charon_lib/transform/simplify_output/
builtins_to_function_calls.rs

1//! Desugar built-in operations and array/slice indexing to standard library function calls.
2
3use std::collections::{HashMap, HashSet};
4
5use crate::llbc_ast::*;
6use crate::name_matcher::NamePattern;
7use crate::transform::ctx::{BodyTransformCtx, LlbcStatementTransformCtx};
8use crate::transform::{CowBox, TransformCtx};
9use derive_generic_visitor::*;
10use itertools::Itertools;
11
12use crate::transform::ctx::LlbcPass;
13
14fn mk_fn_ptr(ctx: &TransformCtx, id: ItemId, mut generics: GenericArgs) -> FnPtr {
15    if ctx.options.add_destruct_bounds
16        && let Some(item) = ctx.translated.get_item(id)
17    {
18        // Charon adds `Destruct` as the last trait clause of every generic item.
19        let trait_decl_ref = item
20            .generic_params()
21            .trait_clauses
22            .last()
23            .unwrap()
24            .trait_
25            .clone()
26            .substitute(&generics);
27        let kind = TraitRefKind::BuiltinOrAuto {
28            builtin_data: BuiltinImplData::UntrackedDestruct,
29            parent_trait_refs: Default::default(),
30            types: Default::default(),
31            vtable: None,
32        };
33        generics
34            .trait_refs
35            .push(TraitRef::new(kind, trait_decl_ref));
36    }
37    let fun_id = *id.as_fun().unwrap();
38    FnPtr::new(FnPtrKind::Fun(fun_id), generics)
39}
40
41/// Instantiate the trait impl that provides the given method.
42fn method_impl_trait_ref(
43    ctx: &TransformCtx,
44    id: ItemId,
45    fun_generics: &GenericArgs,
46) -> Option<TraitRef> {
47    let fun_id = *id.as_fun()?;
48    let fun = ctx.translated.fun_decls.get(fun_id)?;
49    let FunSource::TraitImpl { impl_ref, .. } = &fun.src else {
50        return None;
51    };
52    let impl_ref = impl_ref.clone().substitute(fun_generics);
53    let trait_impl = ctx.translated.trait_impls.get(impl_ref.id)?;
54    let trait_decl_ref =
55        RegionBinder::empty(trait_impl.impl_trait.clone().substitute(&impl_ref.generics));
56    Some(TraitRef::new(
57        TraitRefKind::TraitImpl(impl_ref),
58        trait_decl_ref,
59    ))
60}
61
62fn index_method_types(
63    params: &GenericParams,
64    elem_ty: &Ty,
65    index_ty: &Ty,
66    output_ty: &Ty,
67) -> Option<IndexVec<TypeVarId, Ty>> {
68    let mut types: IndexVec<TypeVarId, Ty> =
69        [elem_ty.clone(), index_ty.clone()].into_iter().collect();
70    match params.types.len() {
71        // With `--lift-associated-types`, `Index::Output` is an explicit type parameter.
72        3 => {
73            types.push(output_ty.clone());
74        }
75        2 => {}
76        _ => return None,
77    }
78    Some(types)
79}
80
81fn transform_operation(std_items: &Transform, ctx: &TransformCtx, statement: &mut Statement) {
82    match &statement.kind {
83        // Transform the ArrayToSlice unop.
84        StatementKind::Assign(
85            place,
86            Rvalue::UnaryOp(
87                UnOp::Cast(CastKind::Unsize(src_ty, tgt_ty, UnsizingMetadata::Length(_))),
88                operand,
89            ),
90        ) => {
91            if let (TyKind::Ref(_, src_ty, src_kind), TyKind::Ref(_, tgt_ty, tgt_kind)) =
92                (src_ty.kind(), tgt_ty.kind())
93                && let TyKind::Array(elem_ty, len, elem_ty_is_sized) = src_ty.kind()
94                && let TyKind::Slice(..) = tgt_ty.kind()
95            {
96                // In MIR terminology, we go from &[T; l] to &[T] which means we
97                // effectively "unsize" the type, as `l` no longer appears in the
98                // destination type. At runtime, the converse happens: the length
99                // materializes into the fat pointer.
100                assert!(src_kind == tgt_kind);
101                // We could avoid the clone operations below if we take the content of
102                // the statement. In practice, this shouldn't have much impact.
103                let item = match src_kind {
104                    RefKind::Shared => StdItem::ArrayAsSlice,
105                    RefKind::Mut => StdItem::ArrayAsMutSlice,
106                };
107                let Some(&fun_id) = std_items.item_map.get(&item) else {
108                    return;
109                };
110                let generics = GenericArgs::new(
111                    [Region::Erased].into(),
112                    [elem_ty.clone()].into(),
113                    [len.clone()].into(),
114                    elem_ty_is_sized.iter().cloned().collect(),
115                );
116                statement.kind = StatementKind::Call {
117                    call: Call {
118                        func: FnOperand::Regular(mk_fn_ptr(ctx, fun_id, generics)),
119                        args: vec![operand.clone()],
120                        dest: place.clone(),
121                    },
122                    on_unwind: Block::new_unreachable(statement.span),
123                };
124            }
125        }
126        // Transform the array aggregates to function calls.
127        StatementKind::Assign(place, Rvalue::Repeat(operand, ty, len, ty_is_copy)) => {
128            let Some(ty_is_copy) = ty_is_copy else {
129                return;
130            };
131            // We could avoid the clone operations below if we take the content of
132            // the statement. In practice, this shouldn't have much impact.
133            let Some(&fun_id) = std_items.item_map.get(&StdItem::ArrayRepeat) else {
134                return;
135            };
136            let TyKind::Array(_, _, ty_is_sized) = place.ty().kind() else {
137                return;
138            };
139            // `Copy`'s explicit `Clone` supertrait follows its optional implicit marker clause.
140            // `array::repeat` has the corresponding `Clone` bound at the same position.
141            let clone_clause_id = TraitClauseId::new(usize::from(ty_is_sized.is_some()));
142            let Some(ty_is_clone) = ty_is_copy
143                .clone()
144                .project_parent_clause(&ctx.translated, clone_clause_id)
145            else {
146                return;
147            };
148            let generics = GenericArgs::new(
149                [].into(),
150                [ty.clone()].into(),
151                [len.clone()].into(),
152                ty_is_sized.iter().cloned().chain([ty_is_clone]).collect(),
153            );
154            statement.kind = StatementKind::Call {
155                call: Call {
156                    func: FnOperand::Regular(mk_fn_ptr(ctx, fun_id, generics)),
157                    args: vec![operand.clone()],
158                    dest: place.clone(),
159                },
160                on_unwind: Block::new_unreachable(statement.span),
161            };
162        }
163        _ => {}
164    }
165}
166
167/// We replace some place constructors with function calls. To do that, we explore all the places
168/// in a body and deconstruct a given place access into intermediate assignments.
169///
170/// We accumulate the new assignments as statements in the visitor, and at the end we insert these
171/// statements before the one that was just explored.
172#[derive(Visitor)]
173struct IndexVisitor<'a, 'b> {
174    ctx: &'b mut LlbcStatementTransformCtx<'a>,
175    std_items: &'b Transform,
176    // When we visit a place, we need to know if it is being accessed mutably or not. Whenever we
177    // visit something that contains a place we push the relevant mutability on this stack.
178    // Unfortunately this requires us to be very careful to catch all the cases where we see
179    // places.
180    place_mutability_stack: Vec<bool>,
181}
182
183impl<'a, 'b> IndexVisitor<'a, 'b> {
184    /// transform `place: subplace[i]` into indexing function calls for `subplace` and `i`
185    fn transform_place(&mut self, mut_access: bool, place: &mut Place) {
186        use ProjectionElem::*;
187        // This function is naturally called recusively, so `subplace` cannot be another `Index` or `Subslice`.
188        // Hence, `subplace`, if still projecting, must be either a `Deref` or a `Field`.
189        let Some((subplace, pe @ (Index { .. } | Subslice { .. }))) = place.as_projection() else {
190            return;
191        };
192
193        let (ty, len, ty_is_sized) = match subplace.ty.kind() {
194            TyKind::Array(ty, len, ty_is_sized) => (ty.clone(), Some(len.clone()), ty_is_sized),
195            TyKind::Slice(ty, ty_is_sized) => (ty.clone(), None, ty_is_sized),
196            _ => unreachable!("Indexing can only be done on arrays or slices"),
197        };
198
199        let mutability = RefKind::mutable(mut_access);
200        let item = match (pe.is_subslice(), mutability) {
201            (false, RefKind::Shared) => StdItem::SliceIndex,
202            (false, RefKind::Mut) => StdItem::SliceIndexMut,
203            (true, RefKind::Shared) => StdItem::RangeIndex,
204            (true, RefKind::Mut) => StdItem::RangeIndexMut,
205        };
206        let Some(&index_fun_id) = self.std_items.item_map.get(&item) else {
207            return;
208        };
209        let Some(index_fun) = index_fun_id
210            .as_fun()
211            .and_then(|id| self.ctx.ctx.translated.fun_decls.get(*id))
212        else {
213            return;
214        };
215        let index_generics = GenericArgs::new(
216            [Region::Erased].into(),
217            [ty.clone()].into(),
218            [].into(),
219            ty_is_sized.iter().cloned().collect(),
220        );
221        let index_fn_ptr = mk_fn_ptr(self.ctx.ctx, index_fun_id, index_generics);
222        let index_ty = index_fun.signature.inputs[0]
223            .clone()
224            .substitute(&index_fn_ptr.generics);
225
226        let output_inner_ty = if matches!(pe, Index { .. }) {
227            ty.clone()
228        } else {
229            TyKind::Slice(ty.clone(), ty_is_sized.clone()).into_ty()
230        };
231        let output_ty = {
232            TyKind::Ref(
233                Region::Erased,
234                output_inner_ty.clone(),
235                RefKind::mutable(mut_access),
236            )
237            .into_ty()
238        };
239
240        // Push the statements:
241        // `storage_live(tmp0)`
242        // `tmp0 = &{mut}p`
243        let input_var =
244            self.ctx
245                .borrow_to_new_var(subplace.clone(), BorrowKind::mutable(mut_access), None);
246
247        // Construct the arguments to pass to the indexing function.
248        let (last_arg, from_end) = match &pe {
249            Index {
250                offset: x,
251                from_end,
252                ..
253            }
254            | Subslice {
255                to: x, from_end, ..
256            } => (x.as_ref().clone(), *from_end),
257            _ => unreachable!(),
258        };
259        let to_idx = self
260            .ctx
261            .compute_subslice_end_idx(subplace, last_arg, from_end);
262        let index = match &pe {
263            Index { .. } => to_idx,
264            Subslice { from, .. } => {
265                let Some(range_ref) = index_ty.as_adt().cloned() else {
266                    return;
267                };
268                let range_ty = TyKind::Adt(range_ref.clone()).into_ty();
269                let range_var = self.ctx.fresh_var(None, range_ty);
270                self.ctx.insert_assn_stmt(
271                    range_var.clone(),
272                    Rvalue::Aggregate(
273                        AggregateKind::Adt(range_ref, None, None),
274                        vec![from.as_ref().clone(), to_idx],
275                    ),
276                );
277                Operand::Move(range_var)
278            }
279            _ => unreachable!(),
280        };
281
282        let (index_fn_ptr, args) = if let Some(len) = len {
283            let (array_item, slice_item) = match mutability {
284                RefKind::Shared => (StdItem::ArrayIndex, StdItem::SliceIndexImpl),
285                RefKind::Mut => (StdItem::ArrayIndexMut, StdItem::SliceIndexMutImpl),
286            };
287            let Some(&array_fun_id) = self.std_items.item_map.get(&array_item) else {
288                return;
289            };
290            let Some(array_fun) = array_fun_id
291                .as_fun()
292                .and_then(|id| self.ctx.ctx.translated.fun_decls.get(*id))
293            else {
294                return;
295            };
296            let Some(&slice_fun_id) = self.std_items.item_map.get(&slice_item) else {
297                return;
298            };
299            let Some(slice_fun) = slice_fun_id
300                .as_fun()
301                .and_then(|id| self.ctx.ctx.translated.fun_decls.get(*id))
302            else {
303                return;
304            };
305
306            let Some(slice_types) =
307                index_method_types(&slice_fun.generics, &ty, &index_ty, &output_inner_ty)
308            else {
309                return;
310            };
311            let mut slice_generics =
312                GenericArgs::new([Region::Erased].into(), slice_types, [].into(), [].into());
313            let Some(slice_index_trait_ref) =
314                method_impl_trait_ref(self.ctx.ctx, index_fun_id, &index_fn_ptr.generics)
315            else {
316                return;
317            };
318            let index_ty_is_sized = if ty_is_sized.is_some() {
319                let Some(clause) = slice_fun.generics.trait_clauses.get(TraitClauseId::new(1))
320                else {
321                    return;
322                };
323                let trait_decl_ref = clause.trait_.clone().substitute_explicits(&slice_generics);
324                let Some(meta_sized) = slice_index_trait_ref
325                    .clone()
326                    .project_parent_clause(&self.ctx.ctx.translated, TraitClauseId::ZERO)
327                else {
328                    return;
329                };
330                Some(TraitRef::new(
331                    TraitRefKind::BuiltinOrAuto {
332                        builtin_data: BuiltinImplData::Sized,
333                        parent_trait_refs: [meta_sized].into_iter().collect(),
334                        types: Default::default(),
335                        vtable: None,
336                    },
337                    trait_decl_ref,
338                ))
339            } else {
340                None
341            };
342            slice_generics.trait_refs = ty_is_sized
343                .iter()
344                .cloned()
345                .chain(index_ty_is_sized.iter().cloned())
346                .chain([slice_index_trait_ref])
347                .collect();
348            let slice_fn_ptr = mk_fn_ptr(self.ctx.ctx, slice_fun_id, slice_generics);
349            let Some(slice_trait_ref) =
350                method_impl_trait_ref(self.ctx.ctx, slice_fun_id, &slice_fn_ptr.generics)
351            else {
352                return;
353            };
354
355            let Some(array_types) =
356                index_method_types(&array_fun.generics, &ty, &index_ty, &output_inner_ty)
357            else {
358                return;
359            };
360            let array_generics = GenericArgs::new(
361                [Region::Erased].into(),
362                array_types,
363                [len].into(),
364                ty_is_sized
365                    .iter()
366                    .cloned()
367                    .chain(index_ty_is_sized)
368                    .chain([slice_trait_ref])
369                    .collect(),
370            );
371            (
372                mk_fn_ptr(self.ctx.ctx, array_fun_id, array_generics),
373                vec![Operand::Move(input_var), index],
374            )
375        } else {
376            (index_fn_ptr, vec![index, Operand::Move(input_var)])
377        };
378
379        // Call the indexing function:
380        // `storage_live(tmp1)`
381        // `tmp1 = {Array,Slice}{Mut,Shared}{Index,SubSlice}(move tmp0, <other args>)`
382        let output_var = {
383            let output_var = self.ctx.fresh_var(None, output_ty);
384            let index_call = Call {
385                func: FnOperand::Regular(index_fn_ptr),
386                args,
387                dest: output_var.clone(),
388            };
389            let kind = StatementKind::Call {
390                call: index_call,
391                on_unwind: Block::new_unreachable(self.ctx.span),
392            };
393            self.ctx
394                .statements
395                .push(Statement::new(self.ctx.span, kind));
396            output_var
397        };
398
399        // Update the place.
400        *place = output_var.project(ProjectionElem::Deref, output_inner_ty);
401    }
402
403    /// Calls `self.visit_inner()` with `mutability` pushed on the stack.
404    fn visit_inner_with_mutability<T>(
405        &mut self,
406        x: &mut T,
407        mutability: bool,
408    ) -> ControlFlow<Infallible>
409    where
410        T: for<'s> DriveMut<'s, BodyVisitableWrapper<Self>> + BodyVisitable,
411    {
412        self.place_mutability_stack.push(mutability);
413        self.visit_inner(x)?;
414        self.place_mutability_stack.pop();
415        Continue(())
416    }
417}
418
419/// The visitor methods.
420impl VisitBodyMut for IndexVisitor<'_, '_> {
421    /// We explore places from the inside-out --- recursion naturally happens here.
422    fn exit_place(&mut self, place: &mut Place) {
423        // We have intercepted every traversal that would reach a place and pushed the correct
424        // mutability on the stack.
425        let mut_access = *self.place_mutability_stack.last().unwrap();
426        self.transform_place(mut_access, place);
427    }
428
429    fn visit_operand(&mut self, x: &mut Operand) -> ControlFlow<Infallible> {
430        match x {
431            Operand::Move(_) => self.visit_inner_with_mutability(x, true),
432            Operand::Copy(_) => self.visit_inner_with_mutability(x, false),
433            Operand::Const(..) => self.visit_inner(x),
434        }
435    }
436
437    fn visit_call(&mut self, x: &mut Call) -> ControlFlow<Infallible> {
438        self.visit_inner_with_mutability(x, true)
439    }
440
441    fn visit_fn_operand(&mut self, x: &mut FnOperand) -> ControlFlow<Infallible> {
442        match x {
443            FnOperand::Regular(_) => self.visit_inner(x),
444            FnOperand::Dynamic(_) => self.visit_inner_with_mutability(x, true),
445        }
446    }
447
448    fn visit_rvalue(&mut self, x: &mut Rvalue) -> ControlFlow<Infallible> {
449        use Rvalue::*;
450        match x {
451            // `UniqueImmutable` de facto gives mutable access and only shows up if there is nested
452            // mutable access.
453            RawPtr {
454                kind: RefKind::Mut, ..
455            }
456            | Ref {
457                kind: BorrowKind::Mut | BorrowKind::TwoPhaseMut | BorrowKind::UniqueImmutable,
458                ..
459            } => self.visit_inner_with_mutability(x, true),
460            RawPtr {
461                kind: RefKind::Shared,
462                ..
463            }
464            | Ref {
465                kind: BorrowKind::Shared | BorrowKind::Shallow,
466                ..
467            }
468            | Discriminant(..)
469            | Len(..) => self.visit_inner_with_mutability(x, false),
470
471            Use(..) | NullaryOp(..) | UnaryOp(..) | BinaryOp(..) | Aggregate(..) | Repeat(..) => {
472                self.visit_inner(x)
473            }
474        }
475    }
476
477    fn visit_llbc_block(&mut self, _: &mut llbc_ast::Block) -> ControlFlow<Infallible> {
478        ControlFlow::Continue(())
479    }
480}
481
482/// We do the following.
483///
484/// If `p` is a projection (for instance: `var`, `*var`, `var.f`, etc.), we
485/// detect:
486/// - whether it operates on a slice or an array (we keep track of the types)
487/// - whether the access might mutate the value or not (it is
488///   the case if it is in a `move`, `&mut` or at the lhs of an assignment),
489///   and do the following transformations
490///
491/// ```text
492///   // If array and mutable access:
493///   ... p[i] ...
494///      ~~>
495///   tmp0 = &mut p
496///   tmp1 = <[_; _] as IndexMut<_>>::index_mut(move tmp0, i)
497///   ... *tmp1 ...
498///
499///   // If array and non-mutable access:
500///   ... p[i] ...
501///      ~~>
502///   tmp0 := & p
503///   tmp1 := <[_; _] as Index<_>>::index(move tmp0, i)
504///   ... *tmp1 ...
505///
506///   // Omitting the slice cases, which are similar
507/// ```
508///
509/// For instance, it leads to the following transformations:
510/// ```text
511///   // x : [u32; N]
512///   y : u32 = copy x[i]
513///      ~~>
514///   tmp0 : & [u32; N] := &x
515///   tmp1 : &u32 = <[_; _] as Index<_>>::index(move tmp0, i)
516///   y : u32 = copy (*tmp1)
517///
518///   // x : &[T; N]
519///   y : &T = & (*x)[i]
520///      ~~>
521///   tmp0 : & [T; N] := & (*x)
522///   tmp1 : &T = <[_; _] as Index<_>>::index(move tmp0, i)
523///   y : &T = & (*tmp1)
524///
525///   // x : [u32; N]
526///   y = &mut x[i]
527///      ~~>
528///   tmp0 : &mut [u32; N] := &mut x
529///   tmp1 : &mut u32 := <[_; _] as IndexMut<_>>::index_mut(move tmp0, i)
530///   y = &mut (*tmp)
531///
532///   // When using an index on the lhs:
533///   // y : [T; N]
534///   y[i] = x
535///      ~~>
536///   tmp0 : &mut [T; N] := &mut y;
537///   tmp1 : &mut T = <[_; _] as IndexMut<_>>::index_mut(move tmp0, i)
538///   *tmp1 = x
539/// ```
540#[derive(Clone, Copy, PartialEq, Eq, Hash)]
541enum StdItem {
542    ArrayAsSlice,
543    ArrayAsMutSlice,
544    ArrayRepeat,
545    ArrayIndex,
546    ArrayIndexMut,
547    SliceIndexImpl,
548    SliceIndexMutImpl,
549    SliceIndex,
550    SliceIndexMut,
551    RangeIndex,
552    RangeIndexMut,
553}
554
555pub struct Transform {
556    item_map: HashMap<StdItem, ItemId>,
557    item_set: HashSet<ItemId>,
558}
559
560impl Transform {
561    pub fn new(ctx: &TransformCtx) -> CowBox<dyn LlbcPass> {
562        use StdItem::*;
563
564        let mut matches: [(StdItem, NamePattern, Vec<ItemId>); _] = [
565            (ArrayAsSlice, "core::array::_::as_slice"),
566            (ArrayAsMutSlice, "core::array::_::as_mut_slice"),
567            (ArrayRepeat, "core::array::repeat"),
568            (
569                SliceIndex,
570                "core::slice::index::{impl core::slice::index::SliceIndex<_> for usize}::index",
571            ),
572            (
573                SliceIndexMut,
574                "core::slice::index::{impl core::slice::index::SliceIndex<_> for usize}::index_mut",
575            ),
576            (
577                RangeIndex,
578                "core::slice::index::{impl core::slice::index::SliceIndex<_> for core::ops::range::Range<usize>}::index",
579            ),
580            (
581                RangeIndexMut,
582                "core::slice::index::{impl core::slice::index::SliceIndex<_> for core::ops::range::Range<usize>}::index_mut",
583            ),
584        ]
585        .map(|(item, path)| (item, NamePattern::parse(path).unwrap(), Vec::new()));
586
587        // Resolve the items
588        for (id, name) in &ctx.translated.item_names {
589            for (_, pattern, found) in &mut matches {
590                if pattern.matches(&ctx.translated, name) {
591                    found.push(*id);
592                }
593            }
594        }
595
596        let mut index_impl_methods: HashMap<StdItem, Vec<ItemId>> = HashMap::new();
597        for fun in &ctx.translated.fun_decls {
598            let FunSource::TraitImpl { trait_ref, .. } = &fun.src else {
599                continue;
600            };
601            let Some(trait_decl) = ctx.translated.trait_decls.get(trait_ref.id) else {
602                continue;
603            };
604            let Some(self_ty) = trait_ref.self_ty(&ctx.translated) else {
605                continue;
606            };
607            let item = match (&trait_decl.item_meta.lang_item, self_ty.kind()) {
608                (Some(crate::ast::from_rustc::LangItem::Index), TyKind::Array(..)) => ArrayIndex,
609                (Some(crate::ast::from_rustc::LangItem::IndexMut), TyKind::Array(..)) => {
610                    ArrayIndexMut
611                }
612                (Some(crate::ast::from_rustc::LangItem::Index), TyKind::Slice(..)) => {
613                    SliceIndexImpl
614                }
615                (Some(crate::ast::from_rustc::LangItem::IndexMut), TyKind::Slice(..)) => {
616                    SliceIndexMutImpl
617                }
618                _ => continue,
619            };
620            index_impl_methods
621                .entry(item)
622                .or_default()
623                .push(ItemId::Fun(fun.def_id));
624        }
625        let item_map = matches
626            .into_iter()
627            .map(|(item, _, found)| (item, found))
628            .chain(index_impl_methods)
629            .filter_map(|(item, found)| found.into_iter().exactly_one().ok().map(|id| (item, id)))
630            .collect::<HashMap<_, _>>();
631        let item_set = item_map.values().copied().collect();
632        CowBox::Owned(Box::new(Self { item_map, item_set }))
633    }
634}
635
636impl LlbcPass for Transform {
637    fn should_run(&self, options: &crate::options::TranslateOptions) -> bool {
638        options.ops_to_function_calls || options.index_to_function_calls
639    }
640
641    fn transform_function(&self, ctx: &mut TransformCtx, decl: &mut FunDecl) {
642        if self.item_set.contains(&ItemId::Fun(decl.def_id)) {
643            return;
644        }
645        let Some(body) = decl.body.as_structured_mut() else {
646            return;
647        };
648        if ctx.options.ops_to_function_calls {
649            body.body
650                .visit_statements(&mut |statement: &mut Statement| {
651                    transform_operation(self, ctx, statement)
652                });
653        }
654        if ctx.options.index_to_function_calls {
655            decl.transform_llbc_statements(ctx, |ctx, st: &mut Statement| {
656                let mut visitor = IndexVisitor {
657                    ctx,
658                    std_items: self,
659                    place_mutability_stack: Vec::new(),
660                };
661                use StatementKind::*;
662                match &mut st.kind {
663                    Assign(..) | SetDiscriminant(..) | Drop { .. } | Call { .. } => {
664                        let _ = visitor.visit_inner_with_mutability(st, true);
665                    }
666                    Switch { .. } | PlaceMention(..) | Borrowck(..) => {
667                        let _ = visitor.visit_inner_with_mutability(st, false);
668                    }
669                    Nop
670                    | UnwindResume
671                    | Error(..)
672                    | InlineAsm { .. }
673                    | Assert { .. }
674                    | Abort(..)
675                    | StorageDead(..)
676                    | StorageLive(..)
677                    | Return
678                    | Break(..)
679                    | Continue(..)
680                    | Loop(..) => {
681                        let _ = st.drive_body_mut(&mut visitor);
682                    }
683                }
684            })
685        }
686    }
687}
charon_lib/transform/simplify_output/builtins_to_function_calls.rs

charon_lib/transform/simplify_output/
builtins_to_function_calls.rs
