charon_lib/
errors.rs

1//! Utilities to generate error reports about the external dependencies.
2use crate::ast::*;
3use crate::formatter::{Formatter, IntoFormatter};
4pub use annotate_snippets::Level;
5use itertools::Itertools;
6use macros::VariantIndexArity;
7use petgraph::algo::dijkstra::dijkstra;
8use petgraph::prelude::DiGraphMap;
9use std::cmp::{Ord, PartialOrd};
10use std::collections::{HashMap, HashSet};
11
12#[macro_export]
13macro_rules! register_error {
14    ($ctx:expr, crate($krate:expr), $span: expr, $($fmt:tt)*) => {{
15        let msg = format!($($fmt)*);
16        $ctx.span_err($krate, $span, &msg, $crate::errors::Level::WARNING)
17    }};
18    ($ctx:expr, $span: expr, $($fmt:tt)*) => {{
19        let msg = format!($($fmt)*);
20        $ctx.span_err($span, &msg, $crate::errors::Level::WARNING)
21    }};
22}
23pub use register_error;
24
25/// Macro to either panic or return on error, depending on the CLI options
26#[macro_export]
27macro_rules! raise_error {
28    ($($tokens:tt)*) => {{
29        return Err(register_error!($($tokens)*));
30    }};
31}
32pub use raise_error;
33
34/// Custom assert to either panic or return an error
35#[macro_export]
36macro_rules! error_assert {
37    ($ctx:expr, $span: expr, $b: expr) => {
38        if !$b {
39            $crate::errors::raise_error!($ctx, $span, "assertion failure: {:?}", stringify!($b));
40        }
41    };
42    ($ctx:expr, $span: expr, $b: expr, $($fmt:tt)*) => {
43        if !$b {
44            $crate::errors::raise_error!($ctx, $span, $($fmt)*);
45        }
46    };
47}
48pub use error_assert;
49
50/// Custom assert to report an error and optionally panic
51#[macro_export]
52macro_rules! sanity_check {
53    ($ctx:expr, $span: expr, $b: expr) => {
54        if !$b {
55            $crate::errors::register_error!(
56                $ctx,
57                $span,
58                "assertion failure: {:?}",
59                stringify!($b)
60            );
61        }
62    };
63    ($ctx:expr, $span: expr, $b: expr, $($fmt:tt)*) => {
64        if !$b {
65            $crate::errors::register_error!($ctx, $span, $($fmt)*);
66        }
67    };
68}
69pub use sanity_check;
70
71/// Common error used during the translation.
72#[derive(Debug)]
73pub struct Error {
74    pub span: Span,
75    pub msg: String,
76}
77
78impl Error {
79    pub(crate) fn render(&self, krate: &TranslatedCrate, level: Level) -> String {
80        use annotate_snippets::*;
81        let span = self.span.span;
82
83        let mut group = Group::new();
84        let origin;
85        if let Some(file) = krate.files.get(span.file_id) {
86            origin = format!("{}", file.name);
87            if let Some(source) = &file.contents {
88                let snippet = Snippet::source(source)
89                    .origin(&origin)
90                    .fold(true)
91                    .annotation(AnnotationKind::Primary.span(span.to_byte_range(source)));
92                group = group.element(snippet);
93            } else {
94                // Show just the file and line/col.
95                let origin = Origin::new(&origin)
96                    .line(span.beg.line)
97                    .char_column(span.beg.col + 1)
98                    .primary(true);
99                group = group.element(origin);
100            }
101        }
102        let message = level.header(&self.msg).group(group);
103
104        Renderer::styled().render(message).to_string()
105    }
106}
107
108/// We use this to save the origin of an id. This is useful for the external
109/// dependencies, especially if some external dependencies don't extract:
110/// we use this information to tell the user what is the code which
111/// (transitively) lead to the extraction of those problematic dependencies.
112#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
113pub struct DepSource {
114    pub src_id: AnyTransId,
115    /// The location where the id was referred to. We store `None` for external dependencies as we
116    /// don't want to show these to the users.
117    pub span: Option<Span>,
118}
119
120/// For tracing error dependencies.
121#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, VariantIndexArity)]
122enum DepNode {
123    External(AnyTransId),
124    /// We use the span information only for local references
125    Local(AnyTransId, Span),
126}
127
128/// Graph of dependencies between erroring definitions and the definitions they came from.
129struct DepGraph {
130    dgraph: DiGraphMap<DepNode, ()>,
131}
132
133impl DepGraph {
134    fn new() -> Self {
135        DepGraph {
136            dgraph: DiGraphMap::new(),
137        }
138    }
139
140    fn insert_node(&mut self, n: DepNode) {
141        // We have to be careful about duplicate nodes
142        if !self.dgraph.contains_node(n) {
143            self.dgraph.add_node(n);
144        }
145    }
146
147    fn insert_edge(&mut self, from: DepNode, to: DepNode) {
148        self.insert_node(from);
149        self.insert_node(to);
150        if !self.dgraph.contains_edge(from, to) {
151            self.dgraph.add_edge(from, to, ());
152        }
153    }
154}
155
156impl std::fmt::Display for DepGraph {
157    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
158        for (from, to, _) in self.dgraph.all_edges() {
159            writeln!(f, "{from:?} -> {to:?}")?
160        }
161        Ok(())
162    }
163}
164
165/// The context for tracking and reporting errors.
166pub struct ErrorCtx {
167    /// If true, do not abort on the first error and attempt to extract as much as possible.
168    pub continue_on_failure: bool,
169    /// If true, print the warnings as errors, and abort if any errors were raised.
170    pub error_on_warnings: bool,
171
172    /// The ids of the external_declarations for which extraction we encountered errors.
173    pub external_decls_with_errors: HashSet<AnyTransId>,
174    /// Graph of dependencies between items: there is an edge from item `a` to item `b` if `b`
175    /// registered the id for `a` during its translation. Because we only use this to report errors
176    /// on external items, we only record edges where `a` is an external item.
177    external_dep_graph: DepGraph,
178    /// The id of the definition we are exploring, used to track the source of errors.
179    pub def_id: Option<AnyTransId>,
180    /// Whether the definition being explored is local to the crate or not.
181    pub def_id_is_local: bool,
182    /// The number of errors encountered so far.
183    pub error_count: usize,
184}
185
186impl ErrorCtx {
187    pub fn new(continue_on_failure: bool, error_on_warnings: bool) -> Self {
188        Self {
189            continue_on_failure,
190            error_on_warnings,
191            external_decls_with_errors: HashSet::new(),
192            external_dep_graph: DepGraph::new(),
193            def_id: None,
194            def_id_is_local: false,
195            error_count: 0,
196        }
197    }
198
199    pub fn continue_on_failure(&self) -> bool {
200        self.continue_on_failure
201    }
202    pub fn has_errors(&self) -> bool {
203        self.error_count > 0
204    }
205
206    /// Report an error without registering anything.
207    pub fn display_error(
208        &self,
209        krate: &TranslatedCrate,
210        span: Span,
211        level: Level,
212        msg: String,
213    ) -> Error {
214        let error = Error { span, msg };
215        anstream::eprintln!("{}\n", error.render(krate, level));
216        error
217    }
218
219    /// Report and register an error.
220    pub fn span_err(
221        &mut self,
222        krate: &TranslatedCrate,
223        span: Span,
224        msg: &str,
225        level: Level,
226    ) -> Error {
227        let level = if level == Level::WARNING && self.error_on_warnings {
228            Level::ERROR
229        } else {
230            level
231        };
232        let err = self.display_error(krate, span, level, msg.to_string());
233        self.error_count += 1;
234        // If this item comes from an external crate, after the first error for that item we
235        // display where in the local crate that item was reached from.
236        if !self.def_id_is_local
237            && let Some(id) = self.def_id
238            && self.external_decls_with_errors.insert(id)
239        {
240            self.report_external_dep_error(krate, id);
241        }
242        if !self.continue_on_failure() {
243            panic!("{msg}");
244        }
245        err
246    }
247
248    /// Register the fact that `id` is a dependency of `src` (if `src` is not `None`).
249    pub fn register_dep_source(
250        &mut self,
251        src: &Option<DepSource>,
252        item_id: AnyTransId,
253        is_local: bool,
254    ) {
255        if let Some(src) = src
256            && src.src_id != item_id
257            && !is_local
258        {
259            let src_node = DepNode::External(item_id);
260            self.external_dep_graph.insert_node(src_node);
261
262            let tgt_node = match src.span {
263                Some(span) => DepNode::Local(src.src_id, span),
264                None => DepNode::External(src.src_id),
265            };
266            self.external_dep_graph.insert_edge(src_node, tgt_node)
267        }
268    }
269
270    /// In case errors happened when extracting the definitions coming from the external
271    /// dependencies, print a detailed report to explain to the user which dependencies were
272    /// problematic, and where they are used in the code.
273    pub fn report_external_dep_error(&self, krate: &TranslatedCrate, id: AnyTransId) {
274        use annotate_snippets::*;
275
276        // Use `Dijkstra's` algorithm to find the local items reachable from the current non-local
277        // item.
278        let graph = &self.external_dep_graph;
279        let reachable = dijkstra(&graph.dgraph, DepNode::External(id), None, |_| 1);
280        trace!("id: {:?}\nreachable:\n{:?}", id, reachable);
281
282        // Collect reachable local spans.
283        let by_file: HashMap<FileId, Vec<Span>> = reachable
284            .iter()
285            .filter_map(|(n, _)| match n {
286                DepNode::External(_) => None,
287                DepNode::Local(_, span) => Some(*span),
288            })
289            .into_group_map_by(|span| span.span.file_id);
290
291        // Collect to a `Vec` to be able to sort it and to borrow `origin` (needed by
292        // `Snippet::source`).
293        let mut by_file: Vec<(FileId, _, _, Vec<Span>)> = by_file
294            .into_iter()
295            .filter_map(|(file_id, mut spans)| {
296                spans.sort(); // Sort spans to display in file order
297                let file = krate.files.get(file_id)?;
298                let source = file.contents.as_ref()?;
299                let file_name = file.name.to_string();
300                Some((file_id, file_name, source, spans))
301            })
302            .collect();
303        // Sort by file id to avoid output instability.
304        by_file.sort_by_key(|(file_id, ..)| *file_id);
305
306        let level = Level::NOTE;
307        let snippets = by_file.iter().map(|(_, origin, source, spans)| {
308            Snippet::source(source)
309                .origin(&origin)
310                .fold(true)
311                .annotations(
312                    spans
313                        .iter()
314                        .map(|span| AnnotationKind::Context.span(span.span.to_byte_range(source))),
315                )
316        });
317
318        let msg = format!(
319            "the error occurred when translating `{}`, \
320             which is (transitively) used at the following location(s):",
321            krate.into_fmt().format_object(id)
322        );
323        let message = level.header(&msg).group(Group::new().elements(snippets));
324        let out = Renderer::styled().render(message).to_string();
325        anstream::eprintln!("{}", out);
326    }
327}
charon_lib/errors.rs

charon_lib/
errors.rs
