charon_driver/translate/
translate_types.rs

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

charon_driver/translate/
translate_types.rs
