the UB that
658                            // happens if we encounter a discriminant that would have been the
659                            // niched variant.
660                            let discriminator = Discriminator::Branch {
661                                offset: tag_offset,
662                                int_ty: tag_ty,
663                                fallback: Box::new(Discriminator::Invalid),
664                                children,
665                            };
666                            children = vec![(start..=end, discriminator)];
667                        }
668                        Discriminator::Known(self.translate_variant_id(*untagged_variant))
669                    }
670                };
671
672                let discriminator = Discriminator::Branch {
673                    offset: tag_offset,
674                    int_ty: tag_ty,
675                    fallback: Box::new(fallback),
676                    children,
677                };
678
679                (Some(discriminator), variant_layouts)
680            }
681            r_abi::Variants::Single { index } => {
682                let variant_id = self.translate_variant_id(*index);
683                let variant_layouts = match layout.fields() {
684                    r_abi::FieldsShape::Arbitrary { .. } => {
685                        let n_variants = if let Some(range) = ty.variant_range(self.t_ctx.tcx) {
686                            range.end.index()
687                        } else {
688                            1
689                        };
690                        let mut variant_layouts: IndexVec<VariantId, Option<VariantLayout>> =
691                            (0..n_variants).map(|_| None).collect();
692                        variant_layouts[variant_id] = translate_layout_data(&layout, vec![]);
693                        variant_layouts
694                    }
695                    r_abi::FieldsShape::Union(_) => {
696                        vec![translate_layout_data(&layout, vec![])].into()
697                    }
698                    r_abi::FieldsShape::Primitive | r_abi::FieldsShape::Array { .. } => {
699                        vec![].into()
700                    }
701                };
702                (Some(Discriminator::trivial(variant_id)), variant_layouts)
703            }
704            r_abi::Variants::Empty => (None, IndexVec::new()),
705        };
706
707        let repr = match &def.kind {
708            hax::FullDefKind::Adt { repr: hax_repr, .. } => self.translate_repr_options(hax_repr),
709            _ => ReprOptions::default(),
710        };
711
712        Some(Layout {
713            size,
714            align,
715            discriminator,
716            uninhabited: layout.is_uninhabited(),
717            variant_layouts,
718            repr,
719        })
720    }
721
722    /// Generate a naive layout for this type.
723    pub fn generate_naive_layout(&self, span: Span, ty: &TypeDeclKind) -> Result<Layout, Error> {
724        match ty {
725            TypeDeclKind::Struct(fields) => {
726                let mut size = 0;
727                let mut align = 0;
728                let ptr_size = self.translated.the_target_information().target_pointer_size;
729                let field_offsets = fields.map_ref(|field| {
730                    let offset = size;
731                    let size_of_ty = match field.ty.kind() {
732                        TyKind::Literal(literal_ty) => literal_ty.target_size(ptr_size) as u64,
733                        // This is a lie, the pointers could be fat...
734                        TyKind::Ref(..) | TyKind::RawPtr(..) | TyKind::FnPtr(..) => ptr_size,
735                        _ => panic!("Unsupported type for `generate_naive_layout`: {ty:?}"),
736                    };
737                    size += size_of_ty;
738                    // For these types, align == size is good enough.
739                    align = std::cmp::max(align, size);
740                    offset
741                });
742
743                Ok(Layout {
744                    size: Some(size),
745                    align: Some(align),
746                    discriminator: None,
747                    uninhabited: false,
748                    variant_layouts: IndexVec::from([Some(VariantLayout {
749                        field_offsets,
750                        tagger: vec![],
751                        uninhabited: false,
752                    })]),
753                    repr: ReprOptions::default(),
754                })
755            }
756            _ => raise_error!(
757                self,
758                span,
759                "`generate_naive_layout` only supports structs at the moment"
760            ),
761        }
762    }
763
764    /// Translate the body of a type declaration.
765    ///
766    /// Note that the type may be external, in which case we translate the body
767    /// only if it is public (i.e., it is a public enumeration, or it is a
768    /// struct with only public fields).
769    pub(crate) fn translate_adt_def(
770        &mut self,
771        trans_id: TypeDeclId,
772        def_span: Span,
773        item_meta: &ItemMeta,
774        def: &hax::FullDef<'tcx>,
775    ) -> Result<TypeDeclKind, Error> {
776        use crate::hax::AdtKind;
777        let hax::FullDefKind::Adt {
778            adt_kind, variants, ..
779        } = def.kind()
780        else {
781            unreachable!()
782        };
783
784        if item_meta.opacity.is_opaque() {
785            return Ok(TypeDeclKind::Opaque);
786        }
787
788        trace!("{}", trans_id);
789
790        // In case the type is external, check if we should consider the type as
791        // transparent (i.e., extract its body). If it is an enumeration, then yes
792        // (because the variants of public enumerations are public, together with their
793        // fields). If it is a structure, we check if all the fields are public.
794        let contents_are_public = match adt_kind {
795            AdtKind::Enum => true,
796            AdtKind::Struct | AdtKind::Union => {
797                // Check the unique variant
798                error_assert!(self, def_span, variants.len() == 1);
799                variants[hax::VariantIdx::from(0usize)]
800                    .fields
801                    .iter()
802                    .all(|f| matches!(f.vis, Visibility::Public))
803            }
804            // The rest are fake adt kinds that won't reach here.
805            _ => unreachable!(),
806        };
807
808        if item_meta
809            .opacity
810            .with_content_visibility(contents_are_public)
811            .is_opaque()
812        {
813            return Ok(TypeDeclKind::Opaque);
814        }
815
816        // The type is transparent: explore the variants
817        let mut translated_variants: IndexVec<VariantId, Variant> = Default::default();
818        for (i, var_def) in variants.iter().enumerate() {
819            trace!("variant {i}: {var_def:?}");
820
821            let mut fields: IndexVec<FieldId, Field> = Default::default();
822            /* This is for sanity: check that either all the fields have names, or
823             * none of them has */
824            let mut have_names: Option<bool> = None;
825            for (j, field_def) in var_def.fields.iter().enumerate() {
826                trace!("variant {i}: field {j}: {field_def:?}");
827                let field_span = self.t_ctx.translate_span(&field_def.span);
828                // Translate the field type
829                let ty = self.translate_ty(field_span, &field_def.ty)?;
830                let field_full_def =
831                    self.hax_def(&def.this().with_def_id(self.hax_state(), &field_def.did))?;
832                let field_attrs = self.t_ctx.translate_attr_info(&field_full_def);
833
834                // Retrieve the field name.
835                let field_name = field_def.name.map(|s| s.to_string());
836                // Sanity check
837                match &have_names {
838                    None => {
839                        have_names = match &field_name {
840                            None => Some(false),
841                            Some(_) => Some(true),
842                        }
843                    }
844                    Some(b) => {
845                        error_assert!(self, field_span, *b == field_name.is_some());
846                    }
847                };
848
849                // Store the field
850                let field = Field {
851                    span: field_span,
852                    attr_info: field_attrs,
853                    name: field_name,
854                    ty,
855                };
856                fields.push(field);
857            }
858
859            let discriminant = self.translate_discriminant(def_span, &var_def.discr_val)?;
860            let variant_span = self.t_ctx.translate_span(&var_def.span);
861            let variant_name = var_def.name.to_string();
862            let variant_full_def =
863                self.hax_def(&def.this().with_def_id(self.hax_state(), &var_def.def_id))?;
864
865            let mut variant_attrs = self.t_ctx.translate_attr_info(&variant_full_def);
866            // Propagate a `#[charon::variants_prefix(..)]` or `#[charon::variants_suffix(..)]` attribute to the variants.
867            if variant_attrs.rename.is_none() {
868                let prefix = item_meta
869                    .attr_info
870                    .attributes
871                    .iter()
872                    .filter_map(|a| a.as_variants_prefix())
873                    .next()
874                    .map(|attr| attr.as_str());
875                let suffix = item_meta
876                    .attr_info
877                    .attributes
878                    .iter()
879                    .filter_map(|a| a.as_variants_suffix())
880                    .next()
881                    .map(|attr| attr.as_str());
882                if prefix.is_some() || suffix.is_some() {
883                    let prefix = prefix.unwrap_or_default();
884                    let suffix = suffix.unwrap_or_default();
885                    variant_attrs.rename = Some(format!("{prefix}{variant_name}{suffix}"));
886                }
887            }
888
889            translated_variants.push_with(|id| Variant {
890                id,
891                span: variant_span,
892                attr_info: variant_attrs,
893                name: variant_name,
894                fields,
895                discriminant,
896            });
897        }
898
899        // Register the type
900        let type_def_kind: TypeDeclKind = match adt_kind {
901            AdtKind::Struct => TypeDeclKind::Struct(translated_variants[0].fields.clone()),
902            AdtKind::Enum => TypeDeclKind::Enum(translated_variants),
903            AdtKind::Union => TypeDeclKind::Union(translated_variants[0].fields.clone()),
904            // The rest are fake adt kinds that won't reach here.
905            _ => unreachable!(),
906        };
907
908        Ok(type_def_kind)
909    }
910
911    fn translate_discriminant(
912        &mut self,
913        def_span: Span,
914        discr: &hax::DiscriminantValue,
915    ) -> Result<Literal, Error> {
916        let ty = self.translate_ty(def_span, &discr.ty)?;
917        let lit_ty = ty.kind().as_literal().unwrap();
918        match Literal::from_bits(lit_ty, discr.val) {
919            Some(lit) => Ok(lit),
920            None => raise_error!(self, def_span, "unexpected discriminant type: {ty:?}",),
921        }
922    }
923
924    pub fn translate_repr_options(&mut self, hax_repr_options: &hax::ReprOptions) -> ReprOptions {
925        let repr_algo = if hax_repr_options.flags.is_c {
926            ReprAlgorithm::C
927        } else {
928            ReprAlgorithm::Rust
929        };
930
931        let align_mod = if let Some(align) = &hax_repr_options.align {
932            Some(AlignmentModifier::Align(align.bytes))
933        } else if let Some(pack) = &hax_repr_options.pack {
934            Some(AlignmentModifier::Pack(pack.bytes))
935        } else {
936            None
937        };
938
939        ReprOptions {
940            transparent: hax_repr_options.flags.is_transparent,
941            explicit_discr_type: hax_repr_options.int_specified,
942            repr_algo,
943            align_modif: align_mod,
944        }
945    }
946}
charon_driver/translate/translate_types.rs

charon_driver/translate/
translate_types.rs
