charon_driver/translate/
translate_ctx.rs

1//! The translation contexts.
2use super::translate_crate::RustcItem;
3pub use super::translate_crate::{TraitImplSource, TransItemSource, TransItemSourceKind};
4use super::translate_generics::BindingLevel;
5use charon_lib::ast::*;
6use charon_lib::formatter::{FmtCtx, IntoFormatter};
7use charon_lib::options::TranslateOptions;
8use hax::SInto;
9use rustc_middle::ty::TyCtxt;
10use std::borrow::Cow;
11use std::cell::RefCell;
12use std::collections::{BTreeSet, HashMap, HashSet};
13use std::fmt::Debug;
14use std::ops::{Deref, DerefMut};
15use std::path::PathBuf;
16use std::sync::Arc;
17use std::{fmt, mem};
18
19// Re-export to avoid having to fix imports.
20pub(crate) use charon_lib::errors::{
21    DepSource, ErrorCtx, Level, error_assert, raise_error, register_error,
22};
23
24/// Translation context used while translating the crate data into our representation.
25pub struct TranslateCtx<'tcx> {
26    /// The Rust compiler type context
27    pub tcx: TyCtxt<'tcx>,
28    /// Path to the toolchain root.
29    pub sysroot: PathBuf,
30    /// The Hax context
31    pub hax_state: hax::StateWithBase<'tcx>,
32
33    /// The options that control translation.
34    pub options: TranslateOptions,
35    /// The translated data.
36    pub translated: TranslatedCrate,
37
38    /// Record data for each method whether it is ever used (called or implemented) and the
39    /// `FunDeclId`s of the implementations. We use this to lazily translate methods, so that we
40    /// skip unused default methods of large traits like `Iterator`.
41    ///
42    /// The complete scheme works as follows: by default we enqueue no methods for translation.
43    /// When we find a use of a method, we mark it "used" using `mark_method_as_used`. This
44    /// enqueues all known and future impls of this method. We also mark a method as used if we
45    /// find an implementation of it in a non-opaque impl, and if the method is a required method.
46    pub method_status: Vector<TraitDeclId, HashMap<TraitItemName, MethodStatus>>,
47
48    /// The map from rustc id to translated id.
49    pub id_map: HashMap<TransItemSource, ItemId>,
50    /// The reverse map of ids.
51    pub reverse_id_map: HashMap<ItemId, TransItemSource>,
52    /// The reverse filename map.
53    pub file_to_id: HashMap<FileName, FileId>,
54
55    /// Context for tracking and reporting errors.
56    pub errors: RefCell<ErrorCtx>,
57    /// The declarations we came accross and which we haven't translated yet. We keep them sorted
58    /// to make the output order a bit more stable.
59    pub items_to_translate: BTreeSet<TransItemSource>,
60    /// The declaration we've already processed (successfully or not).
61    pub processed: HashSet<TransItemSource>,
62    /// Stack of the translations currently happening. Used to avoid accidental cycles.
63    pub translate_stack: Vec<ItemId>,
64    /// Cache the names to compute them only once each.
65    pub cached_names: HashMap<RustcItem, Name>,
66    /// Cache the `ItemMeta`s to compute them only once each.
67    pub cached_item_metas: HashMap<TransItemSource, ItemMeta>,
68}
69
70/// Tracks whether a method is used (i.e. called or (non-opaquely) implemented).
71#[derive(Debug)]
72pub enum MethodStatus {
73    Unused {
74        /// The `FunDeclId`s of the method implementations. Because the method is unused, these
75        /// items are not enqueued for translation yet. When marking the method as used we'll
76        /// enqueue them.
77        implementors: HashSet<FunDeclId>,
78    },
79    Used,
80}
81
82impl Default for MethodStatus {
83    fn default() -> Self {
84        Self::Unused {
85            implementors: Default::default(),
86        }
87    }
88}
89
90/// A translation context for items.
91/// Augments the [TranslateCtx] with type-level variables.
92pub(crate) struct ItemTransCtx<'tcx, 'ctx> {
93    /// The definition we are currently extracting.
94    pub item_src: TransItemSource,
95    /// The id of the definition we are currently extracting, if there is one.
96    pub item_id: Option<ItemId>,
97    /// The translation context containing the top-level definitions/ids.
98    pub t_ctx: &'ctx mut TranslateCtx<'tcx>,
99    /// The Hax context with the current `DefId`.
100    pub hax_state_with_id: hax::StateWithOwner<'tcx>,
101    /// Whether to consider a `ImplExprAtom::Error` as an error for us. True except inside type
102    /// aliases, because rust does not enforce correct trait bounds on type aliases.
103    pub error_on_impl_expr_error: bool,
104
105    /// The stack of generic parameter binders for the current context. Each binder introduces an
106    /// entry in this stack, with the entry as index `0` being the innermost binder. These
107    /// parameters are referenced using [`DeBruijnVar`]; see there for details.
108    pub binding_levels: BindingStack<BindingLevel>,
109}
110
111/// Translates `T` into `U` using `hax`'s `SInto` trait, catching any hax panics.
112pub fn catch_sinto<S, T, U>(
113    s: &S,
114    err: &mut ErrorCtx,
115    krate: &TranslatedCrate,
116    span: Span,
117    x: &T,
118) -> Result<U, Error>
119where
120    T: Debug + SInto<S, U>,
121{
122    let unwind_safe_s = std::panic::AssertUnwindSafe(s);
123    let unwind_safe_x = std::panic::AssertUnwindSafe(x);
124    std::panic::catch_unwind(move || unwind_safe_x.sinto(*unwind_safe_s)).or_else(|_| {
125        raise_error!(
126            err,
127            crate(krate),
128            span,
129            "Hax panicked when translating `{x:?}`."
130        )
131    })
132}
133
134impl<'tcx, 'ctx> TranslateCtx<'tcx> {
135    /// Span an error and register the error.
136    pub fn span_err(&self, span: Span, msg: &str, level: Level) -> Error {
137        self.errors
138            .borrow_mut()
139            .span_err(&self.translated, span, msg, level)
140    }
141
142    /// Translates `T` into `U` using `hax`'s `SInto` trait, catching any hax panics.
143    pub fn catch_sinto<S, T, U>(&mut self, s: &S, span: Span, x: &T) -> Result<U, Error>
144    where
145        T: Debug + SInto<S, U>,
146    {
147        catch_sinto(s, &mut *self.errors.borrow_mut(), &self.translated, span, x)
148    }
149
150    /// Return the polymorphic definition for this item. Use with care, prefer `hax_def` whenever
151    /// possible.
152    ///
153    /// Used for computing names, for associated items, and for various checks.
154    pub fn poly_hax_def(&mut self, def_id: &hax::DefId) -> Result<Arc<hax::FullDef>, Error> {
155        self.hax_def_for_item(&RustcItem::Poly(def_id.clone()))
156    }
157
158    /// Return the definition for this item. This uses the polymorphic or monomorphic definition
159    /// depending on user choice.
160    pub fn hax_def_for_item(&mut self, item: &RustcItem) -> Result<Arc<hax::FullDef>, Error> {
161        let def_id = item.def_id();
162        let span = self.def_span(def_id);
163        if let RustcItem::Mono(item_ref) = item
164            && item_ref.has_non_lt_param
165        {
166            raise_error!(self, span, "Item is not monomorphic: {item:?}")
167        }
168        // Hax takes care of caching the translation.
169        let unwind_safe_s = std::panic::AssertUnwindSafe(&self.hax_state);
170        std::panic::catch_unwind(move || match item {
171            RustcItem::Poly(def_id) => def_id.full_def(*unwind_safe_s),
172            RustcItem::Mono(item_ref) => item_ref.instantiated_full_def(*unwind_safe_s),
173        })
174        .or_else(|_| raise_error!(self, span, "Hax panicked when translating `{def_id:?}`."))
175    }
176
177    pub(crate) fn with_def_id<F, T>(
178        &mut self,
179        def_id: &hax::DefId,
180        item_id: Option<ItemId>,
181        f: F,
182    ) -> T
183    where
184        F: FnOnce(&mut Self) -> T,
185    {
186        let mut errors = self.errors.borrow_mut();
187        let current_def_id = mem::replace(&mut errors.def_id, item_id);
188        let current_def_id_is_local = mem::replace(&mut errors.def_id_is_local, def_id.is_local);
189        drop(errors); // important: release the refcell "lock"
190        let ret = f(self);
191        let mut errors = self.errors.borrow_mut();
192        errors.def_id = current_def_id;
193        errors.def_id_is_local = current_def_id_is_local;
194        ret
195    }
196}
197
198impl<'tcx, 'ctx> ItemTransCtx<'tcx, 'ctx> {
199    /// Create a new `ExecContext`.
200    pub(crate) fn new(
201        item_src: TransItemSource,
202        item_id: Option<ItemId>,
203        t_ctx: &'ctx mut TranslateCtx<'tcx>,
204    ) -> Self {
205        use hax::BaseState;
206        let def_id = item_src.def_id().underlying_rust_def_id();
207        let hax_state_with_id = t_ctx.hax_state.clone().with_owner_id(def_id);
208        ItemTransCtx {
209            item_src,
210            item_id,
211            t_ctx,
212            hax_state_with_id,
213            error_on_impl_expr_error: true,
214            binding_levels: Default::default(),
215        }
216    }
217
218    /// Whether to monomorphize items we encounter.
219    pub fn monomorphize(&self) -> bool {
220        matches!(self.item_src.item, RustcItem::Mono(..))
221    }
222
223    pub fn span_err(&self, span: Span, msg: &str, level: Level) -> Error {
224        self.t_ctx.span_err(span, msg, level)
225    }
226
227    pub fn hax_state(&self) -> &hax::StateWithBase<'tcx> {
228        &self.t_ctx.hax_state
229    }
230
231    pub fn hax_state_with_id(&self) -> &hax::StateWithOwner<'tcx> {
232        &self.hax_state_with_id
233    }
234
235    /// Return the definition for this item. This uses the polymorphic or monomorphic definition
236    /// depending on user choice.
237    pub fn hax_def(&mut self, item: &hax::ItemRef) -> Result<Arc<hax::FullDef>, Error> {
238        let item = if self.monomorphize() {
239            RustcItem::Mono(item.clone())
240        } else {
241            RustcItem::Poly(item.def_id.clone())
242        };
243        self.t_ctx.hax_def_for_item(&item)
244    }
245
246    pub(crate) fn poly_hax_def(&mut self, def_id: &hax::DefId) -> Result<Arc<hax::FullDef>, Error> {
247        self.t_ctx.poly_hax_def(def_id)
248    }
249}
250
251impl<'tcx> Deref for ItemTransCtx<'tcx, '_> {
252    type Target = TranslateCtx<'tcx>;
253    fn deref(&self) -> &Self::Target {
254        self.t_ctx
255    }
256}
257impl<'tcx> DerefMut for ItemTransCtx<'tcx, '_> {
258    fn deref_mut(&mut self) -> &mut Self::Target {
259        self.t_ctx
260    }
261}
262
263impl<'a> IntoFormatter for &'a TranslateCtx<'_> {
264    type C = FmtCtx<'a>;
265    fn into_fmt(self) -> Self::C {
266        self.translated.into_fmt()
267    }
268}
269
270impl<'a> IntoFormatter for &'a ItemTransCtx<'_, '_> {
271    type C = FmtCtx<'a>;
272    fn into_fmt(self) -> Self::C {
273        FmtCtx {
274            translated: Some(&self.t_ctx.translated),
275            generics: self.binding_levels.map_ref(|bl| Cow::Borrowed(&bl.params)),
276            locals: None,
277            indent_level: 0,
278        }
279    }
280}
281
282impl<'tcx, 'ctx> fmt::Display for TranslateCtx<'tcx> {
283    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
284        self.translated.fmt(f)
285    }
286}
charon_driver/translate/translate_ctx.rs

charon_driver/translate/
translate_ctx.rs
