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

charon_driver/translate/
translate_types.rs
